{"id": "paleo.006869", "title": "A new talpid from the late Eocene of North America", "abstract": "The origin and early evolution of talpids (moles, shrew-moles, and desmans) is not well understood, in large part due to the poor fossil record of early talpids. Here we report the oldest known talpid from North America, Oreotalpa florissantensis gen. et sp. nov., based upon a tiny dentary with m1-m3 discovered in upper Eocene (Chadronian) strata of the Florissant Formation, Florissant Fossil Beds National Monument, Colorado. Oreotalpa extends the North American record of talpids back by some six Ma and appears temporally correlative with the oldest documented talpids from the late Eocene of Europe. While others have postulated a Eurasian origin for talpids, discovery of Oreotalpa suggests that the evolution of the group was underway in North America by late Eocene time and raises the possibility of a North American origin.", "keyphrases": ["talpid", "eocene", "north america"]}
{"id": "paleo.001265", "title": "PAST: PALEONTOLOGICAL STATISTICS SOFTWARE PACKAGE FOR EDUCATION AND DATA ANALYSIS", "abstract": "A comprehensive, but simple-to-use software package for executing a range of standard numerical analysis and operations used in quantitative paleontology has been developed. The program, called PAST (PAleontological STatistics), runs on standard Windows computers and is available free of charge. PAST integrates spreadsheet-type data entry with univariate and multivariate statistics, curve fitting, timeseries analysis, data plotting, and simple phylogenetic analysis. Many of the functions are specific to paleontology and ecology, and these functions are not found in standard, more extensive, statistical packages. PAST also includes fourteen case studies (data files and exercises) illustrating use of the program for paleontological problems, making it a complete educational package for courses in quantitative methods.", "keyphrases": ["paleontological statistics", "data analysis", "program", "past", "pca"]}
{"id": "paleo.010068", "title": "Histology of \u201cplacoderm\u201d dermal skeletons: Implications for the nature of the ancestral gnathostome", "abstract": "The vertebrate dermal skeleton has long been interpreted to have evolved from a primitive condition exemplified by chondrichthyans. However, chondrichthyans and osteichthyans evolved from an ancestral gnathostome stem\u2010lineage in which the dermal skeleton was more extensively developed. To elucidate the histology and skeletal structure of the gnathostome crown\u2010ancestor we conducted a histological survey of the diversity of the dermal skeleton among the placoderms, a diverse clade or grade of early jawed vertebrates. The dermal skeleton of all placoderms is composed largely of a cancellar architecture of cellular dermal bone, surmounted by dermal tubercles in the most ancestral clades, including antiarchs. Acanthothoracids retain an ancestral condition for the dermal skeleton, and we record its secondary reduction in antiarchs. We also find that mechanisms for remodeling bone and facilitating different growth rates between adjoining plates are widespread throughout the placoderms. J. Morphol., 2013. \u00a9 2013 Wiley Periodicals, Inc.", "keyphrases": ["placoderm", "dermal skeleton", "histology"]}
{"id": "10.1002/ajpa.21442", "title": "The late Middle Pleistocene hominin fossil record of eastern Asia: synthesis and review.", "abstract": "Traditionally, Middle Pleistocene hominin fossils that cannot be allocated to Homo erectus sensu lato or modern H. sapiens have been assigned to different specific taxa. For example, in eastern Asia, these hominin fossils have been classified as archaic, early, or premodern H. sapiens. An increasing number of Middle Pleistocene hominin fossils are currently being assigned to H. heidelbergensis. This is particularly the case for the African and European Middle Pleistocene hominin fossil record. There have been suggestions that perhaps the eastern Asian late Middle Pleistocene hominins can also be allocated to the H. heidelbergensis hypodigm. In this article, I review the current state of the late Middle Pleistocene hominin fossil record from eastern Asia and examine the various arguments for assigning these hominins to the different specific taxa. The two primary conclusions drawn from this review are as follows: 1) little evidence currently exists in the eastern Asian Middle Pleistocene hominin fossil record to support their assignment to H. heidelbergensis; and 2) rather than add to the growing list of hominin fossil taxa by using taxonomic names like H. daliensis for northeast Asian fossils and H. mabaensis for Southeast Asian fossils, it is better to err on the side of caution and continue to use the term archaic H. sapiens to represent all of these hominin fossils. What should be evident from this review is the need for an increase in the quality and quantity of the eastern Asian hominin fossil data set. Fortunately, with the increasing number of large-scale multidisciplinary paleoanthropological field and laboratory research projects in eastern Asia, the record is quickly becoming better understood.", "keyphrases": ["middle pleistocene", "eastern asia", "asia"]}
{"id": "10.1111/pala.12406", "title": "Homologous shell microstructures in Cambrian hyoliths and molluscs", "abstract": "Hyoliths were among the earliest biomineralizing metazoans in Palaeozoic marine environments. They have been known for two centuries and widely assigned to lophotrochozoans. However, their origin and relationships with modern lophotrochozoan clades have been a longstanding palaeontological controversy. Here, we provide broad microstructural data from hyolith conchs and opercula from the lower Cambrian Xinji Formation of North China, including two hyolithid genera and four orthothecid genera as well as unidentified opercula. Results show that most hyolith conchs contain a distinct aragonitic lamellar layer that is composed of foliated aragonite, except in the orthothecid New taxon 1 that has a crossed foliated lamellar microstructure. Opercula are mostly composed of foliated aragonite and occasionally foliated calcite. These blade or lath\u2010like microstructural fabrics coincide well with biomineralization of Cambrian molluscs rather than lophophorates, as exemplified by the Cambrian members of the tommotiid\u2010brachiopod linage. Accordingly, we propose that hyoliths and molluscs might have inherited their biomineralized skeletons from a non\u2010mineralized or weakly mineralized common ancestor rather than as a result of convergence. Consequently, from the view of biomineralization, the homologous shell microstructures in Cambrian hyoliths and molluscs strongly strengthen the phylogenetic links between the two groups.", "keyphrases": ["shell microstructure", "hyolith", "mollusc"]}
{"id": "paleo.009631", "title": "No Ancient DNA Damage in Actinobacteria from the Neanderthal Bone", "abstract": "Background The Neanderthal genome was recently sequenced using DNA extracted from a 38,000-year-old fossil. At the start of the project, the fraction of mammalian and bacterial DNA in the sample was estimated to be <6% and 9%, respectively. Treatment with restriction enzymes prior to sequencing increased the relative proportion of mammalian DNA to 15%, but the large majority of sequences remain uncharacterized. Principal Findings Our taxonomic profiling of 3.95 Gb of Neanderthal DNA isolated from the Vindija Neanderthal Vi33.16 fossil showed that 90% of about 50,000 rRNA gene sequence reads were of bacterial origin, of which Actinobacteria accounted for more than 75%. Actinobacteria also represented more than 80% of the PCR-amplified 16S rRNA gene sequences from a cave sediment sample taken from the same G layer as the Neanderthal bone. However, phylogenetic analyses did not identify any sediment clones that were closely related to the bone-derived sequences. We analysed the patterns of nucleotide differences in the individual sequence reads compared to the assembled consensus sequences of the rRNA gene sequences. The typical ancient nucleotide substitution pattern with a majority of C to T changes indicative of DNA damage was observed for the Neanderthal rRNA gene sequences, but not for the Streptomyces-like rRNA gene sequences. Conclusions/Significance Our analyses suggest that the Actinobacteria, and especially members of the Streptomycetales, contribute the majority of sequences in the DNA extracted from the Neanderthal fossil Vi33.16. The bacterial DNA showed no signs of damage, and we hypothesize that it was derived from bacteria that have been enriched inside the bone. The bioinformatic approach used here paves the way for future studies of microbial compositions and patterns of DNA damage in bacteria from archaeological bones. Such studies can help identify targeted measures to increase the relative amount of endogenous DNA in the sample.", "keyphrases": ["dna damage", "actinobacteria", "neanderthal bone"]}
{"id": "paleo.011006", "title": "Tissue-specific geometry and chemistry of modern and fossilized melanosomes reveal internal anatomy of extinct vertebrates", "abstract": "Significance Recent reports of nonintegumentary melanosomes in fossils hint at functions for melanin beyond color production, but the biology and evolution of internal melanins are poorly understood. Our results show that internal melanosomes are widespread in diverse fossil and modern vertebrates and have tissue-specific geometries and metal chemistries. Tissue-specific chemical signatures can persist in fossils despite some diagenetic overprint, allowing the reconstruction of internal soft-tissue anatomy in fossil vertebrates, and suggest that links between melanin and metal regulation have deep evolutionary origins in vertebrates. Recent discoveries of nonintegumentary melanosomes in extant and fossil amphibians offer potential insights into the physiological functions of melanin not directly related to color production, but the phylogenetic distribution and evolutionary history of these internal melanosomes has not been characterized systematically. Here, we present a holistic method to discriminate among melanized tissues by analyzing the anatomical distribution, morphology, and chemistry of melanosomes in various tissues in a phylogenetically broad sample of extant and fossil vertebrates. Our results show that internal melanosomes in all extant vertebrates analyzed have tissue-specific geometries and elemental signatures. Similar distinct populations of preserved melanosomes in phylogenetically diverse vertebrate fossils often map onto specific anatomical features. This approach also reveals the presence of various melanosome-rich internal tissues in fossils, providing a mechanism for the interpretation of the internal anatomy of ancient vertebrates. Collectively, these data indicate that vertebrate melanins share fundamental physiological roles in homeostasis via the scavenging and sequestering of metals and suggest that intimate links between melanin and metal metabolism in vertebrates have deep evolutionary origins.", "keyphrases": ["geometry", "melanosome", "vertebrate", "metal", "integumentary tissue"]}
{"id": "10.1111/j.1095-8312.2010.01431.x", "title": "Evolution of humeral microanatomy and lifestyle in amniotes, and some comments on palaeobiological inferences", "abstract": "A study on the most exhaustive taxonomic sample of amniotes (75 extant and nine extinct taxa) of any quantitative work on this topic published so far demonstrates a strong relationship between lifestyle (aquatic, amphibious or terrestrial) and humeral microanatomy. We suggest that corrections for multiple testing be used to check for statistical artefacts in the context of a phylogenetic independent contrast analysis, and we use the false discovery rate procedure for this. Linear discriminant models segregate the various lifestyles with excellent success rate of up to 98.5%. Lifestyle was thus inferred for six extinct taxa of uncertain habitat. The results obtained suggest that Captorhinus, Claudiosaurus, and Placodus were amphibious, whereas Neusticosaurus and Mesosaurus were aquatic. Lystrosaurus may have been more aquatic than previously suggested, although the results of our inference models have to be integrated with other sources of data, which suggest that it may have been amphibious, rather than aquatic (as a literal interpretation of the models would suggest). Finally, we propose an alternative method of palaeobiological inference for hypothetical ancestors.\u00a0\u00a9 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 384\u2013406.", "keyphrases": ["humeral microanatomy", "lifestyle", "amniote", "aquatic lifestyle"]}
{"id": "paleo.010699", "title": "Biology of the sauropod dinosaurs: the evolution of gigantism", "abstract": "The herbivorous sauropod dinosaurs of the Jurassic and Cretaceous periods were the largest terrestrial animals ever, surpassing the largest herbivorous mammals by an order of magnitude in body mass. Several evolutionary lineages among Sauropoda produced giants with body masses in excess of 50 metric tonnes by conservative estimates. With body mass increase driven by the selective advantages of large body size, animal lineages will increase in body size until they reach the limit determined by the interplay of bauplan, biology, and resource availability. There is no evidence, however, that resource availability and global physicochemical parameters were different enough in the Mesozoic to have led to sauropod gigantism.", "keyphrases": ["sauropod dinosaur", "gigantism", "terrestrial animal", "body size", "biology"]}
{"id": "paleo.007458", "title": "Systematic description of putative animal fossils from the early Ediacaran Lantian Formation of South China", "abstract": "The early Ediacaran Lantian Formation in South China contains some of the oldest known representatives of morphologically complex macroorganisms, including various macroalgae and putative animals. The macroalgal fossils have been described previously in several publications, but no taxonomic treatment has been published for the putative animal fossils. This hampers our ability to fully evaluate and communicate the significance of these potentially important Ediacaran macrofossils. To address this deficiency, here we provide a systematic description of these putative animal fossils from the Lantian Formation, including four new genera and five new species: Lantianella laevis gen. et sp. nov., L. annularis gen. et sp. nov., Piyuania cyathiformis gen. et sp. nov., Qianchuania fusiformis gen. et sp. nov. and Xiuningella rara gen. et sp. nov. Morphological comparisons of these fossils and potential modern analogues are provided and critically assessed.", "keyphrases": ["animal fossil", "lantian formation", "south china"]}
{"id": "paleo.000130", "title": "Humble origins for a successful strategy: complete enrolment in early Cambrian olenellid trilobites", "abstract": "Trilobites are typified by the behavioural and morphological ability to enrol their bodies, most probably as a defence mechanism against adverse environmental conditions or predators. Although most trilobites could enrol at least partially, there is uncertainty about whether olenellids\u2014among the most phylogenetically and stratigraphically basal representatives\u2014could perform this behaviour because of their poorly caudalized trunk and scarcity of coaptative devices. Here, we report complete\u2014but not encapsulating\u2014enrolment for the olenellid genus Mummaspis from the early Cambrian Mural Formation in Alberta, the earliest direct evidence of this strategy in the fossil record of polymerid trilobites. Complete enrolment in olenellids was achieved through a combination of ancestral morphological features, and thus provides new information on the character polarity associated with this key trilobite adaptation.", "keyphrases": ["strategy", "enrolment", "trilobite"]}
{"id": "paleo.012712", "title": "Formation of the Isthmus of Panama", "abstract": "Independent evidence from rocks, fossils, and genes converge on a cohesive narrative of isthmus formation in the Pliocene. The formation of the Isthmus of Panama stands as one of the greatest natural events of the Cenozoic, driving profound biotic transformations on land and in the oceans. Some recent studies suggest that the Isthmus formed many millions of years earlier than the widely recognized age of approximately 3 million years ago (Ma), a result that if true would revolutionize our understanding of environmental, ecological, and evolutionary change across the Americas. To bring clarity to the question of when the Isthmus of Panama formed, we provide an exhaustive review and reanalysis of geological, paleontological, and molecular records. These independent lines of evidence converge upon a cohesive narrative of gradually emerging land and constricting seaways, with formation of the Isthmus of Panama sensu stricto around 2.8 Ma. The evidence used to support an older isthmus is inconclusive, and we caution against the uncritical acceptance of an isthmus before the Pliocene.", "keyphrases": ["isthmus", "panama", "gene", "cenozoic"]}
{"id": "paleo.012078", "title": "Periodontal Ligament, Cementum, and Alveolar Bone in the Oldest Herbivorous Tetrapods, and Their Evolutionary Significance", "abstract": "Tooth implantation provides important phylogenetic and functional information about the dentitions of amniotes. Traditionally, only mammals and crocodilians have been considered truly thecodont, because their tooth roots are coated in layers of cementum for anchorage of the periodontal ligament, which is in turn attached to the bone lining the alveolus, the alveolar bone. The histological properties and developmental origins of these three periodontal tissues have been studied extensively in mammals and crocodilians, but the identities of the periodontal tissues in other amniotes remain poorly studied. Early work on dental histology of basal amniotes concluded that most possess a simplified tooth attachment in which the tooth root is ankylosed to a pedestal composed of \u201cbone of attachment\u201d, which is in turn fused to the jaw. More recent studies have concluded that stereotypically thecodont tissues are also present in non-mammalian, non-crocodilian amniotes, but these studies were limited to crown groups or secondarily aquatic reptiles. As the sister group to Amniota, and the first tetrapods to exhibit dental occlusion, diadectids are the ideal candidates for studies of dental evolution among terrestrial vertebrates because they can be used to test hypotheses of development and homology in deep time. Our study of Permo-Carboniferous diadectid tetrapod teeth and dental tissues reveal the presence of two types of cementum, periodontal ligament, and alveolar bone, and therefore the earliest record of true thecodonty in a tetrapod. These discoveries in a stem amniote allow us to hypothesize that the ability to produce the tissues that characterize thecodonty in mammals and crocodilians is very ancient and plesiomorphic for Amniota. Consequently, all other forms of tooth implantation in crown amniotes are derived arrangements of one or more of these periodontal tissues and not simply ankylosis of teeth to the jaw by plesiomorphically retaining \u201cbone of attachment\u201d, as previously suggested.", "keyphrases": ["cementum", "tooth", "tissue", "periodontal ligament", "archosaur"]}
{"id": "paleo.011862", "title": "Deep learning and taphonomy: high accuracy in the classification of cut marks made on fleshed and defleshed bones using convolutional neural networks", "abstract": "Accurate identification of bone surface modifications (BSM) is crucial for the taphonomic understanding of archaeological and paleontological sites. Critical interpretations of when humans started eating meat and animal fat or when they started using stone tools, or when they occupied new continents or interacted with predatory guilds impinge on accurate identifications of BSM. Until now, interpretations of Plio-Pleistocene BSM have been contentious because of the high uncertainty in discriminating among taphonomic agents. Recently, the use of machine learning algorithms has yielded high accuracy in the identification of BSM. A branch of machine learning methods based on imaging, computer vision (CV), has opened the door to a more objective and accurate method of BSM identification. The present work has selected two extremely similar types of BSM (cut marks made on fleshed an defleshed bones) to test the immense potential of artificial intelligence methods. This CV approach not only produced the highest accuracy in the classification of these types of BSM until present (95% on complete images of BSM and 88.89% of images of only internal mark features), but it also has enabled a method for determining which inconspicuous microscopic features determine successful BSM discrimination. The potential of this method in other areas of taphonomy and paleobiology is enormous.", "keyphrases": ["high accuracy", "cut mark", "defleshed bone"]}
{"id": "10.1002/ar.a.20206", "title": "Dental morphology and variation in theropod dinosaurs: implications for the taxonomic identification of isolated teeth.", "abstract": "Isolated theropod teeth are common Mesozoic fossils and would be an important data source for paleoecology biogeography if they could be reliably identified as having come from particular taxa. However, obtaining identifications is confounded by a paucity of easily identifiable characters. Here we discuss a quantitative methodology designed to provide defensible identifications of isolated teeth using Tyrannosaurus as a comparison taxon. We created a standard data set based as much as possible on teeth of known taxonomic affinity against which to compare isolated crowns. Tooth morphology was described using measured variables describing crown length, base length and width, and derived variables related to basal shape, squatness, mesial curve shape, apex location with respect to base, and denticle size. Crown curves were described by fitting the power function Y = a + bX(0.5) to coordinate data collected from lateral-view images of mesial curve profiles. The b value from these analyses provides a measure of curvature. Discriminant analyses compared isolated teeth of various taxonomic affinities against the standard. The analyses classified known Tyrannosaurus teeth with Tyrannosaurus and separated most teeth known not to be Tyrannosaurus from Tyrannosaurus. They had trouble correctly classifying teeth that were very similar to Tyrannosaurus and for which there were few data in the standard. However, the results indicate that expanding the standard should facilitate the identification of numerous types of isolated theropod teeth.", "keyphrases": ["identification", "tooth", "width", "denticle size", "theropod tooth"]}
{"id": "10.1666/08024.1", "title": "Fidelity of variation in species composition and diversity partitioning by death assemblages: time-averaging transfers diversity from beta to alpha levels", "abstract": "Abstract Despite extensive paleoecological analyses of spatial and temporal turnover in species composition, the fidelity with which time-averaged death assemblages capture variation in species composition and diversity partitioning of living communities remains unexplored. Do death assemblages vary in composition between sites to a lesser degree than do living assemblages, as would be predicted from time-averaging? And is the higher number of species observed in death relative to living assemblages reduced with increasing spatial scale? We quantify the preservation of spatial and temporal variation in species composition using 11 regional data sets based on samples of living molluscan communities and their co-occurring time-averaged death assemblages. (1) Compositional dissimilarities among living assemblages (LA) within data sets are significantly positively rank-correlated to dissimilarities among counterpart pairs of death assemblages (DA), demonstrating that pairwise dissimilarity within a study area has a good preservation potential in the fossil record. Dissimilarity indices that downplay the abundance of dominant species return the highest live-dead agreement of variation in species composition. (2) The average variation in species composition (average dissimilarity) is consistently smaller in DAs than in LAs (9 of 11 data sets). This damping of variation might arise from DAs generally having a larger sample size, but the reduction by \u223c10\u201320% mostly persists even in size-standardized analyses (4 to 7 of 11 data sets, depending on metric). Beta diversity expressed by the number of compositionally distinct communities is also significantly reduced in death assemblages in size-standardized analyses (by \u223c25%). This damping of variation and reduction in beta diversity is in accord with the loss of temporal resolution expected from time-averaging, without invoking taphonomic bias (from differential preservation or postmortem transportation) or sample-size effects. The loss of temporal resolution should directly reduce temporal variation, and assuming time-for-space substitution owing to random walk within one habitat and/or temporal habitat shifting, it also decreases spatial variation in species composition. (3) DAs are more diverse than LAs at the alpha scale, but the difference is reduced at gamma scales because partitioning of alpha and beta components differs significantly between LAs and DAs. This indicates that the effects of time-averaging are reduced with increasing spatial scale. Thus, overall, time-averaged molluscan DAs do capture variation among samples of the living assemblage, but they tend to damp the magnitude of variation, making them a conservative means of inferring change over time or variation among regions in species composition and diversity. Rates of temporal and spatial species turnover documented in the fossil record are thus expected to be depressed relative to the turnover rates that are predicted by models of community dynamics, which assume higher temporal resolution. Finally, the capture by DAs of underlying variation in the LA implies little variation in the net preservation potential of death assemblages across environments, despite the different taphonomic pathways suggested by taphofacies studies.", "keyphrases": ["species composition", "death assemblage", "fidelity"]}
{"id": "10.1017/S0031182005007298", "title": "Paleohaemoproteus burmacis gen. n., sp. n. (Haemospororida: Plasmodiidae) from an Early Cretaceous biting midge (Diptera: Ceratopogonidae)", "abstract": "Paleohaemoproteus burmacis gen. n., sp. n. (Haemospororida: Plasmodiidae) is described from the abdominal cavity of a female biting midge (Diptera: Ceratopogonidae) preserved in 100 million year old amber from Myanmar (Burma). The description is based on the developmental stages of oocysts and sporozoites. The fossil species differs from extant species of Haemoproteus by its wide range of oocyst sizes, small sporozoites and occurrence in an extinct species of biting midge. Numerous sporozoites in the abdominal cavity suggest that the biting midge was an effective vector of this malarial parasite. Characters of the biting midge suggest that the host was a large, cold-blooded vertebrate. This is the earliest record of a malaria parasite and first indication that Early Cretaceous reptiles were infected with haemosporidial parasites.", "keyphrases": ["haemospororida", "plasmodiidae", "diptera"]}
{"id": "10.11646/palaeoentomology.3.1.14", "title": "Supplement to the Burmese (Myanmar) amber checklist and bibliography, 2020", "abstract": "This is a supplement to the Burmese (Myanmar) amber checklist and bibliography covering taxa described or recorded during 2020, plus a few earlier records that were missed previously. Up to the end of 2020, 1,859 species were recorded from Kachin amber of which 362 were named in 2020, which is the highest number of species named from any kind of amber in one year. Two species were also named from older Hkamti amber.", "keyphrases": ["burmese", "myanmar", "amber checklist"]}
{"id": "10.1144/GSL.SP.2004.228.01.18", "title": "Trace fossils in the aftermath of mass extinction events", "abstract": "Abstract Ichnology has great potential to advance our understanding of mass extinction events and yet is currently an underutilized resource in such studies. Here we review published ichnological studies for the Ordovician-Silurian, Permian-Triassic and Cretaceous-Tertiary extinction-recovery intervals. In addition, new information regarding the Triassic-Jurassic ichnological record from England, Austria and the western USA is presented. Trace fossils provide important information on the ecological response of the benthic community at such times. In the immediate post-extinction aftermath, the ichnodiversity, burrow size, depth of bioturbation, and ichnofabric index of the sediments are all much reduced. There is an increase in all these parameters through the post-extinction recovery period. In some cases, the stepwise reappearance of certain distinctive ichnotaxa (e.g. Diplocraterion, Rhizocorallium and Thalassinoides) may be of some stratigraphic use. Evidence from Permian-Triassic studies indicates that recovery took longer at low (tropical) palaeolatitudes than mid-high palaeolatitudes. Trace fossils also provide important information on palaeoenvironmental change through the extinction-recovery interval. The application of ichnology to mass extinction studies is in its infancy, but should prove a valuable tool in future research.", "keyphrases": ["aftermath", "mass extinction event", "trace fossil"]}
{"id": "10.2475/ajs.301.1.1", "title": "Empirical Relationships Between Elevation and the Stable Isotope Composition of Precipitation and Surface Waters: Considerations for Studies of Paleoelevation Change", "abstract": "A compilation of 68 studies from throughout many of the world9s mountain belts reveals an empirically consistent and linear relationship between change in elevation and change in the isotopic composition of precipitation along altitudinal transects. The isotopic composition of precipitation decreases linearly with increasing elevation in most regions of the world except in the Himalayas and at elevations >5000 m. There are no significant differences in isotopic lapse rates from most regions of the world (\u223c0.28 permil/100 m) except at the extreme latitudes where isotopic lapse rates are higher. Given information on past changes in the isotopic composition of precipitation preserved in pedogenic or authigenic minerals, this global isotopic lapse rate can be used to place numerical constraints on the topographic development of some ancient mountain belts or plateaus. There are many complicating factors that can confound interpretation of paleoelevation change based on stable isotopes, and many of these are unique to specific mountain belts or time periods. Relevant to all stable isotope based paleoelevation change studies is the temperature dependent isotope fractionation between a pedogenic or authigenic mineral and the water from which it forms. In cases where isotopic proxy minerals are sampled from localities where temperature will change simultaneously with elevation change, the apparent change in the isotopic composition of precipitation may be dampened by several permil. This suggests that samples taken from the rainshadow side of an emerging orographic barrier may be more likely to preserve isotopic changes resulting from mountain uplift than samples taken from atop a rising mountain range or plateau.", "keyphrases": ["elevation", "precipitation", "paleoelevation change"]}
{"id": "paleo.002352", "title": "EPOFIX AND VACUUM: AN EASY METHOD TO MAKE CASTS OF HARD SUBSTRATES", "abstract": "An effective and fast procedure is presented for making transparent casts of hard substrates such as bones, rock, shells, and wood. The procedure is based on a twocomponent epoxy (Epofix) that is especially suitable for cold mounting, avoiding heat, and limiting pressure impregnation that might damage fragile substrates. Critical to successful casting is the use of a vacuum chamber or a vacuum desiccator during early hardening to eliminate air bubbles. The vacuum is interrupted and turned on again to force air out and epoxy into blindending cavities; this action may be repeated. Afterward, the hardening takes place at atmospheric pressure. Unlike other embedding procedures, neither infiltration phases nor acetone \"boiling\" are necessary to produce detailed casts that are suitable for studies at micron scale and for long-term use.", "keyphrases": ["vacuum", "substrate", "epofix"]}
{"id": "paleo.010687", "title": "Combining ZooMS and zooarchaeology to study Late Pleistocene hominin behaviour at Fumane (Italy)", "abstract": "Collagen type I fingerprinting (ZooMS) has recently been used to provide either palaeoenvironmental data or to identify additional hominin specimens in Pleistocene contexts, where faunal assemblages are normally highly fragmented. However, its potential to elucidate hominin subsistence behaviour has been unexplored. Here, ZooMS and zooarchaeology have been employed in a complementary approach to investigate bone assemblages from Final Mousterian and Uluzzian contexts at Fumane cave (Italy). Both approaches produced analogous species composition, but differ significantly in species abundance, particularly highlighted by a six fold-increase in the quantity of Bos/Bison remains in the molecularly identified component. Traditional zooarchaeological methods would therefore underestimate the proportion of Bos/Bison in these levels to a considerable extent. We suggest that this difference is potentially due to percussion-based carcass fragmentation of large Bos/Bison bone diaphyses. Finally, our data demonstrates high variability in species assignment to body size classes based on bone cortical thickness and fragment size. Thus, combining biomolecular and traditional zooarchaeological methods allows us to refine our understanding of bone assemblage composition associated with hominin occupation at Fumane.", "keyphrases": ["zooms", "zooarchaeology", "italy"]}
{"id": "paleo.006123", "title": "Error rates and observer bias in dental microwear analysis using light microscopy", "abstract": "Despite the increased use of light microscopy in microwear analysis, studies that recognize observer error are scarce. Nonetheless, microwear analysis based on light microscopy may be more prone to observer bias than SEM or confocal microscopy. We measured observer error among five observers, who independently analyzed identical sets of dental wear surfaces on digital micrographs taken through a light microscope. For experienced microscopists, error in light-microscope-based microwear was of a similar magnitude to error rates for SEM-based microwear methods. Significant intraobserver error was rare among the most experienced observers and higher among inexperienced observers. However, because observers develop familiarity when repeatedly analyzing the same image, intraobserver error measured here and in other similar SEM studies may be artificially low. Interobserver error was highly significant and did not appear to diminish with experience. Nonetheless, the data collected by all observers was highly correlated. Essentially all observers found similar microwear differences between the species analyzed, even though the absolute values in the data were observer dependent. Going forward, microwear results will be more robust if observers adopt methods that ensure observer blindness, and avoid the common practice of combining data from different observers, and even from one observer when the observarions are separated by time and experience. Rather than using pre-published microwear databases of extant species as a basis for interpreting paleodiet, researchers may be better served by building shared microwear image libraries, with which observers could generate their own data for the basis of making paleodietary inferences.", "keyphrases": ["observer bias", "microwear analysis", "light microscopy"]}
{"id": "10.1101/gr.122747.111", "title": "True single-molecule DNA sequencing of a pleistocene horse bone.", "abstract": "Second-generation sequencing platforms have revolutionized the field of ancient DNA, opening access to complete genomes of past individuals and extinct species. However, these platforms are dependent on library construction and amplification steps that may result in sequences that do not reflect the original DNA template composition. This is particularly true for ancient DNA, where templates have undergone extensive damage post-mortem. Here, we report the results of the first \"true single molecule sequencing\" of ancient DNA. We generated 115.9 Mb and 76.9 Mb of DNA sequences from a permafrost-preserved Pleistocene horse bone using the Helicos HeliScope and Illumina GAIIx platforms, respectively. We find that the percentage of endogenous DNA sequences derived from the horse is higher among the Helicos data than Illumina data. This result indicates that the molecular biology tools used to generate sequencing libraries of ancient DNA molecules, as required for second-generation sequencing, introduce biases into the data that reduce the efficiency of the sequencing process and limit our ability to fully explore the molecular complexity of ancient DNA extracts. We demonstrate that simple modifications to the standard Helicos DNA template preparation protocol further increase the proportion of horse DNA for this sample by threefold. Comparison of Helicos-specific biases and sequence errors in modern DNA with those in ancient DNA also reveals extensive cytosine deamination damage at the 3' ends of ancient templates, indicating the presence of 3'-sequence overhangs. Our results suggest that paleogenomes could be sequenced in an unprecedented manner by combining current second- and third-generation sequencing approaches.", "keyphrases": ["dna", "pleistocene horse bone", "third-generation"]}
{"id": "paleo.006546", "title": "Laser-Stimulated Fluorescence in Paleontology", "abstract": "Fluorescence using ultraviolet (UV) light has seen increased use as a tool in paleontology over the last decade. Laser-stimulated fluorescence (LSF) is a next generation technique that is emerging as a way to fluoresce paleontological specimens that remain dark under typical UV. A laser\u2019s ability to concentrate very high flux rates both at the macroscopic and microscopic levels results in specimens fluorescing in ways a standard UV bulb cannot induce. Presented here are five paleontological case histories that illustrate the technique across a broad range of specimens and scales. Novel uses such as back-lighting opaque specimens to reveal detail and detection of specimens completely obscured by matrix are highlighted in these examples. The recent cost reductions in medium-power short wavelength lasers and use of standard photographic filters has now made this technique widely accessible to researchers. This technology has the potential to automate multiple aspects of paleontology, including preparation and sorting of microfossils. This represents a highly cost-effective way to address paleontology's preparatory bottleneck.", "keyphrases": ["paleontology", "lsf", "matrix", "laser-stimulated fluorescence"]}
{"id": "paleo.012268", "title": "Millennial-scale faunal record reveals differential resilience of European large mammals to human impacts across the Holocene", "abstract": "The use of short-term indicators for understanding patterns and processes of biodiversity loss can mask longer-term faunal responses to human pressures. We use an extensive database of approximately 18 700 mammalian zooarchaeological records for the last 11 700 years across Europe to reconstruct spatio-temporal dynamics of Holocene range change for 15 large-bodied mammal species. European mammals experienced protracted, non-congruent range losses, with significant declines starting in some species approximately 3000 years ago and continuing to the present, and with the timing, duration and magnitude of declines varying individually between species. Some European mammals became globally extinct during the Holocene, whereas others experienced limited or no significant range change. These findings demonstrate the relatively early onset of prehistoric human impacts on postglacial biodiversity, and mirror species-specific patterns of mammalian extinction during the Late Pleistocene. Herbivores experienced significantly greater declines than carnivores, revealing an important historical extinction filter that informs our understanding of relative resilience and vulnerability to human pressures for different taxa. We highlight the importance of large-scale, long-term datasets for understanding complex protracted extinction processes, although the dynamic pattern of progressive faunal depletion of European mammal assemblages across the Holocene challenges easy identification of \u2018static\u2019 past baselines to inform current-day environmental management and restoration.", "keyphrases": ["faunal record", "human impact", "holocene"]}
{"id": "10.1093/nsr/nwu061", "title": "The Weng'an biota and the Ediacaran radiation of multicellular eukaryotes", "abstract": "The rise of multicellularity represents a major evolutionary transition and it occurred independently in multiple eukaryote clades. Although simple multicellular organisms may have evolved in the Mesoproterozoic Era or even earlier, complex multicellular eukaryotes began to diversify only in the Ediacaran Period, just before the Cambrian explosion. Thus, the Ediacaran fossil record can provide key paleontological evidence about the early radiation of multicellular eukaryotes that ultimately culminated in the Cambrian explosion. The Ediacaran Weng'an biota in South China hosts exceptionally preserved eukaryote fossils, including various acanthomorphic acritarchs, pseudoparenchymatous thalli, tubular microfossils, and spheroidal fossils such as Megasphaera , Helicoforamina , Spiralicellula , and Caveasphaera . Many of these fossils have been interpreted as multicellular eukaryotes, although alternative interpretations have also been proposed. In this review, we critically examine these various interpretations, focusing particularly on Megasphaera , which has been variously interpreted as a sulfur-oxidizing bacterium, a unicellular protist, a mesomycetozoean-like holozoan, a volvocine green alga, a stem-group animal, or a crown-group animal. We conclude that Megasphaera is a multicellular eukaryote with evidence for cell-to-cell adhesion, a flexible membrane unconstrained by a rigid cell wall, spatial cellular differentiation, germ-soma separation, and programmed cell death. These features are inconsistent with the bacterium, unicellular protist, and mesomycetozoean-like holozoan interpretations. Thus, the surviving hypotheses, particularly the stem-group animal and algal interpretations, should be further tested with additional evidence. The Weng'an biota also hosts cellularly differentiated pseudoparenchymatous thalli with specialized reproductive structures indicative of an affinity with florideophyte red algae. The other Weng'an fossils reviewed here may also be multicellular eukaryotes, although direct cellular evidence is lacking in some and phylogenetic affinities are poorly constrained in others. The Weng'an biota offers many research opportunities to resolve the life histories and phylogenetic diversity of early multicellular eukaryotes and to illuminate the evolutionary prelude to the Cambrian explosion.", "keyphrases": ["weng'an biota", "multicellular eukaryote", "alternative interpretation"]}
{"id": "paleo.009108", "title": "Primate phylogenomics uncovers multiple rapid radiations and ancient interspecific introgression", "abstract": "Our understanding of the evolutionary history of primates is undergoing continual revision due to ongoing genome sequencing efforts. Bolstered by growing fossil evidence, these data have led to increased acceptance of once controversial hypotheses regarding phylogenetic relationships, hybridization and introgression, and the biogeographical history of primate groups. Among these findings is a pattern of recent introgression between species within all major primate groups examined to date, though little is known about introgression deeper in time. To address this and other phylogenetic questions, here, we present new reference genome assemblies for 3 Old World monkey (OWM) species: Colobus angolensis ssp. palliatus (the black and white colobus), Macaca nemestrina (southern pig-tailed macaque), and Mandrillus leucophaeus (the drill). We combine these data with 23 additional primate genomes to estimate both the species tree and individual gene trees using thousands of loci. While our species tree is largely consistent with previous phylogenetic hypotheses, the gene trees reveal high levels of genealogical discordance associated with multiple primate radiations. We use strongly asymmetric patterns of gene tree discordance around specific branches to identify multiple instances of introgression between ancestral primate lineages. In addition, we exploit recent fossil evidence to perform fossil-calibrated molecular dating analyses across the tree. Taken together, our genome-wide data help to resolve multiple contentious sets of relationships among primates, while also providing insight into the biological processes and technical artifacts that led to the disagreements in the first place.", "keyphrases": ["introgression", "gene tree discordance", "primate"]}
{"id": "paleo.006871", "title": "High-level classification of the nautiloid cephalopods: a proposal for the revision of the Treatise Part K", "abstract": "High-level classification of the nautiloid cephalopods has been largely neglected since the publication of the Russian and American treatises in the early 1960s. Although there is broad general agreement amongst specialists regarding the status of nautiloid orders, there is no real consensus or consistent approach regarding higher ranks and an array of superorders utilising various morphological features has been proposed. With work now commencing on the revision of the Treatise Part K, there is an urgent need for a methodical and standardised approach to the high-level classification of the nautiloids. The scheme proposed here utilizes the form of muscle attachment scars as a diagnostic feature at subclass level; other features (including siphuncular structures and cameral deposits) are employed at ordinal level. We recognise five subclasses of nautiloid cephalopods (Plectronoceratia, Multiceratia, Tarphyceratia nov., Orthoceratia, Nautilia) and 18 orders including the Order Rioceratida nov. which contains the new family Bactroceratidae. This scheme has the advantage of relative simplicity (it avoids the use of superorders) and presents a balanced approach which reflects the considerable morphological diversity and phylogenetic longevity of the nautiloids in comparison with the ammonoid and coleoid cephalopods. To avoid potential confusion arising in the higher levels of nautiloid classification employed in the revision of the Treatise Part K, we propose herein to replace the suffix '-oidea' at subclass level with the suffix '-ia'. Apart from removing ambiguity and clarifying the nomenclature, this approach also brings greater consistency and affinity with modern zoological classification schemes used for cephalopods. The original Treatise Part K adopted an 'abbreviated' form of name for nautiloid orders using the ending '-cerida' rather than '-ceratida' (e.g., Order Actinocerida rather than Actinoceratida). For the revision of Treatise Part K, we propose using the 'full' version of the ordinal names. This approach re-employs several order names in their original form, e.g., Ellesmeroceratida, Oncoceratida, and Tarphyceratida. For reasons of consistency, we also apply the same to ordinal names created since the original Treatise Part K; therefore, Order Bisonocerida becomes Bisonoceratida.", "keyphrases": ["nautiloid cephalopod", "revision", "high-level classification"]}
{"id": "paleo.011207", "title": "Preservation potential of keratin in deep time", "abstract": "Multiple fossil discoveries and taphonomic experiments have established the durability of keratin. The utility and specificity of antibodies to identify keratin peptides has also been established, both in extant feathers under varying treatment conditions, and in feathers from extinct organisms. Here, we show localization of feather-keratin antibodies to control and heat-treated feathers, testifying to the repeatability of initial data supporting the preservation potential of keratin. We then show new data at higher resolution that demonstrates the specific response of these antibodies to the feather matrix, we support the presence of protein in heat-treated feathers using ToF-SIMS, and we apply these methods to a fossil feather preserved in the unusual environment of sinter hot springs. We stress the importance of employing realistic conditions such as sediment burial when designing experiments intended as proxies for taphonomic processes occurring in the fossil record. Our data support the hypothesis that keratin, particularly the \u03b2-keratin that comprises feathers, has potential to preserve in fossil remains.", "keyphrases": ["keratin", "environment", "preservation potential"]}
{"id": "paleo.011208", "title": "Ancient amino acids from fossil feathers in amber", "abstract": "Ancient protein analysis is a rapidly developing field of research. Proteins ranging in age from the Quaternary to Jurassic are being used to answer questions about phylogeny, evolution, and extinction. However, these analyses are sometimes contentious, and focus primarily on large vertebrates in sedimentary fossilisation environments; there are few studies of protein preservation in fossils in amber. Here we show exceptionally slow racemisation rates during thermal degradation experiments of resin enclosed feathers, relative to previous thermal degradation experiments of ostrich eggshell, coral skeleton, and limpet shell. We also recover amino acids from two specimens of fossil feathers in amber. The amino acid compositions are broadly similar to those of degraded feathers, but concentrations are very low, suggesting that much of the original protein has been degraded and lost. High levels of racemisation in more apolar, slowly racemising amino acids suggest that some of the amino acids were ancient and therefore original. Our findings indicate that the unique fossilisation environment inside amber shows potential for the recovery of ancient amino acids and proteins.", "keyphrases": ["amino acid", "fossil feather", "amber", "resin"]}
{"id": "paleo.001853", "title": "Decimetre-scale multicellular eukaryotes from the 1.56-billion-year-old Gaoyuzhuang Formation in North China", "abstract": "Fossils of macroscopic eukaryotes are rarely older than the Ediacaran Period (635\u2013541 million years (Myr)), and their interpretation remains controversial. Here, we report the discovery of macroscopic fossils from the 1,560-Myr-old Gaoyuzhuang Formation, Yanshan area, North China, that exhibit both large size and regular morphology. Preserved as carbonaceous compressions, the Gaoyuzhuang fossils have statistically regular linear to lanceolate shapes up to 30 cm long and nearly 8 cm wide, suggesting that the Gaoyuzhuang fossils record benthic multicellular eukaryotes of unprecedentedly large size. Syngenetic fragments showing closely packed \u223c10 \u03bcm cells arranged in a thick sheet further reinforce the interpretation. Comparisons with living thalloid organisms suggest that these organisms were photosynthetic, although their phylogenetic placement within the Eukarya remains uncertain. The new fossils provide the strongest evidence yet that multicellular eukaryotes with decimetric dimensions and a regular developmental program populated the marine biosphere at least a billion years before the Cambrian Explosion.", "keyphrases": ["multicellular eukaryote", "gaoyuzhuang formation", "north china"]}
{"id": "10.1073/pnas.1403662111", "title": "Simple versus complex models of trait evolution and stasis as a response to environmental change", "abstract": "Significance Paleontologists have long argued about what the fossil record call tell us about how species evolve over long periods. Simple models such as stasis and random walks have been used to explore evolutionary patterns, but these have not always adequately captured the ways in which traits change over time in fossil species. Here we find that models with complex evolutionary dynamics are often favored, especially for fossil series that sample many populations, suggesting that the underlying evolutionary reality is likely more complex than represented by simplified\u2014though still useful\u2014models of trait change. Previous analyses of evolutionary patterns, or modes, in fossil lineages have focused overwhelmingly on three simple models: stasis, random walks, and directional evolution. Here we use likelihood methods to fit an expanded set of evolutionary models to a large compilation of ancestor\u2013descendant series of populations from the fossil record. In addition to the standard three models, we assess more complex models with punctuations and shifts from one evolutionary mode to another. As in previous studies, we find that stasis is common in the fossil record, as is a strict version of stasis that entails no real evolutionary changes. Incidence of directional evolution is relatively low (13%), but higher than in previous studies because our analytical approach can more sensitively detect noisy trends. Complex evolutionary models are often favored, overwhelmingly so for sequences comprising many samples. This finding is consistent with evolutionary dynamics that are, in reality, more complex than any of the models we consider. Furthermore, the timing of shifts in evolutionary dynamics varies among traits measured from the same series. Finally, we use our empirical collection of evolutionary sequences and a long and highly resolved proxy for global climate to inform simulations in which traits adaptively track temperature changes over time. When realistically calibrated, we find that this simple model can reproduce important aspects of our paleontological results. We conclude that observed paleontological patterns, including the prevalence of stasis, need not be inconsistent with adaptive evolution, even in the face of unstable physical environments.", "keyphrases": ["complex model", "stasis", "random walk"]}
{"id": "10.1080/02724634.1994.10011539", "title": "Theropod teeth from the Judith River Formation (Upper Cretaceous) of south-central Montana", "abstract": "Theropod teeth are some of the most diagnostic fossils from dinosaur assemblages, with taxonomic utility to the genus or even species level. One hundred and twenty-nine teeth, representing five theropod taxa, have been recovered from eight localities along a 75 km east-west transect in the Judith River Formation of south-central Montana. Unlike the pattern of distribution observed for the Judith River Formation in Alberta, no geographic or temporal differentiation of the theropod faunas seems to have occurred in this formation in south-central Montana.", "keyphrases": ["judith river formation", "south-central montana", "theropod tooth"]}
{"id": "10.1017/S0094837300008903", "title": "The evolution of locomotor stamina in tetrapods: circumventing a mechanical constraint", "abstract": "Endothermic tetrapods differ dramatically from ectothermic tetrapods in having a great capacity to sustain vigorous locomotion. I suggest that this difference reflects alternative adaptive responses to a mechanical constraint that was an inherent consequence of the vertebrate transition from aquatic to terrestrial modes of locomotion and respiration. The earliest tetrapods may not have been able to walk and breathe at the same time. Their sprawling gait and lateral vertebral bending would have required unilateral contractions of the thoracic musculature that may have interfered with the bilateral movements necessary for breathing. Modern lizards, whose locomotor and respiratory anatomy resembles that of the early tetrapods, provide support for this hypothesis because their breathing is greatly reduced during locomotor activity. Tetrapod lineages that gave rise to modern ectotherms apparently retained the constraint, becoming either highly specialized for burst activity based on anaerobic metabolism or specialized in passive mechanisms of defense against predators. The lineages from which birds and mammals are derived have undergone morphological changes that enable simultaneous running and breathing. In modern tetrapods upright posture is correlated with endothermic metabolism. This correlation may have arisen to circumvent ancestral constraints on locomotor stamina.", "keyphrases": ["locomotor stamina", "tetrapod", "mechanical constraint", "upright posture"]}
{"id": "paleo.005166", "title": "Squamates from the Jurassic and Cretaceous of North America", "abstract": "Squamates from the Mesozoic of North America have been collected since the end of the nineteenth century. To date, the fossils are known to occur in the Late Jurassic, Aptian-Albian, Cenomanian, Turonian, Santonian, Campanian, and Maastrichtian. Most of the records are from the Western Interior in the arid regions associated with the Rocky Mountains. Geographically, these records extend from central Alberta, Canada, south to northern Mexico. The earliest squamates are primitive forms of scincoideans and anguimorphans from the Late Jurassic-Early Cretaceous. At the beginning of the Late Cretaceous, the squamate fauna in North America changes dramatically to include a much greater diversity of taxa with a mix of lineages now extinct (e.g. Polyglyphanodontini, Chamopsiidae, Contogeniidae) and lineages still alive today (e.g. Anguidae, Xantusiidae, Platynota, Serpentes). The greatest diversity appears to be during the late Campanian, but diversity appears correlated with number of localities sampled and the late Campanian is the best sampled horizon in the Mesozoic of North America. The apparent sudden change in the North American squamate fauna is coincident with similar changes to other vertebrates (mammals, dinosaurs) and the opening of a land bridge with Asia. The lack of taxonomic and systematic study of the squamates from the Early Cretaceous of Asia makes comparison difficult, but it is likely that introduction of Asian taxa into North America was responsible, at least in part, for the relatively rapid change in the North American fauna. The hypotheses of an additional invasion from Asia during the Turonian is not supported, but the hypothesis of a second opening with Asia during the Santonian is weakly supported by the appearance of an iguanian in North America. Additional iguanians from the Campanian may have evolved in situ or may have entered North America from Asia as late as the mid-Campanian. Many of the most conspicuous lizards of the Late Cretaceous (Polyglyphanodontini, Chamopsiidae, paramacellodid-cordylid grade scincoideans) went extinct at the terminal Cretaceous extinction event, while most of the anguimorphans and snakes appear little affected. Amphisbaenians do not appear in North America until after the early Paleocene.", "keyphrases": ["north america", "lizard", "squamate"]}
{"id": "paleo.001620", "title": "A new large mammal from the Ypresian of Morocco: Evidence of surprising diversity of early proboscideans", "abstract": "We describe a new primitive proboscidean, Daouitherium rebouli gen. et sp. nov., from the early Ypresian of the Ouled Abdoun Basin, Morocco, which also yielded Phosphatherium. It is the earliest known large mammal from Africa and one of the oldest known proboscideans. It has true lophodont molars similar to those of Barytherium and Numidotherium. It is closer to these genera and more advanced than Phosphatherium (e.g., morphology of the mandible), but it is also primitive in striking features known also in Phosphatherium (absence of diastema, retention of two additional teeth in front of p2). A parsimony analysis of Daouitherium suggests its intermediate phylogenetic position between the basal, small Phosphatherium and the large, more derived Numidotherium and Barytherium. Daouitherium is a better candidate for the ancestry of N. koholense than Phosphatherium, but it is also specialized. Daouitherium and Numidotherium may belong to the same basal radiation of \"Barytherioidea\". However, the family referral of Daouitherium is uncertain (Numidotheriidae?). The discovery of such a large and derived proboscidean with respect to Phosphatherium in the same African beds of such antiquity is evidence of an unexpected early diversity of proboscideans and of the old origin of the order. It also supports the African origin of Proboscidea s.s.", "keyphrases": ["large mammal", "morocco", "proboscidean"]}
{"id": "paleo.000784", "title": "First African thylacocephalans from the Famennian of Morocco and their role in Late Devonian food webs", "abstract": "Thylacocephalans are enigmatic arthropods with an erratic Palaeozoic and Mesozoic fossil record. In many of the few localities where they occur, they are quite abundant. This also holds true for the Famennian Thylacocephalan Layer in the Maider (eastern Anti-Atlas of Morocco), a small epicontinental basin hosting some strata with taphonomic properties of a conservation deposit yielding exceptionally preserved gnathostomes and non-vertebrates. In a thin argillaceous interval in the earliest middle Famennian, thylacocephalans occur in such great numbers that they became eponyms of this unit. Therein, we discovered a new taxon of thylacocephalans, Concavicaris submarinus sp. nov., which represent the oldest records of thylacocephalans from Africa. In the CT-imagery, the holotype of Concavicaris submarinus sp. nov. revealed anatomical details including its eyes, appendages and other soft parts. Sedimentary facies and faunal composition of the Thylacocephalan Layer suggest that these animals populated the water column above the low-oxygen sea floor. Thus, thylacocephalans likely represented an important component of the diet of chondrichthyans and placoderms, which are quite common as well. The abundance of thylacocephalans in other conservation deposits like the Cleveland Shale (USA) and the Gogo Formation (Australia) underline their pivotal role in Late Devonian pelagic food webs.", "keyphrases": ["thylacocephalan", "famennian", "food webs"]}
{"id": "paleo.005248", "title": "Traces of the bone-eating annelid Osedax in Oligocene whale teeth and fish bones", "abstract": "The range of substrates that the bone-eating marine worm Osedax is able to consume has important implications for its evolutionary history, especially its potential link to the rise of whales. Once considered a whale specialist, recent work indicates that Osedax consumes a wide range of vertebrate remains, including whale soft tissue and the bones of mammals, birds and fishes. Traces resembling those produced by living Osedax have now been recognized for the first time in Oligocene whale teeth and fish bones from deep-water strata of the Makah, Pysht and Lincoln Creek formations in western Washington State, USA. The specimens were acid etched from concretions, and details of the borehole morphology were investigated using micro-computed tomography. Together with previously published Osedax traces from this area, our results show that by Oligocene time Osedax was able to colonize the same range of vertebrate remains that it consumes today and had a similar diversity of root morphologies. This supports the view that a generalist ability to exploit vertebrate bones may be an ancestral trait of Osedax.", "keyphrases": ["osedax", "fish bone", "oligocene whale tooth"]}
{"id": "paleo.005885", "title": "The oldest known bryozoan: Prophyllodictya (Cryptostomata) from the lower Tremadocian (Lower Ordovician) of Liujiachang, south\u2010western Hubei, central China", "abstract": "A new cryptostome bryozoan, Prophyllodictya simplex sp. nov., is described from the Nantzinkuan Formation (Lower Ordovician, lower Tremadoc) of Liujiachang, central China. This antedates the previously oldest known bryozoan by several million years. Colony morphology and the phylogenetic position of Prophyllodictya within Cryptostomata are explored. Phylogenetic analysis suggests that Cryptostomata (except Prophyllodictya) can be divided into two major groups, and that Prophyllodictya occupies a basal position in the cryptostome tree, which accords with its simple morphology and antiquity. A close relationship is evident between bryozoans from the South China palaeoplate and those from Baltica.", "keyphrases": ["bryozoan", "cryptostomata", "lower ordovician", "taxonomic diversity", "biotope"]}
{"id": "10.1666/13-085", "title": "Beyond the print\u2014virtual paleontology in science publishing, outreach, and education", "abstract": "Abstract Virtual paleontology unites a variety of computational techniques and methods for the visualization and analysis of fossils. Due to their great potential and increasing availability, these methods have become immensely popular in the last decade. However, communicating the wealth of digital information and results produced by the various techniques is still exacerbated by traditional methods of publication. Transferring and processing three-dimensional information, such as interactive models or animations, into scientific publications still poses a challenge. Here, we present different methods and applications to communicate digital data in academia, outreach and education. Three-dimensional PDFs, QR codes, anaglyph stereo imaging, and rapid prototyping\u2014methods routinely used in the engineering, entertainment, or medical industries\u2014are outlined and evaluated for their potential in science publishing and public engagement. Although limitations remain, these are simple, mostly cost-effective, and powerful tools to create novel and innovative resources for education, public engagement, or outreach.", "keyphrases": ["science publishing", "outreach", "education"]}
{"id": "10.1111/j.1096-3642.1994.tb00312.x", "title": "The evolution of the giant deer, Megaloceros giganteus (Blumenbach)", "abstract": "Abstract The giant deer, Megaloceros giganteus , is best known from its fossil occurrences in Ireland around 11 000 years ago, but has a history across Europe and Western Asia spanning 300 000-400 000 years. This paper reports a biometric study of variation and evolution in the giant deer through its history. Most early populations were as large in body size as the Irish sample, but some were distinctly smaller and others had markedly shorter limbs. Thickened skull and mandibular bones, especially marked in males, are constant throughout the species' history. Some earlier populations had antlers which were relatively smaller, more upright and differing in other details from the celebrated Irish specimens. Observed variation in body and antler form is discussed in terms of changing palaeoenvironments. Interpretation of the fighting or display roles of M. giganteus antlers needs to take account of their differing forms through time.", "keyphrases": ["giant deer", "megaloceros giganteus", "blumenbach"]}
{"id": "10.1098/rspb.2015.1003", "title": "Biotic replacement and mass extinction of the Ediacara biota", "abstract": "The latest Neoproterozoic extinction of the Ediacara biota has been variously attributed to catastrophic removal by perturbations to global geochemical cycles, \u2018biotic replacement\u2019 by Cambrian-type ecosystem engineers, and a taphonomic artefact. We perform the first critical test of the \u2018biotic replacement\u2019 hypothesis using combined palaeoecological and geochemical data collected from the youngest Ediacaran strata in southern Namibia. We find that, even after accounting for a variety of potential sampling and taphonomic biases, the Ediacaran assemblage preserved at Farm Swartpunt has significantly lower genus richness than older assemblages. Geochemical and sedimentological analyses confirm an oxygenated and non-restricted palaeoenvironment for fossil-bearing sediments, thus suggesting that oxygen stress and/or hypersalinity are unlikely to be responsible for the low diversity of communities preserved at Swartpunt. These combined analyses suggest depauperate communities characterized the latest Ediacaran and provide the first quantitative support for the biotic replacement model for the end of the Ediacara biota. Although more sites (especially those recording different palaeoenvironments) are undoubtedly needed, this study provides the first quantitative palaeoecological evidence to suggest that evolutionary innovation, ecosystem engineering and biological interactions may have ultimately caused the first mass extinction of complex life.", "keyphrases": ["mass extinction", "ediacara biota", "complex life"]}
{"id": "paleo.002950", "title": "Caudal autotomy as anti-predatory behaviour in Palaeozoic reptiles", "abstract": "Many lizards can drop a portion of their tail in response to an attack by a predator, a behaviour known as caudal autotomy. The capacity for intravertebral autotomy among modern reptiles suggests that it evolved in the lepidosaur branch of reptilian evolution, because no such vertebral features are known in turtles or crocodilians. Here we present the first detailed evidence of the oldest known case of caudal autotomy, found only among members of the Early Permian captorhinids, a group of ancient reptiles that diversified extensively and gained a near global distribution before the end-Permian mass extinction event of the Palaeozoic. Histological and SEM evidence show that these early reptiles were the first amniotes that could autotomize their tails, likely as an anti-predatory behaviour. As in modern iguanid lizards, smaller captorhinids were able to drop their tails as juveniles, presumably as a mechanism to evade a predator, whereas larger individuals may have gradually lost this ability. Caudal autotomy in captorhinid reptiles highlights the antiquity of this anti-predator behaviour in a small member of a terrestrial community composed predominantly of larger amphibian and synapsid predators.", "keyphrases": ["anti-predatory behaviour", "captorhinid", "caudal autotomy"]}
{"id": "10.1080/03115518.2012.680722", "title": "Revision of the genus Sunotettigarcta Hong, 1983 (Hemiptera, Tettigarctidae), with a new species from Daohugou, Inner Mongolia, China", "abstract": "Shu Li, Ying Wang, Dong Ren, & Hong Pang, December 2012. Revision of the genus Sunotettigarcta Hong, 1983 (Hemiptera, Tettigarctidae), with a new species from Daohugou, Inner Mongolia, China. Alcheringa 36, 501\u2013507. ISSN 0311\u20135518. A new species of fossil Tettigarctidae Sunotettigarcta hirsuta Li, Wang & Ren sp. nov., is described based on a nearly complete female specimen from the Middle Jurassic of Daohugou, Inner Mongolia, northeastern China. The diagnosis of Sunotettigarcta Hong, 1983 is emended.", "keyphrases": ["genus sunotettigarcta hong", "hemiptera", "tettigarctidae"]}
{"id": "paleo.007328", "title": "Divaricate growth habit in Williamsoniaceae (Bennettitales): unravelling the ecology of a key Mesozoic plant group", "abstract": "Representatives of Williamsoniacae (Bennettitales) are usually restored as small-leafed shrubs or low-growing trees with densely interlaced stems bifurcating or trifurcating at broad angles-a growth form referred to as divaricating. A divaricate plant architecture has evolved independently in at least 18 modern plant families, of which the majority occur in New Zealand, where they constitute more than 10 % of the flora. Botanists favour two or three hypotheses on the benefits of a divaricating habit for modern plants. One hypothesis favours the evolution of this habit to protect the foliage and reproductive structures from browsing by large mammals or large flightless birds, such as the recently extinct moa or other ratites. Another argues that this habit evolved in response to a dry, windy or frosty climate, whereas a third regards divarication as having evolved to optimise foliar light harvesting. Our evaluation of these hypotheses with respect to the ecological pressures known to have been experienced by Williamsoniaceae in the mid-Mesozoic reveals that although defence against browsing tetrapods cannot be excluded as a selective pressure that promoted divarication in Williamsoniaceae, many of the anatomical and morphological features of this family appear to represent responses to local environmental conditions. In this context, representatives of Williamsoniaceae have many characters that are convergent with members of Banksiinae (Proteaceae), suggesting adaptation to open vegetation communities on nutrient-deficient soils.\n", "keyphrases": ["williamsoniaceae", "bennettitales", "plant group"]}
{"id": "paleo.010923", "title": "Checklist and Scoring System for the Assessment of Soft Tissue Preservation in CT Examinations of Human Mummies", "abstract": "The purpose of this study was to develop a checklist for standardized assessment of soft tissue preservation in human mummies based on whole-body computed tomography examinations, and to add a scoring system to facilitate quantitative comparison of mummies. Computed tomography examinations of 23 mummies from the Capuchin Catacombs of Palermo, Sicily (17 adults, 6 children; 17 anthropogenically and 6 naturally mummified) and 7 mummies from the crypt of the Dominican Church of the Holy Spirit of Vilnius, Lithuania (5 adults, 2 children; all naturally mummified) were used to develop the checklist following previously published guidelines. The scoring system was developed by assigning equal scores for checkpoints with equivalent quality. The checklist was evaluated by intra- and inter-observer reliability. The finalized checklist was applied to compare the groups of anthropogenically and naturally mummified bodies. The finalized checklist contains 97 checkpoints and was divided into two main categories, \u201cA. Soft Tissues of Head and Musculoskeletal System\u201d and \u201cB. Organs and Organ Systems\u201d, each including various subcategories. The complete checklist had an intra-observer reliability of 98% and an inter-observer reliability of 93%. Statistical comparison revealed significantly higher values in anthropogenically compared to naturally mummified bodies for the total score and for three subcategories. In conclusion, the developed checklist allows for a standardized assessment and documentation of soft tissue preservation in whole-body computed tomography examinations of human mummies. The scoring system facilitates a quantitative comparison of the soft tissue preservation status between single mummies or mummy collections.", "keyphrases": ["scoring system", "soft tissue preservation", "human mummies"]}
{"id": "10.1017/pab.2017.1", "title": "Identifying patterns and drivers of coral diversity in the Central Indo-Pacific marine biodiversity hotspot", "abstract": "Abstract. Biodiversity hotspots are increasingly recognized as areas of high taxonomic and functional diversity. These hotspots are dynamic and shift geographically over time in response to environmental change. To identify drivers of the origin, evolution, and persistence of diversity hotspots,we investigated the diversity patterns of reef-building corals (Scleractinia) in the Central Indo-Pacific, a marine biodiversity hotspot for the last 25 Myr. We used the scleractinian fossil record (based on literature and a newly acquired fossil collection) to examine the taxonomic and functional diversity of corals from the Eocene to Pliocene. Our data identify potential drivers of coral diversity through time (and space) in the Central Indo-Pacific by constraining the timing of taxonomic turnover events and correlating them with known environmental changes. Increases in taxonomic diversity, high origination rates, and changes in abundance of functional character states indicate that the origin of the Central Indo-Pacific hotspot occurred during the Oligocene, initially through proliferation of pre-existing taxa and then by origination of new taxa. In contrast to taxonomic diversity, overall functional diversity of Central Indo-Pacific reef-building corals remained constant from the Eocene to the Pliocene. Our results identify global sea level as a main driver of diversity increase that, together with local tectonics, regulates availability of suitable habitats. Moreover, marine biodiversity hotspots develop from both the accumulation of taxa from older biodiversity hotspots and origination of new taxa. Our study demonstrates the utility of a combined literature-based and new collection approach for gaining new insights into the timing, drivers, and development of tropical biodiversity hotspots.", "keyphrases": ["coral", "central indo-pacific", "marine biodiversity hotspot"]}
{"id": "paleo.007283", "title": "Disparities in correlating microstructural to nanostructural preservation of dinosaur femoral bones", "abstract": "Osteohistological researches on dinosaurs are well documented, but descriptions of direct correlations between the bone microstructure and corresponding nanostructure are currently lacking. By applying correlative microscopy, we aimed to verify that well-preserved osteohistological features correlate with pristine fossil bone nanostructures from the femoral bones of Koreanosaurus boseongensis. The quality of nanostructural preservation was evaluated based on the preferred orientation level of apatite crystals obtained from selected area electron diffraction (SAED) patterns and by measuring the \u201carcs\u201d from the {100} and {002} diffraction rings. Unlike our expectations, our results revealed that well-preserved microstructures do not guarantee pristine nanostructures and vice versa. Structural preservation of bone from macro- to nanoscale primarily depends on original bioapatite density, and subsequent taphonomical factors such as effects from burial, pressure, influx of external elements and the rate of diagenetic alteration of apatite crystals. Our findings suggest that the efficient application of SAED analysis opens the opportunity for comprehensive nanostructural investigations of bone.", "keyphrases": ["nanostructural preservation", "femoral bone", "osteohistological feature"]}
{"id": "paleo.010823", "title": "An ammonite trapped in Burmese amber", "abstract": "Significance Aquatic organisms are rarely found in amber, but when they occur they provide invaluable evidence for the better understanding of amber taphonomy and past ecosystems. We report an ammonite and several marine gastropods alongside a mixed assemblage of intertidal and terrestrial forest floor organisms in mid-Cretaceous Burmese amber. Our discovery indicates that the Burmese amber forest was living near a dynamic and shifting coastal environment. The ammonite also provides supporting evidence for the age of the amber, which is still debated, and represents a rare example of dating using fossils present inside the amber. Amber is fossilized tree resin, and inclusions usually comprise terrestrial and, rarely, aquatic organisms. Marine fossils are extremely rare in Cretaceous and Cenozoic ambers. Here, we report a record of an ammonite with marine gastropods, intertidal isopods, and diverse terrestrial arthropods as syninclusions in mid-Cretaceous Burmese amber. We used X-ray\u2013microcomputed tomography (CT) to obtain high-resolution 3D images of the ammonite, including its sutures, which are diagnostically important for ammonites. The ammonite is a juvenile Puzosia (Bhimaites) and provides supporting evidence for a Late Albian\u2013Early Cenomanian age of the amber. There is a diverse assemblage (at least 40 individuals) of arthropods in this amber sample from both terrestrial and marine habitats, including Isopoda, Acari (mites), Araneae (spiders), Diplopoda (millipedes), and representatives of the insect orders Blattodea (cockroaches), Coleoptera (beetles), Diptera (true flies), and Hymenoptera (wasps). The incomplete preservation and lack of soft body of the ammonite and marine gastropods suggest that they were dead and underwent abrasion on the seashore before entombment. It is most likely that the resin fell to the beach from coastal trees, picking up terrestrial arthropods and beach shells and, exceptionally, surviving the high-energy beach environment to be preserved as amber. Our findings not only represent a record of an ammonite in amber but also provide insights into the taphonomy of amber and the paleoecology of Cretaceous amber forests.", "keyphrases": ["ammonite", "amber", "puzosia", "bhimaites"]}
{"id": "10.1111/pala.12587", "title": "Ontogenetic trajectories of septal spacing and conch shape in the Late Cretaceous gaudryceratid ammonoids: implications for their post\u2010embryonic palaeoecology", "abstract": "In this study, we analysed the ontogenetic trajectories of septal spacing between succeeding chambers of the gaudryceratid ammonoid, Gaudryceras tenuiliratum, which were collected in the Tomamae and Mikasa areas of Hokkaido, Japan. The ontogenetic trajectories of septal spacing in G.\u2009tenuiliratum demonstrate a general trend: two cycles of increasing to decreasing septal spacing until about the 30th septum, gradually decreasing septal spacing until about the 70th septum, and then gradually increasing septal spacing at least until about the 110th septum. The ontogenetic trajectories of the whorl expansion rate (WER) in our specimens also demonstrated that a decreasing trend changed into an increasing trend at a conch diameter of c.\u20095\u20137\u2009mm. This conch diameter corresponds to the end of the second cycle of increasing to decreasing septal spacing occurring before about the 30th septum, at which point G.\u2009tenuiliratum possibly transitioned from planktic to nektobenthic habits. No significant differences were detected in the ontogenetic trajectories of septal spacing and conch shape between the two areas, which implies that the ontogenetic trajectory patterns of septal spacing in the Late Cretaceous ammonoids were taxonomy\u2010dependent rather than environment\u2010dependent, although this should be further examined with G.\u2009tenuiliratum collected from areas outside of Hokkaido.", "keyphrases": ["septal spacing", "gaudryceratid ammonoid", "ontogenetic trajectory"]}
{"id": "paleo.005206", "title": "Exploring uncertainty in the calibration of the molecular clock", "abstract": "Calibration is a critical step in every molecular clock analysis but it has been the least considered. Bayesian approaches to divergence time estimation make it possible to incorporate the uncertainty in the degree to which fossil evidence approximates the true time of divergence. We explored the impact of different approaches in expressing this relationship, using arthropod phylogeny as an example for which we established novel calibrations. We demonstrate that the parameters distinguishing calibration densities have a major impact upon the prior and posterior of the divergence times, and it is critically important that users evaluate the joint prior distribution of divergence times used by their dating programmes. We illustrate a procedure for deriving calibration densities in Bayesian divergence dating through the use of soft maximum constraints.", "keyphrases": ["calibration", "molecular clock", "divergence time estimation", "prior distribution", "fossil calibration"]}
{"id": "paleo.004292", "title": "Early Cambrian fuxianhuiids from China reveal origin of the gnathobasic protopodite in euarthropods", "abstract": "Euarthropods owe their evolutionary and ecological success to the morphological plasticity of their appendages. Although this variability is partly expressed in the specialization of the protopodite for a feeding function in the post-deutocerebral limbs, the origin of the former structure among Cambrian representatives remains uncertain. Here, we describe Alacaris mirabilis gen. et sp. nov. from the early Cambrian Xiaoshiba Lagerst\u00e4tte in China, which reveals the proximal organization of fuxianhuiid appendages in exceptional detail. Proximally, the post-deutocerebral limbs possess an antero-posteriorly compressed protopodite with robust spines. The protopodite is attached to an endopod with more than a dozen podomeres, and an oval flap-shaped exopod. The gnathal edges of the protopodites form an axial food groove along the ventral side of the body, indicating a predatory/scavenging autecology. A cladistic analysis indicates that the fuxianhuiid protopodite represents the phylogenetically earliest occurrence of substantial proximal differentiation within stem-group Euarthropoda illuminating the origin of gnathobasic feeding.", "keyphrases": ["china", "gnathobasic protopodite", "euarthropod"]}
{"id": "10.1073/pnas.1613716114", "title": "Dinosaur incubation periods directly determined from growth-line counts in embryonic teeth show reptilian-grade development", "abstract": "Significance Little is known regarding nonavian dinosaur embryology. Embryological period relates to myriad aspects of development, life history, and evolution. In reptiles incubation is slow, whereas in birds it is remarkably rapid. Because birds are living dinosaurs, rapid incubation has been assumed for all dinosaurs. We discovered daily forming growth lines in teeth of embryonic nonavian dinosaurs revealing incubation times. These lines show slow reptilian-grade development spanning months. The rapid avian condition likely evolved within birds prior to the Cretaceous\u2013Paleogene (K\u2013Pg) mass extinction event. Prolonged incubation exposed nonavian dinosaur eggs and attending parents to destructive influences for long periods. Slow development may have affected their ability to compete with more rapidly generating populations of birds, reptiles, and mammals following the K\u2013Pg cataclysm. Birds stand out from other egg-laying amniotes by producing relatively small numbers of large eggs with very short incubation periods (average 11\u201385 d). This aspect promotes high survivorship by limiting exposure to predation and environmental perturbation, allows for larger more fit young, and facilitates rapid attainment of adult size. Birds are living dinosaurs; their rapid development has been considered to reflect the primitive dinosaurian condition. Here, nonavian dinosaurian incubation periods in both small and large ornithischian taxa are empirically determined through growth-line counts in embryonic teeth. Our results show unexpectedly slow incubation (2.8 and 5.8 mo) like those of outgroup reptiles. Developmental and physiological constraints would have rendered tooth formation and incubation inherently slow in other dinosaur lineages and basal birds. The capacity to determine incubation periods in extinct egg-laying amniotes has implications for dinosaurian embryology, life history strategies, and survivorship across the Cretaceous\u2013Paleogene mass extinction event.", "keyphrases": ["incubation period", "growth-line count", "reptilian-grade development", "egg", "embryonic tooth"]}
{"id": "10.1029/2005GL024546", "title": "Response of the ITCZ to Northern Hemisphere cooling", "abstract": "Climate simulations, using models with different levels of complexity, indicate that the north\u2010south position of the intertropical convergence zone (ITCZ) responds to changes in interhemispheric temperature contrast. Paleoclimate data on a variety of timescales suggest a similar behavior, with southward displacements of the ITCZ and associated changes in tropical atmospheric circulation during cold periods in the Northern Hemisphere. To identify a mechanism by which ITCZ displacements can be forced from the extratropics, we use a climate model with idealized geography and a simple slab ocean. We cool the northern extratropics and warm the southern extratropics to represent the asymmetric temperature changes associated with glacial\u2010interglacial and millennial\u2010scale climate variability. A southward shift in the ITCZ occurs, along with changes in the trade winds and an asymmetric response of the Hadley circulation. Changes in atmospheric heat exchange between the tropics and midlatitudes are the likely cause of this response, suggesting that this mechanism may play an important role in ITCZ displacements on timescales from decadal to glacial\u2010interglacial.", "keyphrases": ["itcz", "northern hemisphere", "intertropical convergence zone"]}
{"id": "10.1098/rsos.182111", "title": "Coupling of palaeontological and neontological reef coral data improves forecasts of biodiversity responses under global climatic change", "abstract": "Reef corals are currently undergoing climatically driven poleward range expansions, with some evidence for equatorial range retractions. Predicting their response to future climate scenarios is critical to their conservation, but ecological models are based only on short-term observations. The fossil record provides the only empirical evidence for the long-term response of organisms under perturbed climate states. The palaeontological record from the Last Interglacial (LIG; 125 000 years ago), a time of global warming, suggests that reef corals experienced poleward range shifts and an equatorial decline relative to their modern distribution. However, this record is spatio-temporally biased, and existing methods cannot account for data absence. Here, we use ecological niche modelling to estimate reef corals' realized niche and LIG distribution, based on modern and fossil occurrences. We then make inferences about modelled habitability under two future climate change scenarios (RCP4.5 and RCP8.5). Reef coral ranges during the LIG were comparable to the present, with no prominent equatorial decrease in habitability. Reef corals are likely to experience poleward range expansion and large equatorial declines under RCP4.5 and RCP8.5. However, this range expansion is probably optimistic in the face of anthropogenic climate change. Incorporation of fossil data in niche models improves forecasts of biodiversity responses under global climatic change.", "keyphrases": ["forecast", "biodiversity response", "climatic change"]}
{"id": "10.1111/j.1475-4983.2009.00895.x", "title": "Endemicity and palaeobiogeography of the Osteostraci and Galeaspida: a test of scenarios of gnathostome evolution", "abstract": "Abstract:\u2002 Armoured stem\u2010gnathostomes (jawless vertebrates previously termed \u2018ostracoderms\u2019) have long been assumed to exhibit strong endemicity. This assumption has underpinned their utility in many palaeobiogeographic studies as well as scenarios regarding the evolution and dominance of jawed vertebrates over their jawless relatives. The hypothesis of endemicity in stem\u2010gnathostomes is investigated for the first time in the light of the phylogeny of the closest relatives of jawed vertebrates \u2013 Osteostraci and Galeaspida. Palaeobiogeography of each is reconstructed using Fitch optimization and modified Brooks Parsimony Analysis. Palaeobiogeographic distributions corroborate phylogeny. Results, along with consideration of the Heterostraci, enable identification of similar patterns across groups (broad ancestral range, Early Devonian expansion, endemic and pandemic clades within each, and Middle Devonian radiation events) and inferences to the palaeogeographic relationship between major terranes (i.e. Laurentia, Baltica, Avalonia, Kara, Altaids, South China, Tarim). Comparison of basin and terrane level analyses identifies the different palaeogeographic processes responsible for the distributions of each group: sea\u2010level changes in the case of the Osteostraci and rifting in the case of the Galeaspida. The general endemic nature of the Osteostraci and Galeaspida is confirmed, and thus the hypothesis that the demise and extinction of stem\u2010gnathostomes was because of their limited dispersal capacity is supported.", "keyphrases": ["palaeobiogeography", "osteostraci", "galeaspida"]}
{"id": "10.1039/b904515e", "title": "UV-B absorbing compounds in present-day and fossil pollen, spores, cuticles, seed coats and wood: evaluation of a proxy for solar UV radiation", "abstract": "UV-B absorbing compounds (UACs) in present-day and fossil pollen, spores, cuticles, seed coats and wood have been evaluated as a proxy for past UV. This proxy may not only provide information on variation of stratospheric ozone and solar UV in the period preceding and during the Antarctic ozone hole (1974\u2013present day), but also on the development and variation of the stratospheric ozone layer and solar surface UV during the evolution of life on Earth. Sporopollenin and cutin are highly resistant biopolymers, preserving well in the geological record and contain the phenolic acids p -coumaric ( p CA) and ferulic acid (FA). p CA and FA represent a good perspective for a plant-based proxy for past surface UV radiation since they are induced by solar UV-B via the phenylpropanoid pathway (PPP). UV-B absorption by these monomers in the wall of pollen and spores and in cuticles may prevent damage to the cellular metabolism. Increased p CAand FA in pollen of Vicia faba exposed to enhanced UV-B was found in greenhouse experiments. Further correlative evidence comes from UV-absorbing compounds in spores from 1960\u20132000 comparing exposure of land plants ( Lycopodium species) to solar UV before and during ozone depletion and comparing plants from Antarctica (severe ozone depletion), Arctic, and other latitudes with less or negligible ozone depletion. Wood-derived compounds guaiacyl (G), syringyl (S), and p -hydroxyphenyl (P) are produced via the PPP. The proportions of P, G, and S in the lignin differ between various plant groups ( e.g. dicotyledons/monocotyledons, gymnosperms/ angiosperms). It is hypothesized that this lignin composition and derived physiological and physical properties of lignin (such as tree-ring wood density) has potential as a proxy for palaeo-UV climate. However validation by exposure of trees to enhanced UV is lacking. p CAand FA also form part of cutin polymers and are found in extant and fossil Ginkgo leaf cuticles as shown by thermally-assisted hydrolysis and methylation (THM)-pyrolysis-GC-MS. Potentially, the time scale for reconstruction of ozone column thickness and UV-B based on the UAC UV proxy may be decadal, centennial, millennial and possibly billenial. For further development of the UACs and p CA and FA-based UV proxy, it is necessary to obtain the UV dose\u2013response (content of UACs, p CA and FA in sporopollenin and cutin) relationships for validation, based on outdoor UV radiation manipulations experiments with plants, and comparative analysis of stored plants (herbaria) or fossil material of the same or related plant species.", "keyphrases": ["compound", "fossil pollen", "uv-b"]}
{"id": "10.1029/2001PA000749", "title": "Accurate estimation of sea surface temperatures using dissolution\u2010corrected calibrations for Mg/Ca paleothermometry", "abstract": "[1]\u00a0Paired \u03b418O and Mg/Ca measurements on the same foraminiferal shells offer the ability to independently estimate sea surface temperature (SST) changes and assess their temporal relationship to the growth and decay of continental ice sheets. The accuracy of this method is confounded, however, by the absence of a quantitative method to correct Mg/Ca records for alteration by dissolution. Here we describe dissolution-corrected calibrations for Mg/Ca-paleothermometry in which the preexponent constant is a function of size-normalized shell weight: (1) for G. ruber (212\u2013300 \u03bcm) (Mg/Ca)ruber = (0.025 wt + 0.11) e0.095T and (b) for G. sacculifer (355\u2013425 \u03bcm) (Mg/Ca)sacc = (0.0032 wt + 0.181) e0.095T. The new calibrations improve the accuracy of SST estimates and are globally applicable. With this correction, eastern equatorial Atlantic SST during the Last Glacial Maximum is estimated to be 2.9\u00b0 \u00b1 0.4\u00b0C colder than today.", "keyphrases": ["sea surface temperature", "calibration", "sst"]}
{"id": "10.1080/02724634.2011.618194", "title": "The Putative Cardiomyines (Rodentia, Cavioidea) of the Middle Miocene of Patagonia (Argentina) and the Differentiation of the Family Hydrochoeridae", "abstract": "The putative cardiomyines (Rodentia, Cavioidea) of the middle Miocene of Patagonia (Argentina) and the differentiation of the Family Hydrochoeridae Maria G. Vucetich a & Maria E. Perez a b a Departamento Cientifico Paleontologia de Vertebrados, Museo de La Plata, Paseo del Bosque s/n B1900FWA, La Plata, Buenos Aires, Argentina b Museo Paleontologico \u201cEgidio Feruglio,\u201d Av. Fontana Nro. 140, U9100GYO, Trelew, Chubut, Argentina", "keyphrases": ["rodentia", "middle miocene", "patagonia"]}
{"id": "10.1002/spp2.1279", "title": "The first pre\u2010Quaternary fossil record of the clade Mabuyidae with a comment on the enclosure of the Meckelian canal in skinks", "abstract": "We here describe the first Neogene record of the squamate clade Mabuyidae. Although this clade has a cosmopolitan distribution today, no pre\u2010Quaternary fossil record of these reptiles has so far been documented. The material comes from the locality Solnechnodolsk (Russia) and is dated to the late Miocene (MN 13). Although it comprises only jaw elements, it constitutes the first evidence of the occurrence of fossil skinks around the area of the Black Sea. The material is identical to Heremites vittatus, showing the existence of this lineage as early as the late Miocene. Thus, it may be used as a potential calibration point for further studies. The comparative anatomy of the structures of lower jaw in selected scincomorph taxa with a special reference to Mabuya group is presented. The closure of the Meckelian canal is the condition at the basal node of the clade Sphenomorphidae + Eugongylidae + Egerniidae + Mabuyidea, whereas the closed canal in Acontias (Acontidae) evolved independently. However, Sphenomorphidae (Asymblepharus and Scincella) + Eugongylidae (Ablepharus) retain a large anterior opening of the Meckelian canal, whereas only a small opening characterizes the basal node of Egerniidae and Mabuyidae, except for H. vittatus and H. septemtaeniatus. The closure of the Meckelian canal in these two taxa is less well developed in comparison with other mabuyid skinks. Thus, a heterochronic pedomorphic process might have played a role in the evolution of these skinks. The Meckelian canal condition supports the monophyly of Heremites.", "keyphrases": ["pre\u2010quaternary fossil record", "meckelian canal", "skink"]}
{"id": "paleo.003827", "title": "3D morphometric analysis of fossil canid skulls contradicts the suggested domestication of dogs during the late Paleolithic", "abstract": "Whether dogs were domesticated during the Pleistocene, when humans were hunter-gatherers, or during the Neolithic, when humans began to form permanent settlements and engage in agriculture, remains controversial. Recently discovered Paleolithic fossil skulls, Goyet dated 31,680 +/\u2212 250 YBP and Eliseevichi MAE 447/5298 dated 13,905 +/\u2212 55 YBP, were previously identified as dogs. However, new genetic studies contradict the identification of these specimens as dogs, questioning the validity of traditional measurements used to morphologically identify canid fossil skulls. We employ 3D geometric morphometric analyses to compare the cranial morphology of Goyet and Eliseevichi MAE to that of ancient and modern dogs and wolves. We demonstrate that these Paleolithic canids are definitively wolves and not dogs. Compared to mesaticephalic (wolf-like breeds) dog skulls, Goyet and Eliseevichi MAE, do not have cranial flexion and the dorsal surface of their muzzles has no concavity near the orbits. Morphologically, these early fossil canids resemble wolves, and thus no longer support the establishment of dog domestication in the Paleolithic.", "keyphrases": ["morphometric analysis", "skull", "dog"]}
{"id": "10.1073/pnas.0806143105", "title": "Deciphering the complete mitochondrial genome and phylogeny of the extinct cave bear in the Paleolithic painted cave of Chauvet", "abstract": "Retrieving a large amount of genetic information from extinct species was demonstrated feasible, but complete mitochondrial genome sequences have only been deciphered for the moa, a bird that became extinct a few hundred years ago, and for Pleistocene species, such as the woolly mammoth and the mastodon, both of which could be studied from animals embedded in permafrost. To enlarge the diversity of mitochondrial genomes available for Pleistocene species, we turned to the cave bear (Ursus spelaeus), whose only remains consist of skeletal elements. We collected bone samples from the Paleolithic painted cave of Chauvet-Pont d'Arc (France), which displays the earliest known human drawings, and contains thousands of bear remains. We selected a cave bear sternebra, radiocarbon dated to 32,000 years before present, from which we generated overlapping DNA fragments assembling into a 16,810-base pair mitochondrial genome. Together with the first mitochondrial genome for the brown bear western lineage, this study provides a statistically secured molecular phylogeny assessing the cave bear as a sister taxon to the brown bear and polar bear clade, with a divergence inferred to 1.6 million years ago. With the first mitochondrial genome for a Pleistocene carnivore to be delivered, our study establishes the Chauvet-Pont d'Arc Cave as a new reservoir for Paleogenetic studies. These molecular data enable establishing the chronology of bear speciation, and provide a helpful resource to rescue for genetic analysis archeological samples initially diagnosed as devoid of amplifiable DNA.", "keyphrases": ["mitochondrial genome", "phylogeny", "cave bear"]}
{"id": "10.1017/S0016756816000625", "title": "The first Triassic \u2018Protodonatan\u2019 (Zygophlebiidae) from China: stratigraphical implications", "abstract": "Abstract The clade Triadophlebioptera within the Odonatoptera greatly diversified and became widely distributed worldwide during the Triassic. Although abundant insect fossils have been reported from the Triassic of China, no Triassic dragonflies have been recorded. In this paper, Zygophlebia tongchuanensis sp. nov., the first species of Zygophlebiidae discovered outside the Madygen Formation of Kyrgyzstan, is described from the Middle\u2013Upper Triassic Tongchuan Formation of Shaanxi Province, northwestern China. The discovery extends the distribution of the family Zygophlebiidae in Asia, indicating a high diversity of Triadophlebioptera during Middle\u2013Late Triassic times. Combined with the palaeontological and geochronological evidence, the age of the Tongchuan Formation is considered to be Anisian \u2013 Early Carnian, and the insect-bearing layers are considered to be Ladinian.", "keyphrases": ["triassic", "zygophlebiidae", "china", "shaanxi province"]}
{"id": "10.1080/03115518.2017.1334826", "title": "Reappraisal of Austrosaurus mckillopi Longman, 1933 from the Allaru Mudstone of Queensland, Australia\u2019s first named Cretaceous sauropod dinosaur", "abstract": "Poropat, S.F., Nair, J.P., Syme, C.E., Mannion, P.D., Upchurch, P., Hocknull, S.A., Cook, A.G., Tischler, T.R. & Holland, T. XX.XXXX. 2017. Reappraisal of Austrosaurus mckillopi Longman, 1933 from the Allaru Mudstone of Queensland, Australia\u2019s first named Cretaceous sauropod dinosaur. Alcheringa 41, 543\u2013580. ISSN 0311-5518 Austrosaurus mckillopi was the first Cretaceous sauropod reported from Australia, and the first Cretaceous dinosaur reported from Queensland (northeast Australia). This sauropod taxon was established on the basis of several fragmentary presacral vertebrae (QM F2316) derived from the uppermost Lower Cretaceous (upper Albian) Allaru Mudstone, at a locality situated 77 km west-northwest of Richmond, Queensland. Prior to its rediscovery in 2014, the type site was considered lost after failed attempts to relocate it in the 1970s. Excavations at the site in 2014 and 2015 led to the recovery of several partial dorsal ribs and fragments of presacral vertebrae, all of which clearly pertained to a single sauropod dinosaur. The discovery of new material of the type individual of Austrosaurus mckillopi, in tandem with a reassessment of the material collected in the 1930s, has facilitated the rearticulation of the specimen. The resultant vertebral series comprises six presacral vertebrae\u2014the posteriormost cervical and five anteriormost dorsals\u2014in association with five left dorsal ribs and one right one. The fragmentary nature of the type specimen has historically hindered assessments of the phylogenetic affinities of Austrosaurus, as has the fact that these evaluations were often based on a subset of the type material. The reappraisal of the type series of Austrosaurus presented herein, on the basis of both external morphology and internal morphology visualized through CT data, validates it as a diagnostic titanosauriform taxon, tentatively placed in Somphospondyli, and characterized by the possession of an accessory lateral pneumatic foramen on dorsal vertebra I (a feature that appears to be autapomorphic) and by the presence of a robust ventral mid-line ridge on the centra of dorsal vertebrae I and II. The interpretation of the anteriormost preserved vertebra in Austrosaurus as a posterior cervical has also prompted the re-evaluation of an isolated, partial, posterior cervical vertebra (QM F6142, the \u2018Hughenden sauropod\u2019) from the upper Albian Toolebuc Formation (which underlies the Allaru Mudstone). Although this vertebra preserves an apparent unique character of its own (a spinopostzygapophyseal lamina fossa), it is not able to be referred unequivocally to Austrosaurus and is retained as Titanosauriformes indet. Austrosaurus mckillopi is one of the oldest known sauropods from the Australian Cretaceous based on skeletal remains and potentially provides phylogenetic and/or palaeobiogeographic context for later taxa such as Wintonotitan wattsi, Diamantinasaurus matildae and Savannasaurus elliottorum. Stephen F. Poropat* [sporopat@swin.edu.au; stephenfporopat@gmail.com] Department of Chemistry and Biotechnology, Swinburne University of Technology, John St, Hawthorn, Victoria 3122, Australia; Jay P. Nair [j.nair@uq.edu.au; jayraptor@gmail.com] School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia; Caitlin E. Syme [caitlin.syme@uqconnect.edu.au] School of Biological Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia; Philip D. Mannion [philipdmannion@gmail.com] Department of Earth Science and Engineering, Imperial College London, South Kensington Campus, London SW7 2AZ, UK; Paul Upchurch [p.upchurch@ucl.ac.uk] Department of Earth Sciences, University College London, Gower Street, London WC1E 6BT, UK; Scott A. Hocknull [scott.hocknull@qm.qld.gov.au] Geosciences, Queensland Museum, 122 Gerler Rd, Hendra, Queensland 4011, Australia; Alex G. Cook [alex.cook@y7mail.com] School of Earth Sciences, The University of Queensland, St Lucia, Queensland 4072, Australia; Travis R. Tischler [travisr.tischler@outlook.com] Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia; Timothy Holland [drtimothyholland@gmail.com] Kronosaurus Korner, 91 Goldring St, Richmond, Queensland 4822, Australia. *Also affiliated with: Australian Age of Dinosaurs Museum of Natural History, Lot 1 Dinosaur Drive, PO Box 408, Winton, Queensland 4735, Australia.", "keyphrases": ["austrosaurus mckillopi longman", "australia", "sauropod dinosaur"]}
{"id": "paleo.008581", "title": "Precursory siphuncular membranes in the body chamber of Phyllopachyceras and comparisons with other ammonoids", "abstract": "Organic membranes preserved in the rear part of the body chamber of the Late Cretaceous phylloceratid ammonite Phyllopachyceras ezoense were examined with scanning electron microscopy (SEM) on the basis of well-preserved specimens from Hokkaido, Japan. SEM observations revealed that the membranes are continuous with the siphuncular tube wall in the phragmocone and consist of two layers, both of which are made of a dark, primarily conchiolin material; namely, a thinner inner homogeneous layer and a thicker outer layer with gently inclined pillar-like units. Hence, they are interpreted as the precursory siphuncular membranes. The precursory siphuncular membranes are not associated with any other organic components such as the siphuncular sheets reported in some Paleozoic and Mesozoic ammonoids. Unlike the tube-like condition in the phragmocone, the precursory siphuncular membranes in the body chamber of the specimens examined do not form a tube shape; on the ventral side the membranes are truncated and directly contact the outer shell wall. These observations suggest that the inner and outer layers of the precursory siphuncular membranes in the body chamber were respectively formed by the siphuncular epithelium from the inner side and by the invaginated septal epithelium from the outer side. It is also postulated that at the initial stage of septal formation, the rear part of the body moved slowly forward, developing a circumsiphonal invagination of the septal epithelium. Because similar conchiolin membranes are occasionally preserved in the body chambers of other phylloceratids, the above morphogenetic process applies to all members of the Phylloceratina. The tube-shaped structure in the rear part of the body chamber of desmoceratid Damesites consists only of nacreous layer. We interpret it as a pathologically overgrown prochoanitic septal neck.", "keyphrases": ["body chamber", "ammonoid", "precursory siphuncular membrane"]}
{"id": "paleo.010576", "title": "87Sr/86Sr and 14C evidence for peccary (Tayassuidae) introduction challenges accepted historical interpretation of the 1657 Ligon map of Barbados", "abstract": "Contemporary West Indian biodiversity has been shaped by two millennia of non-native species introductions. Understanding the dynamics of this process and its legacy across extended temporal and spatial scales requires accurate knowledge of introduction timing and the species involved. Richard Ligon\u2019s 17th century account and celebrated map of early colonial Barbados records the translocation of several Old World species to the island in the post-contact era, including pigs (Sus scrofa) believed to have been released by passing sailors the century prior. Here we challenge this long-accepted historical narrative, presenting evidence that Ligon\u2019s \u201cpigs\u201d were in fact peccaries, a New World continental mammal often confused with wild boars. We document the first recorded instance of non-native peccary (Tayassuidae) on Barbados based on a securely identified mandibular specimen from a historic archaeological context. Results of specimen 87Sr/86Sr and AMS radiocarbon assays, along with newly reported data from Sr isotope environmental analyses, indicate a local origin dating to AD 1645\u20131670/1780\u20131800. These data support the presence of living peccary on Barbados some time during the first 175 years of English settlement, which, based on review of historical and archaeological data, most likely arises from 16th century peccary introduction from the Guianas/Trinidad by the Spanish or Portuguese. We argue dimorphic representations of \u201cpigs\u201d on Ligon\u2019s map reflect the co-occurrence of peccary and European domestic swine on historic Barbados. Our findings overturn conventional history and provide greater taxonomic and chronological resolution for Caribbean bioinvasion studies, helping to refine our understanding of potential ecological impacts. In addition, the new bioavailable 87Sr/86Sr data for Barbados reported here advance current efforts toward mapping the Caribbean Sr isoscape.", "keyphrases": ["peccary", "tayassuidae", "guianas"]}
{"id": "paleo.011415", "title": "Best Practices for Justifying Fossil Calibrations", "abstract": "Our ability to correlate biological evolution with climate change, geological evolution, and other historical patterns is essential to understanding the processes that shape biodiversity. Combining data from the fossil record with molecular phylogenetics represents an exciting synthetic approach to this challenge. The first molecular divergence dating analysis (Zuckerkandl and Pauling 1962) was based on a measure of the amino acid differences in the hemoglobin molecule, with replacement rates established (calibrated) using paleontological age estimates from textbooks (e.g., Dodson 1960). Since that time, the amount of molecular sequence data has increased dramatically, affording ever-greater opportunities to apply molecular divergence approaches to fundamental problems in evolutionary biology. To capitalize on these opportunities, increasingly sophisticated divergence dating methods have been, and continue to be, developed. In contrast, comparatively, little attention has been devoted to critically assessing the paleontological and associated geological data used in divergence dating analyses. The lack of rigorous protocols for assigning calibrations based on fossils raises serious questions about the credibility of divergence dating results (e.g., Shaul and Graur 2002; Brochu et al. 2004; Graur and Martin 2004; Hedges and Kumar 2004; Reisz and Muller 2004a, 2004b; Theodor 2004; van Tuinen and Hadly 2004a, 2004b; van Tuinen et al. 2004; Benton and Donoghue 2007; Donoghue and Benton 2007; Parham and Irmis 2008; Ksepka 2009; Benton et al. 2009; Heads 2011). \n \nThe assertion that incorrect calibrations will negatively influence divergence dating studies is not controversial. Attempts to identify incorrect calibrations through the use of a posteriori methods are available (e.g., Near and Sanderson 2004; Near et al. 2005; Rutschmann et al. 2007; Marshall 2008; Pyron 2010; Dornburg et al. 2011). We do not deny that a posteriori methods are a useful means of evaluating calibrations, but there can be no substitute for a priori assessment of the veracity of paleontological data. \n \nIncorrect calibrations, those based upon fossils that are phylogenetically misplaced or assigned incorrect ages, clearly introduce error into an analysis. Consequently, thorough and explicit justification of both phylogenetic and chronologic age assessments is necessary for all fossils used for calibration. Such explicit justifications will help to ensure that divergence dating studies are based on the best available data. Unfortunately, the majority of previously published calibrations lack explicit explanations and justifications of the age and phylogenetic position of the key fossils. In the absence of explicit justifications, it is difficult to distinguish between correct and incorrect calibrations, and it becomes difficult to reevaluate previous claims in light of new data. Paleontology is a dynamic science, with new data and perspectives constantly emerging as a result of new discoveries (see Kimura 2010 for a recent case where the age of the earliest known record of a clade was more than doubled). Calibrations based upon the best available evidence at a given time can become inappropriate as the discovery of new specimens, new phylogenetic analyses, and ongoing stratigraphic and geochronologic revisions refine our understanding of the fossil record. \n \nOur primary goals in this paper are to establish the best practices for justifying fossils used for the temporal calibration of molecular phylogenies. Our examples derive mainly, but not exclusively, from the vertebrate fossil record. We hope that our recommendations will lead to more credible calibrations and, as a result, more reliable divergence dates throughout the tree of life. A secondary goal is to help the community (researchers, editors, and reviewers) who might be unfamiliar with fossils to understand and overcome the challenges associated with using paleontological data. In order to accomplish these goals, we present a specimen-based protocol for selecting and documenting relevant fossils and discuss future directions for evaluating and utilizing phylogenetic and temporal data from the fossil record. We likewise encourage biologists relying on nonfossil calibrations for molecular divergence estimates (e.g., ages of island or mountain range formations, continental drift, and biomarkers) to develop their own set of rigorous guidelines so that their calibrations may also be evaluated in a systematic way.", "keyphrases": ["fossil calibration", "age estimate", "error", "good practice", "node"]}
{"id": "10.1029/2002PA000771", "title": "Past extent of sea ice in the northern North Atlantic inferred from foraminiferal paleotemperature estimates", "abstract": "[1]\u00a0Using 150 core top samples, we developed a conservative but fairly robust new measure to reconstruct past changes in (maximum) seasonal sea ice distribution in the northern North Atlantic, hitherto a major unknown. The proxy is based on Similarity Maximum Modern-Analog Technique (SIMMAX) estimates of threshold temperatures near the sea surface (SST). Today, almost 100% of all sites with SST >2.5\u00b0C during summer, >0.4\u00b0 for winters 1978\u20131987, and >0.75\u00b0C for Little Ice Age winters lie seaward of the sea ice margin. When applied to >60 sediment records of the Last Glacial Maximum, this proxy shows that peak glacial sea ice was far more restricted than in the \u201cclassic\u201d CLIMAP Project Members [1981] reconstruction. During glacial summer, sea ice only covered the Arctic Ocean and western Fram Strait. The northern North Atlantic and Nordic Seas were largely ice-free and thus formed a high-latitude moisture source for the continued buildup of continental ice sheets. In contrast, sea ice spread far south across the Iceland Faeroe Ridge during glacial winter, with an inferred patch of sea ice also in the central east Atlantic, near the center of the Azores High. A broad ice-free channel extended from 50\u00b0 to 60\u00b0N, forming an ideal site for large-scale convection of glacial upper North Atlantic Deep Water. The extreme seasonality in glacial sea ice formation and melt in the Nordic Seas implies a major consumption of the regional energy income.", "keyphrases": ["sea ice", "north atlantic", "seasonality"]}
{"id": "10.1126/science.aau2422", "title": "U-Pb constraints on pulsed eruption of the Deccan Traps across the end-Cretaceous mass extinction", "abstract": "Two timelines for extinction The Cretaceous-Paleogene extinction that wiped out the nonavian dinosaurs 66 million years ago was correlated with two extreme events: The Chicxulub impact occurred at roughly the same time that massive amounts of lava were erupting from the Deccan Traps (see the Perspective by Burgess). Sprain et al. used argon-argon dating of the volcanic ash from the Deccan Traps to argue that a steady eruption of the flood basalts mostly occurred after the Chicxulub impact. Schoene et al. used uranium-lead dating of zircons from ash beds and concluded that four large magmatic pulses occurred during the flood basalt eruption, the first of which preceded the Chicxulub impact. Whatever the correct ordering of events, better constraints on the timing and rates of the eruption will help elucidate how volcanic gas influenced climate. Science, this issue p. 866, p. 862; see also p. 815 Large amounts of volcanism may have preceded the large impact associated with the demise of nonavian dinosaurs. Temporal correlation between some continental flood basalt eruptions and mass extinctions has been proposed to indicate causality, with eruptive volatile release driving environmental degradation and extinction. We tested this model for the Deccan Traps flood basalt province, which, along with the Chicxulub bolide impact, is implicated in the Cretaceous-Paleogene (K-Pg) extinction approximately 66 million years ago. We estimated Deccan eruption rates with uranium-lead (U-Pb) zircon geochronology and resolved four high-volume eruptive periods. According to this model, maximum eruption rates occurred before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction. These findings support extinction models that incorporate both catastrophic events as drivers of environmental deterioration associated with the K-Pg extinction and its aftermath.", "keyphrases": ["eruption", "deccan traps", "mass extinction", "volcanism"]}
{"id": "10.7554/eLife.19568", "title": "New footprints from Laetoli (Tanzania) provide evidence for marked body size variation in early hominins", "abstract": "Laetoli is a well-known palaeontological locality in northern Tanzania whose outstanding record includes the earliest hominin footprints in the world (3.66 million years old), discovered in 1978 at Site G and attributed to Australopithecus afarensis. Here, we report hominin tracks unearthed in the new Site S at Laetoli and referred to two bipedal individuals (S1 and S2) moving on the same palaeosurface and in the same direction as the three hominins documented at Site G. The stature estimates for S1 greatly exceed those previously reconstructed for Au. afarensis from both skeletal material and footprint data. In combination with a comparative reappraisal of the Site G footprints, the evidence collected here embodies very important additions to the Pliocene record of hominin behaviour and morphology. Our results are consistent with considerable body size variation and, probably, degree of sexual dimorphism within a single species of bipedal hominins as early as 3.66 million years ago. DOI: http://dx.doi.org/10.7554/eLife.19568.001", "keyphrases": ["footprint", "tanzania", "body size variation"]}
{"id": "paleo.009189", "title": "Experimental taphonomy of fish - role of elevated pressure, salinity and pH", "abstract": "Experiments are reported to reconstruct the taphonomic pathways of fish toward fossilisation. Acrylic glass autoclaves were designed that allow experiments to be carried out at elevated pressure up to 11 bar, corresponding to water depths of 110 m. Parameters controlled or monitored during decay reactions are pressure, salinity, proton activities (pH), electrochemical potentials (Eh), and bacterial populations. The most effective environmental parameters to delay or prevent putrefaction before a fish carcass is embedded in sediment are (1) a hydrostatic pressure in the water column high enough that a fish carcass may sink to the bottom sediment, (2) hypersaline conditions well above seawater salinity, and (3) a high pH to suppress the reproduction rate of bacteria. Anoxia, commonly assumed to be the key parameter for excellent preservation, is important in keeping the bottom sediment clear of scavengers but it does not seem to slow down or prevent putrefaction. We apply our results to the world-famous Konservat-Lagerst\u00e4tten Eichst\u00e4tt-Solnhofen, Green River, and Messel where fish are prominent fossils, and reconstruct from the sedimentary records the environmental conditions that may have promoted preservation. For Eichst\u00e4tt-Solnhofen an essential factor may have been hypersaline conditions. Waters of the Green River lakes were at times highly alkaline and hypersaline because the lake stratigraphy includes horizons rich in sodium carbonate and halite. In the Messel lake sediments some fossiliferous horizons are rich in FeCO3 siderite, a mineral indicating highly reduced conditions and a high pH.", "keyphrases": ["pressure", "salinity", "fish carcass"]}
{"id": "paleo.007491", "title": "The radiation of cynodonts and the ground plan of mammalian morphological diversity", "abstract": "Cynodont therapsids diversified extensively after the Permo-Triassic mass extinction event, and gave rise to mammals in the Jurassic. We use an enlarged and revised dataset of discrete skeletal characters to build a new phylogeny for all main cynodont clades from the Late Permian to the Early Jurassic, and we analyse models of morphological diversification in the group. Basal taxa and epicynodonts are paraphyletic relative to eucynodonts, and the latter are divided into cynognathians and probainognathians, with tritylodonts and mammals forming sister groups. Disparity analyses reveal a heterogeneous distribution of cynodonts in a morphospace derived from cladistic characters. Pairwise morphological distances are weakly correlated with phylogenetic distances. Comparisons of disparity by groups and through time are non-significant, especially after the data are rarefied. A disparity peak occurs in the Early/Middle Triassic, after which period the mean disparity fluctuates little. Cynognathians were characterized by high evolutionary rates and high diversity early in their history, whereas probainognathian rates were low. Community structure may have been instrumental in imposing different rates on the two clades.", "keyphrases": ["cynodont", "morphological diversity", "rise"]}
{"id": "paleo.008925", "title": "Non-integumentary melanosomes can bias reconstructions of the colours of fossil vertebrates", "abstract": "The soft tissues of many fossil vertebrates preserve evidence of melanosomes\u2014micron-scale organelles that inform on integumentary coloration and communication strategies. In extant vertebrates, however, melanosomes also occur in internal tissues. Hence, fossil melanosomes may not derive solely from the integument and its appendages. Here, by analyzing extant and fossil frogs, we show that non-integumentary melanosomes have high fossilization potential, vastly outnumber those from the skin, and potentially dominate the melanosome films preserved in some fossil vertebrates. Our decay experiments show that non-integumentary melanosomes usually remain in situ provided that carcasses are undisturbed. Micron-scale study of fossils, however, demonstrates that non-integumentary melanosomes can redistribute through parts of the body if carcasses are disturbed by currents. Collectively, these data indicate that fossil melanosomes do not always relate to integumentary coloration. Integumentary and non-integumentary melanosomes can be discriminated using melanosome geometry and distribution. This is essential to accurate reconstructions of the integumentary colours of fossil vertebrates.", "keyphrases": ["colour", "fossil vertebrate", "tissue", "non-integumentary melanosome"]}
{"id": "10.1177/0959683615581203", "title": "Reconstruction of the geographic extent of drought anomalies in northwestern China over the last 539\u2009years and its teleconnection with the Pacific Ocean", "abstract": "Recent paleo-climatic/environmental studies have resulted in several high-resolution paleo-precipitation/moisture reconstructions in Northwestern (NW) China over extended periods. Nevertheless, those reconstructions are mostly about the climatic history of individual sites, while fine-grained portrayal and analysis of the geographic extent of drought anomalies across the entire NW China are still missing. We based our study on the dryness/wetness grade series of 19 sites in NW China, which are primarily derived from historical documents, to reconstruct the annual geographic extent of drought anomalies in NW China in AD 1470\u20132008. Our reconstruction reveals the following periods of drought in NW China: the AD 1470s\u20131490s, 1620s\u20131640s, 1700s\u20131720s, 1770s\u20131790s, 1860s\u20131870s, and 1910s\u20131930s. The most extremely dry years were AD 1928 and 1929. In addition, we found that the influence of El Ni\u00f1o Southern Oscillation (ENSO) on the geographic extent of drought anomalies in NW China was non-stationary at the inter-annual to multi-decadal timescale and that the correlation switched from positive to negative since the late \u2018Little Ice Age\u2019. We propose that this non-stationary relationship is attributable to the variance of ENSO and the strength of Asian Summer Monsoon. To conclude, we discuss the implications of the above findings within the context of global warming.", "keyphrases": ["geographic extent", "drought anomaly", "historical document"]}
{"id": "10.1073/pnas.1802138115", "title": "Arthropods in modern resins reveal if amber accurately recorded forest arthropod communities", "abstract": "Significance It is not known whether the fossil content of amber accurately represents the arthropod biodiversity of past forests, and if and how those fossils can be compared with recent fauna for studies and predictions of biodiversity change through time. Our study of arthropods (mainly insects and spiders) living around the resinous angiosperm tree Hymenaea verrucosa Gaertner, 1791 in the lowland coastal forest of Madagascar, and arthropods trapped by the resin produced by this tree species, demonstrates that amber does not record the true past biodiversity of the entire forest. However, our results reveal how taphonomic processes, arthropod behaviors, and ecological relationships can influence arthropod death assemblages in resins and play a crucial role in controlling their taxonomic compositions. Amber is an organic multicompound derivative from the polymerization of resin of diverse higher plants. Compared with other modes of fossil preservation, amber records the anatomy of and ecological interactions between ancient soft-bodied organisms with exceptional fidelity. However, it is currently suggested that ambers do not accurately record the composition of arthropod forest paleocommunities, due to crucial taphonomic biases. We evaluated the effects of taphonomic processes on arthropod entrapment by resin from the plant Hymenaea, one of the most important resin-producing trees and a producer of tropical Cenozoic ambers and Anthropocene (or subfossil) resins. We statistically compared natural entrapment by Hymenaea verrucosa tree resin with the ensemble of arthropods trapped by standardized entomological traps around the same tree species. Our results demonstrate that assemblages in resin are more similar to those from sticky traps than from malaise traps, providing an accurate representation of the arthropod fauna living in or near the resiniferous tree, but not of entire arthropod forest communities. Particularly, arthropod groups such as Lepidoptera, Collembola, and some Diptera are underrepresented in resins. However, resin assemblages differed slightly from sticky traps, perhaps because chemical compounds in the resins attract or repel specific insect groups. Ground-dwelling or flying arthropods that use the tree-trunk habitat for feeding or reproduction are also well represented in the resin assemblages, implying that fossil inclusions in amber can reveal fundamental information about biology of the past. These biases have implications for the paleoecological interpretation of the fossil record, principally of Cenozoic amber with angiosperm origin.", "keyphrases": ["resin", "forest", "arthropod"]}
{"id": "paleo.004980", "title": "Diverse Cretaceous larvae reveal the evolutionary and behavioural history of antlions and lacewings", "abstract": "Myrmeleontiformia are an ancient group of lacewing insects characterized by predatory larvae with unusual morphologies and behaviours. Mostly soil dwellers with a soft cuticle, their larvae fossilize only as amber inclusions, and thus their fossil record is remarkably sparse. Here, we document a disparate assemblage of myrmeleontiform larvae from the mid-Cretaceous amber (99 Ma) of Myanmar, evidence of a considerable diversification. Our cladistic analysis integrating extant and extinct taxa resolves the fossils as both stem- and crown-groups. Similarities between extinct and extant species permit inferences of larval ethology of the fossil species through statistical correlation analyses with high support, implying that morphological disparity matched behavioural diversity. An improved understanding of the evolutionary history of antlions and relatives supports the conclusion that hunting strategies, such as camouflage and fossoriality, were acquired early within the lineage.", "keyphrases": ["larvae", "amber", "myanmar"]}
{"id": "paleo.010115", "title": "The Impact of Global Warming and Anoxia on Marine Benthic Community Dynamics: an Example from the Toarcian (Early Jurassic)", "abstract": "The Pliensbachian-Toarcian (Early Jurassic) fossil record is an archive of natural data of benthic community response to global warming and marine long-term hypoxia and anoxia. In the early Toarcian mean temperatures increased by the same order of magnitude as that predicted for the near future; laminated, organic-rich, black shales were deposited in many shallow water epicontinental basins; and a biotic crisis occurred in the marine realm, with the extinction of approximately 5% of families and 26% of genera. High-resolution quantitative abundance data of benthic invertebrates were collected from the Cleveland Basin (North Yorkshire, UK), and analysed with multivariate statistical methods to detect how the fauna responded to environmental changes during the early Toarcian. Twelve biofacies were identified. Their changes through time closely resemble the pattern of faunal degradation and recovery observed in modern habitats affected by anoxia. All four successional stages of community structure recorded in modern studies are recognised in the fossil data (i.e. Stage III: climax; II: transitional; I: pioneer; 0: highly disturbed). Two main faunal turnover events occurred: (i) at the onset of anoxia, with the extinction of most benthic species and the survival of a few adapted to thrive in low-oxygen conditions (Stages I to 0) and (ii) in the recovery, when newly evolved species colonized the re-oxygenated soft sediments and the path of recovery did not retrace of pattern of ecological degradation (Stages I to II). The ordination of samples coupled with sedimentological and palaeotemperature proxy data indicate that the onset of anoxia and the extinction horizon coincide with both a rise in temperature and sea level. Our study of how faunal associations co-vary with long and short term sea level and temperature changes has implications for predicting the long-term effects of \u201cdead zones\u201d in modern oceans.", "keyphrases": ["global warming", "anoxia", "early jurassic"]}
{"id": "10.1093/aob/mcx173", "title": "Fossil flowers from the early Palaeocene of Patagonia, Argentina, with affinity to Schizomerieae (Cunoniaceae)", "abstract": "Abstract Background and Aims Early Palaeocene (Danian) plant fossils from Patagonia provide information on the recovery from the end-Cretaceous extinction and Cenozoic floristic change in South America. Actinomorphic flowers with eight to ten perianth parts are described and evaluated in a phylogenetic framework. The goal of this study is to determine the identity of these fossil flowers and to discuss their evolutionary, palaeoecological and biogeographical significance Methods More than 100 fossilized flowers were collected from three localities in the Danian Salamanca and Pe\u00f1as Coloradas Formations in southern Chubut. They were prepared, photographed and compared with similar extant and fossil flowers using published literature and herbarium specimens. Phylogenetic analysis was performed using morphological and molecular data. Key results The fossil flowers share some but not all the synapomorphies that characterize the Schizomerieae, a tribe within Cunoniaceae. These features include the shallow floral cup, variable number of perianth parts arranged in two whorls, laciniate petals, anthers with a connective extension, and a superior ovary with free styles. The number of perianth parts is doubled and the in situ pollen is tricolporate, with a surface more like that of other Cunoniaceae outside Schizomerieae, such as Davidsonia or Weinmannia. Conclusions An extinct genus of crown-group Cunoniaceae is recognized and placed along the stem lineage leading to Schizomerieae. Extant relatives are typical of tropical to southern-temperate rainforests, and these fossils likely indicate a similarly warm and wet temperate palaeoclimate. The oldest reliable occurrences of the family are fossil pollen and wood from the Upper Cretaceous of the Antarctica and Argentina, whereas in Australia the family first occurs in upper Palaeocene deposits. This discovery demonstrates that the family survived the Cretaceous\u2013Palaeogene boundary event in Patagonia and that diversification of extant lineages in the family was under way by the earliest Cenozoic.", "keyphrases": ["patagonia", "argentina", "fossil flower"]}
{"id": "paleo.005521", "title": "Deciphering the early evolution of echinoderms with Cambrian fossils", "abstract": "Echinoderms are a major group of invertebrate deuterostomes that have been an important component of marine ecosystems throughout the Phanerozoic. Their fossil record extends back to the Cambrian, when several disparate groups appear in different palaeocontinents at about the same time. Many of these early forms exhibit character combinations that differ radically from extant taxa, and thus their anatomy and phylogeny have long been controversial. Deciphering the earliest evolution of echinoderms therefore requires a detailed understanding of the morphology of Cambrian fossils, as well as the selection of an appropriate root and the identification of homologies for use in phylogenetic analysis. Based on the sister\u2010group relationships and ontogeny of modern species and new fossil discoveries, we now know that the first echinoderms were bilaterally symmetrical, represented in the fossil record by Ctenoimbricata and some early ctenocystoids. The next branch in echinoderm phylogeny is represented by the asymmetrical cinctans and solutes, with an echinoderm\u2010type ambulacral system originating in the more crownward of these groups (solutes). The first radial echinoderms are the helicoplacoids, which possess a triradial body plan with three ambulacra radiating from a lateral mouth. Helicocystoids represent the first pentaradial echinoderms and have the mouth facing upwards with five radiating recumbent ambulacra. Pentaradial echinoderms diversified rapidly from the beginning of their history, and the most significant differences between groups are recorded in the construction of the oral area and ambulacra, as well as the nature of their feeding appendages. Taken together, this provides a clear narrative of the early evolution of the echinoderm body plan.", "keyphrases": ["early evolution", "echinoderm", "cambrian fossil"]}
{"id": "10.1017/S0094837300005352", "title": "The Mesozoic marine revolution: evidence from snails, predators and grazers", "abstract": "Tertiary and Recent marine gastropods include in their ranks a complement of mechanically sturdy forms unknown in earlier epochs. Open coiling, planispiral coiling, and umbilici detract from shell sturdiness, and were commoner among Paleozoic and Early Mesozoic gastropods than among younger forms. Strong external sculpture, narrow elongate apertures, and apertural dentition promote resistance to crushing predation and are primarily associated with post-Jurassic mesogastropods, neogastropods, and neritaceans. The ability to remodel the interior of the shell, developed primarily in gastropods with a non-nacreous shell structure, has contributed greatly to the acquisition of these antipredatory features. The substantial increase of snail-shell sturdiness beginning in the Early Cretaceous has accompanied, and was perhaps in response to, the evolution of powerful, relatively small, shell-destroying predators such as teleosts, stomatopods, and decapod crustaceans. A simultaneous intensification of grazing, also involving skeletal destruction, brought with it other fundamental changes in benthic community structure in the Late Mesozoic, including a trend toward infaunalization and the disappearance or environmental restriction of sessile animals which cannot reattach once they are dislodged. The rise and diversification of angiosperms and the animals dependent on them for food coincides with these and other Mesozoic events in the marine benthos and plankton. The new predators and prey which evolved in conjunction with the Mesozoic reorganization persisted through episodes of extinction and biological crisis. Possibly, continental breakup and the wide extent of climatic belts during the Late Mesozoic contributed to the conditions favorable to the evolution of skeleton-destroying consumers. This tendency may have been exaggerated by an increase in shelled food supply resulting from the occupation of new adaptive zones by infaunal bivalves and by shell-inhabiting hermit crabs. Marine communities have not remained in equilibrium over their entire geological history. Biotic revolutions made certain modes of life obsolete and resulted in other adaptive zones becoming newly occupied.", "keyphrases": ["mesozoic marine revolution", "predator", "phanerozoic", "mmr"]}
{"id": "10.1093/nsr/nwz161", "title": "Are hyoliths Palaeozoic lophophorates?", "abstract": "Abstract The phylogenetic position of hyoliths has long been unsettled, with recent discoveries of a tentaculate feeding apparatus (\u2018lophophore\u2019) and fleshy apical extensions from the shell (\u2018pedicle\u2019) suggesting a lophophorate affinity. Here, we describe the first soft parts associated with the feeding apparatus of an orthothecid hyolith, Triplicatella opimus from the Chengjiang biota of South China. The tuft-like arrangement of the tentacles of T. opimus differs from that of hyolithids, suggesting they collected food directly from the substrate. A reassessment of the feeding organ in hyolithids indicates that it does not represent a lophophore and our analysis of the apical structures associated with some orthothecids show that these represent crushed portions of the shell and are not comparable to the brachiopod pedicle. The new information suggests that hyoliths are more likely to be basal members of the lophotrochozoans rather than lophophorates closely linked with the Phylum Brachiopoda.", "keyphrases": ["hyolith", "lophophorate", "phylogenetic position"]}
{"id": "paleo.006782", "title": "In quest for a phylogeny of Mesozoic mammals", "abstract": "We propose a phylogeny of all major groups of Mesozoic mammals based on phylogenetic analyses of 46 taxa and 275 osteological and dental characters, using parsimony methods (Swofford 2000) . Mammalia sensu lato (Mammaliaformes of some authors) are monophyletic. Within mammals, Sinoconodon is the most primitive taxon. Sinoconodon, morganucodontids, docodonts, and Hadrocodium lie outside the mammalian crown group (crown therians + Monotremata) and are, successively, more closely related to the crown group. Within the mammalian crown group, we recognize a fundamental division into australosphenidan (Gondwana) and boreosphenidan (Laurasia) clades, possibly with vicariant geographic distributions during the Jurassic and Early Cretaceous. We provide additional derived characters supporting these two ancient clades, and we present two evolutionary hypotheses as to how the molars of early monotremes could have evolved. We consider two alternative placements of allotherians (haramiyids + multituberculates). The first, supported by strict consensus of most parsimonious trees, suggests that multituberculates (but not other alllotherians) are closely related to a clade including spalacotheriids + crown therians (Trechnotheria as redefined herein). Alternatively, allotherians can be placed outside the mammalian crown group by a constrained search that reflects the traditional emphasis on the uniqueness of the multituberculate dentition. Given our dataset, these alternative topologies differ in tree-length by only ~0.6% of the total tree length; statistical tests show that these positions do not differ significantly from one another. Similarly, there exist two alternative positions of eutriconodonts among Mesozoic mammals, contingent on the placement of other major mammalian clades. Of these, we tentatively favor recognition of a monophyletic Eutriconodonta, nested within the mammalian crown group. We suggest that the \"obtuse-angle symmetrodonts\" are paraphyletic, and that they lack reliable and unambiguous synapomorphies.", "keyphrases": ["phylogeny", "mesozoic mammal", "dental character", "crown therian", "australosphenida"]}
{"id": "10.1086/684289", "title": "Age, Correlation, and Lithostratigraphic Revision of the Upper Cretaceous (Campanian) Judith River Formation in Its Type Area (North-Central Montana), with a Comparison of Low- and High-Accommodation Alluvial Records", "abstract": "Despite long-standing significance in the annals of North American stratigraphy and paleontology, key aspects of the Upper Cretaceous Judith River Formation remain poorly understood. We re-evaluate Judith River stratigraphy and propose new reference sections that both document the range of lithologies present in the type area in north-central Montana and reveal dramatic changes in facies architecture, fossil content, and rock accumulation rates that can be mapped throughout the type area and into the plains of southern Alberta and Saskatchewan. One section spans the basal contact of the Judith River Formation with marine shales of the underlying Claggett Formation. This contact, which lies along the base of the Parkman Sandstone Member of the Judith River Formation, is erosional and consistent with an episode of forced regression, contrary to previous descriptions. A second reference section spans the entire Judith River Formation. This complete section hosts a lithologic discontinuity, herein referred to as the mid-Judith discontinuity, that reflects a regional reorganization of terrestrial and marine depositional systems associated with a turnaround from regressive to transgressive deposition. The mid-Judith discontinuity correlates with the base of three backstepping marine sequences in the eastern sector of the type area and is thus interpreted as the terrestrial expression of a maximum regressive surface. This mid-Judith discontinuity defines the boundary between the new McClelland Ferry and overlying Coal Ridge Members of the Judith River Formation. The shallow marine sandstones that form the backstepping sequences represent the leading edge of the Bearpaw transgression in this region and are formalized as the new Woodhawk Member of the Judith River Formation in a third reference section. New 40Ar/39Ar ages indicate (1) that the mid-Judith discontinuity formed \u223c76.2 Ma, coincident with the onset of the Bearpaw transgression in central Montana; and (2) that the Bearpaw Sea had advanced westward beyond the Judith River type area by \u223c75.2 Ma, on the basis of the dating of a bentonite bed at the base of the Bearpaw Formation. These new ages also provide more confident age control for important vertebrate fossil occurrences in the Judith River Formation. Facies analysis across the mid-Judith discontinuity reveals how alluvial systems respond to regional base-level rise, which is implicit with the increase in rock accumulation rates and marine transgression. With the increase in accommodation signaled by the mid-Judith discontinuity, the alluvial system shifted in dominance from fluvial channel to overbank deposits, with greater tidal influence in channel sands, more hydromorphic and carbonaceous overbank deposits, and a higher frequency of bentonites and skeletal concentrations, suggesting higher preservation rates. These features, along with the appearance of extraformational pebbles above the discontinuity, are consistent with an upstream tectonic explanation for the addition of accommodation.", "keyphrases": ["judith river formation", "montana", "mid-judith discontinuity", "western interior seaway"]}
{"id": "10.1126/science.1236573", "title": "A Paleogenomic Perspective on Evolution and Gene Function: New Insights from Ancient DNA", "abstract": "Background After three decades of research aimed at recovering DNA from preserved remains, the field of ancient DNA is moving rapidly toward the sequencing and analysis of complete paleogenomes. These data provide a means to better understand evolutionary processes through time, including inference of ancient demography and admixture between lineages, as well as adaptive evolution within populations. The increasing scope of paleogenomics. The proportion of sequence reads that are mappable to a reference genome decreases rapidly with evolutionary distance (blue bars). Recent divergence from a living species is therefore key to successful paleogenomic assembly. Fortunately, most species are diverged from a living relative by <50 million years, so it should in principle be possible to generate paleogenomes for a wide taxonomic variety of organisms. Ma, millions of years ago. Advances Key advances enabling a paleogenomic perspective include improvements in DNA extraction and library preparation, as well as methods to enrich ancient libraries for targeted loci. These methods have made it possible to isolate ancient DNA from a far wider range of preservation environments than has been assumed to be attainable, including extending the temporal reach of ancient DNA back to nearly 1 million years. Outlook Although relatively few paleogenomes have been published to date, their number is rising rapidly, and it is increasingly clear that the range of specimens from which paleogenomes could be produced is much larger than has been assumed previously. As more data become available, including genomic data from living organisms, the capacity to use paleogenomic data to infer evolutionary change through time will continue to expand, particularly with respect to the evolution of populations and the link between genotype and phenotype. The Present of the Past A major goal of evolutionary biology is to understand the process of speciation and the changes that have accompanied and shaped the current distribution of species. Paleogenomics directly addresses these questions through the use of ancient DNA. Shapiro and Hofreiter (10.1126/science.1236573) review the origins and growth of this field and explain how challenges owing to the limited amount of DNA available for analysis and the possibility of contamination by modern material have been overcome. The publication of partial and complete paleogenomes within the last few years has reinvigorated research in ancient DNA. No longer limited to short fragments of mitochondrial DNA, inference of evolutionary processes through time can now be investigated from genome-wide data sampled as far back as 700,000 years. Tremendous insights have been made, in particular regarding the hominin lineage. With rare exception, however, a paleogenomic perspective has been mired by the quality and quantity of recoverable DNA. Though conceptually simple, extracting ancient DNA remains challenging, and sequencing ancient genomes to high coverage remains prohibitively expensive for most laboratories. Still, with improvements in DNA isolation and declining sequencing costs, the taxonomic and geographic purview of paleogenomics is expanding at a rapid pace. With improved capacity to screen large numbers of samples for those with high proportions of endogenous ancient DNA, paleogenomics is poised to become a key technology to better understand recent evolutionary events.", "keyphrases": ["paleogenomic perspective", "ancient dna", "evolutionary process"]}
{"id": "10.1017/S1464793103006134", "title": "At the feet of the dinosaurs: the early history and radiation of lizards", "abstract": "Lizards, snakes and amphisbaenians together constitute the Squamata, the largest and most diverse group of living reptiles. Despite their current success, the early squamate fossil record is extremely patchy. The last major survey of squamate palaeontology and evolution was published 20 years ago. Since then, there have been changes in systematic theory and methodology, as well as a steady trickle of new fossil finds. This review examines our current understanding of the first 150 million years of squamate evolution in the light of the new data and changing ideas. Contrary to previous reports, no squamate fossils are currently documented before the Jurasis. Nonetheless, indirect evidence predicts that squamates had evolved by at least the middle Triassic, and diversified into existing major lineages before the end of this period. There is thus a major gap in the squamate record at a time when key morphological features were evolving. With the exception of fragmentary remains from Africa and India, Jurassic squamates are known only from localities in northern continents (Laurasia). The situation improves in the Early Cretaceous, but the southern (Gondwanan) record remains extremely poor. This constrains palaeobiogeographic discussion and makes it difficult to predict centres of origin for major squamate clades on the basis of fossil evidence alone. Preliminary mapping of morphological characters onto a consensus tree demonstrates stages in the sequence of acquisition for some characters of the skull and postcranial skeleton, but many crucial stages \u2013 most notably those relating to the acquisition of squamate skull kinesis \u2013 remain unclear.", "keyphrases": ["lizard", "amphisbaenian", "squamate", "lepidosauria"]}
{"id": "10.1111/joa.12396", "title": "The ear region of earliest known elephant relatives: new light on the ancestral morphotype of proboscideans and afrotherians", "abstract": "One of the last major clades of placental mammals recognized was the Afrotheria, which comprises all main endemic African mammals. This group includes the ungulate\u2010like paenungulates, and among them the elephant order Proboscidea. Among afrotherians, the petrosal anatomy remains especially poorly known in Proboscidea. We provide here the first comparative CT scan study of the ear region of the two earliest known proboscideans (and paenungulates), Eritherium and Phosphatherium, from the mid Palaeocene and early Eocene of Morocco. It is helpful to characterize the ancestral morphotype of Proboscidea to understand petrosal evolution within proboscideans and afrotherians. The petrosal structure of these two taxa shows several differences. Eritherium is more primitive than Phosphatherium and closer to the basal paenungulate Ocepeia in several traits (inflated tegmen tympani, very deep fossa subarcuata and ossified canal for ramus superior of stapedial artery). Phosphatherium, however, retains plesiomorphies such as a true crus commune secundaria. A cladistic analysis of petrosal traits of Eritherium and Phosphatherium among Proboscidea results in a single tree with a low level of homoplasy in which Eritherium, Phosphatherium and Numidotherium are basal. This contrasts with previous phylogenetic studies showing homoplasy in petrosal evolution among Tethytheria. It suggests that evolutionary modalities of petrosal characters differ with the taxonomic level among Afrotheria: noticeable convergences occurred among the paenungulate orders, whereas little homoplasy seems to have occurred at intra\u2010ordinal level in orders such as Proboscidea. Most petrosal features of both Eritherium and Phosphatherium are primitive. The ancestral petrosal morphotype of Proboscidea was not specialized but was close to the generalized condition of paenungulates, afrotherians, and even eutherians. This is consistent with cranial and dental characters of Eritherium, suggesting that the ancestral morphotypes of the different paenungulate orders were close to each other. Specializations occurred rapidly after the ordinal radiation of Paenungulata.", "keyphrases": ["ear region", "ancestral morphotype", "proboscidean"]}
{"id": "10.1146/annurev.earth.35.031306.140104", "title": "Finite Element Analysis and Understanding the Biomechanics and Evolution of Living and Fossil Organisms", "abstract": "AbstractFinite element analysis (FEA) is a technique that reconstructs stress, strain, and deformation in a digital structure. Although commonplace in engineering and orthopedic science for more than 30 years, only recently has it begun to be adopted in the zoological and paleontological sciences to address questions of organismal morphology, function, and evolution. Current research tends to focus on either deductive studies that assume a close relationship between form and function or inductive studies that aim to test this relationship, although explicit hypothesis-testing bridges these two standpoints. Validation studies have shown congruence between in vivo or in vitro strain and FE-inferred strain. Future validation work on a broad range of taxa will assist in phylogenetically bracketing our extinct animal FE-models to increase confidence in our input parameters, although currently, FEA has much potential in addressing questions of form-function relationships, providing appropriate questions are ask...", "keyphrases": ["fea", "strain", "deformation", "finite element analysis", "load"]}
{"id": "paleo.010601", "title": "Human Remains from the Pleistocene-Holocene Transition of Southwest China Suggest a Complex Evolutionary History for East Asians", "abstract": "Background Later Pleistocene human evolution in East Asia remains poorly understood owing to a scarcity of well described, reliably classified and accurately dated fossils. Southwest China has been identified from genetic research as a hotspot of human diversity, containing ancient mtDNA and Y-DNA lineages, and has yielded a number of human remains thought to derive from Pleistocene deposits. We have prepared, reconstructed, described and dated a new partial skull from a consolidated sediment block collected in 1979 from the site of Longlin Cave (Guangxi Province). We also undertook new excavations at Maludong (Yunnan Province) to clarify the stratigraphy and dating of a large sample of mostly undescribed human remains from the site. Methodology/Principal Findings We undertook a detailed comparison of cranial, including a virtual endocast for the Maludong calotte, mandibular and dental remains from these two localities. Both samples probably derive from the same population, exhibiting an unusual mixture of modern human traits, characters probably plesiomorphic for later Homo, and some unusual features. We dated charcoal with AMS radiocarbon dating and speleothem with the Uranium-series technique and the results show both samples to be from the Pleistocene-Holocene transition: \u223c14.3-11.5 ka. Conclusions/Significance Our analysis suggests two plausible explanations for the morphology sampled at Longlin Cave and Maludong. First, it may represent a late-surviving archaic population, perhaps paralleling the situation seen in North Africa as indicated by remains from Dar-es-Soltane and Temara, and maybe also in southern China at Zhirendong. Alternatively, East Asia may have been colonised during multiple waves during the Pleistocene, with the Longlin-Maludong morphology possibly reflecting deep population substructure in Africa prior to modern humans dispersing into Eurasia.", "keyphrases": ["pleistocene-holocene transition", "southwest china", "human remain", "hominin"]}
{"id": "paleo.010498", "title": "Hunting the Extinct Steppe Bison (Bison priscus) Mitochondrial Genome in the Trois-Fr\u00e8res Paleolithic Painted Cave", "abstract": "Despite the abundance of fossil remains for the extinct steppe bison (Bison priscus), an animal that was painted and engraved in numerous European Paleolithic caves, a complete mitochondrial genome sequence has never been obtained for this species. In the present study we collected bone samples from a sector of the Trois-Fr\u00e8res Paleolithic cave (Ari\u00e8ge, France) that formerly functioned as a pitfall and was sealed before the end of the Pleistocene. Screening the DNA content of the samples collected from the ground surface revealed their contamination by Bos DNA. However, a 19,000-year-old rib collected on a rock apart the pathway delineated for modern visitors was devoid of such contaminants and reproducibly yielded Bison priscus DNA. High-throughput shotgun sequencing combined with conventional PCR analysis of the rib DNA extract enabled to reconstruct a complete mitochondrial genome sequence of 16,318 bp for the extinct steppe bison with a 10.4-fold coverage. Phylogenetic analyses robustly established the position of the Bison priscus mitochondrial genome as basal to the clade delineated by the genomes of the modern American Bison bison. The extinct steppe bison sequence, which exhibits 93 specific polymorphisms as compared to the published Bison bison mitochondrial genomes, provides an additional resource for the study of Bovinae specimens. Moreover this study of ancient DNA delineates a new research pathway for the analysis of the Magdalenian Trois-Fr\u00e8res cave.", "keyphrases": ["bison priscus", "mitochondrial genome", "present study"]}
{"id": "10.1126/sciadv.aax1874", "title": "Simulation of Eocene extreme warmth and high climate sensitivity through cloud feedbacks", "abstract": "A state-of-the-art climate model successfully simulates Early Eocene extreme warmth and high climate sensitivity during the PETM. The Early Eocene, a period of elevated atmospheric CO2 (>1000 ppmv), is considered an analog for future climate. Previous modeling attempts have been unable to reproduce major features of Eocene climate indicated by proxy data without substantial modification to the model physics. Here, we present simulations using a state-of-the-art climate model forced by proxy-estimated CO2 levels that capture the extreme surface warmth and reduced latitudinal temperature gradient of the Early Eocene and the warming of the Paleocene-Eocene Thermal Maximum. Our simulations exhibit increasing equilibrium climate sensitivity with warming and suggest an Eocene sensitivity of more than 6.6\u00b0C, much greater than the present-day value (4.2\u00b0C). This higher climate sensitivity is mainly attributable to the shortwave cloud feedback, which is linked primarily to cloud microphysical processes. Our findings highlight the role of small-scale cloud processes in determining large-scale climate changes and suggest a potential increase in climate sensitivity with future warming.", "keyphrases": ["extreme warmth", "high climate sensitivity", "simulation"]}
{"id": "paleo.000977", "title": "Fossilization causes organisms to appear erroneously primitive by distorting evolutionary trees", "abstract": "Fossils are vital for calibrating rates of molecular and morphological change through geological time, and are the only direct source of data documenting macroevolutionary transitions. Many evolutionary studies therefore require the robust phylogenetic placement of extinct organisms. Here, we demonstrate that the inevitable bias of the fossil record to preserve just hard, skeletal morphology systemically distorts phylogeny. Removal of soft part characters from 78 modern vertebrate and invertebrate morphological datasets resulted in significant changes to phylogenetic signal; it caused individual taxa to drift from their original position, predominately downward toward the root of their respective trees. This last bias could systematically inflate evolutionary rates inferred from molecular data because first fossil occurrences will not be recognised as such. Stem-ward slippage, whereby fundamental taphonomic biases cause fossils to be interpreted as erroneously primitive, is therefore a ubiquitous problem for all biologists attempting to infer macroevolutionary rates or sequences.", "keyphrases": ["tree", "fossilization", "taphonomic process"]}
{"id": "10.1080/02724634.1988.10011708", "title": "Definition, diagnosis, and origin of Mammalia", "abstract": "ABSTRACT Mammalia is defined by its ancestry as the taxon originating with the most recent common ancestor of extant Monotremata and Theria. To diagnose Mammalia as so defined, 176 character transformations in the skull and postcranial skeleton, distributed among Placentalia, Marsupialia, Multituberculata, Monotremata, Morganucodontidae, Tritylodontidae, and Exaeretodon, were polarized, scored, and subjected to PAUP. Only one most parsimonious tree was identified (BL = 190, CI = 0.926): (Exaeretodon (Tritylodontidae (Morganucodontidae (Monotremata (Multituberculata (Marsupialia, Placentalia)))))). Thirty-seven osteological synapomorphies diagnose Mammalia. Triassic and Early Jurassic taxa commonly referred to as mammals, including Morganucodontidae, Kuehneotheriidae, and Haramiyidae, were found to lie outside of Mammalia. These fossils document that the mammalian lineage had diverged from other known synapsid lineages by the Norian (Late Triassic). However, the earliest evidence that Monotremata and Theri...", "keyphrases": ["mammalia", "tritylodontidae", "definition", "cynodont"]}
{"id": "paleo.006700", "title": "Late Cretaceous mega-, meso-, and microfloras from Lower Silesia", "abstract": "Late Cretaceous plants from the North Sudetic Basin (Lower Silesia, south-western Poland) are reviewed on the basis of megaflora from 17 localities (270 identifiable specimens), mesoflora from two localities, and microflora from four localities. Major sites are Rakowice Ma\u0142e and Boles\u0142awiec. Eight megafloral assemblages are distinguished (Assemblage 1, Turonian; Assemblages 2, 3, lower\u2013middle Coniacian; Assemblages 4, 5, upper Coniacian?\u2013lower Santonian?; Assemblages 6\u20138, lower\u2013middle Santonian); the bulk of the palaeoflora is from Assemblages 4\u20136 and 8. Megaflora consists of 29 taxa (6 ferns, 4 conifers, and 19 angiosperms). Geinitzia reichenbachii the most common species. westerhausianum (Richter, Halamski and Kva\u010dek comb. nov. is a trifoliolate leaf re-interpreted as a representative of Fagales. Three species of Dewalquea are distinguished: Dewalquea haldemiana , Dewalquea insignis , and Dewalquea aff. gelindenensis . Platanites willigeri Halamski and Kva\u010dek sp. nov. is characterised by trifoliolate leaves, the median leaflet of which is ovate, unlobed, with a serrate margin, and cuneate base. Palaeocommunities inferred from the megafossil record include: a back swamp forest dominated by Geinitzia , with abundant ferns; a Dryophyllum -dominated riparian forest; a forest with Dewalquea and Platanites willigeri possibly located in the marginal part of the alluvial plain; dunes with D. haldemiana and Konijnenburgia ; a fern savanna with patches of Pinus woodlands. Palynoassemblage A from the Nowogrodziec Member, studied mostly at Rakowice Ma\u0142e and \u017belisz\u00f3w, consists of 126 taxa, including 105 terrestrial palynomorphs (54 bryophyte, lycophyte, and pteridophyte spores, 16 gymnosperms, 35 angiosperms). The mega- and mesofossil records are dominated by angiosperms; the palynoassemblages are dominated by ferns. Palaeocommunities represented solely by the microfossil record are halophytic (with Frenelopsis and unconfirmed presence of Nypa ) and pioneer vegetation. Palaeocommunities are intermediate in general character between those pre-dating the Cretaceous Terrestrial Revolution and modern, angiosperm- dominated vegetation. In comparison to older plant assemblages from contiguous areas laurophylls are much rarer; this might correspond to a real phenomenon of exclusion of lauroids from Santonian riparian forests. The studied assemblage is more similar to younger palaeofloras than to older ones; this might be interpreted as stabilisation of communities after a period of pronounced change related to the rise to dominance of the angiosperms. In contrast to widespread endemism among vertebrates of the European Archipelago, the plant cover consists mostly of species that are widely distributed.", "keyphrases": ["microflora", "lower silesia", "santonian"]}
{"id": "10.1080/03115518.2013.748482", "title": "Lark Quarry revisited: a critique of methods used to identify a large dinosaurian track-maker in the Winton Formation (Albian\u2013Cenomanian), western Queensland, Australia", "abstract": "Thulborn, R.A., 2013. Lark Quarry revisited: a critique of methods used to identify a large dinosaurian track-maker in the Winton Formation (Albian\u2013Cenomanian), western Queensland, Australia. Alcheringa, http://dx.doi.org/10.1080/03115518.2013.748482 A remarkable assemblage of dinosaur tracks in the Winton Formation (Albian\u2013Cenomanian) at Lark Quarry, a site in western Queensland, Australia, has long been regarded as evidence of a dinosaurian stampede. However, one recently published study has claimed that existing interpretation of Lark Quarry is incorrect because the largest track-maker at the site was misidentified and could not have played a pivotal role in precipitating a stampede. That recent study has identified the largest track-maker as an ornithopod (bipedal plant-eating dinosaur) similar or identical to Muttaburrasaurus and not, as formerly supposed, a theropod (predaceous dinosaur) resembling Allosaurus. Those iconoclastic claims are examined here and are shown to be groundless: they are based partly on misconceptions and partly on fabricated data that have been assessed uncritically using quantitative measures of questionable significance. Such ill-founded claims do not reveal any substantial flaw in the existing interpretation of the Lark Quarry dinosaur tracks.", "keyphrases": ["large dinosaurian track-maker", "winton formation", "western queensland"]}
{"id": "10.1111/j.1469-185X.2011.00178.x", "title": "A phylogeny of Cenozoic macroperforate planktonic foraminifera from fossil data", "abstract": "We present a complete phylogeny of macroperforate planktonic foraminifer species of the Cenozoic Era (\u223c65 million years ago to present). The phylogeny is developed from a large body of palaeontological work that details the evolutionary relationships and stratigraphic (time) distributions of species\u2010level taxa identified from morphology (\u2018morphospecies\u2019). Morphospecies are assigned to morphogroups and ecogroups depending on test morphology and inferred habitat, respectively. Because gradual evolution is well documented in this clade, we have identified many instances of morphospecies intergrading over time, allowing us to eliminate \u2018pseudospeciation\u2019 and \u2018pseudoextinction\u2019 from the record and thereby permit the construction of a more natural phylogeny based on inferred biological lineages. Each cladogenetic event is determined as either budding or bifurcating depending on the pattern of morphological change at the time of branching. This lineage phylogeny provides palaeontologically calibrated ages for each divergence that are entirely independent of molecular data. The tree provides a model system for macroevolutionary studies in the fossil record addressing questions of speciation, extinction, and rates and patterns of evolution.", "keyphrases": ["phylogeny", "cenozoic", "planktonic foraminifera", "morphospecie"]}
{"id": "10.1017/pab.2019.43", "title": "Body size, sampling completeness, and extinction risk in the marine fossil record", "abstract": "Abstract. Larger body size has long been assumed to correlate with greater risk of extinction, helping to shape body-size distributions across the tree of life, but a lack of comprehensive size data for fossil taxa has left this hypothesis untested for most higher taxa across the vast majority of evolutionary time. Here we assess the relationship between body size and extinction using a data set comprising the body sizes, stratigraphic ranges, and occurrence patterns of 9408 genera of fossil marine animals spanning eight Linnaean classes across the past 485 Myr. We find that preferential extinction of smaller-bodied genera within classes is substantially more common than expected due to chance and that there is little evidence for preferential extinction of larger-bodied genera. Using a capture\u2013mark\u2013recapture analysis, we find that this size bias of extinction persists even after accounting for a pervasive bias against the sampling of smaller-bodied genera within classes. The size bias in extinction also persists after including geographic range as an additional predictor of extinction, indicating that correlation between body size and geographic range does not provide a simple explanation for the association between size and extinction. Regardless of the underlying causes, the preferential extinction of smaller-bodied genera across many higher taxa and most of geologic time indicates that the selective loss of large-bodied animals is the exception, rather than the rule, in the evolution of marine animals.", "keyphrases": ["extinction risk", "marine animal", "class", "body size"]}
{"id": "paleo.004384", "title": "Brachiopods hitching a ride: an early case of commensalism in the middle Cambrian Burgess Shale", "abstract": "Ecological interactions, including symbiotic associations such as mutualism, parasitism and commensalism are crucial factors in generating evolutionary novelties and strategies. Direct examples of species interactions in the fossil record generally involve organisms attached to sessile organisms in an epibiont or macroboring relationship. Here we provide support for an intimate ecological association between a calcareous brachiopod (Nisusia) and the stem group mollusc Wiwaxia from the Burgess Shale. Brachiopod specimens are fixed to Wiwaxia scleritomes, the latter showing no signs of decay and disarticulation, suggesting a live association. We interpret this association as the oldest unambiguous example of a facultative ectosymbiosis between a sessile organism and a mobile benthic animal in the fossil record. The potential evolutionary advantage of this association is discussed, brachiopods benefiting from ease of attachment, increased food supply, avoidance of turbid benthic conditions, biofoul and possible protection from predators, suggesting commensalism (benefiting the symbiont with no impact for the host). While Cambrian brachiopods are relatively common epibionts, in particular on sponges, the association of Nisusia with the motile Wiwaxia is rare for a brachiopod species, fossil or living, and suggests that symbiotic associations were already well established and diversified by the ''middle'' (Series 3, Stage 5) Cambrian.\nymbiosis in a broad sense refers to the intimate physical association between two organisms, commonly one species (symbiont) living with a host species 1 , associations that are notoriously difficult to detect in the fossil record. Seen as a crucial factor in the evolution of organisms 2 , symbiotic relationships are displayed by millions of modern day organisms canvasing the terrestrial and marine realms. Associations can take a number of forms, generally categorized based on the impact incurred by the host 3 , including parasitism (negative impact on the host), mutualism (positive impacts for both host and symbiont) and commensalism (no direct impact for host but positive for the symbiont). Symbiosis is a poorly studied aspect of the fossil record, owing largely to taphonomic biases that inconveniently inhibit preservation of direct interaction between two or more organisms in life. Despite the difficulties, various forms of symbiosis have been identified in the fossil record, principally from Ordovician and younger strata and predominantly dealing with epibiont and macroboring organisms 4 .\nBrachiopods, one of the dominant filter feeders of the Palaeozoic, frequently play both roles, acting as symbionts and as hosts. Attaching themselves to various sessile organisms for support 5 and having a range of organisms living on 6,7 and to some extent inside their shell 8, 9 . Brachiopods generally attach to hard substrates by means of a pedicle, this includes substrates such as, sponges 10 , algae 5 , other brachiopods 11 , disarticulated skeletal elements 12 , an attachment strategy that has not significantly changed since the phylum arose in the Cambrian 13 . Brachiopods have, in rare instances, been documented attached to the spines of live echinoids from the Carboniferous (Pennsylvanian) echinoderm Lagersta \u00a8tte in the Winchell Formation of Texas 14 . Exceptionally preserved in situ records of Cambrian brachiopods attached to other organisms have been reported from Burgess Shale-type deposits 5, 10 , and such associations generally involve other sessile organisms such as sponges and algae. Enigmatic shells (possibly brachiopods) attached to the disk of the eldoniid Rotadiscus 15 , have also been reported, but it is not clear whether eldoniids had a semi-vagrant lifestyle 16 or were entirely sessile 15 . A couple of occurrences of brachiopods possibly attached to unambiguous vagile organisms have also been noted from the Burgess Shale, including on the arthropod Sidneyia inexpectans 17 and on an isolated sclerite of the stem group mollusk Wiwaxia corrugata 18 . However, in both cases the possible attachments occurred on disarticulated body elements suggesting the hosts represented molts or carcasses and not live animals. One other example involved a complete and", "keyphrases": ["commensalism", "burgess shale", "ecological interaction", "brachiopod", "cambrian lagerst\u00e4tten"]}
{"id": "paleo.008942", "title": "Subsequent biotic crises delayed marine recovery following the late Permian mass extinction event in northern Italy", "abstract": "The late Permian mass extinction event was the largest biotic crisis of the Phanerozoic and has the longest recovery interval of any extinction event. It has been hypothesised that subsequent carbon isotope perturbations during the Early Triassic are associated with biotic crises that impeded benthic recovery. We test this hypothesis by undertaking the highest-resolution study yet made of the rock and fossil records of the entire Werfen Formation, Italy. Here, we show that elevated extinction rates were recorded not only in the Dienerian, as previously recognised, but also around the Smithian/Spathian boundary. Functional richness increases across the Smithian/Spathian boundary associated with elevated origination rates in the lower Spathian. The taxonomic and functional composition of benthic faunas only recorded two significant changes: (1) reduced heterogeneity in the Dienerian, and (2) and a faunal turnover across the Smithian/Spathian boundary. The elevated extinctions and compositional shifts in the Dienerian and across the Smithian/Spathian boundary are associated with a negative and positive isotope excursion, respectively, which supports the hypothesis that subsequent biotic crises are associated with carbon isotope shifts. The Spathian fauna represents a more advanced ecological state, not recognised in the previous members of the Werfen Formation, with increased habitat differentiation, a shift in the dominant modes of life, appearance of stenohaline taxa and the occupation of the erect and infaunal tiers. In addition to subsequent biotic crises delaying the recovery, therefore, persistent environmental stress limited the ecological complexity of benthic recovery prior to the Spathian.", "keyphrases": ["recovery", "mass extinction event", "biotic crisis", "early triassic"]}
{"id": "paleo.000384", "title": "Otoliths in situ from Sarmatian (Middle Miocene) fishes of the Paratethys. Part III: tales from the cradle of the Ponto-Caspian gobies", "abstract": "Articulated fossil fish skeletons with otoliths in situ provide a unique opportunity to link these two, otherwise independent data sets of skeletons and otoliths. They provide calibration points for otoliths also adding important information for the evolutionary interpretation of fishes. Here, we review nine articulated skeletons of gobies from the early Sarmatian of Dolje, Croatia, and Belgrade, Serbia, which were previously regarded as members of a single gobiid and a callionymid species. We found them to represent five different gobiid species belonging to five different genera, four of which are related to extant endemic Ponto-Caspian gobiid lineages. The species are: Aphia macrophthalma n.sp., Proneogobius n.gen. pullus (the only previously recognized species), Protobenthophilus n.gen. squamatus n.sp., Economidichthys triangularis (a species first described based on otoliths) and Hesperichthys n.gen. reductus n.sp. Five specimens contained otoliths in situ and a sixth shows imprints of otoliths which unfortunately must have been lost in the past, probably during preparation of the fossil. Together, they represent all five species recognized by skeletons, and three are linked to otolith-based species. Isolated otoliths have been reviewed from a variety of collections from Sarmatian strata in Austria, Bulgaria, Czechia, Romania and Slovakia resulting in the description of five new otolith-based species: Benthophilus? ovisulcus n.sp., Benthophilus styriacus n.sp., Protobenthophilus strashimirovi n.sp., Economidichthys altidorsalis n.sp. and Knipowitschia bulgarica n.sp. Our review demonstrates that all major endemic Ponto-Caspian gobiid lineages were already present during Sarmatian times, thereby pushing back their origin by approximately 5-10 myr in comparison to previously published dates for dichotomies. In our assessment, the origination of these lineages is linked to the early stage of separation of the Paratethys from the world oceans and the ecological changes that occurred during that time. These geological events parallel a dramatic increase in gobiid radiation and speciation, giving rise to many lineages, not all of which have persisted until today.", "keyphrases": ["sarmatian", "paratethys", "otolith"]}
{"id": "10.1666/06073.1", "title": "Intrinsic versus extrinsic biases in the fossil record: contrasting the fossil record of echinoids in the Triassic and early Jurassic using sampling data, phylogenetic analysis, and molecular clocks", "abstract": "Abstract Four independent lines of evidence, (1) the quality of specimen preservation, (2) taxonomic collection curves, (3) molecular divergence estimates, and (4) ghost lineage analysis of a genus-level cladogram, point to echinoids having a much poorer fossil record in the Triassic than in the Lower Jurassic. Furthermore, preservational differences between Triassic and Lower Jurassic echinoids have remained a consistent feature over 160 years of discovery. Differences exist in how effectively paleontologists have collected the fauna from available outcrops in the Triassic and Lower Jurassic. Collection curves suggest that rocks have been more efficiently searched for their fossils in Europe than elsewhere in the world, and that Lower Jurassic faunas are better sampled from available outcrop than Triassic faunas. The discovery of Triassic taxa has quickened in pace over the past 4 decades (though largely driven by a single Lagerst\u00e4tte\u2014the St. Cassian beds) while discoveries of new taxa from the Lower Jurassic have slowed. Molecular analysis of extant families and ghost lineage analysis of Triassic and Lower Jurassic genera both point to poorer sampling of Triassic faunas. This difference in the quality of the fossil record may be partially explained by differences in rock outcrop area, as marine sedimentary rocks are much less common in the Triassic than in the Lower Jurassic. However, improving biomechanical design of the echinoid test over this critical time interval was probably as important, and better explains observed preservational trends. Changes in the quality of the echinoid fossil record were thus driven as much by intrinsic biological factors as by sampling patterns.", "keyphrases": ["echinoid", "triassic", "phylogenetic analysis"]}
{"id": "paleo.001093", "title": "A new scyphozoan from the Cambrian Fortunian Stage of South China", "abstract": "Animals with radial symmetry are abundant in the Cambrian Fortunian Stage of South China, but with relatively low diversity: representatives include Olivooides, Quadrapyrgites, carinachitiids, hexangulaconulariids and Pseudooides. Here, we report a new radial animal, Qinscyphus necopinus gen. et sp. nov., from the Fortunian small shelly fauna of southern Shaanxi Province, South China. Qinscyphus necopinus has a cup\u2010shaped profile, with slightly raised annuli and five groups of triangular thickenings in pentaradial symmetry. This organism has a comparable morphology to, and thus a close affinity with, Olivooides and Quadrapyrgites, and is interpreted as a coronate scyphozoan. This discovery adds a new crown\u2010group cnidarian to the Cambrian Explosion.", "keyphrases": ["scyphozoan", "cambrian fortunian stage", "south china"]}
{"id": "paleo.008323", "title": "Ecomorphological diversifications of Mesozoic marine reptiles: the roles of ecological opportunity and extinction", "abstract": "Mesozoic marine ecosystems were dominated by several clades of reptiles, including sauropterygians, ichthyosaurs, crocodylomorphs, turtles, and mosasaurs, that repeatedly invaded ocean ecosystems. Previous research has shown that marine reptiles achieved great taxonomic diversity in the Middle Triassic, as they broadly diversified into many feeding modes in the aftermath of the Permo-Triassic mass extinction, but it is not known whether this initial phase of evolution was exceptional in the context of the entire Mesozoic. Here, we use a broad array of disparity, morphospace, and comparative phylogenetic analyses to test this. Metrics of ecomorphology, including functional disparity in the jaws and dentition and skull-size diversity, show that the Middle to early Late Triassic represented a time of pronounced phenotypic diversification in marine reptile evolution. Following the Late Triassic extinctions, diversity recovered, but disparity did not, and it took over 100 Myr for comparable variation to recover in the Campanian and Maastrichtian. Jurassic marine reptiles generally failed to radiate into vacated functional roles. The signatures of adaptive radiation are not seen in all marine reptile groups. Clades that diversified during the Triassic biotic recovery, the sauropterygians and ichthyosauromorphs, do show early diversifications, early high disparity, and early burst, while less support for these models is found in thalattosuchian crocodylomorphs and mosasaurs. Overall, the Triassic represented a special interval in marine reptile evolution, as a number of groups radiated into new adaptive zones.", "keyphrases": ["diversification", "marine reptile", "reptile", "ecological opportunity", "ecomorphological diversification"]}
{"id": "10.1017/S0022336000028006", "title": "An elasmobranch assemblage from the terrestrial-marine transitional Lethbridge Coal Zone (Dinosaur Park Formation: Upper Campanian), Alberta, Canada", "abstract": "The change in depositional environments observed in the Cretaceous (Upper Campanian) strata in the region of Dinosaur Provincial Park, Alberta, from the proximal coastal plain deposits of the Oldman Formation to the lowland coastal plain deposits of the Dinosaur Park Formation, reveals an associated change in faunal composition. An assemblage collected from a microvertebrate site in the paralic deposits of the Lethbridge Coal Zone (uppermost Dinosaur Park Formation) reflects an increasing marine influence. Elasmobranch (sharks and rays) remains are the most abundant, both in terms of number of overall taxa and number of elements, and they are the best-preserved specimens. However, several brackish-water-tolerant osteichthyan taxa, and four reptile taxa (two marine and two terrestrial), were also recovered, although they exhibited evidence of extensive taphonomic reworking. The elasmobranch fauna collected from the Dinosaur Park locality is uncommon for vertebrate microfossil assemblages in the Dinosaur Park Formation of Alberta and in equivalent beds in Montana. Seven of the 10 taxa collected from this site [Cretorectolobus olsoni Case, 1978; Eucrossorhinus microcuspidatus Case, 1978; Odontaspis aculeatus (Cappetta and Case, 1975); Archaeolamna kopingensis judithensis Siverson, 1992; Protoplatyrhina renae Case, 1978; Ischyrhiza mira Leidy, 1856; and Ptychotrygon blainensis Case, 1978] are recorded for the first time from the uppermost section of the Judith River Group in Alberta; Carcharias steineri (Case, 1987), represents the first occurrence within the upper Judith River Group from either Alberta or Montana.", "keyphrases": ["lethbridge coal zone", "dinosaur park formation", "upper campanian"]}
{"id": "paleo.003543", "title": "Estimating dispersal and evolutionary dynamics in diploporan blastozoans (Echinodermata) across the great Ordovician biodiversification event", "abstract": "Echinoderms make up a substantial component of Ordovician marine invertebrates, yet their speciation and dispersal history as inferred within a rigorous phylogenetic and statistical framework is lacking. We use biogeographic stochastic mapping (BSM; implemented in the R package BioGeoBEARS) to infer ancestral area relationships and the number and type of dispersal events through the Ordovician for diploporan blastozoans and related species. The BSM analysis was divided into three time slices to analyze how dispersal paths changed before and during the great Ordovician biodiversification event (GOBE) and within the Late Ordovician mass extinction intervals. The best-fit biogeographic model incorporated jump dispersal, indicating this was an important speciation strategy. Reconstructed areas within the phylogeny indicate the first diploporan blastozoans likely originated within Baltica or Gondwana. Dispersal, jump dispersal, and sympatry dominated the BSM inference through the Ordovician, while dispersal paths varied in time. Long-distance dispersal events in the Early Ordovician indicate distance was not a significant predictor of dispersal, whereas increased dispersal events between Baltica and Laurentia are apparent during the GOBE, indicating these areas were important to blastozoan speciation. During the Late Ordovician, there is an increase in dispersal events among all paleocontinents. The drivers of dispersal are attributed to oceanic and epicontinental currents. Speciation events plotted against geochemical data indicate that blastozoans may not have responded to climate cooling events and other geochemical perturbations, but additional data will continue to shed light on the drivers of early Paleozoic blastozoan speciation and dispersal patterns.", "keyphrases": ["dispersal", "ordovician biodiversification event", "phylogeny"]}
{"id": "paleo.006040", "title": "Dinosaur tracks from the Langenberg Quarry (Late Jurassic, Germany) reconstructed with historical photogrammetry: Evidence for large theropods soon after insular dwarfism", "abstract": "Here we describe dinosaur tracks from the Langenberg Quarry near Goslar (Lower Saxony) that represent the first footprints from the Late Jurassic of Germany discovered outside the Wiehen Mountains. The footprints are preserved in Kimmeridgian marginal marine carbonates. They vary in length from 36 to 47 cm and were made by theropod dinosaurs. The original tracksite with 20 footprints was destroyed by quarrying soon after its discovery in 2003. Only the five best defined footprints were excavated. Based on scanned-in analog photographs which were taken during the excavation, a three-dimensional (3-D) model of the original tracksite was generated by applying historical photogrammetry. The resulting model is accurate enough to allow a detailed description of the original tracksite. Different preservation types result from changing substrate properties and include both well-defined footprints and deeply impressed footprints with elongated heel and variably defined digit impressions. The tracksite was discovered stratigraphically close to the bone accumulation of the dwarfed sauropod dinosaur Europasaurus holgeri and probably records a sea level fall along with a faunal interchange, which would likely have eliminated the resident dwarf island fauna. The two largest and best preserved footprints differ from most other Late Jurassic theropod footprints in their great width. Two different trackmaker species might have been present at the site. Several hypotheses presented in a recent paper on Late Jurassic dinosaur tracks from the Wiehen Mountains by Diedrich (2011b) are commented upon herein.", "keyphrases": ["late jurassic", "historical photogrammetry", "faunal interchange", "dinosaur track"]}
{"id": "paleo.004658", "title": "Spatial point pattern analysis of traces (SPPAT): An approach for visualizing and quantifying site-selectivity patterns of drilling predators", "abstract": "Site-selectivity analysis of drilling predation traces may provide useful behavioral information concerning a predator interacting with its prey. However, traditional approaches exclude some spatial information (i.e., oversimplified trace position) and are dependent on the scale of analysis (e.g., arbitrary grid system used to divide the prey skeleton into sectors). Here we introduce the spatial point pattern analysis of traces (SPPAT), an approach for visualizing and quantifying the distribution of traces on shelled invertebrate prey, which includes improved collection of spatial information inherent to drillhole location (morphometric-based estimation), improved visualization of spatial trends (kernel density and hotspot mapping), and distance-based statistics for hypothesis testing (K-, L-, and pair correlation functions). We illustrate the SPPAT approach through case studies of fossil samples, modern beach-collected samples, and laboratory feeding trials of naticid gastropod predation on bivalve prey. Overall results show that kernel density and hotspot maps enable visualization of subtle variations in regions of the shell with higher density of predation traces, which can be combined with the maximum clustering distance metric to generate hypotheses on predatory behavior and anti-predatory responses of prey across time and geographic space. Distance-based statistics also capture the major features in the distribution of traces across the prey skeleton, including aggregated and segregated clusters, likely associated with different combinations of two modes of drilling predation, edge and wall drilling. The SPPAT approach is transferable to other paleoecologic and taphonomic data such as encrustation and bioerosion, allowing for standardized investigation of a wide range of biotic interactions.", "keyphrases": ["point pattern analysis", "trace", "sppat", "predation", "hotspot map"]}
{"id": "10.1111/joa.12446", "title": "A review of trabecular bone functional adaptation: what have we learned from trabecular analyses in extant hominoids and what can we apply to fossils?", "abstract": "Many of the unresolved debates in palaeoanthropology regarding evolution of particular locomotor or manipulative behaviours are founded in differing opinions about the functional significance of the preserved external fossil morphology. However, the plasticity of internal bone morphology, and particularly trabecular bone, allowing it to respond to mechanical loading during life means that it can reveal greater insight into how a bone or joint was used during an individual's lifetime. Analyses of trabecular bone have been commonplace for several decades in a human clinical context. In contrast, the study of trabecular bone as a method for reconstructing joint position, joint loading and ultimately behaviour in extant and fossil non\u2010human primates is comparatively new. Since the initial 2D studies in the late 1970s and 3D analyses in the 1990s, the utility of trabecular bone to reconstruct behaviour in primates has grown to incorporate experimental studies, expanded taxonomic samples and skeletal elements, and improved methodologies. However, this work, in conjunction with research on humans and non\u2010primate mammals, has also revealed the substantial complexity inherent in making functional inferences from variation in trabecular architecture. This review addresses the current understanding of trabecular bone functional adaptation, how it has been applied to hominoids, as well as other primates and, ultimately, how this can be used to better interpret fossil hominoid and hominin morphology. Because the fossil record constrains us to interpreting function largely from bony morphology alone, and typically from isolated bones, analyses of trabecular structure, ideally in conjunction with that of cortical structure and external morphology, can offer the best resource for reconstructing behaviour in the past.", "keyphrases": ["review", "trabecular bone", "functional adaptation", "behaviour"]}
{"id": "10.1017/S0094837300013634", "title": "Are brachiopods better than bivalves? Mechanisms of turbidity tolerance and their interaction with feeding in articulates", "abstract": "The dominance of Paleozoic articulate brachiopods in once-muddy environments may be explained by an array of mechanisms and structures that reject nonfood particles, in some cases without interruption of feeding: (1) behavioral flexibility of the lophophore and its individual filaments; (2) persistent, variable-speed rejection currents on the mantle, which sometimes concentrate pseudofeces in topographically controlled vortices; (3) costae and alae (which have many other probable functions); (4) inhalant currents elevated above substrate; (5) marginal setae. Some mantle currents parallel (and presumably augment) lophophore feeding currents; others diverge up to 90\u00b0 to provide rejection while feeding continues. Contrary to previous reports, the lateral cilia seem to be involved in rejection and may reverse. Repeated claims for the superiority of the gill of suspension-feeding bivalves over the \u201cweak\u201d individual filaments of the lophophore are probably false. In suspension-feeding bivalves, simultaneous feeding and rejection are likely to be hindered by fused gill elements and mucus-trapping of food. The energetically efficient articulates are predicted to have a competitive advantage over suspension-feeding bivalves when oxygen or food is limiting, as, for example, after a bolide impact.", "keyphrases": ["brachiopod", "bivalve", "paleozoic"]}
{"id": "paleo.005533", "title": "Phylogeny and diversification of bryozoans", "abstract": "Although only a small fraction of the estimated 6000 extant bryozoan species has been analysed in a molecular phylogenetic context, the resultant trees have increased our understanding of the interrelationships between major bryozoan groups, as well as between bryozoans and other metazoan phyla. Molecular systematic analyses have failed to recover the Lophophorata as a monophyletic clade until recently, when phylogenomic data placed the Brachiopoda as sister to a clade formed by Phoronida + Bryozoa. Among bryozoans, class Phylactolaemata has been shown to be the sister group of Gymnolaemata + Stenolaemata, corroborating earlier anatomical inferences. Despite persistent claims, there are no unequivocal bryozoans of Cambrian age: the oldest bryozoans are stenolaemates from the Tremadocian of China. Stenolaemates underwent a major radiation during the Ordovician, but the relationships between the six orders involved are poorly understood, mostly because the simple and plastic skeletons of stenolaemates make phylogenetic analyses difficult. Bryozoans were hard\u2010hit by the mass extinction/s in the late Permian and it was not until the Middle Jurassic that they began to rediversify, initially through the cyclostome stenolaemates. The most successful post\u2010Palaeozoic order (Cheilostomata) evolved a calcareous skeleton de novo from a soft\u2010bodied ancestor in the Late Jurassic, maintained a low diversity until the mid\u2010Cretaceous and then began to radiate explosively. A remarkable range of morphological structures in the form of highly modified zooidal polymorphs, or non\u2010zooidal or intrazooidal modular elements, is postulated to have evolved repeatedly in this group. Crucially, many of these structures have been linked to micropredator protection and can be interpreted as key traits linked to the diversification of cheilostomes.", "keyphrases": ["diversification", "bryozoan", "phylogenetic analysis", "zooid arrangement", "ctenostome-grade ancestor"]}
{"id": "paleo.003910", "title": "Evidence on relation of brain to endocranial cavity in oviraptorid dinosaurs", "abstract": "Brains in living tetrapods other than birds and mammals do not entirely fill the brain cavities. Examination of dinosaur braincases does not usually allow determination relating to how close walls of endocranial cavity lay to the surface of brain. The here described fragment of a skull roof of an oviraptorid dinosaur, Ingenia yanshini, shows perfectly preserved, numerous vascular imprints that cover the internal surfaces of frontals and parietals in the region roofing the cerebral hemispheres and cerebellum. This specimen shows that in oviraptorids the brain closely fitted the brain cavity, to the extent found in birds and mammals. Among dinosaurs, only one similar case has been previously reported in an ornithomimid, Dromiceiomimus brevitertius, but the preserved vascular imprints are less numerous and regular in this dinosaur than in Ingenia yanshini.", "keyphrases": ["brain", "endocranial cavity", "oviraptorid dinosaur", "skull roof", "theropod"]}
{"id": "10.4039/Ent133439-4", "title": "Flies and flowers: taxonomic diversity of anthophiles and pollinators", "abstract": "Abstract The Diptera are the second most important order among flower-visiting (anthophilous) and flower-pollinating insects worldwide. Their taxonomic diversity ranges from Nematocera to Brachycera, including most families within the suborders. Especially important are Syrphidae, Bombyliidae, and Muscoidea. Other families, especially of small flies, are less appreciated and often overlooked for their associations with flowers. We have compiled records of their flower visitations to show that they may be more prevalent than usually thought. Our knowledge of anthophilous Diptera needs to be enhanced by future research concerning (i) the significance of nocturnal Nematocera and acalypterate muscoids as pollinators, (ii) the extent to which the relatively ineffective pollen-carrying ability of some taxa can be compensated by the abundance of individuals, and (iii) the role of Diptera as pollinators of the first flowering plants (Angiospermae) by using phylogenetic and palaeontological evidence. Specializations in floral relationships involve the morphology of Diptera, especially of their mouthparts, nutritional requirements, and behaviour, as well as concomitant floral attributes. The South African flora has the most highly specialized relations with dipterous pollinators, but in arctic and alpine generalist fly\u2013flower relations are important in pollination and fly nutrition. R\u00e9sum\u00e9 Les dipt\u00e8res occupent le second rang au monde parmi les ordres d\u2019insectes qui visitent les fleurs (anthophiles) et qui assurent la pollinisation. Leur diversit\u00e9 taxonomique va des n\u00e9matoc\u00e8res aux brachyc\u00e8res et inclut presque toutes les familles de ces sous-ordres, en particulier les Syrphidae, les Bombyliidae et les Muscoidea qui occupent une place pr\u00e9pond\u00e9rante. Les associations des autres familles avec les fleurs, particuli\u00e8rement les familles de mouches de petite taille, passent souvent inaper\u00e7ues. Nous avons compil\u00e9 des donn\u00e9es sur leurs visites aux fleurs dans le but de d\u00e9montrer qu\u2019elles sont probablement plus importantes qu\u2019on ne le croit. Nos connaissances des dipt\u00e8res anthophiles doivent \u00eatre compl\u00e9t\u00e9es par d\u2019autres recherches (i) pour d\u00e9terminer l\u2019importance des n\u00e9matoc\u00e8res nocturnes et des musco\u00efdes acalypt\u00e8res comme pollinisateurs, (ii) pour \u00e9valuer jusqu\u2019\u00e0 quel point l\u2019inefficacit\u00e9 relative de certains taxons comme transporteurs de pollen peut \u00eatre compens\u00e9e par l\u2019abondance des individus et (iii) pour juger du r\u00f4le des dipt\u00e8res comme pollinisateurs des premi\u00e8res plantes \u00e0 fleurs (Angiospermae) en utilisant des donn\u00e9es phylog\u00e9n\u00e9tiques et pal\u00e9ontologiques. Les sp\u00e9cialisations de relations fleurs\u2013insectes sont bas\u00e9es sur des particularit\u00e9s morphologiques des dipt\u00e8res, surtout de leurs pi\u00e8ces buccales, sur leurs besoins nutritifs et sur leur comportement, en m\u00eame temps que sur les attributs correspondants des fleurs. La flore de l\u2019Afrique du Sud est celle qui a les relations les plus sp\u00e9cialis\u00e9es avec les dipt\u00e8res pollinisateurs. Cependant, dans les r\u00e9gions arctiques et alpines, des relations apparemment non sp\u00e9cialis\u00e9es entre les mouches et les fleurs sont importantes pour la pollinisation des fleurs et l\u2019alimentation des mouches. [Traduit par la R\u00e9daction]", "keyphrases": ["flower", "taxonomic diversity", "pollinator"]}
{"id": "10.1017/S0022336000023362", "title": "The \u201cevolution\u201d of Anomalocaris and its classification in the arthropod class Dinocarida (nov.) and order Radiodonta (nov.)", "abstract": "The remarkable \u201cevolution\u201d of the reconstructions of Anomalocaris, the extraordinary predator from the 515 million year old Middle Cambrian Burgess Shale of British Columbia, reflects the dramatic changes in our interpretation of early animal life on Earth over the past 100 years. Beginning in 1892 with a claw identified as the abdomen and tail of a phyllocarid crustacean, parts of Anomalocaris have been described variously as a jellyfish, a sea-cucumber, a polychaete worm, a composite of a jellyfish and sponge, or have been attached to other arthropods as appendages. Charles D. Walcott collected complete specimens of Anomalocaris nathorsti between 1911 and 1917, and a Geological Survey of Canada party collected an almost complete specimen of Anomalocaris canadensis in 1966 or 1967, but neither species was adequately described until 1985. At that time they were interpreted by Whittington and Briggs to be representatives of \u201ca hitherto unknown phylum.\u201d Here, using recently collected specimens, the two species are newly reconstructed and described in the genera Anomalocaris and Laggania, and interpreted to be members of an extinct arthropod class, Dinocarida, and order Radiodonta, new to science. The long history of inaccurate reconstruction and mistaken identification of Anomalocaris and Laggania exemplifies our great difficulty in visualizing and classifying, from fossil remains, the many Cambrian animals with no apparent living descendants.", "keyphrases": ["anomalocaris", "radiodonta", "appendage"]}
{"id": "paleo.012438", "title": "Artificial intelligence provides greater accuracy in the classification of modern and ancient bone surface modifications", "abstract": "Bone surface modifications are foundational to the correct identification of hominin butchery traces in the archaeological record. Until present, no analytical technique existed that could provide objectivity, high accuracy, and an estimate of probability in the identification of multiple structurally-similar and dissimilar marks. Here, we present a major methodological breakthrough that incorporates these three elements using Artificial Intelligence (AI) through computer vision techniques, based on convolutional neural networks. This method, when applied to controlled experimental marks on bones, yielded the highest rate documented to date of accurate classification (92%) of cut, tooth and trampling marks. After testing this method experimentally, it was applied to published images of some important traces purportedly indicating a very ancient hominin presence in Africa, America and Europe. The preliminary results are supportive of interpretations of ancient butchery in some places, but not in others, and suggest that new analyses of these controversial marks should be done following the protocol described here to confirm or disprove these archaeological interpretations.", "keyphrases": ["classification", "bone surface modification", "tooth"]}
{"id": "paleo.000895", "title": "Fossil skulls reveal that blood flow rate to the brain increased faster than brain volume during human evolution", "abstract": "The evolution of human cognition has been inferred from anthropological discoveries and estimates of brain size from fossil skulls. A more direct measure of cognition would be cerebral metabolic rate, which is proportional to cerebral blood flow rate (perfusion). The hominin cerebrum is supplied almost exclusively by the internal carotid arteries. The sizes of the foramina that transmitted these vessels in life can be measured in hominin fossil skulls and used to calculate cerebral perfusion rate. Perfusion in 11 species of hominin ancestors, from Australopithecus to archaic Homo sapiens, increases disproportionately when scaled against brain volume (the allometric exponent is 1.41). The high exponent indicates an increase in the metabolic intensity of cerebral tissue in later Homo species, rather than remaining constant (1.0) as expected by a linear increase in neuron number, or decreasing according to Kleiber's Law (0.75). During 3 Myr of hominin evolution, cerebral tissue perfusion increased 1.7-fold, which, when multiplied by a 3.5-fold increase in brain size, indicates a 6.0-fold increase in total cerebral blood flow rate. This is probably associated with increased interneuron connectivity, synaptic activity and cognitive function, which all ultimately depend on cerebral metabolic rate.", "keyphrases": ["blood flow rate", "brain volume", "measure", "hominin evolution", "fossil skull"]}
{"id": "paleo.001802", "title": "Analyzing Taphonomic Deformation of Ankylosaur Skulls Using Retrodeformation and Finite Element Analysis", "abstract": "Taphonomic deformation can make the interpretation of vertebrate fossil morphology difficult. The effects of taphonomic deformation are investigated in two ankylosaurid dinosaur taxa, Euoplocephalus tutus (to investigate effects on our understanding of intraspecific variation) and Minotaurasaurus ramachandrani (to investigate the validity of this genus). The ratio of orbit maximum rostrocaudal length to perpendicular height is used as a strain ellipse, which can be used to determine if ankylosaur skull fossils have been dorsoventrally compacted during fossilization and diagenesis. The software program Geomagic is used to retrodeform three-dimensional (3D) digital models of the ankylosaur skulls. The effects of sediment compaction are modeled using finite element analysis, and the resulting strain distributions are compared with the retrodeformed models as a test of the retrodeformation method. Taphonomic deformation can account for a large amount of intraspecific variation in Euoplocephalus, but finite element analysis and retrodeformation of Minotaurasaurus shows that many of its diagnostic features are unlikely to result from deformation.", "keyphrases": ["taphonomic deformation", "retrodeformation", "finite element analysis", "amount"]}
{"id": "10.1029/2008PA001676", "title": "Coupled Greenhouse Warming and Deep Sea Acidification in the Middle Eocene", "abstract": "[1]\u00a0The Middle Eocene Climatic Optimum (MECO) is an enigmatic warming event that represents an abrupt reversal in long-term cooling through the Eocene. In order to further assess the timing and nature of this event, we have assembled stable isotope and calcium carbonate concentration records from multiple Deep Sea Drilling Project and Ocean Drilling Program sites for the time interval between \u223c43 and 38 Ma. Revised stratigraphy at several sites and compilation of \u03b418O records place peak warming during the MECO event at 40.0 Ma (Chron C18n.2n). The identification of the \u03b418O excursion at sites in different geographic regions indicates that the climatic effects of this event were globally extensive. The total duration of the MECO event is estimated at \u223c500 ka, with peak warming lasting <100 ka. Assuming minimal glaciation in the late middle Eocene, \u223c4\u00b0\u20136\u00b0C total warming of both surface and deep waters is estimated during the MECO at the study sites. The interval of peak warming at \u223c40.0 Ma also coincided with a worldwide decline in carbonate accumulation at sites below 3000 m depth, reflecting a temporary shoaling of the calcite compensation depth. The synchroneity of deep-water acidification and globally extensive warming makes a persuasive argument that the MECO event was linked to a transient increase in atmospheric pCO2. The results of this study confirm previous reports of significant climatic instability during the middle Eocene. Furthermore, the direct link between warming and changes in the carbonate chemistry of the deep ocean provides strong evidence that changes in greenhouse gas concentrations exerted a primary control on short-term climate variability during this critical period of Eocene climate evolution.", "keyphrases": ["warming", "middle eocene", "meco"]}
{"id": "10.1017/S0094837300000300", "title": "Comparative physiology of suspension-feeding in living brachiopods and bivalves: evolutionary implications", "abstract": "This paper presents scaling equations relating suspension-feeding rates to body size for articulate brachiopods and bivalve molluscs, two classes which represent a significant component of the fossil record of marine benthic communities. Clearance (feeding) rates of five species of living articulate brachiopods and three species of epifaunal suspension-feeding bivalve molluscs collected from mid-latitude fjords of Newfoundland and New Zealand were measured in similar experimental conditions. In comparisons within and between the two classes, we found that both plectolophous and spirolophous brachiopods had significantly lower feeding rates than mytilids, which are filibranchs, but that a sympatric primitive eulamellibranch veneroid bivalve had rates comparable to the brachiopods. Articulate brachiopods do not appear to feed effectively at the high algal concentrations which bivalves can exploit. The data on comparative suspension-feeding rates support the hypothesis that past changes in diversity and distribution of bivalves and brachiopods may be related to an overall increase in energy flux and escalation of metabolic rates during the Phanerozoic.", "keyphrases": ["brachiopod", "bivalve", "algal concentration"]}
{"id": "paleo.007746", "title": "SNAKES OF THE SIWALIK GROUP (MIOCENE OF PAKISTAN): SYSTEMATICS AND RELATIONSHIP TO ENVIRONMENTAL CHANGE", "abstract": "The lower and middle Siwalik Group of the Potwar Plateau, Pakistan (Miocene, approximately 18 to 3.5 Ma) is a continuous fluvial sequence that preserves a dense fossil record of snakes. The record consists of approximately 1,500 vertebrae derived from surface-collection and screen-washing of bulk matrix. This record represents 12 identifiable taxa and morphotypes, including Python sp., Acrochordus dehmi, Gansophis potwarensis gen. et sp. nov., Bungarus sp., Chotaophis padhriensis, gen. et sp. nov., and Sivaophis downsi gen. et sp. nov. The record is dominated by Acrochordus dehmi, a fully-aquatic taxon, but diversity increases among terrestrial and semi-aquatic taxa beginning at approximately 10 Ma, roughly coeval with proxy data indicating the inception of the Asian monsoons and increasing seasonality on the Potwar Plateau. Taxonomic differences between the Siwalik Group and coeval European faunas indicate that South Asia was a distinct biogeographic theater from Europe by the middle Miocene. Differences between the Siwalik Group and extant snake faunas indicate significant environmental changes on the Plateau after the last fossil snake occurrences in the Siwalik section.", "keyphrases": ["miocene", "pakistan", "snake", "herpetofauna"]}
{"id": "paleo.000899", "title": "Identifying the oldest larva of a myrmeleontiformian lacewing \u2013 a morphometric approach", "abstract": "Neuroptera is one of the smaller ingroups of Holometabola, the ingroup of Insecta characterised by \u201ccomplete\u201d metamorphosis. Neuroptera comprises about 6000 species in the modern fauna, but appears to have been more diverse in the past. While adults distantly resemble certain moths or damselflies, the larval forms of Neuroptera are mostly fierce predators with prominent venom-injecting stylets. The most well-known of these larvae are probably those of antlions. Antlions and their closer relatives (silky lacewings, split-footed lacewings, ribbon-winged lacewings, spoon-winged lacewings, and owlflies) form a distinct monophyletic ingroup of Neuroptera, Myrmeleontiformia, hence the antlion-like forms. The fossil record of antlion-like larvae dates back far into the Cretaceous; many forms are known by exceptionally wellpreserved specimens entrapped in amber. The oldest fossil record of a neuropteran larva (not an antlion-like form) comes from Lebanese amber. Interestingly, the supposedly oldest record of an antlion-like larva is preserved in rock and comes from the famous Lower Cretaceous Crato Formation. We re-evaluate this fossil based on high-resolution composite photography. Due to the non-availability of many key characters, standard procedures for identifying the specimen to a more narrow ingroup remains challenging. Therefore, we used a morphometric approach. A combination of non-metric multidimensional scaling (NMDS), parallel coordinate plots and discriminant function analysis indicates that the fossil is a representative of the group Ascalaphidae (owlflies) + Myrmeleontidae (antlions). We discuss implications of this result for the fossil record of neuropteran larvae. These include the rather derived morphology of the oldest fossil larva of Myrmeleontiformia in contrast to previous expectations. Furthermore, fossils from soil dwellers can not only be expected to be found in amber, but also as compression fossils.", "keyphrases": ["larva", "lacewing", "morphometric approach"]}
{"id": "paleo.011314", "title": "Bias and Sensitivity in the Placement of Fossil Taxa Resulting from Interpretations of Missing Data", "abstract": "The utility of fossils in evolutionary contexts is dependent on their accurate placement in phylogenetic frameworks, yet intrinsic and widespread missing data make this problematic. The complex taphonomic processes occurring during fossilization can make it difficult to distinguish absence from non-preservation, especially in the case of exceptionally preserved soft-tissue fossils: is a particular morphological character (e.g., appendage, tentacle, or nerve) missing from a fossil because it was never there (phylogenetic absence), or just happened to not be preserved (taphonomic loss)? Missing data have not been tested in the context of interpretation of non-present anatomy nor in the context of directional shifts and biases in affinity. Here, complete taxa, both simulated and empirical, are subjected to data loss through the replacement of present entries (1s) with either missing (?s) or absent (0s) entries. Both cause taxa to drift down trees, from their original position, toward the root. Absolute thresholds at which downshift is significant are extremely low for introduced absences (two entries replaced, 6% of present characters). The opposite threshold in empirical fossil taxa is also found to be low; two absent entries replaced with presences causes fossil taxa to drift up trees. As such, only a few instances of non-preserved characters interpreted as absences will cause fossil organisms to be erroneously interpreted as more primitive than they were in life. This observed sensitivity to coding non-present morphology presents a problem for all evolutionary studies that attempt to use fossils to reconstruct rates of evolution or unlock sequences of morphological change. Stem-ward slippage, whereby fossilization processes cause organisms to appear artificially primitive, appears to be a ubiquitous and problematic phenomenon inherent to missing data, even when no decay biases exist. Absent characters therefore require explicit justification and taphonomic frameworks to support their interpretation.", "keyphrases": ["placement", "fossil taxa", "taphonomic process", "morphological character", "misinterpretation"]}
{"id": "paleo.006029", "title": "Links between global taxonomic diversity, ecological diversity and the expansion of vertebrates on land", "abstract": "Tetrapod biodiversity today is great; over the past 400 Myr since vertebrates moved onto land, global tetrapod diversity has risen exponentially, punctuated by losses during major extinctions. There are links between the total global diversity of tetrapods and the diversity of their ecological roles, yet no one fully understands the interplay of these two aspects of biodiversity and a numerical analysis of this relationship has not so far been undertaken. Here we show that the global taxonomic and ecological diversity of tetrapods are closely linked. Throughout geological time, patterns of global diversity of tetrapod families show 97 per cent correlation with ecological modes. Global taxonomic and ecological diversity of this group correlates closely with the dominant classes of tetrapods (amphibians in the Palaeozoic, reptiles in the Mesozoic, birds and mammals in the Cenozoic). These groups have driven ecological diversity by expansion and contraction of occupied ecospace, rather than by direct competition within existing ecospace and each group has used ecospace at a greater rate than their predecessors.", "keyphrases": ["ecological diversity", "vertebrate", "land", "diversification"]}
{"id": "paleo.003120", "title": "A new stem group echinoid from the Triassic of China leads to a revised macroevolutionary history of echinoids during the end-Permian mass extinction", "abstract": "The Permian\u2013Triassic bottleneck has long been thought to have drastically altered the course of echinoid evolution, with the extinction of the entire echinoid stem group having taken place during the end-Permian mass extinction. The Early Triassic fossil record of echinoids is, however, sparse, and new fossils are paving the way for a revised interpretation of the evolutionary history of echinoids during the Permian\u2013Triassic crisis and Early Mesozoic. A new species of echinoid, Yunnanechinus luopingensis n. sp. recovered from the Middle Triassic (Anisian) Luoping Biota fossil Lagerst\u00e4tte of South China, displays morphologies that are not characteristic of the echinoid crown group. We have used phylogenetic analyses to further demonstrate that Yunnanechinus is not a member of the echinoid crown group. Thus a clade of stem group echinoids survived into the Middle Triassic, enduring the global crisis that characterized the end-Permian and Early Triassic. Therefore, stem group echinoids did not go extinct during the Palaeozoic, as previously thought, and appear to have coexisted with the echinoid crown group for at least 23 million years. Stem group echinoids thus exhibited the Lazarus effect during the latest Permian and Early Triassic, while crown group echinoids did not.", "keyphrases": ["echinoid", "end-permian mass extinction", "phylogenetic analysis"]}
{"id": "10.1029/2009GL041436", "title": "Ocean chemistry and atmospheric CO2 sensitivity to carbon perturbations throughout the Cenozoic", "abstract": "We assess the response of atmospheric CO2 (pCO2) and ocean chemistry to carbon perturbations, placing modern carbon\u2010cycle sensitivity in the context of the Cenozoic. We use the carbon\u2010cycle model LOSCAR to study the effect of perturbations over the past 67 Ma. Our results indicate that atmospheric CO2 and surface ocean pH were slightly more sensitive to carbon perturbations during the Miocene (\u223c15 Ma ago) compared to modern conditions and less sensitive during the earlier part of the Cenozoic. We find that the sensitivity to carbon input at the Paleocene\u2010Eocene boundary (\u223c56 Ma ago) was most likely lower compared to modern conditions. Further, we show that the Cenozoic evolution of steady state pCO2 and seawater Mg/Ca ratios is critical for the system's sensitivity to a carbon release.", "keyphrases": ["carbon perturbation", "cenozoic", "ocean chemistry"]}
{"id": "paleo.002266", "title": "A roller-like bird (Coracii) from the Early Eocene of Denmark", "abstract": "The fossil record of crown group birds (Neornithes) prior to the Cretaceous-Paleogene boundary is scarce and fragmentary. Early Cenozoic bird fossils are more abundant, but are typically disarticulated and/or flattened. Here we report the oldest roller (Coracii), Septencoracias morsensis gen. et sp. nov. (Primobucconidae), based on a new specimen from the Early Eocene (about 54 million years ago) Fur Formation of Denmark. The new fossil is a nearly complete, three-dimensionally preserved and articulated skeleton. It lies at the lower end of the size range for extant rollers. Salient diagnostic features of Septencoracias relative to other Coracii include the proportionally larger skull and the small, ovoid and dorsally positioned narial openings. Our discovery adds to the evidence that the Coracii had a widespread northern hemisphere distribution in the Eocene. Septencoracias is the oldest substantial record of the Picocoraciae and provides a reliable calibration point for molecular phylogenetic studies.", "keyphrases": ["roller-like bird", "early eocene", "primobucconidae", "geranopterus"]}
{"id": "10.5194/cp-16-1953-2020", "title": "Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene\u2013Eocene Thermal Maximum (PETM), and latest Paleocene", "abstract": "Abstract. Accurate estimates of past global mean surface temperature (GMST) help to\ncontextualise future climate change and are required to estimate the\nsensitivity of the climate system to CO2 forcing through Earth's history.\nPrevious GMST estimates for the latest Paleocene and early Eocene\n(\u223c57 to 48 million years ago) span a wide range\n(\u223c9 to 23\u2009\u2218C higher than pre-industrial) and\nprevent an accurate assessment of climate sensitivity during this extreme\ngreenhouse climate interval. Using the most recent data compilations, we\nemploy a multi-method experimental framework to calculate GMST during the\nthree DeepMIP target intervals: (1) the latest Paleocene (\u223c57\u2009Ma), (2)\u00a0the Paleocene\u2013Eocene Thermal Maximum (PETM; 56\u2009Ma), and (3)\u00a0the early\nEocene Climatic Optimum (EECO; 53.3 to 49.1\u2009Ma). Using six different\nmethodologies, we find that the average GMST estimate (66\u2009% confidence)\nduring the latest Paleocene, PETM, and EECO was 26.3\u2009\u2218C (22.3 to\n28.3\u2009\u2218C), 31.6\u2009\u2218C (27.2 to 34.5\u2009\u2218C), and\n27.0\u2009\u2218C (23.2 to 29.7\u2009\u2218C), respectively. GMST estimates\nfrom the EECO are \u223c10 to 16\u2009\u2218C warmer than\npre-industrial, higher than the estimate given by the Intergovernmental Panel on Climate Change (IPCC) 5th\nAssessment Report (9 to 14\u2009\u2218C higher than pre-industrial).\nLeveraging the large \u201csignal\u201d associated with these extreme warm climates,\nwe combine estimates of GMST and CO2 from the latest Paleocene, PETM,\nand EECO to calculate gross estimates of the average climate sensitivity\nbetween the early Paleogene and today. We demonstrate that \u201cbulk\u201d\nequilibrium climate sensitivity (ECS; 66\u2009% confidence) during the latest\nPaleocene, PETM, and EECO is 4.5\u2009\u2218C (2.4 to 6.8\u2009\u2218C),\n3.6\u2009\u2218C (2.3 to 4.7\u2009\u2218C), and 3.1\u2009\u2218C (1.8 to\n4.4\u2009\u2218C) per doubling of CO2. These values are generally\nsimilar to those assessed by the IPCC (1.5 to 4.5\u2009\u2218C per doubling\nCO2) but appear incompatible with low ECS values (<1.5 per\ndoubling\u00a0CO2).\n", "keyphrases": ["surface temperature", "climate sensitivity", "paleocene"]}
{"id": "paleo.000023", "title": "Pampean megamammals in Europe: the fossil collections from Santiago Roth", "abstract": "Santiago Roth was a Swiss fossil finder, naturalist, and paleontologist that emigrated to Argentina in 1866. His work largely influenced the discipline in the country at the end of the twentieth century, particularly the stratigraphy of the Pampean region. Some of his collections of Pampean fossils were sold to museums and private collectors in Europe and were accompanied by elaborated catalogues. Fossils in the Roth's catalogues N\u00b0 2 and 3 are housed today in the Natural History Museum of Denmark, fossils from catalogues N\u00b0 4 to 6, were sold to Swiss museums, with Catalogue N\u00b0 5 currently housed at the Department of Paleontology, Universit\u00e4t Z\u00fcrich. Here, we provide a general framework on the stratigraphy from the Roth's Pampean fossil sites, summarize the history of the Pampean fossils in Europe originally collected by Roth, and provide historical and curatorial details of the Roth's collection at the", "keyphrases": ["europe", "santiago roth", "pampean region"]}
{"id": "10.1017/S0016756817000875", "title": "A lifetime of the Variscan orogenic plateau from uplift to collapse as recorded by the Prague Basin, Bohemian Massif", "abstract": "Abstract The Ordovician to Middle Devonian Prague Basin, Bohemian Massif, represents the shallowest crust of the Variscan orogen corresponding to c. 1\u20134 km palaeodepth. The basin was inverted and multiply deformed during the Late Devonian to early Carboniferous Variscan orogeny, and its structural inventory provides an intriguing record of complex geodynamic processes that led to growth and collapse of a Tibetan-type orogenic plateau. The northeastern part of the Prague Basin is a simple syncline cross-cut by reverse/thrust faults and represents a doubly vergent compressional fan accommodating c. 10\u201319 % ~NW\u2013SE shortening, only minor syncline axis-parallel extension and significant crustal thickening. The compressional structures were locally overprinted by vertical shortening, kinematically compatible with ductile normal shear zones that exhumed deep crust in the orogen's interior at c. 346\u2013337 Ma. On a larger scale, the deformation history of the Prague Syncline is consistent with building significant palaeoelevation during Variscan plate convergence. Based on a synthesis of finite deformation parameters observed across the upper crust in the centre of the Bohemian Massif, we argue for a differentiated within-plateau palaeotopography consisting of domains of local thickening alternating with topographic depressions over lateral extrusion zones. The plateau growth, involving such complex three-dimensional internal deformations, was terminated by its collapse driven by multiple interlinked processes including gravity, voluminous magma emplacement and thermal softening in the hinterland, and far-field plate-boundary forces resulting from the relative dextral motion of Gondwana and Laurussia.", "keyphrases": ["orogenic plateau", "prague basin", "bohemian massif"]}
{"id": "10.1144/SP423.9", "title": "The global Hangenberg Crisis (Devonian\u2013Carboniferous transition): review of a first-order mass extinction", "abstract": "Abstract The global Hangenberg Crisis near the Devonian\u2013Carboniferous boundary (DCB) represents a mass extinction that is of the same scale as the so-called \u2018Big Five\u2019 first-order Phanerozoic events. It played an important role in the evolution of many faunal groups and destroyed complete ecosystems but affected marine and terrestrial environments at slightly different times within a short time span of c. 100\u2013300 kyr. The lower crisis interval in the uppermost Famennian started as a prelude with a minor eustatic sea-level fall, followed rather abruptly by pantropically widespread black shale deposition (Hangenberg Black Shale and equivalents). This transgressive and hypoxic/anoxic phase coincided with a global carbonate crisis and perturbation of the global carbon cycle as evidenced by a distinctive positive carbon isotope excursion, probably as a consequence of climate/salinity-driven oceanic overturns and outer-shelf eutrophication. It is the main extinction level for marine biota, especially for ammonoids, trilobites, conodonts, stromatoporoids, corals, some sharks, and deeper-water ostracodes, but probably also for placoderms, chitinozoans and early tetrapods. Extinction rates were lower for brachiopods, neritic ostracodes, bryozoans and echinoderms. Extinction patterns were similar in widely separate basins of the western and eastern Prototethys, while a contemporaneous marine macrofauna record from high latitudes is missing altogether. The middle crisis interval is characterized by a gradual but major eustatic sea-level fall, probably in the scale of more than 100 m, that caused the progradation of shallow-water siliciclastics (Hangenberg Sandstone and equivalents) and produced widespread unconformities due to reworking and non-deposition. The glacio-eustatic origin of this global regression is proven by miospore correlation with widespread diamictites of South America and South and North Africa, and by the evidence for significant tropical mountain glaciers in eastern North America. This isolated and short-lived plunge from global greenhouse into icehouse conditions may follow the significant drawdown of atmospheric CO2 levels due to the prior massive burial of organic carbon during the global deposition of black shales. Increased carbon recycling by intensified terrestrial erosion in combination with the arrested burial of carbonates may have led to a gradual rise of CO2 levels, re-warming, and a parallel increase in the influx of land-derived nutrients. The upper crisis interval in the uppermost Famennian is characterized by initial post-glacial transgression and a second global carbon isotope spike, as well as by opportunistic faunal blooms and the early re-radiation of several fossil groups. Minor reworking events and unconformities give evidence for continuing smaller-scale oscillations of sea-level and palaeoclimate. These may explain the terrestrial floral change near the Famennian\u2013Tournaisian boundary and contemporaneous, evolutionarily highly significant extinctions of survivors of the main crisis. Still poorly understood small-scale events wiped out the last clymeniid ammonoids, phacopid trilobites, placoderms and some widespread brachiopod and foraminiferan groups. The post-crisis interval in the lower Tournaisian is marked by continuing eustatic rise (e.g. flooding of the Old Red Continent), and significant radiations in a renewed greenhouse time. But the recovery had not yet reached the pre-crisis level when it was suddenly interrupted by the global, second-order Lower Alum Shale Event at the base of the middle Tournaisian.", "keyphrases": ["global hangenberg crisis", "review", "mass extinction", "hangenberg black shale", "devonian-carboniferous transition"]}
{"id": "10.1111/j.1475-4983.2005.00525.x", "title": "ONTOGENY AND HETEROCHRONY IN THE EARLY CAMBRIAN ORYCTOCEPHALID TRILOBITES CHANGASPIS, DUYUNASPIS AND BALANGIA FROM CHINA", "abstract": "Abstract:\u2002 Ontogenies are described for the first time for three species of Early Cambrian oryctocephalid trilobites: the oryctocephaline Changaspis elongata Lee, in Chien and the oryctocarines Duyunaspis duyunensis Chang and Chien, in Zhou et al. and Balangia balangensis Chien from the Balang Formation in eastern Ghuizhou Province, south\u2010west China. The complete protaspid to holaspid ontogeny for Duyunaspis duyunensis and incomplete meraspid to holaspid ontogenies for Changaspis elongata and Balangia balangensis are described. The relative degree of ontogenetic variation within the lineage Duyunaspis duyunensis\u2013Balangia balangensis is analysed and indicates that Balangia may have evolved from Duyunaspis by paedomorphosis. Decrease in thoracic segment number and concomitant increase in pygidial segment number in the later genus mirrors the pattern seen in the evolution of another oryctocephalid genus, Arthricocephalus. In both cases, selection was probably targeting an increase in cephalic convexity. This resulted in the evolution of a larger pygidium due to increased elevation of the axis above the substrate. The ontogenetic development of Changaspis provides evidence supporting the view that the Oryctocarinae may be considered as paedomorphic descendants of the Oryctocephalinae.", "keyphrases": ["duyunaspis", "balangia", "paedomorphosis", "ontogeny"]}
{"id": "paleo.007970", "title": "Current understanding on the Cambrian Explosion: questions and answers", "abstract": "The Cambrian Explosion by nature is a three-phased explosion of animal body plans alongside episodic biomineralization, pulsed change of generic diversity, body size variation, and progressive increase of ecosystem complexity. The Cambrian was a time of crown groups nested by numbers of stem groups with a high-rank taxonomy of Linnaean system (classes and above). Some stem groups temporarily succeeded while others were ephemeral and underrepresented by few taxa. The high number of stem groups in the early history of animals is a major reason for morphological gaps across phyla that we see today. Most phylum-level clades achieved their maximal disparity (or morphological breadth) during the time interval close to their first appearance in the fossil record during the early Cambrian, whereas others, principally arthropods and chordates, exhibit a progressive exploration of morphospace in subsequent Phanerozoic. The overall envelope of metazoan morphospace occupation was already broad in the early Cambrian though it did not reach maximal disparity nor has diminished significantly as a consequence of extinction since the Cambrian. Intrinsic and extrinsic causes were extensively discussed but they are merely prerequisites for the Cambrian Explosion. Without the molecular evolution, there could be no Cambrian Explosion. However, the developmental system is alone insufficient to explain Cambrian Explosion. Time-equivalent environmental changes were often considered as extrinsic causes, but the time coincidence is also insufficient to establish causality. Like any other evolutionary event, it is the ecology that make the Cambrian Explosion possible though ecological processes failed to cause a burst of new body plans in the subsequent evolutionary radiations. The Cambrian Explosion is a polythetic event in natural history and manifested in many aspects. No simple, single cause can explain the entire phenomenon.", "keyphrases": ["cambrian explosion", "animal body", "episodic biomineralization"]}
{"id": "paleo.011273", "title": "The Oldest Caseid Synapsid from the Late Pennsylvanian of Kansas, and the Evolution of Herbivory in Terrestrial Vertebrates", "abstract": "The origin and early evolution of amniotes (fully terrestrial vertebrates) led to major changes in the structure and hierarchy of terrestrial ecosystems. The first appearance of herbivores played a pivotal role in this transformation. After an early bifurcation into Reptilia and Synapsida (including mammals) 315 Ma, synapsids dominated Paleozoic terrestrial vertebrate communities, with the herbivorous caseids representing the largest vertebrates on land. Eocasea martini gen. et sp. nov., a small carnivorous caseid from the Late Carboniferous, extends significantly the fossil record of Caseidae, and permits the first clade-based study of the origin and initial evolution of herbivory in terrestrial tetrapods. Our results demonstrate for the first time that large caseid herbivores evolved from small, non-herbivorous caseids. This pattern is mirrored by three other clades, documenting multiple, independent, but temporally staggered origins of herbivory and increase in body size among early terrestrial tetrapods, leading to patterns consistent with modern terrestrial ecosystem.", "keyphrases": ["late pennsylvanian", "herbivory", "terrestrial vertebrate", "caseidae", "body size"]}
{"id": "paleo.004773", "title": "Climate constrains the evolutionary history and biodiversity of crocodylians", "abstract": "The fossil record of crocodylians and their relatives (pseudosuchians) reveals a rich evolutionary history, prompting questions about causes of long-term decline to their present-day low biodiversity. We analyse climatic drivers of subsampled pseudosuchian biodiversity over their 250 million year history, using a comprehensive new data set. Biodiversity and environmental changes correlate strongly, with long-term decline of terrestrial taxa driven by decreasing temperatures in northern temperate regions, and biodiversity decreases at lower latitudes matching patterns of increasing aridification. However, there is no relationship between temperature and biodiversity for marine pseudosuchians, with sea-level change and post-extinction opportunism demonstrated to be more important drivers. A \u2018modern-type' latitudinal biodiversity gradient might have existed throughout pseudosuchian history, and range expansion towards the poles occurred during warm intervals. Although their fossil record suggests that current global warming might promote long-term increases in crocodylian biodiversity and geographic range, the 'balancing forces' of anthropogenic environmental degradation complicate future predictions.", "keyphrases": ["biodiversity", "crocodylian", "latitude", "aridification"]}
{"id": "paleo.006076", "title": "The Triassic to Early Jurassic palynological record of the Tarim Basin, China", "abstract": "The Tarim Basin, located in northwestern China, is an important oil-bearing region, and the extensive non-marine Mesozoic successions make this a key location for understanding environmental changes through the Triassic and Jurassic. Palynological analyses on samples from Lunnan-1 and Tazhong-1 drill cores from the northern and central part of the Tarim Basin reveal wellpreserved spore-pollen assemblages. Five palynological assemblages, i.e. Tarim Triassic 1 (TT1)-Tarim Triassic 4 (TT4) and Tarim Jurassic 1 (TJ1), spanning the Early Triassic to Early Jurassic were identified based on compositional changes, which are supported by ordination of samples using non-metric multidimensional scaling (NMDS). The Early Triassic assemblages possess abundant bryophytes and Densoisporites spp.-producers, which potentially represent a recovery succession follow-ing the end-Permian event. The Late Triassic spore-pollen assemblages are more similar to those of the North China Palynofloral Province compared to the South China Province. Based on our phytogeographic analysis, we propose that the western section of the boundary between the North and South China palynofloras should be placed at the southern margin of the Tarim Basin.", "keyphrases": ["triassic", "tarim basin", "china"]}
{"id": "paleo.010779", "title": "A new era in palaeomicrobiology: prospects for ancient dental calculus as a long-term record of the human oral microbiome", "abstract": "The field of palaeomicrobiology is dramatically expanding thanks to recent advances in high-throughput biomolecular sequencing, which allows unprecedented access to the evolutionary history and ecology of human-associated and environmental microbes. Recently, human dental calculus has been shown to be an abundant, nearly ubiquitous, and long-term reservoir of the ancient oral microbiome, preserving not only microbial and host biomolecules but also dietary and environmental debris. Modern investigations of native human microbiota have demonstrated that the human microbiome plays a central role in health and chronic disease, raising questions about changes in microbial ecology, diversity and function through time. This paper explores the current state of ancient oral microbiome research and discusses successful applications, methodological challenges and future possibilities in elucidating the intimate evolutionary relationship between humans and their microbes.", "keyphrases": ["palaeomicrobiology", "dental calculus", "oral microbiome"]}
{"id": "paleo.004187", "title": "Large palaeophiid and nigerophiid snakes from Paleogene Trans-Saharan Seaway deposits of Mali", "abstract": "The Paleogene was a time of high diversity for snakes, and was characterized by some of the largest species known to have existed. Among these snakes were pan-Tethyan marine species of Nigerophiidae and Palaeophiidae. The latter family included the largest sea snake, Palaeophis colossaeus, known from the Trans-Saharan Seaway of Mali during the Eocene. This paper describes new material collected from Malian Trans-Saharan Seaway deposits, including additional material of Palaeophis colossaeus, a new, large species of nigerophiid, Amananulam sanogoi gen. et sp. nov., and a medium-sized snake of indeterminate affinities. The material provides new information on the intracolumnar variation of the vertebral column in Palaeophis colossaeus. We estimate the total length of each species by regression of vertebral measurements on body size. Both Palaeophis colossaeus and Amananulam sanogoi gen. et sp. nov. are the largest or among the largest members of their respective clades. The large size of Tethyan snakes may be indicative of higher temperatures in the tropics than are present today.", "keyphrases": ["snake", "paleogene", "trans-saharan seaway deposit"]}
{"id": "paleo.002150", "title": "The evolution and extinction of the ichthyosaurs from the perspective of quantitative ecospace modelling", "abstract": "The role of niche specialization and narrowing in the evolution and extinction of the ichthyosaurs has been widely discussed in the literature. However, previous studies have concentrated on a qualitative discussion of these variables only. Here, we use the recently developed approach of quantitative ecospace modelling to provide a high-resolution quantitative examination of the changes in dietary and ecological niche experienced by the ichthyosaurs throughout their evolution in the Mesozoic. In particular, we demonstrate that despite recent discoveries increasing our understanding of taxonomic diversity among the ichthyosaurs in the Cretaceous, when viewed from the perspective of ecospace modelling, a clear trend of ecological contraction is visible as early as the Middle Jurassic. We suggest that this ecospace redundancy, if carried through to the Late Cretaceous, could have contributed to the extinction of the ichthyosaurs. Additionally, our results suggest a novel model to explain ecospace change, termed the \u2018migration model\u2019.", "keyphrases": ["ichthyosaur", "perspective", "quantitative ecospace"]}
{"id": "10.1002/2014JB011213", "title": "Magnetic detection and characterization of biogenic magnetic minerals: A comparison of ferromagnetic resonance and first\u2010order reversal curve diagrams", "abstract": "Biogenic magnetic minerals produced by magnetotactic bacteria occur ubiquitously in natural aquatic environments. Their identification and characterization are important for interpretation of paleomagnetic and environmental magnetic records. We compare two magnetic methods for their identification and characterization in a diverse set of sedimentary environments: ferromagnetic resonance (FMR) spectroscopy and first\u2010order reversal curve (FORC) diagrams, constrained by transmission electron microscope observations. The advantages and limitations of each method are evaluated. FMR analysis provides a strong diagnostic indicator because of its ability to detect the strong shape anisotropy that arises from the biogenic chain architecture, but it can be obscured in mixed magnetic mineral assemblages. We develop a new FMR fitting approach that enables separation and characterization of biogenic components in natural samples. FMR spectral fitting on magnetofossil\u2010bearing samples does not always reveal a strong signature of biogenic magnetite with <111>\u2010aligned chains, in contrast to whole magnetotactic bacteria cells. This indicates that strictly <111>\u2010aligned chains are not as common in magnetofossil assemblages, due to either chain collapse or different crystallographic axis orientations. FORC analysis provides an excellent tool for isolating the biogenic component as a \u201ccentral ridge\u201d signature with peak switching field distribution between ~20 and 60 mT. We also analyzed tuff samples with similar FMR characteristics to biogenic magnetite chains, which can cause ambiguity. We propose a magnetic protocol to improve the robustness and efficiency of biogenic magnetite identification and past microbial activity in a wide range of environments.", "keyphrases": ["characterization", "magnetic mineral", "resonance"]}
{"id": "paleo.006380", "title": "Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities", "abstract": "Most knowledge about the structure, function, and evolution of early compound eyes is based on investigations in trilobites. However, these studies dealt mainly with the cuticular lenses and little was known about internal anatomy. Only recently some data on crystalline cones and retinula cells were reported for a Cambrian trilobite species. Here, we describe internal eye structures of two other trilobite genera. The Ordovician Asaphus sp. reveals preserved crystalline cones situated underneath the cuticular lenses. The same is true for the Devonian species Archegonus (Waribole) warsteinensis, which in addition shows the fine structure of the rhabdom in the retinula cells. These results suggest that an apposition eye with a crystalline cone is ancestral for Trilobita. The overall similarity of trilobite eyes to those of myriapods, crustaceans, and hexapods corroborates views of a phylogenetic position of trilobites in the stem lineage of Mandibulata.", "keyphrases": ["compound eye", "crystalline cone", "rhabdom", "trilobite", "existence"]}
{"id": "10.1666/13-088", "title": "The walking dead: Blender as a tool for paleontologists with a case study on extinct arachnids", "abstract": "Abstract This paper serves two roles. First, it acts as an introduction to Blender, an open-source computer graphics program, which can be of utility to paleontologists. To lessen the software's otherwise steep learning curve, a step-by-step guide to create an idealized reconstruction of a fossil in the form of a three-dimensional model in Blender, or to use the software to render results from \u2018virtual paleontology' techniques, is provided as an online supplemental data file. Second, here we demonstrate the use of Blender with a case study on the extinct trigonotarbid arachnids. We report the limb articulations of members of the Devonian genus Palaeocharinus on the basis of exceptionally preserved fossils from the Rhynie Cherts of Scotland. We use these newly reported articulations to create a Blender model, and draw comparisons with the gait of extant arachnids to produce as accurate a representation of the trigonotarbid flexing its limbs and walking as possible, presented in additional online supplemental data files. Knowledge of the limb articulations of trigonotarbid arachnids also allows us to discuss their functional morphology: trigonotarbids' limbs and gait were likely comparable to extant cursorial spiders, but lacked some innovations seen in more derived arachnids.", "keyphrases": ["blender", "paleontologist", "arachnid"]}
{"id": "10.1111/cla.12156", "title": "Hennig's semaphoront concept and the use of ontogenetic stages in phylogenetic reconstruction", "abstract": "A new practice in systematics, \u201csemaphoront\u201d coding, treats developmental stages as terminals, and it derives from Hennig's concept of the same name. Semaphoront coding has been implemented recently by Lamsdell and Selden (BMC Evol. Biol., 2013, 13:98) and Wolfe and Hegna (Cladistics, 2014, 30:366) in an effort to understand the relationships of fossil taxa of unknown developmental stage. We submit that this approach is antithetical to cladistic practice and constitutes a gross misunderstanding of Hennig's original idea. Here we review the concept of the semaphoront and clarify the role of the semaphoront in phylogenetic systematics. We contend that treating ontogenetic stages as terminals both violates tenets of phylogenetic systematics and oversimplifies the complexity of developmental processes. We advocate Hennig's alternative of including data from as many semaphoronts as possible, but implemented using the superior total evidence framework. Finally, we contend that the application of semaphoront coding to any palaeontological question requires invoking multiple, unjustified assumptions, and ultimately will not yield a possible phylogenetic solution. A total evidence approach can grapple with the placement of fossil developmental stages, if only imperfectly.", "keyphrases": ["concept", "ontogenetic stage", "hennig"]}
{"id": "paleo.012556", "title": "New Protocetid Whale from the Middle Eocene of Pakistan: Birth on Land, Precocial Development, and Sexual Dimorphism", "abstract": "Background Protocetidae are middle Eocene (49\u201337 Ma) archaeocete predators ancestral to later whales. They are found in marine sedimentary rocks, but retain four legs and were not yet fully aquatic. Protocetids have been interpreted as amphibious, feeding in the sea but returning to land to rest. Methodology/Principal Findings Two adult skeletons of a new 2.6 meter long protocetid, Maiacetus inuus, are described from the early middle Eocene Habib Rahi Formation of Pakistan. M. inuus differs from contemporary archaic whales in having a fused mandibular symphysis, distinctive astragalus bones in the ankle, and a less hind-limb dominated postcranial skeleton. One adult skeleton is female and bears the skull and partial skeleton of a single large near-term fetus. The fetal skeleton is positioned for head-first delivery, which typifies land mammals but not extant whales, evidence that birth took place on land. The fetal skeleton has permanent first molars well mineralized, which indicates precocial development at birth. Precocial development, with attendant size and mobility, were as critical for survival of a neonate at the land-sea interface in the Eocene as they are today. The second adult skeleton is the most complete known for a protocetid. The vertebral column, preserved in articulation, has 7 cervicals, 13 thoracics, 6 lumbars, 4 sacrals, and 21 caudals. All four limbs are preserved with hands and feet. This adult is 12% larger in linear dimensions than the female skeleton, on average, has canine teeth that are 20% larger, and is interpreted as male. Moderate sexual dimorphism indicates limited male-male competition during breeding, which in turn suggests little aggregation of food or shelter in the environment inhabited by protocetids. Conclusions/Significance Discovery of a near-term fetus positioned for head-first delivery provides important evidence that early protocetid whales gave birth on land. This is consistent with skeletal morphology enabling Maiacetus to support its weight on land and corroborates previous ideas that protocetids were amphibious. Specimens this complete are virtual \u2018Rosetta stones\u2019 providing insight into functional capabilities and life history of extinct animals that cannot be gained any other way.", "keyphrases": ["middle eocene", "pakistan", "birth", "maiacetus", "fetus"]}
{"id": "10.1080/02724634.2012.652051", "title": "New Fossil Penguins (Aves, Sphenisciformes) from the Oligocene of New Zealand Reveal the Skeletal Plan of Stem Penguins", "abstract": "ABSTRACT \n Three skeletons collected from the late Oligocene Kokoamu Greensand of New Zealand are among the most complete Paleogene penguins known. These specimens, described here as Kairuku waitaki, gen. et sp. nov., and Kairuku grebneffi, sp. nov., reveal new details of key elements of the stem penguin skeleton associated with underwater flight, including the sternum, flipper, and pygostyle. Relative proportions of the trunk, flippers, and hind limbs can now be determined from a single individual for the first time, offering insight into the body plan of stem penguins and improved constraints on size estimates for \u2018giant\u2019 taxa. Kairuku is characterized by an elongate, narrow sternum, a short and flared coracoid, an elongate narrow flipper, and a robust hind limb. The pygostyle of Kairuku lacks the derived triangular cross-section seen in extant penguins, suggesting that the rectrices attached in a more typical avian pattern and the tail may have lacked the propping function utilized by living penguins. New materials described here, along with re-study of previously described specimens, resolve several long-standing phylogenetic, biogeographic, and taxonomic issues stemming from the inadequate comparative material of several of the first-named fossil penguin species. An array of partial associated skeletons from the Eocene\u2014Oligocene of New Zealand historically referred to Palaeeudyptes antarcticus or Palaeeudyptes sp. are recognized as at least five distinct species: Palaeeudyptes antarcticus, Palaeeudyptes marplesi, Kairuku waitaki, Kairuku grebneffi, and an unnamed Burnside Formation species.", "keyphrases": ["penguin", "oligocene", "new zealand"]}
{"id": "paleo.009444", "title": "Cretaceous dinosaur bone contains recent organic material and provides an environment conducive to microbial communities", "abstract": "Fossils were thought to lack original organic molecules, but chemical analyses show that some can survive. Dinosaur bone has been proposed to preserve collagen, osteocytes, and blood vessels. However, proteins and labile lipids are diagenetically unstable, and bone is a porous open system, allowing microbial/molecular flux. These \u2018soft tissues\u2019 have been reinterpreted as biofilms. Organic preservation versus contamination of dinosaur bone was examined by freshly excavating, with aseptic protocols, fossils and sedimentary matrix, and chemically/biologically analyzing them. Fossil \u2018soft tissues\u2019 differed from collagen chemically and structurally; while degradation would be expected, the patterns observed did not support this. 16S rRNA amplicon sequencing revealed that dinosaur bone hosted an abundant microbial community different from lesser abundant communities of surrounding sediment. Subsurface dinosaur bone is a relatively fertile habitat, attracting microbes that likely utilize inorganic nutrients and complicate identification of original organic material. There exists potential post-burial taphonomic roles for subsurface microorganisms.", "keyphrases": ["dinosaur bone", "organic material", "microbial community"]}
{"id": "10.1017/S009483730000868X", "title": "Approximate evolutionary stasis for bivalve morphology over millions of years: a multivariate, multilineage study", "abstract": "We have calculated rates of evolution for 19 lineages of Neogene bivalves over time intervals ranging from 1 ma to 17 ma. Our morphometric comparisons are based on 24 variables, for which we have made more than 43,000 individual measurements normalized for shell size. We initially assessed evolutionary changes in shape for 19 early Pliocene (4 ma old) species of bivalves by comparing these forms to their closest living relatives, which in 12 cases have traditonally been assigned to the same species. To make our study unbiased and comprehensive, we included all species that met certain predetermined guidelines and that offered suitable fossil material for measurement. We compared early Pliocene and Recent populations using (1) all 24 variables treated separately, (2) multivariate distance (Mahalanobis' D), based on the full set of variables, and (3) eigenshapes for shell outlines. For these comparisons, we used as a yardstick the same measures of morphologic distance applied to pairs of geographically separated Recent populations that belong to eight of the living species to which the fossil populations were compared. As it turns out, with minor exceptions, the distribution of morphologic distances between 4 ma old and Recent populations resembled the distribution of distances between conspecific Recent populations. We calculated net rates of evolution separating pairs of populations that belong to single lineages. For all intervals of time, the distribution of differences between population means for individual variables is remarkably similar to a comparable distribution representing the comparison of pairs of conspecific Recent populations from separate geographic regions. Because morphologic differences between populations do not vary greatly with evolutionary time, measured \u201crates\u201d of evolution, on the average, decrease with interval of measurement. Because these differences resemble intraspecific variability, however, the rates do not represent significant evolution. Evolution has followed a weak zigzag course, yielding only trivial net trends. The weak and reversible \u201ctrends\u201d that we measured yield net rates averaging less than 10 millidarwins, which is much lower than most rates previously reported for marine invertebrates (average ~200 millidarwins for a 1 ma interval and ~60 millidarwins for a 10 ma interval). We attribute this disparity (1) to the fact that most previously published rates have been calculated when a significant amount of evolution was recognized in advance (often for a poorly documented lineage) and (2) to the fact that most measured variables have represented nothing more than some measure of body size. We conclude that shape, as opposed to size, has been highly stable in bivalve evolution over millions of years and 106\u2013107 generations. We conclude that to characterize rates or evolution for any group of organisms, one must employ a large, unbiased sample of measurements for numerous well-documented lineages, and one must segregate data depicting shape from data depicting size.", "keyphrases": ["evolutionary stasis", "morphology", "million"]}
{"id": "10.1080/10635150802570809", "title": "The modified gap excess ratio (GER*) and the stratigraphic congruence of dinosaur phylogenies.", "abstract": "Palaeontologists routinely map their cladograms onto what is known of the fossil record. Where sister taxa first appear as fossils at different times, a ghost range is inferred to bridge the gap between these dates. Some measure of the total extent of ghost ranges across the tree underlies several indices of cladistic/stratigraphic congruence. We investigate this congruence for 19 independent, published cladograms of major dinosaur groups and report exceptional agreement between the phylogenetic and stratigraphic patterns, evidenced by sums of ghost ranges near the theoretical minima. This implies that both phylogenetic and stratigraphic data reflect faithfully the evolutionary history of dinosaurs, at least for the taxa included in this study. We formally propose modifications to an existing index of congruence (the gap excess ratio; GER), designed to remove a bias in the range of values possible with trees of different shapes. We also propose a more informative index of congruence--GER*--that takes account of the underlying distribution of sums of ghost ranges possible when permuting stratigraphic range data across the tree. Finally, we incorporate data on the range of possible first occurrence dates into our estimates of congruence, extending a procedure originally implemented with the modified Manhattan stratigraphic measure and GER to our new indices. Most dinosaur data sets maintain extremely high congruence despite such modifications.", "keyphrases": ["gap", "excess ratio", "stratigraphic congruence"]}
{"id": "paleo.004727", "title": "Unique near isometric ontogeny in the pterosaur\n Rhamphorhynchus\n suggests hatchlings could fly", "abstract": "Rhamphorhynchus muensteri is one of the best-known flying reptiles, represented by >130 well-preserved fossil specimens, from hatchlings to full adults. The life history of this pterosaur remains controversial as to when in ontogeny they took flight. Here, we assess the growth of these animals based on the lengths of numerous key elements. We show that changes in the skeletal anatomy of this reptile across its post-hatch size range reveal that R. muensteri exhibited overall near isometric growth in the wings, with slightly negative allometry in the humerus, radius and stronger negative allometry in the fourth metacarpal compared to body length, and slightly positive allometry in the second and third phalanges compared to body length. This pattern is near unique among flying vertebrates and suggests R. muensteri flew soon after hatching. In bats and birds, offspring do not typically fly until nearly adult sized. Conversely, near isometric growth in Rhamphorhynchus suggests it was a precocial flier and that individuals may have inhabited several sequential foraging niches over their lifespan, as some terrestrial and aquatic vertebrates do today. \u25a1 Bats, birds, ontogeny, precocial flight, pterosaurs.", "keyphrases": ["ontogeny", "pterosaur", "hatchling", "adult", "flight"]}
{"id": "paleo.005647", "title": "The role of experiments in investigating the taphonomy of exceptional preservation", "abstract": "In the last 20 years, much taphonomic experimentation has focused on the interpretation of exceptionally preserved fossils. Decay experiments have been used to interpret the features preserved in soft\u2010bodied fossils and to determine the sequence of character loss and its impact on phylogenetic position. Experiments on the impact of microbial communities on decay and mineralization have started to illuminate the processes involved in the fossilization of soft tissues, including embryos. The role of decay in promoting authigenic mineralization has been used to investigate the formation of Ediacaran macrofossils and concretions. Maturation experiments have shown how the constituents of animals and plants are transformed over time to a macromolecular material that converges on a similar stable composition. Other maturation experiments have explained how structural colours in fossils are altered from the original. A major area requiring investigation is the role of specific types of microbes in decay and their impact on sediment and pore water chemistry, as well as the environmental controls that determine their presence and level of activity. Microbial activity has received less attention than other factors in attempts to explain why the occurrence and nature of exceptional preservation varies in time and space through the fossil record.", "keyphrases": ["experiment", "exceptional preservation", "fossilization", "mineralization"]}
{"id": "10.1111/j.1469-7998.2011.00886.x", "title": "Body mass estimation in Early Miocene native South American ungulates: a predictive equation based on 3D landmarks", "abstract": "South American native ungulates include extinct taxa that evolved within the geographical context given by the isolation of South America during most of the Cenozoic. The ungulates (orders Notoungulata, Litopterna and Astrapotheria) of the Santa Cruz Formation (late Early Miocene) are particularly interesting for paleobiological studies due to their diversity, richness and quality of preservation of the specimens. The body mass estimation of extinct species is one of the basic biological attributes for paleobiological reconstructions. The most common way to estimate body mass from fossils is using linear regression. Here, we used geometric morphometric techniques in order to estimate their body mass. We used regressions based on centroid size of 3D craniomandibular landmark configurations, including extant ungulates (their size and ecological relatives). Cases were weighted to maximize the taxonomic evenness. A broad body size range was recorded. The highest predictive power is obtained with those functions derived from the highest taxonomic and ecological diversity. The highest taxonomic richness corresponds to masses below 100\u2009kg. Among Notoungulata, typotheres (Hegetotheriidae + Interatheriidae) vary from 1 to less than 10\u2009kg, while the smaller toxodontid reached 100\u2009kg and the larger 500\u2009kg. Litoptern proterotheriid body masses vary from 10 to 50\u2009kg, and macraucheniids surpass 100\u2009kg. The astrapotheres (Astrapotheria) reached (or even surpassed) 1000\u2009kg, being the only megamammal in the Santacrucian ungulate assemblage.", "keyphrases": ["early miocene", "ungulate", "body mass estimation"]}
{"id": "10.1126/sciadv.aay0456", "title": "Hyena paleogenomes reveal a complex evolutionary history of cross-continental gene flow between spotted and cave hyena", "abstract": "Westbury et al. reveal the genome-level evolutionary relationships between extinct cave and extant spotted hyena. The genus Crocuta (African spotted and Eurasian cave hyenas) includes several closely related extinct and extant lineages. The relationships among these lineages, however, are contentious. Through the generation of population-level paleogenomes from late Pleistocene Eurasian cave hyena and genomes from modern African spotted hyena, we reveal the cross-continental evolutionary relationships between these enigmatic hyena lineages. We find a deep divergence (~2.5 Ma) between African and Eurasian Crocuta populations, suggesting that ancestral Crocuta left Africa around the same time as early Homo. Moreover, we find discordance between nuclear and mitochondrial phylogenies and evidence for bidirectional gene flow between African and Eurasian Crocuta after the lineages split, which may have complicated prior taxonomic classifications. Last, we find a number of introgressed loci that attained high frequencies within the recipient lineage, suggesting some level of adaptive advantage from admixture.", "keyphrases": ["gene flow", "cave hyena", "genus crocuta", "late pleistocene", "hyena"]}
{"id": "10.1017/S0094837300016353", "title": "Tests and confidence intervals for a common upper endpoint in fossil taxa", "abstract": "Statistical inference about the upper and lower endpoints of the stratigraphic ranges of fossil taxa can be based on the pattern of finds. Strauss and Sadler (1989) described a test and confidence interval for a common upper or lower endpoint in two or more taxa. This approach is conservative, in the sense that it provides only an upper bound on the significance level. This paper describes and illustrates a test and confidence interval for which the significance level is known.", "keyphrases": ["confidence interval", "endpoint", "fossil taxa"]}
{"id": "paleo.009958", "title": "Recharacterization of ancient DNA miscoding lesions: insights in the era of sequencing-by-synthesis", "abstract": "Although ancient DNA (aDNA) miscoding lesions have been studied since the earliest days of the field, their nature remains a source of debate. A variety of conflicting hypotheses exist about which miscoding lesions constitute true aDNA damage as opposed to PCR polymerase amplification error. Furthermore, considerable disagreement and speculation exists on which specific damage events underlie observed miscoding lesions. The root of the problem is that it has previously been difficult to assemble sufficient data to test the hypotheses, and near-impossible to accurately determine the specific strand of origin of observed damage events. With the advent of emulsion-based clonal amplification (emPCR) and the sequencing-by-synthesis technology this has changed. In this paper we demonstrate how data produced on the Roche GS20 genome sequencer can determine miscoding lesion strands of origin, and subsequently be interpreted to enable characterization of the aDNA damage behind the observed phenotypes. Through comparative analyses on 390 965 bp of modern chloroplast and 131 474 bp of ancient woolly mammoth GS20 sequence data we conclusively demonstrate that in this sample at least, a permafrost preserved specimen, Type 2 (cytosine\u2192thymine/guanine\u2192adenine) miscoding lesions represent the overwhelming majority of damage-derived miscoding lesions. Additionally, we show that an as yet unidentified guanine\u2192adenine analogue modification, not the conventionally argued cytosine\u2192uracil deamination, underpins a significant proportion of Type 2 damage. How widespread these implications are for aDNA will become apparent as future studies analyse data recovered from a wider range of substrates.", "keyphrases": ["dna", "lesion", "overwhelming majority"]}
{"id": "10.1073/pnas.1503784112", "title": "Human population dynamics in Europe over the Last Glacial Maximum", "abstract": "Significance Despite its importance for understanding genetic, cultural, and linguistic evolution, prehistoric human population history has remained difficult to reconstruct. We show that the dynamics of the human population in Europe from 30,000 to 13,000 y ago can be simulated using ethnographic and paleoclimate data within the climate envelope modeling approach. Correspondence between the population simulation and archaeological data suggests that population dynamics were indeed driven by major climate fluctuations, with population size varying between 130,000 and 410,000 people. Although climate has been an important determinant of human population dynamics, the climatic conditions during the last glacial were not as harsh as is often presented, because even during the coldest phases, the climatically suitable area for humans covered 36% of Europe. The severe cooling and the expansion of the ice sheets during the Last Glacial Maximum (LGM), 27,000\u201319,000 y ago (27\u201319 ky ago) had a major impact on plant and animal populations, including humans. Changes in human population size and range have affected our genetic evolution, and recent modeling efforts have reaffirmed the importance of population dynamics in cultural and linguistic evolution, as well. However, in the absence of historical records, estimating past population levels has remained difficult. Here we show that it is possible to model spatially explicit human population dynamics from the pre-LGM at 30 ky ago through the LGM to the Late Glacial in Europe by using climate envelope modeling tools and modern ethnographic datasets to construct a population calibration model. The simulated range and size of the human population correspond significantly with spatiotemporal patterns in the archaeological data, suggesting that climate was a major driver of population dynamics 30\u201313 ky ago. The simulated population size declined from about 330,000 people at 30 ky ago to a minimum of 130,000 people at 23 ky ago. The Late Glacial population growth was fastest during Greenland interstadial 1, and by 13 ky ago, there were almost 410,000 people in Europe. Even during the coldest part of the LGM, the climatically suitable area for human habitation remained unfragmented and covered 36% of Europe.", "keyphrases": ["europe", "last glacial maximum", "human population dynamic"]}
{"id": "10.1029/94PA02928", "title": "Possible role of oceanic heat transport in early Eocene climate.", "abstract": "Increased oceanic heat transport has often been cited as a means of maintaining warm high-latitude surface temperatures in many intervals of the geologic past, including the early Eocene. Although the excess amount of oceanic heat transport required by warm high latitude sea surface temperatures can be calculated empirically, determining how additional oceanic heat transport would take place has yet to be accomplished. That the mechanisms of enhanced poleward oceanic heat transport remain undefined in paleoclimate reconstructions is an important point that is often overlooked. Using early Eocene climate as an example, we consider various ways to produce enhanced poleward heat transport and latitudinal energy redistribution of the sign and magnitude required by interpreted early Eocene conditions. Our interpolation of early Eocene paleotemperature data indicate that an approximately 30% increase in poleward heat transport would be required to maintain Eocene high-latitude temperatures. This increased heat transport appears difficult to accomplish by any means of ocean circulation if we use present ocean circulation characteristics to evaluate early Eocene rates. Either oceanic processes were very different from those of the present to produce the early Eocene climate conditions or oceanic heat transport was not the primary cause of that climate. We believe that atmospheric processes, with contributions from other factors, such as clouds, were the most likely primary cause of early Eocene climate.", "keyphrases": ["oceanic heat transport", "heat transport", "eocene climate"]}
{"id": "paleo.013034", "title": "Small-Bodied Humans from Palau, Micronesia", "abstract": "Newly discovered fossil assemblages of small bodied Homo sapiens from Palau, Micronesia possess characters thought to be taxonomically primitive for the genus Homo. Background Recent surface collection and test excavation in limestone caves in the rock islands of Palau, Micronesia, has produced a sizeable sample of human skeletal remains dating roughly between 940-2890 cal ybp. Principle Findings Preliminary analysis indicates that this material is important for two reasons. First, individuals from the older time horizons are small in body size even relative to \u201cpygmoid\u201d populations from Southeast Asia and Indonesia, and thus may represent a marked case of human insular dwarfism. Second, while possessing a number of derived features that align them with Homo sapiens, the human remains from Palau also exhibit several skeletal traits that are considered to be primitive for the genus Homo. Significance These features may be previously unrecognized developmental correlates of small body size and, if so, they may have important implications for interpreting the taxonomic affinities of fossil specimens of Homo.", "keyphrases": ["palau", "micronesia", "small-bodied human"]}
{"id": "10.1080/03115518.2015.967162", "title": "Palaeoenvironmental implications of the giant crocodylian Mourasuchus (Alligatoridae, Caimaninae) in the Yecua Formation (late Miocene) of Bolivia", "abstract": "Tineo, D.E., Bona, P., P\u00e9rez, L.M., Vergani, G.D., Gonz\u00e1lez, G., Poir\u00e9, D.G., Gasparini, Z.N. & Legarreta, P., 1.10.2014. Palaeoenvironmental implications of the giant crocodylian Mourasuchus (Alligatoridae, Caimaninae) in the Yecua Formation (late Miocene) of Bolivia. Alcheringa 39, xxx\u2013xxx. ISSN 0311-5518 Outcrops of the Yecua Formation (late Miocene) are exposed for approximately 230 m along the La Angostura section of the Pira\u00ed River (50 km southwest of Santa Cruz de la Sierra). These reveal massive (argillic palaeosols) and laminated (quiet-water lacustrine and marsh settings) mudstones interbedded with thin sandstones containing microfossils, molluscs and vertebrate remains. Significantly, the succession hosts a giant crocodylian, Mourasuchus (Alligatoridae, Caimaninae), which is represented by both skull and postcranial fragments found in association with freshwater turtles and fishes. Mourasuchus was distributed widely from the middle Miocene of Colombia to upper Miocene of Venezuela, Brazil and Argentina, suggesting connections between major fluvial systems and an active mechanism for dispersal of South American freshwater vertebrates during the Miocene. David Eric Tineo [tineo.d.e@gmail.com] and Daniel Gustavo Poir\u00e9 [dgpoire@yahoo.com.ar], CONICET\u2014Centro de Investigaciones Geol\u00f3gicas, Universidad Nacional de La Plata. Calle 1 (644), B1900FWA, La Plata, Argentina; Paula Bona [paulabona26@gmail.com] and Zulma Gasparini [zgaspari@fcnym.unlp.edu.ar], CONICET\u2014Divisi\u00f3n Paleontolog\u00eda Vertebrados, Museo de La Plata. Paseo del Bosque s/n, B1900FWA, La Plata, Argentina; Leandro Mart\u00edn P\u00e9rez [pilosaperez@gmail.com] CONICET\u2014Divisi\u00f3n Paleozoolog\u00eda Invertebrados, Museo de La Plata. Paseo del Bosque s/n, B1900FWA, La Plata, Argentina; Gustavo Dardo Vergani [gvergani@pluspetrol.net]\u2014Pluspetrol S.A. Lima (339), C1073AAG, Ciudad Aut\u00f3noma de Buenos Aires, Argentina; Gloria Gonz\u00e1lez Rigas [ggonzalez@pluspetrol.net]\u2014Pluspetrol Bolivia Corporation SA, Av. Grigot\u00e1 esq. Las Palmas, Santa Cruz de la Sierra, Bolivia; Pablo Legarreta [plegarreta@pluspetrol.net]\u2014Pluspetrol S.A. Lima (339), C1073AAG, Ciudad Aut\u00f3noma de Buenos Aires, Argentina.", "keyphrases": ["alligatoridae", "late miocene", "palaeoenvironmental implication"]}
{"id": "10.1111/pala.12428", "title": "Functional integration for enrolment constrains evolutionary variation of phacopid trilobites despite developmental modularity", "abstract": "Modularity and integration are variational properties expressed at various levels of the biological hierarchy. Mismatches among these levels, for example developmental modules that are integrated in a functional unit, could be informative of how evolutionary processes and trade\u2010offs have shaped organismal morphologies as well as clade diversification. In the present study, we explored the full, integrated and modular spaces of two developmental modules in phacopid trilobites, the cephalon and the pygidium, and highlight some differences among them. Such contrasts reveal firstly that evolutionary processes operating in the modular spaces are stronger in the cephalon, probably due to a complex regime of selection related to the numerous functions ensured by this module. Secondly, we demonstrate that the same pattern of covariation is shared among species, which also differentiate along this common functional integration. This common pattern might be the result of stabilizing selection acting on the enrolment and implying a coordinate variation between the cephalon and the pygidium in a certain direction of the morphospace. Finally, we noticed that Austerops legrandi differs slightly from other species in that its integration is partly restructured in the way the two modules interact. Such a divergence can result from the involvement of the cephalon in several vital functions that may have constrained the response of the features involved in enrolment and reorganized the covariation of the pygidium with the cephalon. Therefore, it is possible that important evolutionary trade\u2010offs between enrolment and other functions on the cephalon might have partly shaped the diversification of trilobites.", "keyphrases": ["phacopid trilobite", "trilobite", "functional integration"]}
{"id": "10.26879/920", "title": "Anomia-associated bryozoans from the upper Pliocene (Piacenzian) lower Tamiami Formation of Florida, USA", "abstract": "Commercial mining northeast of Sarasota, SW Florida (USA), since the 1960s has exposed Plio-Pleistocene marine shell beds of the Tamiami Formation, a complex sequence of mixed carbonate and siliciclastic beds containing a malacofauna that is a mixture of subtropical and temperate species. Material used for the current study consists of shells of the bivalve Anomia simplex d\u2019Orbigny, 1853 encrusted by bryozoans. The shells were collected from Units 10/11 of the lower Tamiami Formation, estimated as being late Pliocene (Piacenzian). This paper describes the bryozoan fauna associated with these \u2018jingle shells\u2019, which is of relatively low diversity, totaling 29 species, and comprises one cyclostome and 28 cheilostomes. Six cheilostome species are new: Micropora stellata sp. nov., Microporella sarasotaensis sp. nov., Microporella tamiamiensis sp. nov., Pourtalesella chiarae sp. nov., Spiniflabellum laurae sp. nov., and Trypostega composita sp. nov. Of the previously described species, six are extant and have western Atlantic distributions, while 12 species are known only from the fossil record. The bulk of the assemblage comprises a limited number of species represented by hundreds of colonies, while the remaining species are rare and represented by a single or a few colonies. Colonization of the shells is likely to have happened postmortem, considering the high percentage of valves encrusted on both surfaces. A large number of overgrowth interactions have been observed among the bryozoan colonies, thus this taxonomic revision is the necessary baseline for ecological analyses aiming to establish a ranking of species in a competitive hierarchy. Emanuela Di Martino. Department of Earth Sciences, Natural History Museum, Cromwell Road, SW7 5BD, London, United Kingdom. e.di-martino@nhm.ac.uk Paul D. Taylor. Department of Earth Sciences, Natural History Museum, Cromwell Road, SW7 5BD, London, United Kingdom. p.taylor@nhm.ac.uk Roger W. Portell. Division of Invertebrate Paleontology, Florida Museum of Natural History, University of Florida, Gainesville, FL 32611\u20137800, USA. portell@flmnh.ufl.edu http://zoobank.org/236D37F3-8616-4CF3-ADE7-54F84499D6EF Di Martino, Emanuela, Taylor, Paul D., and Portell, Roger W. 2019. Anomia-associated bryozoans from the upper Pliocene (Piacenzian) lower Tamiami Formation of Florida, USA. Palaeontologia Electronica 22.1.11A 1-65. https://doi.org/10.26879/920 palaeo-electronica.org/content/2019/2404-tamiami-formation-bryozoans Copyright: March 2019 Palaeontological Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ DI MARTINO, TAYLOR, & PORTELL: TAMIAMI FORMATION BRYOZOANS", "keyphrases": ["bryozoan", "upper pliocene", "florida"]}
{"id": "10.1130/2014.2505(04)", "title": "Effects of Deccan volcanism on paleoenvironment and planktic foraminifera: A global survey", "abstract": "Deccan volcanism, one of Earth\u2019s largest fl ood basalt provinces, erupted ~80% of its total volume (phase 2) during a relatively short time in the uppermost Maastrichtian paleomagnetic chron C29r and ended with the Cretaceous-Tertiary boundary mass extinction. Full biotic recovery in the marine realm was delayed at least 500 k.y. or until after the last Deccan eruptions in C29n (phase 3, 14% of the total Deccan volume). For over 30 yr, the mass extinction has been commonly attributed to the Chicxulub impact, and the delayed recovery remained an enigma. Here, we demonstrate that the two phases of Deccan volcanism can account for both the mass extinction and delayed marine recovery. In India, a direct correlation between Deccan eruptions (phase 2) and the mass extinction reveals that ~50% of the planktic foraminifer species gradually disappeared during volcanic eruptions prior to the fi rst of four lava megafl ows, reaching ~1500 km across India, and out to the Bay of Bengal. Another 50% disappeared after the fi rst megafl ow, and the mass extinction was complete with the last megafl ow. Throughout this interval, blooms of the disaster opportunist Guembelitria cretacea dominate shallow-marine assemblages in coeval intervals from India to the Tethys and the Atlantic Oceans to Texas. Similar high-stress environments dominated by blooms of Guembelitria and/or Globoconusa are observed correlative with Deccan volcanism phase 3 in the early Danian C29n, followed by full biotic recovery after volcanism ended. The mass extinction and high-stress conditions may be explained by the intense Deccan volcanism leading to rapid global warming and cooling in C29r and C29n, enhanced weathering, continental runoff, and ocean acidifi cation, resulting in a carbonate crisis in the marine environment. *jpunekar@princeton.edu Punekar, J., Mateo, P., and Keller, G., 2014, Effects of Deccan volcanism on paleoenvironment and planktic foraminifera: A global survey, in Keller, G., and Kerr, A.C., eds., Volcanism, Impacts, and Mass Extinctions: Causes and Effects: Geological Society of America Special Paper 505, p. 91\u2013116, doi:10.1130/2014.2505(04). For permission to copy, contact editing@geosociety.org. \u00a9 2014 The Geological Society of America. All rights reserved. on August 25, 2014 specialpapers.gsapubs.org Downloaded from", "keyphrases": ["volcanism", "paleoenvironment", "planktic foraminifera"]}
{"id": "paleo.000505", "title": "An Early Triassic gladius associated with soft tissue remains from Idaho, USA\u2014a squid-like coleoid cephalopod at the onset of Mesozoic Era", "abstract": "We describe an Olenekian (Early Triassic) \u201cfossil squid\u201d belonging to the oldest complex Mesozoic marine biota collected \nin the Lower Shale unit of the Lower Triassic Thaynes Group in Idaho, USA. The studied specimen shows a \ntapered structure embedded in a cylindrical soft body. Morphological, ultrastructural and geochemical features of the \nspecimen suggest that it corresponds to an internally-shelled cephalopod exhibiting a tapered micro-laminated gladius \nwith rachis, narrow median and lateral fields and a large conus; a pair of posterior large fin-supported cartilages and \nfins; ventral and dorsal mantle band-shape structures, the dorsal one being cartilaginous; mantle patches; a stomach \ncontaining undigested arm-hooks and sheet-like pieces of potential flooded ink. Coupled SEM/EDS analyses show \nthat (i) arm-hooks and ink were pseudomorphed by nanoparticles (less than 0.6 mm in diameter) of carbon, (ii) gladius \nand soft tissues were substituted by granules of calcium phosphate, (iii) cartilage canalicula\u2019s were partially filled with \ncalcium phosphate grains and crystals of Zn- and S-containing minerals. The specimen was hence probably fossilized \ndue to metabolism of P- and C-accumulating bacteria. Based on this specimen, Idahoteuthis parisiana Doguzhaeva and \nBrayard gen. et sp. nov. and Idahoteuthidae Doguzhaeva and Brayard fam. nov. are erected. This family is characterized \nby an elongated, cylindrical, dorsally cartilaginous muscular mantle; well-developed, about 0.2 mantle length, rounded \nanteriorly and acute posteriorly, fin-supported cartilages and similarly shaped two fins at conical mantle termination, \nand thin slender gladius with narrow median and lateral fields, rachis and breviconic conus. This family assumedly falls \nin Myopsida (Decabrachia). A streamlined body, large fin-supported cartilages and eroded arm-hooks in the stomach of \nIdahoteuthis Doguzhaeva and Brayard gen. nov. suggest that this was a maneuverable cannibal predator that dwelled in \nthe subequatorial shallow sea of the west coast of Pangaea.", "keyphrases": ["soft tissue", "idaho", "cephalopod"]}
{"id": "paleo.004367", "title": "Brain and eyes of Kerygmachela reveal protocerebral ancestry of the panarthropod head", "abstract": "Recent discoveries of fossil nervous tissue in Cambrian fossils have allowed researchers to trace the origin and evolution of the complex arthropod head and brain based on stem groups close to the origin of the clade, rather than on extant, highly derived members. Here we show that Kerygmachela from Sirius Passet, North Greenland, a primitive stem-group euarthropod, exhibits a diminutive (protocerebral) brain that innervates both the eyes and frontal appendages. It has been surmised, based on developmental evidence, that the ancestor of vertebrates and arthropods had a tripartite brain, which is refuted by the fossil evidence presented here. Furthermore, based on the discovery of eyes in Kerygmachela, we suggest that the complex compound eyes in arthropods evolved from simple ocelli, present in onychophorans and tardigrades, rather than through the incorporation of a set of modified limbs.", "keyphrases": ["eye", "kerygmachela", "brain"]}
{"id": "10.1017/S0094837300012938", "title": "Confidence intervals on stratigraphic ranges: partial relaxation of the assumption of randomly distributed fossil horizons", "abstract": "The equations for calculating classical confidence intervals on the end points of stratigraphic ranges are based on the restrictive assumption of randomly distributed fossil finds. Herein, a method is presented for calculating confidence intervals on the end-points of stratigraphic ranges that partially relaxes this assumption: the method will work for any continuous distribution of gap sizes, not just those generated by random processes. The price paid for the generality of the new approach is twofold: (1) there are uncertainties associated with the sizes of the confidence intervals, and (2) for large confidence values (e.g., 95%) a rich fossil record is required to place upper bounds on the corresponding confidence intervals. This new method is not universal; like the method for calculating classical confidence intervals it is based on the assumption that there is no correlation between gap size and stratigraphic position. The fossil record of the Neogene Caribbean bryozoan Metrarabdotos is analyzed with the new approach. The equations developed here, like those for classical confidence intervals, should not be applied to stratigraphic ranges based on discrete sampling regimes, such as those typically established from deep-sea drilling cores, though there are exceptions to this rule.", "keyphrases": ["stratigraphic range", "assumption", "confidence interval"]}
{"id": "paleo.009610", "title": "Diverse and complex developmental mechanisms of early Ediacaran embryo-like fossils from the Weng'an Biota, southwest China", "abstract": "The origin and early evolution of animal development remain among the many deep, unresolved problems in evolutionary biology. As a compelling case for the existence of pre-Cambrian animals, the Ediacaran embryo-like fossils (EELFs) from the Weng'an Biota (approx. 609 Myr old, Doushantuo Formation, South China) have great potential to cast light on the origin and early evolution of animal development. However, their biological implications can be fully realized only when their phylogenetic positions are correctly established, and unfortunately, this is the key problem under debate. As a significant feature of developmental biology, the cell division pattern (CDP) characterized by the dynamic spatial arrangement of cells and associated developmental mechanisms is critical to reassess these hypotheses and evaluate the diversity of the EELFs; however, their phylogenetic implications have not been fully realized. Additionally, the scarcity of fossil specimens representing late developmental stages with cell differentiation accounts for much of this debate too. Here, we reconstructed a large number of EELFs using submicron resolution X-ray tomographic microscopy and focused on the CDPs and associated developmental mechanisms as well as features of cell differentiation. Four types of CDPs and specimens with cell differentiation were identified. Contrary to the prevailing view, our results together with recent studies suggest that the diversity and complexity of developmental mechanisms documented by the EELFs are much higher than is often claimed. The diverse CDPs and associated development features including palintomic cleavage, maternal nutrition, asymmetric cell divisions, symmetry breaking, establishment of polarity or axis, spatial cell migration and differentiation constrain some, if not all, EELFs as total-group metazoans. This article is part of the theme issue \u2018The impact of Chinese palaeontology on evolutionary research\u2019.", "keyphrases": ["developmental mechanism", "embryo-like fossil", "weng'an biota"]}
{"id": "paleo.006937", "title": "New insights into the enigmatic Cretaceous family Spathiopterygidae (Hymenoptera: Diaprioidea)", "abstract": "The Cretaceous family Spathiopterygidae (Hymenoptera: Diaprioidea), containing five species in four genera, showed a wide distribution from the upper Barremian to the Turonian. We describe two new representatives of the family from the upper Albian San Just outcrop in the eastern Iberian Peninsula that correspond to Diameneura marveni gen. et sp. nov. Santer and Alvarez-Parra and to a female member of Mymaropsis turolensis Engel and Ortega-Blanco, 2013. The forewing venation of Diameneura marveni gen. et sp. nov. is interpreted, allowing an appropriate comparison for future descriptions. Furthermore, we provide a diagnosis for Mymaropsis baabdaensis since no diagnosis was proposed in the initial paper. We indicate the taphonomic characteristics of the newly described specimens, discuss the interrelationships of the family, and provide new insights about the sexual dimorphism and palaeobiology of spathiopterygids.", "keyphrases": ["family spathiopterygidae", "hymenoptera", "diaprioidea"]}
{"id": "paleo.003602", "title": "Computational fluid dynamics as a tool for testing functional and ecological hypotheses in fossil taxa", "abstract": "Computational fluid dynamics is a method for simulating fluid flows that has been widely used in engineering for decades, and which also has applications for studying function and ecology in fossil taxa. However, despite the possible benefits of this approach, computational fluid dynamics has been used only rarely in palaeontology to date. The theoretical basis underlying the technique is outlined and the main steps involved in carrying out computer simulations of fluid flows are detailed. I also describe previous studies that have applied the method to fossils and discuss their potential for informing future research directions in palaeontology. Computational fluid dynamics can enable large\u2010scale comparative analyses, as well as exacting tests of hypotheses related to the function and ecology of ancient organisms. In this way, it could transform our understanding of many extinct fossil groups.", "keyphrases": ["fossil taxa", "flow", "computational fluid dynamic", "cfd"]}
{"id": "10.1144/SP423.12", "title": "Greenhouse to icehouse: a biostratigraphic review of latest Devonian\u2013Mississippian glaciations and their global effects", "abstract": "Abstract The latest Devonian\u2013Mississippian interval records the long-term transition from Devonian greenhouse conditions into the Late Palaeozoic Ice Age (LPIA). This transition was punctuated by three short glaciation events in the latest Famennian, mid-Tournaisian and Visean stages, respectively. Primary evidence for glaciation is based on diamictite deposits and striated pavements in South America, Appalachia and Africa. The aim of this review is to assess the primary biostratigraphic and sedimentological data constraining diamictite deposits through this transition. These data are then compared to the wider record of eustasy, mass extinction and isotope stratigraphy in the lower palaeolatitudes. Precise age determinations are vital to integrate high- and low-palaeolatitude datasets, and to understand the glacial control on wider global changes. Palynological techniques currently provide the best biostratigraphic tool to date these glacial deposits and to correlate the effects of glaciation globally. This review highlights a high degree of uncertainty in the known history of early LPIA glaciation as much of the primary stratigraphic data are limited and/or unpublished. Future high-resolution stratigraphic studies are needed to constrain the history of glaciation both spatially and temporally through the latest Devonian and Mississippian.", "keyphrases": ["review", "glaciation", "mass extinction", "sea level fall", "gondwana"]}
{"id": "10.5194/gmd-10-3979-2017", "title": "The PMIP4 contribution to CMIP6 \u2013 Part 2: Two interglacials, scientific objective and experimental design for Holocene and Last Interglacial simulations", "abstract": "Two interglacial epochs are included in the suite of Paleoclimate Modeling Intercomparison Project (PMIP4) simulations in the Coupled Model Intercomparison Project (CMIP6). The experimental protocols for simulations of the mid-Holocene (midHolocene, 6000 years before present) and the Last Interglacial (lig127k, 127 000 years before present) are described here. These equilibrium simulations are designed to examine the impact of changes in orbital forcing at times when atmospheric greenhouse gas levels were similar to those of the preindustrial period and the continental configurations were almost identical to modern ones. These simulations test our understanding of the interplay between radiative forcing and atmospheric circulation, and the connections among large-scale and regional climate changes giving rise to phenomena such as land-sea contrast and high-latitude amplification in temperature changes, and responses of the monsoons, as compared to today. They also provide an opportunity, through carefully designed additional sensitivity experiments, to quantify the strength of atmosphere, ocean, cryosphere, and land-surface feedbacks. Sensitivity experiments are proposed to investigate the role of freshwater forcing in triggering abrupt climate changes within interglacial epochs. These feedback experiments naturally lead to a focus on climate evolution during interglacial periods, which will be examined through transient experiments. Analyses of the sensitivity simulations will also focus on interactions between extratropical and tropical circulation, and the relationship between changes in mean climate state and climate variability on annual to multi-decadal timescales. The comparative abundance of paleoenvironmental data and of quantitative climate reconstructions for the Holocene and Last In-terglacial make these two epochs ideal candidates for systematic evaluation of model performance, and such comparisons will shed new light on the importance of external feedbacks (e.g., vegetation, dust) and the ability of state-of-the-art models to simulate climate changes realistically.", "keyphrases": ["cmip6", "interglacial", "simulation", "present"]}
{"id": "10.1029/2019PA003665", "title": "Intense Hurricane Activity Over the Past 1500 Years at South Andros Island, The Bahamas", "abstract": "Hurricanes cause substantial loss of life and resources in coastal areas. Unfortunately, historical hurricane records are too short and incomplete to capture hurricane\u2010climate interactions on multi\u2010decadal and longer timescales. Coarse\u2010grained, hurricane\u2010induced deposits preserved in blue holes in the Caribbean can provide records of past hurricane activity extending back thousands of years. Here we present a high resolution record of intense hurricane events over the past 1500 years from a blue hole on South Andros Island on the Great Bahama Bank. This record is corroborated by shorter reconstructions from cores collected at two nearby blue holes. The record contains coarse\u2010grained event deposits attributable to known historical hurricane strikes within age uncertainties. Over the past 1500 years, South Andros shows evidence of four active periods of hurricane activity. None of these active intervals occurred in the past 163 years. We suggest that Intertropical Convergence Zone position modulates hurricane activity on the island based on a correlation with Cariaco Basin titanium concentrations. An anomalous gap in activity on South Andros Island in the early 13th century corresponds to a period of increased volcanism. The patterns of hurricane activity reconstructed from South Andros Island closely match those from the northeastern Gulf of Mexico but are anti\u2010phased with records from New England. We suggest that either changes in local environmental conditions (e.g., SSTs) or a northeastward shift in storm tracks can account for the increased activity in the western North Atlantic when the Gulf of Mexico and southeastern Caribbean are less active.", "keyphrases": ["hurricane activity", "south andros island", "event deposit", "local environmental condition"]}
{"id": "10.1111/j.1502-3931.1980.tb01025.x", "title": "Hyolitha: status of the phylum", "abstract": "Hyoliths are operculate calcareous shells found in Palaeozoic rocks. Runnegar et al. (1975) suggested that they be referred to a new phylum (Hyolitha) but Marek & Yochelson (1976) and Dzik (1978) preferred to regard them as an extinct class of the Mollusca. Since the hyolith cone is not easily homologized with the monoplacophoran shell, the exoskeletons of the shelled Mollusca and the Hyolitha appear to have developed independently. Reconstructions of the anatomy of hyoliths indicate that it is unlikely that both groups shared a common molluscan ancestor. Therefore, hyoliths are probably not molluscs. Previous reconstructions of articulated hyolithids have suggested that left and right appendages (helens) curved dorsally. Crushed articulated specimens from the Burgess Shale indicate that this conclusion is incorrect; hyoltthid helens seem to have curved ventrally when the animals were alive.", "keyphrases": ["phylum", "class", "hyolitha"]}
{"id": "10.1130/G39771.1", "title": "A new high-resolution chronology for the late Maastrichtian warming event: Establishing robust temporal links with the onset of Deccan volcanism", "abstract": "The late Maastrichtian warming event was defined by a global temperature increase of \u223c2.5\u20135 \u00b0C that occurred \u223c150\u2013300 k.y. before the Cretaceous-Paleogene (K-Pg) mass extinction. This transient warming event has traditionally been associated with a major pulse of Deccan Traps (west-central India) volcanism; however, large uncertainties associated with radiogenic dating methods have long hampered a definitive correlation. Here we present a new high-resolution, single species, benthic stable isotope record from the South Atlantic, calibrated to an updated orbitally tuned age model, to provide a revised chronology of the event, which we then correlate to the latest radiogenic dates of the main Deccan Traps eruption phases. Our data reveal that the initiation of deep-sea warming coincides, within uncertainty, with the onset of the main phase of Deccan volcanism, strongly suggesting a causal link. The onset of deep-sea warming is synchronous with a 405 k.y. eccentricity minimum, excluding a control by orbital forcing alone, although amplified carbon cycle sensitivity to orbital precession is evident during the greenhouse warming. A more precise understanding of Deccan-induced climate change paves the way for future work focusing on the fundamental role of these precursor climate shifts in the K-Pg mass extinction.", "keyphrases": ["maastrichtian warming event", "onset", "deccan volcanism"]}
{"id": "10.1645/13-485.1", "title": "A Retrospective Examination of Paleoparasitology and Its Establishment in the Journal of Parasitology", "abstract": "Abstract:\u2003 Volume 95 (2009) of the Journal of Parasitology represented a significant benchmark in the history of paleoparasitology when it received on the cover formal recognition as a topical area for publication. This retrospective examination chronicles the emergence of paleoparasitology, from its origins as an adjunct contribution to the study of prehistoric human populations to its modern expression as a sub-disciplinary interest. The aim of paleoparasitology is to elucidate the temporal and spatial dimensions of parasitism from the fossil record of human and non-human host populations.", "keyphrases": ["paleoparasitology", "journal", "parasitology"]}
{"id": "paleo.009235", "title": "Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary", "abstract": "Pterosaurs were the first vertebrates to evolve powered flight and the largest animals to ever take wing. The pterosaurs persisted for over 150 million years before disappearing at the end of the Cretaceous, but the patterns of and processes driving their extinction remain unclear. Only a single family, Azhdarchidae, is definitively known from the late Maastrichtian, suggesting a gradual decline in diversity in the Late Cretaceous, with the Cretaceous\u2013Paleogene (K-Pg) extinction eliminating a few late-surviving species. However, this apparent pattern may simply reflect poor sampling of fossils. Here, we describe a diverse pterosaur assemblage from the late Maastrichtian of Morocco that includes not only Azhdarchidae but the youngest known Pteranodontidae and Nyctosauridae. With 3 families and at least 7 species present, the assemblage represents the most diverse known Late Cretaceous pterosaur assemblage and dramatically increases the diversity of Maastrichtian pterosaurs. At least 3 families\u2014Pteranodontidae, Nyctosauridae, and Azhdarchidae\u2014persisted into the late Maastrichtian. Late Maastrichtian pterosaurs show increased niche occupation relative to earlier, Santonian-Campanian faunas and successfully outcompeted birds at large sizes. These patterns suggest an abrupt mass extinction of pterosaurs at the K-Pg boundary.", "keyphrases": ["pterosaur", "mass extinction", "first vertebrate", "late maastrichtian pterosaur"]}
{"id": "10.1111/evo.12562", "title": "The impact of shifts in marine biodiversity hotspots on patterns of range evolution: Evidence from the Holocentridae (squirrelfishes and soldierfishes)", "abstract": "One of the most striking biodiversity patterns is the uneven distribution of marine species richness, with species diversity in the Indo\u2010Australian Archipelago (IAA) exceeding all other areas. However, the IAA formed fairly recently, and marine biodiversity hotspots have shifted across nearly half the globe since the Paleogene. Understanding how lineages have responded to shifting biodiversity hotspots represents a necessary historic perspective on the formation and maintenance of global marine biodiversity. Such evolutionary inferences are often challenged by a lack of fossil evidence that provide insights into historic patterns of abundance and diversity. The greatest diversity of squirrelfishes and soldierfishes (Holocentridae) is in the IAA, yet these fishes also represent some of the most numerous fossil taxa in deposits of the former West Tethyan biodiversity hotspot. We reconstruct the pattern of holocentrid range evolution using time\u2010calibrated phylogenies that include most living species and several fossil lineages, demonstrating the importance of including fossil species as terminal taxa in ancestral area reconstructions. Holocentrids exhibit increased range fragmentation following the West Tethyan hotspot collapse. However, rather than originating within the emerging IAA hotspot, the IAA has acted as a reservoir for holocentrid diversity that originated in adjacent regions over deep evolutionary time scales.", "keyphrases": ["marine biodiversity", "range evolution", "holocentridae"]}
{"id": "10.3732/ajb.1000404", "title": "Angiosperm phylogeny: 17 genes, 640 taxa.", "abstract": "PREMISE OF THE STUDY\nRecent analyses employing up to five genes have provided numerous insights into angiosperm phylogeny, but many relationships have remained unresolved or poorly supported. In the hope of improving our understanding of angiosperm phylogeny, we expanded sampling of taxa and genes beyond previous analyses.\n\n\nMETHODS\nWe conducted two primary analyses based on 640 species representing 330 families. The first included 25260 aligned base pairs (bp) from 17 genes (representing all three plant genomes, i.e., nucleus, plastid, and mitochondrion). The second included 19846 aligned bp from 13 genes (representing only the nucleus and plastid).\n\n\nKEY RESULTS\nMany important questions of deep-level relationships in the nonmonocot angiosperms have now been resolved with strong support. Amborellaceae, Nymphaeales, and Austrobaileyales are successive sisters to the remaining angiosperms (Mesangiospermae), which are resolved into Chloranthales + Magnoliidae as sister to Monocotyledoneae + [Ceratophyllaceae + Eudicotyledoneae]. Eudicotyledoneae contains a basal grade subtending Gunneridae. Within Gunneridae, Gunnerales are sister to the remainder (Pentapetalae), which comprises (1) Superrosidae, consisting of Rosidae (including Vitaceae) and Saxifragales; and (2) Superasteridae, comprising Berberidopsidales, Santalales, Caryophyllales, Asteridae, and, based on this study, Dilleniaceae (although other recent analyses disagree with this placement). Within the major subclades of Pentapetalae, most deep-level relationships are resolved with strong support.\n\n\nCONCLUSIONS\nOur analyses confirm that with large amounts of sequence data, most deep-level relationships within the angiosperms can be resolved. We anticipate that this well-resolved angiosperm tree will be of broad utility for many areas of biology, including physiology, ecology, paleobiology, and genomics.", "keyphrases": ["gene", "angiosperm phylogeny", "eudicot"]}
{"id": "10.2174/1874213001003020001", "title": "Ecology and Palaeoecology: Two Approaches, One Objective", "abstract": "Despite what their names might suggest, ecology and palaeoecology have progressed historically as well separated disciplines. This unfortunate disjunction is analyzed here from a theoretical point of view. Among the factors that have facilitated the separation are: 1) the past-present dissociation characteristic of the human mind, 2) the diversity of fields of provenance of palaeoecologists, 3) the contrasting nature of the evidence and associated methodological differences, and 4) misunderstandings caused by the use of prefix palaeo-. The principle of uniformitarianism emphasizes that past, present and future are not discrete units but a time continuum through which species and communities flow, change and evolve; and that ecology and palaeoecology are only different approaches with a common objective, which is the ecological understanding of the biosphere. Therefore, a terminological clarification is needed. Ecology in a broad sense, includes inferences about the past (palaeoecology), present studies (neoecology or contemporary ecology) and future projections (predictive ecology). Palaeoecology is thus a means by which ecology studies the past using proxies. Other disciplines beginning with the prefix palaeo- (notably palaeoclimatology and palaeoenvironmental reconstruction) are not necessarily ecological. It is recommended that ecologists and palaeoecologists develop joint projects, and that palaeoecologists increase their participation in ecological journals, books and meetings. These collaborations will demonstrate that a palaeoecologist is not simply a palaeoscientist whose data may be of interest for ecology but is primarily an ecologist working on another time scale, with different methods.", "keyphrases": ["palaeoecology", "uniformitarianism", "ecology"]}
{"id": "paleo.001899", "title": "Bony\u2010toothed birds (Aves: Pelagornithidae) from the Middle Eocene of Belgium", "abstract": "Abstract:\u2002 We describe well\u2010preserved remains of the Pelagornithidae (bony\u2010toothed birds) from the middle Eocene of Belgium, including a sternum, pectoral girdle bones and humeri of a single individual. The specimens are tentatively assigned to Macrodontopteryx oweni Harrison and Walker, 1976 , which has so far only been known from the holotype skull and a referred proximal ulna. Another species, about two times larger, is represented by an incomplete humerus and tentatively identified as Dasornis emuinus ( Bowerbank, 1854 ). The fossils provide critical new data on the osteology of the pectoral girdle of bony\u2010toothed birds. For the first time, the sternum of one of the smaller species is preserved, and this bone exhibits a more plesiomorphic morphology than the recently described sternum of the giant Miocene taxon Pelagornis. The coracoid resembles that of the Diomedeidae (albatrosses) in overall morphology, but because bony\u2010toothed birds lack apomorphies of the Procellariiformes, the similarities are almost certainly owing to convergence. Bony\u2010toothed birds were often compared with the \u2018Pelecaniformes\u2019 by previous authors, who especially made comparisons with the Sulidae (gannets and boobies). However, the coracoid distinctly differs from that of extant \u2018pelecaniform\u2019 birds, and the plesiomorphic presence of a foramen nervi supracoracoidei as well as the absence of a well\u2010delimited articulation facet for the furcula supports a position outside the Suloidea, the clade to which the Sulidae belong.", "keyphrases": ["pelagornithidae", "middle eocene", "bony\u2010toothed bird"]}
{"id": "paleo.012019", "title": "Distinguishing African bovids using Zooarchaeology by Mass Spectrometry (ZooMS): New peptide markers and insights into Iron Age economies in Zambia", "abstract": "Assessing past foodways, subsistence strategies, and environments depends on the accurate identification of animals in the archaeological record. The high rates of fragmentation and often poor preservation of animal bones at many archaeological sites across sub-Saharan Africa have rendered archaeofaunal specimens unidentifiable beyond broad categories, such as \u201clarge mammal\u201d or \u201cmedium bovid\u201d. Identification of archaeofaunal specimens through Zooarchaeology by Mass Spectrometry (ZooMS), or peptide mass fingerprinting of bone collagen, offers an avenue for identification of morphologically ambiguous or unidentifiable bone fragments from such assemblages. However, application of ZooMS analysis has been hindered by a lack of complete reference peptide markers for African taxa, particularly bovids. Here we present the complete set of confirmed ZooMS peptide markers for members of all African bovid tribes. We also identify two novel peptide markers that can be used to further distinguish between bovid groups. We demonstrate that nearly all African bovid subfamilies are distinguishable using ZooMS methods, and some differences exist between tribes or sub-tribes, as is the case for Bovina (cattle) vs. Bubalina (African buffalo) within the subfamily Bovinae. We use ZooMS analysis to identify specimens from extremely fragmented faunal assemblages from six Late Holocene archaeological sites in Zambia. ZooMS-based identifications reveal greater taxonomic richness than analyses based solely on morphology, and these new identifications illuminate Iron Age subsistence economies c. 2200\u2013500 cal BP. While the Iron Age in Zambia is associated with the transition from hunting and foraging to the development of farming and herding, our results demonstrate the continued reliance on wild bovids among Iron Age communities in central and southwestern Zambia Iron Age and herding focused primarily on cattle. We also outline further potential applications of ZooMS in African archaeology.", "keyphrases": ["bovid", "mass spectrometry", "peptide marker", "africa"]}
{"id": "10.1111/joa.12918", "title": "Are endocasts good proxies for brain size and shape in archosaurs throughout ontogeny?", "abstract": "Cranial endocasts, or the internal molds of the braincase, are a crucial correlate for investigating the neuroanatomy of extinct vertebrates and tracking brain evolution through deep time. Nevertheless, the validity of such studies pivots on the reliability of endocasts as a proxy for brain morphology. Here, we employ micro\u2010computed tomography imaging, including diffusible iodine\u2010based contrast\u2010enhanced CT, and a three\u2010dimensional geometric morphometric framework to examine both size and shape differences between brains and endocasts of two exemplar archosaur taxa \u2013 the American alligator (Alligator mississippiensis) and the domestic chicken (Gallus gallus). With ontogenetic sampling, we quantitatively evaluate how endocasts differ from brains and whether this deviation changes during development. We find strong size and shape correlations between brains and endocasts, divergent ontogenetic trends in the brain\u2010to\u2010endocast correspondence between alligators and chickens, and a comparable magnitude between brain\u2013endocast shape differences and intraspecific neuroanatomical variation. The results have important implications for paleoneurological studies in archosaurs. Notably, we demonstrate that the pattern of endocranial shape variation closely reflects brain shape variation. Therefore, analyses of endocranial morphology are unlikely to generate spurious conclusions about large\u2010scale trends in brain size and shape. To mitigate any artifacts, however, paleoneurological studies should consider the lower brain\u2013endocast correspondence in the hindbrain relative to the forebrain; higher size and shape correspondences in chickens than alligators throughout postnatal ontogeny; artificially \u2018pedomorphic\u2019 shape of endocasts relative to their corresponding brains; and potential biases in both size and shape data due to the lack of control for ontogenetic stages in endocranial sampling.", "keyphrases": ["endocast", "brain size", "archosaur", "reliability"]}
{"id": "10.1111/nph.14470", "title": "Ancient plant DNA in lake sediments.", "abstract": "Contents 924 I. 925 II. 925 III. 927 IV. 929 V. 930 VI. 930 VII. 931 VIII. 933 IX. 935 X. 936 XI. 938 938 References 938 SUMMARY: Recent advances in sequencing technologies now permit the analyses of plant DNA from fossil samples (ancient plant DNA, plant aDNA), and thus enable the molecular reconstruction of palaeofloras. Hitherto, ancient frozen soils have proved excellent in preserving DNA molecules, and have thus been the most commonly used source of plant aDNA. However, DNA from soil mainly represents taxa growing a few metres from the sampling point. Lakes have larger catchment areas and recent studies have suggested that plant aDNA from lake sediments is a more powerful tool for palaeofloristic reconstruction. Furthermore, lakes can be found globally in nearly all environments, and are therefore not limited to perennially frozen areas. Here, we review the latest approaches and methods for the study of plant aDNA from lake sediments and discuss the progress made up to the present. We argue that aDNA analyses add new and additional perspectives for the study of ancient plant populations and, in time, will provide higher taxonomic resolution and more precise estimation of abundance. Despite this, key questions and challenges remain for such plant aDNA studies. Finally, we provide guidelines on technical issues, including lake selection, and we suggest directions for future research on plant aDNA studies in lake sediments.", "keyphrases": ["lake sediment", "ancient plant dna", "sedadna", "high taxonomic resolution"]}
{"id": "10.5479/si.00810266.79.1", "title": "Ontogeny, Intraspecific Variation, and Systematics of the Late Cambrian Trilobite Dikelocephalus", "abstract": "Hughes, Nigel C. Ontogeny, Intraspecific Variation, and Systematics of the Late Cambrian Trilobite Dikelocephalus. Smithsonian Contributions to Paleobiology, number 79,89 pages, 47 figures, 11 plates, 27 tables, 1994.\u2014Biometric analyses of well-localized specimens of the trilobite Dikelocephalus from the St. Lawrence Formation (Upper Cambrian), northern Mississippi Valley, suggest that all specimens belong to a single, highly variable morphospecies, D. minnesotensis. A complex pattern of ontogenetically-related and ontogeny-independent variation produced a mosaic of morphotypes, which show greater diversity than previously recorded within trilobite species. There is considerable variation within collections made from single beds. Variations of characters among collections are mosaic, and are clinal in some cases. Patterns of variation within Dikelocephalus cannot be related to lithofacies occurrence. There are no obvious temporal variations in D. minnesotensis within the St. Lawrence Formation, but some Dikelocephalus from the underlying Tunnel City Group may belong to a different taxon. The validity of this early taxon is questionable due to a lack of available material. The mosaic pattern of variation in Dikelocephalus mimics that documented at higher taxonomic levels in primitive libristomate trilobites, and helps explain difficulties in providing a workable taxonomy of primitive trilobites. Results caution proposition of evolutionary scenarios that do not take account of intraspecific variation. The recovery of dorsal shields of Dikelocephalus permits the first detailed reconstruction of the entire exoskeleton. The systematics of the genus is revised and twenty-five species are suppressed as junior synonyms of D. minnesotensis. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The trilobite Phacops rana Green. Library of Congress Cataloging-in-Publication Data Hughes, Nigel C. Ontogeny, intraspecific variation, and systematics of the Late Cambrian trilobite Dikelocephalus / Nigel C. Hughes p. cm. (Smithsonian contributions to paleobiology ; no. 79) Includes bibliographic references. 1. Dikelocephalus. 2. Paleontology-Cambrian. I. Title. II. Series. QE701.S56no. 79 [QE823.P79] 560 s-dc20 [562'.393] 94-28605 \u00ae The paper used in this publication meets the minimum requirements of the American National Standard for Permanence of Paper for Printed Library Materials Z39.48\u20141984.", "keyphrases": ["intraspecific variation", "cambrian trilobite dikelocephalus", "ontogeny"]}
{"id": "paleo.001789", "title": "Improved estimation of macroevolutionary rates from fossil data using a Bayesian framework", "abstract": "The estimation of origination and extinction rates and their temporal variation is central to understanding diversity patterns and the evolutionary history of clades. The fossil record provides the only direct evidence of extinction and biodiversity changes through time and has long been used to infer the dynamics of diversity changes in deep time. The software PyRate implements a Bayesian framework to analyze fossil occurrence data to estimate the rates of preservation, origination, and extinction while incorporating several sources of uncertainty. Building upon this framework, we present a suite of methodological advances including more complex and realistic models of preservation and the first likelihood-based test to compare the fit across different models. Further, we develop a new reversible jump Markov chain Monte Carlo algorithm to estimate origination and extinction rates and their temporal variation, which provides more reliable results and includes an explicit estimation of the number and temporal placement of statistically significant rate changes. Finally, we implement a new C++ library that speeds up the analyses by orders of magnitude, therefore facilitating the application of the PyRate methods to large data sets. We demonstrate the new functionalities through extensive simulations and with the analysis of a large data set of Cenozoic marine mammals. We compare our analytical framework against two widely used alternative methods to infer origination and extinction rates, revealing that PyRate decisively outperforms them across a range of simulated data sets. Our analyses indicate that explicit statistical model testing, which is often neglected in fossil-based macroevolutionary analyses, is crucial to obtain accurate and robust results.", "keyphrases": ["fossil data", "bayesian framework", "pyrate", "rate change", "diversification rate"]}
{"id": "paleo.002035", "title": "The morphology of the inner ear of squamate reptiles and its bearing on the origin of snakes", "abstract": "The inner ear morphology of 80 snake and lizard species, representative of a range of ecologies, is here analysed and compared to that of the fossil stem snake Dinilysia patagonica, using three-dimensional geometric morphometrics. Inner ear morphology is linked to phylogeny (we find here a strong phylogenetic signal in the data that can complicate ecological correlations), but also correlated with ecology, with Dinilysia resembling certain semi-fossorial forms (Xenopeltis and Cylindrophis), consistent with previous reports. We here also find striking resemblances between Dinilysia and some semi-aquatic snakes, such as Myron (Caenophidia, Homalopsidae). Therefore, the inner ear morphology of Dinilysia is consistent with semi-aquatic as well as semi-fossorial habits: the most similar forms are either semi-fossorial burrowers with a strong affinity to water (Xenopeltis and Cylindrophis) or amphibious, intertidal forms which shelter in burrows (Myron). Notably, Dinilysia does not cluster as closely with snakes with exclusively terrestrial or obligate burrowing habits (e.g. scolecophidians and uropeltids). Moreover, despite the above similarities, Dinilysia also occupies a totally unique morphospace, raising issues with linking it with any particular ecological category.", "keyphrases": ["inner ear", "squamate reptile", "snake", "ecology", "dinilysia"]}
{"id": "paleo.005253", "title": "The earliest annelids: Lower Cambrian polychaetes from the Sirius Passet Lagerst\u00e4tte, Peary Land, North Greenland", "abstract": "Apart from the Phyllopod Bed of the Burgess Shale (Middle Cambrian) polychaete annelids are practically unknown from any of the Cambrian Lagerst\u00e4tten. This is surprising both because their diversity in the Burgess Shale is considerable, while to date the Chengjiang Lagerst\u00e4tte which is equally impressive in terms of faunal diversity has no reliable records of any annelids. Here we describe, on the basis of about 40 specimens, Phragmochaeta canicularis gen. et sp. nov. from the Lower Cambrian Sirius Passet Lagerst\u00e4tte of Peary Land, North Greenland. This makes it by far the oldest known polychaete, with a likely age of lower to middle Atdabanian, The body consists of approximately 20 segments, each bearing notochaetae and neurochaetae. The former appeared to have formed a felt-like covering on the dorsum, whilst the neurochaetae projected obliquely to the longitudinal axis. Apart from minor differences in chaetal size at either end there is no other tagmosis. Details of the head are obscure, and presence of palps, tentacles and eyes are conjectural. Jaws appear to have been absent. The gut was straight, and flanked by massive longitudinal musculature. P. canicularis was evidently benthic, propelling itself on the neurochaetae, with the dorsal neurochaetae conferring protection. Its stratigraphic position and generalized appearance are consistent with P. canicularis being primitive, but the phylogenetic relationships within the polychaetes remain problematic, principally because of paucity of relevant morphological information.", "keyphrases": ["annelid", "polychaete", "north greenland", "conway morris"]}
{"id": "paleo.011998", "title": "The Neandertal genome and ancient DNA authenticity", "abstract": "Recent advances in high-thoughput DNA sequencing have made genome-scale analyses of genomes of extinct organisms possible. With these new opportunities come new difficulties in assessing the authenticity of the DNA sequences retrieved. We discuss how these difficulties can be addressed, particularly with regard to analyses of the Neandertal genome. We argue that only direct assays of DNA sequence positions in which Neandertals differ from all contemporary humans can serve as a reliable means to estimate human contamination. Indirect measures, such as the extent of DNA fragmentation, nucleotide misincorporations, or comparison of derived allele frequencies in different fragment size classes, are unreliable. Fortunately, interim approaches based on mtDNA differences between Neandertals and current humans, detection of male contamination through Y chromosomal sequences, and repeated sequencing from the same fossil to detect autosomal contamination allow initial large-scale sequencing of Neandertal genomes. This will result in the discovery of fixed differences in the nuclear genome between Neandertals and current humans that can serve as future direct assays for contamination. For analyses of other fossil hominins, which may become possible in the future, we suggest a similar \u2018boot-strap' approach in which interim approaches are applied until sufficient data for more definitive direct assays are acquired.", "keyphrases": ["neandertal genome", "genome", "dna sequence", "contamination"]}
{"id": "10.1093/isd/ixy008", "title": "Evolution, Diversification, and Biogeography of Grasshoppers (Orthoptera: Acrididae)", "abstract": "Abstract The grasshopper family Acrididae is one of the most diverse lineages within Orthoptera, including more than 6,700 valid species distributed worldwide. Grasshoppers are dominant herbivores, which have diversified into grassland, desert, semi-aquatic, alpine, and tropical forest habitats, and exhibit a wide array of morphological, ecological, and behavioral diversity. Nevertheless, the phylogeny of Acrididae as a whole has never been proposed. In this study, we present the first comprehensive phylogeny of Acrididae based on mitochondrial genomes and nuclear genes to test monophyly of the family and different subfamilies as well as to understand the evolutionary relationships among them. We recovered the monophyletic Acrididae and identified four major clades as well as several well-characterized subfamilies, but we also found that paraphyly is rampant across many subfamilies, highlighting the need for a taxonomic revision of the family. We found that Acrididae originated in the Paleocene of the Cenozoic period (59.3 million years ago) and, because the separation of South America and Africa predates the origin of the family, we hypothesize that the current cosmopolitan distribution of Acrididae was largely achieved by dispersal. We also inferred that the common ancestor of modern grasshoppers originated in South America, contrary to a popular belief that they originated in Africa, based on a biogeographical analysis. We estimate that there have been a number of colonization and recolonization events between the New World and the Old World throughout the diversification of Acrididae, and, thus, the current diversity in any given region is a reflection of this complex history.", "keyphrases": ["diversification", "orthoptera", "acrididae"]}
{"id": "paleo.006853", "title": "The exceptionally preserved Early Cretaceous \u201cMoqi Fauna\u201d from eastern Inner Mongolia, China, and its age relationship with the Jehol Biota", "abstract": "New fossil-bearing horizons at the Gezidong and Jiaxikou localities, eastern Inner Mongolia, referred to as the Moqi fossil bed, yield a diverse fossil assemblage coined herein as \"Moqi Fauna\". The Moqi Fauna provides important insights into the evolution of some vertebrate clades, such as frogs and salamanders, and their Early Cretaceous diversification. In this paper, we report an improved chronology of the Moqi fossil bed based on SIMS and high-precision CA-ID-IRMS U-Pb zircon analyses of three tuff samples from horizons that are interstratified with the fossil-bearing layer at two localities. The SIMS U-Pb dating method applied on zircons from three samples gave dates of 117.8 \u00b1 0.9/1.5 Ma, 117.7 \u00b1 1.0/1.5 Ma, and 118.3 \u00b1 1.2/1.7 Ma, respectively. Two highprecision CA-ID-IRMS U-Pb weighted mean 206 Pb/ 238 U ages of, 119.20 \u00b1 0.38/0.38/0.72 Ma and 118.67 \u00b1 0.13/ 0.14/0.28 Ma were also obtained. These findings indicate the age of the Moqi Fauna is ca. 119.20 Ma to 118.67 Ma. Comparison of the Moqi Fauna with the well-known Jehol Biota, as well as the Fuxin Biota of a slightly younger age, suggests that the Moqi Fauna was a distinct fauna which shows a potential link with the Jehol Biota.", "keyphrases": ["moqi fauna", "eastern inner mongolia", "jehol biota"]}
{"id": "10.1002/ajpa.22392", "title": "Hands of early primates.", "abstract": "Questions surrounding the origin and early evolution of primates continue to be the subject of debate. Though anatomy of the skull and inferred dietary shifts are often the focus, detailed studies of postcrania and inferred locomotor capabilities can also provide crucial data that advance understanding of transitions in early primate evolution. In particular, the hand skeleton includes characteristics thought to reflect foraging, locomotion, and posture. Here we review what is known about the early evolution of primate hands from a comparative perspective that incorporates data from the fossil record. Additionally, we provide new comparative data and documentation of skeletal morphology for Paleogene plesiadapiforms, notharctines, cercamoniines, adapines, and omomyiforms. Finally, we discuss implications of these data for understanding locomotor transitions during the origin and early evolutionary history of primates. Known plesiadapiform species cannot be differentiated from extant primates based on either intrinsic hand proportions or hand-to-body size proportions. Nonetheless, the presence of claws and a different metacarpophalangeal [corrected] joint form in plesiadapiforms indicate different grasping mechanics. Notharctines and cercamoniines have intrinsic hand proportions with extremely elongated proximal phalanges and digit rays relative to metacarpals, resembling tarsiers and galagos. But their hand-to-body size proportions are typical of many extant primates (unlike those of tarsiers, and possibly Teilhardina, which have extremely large hands). Non-adapine adapiforms and omomyids exhibit additional carpal features suggesting more limited dorsiflexion, greater ulnar deviation, and a more habitually divergent pollex than observed plesiadapiforms. Together, features differentiating adapiforms and omomyiforms from plesiadapiforms indicate increased reliance on vertical prehensile-clinging and grasp-leaping, possibly in combination with predatory behaviors in ancestral euprimates.", "keyphrases": ["primate", "posture", "hand"]}
{"id": "10.2307/1485353", "title": "Biogeographic history of Miocene calcareous nannoplankton and paleoceanography of the Atlantic Ocean", "abstract": "Biogeographic patterns of Miocene calcareous nannoplankton in the North and South Atlantic Ocean, the Caribbean Sea and the Gulf of Mexico are apparent from a Q-mode factor analysis of census data from 49 DSDP sites. In a total of 444 relatively well-preserved Miocene samples, 5 major and 1 minor (but relatively important) assemblages were recognized, most of which show distinct spatial and temporal distribution patterns. The major assemblages (identified by the dominant taxa) are the Dictyococcites minutus, Cyclicargolithus floridanus, Coccolithus pelagicus, Reticulofenestra pseudoumbilica-R. haqii, and Discoaster-Sphenolithus assemblages. Four of the major assemblages show distinct shifts through latitudes that are interpreted as a response to changing climate. Four warming and cooling cycles of 4 to 4.5 m.y. duration are identified in the Miocene. Both the paleobiogeographic and available isotopic data show the warming episode between 17 and 15.5 Ma and the cooling trend that followed, as well as the warming episode between 9 and 7 Ma, to have been particularly extreme in both Hemispheres, and probably of global extent. The sharp cooling centered at 1 5 Ma and the biogeographic changes at this time suggest this event to have been associated with the development of an extensive ice-cap on Antarctica. Biogeographic history of Miocene calcareous nannoplankton and paleoceanography of the Atlantic Ocean", "keyphrases": ["miocene", "atlantic ocean", "biogeographic history"]}
{"id": "paleo.011027", "title": "Dating the Diversification of the Major Lineages of Ascomycota (Fungi)", "abstract": "Establishing the dates for the origin and main diversification events in the phylogeny of Ascomycota is among the most crucial remaining goals in understanding the evolution of Fungi. There have been several analyses of divergence times in the fungal tree of life in the last two decades, but most have yielded contrasting results for the origin of the major lineages. Moreover, very few studies have provided temporal estimates for a large set of clades within Ascomycota. We performed molecular dating to estimate the divergence times of most of the major groups of Ascomycota. To account for paleontological uncertainty, we included alternative fossil constraints as different scenarios to enable a discussion of the effect of selection of fossils. We used data from 6 molecular markers and 121 extant taxa within Ascomycota. Our various \u2018relaxed clock\u2019 scenarios suggest that the origin and diversification of the Pezizomycotina occurred in the Cambrian. The main lineages of lichen\u2013forming Ascomycota originated at least as early as the Carboniferous, with successive radiations in the Jurassic and Cretaceous generating the diversity of the main modern groups. Our study provides new information about the timing of the main diversification events in Ascomycota, including estimates for classes, orders and families of both lichenized and non\u2013lichenized Ascomycota, many of which had not been previously dated.", "keyphrases": ["diversification", "ascomycota", "fungi"]}
{"id": "paleo.009186", "title": "Preliminary evidence for a 1000-year-old tsunami in the South China Sea", "abstract": "The risk of large, devastating tsunamis in the South China Sea and its surrounding coastal region is commonly underestimated or unrecognized due to the difficulty of differentiating tsunami from storm deposits. As a consequence, few convincing records have documented tsunami deposits in this region. Here we report preliminary evidence from Xisha Islands in the South China Sea for a large tsunami around AD 1024. Sand layers in lake sediment cores and their geochemical characteristics indicate a sudden deposition event around AD 1024, temporally consistent with a written record of a disastrous event characterized by high waves in AD 1076. Heavy coral and shell fossils, which are older than AD 1024, deposited more than 200 meters into the island, further support the occurrence of a high-energy event such as a tsunami or an unusually large storm. Our results underscore the importance of acknowledging and understanding the tsunami hazard in this area.", "keyphrases": ["tsunami", "south china sea", "preliminary evidence"]}
{"id": "paleo.003218", "title": "Miocene shift of European atmospheric circulation from trade wind to westerlies", "abstract": "The modern European climatic regime is peculiar, due to its unitary winter but diverse summer climates and a pronounced Mediterranean climate in the south. However, little is known on its evolution in the deep time.\nHere we reconstruct the European summer climate conditions in the Tortonian (11.62-7.246 Ma) using plant fossil assemblages from 75 well-dated sites across Europe. Our results clearly show that the Tortonian Europe mainly had humid to subhumid summers and no arid climate has been conclusively detected, indicating that the summer-dry Mediterranean-type climate has not yet been established along most of the Mediterranean coast at least by the Tortonian. More importantly, the reconstructed distribution pattern of summer precipitation reveals that the Tortonian European must have largely been controlled by westerlies, resulting in higher precipitation in the west and the lower in the east. The Tortonian westerly wind field appears to differ principally from the trade wind pattern of the preceding Serravallian (13.82-11.62 Ma), recently deduced from herpetofaunal fossils. Such a shift in atmospheric circulation, if ever occurred, might result from the development of ice caps and glaciers in the polar region during the Late Miocene global cooling, the then reorganization of oceanic circulation, and/or the Himalayan-Tibetan uplift.\nhe Late Miocene, a critical time period in Cenozoic climatic evolution, saw profound environmental changes and geological events, which together regulated the then climate distribution pattern 1,2 and gradually propagated to modern climate configuration 3, 4 . In North America a similar-to-modern climate was established as early as in the late Middle Miocene, marked by the onset of Great Plain landscape 5, 6 , while significantly intensified aridification in the vast Asian interior did not occur until the Late Miocene to Early Pliocene 3, 6, 7 . In Western Eurasia, however, although the Miocene climate has been extensively investigated [8] [9] [10] [11] , little is known about the early evolution of the regime, especially in regard to the hydrological dynamics and atmospheric circulation 6, 11, 12 .\nThe modern Europe experiences a prevalence of westerlies in winter, while the summer climates are highly diverse, mainly consisting of a maritime climate along the western coast with evenly dispersed precipitation throughout the year, a Mediterranean climate in the south with dry summers, and a subhumid-semiarid continental climate to the east 13, 14 . Such a pattern is jointly controlled by the westerlies and the seasonal shift of Azores subtropical high between ,30u N in winter and ,35u N in summer 4, 14 . By contrast, during the Serravallian (late Middle Miocene; 13.82-11.62 Ma), the distribution of summer precipitation suggests that Europe was likely dominated by a trade wind system flowing from the northeast to southwest 15 . Therefore a dramatic shift of the wind field must have occurred between the Serravallian and present. However, neither proxy data nor modelling results have ever evidenced this upheaval before. Here we reconstruct the Tortonian (early Late Miocene; 11.62-7.246 Ma) hydrological dynamics of Europe using palaeobotanical proxy data supplemented by modelling experiments, with a specific focus on the summer condition, to infer the wind direction and consequently the prevailing atmospheric circulation patterns following the Serravallian. Our results reveal a dramatic transition in atmospheric circulation that the so called Serravallian trade winds 15 gave way to the Tortonian westerlies that predominate over Western Eurasia.\nTortonian summer hydrological distribution. The estimated means of warmest month precipitations (WMP) of the Tortonian Europe range between ,67 mm and ,164 mm, with corresponding warmest month temperatures (WMT) between 21.2uC and 27.8uC (Fig. 1A , 1B; and Supplementary Information Table 1 for complete data ranges). Locations with high WMPs are found in West Europe, except for the southerly coastal", "keyphrases": ["atmospheric circulation", "trade wind", "westerly"]}
{"id": "paleo.008278", "title": "Hard tissue anatomy of the cranial joints in Sphenodon (Rhynchocephalia): sutures, kinesis, and skull mechanics", "abstract": "The anatomy of the extant lepidosaur Sphenodon (New Zealand tuatara) has been extensively examined by palaeontologists and comparative anatomists because of its phylogenetic status as the only living member of the Rhynchocephalia. It is also of interest because of its sophisticated feeding apparatus and a prooral (anteriorly directed) mode of shearing used to rip food apart. However, despite several detailed descriptions of the skull, the three-dimensional relationship between individual bones of the skull has generally been ignored. Here we provide the first joint by joint description of the hard tissue anatomy for almost every cranial suture in the skull of Sphenodon. This survey shows that most joints involve either abutments (e.g., along the midline) or extensive overlaps (e.g., more peripheral areas) but there are others that are heavily interlocked (e.g., postorbital-postfrontal) or involve a notable amount of soft tissue (e.g., vomer-premaxilla). There is variation in facet surface texture (e.g., smooth, ridged, pitted) but extensive interdigitation is uncommon and generally restricted to one plane. The joints do not appear suited to promote the marked intracranial movement reported in lizards such as geckos. However, it is possible that the base of the premaxillae would have been able to pivot slightly when loaded or impacted by the lower jaw during shearing. The extensive overlapping joints probably serve to maximise the surface area available for soft tissues that can dissipate and redistribute stress while maintaining the rigidity of the skull. These joints are larger in adults which bite more forcefully and may feed on harder prey.", "keyphrases": ["sphenodon", "rhynchocephalia", "skull", "hard tissue anatomy"]}
{"id": "paleo.001176", "title": "Evolution of trilobite enrolment during the Great Ordovician Biodiversification Event: insights from kinematic modelling", "abstract": "The Great Ordovician Biodiversification Event (GOBE) represents a diversification at lower taxonomic levels of most body plans that had appeared during the Cambrian explosion. Among trilobites, several novelties related to enrolment evolved during the GOBE. A kinematic analysis by means of 3D modelling of some new enrolment types shows no relationship with those of the Cambrian trilobites. While some structures emerged for the first time in Ordovician trilobites (e.g. articulations and panderian organs), other structures (e.g. anterior and posterior arch in head and tail) appear earlier in Cambrian trilobites. Our results suggest that the evolution of some groups was clearly rooted in the Cambrian explosion while others clearly appeared during the GOBE.", "keyphrases": ["enrolment", "gobe", "novelty"]}
{"id": "paleo.009129", "title": "A Paleolatitude Calculator for Paleoclimate Studies", "abstract": "Realistic appraisal of paleoclimatic information obtained from a particular location requires accurate knowledge of its paleolatitude defined relative to the Earth\u2019s spin-axis. This is crucial to, among others, correctly assess the amount of solar energy received at a location at the moment of sediment deposition. The paleolatitude of an arbitrary location can in principle be reconstructed from tectonic plate reconstructions that (1) restore the relative motions between plates based on (marine) magnetic anomalies, and (2) reconstruct all plates relative to the spin axis using a paleomagnetic reference frame based on a global apparent polar wander path. Whereas many studies do employ high-quality relative plate reconstructions, the necessity of using a paleomagnetic reference frame for climate studies rather than a mantle reference frame appears under-appreciated. In this paper, we briefly summarize the theory of plate tectonic reconstructions and their reference frames tailored towards applications of paleoclimate reconstruction, and show that using a mantle reference frame, which defines plate positions relative to the mantle, instead of a paleomagnetic reference frame may introduce errors in paleolatitude of more than 15\u00b0 (>1500 km). This is because mantle reference frames cannot constrain, or are specifically corrected for the effects of true polar wander. We used the latest, state-of-the-art plate reconstructions to build a global plate circuit, and developed an online, user-friendly paleolatitude calculator for the last 200 million years by placing this plate circuit in three widely used global apparent polar wander paths. As a novelty, this calculator adds error bars to paleolatitude estimates that can be incorporated in climate modeling. The calculator is available at www.paleolatitude.org. We illustrate the use of the paleolatitude calculator by showing how an apparent wide spread in Eocene sea surface temperatures of southern high latitudes may be in part explained by a much wider paleolatitudinal distribution of sites than previously assumed.", "keyphrases": ["paleolatitude calculator", "paleoclimate studies", "location"]}
{"id": "10.2110/palo.2005.p05-122r", "title": "BODY SIZE ESTIMATES FROM THE LITERATURE: UTILITY AND POTENTIAL FOR MACROEVOLUTIONARY STUDIES", "abstract": "Abstract Images in the monographic literature represent an important but relatively untapped resource for paleontologists. In particular, they could provide vast amounts of body size data. It is possible, however, that images of specimens represent a biased sample of the fossil record. Thus, the quality of these data must be assessed before body size estimates from the literature can be used in analyses. Two complementary datasets were constructed for a group of bivalve and brachiopod species from the Paleozoic and the Cenozoic. The monograph dataset consisted of length measurements taken from all unique images of a species in a monograph. The counterpart bulk dataset consisted of comparable measurements taken from a set (n > 10) of bulk-collected specimens of the same species acquired from the same locality as those figured in the monograph. These paired datasets were used to assess the quality of monographic data. Bias direction and magnitude were assessed by using the bulk sample of a species as an estimate of its underlying size-frequency distribution. Bias was estimated for each monographed specimen by calculating its percentile-value in relation to the size-frequency distribution for that species. All species groups had mean values within the 70th to 85th percentile range, indicating a significant bias toward monograph specimens that are larger than the mean of the bulk sample. The consistency of bias was evaluated by comparing the monograph sample mean to the bulk sample mean for each species. When compared in bivariate scatter plots, all species groups yielded significant regression lines with slopes near unity, indicating highly consistent, yet predictable, bias in each case. This trend persisted when the data were grouped taxonomically, geographically, or by year of monograph publication. These results indicate that size measurements of monographed specimens of bivalves and brachiopods consistently record similar size classes for most species. This bias is easy to remove and doing so renders size data from images in monographs useful for macroevolutionary studies of body size.", "keyphrases": ["literature", "macroevolutionary study", "body size"]}
{"id": "paleo.004017", "title": "Molecular composition and ultrastructure of Jurassic paravian feathers", "abstract": "Feathers are amongst the most complex epidermal structures known, and they have a well-documented evolutionary trajectory across non-avian dinosaurs and basal birds. Moreover, melanosome-like microbodies preserved in association with fossil plumage have been used to reconstruct original colour, behaviour and physiology. However, these putative ancient melanosomes might alternatively represent microorganismal residues, a conflicting interpretation compounded by a lack of unambiguous chemical data. We therefore used sensitive molecular imaging, supported by multiple independent analytical tests, to demonstrate that the filamentous epidermal appendages in a new specimen of the Jurassic paravian Anchiornis comprise remnant eumelanosomes and fibril-like microstructures, preserved as endogenous eumelanin and authigenic calcium phosphate. These results provide novel insights into the early evolution of feathers at the sub-cellular level, and unequivocally determine that melanosomes can be preserved in fossil feathers.", "keyphrases": ["jurassic", "feather", "melanosome"]}
{"id": "10.1098/rstb.2015.0247", "title": "The evolution of body size and shape in the human career", "abstract": "Body size is a fundamental biological property of organisms, and documenting body size variation in hominin evolution is an important goal of palaeoanthropology. Estimating body mass appears deceptively simple but is laden with theoretical and pragmatic assumptions about best predictors and the most appropriate reference samples. Modern human training samples with known masses are arguably the \u2018best\u2019 for estimating size in early bipedal hominins such as the australopiths and all members of the genus Homo, but it is not clear if they are the most appropriate priors for reconstructing the size of the earliest putative hominins such as Orrorin and Ardipithecus. The trajectory of body size evolution in the early part of the human career is reviewed here and found to be complex and nonlinear. Australopith body size varies enormously across both space and time. The pre-erectus early Homo fossil record from Africa is poor and dominated by relatively small-bodied individuals, implying that the emergence of the genus Homo is probably not linked to an increase in body size or unprecedented increases in size variation. Body size differences alone cannot explain the observed variation in hominin body shape, especially when examined in the context of small fossil hominins and pygmy modern humans. This article is part of the themed issue \u2018Major transitions in human evolution\u2019.", "keyphrases": ["body size", "human career", "human evolution"]}
{"id": "paleo.007402", "title": "Eocene Pachynolophinae (Perissodactyla, Palaeotheriidae) from China, and their palaeobiogeographical implications", "abstract": "The Eocene perissodactyl family Palaeotheriidae has traditionally been considered to be a nearly endemic European group within Equoidea, but a few palaeotheres have been reported from Asia. Here, I reanalyse a maxilla containing M1\u20133 from the Lunan Basin, Yunnan Province, China. This element was initially assigned to a new tapiromorph species, Lophialetes yunnanensis, but is here placed in a new genus Lophiohippus within Pachynolophinae based mainly on the absence of mesostyles, the strongly oblique metalophs, the strong development of lophodonty, parastyles overlapping metastyles of preceding teeth and situated mesial to the paracone, and the fact that M3 is longer than wide and has a large and buccally deflected metastyle. Lophiohippus differs from European Anchilophus and Paranchilophus in that the parastyles are situated mesial or even slightly lingual, rather than mesiobuccal, to the paracones, and M3 is markedly relatively larger than M1. I further reanalyse Qianohippus magicus from the Shinao Basin of Guizhou Province, China, in which the complete dentition is known. Qianohippus is characterized by a molariform P2 and non\u2010molariform P3\u20134; a relatively high degree of lophodonty; the absence of mesostyles; an angular bending in the protoloph on P3\u2010M3 and the metaloph on M1\u20133 at the paraconule and metaconule, respectively; and weakly developed \u2018metastylid\u2019 on the lower cheek teeth. A cladistic analysis supports a close relationship between Lophiohippus yunnanensis and Paranchilophus, and suggests that Qianohippus is closely related to some derived pachynolophs. The appearance of the pachynolophins Lophiohippus and Qianohippus in China supports the existence of a biogeographical connection between Europe and Asia in the Middle\u2010Late Eocene, and the dispersal route was probably along the Tethyan microcontinents in the south.", "keyphrases": ["palaeotheriidae", "china", "palaeothere"]}
{"id": "paleo.009221", "title": "Resequencing 545 ginkgo genomes across the world reveals the evolutionary history of the living fossil", "abstract": "As Charles Darwin anticipated, living fossils provide excellent opportunities to study evolutionary questions related to extinction, competition, and adaptation. Ginkgo (Ginkgo biloba L.) is one of the oldest living plants and a fascinating example of how people have saved a species from extinction and assisted its resurgence. By resequencing 545 genomes of ginkgo trees sampled from 51 populations across the world, we identify three refugia in China and detect multiple cycles of population expansion and reduction along with glacial admixture between relict populations in the southwestern and southern refugia. We demonstrate multiple anthropogenic introductions of ginkgo from eastern China into different continents. Further analyses reveal bioclimatic variables that have affected the geographic distribution of ginkgo and the role of natural selection in ginkgo\u2019s adaptation and resilience. These investigations provide insights into the evolutionary history of ginkgo trees and valuable genomic resources for further addressing various questions involving living fossil species.", "keyphrases": ["ginkgo", "world", "evolutionary history"]}
{"id": "10.1073/pnas.1216774109", "title": "Irreconcilable differences between stratigraphy and direct dating cast doubts upon the status of Tam Pa Ling fossil", "abstract": "The specific evolutionary history of anatomically modern humans (AMHs) and their regional variation throughout the course of the Pleistocene form two major areas of paleoanthropological research, particularly in poorly documented regions (1). Unfortunately, uncertainties still surround the chronology of the emergence of AMHs and their initial occupation of Southeast Asia. In this context, although the recently published modern human cranium from Tam Pa Ling, Laos (2) (i.e., TPL1), provides new anatomical data concerning AMHs in Southeast Asia, the authors\u2019 interpretation of TPL1 as \u201cthe earliest skeletal evidence for fully modern humans in mainland Southeast Asia\u201d is not supported by their stratigraphic data. In the absence of additional information, TPL1, although directly dated to 63.6 ka, appears to have been found in an intrusive position within sediment dated to between 46 ka (optically stimulated luminescence) and 2.77 ka [accelerator mass spectrometry (AMS) 14C; Fig. 1]. If the base of the stratigraphic sequence dates to between 48 ka (optically stimulated luminescence) and 49.2 ka (AMS 14C), how could sediment \u223c2 m above be as old as 51.4 ka (AMS 14C) if the main sedimentary process at work is claimed to be \u201crelatively slow, low-energy slopewash transport\u201d? Similarly, what is the rationale for stating that \u201cthe fossils were buried no later than 46 ka and no earlier than 47 to 51 ka\u201d? In the absence of any supporting explanation for this \u201creverse stratigraphy,\u201d the older dates produced for the top of the 2- to 3-m layer should be regarded with suspicion. Hence, contrary to the authors' assertion that TPL1 has a \u201cminimum secured age of 46 ka and a maximum age of \u223c63 ka\u201d, the published stratigraphy, if correct, indicates that the TPL1 specimen is no older than 46 ka. TPL1\u2019s status as \u201cthe earliest well-dated modern human fossil east of the Jordan Valley\u201d also appears weak compared with the Liujiang specimen dated to \u223c153 ka (3), the Callao Cave fossil in the Philippines dated to 67 ka (4), and, above all, the \u223c100 ka modern fossil from Zhirendong (5), discovered only 484 km northeast of Tam Pa Ling in Southern China. Direct dating methods are increasingly applied to human fossils because stratigraphic associations between human fossils and archaeological remains and/or deposits do not always exist. However, the dating of the fossils themselves should by no means be considered independently of contextual multidisciplinary data that form the basis of modern archaeology. In summary, given the irreconcilable differences between the stratigraphy and direct dating, the TPL1 specimen is not demonstrably the earliest modern human in Southeast Asia.", "keyphrases": ["stratigraphy", "status", "irreconcilable difference"]}
{"id": "paleo.008841", "title": "New evidence for the protoconodont origin of chaetognaths", "abstract": "An earlier hypothesis concerning the origin of chaetognaths from protoconodonts found additional support in new discoveries and in recent structural, chemical and molecular investigations. The new findings show that the head armature of protoconodonts was composed not only of grasping spines but also of much smaller spicules corresponding in size and shape to the chaetognath teeth. Grasping spines of protoconodonts were originally built mainly of an organic substance. Their original composition was changed by secondary phosphatisation. The thickest layer of the protoconodont spines was originally constructed of organic fibrils, similar to those in the corresponding layer of chaetognaths. Recent molecular investigations show that the chaetognath lineage separated in the early stage of metazoan radiation, which fits the presented hypothesis. Described are some previously unknown structural details of chaetognath grasping spines, including composition of the outer layer and the origin of their distinctive tips. ", "keyphrases": ["protoconodont", "chaetognath", "spine", "rock"]}
{"id": "paleo.011408", "title": "Novel high-resolution characterization of ancient DNA reveals C > U-type base modification events as the sole cause of post mortem miscoding lesions", "abstract": "Ancient DNA (aDNA) research has long depended on the power of PCR to amplify trace amounts of surviving genetic material from preserved specimens. While PCR permits specific loci to be targeted and amplified, in many ways it can be intrinsically unsuited to damaged and degraded aDNA templates. PCR amplification of aDNA can produce highly-skewed distributions with significant contributions from miscoding lesion damage and non-authentic sequence artefacts. As traditional PCR-based approaches have been unable to fully resolve the molecular nature of aDNA damage over many years, we have developed a novel single primer extension (SPEX)-based approach to generate more accurate sequence information. SPEX targets selected template strands at defined loci and can generate a quantifiable redundancy of coverage; providing new insights into the molecular nature of aDNA damage and fragmentation. SPEX sequence data reveals inherent limitations in both traditional and metagenomic PCR-based approaches to aDNA, which can make current damage analyses and correct genotyping of ancient specimens problematic. In contrast to previous aDNA studies, SPEX provides strong quantitative evidence that C > U-type base modifications are the sole cause of authentic endogenous damage-derived miscoding lesions. This new approach could allow ancient specimens to be genotyped with unprecedented accuracy.", "keyphrases": ["ancient dna", "lesion", "pcr", "genetic material", "quantitative evidence"]}
{"id": "10.1098/rsta.2008.0200", "title": "The past is a guide to the future? Comparing Middle Pliocene vegetation with predicted biome distributions for the twenty-first century", "abstract": "During the Middle Pliocene, the Earth experienced greater global warmth compared with today, coupled with higher atmospheric CO2 concentrations. To determine the extent to which the Middle Pliocene can be used as a \u2018test bed\u2019 for future warming, we compare data and model-based Middle Pliocene vegetation with simulated global biome distributions for the mid- and late twenty-first century. The best agreement is found when a Middle Pliocene biome reconstruction is compared with a future scenario using 560\u200appmv atmospheric CO2. In accordance with palaeobotanical data, all model simulations indicate a generally warmer and wetter climate, resulting in a northward shift of the taiga\u2013tundra boundary and a spread of tropical savannahs and woodland in Africa and Australia at the expense of deserts. Our data\u2013model comparison reveals differences in the distribution of polar vegetation, which indicate that the high latitudes during the Middle Pliocene were still warmer than its predicted modern analogue by several degrees. However, our future scenarios do not consider multipliers associated with \u2018long-term\u2019 climate sensitivity. Changes in global temperature, and thus biome distributions, at higher atmospheric CO2 levels will not have reached an equilibrium state (as is the case for the Middle Pliocene) by the end of this century.", "keyphrases": ["middle pliocene vegetation", "biome distribution", "century"]}
{"id": "10.5194/bg-7-869-2010", "title": "Incorporation of Mg and Sr in calcite of cultured benthic foraminifera: impact of calcium concentration and associated calcite saturation state", "abstract": "Abstract. We investigated the effect of the calcium concentration in seawater and thereby the calcite saturation state (\u03a9) on the magnesium and strontium incorporation into benthic foraminiferal calcite under laboratory conditions. For this purpose individuals of the shallow-water species Heterostegina depressa (precipitating high-Mg calcite, symbiont-bearing) and Ammonia tepida (low-Mg calcite, symbiont-barren) were cultured in media under a range of [Ca2+], but similar Mg/Ca ratios. Trace element/Ca ratios of newly formed calcite were analysed with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and normalized to the seawater elemental composition using the equation DTE=(TE/Cacalcite)/(TE/Caseawater). The culturing study shows that DMg of A. tepida significantly decreases with increasing \u03a9 at a gradient of \u22124.3\u00d710\u22125 per \u03a9 unit. The DSr value of A. tepida does not change with \u03a9, suggesting that fossil Sr/Ca in this species may be a potential tool to reconstruct past variations in seawater Sr/Ca. Conversely, DMg of H. depressa shows only a minor decrease with increasing \u03a9, while DSr increases considerably with \u03a9 at a gradient of 0.009 per \u03a9 unit. The different responses to seawater chemistry of the two species may be explained by a difference in the calcification pathway that is, at the same time, responsible for the variation in the total Mg incorporation between the two species. Since the Mg/Ca ratio in H. depressa is 50\u2013100 times higher than that of A. tepida, it is suggested that the latter exhibits a mechanism that decreases the Mg/Ca ratio of the calcification fluid, while the high-Mg calcite forming species may not have this physiological tool. If the dependency of Mg incorporation on seawater [Ca2+] is also valid for deep-sea benthic foraminifera typically used for paleostudies, the higher Ca concentrations in the past may potentially bias temperature reconstructions to a considerable degree. For instance, 25 Myr ago Mg/Ca ratios in A. tepida would have been 0.2 mmol/mol lower than today, due to the 1.5 times higher [Ca2+] of seawater, which in turn would lead to a temperature underestimation of more than 2 \u00b0C.", "keyphrases": ["benthic foraminifera", "foraminifera", "calcite saturation state"]}
{"id": "paleo.008889", "title": "Albicetus oxymycterus, a New Generic Name and Redescription of a Basal Physeteroid (Mammalia, Cetacea) from the Miocene of California, and the Evolution of Body Size in Sperm Whales", "abstract": "Living sperm whales are represented by only three species (Physeter macrocephalus, Kogia breviceps and Kogia sima), but their fossil record provides evidence of an ecologically diverse array of different forms, including morphologies and body sizes without analog among living physeteroids. Here we provide a redescription of Ontocetus oxymycterus, a large but incomplete fossil sperm whale specimen from the middle Miocene Monterey Formation of California, described by Remington Kellogg in 1925. The type specimen consists of a partial rostrum, both mandibles, an isolated upper rostrum fragment, and incomplete tooth fragments. Although incomplete, these remains exhibit characteristics that, when combined, set it apart morphologically from all other known physeteroids (e.g., a closed mesorostral groove, and the retention of enameled tooth crowns). Kellogg originally placed this species in the genus Ontocetus, a enigmatic tooth taxon reported from the 19th century, based on similarities between the type specimen Ontocetus emmonsi and the conspicuously large lower dentition of Ontocetus oxymycterus. However, the type of the genus Ontocetus is now known to represent a walrus tusk (belonging to fossil Odobenidae) instead of a cetacean tooth. Thus, we assign this species to the new genus Albicetus, creating the new combination of Albicetus oxymycterus, gen. nov. We provide new morphological observations of the type specimen, including a 3D model. We also calculate a total length of approximately 6 m in life, using cranial proxies of body size for physeteroids. Lastly, a phylogenetic analysis of Albicetus oxymycterus with other fossil and living Physeteroidea resolves its position as a stem physeteroid, implying that large body size and robust dentition in physeteroids evolved multiple times and in distantly related lineages.", "keyphrases": ["body size", "sperm whale", "albicetus oxymycterus"]}
{"id": "paleo.008491", "title": "How is biodiversity produced? Examining speciation processes during the GOBE", "abstract": "The accumulation of diversity is dependent on the production (and subsequent continuation) of new species; thus, it is important to contextualize the Great Biodiversification Event (GOBE) as the sum of a series of individual speciation events. Studies of speciation processes are only beginning to emerge for the GOBE, but early analyses of brachiopods and other taxa suggest that such research questions are tractable given appropriate data sets and analyses. In order to understand the GOBE, it is important to move from correlating diversity trends with environmental changes to explicitly assessing how correlative Earth system processes can facilitate the process and mechanisms of speciation. Explicit consideration of the hierarchical structure and biogeographical aspects of evolutionary processes provides a dynamic perspective to analyse speciation. Biogeographical processes of dispersal and vicariance provide the link\u00a0between local and global diversity levels, and oscillations between these two biogeographical modalities can generate an effective speciation dynamo. Geographical isolation due to palaeogeography, numerous interoceanic islands, tectonism, glacial\u2013interglacial cycles and newly developed habitat heterogeneity were likely key factors in promoting speciation. Understanding the processes that produced the GOBE will require careful consideration of the oceanic, climatic and tectonic processes operating during the Early Palaeozoic as well as the speciation process itself.", "keyphrases": ["speciation process", "gobe", "dispersal", "vicariance", "tectonic process"]}
{"id": "10.1073/pnas.49.3.298", "title": "A DISCUSSION AND PROPOSALS CONCERNING FOSSIL DINOFLAGELLATES, HYSTRICHOSPHERES, AND ACRITARCHS, I.", "abstract": "In 19611 I suggested that many post-Paleozoic organic microfossils that had been called hystrichospheres are really dinoflagellate cysts. Further extensive studies fully support that view. Although new findings and some revisions in details of the interpretations offered in 1961 await future publication, I feel it is appropriate now to propose several nomenclatural changes and taxonomic revisions affecting these fossils. That is the purpose of this paper, which includes (following certain background information): (1) an emendation of the dinoflagellate family Hystrichosphaeraceae, (2) proposal of three new dinoflagellate taxa: Hystrichosphaeridiaceae n., fam., Areoligeraceae n. fam., and Achomosphaera n. gen., (3) a recommendation that the term Hystrichosphaerida no longer be used and that its informal variations, such as hystrichosphere, be used cautiously, and (4) a proposal for a new informal group of microfossils of organic composition and unknown affinity to be known as acritarchs. Note on Use of Botanical Code.-Downie et al.2 recently proposed that fossil dinoflagellates and hystrichospheres (including acritarchs in the sense of this paper) be treated nomenclaturally under the Botanical Code. I have adopted this proposal (but without certain of their accessory suggestions regarding the erection of natural genera and form-genera) chiefly on the grounds (1) that, as algae, the dinoflagellates are nomenclaturally botanical entities, and (2) that the acritarchs, whose affinities are unknown (though they, too, probably, include many fossil algae), should be treated under the same code as the dinoflagellates for purely practical reasons. However, this paper is not the place to discuss some of the knotty problems raised by transferring genera and families from the realm of the Zoological Code to that of the Botanical Code; for example, problems that devolve from the distinction between natural genera, organ-genera, and form-genera under the Botanical Code and the effect of this distinction on family names proposed originally under the Zoological Oode. These and other problems are currently under extensive discussion in correspondence among interested co-workers. Slowly, workable solutions to them will emerge. For the present, I have simply used botanical family names in the same manner as zoological family names have been used in the past. Thus, Hystrichosphaeridae becomes Hystrichosphaeraceae, etc. This may not be the ideal procedure, but it seems at least a temporarily acceptable one that is consistent with stability in nomenclature, which is the spirit and purpose of nomenclatural codes. Theca, Cyst and Test.-Currently incomplete research suggests that the fossilized remains of dinoflagellates possibly nowhere include the theca, if that term is used to designate only the external cellulose or cellulose-like covering of a motile dinoflagellate cell. Instead, the fossils seem to represent a layer of considerably more resistant material that formed inside the theca. Probably the structure formed by this resistant layer was functionally a cyst, but it will be referred to herein by the", "keyphrases": ["discussion", "fossil dinoflagellate", "acritarchs"]}
{"id": "10.3176/earth.2009.4.07", "title": "Calcareous tubeworms of the Phanerozoic", "abstract": "Morphological similarities indicate that Palaeozoic problematic tubeworms, e.g. tentaculitids, cornulitids, microconchids, trypanoporids, Anticalyptraea, and Tymbochoos, form a monophyletic group. This group may also include hederelloids. Members of this group share affinities with lophophorates and their evolution could have partly been driven by predation. The extinction of Palaeozoic tubeworms in the Middle Jurassic was possibly at least partly caused by the ecological pressure by serpulid and sabellid polychaetes. The input of Palaeozoic tubeworms to the general ocean biocalcification system may have been smaller in the Ordovician to Jurassic than that of calcareous polychaetes in the Late Triassic to Recent. There seems to have been some correlation between the aragonite-calcite seas and the skeletal mineralogy of Triassic-Recent polychaete tubeworms.", "keyphrases": ["tubeworm", "phanerozoic", "tentaculitid", "trypanoporid", "common fossil"]}
{"id": "10.1017/S0016756819000670", "title": "An introduction to the Rhynie chert", "abstract": "Abstract The terrestrialization of life has profoundly affected the biosphere, geosphere and atmosphere, and the Geological Magazine has published key works charting the development of our understanding of this process. Integral to this understanding \u2013 and featuring in one of the Geological Magazine publications \u2013 is the Devonian Rhynie chert Konservat-Lagerst\u00e4tte located in Aberdeenshire, Scotland. Here we provide a review of the work on this important early terrestrial deposit to date. We begin by highlighting contributions of note in the Geological Magazine improving understanding of terrestrialization and Palaeozoic terrestrial ecosystems. We then introduce the Rhynie chert. The review highlights its geological setting: the Caledonian context of the Rhynie Basin and its nature at the time of deposition of the cherts which host its famous fossils. There follows an introduction to the development of the half-graben in which the cherts and host sediments were deposited, the palaeoenvironment this represented and the taphonomy of the fossils themselves. We subsequently provide an overview of the mineralization and geochemistry of the deposit, and then the fossils found within the Rhynie chert. These include: six plant genera, which continue to provide significant insights into the evolution of life on land; a range of different fungi, with recent work starting to probe plant\u2013fungus interactions; lichens, amoebae and a range of unicellular eukaryotes and prokaryotes (algae and cyanobacteria); and finally a range of both aquatic and terrestrial arthropods. Through continued study coupled with methodological advances, Rhynie fossils will continue to provide unique insights into early life on land.", "keyphrases": ["introduction", "rhynie chert", "fungus"]}
{"id": "10.1098/rspb.2016.1881", "title": "Slow and steady: the evolution of cranial disparity in fossil and recent turtles", "abstract": "Turtles (Testudinata) are a diverse group of amniotes that have a rich fossil record that extends back to the Late Triassic, but little is known about global patterns of disparity through time. We here investigate the cranial disparity of 172 representatives of the turtle lineage and their ancestors grouped into 20 time bins ranging from the Late Triassic until the Recent using two-dimensional geometric morphometrics. Three evolutionary phases are apparent in all three anatomical views investigated. In the first phase, disparity increases gradually from the Late Triassic to the Palaeogene with only a minor perturbation at the K/T extinct event. Although global warming may have influenced this increase, we find the Mesozoic fragmentation of Pangaea to be a more plausible factor. Following its maximum, disparity decreases strongly towards the Miocene, only to recover partially towards the Recent. The marked collapse in disparity is likely a result of habitat destruction caused by global drying, combined with the homogenization of global turtle faunas that resulted from increased transcontinental dispersal in the Tertiary. The disparity minimum in the Miocene is likely an artefact of poor sampling.", "keyphrases": ["cranial disparity", "recent", "turtle"]}
{"id": "10.3389/fmars.2017.00067", "title": "Decoupling Tooth Loss from the Evolution of Baleen in Whales", "abstract": "Baleen whales, or mysticetes, include the largest vertebrates to have ever evolved. Their gigantism, evolutionary success, and ecological diversity have been linked to filter feeding. Mysticetes filter feed using elaborate keratinous baleen plates, which grow from the palate and allow them to strain large quantities of prey out of the water. While the earliest mysticetes retained the adult, mineralized teeth present in ancestral whales, all species of living baleen whales lack teeth and instead possess baleen. The mechanism by which this evolutionary transformation took place remains unknown. We present four independent, but non-exclusive hypotheses for the origin of baleen. We evaluate the support for these hypotheses based on separate lines of evidence, including paleontological, molecular, and ontogenetic data. We suggest that the origin of baleen is decoupled from the loss of teeth, with a separate morphological and genetic basis. Moreover, we outline how new fossils and phylogenetic analyses may resolve current debates about morphological transitions in tooth loss and baleen origin across the phylogeny of stem and crown Mysticeti. Additional insights will likely arise from more detailed examination of developmental and biomechanical data, with sufficient ontogenetic and phylogenetic sampling.", "keyphrases": ["tooth loss", "baleen", "whale"]}
{"id": "10.1029/2005pa001153", "title": "Slow dynamics of the Northern Hemisphere glaciation", "abstract": "[1]\u00a0Unraveling the dynamics of the Northern Hemisphere glaciation (NHG) in the Pliocene is a key step toward a quantitative theory of the climate transition from a greenhouse to an icehouse world. Extracting the ice volume signal from marine oxygen isotope (\u03b418O) records corrupted with \u201ctemperature noise\u201d can be accomplished using statistical time series analysis. We use 45 \u03b418O records from benthic and planktonic foraminifera and globally distributed sites to reconstruct the dynamics of NHG initiation. We compare \u03b418O amplitudes with those of temperature proxy records and estimate a global ice volume\u2013related increase of 0.4\u2030, equivalent to an overall sea level lowering of 43 m. We find the NHG started significantly earlier than previously assumed, as early as 3.6 Ma, and ended at 2.4 Ma. This long-term increase points to slow, tectonic forcing such as closing of ocean gateways or mountain building as the root cause of the NHG.", "keyphrases": ["dynamic", "northern hemisphere glaciation", "pliocene"]}
{"id": "10.1080/02724634.2017.1349776", "title": "A Large Neosuchian Crocodyliform from the Upper Cretaceous (Cenomanian) Woodbine Formation of North Texas", "abstract": "ABSTRACT \n A new taxon of neosuchian crocodyliform, Deltasuchus motherali, gen. et sp. nov., is described on the basis of a partial skull recovered from the Arlington Archosaur Site within the Upper Cretaceous (Cenomanian) Woodbine Formation of north-central Texas. This productive locality represents a delta plain ecosystem preserving a diverse coastal fauna, including lungfish, turtles, dinosaurs (ornithopods and theropods), and crocodyliforms. Prior to this discovery, the only identified crocodyliforms from the Woodbine Formation had been the longirostrine taxa Terminonaris and Woodbinesuchus. This new taxon is differentiated from other known crocodyliforms by the presence of dual pseudocanines on both the dentary and maxilla; anterior and posterior rami of jugal comparable in depth; anterolaterally facing margin on the dorsal portion of the postorbital; contact between the descending process of the postorbital and the ectopterygoid; and a large, deep fossa on the ventral surface of the quadrate. Phylogenetic analysis recovers D. motherali as the sister taxon to Paluxysuchus newmani from the Lower Cretaceous Twin Mountains Formation of Texas. This clade lies within Neosuchia basal to Goniopholididae + Eusuchia. The associated cranial elements of this new crocodyliform represent a large, broad-snouted individual, an ecomorphotype often associated with the semiaquatic ambush predator niche in this clade, and one not previously reported from the formation.", "keyphrases": ["neosuchian crocodyliform", "cenomanian", "woodbine formation"]}
{"id": "10.1073/pnas.94.8.3817", "title": "Convergent evolution of antifreeze glycoproteins in Antarctic notothenioid fish and Arctic cod.", "abstract": "Antarctic notothenioid fishes and several northern cods are phylogenetically distant (in different orders and superorders), yet produce near-identical antifreeze glycoproteins (AFGPs) to survive in their respective freezing environments. AFGPs in both fishes are made as a family of discretely sized polymers composed of a simple glycotripeptide monomeric repeat. Characterizations of the AFGP genes from notothenioids and the Arctic cod show that their AFGPs are both encoded by a family of polyprotein genes, with each gene encoding multiple AFGP molecules linked in tandem by small cleavable spacers. Despite these apparent similarities, detailed analyses of the AFGP gene sequences and substructures provide strong evidence that AFGPs in these two polar fishes in fact evolved independently. First, although Antarctic notothenioid AFGP genes have been shown to originate from a pancreatic trypsinogen, Arctic cod AFGP genes share no sequence identity with the trypsinogen gene, indicating trypsinogen is not the progenitor. Second, the AFGP genes of the two fish have different intron-exon organizations and different spacer sequences and, thus, different processing of the polyprotein precursors, consistent with separate genomic origins. Third, the repetitive AFGP tripeptide (Thr-Ala/Pro-Ala) coding sequences are drastically different in the two groups of genes, suggesting that they arose from duplications of two distinct, short ancestral sequences with a different permutation of three codons for the same tripeptide. The molecular evidence for separate ancestry is supported by morphological, paleontological, and paleoclimatic evidence, which collectively indicate that these two polar fishes evolved their respective AFGPs separately and thus arrived at the same AFGPs through convergent evolution.", "keyphrases": ["antifreeze glycoprotein", "notothenioid fish", "convergent evolution"]}
{"id": "10.1073/pnas.0610947104", "title": "Environmental change preceded Caribbean extinction by 2 million years", "abstract": "Paleontologists typically treat major episodes of extinction as single and distinct events in which a major environmental perturbation results in a synchronous evolutionary response. Alternatively, the causes of biotic change may be multifaceted and extinction may lag behind the changes ultimately responsible because of nonlinear ecological dynamics. We examined these alternatives for the major episode of Caribbean extinction 2 million years ago (Ma). Isolation of the Caribbean from the Eastern Pacific by uplift of the Panamanian Isthmus was associated with synchronous changes in Caribbean near shore environments and community composition between 4.25 and 3.45 Ma. Seasonal fluctuations in Caribbean seawater temperature decreased 3-fold, carbonate deposition increased, and there was a striking, albeit patchy, shift in dominance of benthic ecosystems from heterotrophic mollusks to mixotrophic reef corals and calcareous algae. All of these changes correspond well with a simple model of decreased upwelling and collapse in planktonic productivity associated with the final stages of the closure of the isthmian barrier. However, extinction rates of mollusks and corals did not increase until 3\u20132 Ma and sharply peaked between 2 and 1 Ma, even though extinction overwhelmingly affected taxa commonly associated with high productivity. This time lag suggests that something other than environmental change per se was involved in extinction that does not occur as a single event. Understanding cause and effect will require more taxonomically refined analysis of the changing abundance and distribution patterns of different ecological guilds in the 2 million years leading up to the relatively sudden peak in extinction.", "keyphrases": ["caribbean extinction", "isolation", "environmental change"]}
{"id": "10.1111/jzs.12074", "title": "Reappraisal of early Miocene rails (Aves, Rallidae) from central France: diversity and character evolution", "abstract": "In Europe, Miocene rails (Aves, Rallidae) are quite abundant, but their phylogenetic placement in the context of recent forms has remained elusive. Rails from the early Miocene of the Saint-Gerand-le-Puy area in central France were first described in the 19th century, and currently, only two species are recognized, namely Palaeoaramides christyi and Paraortygometra porzanoides. Our examination of the material however suggests the presence of four, likely coeval, species of rail from these deposits. Palaeoaramides eximius, previously synonymized with Palaeoaramides christyi, is here shown to probably be a distinct species, and a previously unrecognized rail, Baselrallus intermedius gen. et sp. nov., is described. To find out how these fossil rails are related to modern Rallidae, we compared them with an extensive sample of extant rails and identified plesiomorphic and derived features for crown group Rallidae. Our assessment does not support a particularly close relationship of either Palaeoaramides to Aramides or Paraortygometra to Crex (Ortygometra), and overall, these fossil rails are more primitive than previously assumed. Based on our observations of the morphology of the previously undescribed humerus of Palaeoaramides, we show this taxon to be outside crown group Rallidae, and perhaps closely related to the early Oligocene taxon Belgirallus. On the other hand, Paraortygometra porzanoides bears a resemblance to recent flufftails (Sarothrura spp.) in some elements, but whether it can be included in a clade together with flufftails is uncertain.", "keyphrases": ["miocene rail", "rallidae", "central france"]}
{"id": "paleo.003406", "title": "New findings reveal that the middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin.", "abstract": "Two excellently preserved specimens of Mixosaurus cornalianus from the Anisian layers of the Middle Triassic Formazione di Besano, with soft parts associated with well-articulated skeletal elements, revealed the presence in this species of a dorsal fin and of a well-developed, triangular dorsal lobe of the caudal fin, both stiffened by an array of fibre bundles, as in Jurassic fast-swimming ichthyosaurs. This finding testifies that efficient swimming exaptations were already present in some Middle Triassic ichthyosaurs. Mixosaurus is then the oldest amniote so far known that developed a dorsal fin. The preservation of the fin shapes, scaleless skin, and three-dimensional dermal fibres is remarkable, allowing observation of their microstructure, and ruling out any artefactual interpretation. Stomach contents indicate that both specimens preyed upon cephalopods and small fishes. An internal organ, possibly a tract of the intestine, is also preserved in one specimen, which represents the first documented case in the ichthyosaurs of the Besano Formation, and a rarity in the fossil record of the clade.", "keyphrases": ["ichthyosaur", "mixosaurus", "amniote", "dorsal fin"]}
{"id": "paleo.006951", "title": "Untangling the environmental from the dietary: dust does not matter", "abstract": "Both dust and silica phytoliths have been shown to contribute to reducing tooth volume during chewing. However, the way and the extent to which they individually contribute to tooth wear in natural conditions is unknown. There is still debate as to whether dental microwear represents a dietary or an environmental signal, with far-reaching implications on evolutionary mechanisms that promote dental phenotypes, such as molar hypsodonty in ruminants, molar lengthening in suids or enamel thickening in human ancestors. By combining controlled-food trials simulating natural conditions and dental microwear textural analysis on sheep, we show that the presence of dust on food items does not overwhelm the dietary signal. Our dataset explores variations in dental microwear textures between ewes fed on dust-free and dust-laden grass or browse fodders. Browsing diets with a dust supplement simulating Harmattan windswept environments contain more silica than dust-free grazing diets. Yet browsers given a dust supplement differ from dust-free grazers. Regardless of the presence or the absence of dust, sheep with different diets yield significantly different dental microwear textures. Dust appears a less significant determinant of dental microwear signatures than the intrinsic properties of ingested foods, implying that diet plays a critical role in driving the natural selection of dental innovations.", "keyphrases": ["dust", "tooth wear", "microwear", "food", "property"]}
{"id": "10.3897/zookeys.422.6750", "title": "First fossil record of Discocephalinae (Insecta, Pentatomidae): a new genus from the middle Eocene of R\u00edo Pichileuf\u00fa, Patagonia, Argentina", "abstract": "Abstract A new genus and species of Discocephalini, Acanthocephalonotum martinsnetoi gen. n. et sp. n. is described from R\u00edo Pichileuf\u00fa, middle Eocene of Patagonia, Argentina at palaeolatitude ~ 46\u00b0S. The new species is the first fossil representative of the Discocephalinae. This taxon is extant in equatorial to subtropical America, and some species reach warm temperate latitudes (Buenos Aires province). The new genus is distinguished from the other genera of Discocephalini by the combination of these characters: interocular width greater than head length; head massive and quadrangular with the anterior margin almost straight; juga touching each other; labrum thick and curved; triangular ante-ocular process extending beyond the eye; broad spine-like antero-lateral process of the pronotum; pronotum explanate and bean shaped; scutellum triangular with a circular tongue reaching the anterior side of abdominal segment 7; and wings well developed with membrane just surpassing end of abdomen.", "keyphrases": ["discocephalinae", "new genus", "patagonia"]}
{"id": "paleo.012921", "title": "A symmoriiform from the Late Devonian of Morocco demonstrates a derived jaw function in ancient chondrichthyans", "abstract": "The Palaeozoic record of chondrichthyans (sharks, rays, chimaeras, extinct relatives) and thus our knowledge of their anatomy and functional morphology is poor because of their predominantly cartilaginous skeletons. Here, we report a previously undescribed symmoriiform shark, Ferromirum oukherbouchi, from the Late Devonian of the Anti-Atlas. Computed tomography scanning reveals the undeformed shape of the jaws and hyoid arch, which are of a kind often used to represent primitive conditions for jawed vertebrates. Of critical importance, these closely fitting cartilages preclude the repeatedly hypothesized presence of a complete gill between mandibular and hyoid arches. We show that the jaw articulation is specialized and drives mandibular rotation outward when the mouth opens, and inward upon closure. The resultant eversion and inversion of the lower dentition presents a greater number of teeth to prey through the bite-cycle. This suggests an increased functional and ecomorphological disparity among chondrichthyans preceding and surviving the end-Devonian extinctions.", "keyphrases": ["late devonian", "chondrichthyan", "shark", "jawed vertebrate"]}
{"id": "10.5194/gmd-11-1033-2018", "title": "The PMIP4 contribution to CMIP6 \u2013 Part 1: Overview and over-arching analysis plan", "abstract": "Abstract. This paper is the first of a series of four GMD papers on the PMIP4-CMIP6 experiments. Part\u00a02 (Otto-Bliesner et al., 2017) gives details about the two PMIP4-CMIP6 interglacial experiments, Part\u00a03 (Jungclaus et al., 2017) about the last millennium experiment, and Part\u00a04 (Kageyama et al., 2017) about the Last Glacial Maximum experiment. The mid-Pliocene Warm Period experiment is part of the Pliocene Model Intercomparison Project (PlioMIP) \u2013 Phase 2, detailed in Haywood et al.\u00a0(2016). The goal of the Paleoclimate Modelling Intercomparison Project (PMIP) is to understand the response of the climate system to different climate forcings for documented climatic states very different from the present and historical climates. Through comparison with observations of the environmental impact of these climate changes, or with climate reconstructions based on physical, chemical, or biological records, PMIP also addresses the issue of how well state-of-the-art numerical models simulate climate change. Climate models are usually developed using the present and historical climates as references, but climate projections show that future climates will lie well outside these conditions. Palaeoclimates very different from these reference states therefore provide stringent tests for state-of-the-art models and a way to assess whether their sensitivity to forcings is compatible with palaeoclimatic evidence. Simulations of five different periods have been designed to address the objectives of the sixth phase of the Coupled Model Intercomparison Project (CMIP6): the millennium prior to the industrial epoch (CMIP6 name: past1000); the mid-Holocene, 6000\u00a0years ago (midHolocene); the Last Glacial Maximum, 21\u202f000\u00a0years ago (lgm); the Last Interglacial, 127\u202f000\u00a0years ago (lig127k); and the mid-Pliocene Warm Period, 3.2 million years ago (midPliocene-eoi400).\u00a0These climatic periods are well documented by palaeoclimatic and palaeoenvironmental records, with climate and environmental changes relevant for the study and projection of future climate changes. This paper describes the motivation for the choice of these periods and the design of the numerical experiments and database requests, with a focus on their novel features compared to the experiments performed in previous phases of PMIP and CMIP. It also outlines the analysis plan that takes advantage of the comparisons of the results across periods and across CMIP6 in collaboration with other MIPs.", "keyphrases": ["cmip6", "analysis plan", "last glacial maximum"]}
{"id": "paleo.000259", "title": "New opabiniid diversifies the weirdest wonders of the euarthropod stem group", "abstract": "Once considered \u2018weird wonders\u2019 of the Cambrian, the emblematic Burgess Shale animals Anomalocaris and Opabinia are now recognized as lower stem-group euarthropods and have provided crucial data for constraining the polarity of key morphological characters in the group. Anomalocaris and its relatives (radiodonts) had worldwide distribution and survived until at least the Devonian. However, despite intense study, Opabinia remains the only formally described opabiniid to date. Here we reinterpret a fossil from the Wheeler Formation of Utah as a new opabiniid, Utaurora comosa nov. gen. et sp. By visualizing the sample of phylogenetic topologies in treespace, our results fortify support for the position of U. comosa beyond the nodal support traditionally applied. Our phylogenetic evidence expands opabiniids to multiple Cambrian stages. Our results underscore the power of treespace visualization for resolving imperfectly preserved fossils and expanding the known diversity and spatio-temporal ranges within the euarthropod lower stem group.", "keyphrases": ["opabiniid", "stem group", "weird wonder"]}
{"id": "paleo.008025", "title": "Cope's rule and the adaptive landscape of dinosaur body size evolution", "abstract": "The largest known dinosaurs weighed at least 20 million times as much as the smallest, indicating exceptional phenotypic divergence. Previous studies have focused on extreme giant sizes, tests of Cope's rule, and miniaturization on the line leading to birds. We use non\u2010uniform macroevolutionary models based on Ornstein\u2013Uhlenbeck and trend processes to unify these observations, asking: what patterns of evolutionary rates, directionality and constraint explain the diversification of dinosaur body mass? We find that dinosaur evolution is constrained by attraction to discrete body size optima that undergo rare, but abrupt, evolutionary shifts. This model explains both the rarity of multi\u2010lineage directional trends, and the occurrence of abrupt directional excursions during the origins of groups such as tiny pygostylian birds and giant sauropods. Most expansion of trait space results from rare, constraint\u2010breaking innovations in just a small number of lineages. These lineages shifted rapidly into novel regions of trait space, occasionally to small sizes, but most often to large or giant sizes. As with Cenozoic mammals, intermediate body sizes were typically attained only transiently by lineages on a trajectory from small to large size. This demonstrates that bimodality in the macroevolutionary adaptive landscape for land vertebrates has existed for more than 200 million years.", "keyphrases": ["rule", "landscape", "body size", "macroevolutionary model", "sauropod"]}
{"id": "10.1666/0094-8373-35.3.367", "title": "Foraminiferal diversification during the late Paleozoic ice age", "abstract": "Abstract A record of late Paleozoic foraminiferal diversity, origination and extinction frequencies, and provincialism at million-year temporal resolution and species-level taxonomic resolution has been achieved by analyzing composite standard databases. Foraminiferal species diversity increased throughout Mississippian and Pennsylvanian time leading up to its peak at the Pennsylvanian/Permian boundary. Foraminifers then experienced a steep decline in diversity during the Early Permian. Frequencies of origination and extinction broadly tracked changes in global diversity. From Late Mississippian time onward, patterns in total foraminiferal diversity were dominated by fusulinoideans. There is no clear relationship between rates of foraminiferal evolution and the alternating glacial and nonglacial intervals that characterized the late Paleozoic ice age. Rather, high rates of origination and extinction might reflect instability of neritic environments as a consequence of high-frequency, high-amplitude base-level fluctuations (cyclothemic deposition). Further, the advent of algal symbiosis in fusulinoideans was a physiologic innovation that promoted diversification as these symbiont-bearing taxa experimented with morphologic adaptations for partitioning the low-nutrient environments to which they were specialized. Growth to large size and delayed maturation in fusulinoideans might have been enabled by the late Paleozoic hyperoxic atmosphere and the widespread development of oligotrophic, carbonate platform and shelf environments. The late Paleozoic history of foraminiferal diversification was influenced also by closure of the Rheic Ocean beginning in Late Mississippian time. Foraminiferal associations on opposite sides of Pangea exhibited relatively high similarity prior to the closure, but then similarity decreased steadily after destruction of the subequatorial marine corridor. Arctic-Eurasian and North American associations were nearly isolated from one another throughout the main burst of fusulinoidean diversification, so that parallel lineages developed independently in the two regions, resulting in many instances of convergence.", "keyphrases": ["diversification", "paleozoic ice age", "foraminiferal diversification"]}
{"id": "paleo.007511", "title": "The decline of silky lacewings and morphological diversity of long-nosed antlion larvae through time", "abstract": "Psychopsidae (silky lacewings) is a species-poor ingroup of Neuroptera. Silky lacewings show a distinct relic distribution, indicating that the group was more species-rich and diverse in the past. Silky lacewings have distinct larvae that resemble antlion larvae but differ from these in lacking teeth on their mouth parts, and in having a projecting labrum, which makes them \u201clong-nosed antlion larvae\u201d. These larvae are well known from Myanmar amber (about 100 mya) and Baltic amber (mostly 34\u201338 mya, possibly 23\u201348 mya), as well as from the extant fauna. We report and figure numerous additional specimens from both amber types and from ca. 100 mya old French Charentese amber, expanding the known record of well-illustrated extant and fossil specimens from 26 to 52 specimens. We compare the diversity of head shape among these larvae through time by outline analysis. Results indicate that morphological diversity was pro-nouncedly higher in the Cretaceous, even after sample size correction. Eocene representatives are more diverse than modern representatives, but less diverse than Cretaceous ones, in one shape aspect that explains most of the overall variation (55.7%). Eocene representatives are less diverse in another shape aspect that explains the second-most variation (26.9%), but this might reflect a lack of first larval stage specimens. There seems to be no strong correlation between size and shape. This type of analysis enables a test for the loss of diversity over time, based on morphological diversity as a proxy, without the requirement of identifying fossil larvae down to a narrow taxonomical range.", "keyphrases": ["silky lacewing", "morphological diversity", "antlion"]}
{"id": "10.1051/bsgf/2017180", "title": "Mesozoic and Cenozoic decapod crustaceans from the Basque-Cantabrian basin (Western Pyrenees): new occurrences and faunal turnovers in the context of basin evolution", "abstract": "Twenty-nine new identifications of fossil decapod crustacean remains in the Basque-Cantabrian Basin (Western Pyrenees) spanning from the Jurassic to the Miocene and coming from twenty-four new and five yet known localities are described here for the first time. These remains represent a substantial advance in the knowledge of these faunas and their diversity in this basin, giving an accurate image of the decapod faunal succession. The study includes a taxonomical description and discussion with reference to the known occurrences. Their accurate dating and the environmental ascription have been possible after the analysis of the stratigraphic occurrence in the context of a well-known basinal stratigraphy. This has ultimately permitted a brief analysis of the decapod palaeoecology and faunal turnovers in the context of basin evolution.", "keyphrases": ["basque-cantabrian basin", "western pyrenees", "faunal turnover"]}
{"id": "10.26879/579", "title": "Fruits, seeds and flowers from the Bovay and Bolden clay pits (early Eocene Tallahatta Formation, Claiborne Group), northern Mississippi, USA", "abstract": "This report is the second of a series of comprehensive reviews of the reproductive material from localities of the Eocene Claiborne Group of the southeastern United States. We examine fossil plant reproductive material from two localities, the Bovay and Bolden clay pits, in northern Mississippi, USA. The investigation of 193 specimens has resulted in the recognition of 52 taxa/morphotypes. Based upon comparisons of gross morphology of these specimens with available extant plant material and the literature, we are able to relate 17 taxa/morphotypes to the following 11 extant families: Annonaceae (1), Araliaceae (1), Caprifoliaceae (1), Eucommiaceae (1), Fabaceae (6), Fagaceae (2), Icacinaceae (1), Sapindaceae (1), Salicaceae (1), Rhamnaceae (1), and Theaceae (1). In addition, 35 morphotypes are not assigned to any family due to the limited number of diagnostic characters. Of the 52 taxa/morphotypes recognized, 38 (73.1%) are unique to the Bovay locality and nine (17.3%) are unique to Bolden. Only five (9.6%) taxa/morphotypes are shared by the two localities. Of the 62 taxa/morphotypes recognized from the Warman clay pit, Tennessee, only eight taxa/morphotypes are shared with the Bovay and/or Bolden localities, Mississippi. This study has expanded our knowledge of the Eocene plant diversity of the southeastern United States and has shown that there is a remarkable lack of species overlap among the three localities examined to date. Jane Blanchard. Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA Ojjhblanchard@aol.com Hongshan Wang. Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA hwang@flmnh.ufl.edu (corresponding author) David L. Dilcher. Departments of Biology and Geology, Indiana University, Bloomington, Indiana 47405, USA dilcher@indiana.edu", "keyphrases": ["bovay", "bolden clay pit", "northern mississippi", "reproductive material", "morphotype"]}
{"id": "paleo.006889", "title": "Analysis of septal spacing and septal crowding in Devonian and Carboniferous ammonoids", "abstract": "Septal crowding is widely known as a sign of maturity in conchs of ammonoids and nautiloids. However, reduced septal spacing may also occur as a consequence of adverse ecological conditions. Here, we address the question how septal spacing varied through ontogeny in representatives of some of the major clades of Devonian and Carboniferous ammonoids. We found that the degree of ontogenetic variation is similar between clades and that variation is only weakly linked with conch form. The results show that septal crowding alone is insufficient to identify adulthood in ammonoids; intermediate septal crowding is a common phenomenon and occurs in various growth stages. Changes in septal distances during ontogeny were, in addition to adulthood of the individuals, a passive reaction likely caused by fluctuating environmental conditions.", "keyphrases": ["septal spacing", "carboniferous ammonoid", "ammonoid", "distance", "rotational angle"]}
{"id": "10.1080/14772019.2013.847870", "title": "Cretaceous soft-shelled turtles (Trionychidae) of Mongolia: new diversity, records and a revision", "abstract": "This paper is devoted to the description and revision of material of Cretaceous soft-shelled turtles (Trionychidae) of Mongolia. It includes the description of seven trionychid species, six of which are new, and two new genera: the cyclanorbine Nemegtemys conflata gen. et sp. nov. from the Nemegt Formation (Maastrichtian), and the trionychines Gobiapalone breviplastra gen. et sp. nov. from the Nemegt and Barungoyot (Campanian) formations, G. orlovi from the Baynshire Formation (Cenomanian\u2013Santonian), \u2018Trionyx\u2019 baynshirensis sp. nov. from the Baynshire Formation, \u2018T.\u2019 gilbentuensis sp. nov. from the Nemegt Formation, \u2018T.\u2019 gobiensis sp. nov. from the Nemegt Formation, and \u2018T.\u2019 shiluutulensis sp. nov. from an unknown formation (Campanian). In addition, one shell from the ?Baynshire Formation of Khermin Tsav is assigned to Gobiapalone sp. The type material of Amyda menneri is considered to be Trionychidae indet. and Amyda menneri to be a nomen dubium. Finally, we revise other available materials of Cretaceous trionychids from 45 localities in Mongolia. Nemegtemys conflata, if correctly assigned, is the earliest known member of Cyclanorbinae. The two species of the new genus Gobiapalone are included in two phylogenetic analyses of Trionychidae. In both analyses Gobiapalone is monophyletic. In the first analysis, Gobiapalone is placed within Apalonina. In the second analysis, Gobiapalone is sister to Apalonina. Thus, the results of both analyses show that Apalonina, which is a rather advanced and well-supported trionychid clade, or its closest sister taxon (stem-Apalonina), were present in the Late Cretaceous of Asia. These results suggest that most other supra-generic clades of modern trionychids had been established in Asia by the Late Cretaceous. That suggestion is supported by the discovery of a cyclanorbine Nemegtemys conflata in the Late Cretaceous of Mongolia. Finally we summarize the latest data on temporal and geographical distributions of Cretaceous Trionychidae of Asia and North America. http://zoobank.org/urn:lsid:zoobank.org:pub:921DA1C5-C4B2-463D-A49D-608024C6036A", "keyphrases": ["trionychidae", "mongolia", "cretaceous soft-shelled turtle"]}
{"id": "10.1073/pnas.1402369111", "title": "Age constraints on the dispersal of dinosaurs in the Late Triassic from magnetochronology of the Los Colorados Formation (Argentina)", "abstract": "Significance Uncertainties in reported 40Ar/39Ar dates from the Ischigualasto Formation of Argentina allow its dinosaur-bearing fauna to be Norian in age and possibly contemporaneous with some of the older U-Pb dated dinosaur-bearing units in the Chinle Formation of the American Southwest. Our magnetochronology of the previously undated Los Colorados Formation, which also contains a diverse dinosaur assemblage, constrains its age to the interval from 227 to 213 Ma (Norian) and thereby largely restricts the underlying Ischigualasto Formation to the Carnian. Rise of early dinosaurs was thus diachronous across the Americas with their dispersal from the austral temperate belt blocked until later in the Norian. The breakout may have resulted from critically lowered climatic barriers associated with decreasing atmospheric pCO2 levels. A measured magnetozone sequence defined by 24 sampling sites with normal polarity and 28 sites with reverse polarity characteristic magnetizations was established for the heretofore poorly age-constrained Los Colorados Formation and its dinosaur-bearing vertebrate fauna in the Ischigualasto\u2013Villa Union continental rift basin of Argentina. The polarity pattern in this \u223c600-m-thick red-bed section can be correlated to Chrons E7r to E15n of the Newark astrochronological polarity time scale. This represents a time interval from 227 to 213 Ma, indicating that the Los Colorados Formation is predominantly Norian in age, ending more than 11 My before the onset of the Jurassic. The magnetochronology confirms that the underlying Ischigualasto Formation and its vertebrate assemblages including some of the earliest known dinosaurs are of Carnian age. The oldest dated occurrences of vertebrate assemblages with dinosaurs in North America (Chinle Formation) are younger (Norian), and thus the rise of dinosaurs was diachronous across the Americas. Paleogeography of the Ischigualasto and Los Colorados Formations indicates prolonged residence in the austral temperate humid belt where a provincial vertebrate fauna with early dinosaurs may have incubated. Faunal dispersal across the Pangean supercontinent in the development of more cosmopolitan vertebrate assemblages later in the Norian may have been in response to reduced contrasts between climate zones and lowered barriers resulting from decreasing atmospheric pCO2 levels.", "keyphrases": ["late triassic", "magnetochronology", "los colorados formation"]}
{"id": "10.1590/S0074-02762003000900026", "title": "Louse infestation of the Chiribaya culture, southern Peru: variation in prevalence by age and sex.", "abstract": "In order to improve the interpretive potential of archaeoparasitology, it is important to demonstrate that the epidemiology of ancient parasites is comparable to that of modern parasites. Once this is demonstrated, then we can be secure that the evidence of ancient parasitism truly reflects the pathoecology of parasitic disease. Presented here is an analysis of the paleoepidemiology of Pediculus humanus infestation from 146 mummies from the Chiribaya culture 1000-1250 AD of Southern Peru. The study demonstrates the modern parasitological axiom that 10% of the population harbors 70% of the parasites holds true for ancient louse infestation. This is the first demonstration of the paleoepidemiology of prehistoric lice infestation.", "keyphrases": ["chiribaya culture", "southern peru", "louse infestation"]}
{"id": "paleo.011869", "title": "The Horseshoe Crab of the Genus Limulus: Living Fossil or Stabilomorph?", "abstract": "A new horseshoe crab species, Limulus darwini, is described from the uppermost Jurassic (ca. 148 Ma) near-shore sediments of the Kcynia Formation, central Poland. The only extant species Limulus polyphemus (Linnaeus) inhabits brackish-marine, shallow water environments of the east coast of the United States. Here it is shown that there are no important morphological differences between the Kcynia Formation specimens and extant juvenile representatives of the genus Limulus. The palaeoecological setting inhabited by the new species and the trophic relationships of extant horseshoe crabs are discussed in an attempt to determine the potential range of food items ingested by these Mesozoic xiphosurans. In this paper we propose the adoption of a new term stabilomorphism, this being: an effect of a specific formula of adaptative strategy among organisms whose taxonomic status does not exceed genus-level. A high effectiveness of adaptation significantly reduces the need for differentiated phenotypic variants in response to environmental changes and provides for long-term evolutionary success.", "keyphrases": ["horseshoe crab", "living fossil", "stabilomorph"]}
{"id": "paleo.007246", "title": "Delayed recovery of non-marine tetrapods after the end-Permian mass extinction tracks global carbon cycle", "abstract": "During the end-Permian mass extinction, marine ecosystems suffered a major drop in diversity, which was maintained throughout the Early Triassic until delayed recovery during the Middle Triassic. This depressed diversity in the Early Triassic correlates with multiple major perturbations to the global carbon cycle, interpreted as either intrinsic ecosystem or external palaeoenvironmental effects. In contrast, the terrestrial record of extinction and recovery is less clear; the effects and magnitude of the end-Permian extinction on non-marine vertebrates are particularly controversial. We use specimen-level data from southern Africa and Russia to investigate the palaeodiversity dynamics of non-marine tetrapods across the Permo-Triassic boundary by analysing sample-standardized generic richness, evenness and relative abundance. In addition, we investigate the potential effects of sampling, geological and taxonomic biases on these data. Our analyses demonstrate that non-marine tetrapods were severely affected by the end-Permian mass extinction, and that these assemblages did not begin to recover until the Middle Triassic. These data are congruent with those from land plants and marine invertebrates. Furthermore, they are consistent with the idea that unstable low-diversity post-extinction ecosystems were subject to boom\u2013bust cycles, reflected in multiple Early Triassic perturbations of the carbon cycle.", "keyphrases": ["recovery", "non-marine tetrapod", "end-permian mass extinction", "ecosystem", "middle triassic"]}
{"id": "paleo.005873", "title": "Chemical characterization of pterosaur melanin challenges color inferences in extinct animals", "abstract": "Melanosomes (melanin-bearing organelles) are common in the fossil record occurring as dense packs of globular microbodies. The organic component comprising the melanosome, melanin, is often preserved in fossils, allowing identification of the chemical nature of the constituent pigment. In present-day vertebrates, melanosome morphology correlates with their pigment content in selected melanin-containing structures, and this interdependency is employed in the color reconstruction of extinct animals. The lack of analyses integrating the morphology of fossil melanosomes with the chemical identification of pigments, however, makes these inferences tentative. Here, we chemically characterize the melanin content of the soft tissue headcrest of the pterosaur Tupandactylus imperator by alkaline hydrogen peroxide oxidation followed by high-performance liquid chromatography. Our results demonstrate the unequivocal presence of eumelanin in T. imperator headcrest. Scanning electron microscopy followed by statistical analyses, however, reveal that preserved melanosomes containing eumelanin are undistinguishable to pheomelanin-bearing organelles of extant vertebrates. Based on these new findings, straightforward color inferences based on melanosome morphology may not be valid for all fossil vertebrates, and color reconstructions based on ultrastructure alone should be regarded with caution.", "keyphrases": ["melanin", "color inference", "extinct animal", "microbodie", "electron microscopy"]}
{"id": "10.1073/pnas.0706977104", "title": "Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling", "abstract": "A carbon-rich black layer, dating to \u224812.9 ka, has been previously identified at \u224850 Clovis-age sites across North America and appears contemporaneous with the abrupt onset of Younger Dryas (YD) cooling. The in situ bones of extinct Pleistocene megafauna, along with Clovis tool assemblages, occur below this black layer but not within or above it. Causes for the extinctions, YD cooling, and termination of Clovis culture have long been controversial. In this paper, we provide evidence for an extraterrestrial (ET) impact event at \u224512.9 ka, which we hypothesize caused abrupt environmental changes that contributed to YD cooling, major ecological reorganization, broad-scale extinctions, and rapid human behavioral shifts at the end of the Clovis Period. Clovis-age sites in North American are overlain by a thin, discrete layer with varying peak abundances of (i) magnetic grains with iridium, (ii) magnetic microspherules, (iii) charcoal, (iv) soot, (v) carbon spherules, (vi) glass-like carbon containing nanodiamonds, and (vii) fullerenes with ET helium, all of which are evidence for an ET impact and associated biomass burning at \u224812.9 ka. This layer also extends throughout at least 15 Carolina Bays, which are unique, elliptical depressions, oriented to the northwest across the Atlantic Coastal Plain. We propose that one or more large, low-density ET objects exploded over northern North America, partially destabilizing the Laurentide Ice Sheet and triggering YD cooling. The shock wave, thermal pulse, and event-related environmental effects (e.g., extensive biomass burning and food limitations) contributed to end-Pleistocene megafaunal extinctions and adaptive shifts among PaleoAmericans in North America.", "keyphrases": ["extraterrestrial impact", "megafaunal extinction", "younger dryas"]}
{"id": "paleo.002239", "title": "A New Madtsoiid Snake from the Paleogene of South America (Northwestern Argentina), Based on an Articulated Postcranial Skeleton", "abstract": "ABSTRACT The Madtsoiidae are an extinct lineage of snakes known from the Late Cretaceous to the Late Pleistocene, with a rich fossil record distributed mainly across Gondwanan landmasses. However, only a few taxa are represented by cranial or articulated remains, and most madtsoiids are known only by isolated vertebrae. The unambiguous record of Madtsoiidae from the Cenozoic in South America had been restricted to the genus Madtsoia from Eocene and Oligocene deposits of Patagonia and Brazil. Here, we describe a new madtsoiid taxon, Powellophis andina gen. et sp. nov., based on an articulated postcranial skeleton from the Mealla Formation (middle\u2013late Paleocene) in northwestern Argentina. The new taxon is estimated to be around 3 meters long, with a vertebral morphology sharing similar features with other mid-to-large forms. Its inclusion in a recent analysis of madtsoiid relationships recovers Powellophis as an early member of a clade formed by mostly large bodied and gigantic taxa. Its presence in the Paleocene of northwestern Argentina fills the gap between the diverse Late Cretaceous and Eocene\u2013Oligocene records of madtsoiids in South America, confirms their presence in northern Gondwana by the early Paleogene, and expands the diversity of the group.", "keyphrases": ["new madtsoiid snake", "paleogene", "northwestern argentina", "postcranial skeleton"]}
{"id": "paleo.004339", "title": "Environmental preferences of brachiopods and bivalves across major climatic changes during the Late Palaeozoic ice age (Pennsylvanian, western Argentina)", "abstract": "During the late Palaeozoic ice age (LPIA), ice\u2010proximal marine regional communities record contrasting responses to climate change compared to ice\u2010distal communities. However, there is still much to be understood in distal regions in order to fully understand the palaeobiological consequences of the LPIA. Here, were analyse brachiopod and bivalve environmental preferences along the bathymetric gradient during a major glacial event and the subsequent non\u2010glacial interval in western Argentina. Median environmental breadths did not change with the reassembly of communities during the non\u2010glacial interval. Moreover, bivalves and brachiopod immigrants show similar environmental breadths although they tend to have immigrated from different palaeogeographical regions. These patterns reinforce the idea that the worldwide marine fauna was probably culled of stenotopic taxa during the LPIA. On the other hand, analysis of the preferred depths of survivors and immigrants sheds light on the substantial modification of the bathymetric diversity gradient. Among different possible explanations, the immigration of taxa with affinities for deep environments is the only one supported. In addition, results underscore the observation that the higher turnover in the offshore environment was probably driven by immigration rather than extinction. Finally, stability in environmental preferences at a regional scale is not mirrored by stability in survivors\u2019 individual preferences, because survivors\u2019 preferred depth is not correlated during the glacial and non\u2010glacial intervals. Moreover, the amount of change in survivors preferred depth is not related to their environmental breadth, nor to their occupancy. These patterns suggest: (1) instability in realized niches; and (2) individual responses of survivor genera.", "keyphrases": ["bivalve", "climate change", "western argentina", "environmental preference"]}
{"id": "paleo.002724", "title": "Fossil-Lagerst\u00e4tte Enspel\u2013a short review of current knowledge, the fossil association, and a bibliography", "abstract": "Almost two decades ago, the Generaldirektion Kulturelles Erbe Rheinland-Pfalz initiated annual field campaigns in order to investigate geological and palaeobiological aspects of the Fossil-Lagerst\u00e4tte Enspel, an upper Oligocene crater lake. Since then, the fossil-bearing 'oilshale' became more and more exposed due to the removal of the overlying basalt, which is still being commercially exploited. This contribution briefly summarizes the current knowledge that accumulated mainly within the last 20 years, gives a taxonomic listing of the fossil association, and includes a bibliography.", "keyphrases": ["current knowledge", "fossil association", "bibliography", "oligocene", "excavation"]}
{"id": "10.1029/2009GL039309", "title": "Tidal mixing and the Meridional Overturning Circulation from the Last Glacial Maximum", "abstract": "Using a global tidal model it is shown that the supply of tidal energy to the deep ocean was larger during the Last Glacial Maximum (LGM; 18,000\u201322,000 years BP). The results were used to modify the rate of vertical mixing in a coupled ocean\u2010atmosphere model set up for the present and LGM oceans. The increased levels of mechanical energy during the LGM were countered by a fresher upper North Atlantic, which led to a reduced circulation and deep water formation in spite of a trebling of the implicit mixing energy. This identifies the significance of accurately representing vertical mixing in climate models to estimate the recovery time\u2010scales and timings of rapid catastrophic paleoceanographic events. From the estimated levels of implicit energy in the vertical mixing scheme an amendment to diffusivity based mixing schemes is suggested.", "keyphrases": ["mixing", "glacial maximum", "tidal mixing"]}
{"id": "10.1126/science.1184950", "title": "Geological Setting and Age of Australopithecus sediba from Southern Africa", "abstract": "From Australopithecus to Homo Our genus Homo is thought to have evolved a little more than 2 million years ago from the earlier hominid Australopithecus. But there are few fossils that provide detailed information on this transition. Berger et al. (p. 195; see the cover) now describe two partial skeletons, including most of the skull, pelvis, and ankle, of a new species of Australopithecus that are informative. The skeletons were found in a cave in South Africa encased in sediments dated by Dirks et al. (p. 205) to about 1.8 to 1.9 million years ago. The fossils share many derived features with the earliest Homo species, including in its pelvis and smaller teeth, and imply that the transition to Homo was in stages. A new species of Australopithecus, about 1.9 million years old, shows many derived features with Homo, helping to reveal its evolution. We describe the geological, geochronological, geomorphological, and faunal context of the Malapa site and the fossils of Australopithecus sediba. The hominins occur with a macrofauna assemblage that existed in Africa between 2.36 and 1.50 million years ago (Ma). The fossils are encased in water-laid, clastic sediments that were deposited along the lower parts of what is now a deeply eroded cave system, immediately above a flowstone layer with a U-Pb date of 2.026 \u00b1 0.021 Ma. The flowstone has a reversed paleomagnetic signature and the overlying hominin-bearing sediments are of normal polarity, indicating deposition during the 1.95- to 1.78-Ma Olduvai Subchron. The two hominin specimens were buried together in a single debris flow that lithified soon after deposition in a phreatic environment inaccessible to scavengers.", "keyphrases": ["australopithecus sediba", "south africa", "hominin specimen"]}
{"id": "10.1029/2000PA000530", "title": "Attenuation of millennial-scale events by bioturbation in marine sediments", "abstract": "The discovery of large, millennial-scale oscillations (1- 10 kyr period) in climate records from ice cores and marine sediments in the North Atlantic has motivated the search to understand their cause and evaluate the geographic extent of this variability. One uncertainty in comparing marine geologic records of millennial-scale variability is the extent to which mixing of sediment by organisms at the seafloor (bioturbation) may attenuate millennial-scale events in the stratigraphic record. Evidence of attenuation of millennial variability can be found in cores with sedimentation rates in the range of 5 -15 cm/kyr. Modeling the attenuation of a hypothetical input time series similar to GISP2 using a moderate level of mixing provides estimates of attenuation as a function of sedimentation rate. The amplitude of a 4 kyr duration event is reduced by 50% for sedimentation rates10 cm/kyr and reduced by 20% for sedimentation rates of 20 cm/kyr. Minimal attenuation (<5%) is achieved only when the sedimentation rate exceeds 50 cm/kyr for a 4 kyr duration event and 70 cm/kyr for a 2 kyr duration event. The intensity of mixing plays a role in determining how much attenuation occurs. The amplitude of a 4 kyr duration event in a 10 cm/kyr core is reduced by 75% under strong mixing or reduced by 25% under weak mixing. This study indicates that the original amplitude of Dansgaard-Oeschger (DO) millennial-scale events observed during the last glacial may be twice the observed amplitude for cores with sedimentation rates 10 - 20 cm/kyr that have experienced moderate bioturbation. Regional comparisons of the amplitude of millennial-scale variability will require cores with weak mixing or sedimentation rates exceeding 50 cm/kyr in order to avoid biased estimates of the amplitude of millennial-scale (4 kyr duration) variability.", "keyphrases": ["millennial-scale event", "bioturbation", "marine sediment", "amplitude"]}
{"id": "paleo.002345", "title": "Amphibia of Enspel (Late Oligocene, Germany)", "abstract": "Amphibia from the Late Oligocene (MP 28) locality Enspel, Germany are represented by two caudates: a hyperossified salamandrid Chelotriton paradoxus and an indeterminate salamandrid different from Chelotriton in proportions of vertebral column. Anurans are represented by two forms of the genus Palaeobatrachus, one of which is nearly as large as P. gigas (now synonymized with P. grandipes). Pelobates cf. decheni, represented in this locality by three nearly complete adult skeletons and a large number of tadpoles, is the earliest record for the genus. Compared with later representatives of the genus, it does not yet possess specializations for burrowing. Ranidae are represented by two rather fragmentary and incomplete skeletons referred to as Rana sp. A comparatively large series of tadpoles was assigned to the Pelobatidae on the basis of tripartite frontoparietal complex. Most of them are premetamorphic larvae, and a few older ones are postmetamorphic, but they do not exceed Gossner stage 42.\nOne specimen is a large premetamorphic tadpole (no rudimentary limbs) with a total body length of 147 mm. Anatomically, it can be equally assigned to Pelobates or to Eopelobates; the second possibility was excluded only on the basis of absence of adult Eopelobates in this locality.", "keyphrases": ["late oligocene", "germany", "amphibia"]}
{"id": "paleo.011401", "title": "Ecomorphological diversification in squamates from conserved pattern of cranial integration", "abstract": "Significance With >10,000 living species, squamate reptiles (lizards, snakes) exhibit enormous phenotypic variation reflecting their incredible range in ecology and developmental strategies. What drove this exceptional diversity? We analyze high-density surface morphometric data for skulls representing \u223c200 modern and extinct species to provide a comprehensive, clade-wide investigation of how ecological and developmental factors contributed to cranial evolution across geologic time, skull regions, and taxa. Although diet and habitat have had an overarching impact on skull evolution (e.g., herbivory, along with aquatic and fossorial habitats, are associated with rapid evolution), lizards and snakes surprisingly share a common pattern of trait correlations (integration). The remarkable ecological and morphological diversity in squamates thus arose from selection acting on a conserved architecture of phenotypic integration. Factors intrinsic and extrinsic to organisms dictate the course of morphological evolution but are seldom considered together in comparative analyses. Among vertebrates, squamates (lizards and snakes) exhibit remarkable morphological and developmental variations that parallel their incredible ecological spectrum. However, this exceptional diversity also makes systematic quantification and analysis of their morphological evolution challenging. We present a squamate-wide, high-density morphometric analysis of the skull across 181 modern and extinct species to identify the primary drivers of their cranial evolution within a unified, quantitative framework. Diet and habitat preferences, but not reproductive mode, are major influences on skull-shape evolution across squamates, with fossorial and aquatic taxa exhibiting convergent and rapid changes in skull shape. In lizards, diet is associated with the shape of the rostrum, reflecting its use in grasping prey, whereas snakes show a correlation between diet and the shape of posterior skull bones important for gape widening. Similarly, we observe the highest rates of evolution and greatest disparity in regions associated with jaw musculature in lizards, whereas those forming the jaw articulation evolve faster in snakes. In addition, high-resolution ancestral cranial reconstructions from these data support a terrestrial, nonfossorial origin for snakes. Despite their disparate evolutionary trends, lizards and snakes unexpectedly share a common pattern of trait integration, with the highest correlations in the occiput, jaw articulation, and palate. We thus demonstrate that highly diverse phenotypes, exemplified by lizards and snakes, can and do arise from differential selection acting on conserved patterns of phenotypic integration.", "keyphrases": ["squamate", "integration", "ecology", "skull"]}
{"id": "10.1666/10-059.1", "title": "A New, Early Puercan (Earliest Paleocene) Species of Purgatorius (Plesiadapiformes, Primates) from Saskatchewan, Canada", "abstract": "Abstract The early Paleocene Purgatorius Van Valen and Sloan is the most primitive plesiadapiform primate yet discovered, mostly known from middle to late Puercan strata in Montana, deposited during the interval C29N of the geomagnetic polarity time scale. Here we describe Purgatorius coracis n. sp. from the Ravenscrag Formation, at the Rav W-1 horizon, Medicine Hat Brick and Tile Quarry, southwestern Saskatchewan. This horizon occurs within C29R, making P. coracis the earliest known primate, while strengthening the evidence that plesiadapiforms, and hence primates, originated and underwent their initial evolutionary diversification in North America. Most North American mammalian local faunas correlating with C29R have been assigned to the Pu1 (earliest Puercan) interval zone, but the taxonomic composition of the mammals accompanying P. coracis at Rav W-1 more resembles local faunas of Pu2 age. The occurrence at Rav W-1 of Pu2 aspect mammals within C29R agrees with similar occurrences at the Hiatt and PITA Flats localities in Montana and North Dakota, also possibly correlated with C29R. The evidence from these three sites, all in the Williston Basin, suggests that in some areas of the Western Interior Pu2 aspect local faunas were coeval with those of latest Pu1 age, having evolved earlier than has commonly been assumed.", "keyphrases": ["puercan", "plesiadapiform", "saskatchewan"]}
{"id": "10.1139/cjes-2014-0183", "title": "A wide-gauge, large-mammal trackway from the upper Paleocene of Alberta, Canada", "abstract": "A very rare 11.2 m long wide-gauge trackway, made by an as yet undetermined large mammal, is described from the Lacombe Member (Late Paleocene) of the Paskapoo Formation (Paleocene). The exposure of the trackway was connected with the record-setting floods of 2013 in the province of Alberta as the tracks were exposed close to the base of the Brazeau Dam in west-central Alberta. The tracks are preserved on the top surface of a siltstone, but extensive erosion of the tracks resulted in the removal of details such as claw and digit traces, as well as any heel or palm impressions. The tracks are all circular to subcircular in outline, and it is not possible to determine the direction of travel of the trackmaker. Sequences of distinct pairings of adjacent tracks on both the left and right set of traces are present, and these are interpreted to represent manus-pes couples. The tracks do not show any overprinting. The mean pace angulations of the two best preserved sections range from 113\u00b0 to 125\u00b0, while their mean stride lengths range from 95 to 96 cm. The lack of any distinctive anatomical details being preserved in the tracks prevents a precise identification of the trackmaker, but the sizes, shapes, and age of the tracks suggest that they could have been made by a large pantodont.", "keyphrases": ["trackway", "paleocene", "alberta", "large mammal"]}
{"id": "paleo.002826", "title": "A new species of early Cambrian arthropod reconstructed from exceptionally preserved mandibles and associated small carbonaceous fossils (SCFs)", "abstract": "Mandibulate arthropods (myriapods, hexapods and crustaceans) account for a major component of extant animal diversity but their origins remain unclear. Here, we re\u2010examine the record of exceptionally preserved arthropodan microfossils, including mandibles, from the lower Cambrian (Stage 4) Mount Clark Formation, Northwest Territories, Canada. The assemblage comes from a single drillcore horizon and occurs as thousands of small carbonaceous fossils (SCFs) representing disarticulated body parts. The mandibles occur as isolated molar surfaces with an elongate outline, a heavy setal fringe, and a subtle right\u2013left asymmetry. These are sufficiently distinctive to diagnose a new genus and species of arthropod, Masticaris fimbriata. Co\u2010occurring SCFs include diverse appendage lobes and ventral body fragments, along with spines and setae assignable to 53 morphological categories and occurring either singly or in arrays, including filter plates. Most are plausibly interpreted as belonging to the feeding apparatus of M.\u2009fimbriata. The mandibles and filter plates correspond to those in extant pancrustaceans, particularly branchiopods, although the mouthparts of some more basal Cambrian arthropods raise the possibility of convergent feeding adaptations. Overall, anatomical and taphonomic continuity with younger SCFs suggests that M.\u2009fimbriata belongs to an early pancrustacean radiation that is still largely cryptic in the fossil record. More generally, the assemblage provides an inventory of fine\u2010scale cuticular specializations in early Cambrian arthropods that prefigure the trophic versatility and ecological dominance of crustaceans in the modern marine fauna.", "keyphrases": ["early cambrian arthropod", "mandible", "carbonaceous fossil"]}
{"id": "10.1002/ajpa.1330870105", "title": "Porotic hyperostosis: a new perspective.", "abstract": "Porotic hyperostosis is a paleopathologic condition that has intrigued researchers for over a century and a half. It is now generally accepted that anemia, most probably an iron deficiency anemia, is the etiologic factor responsible for lesion production. Although there can be a number of factors involved in the development of iron deficiency anemia, a dietary explanation has often been invoked to explain the occurrence of porotic hyperostosis in past human skeletal populations. In fact, porotic hyperostosis has been referred to as a \"nutritional\" stress indicator. Traditionally those groups with a higher incidence of porotic hyperostosis have been considered to be less successful in adapting to their environment or more nutritionally disadvantaged than other groups. A new perspective is emerging that is challenging previous views of the role of iron in health and disease, thus having profound implications for the understanding of porotic hyperostosis. There is a new appreciation of the adaptability and flexibility of iron metabolism; as a result it has become apparent that diet plays a very minor role in the development of iron deficiency anemia. It is now understood that, rather than being detrimental, hypoferremia (deficiency of iron in the blood) is actually an adaptation to disease and microorganism invasion. When faced with chronic and/or heavy pathogen loads individuals become hypoferremic as part of their defense against these pathogens, thus increasing their susceptibility to iron deficiency anemia. Within the context of this new perspective porotic hyperostosis is seen not as a nutritional stress indicator, but as a indication that a population is attempting to adapt to the pathogen load in its environment.", "keyphrases": ["new perspective", "disease", "porotic hyperostosis"]}
{"id": "paleo.010494", "title": "Total-Evidence Dating under the Fossilized Birth\u2013Death Process", "abstract": "Bayesian total-evidence dating involves the simultaneous analysis of morphological data from the fossil record and morphological and sequence data from recent organisms, and it accommodates the uncertainty in the placement of fossils while dating the phylogenetic tree. Due to the flexibility of the Bayesian approach, total-evidence dating can also incorporate additional sources of information. Here, we take advantage of this and expand the analysis to include information about fossilization and sampling processes. Our work is based on the recently described fossilized birth\u2013death (FBD) process, which has been used to model speciation, extinction, and fossilization rates that can vary over time in a piecewise manner. So far, sampling of extant and fossil taxa has been assumed to be either complete or uniformly at random, an assumption which is only valid for a minority of data sets. We therefore extend the FBD process to accommodate diversified sampling of extant taxa, which is standard practice in studies of higher-level taxa. We verify the implementation using simulations and apply it to the early radiation of Hymenoptera (wasps, ants, and bees). Previous total-evidence dating analyses of this data set were based on a simple uniform tree prior and dated the initial radiation of extant Hymenoptera to the late Carboniferous (309 Ma). The analyses using the FBD prior under diversified sampling, however, date the radiation to the Triassic and Permian (252 Ma), slightly older than the age of the oldest hymenopteran fossils. By exploring a variety of FBD model assumptions, we show that it is mainly the accommodation of diversified sampling that causes the push toward more recent divergence times. Accounting for diversified sampling thus has the potential to close the long-discussed gap between rocks and clocks. We conclude that the explicit modeling of fossilization and sampling processes can improve divergence time estimates, but only if all important model aspects, including sampling biases, are adequately addressed.", "keyphrases": ["birth\u2013death", "tree", "fossil taxa", "fbd model", "total-evidence"]}
{"id": "10.1098/rspb.2015.1530", "title": "No deep diving: evidence of predation on epipelagic fish for a stem beaked whale from the Late Miocene of Peru", "abstract": "Although modern beaked whales (Ziphiidae) are known to be highly specialized toothed whales that predominantly feed at great depths upon benthic and benthopelagic prey, only limited palaeontological data document this major ecological shift. We report on a ziphiid\u2013fish assemblage from the Late Miocene of Peru that we interpret as the first direct evidence of a predator\u2013prey relationship between a ziphiid and epipelagic fish. Preserved in a dolomite concretion, a skeleton of the stem ziphiid Messapicetus gregarius was discovered together with numerous skeletons of a clupeiform fish closely related to the epipelagic extant Pacific sardine (Sardinops sagax). Based on the position of fish individuals along the head and chest regions of the ziphiid, the lack of digestion marks on fish remains and the homogeneous size of individuals, we propose that this assemblage results from the death of the whale (possibly via toxin poisoning) shortly after the capture of prey from a single school. Together with morphological data and the frequent discovery of fossil crown ziphiids in deep-sea deposits, this exceptional record supports the hypothesis that only more derived ziphiids were regular deep divers and that the extinction of epipelagic forms may coincide with the radiation of true dolphins.", "keyphrases": ["epipelagic fish", "whale", "late miocene", "ziphiidae"]}
{"id": "10.1098/rspb.2010.2233", "title": "History matters: ecometrics and integrative climate change biology", "abstract": "Climate change research is increasingly focusing on the dynamics among species, ecosystems and climates. Better data about the historical behaviours of these dynamics are urgently needed. Such data are already available from ecology, archaeology, palaeontology and geology, but their integration into climate change research is hampered by differences in their temporal and geographical scales. One productive way to unite data across scales is the study of functional morphological traits, which can form a common denominator for studying interactions between species and climate across taxa, across ecosystems, across space and through time\u2014an approach we call \u2018ecometrics\u2019. The sampling methods that have become established in palaeontology to standardize over different scales can be synthesized with tools from community ecology and climate change biology to improve our understanding of the dynamics among species, ecosystems, climates and earth systems over time. Developing these approaches into an integrative climate change biology will help enrich our understanding of the changes our modern world is undergoing.", "keyphrases": ["ecometric", "climate change biology", "dynamic"]}
{"id": "10.1146/annurev.earth.36.031207.124146", "title": "The Fin to Limb Transition: New Data, Interpretations, and Hypotheses from Paleontology and Developmental Biology", "abstract": "After a brief historical review of the fin to limb transition and consideration of a theoretical \u201cprototetrapod,\u201d this article considers new ideas generated from recent fossil finds and from developmental biology that bear on the question of how limbs, digits, limb joints, and pentadactyly evolved. Among the first changes to take place were those to the humerus, in concert with those to the breathing apparatus, and these adaptations were acquired while the animals were still basically aquatic with the evolution of digits occurring during this phase. Studies from developmental biology of modern taxa can be integrated with information from fossils to produce a fuller picture. The acquisition of pentadactyly was among the last changes to occur in the modification of a fin into a limb. This vision differs radically from older theoretical ideas which perceived land locomotion as the prime evolutionary force driving the transition.", "keyphrases": ["fin", "limb transition", "developmental biology"]}
{"id": "paleo.005836", "title": "Insect mimicry of plants dates back to the Permian", "abstract": "In response to predation pressure, some insects have developed spectacular plant mimicry strategies (homomorphy), involving important changes in their morphology. The fossil record of plant mimicry provides clues to the importance of predation pressure in the deep past. Surprisingly, to date, the oldest confirmed records of insect leaf mimicry are Mesozoic. Here we document a crucial step in the story of adaptive responses to predation by describing a leaf-mimicking katydid from the Middle Permian. Our morphometric analysis demonstrates that leaf-mimicking wings of katydids can be morphologically characterized in a non-arbitrary manner and shows that the new genus and species Permotettigonia gallica developed a mimicking pattern of forewings very similar to those of the modern leaf-like katydids. Our finding suggests that predation pressure was already high enough during the Permian to favour investment in leaf mimicry.", "keyphrases": ["permian", "plant mimicry", "insect", "old case"]}
{"id": "paleo.001063", "title": "A symbiotic association of a boring polychaete and an echinoid from the Late Cretaceous of Germany", "abstract": "From the Early Maastrichtian white chalk of R\u00fcgen Island (N Germany), a specimen of the echinoid Echinocorys ovata featuring 27 boring traces of the ichnogenus Caulostrepsis is described. Individual traces are shallow to moderately deep U-shaped depressions and show distinct regeneration textures evidencing a syn-vivo infestation. All traces are located on the plastron between the peristome and periproct of the host echinoid, indicating an adaptation of the trace maker by choosing the most advantageous position of the specific host. The traces are attributed to the work of boring spionid polychaetes (Polydora complex), grounded on the close morphological resemblance with initial borings of Recent polydorids. This is the first evidence for a possible association of a boring polychaete not only with an echinoid but with an echinoderm in general. The symbiotic relationship was commensalistic in nature with the spionid probably taking advantage of organic matter resuspended by the echinoids locomotion and feeding activity and benefiting from effective shelter. For the host echinoid, the association was moderately harmful. The soft bottom environment of the chalk sea provided very limited hard substrate ecospace for settlers and bioeroders, available only in form of biogenic structures. Echinocorys was a dominant component of this benthic community and can be considered as a suitable host for symbiotic interactions because of its size and assumed longevity.", "keyphrases": ["boring polychaete", "polychaete", "echinoid"]}
{"id": "10.1080/14772019.2017.1353549", "title": "Prolonged co-existence of \u2018archaic\u2019 and \u2018modern\u2019 Palaeozoic ophiuroids \u2013 evidence from the early Permian, Southern Carnarvon Basin, Western Australia", "abstract": "The discovery of a very large ophiuroid (disk diameter of 80 mm) in the early Permian (Kungurian) Cundlego Formation in the Southern Carnarvon Basin of Western Australia extends the stratigraphical range of \u2018archaic\u2019 ophiuroids unequivocally into the Permian, unlocking a lost fossil record of this group. Hitherto such ophiuroids have been discovered preserved articulated from strata no younger than the late Carboniferous. Herein we describe the new ophiuroid as Teleosaster creasyi gen. et sp. nov. Although existing temporally with Permian ophiuroids with a \u2018modern\u2019 morphological architecture, Teleosaster was biogeographically separated. This \u2018archaic\u2019 ophiuroid persisted in high latitude seas, suggesting such \u2018archaic\u2019 forms were displaced from the shallow-water, low latitude niches by the \u2018modern\u2019 ophiuroids. In modern oceans, ophiuroid gigantism similar to that in Teleosaster creasyi is typically only expressed in cold, high latitude oceans. It has been argued that the frequent occurrence of gigantism in such environments is due to the much lower levels of predation pressure. Unlike other echinoderm classes, the morphological and ecological transformation that resulted in the evolution of \u2018modern\u2019 ophiuroids had already taken place well before the events of the Permo\u2013Triassic mass extinction. With the increase in diversity of durophagous predators in low latitude shallow-water communities during the mid-Palaeozoic Marine Revolution, we argue that \u2018archaic\u2019 ophiuroids were more susceptible to these higher levels of predation than the \u2018modern\u2019 forms and were displaced into regimes of lower predation pressure in high latitude oceans. http://zoobank.org/urn:lsid:zoobank.org:pub:E4FD9264-127D-4995-AD12-C9721F212FCD", "keyphrases": ["palaeozoic ophiuroid", "ophiuroid", "southern carnarvon basin"]}
{"id": "10.1111/1475-4983.00080", "title": "Feeding habits in trilobites", "abstract": "We briefly review the various types of feeding habits in marine arthropods, and suggest that the trilobites adopted a range of different feeding strategies. We show that much of the variety of trilobite exoskeletal development, particularly in the cephalon, can be explained as a response to the adoption of specific feeding modes. We regard the primitive mode as having been predatory/scavenging, both from morphological grounds and by out-group comparison, but this habit had a long subsequent history in the group. Predators/scavengers included those trilobites with rigidly braced and attached conterminant or impendent hypostomes, which often developed posterior forks or rasps used by the animals for manipulating prey after it had been grasped by the \u2018gnathobases\u2019. Advanced predators often acquired expanded anterior glabellar lobes which are associated with the ingestion of bulky food; concomitantly, the largest trilobites of all had predatory morphology. Associated trace fossils are of the Rusophycus type in which impressions of limb bases and rarely the hypostome can be seen. Detritivors were derived from predators by detachment of the hypostome from the doublure in natant mode; it is significant that the hypostome of such feeders exhibited little change thereafter. The typical detritivor morphology is of the \u2018generalized\u2019 ptychopariid type, common in outer shelf habitats, with rectangular or tapering glabellas and small to moderate overall size. It is suggested that in some species the hypostome may have functioned as a \u2018scoop\u2019 directly to aid ingestion of sediment. Trace fossils of Cruziana semiplicatatype have been associated with sediment ploughing in this feeding mode. Filter feeders evolved a vaulted cephalic chamber of trinucleimorph type, and elevated thoraces, often flanked by extended genal spines. Where it is known, the hypostome is curved up inside the cephalic chamber, within which sediment stirred into suspension by the limbs was sorted for edible particles. Filter feeding trilobites are typically small, and are uncommon outside muddy habitats. Bean-likeRusophycusare the associated trace fossils. In trinucleids ingress of the feeding current was alongside the thorax and out through the fringe pits. The combination of different feeding modes with adaptation for different prey and/or particle sizes goes some way to account for the variety of trilobites cohabiting in a single site (alpha diversity). We do not claim that the model accounts for all morphological variation displayed by the group. TR I L O B I T E S are remarkable for their great variety of exoskeletal shapes. Their morphological complexity increased from the Cambrian into the Ordovician (Fortey and Owens 1990; Foote 1991), and a considerable array of forms persisted even into the Carboniferous. Yet comparatively little is known about how this morphological variety related to life habits. It is common to find reference to certain phases of trilobite history as \u2018radiations\u2019, for example, at the beginning of the Cambrian (Briggs and Fortey 1992), through much of the Ordovician (Droser t al. 1996) and in the Malvinokaffric Province of the Devonian (Eldredge 1980), yet although the implication clearly is that radiations were into a variety of niches, it is unclear what these niches were, nor whether the morphological compass displayed can be related to their life habits. Broad habitat differentiation is better known. It is clear that the trilobites were able to occupy normal marine habitats (biofacies) ranging from near inshore, to deep water, even \u2018slope\u2019 environments, at several hundred metres of water depth, from early in the Cambrian until the later Carboniferous (review in Fortey and Owens 1997). This differentiation accounts for some of the richness in species of trilobites of any given geological age, but it does not account for the subdivision of each habitat by its constituent species (alpha diversity). Biofacies can vary in the number of species and genera they include, but it is not uncommon for a single biofacies to include 20 or more benthic taxa (e.g. Ludvigsen et al. 1989). Presumably, such co-occurring species found ways of exploiting their total environment which allowed them to compete adequately with their neighbours. The kinds of niche subdivisions of habitat which were possible for trilobites have been little investigated (Bergstr\u00f6m 1973). For such an extinct arthropod group, particularly one of which the appendages of so few species are known, the interpretation of life habits is not an easy matter. However, this should not prevent attempts to interpret reasonably function from form. This paper presents a model for trilobite feeding [Palaeontology, Vol. 42, Part 3, 1999, pp. 429\u2013465] q The Palaeontological Association habits, with an aim of answering one of the commonest questions advanced about the group: why many different kinds of trilobites co-exist in the same rock bed. Not all trilobites were benthic; a free swimming fauna also lived within the water column, at least during the Cambrian and Ordovician (Robison 1972; Fortey 1985; Fortey and Owens 1987). Robison (1975) explained the co-occurrence of differently sized planktic agnostids as resource partitioning, whereby adult trilobite size reflected optimal utilization of different food particle sizes, thus relating taxonomic variety and aspects of morphology to feeding specialization. However, there are often references to feeding mode in otherwise morphological and taxonomic accounts, and we have attempted to review the scattered literature of the past 50 years in this paper. Such a review should be of use to the non-specialist palaeontologist for teaching purposes. Our prime purpose is to identify a number of morphological designs connected with different feeding habits, discuss their geological history, and associate them broadly with their appropriate trace fossils. T H E R A N G E O F P O S S I B I L I T I E S F O R T R I L O B I T E F E E D I N G H A B I T S Marine arthropods occupy many different niches, and not all of these are capable of being deduced from fossil evidence. There is no necessary relationship between belonging to a particular high level taxon and having a specific life habit. Virtually all larger Arachnida, for example, are predatory in habit, while crustaceans may be filter feeders, sediment feeders, parasites, or predators (Schram 1986). Even within a single crustacean group (e.g. Cladocera, see Fryer 1968) there may be a variety of feeding habits. Hence the recognition of the feeding habits of one species is no guarantee that the rest of the group to which it belongs will have similar habits. For trilobites, we are perforce concerned only with the broadest categories of feeding strategies, and we cannot approach the refinements known for the living fauna. To give one example, Laval (1980) describes how hyperiid amphipods have evolved a close relationship with medusoids and ctenophores, using them as a nursery for young, or in some cases killing them to construct their own floating accommodation. Such habits will forever elude palaeontological evidence. In the sections that follow, the attitude and position of the trilobite hypostome will be of importance. Throughout the rest of this paper we accept the commonly held view that the trilobite\u2019s mouth lay at the back of the hypostome, and that the oesophagus lay above it. The oesophagus opened into the stomach situated beneath the glabella, especially its anterior part. The oesophagus was elevated or contracted by muscles which attached between the hypostome and the oesophagal wall. This is an arrangement similar to that described for the living notostracan Lepidurus arcticusby Fryer (1988, fig. 63). The life habits available to arthropods (and conceivably to trilobites) can be summarized briefly as follows: 1. Predatory. Hunting habits are common among crustaceans (e.g. Stomatopoda) and dominant in Arachnida.Limulusis capable of breaking clams with its gnathobasic jaws. There is a gradation between hunting activity and scavenging, and many crustaceans which are capable of hunting, e.g. among the decapods, are also opportunistic scavengers if the possibility arises. The manipulation of comparatively bulky food unites these two activities, and, because of the relatively high nutritional value of such food, larger arthropods tend to have such habits. We cannnot distinguish scavenging from predatory habits here. 2. Particle feeding. Feeding on edible detritus is a common mode of life among crustaceans, including branchiopods, ostracodes and isopods, among animals ranging from a few millimetres to a few tens of millimetres long (Brusca and Brusca 1990). Included in this category is feeding using the ventral median line as a food groove, such as has been described in the diminutive and primitive cephalocarid Hutchinsoniella by Sanders (1963). Sorting of edible from inedible particles is achieved by the appendages. A variant on this life mode is scraping or collecting edible material, usually algal, directly from rocks or sedimentary surfaces. 3. Suspension feeding. Many arthropods, notostracans, conchostracans and phyllocarids among them, stir up sediment in order to extract edible organic particles, or they exploit algal \u2018soup\u2019 in similar fashion. The notostracanTriops, for example, stirs up clouds of sediment beneath its dorsal carapace, and passes the edible particles sorted from suspension towards the mouth along the ventral food groove (Fryer 1988). One might suspect that this mode of life ought to be present among trilobites, especially in view of the similarity of the vaulted headshield of many species to that of Triops. 430 P A L A E O N T O L O G Y , V O L U M E 4 2", "keyphrases": ["habit", "trilobite", "arthropod", "feeder"]}
{"id": "paleo.011802", "title": "Allometric growth in the extant coelacanth lung during ontogenetic development", "abstract": "Coelacanths are lobe-finned fishes known from the Devonian to Recent that were long considered extinct, until the discovery of two living species in deep marine waters of the Mozambique Channel and Sulawesi. Despite extensive studies, the pulmonary system of extant coelacanths has not been fully investigated. Here we confirm the presence of a lung and discuss its allometric growth in Latimeria chalumnae, based on a unique ontogenetic series. Our results demonstrate the presence of a potentially functional, well-developed lung in the earliest known coelacanth embryo, and its arrested growth at later ontogenetic stages, when the lung is clearly vestigial. The parallel development of a fatty organ for buoyancy control suggests a unique adaptation to deep-water environments. Furthermore, we provide the first evidence for the presence of small, hard, flexible plates around the lung in L. chalumnae, and consider them homologous to the plates of the \u2018calcified lung' of fossil coelacanths.", "keyphrases": ["coelacanth", "lung", "latimeria chalumnae", "allometric growth"]}
{"id": "paleo.004341", "title": "Jaws for a spiral-tooth whorl: CT images reveal novel adaptation and phylogeny in fossil Helicoprion", "abstract": "New CT scans of the spiral-tooth fossil, Helicoprion, resolve a longstanding mystery concerning the form and phylogeny of this ancient cartilaginous fish. We present the first three-dimensional images that show the tooth whorl occupying the entire mandibular arch, and which is supported along the midline of the lower jaw. Several characters of the upper jaw show that it articulated with the neurocranium in two places and that the hyomandibula was not part of the jaw suspension. These features identify Helicoprion as a member of the stem holocephalan group Euchondrocephali. Our reconstruction illustrates novel adaptations, such as lateral cartilage to buttress the tooth whorl, which accommodated the unusual trait of continuous addition and retention of teeth in a predatory chondrichthyan. Helicoprion exemplifies the climax of stem holocephalan diversification and body size in Late Palaeozoic seas, a role dominated today by sharks and rays.", "keyphrases": ["whorl", "phylogeny", "jaw"]}
{"id": "10.1360/02tb9082", "title": "The genesis and environmental significance of red and black sedimentary interlayers in coral reef of well Nanyong 2", "abstract": "The results of paleogeomagnetics and geochemistry of the coral reef in well Nanyong 2 of Nansha Islands showed that the bottom of the black sedimentary interlayer corresponds to the conversion boundary line between Brunhes Postive Polarity and Matuyama Reversed Polarity (B/M) and the cold/warm (19/20) climatic conversion bounds on \u03b418O curve, 0.78 Ma ago; and the red sedimentary interlayer corresponds to the Reunion I polarity excursion (reversion) of the geomagnetic field, 2.01\u20132.04 Ma ago. Comparing with the normal light-coloured coral reef rock, the magnetic susceptibility (\u03c7), residual magnetization intensity (Mr) and the content of MnO and Fe2O3 of the black sedimentary layer appeared obviously positive abnormity. The magnetic susceptibility (\u03c7), residual magnetization intensity (Mr) and the content of Fe2O3 of the red sedimentary layer also appeared positive abnormity. Combining with the analyzing results of paleontology, we hold that this pair of special and typical sedimentary interlayers was relative to the sudden change of paleoclimate, i.e. the global climatic change and its incidental polarity reversal of the geomagnetic field directly affected the living environment of the paleontological species as well as the dispersion and enrichment of some chemical elements, especially the elements sensitive to redox such as Fe and Mn. For example, the elements Fe and Mn concentrated in the glacial period would be largely oxidized and diluted when the climate warmed up suddenly, and the originally oxidized high valence Fe would be condensed again when the climate cooled suddenly. This is possibly one of the important reasons of appearing and disappearing of the red and black sedimentary events of coral reef in well Nanyong 2.", "keyphrases": ["sedimentary interlayer", "coral reef", "nansha islands"]}
{"id": "10.1080/03115510108619215", "title": "Early Silurian (Llandovery) trilobites from the Cotton Formation, near Forbes, New South Wales, Australia", "abstract": "A trilobite fauna from the upper part of the Cotton Formation (late Llandovery, Spirograptus turriculatus Zone) in central west New South Wales includes the new species Raphiophorus sandfordi, Odontopleura (Sinespinaspis) markhami and Aulacopleura pogsoni. Species of Odontopleura and Aulacopleura have not previously been documented in Australasia. The association of these genera is observed in offshore biofacies in the Llandovery/Wenlock on several palaeocontinents. Affinities of the species are with congeners from Bohemia and northwestern Canada (Odontopleura, Aulacopleura) and Tarim and South China (Aulacopleura, Raphiophorus).", "keyphrases": ["llandovery", "cotton formation", "new south wales"]}
{"id": "paleo.004651", "title": "Exceptional preservation of reproductive organs and giant sperm in Cretaceous ostracods", "abstract": "The bivalved crustacean ostracods have the richest fossil record of any arthropod group and display complex reproductive strategies contributing to their evolutionary success. Sexual reproduction involving giant sperm, shared by three superfamilies of living ostracod crustaceans, is among the most fascinating behaviours. However, the origin and evolution of this reproductive mechanism has remained largely unexplored because fossil preservation of such features is extremely rare. Here, we report exceptionally preserved ostracods with soft parts (appendages and reproductive organs) in a single piece of mid-Cretaceous Kachin amber (approximately 100 Myr old). The ostracod assemblage is composed of 39 individuals. Thirty-one individuals belong to a new species and genus, Myanmarcypris hui gen. et sp. nov., exhibiting an ontogenetic sequence from juveniles to adults (male and female). Seven individuals are assigned to Thalassocypria sp. (Cypridoidea, Candonidae, Paracypridinae) and one to Sanyuania sp. (Cytheroidea, Loxoconchidae). Our micro-CT reconstruction provides direct evidence of the male clasper, sperm pumps (Zenker organs), hemipenes, eggs and female seminal receptacles with giant sperm. Our results reveal that the reproduction behavioural repertoire, which is associated with considerable morphological adaptations, has remained unchanged over at least 100 million years\u2014a paramount example of evolutionary stasis. These results also double the age of the oldest unequivocal fossil animal sperm. This discovery highlights the capacity of amber to document invertebrate soft parts that are rarely recorded by other depositional environments.", "keyphrases": ["reproductive organ", "giant sperm", "ostracod"]}
{"id": "10.1111/evo.12884", "title": "Sampling diverse characters improves phylogenies: Craniodental and postcranial characters of vertebrates often imply different trees", "abstract": "Morphological cladograms of vertebrates are often inferred from greater numbers of characters describing the skull and teeth than from postcranial characters. This is either because the skull is believed to yield characters with a stronger phylogenetic signal (i.e., contain less homoplasy), because morphological variation therein is more readily atomized, or because craniodental material is more widely available (particularly in the palaeontological case). An analysis of 85 vertebrate datasets published between 2000 and 2013 confirms that craniodental characters are significantly more numerous than postcranial characters, but finds no evidence that levels of homoplasy differ in the two partitions. However, a new partition test, based on tree\u2010to\u2010tree distances (as measured by the Robinson Foulds metric) rather than tree length, reveals that relationships inferred from the partitions are significantly different about one time in three, much more often than expected. Such differences may reflect divergent selective pressures in different body regions, resulting in different localized patterns of homoplasy. Most systematists attempt to sample characters broadly across body regions, but this is not always possible. We conclude that trees inferred largely from either craniodental or postcranial characters in isolation may differ significantly from those that would result from a more holistic approach. We urge the latter.", "keyphrases": ["postcranial character", "vertebrate", "homoplasy"]}
{"id": "paleo.001483", "title": "Burrows without a trace\u2014How meioturbation affects rock fabrics and leaves a record of meiobenthos activity in shales and mudstones", "abstract": "Understanding fine-grained sediment accumulation is critical for developing robust geologic models and inferring environmental conditions. Here we report on processes that produce compositional layering at the mm and sub-mm scale, with gradational rather than sharp layer boundaries. Sometimes described as fuzzy laminae, this feature occurs in modern muds that accumulate under oxygen-stressed conditions, caused by meiofauna (tiny organisms; benthic foraminifera, polychaetes, nematodes, etc.) that disrupts the original fabric. In the rock record, fuzzy laminae are common in shales that accumulated under presumed oxygen-stressed conditions. Like their presumed modern analogs, ancient examples contain remains of benthic foraminifera and other small benthic organisms that were the likely agents of fabric disruption. As preserved lamination is considered indicative of bottom water anoxia in ancient shales, we need to better understand the cause of fuzzy lamination, because such insights have the potential to allow much refined assessments of the depositional history of laminated organic-rich shales. In experiments, nematode activity blurred the originally sharp contacts between successive sediment layers with contrasting composition. Although nematode activity produces tiny temporary traces aside of blurring of primary fabric, the former have minimal preservation potential due to compaction of the water-rich substrate. Experimental fabrics compare well to those observed in a wide range of ancient black shales, suggesting common meiofaunal activity in the latter. Our findings imply that the details of lamination (fuzzy vs. sharp) in ancient shales are not necessarily controlled by bottom water oxygenation, but instead result from the interplay between sedimentation rates and bottom current activity.", "keyphrases": ["activity", "shale", "mudstone"]}
{"id": "10.24199/j.mmv.2016.74.03", "title": "Cretaceous marine amniotes of Australia: perspectives on a decade of new research", "abstract": "Kear, B.P. 2016. Cretaceous marine amniotes of Australia: perspectives on a decade of new research. Memoirs of Museum Victoria 74: 17\u201328. Cretaceous marine amniote fossils have been documented from Australia for more than 150 years, however, their global significance has only come to the fore in the last decade. This recognition is a product of accelerated research coupled with spectacular new discoveries from the Aptian\u2013Albian epeiric sequences of the Eromanga Basin \u2013 especially the opal-bearing deposits of South Australia and vast lagerst\u00e4tten exposures of central-northern Queensland. Novel fragmentary records have also surfaced in Cenomanian and Maastrichtian strata from Western Australia. The most notable advances include a proliferation of plesiosaurian taxa, as well as detailed characterization of the \u2018last surviving\u2019 ichthyosaurian Platypterygius, and some of the stratigraphically oldest protostegid sea turtles based on exceptionally preserved remains. Compositionally, the Australian assemblages provide a unique window into the otherwise poorly known Early Cretaceous marine amniote faunas of Gondwana. Their association with freezing high latitude palaeoenvironments is also extremely unusual, and evinces a climate change coincident diversity turnover incorporating the nascent radiation of lineages that went on to dominate later Mesozoic seas.", "keyphrases": ["australia", "new research", "cretaceous marine amniote"]}
{"id": "10.1080/02724634.2018.1536664", "title": "A novel archosauromorph from Antarctica and an updated review of a high-latitude vertebrate assemblage in the wake of the end-Permian mass extinction", "abstract": "Abstract Triassic-aged fossil vertebrates have been sporadically collected from the Fremouw Formation, central Transantarctic Mountains, since their initial discovery in the late 1960s, giving paleontologists insight into high-latitude faunas in the wake of the end-Permian mass extinction event. On a recent expedition (2010\u20132011), a small reptile skeleton was collected from Graphite Peak, which we present here alongside novel geological data and interpretations taken on site. Antarctanax shackletoni, gen. et sp. nov., is known from a partial postcranial skeleton including cervical and dorsal vertebrae, a humerus, and both pedes. Important morphological information includes well-defined laminae and deep fossae on cervicodorsal vertebrae. The new taxon can be differentiated from previously known Fremouw Formation reptiles (e.g., Prolacerta, Procolophon), as well as those from the Karoo Basin, South Africa (e.g., Mesosuchus, Proterosuchus, Euparkeria). Our inclusion of A. shackletoni in phylogenetic analyses of early amniotes finds it as an archosauriform archosauromorph, increasing known archosauriform diversity in the Early Triassic. The fauna of the lower Fremouw Formation traditionally has been considered to represent a subset of the Lystrosaurus Assemblage Zone of the Karoo Basin, with differences largely a result of pronounced differences in sampling intensity. However, a review of recent changes to the fauna, as well as a reassessment of occurrences based on older literature, indicates that significant discrepancies, including the co-occurrences of taxa known from both earlier and later in time and the presence of endemic forms in Antarctica, exist between the faunas of the Lystrosaurus Assemblage Zone and lower Fremouw Formation. http://zoobank.org/urn:lsid:zoobank.org:pub:B1DAD1A4-7054-454D-89B2-17CAF2865AD4 SUPPLEMENTAL DATA\u2014Supplemental materials are available for this article for free at www.tandfonline.com/UJVP Citation for this article: Peecook, B. R., R. M. H. Smith, and Christian A. Sidor. 2019. A novel archosauromorph from Antarctica and an updated review of a high-latitude vertebrate assemblage in the wake of the end-Permian mass extinction. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2018.1536664.", "keyphrases": ["review", "high-latitude vertebrate assemblage", "end-permian mass extinction"]}
{"id": "10.1144/jgs2018-088", "title": "The Mazon Creek Lagerst\u00e4tte: a diverse late Paleozoic ecosystem entombed within siderite concretions", "abstract": "One of the best records of late Paleozoic ecosystems, the Mazon Creek Lagerst\u00e4tte is world famous for its striking flora and fauna preserved within siderite concretions. Distinct from other late Carboniferous concretionary Lagerst\u00e4tten because of the remarkable fidelity of soft tissues and pigments that are frequently preserved, the Mazon Creek has seen a revival in investigations during the last 10\u2005years using modern palaeontological techniques. However, many of these modern investigations build upon a literature that incorrectly interprets the palaeoenvironment of the Mazon Creek and the separate biotas: there is a lack of evidence to support a distinct freshwater fauna. Here, we present a detailed overview of the Mazon Creek Lagerst\u00e4tte, including the palaeoenvironmental conditions, organisms present and the complex taphonomic processes involved in fossil formation. Investigation into the formation of siderite concretions and the complex taphonomic processes controlling soft-bodied preservation are still continuing but are reviewed in detail.", "keyphrases": ["mazon creek lagerst\u00e4tte", "paleozoic ecosystem", "concretion"]}
{"id": "10.1017/jpa.2018.20", "title": "The Earliest Elcanidae (Insecta, Orthoptera) from the Upper Triassic of North America", "abstract": "Abstract. A new genus and species of the Elcanidae (Orthoptera, Elcanoidea), Cascadelcana virginiana n. gen. n. sp., is described based on a forewing specimen from the Upper Triassic (Norian) Cow Branch Formation in the Solite Quarry Lagerst\u00e4tte near the North Carolina-Virginia boundary, USA. It is distinguished from other elcanid species by its RP +MA1 with six branches, M with two branches before stem MA1 fused with RP, and short CuA almost vertical against the posterior margin. This fossil represents the earliest definitive record of the family Elcanidae and the first orthopteran described from the Triassic of North America. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) analyses show that the veins and a pterostigma-like structure on the wing of C. virginiana n. gen. n. sp. are preserved as carbonaceous compressions. The presence of a pterostigma-like structure in elcanids indicates that they may have evolved a particular flight mechanism distinct from those of other orthopterans.", "keyphrases": ["orthoptera", "upper triassic", "north america"]}
{"id": "10.1080/02724634.2017.1299158", "title": "Libysiren sickenbergi, gen. et sp. nov.: A New Sirenian (Mammalia, Protosirenidae) from the Middle Eocene of Libya", "abstract": "ABSTRACT \n Fossil sirenian specimens collected in 1964 by the late R. J. G. Savage's expeditions in north-central Libya are described. They come from early middle Eocene (lower Lutetian, 47.8\u201343.6 Ma) deposits at the locality of Bu el Haderait and represent a new genus and species, Libysiren sickenbergi. This animal is the largest known protosirenid, and the largest Eocene sirenian known to date (condylobasal length >420 mm). Its dental formula was apparently 3.1.5.3, with five premolar loci as in all other Eocene sirenians, but the teeth are mostly not preserved. Its postcranial skeleton is unknown except for the atlas, a thoracic vertebra, and rib fragments. Stable isotopes indicate a mostly seagrass diet and a habitat of fully marine salinity. The Protosirenidae presently comprise the genera Protosiren, Ashokia, and Libysiren, with their interrelationships unresolved. Together, they are most parsimoniously regarded as a paraphyletic group basal to both Trichechidae and Dugongidae. However, as more of their morphology and diversity are revealed, they may prove to be more closely allied to the former and may shed crucial light on the still-mysterious origins of the trichechids (manatees).", "keyphrases": ["protosirenidae", "middle eocene", "libya"]}
{"id": "10.2110/palo.2012.p12-045r", "title": "TAPHONOMIC VARIABILITY OF FOSSIL INSECTS: A BIOSTRATINOMIC STUDY OF PALAEONTINIDAE AND TETTIGARCTIDAE (INSECTA: HEMIPTERA) FROM THE JURASSIC DAOHUGOU LAGERST\u00c4TTE", "abstract": "ABSTRACT Various intrinsic as well as extrinsic factors significantly control the preservation of insects. Few studies have presented a quantitative comparison of biostratinomic patterns in different groups, especially at the familial level. Here, we systematically investigated the preservation of 277 specimens of Palaeontinidae and 113 of Tettigarctidae, two hemipterous families from the Jurassic Daohugou beds lacustrine Konservat-Lagerst\u00e4tte. We carried out quantitative analyses of their size and taphonomic characters, including body orientation, articulation, and preservational quality, and also performed a preliminary experiment to understand the floating and decay process of cicadas. Our statistical analyses reveal significant differences in both body orientation and preservational quality between the two families. Palaeontinidae experienced longer flotation time (mostly over one month) before settling through the water column due to their high SM index (wing surface/body mass ratio) and unfolded wings, increasing the opportunity to decompose on the water surface and resulting in the dorsoventral preservation position with lower preservational quality. In contrast, Tettigarctidae have a comparatively low SM index and overlapping wings, so that their drifting period on the water surface might have been short (mostly within 2 weeks), leading to the lateral preservation position with higher preservational quality. Our results show that the wing-folding behavior and relative size of wings (SM index) influence the buoyancy times and significantly control the preservation patterns of both groups.", "keyphrases": ["insect", "palaeontinidae", "tettigarctidae"]}
{"id": "paleo.006590", "title": "The origin of annelids", "abstract": "Annelids are a phylum of segmented bilaterian animals that have become important components of ecosystems spanning terrestrial realms to the deep sea. Annelids are remarkably diverse, possessing high taxonomic diversity and exceptional morphological disparity, and have evolved numerous feeding strategies and ecologies. Their interrelationships and evolution have been the source of much controversy over the past century with the composition of the annelid crown group, the relationship of major groups and the body plan of the ancestral annelid having undergone major recent revisions. There is a convincing body of molecular evidence that polychaetes form a paraphyletic grade and that clitellates are derived polychaetes. The earliest stem group annelids from Cambrian Lagerst\u00e4tten are errant, epibenthic polychaetes, confirming that biramous parapodia, head appendages and diverse, simple chaetae are primitive for annelids. Current evidence from molecular clocks and the fossil record suggest that crown group annelids are a Late Cambrian \u2013 Ordovician radiation, with clitellates radiating in the Late Palaeozoic. Their body fossil record is largely confined to deposits showing exceptional preservation and is punctuated by the acquisition of hard parts in major groups. The discovery of an Ordovician fossil with soft tissues has shown that machaeridians are in fact a clade of crown polychaetes. They were in existence for more than 200 million years and possess unique calcitic dorsal armour, allowing their mode of life and phylogeny to be interpreted in the context of the annelid body plan. We identify a novel clade of machaeridians, the Cuniculepadida, which exhibit a series of adaptations for burrowing.", "keyphrases": ["annelid", "phylum", "polychaete", "chaeta", "exceptional preservation"]}
{"id": "paleo.007268", "title": "Macroevolutionary patterns in Rhynchocephalia: is the tuatara (Sphenodon punctatus) a living fossil?", "abstract": "The tuatara, Sphenodon punctatus, known from 32 small islands around New Zealand, has often been noted as a classic \u2018living fossil\u2019 because of its apparently close resemblance to its Mesozoic forebears and because of a long, low\u2010diversity history. This designation has been disputed because of the wide diversity of Mesozoic forms and because of derived adaptations in living Sphenodon. We provide a testable definition for \u2018living fossils\u2019 based on a slow rate of lineage evolution and a morphology close to the centroid of clade morphospace. We show that through their history since the Triassic, rhynchocephalians had heterogeneous rates of morphological evolution and occupied wide morphospaces during the Triassic and Jurassic, and these then declined in the Cretaceous. In particular, we demonstrate that the extant tuatara underwent unusually slow lineage evolution, and is morphologically conservative, being located near the centre of the morphospace for all Rhynchocephalia.", "keyphrases": ["rhynchocephalia", "sphenodon punctatus", "new zealand", "morphology"]}
{"id": "10.1002/evan.1360030505", "title": "The earliest primates", "abstract": "Remarkable new fossil discoveries and intensive study of fossil evidence has led, during the past decade, and particularly the last few years, to exceptional advances and modifications in our understanding of early primate evolution. New insights have also come from research on extant primates, especially detailed anatomical, functional, and molecular studies. This review, however, focuses on the paleontological evidence. New fossils are spawning novel, sometimes controversial ideas about the relationships within and among primates and their allies\u2014a situation that has caused temporary instability, but should eventually lead to elucidation, if not resolution, of outstanding problems.", "keyphrases": ["primate", "new fossil", "intensive study"]}
{"id": "10.1080/02724634.2016.1082480", "title": "New Carnivoraforms from the Latest Paleocene of Europe and Their Bearing on the Origin and Radiation of Carnivoraformes (Carnivoramorpha, Mammalia)", "abstract": "ABSTRACT \n We report the discovery of the earliest European carnivoraforms, based on two new taxa from the latest Paleocene of France and Romania. A new species of Vassacyon, V. prieuri, from the locality of Rivecourt (MP6b; Oise, France) (MP = Mammalian Paleogene reference levels) is described based on a dentary fragment and isolated teeth. This species displays several primitive features compared with species of Vassacyon known from the early Eocene of North America and Europe. A second Paleocene carnivoraform, cf. Gracilocyon sp., is described based on fragmentary specimens from the locality of Jibou (MP6b; Transylvania, Romania). Carnivoraformes were previously unknown in Europe before the Eocene, and Vassacyon prieuri and cf. Gracilocyon sp. are their oldest records in Europe. These discoveries favor the hypothesis of a dispersal of these two genera from Europe to North America during the Paleocene-Eocene Thermal Maximum. Vassacyon prieuri and cf. Gracilocyon sp. strengthen support for the level MP6b and its correlation with the Clarkforkian. The geographic origin of the Carnivoraformes remains unknown. However, based on the observed biochronological and geographic distributions of the carnivoraforms, we infer a possible Asian origin for this group. In this scenario, Gracilocyon and Vassacyon dispersed to Europe during the Clarkforkian MP6b time, probably together with rodent taxa, whereas Uintacyon dispersed from Asia to North America shortly after rodents and tillodonts.", "keyphrases": ["carnivoraformes", "europe", "carnivoramorpha", "late paleocene"]}
{"id": "10.1111/j.1420-9101.2010.02176.x", "title": "Paleogenomic data suggest mammal\u2010like genome size in the ancestral amniote and derived large genome size in amphibians", "abstract": "An unsolved question in evolutionary genomics is whether amniote genomes have been expanding or contracting since the common ancestor of this diverse group. Here, we report on the polarity of amniote genome size evolution using genome size estimates for 14 extinct tetrapod genera from the Paleozoic and early Mesozoic Eras using osteocyte lacunae size as a correlate. We find substantial support for a phylogenetically controlled regression model relating genome size to osteocyte lacunae size (P of slopes <\u20030.01, r2\u2003=\u20030.65, phylogenetic signal (\u03bb)\u2003=\u20030.83). Genome size appears to have been homogeneous across Paleozoic crown\u2010tetrapod lineages (average haploid genome size 2.9\u20133.7\u2003pg) with values similar to those of extant mammals. The differentiation in genome size and underlying architecture among extant tetrapod lineages likely evolved in the Mesozoic and Cenozoic Eras, with expansion in amphibians, contractions along the diapsid lineage, and no directional change within the synapsid lineage leading to mammals.", "keyphrases": ["genome size", "amniote", "amphibian"]}
{"id": "10.1002/ajpa.10019", "title": "Origin of human bipedalism: The knuckle-walking hypothesis revisited.", "abstract": "Some of the most long-standing questions in paleoanthropology concern how and why human bipedalism evolved. Over the last century, many hypotheses have been offered on the mode of locomotion from which bipedalism originated. Candidate ancestral adaptations include monkey-like arboreal or terrestrial quadrupedalism, gibbon- or orangutan-like (or other forms of) climbing and suspension, and knuckle-walking. This paper reviews the history of these hypotheses, outlines their predictions, and assesses them in light of current phylogenetic, comparative anatomical, and fossil evidence. The functional significance of characteristics of the shoulder and arm, elbow, wrist, and hand shared by African apes and humans, including their fossil relatives, most strongly supports the knuckle-walking hypothesis, which reconstructs the ancestor as being adapted to knuckle-walking and arboreal climbing. Future fossil discoveries, and a clear understanding of anthropoid locomotor anatomy, are required to ultimately test these hypotheses. If knuckle-walking was an important component of the behavioral repertoire of the prebipedal human ancestor, then we can reject scenarios on the origin of bipedalism that rely on a strictly arboreal ancestor. Moreover, paleoenvironmental data associated with the earliest hominins, and their close relatives, contradict hypotheses that place the agents of selection for bipedality in open savanna habitats. Existing hypotheses must explain why bipedalism would evolve from an ancestor that was already partly terrestrial. Many food acquisition and carrying hypotheses remain tenable in light of current evidence.", "keyphrases": ["bipedalism", "knuckle-walking hypothesis", "climbing", "pan"]}
{"id": "10.1080/02724634.1997.10010977", "title": "Bipedalism, flight, and the evolution of theropod locomotor diversity", "abstract": "ABSTRACT The evolution of theropod flight has been characterized as a shift from one to three locomotor modules. Basal theropods, which were terrestrial bipeds, had a single locomotor module composed of the hind limb and tail. In birds, aerial locomotion was acquired with the origination of the wing module and a decoupling of the hind limb and tail into separate pelvic and caudal modules. This increase in modularity is thought to have granted birds more locomotor \u201coptions\u201d than non-avian theropods. More specifically, an aerial locomotor system could have eased constraints on the hind limb and allowed specialization for habitats and lifestyles unavailable to non-birds. If so, bird hind limbs should be more disparate than those of non-avian theropods. We addressed this hypothesis by visualizing one aspect of limb design, the proportions of the three main segments, using ternary diagrams. Our results show that avian hind limb proportions are much more disparate than those of non-avian theropods. This broad r...", "keyphrases": ["flight", "bipedalism", "locomotor mode"]}
{"id": "paleo.002993", "title": "A small ichthyosaur from the Clearwater Formation (Alberta, Canada) and a discussion of the taxonomic utility of the pectoral girdle", "abstract": "Albian sedimentary successions of northwestern Canada have yielded a diverse assemblage of Mesozoic marine vertebrates, and ichthyosaurs form an important component of these faunas. Here, we describe a partial postcranial skeleton of a small (estimated at less than 3 m total body length) ichthyosaur from the Wabiskaw Member of the Clearwater Formation (lowermost Albian). The semi-articulated specimen includes much of the presacral vertebral column, dorsal ribs and gastralia. Most significantly, it possesses an articulated pectoral girdle and humerus, and also preserves the pelvic girdle, allowing new insights into girdle evolution in ichthyosaurs. Whereas both sets of girdles are thought to exhibit large amounts of intraspecific variation, the pectoral girdle of ophthalmosaurids appears to evolve very slowly, remaining essentially unchanged from the Middle Jurassic onwards. In contrast, the pelvic girdle shows taxonomically informative changes within Ophthalmosauridae. The variable and poorly known nature of girdle morphology in Cretaceous ichthyosaurs precludes generic referral of the specimen.", "keyphrases": ["ichthyosaur", "clearwater formation", "pectoral girdle"]}
{"id": "paleo.011720", "title": "Mineralization of Alvinella polychaete tubes at hydrothermal vents", "abstract": "Alvinellid polychaete worms form multilayered organic tubes in the hottest and most rapidly growing areas of deep\u2010sea hydrothermal vent chimneys. Over short periods of time, these tubes can become entirely mineralized within this environment. Documenting the nature of this process in terms of the stages of mineralization, as well as the mineral textures and end products that result, is essential for our understanding of the fossilization of polychaetes at hydrothermal vents. Here, we report in detail the full mineralization of Alvinella spp. tubes collected from the East Pacific Rise, determined through the use of a wide range of imaging and analytical techniques. We propose a new model for tube mineralization, whereby mineralization begins as templating of tube layer and sublayer surfaces and results in fully mineralized tubes comprised of multiple concentric, colloform, pyrite bands. Silica appeared to preserve organic tube layers in some samples. Fine\u2010scale features such as protein fibres, extracellular polymeric substances and two types of filamentous microbial colonies were also found to be well preserved within a subset of the tubes. The fully mineralized Alvinella spp. tubes do not closely resemble known ancient hydrothermal vent tube fossils, corroborating molecular evidence suggesting that the alvinellids are a relatively recent polychaete lineage. We also compare pyrite and silica preservation of organic tissues within hydrothermal vents to soft tissue preservation in sediments and hot springs.", "keyphrases": ["polychaete tube", "hydrothermal vent", "mineralization"]}
{"id": "10.1111/brv.12666", "title": "Assessing ontogenetic maturity in extinct saurian reptiles", "abstract": "Morphology forms the most fundamental level of data in vertebrate palaeontology because it is through interpretations of morphology that taxa are identified, creating the basis for broad evolutionary and palaeobiological hypotheses. Assessing maturity is one of the most basic aspects of morphological interpretation and provides the means to study the evolution of ontogenetic changes, population structure and palaeoecology, life\u2010history strategies, and heterochrony along evolutionary lineages that would otherwise be lost to time. Saurian reptiles (the least\u2010inclusive clade containing Lepidosauria and Archosauria) have remained an incredibly diverse, numerous, and disparate clade through their ~260\u2010million\u2010year history. Because of the great disparity in this group, assessing maturity of saurian reptiles is difficult, fraught with methodological and terminological ambiguity. We compiled a novel database of literature, assembling >900 individual instances of saurian maturity assessment, to examine critically how saurian maturity has been diagnosed. We review the often inexact and inconsistent terminology used in saurian maturity assessment (e.g. \u2018juvenile\u2019, \u2018mature\u2019) and provide routes for better clarity and cross\u2010study coherence. We describe the various methods that have been used to assess maturity in every major saurian group, integrating data from both extant and extinct taxa to give a full account of the current state of the field and providing method\u2010specific pitfalls, best practices, and fruitful directions for future research. We recommend that a new standard subsection, \u2018Ontogenetic Assessment\u2019, be added to the Systematic Palaeontology portions of descriptive studies to provide explicit ontogenetic diagnoses with clear criteria. Because the utility of different ontogenetic criteria is highly subclade dependent among saurians, even for widely used methods (e.g. neurocentral suture fusion), we recommend that phylogenetic context, preferably in the form of a phylogenetic bracket, be used to justify the use of a maturity assessment method. Different methods should be used in conjunction as independent lines of evidence when assessing maturity, instead of an ontogenetic diagnosis resting entirely on a single criterion, which is common in the literature. Critically, there is a need for data from extant taxa with well\u2010represented growth series to be integrated with the fossil record to ground maturity assessments of extinct taxa in well\u2010constrained, empirically tested methods.", "keyphrases": ["maturity", "saurian reptile", "literature"]}
{"id": "paleo.007910", "title": "Moulting, ontogeny and sexual dimorphism in the Cambrian ptychopariid trilobite Strenuaeva inflata from the northern Swedish Caledonides", "abstract": "Abstract:\u2002 Three thousand seven hundred disarticulated remains together with several articulated specimens of the Cambrian Series 2 ptychopariid trilobite Strenuaeva inflata Ahlberg and Bergstr\u00f6m, 1978 have been collected from the Tornetr\u00e4sk area, northern Sweden. The material provides significant new data on the morphology, ontogeny, moulting and enrolment of the species. Two distinct morphotypes, possibly an expression of sexual dimorphism, are recognized. The morph with a pair of bulbs in the frontal area, interpreted as brood pouches, is considered to represent females. Statistical treatment of the length/width ratio in cranidia reveals isometric growth during ontogeny for both morphotypes. The transition from the meraspid to holaspid ontogenetic period has been established through recognition of the successive development of the number of thoracic segments in articulated late meraspides. Throughout its life cycle, S. inflata went through 11 meraspid degrees and at least 17 holaspid growth stages. Inferred moult ensembles and exuviae reveal the successive opening of cephalic sutures and the function of the rostral plate during exuviation. As in other ellipsocephalid trilobites in which enrolment is known, the pygidium and two or three thoracic segments of S. inflata are concealed beneath the cephalon (spiral enrolment) during complete enrolment.", "keyphrases": ["sexual dimorphism", "ptychopariid trilobite strenuaeva", "moulting"]}
{"id": "10.4072/rbp.2005.1.03", "title": "New information on Brasilodon and Brasilitherium (Cynodontia, Probainognathia) from the Late Triassic, southern Brazil", "abstract": "\u0096 New discoveries of articulated skulls and lower jaws of Brasilodon and Brasilitherium from the Late Triassic of Brazil provide additional information on these small cynodonts, allowing us to establish the family Brasilodontidae nov. The basicranium, lateral wall of the braincase, primary and secondary palates and the quadrate of Brasilitherium are described, as well as the basicranium, primary palate and lower jaw of Brasilodon. Brasilitherium exhibits more derived characters than Brasilodon in the periotic, the promontorium, and the articular process of the dentary. Brasilodon is more derived in the lower dentition, the mode of tooth replacement, and the vascular features in the \u0093stapedial recess\u0094. Both genera have interpterygoid vacuities that are considered here as possibly derived or reversed characters of the mammalian primary palate. The new phylogenetic analysis presented here corroborates the position of both genera as sister-group of mammals as previously proposed.", "keyphrases": ["brasilodon", "late triassic", "brazil"]}
{"id": "paleo.000249", "title": "SPIERS and VAXML; A software toolkit for tomographic visualisation and a format for virtual specimen interchange", "abstract": "Virtual palaeontology', the study of fossils through the medium of digital models, is an increasingly important palaeontological technique. The vast majority of such work is tomographic, based around serial-slice datasets generated either physically or via scanning technologies. There are, however, no general-purpose software packages for tomographic reconstruction that are freely available and tuned to the needs of palaeontological data. In addition to its value in the primary study of specimens, virtual palaeontology has the potential to become a powerful medium for online data-dissemination, greatly increasing the degree to which palaeontologists are able to inspect each other's data. The absence of a standardised data-format for these datasets, however, has been a primary factor impeding such data exchange. We describe here solutions to both problems. The SPIERS software suite is a complete, free, multi-platform and fully documented software toolkit for the reconstruction of any tomographic data into threedimensional models. While capable of rapid reconstruction, it is especially well suited to the production of carefully prepared models from difficult data. We argue that virtualspecimen dissemination should take the form of triangle-mesh datasets, which can be generated from a maximally broad range of data sources. We introduce here the VAXML data format for such datasets, a candidate for a standard dissemination format for virtual specimens, both palaeontological and biological. The SPIERS suite includes a package capable of both visualising and exporting VAXML files, designed to support the viewing of complex datasets on relatively low-powered systems.", "keyphrases": ["software toolkit", "tomographic dataset", "virtual fossil"]}
{"id": "10.3853/j.0067-1975.62.2010.1537", "title": "A new avian species with tubercle-bearing cervical vertebrae from the Middle Eocene of Messel (Germany). In Proceedings of the VII International Meeting of the Society of Avian Paleontology and Evolution, ed. W.E. Boles and T.H. Worthy", "abstract": "A new avian species, Perplexicervix microcephalon n.gen. and n.sp., is described from the Middle Eocene of Messel in Germany. It is most unusual in that the cervical vertebrae of five of the six known specimens bear numerous bony tubercles. Such tubercles were also reported from another avian fossil from the Messel deposits, which is a representative of the extinct taxon Idiornithidae. Although the osteology of P. microcephalon is not known well enough for a reliable phylogenetic assignment, the new species clearly does not belong to the Idiornithidae. Compared to extant birds, it agrees with Anhimidae and Cathartidae in some osteological features. The origin of the vertebral tubercles remains mysterious. The fact that these structures are now known from two unrelated avian taxa supports previous assumptions, that they represent a pathologic condition. Not in line with this assumption, however, is their occurrence in all specimens referred to P. microcephalon, in which cervical vertebrae are preserved.", "keyphrases": ["new avian specie", "cervical vertebrae", "middle eocene"]}
{"id": "10.3389/fevo.2021.622412", "title": "Testing Equid Body Mass Estimate Equations on Modern Zebras\u2014With Implications to Understanding the Relationship of Body Size, Diet, and Habitats of Equus in the Pleistocene of Europe", "abstract": "The monodactyl horses of the genus Equus originated in North America during the Pliocene, and from the beginning of the Pleistocene, they have been an essential part of the large ungulate communities of Europe, North America and Africa. Understanding how body size of Equus species evolved and varied in relation to changes in environments and diet thus forms an important part of understanding the dynamics of ungulate body size variation in relation to Pleistocene paleoenvironmental changes. Here we test previously published body mass estimation equations for the family Equidae by investigating how accurately different skeletal and dental measurements estimate the mean body mass (and body mass range) reported for extant Grevy's zebra (Equus grevyi) and Burchell's zebra (Equus quagga). Based on these tests and information on how frequently skeletal elements occur in the fossil record, we construct a hierarchy of best practices for the selection of body mass estimation equations in Equus. As a case study, we explore body size variation in Pleistocene European Equus paleopopulations in relation to diet and vegetation structure in their paleoenvironments. We show a relationship between diet and body size in Equus: very large-sized species tend to have more browse-dominated diets than small and medium-sized species, and paleovegetation proxies indicate on average more open and grass-rich paleoenvironments for small-sized, grazing species of Equus. When more than one species of Equus co-occur sympatrically, the larger species tend to be less abundant and have more browse-dominated diets than the smaller species. We suggest that body size variation in Pleistocene Equus was driven by a combined effect of resource quality and availability, partitioning of habitats and resources between species, and the effect of environmental openness and group size on the body size of individuals.", "keyphrases": ["body size", "equus", "pleistocene"]}
{"id": "paleo.001628", "title": "Morphofunctional Analysis of the Quadrate of Spinosauridae (Dinosauria: Theropoda) and the Presence of Spinosaurus and a Second Spinosaurine Taxon in the Cenomanian of North Africa.", "abstract": "Six quadrate bones, of which two almost certainly come from the Kem Kem beds (Cenomanian, Upper Cretaceous) of south-eastern Morocco, are determined to be from juvenile and adult individuals of Spinosaurinae based on phylogenetic, geometric morphometric, and phylogenetic morphometric analyses. Their morphology indicates two morphotypes evidencing the presence of two spinosaurine taxa ascribed to Spinosaurus aegyptiacus and? Sigilmassasaurus brevicollis in the Cenomanian of North Africa, casting doubt on the accuracy of some recent skeletal reconstructions which may be based on elements from several distinct species. Morphofunctional analysis of the mandibular articulation of the quadrate has shown that the jaw mechanics was peculiar in Spinosauridae. In mature spinosaurids, the posterior parts of the two mandibular rami displaced laterally when the jaw was depressed due to a lateromedially oriented intercondylar sulcus of the quadrate. Such lateral movement of the mandibular ramus was possible due to a movable mandibular symphysis in spinosaurids, allowing the pharynx to be widened. Similar jaw mechanics also occur in some pterosaurs and living pelecanids which are both adapted to capture and swallow large prey items. Spinosauridae, which were engaged, at least partially, in a piscivorous lifestyle, were able to consume large fish and may have occasionally fed on other prey such as pterosaurs and juvenile dinosaurs.", "keyphrases": ["spinosauridae", "cenomanian", "jaw mechanic", "morphofunctional analysis"]}
{"id": "paleo.002988", "title": "The importance of sampling standardization for comparisons of insect herbivory in deep time: a case study from the late Palaeozoic", "abstract": "Sampling standardization has not been fully addressed for the study of insect herbivory in the fossil record. The effects of sampling within a single locality were explored almost a decade ago, but the importance of sampling standardization for comparisons of herbivory across space and time has not yet been evaluated. Here, we present a case study from the Permian in which we evaluate the impact of sampling standardization on comparisons of insect herbivory from two localities that are similar in age and floral composition. Comparisons of insect damage type (DT) diversity change dramatically when the number of leaves examined is standardized by surface area. This finding suggests that surface area should always be taken into account for comparisons of DT diversity. In addition, the three most common metrics of herbivory\u2014DT diversity, proportion of leaves herbivorized and proportion of leaf surface area herbivorized\u2014are inherently decoupled from each other. The decoupling of the diversity and intensity of insect herbivory necessitates a reinterpretation of published data because they had been conflated in previous studies. Future studies should examine the divergent ecological factors that underlie these metrics. We conclude with suggestions to guide the sampling and analysis of herbivorized leaves in the fossil record.", "keyphrases": ["standardization", "insect herbivory", "case study"]}
{"id": "10.1111/j.1365-2451.2009.00714.x", "title": "Digital imaging and public engagement in palaeontology", "abstract": "Public engagement and the promotion of science to a wider non\u2010academic audience form an integral role of the professional scientist in the twenty\u2010first century. The high level of public interest in palaeontology means that the Earth's prehistoric past can provide an important medium through which to communicate information concerning contemporary scientific issues. Here we explain how modern computer techniques can be used to enhance public understanding of complex palaeontological issues.", "keyphrases": ["public engagement", "palaeontology", "science"]}
{"id": "10.1126/science.aap8369", "title": "The earliest modern humans outside Africa", "abstract": "Earliest modern humans out of Africa Recent paleoanthropological studies have suggested that modern humans migrated from Africa as early as the beginning of the Late Pleistocene, 120,000 years ago. Hershkovitz et al. now suggest that early modern humans were already present outside of Africa more than 55,000 years earlier (see the Perspective by Stringer and Galway-Witham). During excavations of sediments at Mount Carmel, Israel, they found a fossil of a mouth part, a left hemimaxilla, with almost complete dentition. The sediments contain a series of well-defined hearths and a rich stone-based industry, as well as abundant animal remains. Analysis of the human remains, and dating of the site and the fossil itself, indicate a likely age of at least 177,000 years for the fossil\u2014making it the oldest member of the Homo sapiens clade found outside Africa. Science, this issue p. 456; see also p. 389 Fossilized mouthparts indicate the presence of Homo sapiens in the Levant 160,000 years ago. To date, the earliest modern human fossils found outside of Africa are dated to around 90,000 to 120,000 years ago at the Levantine sites of Skhul and Qafzeh. A maxilla and associated dentition recently discovered at Misliya Cave, Israel, was dated to 177,000 to 194,000 years ago, suggesting that members of the Homo sapiens clade left Africa earlier than previously thought. This finding changes our view on modern human dispersal and is consistent with recent genetic studies, which have posited the possibility of an earlier dispersal of Homo sapiens around 220,000 years ago. The Misliya maxilla is associated with full-fledged Levallois technology in the Levant, suggesting that the emergence of this technology is linked to the appearance of Homo sapiens in the region, as has been documented in Africa.", "keyphrases": ["africa", "early modern human", "levant"]}
{"id": "10.1098/rsbl.2008.0491", "title": "Palaeogenomics of pterosaurs and the evolution of small genome size in flying vertebrates", "abstract": "The two living groups of flying vertebrates, birds and bats, both have constricted genome sizes compared with their close relatives. But nothing is known about the genomic characteristics of pterosaurs, which took to the air over 70\u200aMyr before birds and were the first group of vertebrates to evolve powered flight. Here, we estimate genome size for four species of pterosaurs and seven species of basal archosauromorphs using a Bayesian comparative approach. Our results suggest that small genomes commonly associated with flight in bats and birds also evolved in pterosaurs, and that the rate of genome-size evolution is proportional to genome size within amniotes, with the fastest rates occurring in lineages with the largest genomes. We examine the role that drift may have played in the evolution of genome size within tetrapods by testing for correlated evolution between genome size and body size, but find no support for this hypothesis. By contrast, we find evidence suggesting that a combination of adaptation and phylogenetic inertia best explains the correlated evolution of flight and genome-size contraction. These results suggest that small genome/cell size evolved prior to or concurrently with flight in pterosaurs. We predict that, similar to the pattern seen in theropod dinosaurs, genome-size contraction preceded flight in pterosaurs and bats.", "keyphrases": ["pterosaur", "genome size", "vertebrate"]}
{"id": "paleo.004944", "title": "Recalibration of the insect evolutionary time scale using Monte San Giorgio fossils suggests survival of key lineages through the End-Permian Extinction", "abstract": "Insects are a highly diverse group of organisms and constitute more than half of all known animal species. They have evolved an extraordinary range of traits, from flight and complete metamorphosis to complex polyphenisms and advanced eusociality. Although the rich insect fossil record has helped to chart the appearance of many phenotypic innovations, data are scarce for a number of key periods. One such period is that following the End-Permian Extinction, recognized as the most catastrophic of all extinction events. We recently discovered several 240-million-year-old insect fossils in the Mount San Giorgio Lagerst\u00e4tte (Switzerland\u2013Italy) that are remarkable for their state of preservation (including internal organs and soft tissues), and because they extend the records of their respective taxa by up to 200 million years. By using these fossils as calibrations in a phylogenomic dating analysis, we present a revised time scale for insect evolution. Our date estimates for several major lineages, including the hyperdiverse crown groups of Lepidoptera, Hemiptera: Heteroptera and Diptera, are substantially older than their currently accepted post-Permian origins. We found that major evolutionary innovations, including flight and metamorphosis, appeared considerably earlier than previously thought. These results have numerous implications for understanding the evolution of insects and their resilience in the face of extreme events such as the End-Permian Extinction.", "keyphrases": ["insect", "time scale", "end-permian extinction"]}
{"id": "paleo.005475", "title": "Bryozoans as taphonomic engineers, with examples from the Upper Ordovician (Katian) of Midwestern North America", "abstract": "A combination of encrusting calcitic bryozoans and early seafloor dissolution of aragonitic shells recorded in the Cincinnatian Series of the upper Midwest of North America allowed the preservation of abundant moulds of mollusc fossils bioimmured beneath the attachment surfaces of the bryozoans. We here call this preservational process 'bryoimmuration', defined as a bryozoan-mediated subset of bioimmuration. The bryozoans moulded very fine details of the mollusc shells, usually with more accuracy than inorganic sediment moulds. Most of the bryozoans are heterotrypid trepostomes with robust low-Mg calcite skeletons. The molluscs are primarily bivalves, gastropods, nautiloids and monoplacophorans with their originally aragonitic shells now dissolved. Many of the encrusting bryozoans are so thin and broad that they give the illusion of calcitic mollusc shells clinging to the moulds. Some molluscs in the Cincinnatian, especially monoplacophorans and epifaunal bivalves, would be poorly known if they had not been bryoimmured. Unlike internal and external moulds in sediment, bryoimmured fossils could be transported and thus record aragonitic faunas in taphonomic assemblages (e.g. storm beds) in which they would otherwise be rare or absent. In addition, bryoimmurations of aragonitic shells often reveal the ecological succession of encrustation on the shells by exposing the earliest encrusters and borings that were later overgrown. Bryoimmuration was common during the Late Ordovician because the calcite sea at the time quickly dissolved aragonitic shells on the seafloor before final burial, and large calcitic bryozoans very commonly used molluscs as substrates. Bryoimmuration is an important taphonomic process for preserving aragonitic faunas, and it reveals critical information about sclerobiont palaeoecology. Several Cincinnatian mollusc holotypes are bryoimmured specimens. Bryozoans involved in bryoimmuration enhance the preservation of aragonitic fauna and thus act as taphonomic engineers.", "keyphrases": ["taphonomic engineer", "bryoimmuration", "bryozoans"]}
{"id": "10.1002/spp2.1277", "title": "Systematics, preservation and biogeography of radiodonts from the southern Great Basin, USA, during the upper Dyeran (Cambrian Series 2, Stage 4)", "abstract": "Anomalocaris, the most well\u2010known genus of the diverse stem euarthropod group Radiodonta, was first reported over 100 years ago from the Burgess Shale (Canada). This large Cambrian apex predator was later treated as occurring in the southern Great Basin (California and Nevada, USA). We re\u2010evaluate the systematic affinities of previously described material from the Pioche Formation, Nevada, and the Latham Shale, California, and describe the first radiodonts from the Pyramid Shale Member, Carrara Formation, California. Latham Shale (Cambrian Series 2, Stage 4, upper Dyeran) specimens previously assigned to Anomalocaris are reinterpreted as Ramskoeldia consimilis?, an amplectobeluid previously known only from the Chengjiang biota (Cambrian Series 2, Stage 3). Younger material from the Pioche and Carrara Formations (Series 2, Stage 4) is described as a new Anomalocaris species, A. magnabasis. This new species sheds light on the two\u2010part structure of Anomalocaris ventral endites, a potentially important character for distinguishing species, and reveals a sequence of five disarticulation stages for frontal appendages. The oldest Hurdia from Laurentia is also reported from the Pioche Formation (Cambrian Series 2, Stage 4). A changeover in taxonomic composition of the Radiodonta in the southern Great Basin is recognized: Anomalocaris replaces Ramskoeldia in the upper Dyeran, but it is not associated with a replacement of local olenelloid trilobites or seen in radiodonts elsewhere in Laurentia. These new data, combined with a summary of known radiodont occurrences, suggest that Anomalocaris species did not have large geographical distributions, when compared with other radiodonts such as Hurdia and Caryosyntrips.", "keyphrases": ["radiodont", "southern great basin", "cambrian series"]}
{"id": "paleo.005765", "title": "Seven rules for simulations in paleobiology", "abstract": "Abstract. Simulations are playing an increasingly important role in paleobiology. When designing a simulation study, many decisions have to be made and common challenges will be encountered along the way. Here, we outline seven rules for executing a good simulation study. We cover topics including the choice of study question, the empirical data used as a basis for the study, statistical and methodological concerns, how to validate the study, and how to ensure it can be reproduced and extended by others. We hope that these rules and the accompanying examples will guide paleobiologists when using simulation tools to address fundamental questions about the evolution of life.", "keyphrases": ["rule", "simulation", "paleobiology"]}
{"id": "10.1130/G19800.1", "title": "Significant Southern Ocean warming event in the late middle Eocene", "abstract": "A prominent middle Eocene warming event is identified in Southern Ocean deep-sea cores, indicating that long-term cooling through the middle and late Eocene was not monotonic. At sites on Maud Rise and the Kerguelen Plateau, a distinct negative shift in \u03b4 1 8 O values (\u223c1.0\u2030) is observed ca. 41.5 Ma. This excursion is interpreted as primarily a temperature signal, with a transient warming of 4 \u00b0C over 600 k.y. affecting both surface and middle-bathyal deep waters in the Indian-Atlantic region of the Southern Ocean. This isotopic event is designated as the middle Eocene climatic optimum, and is interpreted to represent a significant climatic reversal in the midst of middle to late Eocene deep-sea cooling. The lack of a significant negative carbon isotope excursion, as observed during the Paleocene-Eocene thermal maximum, and the gradual rate of high-latitude warming suggest that this event was not triggered by methane hydrate dissociation. Rather, a transient rise in pCO 2 levels is suspected, possibly as a result of metamorphic decarbonation in the Himalayan orogen or increased ridge/arc volcanism during the late middle Eocene.", "keyphrases": ["warming event", "middle eocene", "meco"]}
{"id": "paleo.005050", "title": "Phylogeny and escalation in Mellopegma and other Cambrian molluscs", "abstract": "Mellopegma Runnegar and Jell is a widespread Cambrian stenothecid helcionellid mollusc that may represent the ancestral state of rostroconchs. New fossils provide details about the morphology and evolution of this genus.\nMany specimens show healed wounds, indicating Mellopegma experienced frequent predation. Common scars near the sub-apical aperture indicate this area was a favoured target. Predation may have led to the formation of the strengthening zygion in this region of the possible descendent Eurekapegma MacKinnon. Mellopegma exhibits many anti-predator traits, and preliminary analyses herein show: 1) Mellopegma became better defensed through time via aperture narrowing; and 2) stenothecids show an increase in proportion of damaged shells from early to middle Cambrian deposits. This evidence is consistent with an early arms race between predators and molluscan prey.\nSpecimens from Siberia reveal that calcitic semi-nacre has a deeper history in the Mollusca than previously thought, consistent with the hypothesis that this shell microstructure occurs in both molluscs and brachiopods due to homology in the organic framework for shell formation. The shell of Mellopegma contained pores and the commonality of this trait among early molluscs suggests a porous shell may be primitive in Mollusca. The protoconch/teleoconch boundary is distinct in many specimens and indicates the fossils are of adult shells, and Mellopegma was lecithotrophic. One specimen of Mellopegma preserves the periostracum.\nMellopegma schizocheras sp. nov. is described from the middle Cambrian of Australia. Anabarella simesi MacKinnon is transferred to Mellopegma. Ribeiria junior Runnegar is removed from Rostroconchia and transferred to the new genus Acanthotheca.", "keyphrases": ["mellopegma", "mollusc", "rostroconch"]}
{"id": "paleo.009072", "title": "Biomineralization by particle attachment in early animals", "abstract": "Significance The mechanisms by which organisms form mineralized skeletons have been a major research focus for the last 50 y and remain so today. Among the most surprising discoveries is the recent observation that different animals use the same mechanisms, and precisely the same amorphous precursors, to form biomineralized structures as diverse as coral skeletons, molluscan shells, and sea urchin spines. In living animals, skeletal biomineralization from amorphous precursors correlates with a distinctive nanoparticulate texture that can be preserved in fossils, enabling us to probe mechanisms of skeletal formation in early animals. We document nanoparticulate texture in some of the oldest known carbonate skeletons, which strongly suggests that skeletons formed from amorphous precursors throughout the recorded history of animals. Crystallization by particle attachment (CPA) of amorphous precursors has been demonstrated in modern biomineralized skeletons across a broad phylogenetic range of animals. Precisely the same precursors, hydrated (ACC-H2O) and anhydrous calcium carbonate (ACC), have been observed spectromicroscopically in echinoderms, mollusks, and cnidarians, phyla drawn from the 3 major clades of eumetazoans. Scanning electron microscopy (SEM) here also shows evidence of CPA in tunicate chordates. This is surprising, as species in these clades have no common ancestor that formed a mineralized skeleton and appear to have evolved carbonate biomineralization independently millions of years after their late Neoproterozoic divergence. Here we correlate the occurrence of CPA from ACC precursor particles with nanoparticulate fabric and then use the latter to investigate the antiquity of the former. SEM images of early biominerals from Ediacaran and Cambrian shelly fossils show that these early calcifiers used attachment of ACC particles to form their biominerals. The convergent evolution of biomineral CPA may have been dictated by the same thermodynamics and kinetics as we observe today.", "keyphrases": ["particle attachment", "early animal", "crystallization", "calcium carbonate", "biomineralization"]}
{"id": "paleo.012611", "title": "Phytoliths Analysis for the Discrimination of Foxtail Millet (Setaria italica) and Common Millet (Panicum miliaceum)", "abstract": "Foxtail millet (Setaria italica) and Common millet (Panicum miliaceum) are the oldest domesticated dry farming crops in Eurasia. Identifying these two millets in the archaeobotanical remains are still problematic, especially because the millet grains preserve only when charred. Phytoliths analysis provides a viable method for identifying this important crop. However, to date, the identification of millet phytoliths has been questionable, because very little study has been done on their morphometry and taxonomy. Particularly, no clear diagnostic feature has been used to distinguish between Foxtail millet and Common millet. Here we examined the anatomy and silicon structure patterns in the glumes, lemmas, and paleas from the inflorescence bracts in 27 modern plants of Foxtail millet, Common millet, and closely related grasses, using light microscopy with phase-contrast and microscopic interferometer. Our research shows that five key diagnostic characteristics in phytolith morphology can be used to distinguish Foxtail millet from Common millet based on the presence of cross-shaped type, regularly arranged papillae, \u03a9-undulated type, endings structures of epidermal long cell, and surface ridgy line sculpture in the former species. We have established identification criteria that, when used together, give the only reliable way of distinguishing between Foxtail millet and Common millet species based on their phytoliths characteristics, thus making a methodological contribution to phytolith research. Our findings also have important implications in the fields of plant taxonomy, agricultural archaeology, and the culture history of ancient civilizations.", "keyphrases": ["foxtail millet", "panicum miliaceum", "palea", "grass", "phytolith"]}
{"id": "10.1017/jpa.2020.65", "title": "Intravital damage to the body of Dickinsonia (Metazoa of the late Ediacaran)", "abstract": "Abstract. Several specimens of Dickinsonia cf. D. menneri, originating from a single burial event at the Lyamtsa locality of the late Ediacaran (Vendian) in the southeastern White Sea area, Russia, represent deviations from normal morphology: a reduction in the total length of the body; the loss of portions of the body; various deformations of the transverse elements, called isomers; and splitting of the longitudinal axis with the formation of two posterior ends. It is assumed that these deformations were formed as a result of non-lethal damage, which occurred long before the burial event, and the response of Dickinsonia to them. The progress of the regeneration process at the damaged areas, and especially its deviations, indicates that the growth zone was located at the posterior end of the Dickinsonia body. The cause of non-lethal damage to Dickinsonia could not be established, but the local distribution of deformed specimens preserved in the same burial event alongside cyanobacterial colonies, and the presence of weak deformations, expressed only in shortening of the length of some isomers, lead to the conclusion that damage resulted from short episodes of physicochemical impact, rather than occasional attacks by a hypothetical macrophage.", "keyphrases": ["damage", "dickinsonia", "intravital damage"]}
{"id": "paleo.012436", "title": "Cofactors are Remnants of Life\u2019s Origin and Early Evolution", "abstract": "The RNA World is one of the most widely accepted hypotheses explaining the origin of the genetic system used by all organisms today. It proposes that the tripartite system of DNA, RNA, and proteins was preceded by one consisting solely of RNA, which both stored genetic information and performed the molecular functions encoded by that genetic information. Current research into a potential RNA World revolves around the catalytic properties of RNA-based enzymes, or ribozymes. Well before the discovery of ribozymes, Harold White proposed that evidence for a precursor RNA world could be found within modern proteins in the form of coenzymes, the majority of which contain nucleobases or nucleoside moieties, such as Coenzyme A and S-adenosyl methionine, or are themselves nucleotides, such as ATP and NADH (a dinucleotide). These coenzymes, White suggested, had been the catalytic active sites of ancient ribozymes, which transitioned to their current forms after the surrounding ribozyme scaffolds had been replaced by protein apoenzymes during the evolution of translation. Since its proposal four decades ago, this groundbreaking hypothesis has garnered support from several different research disciplines and motivated similar hypotheses about other classes of cofactors, most notably iron-sulfur cluster cofactors as remnants of the geochemical setting of the origin of life. Evidence from prebiotic geochemistry, ribozyme biochemistry, and evolutionary biology, increasingly supports these hypotheses. Certain coenzymes and cofactors may bridge modern biology with the past and can thus provide insights into the elusive and poorly-recorded period of the origin and early evolution of life.", "keyphrases": ["remnant", "early evolution", "nadh", "cofactor"]}
{"id": "paleo.009355", "title": "Recovery of cell nuclei from 15,000 years old mammoth tissues and its injection into mouse enucleated matured oocytes", "abstract": "Here, we report the recovery of cell nuclei from 14,000\u201315,000 years old mammoth tissues and the injection of those nuclei into mouse enucleated matured oocytes by somatic cell nuclear transfer (SCNT). From both skin and muscle tissues, cell nucleus-like structures were successfully recovered. Those nuclei were then injected into enucleated oocytes and more than half of the oocytes were able to survive. Injected nuclei were not taken apart and remained its nuclear structure. Those oocytes did not show disappearance of nuclear membrane or premature chromosome condensation (PCC) at 1 hour after injection and did not form pronuclear-like structures at 7 hours after injection. As half of the oocytes injected with nuclei derived from frozen-thawed mouse bone marrow cells were able to form pronuclear-like structures, it might be possible to promote the cell cycle of nuclei from ancient animal tissues by suitable pre-treatment in SCNT. This is the first report of SCNT with nuclei derived from mammoth tissues.", "keyphrases": ["mammoth tissue", "oocyte", "recovery"]}
{"id": "paleo.001384", "title": "Earliest filter-feeding pterosaur from the Jurassic of China and ecological evolution of Pterodactyloidea", "abstract": "Pterosaurs were a unique clade of flying reptiles that were contemporaries of dinosaurs in Mesozoic ecosystems. The Pterodactyloidea as the most species-diverse group of pterosaurs dominated the sky during Cretaceous time, but earlier phases of their evolution remain poorly known. Here, we describe a 160\u2009Ma filter-feeding pterosaur from western Liaoning, China, representing the geologically oldest record of the Ctenochasmatidae, a group of exclusive filter feeders characterized by an elongated snout and numerous fine teeth. The new pterosaur took the lead of a major ecological transition in pterosaur evolution from fish-catching to filter-feeding adaptation, prior to the Tithonian (145\u2013152\u2009Ma) diversification of the Ctenochasmatidae. Our research shows that the rise of ctenochasmatid pterosaurs was followed by the burst of eco-morphological divergence of other pterodactyloid clades, which involved a wide range of feeding adaptations that considerably altered the terrestrial ecosystems of the Cretaceous world.", "keyphrases": ["filter-feeding pterosaur", "pterosaur", "pterodactyloidea"]}
{"id": "paleo.010913", "title": "Environmental changes define ecological limits to species richness and reveal the mode of macroevolutionary competition", "abstract": "Abstract Co\u2010dependent geological and climatic changes obscure how species interact in deep time. The interplay between these environmental factors makes it hard to discern whether ecological competition exerts an upper limit on species richness. Here, using the exceptional fossil record of Cenozoic Era macroperforate planktonic foraminifera, we assess the evidence for alternative modes of macroevolutionary competition. Our models support an environmentally dependent macroevolutionary form of contest competition that yields finite upper bounds on species richness. Models of biotic competition assuming unchanging environmental conditions were overwhelmingly rejected. In the best\u2010supported model, temperature affects the per\u2010lineage diversification rate, while both temperature and an environmental driver of sediment accumulation defines the upper limit. The support for contest competition implies that incumbency constrains species richness by restricting niche availability, and that the number of macroevolutionary niches varies as a function of environmental changes.", "keyphrases": ["competition", "environmental change", "speciation"]}
{"id": "paleo.011060", "title": "The \u201cBear\u201d Essentials: Actualistic Research on Ursus arctos arctos in the Spanish Pyrenees and Its Implications for Paleontology and Archaeology", "abstract": "Neotaphonomic studies of large carnivores are used to create models in order to explain the formation of terrestrial vertebrate fossil faunas. The research reported here adds to the growing body of knowledge on the taphonomic consequences of large carnivore behavior in temperate habitats and has important implications for paleontology and archaeology. Using photo- and videotrap data, we were able to describe the consumption of 17 ungulate carcasses by wild brown bears (Ursus arctos arctos) ranging the Spanish Pyrenees. Further, we analyzed the taphonomic impact of these feeding bouts on the bones recovered from those carcasses. The general sequence of consumption that we charted starts with separation of a carcass\u2019s trunk; viscera are generally eaten first, followed by musculature of the humerus and femur. Long limb bones are not broken open for marrow extraction. Bears did not transport carcasses or carcass parts from points of feeding and did not disperse bones appreciably (if at all) from their anatomical positions. The general pattern of damage that resulted from bear feeding includes fracturing, peeling, crenulation, tooth pitting and scoring of axial and girdle elements and furrowing of the upper long limb bones. As predicted from observational data, the taphonomic consequences of bear feeding resemble those of other non-durophagus carnivores, such as felids, and are distinct from those of durophagus carnivores, such as hyenids. Our results have paleontological and archaeological relevance. Specifically, they may prove useful in building analogical models for interpreting the formation of fossil faunas for which bears are suspected bone accumulators and/or modifiers. More generally, our comparative statistical analyses draw precise quantitative distinctions between bone damage patterns imparted respectively by durophagus (modelled here primarily by spotted hyenas [Crocuta crocuta] and wolves [Canis lupus]) and non-durophagus (modelled here by brown bears and lions [Panthera leo]) carnivorans.", "keyphrases": ["bear", "spanish pyrenees", "archaeology"]}
{"id": "paleo.007662", "title": "Small carbonaceous fossils (SCFs) from the Terreneuvian (lower Cambrian) of Baltica", "abstract": "We describe a new assemblage of small carbonaceous fossils (SCFs) from diagenetically minimally altered clays and siltstones of Terreneuvian age from the Lontova and Voosi formations of Estonia, Lithuania and Russia. This is the first detailed account of an SCF assemblage from the Terreneuvian and includes a number of previously undocumented Cambrian organisms. Recognizably bilaterian\u2010derived SCFs include abundant protoconodonts (total\u2010group Chaetognatha), and distinctive cuticular spines of scalidophoran worms. Alongside these metazoan remains are a range of protistan\u2010grade fossils, including Retiranus balticus gen. et sp. nov., a distinctive funnel\u2010shaped or sheet\u2010like problematicum characterized by terminal or marginal vesicles, and Lontohystrichosphaera grandis gen. et sp. nov., a large (100\u2013550 \u03bcm) ornamented vesicular microfossil. Together these data offer a fundamentally enriched view of Terreneuvian life in the epicratonic seas of Baltica, from an episode where records of non\u2010biomineralized life are currently sparse. Even so, the recovered assemblages contain a lower diversity of metazoans than SCF biotas from younger (Stage 4) Baltic successions that represent broadly equivalent environments, echoing the diversification signal recorded in the coeval shelly and trace\u2010fossil records. Close comparison to the biostratigraphical signal from Fortunian small shelly fossils supports a late Fortunian age for most of the Lontova/Voosi succession, rather than a younger (wholly Stage 2) range.", "keyphrases": ["terreneuvian", "baltica", "small carbonaceous fossil"]}
{"id": "10.1017/s0094837300019849", "title": "Septal complexity in ammonoid cephalopods increased mechanical risk and limited depth", "abstract": "The evolution of septal complexity in fossil ammonoids has been widely regarded as an adaptive response to mechanical stresses imposed on the shell by hydrostatic pressure. Thus, septal (and hence sutural) complexity has been used as a proxy for depth: for a given amount of septal material greater complexity permitted greater habitat depth. We show that the ultimate septum is the weakest part of the chambered shell. Additionally, finite element stress analyses of a variety of septal geometries exposed to pressure stresses show that any departure from a hemispherical shape actually yields higher, not lower, stresses in the septal surface. Further analyses show, however, that an increase in complexity is consistent with selective pressures of predation and buoyancy control. Regardless of the mechanisms that drove the evolution of septal complexity, our results clearly reject the assertion that complexly sutured ammonoids were able to inhabit deeper water than did ammonoids with simpler septa. We suggest that while more complexly sutured ammonoids were limited to shallower habitats, the accompanying more complex septal topograhies enhanced buoyancy regulation (chamber emptying and refilling), through increased surface tension effects.", "keyphrases": ["ammonoid", "depth", "septal complexity"]}
{"id": "paleo.002576", "title": "Homology and Architecture of the Caudal Basket of Pachycephalosauria (Dinosauria: Ornithischia): The First Occurrence of Myorhabdoi in Tetrapoda", "abstract": "Background Associated postcranial skeletons of pachycephalosaurids, most notably those of Stegoceras and Homalocephale, reveal enigmatic osseous structures not present in other tetrapod clades. The homology and functional significance of these structures have remained elusive as they were originally interpreted to be abdominal ribs or gastralia, and more recently have been interpreted as de novo structures in the tail. Principal Findings Analysis of these structures in nearly all pachycephalosaurid skeletons has facilitated a complete description of their architecture, and the establishment of patterns consistent with those of myorhabdoid ossifications \u2014 ossifications of the myoseptal tendons associated with myomeres. The presence and structure of myorhabdoid ossifications are well established for teleost fish, but this marks their first recognition within Tetrapoda. These elements are both structurally and histologically distinct from the deep, paraxial ossified tendon bundles of other ornithischian clades, although they may have performed a similar function in the stiffening of the tail. Conclusions/Significance These myorhabdoi are not de novo structures, but are instead ossifications (and therefore more amenable to fossilization) of the normally unossified plesiomorphic caudal myosepta of vertebrates. The ubiquitous ossification of these structures in pachycephalosaurids (all specimens preserving the tail also exhibit myorhabdoid ossifications) suggests it is a likely synapomorphic condition for Pachycephalosauria.", "keyphrases": ["pachycephalosauria", "myorhabdoi", "tetrapoda"]}
{"id": "10.1017/S0263593300010452", "title": "Pelagic trilobites as an example of deducing the life habits of extinct arthropods", "abstract": "ABSTRACT This paper reviews the methods which have been used to deduce the life habits of trilobites. The most reliable conclusions are those that satisfy three independent criteria of evidence: (1) functional morphology of the exoskeleton; (2) analogy with living arthropods; and (3) geological evidence, as from facies relationships, or palaeogeography. Pelagic trilobites are one of the better examples for life habit reconstruction. The Ordovician trilobites that were most probably pelagic are those with hypertrophied eyes\u2014Telephinidae, Opipeuteridae, Bohemillidae and Cyclopygidae\u2014which satisfy the threefold requirements for evidence. Opipeuter, Carolinites (and other telephinids) were probably epipelagic, whereas cyclopygids and Bohemilla were likely to have been mesopelagic, living in exterior sites around the perimeter of Gondwana in the earlier Ordovician. These pelagics divide into two morphological groups: poorly streamlined, sluggish species somewhat like the living hyperiid Parathemisto, and well-streamlined species which are larger, and are considered to have been fast and active swimmers, with predatory habits. The streamlining of this group has been demonstrated by experiment. Other trilobites may also have been pelagic, but the evidence is less complete: Irvingella and its homeomorphs, and Remopleurides. Most Olenidae, however, which have been supposed to have been pelagic, were benthic forms inhabiting a specialised environment low in oxygen and possibly below the thermocline; only the leptoplastines may have been pelagic. It is also shown that there are cases where ventral terrace ridges did not function to grip sediment during filter feeding. This applies not only to pelagic trilobites, but also to benthic ones in which the width and disposition of the doublure renders engagement with the sediment unlikely.", "keyphrases": ["life habit", "arthropod", "pelagic trilobite"]}
{"id": "10.1080/02724634.2011.550360", "title": "Tapiridae (Perissodactyla, Mammalia) of the Swiss Molasse Basin During the Oligocene\u2014Miocene Transition", "abstract": "Abstract \n The Tapiridae of the Swiss Molasse Basin from the late Oligocene to the early Miocene are reviewed. Fossil remains that have not previously been described are identified, old descriptions and identifications from previous works are reassessed, and specimens from Switzerland and France are compared, specifically Protapirus bavaricus from Ebnat-Kappel (MP28) and R\u00fcfi bei Sch\u00fcnis (MP29), Protapirus aginensis from La Milloque (France, MP29), Protapirus douvillei from Buchberg 6 (MN4), Paratapirus helvetius from Haslen (Switzerland, MP28-30), Paratapirus intermedius from Saulcet (France, MN1), H\u00f6hronen (MN1), and Br\u00fcttelen 1 (MN3a), and Eotapirus broennimanni from Wischberg (MN1) and Benken (MN3-4?). These new data enable emended specific diagnoses for Protapirus bavaricus, P. aginensis, and P. douvillei. A late Oligocene (MP28-30) age for the locality of Haslen\u2014the neotype locality of Paratapirus helvetius\u2014is also attributed, based upon the literature and personal observations. Furthermore, a new and precise biostratigraphic range of the European Tapiridae at the species level is proposed for the Oligocene and early Miocene of Western Europe. The paleoecology of tapirs and their diversity and evolution through the Oligocene\u2014Miocene transition are discussed and compared with contemporaneous large mammals such as Rhinocerotoidea, Anthracotheriidae, and Suoidea.", "keyphrases": ["perissodactyla", "oligocene\u2014miocene transition", "tapiridae"]}
{"id": "paleo.004686", "title": "Intraspecific facial bite marks in tyrannosaurids provide insight into sexual maturity and evolution of bird-like intersexual display", "abstract": "Abstract. Intraspecific aggression, or agonism, is a widespread intrasexual selective behavior important to understanding animal behavioral ecology and reproductive systems. Such behavior can be studied either by direct observation or inferred from wound/scar frequency in extant species but is difficult to document in extinct taxa, limiting understanding of its evolution. Among extant archosaurs, crocodylians display extensive intrasexual aggression, whereas birds show extreme visual/vocal intersexual display. The evolutionary origin of this behavioral divergence, and pattern in non-avian dinosaurs, is unknown. Here we document the morphology, frequency, and ontogeny of intraspecific facial bite lesions (324 lesions) in a large sample of tyrannosaurids (202 specimens, 528 elements) to infer patterns of intraspecific aggression in non-avian theropods. Facial scars are consistent in position and orientation across tyrannosaurid species, suggesting bites were inflicted due to repeated/postured behavior. Facial scars are absent in young tyrannosaurids, first appear in immature animals (\u223c50% adult skull length), are present in \u223c60% of the adult-sized specimens, and show aggressor:victim size isometry. The ontogenetic distribution of bite scars suggests agonistic behavior is associated with the onset of sexual maturity, and scar presence in approximately half the specimens may relate to a sexual pattern. Considered in a phylogenetic context, intraspecific bite marks are consistent and widely distributed in fossil and extant crocodyliforms and non-maniraptoriform theropods, suggesting a potential plesiomorphic behavior in archosaurs. Their absence in maniraptoriform theropods, including birds, may reflect a transition from boney cranial ornamentation and crocodylian-like intrasexual aggression to avian-like intersexual display with the evolution of pennaceous feathers.", "keyphrases": ["bite mark", "tyrannosaurid", "sexual maturity"]}
{"id": "paleo.010808", "title": "Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record", "abstract": "To date, eco-evolutionary dynamics in the ascent of tyrannosauroids to top predator roles have been obscured by a 70-million-year gap in the North American (NA) record. Here we report discovery of the oldest Cretaceous NA tyrannosauroid, extending the lineage by ~15 million years. The new taxon\u2014Moros intrepidus gen. et sp. nov.\u2014is represented by a hind limb from an individual nearing skeletal maturity at 6\u20137 years. With a ~1.2-m limb length and 78-kg mass, M. intrepidus ranks among the smallest Cretaceous tyrannosauroids, restricting the window for rapid mass increases preceding the appearance of colossal eutyrannosaurs. Phylogenetic affinity with Asian taxa supports transcontinental interchange as the means by which iconic biotas of the terminal Cretaceous were established in NA. The unexpectedly diminutive and highly cursorial bauplan of NA\u2019s earliest Cretaceous tyrannosauroids reveals an evolutionary strategy reliant on speed and small size during their prolonged stint as marginal predators.", "keyphrases": ["tyrannosauroid", "70-million-year gap", "tyrannosaur", "moros"]}
{"id": "paleo.009778", "title": "DNA from resin-embedded organisms: Past, present and future", "abstract": "Past claims have been made for fossil DNA recovery from various organisms (bacteria, plants, insects and mammals, including humans) dating back in time from thousands to several million years BP. However, many of these recoveries, especially those described from million-year-old amber (fossil resin), have faced criticism as being the result of modern environmental contamination and for lack of reproducibility. Using modern genomic techniques, DNA can be obtained with confidence from a variety of substrates (e.g. bones, teeth, gum, museum specimens and fossil insects) of different ages, albeit always less than one million years BP, and results can also be obtained from much older materials using palaeoproteomics. Nevertheless, new attempts to determine if ancient DNA (aDNA) is present in insects preserved in 40 000-year old sub-fossilised resin, the precursor of amber, have been unsuccessful or not well documented. Resin-embedded specimens are therefore regarded as unsuitable for genetic studies. However, we demonstrate here, for the first time, that although a labile molecule, DNA is still present in platypodine beetles (Coleoptera: Curculionidae) embedded in six-year-old and two-year-old resin pieces from Hymenaea verrucosa (Angiospermae: Fabaceae) collected in Madagascar. We describe an optimised method which meets all the requirements and precautions for aDNA experiments for our purpose: to explore the DNA preservation limits in resin. Our objective is far from starting an uncontrolled search for aDNA in amber as it was in the past, but to start resolving basic aspects from the DNA preservation in resin and search from the most modern samples to the ancient ones, step by step. We conclude that it is therefore possible to study genomics from resin-embedded organisms, although the time limits remain to be determined.", "keyphrases": ["resin-embedded organism", "resin", "dna"]}
{"id": "paleo.012068", "title": "The oldest record of aquatic amniote congenital scoliosis", "abstract": "We report the first occurrence of congenital scoliosis in an early Permian aquatic parareptile, Stereosternum tumidum from Paran\u00e1 state, Brazil. The spine malformation is caused by a congenital hemivertebra. These observations give insight into the biomechanical aspects of underwater locomotion in an axial skeleton-compromised aquatic amniote. This is the oldest record of a hemivertebra in an aquatic animal.", "keyphrases": ["amniote", "congenital scoliosis", "hemivertebra"]}
{"id": "paleo.001681", "title": "Strangers in a strange land: Ecological dissimilarity to metatherian carnivores may partly explain early colonization of South America by Cyonasua-group procyonids", "abstract": "It was once thought that the endemic carnivorous mammals of South America, the metatherian sparassodonts, were driven extinct by North American carnivorans through competitive exclusion. However, sparassodonts went extinct before most groups of carnivorans entered South America; only the endemic Cyonasua-group procyonids (Cyonasua and Chapalmalania), which immigrated to South America nearly 4 million years earlier than other carnivorans, significantly overlapped with sparassodonts in time. In this study, we examine the functional morphology of the dentition of Cyonasua and Chapalmalania through quantitative analysis to determine the dietary habits of these taxa and the degree to which they may have ecologically overlapped sparassodonts and large predatory Neogene didelphimorphians. We find Cyonasua and Chapalmalania to be more carnivorous than extant procyonids, other than Bassariscus, in agreement with previous studies, but more omnivorous than most other carnivorans and all meat-eating South American metatherians, including sparassodonts. The extreme ecological dissimilarity between Cyonasuagroup procyonids and members of the endemic South American predator guild may explain why procyonids were able to successfully establish themselves in South America several million years earlier than most other northern mammals (including all other carnivorans): they moved into a previously unoccupied ecological niche (large omnivore) and avoided direct competition with incumbent native species, a situation similar to that documented in historical cases of biological invasion. The omnivorous diets and climbing/swimming abilities of procyonids may have increased their chances for a successful over-water dispersal relative to other carnivorans, further favoring their successful establishment in South America.", "keyphrases": ["ecological dissimilarity", "south america", "cyonasua-group procyonid"]}
{"id": "paleo.002013", "title": "Silicified otoliths from the Maastrichtian type area (Netherlands, Belgium) document early gadiform and perciform fishes during the Late Cretaceous, prior to the K/Pg boundary extinction event", "abstract": "The Maastrichtian is an important time interval in the evolution of modern bony fishes. Certain teleost groups that disappeared later during the catastrophic K/Pg boundary extinction event, flourished during this period, while the root stock of other groups that subsequently filled the void and evolved, were already represented. Otoliths constitute an important data set for the reconstruction of extinct teleost faunas and are often found to complement information gained from skeletal remains. Here we describe otoliths obtained from the type area of the Maastrichtian Stage, from various levels within the Maastricht Formation. This assemblage is unique in being preserved as silicified neomorphs and reflects a shallowmarine carbonate environment which is rarely preserved for otolith associations. A total of 49 specimens were recovered from the upper Maastrichtian of the Maastricht Formation, of which 39 could be identified and belong to 15 species, plus one from the overlying Danian. New insight is gained into early gadiform and perciform (sensu lato) diversification. Three new taxa are described: Archaemacruroides vanknippenbergi n. sp. (Gadiformes incertae sedis), Rhinocephalus cretaceus n. sp. (Gadiformes, Merlucciidae) and Cretaserranus maastrichtensis n. gen. et sp. (Perciformes, Serranidae?).", "keyphrases": ["otolith", "maastrichtian type area", "silicified otolith"]}
{"id": "10.1127/nos/2017/0354", "title": "Identifying the onset of the Messinian salinity crisis: a reassessment of the biochronostratigraphic tools (Piedmont Basin, NW Italy)", "abstract": "At the end of the Miocene, water exchange between the Mediterranean Sea and the world ocean was severely reduced, leading to deposition of huge volumes of evaporites during the Messinian salinity crisis (MSC). The onset of this event has been precisely dated at 5.971 Ma by means of magneto-, bio- and cyclostratigraphic tools, but clear paleobiological proxies for its recognition are so far missing, especially in those basins in which evaporite deposition is delayed. The disappearence of calcareous microfossils was the only paleobiological signal used to approximate the beginning of the crisis, but recently calcareous plankton has been recorded above the onset in several sections. Calcareous nannofossil and planktonic foraminifer data from the Piedmont Basin indicate that the cycle recording the beginning of the crisis is characterized by a peculiar succession 35 36 37 38 44 of bioevents. These bioevents are (i) a calcareous nannofossil Sphenolithus abies abundance peak, followed or accompanied by minor peaks of Helicosphaera carteri , Umbilicosphara rotula and Rhabdosphaera procera , and (ii) the planktonic foraminifer Globorotalia scitula and G. suterae influx. The same sequence of bioevents has been recorded in sections from the Eastern and Central Mediterranean (Pissouri and Tokhni sections in Cyprus; Fanantello section in the Apennines) within the same age range. We thus propose that the S. abies and U. rotula peaks (often accompanied by minor peaks of H. carteri and R. procera) provide a reliable tool for the identification of the onset of the MSC independently from the occurrence of evaporites. This is particularly useful when studying successions deposited in intermediate- and deep-water basins, where evaporites are absent or their deposition is delayed. Our findings can potentially provide a reliable proxy for the identification of the MSC onset in deep-sea cores.", "keyphrases": ["messinian salinity crisis", "piedmont basin", "succession"]}
{"id": "10.1098/rstb.1998.0195", "title": "Terrestrial-marine teleconnections in the Devonian: links between the evolution of land plants, weathering processes, and marine anoxic events", "abstract": "The Devonian Period was characterized by major changes in both the terrestrial biosphere, e.g. the evolution of trees and seed plants and the appearance of multi-storied forests, and in the marine biosphere, e.g. an extended biotic crisis that decimated tropical marine benthos, especially the stromatoporoid-tabulate coral reef community. Teleconnections between these terrestrial and marine events are poorly understood, but a key may lie in the role of soils as a geochemical interface between the lithosphere and atmosphere/hydrosphere, and the role of land plants in mediating weathering processes at this interface. The effectiveness of terrestrial floras in weathering was significantly enhanced as a consequence of increases in the size and geographic extent of vascular land plants during the Devonian. In this regard, the most important palaeobotanical innovations were (1) arborescence (tree stature), which increased maximum depths of root penetration and rhizoturbation, and (2) the seed habit, which freed land plants from reproductive dependence on moist lowland habitats and allowed colonization of drier upland and primary successional areas. These developments resulted in a transient intensification of pedogenesis (soil formation) and to large increases in the thickness and areal extent of soils. Enhanced chemical weathering may have led to increased riverine nutrient fluxes that promoted development of eutrophic conditions in epicontinental seaways, resulting in algal blooms, widespread bottomwater anoxia, and high sedimentary organic carbon fluxes. Long-term effects included drawdown of atmospheric pCO2 and global cooling, leading to a brief Late Devonian glaciation, which set the stage for icehouse conditions during the Permo-Carboniferous. This model provides a framework for understanding links between early land plant evolution and coeval marine anoxic and biotic events, but further testing of Devonian terrestrial-marine teleconnections is needed.", "keyphrases": ["devonian", "land plant", "terrestrial-marine teleconnection"]}
{"id": "10.1017/pab.2015.41", "title": "The dipnoan buccal pump reconstructed in 3D and implications for air breathing in Devonian lungfishes", "abstract": "Abstract. Lungfishes are known for, and indeed take their name from, their bimodal respiratory abilities. All three extant genera can use their lungs to extract oxygen from the atmosphere, although their reliance upon this capability differs among taxa. Lungs are considered primitive for the Osteichthyes, however the distinctive buccal pump mode of air gulping exhibited by extant lungfishes appears to be a specialization. It is associated with a number of derived skeletal characters (cranial ribs, long parasphenoid stalk, midline gap between palatal tooth plates) that first appeared during the Devonian. These have been described individually, but in no Devonian lungfish has their three-dimensional (3D) spatial relationship been reconstructed and analyzed. Here we present the 3D morphology of Rhinodipterus, a Mid-Late Devonian lungfish from Australia and Europe, based on synchrotron tomography and conventional microtomography scans. Unlike less crownward contemporaneous lungfishes such as Griphognathus and Chirodipterus, Rhinodipterus has a full set of skeletal buccal pump components that can be directly compared to those of extant lungfishes, suggesting that it made more extensive use of air breathing than other Gogo or Bergisch Gladbach genera. This is interesting in relation to the environmental context as Gogo and Bergisch Gladbach are both marine, contrasting with the frequently hypoxic tropical to subtropical fresh water environments inhabited by modern lungfishes. The evolution of buccal pump-supported lung ventilation was evidently not necessarily associated with a transition to non-marine habitats.", "keyphrases": ["air breathing", "lungfish", "cranial rib"]}
{"id": "10.1111/j.1469-8137.2012.04091.x", "title": "The evolution of reproductive structures in seed plants: a re-examination based on insights from developmental genetics.", "abstract": "The study of developmental genetics is providing insights into how plant morphology can and does evolve, and into the fundamental nature of specific organs. This new understanding has the potential to revise significantly the way we think about seed plant evolution, especially with regard to reproductive structures. Here, we have sought to take a step in bridging the divide between genetic data and critical fields such as paleobotany and systematics. We discuss the evidence for several evolutionarily important interpretations, including the possibility that ovules represent meristematic axes with their own type of lateral determinate organs (integuments) and a model that considers carpels as analogs of complex leaves. In addition, we highlight the aspects of reproductive development that are likely to be highly labile and homoplastic, factors that have major implications for the understanding of seed plant relationships. Although these hypotheses may suggest that some long-standing interpretations are misleading, they also open up whole new avenues for comparative study and suggest concrete best practices for evolutionary analyses of development.", "keyphrases": ["reproductive structure", "developmental genetic", "organ"]}
{"id": "10.1111/j.1502-3931.2009.00206.x", "title": "The Devonian nekton revolution", "abstract": "Klug, C., Kroger, B., Kiessling, W., Mullins, G.L., Servais, T., Fr\u00fdda, J., Korn, D. & Turner, S. 2009: The Devonian nekton revolution. Lethaia, 10.1111/j.1502-3931.2009.00206.x \n \nTraditional analyses of Early Phanerozoic marine diversity at the genus level show an explosive radiation of marine life until the Late Ordovician, followed by a phase of erratic decline continuing until the end of the Palaeozoic, whereas a more recent analysis extends the duration of this early radiation into the Devonian. This catch-all approach hides an evolutionary and ecological key event long after the Ordovician radiation: the rapid occupation of the free water column by animals during the Devonian. Here, we explore the timing of the occupation of the water column in the Palaeozoic and test the hypothesis that ecological escalation led to fundamental evolutionary changes in the mid-Palaeozoic marine water column. According to our analyses, demersal and nektonic modes of life were probably initially driven by competition in the diversity-saturated benthic habitats together with the availability of abundant planktonic food. Escalatory feedback then promoted the rapid rise of nekton in the Devonian as suggested by the sequence and tempo of water-column occupation. \u25a1Devonian, diversity, ecology, food webs, nekton, plankton, radiation.", "keyphrases": ["devonian nekton revolution", "marine diversity", "palaeozoic"]}
{"id": "paleo.009191", "title": "A New Basal Sauropod Dinosaur from the Middle Jurassic of Niger and the Early Evolution of Sauropoda", "abstract": "Background The early evolution of sauropod dinosaurs is poorly understood because of a highly incomplete fossil record. New discoveries of Early and Middle Jurassic sauropods have a great potential to lead to a better understanding of early sauropod evolution and to reevaluate the patterns of sauropod diversification. Principal Findings A new sauropod from the Middle Jurassic of Niger, Spinophorosaurus nigerensis n. gen. et sp., is the most complete basal sauropod currently known. The taxon shares many anatomical characters with Middle Jurassic East Asian sauropods, while it is strongly dissimilar to Lower and Middle Jurassic South American and Indian forms. A possible explanation for this pattern is a separation of Laurasian and South Gondwanan Middle Jurassic sauropod faunas by geographic barriers. Integration of phylogenetic analyses and paleogeographic data reveals congruence between early sauropod evolution and hypotheses about Jurassic paleoclimate and phytogeography. Conclusions Spinophorosaurus demonstrates that many putatively derived characters of Middle Jurassic East Asian sauropods are plesiomorphic for eusauropods, while South Gondwanan eusauropods may represent a specialized line. The anatomy of Spinophorosaurus indicates that key innovations in Jurassic sauropod evolution might have taken place in North Africa, an area close to the equator with summer-wet climate at that time. Jurassic climatic zones and phytogeography possibly controlled early sauropod diversification.", "keyphrases": ["jurassic", "niger", "early evolution", "sauropoda", "spinophorosaurus"]}
{"id": "paleo.009026", "title": "The African ape-like foot of Ardipithecus ramidus and its implications for the origin of bipedalism", "abstract": "The ancestral condition from which humans evolved is critical for understanding the adaptive origin of bipedal locomotion. The 4.4 million-year-old hominin partial skeleton attributed to Ardipithecus ramidus preserves a foot that purportedly shares morphometric affinities with monkeys, but this interpretation remains controversial. Here I show that the foot of Ar. ramidus is most similar to living chimpanzee and gorilla species among a large sample of anthropoid primates. The foot morphology of Ar. ramidus suggests that the evolutionary precursor of hominin bipedalism was African ape-like terrestrial quadrupedalism and climbing. The elongation of the midfoot and phalangeal reduction in Ar. ramidus relative to the African apes is consistent with hypotheses of increased propulsive capabilities associated with an early form of bipedalism. This study provides evidence that the modern human foot was derived from an ancestral form adapted to terrestrial plantigrade quadrupedalism.", "keyphrases": ["foot", "ardipithecus ramidus", "bipedalism", "chimpanzee"]}
{"id": "10.1111/j.1096-3642.1997.tb01286.x", "title": "Systematic relationships of the palaeogene family Presbyornithidae (Aves: Anseriformes)", "abstract": "Abstract The early Tertiary (Paleocene and Eocene) family Presbyornithidae is one of the most completely known group of fossil birds. Essentially all parts of the skeleton are represented in the fossil record, allowing a thorough analysis of the phylogenetic position of the family. Forty-two families of nonpasserine birds representing the orders Ciconiiformes, Anseriformes, Galliformes, Gruiformes and Charadriiformes, were included in a cladistic analysis of 71 skeletal characters. The previously suggested anseriform affinity of the Presbyornithidae was confirmed. Furthermore, the family proved to be closer to the Anatidae than to the Anhimidae or Anseranatidae. The many postcranial similarities with certain charadriiform birds as the Burhinidae, obviously are plesiomorphies. By this observation, a better undestanding of character evolution in nonpasserine skeletal morphology is gained. The often suggested close relationship of anseriform and galliform birds is not confirmed by osteology. Instead, the Anseriformes and the Phoenicopteridae form a monophyletic clade that is the sister to the remaining ciconiiform birds. This result renders the CiconiiformessensuWetmore (1960) polyphyletic.", "keyphrases": ["family presbyornithidae", "anseriformes", "anatidae"]}
{"id": "10.1080/14772011003603556", "title": "The phylogeny and classification of post-Palaeozoic echinoids", "abstract": "The relationships of post-Palaeozoic echinoids at family level are established through phylogenetic analysis of 169 taxa and 306 skeletal characters (excluding pedicellariae). Previous phylogenetic analyses of echinoids have either examined specific subgroups in detail or have looked at a relatively small number of taxa selected from across the class, with sparse sampling potentially affecting the reliability of results adversely. Our new analyses represent a compromise between encompassing the diversity of form that exists, while keeping the number of taxa to a level that does not make rigorous analysis impossibly time-consuming. In constructing the taxon-character data matrix we have encountered a surprising lack of primary data on plating pattern, lantern, and girdle structure for many supposedly \u201cwell-known\u201d taxa. A well-resolved phylogenetic hypothesis was obtained and is used as the basis for a formal classification. Characters generally have a high retention index (>0.7) but low consistency index (<0.25) suggesting that, although characters are largely retained after they first evolve, most also undergo occasional reversal or convergence. Although parts of the resulting trees are only weakly supported (e.g. the precise sister group of the Irregularia), other parts are unambiguously resolved. Not unexpectedly, deep nodes are often not supported by unique apomorphies and higher taxa acquire their characteristic set of features over time. Diagnoses based on crown group taxa thus often fail to encompass fossil stem-group members adequately. Establishing the relationships of taxa at the root of large groups is hampered by limited character resolution. The influence of fossil taxa on the topology was explored by comparing the tree topologies obtained with and without their inclusion. We show that removal of fossils from stem groups makes no difference where their crown group is morphologically conservative, but has a major influence where extant sister groups are separated by large morphological gaps. Completeness of the echinoid record and its match to the stratigraphical record of first occurrences is tested using various metrics and found to be highly congruent, with irregular echinoids showing a higher congruence than regular ones.", "keyphrases": ["post-palaeozoic echinoid", "echinoid", "phylogenetic analysis", "crown group"]}
{"id": "10.1130/G45480.1", "title": "Synchronous cooling and decline in monsoonal rainfall in northeastern Tibet during the fall into the Oligocene icehouse", "abstract": "The fall into the Oligocene icehouse is marked by a steady decline in global temperature with punctuated cooling at the Eocene-Oligocene transition, both of which are well documented in the marine realm. However, the chronology and mechanisms of cooling on land remain unclear. Here, we use clumped isotope thermometry on northeastern Tibetan continental carbonates to reconstruct a detailed Paleogene surface temperature record for the Asian continental interior, and correlate this to an enhanced pollen data set. Our results show two successive dramatic (>9 \u00b0C) temperature drops, at 37 Ma and at 33.5 Ma. These large-magnitude decreases in continental temperatures can only be explained by a combination of both regional cooling and shifts of the rainy season to cooler months, which we interpret to reflect a decline of monsoonal intensity. Our results suggest that the response of Asian surface temperatures and monsoonal rainfall to the steady decline of atmospheric CO2 and global temperature through the late Eocene was nonlinear and occurred in two steps separated by a period of climatic instability. Our results support the onset of the Antarctic Circumpolar Current coeval to the Oligocene isotope event 1 (Oi-1) glaciation at 33.5 Ma, reshaping the distribution of surface heat worldwide; however, the origin of the 37 Ma cooling event remains less clear.", "keyphrases": ["cooling", "monsoonal rainfall", "oligocene icehouse"]}
{"id": "paleo.000177", "title": "Osteological Correlates for Quadrupedality in Ornithischian Dinosaurs", "abstract": "The evolution of quadrupedality from bipedal ancestors is an exceptionally rare transition in tetrapod evolution, but it has occurred several times within the herbivorous dinosaur clade Ornithischia. Stegosauria, Ankylosauria, and Ceratopsidae are all uncontroversially quadrupedal, while basal ornithischians and basal ornithopods are uncontroversially bipedal. However, stance in iguanodontian ornithopods, including the hadrosaurs, and in non-ceratopsid ceratopsians is debated because robust osteological correlates of quadrupedality have not been identified. We examine a suite of characteristics that have been previously proposed as osteological correlates for bipedality or quadrupedality in dinosaurs. These include both discrete anatomical features, which we assess as correlates for quadrupedality using character optimization onto a composite cladogram, and proportional ratios, which we assess as correlates by reconstructing nodal ancestral states using squared-change parsimony, followed by optimization. We also examine the correlation of these features with body size. An anterolateral process on the proximal ulna, hoof-shaped manual unguals, a transversely broadened ilium, a reduced fourth trochanter and a femur longer than the tibia are found to be robust correlates of quadrupedality in ornithischian dinosaurs. Along the ceratopsid \u201cstem\u201d lineage, quadrupedal characters were acquired in a stepwise fashion, with forelimb characters developing prior to changes in the hind limb. In contrast, iguanodontid ornithopods display a mosaic of character states, indicating varying degrees of facultative quadrupedality that probably arose for a variety of different reasons. Hadrosaurs are found to possess all character states associated with quadrupedality and were probably predominantly quadrupedal. In general, quadrupedal ornithischians do not appear to have been constrained by their bipedal ancestry to a particular order of character acquisition.", "keyphrases": ["quadrupedality", "ornithischian dinosaur", "osteological correlate"]}
{"id": "10.1098/rspb.2010.1754", "title": "Sea level, dinosaur diversity and sampling biases: investigating the \u2018common cause\u2019 hypothesis in the terrestrial realm", "abstract": "The fossil record is our primary window onto the diversification of ancient life, but there are widespread concerns that sampling biases may distort observed palaeodiversity counts. Such concerns have been reinforced by numerous studies that found correlations between measures of sampling intensity and observed diversity. However, correlation does not necessarily mean that sampling controls observed diversity: an alternative view is that both sampling and diversity may be driven by some common factor (e.g. variation in continental flooding driven by sea level). The latter is known as the \u2018common cause\u2019 hypothesis. Here, we present quantitative analyses of the relationships between dinosaur diversity, sampling of the dinosaur fossil record, and changes in continental flooding and sea level, providing new insights into terrestrial common cause. Although raw data show significant correlations between continental flooding/sea level and both observed diversity and sampling, these correlations do not survive detrending or removal of short-term autocorrelation. By contrast, the strong correlation between diversity and sampling is robust to various data transformations. Correlations between continental flooding/sea level and taxic diversity/sampling result from a shared upward trend in all data series, and short-term changes in continental flooding/sea level and diversity/sampling do not correlate. The hypothesis that global dinosaur diversity is tied to sea-level fluctuations is poorly supported, and terrestrial common cause is unsubstantiated as currently conceived. Instead, we consider variation in sampling to be the preferred null hypothesis for short-term diversity variation in the Mesozoic terrestrial realm.", "keyphrases": ["dinosaur diversity", "terrestrial realm", "fluctuation", "sea level"]}
{"id": "paleo.002568", "title": "Late Cretaceous sturgeons (Acipenseridae) from North America, with two new species from the Tanis site in the Hell Creek Formation of North Dakota", "abstract": "Abstract. Although the Cretaceous is widely regarded as a time of great evolutionary transition for the freshwater fish fauna of North America, the fossil record of this period is notoriously poor, consisting mostly of fragments and isolated skeletal elements. Exceptions include the acipenseriforms, discussed in this paper, and some exceedingly rare teleosts. Here we describe two new species of well-preserved sturgeons (Acipenseridae) from the Tanis site in the Late Cretaceous Hell Creek Formation of North Dakota. The type and referred materials were preserved in a loosely consolidated matrix. \u2020Acipenser praeparatorum n. sp. is represented by multiple body fossils (including the head and relatively complete postcranial remains) and a specimen of an intact, three dimensionally preserved skull and pectoral girdle. This taxon can be diagnosed based on features of the opercular elements (exceptionally tall and narrow branchiostegal). The second species, \u2020Acipenser anisinferos n. sp., is represented by a partially preserved skull, and can be diagnosed by a relatively elongate preorbital region (i.e., snout) and the absence of thorn-like spines on the skull roofing bones. Most known sturgeon fossils from the Cretaceous are represented only by undiagnosable fragmentary remains (i.e., scutes and pectoral-fin spines) or poorly preserved partial skeletons (e.g., \u2020Protoscaphirhynchus), with \u2020Priscosturion and \u2020Anchiacipenser (both monotypic) being rare exceptions. Therefore, the newly discovered Tanis fossils give a rare glimpse into the evolution of Acipenseridae at a critical time in the phylogenetic history of acipenseriforms, and suggest significant morphological and taxonomic diversity early in the evolution of this group.", "keyphrases": ["acipenseridae", "tanis site", "north dakota"]}
{"id": "paleo.000862", "title": "Intergrowth of Orbignyella germana Bassler, 1911 (Bryozoa) and Lambelasma carinatum Weyer, 1993 (Rugosa) in the pelmatozoan-bryozoan-receptaculitid reefs from the Late Ordovician of Estonia", "abstract": "The earliest known rugosan-bryozoan intergrowth is reported from the early Katian of Estonia. A specimen of Orbignyella germana Bassler, 1911, from pelmatozoan-bryozoan-receptaculitid reefs of the Vasalemma Formation shows intergrowth with rugosans Lambelasma carinatum Weyer, 1993. The morphology of the bryozoan colony does not show any malformations or changes in zooid size near the embedded rugosans. It is likely that intergrowth between L. carinatum and O. germana was purely accidental. Relatively high population densities and restricted space for growth in the reef may have caused this intergrowth. Rugosans may have benefitted from this association in achieving a stable substrate in shallow and hydrodynamically active waters of the reef environment, whereas bryozoans obviously used corals as a substrate. Lambelasma may have been especially prone for intergrowth with bryozoans as it participates in three associations in the Late Ordovician of Estonia. Olev Vinn. Department of Geology, University of Tartu, Ravila 14A, 50411 Tartu, Estonia; olev.vinn@ut.ee Ursula Toom. Department of Geology, Tallinn University of Technology, Ehitajate tee 5, 19086 Tallinn, Estonia; ursula.toom@ttu.ee Andrej Ernst. Institut f\u00fcr Geologie, Universit\u00e4t Hamburg, Bundesstr. 55, 20146 Hamburg, Germany; Andrej.Ernst@uni-hamburg.de", "keyphrases": ["bryozoa", "pelmatozoan-bryozoan-receptaculitid reef", "intergrowth"]}
{"id": "10.1080/02724634.2015.1031343", "title": "New Avian Remains from the Paleocene of New Zealand: The First Early Cenozoic Phaethontiformes (Tropicbirds) from the Southern Hemisphere", "abstract": "Citation for this article: Mayr, G., and R. P. Scofield. 2015. New avian remains from the Paleocene of New Zealand: the first early Cenozoic Phaethontiformes (tropicbirds) from the Southern Hemisphere. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1031343.", "keyphrases": ["paleocene", "new zealand", "new avian"]}
{"id": "paleo.001212", "title": "The hand of Homo naledi", "abstract": "A nearly complete right hand of an adult hominin was recovered from the Rising Star cave system, South Africa. Based on associated hominin material, the bones of this hand are attributed to Homo naledi. This hand reveals a long, robust thumb and derived wrist morphology that is shared with Neandertals and modern humans, and considered adaptive for intensified manual manipulation. However, the finger bones are longer and more curved than in most australopiths, indicating frequent use of the hand during life for strong grasping during locomotor climbing and suspension. These markedly curved digits in combination with an otherwise human-like wrist and palm indicate a significant degree of climbing, despite the derived nature of many aspects of the hand and other regions of the postcranial skeleton in H. naledi.", "keyphrases": ["hand", "wrist morphology", "modern human", "frequent use", "climbing"]}
{"id": "paleo.008376", "title": "A new gecko from the earliest Eocene of Dormaal, Belgium: a thermophilic element of the \u2018greenhouse world\u2019", "abstract": "We here describe a new gekkotan lizard from the earliest Eocene (MP 7) of the Dormaal locality in Belgium, from the time of the warmest global climates of the past 66 million years (Myr). This new taxon, with an age of 56 Myr, together with indeterminate gekkotan material reported from Silveirinha (Portugal, MP 7) represent the oldest Cenozoic gekkotans known from Europe. Today gekkotan lizards are distributed worldwide in mainly warm temperate to tropical areas and the new gecko from Dormaal represents a thermophilic faunal element. Given the Palaeocene\u2013Eocene thermal maximum at that time, the distribution of this group in such northern latitudes (above 50\u00b0 North \u2013 the latitude of southern England) is not surprising. Although this new gekkotan is represented only by a frontal (further, dentaries and a mandibular fragment are described here as Gekkota indet. 1 and 2\u2014at least two gekkotan species occurred in Dormaal), it provides a new record for squamate diversity from the earliest Eocene \u2018greenhouse world\u2019. Together with the Baltic amber gekkotan Yantarogekko balticus, they document the northern distribution of gekkotans in Europe during the Eocene. The increase in temperature during the early Eocene led to a rise in sea level, and many areas of Eurasia were submerged. Thus, the importance of this period is magnified by understanding future global climate change.", "keyphrases": ["new gecko", "dormaal", "early eocene"]}
{"id": "paleo.007492", "title": "Mechanisms and drivers of belemnite body-size dynamics across the Pliensbachian\u2013Toarcian crisis", "abstract": "Body-size reduction is considered an important response to current climate warming and has been observed during past biotic crises, including the Pliensbachian\u2013Toarcian crisis, a second-order mass extinction. However, in fossil cephalopod studies, the mechanisms and their potential link with climate are rarely investigated and palaeobiological scales of organization are not usually differentiated. Here, we hypothesize that belemnites reduce their adult size across the Pliensbachian\u2013Toarcian boundary warming event. Belemnite body-size dynamics across the Pliensbachian\u2013Toarcian boundary in the Peniche section (Lusitanian Basin, Portugal) were analysed based on the newly collected field data. We disentangle the mechanisms and the environmental drivers of the size fluctuations observed from the individual to the assemblage scale. Despite the lack of a major taxonomic turnover, a 40% decrease in rostrum volume is observed across the Pliensbachian\u2013Toarcian boundary, before the Toarcian Oceanic Anoxic Event where belemnites go locally extinct. The pattern is mainly driven by a reduction in adult size of the two dominant species, Pseudohastites longiformis and Passaloteuthis bisulcata. Belemnite-size distribution is best correlated with fluctuations in a palaeotemperature proxy (stable oxygen isotopes); however, potential indirect effects of volcanism and carbon cycle perturbations may also play a role. This highlights the complex interplay between environmental stressors (warming, deoxygenation, nutrient input) and biotic variables (productivity, competition, migration) associated with these hyperthermal events in driving belemnite body-size.", "keyphrases": ["belemnite body-size dynamic", "pliensbachian\u2013toarcian crisis", "crisis"]}
{"id": "10.1017/jpa.2017.84", "title": "New smallest specimen of the pterosaur Pteranodon and ontogenetic niches in pterosaurs", "abstract": "Abstract. \n A new juvenile specimen of Pteranodon from the Smoky Hill Chalk Member of the Niobrara Formation of western Kansas had an estimated wingspan in life of 1.76 m, \u223c 45% smaller than the smallest previously known specimens, but does not differ in morphology from larger specimens. Its presence indicates that juveniles were capable of flying long distances, so it falsifies the interpretation of Pteranodon as growing rapidly to adult size under parental care before flying. Instead juveniles were precocial, growing more slowly to adult size while flying and feeding independently for several years before going to sea. Because juveniles are otherwise unknown in the Smoky Hill Chalk Member, they must have occupied different environments and ecological niches than adults; thus Pteranodon exhibited ontogenetic niches. Evidence is presented that most other pterosaurs (e.g., Rhamphorhynchus, Pterodactylus, Anhanguera) also exhibited various ontogenetic niches, which, along with their large body size, suggests that pterosaur taxonomic diversity was rather low, like that of crocodilians.", "keyphrases": ["pteranodon", "ontogenetic niche", "juvenile"]}
{"id": "paleo.003761", "title": "A Large Predatory Archosaur from the Late Triassic of Poland", "abstract": "We describe a new large predatory archosaur, Smok wawelski gen. et sp. nov., from the latest Triassic (latest Norian\u2014early Rhaetian; approximately 205\u2013200 Ma) of Lisowice (Lipie \u015al\u0105skie clay-pit) in southern Poland. The length of the reconstructed skeleton is 5\u20136 m and that of the skull 50\u201360 cm, making S. wawelski larger than any other known predatory archosaur from the Late Triassic and Early Jurassic of central Europe (including theropod dinosaurs and \u201crauisuchian\u201d crurotarsans). The holotype braincase is associated with skull, pelvic and isolated limb-bones found in close proximity (within 30 m), and we regard them as belonging to the same individual. Large, apparently tridactyl tracks that occur in the same rock unit may have been left by animals of the same species. The highly autapomorphic braincase shows large attachment areas for hypertrophied protractor pterygoideus muscles on the lateral surface and a wide, funnel-like region between the basal tubera and basipterygoid processes on the ventral surface. The skeleton (cranial and postcranial) possesses some features similar to those in theropod dinosaurs and others to those in large crocodile-line archosaurs (\u201crauisuchians\u201d), rendering phylogenetic placement of S. wawelski difficult at this time.", "keyphrases": ["large predatory archosaur", "late triassic", "poland", "lipie \u015bl\u0105skie clay-pit", "aquatic tetrapod"]}
{"id": "10.1073/pnas.1113993109", "title": "Spatial and temporal arrival patterns of Madagascar's vertebrate fauna explained by distance, ocean currents, and ancestor type", "abstract": "How, when, and from where Madagascar's vertebrates arrived on the island is poorly known, and a comprehensive explanation for the distribution of its organisms has yet to emerge. We begin to break that impasse by analyzing vertebrate arrival patterns implied by currently existing taxa. For each of 81 clades, we compiled arrival date, source, and ancestor type (obligate freshwater, terrestrial, facultative swimmer, or volant). We analyzed changes in arrival rates, with and without adjusting for clade extinction. Probability of successful transoceanic dispersal is negatively correlated with distance traveled and influenced by ocean currents and ancestor type. Obligate rafters show a decrease in probability of successful transoceanic dispersal from the Paleocene onward, reaching the lowest levels after the mid-Miocene. This finding is consistent with a paleoceanographic model [Ali JR, Huber M (2010) Nature 463:653\u2013656] that predicts Early Cenozoic surface currents periodically conducive to rafting or swimming from Africa, followed by a reconfiguration to present-day flow 15\u201320 million years ago that significantly diminished the ability for transoceanic dispersal to Madagascar from the adjacent mainland.", "keyphrases": ["madagascar", "ocean current", "ancestor type"]}
{"id": "paleo.005511", "title": "The oldest semi-aquatic beaver in the world and a new hypothesis for the evolution of locomotion in Castoridae", "abstract": "The North American rodent fossil record includes hundreds of species representing both an incredible taxonomic diversity and great ecological disparity. Although it is during the Oligocene that taxonomic diversity first peaks, it is not until the Miocene, almost 10 Myr later, that many ecologies, particularly locomotory ecologies, are recorded. Here, I present a new Oligocene-aged species of beaver from Montana, Microtheriomys articulaquaticus sp. nov., which represents the oldest semi-aquatic rodent in North America and the oldest amphibious beaver in the world, pushing the advent of semi-aquatic ecology in beavers by 7 Myr. I also provide morphological data supporting a terrestrial ecology for the sister taxon to Castoridae. Together with existing data, these findings lead to a new hypothesis for the evolutionary ecology of castorids whereby swimming was exapted from burrowing during the Oligocene. This evolution of semi-aquatic locomotion may have taken place in North America instead of Eurasia. It started in small beavers with gigantism achieved only much later. Indeed, body size evolution in castoroids follows a directional drift. Beavers obey Cope's rule, a selection for larger size over time that appears associated with semi-aquatic ecology and may well explain their low modern diversity.", "keyphrases": ["beaver", "locomotion", "castoridae"]}
{"id": "paleo.004918", "title": "Hyoliths with pedicles illuminate the origin of the brachiopod body plan", "abstract": "Hyoliths are a taxonomically problematic group of Palaeozoic lophotrochozoans that are among the first shelly fossils to appear in the Cambrian period. On the basis of their distinctive exoskeleton, hyoliths have historically been classified as a separate phylum with possible affinities to the molluscs, sipunculans or lophophorates\u2014but their precise phylogenetic position remains uncertain. Here, we describe a new orthothecide hyolith from the Chengjiang Lagerst\u00e4tte (Cambrian Series 2 Stage 3), Pedunculotheca diania Sun, Zhao et Zhu gen. et sp. nov., which exhibits a non-mineralized attachment structure that strikingly resembles the brachiopod pedicle\u2014the first report of a peduncular organ in hyoliths. This organ establishes a sessile, suspension feeding ecology for these orthothecides and\u2014together with other characteristics (e.g. bilaterally symmetrical bivalve shell enclosing a filtration chamber and the differentiation of cardinal areas)\u2014identifies hyoliths as stem-group brachiopods. Our phylogenetic analysis indicates that both hyoliths and crown brachiopods derived from a tommotiid grade, and that the pedicle has a single origin within the brachiopod total group.", "keyphrases": ["pedicle", "mollusc", "phylogenetic position", "hyolith"]}
{"id": "paleo.009315", "title": "Biotic and environmental dynamics through the Late Jurassic\u2013Early Cretaceous transition: evidence for protracted faunal and ecological turnover", "abstract": "The Late Jurassic to Early Cretaceous interval represents a time of environmental upheaval and cataclysmic events, combined with disruptions to terrestrial and marine ecosystems. Historically, the Jurassic/Cretaceous (J/K) boundary was classified as one of eight mass extinctions. However, more recent research has largely overturned this view, revealing a much more complex pattern of biotic and abiotic dynamics than has previously been appreciated. Here, we present a synthesis of our current knowledge of Late Jurassic\u2013Early Cretaceous events, focusing particularly on events closest to the J/K boundary. We find evidence for a combination of short\u2010term catastrophic events, large\u2010scale tectonic processes and environmental perturbations, and major clade interactions that led to a seemingly dramatic faunal and ecological turnover in both the marine and terrestrial realms. This is coupled with a great reduction in global biodiversity which might in part be explained by poor sampling. Very few groups appear to have been entirely resilient to this J/K boundary \u2018event\u2019, which hints at a \u2018cascade model\u2019 of ecosystem changes driving faunal dynamics. Within terrestrial ecosystems, larger, more\u2010specialised organisms, such as saurischian dinosaurs, appear to have suffered the most. Medium\u2010sized tetanuran theropods declined, and were replaced by larger\u2010bodied groups, and basal eusauropods were replaced by neosauropod faunas. The ascent of paravian theropods is emphasised by escalated competition with contemporary pterosaur groups, culminating in the explosive radiation of birds, although the timing of this is obfuscated by biases in sampling. Smaller, more ecologically diverse terrestrial non\u2010archosaurs, such as lissamphibians and mammaliaforms, were comparatively resilient to extinctions, instead documenting the origination of many extant groups around the J/K boundary. In the marine realm, extinctions were focused on low\u2010latitude, shallow marine shelf\u2010dwelling faunas, corresponding to a significant eustatic sea\u2010level fall in the latest Jurassic. More mobile and ecologically plastic marine groups, such as ichthyosaurs, survived the boundary relatively unscathed. High rates of extinction and turnover in other macropredaceous marine groups, including plesiosaurs, are accompanied by the origin of most major lineages of extant sharks. Groups which occupied both marine and terrestrial ecosystems, including crocodylomorphs, document a selective extinction in shallow marine forms, whereas turtles appear to have diversified. These patterns suggest that different extinction selectivity and ecological processes were operating between marine and terrestrial ecosystems, which were ultimately important in determining the fates of many key groups, as well as the origins of many major extant lineages. We identify a series of potential abiotic candidates for driving these patterns, including multiple bolide impacts, several episodes of flood basalt eruptions, dramatic climate change, and major disruptions to oceanic systems. The J/K transition therefore, although not a mass extinction, represents an important transitional period in the co\u2010evolutionary history of life on Earth.", "keyphrases": ["dynamic", "ecological turnover", "mass extinction"]}
{"id": "paleo.012574", "title": "An early modern human from Romania with a recent Neanderthal ancestor", "abstract": "Neanderthals are thought to have disappeared in Europe ~39,000\u201341,000 years ago but they have contributed one to three percent of the DNA of present-day people in Eurasia1. Here, we analyze DNA from a 37,000\u201342,000-year-old2 modern human from Pe\u015ftera cu Oase, Romania. Although the specimen contains small amounts of human DNA, we use an enrichment strategy to isolate sites that are informative about its relationship to Neanderthals and present-day humans. We find that on the order of six to nine percent of the genome of the Oase individual is derived from Neanderthals, more than any other modern human sequenced to date. Three chromosomal segments of Neanderthal ancestry are over 50 centimorgans in size, indicating that this individual had a Neanderthal ancestor as recently as four to six generations back. However, the Oase individual does not share more alleles with later Europeans than with East Asians, suggesting that the Oase population did not contribute substantially to later humans in Europe.", "keyphrases": ["modern human", "romania", "neanderthal ancestor", "europe", "genome"]}
{"id": "paleo.008737", "title": "A partial skeleton of the eomyid Eomyodon volkeri Engesser, 1987 (Mammalia: Rodentia) from the late Oligocene Fossil-Lagerst\u00e4tte of Enspel, Germany", "abstract": "A partial skeleton of a young adult Eomyodon volkeri from the late Oligocene of Enspel (MP 28) represents the first of this genus, which was previously known only from isolated teeth at this locality. The specimen was split in two slabs upon discovery, and both parts were transferred to an artificial plastic matrix. Soft parts are preserved in the partial skeleton which comprises most of the skull with both mandibles, an incomplete vertebral column with parts of the ribcage, the right scapula with a clavicle fragment, almost the entire right forelimb (hand and left radius and ulna), parts of the pelvis and the left hind limb without the foot. It shows a generalised rodent 'bauplan'; body mass is estimated to be about 10 g based on femur length. The lengths and proportions of the phalanges indicate a terrestrial lifestyle, and the preserved soft parts do not indicate any adaptations for gliding.", "keyphrases": ["partial skeleton", "eomyodon volkeri", "oligocene locality enspel"]}
{"id": "paleo.008687", "title": "Microwear patterns on the teeth of northern high latitude hadrosaurs with comments on microwear patterns in hadrosaurs as a function of latitude and seasonal ecological constraints", "abstract": "Dental microwear studies have value in qualitatively addressing patterns of food use in both extinct and extant vertebrates. This study has examined dental microwear patterns on the teeth of Campanian/Maastrichtian hadrosaurs from northern Alaska to western Texas. The primary parameters examined were the incidence of pitting and the orientation of linear features on the occlusal surfaces of the teeth. The results of the examination have shown similar patterns of tooth wear independent of geographic location. Thus it may be that hadrosaurs all along western North America were consuming food items with similar hardness.\nThe dominant food consumed by hadrosaurs is considered to be conifers, although it is unlikely that conifers constituted the entire diet of the high latitude forms given the constraints imposed by a highly seasonal annual cycle. Further, given the similarity of food items consumed along such a large latitudinal gradient, combined with the deciduous nature of the food items in Alaska, it seems likely that northern hadrosaurs reduced their metabolic rates during the winter months, in a manner similar to many modern terrestrial Arctic vertebrates. This reduction in metabolic rate during the winter months may have been facilitated if these animals were inertial homeotherms (i.e., of a low surface: mass ratio) or ectotherms rather than full endotherms.", "keyphrases": ["hadrosaur", "tooth", "microwear"]}
{"id": "paleo.009313", "title": "Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology", "abstract": "Background The best European locality for complete Eocene mammal skeletons is Grube Messel, near Darmstadt, Germany. Although the site was surrounded by a para-tropical rain forest in the Eocene, primates are remarkably rare there, and only eight fragmentary specimens were known until now. Messel has now yielded a full primate skeleton. The specimen has an unusual history: it was privately collected and sold in two parts, with only the lesser part previously known. The second part, which has just come to light, shows the skeleton to be the most complete primate known in the fossil record. Methodology/Principal Findings We describe the morphology and investigate the paleobiology of the skeleton. The specimen is described as Darwinius masillae n.gen. n.sp. belonging to the Cercamoniinae. Because the skeleton is lightly crushed and bones cannot be handled individually, imaging studies are of particular importance. Skull radiography shows a host of teeth developing within the juvenile face. Investigation of growth and proportion suggest that the individual was a weaned and independent-feeding female that died in her first year of life, and might have attained a body weight of 650\u2013900 g had she lived to adulthood. She was an agile, nail-bearing, generalized arboreal quadruped living above the floor of the Messel rain forest. Conclusions/Significance Darwinius masillae represents the most complete fossil primate ever found, including both skeleton, soft body outline and contents of the digestive tract. Study of all these features allows a fairly complete reconstruction of life history, locomotion, and diet. Any future study of Eocene-Oligocene primates should benefit from information preserved in the Darwinius holotype. Of particular importance to phylogenetic studies, the absence of a toilet claw and a toothcomb demonstrates that Darwinius masillae is not simply a fossil lemur, but part of a larger group of primates, Adapoidea, representative of the early haplorhine diversification.", "keyphrases": ["primate", "middle eocene", "germany", "paleobiology", "early haplorhine diversification"]}
{"id": "paleo.013103", "title": "Queen Nefertari, the Royal Spouse of Pharaoh Ramses II: A Multidisciplinary Investigation of the Mummified Remains Found in Her Tomb (QV66)", "abstract": "Queen Nefertari, the favourite Royal Consort of Pharaoh Ramses II (Ancient Egypt, New Kingdom, 19th Dynasty c. 1250 BC) is famous for her beautifully decorated tomb in the Valley of the Queens. Her burial was plundered in ancient times yet still many objects were found broken in the debris when the tomb was excavated. Amongst the found objects was a pair of mummified legs. They came to the Egyptian Museum in Turin and are henceforth regarded as the remains of this famous Queen, although they were never scientifically investigated. The following multidisciplinary investigation is the first ever performed on those remains. The results (radiocarbon dating, anthropology, paleopathology, genetics, chemistry and Egyptology) all strongly speak in favour of an identification of the remains as Nefertari\u2019s, although different explanations\u2014albeit less likely\u2014are considered and discussed. The legs probably belong to a lady, a fully adult individual, of about 40 years of age. The materials used for embalming are consistent with Ramesside mummification traditions and indeed all objects within the tomb robustly support the burial as of Queen Nefertari.", "keyphrases": ["royal spouse", "multidisciplinary investigation", "tomb"]}
{"id": "10.2475/ajs.304.5.397", "title": "COPSE: a new model of biogeochemical cycling over Phanerozoic time", "abstract": "We present a new model of biogeochemical cycling over Phanerozoic time. This work couples a feedback-based model of atmospheric O2 and ocean nutrients (Lenton and Watson, 2000a, 2000b) with a geochemical carbon cycle model (Berner, 1991, 1994), a simple sulfur cycle, and additional components. The resulting COPSE model (Carbon-Oxygen-Phosphorus-Sulfur-Evolution) represents the co-evolution of biotic and abiotic components of the Earth system, in that it couples interactive and evolving terrestrial and marine biota to geochemical and tectonic processes. The model is forced with geological and evolutionary forcings and time-dependent solar insolation. The baseline model succeeds in giving simultaneous predictions of atmospheric O2, CO2, global temperature, ocean composition, \u03b413C and \u03b434S that are in reasonable agreement with available data and suggested constraints. \n \nThe behavior of the coupled model is qualitatively different to single cycle models. While atmospheric pCO2 (CO2 partial pressure) predictions are mostly determined by the model forcings and the response of silicate weathering rate to pCO2 and temperature, multiple negative feedback processes and coupling of the C, O, P and S cycles are necessary for regulating pO2 while allowing \u03b413C changes of sufficient amplitude to match the record. \n \nThe results support a pO2 dependency of oxidative weathering of reduced carbon and sulfur, which raises early Paleozoic pO2 above the estimated requirement of Cambrian fauna and prevents unrealistically large \u03b434S variation. They do not support a strong anoxia dependency of the C:P burial ratio of marine organic matter (Van Cappellen and Ingall, 1994, 1996) because this dependency raises early Paleozoic \u03b413C and organic carbon burial rates too high. The dependency of terrestrial primary productivity on pO2 also contributes to oxygen regulation. An intermediate strength oxygen fire feedback on terrestrial biomass, which gives a pO2 upper limit of \u223c1.6PAL (present atmospheric level) or 30 volume percent, provides the best combined pO2 and \u03b413C predictions. \n \nSulfur cycle coupling contributes critically to lowering the Permo-Carboniferous pCO2 and temperature minimum. The results support an inverse dependency of pyrite sulfur burial on pO2 (for example, Berner and Canfield, 1989), which contributes to the shuttling of oxygen back and forth between carbonate carbon and gypsum sulfur. \n \nA pO2 dependency of photosynthetic carbon isotope fractionation (Berner and others, 2000; Beerling and others, 2002) is important for producing sufficient magnitude of \u03b413C variation. However, our results do not support an oxygen dependency of sulfur isotope fractionation in pyrite formation (Berner and others, 2000) because it generates unrealistically small variations in \u03b434S. \n \nIn the Early Paleozoic, COPSE predicts pO2=0.2\u20130.6PAL and pCO2>10PAL, with high oceanic [PO43-] and low [SO4=]. Land plant evolution caused a \u2018phase change\u2019 in the Earth system by increasing weathering rates and shifting some organic burial to land. This change resulted in a major drop in pCO2 to 3 to 4PAL and a rise in pO2 to \u223c1.5PAL in the Permo-Carboniferous, with temperatures below present, ocean variables nearer present concentrations, and PO4:NO3 regulated closer to Redfield ratio. A second O2 peak of similar or slightly greater magnitude appears in the mid-Cretaceous, before a descent towards PAL. Mesozoic CO2 is in the range 3 to 7PAL, descending toward PAL in the Cretaceous and Cenozoic.", "keyphrases": ["biogeochemical cycling", "cycling", "phanerozoic time", "atmosphere"]}
{"id": "10.3724/SP.J.1261.2015.00070", "title": "There was no \u201cGreat Bank of Guizhou\u201d in the Early Triassic in Guizhou Province South China", "abstract": "Abstract In the 1990s, some geologists named the Early Triassic isolated carbonate platform in the Luodian area of southern Guizhou Province in South China as the \u201cGreat Bank of Guizhou\u201d. During the past twenty years, this term \u201cGreat Bank of Guizhou\u201d was used in more than 300 articles in foreign countries. In the 1990s, the authors have studied the lithofacies palaeogeography of the Early and Middle Triassic in South China. In June 2014, we went to the Luodian area and studied the Early Triassic Bianyang section again. According to the geological data we acquired, in the Early Triassic of the Luodian area of southern Guizhou Province, there was only an isolated \u201cLuodian Carbonate Platform\u201d, while no bank existed, not to mention the \u201cGreat Bank of Guizhou\u201d. It is worth further discussion.", "keyphrases": ["great bank", "guizhou", "early triassic"]}
{"id": "10.1017/S0094837300019746", "title": "When are leaves good thermometers? A new case for Leaf Margin Analysis", "abstract": "Precise estimates of past temperatures are critical for understanding the evolution of organisms and the physical biosphere, and data from continental areas are an indispensable complement to the marine record of stable isotopes. Climate is considered to be a primary selective force on leaf morphology, and two widely used methods exist for estimating past mean annual temperatures from assemblages of fossil leaves. The first approach, Leaf Margin Analysis, is univariate, based on the positive correlation in modern forests between mean annual temperature and the proportion of species in a flora with untoothed leaf margins. The second approach, known as the Climate-Leaf Analysis Multivariate Program, is based on a modern data set that is multivariate. I argue here that the simpler, univariate approach will give paleotemperature estimates at least as precise as the multivariate method because (1) the temperature signal in the multivariate data set is dominated by the leaf-margin character; (2) the additional characters add minimal statistical precision and in practical use do not appear to improve the quality of the estimate; (3) the predictor samples in the univariate data set contain at least twice as many species as those in the multivariate data set; and (4) the presence of numerous sites in the multivariate data set that are both dry and extremely cold depresses temperature estimates for moist and nonfrigid paleofloras by about 2\u00b0C, unless the dry and cold sites are excluded from the predictor set. New data from Western Hemisphere forests are used to test the univariate and multivariate methods and to compare observed vs. predicted error distributions for temperature estimates as a function of species richness. Leaf Margin Analysis provides excellent estimates of mean annual temperature for nine floral samples. Estimated temperatures given by 16 floral subsamples are very close both to actual temperatures and to the estimates from the samples. Temperature estimates based on the multivariate data set for four of the subsamples were generally less accurate than the estimates from Leaf Margin Analysis. Leaf-margin data from 45 transect collections demonstrate that sampling of low-diversity floras at extremely local scales can result in biased leaf-margin percentages because species abundance patterns are uneven. For climate analysis, both modern and fossil floras should be sampled over an area sufficient to minimize this bias and to maximize recovered species richness within a given climate.", "keyphrases": ["leaf margin analysis", "annual temperature", "positive correlation"]}
{"id": "paleo.008011", "title": "The first Triassic vertebrate fossils from Myanmar: Pachypleurosaurs in a marine limestone", "abstract": "As ecosystems recovered from the end-Permian extinction, many new animal groups proliferated in the ensuing Triassic. Among these were the sauropterygians, reptiles that evolved from terrestrial ancestors and transitioned to a marine environment. The first sauropterygians were small, marine-adapted taxa such as pachypleurosaurs, which are known from Middle\u2013Late Triassic deposits, particularly in the Tethyan realm of Europe, and more recently from Lagerstatten in southwestern China. Here we report two pachypleurosaurs from Myanmar, the first Triassic vertebrate fossils from the country. These specimens demonstrate that their entombing rocks in northern Shan State, which have received less study than terrestrial sediments in southern Shan State and whose ages have long been uncertain, are Triassic. The specimens may be among the oldest pachypleurosaurs globally, potentially corroborating biogeographic scenarios that posit an eastern Tethyan origin for pachypleurosaurs, and raise the potential for future discoveries of well-preserved Triassic reptiles in Myanmar.", "keyphrases": ["triassic vertebrate fossil", "myanmar", "pachypleurosaur", "alpine triassic", "southern alps-transdanubian platform"]}
{"id": "paleo.009271", "title": "Integrated Analyses Resolve Conflicts over Squamate Reptile Phylogeny and Reveal Unexpected Placements for Fossil Taxa", "abstract": "Squamate reptiles (lizards and snakes) are a pivotal group whose relationships have become increasingly controversial. Squamates include >9000 species, making them the second largest group of terrestrial vertebrates. They are important medicinally and as model systems for ecological and evolutionary research. However, studies of squamate biology are hindered by uncertainty over their relationships, and some consider squamate phylogeny unresolved, given recent conflicts between molecular and morphological results. To resolve these conflicts, we expand existing morphological and molecular datasets for squamates (691 morphological characters and 46 genes, for 161 living and 49 fossil taxa, including a new set of 81 morphological characters and adding two genes from published studies) and perform integrated analyses. Our results resolve higher-level relationships as indicated by molecular analyses, and reveal hidden morphological support for the molecular hypothesis (but not vice-versa). Furthermore, we find that integrating molecular, morphological, and paleontological data leads to surprising placements for two major fossil clades (Mosasauria and Polyglyphanodontia). These results further demonstrate the importance of combining fossil and molecular information, and the potential problems of estimating the placement of fossil taxa from morphological data alone. Thus, our results caution against estimating fossil relationships without considering relevant molecular data, and against placing fossils into molecular trees (e.g. for dating analyses) without considering the possible impact of molecular data on their placement.", "keyphrases": ["fossil taxa", "snake", "ophidia", "recent common ancestor"]}
{"id": "10.7306/vj.17.2", "title": "Jurassic pebbles in the Cretaceous sandstones of the Bohemian Basin as a possible tool for reconstruction of the Late Jurassic and Late Cretaceous palaeogeography", "abstract": "A new find of pebbles of Jurassic silicites in the Coniacian sandstones of the Bohemian Cretaceous Basin in N Bohemia has permitted analysis of the stratigraphic extent of Jurassic sediments in the NW part of the Bohemian Massif. The studied silicites are dominated by the rhax microfacies, while bioclastic and oolitic microfacies are less common. The thickest section of Jurassic sediments in the NW part of the Bohemian Massif has been obtained from the Doubice borehole. It is represented by basal clastics overlain by a 70 m thick succession of silicite-free carbonate rocks which range in age from Callovian to Lower Kimmeridgian. These deposits are dominated by the bioclastic microfacies whereas the rhax and oolitic microfacies are missing. The studied silicite-bearing sequence is younger than the carbonate rocks in Doubice borehole and was deposited mostly in a deeper zone probably during the Late Kimmeridgian transgression, much like in the Upper Frankenalb in SE Germany. The extensive Jurassic basin in the Bohemian Massif was connected with the S\u00a0part of the Polish and German basins and \u2013 via the Hessian (Saxonian) Seaway \u2013 with the Jurassic basin in SE Germany. The Jurassic sediments were mostly eroded from the Bohemian Massif during the Early Cretaceous with the exception of small relics. The remnant of the Jurassic deposits preserved in the area of the West Sudetic Island supplied coarse debris during Late Cretaceous to the Bohemian Cretaceous Basin.", "keyphrases": ["pebble", "sandstone", "jurassic silicite", "bohemian cretaceous basin", "stratigraphical-and"]}
{"id": "10.1080/14772019.2018.1511387", "title": "The Interatheriinae (Mammalia, Notoungulata) of the Friasian sensu stricto and Mayoan (middle to late Miocene), and the fossils from Cerro Zeballos, Patagonia, Argentina", "abstract": "The middle to late Miocene Friasian sensu stricto, Colloncuran and Mayoan South American Land Mammal Ages (SALMAs) were established based on the mammals recovered from the R\u00edo Fr\u00edas, Coll\u00f3n Cur\u00e1 and R\u00edo Mayo formations, respectively (southern Argentina and Chile). Records of Interatheriinae (Notoungulata) from these sediments have been known since the first contributions of Ameghino and Roth, but most of this material has only been superficially revised or is almost unstudied. Based on these old collections and new interatheriine records from Cerro Zeballos (Chubut Province), we improve the diagnosis of Caenophilus tripartitus, describe new and peculiar characters for this taxon, consider Epipatriarchus bifidens as Protypotherium cf. colloncurensis, and propose Epipatriarchus as a junior synonym of Protypotherium. In turn, the holotype of Epipatriarchus innexus is here identified as the mesotheriid Trachytypotherium sp. Therefore, only two genera of Interatheriinae, Protypotherium and Caenophilus, are recognized in the Friasian sensu stricto and Mayoan. We identify Protypotherium cf. endiadys and a probable new species of Protypotherium for the Friasian sensu stricto, P. cf. colloncurensis and Caenophilus tripartitus for the Mayoan, and C. tripartitus, P. colloncurensis and P. cf. endiadys for Cerro Zeballos. An extended phylogenetic analysis is performed, including species from low latitudes and new data for P. colloncurensis and Caenophilus tripartitus, with the latter recovered as a sister taxon to Miocochilius federicoi. Both Protypotherium and Miocochilius are recovered as paraphyletic. The updated information we present provides a better knowledge of Interatheriinae for the middle to late Miocene of southern South America.", "keyphrases": ["interatheriinae", "notoungulata", "late miocene"]}
{"id": "10.1144/jgs2020-135", "title": "The Shibantan Lagerst\u00e4tte: insights into the Proterozoic\u2013Phanerozoic transition", "abstract": "The Shibantan Lagerst\u00e4tte (551\u2013543\u2005Ma) in the Yangtse Gorges area in South China is one of the best-known examples of terminal Ediacaran fossil assemblages preserved in marine carbonate rocks. Taxonomically dominated by benthic organisms, the Shibantan Lagerst\u00e4tte preserves various photoautotrophs, biomineralizing tubular fossils, Ediacara-type macrofossils (including rangeomorphs, arboreomorphs, erniettomorphs, palaeopascichnids, a possible dickinsoniomorph, the mobile bilaterian Yilingia and soft-bodied tubular fossils), abundant ichnofossils and a number of problematic and dubious fossils. Shibantan fossils provide intriguing insights into ecological interactions among mobile bilaterians, sessile benthic Ediacara-type organisms and microbial mats, thus offering important data to test various hypotheses accounting for the decline of the Ediacara biota and the concurrent expansion of bilaterian bioturbation and mobility across the Proterozoic\u2013Phanerozoic transition.", "keyphrases": ["shibantan lagerst\u00e4tte", "proterozoic\u2013phanerozoic transition", "mobility"]}
{"id": "paleo.005707", "title": "Ontogeny of the trilobite Elrathia kingii (Meek) and comparison of growth rates between Elrathia kingii and Aulacopleura koninckii (Barrande)", "abstract": "Trilobites offer almost unparalleled insight into the growth and development of fossil ecdysozoans. Here I use newly collected material of Elrathia kingii (Meek) to estimate growth rates and describe shape change over the ontogeny of E. kingii. Well\u2010preserved, articulated specimens from all post\u2010embryonic stages were collected from a 1.5 m interval of the upper Wheeler Formation (Miaolingian Series, Cambrian) in western Utah (USA), and size and landmark\u2010based shape data were digitized from photographs. Growth rates were estimated and compared with previously published data on the Silurian trilobite, Aulacopleura koninckii (Barrande). Like A. koninckii, the cephalic growth rate in E. kingii was constant and of similar magnitude to the minimum growth rate along the trunk, and growth rates in the trunk were lower during the holaspid (\u2018adult\u2019) period than during the meraspid (\u2018juvenile\u2019) period. However, body length at the onset of meraspis was smaller, the growth gradient along the trunk during meraspis was shallower, and the terminal number of thoracic tergites was smaller in E. kingii than in A. koninckii. Despite these differences, these two species had similar maximum body lengths, because higher overall growth rates in E. kingii compensated for other differences. The rate of cephalic shape change in E. kingii decreased at the transition from meraspis to holaspis, while the pygidium became more morphologically distinct from the thorax during holaspis. I also provide an emended diagnosis for E. kingii, descriptions of the ontogeny and ventral morphology, and evidence that E. kingii holaspids had an invariant number of tergites.", "keyphrases": ["elrathia", "growth rate", "ontogeny"]}
{"id": "10.1002/jmor.10565", "title": "Homologies of the longissimus, iliocostalis, and hypaxial muscles in the anterior presacral region of extant diapsida", "abstract": "Homologies of muscles of the m. longissimus and m. iliocostalis groups in the dorsal and cervical regions, as well as those of the subvertebral muscles and mm. intercostales externi that continue from the dorsal into the cervical regions, in extant Diapsida are proposed based on detailed dissections and published accounts of lepidosaurs, crocodylians, and birds. The morphology of tendons and innervation patterns suggest that the avian \u201cm. iliocostalis\u201d in the dorsal region include the homologs of both m. longissimus and m. iliocostalis in non\u2010avian diapsids. The conserved nature of the morphology of tendons in palaeognath birds also revealed that the avian mm. intertransversarii in the cervical region consist of muscles of the both m. longissimus and m. iliocostalis groups despite having been treated as a single series of muscles, and thus are not homologous with muscles of the same name in Lepidosauria or Crocodylia. The avian mm. inclusi that lie medial to mm. intertransversarii are homologous with mm. intercostales externi in Lepidosauria and mm. intercostales externi and m. scalenus combined in Crocodylia. Innervation patterns suggest that a muscle (\u201cm. iliocostalis capitis\u201d) connecting the atlas rib and occiput in Crocodylia includes contributions from the subvertebral layer and m. cucullaris complex, and possibly m. iliocostalis as well. The present findings may serve as a basis for revising the currently used avian nomenclature so that it will reflect homologies of muscles with their non\u2010avian counterparts. J. Morphol., 2007. \u00a9 2007 Wiley\u2010Liss, Inc.", "keyphrases": ["iliocostalis", "muscle", "extant diapsida"]}
{"id": "paleo.005655", "title": "Competition and constraint drove Cope's rule in the evolution of giant flying reptiles", "abstract": "The pterosaurs, Mesozoic flying reptiles, attained wingspans of more than 10 m that greatly exceed the largest birds and challenge our understanding of size limits in flying animals. Pterosaurs have been used to illustrate Cope\u2019s rule, the influential generalization that evolutionary lineages trend to increasingly large body sizes. However, unambiguous examples of Cope\u2019s rule operating on extended timescales in large clades remain elusive, and the phylogenetic pattern and possible drivers of pterosaur gigantism are uncertain. Here we show 70 million years of highly constrained early evolution, followed by almost 80 million years of sustained, multi-lineage body size increases in pterosaurs. These results are supported by maximum-likelihood modelling of a comprehensive new pterosaur data set. The transition between these macroevolutionary regimes is coincident with the Early Cretaceous adaptive radiation of birds, supporting controversial hypotheses of bird\u2013pterosaur competition, and suggesting that evolutionary competition can act as a macroevolutionary driver on extended geological timescales.", "keyphrases": ["wingspan", "body size", "competition", "late triassic", "small pterosaur"]}
{"id": "10.1002/ajb2.1163", "title": "Identifying fossil Myrtaceae leaves: the first described fossils of Syzygium from Australia.", "abstract": "PREMISE OF THE STUDY\nAlthough leaves of Myrtaceae are easily identified to family level, very few studies have convincingly identified fossil Myrtaceae leaves to living genera. We used a broadly comparative approach with a large data set of extant taxa to confidently assign the mummified remains of myrtaceous leaves from early Miocene sediments at Kiandra (New South Wales, Australia) to a living genus.\n\n\nMETHODS\nFossils were identified using a nearest living relative approach, against a database of 232 extant broadleaf rainforest species of Myrtaceae. Leaf cuticles were prepared from 106 species, sourced from herbarium specimens as well as some living individuals, and a further 127 records were assembled from the literature. A set of simple but phylogenetically informative cuticular characters were observed, described, and recorded under both scanning electron microscopy and standard light microscopy.\n\n\nKEY RESULTS\nA new fossil species of Syzygium Gaertn. is described from mummified remains found in early Miocene (21.5-21.7 Ma) sediments. The fossil taxon is here named Syzygium christophelii sp. nov., in honor of the late Australian paleobotanist David Christophel.\n\n\nCONCLUSIONS\nThese fossils represent some of the most confidently described Myrtaceae leaf fossils published to date and are the first and oldest described fossil record of Syzygium from Australia. While several fossil parataxa have been illustrated from New Zealand, and several fossil species of Syzygium have previously been proposed in the literature, many of these fossils lack characters for a confident diagnosis.", "keyphrases": ["fossil myrtaceae", "syzygium", "australia"]}
{"id": "paleo.006928", "title": "The transition between Carcharocles chubutensis and Carcharocles megalodon (Otodontidae, Chondrichthyes): lateral cusplet loss through time", "abstract": "ABSTRACT The teeth of two megatooth macro-predatory shark species (Carcharocles chubutensis and Carcharocles megalodon; Otodontidae, Chondrichthyes) occur within the Miocene Chesapeake Group of Maryland, U.S.A. Definitive separation between all the teeth of Carcharocles chubutensis and Carcharocles megalodon is impossible because a complex mosaic evolutionary continuum characterizes this transformation, particularly in the loss of lateral cusplets. The cuspleted and uncuspleted teeth of Carcharocles spp. are designated as chronomorphs because there is wide overlap between them both morphologically and chronologically. In the lower Miocene Beds (Shattuck Zones) 2\u20139 of the Calvert Formation (representing approximately 3.2 million years, 20.2\u201317 Ma, Burdigalian) both cuspleted and uncuspleted teeth are present, but cuspleted teeth predominate, constituting approximately 87% of the Carcharocles spp. teeth represented in our sample. However, in the middle Miocene Beds 10\u201316A of the Calvert Formation (representing approximately 2.4 million years, 16.4\u201314 Ma, Langhian), there is a steady increase in the proportion of uncuspleted Carcharocles teeth. In the upper Miocene Beds 21\u201324 of the St. Marys Formation (representing approximately 2.8 million years, 10.4\u20137.6 Ma, Tortonian), lateral cusplets are nearly absent in Carcharocles teeth from our study area, with only a single specimen bearing lateral cusplets. The dental transition between Carcharocles chubutensis and Carcharocles megalodon occurs within the Miocene Chesapeake Group. Although this study helps to elucidate the timing of lateral cusplet loss in Carcharocles locally, the rationale for this prolonged evolutionary transition remains unclear.", "keyphrases": ["carcharocles megalodon", "otodontidae", "chondrichthyes", "shark"]}
{"id": "10.1017/S0016756813000587", "title": "Belgian substages as a basis for an international chronostratigraphic division of the Tournaisian and Vis\u00e9an", "abstract": "Abstract The Tournaisian and Vis\u00e9an were formerly considered as series and in Belgium were divided into two (Hastarian and Ivorian) and three stages (Moliniacian, Livian and Warnantian), which are now considered as substages. The Belgian substages are based on conodonts and foraminifers, and incidentally on rugose corals, and are described here. Their boundaries, biostratigraphy and sequence stratigraphy are well detailed and clearly defined. The base of the Hastarian (lower Tournaisian) corresponds to the base of the Tournaisian (base of Carboniferous); the base of the Ivorian (upper Tournaisian) corresponds to the appearance of the conodont Polygnathus communis carina, a little above the last Siphonodella; the base of the Moliniacian (lower Vis\u00e9an) corresponds to the base of the Vis\u00e9an stage defined by the first occurrence of the foraminifer Eoparastaffella simplex; the Livian (middle Vis\u00e9an) corresponds to the foraminiferal MFZ12 Zone and is marked by the appearance of Koskinotextularia and Pojarkovella nibelis; the base of the Warnantian (upper Vis\u00e9an) is marked by the appearance of Neoarchaediscus, Vissariotaxis, Planospirodiscus, and Palaeotextularia with a bilaminar wall, the index taxa of the MFZ13-Neoarchaediscus Zone. The up-to-date chronostratigraphic subdivision of the Tournaisian and Vis\u00e9an is not limited to Belgium and the surrounding areas. It can be applied through Eurasia as far as South China. The Belgian units could therefore be the basis for a future international division of the Tournaisian into two parts (Hastarian and Ivorian) and of the Vis\u00e9an into three parts (Moliniacian, Livian and Warnantian), corresponding to time intervals of c. 5\u20138 Ma.", "keyphrases": ["substage", "division", "tournaisian"]}
{"id": "10.1098/rspb.2009.1845", "title": "Mesozoic marine tetrapod diversity: mass extinctions and temporal heterogeneity in geological megabiases affecting vertebrates", "abstract": "The fossil record is our only direct means for evaluating shifts in biodiversity through Earth's history. However, analyses of fossil marine invertebrates have demonstrated that geological megabiases profoundly influence fossil preservation and discovery, obscuring true diversity signals. Comparable studies of vertebrate palaeodiversity patterns remain in their infancy. A new species-level dataset of Mesozoic marine tetrapod occurrences was compared with a proxy for temporal variation in the volume and facies diversity of fossiliferous rock (number of marine fossiliferous formations: FMF). A strong correlation between taxic diversity and FMF is present during the Cretaceous. Weak or no correlation of Jurassic data suggests a qualitatively different sampling regime resulting from five apparent peaks in Triassic\u2013Jurassic diversity. These correspond to a small number of European formations that have been the subject of intensive collecting, and represent \u2018Lagerst\u00e4tten effects\u2019. Consideration of sampling biases allows re-evaluation of proposed mass extinction events. Marine tetrapod diversity declined during the Carnian or Norian. However, the proposed end-Triassic extinction event cannot be recognized with confidence. Some evidence supports an extinction event near the Jurassic/Cretaceous boundary, but the proposed end-Cenomanian extinction is probably an artefact of poor sampling. Marine tetrapod diversity underwent a long-term decline prior to the Cretaceous\u2013Palaeogene extinction.", "keyphrases": ["marine tetrapod diversity", "geological megabiase", "sampling", "mesozoic"]}
{"id": "paleo.009320", "title": "Correlation between investment in sexual traits and valve sexual dimorphism in Cyprideis species (Ostracoda)", "abstract": "Assessing the long-term macroevolutionary consequences of sexual selection has been hampered by the difficulty of studying this process in the fossil record. Cytheroid ostracodes offer an excellent system to explore sexual selection in the fossil record because their readily fossilized carapaces are sexually dimorphic. Specifically, males are relatively more elongate than females in this superfamily. This sexual shape difference is thought to arise so that males carapaces can accommodate their very large copulatory apparatus, which can account for up to one-third of body volume. Here we test this widely held explanation for sexual dimorphism in cytheroid ostracodes by correlating investment in male genitalia, a trait in which sexual selection is seen as the main evolutionary driver, with sexual dimorphism of carapace in the genus Cyprideis. We analyzed specimens collected in the field (C. salebrosa, USA; C. torosa, UK) and from collections of the National Museum of Natural History, Washington, DC (C. mexicana). We digitized valve outlines in lateral view to obtain measures of size (valve area) and shape (elongation, measured as length to height ratio), and obtained several dimensions from two components of the hemipenis: the muscular basal capsule, which functions as a sperm pump, and the section that includes the intromittent organ (terminal extension). In addition to the assessment of this primary sexual trait, we also quantified two dimensions of the male secondary sexual trait\u2014where the transformed right walking leg functions as a clasping organ during mating. We also measured linear dimensions from four limbs as indicators of overall (soft-part) body size, and assessed allometry of the soft anatomy. We observed significant correlations in males between valve size, but not elongation, and distinct structural parts of the hemipenis, even after accounting for their shared correlation with overall body size. We also found weak but significant positive correlation between valve elongation and the degree of sexual dimorphism of the walking leg, but only in C. torosa. The correlation between the hemipenis parts, especially basal capsule size and male valve size dimorphism suggests that sexual selection on sperm size, quantity, and/or efficiency of transfer may drive sexual size dimorphism in these species, although we cannot exclude other aspects of sexual and natural selection.", "keyphrases": ["investment", "sexual trait", "dimorphism", "indicator"]}
{"id": "10.1073/pnas.1216750110", "title": "Macropredatory ichthyosaur from the Middle Triassic and the origin of modern trophic networks", "abstract": "The biotic recovery from Earth\u2019s most severe extinction event at the Permian-Triassic boundary largely reestablished the preextinction structure of marine trophic networks, with marine reptiles assuming the predator roles. However, the highest trophic level of today's marine ecosystems, i.e., macropredatory tetrapods that forage on prey of similar size to their own, was thus far lacking in the Paleozoic and early Mesozoic. Here we report a top-tier tetrapod predator, a very large (>8.6 m) ichthyosaur from the early Middle Triassic (244 Ma), of Nevada. This ichthyosaur had a massive skull and large labiolingually flattened teeth with two cutting edges indicative of a macropredatory feeding style. Its presence documents the rapid evolution of modern marine ecosystems in the Triassic where the same level of complexity as observed in today\u2019s marine ecosystems is reached within 8 My after the Permian-Triassic mass extinction and within 4 My of the time reptiles first invaded the sea. This find also indicates that the biotic recovery in the marine realm may have occurred faster compared with terrestrial ecosystems, where the first apex predators may not have evolved before the Carnian.", "keyphrases": ["ichthyosaur", "middle triassic", "trophic network", "biotic recovery", "mass extinction"]}
{"id": "10.5194/cp-11-1507-2015", "title": "Stratification of surface waters during the last glacial millennial climatic events: a key factor in subsurface and deep-water mass dynamics", "abstract": "Abstract. The last glacial period was punctuated by abrupt climatic events with extrema known as Heinrich and Dansgaard\u2013Oeschger events. These millennial events have been the subject of many paleoreconstructions and model experiments in the past decades, but yet the hydrological processes involved remain elusive. In the present work, high-resolution analyses were conducted on the 12\u201342 ka BP section of core MD99-2281 retrieved southwest of the Faeroe Islands, and combined with analyses conducted in two previous studies (Zumaque et al., 2012; Caulle et al., 2013). Such a multiproxy approach, coupling micropaleontological, geochemical and sedimentological analyses, allows us to track surface, subsurface, and deep hydrological processes occurring during these rapid climatic changes. Records indicate that the coldest episodes of the studied period (Greenland stadials and Heinrich stadials) were characterized by a strong stratification of surface waters. This surface stratification seems to have played a key role in the dynamics of subsurface and deep-water masses. Indeed, periods of high surface stratification are marked by a coupling of subsurface and deep circulations which sharply weaken at the beginning of stadials, while surface conditions progressively deteriorate throughout these cold episodes; conversely, periods of decreasing surface stratification (Greenland interstadials) are characterized by a coupling of surface and deep hydrological processes, with progressively milder surface conditions and gradual intensification of the deep circulation, while the vigor of the subsurface northward Atlantic flow remains constantly high. Our results also reveal different and atypical hydrological signatures during Heinrich stadials (HSs): while HS1 and HS4 exhibit a \"usual\" scheme with reduced overturning circulation, a relatively active North Atlantic circulation seems to have prevailed during HS2, and HS3 seems to have experienced a re-intensification of this circulation during the middle of the event. Our findings thus bring valuable information to better understand hydrological processes occurring in a key area during the abrupt climatic shifts of the last glacial period.", "keyphrases": ["surface water", "climatic event", "stratification"]}
{"id": "10.5194/cp-10-1421-2014", "title": "Warming, euxinia and sea level rise during the Paleocene\u2013Eocene Thermal Maximum on the Gulf Coastal Plain: implications for ocean oxygenation and nutrient cycling", "abstract": "Abstract. The Paleocene\u2013Eocene Thermal Maximum (PETM, ~ 56 Ma) was a ~ 200 kyr episode of global warming, associated with massive injections of 13C-depleted carbon into the ocean\u2013atmosphere system. Although climate change during the PETM is relatively well constrained, effects on marine oxygen concentrations and nutrient cycling remain largely unclear. We identify the PETM in a sediment core from the US margin of the Gulf of Mexico. Biomarker-based paleotemperature proxies (methylation of branched tetraether\u2013cyclization of branched tetraether (MBT\u2013CBT) and TEX86) indicate that continental air and sea surface temperatures warmed from 27\u201329 to ~ 35 \u00b0C, although variations in the relative abundances of terrestrial and marine biomarkers may have influenced these estimates. Vegetation changes, as recorded from pollen assemblages, support this warming. The PETM is bracketed by two unconformities. It overlies Paleocene silt- and mudstones and is rich in angular (thus in situ produced; autochthonous) glauconite grains, which indicate sedimentary condensation. A drop in the relative abundance of terrestrial organic matter and changes in the dinoflagellate cyst assemblages suggest that rising sea level shifted the deposition of terrigenous material landward. This is consistent with previous findings of eustatic sea level rise during the PETM. Regionally, the attribution of the glauconite-rich unit to the PETM implicates the dating of a primate fossil, argued to represent the oldest North American specimen on record. The biomarker isorenieratene within the PETM indicates that euxinic photic zone conditions developed, likely seasonally, along the Gulf Coastal Plain. A global data compilation indicates that O2 concentrations dropped in all ocean basins in response to warming, hydrological change, and carbon cycle feedbacks. This culminated in (seasonal) anoxia along many continental margins, analogous to modern trends. Seafloor deoxygenation and widespread (seasonal) anoxia likely caused phosphorus regeneration from suboxic and anoxic sediments. We argue that this fueled shelf eutrophication, as widely recorded from microfossil studies, increasing organic carbon burial along many continental margins as a negative feedback to carbon input and global warming. If properly quantified with future work, the PETM offers the opportunity to assess the biogeochemical effects of enhanced phosphorus regeneration, as well as the timescales on which this feedback operates in view of modern and future ocean deoxygenation.", "keyphrases": ["sea level rise", "paleocene\u2013eocene thermal maximum", "gulf coastal plain", "ocean deoxygenation"]}
{"id": "paleo.011676", "title": "Dynamic and synchronous changes in metazoan body size during the Cambrian Explosion", "abstract": "Many aspects of the drivers for, and evolutionary dynamics of, the Cambrian Explosion are poorly understood. Here we quantify high-resolution changes in species body size in major metazoan groups on the Siberian Platform during the early Cambrian (ca. 540\u2013510 Million years ago (Ma)). Archaeocyath sponges, hyolith lophophorates, and helcionelloid mollusc species show dynamic and synchronous trends over million-year timescales, with peaks in body size during the latest Tommotian/early Atbadanian and late Atdabanian/early Botoman, and notably small body sizes in the middle Atdabanian and after the Sinsk anoxic extinction event, starting ca. 513 Ma. These intervals of body size changes are also mirrored in individual species and correlate positively with increased rates of origination and broadly with total species diversity. Calcitic brachiopods (rhynchonelliformeans), however, show a general increase in body size following the increase in species diversity through this interval: phosphatic brachiopods (linguliformeans) show a body size decrease that negatively correlates with diversity. Both brachiopod groups show a rapid recovery at the Sinsk Event. The synchronous changes in these metrics in archaeocyath, hyoliths and helcionelloids suggest the operation of external drivers through the early Cambrian, such as episodic changes in oxygenation or productivity. But the trends shown by brachiopods suggests a differing physiological response. Together, these dynamics created both the distinct evolutionary record of metazoan groups during the Cambrian Explosion and determined the nature of its termination.", "keyphrases": ["synchronous change", "cambrian explosion", "archaeocyath"]}
{"id": "paleo.004515", "title": "Late Mesoproterozoic \u2013 early Neoproterozoic organic\u2010walled microfossils from the Madhubani Group of the Ganga Valley, northern India", "abstract": "The age of the sedimentary basement of the Ganga Valley in northern India, which is represented by the entirely subsurface Ganga Supergroup, is key for addressing issues related to the tectonic history of the Himalaya. However, the stratigraphic correlations between the Ganga Supergroup in the Ganga Valley, the Vindhyan Supergroup in cratonic India to the south, and Proterozoic successions in the Lesser Himalaya to the north have long been a matter of controversy. This is largely because of the poor age constraint of the Madhubani Group of the upper Ganga Supergroup, which has been variously interpreted as Proterozoic, lower Palaeozoic, or even Mesozoic. To address this issue, we used a low manipulation maceration technique to extract organic\u2010walled microfossils from the Ujhani and Tilhar formations of the lower Madhubani Group. Our study recovered a total of 24 taxa, including Devisphaera corallis gen. et sp. nov. The co\u2010occurrence of Trachyhystrichosphaera aimika, Caudosphaera expansa and Annulusia annulata in the lower Madhubani Group indicates a late Mesoproterozoic to early Neoproterozoic age. Thus, the biostratigraphical data suggest a >300 myr depositional gap between the Madhubani Group and the immediately underlying Bahraich Group, which has been independently constrained to be upper Palaeoproterozoic to lower Mesoproterozoic in age. Therefore, the first\u2010order stratigraphic architecture, with a Palaeoproterozoic\u2013Mesoproterozoic succession unconformably overlain by a Mesoproterozoic\u2013Neoproterozoic succession, is closely similar throughout the Vindhyan Basin, Ganga Valley and Lesser Himalaya, suggesting a shared sedimentary and tectonic history among them.", "keyphrases": ["mesoproterozoic", "organic\u2010walled microfossil", "microfossil"]}
{"id": "paleo.004507", "title": "First record of non-mineralized cephalopod jaws and arm hooks from the latest Cretaceous of Eurytania, Greece", "abstract": "Due to the lower fossilization potential of chitin, non-mineralized cephalopod jaws and arm hooks are much more rarely preserved as fossils than the calcitic lower jaws of ammonites or the calcitized jaw apparatuses of nautilids. Here, we report such non-mineralized fossil jaws and arm hooks from pelagic marly limestones of continental Greece. Two of the specimens lie on the same slab and are assigned to the Ammonitina; they represent upper jaws of the aptychus type, which is corroborated by finds of aptychi. Additionally, one intermediate type and one anaptychus type are documented here. The morphology of all ammonite jaws suggest a desmoceratoid affinity. The other jaws are identified as coleoid jaws. They share the overall U-shape and proportions of the outer and inner lamellae with Jurassic lower jaws of Trachyteuthis (Teudopseina). We also document the first belemnoid arm hooks from the Tethyan Maastrichtian. The fossils described here document the presence of a typical Mesozoic cephalopod assemblage until the end of the Cretaceous in the eastern Tethys.", "keyphrases": ["non-mineralized cephalopod jaw", "arm hook", "greece"]}
{"id": "paleo.005849", "title": "Protracted growth impedes the detection of sexual dimorphism in non\u2010avian dinosaurs", "abstract": "Evidence for sexual dimorphism is extremely limited in the non\u2010avian dinosaurs despite their high diversity and disparity, and despite the fact that dimorphism is very common in vertebrate lineages of all kinds. Using body\u2010size data from both Alligator mississippiensis and Rhea americana, which phylogenetically bracket the dinosaurs, we demonstrate that even when there is strong dimorphism in a species, random sampling of populations of individuals characterized by sustained periods of growth (as in the alligator and most dinosaurs) can result in the loss of this signal. Dimorphism may be common in fossil taxa but very hard to detect without ontogenetic age control and large sample sizes, both of which are hampered by the limitations of the fossil record. Signal detection may be further hindered by Type III survivorship, whereby increased mortality among the young favours the likelihood that they will be sampled (unless predation or taphonomic bias against small size acts against this). These, and other considerations relating to behaviour and ecology, provide powerful reasons to suggest that sexual dimorphism in dinosaurs may be very difficult to detect in almost all currently available samples. Similar issues are likely also to be applicable to many fossil reptiles, or animals more generally.", "keyphrases": ["detection", "sexual dimorphism", "non\u2010avian dinosaur", "fossil taxa", "large sample size"]}
{"id": "paleo.007440", "title": "Eggshell Porosity Provides Insight on Evolution of Nesting in Dinosaurs", "abstract": "Knowledge about the types of nests built by dinosaurs can provide insight into the evolution of nesting and reproductive behaviors among archosaurs. However, the low preservation potential of their nesting materials and nesting structures means that most information can only be gleaned indirectly through comparison with extant archosaurs. Two general nest types are recognized among living archosaurs: 1) covered nests, in which eggs are incubated while fully covered by nesting material (as in crocodylians and megapodes), and 2) open nests, in which eggs are exposed in the nest and brooded (as in most birds). Previously, dinosaur nest types had been inferred by estimating the water vapor conductance (i.e., diffusive capacity) of their eggs, based on the premise that high conductance corresponds to covered nests and low conductance to open nests. However, a lack of statistical rigor and inconsistencies in this method render its application problematic and its validity questionable. As an alternative we propose a statistically rigorous approach to infer nest type based on large datasets of eggshell porosity and egg mass compiled for over 120 extant archosaur species and 29 archosaur extinct taxa/ootaxa. The presence of a strong correlation between eggshell porosity and nest type among extant archosaurs indicates that eggshell porosity can be used as a proxy for nest type, and thus discriminant analyses can help predict nest type in extinct taxa. Our results suggest that: 1) covered nests are likely the primitive condition for dinosaurs (and probably archosaurs), and 2) open nests first evolved among non-avian theropods more derived than Lourinhanosaurus and were likely widespread in non-avian maniraptorans, well before the appearance of birds. Although taphonomic evidence suggests that basal open nesters (i.e., oviraptorosaurs and troodontids) were potentially the first dinosaurs to brood their clutches, they still partially buried their eggs in sediment. Open nests with fully exposed eggs only became widespread among Euornithes. A potential co-evolution of open nests and brooding behavior among maniraptorans may have freed theropods from the ground-based restrictions inherent to covered nests and allowed the exploitation of alternate nesting locations. These changes in nesting styles and behaviors thus may have played a role in the evolutionary success of maniraptorans (including birds).", "keyphrases": ["nesting", "behavior", "egg", "crocodylian", "eggshell porosity"]}
{"id": "paleo.002293", "title": "The dentition of Carodnia vieirai (Mammalia: Xenungulata): enamel microstructure and mastication pattern", "abstract": "Post canine teeth of the Paleogene Carodnia from Brazil were investigated in regard to the enamel microstructure and the mastication pattern. The enamel is entirely prismatic, and the interprismatic matrix (IPM) is oriented parallel to the prisms, which consist of Boyde's patterns 1 and 2. The prominent vertical Hunter-Schreger-bands (HSB) are restricted to an outer zone, whereas the inner zone is formed by transverse but irregular HSB. Such a combination is very rare in mammalian teeth, but shows some similarities to the schmelzmuster of specific perissodactyls, where it evolved independently. Significant differences to Astrapotheria were found. The mastication pattern can be derived from the orientation of the wear facets on the transverse lophs. In stages of moderate tooth wear, the lophs have one-sided planar facets that are inclined in the upper and lower teeth antagonistically. Enamel crests on the leading sides cut like scissors. Subsequently, the antagonistic shear-cutting crests of the lophs pass each other and compress the food items until central occlusion. Thus, the jaw movement during phase I is predominantly mesial with a distinct inclination upwards.\nNo traces indicate a phase II of the power stroke. Neither the enamel nor the widelydistributed mastication pattern offer convincing arguments to support any of proposed phylogenetic relationship of Carodnia. The rare schmelzmuster contributes to the diversity of enamel microstructures in South American ungulates.", "keyphrases": ["enamel microstructure", "mastication pattern", "phylogenetic relationship"]}
{"id": "paleo.006441", "title": "THE HEAD AND NECK MUSCLES ASSOCIATED WITH FEEDING IN SPHENODON (REPTILIA: LEPIDOSAURIA: RHYNCHOCEPHALIA)", "abstract": "Feeding in Sphenodon, the tuatara of New Zealand, is of interest for several reasons. First, the modern animal is threatened by extinction, and some populations are in competition for food with Pacific rats. Second, Sphenodon demonstrates a feeding apparatus that is unique to living amniotes: an enlarged palatine tooth row, acrodont dentition, enlarged incisor-like teeth on the premaxilla, a posterior extension of the dentary and an elongate articular surtace that permits prooral shearing. Third, Sphenodon has a skull with two complete lateral temporal bars and is therefore structurally analogous to the configuration hypothesised for the ancestral diapsid reptile. Furthermore, the fossil relatives of Sphenodon demonstrate considerable variation in terms of feeding apparatus and skull shape. Lastly, as Sphenodon is the only extant rhynchocephalian it represents a potentially useful reference taxon for both muscle reconstruction in extinct reptile taxa and determination of muscle homology in extant taxa.\nHere we provide an up-to-date consensus view of osteology and musculature in Sphenodon that is relevant to feeding. Discrepancies within previous descriptions are evaluated and synthesised with new observations. This paper displays the complex muscle arrangement using a range of different imaging techniques and a variety of different angles. This includes photographs, illustrations, schematic diagrams, and microcomputed tomography (micro-CT) slice images.", "keyphrases": ["sphenodon", "rhynchocephalian", "muscle arrangement"]}
{"id": "paleo.005117", "title": "Differential influences of allometry, phylogeny and environment on the rostral shape diversity of extinct South American notoungulates", "abstract": "Understanding the mechanisms responsible for phenotypic diversification, and the associated underlying constraints and ecological factors represents a central issue in evolutionary biology. Mammals present a wide variety of sizes and shapes, and are characterized by a high number of morphological convergences that are hypothesized to reflect similar environmental pressures. Extinct South American notoungulates evolved in isolation from northern mammalian faunas in highly disparate environments. They present a wide array of skeletal phenotypes and convergences, such as ever-growing dentition. Here, we focused on the origins of the rostral diversity of notoungulates by quantifying the shape of 26 genera using three-dimensional geometric morphometric analysis. We tested the influence of allometry and phylogeny on rostral shape and evaluated rates of evolutionary change in the different clades. We found strong allometric and phylogenetic signals concerning the rostral shape of notoungulates. Despite convergent forms, we observed a diffuse diversification of rostral shape, with no significant evidence of influence by large-scaled environmental variation. This contrasts with the increase in dental crown height that occurred in four late-diverging families in response to similar environmental pressures. These results illustrate the importance of considering both biological components and evolutionary rates to better understand some aspects of phenotypic diversity.", "keyphrases": ["influence", "allometry", "notoungulate"]}
{"id": "10.1093/nsr/nwz194", "title": "Finding a home for hyoliths", "abstract": "Manyof the animal lineages that aroseduring theCambrian evolutionary radiation, 540 million years ago, are difficult to relate to living taxa. Constraining the phylogenetic position of these highly disparate taxa allows their idiosyncratic morphologies to illuminate the stepwise establishment of modern body plans [1\u20133]. Hyoliths are one such lineage; their operculate conical shells are common Palaeozoic fossils. Hyoliths have recently been identified as brachiopods based on the description of an attachment stalk [4] and a tentaculate feeding apparatus [5]. Liu et al. [6] present an alternative view, interpreting the putative pedicle as a damaged shell apex, and questioning whether the feeding apparatus ought to be termed a lophophore.", "keyphrases": ["hyolith", "phylogenetic position", "brachiopod"]}
{"id": "10.1098/rspb.2013.3122", "title": "Metabolic dominance of bivalves predates brachiopod diversity decline by more than 150 million years", "abstract": "Brachiopods and bivalves feed in similar ways and have occupied the same environments through geological time, but brachiopods were far more diverse and abundant in the Palaeozoic whereas bivalves dominate the post-Palaeozoic, suggesting a transition in ecological dominance 250 Ma. However, diversity and abundance data alone may not adequately describe key changes in ecosystem function, such as metabolic activity. Here, we use newly compiled body size data for 6066 genera of bivalves and brachiopods to calculate metabolic rates and revisit this question from the perspective of energy use, finding that bivalves already accounted for a larger share of metabolic activity in Palaeozoic oceans. We also find that the metabolic activity of bivalves has increased by more than two orders of magnitude over this interval, whereas brachiopod metabolic activity has declined by more than 50%. Consequently, the increase in bivalve energy metabolism must have occurred via the acquisition of new food resources rather than through the displacement of brachiopods. The canonical view of a mid-Phanerozoic transition from brachiopod to bivalve dominance results from a focus on taxonomic diversity and numerical abundance as measures of ecological importance. From a metabolic perspective, the oceans have always belonged to the clams.", "keyphrases": ["dominance", "bivalve", "brachiopod", "metabolic rate"]}
{"id": "10.1371/journal.pone.0109210", "title": "Bayesian Analysis Using a Simple Likelihood Model Outperforms Parsimony for Estimation of Phylogeny from Discrete Morphological Data", "abstract": "Despite the introduction of likelihood-based methods for estimating phylogenetic trees from phenotypic data, parsimony remains the most widely-used optimality criterion for building trees from discrete morphological data. However, it has been known for decades that there are regions of solution space in which parsimony is a poor estimator of tree topology. Numerous software implementations of likelihood-based models for the estimation of phylogeny from discrete morphological data exist, especially for the Mk model of discrete character evolution. Here we explore the efficacy of Bayesian estimation of phylogeny, using the Mk model, under conditions that are commonly encountered in paleontological studies. Using simulated data, we describe the relative performances of parsimony and the Mk model under a range of realistic conditions that include common scenarios of missing data and rate heterogeneity.", "keyphrases": ["phylogeny", "efficacy", "mkv model"]}
{"id": "paleo.006692", "title": "A NEW PTEROSAUR FROM THE LIAONING PROVINCE OF CHINA, THE PHYLOGENY OF THE PTERODACTYLOIDEA, AND CONVERGENCE IN THEIR CERVICAL VERTEBRAE", "abstract": "Abstract:\u2002 The largest known flying organisms are the azhdarchid pterosaurs, a pterodactyloid clade previously diagnosed by the characters of their extremely elongate middle\u2010series cervical vertebrae. The named species of the Azhdarchidae are from the Late Cretaceous. However, isolated mid\u2010cervical vertebrae with similar dimensions and characters have been referred to this group that date back to the Late Jurassic, implying an almost 60 million year gap in the fossil record of this group and an unrecorded radiation in the Jurassic of all the major clades of the Pterodactyloidea. A new pterosaur from the Early Cretaceous of Liaoning Province of China, Elanodactylus prolatus gen. et sp. nov., is described with mid\u2010cervical vertebrae that bear these azhdarchid characters but has other postcranial material that are distinct from the members of this group. Phylogenetic analysis of the new species and the Pterodactyloidea places it with the Late Jurassic vertebrae in the Late Jurassic\u2013Early Cretaceous Ctenochasmatidae and reveals that the characters of the elongate azhdarchid vertebrae appeared independently in both groups. These results are realized though the large taxon sampling in the analysis demonstrating that the homoplastic character states present in these two taxa were acquired in a different order in their respective lineages. Some of these homoplastic characters were previously thought to appear once in the history of pterosaurs and may be correlated to the extension of the neck regions in both groups. Because the homoplastic character states in the Azhdarchidae and Ctenochasmatidae are limited to the mid\u2010cervical vertebrae, these states are termed convergent based on a definition of the term in a phylogenetic context. A number of novel results from the analysis presented produce a reorganization in the different species and taxa of the Pterodactyloidea.", "keyphrases": ["pterosaur", "china", "pterodactyloidea", "phylogenetic analysis", "ctenochasmatidae"]}
{"id": "paleo.000998", "title": "Exceptionally well-preserved early Eocene fossil reveals cranial and vertebral features of a stem group roller (Aves: Coraciiformes)", "abstract": "Three-dimensionally preserved skulls of small Paleogene land birds are very rare. Here, we describe a cranium and associated partial postcranial remains of an early Eocene stem group roller (Aves: Coraciiformes) from the London Clay of the Isle of Sheppey (England). The fossil shows features of the skull and vertebral column in great detail. It is distinguished from extant Coraciidae and Brachypteraciidae in several presumably plesiomorphic characteristics, which are likely to reflect differences in diet and/or foraging strategy between Eocene and extant rollers. Preserved stomach contents in other early Eocene fossils indicate that fruits were a regular part of the diet of stem group rollers. The extant Coraciidae and Brachypteraciidae, by contrast, almost exclusively feed on larger-sized invertebrates and small vertebrates, which are usually dispatched by beating before being swallowed. Stronger biting forces as well as the characteristic prey manipulation behavior of extant rollers may account for some of the observed differences in the cranial and vertebral morphology of the fossil and extant taxa, but the exact functional correlations remain elusive. We furthermore identify a previously undescribed cranial feature of rollers: a very large foramen for the ramus occipitalis of the arteria ophthalmica externa, which is of unknown functional significance and constitutes a potentially promising research target for future studies.", "keyphrases": ["eocene fossil", "stem group roller", "coraciiformes", "skull", "london clay"]}
{"id": "10.1177/0309133306071146", "title": "Late Quaternary paleoenvironmental changes in East Africa: a review of multiproxy evidence from palynology, lake sediments, and associated records", "abstract": "This paper presents an overview of paleoenvironmental changes in East Africa during the late Quaternary based on evidence from pollen, diatoms, microscopic charcoal, and lake level records and associated proxies. The paleoenvironmental records derived from different proxies complement each other to provide a more accurate and complete assessment of the paleoenvironmental changes in East Africa. The records show that the period prior to c. 42,000 14C yr BP was characterized by warm climatic conditions similar to the present. This was followed by a change to cold dry conditions from 42,000 to 30,000 14C yr BP, and cold and moist conditions from 30,000 to 21,000 14C yr BP. Temperatures during the latter period leading to the Last Glacial Maximum (LGM) were probably 2 to 4.1\u00b0C lower than the present. Between c. 21,000 and 12,500 14C yr BP East Africa's environment was generally cool, punctuated by two significant episodes of prolonged desiccation. Warm and moist conditions punctuated by rapid climatic changes prevailed in the region during the deglacial and middle Holocene period. Ice core records document two significant and abrupt drought events in the region, one at 8300 14C yr BP and the other at 5200 14C yr BP. The onset of a longer and more extensive desiccation period commencing 4000 14C yr BP was registered in nearly all sites. The climate of East Africa was generally drier than present during the Medieval Warm Period (MWP) while fairly wet conditions prevailed during the Little Ice Age (LIA) interrupted by three episodes of aridity, more severe than those of more recent times. Whereas this review advances our understanding of climate and vegetational changes in East Africa beyond the Last Glacial Maximum, it also highlights limitations of the paradigms that explain the forcing mechanisms behind the changes. However, unequivocal interpretation of the multiproxy data from East Africa with respect to paleoenvironmental changes becomes extremely complex and challenging especially when the anthropogenic input is considered.", "keyphrases": ["paleoenvironmental change", "east africa", "review"]}
{"id": "10.1029/2004pa001071", "title": "A Pliocene\u2010Pleistocene stack of 57 globally distributed benthic \u03b418O records", "abstract": "[1]\u00a0We present a 5.3-Myr stack (the \u201cLR04\u201d stack) of benthic \u03b418O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm. This is the first benthic \u03b418O stack composed of more than three records to extend beyond 850 ka, and we use its improved signal quality to identify 24 new marine isotope stages in the early Pliocene. We also present a new LR04 age model for the Pliocene-Pleistocene derived from tuning the \u03b418O stack to a simple ice model based on 21 June insolation at 65\u00b0N. Stacked sedimentation rates provide additional age model constraints to prevent overtuning. Despite a conservative tuning strategy, the LR04 benthic stack exhibits significant coherency with insolation in the obliquity band throughout the entire 5.3 Myr and in the precession band for more than half of the record. The LR04 stack contains significantly more variance in benthic \u03b418O than previously published stacks of the late Pleistocene as the result of higher-resolution records, a better alignment technique, and a greater percentage of records from the Atlantic. Finally, the relative phases of the stack's 41- and 23-kyr components suggest that the precession component of \u03b418O from 2.7\u20131.6 Ma is primarily a deep-water temperature signal and that the phase of \u03b418O precession response changed suddenly at 1.6 Ma.", "keyphrases": ["stack", "benthic \u03b418o record", "benthic stack"]}
{"id": "paleo.012010", "title": "A Total-Evidence Approach to Dating with Fossils, Applied to the Early Radiation of the Hymenoptera", "abstract": "Abstract Phylogenies are usually dated by calibrating interior nodes against the fossil record. This relies on indirect methods that, in the worst case, misrepresent the fossil information. Here, we contrast such node dating with an approach that includes fossils along with the extant taxa in a Bayesian total-evidence analysis. As a test case, we focus on the early radiation of the Hymenoptera, mostly documented by poorly preserved impression fossils that are difficult to place phylogenetically. Specifically, we compare node dating using nine calibration points derived from the fossil record with total-evidence dating based on 343 morphological characters scored for 45 fossil (4--20 complete) and 68 extant taxa. In both cases we use molecular data from seven markers (\u223c5 kb) for the extant taxa. Because it is difficult to model speciation, extinction, sampling, and fossil preservation realistically, we develop a simple uniform prior for clock trees with fossils, and we use relaxed clock models to accommodate rate variation across the tree. Despite considerable uncertainty in the placement of most fossils, we find that they contribute significantly to the estimation of divergence times in the total-evidence analysis. In particular, the posterior distributions on divergence times are less sensitive to prior assumptions and tend to be more precise than in node dating. The total-evidence analysis also shows that four of the seven Hymenoptera calibration points used in node dating are likely to be based on erroneous or doubtful assumptions about the fossil placement. With respect to the early radiation of Hymenoptera, our results suggest that the crown group dates back to the Carboniferous, \u223c309 Ma (95% interval: 291--347 Ma), and diversified into major extant lineages much earlier than previously thought, well before the Triassic. [Bayesian inference; fossil dating; morphological evolution; relaxed clock; statistical phylogenetics.]", "keyphrases": ["dating", "early radiation", "hymenoptera", "morphological character", "phylogenetic analysis"]}
{"id": "paleo.004587", "title": "Early evolution of limb regeneration in tetrapods: evidence from a 300-million-year-old amphibian", "abstract": "Salamanders are the only tetrapods capable of fully regenerating their limbs throughout their entire lives. Much data on the underlying molecular mechanisms of limb regeneration have been gathered in recent years allowing for new comparative studies between salamanders and other tetrapods that lack this unique regenerative potential. By contrast, the evolution of animal regeneration just recently shifted back into focus, despite being highly relevant for research designs aiming to unravel the factors allowing for limb regeneration. We show that the 300-million-year-old temnospondyl amphibian Micromelerpeton, a distant relative of modern amphibians, was already capable of regenerating its limbs. A number of exceptionally well-preserved specimens from fossil deposits show a unique pattern and combination of abnormalities in their limbs that is distinctive of irregular regenerative activity in modern salamanders and does not occur as variants of normal limb development. This demonstrates that the capacity to regenerate limbs is not a derived feature of modern salamanders, but may be an ancient feature of non-amniote tetrapods and possibly even shared by all bony fish. The finding provides a new framework for understanding the evolution of regenerative capacity of paired appendages in vertebrates in the search for conserved versus derived molecular mechanisms of limb regeneration.", "keyphrases": ["limb regeneration", "tetrapod", "amphibian", "micromelerpeton"]}
{"id": "paleo.002985", "title": "Evolution of High Tooth Replacement Rates in Sauropod Dinosaurs", "abstract": "Background Tooth replacement rate can be calculated in extinct animals by counting incremental lines of deposition in tooth dentin. Calculating this rate in several taxa allows for the study of the evolution of tooth replacement rate. Sauropod dinosaurs, the largest terrestrial animals that ever evolved, exhibited a diversity of tooth sizes and shapes, but little is known about their tooth replacement rates. Methodology/Principal Findings We present tooth replacement rate, formation time, crown volume, total dentition volume, and enamel thickness for two coexisting but distantly related and morphologically disparate sauropod dinosaurs Camarasaurus and Diplodocus. Individual tooth formation time was determined by counting daily incremental lines in dentin. Tooth replacement rate is calculated as the difference between the number of days recorded in successive replacement teeth. Each tooth family in Camarasaurus has a maximum of three replacement teeth, whereas each Diplodocus tooth family has up to five. Tooth formation times are about 1.7 times longer in Camarasaurus than in Diplodocus (315 vs. 185 days). Average tooth replacement rate in Camarasaurus is about one tooth every 62 days versus about one tooth every 35 days in Diplodocus. Despite slower tooth replacement rates in Camarasaurus, the volumetric rate of Camarasaurus tooth replacement is 10 times faster than in Diplodocus because of its substantially greater tooth volumes. A novel method to estimate replacement rate was developed and applied to several other sauropodomorphs that we were not able to thin section. Conclusions/Significance Differences in tooth replacement rate among sauropodomorphs likely reflect disparate feeding strategies and/or food choices, which would have facilitated the coexistence of these gigantic herbivores in one ecosystem. Early neosauropods are characterized by high tooth replacement rates (despite their large tooth size), and derived titanosaurs and diplodocoids independently evolved the highest known tooth replacement rates among archosaurs.", "keyphrases": ["tooth", "replacement rate", "sauropod dinosaur"]}
{"id": "paleo.011656", "title": "Archaeological evidence for two separate dispersals of Neanderthals into southern Siberia", "abstract": "Significance Neanderthals once inhabited Europe and western Asia, spreading as far east as the Altai Mountains in southern Siberia, but the geographical origin and time of arrival of the Altai populations remain unresolved. Excavations at Chagyrskaya Cave in the Altai foothills have yielded 90,000 stone artifacts, numerous bone tools, 74 Neanderthal fossils, and animal and plant remains recovered from 59,000- to 49,000-year-old deposits. The Chagyrskaya Neanderthals made distinctive stone tools that closely resemble Micoquian artifacts from eastern Europe, whereas other Altai sites occupied by earlier Neanderthal populations lack such artifacts. This suggests at least two dispersals of Neanderthals into southern Siberia, with the likely ancestral homeland of the Chagyrskaya toolmakers located 3,000 to 4,000 kilometers to the west, in eastern Europe. Neanderthals were once widespread across Europe and western Asia. They also penetrated into the Altai Mountains of southern Siberia, but the geographical origin of these populations and the timing of their dispersal have remained elusive. Here we describe an archaeological assemblage from Chagyrskaya Cave, situated in the Altai foothills, where around 90,000 Middle Paleolithic artifacts and 74 Neanderthal remains have been recovered from deposits dating to between 59 and 49 thousand years ago (age range at 95.4% probability). Environmental reconstructions suggest that the Chagyrskaya hominins were adapted to the dry steppe and hunted bison. Their distinctive toolkit closely resembles Micoquian assemblages from central and eastern Europe, including the northern Caucasus, more than 3,000 kilometers to the west of Chagyrskaya Cave. At other Altai sites, evidence of earlier Neanderthal populations lacking associated Micoquian-like artifacts implies two or more Neanderthal incursions into this region. We identify eastern Europe as the most probable ancestral source region for the Chagyrskaya toolmakers, supported by DNA results linking the Neanderthal remains with populations in northern Croatia and the northern Caucasus, and providing a rare example of a long-distance, intercontinental population movement associated with a distinctive Paleolithic toolkit.", "keyphrases": ["dispersal", "neanderthals", "southern siberia"]}
{"id": "paleo.011536", "title": "Pros and cons of methylation-based enrichment methods for ancient DNA", "abstract": "The recent discovery that DNA methylation survives in fossil material provides an opportunity for novel molecular approaches in palaeogenomics. Here, we apply to ancient DNA extracts the probe-independent Methylated Binding Domains (MBD)-based enrichment method, which targets DNA molecules containing methylated CpGs. Using remains of a Palaeo-Eskimo Saqqaq individual, woolly mammoths, polar bears and two equine species, we confirm that DNA methylation survives in a variety of tissues, environmental contexts and over a large temporal range (4,000 to over 45,000 years before present). MBD enrichment, however, appears principally biased towards the recovery of CpG-rich and long DNA templates and is limited by the fast post-mortem cytosine deamination rates of methylated epialleles. This method, thus, appears only appropriate for the analysis of ancient methylomes from very well preserved samples, where both DNA fragmentation and deamination have been limited. This work represents an essential step toward the characterization of ancient methylation signatures, which will help understanding the role of epigenetic changes in past environmental and cultural transitions.", "keyphrases": ["enrichment method", "dna", "tissue"]}
{"id": "10.1111/j.1365-3121.2008.00856.x", "title": "Extinction, survival and recovery of corals from the Triassic to Middle Jurassic time", "abstract": "Recognizing extinction events and determining their cause at the Triassic/Jurassic (T/J) transition and near the Pliensbachian\u2013Toarcian (Lower Jurassic) boundary is a field of growing interest. We provide arguments for these events through a literature based new evaluation of coral diversity from Triassic to Dogger and a new palaeobiogeographical map. The T/J extinction of corals is clearly related to the breakdown of reef environments. Origination curves show that Hettangian (the lowest Jurassic stage) was not only a survival phase but already rather a recovery phase. Post\u2010extinction evolution of reefs and their survival only in the northernmost margin of the Tethys support the hothouse hypothesis for the T/J extinction event. During Pliensbachian, many new taxa appear, but mostly solitary corals, not really framebuilders. Many of these taxa do not occur anymore during the following stages. The new increase in diversity is related to the development of Bajocian (Middle Jurassic) reefs.", "keyphrases": ["survival", "coral", "triassic"]}
{"id": "10.5343/bms.2012.1076", "title": "How old is the Isthmus of Panama", "abstract": "The Standard Model of the formation of the Isthmus of Panama proposes that final closure occurred at 4-3 Ma. The model is based on evidence from studies of marine stratigraphy, fossil sequences, divergent molecular phylogenies, the timing of the Great American Biological Interchange (GABI), and proxies for marine paleosalinity, paleobathymetry, productivity, and paleotemperatures. The new model uses cooling of magmas in the Cretaceous to Early Miocene Central American Volcanic arc to propose Eocene emergence of the discrete structural blocks of the arc and then U/Pb dating, paleomagnetic pole rotations, and atlantic sea-floor anomalies to reconfigure the blocks for different time slices back to 25 Ma. Closure is proposed at 15 Ma, because by this time the alignment of the blocks leaves no space for trans-isthmian marine passages. We propose that the Indonesian Australian Archipelago (IAA) provides a model for the Central American arc between 15 and 3 Ma because it accounts for the extensive marine interchange between the Pacific and Indian oceans through few and narrow passages while maintaining a complete separation of the terrestrial faunas (Wallace and Lydekker lines) of the two continental platforms of Sunda and Sahul. Using the Indonesian Volcanic arc as a model, we can now accommodate the general tectonic configuration and much of the emergence of the new model, while accounting for the marine fossil record, the molecular evidence of rapid recent speciation, and the delayed Great American Biotic Interchange that the New Model fails to explain.", "keyphrases": ["isthmus", "panama", "closure"]}
{"id": "paleo.011671", "title": "Neuroanatomy of the mekosuchine crocodylian Trilophosuchus rackhami Willis, 1993", "abstract": "Although our knowledge on crocodylomorph palaeoneurology has experienced considerable growth in recent years, the neuroanatomy of many crocodylomorph taxa has yet to be studied. This is true for Australian taxa, where thus far only two crocodylian crocodylomorphs have had aspects of their neuroanatomy explored. Here, the neuroanatomy of the Australian mekosuchine crocodylian Trilophosuchus rackhami is described for the first time, which significantly increases our understanding on the palaeoneurology of Australian crocodylians. The palaeoneurological description is based on the taxon's holotype specimen (QMF16856), which was subjected to a \u03bcCT scan. Because of the exceptional preservation of QMF16856, most neuroanatomical elements could be digitally reconstructed and described in detail. Therefore, the palaeoneurological assessment presented here is hitherto the most in\u2010depth study of this kind for an extinct Australian crocodylomorph. Trilophosuchus rackhami has a brain endocast with a distinctive morphology that is characterized by an acute dural peak over the hindbrain region. While the overall morphology of the brain endocast is unique to T. rackhami, it does share certain similarities with the notosuchian crocodyliforms Araripesuchus wegeneri and Sebecus icaeorhinus. The endosseous labyrinth displays a morphology that is typical for crocodylians, although a stand\u2010out feature is the unusually tall common crus. Indeed, the common crus of T. rackhami has one of the greatest height ratios among crocodylomorphs with currently known endosseous labyrinths. The paratympanic pneumatic system of T. rackhami is greatly developed and most similar to those of the extant crocodylians Osteolaemus tetraspis and Paleosuchus palpebrosus. The observations on the neuroanatomy of T. rackhami are also discussed in the context of Crocodylomorpha. The comparative palaeoneurology reinforces previous evaluations that the neuroanatomy of crocodylomorphs is complex and diverse among species, and T. rackhami has a peculiar neuromorphology, particularly among eusuchian crocodyliforms.", "keyphrases": ["mekosuchine", "trilophosuchus rackhami", "qmf16856", "neuroanatomy", "ristevski"]}
{"id": "paleo.006587", "title": "Life history, sexual dimorphism and \u2018ornamental\u2019 feathers in the mesozoic bird Confuciusornis sanctus", "abstract": "The life history of Confuciusornis sanctus is controversial. Recently, the species\u2019 body size spectrum was claimed to contradict osteohistological evidence for a rapid, bird-like development. Moreover, sexual size dimorphism was rejected as an explanation for the observed bimodal size distribution since the presence of elongated rectrices, an assumed \u2018male\u2019 trait, was uncorrelated with size. However, this interpretation (i) fails to explain the size spectrum of C. sanctus which is trimodal rather than bimodal, (ii) requires implausible neonate masses and (iii) is not supported by analogy with sexual dimorphisms in modern birds, in which elongated central rectrices are mostly sex-independent. Available information on C. sanctus is readily reconciled if we assume a bird-like life history, as well as a pronounced sexual size dimorphism and sexually isomorphic extravagant feathers as frequently observed in extant species.", "keyphrases": ["sexual dimorphism", "feather", "confuciusornis sanctus", "bird-like life history", "life history"]}
{"id": "paleo.011034", "title": "The Antiquity of the Rhine River: Stratigraphic Coverage of the Dinotheriensande (Eppelsheim Formation) of the Mainz Basin (Germany)", "abstract": "Background Mammalian fossils from the Eppelsheim Formation (Dinotheriensande) have been a benchmark for Neogene vertebrate palaeontology since 200 years. Worldwide famous sites like Eppelsheim serve as key localities for biochronologic, palaeobiologic, environmental, and mammal community studies. So far the formation is considered to be of early Late Miocene age (\u223c9.5 Ma, Vallesian), representing the oldest sediments of the Rhine River. The stratigraphic unity of the formation and of its fossil content was disputed at times, but persists unresolved. Principal Findings Here we investigate a new fossil sample from Sprendlingen, composed by over 300 mammalian specimens and silicified wood. The mammals comprise entirely Middle Miocene species, like cervids Dicrocerus elegans, Paradicrocerus elegantulus, and deinotheres Deinotherium bavaricum and D. levius. A stratigraphic evaluation of Miocene Central European deer and deinothere species proof the stratigraphic inhomogenity of the sample, and suggest late Middle Miocene (\u223c12.5 Ma) reworking of early Middle Miocene (\u223c15 Ma) sediments. This results agree with taxonomic and palaeoclimatic analysis of plant fossils from above and within the mammalian assemblage. Based on the new fossil sample and published data three biochronologic levels within the Dinotheriensand fauna can be differentiated, corresponding to early Middle Miocene (late Orleanian to early Astaracian), late Middle Miocene (late Astaracian), and early Late Miocene (Vallesian) ages. Conclusions/Significance This study documents complex faunal mixing of classical Dinotheriensand fauna, covering at least six million years, during a time of low subsidence in the Mainz Basin and shifts back the origination of the Rhine River by some five million years. Our results have severe implications for biostratigraphy and palaeobiology of the Middle to Late Miocene. They suggest that turnover events may be obliterated and challenge the proposed \u2018supersaturated\u2019 biodiversity, caused by Middle Miocene superstites, of Vallesian ecosystems in Central Europe.", "keyphrases": ["dinotheriensande", "eppelsheim formation", "mainz basin", "late miocene"]}
{"id": "paleo.005914", "title": "A Gigantic, Exceptionally Complete Titanosaurian Sauropod Dinosaur from Southern Patagonia, Argentina", "abstract": "Titanosaurian sauropod dinosaurs were the most diverse and abundant large-bodied herbivores in the southern continents during the final 30 million years of the Mesozoic Era. Several titanosaur species are regarded as the most massive land-living animals yet discovered; nevertheless, nearly all of these giant titanosaurs are known only from very incomplete fossils, hindering a detailed understanding of their anatomy. Here we describe a new and gigantic titanosaur, Dreadnoughtus schrani, from Upper Cretaceous sediments in southern Patagonia, Argentina. Represented by approximately 70% of the postcranial skeleton, plus craniodental remains, Dreadnoughtus is the most complete giant titanosaur yet discovered, and provides new insight into the morphology and evolutionary history of these colossal animals. Furthermore, despite its estimated mass of about 59.3 metric tons, the bone histology of the Dreadnoughtus type specimen reveals that this individual was still growing at the time of death.", "keyphrases": ["titanosaurian sauropod dinosaur", "southern patagonia", "argentina", "dreadnoughtus schrani"]}
{"id": "paleo.007386", "title": "New teeth of allotherian mammals from the English Bathonian, including the earliest multituberculates", "abstract": "Twenty one isolated multituberculate-like teeth are described from the Forest Marble (late Bathonian) of Oxfordshire and Dorset, England. Eighteen are additional to the teeth described as Eleutherodon oxfordensis by Kermack et al. (1998), and three of those are placed in new taxa. Six new molars of Eleutherodon provide further information on variation in size, proportion and root pattern. Millsodon superstes gen. et sp. nov. (family indeterminate), based on first and last lower molars and a referred upper molar, has resemblances to Haramiyidae and Theroteinidae. Kirtlingtonia catenata gen. et sp. nov. (family indeterminate), based on last upper molars and a probable upper premolar, has a slight resemblance to Eleutherodon, and also to M2 of some paulchoffatiid multituberculates. Kermackodon multicuspis gen. et sp. nov. (family Kermackodontidae nov.) and Hahnotherium antiquum gen. et sp. nov. (family Hahnotheriidae nov.\n) are based on second upper molars, recognised as multituberculate by their horizontal wear and inferred occlusal displacement with respect to m2. A lower molar referred to H. antiquum confirms this. A blade-like lower premolar and an upper premolar with conical cusps, referred to Kermackodon, are multituberculate-like, but distinctive. Divergence between the two Bathonian multituberculates indicates that the order originated much earlier, more probably from a haramiyid than from a morganucodontid source. Mojo is regarded as probably a haramiyid. The Hahnodontidae, which have basined wear, are removed from the Multituberculata to the \"Haramiyida\".", "keyphrases": ["multituberculate", "haramiyidae", "tooth", "haramiyidan"]}
{"id": "10.4072/rbp.2011.1.06", "title": "First turtle from the Ipubi Formation (Early Cretaceous), Santana Group, Araripe Basin, Brazil", "abstract": "The Araripe Basin is located in northeastern Brazil between the states of Ceara, Piaui and Pernambuco (Figure 1). The Crato and Romualdo formations (Santana Group, see details in Neumann & Cabrera, 1999; Valenca et al., 2003) that comprise the most fossiliferous strata of this basin, are famous worldwide for the diverse and exquisitely well preserved fossil assemblages (e.g. Maisey, 1991). These two different lagerstatten were formed during the Lower Cretaceous, Aptian/Albian (Pons et al., 1990; ABSTRACT \u2013 Up to date turtle remains from the Early Cretaceous Santana Group are known only to the Crato and Romualdo formations (Aptian-Albian) that have yielded five species: Araripemys barretoi Price, 1973; Santanachelys gaffneyi Hirayama, 1998; Brasilemys josai Lapparent de Broin, 2000; Cearachelys placidoi Gaffney, Campos & Hirayama, 2001 and Euraxemys essweini Gaffney, Tong & Meylan, 2006. Except for A. barretoi, known from both, the Romualdo and Crato formations, all other turtle taxa are restricted to the Romualdo Formation. Fragments of the skull, an incomplete lower jaw and carapace of the first turtle remains from the Ipubi Formation are reported here. This material was collected in the shales above the gypsum layer, close to the contact with the Romualdo Formation (Aptian-Albian). Compared to other turtles from the Santana Group, this specimen is referred to Pelomedusoides, excluding Araripemys and Brasilemys, based on the following characteristics: absence of a cavum pterygoidei, absence of cervical scute, absence of fontanels in the carapace, contact between nuchal and first peripheral, and absence of nuchal emargination.", "keyphrases": ["turtle", "araripe basin", "crato formation"]}
{"id": "10.7152/jipa.v35i0.14727", "title": "A LONG PROCESS TOWARDS AGRICULTURE IN THE MIDDLE YELLOW RIVER VALLEY, CHINA: EVIDENCE FROM MACRO- AND MICRO-BOTANICAL REMAINS", "abstract": "Macro- and micro-botanical remains dating from the Upper Paleolithic through early Neolithic periods in North China have provided significant information for reconstructing the changing subsistence patterns as human groups evolved from mobile hunting-gathering societies to sedentary farming communities. Starch analysis on grinding stones, in particular, has revealed much new data that supplement the inventory of carbonized remains recovered by flotation methods. This paper reviews some recent research projects which have documented a long tradition of processing various plants with grinding stones in the Middle Yellow River valley, including tubers, beans, nuts, and cereals. Exploitation of wild millet can be traced back to 23,000-19,500 cal. BP, more than 10,000 years before its domestication. Several species of tuber, acorn, and wild grasses made up significant proportions of staple food during the early Neolithic, when millet domestication was already underway. These new data help us to better understand the extended transitional process to agriculture in the Middle Yellow River region. Archaeobotany is in an early stage of development in China; it is important to employ an interdisciplinary approach for a more complete documentation of plant use in the past and a better understanding of subsistence practices then.", "keyphrases": ["agriculture", "china", "macro-"]}
{"id": "paleo.006981", "title": "Gryposuchus (Crocodylia, Gavialoidea) from the early Miocene of Venezuela", "abstract": "Here, a fragment of a mandible recently discovered in the Cerro Zamuro site (Castillo Formation, Lara State, northwestern Venezuela) is assigned to the giant gavialoid Gryposuchus. This specimen, recovered from putative brackish environments of the early Miocene (*18 Ma) age, is unequivocally the earliest record of the genus in South America. Gryposuchus, together with the other gryposuchine previously recognized from the Castillo Formation, Siquisiquesuchus venezuelensis, increases the early Miocene taxonomic diversity of the group in the northern Neotropics. This new information from the Castillo Formation supports the conclusion that early gryposuchine evolutionary stages were in coastal, shallow marine or brackish environments, while the presence of some genera, such as Gryposuchus, in middle to late Miocene freshwater environments, is secondary habitat colonization late in the evolution of the clade. Freshwater colonization is probably the result of the gradual adaptation of early marine-adapted gryposuchines to the extensive estuarine-like environments of northern South America lowlands associated with marine transgressions that systematically occurred during the middle Eocene to early Oligocene. This new record is evidence of the wide chronological distribution of Gryposuchus in northern South America, highlighting the importance of this area as the center of origin and radiation of this successful Miocene gavialoid.", "keyphrases": ["early miocene", "castillo formation", "northern south america", "gryposuchus"]}
{"id": "10.1666/05072.1", "title": "When bivalves took over the world", "abstract": "Abstract The end-Permian mass extinction is commonly portrayed not only as a massive biodiversity crisis but also as the time when marine benthic faunas changed from the Paleozoic Fauna, dominated by rhynchonelliform brachiopod taxa, to the Modern Fauna, dominated by gastropod and bivalve taxa. After the end-Permian mass extinction, scenarios involving the Mesozoic Marine Revolution portray a steady increase in numerical dominance by these benthic molluscs as largely due to the evolutionary effects of an \u201carms race.\u201d We report here a new global paleoecological database from study of shell beds that shows a dramatic geologically sudden earliest Triassic takeover by bivalves as numerical dominants in level-bottom benthic marine communities, which continued through the Early Triassic. Three bivalve genera were responsible for this switch, none of which has any particular morphological features to distinguish it from many typical Paleozoic bivalve genera. The numerical success of these Early Triassic bivalves cannot be attributed to any of the well-known morphological evolutionary innovations of post-Paleozoic bivalves that characterize the Mesozoic Marine Revolution. Rather, their ability to mount this takeover most likely was due to the large extinction of rhynchonelliform brachiopods during the end-Permian mass extinction and aided by their environmental distribution and physiological characteristics that enabled them to thrive during periods of oceanic and atmospheric stress during the Permian/Triassic transition.", "keyphrases": ["bivalve", "mass extinction", "benthic faunas"]}
{"id": "paleo.012379", "title": "Decoupled taxonomic and ecological recoveries from the Permo-Triassic extinction", "abstract": "After the enormous Permian-Triassic mass extinction, marine animals high in the food chain recovered the most quickly. The Permian-Triassic mass extinction was the worst crisis faced by life; it killed >90% of marine species in less than 0.1 million years (Ma). However, knowledge of its macroecological impact over prolonged time scales is limited. We show that marine ecosystems dominated by non-motile animals shifted to ones dominated by nektonic groups after the extinction. In Triassic oceans, animals at high trophic levels recovered faster than those at lower levels. The top-down rebuilding of marine ecosystems was still underway in the latest Triassic, ~50 Ma after the extinction, and contrasts with the ~5-Ma recovery required for taxonomic diversity. The decoupling between taxonomic and ecological recoveries suggests that a process of vacant niche filling before reaching the maximum environmental carrying capacity is independent of ecosystem structure building.", "keyphrases": ["taxonomic", "ecological recovery", "recovery"]}
{"id": "paleo.011430", "title": "Competition structured a Late Cretaceous megaherbivorous dinosaur assemblage", "abstract": "Modern megaherbivore community richness is limited by bottom-up controls, such as resource limitation and resultant dietary competition. However, the extent to which these same controls impacted the richness of fossil megaherbivore communities is poorly understood. The present study investigates the matter with reference to the megaherbivorous dinosaur assemblage from the middle to upper Campanian Dinosaur Park Formation of Alberta, Canada. Using a meta-analysis of 21 ecomorphological variables measured across 14 genera, contemporaneous taxa are demonstrably well-separated in ecomorphospace at the family/subfamily level. Moreover, this pattern is persistent through the approximately 1.5 Myr timespan of the formation, despite continual species turnover, indicative of underlying structural principles imposed by long-term ecological competition. After considering the implications of ecomorphology for megaherbivorous dinosaur diet, it is concluded that competition structured comparable megaherbivorous dinosaur communities throughout the Late Cretaceous of western North America.", "keyphrases": ["dinosaur assemblage", "north america", "competition"]}
{"id": "10.1017/s0094837300009982", "title": "Experimental disintegration of regular echinoids: roles of temperature, oxygen, and decay thresholds", "abstract": "Laboratory experiments on regular echinoids indicate that low water temperatures retard organic decomposition far more effectively than anoxia, and that the primary role of anoxia in the preservation of articulated multi-element calcareous skeletons may be in excluding scavenging organisms. When tumbled at 20 rpm, specimens that were first allowed to decay for two days in warm seawater (30\u00b0C) disintegrated more than six times faster than specimens treated at room temperature (23\u00b0C) and more than an order of magnitude faster than specimens treated in cool water (11\u00b0C). In contrast, the effects of aerobic versus anerobic decay on disintegration rates were insignificant. The longer the period that specimens were allowed to decay before tumbling, the greater the rate at which specimens disintegrated, until a threshold time that appears to mark the decomposition of collagenous ligaments. This required a few days at 30\u00b0C, about two weeks at 23\u00b0C, and more than 4 weeks at 11\u00b0C for Strongylocentrotus. Up until this threshold, coronas disintegrate by a combination of cross-plate fractures and separation along plate sutures; cross-plate fractures thus can be taphonomic in origin and are not necessarily related to predation. Specimens decayed for longer-than-threshold periods of time disintegrate virtually instantaneously upon tumbling by sutural separation only. Undisturbed coronas can remain intact for months, sufficient time for epibiont occupation. Rates of disintegration were documented semi-quantitatively by recognizing seven stages of test disarticulation, and quantitatively by tensometer measures of test strength and toughness. The effects of temperature and oxygen on decay and the existence of a decay threshold in disintegration should apply at least in a qualitative sense to many other animals whose skeletons consist of multiple, collagen-bound elements. Regular echinoids should still be perceived as taphonomically fragile organisms, but our results suggest the potential for latitudinal as well as bathymetric gradients in the preservation of fossil echinoid faunas. Echinoid preservation under any given set of conditions should also be a function of taxonomic differences in test construction (particularly stereom interlocking along plate sutures) as suggested by previous workers, although our experiments indicate that these effects should only be significant among post-threshold specimens. A survey of regular echinoids from Upper Cretaceous white chalk facies of Britain substantiates the basic experimental patterns, yielding examples of all disarticulation stages and significant taxonomic differences in quality of preservation. A diverse array of borers and encrusters on fossil coronas also corroborates the post-mortem persistence of some tests on mid-latitude seafloors.", "keyphrases": ["disintegration", "regular echinoid", "oxygen", "plate suture"]}
{"id": "10.1073/pnas.1410735111", "title": "Temporal labyrinths of eastern Eurasian Pleistocene humans", "abstract": "Significance The assessment of the paleobiology and morphological affinities of the Neandertals and other Late Pleistocene archaic humans is central to resolving issues regarding the emergence and establishment of modern human morphology and diversity. One feature, which has been used as a distinctive Neandertal feature in this context, is the apparently derived shape of their temporal labyrinths (especially semicircular canals). Analysis of East Asian labyrinths documents the \u201cNeandertal\u201d pattern in the Xujiayao 15 temporal bone, although none of the Xujiayao human remains exhibits other distinctly Neandertal features. It therefore raises questions regarding possible biological correlates of labyrinthine morphology, distinctive Neandertal features, and the nature of late archaic human variation across Eurasia. One of the morphological features that has been identified as uniquely derived for the western Eurasian Neandertals concerns the relative sizes and positions of their semicircular canals. In particular, they exhibit a relatively small anterior canal, a relatively larger lateral one, and a more inferior position of the posterior one relative to the lateral one. These discussions have not included full paleontological data on eastern Eurasian Pleistocene human temporal labyrinths, which have the potential to provide a broader context for assessing Pleistocene Homo trait polarities. We present the temporal labyrinths of four eastern Eurasian Pleistocene Homo, one each of Early (Lantian 1), Middle (Hexian 1), and Late (Xujiayao 15) Pleistocene archaic humans and one early modern human (Liujiang 1). The labyrinths of the two earlier specimens and the most recent one conform to the proportions seen among western early and recent modern humans, reinforcing the modern human pattern as generally ancestral for the genus Homo. The labyrinth of Xujiayao 15 is in the middle of the Neandertal variation and separate from the other samples. This eastern Eurasian labyrinthine dichotomy occurs in the context of none of the distinctive Neandertal external temporal or other cranial features. As such, it raises questions regarding possible cranial and postcranial morphological correlates of Homo labyrinthine variation, the use of individual \u201cNeandertal\u201d features for documenting population affinities, and the nature of late archaic human variation across Eurasia.", "keyphrases": ["labyrinth", "pleistocene", "xujiayao"]}
{"id": "10.1206/653.1", "title": "The Basal Penguin (Aves: Sphenisciformes) Perudyptes devriesi and a Phylogenetic Evaluation of the Penguin Fossil Record", "abstract": "Abstract We present the first detailed description of Perudyptes devriesi, a basal penguin from the middle Eocene (~42 Ma) Paracas Formation of Peru, and a new analysis of all published extinct penguin species as well as controversial fragmentary specimens. The Perudyptes devriesi holotype includes key regions of the skull and significant postcranial material, thus helping to fill a major phylogenetic and stratigraphic (~20 million year) gap between the earliest fossil penguins (Waimanu manneringi and Waimanu tuatahi, ~58\u201361.6 Ma) and the next oldest partial skeletons. Perudyptes devriesi is diagnosable by five autapomorphies: (1) an anteroventrally directed postorbital process, (2) marked anterior expansion of the parasphenoid rostrum, (3) posterior trochlear ridge of the humerus projecting distal to the middle trochlear ridge and conformed as a large, broadly curved surface, (4) convex articular surface for the antitrochanter of the femur, and (5) extremely weak anterior projection of the lateral condyle of the tibiotarsus. The skull of Perudyptes is characterized by deep temporal fossae and an elongate, narrow beak that differs from other reported stem penguins in its short mandibular symphysis. The wing skeleton of Perudyptes preserves a combination of plesiomorphic features also observed in the basal penguin Waimanu and derived features shared with more crownward penguins. Features of the wing optimized as primitive for Sphenisciformes include retention of a discrete dorsal supracondylar tubercle on the humerus and presence of a modestly projected pisiform process on the carpometacarpus. Derived features present in Perudyptes and all more crownward penguins, but absent in Waimanu, include a more flattened humerus, development of a trochlea for the tendon of m. scapulotriceps at the distal end of the humerus, and bowing of the anterior face of the carpometacarpus. A combined molecular and morphological dataset for Spheniciformes was expanded by adding 25 osteological and soft tissue characters as well as 11 taxa. In agreement with previous results, Perudyptes devriesi is identified as one of the most basal members of Sphenisciformes. This analysis also confirms the placement of the middle/late Miocene (~11\u201313 Ma) fossil Spheniscus muizoni as a member of the Spheniscus clade and places the late Miocene (~10 Ma) Madrynornis mirandus as sister taxon to extant Eudyptes. These two species, known from relatively complete partial skeletons, are the oldest crown clade penguin fossils and represent well-corroborated temporal calibration points for the Spheniscus-Eudyptula divergence and Megadyptes-Eudyptes divergence, respectively. Our results reaffirm that the Miocene penguin taxon Palaeospheniscus, recently proposed to represent a member of the crown radiation, belongs outside of the crown clade Spheniscidae. The phylogenetic positions of small Eocene Antarctic penguin taxa (Delphinornis, Marambiornis, and Mesetaornis) recently proposed as possible direct ancestors to crown Spheniscidae were further evaluated using alternate coding strategies for incorporating scorings from isolated elements that preserve critical morphologies and are thought to represent these taxa, although they cannot yet be reliably assigned to individual species. Under all scoring regimes, Delphinornis, Marambiornis, and Mesetaornis were recovered as distantly related to Spheniscidae. Using synapomorphies identified in the primary analysis, we evaluated the phylogenetic position of fragmentary specimens, including the holotypes of valid but poorly known species, specimens currently unassignable to the species level, and morphologically distinct specimens that have not yet been named. All pre-Miocene specimens can be excluded from Spheniscidae based on presence of plesiomorphies lost in all crown penguins, consistent with a recent radiation for the penguin crown clade. This study provides additional support for a scenario of penguin evolution characterized by an origin of flightlessness near the K-T boundary, dispersal throughout the Southern Hemisphere during the early Paleogene, and a late Cenozoic origin for the crown clade Spheniscidae. Stratigraphic distribution and phylogenetic relationships of fossil penguins are consistent with distinct radiations during the Eocene, Oligocene, and Miocene. While the Eocene and Oligocene penguin faunas are similar in many respects, the Miocene fauna is characterized by smaller average size and novel cranial morphologies, suggesting that an ecological shift in diet occurred close to the origin of crown Spheniscidae.", "keyphrases": ["basal penguin", "sphenisciforme", "perudyptes devriesi"]}
{"id": "paleo.008354", "title": "First Evidence of Dinosaurian Secondary Cartilage in the Post-Hatching Skull of Hypacrosaurus stebingeri (Dinosauria, Ornithischia)", "abstract": "Bone and calcified cartilage can be fossilized and preserved for hundreds of millions of years. While primary cartilage is fairly well studied in extant and fossilized organisms, nothing is known about secondary cartilage in fossils. In extant birds, secondary cartilage arises after bone formation during embryonic life at articulations, sutures and muscular attachments in order to accommodate mechanical stress. Considering the phylogenetic inclusion of birds within the Dinosauria, we hypothesized a dinosaurian origin for this \u201cavian\u201d tissue. Therefore, histological thin sectioning was used to investigate secondary chondrogenesis in disarticulated craniofacial elements of several post-hatching specimens of the non-avian dinosaur Hypacrosaurus stebingeri (Ornithischia, Lambeosaurinae). Secondary cartilage was found on three membrane bones directly involved with masticatory function: (1) as nodules on the dorso-caudal face of a surangular; and (2) on the bucco-caudal face of a maxilla; and (3) between teeth as islets in the alveolar processes of a dentary. Secondary chondrogenesis at these sites is consistent with the locations of secondary cartilage in extant birds and with the induction of the cartilage by different mechanical factors - stress generated by the articulation of the quadrate, stress of a ligamentous or muscular insertion, and stress of tooth formation. Thus, our study reveals the first evidence of \u201cavian\u201d secondary cartilage in a non-avian dinosaur. It pushes the origin of this \u201cavian\u201d tissue deep into dinosaurian ancestry, suggesting the creation of the more appropriate term \u201cdinosaurian\u201d secondary cartilage.", "keyphrases": ["dinosaurian", "cartilage", "hypacrosaurus stebingeri"]}
{"id": "10.1017/pab.2015.33", "title": "Comparative dental microwear of ruminant and perissodactyl molars: Implications for paleodietary analysis of rare and extinct ungulate clades", "abstract": "Abstract. Dental microwear analyses of ungulates and other large herbivores rely on correlations of diet and microwear among extant ungulates, primarily ruminants. Microwear is considered a \u2018taxon-free\u2019 method of paleodietary analysis. The properties of food are associated with causality of microwear, but the possibility that heritable properties of the consumer (tooth morphologies, masticatory dynamics, enamel mechanical properties, digestive physiologies) may introduce bias is not considered. Using an observer blind method of light microscopy, we examined the distribution of microwear features on the molars of eight species of ruminants and perissodactyls. Grazing and browsing ruminants had statistically different numbers of scratches forming discrete data clusters. Perissodactyls differ in the numbers of scratches and pits but without discrete browser and grazer clusters. Microwear features were distributed homogeneously across ruminantmolars and strongly predictive of diet fromthe labial edge of the molar to the lingual edge. Microwear was heterogeneously distributed across perissodactyl molars with more pits on the labial edge andmore scratches on the lingual edge. In perissodactyls, microwear sampled from the labial edge was strongly predictive of diet, while microwear sampled from other areas were not. Discriminant function analyses of microwear assigned individual molars to diets (browser and grazer) and clades (ruminant and perissodactyl) with similar success (70\u201373%) indicating that phylogeny and diet influencemicrowear equally. Rhino microwear was more sensitive to clade membership while other perissodactyl microwear was more sensitive to diet. Although it is not clear what heritable variables may phylogenetically bias dentalmicrowear, extant ruminants may not be appropriate models for themicrowear of other large herbivores.", "keyphrases": ["microwear", "perissodactyl molar", "paleodietary analysis"]}
{"id": "10.17161/np.v0i9.4765", "title": "Whipspiders (Arachnida: Amblypygi) in amber from the Early Eocene and mid-Cretaceous, including maternal care", "abstract": "Two new genera and species of fossil whipspiders (Chelicerata: Arachnida: Amblypygi) are described from Tertiary and Cretaceous ambers of southern Asia.\u00a0 Paracharonopsis cambayensis Engel & Grimaldi, new genus and species, preserved in Cambay amber of Ypresian age from western India is the first Tertiary and Asian fossil of the Paleoamblypygi, a highly relict taxon that includes the Late Carboniferous genus Graeophonus Scudder and the living West African species Paracharon caecus Hansen.\u00a0 Paracharonopsis cambayensis is one of the few examples in Cambay amber of a biotic connection to Africa; most taxa show widespread or Laurasian distributions.\u00a0 Kronocharon prendinii Engel & Grimaldi, new genus and species, is the first Cretaceous amber whipspider and putatively a sister group to the Phrynoidea (= Apulvillata).\u00a0 The holotype female of K. prendinii is preserved with the remains of three nymphs near her, documenting the Early Cretaceous presence of the extended maternal care so distinctive for the order, and a behavioral repertoire widespread among arachnids.", "keyphrases": ["arachnida", "amblypygi", "care"]}
{"id": "10.1671/039.029.0103", "title": "An Oligo-Miocene Magpie Goose (Aves: Anseranatidae) from Riversleigh, Northwestern Queensland, Australia", "abstract": "ABSTRACT The magpie goose Anseranas semipalmata (Aves: Anseranatidae), the sole modern representative of the family, is endemic to Australia. The fossil record of Anseranatidae in Australia was until now restricted to Pliocene and younger sediments. Here we describe an anseranatid from the Oligo-Miocene Carl Creek Limestone in the Riversleigh World Heritage Property, Boodjamulla (Lawn Hill) National Park, in northwestern Queensland, as a new species and genus, based on a coracoid and two scapulae. These fossils extend the known age of the Anseranatidae lineage in Australia to about 25 million years ago. The fossil distribution of Anseranatidae now includes the Paleocene in North America, Eocene and Late Oligocene of Europe, and the Late Oligocene to earliest Miocene in Australia, indicating a globally widespread distribution of the family during the early-mid Tertiary.", "keyphrases": ["anseranatidae", "riversleigh", "northwestern queensland"]}
{"id": "10.1017/S0094837300006813", "title": "Functional analysis of sabertooth cranial morphology", "abstract": "Elongate canines evolved independently at least four times among mammalian carnivores, and each time skulls were modified in similar ways. We have compared the cranial morphology of sabertooths to that of their non-sabertoothed relatives, living and extinct, and applied simple biomechanical models to elucidate the functional significance of the morphological differences. Our analysis suggests that (1) sabertooth morphology represents modification for wider gape with retention of a powerful bite force at the carnassial; (2) sabertooths probably used a throat or ventral neck slash to kill prey; and (3) elongate canines and retractile claws may have facilitated the exploitation of relatively larger prey by sabertooths compared to non-sabertooth carnivores.", "keyphrases": ["morphology", "sabre-tooth morphology", "similar ecomorphologie", "functional difference"]}
{"id": "paleo.002772", "title": "The oldest ammonoids of Morocco (Tafilalt, lower Emsian)", "abstract": "During a fieldtrip of the 10th International Cephalopod Symposium to the Tafilalt (SE Morocco), a fauna with the so far oldest ammonoid of the region was discovered at the top of the basal Emsian Deiroceras Limestone of Jebel Mech Irdane. The new material confirms the record of a single, poorly preserved specimen of the same age from Ras El Kebbar in the northwestern Tafilalt. All specimens are assigned within the Chebbitinae n. subfam. (Mimosphinctidae) to Praechebbites debaetsi n. gen. n. sp., which differs from the slightly younger Chebbites reisdorfi mostly in the lack of a dorsal lobe and dorsal imprint zone. In the conodont succession, the new species and genus falls in the top of the Eolinguipolygnathus excacatus M114 Zone, which has been proposed to define in future the base of the Emsian. Since the new taxon is morphologically already advanced, it is likely that even older ammonoids with loosely coiled conchs will be discovered in the future. A block from a Lower Carboniferous olistostrome of the adjacent Tinerhir region contained the gyroconic Ivoites n. sp. only. The global comparison of oldest ammonoid faunas shows the rarity of assemblages assigned to Lower Devonian (LD) III-B, often dated by conodonts and dacryoconarids. These faunas display a high level of endemism, which suggests that ammonoid origin and early evolution took place in regional populations with a restricted dispersal of genera and species.", "keyphrases": ["ammonoid", "morocco", "tafilalt"]}
{"id": "10.11646/palaeoentomology.2.4.13", "title": "Disambiguating the scientific names of cockroaches", "abstract": "Cockroaches are typically recognized as an order or a suborder in insects, sometimes rank-free. Many scientific names for cockroaches are in use, most of them are ambiguous because of frequent changes of the spelling and definition, and the discrepancy between phenetics and cladistics. Omission of the authorship of the name and of the definition further confuses readers, which include taxonomists. The underlying causes of the ambiguity are the paraphyly of cockroaches and various reproduction strategies (crucial in cockroach classification) of fossil cockroaches. This paper historically reviews the scientific names for cockroaches, and recommends the following names with phylogenetic definition (details and authorship are given in the text): 1) Blattodea are cockroaches with internal ovipositors (producing oothecae of the extant type) and all descendants including termites; 2) suborder Blattaria are Blattodea minus termites; 3) order Dictyoptera are cockroaches that produce genuine oothecae and all descendants including Blattodea, Mantodea and Alienoptera; 4) Holopandictyoptera are all insects that are recognized as cockroaches and their descendants; 5) Eoblattodea are the so-called \u2018roachoids\u2019, i.e., cockroaches bearing long external ovipositors, no genuine oothecae. Accordingly, the cockroaches in the broader sense fall into three taxa: Blattaria, basal Dictyoptera, and Eoblattodea.", "keyphrases": ["scientific name", "cockroach", "ovipositor"]}
{"id": "10.5194/bg-2-133-2005", "title": "Non-invasive diagnostics in fossils - Magnetic Resonance Imaging of pathological belemnites", "abstract": "Abstract. For more than a decade, Magnetic Resonance Imaging (MRI) has been routinely employed in clinical diagnostics because it allows non-invasive studies of anatomical structures and physiological processes in vivo and to differentiate between healthy and pathological states, particularly of soft tissue. Here, we demonstrate that MRI can likewise be applied to fossilized biological samples and help in elucidating paleopathological and paleoecological questions: Five anomalous guards of Jurassic and Cretaceous belemnites are presented along with putative paleopathological diagnoses directly derived from 3D MR images with microscopic resolution. Syn vivo deformities of both the mineralized internal rostrum and the surrounding former soft tissue can be traced back in part to traumatic events of predator-prey-interactions, and partly to parasitism. Besides, evidence is presented that the frequently observed anomalous apical collar might be indicative of an inflammatory disease. These findings highlight the potential of Magnetic Resonance techniques for further paleontological applications.", "keyphrases": ["diagnostic", "magnetic resonance imaging", "belemnite"]}
{"id": "paleo.008175", "title": "The labyrinthine morphology of Pronycticebus gaudryi (Primates, Adapiformes)", "abstract": "The publication of a well preserved Eocene primate, Darwinius masillae (Cercamoniinae, Notharctidae), has revived the debate on the phylogenetic relationships of Adapiformes and extant primates (Franzen et al., PLos ONE 4(5):e5723, 2009). Recently, Lebrun et al. (J Anat 216:368-380, 2010) showed that the morphology of the bony labyrinth of strepsirrhine primates conveys a strong phylogenetic signal. The study of labyrinthine morphology may thus bring a new piece of evidence to resolve phylogenetic relationships within a group. The investigation of the labyrinthine morphology of another Cercamoniinae, Pronycticebus gaudryi, reveals no synapomorphy with the labyrinths of modern anthropoids. On the contrary, Pronycticebus is closer in labyrinthine shape to extant strepsirrhines, which supports the hypothesis that the Cercamoniinae and other Adapiformes are the sister group of toothcombed primates.", "keyphrases": ["labyrinthine morphology", "morphology", "pronycticebus", "adapiformes", "phylogenetic relationship"]}
{"id": "paleo.000221", "title": "Description of a fossil camelid from the Pleistocene of Argentina, and a cladistic analysis of the Camelinae", "abstract": "We describe a well-preserved South American Lamini partial skeleton (PIMUZ A/V 4165) from the Ensenadan (~ 1.95-1.77 to 0.4 Mya) of Argentina. The specimen is comprised of a nearly complete skull and mandible with full tooth rows, multiple elements of anterior and posterior limbs, and a scapula. We tested this specimen's phylogenetic position and hypothesized it to be more closely related to Lama guanicoe and Vicugna vicugna than to Hemiauchenia paradoxa. We formulate a hypothesis for the placement of PIMUZ A/V 4165 within Camelinae in a cladistic analysis based on craniomandibular and dental characters and propose that future systematic studies consider this specimen as representing a new species. For the first time in a morphological phylogeny, we code terminal taxa at the species level for the following genera: Camelops, Aepycamelus, Pleiolama, Procamelus, and Alforjas. Our results indicate a divergence between Lamini and Camelini predating the Barstovian (16 Mya). Camelops appears as monophyletic within the Camelini. Alforjas taylori falls out as a basal member of Camelinae-neither as a Lamini nor Camelini. Pleiolama is polyphyletic, with Pleiolama vera as a basal Lamini and Pleiolama mckennai in a more nested position within the Lamini. Aepycamelus and Procamelus are respectively polyphyletic and paraphyletic. Together, they are part of a group of North American Lamini from the Miocene epoch.", "keyphrases": ["pleistocene", "argentina", "camelinae"]}
{"id": "10.1144/SP423.11", "title": "Brachiopod faunas, facies and biostratigraphy of the Pridolian to lower Eifelian succession in the Rhenish Massif (Rheinisches Schiefergebirge, Germany)", "abstract": "Abstract The succession of Pridolian to lower Eifelian (uppermost Silurian to lowermost Middle Devonian) rhynchonelliformean brachiopod faunas from the Rhenish Massif (Germany) is described and interpreted against the background of sedimentary sequences and facies development. The predominant rhenotypic (\u2018Rhenish\u2019) facies is redefined as a neritic-siliciclastic facies type of the Devonian. It is subdivided into eurhenotypic, pararhenotypic and allorhenotypic subfacies, based on sedimentary features and specific brachiopod assemblages reflecting different shallow-marine palaeoenvironments under more or less terrigenous influence. The studied sedimentary successions are subdivided biostratigraphically on the basis of brachiopods, correlated on a supraregional scale, and calibrated in terms of the global chronostratigraphy. Stratigraphic intervals with characteristic brachiopod faunas are distinguished. Faunal turnovers between these are attributed to regional events in the context of short or more extended phases of palaeoenvironmental change presumably caused mainly by sea-level fluctuations in combination with varying crustal subsidence and sedimentation rates. These changes resulted in shelf-wide or more regional extinction or emigration of substantial parts of a brachiopod fauna and subsequent replacement by a largely new one. Finally, new taxa of brachiopods are introduced: Sartenaerirhynchus gen. nov., Paraspirifer (Mosellospirifer) subgen. nov., Paraspirifer (Laurentispirifer) subgen. nov., Iridistrophia (Flabellistrophia) subgen. nov. and Iridistrophia (Flabellistrophia) musculosa sp. nov.", "keyphrases": ["pridolian", "succession", "sedimentary sequence", "brachiopod faunas"]}
{"id": "10.1144/jgs2016-059", "title": "A new Lagerst\u00e4tte from the Late Ordovician Big Hill Formation, Upper Peninsula, Michigan", "abstract": "A new exceptionally preserved marginal marine biota is reported from the Late Ordovician Big Hill Formation of Stonington Peninsula in Michigan's Upper Peninsula. The new Lagerst\u00e4tte hosts a moderately diverse fauna of medusae, linguloid brachiopods, non-mineralized arthropods and orthocone nautiloids, alongside dasycladalean green algae. The biota is similar to those of Lagerst\u00e4tten from the Late Ordovician of Canada, revealing an extensive distribution of a distinctive marginal marine palaeocommunity in Laurentia at this time. The Big Hill biota extends the geographical range of exceptionally preserved Late Ordovician faunas in Laurentia and indicates that further examples remain to be discovered.", "keyphrases": ["new lagerst\u00e4tte", "late ordovician", "big hill formation", "upper peninsula", "biota"]}
{"id": "10.54991/jop.1976.1015", "title": "The age of the Tiki formation: with remarks on the miofloral succession in the Triassic Gondwanas of India", "abstract": "The age of the Tiki Formation in the South Rewa Gondwana Basin has been discussed. Available data on the vertebrate fauna, megaflora and palynoflora of the Tiki Formation have been evaluated. It is concluded that the Tiki Formation sensu lato (i.e. including the Nidhpuri beds) ranges in age from Anisian through Norian and possibly extends into the Rhaetian. \nOn the basis of available palynological data an attempt has been made to establish the miofloral succession in the Triassic Gondwanas of India. Presently nine successive palynological zones have been recognized. However, possibility of existence of some more palynological zones is also not ruled out.", "keyphrases": ["tiki formation", "miofloral succession", "triassic gondwanas"]}
{"id": "paleo.009616", "title": "Mouthpart homologies and life habits of Mesozoic long-proboscid scorpionflies", "abstract": "Long-proboscid scorpionflies from amber reveal the variety and complexity of mid-Cretaceous pollinating insects. Mesozoic long-proboscid scorpionflies (Mesopsychoidea) provide important clues to ancient plant-pollinator interactions. Among them, the family Aneuretopsychidae is especially important because its mouthparts are vital to deciphering the early evolution of Mesopsychoidea and putatively the origin of fleas (Siphonaptera). However, the identification of mouthpart homologs among Aneuretopsychidae remains controversial because of the lack of three-dimensional anatomical data. Here, we report the first Aneuretopsychidae from Late Cretaceous Burmese amber, which have short maxillary palpi and elongate mouthpart elements consisting of one pair of galeae and one hypopharynx. Their mouthparts are identical to those of Pseudopolycentropodidae (= Dualulidae, new synonym) but are not homologous to those of Siphonaptera. Our phylogenetic analysis provides robust evidence for the debated monophyly of Mesopsychoidea. Our results suggest that the long-proboscid condition has most likely evolved once in Mesopsychoidea, independently from fleas, and further reveal the variety and complexity of mid-Cretaceous pollinating insects.", "keyphrases": ["mesozoic long-proboscid scorpionflie", "scorpionflie", "mouthpart"]}
{"id": "paleo.008130", "title": "Cincinnetina, a new Late Ordovician dalmanellid brachiopod from the Cincinnati type area, USA: implications for the evolution and palaeogeography of the epicontinental fauna of Laurentia", "abstract": "Abstract:\u2002 The most common forms of Late Ordovician dalmanellid brachiopods from the Cincinnatian type area, previously treated as either Dalmanella or Onniella, are assigned to Cincinnetina gen. nov. The new genus differs from Dalmanella and Onniella in having a consistently developed primary medial costa in the dorsal valve, a larger cardinal process that tends to develop a trilobed myophore, strongly differentiated fine and coarse punctae, and sparse aditicules. Cincinnetina can be distinguished from the closely related Paucicrura and Diceromyonia in its smaller trilobed cardinal process (when developed) that does not have a dominant medial lobe and does not extend into the delthyrial cavity of the ventral valve. Globally, Dalmanella and Onniella occur most commonly in deposits of relatively deep\u2010 or cool\u2010water palaeoecological settings, whereas in North America, Cincinnetina, Paucicrura and Diceromyonia are found mainly in carbonate\u2010rich deposits in warm\u2010water depositional environments, with Cincinnetina and Paucicrura most common in pericratonic settings and Diceromyonia in palaeoequatorial inland seas.", "keyphrases": ["ordovician dalmanellid brachiopod", "brachiopod", "cincinnetina"]}
{"id": "10.2307/1564173", "title": "Sources of Heat for Nests of Paleosuchus trigonatus and a Review of Crocodilian Nest Temperatures", "abstract": "All species of crocodilian that have been studied normally incubate their eggs at temperatures above 27?C. Stable temperatures above 27?C are not naturally available in the tropical- rainforest habitat of Paleosuchus trigonatus, and our investigations indicate that its nests are not warmed by the processes that have been suggested for nests of other species: insolation, rotting vegetation, and metabolic heat of embryos. Most nests of P. trigonatus are placed at the side of, or on top of, termite mounds. Heat from the termite mound and insulation by the nest material maintain the eggs at about 30?C (28.4-32.1?C).", "keyphrases": ["heat", "nest", "paleosuchus trigonatus"]}
{"id": "10.1002/ajpa.22727", "title": "Skeletal evidence of tuberculosis in a modern identified human skeletal collection (Certosa cemetery, Bologna, Italy).", "abstract": "The diagnosis of tuberculosis (TB) in osteoarcheological series relies on the identification of osseous lesions caused by the disease. The study of identified skeletal collections provides the opportunity to investigate the distribution of skeletal lesions in relation to this disease. The aim of this study was to examine the skeletal evidence for TB in late adolescent and adult individuals from the identified human collection of the Certosa cemetery of Bologna (Italy, 19th-20th c.). The sample group consists of 244 individuals (138 males, 106 females) ranging from 17 to 88 years of age. The sample was divided into three groups on the basis of the recorded cause of death: TB (N = 64), pulmonary non-TB (N = 29), and other diseases (N = 151). Skeletal lesions reported to be related to TB were analyzed. The vertebral lesions were classified into three types: enlarged foramina (EnF, vascular foramina with diameter of 3-5 mm), erosions (ER), and other foramina (OtF, cavities of various shapes > 3 mm). A CT scan analysis was also performed on vertebral bodies. Some lesions were seldom present in our sample (e.g., tuberculous arthritis). OtF (23.7%) and subperiosteal new bone formation on ribs (54.2%) are significantly more frequent in the TB group with respect to the other groups. The CT scan analysis showed that the vertebrae of individuals who have died of TB may have internal cavities in the absence of external lesions. These traits represent useful elements in the paleopathological diagnosis of TB.", "keyphrases": ["tuberculosis", "skeletal collection", "certosa cemetery", "identification", "paleopathological diagnosis"]}
{"id": "10.1098/rspb.2009.2177", "title": "Explosive morphological diversification of spiny-finned teleost fishes in the aftermath of the end-Cretaceous extinction", "abstract": "The spiny-finned teleost fishes (Acanthomorpha) include nearly one-third of all living vertebrate species and assume a bewildering array of bodyplans, but the macroevolutionary assembly of modern acanthomorph biodiversity remains largely unexplored. Here, I reconstruct the trajectory of morphological diversification in this major radiation from its first appearance in the Late Cretaceous to the Miocene using a geometric morphometric database comprising more than 600 extinct species known from complete body fossils. The anatomical diversity (disparity) of acanthomorphs is low throughout the Cretaceous, increases sharply and significantly in the wake of the Cretaceous\u2013Palaeogene (K\u2013P) extinction, and shows little change throughout subsequent Cenozoic intervals. This pattern of morphological diversification appears robust to two potential biasing factors: the \u2018Lagerst\u00e4tten effect\u2019, and the non-random segregation of rare and common taxa along phenotypic axes. Dissecting the trajectory of acanthomorph radiation along phylogenetic lines reveals that the abrupt post-extinction increase in disparity is driven largely by the proliferation of trophically diverse modern groups within Percomorpha, a spiny-fin subclade containing more than 15 000 living species and identified as showing a substantially elevated diversification rate relative to background vertebrate levels. A major component of the Palaeogene acanthomorph radiation reflects colonization of morphospace previously occupied by non-acanthomorph victims of the K\u2013P. However, other aspects of morphological diversification cannot be explained by this simple ecological release model, suggesting that multiple factors contributed to the prolific anatomical radiation of acanthomorphs.", "keyphrases": ["morphological diversification", "diversification", "spiny-finned teleost fish", "acanthomorph"]}
{"id": "paleo.011673", "title": "Bayesian phylogenetic estimation of fossil ages", "abstract": "Recent advances have allowed for both morphological fossil evidence and molecular sequences to be integrated into a single combined inference of divergence dates under the rule of Bayesian probability. In particular, the fossilized birth\u2013death tree prior and the Lewis-Mk model of discrete morphological evolution allow for the estimation of both divergence times and phylogenetic relationships between fossil and extant taxa. We exploit this statistical framework to investigate the internal consistency of these models by producing phylogenetic estimates of the age of each fossil in turn, within two rich and well-characterized datasets of fossil and extant species (penguins and canids). We find that the estimation accuracy of fossil ages is generally high with credible intervals seldom excluding the true age and median relative error in the two datasets of 5.7% and 13.2%, respectively. The median relative standard error (RSD) was 9.2% and 7.2%, respectively, suggesting good precision, although with some outliers. In fact, in the two datasets we analyse, the phylogenetic estimate of fossil age is on average less than 2 Myr from the mid-point age of the geological strata from which it was excavated. The high level of internal consistency found in our analyses suggests that the Bayesian statistical model employed is an adequate fit for both the geological and morphological data, and provides evidence from real data that the framework used can accurately model the evolution of discrete morphological traits coded from fossil and extant taxa. We anticipate that this approach will have diverse applications beyond divergence time dating, including dating fossils that are temporally unconstrained, testing of the \u2018morphological clock', and for uncovering potential model misspecification and/or data errors when controversial phylogenetic hypotheses are obtained based on combined divergence dating analyses. This article is part of the themed issue \u2018Dating species divergences using rocks and clocks\u2019.", "keyphrases": ["estimation", "fossil age", "morphological data", "tip"]}
{"id": "paleo.006122", "title": "Two ants (Insecta: Hymenoptera: Formicidae: Formicinae) from the Late Pliocene of Willershausen, Germany, with a nomenclatural note on the genus Camponotites", "abstract": "Two species of the genus Camponotites (Formicidae, Formicinae) are described from the Late Pliocene deposits of Willershausen, Lower Saxony, northern Germany: C. silvestris Steinbach, 1967, and C. steinbachi n. sp. The generic name Camponotites has been established for fossil (Tertiary) ants independently by Steinbach (Bericht der Naturhistorischen Gesellschaft zu Hannover 111:95-102, 1967) and by Dlussky (Trudy paleontologic \u02c7eskogo instituta, akademia \u02c6nauk SSSR, 1981), each for materials of different stratigraphical and geographical origin. Though poorly described, Camponotites Steinbach, 1967, and the single included (type) species C. silvestris Steinbach, 1967 (a monotypic species from the Late Pliocene of Willershausen), were based upon indication in the sense of the ICZN. Therefore, both the generic and specific names are valid and available. Camponotites Dlussky, 1981 (and its type species C. macropterus Dlus- sky, 1981) were certainly introduced correctly and are therefore available, too; but due to its homonymy the generic name is not valid. The revision shows that in this rare case both generic names are not only homonyms but also synonyms.", "keyphrases": ["late pliocene", "germany", "genus camponotites"]}
{"id": "paleo.007605", "title": "Hyoliths and small shelly fossils from the Lower Cambrian of North-East Greenland", "abstract": "The hyolith assemblage from the Lower Cambrian Bastion Formation of North-East Greenland is significant in that it contains several hyolith taxa that possess traits of both orders Hyolithida and Orthothecida. They possess morphological traits that seem to be characteristic of the ancestral forms of both groups. In addition, many hyolith taxa from this interval are globally distributed, supporting the notion that these fossils have potential as stratigraphic indicators. This assemblage contains genera and/or species seen in Australia, North America, the Siberian Platform, and South China. Hyoliths identified include the hyolithids Parkula bounites, Hyptiotheca karraculum, Microcornus eximius, M. petilus, Paracornus poulseni gen. et sp. nov., as well as Similotheca similis?, S. bastionensis sp. nov., and S. groenlandica sp. nov.; two opercula remain in open nomenclature. Orthothecids from this assemblage are one unnamed species each of Contitheca and Gracilitheca. Large, macro-sized hyoliths from the same formation described by Poulsen (1932) are mostly unidentifiable, although an operculum formerly identified as Hyolithes (Orthotheca) communis is reassigned to Hyptiotheca. Problematic organisms of uncertain affinity include Cupitheca holocyclata, Conotheca australiensis, an unnamed species of Coleolus, and the cap-shaped Cassitella baculata gen. et sp. nov. that may be an operculum of some as yet unknown organism. Missarzhevsky (1969) used Hyolithes (Orthotheca) bayonet var. groelandicus and H. (O.) bayonet var. longus as the basis for Lenatheca, but the specimens on which that genus is based are too poorly known for a proper diagnosis of Lenatheca.", "keyphrases": ["small shelly fossil", "north-east greenland", "same formation", "hyolith", "taxonomy"]}
{"id": "10.1073/pnas.0709378105", "title": "Increasing morphological complexity in multiple parallel lineages of the Crustacea", "abstract": "The prospect of finding macroevolutionary trends and rules in the history of life is tremendously appealing, but very few pervasive trends have been found. Here, we demonstrate a parallel increase in the morphological complexity of most of the deep lineages within a major clade. We focus on the Crustacea, measuring the morphological differentiation of limbs. First, we show a clear trend of increasing complexity among 66 free-living, ordinal-level taxa from the Phanerozoic fossil record. We next demonstrate that this trend is pervasive, occurring in 10 or 11 of 12 matched-pair comparisons (across five morphological diversity indices) between extinct Paleozoic and related Recent taxa. This clearly differentiates the pattern from the effects of lineage sorting. Furthermore, newly appearing taxa tend to have had more types of limbs and a higher degree of limb differentiation than the contemporaneous average, whereas those going extinct showed higher-than-average limb redundancy. Patterns of contemporary species diversity partially reflect the paleontological trend. These results provide a rare demonstration of a large-scale and probably driven trend occurring across multiple independent lineages and influencing both the form and number of species through deep time and in the present day.", "keyphrases": ["complexity", "crustacea", "differentiation"]}
{"id": "paleo.001605", "title": "Morphological and biomechanical disparity of crocodile-line archosaurs following the end-Triassic extinction", "abstract": "Mesozoic crurotarsans exhibited diverse morphologies and feeding modes, representing considerable ecological diversity, yet macroevolutionary patterns remain unexplored. Here, we use a unique combination of morphological and biomechanical disparity metrics to quantify the ecological diversity and trophic radiations of Mesozoic crurotarsans, using the mandible as a morpho-functional proxy. We recover three major trends. First, the diverse assemblage of Late Triassic crurotarsans was morphologically and biomechanically disparate, implying high levels of ecological variation; but, following the end-Triassic extinction, disparity declined. Second, the Jurassic radiation of marine thalattosuchians resulted in very low morphological disparity but moderate variation in jaw biomechanics, highlighting a hydrodynamic constraint on mandibular form. Third, during the Cretaceous terrestrial radiations of neosuchians and notosuchians, mandibular morphological variation increased considerably. By the Late Cretaceous, crocodylomorphs evolved a range of morphologies equalling Late Triassic crurotarsans. By contrast, biomechanical disparity in the Cretaceous did not increase, essentially decoupling from morphology. This enigmatic result could be attributed to biomechanical evolution in other anatomical regions (e.g. cranium, dentition or postcranium), possibly releasing the mandible from selective pressures. Overall, our analyses reveal a complex relationship between morphological and biomechanical disparity in Mesozoic crurotarsans that culminated in specialized feeding ecologies and associated lifestyles.", "keyphrases": ["biomechanical disparity", "end-triassic extinction", "dentition"]}
{"id": "paleo.005612", "title": "A new genus of Devonian tetrapod from North\u2010East Greenland, with new information on the lower jaw of Ichthyostega", "abstract": "Abstract:\u2002 A new genus and species of Devonian tetrapod has been identified from material collected in 1947 from the southern slope of Mt. Celsius, Ymer \u00d8, North\u2010East Greenland. The specimen preserves both lower jaws, partial palate, premaxillae and maxillae, with a natural mould of parts of the shoulder girdle. The new taxon, Ymeria denticulata, shows differences in dentition, skull ornament and lateral line expression from both Acanthostega and Ichthyostega, but it shows a closer resemblance to the latter. A cladistic analysis not only suggests that Ymeria lies adjacent to Ichthyostega on the tetrapod stem, but also reveals substantial topological instability. As the third genus and the fifth species of tetrapod identified from North\u2010East Greenland, it demonstrates the high diversity of Devonian tetrapods in that region.", "keyphrases": ["new genus", "tetrapod", "ichthyostega", "low jaw"]}
{"id": "paleo.006719", "title": "Short-Term Survival of Ammonites in New Jersey After the End-Cretaceous Bolide Impact", "abstract": "A section containing the Cretaceous/Paleogene (= Cretaceous/Tertiary) boundary in Monmouth County, New Jersey, preserves a record of ammonites extending from the end of the Cretaceous into possibly the beginning of the Danian. The section includes the upper part of the Tinton Formation and lower part of the Hornerstown Formation. The top of the Tinton Formation is represented by a richly fossiliferous unit (the Pinna Layer) that contains many bivalves in life position as well as ammonite jaws preserved inside body chambers. Ammonites include Pachydiscus (Neodesmoceras) mokotibensis, Sphenodiscus lobatus, Eubaculites carinatus, E. latecarinatus; Discoscaphites iris, D. sphaeroidalis; D. minardi, and D. jerseyensis. The Pinna Layer probably represents a relatively short interval of time lasting tens to hundreds of years; it is conformably overlain by the Burrowed Unit, which contains a single fragment of Discoscaphites sp. and several fragments of E. latecarinatus, as well as several isolated specimens of ammonite jaws including two of Eubaculites. Examination of the mode of preservation of the ammonites and jaws suggests that they were fossilized during deposition of the Burrowed Unit and were not reworked from older deposits. Based on the ammonites and dinoflagellates in the Pinna Layer and the Burrowed Unit, these strata traditionally would be assigned to the uppermost Maastrichtian, corresponding to calcareous nannofossil Subzone CC26b. However, a weak iridium anomaly (500\u2013600 pg/g) is present at the base of the Pinna Layer, which presumably represents the record of the bolide impact. Correlation with the iridium layer at the Global Stratotype Section and Point at El Kef, Tunisia, would, therefore, imply that these assemblages are actually Danian, provided that the iridium anomaly is in place and the ammonites and dinoflagellates are not reworked. If the iridium anomaly is in place, or even if it has migrated downward from the top of the Pinna Layer, the ammonites would have survived the impact at this site for a brief interval of time lasting from a few days to hundreds of years.", "keyphrases": ["ammonites", "new jersey", "maastrichtian"]}
{"id": "paleo.011422", "title": "Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama", "abstract": "Background As we know from modern species, nursery areas are essential shark habitats for vulnerable young. Nurseries are typically highly productive, shallow-water habitats that are characterized by the presence of juveniles and neonates. It has been suggested that in these areas, sharks can find ample food resources and protection from predators. Based on the fossil record, we know that the extinct Carcharocles megalodon was the biggest shark that ever lived. Previous proposed paleo-nursery areas for this species were based on the anecdotal presence of juvenile fossil teeth accompanied by fossil marine mammals. We now present the first definitive evidence of ancient nurseries for C. megalodon from the late Miocene of Panama, about 10 million years ago. Methodology/Principal Findings We collected and measured fossil shark teeth of C. megalodon, within the highly productive, shallow marine Gatun Formation from the Miocene of Panama. Surprisingly, and in contrast to other fossil accumulations, the majority of the teeth from Gatun are very small. Here we compare the tooth sizes from the Gatun with specimens from different, but analogous localities. In addition we calculate the total length of the individuals found in Gatun. These comparisons and estimates suggest that the small size of Gatun's C. megalodon is neither related to a small population of this species nor the tooth position within the jaw. Thus, the individuals from Gatun were mostly juveniles and neonates, with estimated body lengths between 2 and 10.5 meters. Conclusions/Significance We propose that the Miocene Gatun Formation represents the first documented paleo-nursery area for C. megalodon from the Neotropics, and one of the few recorded in the fossil record for an extinct selachian. We therefore show that sharks have used nursery areas at least for 10 millions of years as an adaptive strategy during their life histories.", "keyphrases": ["shark", "miocene", "tooth size"]}
{"id": "paleo.007633", "title": "The hydroid fossil record and analytical techniques for assessing the affinities of putative hydrozoans and possible hemichordates", "abstract": "Hydrozoan cnidarians are widespread in modern environments, but their polyps or hydroids, when not biomineralized, are generally rare in the fossil record. To assess the affinities of four hydrozoan taxa previously described on the basis of supposed fossils of non\u2010biomineralized hydroids, we re\u2010analysed the type specimens of these taxa using a combination of light and electron microscopic tools, including backscattered electron (BSE) scanning electron microscopy (SEM) and energy\u2010dispersive X\u2010ray spectroscopy (EDS). New morphological, ultrastructural and taphonomic data were generated for Archaeoantennularia byersi from the Devonian of Michigan, Archaeocryptolaria compacta from the Ordovician of Virginia, and Mazohydra megabertha and Drevotella proteana from the Carboniferous Mazon Creek Lagerst\u00e4tte of Illinois, which are preserved as carbonaceous fossils, aluminosilicate films and iron carbonate minerals in siderite concretions, respectively. In the context of these results, we provide a review of the fossil record of non\u2010biomineralized hydroids, describe possible biases and changes through time in their occurrence and preservation, and evaluate the criteria commonly used to identify and interpret their fossils. Although hydroids have been reported from Phanerozoic (particularly lower Palaeozoic) rocks around the world, many putative hydroids from the Palaeozoic are poorly substantiated and may actually be hemichordates. Indeed, none of the type specimens in this study represent unequivocal hydrozoans. As shown in BSE images, metatype specimens of A. byersi possess autothecae, fusellae, stolons, stolothecae and bithecae, which decisively indicate that they are dendroid graptolites rather than hydroids. The analyses yielded no evidence that A. compacta, Mazohydra and Drevotella are hydrozoans, as their holotypes lack the diagnostic morphological, taphonomic and ecological features characteristic of purported hydroid analogues. Consequently, our results suggest that many Palaeozoic hydroids may be hemichordates and that interpretations of hydroid fossils should be tested and refined using data collected via in situ analytical techniques like BSE\u2010SEM and EDS.", "keyphrases": ["analytical technique", "hydrozoan", "hemichordate", "fuselli", "sem-bse"]}
{"id": "10.1080/02724634.2017.1420661", "title": "Introduction to Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia", "abstract": "Citation for this article: Sidor, C. A., and S. J. Nesbitt. 2018. Introduction to vertebrate and climatic evolution in the Triassic rift basins of Tanzania and Zambia; pp. 1\u20137 in C. A. Sidor and S. J. Nesbitt (eds.), Vertebrate and Climatic Evolution in the Triassic Rift Basins of Tanzania and Zambia. Society of Vertebrate Paleontology Memoir 17. Journal of Vertebrate Paleontology 37 (6, Supplement).", "keyphrases": ["vertebrate", "climatic evolution", "tanzania"]}
{"id": "paleo.008866", "title": "Tooth chipping can reveal the diet and bite forces of fossil hominins", "abstract": "Mammalian tooth enamel is often chipped, providing clear evidence for localized contacts with large hard food objects. Here, we apply a simple fracture equation to estimate peak bite forces directly from chip size. Many fossil hominins exhibit antemortem chips on their posterior teeth, indicating their use of high bite forces. The inference that these species must have consumed large hard foods such as seeds is supported by the occurrence of similar chips among known modern-day seed predators such as orangutans and peccaries. The existence of tooth chip signatures also provides a way of identifying the consumption of rarely eaten foods that dental microwear and isotopic analysis are unlikely to detect.", "keyphrases": ["bite force", "fossil hominin", "hard food", "tooth chipping"]}
{"id": "10.26879/800", "title": "New reports of Paratethyan ostracods affinity from the Mediterranean Basin (Sicily, Italy)", "abstract": "During the late Messinian post evaporitic phase, in the eastern region between the Alps and the Aral Sea, the Paratethys was reduced to a number of large independent basins (Pannonian Basin, Pontic Basin and Caspian-Aral Basin) separated by vast continental regions. At the same time, in the Paleomediterranean region, discontinuous shallow-water basins were formed on the existing substrate. In these basins predominantly siliciclastic sediments were deposited consisting of gravels, sands, marls and silts, and containing continental oligohaline faunas. These sedimentary facies, which are largely exposed in Italy and in other Mediterranean regions, are called \"Lago-Mare\". These sediments overlapping the Messinian evaporitic layers in apparent conformity have already been reported from western Sicily. Now they have been sampled and analyzed in five different localities in eastern Sicily. These sedimentary facies are called \"Congeria\" strata (marl containing oligohaline faunas) and \"Arenazzolo\" (reddish arkosic sands containing brackish or freshwater ostracods). From these levels, which correspond to two different sedimentation environments, an oligotypic ostracod fauna was extracted consisting of species belonging to the genera Tyrrhenocythere, Loxoconcha and Cyprideis. Among them, Loxoconcha muelleri (Mehes, 1908) and Cyprideis anlavauxensis Carbonnel, 1979, are reported for the first time from Sicily. Two other species are new to science; one is described as Tyrrhenocythere pulcherrima sp. nov. herein, whereas, the other one is left in open nomenclature as Loxoconcha n. sp. Francesco Sciuto. Department of Biological, Geological and Environmental Science, University of Catania, Corso Italia 55, 95129 Catania, Italy. fsciuto@unict.it Angela Baldanza. Department of Physics and Geology, University of Perugia, Via Pascoli, 06123 Perugia, Italy. angela.baldanza@unipg.it Rim Temani. Office National des Mines, 24, rue de l'\u00e9nergie, 2035 La Charguia, Tunis, Tunisia. rim.temani@yahoo.fr Giovanni Privitera. Technical Study of Energy and Environment, Via Municipio, Misterbianco, Catania. giovpriv@tim.it http://zoobank.org/DA7F28E3-631B-4F93-B5B9-91A4B6CAB46E Sciuto, Francesco, Baldanza, Angela, Temani, Rim, and Privitera, Giovanni. 2018. New reports of Paratethyan ostracods affinity from the Mediterranean Basin (Sicily, Italy). Palaeontologia Electronica 21.1.12A 1-19. https://doi.org/10.26879/800 palaeo-electronica.org/content/2018/2174-paratethyan-ostracods Copyright: April 2018 Palaeontological Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ SCIUTO ET AL.: PARATETHYAN OSTRACODS", "keyphrases": ["paratethyan ostracod affinity", "ostracod affinity", "mediterranean basin"]}
{"id": "10.1080/14772010903537732", "title": "The higher-level phylogeny of Archosauria (Tetrapoda: Diapsida)", "abstract": "Crown group Archosauria, which includes birds, dinosaurs, crocodylomorphs, and several extinct Mesozoic groups, is a primary division of the vertebrate tree of life. However, the higher-level phylogenetic relationships within Archosauria are poorly resolved and controversial, despite years of study. The phylogeny of crocodile-line archosaurs (Crurotarsi) is particularly contentious, and has been plagued by problematic taxon and character sampling. Recent discoveries and renewed focus on archosaur anatomy enable the compilation of a new dataset, which assimilates and standardizes character data pertinent to higher-level archosaur phylogeny, and is scored across the largest group of taxa yet analysed. This dataset includes 47 new characters (25% of total) and eight taxa that have yet to be included in an analysis, and total taxonomic sampling is more than twice that of any previous study. This analysis produces a well-resolved phylogeny, which recovers mostly traditional relationships within Avemetatarsalia, places Phytosauria as a basal crurotarsan clade, finds a close relationship between Aetosauria and Crocodylomorpha, and recovers a monophyletic Rauisuchia comprised of two major subclades. Support values are low, suggesting rampant homoplasy and missing data within Archosauria, but the phylogeny is highly congruent with stratigraphy. Comparison with alternative analyses identifies numerous scoring differences, but indicates that character sampling is the main source of incongruence. The phylogeny implies major missing lineages in the Early Triassic and may support a Carnian-Norian extinction event.", "keyphrases": ["phylogeny", "archosauria", "avemetatarsalia", "terrestrial ecological niche"]}
{"id": "10.1126/science.aav2621", "title": "Early human dispersals within the Americas", "abstract": "Complex processes in the settling of the Americas The expansion into the Americas by the ancestors of present day Native Americans has been difficult to tease apart from analyses of present day populations. To understand how humans diverged and spread across North and South America, Moreno-Mayar et al. sequenced 15 ancient human genomes from Alaska to Patagonia. Analysis of the oldest genomes suggests that there was an early split within Beringian populations, giving rise to the Northern and Southern lineages. Because population history cannot be explained by simple models or patterns of dispersal, it seems that people moved out of Beringia and across the continents in a complex manner. Science, this issue p. eaav2621 Ancient genomes from the Americas show a complex genetic history giving rise to present-day diversity. INTRODUCTION Genetic studies of the Pleistocene peopling of the Americas have focused on the timing and number of migrations from Siberia into North America. They show that ancestral Native Americans (NAs) diverged from Siberians and East Asians ~23,000 years (~23 ka) ago and that a split within that ancestral lineage between later NAs and Ancient Beringians (ABs) occurred ~21 ka ago. Subsequently, NAs diverged into northern NA (NNA) and southern NA (SNA) branches ~15.5 ka ago, a split inferred to have taken place south of eastern Beringia (present-day Alaska and western Yukon Territory). RATIONALE Claims of migrations into the Americas by people related to Australasians or by bearers of a distinctive cranial morphology (\u201cPaleoamericans\u201d) before the divergence of NAs from Siberians and East Asians have created controversy. Likewise, the speed by which the Americas were populated; the number of basal divergences; and the degrees of isolation, admixture, and continuity in different regions are poorly understood. To address these matters, we sequenced 15 ancient human genomes recovered from sites spanning from Alaska to Patagonia; six are \u226510 ka old (up to ~18\u00d7 coverage). RESULTS All genomes are most closely related to NAs, including those of two morphologically distinct Paleoamericans and an AB individual. However, we also found that the previous model is just a rough outline of the peopling process: NA dispersal gave rise to more complex serial splitting and early population structure\u2014including that of a population that diverged before the NNA-SNA split\u2014as well as admixture with an earlier unsampled population, which is neither AB nor NNA or SNA. Once in the Americas, SNAs spread widely and rapidly, as evidenced by genetic similarity, despite differences in material cultural, between >10-ka-old genomes from North and South America. Soon after arrival in South America, groups diverged along multiple geographic paths, and before 10.4 ka ago, these groups admixed with a population that harbored Australasian ancestry, which may have been widespread among early South Americans. Later, Mesoamerican-related population(s) expanded north and south, possibly marking the movement of relatively small groups that did not necessarily swamp local populations genetically or culturally. CONCLUSION NAs radiated rapidly and gave rise to multiple groups, some visible in the genetic record only as unsampled populations. At different times these groups expanded to different portions of the continent, though not as extensively as in the initial peopling. That the early population spread widely and rapidly suggests that their access to large portions of the hemisphere was essentially unrestricted, yet there are genomic and archaeological hints of an earlier human presence. How these early groups are related or structured, particularly those with Australasian ancestry, remains unknown. Rapid expansion, compounded by the attenuating effect of distance and, in places, by geographic and social barriers, gave rise to complex population histories. These include strong population structure in the Pacific Northwest; isolation in the North American Great Basin, followed by long-term genetic continuity and ultimately an episode of admixture predating ~0.7 ka ago; and multiple independent, geographically uneven migrations into South America. One such migration provides clues of Late Pleistocene Australasian ancestry in South America, whereas another represents a Mesoamerican-related expansion; both contributed to present-day South American ancestry. NA dispersal and divergence over time. Schematic representation of the sampling points included in this study (circles) and our main conclusions (presented geographically and temporally). (A) Population history of the basal AB, NNA, and SNA branches in North America. kya, thousand years ago. (B) Early, rapid dispersal of SNAs across the continent (~14 ka ago). (C) Recent Mesoamerican-related expansion north and south. Arrows do not correspond to specific migration routes. Studies of the peopling of the Americas have focused on the timing and number of initial migrations. Less attention has been paid to the subsequent spread of people within the Americas. We sequenced 15 ancient human genomes spanning from Alaska to Patagonia; six are \u226510,000 years old (up to ~18\u00d7 coverage). All are most closely related to Native Americans, including those from an Ancient Beringian individual and two morphologically distinct \u201cPaleoamericans.\u201d We found evidence of rapid dispersal and early diversification that included previously unknown groups as people moved south. This resulted in multiple independent, geographically uneven migrations, including one that provides clues of a Late Pleistocene Australasian genetic signal, as well as a later Mesoamerican-related expansion. These led to complex and dynamic population histories from North to South America.", "keyphrases": ["dispersal", "americas", "initial peopling"]}
{"id": "paleo.001960", "title": "Ontogenetic stages of ceratopsian dinosaur Psittacosaurus\nin bone histology", "abstract": "The early ceratopsians Psittacosaurus and Protoceratops have provided important information on dinosaurian development because of abundant specimens of adults, subadults, juveniles, and even hatchlings. Here we present new data and methods for identifying key growth stages from bone histology. Previous studies on Psittacosaurus lujiatunensis from the Early Cretaceous Jehol Biota of China did not present in-depth analysis of growth patterns. Based on a histological study of 43 thin sections from 17 individuals of this species, we recognize four histological ontogenetic stages, i.e., hatchling, juvenile, sub-adult, and adult, but no fully-grown stage. We estimate life history and longevity from diaphyseal growth line counts and other features of histology. We show that P. lujiatunensis grew fast in early stages (hatchling, juvenile, and subadult), according to the density of vascular canals and the different type of bone tissue; the deposition of parallel fibred bone tissue in the outer cortex of the subadult stage indicates that growth rate was slowing down. We introduce a new graphical method to estimate the occurrence and volumes of vascular canals from thin sections more accurately than current two-dimensional approaches.", "keyphrases": ["bone histology", "psittacosaurus lujiatunensis", "ontogenetic stage"]}
{"id": "paleo.010844", "title": "Hominin and animal activities in the microstratigraphic record from Denisova Cave (Altai Mountains, Russia)", "abstract": "Denisova Cave in southern Siberia uniquely contains evidence of occupation by a recently discovered group of archaic hominins, the Denisovans, starting from the middle of the Middle Pleistocene. Artefacts, ancient DNA and a range of animal and plant remains have been recovered from the sedimentary deposits, along with a few fragmentary fossils of Denisovans, Neanderthals and a first-generation Neanderthal\u2013Denisovan offspring. The deposits also contain microscopic traces of hominin and animal activities that can provide insights into the use of the cave over the last 300,000 years. Here we report the results of a micromorphological study of intact sediment blocks collected from the Pleistocene deposits in the Main and East Chambers of Denisova Cave. The presence of charcoal attests to the use of fire by hominins, but other evidence of their activities preserved in the microstratigraphic record are few. The ubiquitous occurrence of coprolites, which we attribute primarily to hyenas, indicates that the site was visited for much of its depositional history by cave-dwelling carnivores. Microscopic traces of post-depositional diagenesis, bioturbation and incipient cryoturbation are observed in only a few regions of the deposit examined here. Micromorphology can help identify areas of sedimentary deposit that are most conducive to ancient DNA preservation and could be usefully integrated with DNA analyses of sediments at archaeological sites to illuminate features of their human and environmental history that are invisible to the naked eye.", "keyphrases": ["animal activity", "denisova cave", "hominin"]}
{"id": "10.1098/rstb.2021.0034", "title": "The evolution of biramous appendages revealed by a carapace-bearing Cambrian arthropod", "abstract": "Biramous appendages are a common feature among modern marine arthropods that evolved deep in arthropod phylogeny. The branched appendage of Cambrian arthropods has long been considered as the ancient biramous limb, sparking numerous investigations on its origin and evolution. Here, we report a new arthropod, Erratus sperare gen. et sp. nov., from the Lower Cambrian (Stage 3, 520 Ma) Chengjiang biota of Yunnan, China, with unique trunk appendages formed of lateral anomalocaridid-type flaps and ventral subconical endopods. These appendages represent an intermediate stage of biramous limb evolution, i.e. from \u2018two pairs of flap appendages' in radiodonts to \u2018flap + endopod\u2019 in Erratus, to \u2018exopod + endopod\u2019 in the rest of carapace-bearing arthropods that populate the basal region of the upper-stem lineage arthropods (deuteropods). The new species occupies a phylogenetic position at the first node closer to deuteropods than to radiodonts, and therefore pinpoints the earliest occurrence of the endopod within Deuteropoda. The primitive endopod is weakly sclerotized, and has unspecialized segments without endites or claw. The findings might support previous claims that the outer branch of the biramous limb of fossil marine arthropods, such as trilobites, is not a true exopod, but is instead a modified exite. This article is part of the theme issue \u2018The impact of Chinese palaeontology on evolutionary research\u2019.", "keyphrases": ["biramous appendage", "cambrian arthropod", "chengjiang biota"]}
{"id": "10.1126/science.1177265", "title": "The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary", "abstract": "The Fall of the Dinosaurs According to the fossil record, the rule of dinosaurs came to an abrupt end \u223c65 million years ago, when all nonavian dinosaurs and flying reptiles disappeared. Several possible mechanisms have been suggested for this mass extinction, including a large asteroid impact and major flood volcanism. Schulte et al. (p. 1214) review how the occurrence and global distribution of a global iridium-rich deposit and impact ejecta support the hypothesis that a single asteroid impact at Chicxulub, Mexico, triggered the extinction event. Such an impact would have instantly caused devastating shock waves, a large heat pulse, and tsunamis around the globe. Moreover, the release of high quantities of dust, debris, and gases would have resulted in a prolonged cooling of Earth's surface, low light levels, and ocean acidification that would have decimated primary producers including phytoplankton and algae, as well as those species reliant upon them. The Cretaceous-Paleogene boundary ~65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction.", "keyphrases": ["mass extinction", "cretaceous-paleogene boundary", "volcanism", "terrestrial ecosystem", "eruption"]}
{"id": "10.1080/03115518.2014.861732", "title": "New specimens of the logrunner Orthonyx kaldowinyeri (Passeriformes: Orthonychidae) from the Oligo-Miocene of Australia", "abstract": "Nguyen, J.M.T., Boles, W.E., Worthy, T.H., Hand, S.J. & Archer, M., 2014. New specimens of the logrunner Orthonyx kaldowinyeri (Passeriformes: Orthonychidae) from the Oligo-Miocene of Australia. Alcheringa 38, 000\u2013000. ISSN 0311\u20135518. Logrunners (Orthonychidae) are a family of ground-dwelling passerines that are endemic to the Australo-Papuan region. These peculiar birds are part of an ancient Australo-Papuan radiation that diverged basally in the oscine tree. Here we describe eight fossil tarsometatarsi of the logrunner Orthonyx kaldowinyeri, and a distal tibiotarsus tentatively assigned to this species from sites in the Riversleigh World Heritage Area, Australia. The new fossil material ranges in age from late Oligocene to early late Miocene, and extends the temporal range of the Orthonychidae into the late Oligocene; this is the geologically oldest record of the family. These specimens also include the oldest Cenozoic passerine fossils from Australia that can be confidently referred to an extant family. The distinctive features of the tarsometatarsus and tibiotarsus of extant logrunners, which are probably related to their unusual method of foraging, are also present in O. kaldowinyeri. Assuming that O. kaldowinyeri had vegetation requirements similar to those of extant logrunners, its presence in various Riversleigh sites provides clues about the palaeoenvironment of these sites. Jacqueline M.T. Nguyen [jacqueline.nguyen@unsw.edu.au] (author for correspondence), Suzanne J. Hand [s.hand@unsw.edu.au], Michael Archer [m.archer@unsw.edu.au], School of Biological, Earth and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Walter E. Boles [walter.boles@austmus.gov.au], Ornithology Section, Australian Museum, 6 College Street, Sydney, NSW 2010, Australia; Trevor H. Worthy [trevor.worthy@flinders.edu.au], School of Biological Sciences, Flinders University, Adelaide, SA 5001, Australia. Received 19.9.2013; revised 11.10.2013; accepted 25.10.2013 http://zoobank.org/urn:lsid:zoobank.org:pub:F4F6219A-22A3-4F6B-8AEE-2957A227C0E0", "keyphrases": ["passeriformes", "orthonychidae", "oligo-miocene"]}
{"id": "10.1080/08912963.2022.2035728", "title": "Palaeobiological inferences of the aetosaur Aetosauroides scagliai (Archosauria: Pseudosuchia) based on microstructural analyses of its appendicular bones", "abstract": "ABSTRACT Aetosaurs were a group of armoured pseudosuchians, recorded in most of the Upper Triassic continental deposits worldwide. Several osteohistological contributions of aetosaurs focused on their osteoderms, but rarely on appendicular bones. Here, we analyse the microstructure of the humerus, femur and tibia of Aetosauroides scagliai (specimens PVL 2073 [holotype] and PVL 2052). These exhibit cortical bone formed by highly vascularised fibrolamellar bone present in the inner portion of the cortex, mixed with scarce parallel-fibred bone. Also, they show parallel-fibred bone in the outermost portion of the cortex. A general growth pattern that includes a first rapid stage followed by a slow stage is reported. Nevertheless, the growth rate and the presence of parallel-fibred bone embedded in fibrolamellar bone layers recognise more variation within Aetosauria. The value of appendicular bones and osteoderms as age estimators is variable, the first being useful in early stages, and in late stages the osteoderms are better (based on the particular growth of osteoderms). Through morphological (neurocentral sutures) and histological (EFS absent) information, the holotype (PVL 2073) was recovered between juvenile and subadult stages. Using a statistical model that combines microanatomical and morphological data, a terrestrial lifestyle is inferred for Aetosauroides, which concur with previous analyses.", "keyphrases": ["aetosauroides scagliai", "appendicular bone", "pseudosuchian"]}
{"id": "10.5479/si.00810266.32.1", "title": "Permian Brachiopods of West Texas, VI", "abstract": "G. Arthur Cooper and Richard E. Grant. Permian Brachiopods of West Texas, I. Smithsonian Contributions to Paleobiology, number 14, 231 pages, 39 figures, 23 plates, 1972.\u2014The first of a projected six-part monograph on the brachiopods of the reference area for the North American Permian in the Glass, Guadalupe, Diablo, Delaware, Hueco, and Chinati Mountains of West Texas and adjacent New Mexico, this introductory volume recounts the history of geological work in the area, the development of the stratigraphic framework in the Wolf camp, Leonard, and Guadalupe Series, and the basis for age assignments. It also explains field and laboratory techniques for collecting and preparing silicified fossils by means of acid, and it presents detailed measurements and lithic descriptions of the stratigraphic units in each mountain range in terms of the current nomenclature. The paleoecologic implications of the various rock and fossil types are interpreted, and the problems concerning large scale conglomerates, bioherms, and shell heaps are considered. T h e faunal composition of each stratigraphic unit in each mountain range is set forth as documentation for a local zonation of the brachiopods, intra-regional correlations, and age determinations with reference to the worldwide time scale for the Permian. There are brief accounts of each locality from which fossils were obtained. The full locality listing and the literature cited for the entire monograph are included in the present volume. Plates and line drawings illustrate the techniques of collecting and preparing fossils and the nature of certain stratigraphic units and lithic types; they diagrammatically depict numerous cross sections and correlations. Detailed maps indicate the exact positions of collections of fossils in the Glass Mountains. Taxonomic descriptions will appear in subsequent volumes. Official publication date is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. Library of Congress Cataloging in Publication Data Cooper, Gustav Arthur, 1902Permian brachiopods of West Texas (Smithsonian contributions to paleobiology, no. 14) Bibliography: v. 1, p. 1. Brachiopoda, Fossil. 2. Paleontology\u2014Permian. 3. Paleontology\u2014Texas. I. Grant, Richard E., joint author. II. Title. III. Scries: Smithsonian Institution. Smithsonian contributions to paleobiology, no. 14 QE701.S56 no. 14 [QE796] 560'.8s [564'.8'097649] 72-4218 For sale by the Superintendent of Documents, U. S. Government Printing Office Washington, D. C 20402 Price |2.25 (paper cover)", "keyphrases": ["brachiopod", "west texas", "glass mountains"]}
{"id": "paleo.000589", "title": "Mollusks from the upper Shackleton Limestone (Cambrian Series 2), Central Transantarctic Mountains, East Antarctica", "abstract": "Abstract. \n An assemblage of Cambrian Series 2, Stages 3\u20134, conchiferan mollusks from the Shackleton Limestone, Transantarctic Mountains, East Antarctica, is formally described and illustrated. The fauna includes one bivalve, one macromollusk, and 10 micromollusks, including the first description of the species Xinjispira simplex Zhou and Xiao, 1984 outside North China. The new fauna shows some similarity to previously described micromollusks from lower Cambrian glacial erratics from the Antarctic Peninsula. The fauna,mainly composed of steinkerns, is relatively low diversity, but the presence of diagnostic taxa, including helcionelloid Davidonia rostrata (Zhou and Xiao, 1984), bivalve Pojetaia runnegari Jell, 1980, cambroclavid Cambroclavus absonus Conway Morris in Bengtson et al., 1990, and bradoriid Spinospitella coronata Skovsted et al., 2006, as well as the botsfordiid brachiopod Schizopholis yorkensis (Ushatinskaya and Holmer in Gravestock et al., 2001), in the overlying Holyoake Formation correlates the succession to the Dailyatia odyssei Zone (Cambrian Stages 3\u20134) in South Australia.", "keyphrases": ["shackleton limestone", "transantarctic mountains", "mollusk"]}
{"id": "10.1111/let.12060", "title": "Danian cold-water corals from the Baunekule facies, Faxe Formation, Denmark: a rare taphonomic window of a coral mound flank habitat", "abstract": "Well-preserved cold-water corals are comparatively rare in the fossil record. This is partly due to the very low fossilization potential of the predominantly aragonitic corals but also due to the fact that coral ecosystems of deep water are a geologically young development. A Middle Danian cold-water coral mound complex is well exposed in Faxe Quarry, Denmark. The coral mounds are intercalated with bryozoan mounds of various sizes and form the Faxe Formation. The coral limestone displays large variations in diagenesis, and this complicates the palaeoecological reconstructions. However, the Baunekule facies from the Faxe Formation contain a well-preserved originally aragonitic and calcitic fauna. The aragonitic skeletons have been recrystallized to calcite during early diagenesis and the excellent preservation makes taxonomic identifications straightforward. A diverse fauna of ten scleractinian coral species, nine stylasterine coral species and seven octocoral species has been described from the Baunekule facies. The fossil fauna represents an ecological niche between the dead coral framework and coral rubble on a flank of a growing Dendrophyllia coral mound with multiple colonization events. The diversity and relative abundance of the fossil scleractinian corals are comparable to the modern settings in the NE Atlantic and Mediterranean. The distribution and diversity of the octocorals and the stylasterine corals are suggested to represent coral gardens as described from modern setting in the NE Pacific. The presence of a diverse and abundant stylasterine fauna suggests a stable palaeoenvironment, probably in a bathymetric depth range of 200\u2013400\u00a0metre.", "keyphrases": ["cold-water coral", "coral", "deep water"]}
{"id": "10.1073/pnas.1207656110", "title": "Radiocarbon dating casts doubt on the late chronology of the Middle to Upper Palaeolithic transition in southern Iberia", "abstract": "It is commonly accepted that some of the latest dates for Neanderthal fossils and Mousterian industries are found south of the Ebro valley in Iberia at ca. 36 ka calBP (calibrated radiocarbon date ranges). In contrast, to the north of the valley the Mousterian disappears shortly before the Proto-Aurignacian appears at ca. 42 ka calBP. The latter is most likely produced by anatomically modern humans. However, two-thirds of dates from the south are radiocarbon dates, a technique that is particularly sensitive to carbon contaminants of a younger age that can be difficult to remove using routine pretreatment protocols. We have attempted to test the reliability of chronologies of 11 southern Iberian Middle and early Upper Paleolithic sites. Only two, Jarama VI and Zafarraya, were found to contain material that could be reliably dated. In both sites, Middle Paleolithic contexts were previously dated by radiocarbon to less than 42 ka calBP. Using ultrafiltration to purify faunal bone collagen before radiocarbon dating, we obtain ages at least 10 ka 14C years older, close to or beyond the limit of the radiocarbon method for the Mousterian at Jarama VI and Neanderthal fossils at Zafarraya. Unless rigorous pretreatment protocols have been used, radiocarbon dates should be assumed to be inaccurate until proven otherwise in this region. Evidence for the late survival of Neanderthals in southern Iberia is limited to one possible site, Cueva Ant\u00f3n, and alternative models of human occupation of the region should be considered.", "keyphrases": ["southern iberia", "pretreatment protocol", "radiocarbon"]}
{"id": "10.1080/03115518.2013.770221", "title": "Morphological comparisons of metacarpal I for Australovenator wintonensis and Rapator ornitholestoides: implications for their taxonomic relationships", "abstract": "WHITE, M.A., FALKINGHAM, P.L., COOK, A.G., HOCKNULL, S.A. & ELLIOTT, D.A., 2013. Morphological comparisons of metacarpal I for Australovenator wintonensis and Rapator ornitholestoides: implications for their taxonomic relationships. Alcheringa 37, 1 - 7. ISSN 0311-5518. Various comparisons of left metacarpal I of the Australovenator wintonensis holotype have been made with Rapator ornitholestoides. These specimens were identified as being morphologically more similar than either was to that of the neovenatorid Megaraptor namunhuaiquii. Owing to the poor preservation of A. wintonensis and R. ornitholestoides, distinct morphological separation between the two appeared minimal. The recent discovery of a near perfectly preserved right metacarpal I of A. wintonensis enables a direct and accurate comparison with R. ornitholestoides. Distinct morphological differences exist between the metacarpals of the two species. A re-evaluation of the age of the A. wintonensis holotype site (AODL 85 \u2018Matilda Site\u2019) with zircon dating reveals a maximum age of 95 Ma, 10 Ma younger than the Griman Creek Formation at Lightning Ridge, from which R. ornitholestoides was recovered. This age difference detracts from the probability that the specimens belong to the same genus. Matt A. White\u2217 [fossilised@hotmail.com], School of Engineering, The University of Newcastle, Callaghan, New South Wales 2308, Australia; Peter L. Falkingham\u2020 [pfalkingham@rvc.ac.uk], Department of Comparative Biomedical Sciences, Structure and Motion Laboratory, Royal Veterinary College, London, UK; Alex G. Cook [alex.cook@y7mail.com] and Scott A. Hocknull [scott.hocknull@qm.qld.gov.au], Ancient environments, Queensland Museum, Hendra, Queensland, 4011, Australia; David A. Elliott [david.elliott@aaod.com.au], Australian Age of Dinosaurs Museum of Natural History, The Jump Up, Winton, Queensland, 4735, Australia. \u2217Also affiliated with Australian Age of Dinosaurs Museum of Natural History, The Jump Up, Winton, Queensland 4735, Australia. \u2020Also affiliated with Department of Ecology and Evolutionary Biology, Division of Biology and Medicine, Brown University, USA. Received 22.9.2012; revised 13.1.2013; accepted 17.1.2013.", "keyphrases": ["metacarpal", "australovenator wintonensis", "taxonomic relationship", "australia"]}
{"id": "10.1098/rstb.2016.0489", "title": "History and contemporary significance of the Rhynie cherts\u2014our earliest preserved terrestrial ecosystem", "abstract": "The Rhynie cherts Unit is a 407 million-year old geological site in Scotland that preserves the most ancient known land plant ecosystem, including associated animals, fungi, algae and bacteria. The quality of preservation is astonishing, and the initial description of several plants 100 years ago had a huge impact on botany. Subsequent discoveries provided unparalleled insights into early life on land. These include the earliest records of plant life cycles and fungal symbioses, the nature of soil microorganisms and the diversity of arthropods. Today the Rhynie chert (here including the Rhynie and Windyfield cherts) takes on new relevance, especially in relation to advances in the fields of developmental genetics and Earth systems science. New methods and analytical techniques also contribute to a better understanding of the environment and its organisms. Key discoveries are reviewed, focusing on the geology of the site, the organisms and the palaeoenvironments. The plants and their symbionts are of particular relevance to understanding the early evolution of the plant life cycle and the origins of fundamental organs and tissue systems. The Rhynie chert provides remarkable insights into the structure and interactions of early terrestrial communities, and it has a significant role to play in developing our understanding of their broader impact on Earth systems. This article is part of a discussion meeting issue \u2018The Rhynie cherts: our earliest terrestrial ecosystem revisited\u2019.", "keyphrases": ["terrestrial ecosystem", "land", "late silurian", "vascular land plant", "diversification"]}
{"id": "paleo.001396", "title": "Time\u2010averaging and fidelity of modern death assemblages: building a taphonomic foundation for conservation palaeobiology", "abstract": "Ecosystems today are under growing pressure, with human domination at many scales. It is difficult, however, to gauge what has changed or been lost \u2013 and why \u2013 in the absence of data from periods before human activities. Actualistic taphonomic studies, originally motivated to understand preservational controls on deep\u2010time fossil records, are now providing insights into modern death assemblages as historical archives of present\u2010day ecosystems, turning taphonomy on its head. This article reviews the past 20 years of work on the temporal resolution and ability of time\u2010averaged skeletal assemblages to capture ecological information faithfully, focusing primarily on molluscs from soft\u2010sediment seafloors. Two promising arenas for \u2018applied taphonomy\u2019 are then highlighted: (1) using live\u2010dead mismatch \u2013 that is, observed discordance in the diversity, species composition, and distribution of living animals and co\u2010occurring skeletal remains \u2013 to recognize recent anthropogenic change, and (2) using time\u2010averaged death assemblages as windows into regional diversity and long\u2010term baselines, as a supplement or substitute for conventional live\u2010collected data. Meta\u2010analysis and modelling find that, in unaltered habitats, live\u2010dead differences in community\u2010level attributes can be generated largely or entirely by time\u2010averaging of natural spatial and temporal variability in living assemblages, on time frames consistent with the range of shell ages observed in death assemblages. Time\u2010averaging coarsens the temporal and spatial resolution of biological information in predictable ways; by comparison, taphonomic bias of information arising from differential preservation, production and transport of shells is surprisingly modest. Several challenges remain for basic taphonomic research, such as empirical and analytical methods of refining the temporal resolution of death assemblages; assessing the fate of resolution and fidelity with progressive burial; and expanding our understanding of the dynamics of skeletal accumulation in other groups and settings. Rather than shunning human\u2010impacted areas as inappropriate analogues of the deep past, we should capitalize on them to explore the fundamental controls on skeletal accumulation and to develop robust protocols for bringing time\u2010averaged death assemblages into the toolkits of conservation biology and environmental management.", "keyphrases": ["fidelity", "death assemblage", "accumulation", "time\u2010averaging", "fossil assemblage"]}
{"id": "paleo.007326", "title": "Origin of ecdysis: fossil evidence from 535-million-year-old scalidophoran worms", "abstract": "With millions of extant species, ecdysozoans (Scalidophora, Nematoida and Panarthropoda) constitute a major portion of present-day biodiversity. All ecdysozoans secrete an exoskeletal cuticle which must be moulted periodically and replaced by a larger one. Although moulting (ecdysis) has been recognized in early Palaeozoic panarthropods such as trilobites and basal groups such as anomalocaridids and lobopodians, the fossil record lacks clear evidence of ecdysis in early scalidophorans, largely because of difficulties in recognizing true exuviae. Here, we describe two types of exuviae in microscopic scalidophoran worms from the lowermost Cambrian Kuanchuanpu Formation (ca 535 Ma) of China and reconstruct their moulting process. These basal scalidophorans moulted in a manner similar to that of extant priapulid worms, extricating themselves smoothly from their old tubular cuticle or turning their exuviae inside out like the finger of a glove. This is the oldest record of moulting in ecdysozoans. We also discuss the origin of ecdysis in the light of recent molecular analyses and the significance of moulting in the early evolution of animals.", "keyphrases": ["ecdysis", "scalidophoran worm", "panarthropoda", "cambrian kuanchuanpu formation", "old record"]}
{"id": "paleo.003616", "title": "Reacquisition of the lower temporal bar in sexually dimorphic fossil lizards provides a rare case of convergent evolution", "abstract": "Temporal fenestration has long been considered a key character to understand relationships amongst reptiles. In particular, the absence of the lower temporal bar (LTB) is considered one of the defining features of squamates (lizards and snakes). In a re-assessment of the borioteiioid lizard Polyglyphanodon sternbergi (Cretaceous, North America), we detected a heretofore unrecognized ontogenetic series, sexual dimorphism (a rare instance for Mesozoic reptiles), and a complete LTB, a feature only recently recognized for another borioteiioid, Tianyusaurus zhengi (Cretaceous, China). A new phylogenetic analysis (with updates on a quarter of the scorings for P. sternbergi) indicates not only that the LTB was reacquired in squamates, but it happened independently at least twice. An analysis of the functional significance of the LTB using proxies indicates that, unlike for T. zhengi, this structure had no apparent functional advantage in P. sternbergi, and it is better explained as the result of structural constraint release. The observed canalization against a LTB in squamates was broken at some point in the evolution of borioteiioids, whereas never re-occuring in other squamate lineages. This case of convergent evolution involves a mix of both adaptationist and structuralist causes, which is unusual for both living and extinct vertebrates.", "keyphrases": ["lizard", "convergent evolution", "low temporal bar"]}
{"id": "paleo.002274", "title": "Carnivorous mammals from the middle Eocene Washakie Formation, Wyoming, USA, and their diversity trajectory in a post-warming world", "abstract": "The middle Eocene Washakie Formation of Wyoming, USA, provides a rare window, within a single depositional basin, into the faunal transition that followed the early Eocene warming events. Based on extensive examination, we report a minimum of 27 species of carnivorous mammals from this formation, more than doubling the previous taxic count. Included in this revised list are a new species of carnivoraform, Neovulpavus mccarrolli n. sp., and up to ten other possibly new taxa. Our cladistic analysis of early Carnivoraformes incorporating new data clarified the array of middle Eocene taxa that are closely related to crown-group Carnivora. These anatomically relatively derived carnivoraforms collectively had an intercontinental distribution in North America and east Asia, exhibiting notable variations in body size and dental adaptation. This time period also saw parallel trends of increase in body size and dental sectoriality in distantly related lineages of carnivores spanning a wide range of body sizes. A new, model-based Bayesian analysis of diversity dynamics accounting for imperfect detection revealed a high probability of substantial loss of carnivore species between the late Bridgerian and early Uintan North American Land Mammal 'Ages', coinciding with the disappearance of formerly common mammals such as hyopsodontids and adapiform primates. Concomitant with this decline in carnivore diversity, the Washakie vertebrate fauna underwent significant disintegration, as measured by patterns of coordinated detection of taxa at the locality level. These observations are consistent with a major biomic transition in the region in response to climatically induced opening-up of forested habitats. UUID: http://zoobank.org/9162f1a6-a12c-4d55-ba1d-dc66e8cda261", "keyphrases": ["wyoming", "usa", "carnivorous mammal"]}
{"id": "10.1093/molbev/msq247", "title": "Extended Y chromosome investigation suggests postglacial migrations of modern humans into East Asia via the northern route.", "abstract": "Genetic diversity data, from Y chromosome and mitochondrial DNA as well as recent genome-wide autosomal single nucleotide polymorphisms, suggested that mainland Southeast Asia was the major geographic source of East Asian populations. However, these studies also detected Central-South Asia (CSA)- and/or West Eurasia (WE)-related genetic components in East Asia, implying either recent population admixture or ancient migrations via the proposed northern route. To trace the time period and geographic source of these CSA- and WE-related genetic components, we sampled 3,826 males (116 populations from China and 1 population from North Korea) and performed high-resolution genotyping according to the well-resolved Y chromosome phylogeny. Our data, in combination with the published East Asian Y-haplogroup data, show that there are four dominant haplogroups (accounting for 92.87% of the East Asian Y chromosomes), O-M175, D-M174, C-M130 (not including C5-M356), and N-M231, in both southern and northern East Asian populations, which is consistent with the proposed southern route of modern human origin in East Asia. However, there are other haplogroups (6.79% in total) (E-SRY4064, C5-M356, G-M201, H-M69, I-M170, J-P209, L-M20, Q-M242, R-M207, and T-M70) detected primarily in northern East Asian populations and were identified as Central-South Asian and/or West Eurasian origin based on the phylogeographic analysis. In particular, evidence of geographic distribution and Y chromosome short tandem repeat (Y-STR) diversity indicates that haplogroup Q-M242 (the ancestral haplogroup of the native American-specific haplogroup Q1a3a-M3) and R-M207 probably migrated into East Asia via the northern route. The age estimation of Y-STR variation within haplogroups suggests the existence of postglacial (\u223c18 Ka) migrations via the northern route as well as recent (\u223c3 Ka) population admixture. We propose that although the Paleolithic migrations via the southern route played a major role in modern human settlement in East Asia, there are ancient contributions, though limited, from WE, which partly explain the genetic divergence between current southern and northern East Asian populations.", "keyphrases": ["modern human", "east asia", "northern route"]}
{"id": "paleo.001572", "title": "Effects of CO2 and Ocean Mixing on Miocene and Pliocene Temperature Gradients", "abstract": "Cenozoic climate changes have been linked to tectonic activity and variations in atmospheric CO2 concentrations. Here, we present Miocene and Pliocene sensitivity experiments performed with the climate model COSMOS. The experiments contain changes with respect to paleogeography, ocean gateway configuration, and atmospheric CO2 concentrations, as well as a range of vertical mixing coefficients in the ocean. For the mid\u2010Miocene, we show that the impact of ocean mixing on surface temperature is comparable to the effect of the possible range in reconstructed CO2 concentrations. In combination with stronger vertical mixing, relatively moderate CO2 concentrations of 450 ppmv enable global\u2010mean surface, deep\u2010water, and meridional temperature characteristics representative of mid\u2010Miocene Climatic Optimum (MMCO) reconstructions. The Miocene climate shows a reduced meridional temperature gradient and reduced seasonality. In the case of enhanced mixing, surface and deep ocean temperatures show significant warming of up to 5\u201310\u00b0C and an Arctic temperature anomaly of >12\u00b0C. In the Pliocene simulations, the impact of vertical mixing and CO2 is less important for the deep ocean, which we interpret as a different sensitivity dependence on the background state and mixed layer dynamics. We find a significant reduction in surface albedo and effective emissivity for either a high level of atmospheric CO2 or increased vertical mixing. Our mixing sensitivity experiments provide a warm deep ocean via ocean heat uptake. We propose that the mixing hypothesis can be tested by reconstructions of the thermocline and seasonal paleoclimate data indicating a lower seasonality relative to today.", "keyphrases": ["ocean mixing", "miocene", "warming", "arctic temperature anomaly"]}
{"id": "paleo.003568", "title": "Feeding preferences of Gomphotherium subtapiroideum (Proboscidea, Mammalia) from the Miocene of Sandelzhausen (Northern Alpine Foreland Basin, southern Germany) through life and geological time: evidence from dental microwear analysis", "abstract": "The objective of this study is to estimate changes in feeding preferences of the proboscidean species Gomphotherium subtapiroideum (Schlesinger 1917) by means of dental microwear analyses. The dietary changes are first evaluated through the ontogeny of this species, between juveniles and adults, and are then studied through geological time, from early Middle Miocene (MN5) to middle Late Miocene (MN8-9) localities of the German Molasse Basin. The microwear patterns of juvenile and adult individuals of G. subtapiroideum from Sandelzhausen (MN5) differ merely by the variable ''length of scratches'', emphasizing longer jaw movements during mastication in adults. The microwear signatures of G. subtapiroideum do not vary significantly between the two geological time periods studied, but reflect mixed feeding preferences in both cases. These results imply that, despite an important environmental change at that time (drying and opening), the ecology of G. subtapiroideum and, especially, its feeding habits were not affected. Its dental microwear pattern is then compared with those of other species of Proboscidea from the Middle-Late Miocene of Germany, namely Deinotherium giganteum and Gomphotherium steinheimense.", "keyphrases": ["germany", "geological time", "dental microwear analysis"]}
{"id": "paleo.010491", "title": "Old Lineages in a New Ecosystem: Diversification of Arcellinid Amoebae (Amoebozoa) and Peatland Mosses", "abstract": "Arcellinid testate amoebae (Amoebozoa) form a group of free-living microbial eukaryotes with one of the oldest fossil records known, yet several aspects of their evolutionary history remain poorly understood. Arcellinids occur in a range of terrestrial, freshwater and even brackish habitats; however, many arcellinid morphospecies such as Hyalosphenia papilio are particularly abundant in Sphagnum-dominated peatlands, a relatively new ecosystem that appeared during the diversification of Sphagnum species in the Miocene (5\u201320 Myr ago). Here, we reconstruct divergence times in arcellinid testate amoebae after selecting several fossils for clock calibrations and then infer whether or not arcellinids followed a pattern of diversification that parallels the pattern described for Sphagnum. We found that the diversification of core arcellinids occurred during the Phanerozoic, which is congruent with most arcellinid fossils but not with the oldest known amoebozoan fossil (i.e. at ca. 662 or ca. 750 Myr). Overall, Sphagnum and the Hyalospheniidae exhibit different patterns of diversification. However, an extensive molecular phylogenetic analysis of distinct clades within H. papilio species complex demonstrated a correlation between the recent diversification of H. papilio, the recent diversification of Sphagnum mosses, and the establishment of peatlands.", "keyphrases": ["new ecosystem", "diversification", "amoebozoa"]}
{"id": "paleo.002203", "title": "Early Jurassic diversification of pycnodontiform fishes (Actinopterygii, Neopterygii) after the end-Triassic extinction event: evidence from a new genus and species, Grimmenodon aureum", "abstract": "ABSTRACT \n A new genus and species of pycnodontiform fishes, Grimmenodon aureum, from marginal marine, marinebrackish lower Toarcian (Harpoceras exaratum ammonite subzone) clay deposits of Grimmen in northeastern Germany is described. The single specimen represents a diagnostic left prearticular dentition characterized by unique tooth arrangement and ornamentation patterns. Grimmenodon aureum, gen. et sp. nov., is the second unambiguously identified pycnodontiform species from the Early Jurassic, in addition to Eomesodon liassicus from the early Lower Jurassic of western Europe. We also report an indeterminate pycnodontiform tooth crown from the upper Pliensbachian (Pleuroceras apyrenum ammonite subzone) of the same site. The material expands the Early Jurassic range of pycnodontiforms significantly northwards and confirms their presence before and immediately following the onset of the Toarcian Oceanic Anoxic Event (T-OAE) in the marginal marine ecosystems south of the Fennoscandian Shield. Moreover, the new records indicate that the Early Jurassic diversity of pycnodontiform fishes was greater than previously assumed and probably equaled that of the Late Triassic. Therefore, it is hypothesized that the Triassic-Jurassic mass extinction event did not affect pycnodontiform fishes significantly. Micro-computed tomography was used to study the internal anatomy of the prearticular of Grimmenodon aureum, gen. et sp. nov. Our results show that no replacement teeth were formed within the tooth-bearing bone but rather were added posteriorly to functional teeth.", "keyphrases": ["pycnodontiform fish", "new genus", "grimmenodon aureum", "upper pliensbachian"]}
{"id": "10.1080/03115510802417695", "title": "Fossil wood of the Mimosoideae from the early Paleocene of Patagonia, Argentina", "abstract": "Brea, M., Zamuner, A.B., Matheos, S.D., Iglesias, A. & Zucol, A.F., December, 2008. Fossil wood of the Mimosoideae from the early Paleocene of Patagonia, Argentina. Alcheringa 32, 427\u2013441. ISSN 0311-5518. An anatomically preserved mature stem from the Salamanca Formation (early Paleocene) at Palacio de Los Loros, central Patagonia, Argentina, is described and assigned to Paracacioxylon frenguellii sp. nov. The material was preserved by siliceous permineralization and shows features of the secondary xylem typical of subfamily Mimosoideae. This species represents the oldest record of the genus and of the Leguminosae along the western border of Gondwana, and is the world's second oldest record of Leguminosae wood. The species is characterized by ring-porous to semi-ring-porous vessels that are solitary, in multiples of 2\u20134 and clustered, simple perforation plates, alternate and vestured inter-vessel pitting, homocellular 1\u20136 seriate rays, tyloses, crystals and diffuse apotracheal, vasicentric paratracheal and confluent axial parenchyma. Paracacioxylon frenguellii has anatomical similarities to Acacia Miller. The presence of Paracacioxylon frenguellii associated with pulvinate leaves suggests that the legumes might have been a component of mesothermal forests developed along the western margin of the Golfo San Jorge Basin during the early Paleocene.", "keyphrases": ["mimosoideae", "paleocene", "salamanca formation", "fossil wood"]}
{"id": "10.1080/02724634.1994.10011537", "title": "Megalancosaurus, a possibly arboreal archosauromorph (Reptilia) from the Upper Triassic of northern Italy", "abstract": "ABSTRACT The Late Triassic reptile Megalancosaurus preonensis Calzavara et al., 1980, was previously known from a single incomplete specimen collected from the Norian \u201cDolomia di Forni\u201d at the locality of val Preone, near Ampezzo Carnico (Udine, Friuli, northern Italy). The recent discovery of a new specimen in the Zorzino Limestone, also of Norian age, at a locality near Zogno (Bergamo Prealps, Lombardy, northern Italy) allows a more complete description of the skeleton of Megalancosaurus preonensis and attribution of three other specimens, previously interpreted as juvenile individuals of Drepanosaurus unguicaudatus to the same taxon. Megalancosaurus was a small reptile with a high degree of adaptation toward arboreal life, and is probably an archosauromorph.", "keyphrases": ["archosauromorph", "northern italy", "megalancosaurus"]}
{"id": "paleo.006391", "title": "A new phylogenetic hypothesis of turtles with implications for the timing and number of evolutionary transitions to marine lifestyles in the group", "abstract": "Evolutionary transitions to marine habitats occurred frequently among Mesozoic reptiles. Only one such clade survives to the present: sea turtles (Chelonioidea). Other marine turtles originated during the Mesozoic, but uncertain affinities of key fossils have obscured the number of transitions to marine life, and the timing of the origin of marine adaptation in chelonioids. Phylogenetic studies support either a highly\u2010inclusive chelonioid total\u2010group including fossil marine clades from the Jurassic and Cretaceous (e.g. protostegids, thalassochelydians, sandownids) or a less inclusive chelonioid total\u2010group excluding those clades. Under this paradigm, these clades belong outside Cryptodira, and represent at least one additional evolutionary transition to marine life in turtles. We present a new phylogenetic hypothesis informed by high resolution computed tomographic data of living and fossil taxa. Besides a well\u2010supported Chelonioidea, which includes protostegids, we recover a previously unknown clade of stem\u2010group turtles, Angolachelonia, which includes the Late Jurassic thalassochelydians, and the Cretaceous\u2013Palaeogene sandownids. Accounting for the Triassic Odontochelys, our results indicate three independent evolutionary transitions to marine life in non\u2010pleurodiran turtles (plus an additional two\u2010three in pleurodires). Among all independent origins of marine habits, a pelagic ecology only evolved once, among chelonioids. All turtle groups that independently invaded marine habitats in the Jurassic\u2013Cretaceous (chelonioids, angolachelonians, bothremydid pleurodires) survived the Cretaceous\u2013Palaeogene mass extinction event. This highlights extensive survival of marine turtles compared to other marine reptiles. Furthermore, deeply\u2010nested clades such as chelonioids are found by the middle Early Cretaceous, suggesting a rapid diversification of crown\u2010group turtles during the Early Cretaceous.", "keyphrases": ["new phylogenetic hypothesis", "turtle", "evolutionary transition", "chelonioidea", "ecology"]}
{"id": "paleo.009506", "title": "Illustrating phylogenetic placement of fossils using RoguePlots: An example from ichneumonid parasitoid wasps (Hymenoptera, Ichneumonidae) and an extensive morphological matrix", "abstract": "The fossil record constitutes the primary source of information about the evolutionary history of extant and extinct groups, and many analyses of macroevolution rely on fossils that are accurately placed within phylogenies. To avoid misinterpretation of the fossil record, especially by non-palaeontologists, the proper assessment and communication of uncertainty in fossil placement is crucial. We here use Bayesian morphological phylogenetics to evaluate the classifications of fossil parasitoid wasps (Hymenoptera, Ichneumonidae) and introduce \u2018RoguePlots\u2019 to illustrate placement uncertainty on the phylogeny of extant taxa. Based on an extensive, newly constructed morphological matrix of 222 characters in 24 fossil and 103 extant taxa, we test three different aspects of models of morphological evolution. We find that a model that includes ordered characters, among-character rate variation, and a state-space restricted to observed states achieves the highest marginal likelihoods. The individual RoguePlots reveal large differences in confidence in the placement of the different fossils and allow some refinements to their classification: Polyhelictes bipolarus and Ichninsum appendicrassum are moved from an uncertain subfamily placement to Pimplinae, Plectiscidea lanhami is transferred to Allomacrus in Cylloceriinae (Allomacrus lanhami, comb. nov.), Lithotorus cressoni is moved from Diplazontinae to Orthocentrinae, and we note uncertainty in the generic placements of Rhyssella? vera and Xanthopimpla? messelensis. We discuss potential artefacts that might result in biased posterior probabilities in Bayesian morphological phylogenetic analyses, pertaining to character and taxon sampling, fossilization biases, and model misspecification. Finally, we suggest future directions both in ichneumonid palaeontology and in the way RoguePlots can improve both assessment and representation of placement uncertainty, both in fossils and other rogue taxa.", "keyphrases": ["parasitoid wasp", "hymenoptera", "morphological matrix", "taxon sampling"]}
{"id": "paleo.012464", "title": "Powered flight in hatchling pterosaurs: evidence from wing form and bone strength", "abstract": "Competing views exist on the behaviour and lifestyle of pterosaurs during the earliest phases of life. A \u2018flap-early\u2019 model proposes that hatchlings were capable of independent life and flapping flight, a \u2018fly-late\u2019 model posits that juveniles were not flight capable until 50% of adult size, and a \u2018glide-early\u2019 model requires that young juveniles were flight-capable but only able to glide. We test these models by quantifying the flight abilities of very young juvenile pterosaurs via analysis of wing bone strength, wing loading, wingspan and wing aspect ratios, primarily using data from embryonic and hatchling specimens of Pterodaustro guinazui and Sinopterus dongi. We argue that a young Sinopterus specimen has been mischaracterised as a distinct taxon. The humeri of pterosaur juveniles are similar in bending strength to those of adults and able to withstand launch and flight; wing size and wing aspect ratios of young juveniles are also in keeping with powered flight. We therefore reject the \u2018fly-late\u2019 and \u2018glide-early\u2019 models. We further show that young juveniles were excellent gliders, albeit not reliant on specialist gliding. The wing forms of very young juveniles differ significantly from larger individuals, meaning that variation in speed, manoeuvrability, take-off angle and so on was present across a species as it matured. Juveniles appear to have been adapted for flight in cluttered environments, in contrast to larger, older individuals. We propose on the basis of these conclusions that pterosaur species occupied distinct niches across ontogeny.", "keyphrases": ["flight", "pterosaur", "wing form"]}
{"id": "10.1017/jpa.2017.65", "title": "Appraisal of the fossil record of Homarus (nephropid lobster), with description of a new species from the upper Oligocene of Hungary and remarks on the status of Hoploparia", "abstract": "Abstract. \n The fossil record of the clawed lobster genus, Homarus, is appraised. The taxonomic history of Homarus and Hoploparia is summarized, and a list of species recognized for each is provided. A tabulation of all fossil species of the family Nephropidae permits assessment of nephropid species diversity through time. A new species of Homarus, H. hungaricus, is recorded from the upper Oligocene (Chattian) M\u00e1ny Formation at M\u00e1ny, northern Hungary. The species is known by a single specimen consisting of a partial cephalothorax, a pleon minus telson, and partial chelipeds. Homarus is now known by two extant species (H. americanus and H. gammarus) and six fossil taxa, one of Early Cretaceous (Albian; H. benedeni) and five of Cenozoic age (H. hungaricus n. sp., H. klebsi, H. lehmanni, H. morrisi, and H. percyi). The new fossil Homarus differs from modern congeners in aspects of carapace and pleon ornamentation and, especially, cutter claw shape. This is the fourth Oligocene occurrence of a nephropid species; all are Homarus and all are from Western Europe. Homarus makes its appearance in the fossil record in the Early Cretaceous (Albian) and then is not known again until the Paleogene, despite the fact that nephropid lobsters in general are well known from the Late Cretaceous. Nephropid lobsters are better known from the Cretaceous than from the Cenozoic. Both raw species numbers and numbers corrected (normalized) for epicontinental sea coverage show that shelf-dwelling nephropid lobsters were most diverse during the Late Cretaceous.", "keyphrases": ["nephropid lobster", "upper oligocene", "hoploparia"]}
{"id": "paleo.000517", "title": "Romundina and the evolutionary origin of teeth", "abstract": "Theories on the origin of vertebrate teeth have long focused on chondrichthyans as reflecting a primitive condition\u2014but this is better informed by the extinct placoderms, which constitute a sister clade or grade to the living gnathostomes. Here, we show that \u2018supragnathal\u2019 toothplates from the acanthothoracid placoderm Romundina stellina comprise multi-cuspid teeth, each composed of an enameloid cap and core of dentine. These were added sequentially, approximately circumferentially, about a pioneer tooth. Teeth are bound to a bony plate that grew with the addition of marginal teeth. Homologous toothplates in arthrodire placoderms exhibit a more ordered arrangement of teeth that lack enameloid, but their organization into a gnathal, bound by layers of cellular bone associated with the addition of each successional tooth, is the same. The presence of enameloid in the teeth of Romundina suggests that it has been lost in other placoderms. Its covariation in the teeth and dermal skeleton of placoderms suggests a lack of independence early in the evolution of jawed vertebrates. It also appears that the dentition\u2014manifest as discrete gnathal ossifications\u2014was developmentally discrete from the jaws during this formative episode of vertebrate evolution.", "keyphrases": ["placoderm", "tooth", "bony plate", "romundina", "dermal jaw bone"]}
{"id": "10.1111/syen.12230", "title": "Antiquity of cleptoparasitism among bees revealed by morphometric and phylogenetic analysis of a Paleocene fossil nomadine (Hymenoptera: Apidae)", "abstract": "Cleptoparasitism is a way of life involving the theft of resources by one animal from another. This behaviour occurs in many bee tribes but its origin and evolution remain obscure, particularly owing to the relative scarcity of bees in the fossil record. Hitherto, no fossil evidence has been recorded to trace the origin of cleptoparasitim among bees. In the current study, we present the first cleptoparasitic bee fossil, providing analyses of its taxonomic affinities and a complete description. The specimen also happens to be one of the earliest bee fossils, having been discovered in the spongo\u2010diatomitic volcanic paleolake of Menat (Paleocene) in France. We employed geometric morphometrics of the forewing shape to assess the taxonomic affinities of the fossil with modern apoid tribes. Our dataset included 979 specimens representing 50 tribes and 225 extant species. Based on linear and geometric morphometrics, we demonstrate that the fossil's forewing shape is similar to that of Apidae, and particularly to that of the tribe Epeolini (Nomadinae). The fossil is described as Paleoepeolus micheneri gen.n., sp.n. and provides the first direct evidence on the antiquity of cleptoparasitism among bees.", "keyphrases": ["cleptoparasitism", "bee", "apidae", "forewing shape"]}
{"id": "10.1126/science.aar5452", "title": "Modeling the ecology and evolution of biodiversity: Biogeographical cradles, museums, and graves", "abstract": "Simulating South American biodiversity The emergence, distribution, and extinction of species are driven by interacting factors\u2014spatial, temporal, physical, and biotic. Rangel et al. simulated the past 800,000 years of evolution in South America, incorporating these factors into a spatially explicit dynamic model to explore the geographical generation of diversity. Their simulations, based on a paleoclimate model on a 5\u00b0 latitude-longitude scale, result in shifting maps of speciation, persistence, and extinction (or cradles, museums, and graves). The simulations culminate in a striking resemblance to contemporary distribution patterns across the continent for birds, mammals, and plants\u2014despite having no target patterns and no empirical data parameterizing them. Science, this issue p. eaar5452 Mechanistic simulations of climate dynamics, speciation, and adaptive evolution yield realistic geographical patterns of biodiversity. INTRODUCTION Individual processes that shape geographical patterns of biodiversity are increasingly understood, but their complex interactions on broad spatial and temporal scales remain beyond the reach of analytical models and traditional experiments. To meet this challenge, we built a spatially explicit, mechanistic model that simulates the history of life on the South American continent, driven by modeled climates of the past 800,000 years. Operating at the level of geographical ranges of populations, our simulations implemented adaptation, geographical range shifts, range fragmentation, speciation, long-distance dispersal, competition between species, and extinction. Only four parameters were required to control these processes (dispersal distance, evolutionary rate, time for speciation, and intensity of competition). To assess the effects of topographic heterogeneity, we experimentally smoothed the climate maps in some treatments. RATIONALE The simulations had no target patterns. Instead, the study took a fundamental approach, relying on the realism of the modeled ecological and evolutionary processes, theoretical derivations of parameter values, and the climatic and topographic drivers to produce meaningful biogeographical patterns. The model encompassed only the Late Quaternary (last 800,000 years), with its repeated glacial-interglacial cycles, beginning at a time when South America was already populated with a rich biota, comprising many distinct lineages. Nonetheless, current consensus holds that the contemporary flora and vertebrate fauna of South America include numerous lineages that have undergone rapid diversification during the Quaternary, particularly in the Andes. In our model, over the course of each simulation, a complete phylogeny emerged from a single founding species. On the basis of the full historical records for each species range, at each 500-year interval, we recorded spatial and temporal patterns of speciation (\u201ccradles\u201d), persistence (\u201cmuseums\u201d), extinction (\u201cgraves\u201d), and species richness. RESULTS Simulated historical patterns of species richness, as recorded by maps of the richness of persistent (museum) species, proved quite successful in capturing the broad features of maps of contemporary species richness for birds, mammals, and plants. Factorial experiments varying parameter settings and initial conditions revealed the relative impact of the evolutionary and ecological processes that we modeled, as expressed in spatial and temporal patterns of cradles, museums, graves, and species richness. These patterns were most sensitive to the geographical location of the founding species and to the rate of evolutionary adaptation. Experimental topographic smoothing confirmed a crucial role for climate heterogeneity in the diversification of clades, especially in the Andes. Analyses of temporal patterns of speciation (cradles) and extinction (graves) emerging from the simulations implicated Quaternary glacial-interglacial cycles as drivers of both diversification and extinction on a continental scale. CONCLUSION Our biogeographical simulations were constructed from the bottom up, integrating mechanistic models of key ecological and evolutionary processes, following well-supported, widely accepted explanations for how these processes work in nature. Despite being entirely undirected by any target pattern of real-world species richness and covering only a tiny slice of the past, surprisingly realistic continental and regional patterns of species richness emerged from the model. Our simulations confirm a powerful role for adaptive niche evolution, in the context of diversification and extinction driven by topography and climate. Observed species richness versus modeled (simulated) richness. Upper map: Contemporary South American bird richness (2967 species). Lower map: Simulated spatial pattern for the cumulative richness of persistent (museum) species, arising from the model. The map show results averaged over all parameter values for an Atlantic Rainforest founder, excluding the climate-smoothing experimental treatments. Simulated species richness is highly correlated with observed species richness for birds (r2 = 0.6337). Individual processes shaping geographical patterns of biodiversity are increasingly understood, but their complex interactions on broad spatial and temporal scales remain beyond the reach of analytical models and traditional experiments. To meet this challenge, we built a spatially explicit, mechanistic simulation model implementing adaptation, range shifts, fragmentation, speciation, dispersal, competition, and extinction, driven by modeled climates of the past 800,000 years in South America. Experimental topographic smoothing confirmed the impact of climate heterogeneity on diversification. The simulations identified regions and episodes of speciation (cradles), persistence (museums), and extinction (graves). Although the simulations had no target pattern and were not parameterized with empirical data, emerging richness maps closely resembled contemporary maps for major taxa, confirming powerful roles for evolution and diversification driven by topography and climate.", "keyphrases": ["biodiversity", "museum", "grave", "south america", "planet"]}
{"id": "10.1111/j.1474-919X.2009.00939.x", "title": "Gyrfalcon Falco rusticolus post\u2010glacial colonization and extreme long\u2010term use of nest\u2010sites in Greenland", "abstract": "Gyrfalcons Falco rusticolus use the same nest-sites over long periods of time, and in the cold dry climate of Greenland, guano and other nest debris decay slowly. Nineteen guano samples and three feathers were collected from 13 Gyrfalcon nests with stratified faecal accumulation in central-west and northwest Greenland. Samples were 14 C dated, with the oldest guano sample dating to c. 2740\u20102360 calendar years (cal yr) before present (BP) and three others were probably > 1000 cal yr BP. Feather samples ranged from 670 to 60 cal yr BP. Although the estimated age of material was correlated with sample depth, both sample depth and guano thickness gave a much less reliable prediction of sample age than use of radiocarbon dating on which the margin of error was less. Older samples were obtained from sites farther from the current Greenland Ice Sheet and at higher elevations, while younger samples were closer to the current ice sheet and at lower elevations. Values for d 13 C showed that Gyrfalcons nesting farther from the Greenland Ice Sheet had a more marine diet, whereas those nesting closer to the ice sheet (= further inland) fed on a more terrestrial diet. The duration of nest-site use by Gyrfalcons is a probable indicator of both the time at which colonization occurred and the palaeoenvironmental conditions and patterns of glacial retreat. Nowhere before has such extreme long-term to present use of raptor nest-sites been documented.", "keyphrases": ["colonization", "greenland", "gyrfalcon"]}
{"id": "10.1126/science.aaa6635", "title": "Paleontological baselines for evaluating extinction risk in the modern oceans", "abstract": "Recognizing the threat of additive risk Humans are accelerating the extinction rates of species in both terrestrial and marine environments. However, species extinctions have occurred across time for a variety of other reasons. Finnegan et al. looked at the extinction rates across marine genera (groups of species) over the past 23 million years to determine intrinsic extinction rates and what traits or regions correspond to the highest rates. Combining patterns of intrinsic extinction with regions of high anthropogenic threat revealed taxa and areas, particularly in the tropics, where the risk of extinction will be especially high. Science, this issue p. 567 Fossils reveal patterns of extinction in marine species, past and present. Marine taxa are threatened by anthropogenic impacts, but knowledge of their extinction vulnerabilities is limited. The fossil record provides rich information on past extinctions that can help predict biotic responses. We show that over 23 million years, taxonomic membership and geographic range size consistently explain a large proportion of extinction risk variation in six major taxonomic groups. We assess intrinsic risk\u2014extinction risk predicted by paleontologically calibrated models\u2014for modern genera in these groups. Mapping the geographic distribution of these genera identifies coastal biogeographic provinces where fauna with high intrinsic risk are strongly affected by human activity or climate change. Such regions are disproportionately in the tropics, raising the possibility that these ecosystems may be particularly vulnerable to future extinctions. Intrinsic risk provides a prehuman baseline for considering current threats to marine biodiversity.", "keyphrases": ["baseline", "extinction risk", "marine specie", "biodiversity"]}
{"id": "10.1029/2020PA004061", "title": "Millennial\u2010Scale Changes in Bottom Water Temperature and Water Mass Exchange Through the Fram Strait 79\u00b0N, 63\u201013 ka", "abstract": "The Svalbard margin, in the eastern Fram Strait with its high sediment accumulation, form a key area for the reconstruction of water mass and heat exchange between the North Atlantic and Arctic Ocean in relation to abrupt climate changes as seen in glacial Greenland Interstadial and Greenland Stadial (GI\u2010GS) events. Here, we present a bottom water temperature (BWT) record from the northern Nordic Seas (79\u00b0N) at 1,273 m water depth based on benthic foraminiferal Mg/Ca. The BWT reconstructions, combined with benthic foraminiferal stable isotopes, benthic foraminiferal fauna compositions and ice\u2010rafted debris (IRD), reveal at least two distinctive scenarios for the GI\u2010GS events during the last glacial period (13\u201363 ka). During GIs, conditions were similar to modern with high productivity, low BWT and deep convection. During GS6, GS8, and GS15 and during Heinrich Stadials (HSs), BWT increased up to 5\u00b0C \u00b1 1\u00b0C generally concomitant with low planktic and benthic \u03b418O. Our results suggest, that during some GSs and HSs, deep water generation was reduced, allowing the subsurface Atlantic water (AW) to thicken and deepen down to at least the core site depth. A strong halocline during HSs and GSs prevented heat release from the subsurface AW, which we can now trace from 45\u00b0N in the North Atlantic to the Arctic Ocean >79\u00b0N. Surfacing of the salty Atlantic subsurface water preconditioned the Nordic seas for convection. Release of the subsurface heat from this vast reservoir must have contributed to the large and abrupt atmospheric warmings at the start of GIs.", "keyphrases": ["bottom water temperature", "fram strait", "arctic ocean"]}
{"id": "10.1029/2004PA001071", "title": "A Pliocene\u2010Pleistocene stack of 57 globally distributed benthic \u03b418O records", "abstract": "[1]\u00a0We present a 5.3-Myr stack (the \u201cLR04\u201d stack) of benthic \u03b418O records from 57 globally distributed sites aligned by an automated graphic correlation algorithm. This is the first benthic \u03b418O stack composed of more than three records to extend beyond 850 ka, and we use its improved signal quality to identify 24 new marine isotope stages in the early Pliocene. We also present a new LR04 age model for the Pliocene-Pleistocene derived from tuning the \u03b418O stack to a simple ice model based on 21 June insolation at 65\u00b0N. Stacked sedimentation rates provide additional age model constraints to prevent overtuning. Despite a conservative tuning strategy, the LR04 benthic stack exhibits significant coherency with insolation in the obliquity band throughout the entire 5.3 Myr and in the precession band for more than half of the record. The LR04 stack contains significantly more variance in benthic \u03b418O than previously published stacks of the late Pleistocene as the result of higher-resolution records, a better alignment technique, and a greater percentage of records from the Atlantic. Finally, the relative phases of the stack's 41- and 23-kyr components suggest that the precession component of \u03b418O from 2.7\u20131.6 Ma is primarily a deep-water temperature signal and that the phase of \u03b418O precession response changed suddenly at 1.6 Ma.", "keyphrases": ["stack", "benthic \u03b418o record", "age model", "benthic stack"]}
{"id": "paleo.003249", "title": "The endemic radiodonts of the Cambrian Stage 4 Guanshan biota of South China", "abstract": "The Guanshan Biota (South China, Cambrian, Stage 4) contains a diverse assemblage of biomineralizing and non-biomineralizing animals. Sitting temporally between the Stage 3 Chengjiang and Wuliuan Kaili Biotas, the Guanshan Biota contains numerous fossil organisms that are exclusive to this exceptional deposit. The Guanshan Konservat-Lagerst\u00e4tte is also unusual amongst Cambrian strata that preserve non-biomineralized material, as it was deposited in a relatively shallow water setting. In this contribution we double the diversity of radiodonts known from the Guanshan Biota from two to four, and describe the second species of Paranomalocaris . In addition, we report the first tamisiocaridid from South China, and confirm the presence of a tetraradial oral cone bearing small and large plates in \u201cAnomalocaris\u201d kunmingensis , the most abundant radiodont from the deposit. All four radiodont species, and three genera, are apparently endemic to the Guanshan Biota. When considered in the wider context of geographically and temporally comparable radiodont faunas, endemism in Guanshan radiodonts is most likely a consequence of the shallower and more proximal environment in which they lived. The strong coupling of free-swimming radiodonts and benthic communities underlines the complex relationship between the palaeobiogeographic and environmental distributions of prey and predators. This local adaptation of radiodonts to their prey is highlighted by the frontal appendage morphology of the two species of Paranomalocaris , apparently specialised to different feeding modes, while the recognition of the limited geographic range of some radiodont faunas highlights the importance of exploring as many deposits as possible to fully understand this group.", "keyphrases": ["radiodont", "guanshan biota", "south china"]}
{"id": "paleo.003541", "title": "The hyoid arch and braincase anatomy of Acanthodes support chondrichthyan affinity of \u2018acanthodians\u2019", "abstract": "Solving the evolutionary relationships of the acanthodians is one of the key problems in reconstructing ancestral anatomical conditions for the jawed vertebrates (gnathostomes). Current debate concerns whether acanthodians are an assemblage of stem chondrichthyans, or a more generalized grade encompassing some early stem osteichthyans. The skull anatomy of Acanthodes bronni has been pivotal in these debates, owing to tension between chondrichthyan- and osteichthyan-like models of reconstruction. We use computed tomography scanning and traditional palaeontological techniques to resolve the long-standing debate about the anatomy of the jaw suspension. We establish the correct length of the hyomandibula and show that it attaches to a process on the ventrolateral angle of the braincase below the jugular vein groove. This condition corresponds precisely to that in chondrichthyans. This character represents an unambiguously optimized synapomorphy with chondrichthyans given current gnathostome phylogenies, corroborating the growing consensus of the chondrichthyan affinity of acanthodians.", "keyphrases": ["chondrichthyan affinity", "acanthodian", "stem osteichthyan"]}
{"id": "10.1111/j.1461-0248.2007.01020.x", "title": "Evolution and the latitudinal diversity gradient: speciation, extinction and biogeography.", "abstract": "A latitudinal gradient in biodiversity has existed since before the time of the dinosaurs, yet how and why this gradient arose remains unresolved. Here we review two major hypotheses for the origin of the latitudinal diversity gradient. The time and area hypothesis holds that tropical climates are older and historically larger, allowing more opportunity for diversification. This hypothesis is supported by observations that temperate taxa are often younger than, and nested within, tropical taxa, and that diversity is positively correlated with the age and area of geographical regions. The diversification rate hypothesis holds that tropical regions diversify faster due to higher rates of speciation (caused by increased opportunities for the evolution of reproductive isolation, or faster molecular evolution, or the increased importance of biotic interactions), or due to lower extinction rates. There is phylogenetic evidence for higher rates of diversification in tropical clades, and palaeontological data demonstrate higher rates of origination for tropical taxa, but mixed evidence for latitudinal differences in extinction rates. Studies of latitudinal variation in incipient speciation also suggest faster speciation in the tropics. Distinguishing the roles of history, speciation and extinction in the origin of the latitudinal gradient represents a major challenge to future research.", "keyphrases": ["latitudinal diversity gradient", "speciation", "tropic", "high rate"]}
{"id": "paleo.003641", "title": "Fossil amphibians and reptiles from the Neogene locality of Maramena (Greece), the most diverse European herpetofauna at the Miocene/Pliocene transition boundary", "abstract": "We herein describe the fossil amphibians and reptiles from the Neogene (latest Miocene or earliest Pliocene; MN 13/14) locality of Maramena, in northern Greece. The herpetofauna is shown to be extremely diverse, comprising at least 30 different taxa. Amphibians include at least six urodelan (Cryptobranchidae indet., Salamandrina sp., Lissotriton sp. [Lissotriton vulgaris group], Lissotriton sp., Ommatotriton sp., and Salamandra sp.), and three anuran taxa (Latonia sp., Hyla sp., and Pelophylax sp.). Reptiles are much more speciose, being represented by two turtle (the geoemydid Mauremys aristotelica and a probable indeterminate testudinid), at least nine lizard (Agaminae indet., Lacertidae indet., ?Lacertidae indet., aff. Palaeocordylus sp., ?Scincidae indet., Anguis sp., five morphotypes of Ophisaurus, Pseudopus sp., and at least one species of Varanus), and 10 snake taxa (Scolecophidia indet., Periergophis micros gen. et sp. nov., Paraxenophis spanios gen. et sp. nov., Hierophis cf. hungaricus, another distinct \u201ccolubrine\u201d morphotype, Natrix aff. rudabanyaensis, and another distinct species of Natrix, Naja sp., cf. Micrurus sp., and a member of the \u201cOriental Vipers\u201d complex). The autapomorphic features and bizarre vertebral morphology of Periergophis micros gen. et sp. nov. and Paraxenophis spanios gen. et sp. nov. render them readily distinguishable among fossil and extant snakes. Cryptobranchids, several of the amphibian genera, scincids, Anguis, Pseudopus, and Micrurus represent totally new fossil occurrences, not only for the Greek area, but for the whole southeastern Europe. The four different types of serration within the Varanus teeth from Maramena raise questions on the taxonomic importance or the variability of this feature. The large number of distinct amphibian and reptile taxa in Maramena makes this Greek locality by far the most diverse and speciose among all European localities across the latest Miocene and earliest Pliocene. An estimation of the palaeoprecipitation value of the locality is provided. The biogeographic origins of the Maramena herpetofauna are not fully resolved, though certain of its elements were previously only known from the early and middle Miocene of Central Europe. GEORGALIS ET AL.: FOSSIL HERPETOFAUNA MARAMENA 2 Georgios L. Georgalis. Dipartimento di Scienze della Terra, Universit\u00e0 di Torino, Via Valperga Caluso 35, 10125 Torino, Italy. dimetrodon82@gmail.com Department of Geosciences, University of Fribourg / Freiburg, Chemin du Mus\u00e9e 6, 1700 Fribourg, Switzerland. Department of Ecology, Laboratory of Evolutionary Biology, Faculty of Natural Sciences, Comenius University in Bratislava, Mlynsk\u00e1 dolina, 84215 Bratislava, Slovakia. Andrea Villa. Bayerische Staatssammlung f\u00fcr Pal\u00e4ontologie und Geologie, Richard-Wagner-Stra\u00dfe 10, 80333 Munich, Germany. a.villa@unito.it Dipartimento di Scienze della Terra, Universit\u00e0 di Torino, Via Valperga Caluso 35, 10125 Torino, Italy. Martin Ivanov. Department of Geological Sciences, Faculty of Science, Masaryk University, Kotl\u00e1\u0159sk\u00e1 2, 611 37 Brno, Czech Republic. mivanov@sci.muni.cz Davit Vasilyan. JURASSICA Museum, Fontenais 21, 2900 Porrentruy, Switzerland. Department of Geosciences, University of Fribourg / Freiburg, Chemin du Mus\u00e9e 6, 1700 Fribourg, Switzerland. davitvasilyan@gmail.com Massimo Delfino. Dipartimento di Scienze della Terra, Universit\u00e0 di Torino, Via Valperga Caluso 35, 10125 Torino, Italy. massimo.delfino@unito.it Institut Catal\u00e0 de Paleontologia Miquel Crusafont, Universitat Aut\u00f2noma de Barcelona, Edifici ICTA-ICP, Carrer de les Columnes s/n, Campus de la UAB, 08193 Cerdanyola del Vall\u00e8s, Barcelona, Spain.", "keyphrases": ["reptile", "miocene", "pliocene", "fossil amphibian", "south-eastern european region"]}
{"id": "10.3389/feart.2022.833379", "title": "Reproducible Digital Restoration of Fossils Using Blender", "abstract": "Digital restoration of fossils based on computed tomographic (CT) imaging and other scanning technologies has become routine in paleontology. Digital restoration includes the retrodeformation and reconstruction of a fossil specimen. The former involves modification of the original 3D model to reverse post-mortem brittle and plastic deformation; and the latter involves the infilling of fractures, addition of missing pieces, and smoothing of the mesh surface. The restoration process often involves digital editing of the specimen in ways that are difficult to document and reproduce. To record all actions taken during the digital restoration of a fossil, we outline a workflow that generates both the restored bone and the sequence of steps involved in its retrodeformation and reconstruction. Our method can also generate an animation showing the transformation of the original digital model into its final form. We applied this method to a dorsal rib and frontal bone of a small-bodied Jurassic-age armored dinosaur from Africa, the digital restoration of which engaged all modalities of deformation (translation, rotation, scaling, distortion) and reconstruction (fracture infilling, adding missing bone, surface smoothing). Each bone was CT-scanned, segmented, and imported into Blender, an open-source 3D-graphics animation program. Blender has an animation tool called an \u201carmature\u201d that allows for precise control over portions of a surface mesh while keeping a record of manipulations. To retrodeform a fossil, an armature is created and then linked, or \u201crigged,\u201d to the fossil in order to control the displacement and distortion of its fragments. After using the armature to perform retrodeformation, we use Blender to record the movement and distortion of each fragment and also record reconstructive modifications. By ensuring documentation and reproducibility in an open-source program, our workflow and output open a window onto the heretofore largely hidden process of digital restoration in paleontology.", "keyphrases": ["digital restoration", "blender", "manipulation"]}
{"id": "paleo.009079", "title": "The potential of sedimentary ancient DNA for reconstructing past sea ice evolution", "abstract": "Sea ice is a crucial component of the Arctic climate system, yet the tools to document the evolution of sea ice conditions on historical and geological time scales are few and have limitations. Such records are essential for documenting and understanding the natural variations in Arctic sea ice extent. Here we explore sedimentary ancient DNA (aDNA), as a novel tool that unlocks and exploits the genetic (eukaryote) biodiversity preserved in marine sediments specifically for past sea ice reconstructions. Although use of sedimentary aDNA in paleoceanographic and paleoclimatic studies is still in its infancy, we use here metabarcoding and single-species quantitative DNA detection methods to document the sea ice conditions in a Greenland Sea marine sediment core. Metabarcoding has allowed identifying biodiversity changes in the geological record back to almost ~100,000 years ago that were related to changing sea ice conditions. Detailed bioinformatic analyses on the metabarcoding data revealed several sea-ice-associated taxa, most of which previously unknown from the fossil record. Finally, we quantitatively traced one known sea ice dinoflagellate in the sediment core. We show that aDNA can be recovered from deep-ocean sediments with generally oxic bottom waters and that past sea ice conditions can be documented beyond instrumental time scales. Our results corroborate sea ice reconstructions made by traditional tools, and thus demonstrate the potential of sedimentary aDNA, focusing primarily on microbial eukaryotes, as a new tool to better understand sea ice evolution in the climate system.", "keyphrases": ["sedimentary ancient dna", "dna", "sea ice evolution", "marine sediment"]}
{"id": "10.1029/2005PA001153", "title": "Slow dynamics of the Northern Hemisphere glaciation", "abstract": "[1]\u00a0Unraveling the dynamics of the Northern Hemisphere glaciation (NHG) in the Pliocene is a key step toward a quantitative theory of the climate transition from a greenhouse to an icehouse world. Extracting the ice volume signal from marine oxygen isotope (\u03b418O) records corrupted with \u201ctemperature noise\u201d can be accomplished using statistical time series analysis. We use 45 \u03b418O records from benthic and planktonic foraminifera and globally distributed sites to reconstruct the dynamics of NHG initiation. We compare \u03b418O amplitudes with those of temperature proxy records and estimate a global ice volume\u2013related increase of 0.4\u2030, equivalent to an overall sea level lowering of 43 m. We find the NHG started significantly earlier than previously assumed, as early as 3.6 Ma, and ended at 2.4 Ma. This long-term increase points to slow, tectonic forcing such as closing of ocean gateways or mountain building as the root cause of the NHG.", "keyphrases": ["dynamic", "northern hemisphere glaciation", "pliocene", "climate transition"]}
{"id": "paleo.008672", "title": "Dental enamel ultrastructure in Ochotona and Prolagus (Mammalia: Lagomorpha: Ochotonidae) from three late Miocene localities in Ukraine", "abstract": "The comparison of the dental enamel of late Miocene ochotonids from the Ukraine shows only very subtle differences. The ultrastructure of premolars, molars, and incisors of pikas: Ochotona and Prolagus (Lagomorpha, Ochotonidae) from three localities (Popovo 3, MN 11; Verkhnya Krynytsya 2, MN 12; Lobkove, MN 12/13) is mainly multilayered. In cheek teeth it is composed of a radial (up to 60% of total enamel thickness) and an irregular layer (up to 40%). There is almost no difference in the enamel ultrastructure between remains of different geological age and tooth position (premolars, molars). However, the lower incisor of Ochotona differs from the upper one in having a radial enamel and a HSB layer, whereas the upper have a radial and a tangential enamel. Minor differences between the various species of Ochotona and Prolagus could be recognised in the arrangement of the prisms.", "keyphrases": ["enamel ultrastructure", "lagomorpha", "ochotonidae"]}
{"id": "10.1017/S0094837300008988", "title": "Clonal growth, algal symbiosis, and reef formation by corals", "abstract": "The occurrence of zooxanthellae in Recent scleractinian corals is strongly correlated with their growth form, corallite size, and degree of morphological integration of corallites. The great majority of zooxanthellate corals are multiserial with small, highly integrated corallites, whereas most corals lacking zooxanthellae are solitary or uniserial colonial forms with large, poorly integrated corallites. Beginning in the Jurassic, fossil scleractinian faunas are morphologically similar to Recent faunas dominated by zooxanthellate species, strongly implying that most scleractinians contained zooxanthellae by that time. Evidence for Siluro\u2013Devonian tabulates and Triassic scleractinians is equivocal but still suggests the presence of zooxanthellae in these corals. In contrast, morphological evidence suggests that rugosan corals lacked zooxanthellae. Most populations of Recent zooxanthellate corals contribute to reef formation, but many do not. Similarly, fossil corals interpreted to contain zooxanthellae on morphological grounds did not always form reefs. Recent reef formation depends upon a host of environmental factors that have little to do with the possession of zooxanthellae per se. Coral morphology should be a better predictor of the presence of zooxanthellae in fossil corals than their association with reefs.", "keyphrases": ["reef formation", "coral", "growth form", "zooxanthellate coral"]}
{"id": "paleo.005877", "title": "The hatching mechanism of 130\u2010million\u2010year\u2010old insects: an association of neonates, egg shells and egg bursters in Lebanese amber", "abstract": "Hatching is a pivotal moment in the life of most animals. Diverse chemical, behavioural and mechanical methods have evolved in metazoans to break the egg membranes. Among them, many arthropod and vertebrate embryos hatch using ephemeral, frequently convergent structures known as egg bursters. However, the evolutionary processes by which hatching mechanisms and related embryonic structures became established in deep time are poorly understood due to a nearly complete absence from the fossil record. Herein we describe an exceptional c. 130\u2010million\u2010year\u2010old association in Lebanese amber composed of multiple neonate green lacewing larvae, Tragichrysa ovoruptora gen. et sp. nov. (Neuroptera, Chrysopoidea), and conspecific egg remains. Egg bursters with a serrated blade bearing a short process are attached to three longitudinally split egg shells. Embryos of extant green lacewing relatives (Chrysopidae) utilize this egg burster morphotype to open a vertical slit on the egg, after which the burster is moulted and left joined to the empty egg shell. Additionally, the new larval species has extremely elongate dorsal tubercles, an adaptation to carry exogenous debris for protection and camouflage also known from other Cretaceous chrysopoids but absent in modern relatives. The present discovery demonstrates that the hatching mechanism of modern green lacewings was established in the chrysopoid lineage by the Early Cretaceous and proves through direct fossil evidence how some morphological traits related to hatching and linked behaviours, at least in insect embryos, have been subject to a high degree of evolutionary conservatism.", "keyphrases": ["insect", "egg shell", "lebanese amber", "chrysopoidea"]}
{"id": "10.1080/02724634.1999.10011178", "title": "A nomenclature for vertebral laminae in sauropods and other saurischian dinosaurs", "abstract": "ABSTRACT The vertebrae of sauropods are characterized by numerous bony struts that connect the costovertebral and intervertebral articulations, centrum, and neural spine of the presacral, sacral, and anterior caudal vertebrae. A nomenclature for sauropod vertebral laminae is proposed that: 1) utilizes the morphological landmarks connected by the laminae (rather than their spatial orientation); and 2) provides the same name for serial homologues. This landmark-based nomenclature for vertebral laminae, which establishes the first criterion of homology (similarity), is the first step towards interpreting their phylogenetic significance. Nineteen different neural arch laminae are identified in sauropods, although all are never present in a single vertebra. Vertebral laminae can be divided into four regional categories, with each distinct lamina abbreviated with a simple four-letter acronym: diapophyseal laminae; parapophyseal laminae; zygapophyseal laminae; and spinal laminae. The distribution of neural arch ...", "keyphrases": ["nomenclature", "vertebral laminae", "sauropod", "neural arch"]}
{"id": "10.1111/j.1475-4983.2010.00995.x", "title": "High concentration of long\u2010snouted beaked whales (genus Messapicetus) from the Miocene of Peru", "abstract": "Abstract:\u2002 Eight skulls of beaked whales (Cetacea, Odontoceti, Ziphiidae), in six cases associated with elements of the mandible, were collected from a limited area (about 1.5\u2003km2) and roughly from the same stratigraphic horizon at Cerro Colorado, 35\u2003km south\u2010south\u2010west of the city of Ica (Peru), where the late Middle Miocene basal strata of the Pisco Formation crop out. They represent the highest concentration reported of fossil Ziphiidae. These finely preserved Cerro Colorado fossils are described and assigned to a new species Messapicetus gregarius, together with another specimen collected from sediments of the same age at Cerro la Bruja (33\u2003km south\u2010east to Cerro Colorado). Messapicetus gregarius shares with M. longirostris Bianucci, Landini and Varola, 1992 (Tortonian of Italy), an extremely elongated rostrum, but is clearly different from the Italian species in the more distinct maxillary tubercle and prominential notch, the more robust premaxillary crest, and the abrupt ventrolateral descent of the medial margin of the maxilla from the vertex. A parsimony analysis reveals that Messapicetus belongs to a basal clade, which includes other ziphiids with a dorsally closed mesorostral groove and prenarial basin. The high concentration of specimens belonging to the same species (some of them tentatively identified as adult males and females), combined with the presence of a calf, supports the hypothesis of site fidelity; these cetaceans might have lived in a limited region for a long period for both breeding and feeding. Besides the eight specimens of M. gregarius, strata at Cerro Colorado include many other cetacean remains (with several specimens of the pontoporiid Brachydelphis including a foetus), pinnipeds, turtles, fishes, and birds.", "keyphrases": ["whale", "ziphiidae", "high concentration"]}
{"id": "10.1098/rsbl.2019.0447", "title": "A palaeolimnological perspective to understand regime-shift dynamics in two Yangtze-basin lakes", "abstract": "Natural and human disturbances have caused widespread regime shifts in shallow lakes of the lower Yangtze basin (LYB, China) resulting in a severe decline of ecosystem services. Improved understanding of the relationship between environmental forcing and ecosystem response, and the mechanisms behind regime shifts has significant implications for management. However, the patterns of these regime shifts and the underlying internal mechanisms are less known. In this study, two typical lakes (Chaohu and Zhangdu) from the LYB were selected to determine the trajectories of ecological regime shifts, both of which transitioned from vegetation- to plankton-dominated states several decades ago. Ecological trajectories since the 1900s in both lakes were reconstructed using palaeolimnological proxies, mainly diatom assemblages. Although results show that regime shifts occurred in both lakes in the 1970s and the 1950s, respectively, their inherent mechanisms were different. In Lake Zhangdu, altered hydrological conditions pushed the ecosystem across an ecological threshold, providing an example of a driver-mediated regime shift. In Lake Chaohu, ongoing nutrient loading influenced ecosystem processes and drove the lake to an alternative stable state, potentially presenting an example of a critical transition after a loss of resilience. This research indicates that palaeolimnological perspectives can provide insights into regime shift changes, as well as important information regarding which restoration methods should be tailored to individual lakes.", "keyphrases": ["palaeolimnological perspective", "lake", "diatom assemblage"]}
{"id": "paleo.009537", "title": "Barium distributions in teeth reveal early life dietary transitions in primates", "abstract": "Early life dietary transitions reflect fundamental aspects of primate evolution and are important determinants of health in contemporary human populations1,2. Weaning is critical to developmental and reproductive rates; early weaning can have detrimental health effects but enables shorter inter-birth intervals, which influences population growth3. Uncovering early life dietary history in fossils is hampered by the absence of prospectively-validated biomarkers that are not modified during fossilisation4. Here we show that major dietary shifts in early life manifest as compositional variations in dental tissues. Teeth from human children and captive macaques, with prospectively-recorded diet histories, demonstrate that barium (Ba) distributions accurately reflect dietary transitions from the introduction of mother\u2019s milk and through the weaning process. We also document transitions in a Middle Palaeolithic juvenile Neanderthal, which shows a pattern of exclusive breastfeeding for seven months, followed by seven months of supplementation. After this point, Ba levels in enamel returned to baseline prenatal levels, suggesting an abrupt cessation of breastfeeding at 1.2 years of age. Integration of Ba spatial distributions and histological mapping of tooth formation enables novel studies of the evolution of human life history, dietary ontogeny in wild primates, and human health investigations through accurate reconstructions of breastfeeding history.", "keyphrases": ["dietary transition", "primate", "neanderthal", "tooth", "barium"]}
{"id": "10.1029/96pa02877", "title": "Changes in the Western Boundary Undercurrent Outflow since the Last Glacial Maximum, from smectite/illite ratios in deep Labrador Sea sediments", "abstract": "High-resolution mineralogical studies were performed on late glacial and deglacial sediments from two deep piston cores from the Labrador Sea, located at the inlet (SW Greenland Rise) and outlet (Labrador Rise) of the Western Boundary Undercurrent (WBUC) gyre. At the two sites, smectites transported from the eastern Iceland and Irminger basins by the WBUC are observed. Clay mineral changes are used as proxies for the paleointensity reconstruction of the WBUC. On the Greenland Rise, a clay mineral index (smectite/illite (S/I) ratio) is defined. A S/I ratio of \u223c1 characterized the Last Glacial Maximum. It increased after \u223c17 ka. and reached a maximum value of 4 during the early Holocene. The mineralogical changes are gradual and do not show any reversal during the Younger Dryas. This pattern, which is confirmed by first-order estimations of smectite and illite fluxes, suggests gradually increasing sedimentary fluxes and WBUC intensity since the Last Glacial Maximum. A peak in the velocity of the WBUC at \u223c9 ka, as recorded by clay assemblages, is consistent with other regional studies based on pollen, foraminifera, or grain-size measurements. A massive dilution of smectites by illite and chlorite (S/I \u2248 3) occurs at \u223c8.5 ka. It corresponds to a period of rapid sediment accumulation and reflects an intensified illite-rich detrital supply by meltwaters from the southern Greenland Ice Margin. On the Labrador Rise, the smectite content varies between 20 and 60% with no obvious trend through time. The mineralogical composition is strongly influenced by ice-rafted deposition and by the abundance of fast deposit units (cf. Heinrich layers in the North Atlantic) which contain abundant detrital carbonates spilled-over from the North-West Atlantic Mid-Ocean Channel. In such layers, smectites are present but are diluted by the addition of illites, chlorites, and kaolinites. This provides evidence for a discrete and continuous WBUC supply of fine particles from the Irminger and Iceland Basins as far as the southeastern part of the Labrador Basin. Early deglacial smectite-rich layers (up to 60%) are also observed at this site. They indicate an increase in the outflow of the WBUC at \u223c13.5 ka. (Bolling-Allerod), as previously reported from grain size or foraminiferal assemblage studies.", "keyphrases": ["glacial maximum", "smectite", "labrador sea"]}
{"id": "10.1111/pala.12508", "title": "Evolution of ecospace occupancy by Mesozoic marine tetrapods", "abstract": "Ecology and morphology are different, and yet in comparative studies of fossil vertebrates the two are often conflated. The macroevolution of Mesozoic marine tetrapods has been explored in terms of morphological disparity, but less commonly using ecological\u2010functional categories. Here we use ecospace modelling to quantify ecological disparity across all Mesozoic marine tetrapods. We document the explosive radiation of marine tetrapod groups in the Triassic and their rapid attainment of high ecological disparity. Late Triassic extinctions led to a marked decline in ecological disparity, and the recovery of ecospace and ecological disparity was sluggish in the Early Jurassic. High levels of ecological disparity were again achieved by the Late Jurassic and maintained during the Cretaceous, when the ecospace became saturated by the Late Cretaceous. Sauropterygians, turtles and ichthyosauromorphs were the largest contributors to ecological disparity. Throughout the Mesozoic, we find that established groups remained ecologically conservative and did not explore occupied or vacant niches. Several parts of the ecospace remained vacant for long spans of time. Newly evolved, radiating taxa almost exclusively explored unoccupied ecospace, suggesting that abiotic releases are needed to empty niches and initiate diversification. In the balance of evolutionary drivers in Mesozoic marine tetrapods, abiotic factors were key to initiating diversification events, but biotic factors dominated the subsequent generation of ecological diversity.", "keyphrases": ["mesozoic", "marine tetrapod", "diversification", "sea"]}
{"id": "10.1126/sciadv.1501005", "title": "A new time tree reveals Earth history\u2019s imprint on the evolution of modern birds", "abstract": "Estimates of the timing of evolution of modern birds reveals the influence of paleogeography and paleoclimate on diversification. Determining the timing of diversification of modern birds has been difficult. We combined DNA sequences of clock-like genes for most avian families with 130 fossil birds to generate a new time tree for Neornithes and investigated their biogeographic and diversification dynamics. We found that the most recent common ancestor of modern birds inhabited South America around 95 million years ago, but it was not until the Cretaceous-Paleogene transition (66 million years ago) that Neornithes began to diversify rapidly around the world. Birds used two main dispersion routes: reaching the Old World through North America, and reaching Australia and Zealandia through Antarctica. Net diversification rates increased during periods of global cooling, suggesting that fragmentation of tropical biomes stimulated speciation. Thus, we found pervasive evidence that avian evolution has been influenced by plate tectonics and environmental change, two basic features of Earth\u2019s dynamics.", "keyphrases": ["new time tree", "modern bird", "diversification", "neornithes"]}
{"id": "paleo.010363", "title": "Population Genomic Analysis of Ancient and Modern Genomes Yields New Insights into the Genetic Ancestry of the Tyrolean Iceman and the Genetic Structure of Europe", "abstract": "Genome sequencing of the 5,300-year-old mummy of the Tyrolean Iceman, found in 1991 on a glacier near the border of Italy and Austria, has yielded new insights into his origin and relationship to modern European populations. A key finding of that study was an apparent recent common ancestry with individuals from Sardinia, based largely on the Y chromosome haplogroup and common autosomal SNP variation. Here, we compiled and analyzed genomic datasets from both modern and ancient Europeans, including genome sequence data from over 400 Sardinians and two ancient Thracians from Bulgaria, to investigate this result in greater detail and determine its implications for the genetic structure of Neolithic Europe. Using whole-genome sequencing data, we confirm that the Iceman is, indeed, most closely related to Sardinians. Furthermore, we show that this relationship extends to other individuals from cultural contexts associated with the spread of agriculture during the Neolithic transition, in contrast to individuals from a hunter-gatherer context. We hypothesize that this genetic affinity of ancient samples from different parts of Europe with Sardinians represents a common genetic component that was geographically widespread across Europe during the Neolithic, likely related to migrations and population expansions associated with the spread of agriculture.", "keyphrases": ["new insight", "genetic structure", "europe", "migration"]}
{"id": "10.1002/ajpa.10077", "title": "Serpens endocrania symmetrica (SES): a new term and a possible clue for identifying intrathoracic disease in skeletal populations.", "abstract": "This paper describes a phenomenon in the endocranial plate, which we have termed \"serpens endocrania symmetrica\" (SES), and discusses its value as a diagnostic tool. The affected discolored bone area exhibits disruption of the endocranial surface, lending it a maze-like appearance. Histological sections demonstrate that the process is limited to the most superficial portion of the endocranium, with no diploic and ectocranial involvement (sinus areas excepted). Adult skulls (n = 1,884) from the Hamann-Todd collection (HTH), housed at the Cleveland Museum of Natural History, were utilized for the present study. SES was recognized in 32 of the 1,884 skulls studied (1.7%). The frequency of SES among individuals reported to have died from tuberculosis (TB) was 4.4%. The rate of SES in the non-TB sample was only 0.53%. The locations were as follows: limited to sinus area, 28.1%; calvarium (excluding the sinuses), 46.9%; sinus + calvarium, 25.0%. SES was bilateral in 90.9% of cases. Twenty-five of the 32 individuals (78.1%) with SES in the HTH collection had tuberculosis specifically listed as the cause of death. Six of the other 7 individuals had infections other than TB. In 29 of the 32 individuals with SES, infection involved structures within the thorax. As SES was also associated with another osteological phenomenon known to represent pulmonary disease, i.e., hypertrophic osteoarthropathy (HOA; 68.0% of SES individuals also had HOA), SES may be of diagnostic value in paleopathology for the recognition of intrathoracic disease, and perhaps tuberculosis.", "keyphrases": ["ses", "intrathoracic disease", "disease", "ectocranial involvement", "serpen endocrania symmetrica"]}
{"id": "paleo.010159", "title": "Pteropods are excellent recorders of surface temperature and carbonate ion concentration", "abstract": "Pteropods are among the first responders to ocean acidification and warming, but have not yet been widely explored as carriers of marine paleoenvironmental signals. In order to characterize the stable isotopic composition of aragonitic pteropod shells and their variation in response to climate change parameters, such as seawater temperature, pteropod shells (Heliconoides inflatus) were collected along a latitudinal transect in the Atlantic Ocean (31\u00b0 N to 38\u00b0 S). Comparison of shell oxygen isotopic composition to depth changes in the calculated aragonite equilibrium oxygen isotope values implies shallow calcification depths for H. inflatus (75 m). This species is therefore a good potential proxy carrier for past variations in surface ocean properties. Furthermore, we identified pteropod shells to be excellent recorders of climate change, as carbonate ion concentration and temperature in the upper water column have dominant influences on pteropod shell carbon and oxygen isotopic composition. These results, in combination with a broad distribution and high abundance, make the pteropod species studied here, H. inflatus, a promising new proxy carrier in paleoceanography.", "keyphrases": ["excellent recorder", "carbonate ion concentration", "paleoceanography", "pteropod"]}
{"id": "10.1017/jpa.2022.21", "title": "Nonmineralized triradial conulariids from the lowermost Cambrian Stage 2 of the Olenek Uplift, Siberian Platform", "abstract": "Abstract. In the early Cambrian fossil record, triradial symmetry is typical for anabaritids and occurs among carinachitids. The former are an extinct group of minute benthic cnidarians covered with a calcareous tubular exoskeleton. The origin of the anabaritids is poorly understood, but previously reported triradial pyramid-shaped steinkerns and molds of the oldest conulariids, Vendoconularia, from the upper Ediacaran of the White Sea region suggested the anabaritids were closely related to conulariids. However, triradial symmetry could originate independently in different lineages in the late Ediacaran and early Cambrian. Herein we describe a new taxon, Ilankirus kessyusensis new genus new species, from the base of the Cambrian Stage 2 of the Olenek Uplift (Siberian Platform). These fossils occur as ornamented steinkerns in the shape of trilateral pyramids and lack any relics of a mineralized exoskeleton. Abundant plastic deformations and fractures of the casts suggest the organism was weakly if at all mineralized. The steinkerns are encrusted with a thin patina of iron-rich chlorite (chamosite) formed because of a multistage diagenetic replacement of authigenic glauconite (glauconite\u2013berthierine\u2013chamosite) under reducing conditions of oxygen-depauperate pore- and seawater. Both lacking two major autapomorphies of the crown-group conulariids (mineralized periderm and quadrate cross section of the oral region of the periderm), the late Ediacaran triradial Vendoconularia and Terreneuvian Ilankirus represent stem-group conulariids.", "keyphrases": ["conulariid", "cambrian stage", "olenek uplift"]}
{"id": "10.1098/rsta.2012.0524", "title": "The PRISM (Pliocene palaeoclimate) reconstruction: time for a paradigm shift", "abstract": "Global palaeoclimate reconstructions have been invaluable to our understanding of the causes and effects of climate change, but single-temperature representations of the oceanic mixed layer for data\u2013model comparisons are outdated, and the time for a paradigm shift in marine palaeoclimate reconstruction is overdue. The new paradigm in marine palaeoclimate reconstruction stems the loss of valuable climate information and instead presents a holistic and nuanced interpretation of multi-dimensional oceanographic processes and responses. A wealth of environmental information is hidden within the US Geological Survey's Pliocene Research, Interpretation and Synoptic Mapping (PRISM) marine palaeoclimate reconstruction, and we introduce here a plan to incorporate all valuable climate data into the next generation of PRISM products. Beyond the global approach and focus, we plan to incorporate regional climate dynamics with emphasis on processes, integrating multiple environmental proxies wherever available in order to better characterize the mixed layer, and developing a finer time slice within the Mid-Piacenzian Age of the Pliocene, complemented by underused proxies that offer snapshots into environmental conditions. The result will be a proxy-rich, temporally nested, process-oriented approach in a digital format\u2014a relational database with geographic information system capabilities comprising a three-dimensional grid representing the surface layer, with a plethora of data in each cell.", "keyphrases": ["prism", "pliocene", "paradigm shift"]}
{"id": "10.1144/gsjgs.142.2.0375", "title": "Palaeozoic, Mesozoic and contemporaneous megaspores from the Tertiary of southern England: indicators of sedimentary provenance and ancient vegetation", "abstract": "Megaspores are recorded from several localities in the Thanet and Reading Beds (upper Palaeocene) of southern England. Evidence from their taxonomic affinity, colour, compression and state of preservation indicates three separate groups: two reworked from lower Westphalian Coal Measures and Lower Cretaceous sequences, respectively, and one of contemporaneous forms. Mesozoic megaspores redeposited in the British Tertiary have not previously been recorded. Isolated Carboniferous forms have been found before but their possible value in provenance studies has not been fully explored. The new material includes a diverse assemblage of numerous Westphalian and Lower Cretaceous forms from a single horizon in the Thanet Beds. Of possible source areas it seems most likely that these spores were reworked from the Moray Firth Basin, and elsewhere near the present eastern coast of Scotland, by means of longshore drift following a roughly N\u2013S palaeocoastline. Evidence from other studies of heavy mineral assemblages and palaeogeography also indicates derivation of Thanet Beds sediments by this means. The Cenozoic megaspores include an Azolla (water fern) and two distinct lycopsid forms, one probably of selaginellalean and one of isoetalean affinity. These latter provide the first clear evidence of lycopsids in British Tertiary floras and expand our knowledge of freshwater macrophytes of that time. The assemblages of Minerisporites show morphological trends which may prove to be of biostratigraphic value.", "keyphrases": ["megaspore", "southern england", "minerisporites"]}
{"id": "10.1017/jpa.2015.43", "title": "Middle Cambrian through lowermost Ordovician conodonts from Hunan, South China", "abstract": "Abstract Since 1986, samples with a total mass of more than 14,000 kg, mainly from three key sections in western Hunan, South China, have been processed for conodonts. Previous work mainly focused on biostratigraphy, but the taxonomy has been performed only on the faunas of the middle Cambrian. Described herein are conodonts of the upper Cambrian (Furongian Series) through lowermost Ordovician from Hunan, South China. Conodonts of the middle Cambrian are redescribed, based on material that has been recovered for more than three decades. The fauna consists of 82 species belonging to 36 genera. Newly established genera are Lugnathus n. gen., Miaognathus n. gen., Millerodontus n. gen., Tujiagnathus n. gen., Wangcunella n. gen. and Wangcunognathus n. gen. New species are Coelocerodontus hunanensis n. sp., Furnishina wangcunensis n. sp., Laiwugnathus hunanensis n. sp., Laiwugnathus transitans n. sp., Lugnathus hunanensis n. gen. n. sp., Miaognathus multicostatus n. gen. n. sp., Millerodontus intermedius n. gen. n. sp., Prosagittodontus compressus n. sp., Tujiagnathus gracilis n. gen. n. sp., Wangcunella conicus n. gen. n. sp., Wangcunognathus elegans n. gen. n. sp., Westergaardodina dimorpha n. sp., Westergaardodina gigantea n. sp., and Westergaardodina sola n. sp. The taxonomy of some conodont genera is revised. In the light of histological investigation, genera are assigned to euconodonts, paraconodonts, or protoconodonts. The 13 conodont zones previously proposed in the middle Cambrian through lowermost Ordovician remain the same, but taxa within these conodont zones are documented more clearly because of the revised taxonomy proposed herein.", "keyphrases": ["conodont", "south china", "middle cambrian"]}
{"id": "paleo.003872", "title": "Cranial anatomy and taxonomy of the erythrosuchid archosauriform \u2018Vjushkovia triplicostata\u2019 Huene, 1960, from the Early Triassic of European Russia", "abstract": "Erythrosuchidae are a globally distributed and important group of apex predators that occupied Early and Middle Triassic terrestrial ecosystems following the Permo-Triassic mass extinction. The stratigraphically oldest known genus of Erythrosuchidae is Garjainia Ochev, 1958, which is known from the late Early Triassic (late Olenekian) of European Russia and South Africa. Two species of Garjainia have been reported from Russia: the type species, Garjainia prima Ochev, 1958, and \u2018Vjushkovia triplicostata\u2019 von Huene, 1960, which has been referred to Garjainia as either congeneric (Garjainia triplicostata) or conspecific (G. prima). The holotype of G. prima has received relatively extensive study, but little work has been conducted on type or referred material attributed to \u2018V. triplicostata\u2019. However, this material includes well-preserved fossils representing all parts of the skeleton and comprises seven individuals. Here, we provide a comprehensive description and review of the cranial anatomy of material attributed to \u2018V. triplicostata\u2019, and draw comparisons with G. prima. We conclude that the two Russian taxa are indeed conspecific, and that minor differences between them result from a combination of preservation or intraspecific variation. Our reassessment therefore provides additional information on the cranial anatomy of G. prima. Moreover, we quantify relative head size in erythrosuchids and other early archosauromorphs in an explicit phylogenetic context for the first time. Our results show that erythrosuchids do indeed appear to have disproportionately large skulls, but that this is also true for other early archosauriforms (i.e. proterosuchids), and may reflect the invasion of hypercarnivorous niches by these groups following the Permo-Triassic extinction.", "keyphrases": ["erythrosuchid", "vjushkovia triplicostata", "russia", "holotype", "cranial anatomy"]}
{"id": "paleo.000121", "title": "Cavity-dwelling microorganisms from the Ediacaran and Cambrian of North Greenland (Laurentia)", "abstract": "Abstract. Records of diagenetically mineralized, filamentous, cavity-dwelling microorganisms extend back to strata from the early Paleoproterozoic (2400 Ma). In North Greenland (Laurentia), they are first known from the Ediacaran (Neoproterozoic; ca. 600 Ma) Portfjeld Formation of southern Peary Land, in association with a biota similar to that of the Doushantuo Formation of China. The Portfjeld Formation cavity dwellers are compared with more widespread occurrences in Cambrian (Series 2, Stage 4, Miaolingian Series) strata from the same region in which assemblages in postmortal shelter structures within articulated acrotretoid brachiopods and other invertebrates are common. All specimens were recovered by digestion of carbonate samples in weak acids. The described fossils are preserved as mineral encrusted threads but this diagenetic phosphatization unfortunately obscures their biological identity.", "keyphrases": ["microorganism", "north greenland", "laurentia"]}
{"id": "10.1073/pnas.1418153112", "title": "Dynamic evolutionary change in post-Paleozoic echinoids and the importance of scale when interpreting changes in rates of evolution", "abstract": "Significance Biodiversification studies have often relied on constant-rate models of diversification. More recently, however, there has been an effort to identify changes in diversification rates within clades. This effort has largely focused on models of declining rates because many clades appear to have high initial rates, followed by slow-downs as ecological space fills. Here we provide an example of a 265 million-year-old marine invertebrate clade where evolutionary rates show a net increase over time instead. This is punctuated by intervals of high rates of morphological evolution, coinciding with major shifts in lifestyle and the evolution of new subclades. This study demonstrates the dynamic nature of evolutionary change within major clades. How ecological and morphological diversity accrues over geological time has been much debated by paleobiologists. Evidence from the fossil record suggests that many clades reach maximal diversity early in their evolutionary history, followed by a decline in evolutionary rates as ecological space fills or due to internal constraints. Here, we apply recently developed methods for estimating rates of morphological evolution during the post-Paleozoic history of a major invertebrate clade, the Echinoidea. Contrary to expectation, rates of evolution were lowest during the initial phase of diversification following the Permo-Triassic mass extinction and increased over time. Furthermore, although several subclades show high initial rates and net decreases in rates of evolution, consistent with \u201cearly bursts\u201d of morphological diversification, at more inclusive taxonomic levels, these bursts appear as episodic peaks. Peak rates coincided with major shifts in ecological morphology, primarily associated with innovations in feeding strategies. Despite having similar numbers of species in today\u2019s oceans, regular echinoids have accrued far less morphological diversity than irregular echinoids due to lower intrinsic rates of morphological evolution and less morphological innovation, the latter indicative of constrained or bounded evolution. These results indicate that rates of evolution are extremely heterogenous through time and their interpretation depends on the temporal and taxonomic scale of analysis.", "keyphrases": ["evolutionary change", "echinoid", "innovation"]}
{"id": "10.1111/j.1502-3931.1995.tb01423.x", "title": "The astragalus of Paleogene artiodactyls: comparative morphology, variability and prediction of body mass", "abstract": "Martinez, J.-N. & Sudre, 1. 1995 11 30 The astragalus of Paleogene artiodactyls: comparative morphology, variability and prediction of body mass. Lethaia, Vol. 28, pp. 197\u2013209. Oslo. ISSN 0024\u20131164. \n \nThe morphology of the astragalus is analysed in nineteen Paleogene artiodactyls (suborders Palaeodonta, Suina, Ancodonta and Ruminantia). This morphology is related to the functional adaptations of the appendicular skeleton, but some diagnostic characters can be seen at the family level. For the populations examined, the proportions of this bone show a low intraspecific variability, which does not allow detection of any dimorphism. An allometric relationship between the dimensions of the astragalus and the body mass has been established for extant species, allowing estimates for the fossil species. In most cases, the interval between the two extreme estimations using the astragalus includes the estimated body mass using M/1 area. The limits of this method are discussed, and it is suggested that the dimensions of the astragalus give a better estimation of the body mass than the dental area. \u25a1Artiodactyls, astragalus, comparative morphology, body mass, allometry, Paleogene.", "keyphrases": ["astragalus", "artiodactyls", "morphology", "body mass"]}
{"id": "10.1146/annurev.ecolsys.28.1.495", "title": "Extinction Vulnerability and Selectivity: Combining Ecological and Paleontological Views", "abstract": "\u25aa Abstract\u2002Extinction is rarely random across ecological and geological time scales. Traits that make some species more extinction-prone include individual traits, such as body size, and abundance. Substantial consistency appears across ecological and geological time scales in such traits. Evolutionary branching produces phylogenetic (as often measured by taxonomic) nesting of extinction-biasing traits at many scales. An example is the tendency, seen in both fossil and modern data, for higher taxa living in marine habitats to have generally lower species extinction rates. At lower taxononomic levels, recent bird and mammal extinctions are concentrated in certain genera and families. A fundamental result of such selectivity is that it can accelerate net loss of biodiversity compared to random loss of species among taxa. Replacement of vulnerable taxa by rapidly spreading taxa that thrive in human-altered environments will ultimately produce a spatially more homogenized biosphere with much lower net diversity.", "keyphrases": ["selectivity", "extinction vulnerability", "high taxa"]}
{"id": "paleo.011442", "title": "A one-billion-year-old multicellular chlorophyte", "abstract": "Chlorophytes (which represent a clade within the Viridiplantae and a sister group of the Streptophyta) probably dominated marine export bioproductivity and played a key role in facilitating ecosystem complexity before the Mesozoic diversification of phototrophic eukaryotes such as diatoms, coccolithophorans, and dinoflagellates. Molecular clock and biomarker data indicate that chlorophytes diverged in the Mesoproterozoic or early Neoproterozoic, followed by their subsequent phylogenetic diversification, multicellular evolution, and ecological expansion in the late Neoproterozoic and Paleozoic. This model, however, has not been rigorously tested with paleontological data because of the scarcity of Proterozoic chlorophyte fossils. Here we report abundant millimeter-sized, multicellular, and morphologically differentiated macrofossils from ~1,000 Ma rocks. These fossils are described as Proterocladus antiquus new species and are interpreted as benthic siphonocladalean chlorophytes, suggesting that chlorophytes acquired macroscopic size, multicellularity, and cellular differentiation nearly a billion years ago, much earlier than previously thought.", "keyphrases": ["chlorophyte", "diversification", "proterocladus antiquus"]}
{"id": "paleo.000714", "title": "Paleoneurology of Teyumbaita sulcognathus (Diapsida: Archosauromorpha) and the sense of smell in rhynchosaurs", "abstract": "Rhynchosaurs were a group of archosauromorphs that dominated the guild of herbivores during the early Late Triassic. Despite the large number of specimens available, paleobiological studies are rare in the literature, especially concerning the South American species. The present study analyzes the paleoneurology of Teyumbaita sulcognathus, a Brazilian hyperodapedontine rhynchosaur, along with its nasal cavity, based on tomographic images of the specimen UFRGS-PV-0232-T. Although the endocast only reveals the morphology of the posterior half of the encephalon due to the incompletely ossified braincase, it is possible to infer the presence of great olfactory bulbs because of their impressions left on the ventral surface of the frontals. Although the snout is relatively short, the areas of the nasal cavity probably devoted to olfaction were also large and, along with the size of the olfactory bulbs, it is possible to infer that olfaction was important for the behavior and ecology of T. sulcognathus, as previously proposed for Hyperodapedon.", "keyphrases": ["teyumbaita sulcognathus", "rhynchosaur", "late triassic", "paleoneurology"]}
{"id": "10.1080/03115518.2016.1196437", "title": "Howchinia Cushman, 1927 (Foraminifera) from the Mississippian Bei\u2019an Formation and its distribution in South China", "abstract": "Shen, Y. & Wang, X.L., July 2016. Howchinia Cushman, 1927 (Foraminifera) from the Mississippian Bei\u2019an Formation and its distribution in South China. Alcheringa 40, xxx\u2013xxx. ISSN 0311-5518. Howchinia Cushman is a useful biostratigraphic marker for Mississippian rocks. In South China, Howchinia has been reported from four sections: the Bei\u2019an, Baping, Naqing and Yashui sections; with high species diversity in the Bei\u2019an section. Ten species from the Mississippian Bei\u2019an Formation in the Bei\u2019an section are described in this paper: Howchinia bradyana, H. beleutensis, H. gibba, H. plana, H. convexa, H. subconica, H. subplana, Howchinia sp. A, Howchinia sp. B. and Howchinia beianensis sp. nov. Howchinia ranges from late Visean to early Bashkirian in South China. Howchinia species inhabited both shallow-water and relatively deep-water environments. Yang Shen [shenybj@126.com] and Xun-Lian Wang [wxl@cugb.edu.cn], State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, 29 Xueyuan Road, Beijing 100083, PR China.", "keyphrases": ["foraminifera", "south china", "howchinia cushman"]}
{"id": "10.1029/2000PA000616", "title": "Sedimentary phosphorus record from the Oman margin: New evidence of high productivity during glacial periods", "abstract": "[1]\u00a0The northern region of the Arabian Sea is one of the biologically most fertile regions of the world oceans, with present productivity rates varying between 150 and 2500 mgC/m2 \u00d7 day [Madhupratap et al., 1996]. This is related to the influence of the southwesterly summer monsoon which causes vigorous upwelling along the Oman margin. Upwelling ceases during northeasterly winter monsoon activity; productivity rates, however, remain relatively high (about 800 mgC/m2 \u00d7 day), related to deep water mixing [Madhupratap et al., 1996]. The goal of this study is to verify if during the last glacial period, a period in which winter monsoon conditions prevailed, productivity rates were similarly high. With an analysis of phosphorus phases, stable nitrogen isotopes, organic matter content, and bulk mineralogy of the upper 10 m of the cores of ODP Hole 724C (corresponding to the last 140,000 years, sample resolution is \u223c5 kyr), we provide new evidence of high productivity during this last glacial period (marine isotopic stages 2, 3, and 4). This was probably related to the combined effect of (1) increased eolian input of iron-containing dust due to dryness on the adjacent continent and stronger winter monsoon, and (2) regeneration and diffusion of dissolved phosphorus from the sediments to the water column due to variations in the position and intensity of the Oxygen Minimum Zone. These findings suggest that there is no one-to-one relationship between summer monsoon activity and productivity, which emerges to be a quasi-persistent phenomenon across glacial and interglacial stages.", "keyphrases": ["new evidence", "glacial period", "winter monsoon"]}
{"id": "10.3389/fevo.2020.00183", "title": "Ignoring Fossil Age Uncertainty Leads to Inaccurate Topology and Divergence Time Estimates in Time Calibrated Tree Inference", "abstract": "Time calibrated trees are challenging to estimate for many extinct groups of species due to the incompleteness of the rock and fossil records. Additionally, the precise age of a sample is typically not known as it may have occurred at any time during the time interval spanned by the rock layer. Bayesian phylogenetic approaches provide a coherent framework for incorporating multiple sources of evidence and uncertainty. In this study, we simulate datasets with characteristics typical of Palaeozoic marine invertebrates, in terms of character and taxon sampling. We use these datasets to examine the impact of different age handling methods on estimated topologies and divergence times obtained using the fossilized birth-death process. Our results reiterate the importance of modeling fossil age uncertainty, although we find that the relative impact of fossil age uncertainty depends on both fossil taxon sampling and character sampling. Sampling the fossil ages as part of the inference gives topology and divergence time estimates that are as good as those obtained by fixing ages to the truth, whereas fixing fossil ages to incorrect values results in higher error and lower coverage. The relative effect increases with increased fossil and character sampling. Modeling fossil age uncertainty is thus critical, as fixing incorrect fossil ages will negate the benefits of improved fossil and character sampling.", "keyphrases": ["fossil age uncertainty", "topology", "birth-death process"]}
{"id": "paleo.012523", "title": "Biological evidence supports an early and complex emergence of the Isthmus of Panama", "abstract": "Significance The formation of the Isthmus of Panama, which linked North and South America, is key to understanding the biodiversity, oceanography, atmosphere, and climate in the region. Despite its importance across multiple disciplines, the timing of formation and emergence of the Isthmus and the biological patterns it created have been controversial. Here, we analyze molecular and fossil data, including terrestrial and marine organisms, to show that biotic migrations across the Isthmus of Panama began several million years earlier than commonly assumed. An earlier evolution of the Isthmus has broad implications for the mechanisms driving global climate (e.g., Pleistocene glaciations, thermohaline circulation) as well as the rich biodiversity of the Americas. The linking of North and South America by the Isthmus of Panama had major impacts on global climate, oceanic and atmospheric currents, and biodiversity, yet the timing of this critical event remains contentious. The Isthmus is traditionally understood to have fully closed by ca. 3.5 million years ago (Ma), and this date has been used as a benchmark for oceanographic, climatic, and evolutionary research, but recent evidence suggests a more complex geological formation. Here, we analyze both molecular and fossil data to evaluate the tempo of biotic exchange across the Americas in light of geological evidence. We demonstrate significant waves of dispersal of terrestrial organisms at approximately ca. 20 and 6 Ma and corresponding events separating marine organisms in the Atlantic and Pacific oceans at ca. 23 and 7 Ma. The direction of dispersal and their rates were symmetrical until the last ca. 6 Ma, when northern migration of South American lineages increased significantly. Variability among taxa in their timing of dispersal or vicariance across the Isthmus is not explained by the ecological factors tested in these analyses, including biome type, dispersal ability, and elevation preference. Migration was therefore not generally regulated by intrinsic traits but more likely reflects the presence of emergent terrain several millions of years earlier than commonly assumed. These results indicate that the dramatic biotic turnover associated with the Great American Biotic Interchange was a long and complex process that began as early as the Oligocene\u2013Miocene transition.", "keyphrases": ["emergence", "isthmus", "panama", "south america"]}
{"id": "10.1080/02724634.1999.10011166", "title": "Enamel microstructure of Recent and fossil Canidae (Carnivora: Mammalia)", "abstract": "ABSTRACT The tooth enamel of living and fossil Canidae has been studied to test the hypothesis that a special type of Hunter-Schreger bands (HSB), termed zigzag HSB, is associated with bone consumption. It is shown that in the enamel of Canidae, as in other Carnivora, three types of HSB occur: (1) undulating, (2) acute-angled, and (3) zigzag HSB. Mapping the occurrence of these different types on to the proposed phylogeny of the Canidae indicates that zigzag HSB were derived from undulating bands. Undulating HSB, which have a three-dimensional simple structure, are associated with an insectivorous to carnivorous diet, whereas zigzag HSB occur in taxa that consume bone. Complex three-dimensional zigzag HSB increase the resistance of enamel to formation and propagation of cracks under greater loading of the teeth during bone crushing.", "keyphrases": ["fossil canidae", "carnivora", "tooth"]}
{"id": "10.1130/G40093.1", "title": "Strontium and carbon isotopic evidence for decoupling of pCO2 from continental weathering at the apex of the late Paleozoic glaciation", "abstract": "Earth\u2019s penultimate icehouse (ca. 340\u2013285 Ma) was a time of low atmospheric pCO2 and high pO2, formation of the supercontinent Pangaea, dynamic glaciation in the Southern Hemisphere, and radiation of the oldest tropical rainforests. Although it has been long appreciated that these major tectonic, climatic, and biotic events left their signature on seawater 87Sr/86Sr through their influence on Sr fluxes to the ocean, the temporal resolution and precision of the late Paleozoic seawater 87Sr/86Sr record remain relatively low. Here we present a high-temporal-resolution and high-fidelity record of Carboniferous\u2013early Permian seawater 87Sr/86Sr based on conodont bioapatite from an open-water carbonate slope succession in south China. The new data define a rate of long-term rise in 87Sr/86Sr (0.000035/m.y.) from ca. 334\u2013318 Ma comparable to that of the middle to late Cenozoic. The onset of the rapid decline in 87Sr/86Sr (0.000043/m.y.), following a prolonged plateau (318\u2013303 Ma), is constrained to ca. 303 Ma. A major decoupling of 87Sr/86Sr and pCO2 during 303\u2013297 Ma, coincident with the Paleozoic peak in pO2, widespread low-latitude aridification, and demise of the pan-tropical wetland forests, suggests a major shift in the dominant influence on pCO2 from continental weathering and organic carbon sequestration (as coals) on land to organic carbon burial in the ocean. INTRODUCTION Seawater 87Sr/86Sr has long been used as a tool for chronostratigraphic correlation (e.g., McArthur et al., 2012), and, in combination with global seawater \u03b413C, to constrain the timing and magnitude of tectonic events, continental weathering, and paleoclimate change (e.g., Kump and Arthur, 1997; Godd\u00e9ris et al., 2017). For the middle to late Cenozoic, the highresolution seawater 87Sr/86Sr curve has provided robust chronostratigraphic constraints and insight into the interlinked processes of the Earth system during our modern icehouse (e.g., Zachos et al., 1999). The late Paleozoic ice age (LPIA, ca. 340\u2013285 Ma) is one of two major icehouses of the Phanerozoic, and records the only greenhouse gas\u2013forced transition from an icehouse with complex terrestrial ecosystems to a fully greenhouse world (Monta\u00f1ez and Poulsen, 2013). The LPIA was a time of very low atmospheric pCO2 (Monta\u00f1ez et al., 2016) and high pO2 (Glasspool et al., 2015), dynamic glaciation on Gondwana (Isbell et al., 2012), global tectonic reconfiguration (Veevers, 2013), and the evolution and radiation of the oldest tropical rainforests (DiMichele, 2014). The fingerprints of these events should have been recorded in seawater 87Sr/86Sr given they collectively influenced continental weathering, and thus Sr flux to the late Paleozoic oceans. The existing Carboniferous\u2013early Permian seawater 87Sr/86Sr record derived using calcitic brachiopods (Bruckschen et al., 1999; Korte et al., 2006) remains only moderately resolved, reflecting stratigraphic uncertainties, relatively low temporal resolution, and possible diagenetic alteration. Here, we present a 87Sr/86Sr record of unprecedented temporal resolution (105 yr) for ~38 m.y. of the LPIA, built using conodont bioapatite from an open-water carbonate slope succession (Naqing, south China) of the eastern Paleo-Tethys Ocean (Fig. DR1 in the GSA Data Repository1). Our record refines the structure of the middle Mississippian to early Permian seawater 87Sr/86Sr curve and places more precise temporal constraints on the timing of major shifts and rates of change. Integrated conodont apatite 87Sr/86Sr and carbonate \u03b413C records provide insight into the relative roles of orogenic uplift, pan-tropical aridification, and the evolution of the paleo-tropical wetland rainforests on continental weathering and atmospheric pCO2 during Earth\u2019s penultimate icehouse. GEOLOGIC SETTING AND METHODS During the Carboniferous\u2013Permian, the South China Block was a nearly isolated terrain located at the interface of the Paleo-Tethys Ocean (west) and Panthalassic Ocean (east) (Fig. DR1). The Carboniferous\u2013 Permian Naqing succession in the Guizhou Province consists of thinbedded lime mudstones intercalated with intraclast-bearing bioclastic wackestones to packstones (Fig. 1), and contains abundant conodonts with complete evolutionary lineages (Qi et al., 2014). The succession records near-continuous, hemipelagic deposition on a carbonate slope episodically punctuated by turbidity currents and debris flows in the Qian-Gui Basin that defined an open-water seaway to the Paleo-Tethys Ocean (Buggisch et al., 2011; Chen et al., 2016). Sr was isolated from conodonts (n = 99) and carbonates (n = 22), collected from the Naqing section, using Eichrom exchange resin (50\u2013 100 \u03bcm) in pipette-tip columns attached to a Watson Marlow 205U Peristaltic pump (detailed methods are provided in the Data Repository). The 87Sr/86Sr ratios were measured on a Nu Plasma HR (Nu032) multicollector\u2013inductively coupled plasma\u2013mass spectrometer (MC-ICPMS) at the University of California\u2013Davis (USA). Analytical precision (2 standard deviations [SD] = \u00b10.000026) is based on repeated 87Sr/86Sr analysis of 1 GSA Data Repository item 2018128, analytical methods, age calibration, revision of pCO2 estimates, Figures DR1 and DR2, and Tables DR1 and DR2, is available online at http://www.geosociety.org/datarepository/2018/, or on request from editing@geosociety.org. *E-mail: jtchen@nigpas.ac.cn GEOLOGY, May 2018; v. 46; no. 5; p. 395\u2013398 | GSA Data Repository item 2018128 | https://doi.org/10.1130/G40093.1 | Published online 1 March 2018 \u00a9 2018 The Authors. Gold Open Access: This paper is published under the terms of the CC-BY license. Downloaded from https://pubs.geoscienceworld.org/gsa/geology/article-pdf/4134043/395.pdf by guest on 31 October 2019 396 www.gsapubs.org | Volume 46 | Number 5 | GEOLOGY strontium carbonate isotopic standard SRM 987 (avg. of 0.710251; n = 44) over the study period. All data are normalized to a SRM 987 value of 0.710249. RESULTS AND DISCUSSION Refined Seawater 87Sr/86Sr Conodont apatite 87Sr/86Sr values from the Naqing section delineate three phases during the middle Mississippian to early Permian (Fig. 1; Fig. DR2). First, after a brief decline from 0.70780 to 0.70769 during the Middle Mississippian (ca. 336\u2013334 Ma), 87Sr/86Sr values increase rapidly (avg. of 0.000035/m.y.) over a 16 m.y. period (334\u2013318 Ma) to 0.70827. Second, the 87Sr/86Sr values define an ~15 m.y. plateau throughout much of the Pennsylvanian (318\u2013303 Ma). Third, 87Sr/86Sr values decline, at an average rate of 0.000043/m.y., from ca. 303 Ma through to the end of the record in the early Permian (ca. 298 Ma). The 87Sr/86Sr values of diagenetically screened micrite from the Naqing section are overall higher, by up to 0.00029, than co-existing conodonts and exhibit greater scatter (Fig. 1). The Naqing conodont 87Sr/86Sr record largely agrees with a published first-order 87Sr/86Sr trend (Bruckschen et al., 1999; Korte et al., 2006), but with significantly less scatter and greater continuity (Fig. 2B). The Naqing data, with minimal stratigraphic uncertainty and higher temporal resolution (105 yr), refine the trend and fill in existing gaps. Notably, the Naqing 87Sr/86Sr values are comparable, within analytical uncertainty, with those of brachiopods from Panthalassic open-ocean settings (Brand et al., 2009) and of conodonts from the highprecision U-Pb calibrated Russian succession (Henderson et al., 2012). Seawater 87Sr/86Sr represents a mixture of two main sources: a continent-derived, more-radiogenic weathering flux, and mantle-derived, lessradiogenic volcanic and hydrothermal fluxes. The rise in 87Sr/86Sr during ca. 334\u2013318 Ma likely records the increased 87Sr/86Sr ratio of the riverine flux due to exposure and weathering of uplifted radiogenic basement rocks (Godd\u00e9ris et al., 2017) driven by the Hercynian orogeny (ca. 340\u2013260 Ma; Hatcher, 2002; Veevers, 2013). The subsequent protracted (15 m.y.) 87Sr/86Sr plateau (318\u2013303 Ma) is interpreted to record sustained high87Sr/86Sr riverine flux due to westward progression of maximum elevations and subsequent rapid denudation of the highlands in the paleo-tropics. The new 87Sr/86Sr record indicates a rate of rise comparable to that of last 34 m.y. of the Cenozoic icehouse (0.000040/m.y.; McArthur et al., 2012, and references therein), suggesting that increased global weatherability due to orogenic uplift may be a common driver of these icehouses (cf. Kump and Arthur, 1997). Conversely, the rapid, near-linear decline in 87Sr/86Sr ca. 303\u2013285 Ma likely records decreased continental (silicate) weathering. This raises a paradox, as the potential for tectonically driven weatherability most likely remained unchanged through the early Permian (cf. Godd\u00e9ris et al., 2017) with continued orogenesis to ca. 260 Ma (Hatcher, 2002). We hypothesize that continental weathering likely decreased during this time based on two other factors. First, the onset of widespread aridification in pan-tropical regions that began in the late Moscovian and intensified with time eastward across Pangaea through to the early Permian (Tabor and Poulsen, 2008; Michel et al., 2015) would have dramatically decreased silicate weathering. Second, the Euramerican tropical wetland forests underwent permanent turnover toward the close of the Carboniferous to dryland forests with less weathering potential (Wilson et al., 2017). Moreover, weathering of less-radiogenic basaltic provinces, which were emplaced initially in the latest Carboniferous and throughout the early Permian opening of the Neo-Tethys (e.g., Liao et al., 2015), may have contributed to declining 87Sr/86Sr. The relative contribution of basalt weathering on global seawater 87Sr/86Sr, however, was likely small in the latest Carboniferous\u2013earliest Permian, as early basaltic province emplacement was limited in volume and occurred primarily in mid-latitude regions (Liao et al., 2015) where weathering rates would have been lower, in particular during", "keyphrases": ["pco2", "continental weathering", "seawater"]}
{"id": "paleo.010837", "title": "Bringing Dicynodonts Back to Life: Paleobiology and Anatomy of a New Emydopoid Genus from the Upper Permian of Mozambique", "abstract": "Dicynodontia represent the most diverse tetrapod group during the Late Permian. They survived the Permo-Triassic extinction and are central to understanding Permo-Triassic terrestrial ecosystems. Although extensively studied, several aspects of dicynodont paleobiology such as, neuroanatomy, inner ear morphology and internal cranial anatomy remain obscure. Here we describe a new dicynodont (Therapsida, Anomodontia) from northern Mozambique: Niassodon mfumukasi gen. et sp. nov. The holotype ML1620 was collected from the Late Permian K5 formation, Metangula Graben, Niassa Province northern Mozambique, an almost completely unexplored basin and country for vertebrate paleontology. Synchrotron radiation based micro-computed tomography (SR\u00b5CT), combined with a phylogenetic analysis, demonstrates a set of characters shared with Emydopoidea. All individual bones were digitally segmented allowing a 3D visualization of each element. In addition, we reconstructed the osseous labyrinth, endocast, cranial nerves and vasculature. The brain is narrow and the cerebellum is broader than the forebrain, resembling the conservative, \u201creptilian-grade\u201d morphology of other non-mammalian therapsids, but the enlarged paraflocculi occupy the same relative volume as in birds. The orientation of the horizontal semicircular canals indicates a slightly more dorsally tilted head posture than previously assumed in other dicynodonts. In addition, synchrotron data shows a secondary center of ossification in the femur. Thus ML1620 represents, to our knowledge, the oldest fossil evidence of a secondary center of ossification, pushing back the evolutionary origins of this feature. The fact that the specimen represents a new species indicates that the Late Permian tetrapod fauna of east Africa is still incompletely known.", "keyphrases": ["dicynodont", "anatomy", "mozambique"]}
{"id": "paleo.000725", "title": "Evaluating the influences of temperature, primary production, and evolutionary history on bivalve growth rates", "abstract": "Organismal metabolic rates reflect the interaction of environmental and physiological factors. Thus, calcifying organisms that record growth history can provide insight into both the ancient environments in which they lived and their own physiology and life history. However, interpreting them requires understanding which environmental factors have the greatest influence on growth rate and the extent to which evolutionary history constrains growth rates across lineages. We integrated satellite measurements of sea-surface temperature and chlorophyll-a concentration with a database of growth coefficients, body sizes, and life spans for 692 populations of living marine bivalves in 195 species, set within the context of a new maximum-likelihood phylogeny of bivalves. We find that environmental predictors overall explain only a small proportion of variation in growth coefficient across all species; temperature is a better predictor of growth coefficient than food supply, and growth coefficient is somewhat more variable at higher summer temperatures. Growth coefficients exhibit moderate phylogenetic signal, and taxonomic membership is a stronger predictor of growth coefficient than any environmental predictor, but phylogenetic inertia cannot fully explain the disjunction between our findings and the extensive body of work demonstrating strong environmental control on growth rates within taxa. Accounting for evolutionary history is critical when considering shells as historical archives. The weak relationship between variation in food supply and variation in growth coefficient in our data set is inconsistent with the hypothesis that the increase in mean body size through the Phanerozoic was driven by increasing productivity enabling faster growth rates.", "keyphrases": ["influence", "evolutionary history", "growth rate", "metabolic rate"]}
{"id": "10.1017/pab.2015.30", "title": "Inferring skeletal production from time-averaged assemblages: skeletal loss pulls the timing of production pulses towards the modern period", "abstract": "Abstract. Age-frequency distributions of dead skeletal material on the landscape or seabed\u2014information on the time that has elapsed since the death of individuals\u2014provide decadal- to millennial-scale perspectives both on the history of production and on the processes that lead to skeletal disintegration and burial. So far, however, models quantifying the dynamics of skeletal loss have assumed that skeletal production is constant during time-averaged accumulation. Here, to improve inferences in conservation paleobiology and historical ecology, we evaluate the joint effects of temporally variable production and skeletal loss on postmortem age-frequency distributions (AFDs) to determine how to detect fluctuations in production over the recent past from AFDs. We show that, relative to the true timing of past production pulses, the modes of AFDs will be shifted to younger age cohorts, causing the true age of past pulses to be underestimated. This shift in the apparent timing of a past pulse in production will be stronger where loss rates are high and/or the rate of decline in production is slow; also, a single pulse coupled with a declining loss rate can, under some circumstances, generate a bimodal distribution. We apply these models to death assemblages of the bivalve Nuculana taphria from the Southern California continental shelf, finding that: (1) an onshore-offshore gradient in time averaging is dominated by a gradient in the timing of production, reflecting the tracking of shallow-water habitats under a sea-level rise, rather than by a gradient in disintegration and sequestration rates, which remain constant with water depth; and (2) loss-corrected model-based estimates of the timing of past production are in good agreement with likely past changes in local production based on an independent sea-level curve.", "keyphrases": ["skeletal production", "production", "death assemblage"]}
{"id": "paleo.007049", "title": "Systematic taxonomy of the Trilobatus sacculifer plexus and descendant Globigerinoidesella fistulosa (planktonic foraminifera)", "abstract": "The extant morphospecies of the Trilobatus sacculifer plexus (T. sacculifer, T. quadrilobatus, T. immaturus and T. trilobus) have widespread biogeographical distributions and long stratigraphical ranges, and are thus routinely utilized in palaeoceanographical studies. The descendant morphospecies Globigerinoidesella fistulosa is comparatively short-ranging (Pliocene\u2013Pleistocene) and an important biostratigraphical marker. However, taxonomic concepts of these morphospecies are inconsistently applied between workers, leading to loss of information and incomparable datasets. We present a taxonomic appraisal of each morphospecies, including detailed taxonomic histories and refinement of their morphological concepts, using a combined population-based and typological approach. Morphometric data and scanning electron microscopy are used to illustrate morphological intergradation in the Trilobatus sacculifer plexus. The distinctive morphology of Globigerinoidesella fistulosa is shown to develop from T. sacculifer (as previously documented), but also from the other morphospecies in the plexus, providing the first fossil evidence demonstrating that the four morphospecies of the T. sacculifer plexus are the same species. Our new analyses support culturing and molecular genetic evidence from extant specimens that suggests the four T. sacculifer plexus morphospecies are the same biological species. However, we advocate using the four morphospecies concepts (T. sacculifer, T. quadrilobatus, T. immaturus and T. trilobus) and G. fistulosa, here refined, to increase their palaeoecological and biostratigraphical value.", "keyphrases": ["trilobatus sacculifer plexus", "globigerinoidesella fistulosa", "morphospecie"]}
{"id": "10.1080/02724634.1983.10011959", "title": "Extreme carpal variability in Teleoceras (Rhinocerotidae, Mammalia)", "abstract": "ABSTRACT A large population of the common American Miocene rhinoceros, Teleoceras, shows extreme variability in the shape of the magnum and unciform. A small number of the specimens show a de novo posterior (volar) articulation between these two carpals. The new articulation may have been formed as an early stage in the fusion of the two bones. It is suggested that in order to evolve a complex new structure, a population will sometimes produce more variation in the affected elements than is actually necessary to form the structure.", "keyphrases": ["variability", "teleoceras", "articulation"]}
{"id": "paleo.012153", "title": "Quantifying ecological impacts of mass extinctions with network analysis of fossil communities", "abstract": "Significance The geologic record provides evidence of repeated diversification events and mass extinctions, which entailed benchmark changes in biodiversity and ecology. For insights into these events, we explore the fossil record of marine animal communities using a network-based approach to quantifying ecological change over time. The major radiations and mass extinctions of the Phanerozoic Eon resulted in the biggest ecological changes, as they involved the rise and decline of interrelated communities in relative dominance. Our analyses provide support for an ecological severity ranking of mass extinctions and illuminate the long-term consequences of the Ordovician radiation and Devonian mass depletion of biodiversity. Our work highlights the potential for irreversible ecosystem changes with species losses, both previously documented and predicted in the future. Mass extinctions documented by the fossil record provide critical benchmarks for assessing changes through time in biodiversity and ecology. Efforts to compare biotic crises of the past and present, however, encounter difficulty because taxonomic and ecological changes are decoupled, and although various metrics exist for describing taxonomic turnover, no methods have yet been proposed to quantify the ecological impacts of extinction events. To address this issue, we apply a network-based approach to exploring the evolution of marine animal communities over the Phanerozoic Eon. Network analysis of fossil co-occurrence data enables us to identify nonrandom associations of interrelated paleocommunities. These associations, or evolutionary paleocommunities, dominated total diversity during successive intervals of relative community stasis. Community turnover occurred largely during mass extinctions and radiations, when ecological reorganization resulted in the decline of one association and the rise of another. Altogether, we identify five evolutionary paleocommunities at the generic and familial levels in addition to three ordinal associations that correspond to Sepkoski\u2019s Cambrian, Paleozoic, and Modern evolutionary faunas. In this context, we quantify magnitudes of ecological change by measuring shifts in the representation of evolutionary paleocommunities over geologic time. Our work shows that the Great Ordovician Biodiversification Event had the largest effect on ecology, followed in descending order by the Permian\u2013Triassic, Cretaceous\u2013Paleogene, Devonian, and Triassic\u2013Jurassic mass extinctions. Despite its taxonomic severity, the Ordovician extinction did not strongly affect co-occurrences of taxa, affirming its limited ecological impact. Network paleoecology offers promising approaches to exploring ecological consequences of extinctions and radiations.", "keyphrases": ["ecological impact", "mass extinction", "network analysis", "evolutionary faunas", "taxonomic severity"]}
{"id": "paleo.003801", "title": "Development of cyclic shedding teeth from semi-shedding teeth: the inner dental arcade of the stem osteichthyan Lophosteus", "abstract": "The numerous cushion-shaped tooth-bearing plates attributed to the stem group osteichthyan Lophosteus superbus, which are argued here to represent an early form of the osteichthyan inner dental arcade, display a previously unknown and presumably primitive mode of tooth shedding by basal hard tissue resorption. They carry regularly spaced, recumbent, gently recurved teeth arranged in transverse tooth files that diverge towards the lingual margin of the cushion. Three-dimensional reconstruction from propagation phase-contrast synchrotron microtomography (PPC-SR\u00b5CT) reveals remnants of the first-generation teeth embedded in the basal plate, a feature never previously observed in any taxon. These teeth were shed by semi-basal resorption with the periphery of their bases retained as dentine rings. The rings are highly overlapped, which evidences tooth shedding prior to adding the next first-generation tooth at the growing edge of the plate. The first generation of teeth is thus diachronous. Successor teeth at the same sites underwent cyclical replacing and shedding through basal resorption, producing stacks of buried resorption surfaces separated by bone of attachment. The number and spatial arrangement of resorption surfaces elucidates that basal resorption of replacement teeth had taken place at the older tooth sites before the addition of the youngest first-generation teeth at the lingual margin. Thus, the replacement tooth buds cannot have been generated by a single permanent dental lamina at the lingual edge of the tooth cushion, but must have arisen either from successional dental laminae associated with the individual predecessor teeth, or directly from the dental epithelium of these teeth. The virtual histological dissection of these Late Silurian microfossils broadens our understanding of the development of the gnathostome dental systems and the acquisition of the osteichthyan-type of tooth replacement.", "keyphrases": ["inner dental arcade", "tooth", "basal resorption"]}
{"id": "paleo.011525", "title": "Recognising moulting behaviour in trilobites by examining morphology, development and preservation: Comment on B\u0142a\u017cejowski et al. 2015", "abstract": "A 365 million year\u2010old trilobite moult\u2010carcass assemblage was described by B\u0142a\u017cejowski et al. (2015) as the oldest direct evidence of moulting in the arthropod fossil record. Unfortunately, their suppositions are insufficiently supported by the data provided. Instead, the morphology, configuration and preservational context of the highly fossiliferous locality (Kowala Quarry, Poland) suggest that the specimen consists of two overlapping, queued carcasses. The wider fossil record of moulting actually extends back 520 million years, providing an unparalleled opportunity to study behaviour, ecology and development in early animals. Taking cues from modern analogues, it is possible to quantify precise details about moulting behaviour to determine broad\u2010scale evolutionary trends, ontogenetic sequences and morphological selection pressures. In this review, we argue that this rich source of data has been underused in evolutionary studies, though has great potential for investigating the life history and evolution of arthropods in deep time.", "keyphrases": ["behaviour", "trilobite", "arthropod"]}
{"id": "10.1073/pnas.1010906107", "title": "Dental evidence for ontogenetic differences between modern humans and Neanderthals", "abstract": "Humans have an unusual life history, with an early weaning age, long childhood, late first reproduction, short interbirth intervals, and long lifespan. In contrast, great apes wean later, reproduce earlier, and have longer intervals between births. Despite 80 y of speculation, the origins of these developmental patterns in Homo sapiens remain unknown. Because they record daily growth during formation, teeth provide important insights, revealing that australopithecines and early Homo had more rapid ontogenies than recent humans. Dental development in later Homo species has been intensely debated, most notably the issue of whether Neanderthals and H. sapiens differ. Here we apply synchrotron virtual histology to a geographically and temporally diverse sample of Middle Paleolithic juveniles, including Neanderthals, to assess tooth formation and calculate age at death from dental microstructure. We find that most Neanderthal tooth crowns grew more rapidly than modern human teeth, resulting in significantly faster dental maturation. In contrast, Middle Paleolithic H. sapiens juveniles show greater similarity to recent humans. These findings are consistent with recent cranial and molecular evidence for subtle developmental differences between Neanderthals and H. sapiens. When compared with earlier hominin taxa, both Neanderthals and H. sapiens have extended the duration of dental development. This period of dental immaturity is particularly prolonged in modern humans.", "keyphrases": ["ontogenetic difference", "modern human", "neanderthals", "dental development", "tooth"]}
{"id": "paleo.011674", "title": "Re-examination of the cranial osteology of the Arctic Alaskan hadrosaurine with implications for its taxonomic status", "abstract": "Hadrosaurid fossils from the Liscomb Bonebed (Prince Creek Formation, North Slope, Alaska) were the first dinosaur bones discovered from the Arctic. While the Prince Creek Formation hadrosaurids were long identified as Edmontosaurus, a member of the sub-clade Hadrosaurinae, they were recently assigned to a newly-erected taxon, Ugrunaaluk kuukpikensis. However, taxonomic status of the new taxon is ambiguous largely due to the immature nature of the specimens upon which it was based. Here we reexamine cranial elements of the Prince Creek Formation hadrosaurine in order to solve its taxonomic uncertainties. The Prince Creek Formation hadrosaurine possesses a short dorsolateral process of the laterosphenoid, one of the diagnostic characters of Edmontosaurus. The Prince Creek Formation hadrosaurine also shows affinity to Edmontosaurus regalis in the presence of a horizontal shelf of the jugal. Our morphological comparisons with other North American Edmontosaurus specimens and our phylogenetic analyses demonstrate that the Prince Creek Formation hadrosaurine should be re-assigned to Edmontosaurus. Because the Prince Creek Formation Edmontosaurus shows differences with lower latitude Edmontosaurus in a dorsoventrally short maxilla, presence of a secondary ridge on the dentary teeth, and the absence of the transverse ridge between basipterygoid processes of the basisphenoid, we consider that the Prince Creek Formation Edmontosaurus should be regarded as Edmontosaurus sp. until further discoveries of mature hadrosaurines from the Prince Creek Formation Bonebed and/or equivalently juvenile Edmontosaurus specimens from the lower latitudes allow direct comparisons. The retention of the Prince Creek Formation hadrosaurine as Edmontosaurus re-establishes a significant latitudinal distribution for this taxon. Despite the large latitudinal distribution of the taxon, the morphological disparity of Edmontosaurus is small within Hadrosaurinae. The small morphological disparity may be related to the relatively low latitudinal temperature gradient during the latest Cretaceous compared to present day, a gradient which might not have imposed significant pressure for much morphological adaptations across a broad latitudinal range.", "keyphrases": ["arctic", "hadrosaurine", "taxonomic status"]}
{"id": "10.7717/peerj.9925", "title": "Effects of taphonomic deformation on geometric morphometric analysis of fossils: a study using the dicynodont Diictodon feliceps (Therapsida, Anomodontia)", "abstract": "Taphonomic deformation, the distortion of fossils as a result of geological processes, poses problems for the use of geometric morphometrics in addressing paleobiological questions. Signal from biological variation, such as ontogenetic trends and sexual dimorphism, may be lost if variation from deformation is too high. Here, we investigate the effects of taphonomic deformation on geometric morphometric analyses of the abundant, well known Permian therapsid Diictodon feliceps. Distorted Diictodon crania can be categorized into seven typical styles of deformation: lateral compression, dorsoventral compression, anteroposterior compression, \u201csaddle-shape\u201d deformation (localized collapse at cranial mid-length), anterodorsal shear, anteroventral shear, and right/left shear. In simulated morphometric datasets incorporating known \u201cbiological\u201d signals and subjected to uniform shear, deformation was typically the main source of variance but accurate \u201cbiological\u201d information could be recovered in most cases. However, in empirical datasets, not only was deformation the dominant source of variance, but little structure associated with allometry and sexual dimorphism was apparent, suggesting that the more varied deformation styles suffered by actual fossils overprint biological variation. In a principal component analysis of all anomodont therapsids, deformed Diictodon specimens exhibit significant dispersion around the \u201ctrue\u201d position of this taxon in morphospace based on undistorted specimens. The overall variance associated with deformation for Anomodontia as a whole is minor, and the major axes of variation in the study sample show a strong phylogenetic signal instead. Although extremely problematic for studying variation in fossil taxa at lower taxonomic levels, the cumulative effects of deformation in this study are shown to be random, and inclusion of deformed specimens in higher-level analyses of morphological disparity are warranted. Mean morphologies of distorted specimens are found to approximate the morphology of undistorted specimens, so we recommend use of species-level means in higher-level analyses when possible.", "keyphrases": ["taphonomic deformation", "anomodontia", "variance", "low taxonomic level"]}
{"id": "paleo.002870", "title": "Taxonomic reassessment of Clevosaurus latidens Fraser, 1993 (Lepidosauria, Rhynchocephalia) and rhynchocephalian Phylogeny based on Parsimony and Bayesian inference", "abstract": "Abstract. \n The Late Triassic rhynchocephalian Clevosaurus latidens Fraser, 1993 is known from the fissure deposits of Cromhall Quarry, England. Many studies have questioned its referral to the genus Clevosaurus Swinton, 1939 and some phylogenetic analyses suggest a close relationship with herbivorous rhynchocephalians. We re-examine the type specimens and referred material of C. latidens to elucidate its taxonomic identity. Additionally, we provide new phylogenetic analyses of the Rhynchocephalia using both parsimony and Bayesian approaches. Our taxonomic review and both phylogenetic analyses reveal that C. latidens is not referable to Clevosaurus, but represents a new genus. We reassess C. latidens and provide an amended diagnosis for Fraserosphenodon new genus. Both parsimony and Bayesian analyses recover similar topologies and we propose formal names for two higher clades within Rhynchocephalia: Eusphenodontia new infraorder and Neosphenodontia new clade.", "keyphrases": ["clevosaurus", "rhynchocephalia", "parsimony"]}
{"id": "paleo.005609", "title": "Ecological niche modelling does not support climatically-driven dinosaur diversity decline before the Cretaceous/Paleogene mass extinction", "abstract": "In the lead-up to the Cretaceous/Paleogene mass extinction, dinosaur diversity is argued to have been either in long-term decline, or thriving until their sudden demise. The latest Cretaceous (Campanian\u2013Maastrichtian [83\u201366 Ma]) of North America provides the best record to address this debate, but even here diversity reconstructions are biased by uneven sampling. Here we combine fossil occurrences with climatic and environmental modelling to quantify latest Cretaceous North American dinosaur habitat. Ecological niche modelling shows a Campanian-to-Maastrichtian habitability decrease in areas with present-day rock-outcrop. However, a continent-wide projection demonstrates habitat stability, or even a Campanian-to-Maastrichtian increase, that is not preserved. This reduction of the spatial sampling window resulted from formation of the proto-Rocky Mountains and sea-level regression. We suggest that Maastrichtian North American dinosaur diversity is therefore likely to be underestimated, with the apparent decline a product of sampling bias, and not due to a climatically-driven decrease in habitability as previously hypothesised.", "keyphrases": ["dinosaur diversity", "paleogene mass extinction", "sampling", "ecological niche modelling", "possibility"]}
{"id": "paleo.011380", "title": "Single-stranded DNA library preparation from highly degraded DNA using T4 DNA ligase", "abstract": "Abstract DNA library preparation for high-throughput sequencing of genomic DNA usually involves ligation of adapters to double-stranded DNA fragments. However, for highly degraded DNA, especially ancient DNA, library preparation has been found to be more efficient if each of the two DNA strands are converted into library molecules separately. We present a new method for single-stranded library preparation, ssDNA2.0, which is based on single-stranded DNA ligation with T4 DNA ligase utilizing a splinter oligonucleotide with a stretch of random bases hybridized to a 3\u0384 biotinylated donor oligonucleotide. A thorough evaluation of this ligation scheme shows that single-stranded DNA can be ligated to adapter oligonucleotides in higher concentration than with CircLigase (an RNA ligase that was previously chosen for end-to-end ligation in single-stranded library preparation) and that biases in ligation can be minimized when choosing splinters with 7 or 8 random nucleotides. We show that ssDNA2.0 tolerates higher quantities of input DNA than CircLigase-based library preparation, is less costly and better compatible with automation. We also provide an in-depth comparison of library preparation methods on degraded DNA from various sources. Most strikingly, we find that single-stranded library preparation increases library yields from tissues stored in formalin for many years by several orders of magnitude.", "keyphrases": ["dna", "library preparation", "single-stranded dna"]}
{"id": "10.1098/rspb.2010.1035", "title": "Estimating the age of fire in the Cape flora of South Africa from an orchid phylogeny", "abstract": "Fire may have been a crucial component in the evolution of the Cape flora of South Africa, a region characterized by outstanding levels of species richness and endemism. However, there is, to date, no critical assessment of the age of the modern fire regime in this biome. Here, we exploit the presence of two obligate post-fire flowering clades in the orchid genus Disa, in conjunction with a robust, well-sampled and dated molecular phylogeny, to estimate the age by which fire must have been present. Our results indicate that summer drought (winter rainfall), the fire regime and the fynbos vegetation are several million years older than currently suggested. Summer drought and the fynbos vegetation are estimated to date back to at least the Early Miocene (ca 19.5 Ma). The current fire regime may have been established during a period of global cooling that followed the mid-Miocene Climatic Optimum (ca 15 Ma), which led to the expansion of open habitats and increased aridification. The first appearance of Disa species in the grassland biome, as well as in the subalpine habitat, is in striking agreement with reliable geological and palaeontological evidence of the age of these ecosystems, thus corroborating the efficacy of our methods. These results change our understanding of the historical mechanisms underlying botanical evolution in southern Africa, and confirm the potential of using molecular phylogenies to date events for which other information is lacking or inconclusive.", "keyphrases": ["fire", "cape flora", "south africa"]}
{"id": "paleo.007987", "title": "Diversity of gobioid fishes in the late middle Miocene of northern Moldova, Eastern Paratethys \u2013 part I: an extinct clade of Lesueurigobius look-alikes", "abstract": "Studies of otoliths suggest that Gobioidei, which are among the most species-rich groups of modern-day vertebrates, were prominent elements of late middle Miocene (early Sarmatian sensu lato) fish faunas in Europe and Western Asia. However, few complete skeletons have come to light. Here, we report an assemblage of six marine gobiid species, based on skeletons preserved with otoliths in situ, from the lower Volhynian (lower Sarmatian s.l.) of Karpov Yar, Naslavcea, northern Moldova (Eastern Paratethys). Previously only one of these species had been reported from the Central Paratethys, based on its otoliths alone. Five new species representing four new genera are described: \u2020Katyagobius prikryli gen. et sp. nov., Pseudolesueurigobius manfredi gen. et sp. nov., \u2020Sarmatigobius compactus gen. et sp. nov., \u2020Yarigobius decoratus gen. et sp. nov., and \u2020Y. naslavcensis gen. et sp. nov. All six species share the following set of characters, suggesting that they represent a monophyletic clade: 27-29 vertebrae (of which 10 are abdominal); spines of first dorsal fin distally filamentous; second dorsal fin with spine and 14-16 soft rays; anal fin with spine and 13-15 soft rays; caudal fin longish-to-lanceolate; otoliths (sagittae) with rounded, trapezoid-to-squarish shape. Their skeletal features suggest that they are closely related to Lesueurigobius Whitley, 1950, but the otoliths preserved in situ do not support such a classification. The new fossils most likely represent a stem lineage of the European Aphia lineage, and indicate that the diversity of gobiid lineages 12 million years ago differed clearly from that observed today.", "keyphrases": ["middle miocene", "northern moldova", "eastern paratethys"]}
{"id": "paleo.011712", "title": "A new family of diprotodontian marsupials from the latest Oligocene of Australia and the evolution of wombats, koalas, and their relatives (Vombatiformes)", "abstract": "We describe the partial cranium and skeleton of a new diprotodontian marsupial from the late Oligocene (~26\u201325 Ma) Namba Formation of South Australia. This is one of the oldest Australian marsupial fossils known from an associated skeleton and it reveals previously unsuspected morphological diversity within Vombatiformes, the clade that includes wombats (Vombatidae), koalas (Phascolarctidae) and several extinct families. Several aspects of the skull and teeth of the new taxon, which we refer to a new family, are intermediate between members of the fossil family Wynyardiidae and wombats. Its postcranial skeleton exhibits features associated with scratch-digging, but it is unlikely to have been a true burrower. Body mass estimates based on postcranial dimensions range between 143 and 171 kg, suggesting that it was ~5 times larger than living wombats. Phylogenetic analysis based on 79 craniodental and 20 postcranial characters places the new taxon as sister to vombatids, with which it forms the superfamily Vombatoidea as defined here. It suggests that the highly derived vombatids evolved from wynyardiid-like ancestors, and that scratch-digging adaptations evolved in vombatoids prior to the appearance of the ever-growing (hypselodont) molars that are a characteristic feature of all post-Miocene vombatids. Ancestral state reconstructions on our preferred phylogeny suggest that bunolophodont molars are plesiomorphic for vombatiforms, with full lophodonty (characteristic of diprotodontoids) evolving from a selenodont morphology that was retained by phascolarctids and ilariids, and wynyardiids and vombatoids retaining an intermediate selenolophodont condition. There appear to have been at least six independent acquisitions of very large (>100 kg) body size within Vombatiformes, several having already occurred by the late Oligocene.", "keyphrases": ["new family", "diprotodontian marsupial", "late oligocene", "vombatoidea"]}
{"id": "paleo.011433", "title": "A Molecular Phylogeny of Plesiorycteropus Reassigns the Extinct Mammalian Order \u2018Bibymalagasia\u2019", "abstract": "Madagascar is well known for its diverse fauna and flora, being home to many species not found anywhere else in the world. However, its biodiversity in the recent past included a range of extinct enigmatic fauna, such as elephant birds, giant lemurs and dwarfed hippopotami. The \u2018Malagasy aardvark\u2019 (Plesiorycteropus) has remained one of Madagascar\u2019s least well-understood extinct species since its discovery in the 19th century. Initially considered a close relative of the aardvark (Orycteropus) within the order Tubulidentata, more recent morphological analyses challenged this placement on the grounds that the identifiably derived traits supporting this allocation were adaptations to digging rather than shared ancestry. Because the skeletal evidence showed many morphological traits diagnostic of different eutherian mammal orders, they could not be used to resolve its closest relatives. As a result, the genus was tentatively assigned its own taxonomic order \u2018Bibymalagasia\u2019, yet how this order relates to other eutherian mammal orders remains unclear despite numerous morphological investigations. This research presents the first known molecular sequence data for Plesiorycteropus, obtained from the bone protein collagen (I), which places the \u2018Malagasy aardvark\u2019 as more closely related to tenrecs than aardvarks. More specifically, Plesiorycteropus was recovered within the order Tenrecoidea (golden moles and tenrecs) within Afrotheria, suggesting that the taxonomic order \u2018Bibymalagasia\u2019 is obsolete. This research highlights the potential for collagen sequencing in investigating the phylogeny of extinct species as a viable alternative to ancient DNA (aDNA) sequencing, particularly in cases where aDNA cannot be recovered.", "keyphrases": ["phylogeny", "bibymalagasia", "adna"]}
{"id": "paleo.011241", "title": "Million-year-old DNA sheds light on the genomic history of mammoths", "abstract": "Temporal genomic data hold great potential for studying evolutionary processes, including speciation. However, sampling across speciation events would in many cases require genomic time series that stretch well into the Early Pleistocene (>1 million years). Although theoretical models suggest that DNA should survive on this timescale1, the oldest genomic data recovered so far is from a 560-780 ka old horse specimen2. Here we report the recovery of genome-wide data from three Early and Middle Pleistocene mammoth specimens, two of which are more than one million years old. We find that two distinct mammoth lineages were present in eastern Siberia during the Early Pleistocene. One of these gave rise to the woolly mammoth, whereas the other represents a previously unrecognised lineage that was ancestral to the first mammoths to colonise North America. Our analyses reveal that the North American Columbian mammoth traces its ancestry to a Middle Pleistocene hybridisation between these two lineages, with roughly equal admixture proportions. Finally, we show that the majority of protein-coding changes associated with cold adaptation in woolly mammoths were present already a million years ago. These findings highlight the potential of deep time palaeogenomics to expand our understanding of speciation and long-term adaptive evolution.", "keyphrases": ["dna", "mammoth", "early pleistocene", "ancestry"]}
{"id": "10.1126/science.aau5784", "title": "Nitrogen isotope evidence for expanded ocean suboxia in the early Cenozoic", "abstract": "Circulation more than temperature Changes in continental configuration and sea level affected the ocean's oxygen levels and the rate of denitrification between 70 and 30 million years ago. That finding by Kast et al. shows a fundamental difference from the modern ocean, in which the extent of suboxia is controlled primarily by global temperature. Changes in the nitrogen isotopic composition of marine organic matter correlate with the collision of India and Asia and the circulation changes that occurred as a result. Later, isotopic composition changed further in response to a fall in sea level as global cooling caused ice sheets to grow. Science, this issue p. 386 The ocean was more suboxic and supported greater denitrification in the Paleocene than during the Oligocene. The million-year variability of the marine nitrogen cycle is poorly understood. Before 57 million years (Ma) ago, the 15N/14N ratio (\u03b415N) of foraminifera shell-bound organic matter from three sediment cores was high, indicating expanded water column suboxia and denitrification. Between 57 and 50 Ma ago, \u03b415N declined by 13 to 16 per mil in the North Pacific and by 3 to 8 per mil in the Atlantic. The decline preceded global cooling and appears to have coincided with the early stages of the Asia-India collision. Warm, salty intermediate-depth water forming along the Tethys Sea margins may have caused the expanded suboxia, ending with the collision. From 50 to 35 Ma ago, \u03b415N was lower than modern values, suggesting widespread sedimentary denitrification on broad continental shelves. \u03b415N rose at 35 Ma ago, as ice sheets grew, sea level fell, and continental shelves narrowed.", "keyphrases": ["foraminifera", "shell-bound organic matter", "nitrogen"]}
{"id": "10.1126/science.1080475", "title": "High Plant Diversity in Eocene South America: Evidence from Patagonia", "abstract": "Tropical South America has the highest plant diversity of any region today, but this richness is usually characterized as a geologically recent development (Neogene or Pleistocene). From caldera-lake beds exposed at Laguna del Hunco in Patagonia, Argentina, paleolatitude \u223c47\u00b0S, we report 102 leaf species. Radioisotopic and paleomagnetic analyses indicate that the flora was deposited 52 million years ago, the time of the early Eocene climatic optimum, when tropical plant taxa and warm, equable climates reached middle latitudes of both hemispheres. Adjusted for sample size, observed richness exceeds that of any other Eocene leaf flora, supporting an ancient history of high plant diversity in warm areas of South America.", "keyphrases": ["patagonia", "latitude", "high plant diversity"]}
{"id": "10.1073/pnas.0704960104", "title": "Strong coupling of predation intensity and diversity in the Phanerozoic fossil record", "abstract": "The importance of ecological interactions in driving the evolution of animals has been the focus of intense debate among paleontologists, evolutionary biologists, and macroecologists. To test whether the intensity of such interactions covaries with the secular evolutionary trend in global biodiversity, we compiled a species-level database of predation intensity, as measured by the frequency of common predation traces (drillings and repair scars ranging in age from Ediacaran to Holocene). The results indicate that the frequency of predation traces increased notably by the Ordovician, and not in the mid-Paleozoic as suggested by multiple previous studies. Importantly, these estimates of predation intensity and global diversity of marine metazoans correlate throughout the Phanerozoic fossil record regardless of corrections and methods applied. This concordance may represent (i) an ecological signal: long-term coupling of diversity and predation; (ii) a diversity-driven diffusion of predatory behaviors: an increased probability of more complex predatory strategies to appear at higher diversity levels; or (iii) a spurious concordance in signal capture: an artifact where rare species and less-frequent (e.g., trace-producing) predatory behaviors are both more detectable at times when sampling improves. The coupling of predation and diversity records suggests that macroevolutionary and macroecological patterns share common causative mechanisms that may reflect either historical processes or sampling artifacts.", "keyphrases": ["coupling", "predation intensity", "phanerozoic fossil record", "ediacaran"]}
{"id": "paleo.001663", "title": "Body mass predicts isotope enrichment in herbivorous mammals", "abstract": "Carbon isotopic signatures recorded in vertebrate tissues derive from ingested food and thus reflect ecologies and ecosystems. For almost two decades, most carbon isotope-based ecological interpretations of extant and extinct herbivorous mammals have used a single diet\u2013bioapatite enrichment value (14\u2030). Assuming this single value applies to all herbivorous mammals, from tiny monkeys to giant elephants, it overlooks potential effects of distinct physiological and metabolic processes on carbon fractionation. By analysing a never before assessed herbivorous group spanning a broad range of body masses\u2014sloths\u2014we discovered considerable variation in diet\u2013bioapatite \u03b413C enrichment among mammals. Statistical tests (ordinary least squares, quantile, robust regressions, Akaike information criterion model tests) document independence from phylogeny, and a previously unrecognized strong and significant correlation of \u03b413C enrichment with body mass for all mammalian herbivores. A single-factor body mass model outperforms all other single-factor or more complex combinatorial models evaluated, including for physiological variables (metabolic rate and body temperature proxies), and indicates that body mass alone predicts \u03b413C enrichment. These analyses, spanning more than 5 orders of magnitude of body sizes, yield a size-dependent prediction of isotopic enrichment across Mammalia and for distinct digestive physiologies, permitting reconstruction of foregut versus hindgut fermentation for fossils and refined mean annual palaeoprecipitation estimates based on \u03b413C of mammalian bioapatite.", "keyphrases": ["enrichment", "herbivorous mammal", "\u03b413c enrichment", "digestive physiology", "body mass"]}
{"id": "10.4267/2042/53522", "title": "A Cretaceous chronostratigraphic database: construction and applications", "abstract": "Timing and rates of tectonic events, evolutionary processes, and oceanographic and paleoclimatic changes must be based on high-precision numerical age calibration of stages defined in Global Stratotype and Section Points (GSSPs). The Cretaceous Chronostratigraphic Database (CRETCSDB3) is an objective, testable database that calibrates select Cretaceous events and enables high-resolution chronostratigraphic correlations. CRETCSDB3 is a compilation of more than 3500 taxa and marker beds in nearly 300 published sections calibrated to a mega-annum (Ma) scale. The database spans the Jurassic/Cretaceous and the Cretaceous/Paleogene boundaries. Construction of CRETCSDB3 began by plotting bioevents in the Kalaat Senan, Tunisia, Cenomanian-Turonian section to the 1989 time scale. The sedimentology, sequence stratigraphy, and biostratigraphy of this section were precisely documented and stage boundaries defined biostratigraphically. Additional sections with radiometrically dated beds were graphed to constrain the accuracy of the numerical scale. Ranges of first and last occurrences are calibrated to mega-annums of Cretaceous stages defined by GSSPs or reference sections. This database serves as a look-up table for interpolation and age calibration of other stratigraphic sections. The age ranges of some taxa and marker beds are preliminary and may be extended as new sections are added to the database. CRETCSDB3 tested the numeric age calibration of the Albian/Cenomanian boundary. This boundary in North Texas accurately correlates with the GSSP in France by ammonites, planktic foraminifers and dinoflagellates. This stage boundary in North Texas correlates with the 97.88\u00b10.69 Ma Clay Spur Bentonite in Wyoming by sequence stratigraphy and cosmopolitan dinoflagellates. The inconsistency between this age and the current 100.5 Ma date of the 2012 Geologic Time Scale remains to be evaluated independently.", "keyphrases": ["chronostratigraphic database", "database", "ammonites", "dinoflagellate"]}
{"id": "10.1006/qres.2001.2294", "title": "The Climate and Landscape of the Middle Part of the Weichselian Glaciation in Europe: The Stage 3 Project", "abstract": "Abstract Oxygen isotope stage 3 (OIS 3) was a mild interval between the two cold maxima of the last (Weichselian) glaciation marked by climate changes oscillating on a 100\u20131000 yr time scale between near-interglacial and peak-glacial conditions. During OIS 3, modern humans entered Europe, and somewhat later their Neanderthal predecessors became extinct. Our understanding of this momentous event depends on an answer to the question, Did the unstable environmental conditions of the time play a significant role in early human history? The Stage 3 Project is an interdisciplinary study with two main goals: (1) to describe with existing data and to simulate the climates and landscapes of typical warm and cold phases between 45,000 and 30,000 yr ago and (2) to compare the results with the spatial and temporal distribution of human beings in this context. This paper introduces the Stage 3 Project and provides background to a set of papers on the climate and landscape aspects of the Project that will appear in Quaternary Research and to studies of their relevance to the Early Upper Paleolithic of Europe to appear in journals yet to be determined.", "keyphrases": ["landscape", "europe", "climate change"]}
{"id": "10.1098/rspb.2012.2261", "title": "A new stem-neopterygian fish from the Middle Triassic of China shows the earliest over-water gliding strategy of the vertebrates", "abstract": "Flying fishes are extraordinary aquatic vertebrates capable of gliding great distances over water by exploiting their enlarged pectoral fins and asymmetrical caudal fin. Some 50 species of extant flying fishes are classified in the Exocoetidae (Neopterygii: Teleostei), which have a fossil record no older than the Eocene. The Thoracopteridae is the only pre-Cenozoic group of non-teleosts that shows an array of features associated with the capability of over-water gliding. Until recently, however, the fossil record of the Thoracopteridae has been limited to the Upper Triassic of Austria and Italy. Here, we report the discovery of exceptionally well-preserved fossils of a new thoracopterid flying fish from the Middle Triassic of China, which represents the earliest evidence of an over-water gliding strategy in vertebrates. The results of a phylogenetic analysis resolve the Thoracopteridae as a stem-group of the Neopterygii that is more crown-ward than the Peltopleuriformes, yet more basal than the Luganoiiformes. As the first record of the Thoracopteride in Asia, this new discovery extends the geographical distribution of this group from the western to eastern rim of the Palaeotethys Ocean, providing new evidence to support the Triassic biological exchanges between Europe and southern China. Additionally, the Middle Triassic date of the new thoracopterid supports the hypothesis that the re-establishment of marine ecosystems after end-Permian mass extinction is more rapid than previously thought.", "keyphrases": ["middle triassic", "gliding strategy", "vertebrate", "asymmetrical caudal fin", "thoracopteridae"]}
{"id": "paleo.012765", "title": "Hierarchical biota-level and taxonomic controls on the chemistry of fossil melanosomes revealed using synchrotron X-ray fluorescence", "abstract": "Fossil melanosomes, micron-sized granules rich in melanin in vivo, provide key information for investigations of the original coloration, taxonomy and internal anatomy of fossil vertebrates. Such studies rely, in part, on analysis of the inorganic chemistry of preserved melanosomes and an understanding of melanosome chemical taphonomy. The extent to which the preserved chemistry of fossil melanosomes is biased by biotic and abiotic factors is, however, unknown. Here we report the discovery of hierarchical controls on the inorganic chemistry of melanosomes from fossil vertebrates from nine biotas. The chemical data are dominated by a strong biota-level signal, indicating that the primary taphonomic control is the diagenetic history of the host sediment. This extrinsic control is superimposed by a biological, tissue-level control; tissue-specific chemical variation is most likely to survive in fossils where the inorganic chemistry of preserved melanosomes is distinct from that of the host sediment. Comparative analysis of our data for fossil and modern amphibians reveals that most fossil specimens show tissue-specific melanosome chemistries that differ from those of extant analogues, strongly suggesting alteration of original melanosome chemistry. Collectively, these findings form a predictive tool for the identification of fossil deposits with well-preserved melanosomes amenable to studies of fossil colour and anatomy.", "keyphrases": ["control", "chemistry", "melanosome", "fossil vertebrate"]}
{"id": "paleo.004842", "title": "Anatomy and relationships of the fuxianhuiid euarthropod Guangweicaris from the early Cambrian Guanshan Biota in Kunming, Yunnan, Southwest China revisited", "abstract": "The Guanshan Biota (Cambrian Series 2, Stage 4) is a typical Burgess Shale-type biota, and is one of the most significant Cambrian Konservat-Lagerst\u00e4tten from China, in addition to the well-known Chengjiang and Kaili biotas. Guangweicaris is a relatively common arthropod from the Guanshan Biota. Based on new specimens from the Longbaoshan and Xinglongcun sections of the Wulongqing Formation in Kunming, we herein report novel features of Guangweicaris spinatus , such as the eye-bearing anterior sclerite that is associated with the head shield, as well as revised details of the trunk, including the ventral appendages. A detailed comparison of Guangweicaris, Fuxianhuia and Shankouia suggests a close affinity between Guangweicaris and Fuxianhuia , which improves our understanding of the evolution of early Cambrian euarthropods.", "keyphrases": ["euarthropod", "guanshan biota", "guangweicaris spinatus"]}
{"id": "10.1144/sp423.9", "title": "The global Hangenberg Crisis (Devonian\u2013Carboniferous transition): review of a first-order mass extinction", "abstract": "Abstract The global Hangenberg Crisis near the Devonian\u2013Carboniferous boundary (DCB) represents a mass extinction that is of the same scale as the so-called \u2018Big Five\u2019 first-order Phanerozoic events. It played an important role in the evolution of many faunal groups and destroyed complete ecosystems but affected marine and terrestrial environments at slightly different times within a short time span of c. 100\u2013300 kyr. The lower crisis interval in the uppermost Famennian started as a prelude with a minor eustatic sea-level fall, followed rather abruptly by pantropically widespread black shale deposition (Hangenberg Black Shale and equivalents). This transgressive and hypoxic/anoxic phase coincided with a global carbonate crisis and perturbation of the global carbon cycle as evidenced by a distinctive positive carbon isotope excursion, probably as a consequence of climate/salinity-driven oceanic overturns and outer-shelf eutrophication. It is the main extinction level for marine biota, especially for ammonoids, trilobites, conodonts, stromatoporoids, corals, some sharks, and deeper-water ostracodes, but probably also for placoderms, chitinozoans and early tetrapods. Extinction rates were lower for brachiopods, neritic ostracodes, bryozoans and echinoderms. Extinction patterns were similar in widely separate basins of the western and eastern Prototethys, while a contemporaneous marine macrofauna record from high latitudes is missing altogether. The middle crisis interval is characterized by a gradual but major eustatic sea-level fall, probably in the scale of more than 100 m, that caused the progradation of shallow-water siliciclastics (Hangenberg Sandstone and equivalents) and produced widespread unconformities due to reworking and non-deposition. The glacio-eustatic origin of this global regression is proven by miospore correlation with widespread diamictites of South America and South and North Africa, and by the evidence for significant tropical mountain glaciers in eastern North America. This isolated and short-lived plunge from global greenhouse into icehouse conditions may follow the significant drawdown of atmospheric CO2 levels due to the prior massive burial of organic carbon during the global deposition of black shales. Increased carbon recycling by intensified terrestrial erosion in combination with the arrested burial of carbonates may have led to a gradual rise of CO2 levels, re-warming, and a parallel increase in the influx of land-derived nutrients. The upper crisis interval in the uppermost Famennian is characterized by initial post-glacial transgression and a second global carbon isotope spike, as well as by opportunistic faunal blooms and the early re-radiation of several fossil groups. Minor reworking events and unconformities give evidence for continuing smaller-scale oscillations of sea-level and palaeoclimate. These may explain the terrestrial floral change near the Famennian\u2013Tournaisian boundary and contemporaneous, evolutionarily highly significant extinctions of survivors of the main crisis. Still poorly understood small-scale events wiped out the last clymeniid ammonoids, phacopid trilobites, placoderms and some widespread brachiopod and foraminiferan groups. The post-crisis interval in the lower Tournaisian is marked by continuing eustatic rise (e.g. flooding of the Old Red Continent), and significant radiations in a renewed greenhouse time. But the recovery had not yet reached the pre-crisis level when it was suddenly interrupted by the global, second-order Lower Alum Shale Event at the base of the middle Tournaisian.", "keyphrases": ["hangenberg crisis", "mass extinction", "famennian"]}
{"id": "paleo.000070", "title": "Dietary constraints of phytosaurian reptiles revealed by dental microwear textural analysis", "abstract": "Phytosaurs are a group of large, semi\u2010aquatic archosaurian reptiles from the Middle\u2013Late Triassic. They have often been interpreted as carnivorous or piscivorous due to their large size, morphological similarity to extant crocodilians and preservation in fluvial, lacustrine and coastal deposits. However, these dietary hypotheses are difficult to test, meaning that phytosaur ecologies and their roles in Triassic food webs remain incompletely constrained. Here, we apply dental microwear textural analysis to the three\u2010dimensional sub\u2010micrometre scale tooth surface textures that form during food consumption to provide the first quantitative dietary constraints for five species of phytosaur. We furthermore explore the impacts of tooth position and cranial robustness on phytosaur microwear textures. We find subtle systematic texture differences between teeth from different positions along phytosaur tooth rows, which we interpret to be the result of different loading pressures experienced during food consumption, rather than functional partitioning of food processing along tooth rows. We find rougher microwear textures in morphologically robust taxa. This may be the result of seizing and processing larger prey items compared to those captured by gracile taxa, rather than dietary differences per se. We reveal relatively low dietary diversity between our study phytosaurs and that individual species show a lack of dietary specialization. Species are predominantly carnivorous and/or piscivorous, with two taxa exhibiting slight preferences for \u2018harder\u2019 invertebrates. Our results provide strong evidence for higher degrees of ecological convergence between phytosaurs and extant crocodilians than previously appreciated, furthering our understanding of the functioning and evolution of Triassic ecosystems.", "keyphrases": ["reptile", "dental microwear", "tooth position", "dietary constraint"]}
{"id": "paleo.004312", "title": "Understanding modern extinctions in marine ecosystems: the role of palaeoecological data", "abstract": "Because anthropogenic impacts on ecological systems pre-date the oldest scientific observations, historical documents and archaeological records, understanding modern extinctions requires additional data sources that extend further back in time. Palaeoecological records, which provide quantitative proxy records of ecosystems prior to human impact, are essential for understanding recent extinctions and future extinction risks. Here we critically review the value of the most recent fossil record in contributing to our understanding of modern extinctions and illustrate through case studies how naturally occurring death assemblages and Holocene sedimentary records provide context to the plight of marine ecosystems. While palaeoecological data are inherently restricted censuses of past communities (manipulative experiments are not possible), they yield quantitative records over temporal scales that are beyond the reach of ecology. Only by including palaeoecological data is it possible to fully assess the role of long-term anthropogenic processes in driving modern extinction risk.", "keyphrases": ["modern extinction", "marine ecosystem", "palaeoecological data", "ecology", "perspective"]}
{"id": "10.1098/rstb.1998.0231", "title": "Growth and patterning in the conodont skeleton", "abstract": "Recent advances in our understanding of conodont palaeobiology and functional morphology have rendered established hypotheses of element growth untenable. In order to address this problem, hard tissue histology is reviewed paying particular attention to the relationships during growth of the component hard tissues comprising conodont elements, and ignoring a priori assumptions of the homologies of these tissues. Conodont element growth is considered further in terms of the pattern of formation, of which four distinct types are described, all possibly derived from a primitive condition after heterochronic changes in the timing of various developmental stages. It is hoped that this may provide further means of unravelling conodont phylogeny. The manner in which the tissues grew is considered homologous with other vertebrate hard tissues, and the elements appear to have grown in a way similar to the growing scales and growing dentition of other vertebrates.", "keyphrases": ["tissue", "conodont element", "matter", "lamellar crown tissue", "white matter"]}
{"id": "10.1029/2005GC001015", "title": "Impact of biomineralization processes on the Mg content of foraminiferal shells: A biological perspective", "abstract": "The Mg/Ca ratio in foraminiferal shells is widely used as a proxy for paleotemperatures. Nevertheless, it seems that the basic Mg content of foraminifera is determined by biological factors, as can be concluded from the large inter species and intrashell variability and the frequent deviations from inorganic behavior. This paper discusses three possible ways by which foraminifera can control or modify the Mg content in their shell: (1) involvement of organic matrix in the precipitation process that may alter the partition coefficient of Mg in biogenic calcite, (2) controlled conversion of transient amorphous phases to calcite, and (3) modification of the Mg concentration in the parent solution from which the crystals precipitate. The first two mechanisms are probably responsible for the precipitation of high\u2010Mg calcite phases (whole shell or sublayers), while the third mechanism leads to the formation of low\u2010Mg calcite phases. We propose a model adapted from epithelial cells that allows massive Mg2+ removal from the biomineralization site. This model is especially relevant to the planktonic and deep benthic low\u2010Mg foraminifera that are frequently used for paleotemperature reconstructions. We discuss the possible biological roles of Mg in the shell in terms of the calcite polymorph conservation, the in vivo chemical stability of the shell, the functions of Mg as a stabilizer of transient phases and as a controlling agent of the precipitation process. Several temperature sensitive biological processes that may influence the Mg/Ca ratio of the shell are suggested and a model that combines biogenic and inorganic considerations is presented. The model uses Mg heterogeneity in the shell together with temperature response (biologic and inorganic) of biomineralization processes, to account for the deviation of planktonic foraminifera from inorganic calcite at equilibrium with seawater.", "keyphrases": ["biomineralization process", "foraminiferal shell", "deviation", "precipitation"]}
{"id": "paleo.009246", "title": "Early Triassic Marine Biotic Recovery: The Predators' Perspective", "abstract": "Examining the geological past of our planet allows us to study periods of severe climatic and biological crises and recoveries, biotic and abiotic ecosystem fluctuations, and faunal and floral turnovers through time. Furthermore, the recovery dynamics of large predators provide a key for evaluation of the pattern and tempo of ecosystem recovery because predators are interpreted to react most sensitively to environmental turbulences. The end-Permian mass extinction was the most severe crisis experienced by life on Earth, and the common paradigm persists that the biotic recovery from the extinction event was unusually slow and occurred in a step-wise manner, lasting up to eight to nine million years well into the early Middle Triassic (Anisian) in the oceans, and even longer in the terrestrial realm. Here we survey the global distribution and size spectra of Early Triassic and Anisian marine predatory vertebrates (fishes, amphibians and reptiles) to elucidate the height of trophic pyramids in the aftermath of the end-Permian event. The survey of body size was done by compiling maximum standard lengths for the bony fishes and some cartilaginous fishes, and total size (estimates) for the tetrapods. The distribution and size spectra of the latter are difficult to assess because of preservation artifacts and are thus mostly discussed qualitatively. The data nevertheless demonstrate that no significant size increase of predators is observable from the Early Triassic to the Anisian, as would be expected from the prolonged and stepwise trophic recovery model. The data further indicate that marine ecosystems characterized by multiple trophic levels existed from the earliest Early Triassic onwards. However, a major change in the taxonomic composition of predatory guilds occurred less than two million years after the end-Permian extinction event, in which a transition from fish/amphibian to fish/reptile-dominated higher trophic levels within ecosystems became apparent.", "keyphrases": ["mass extinction", "marine reptile", "early triassic", "sauropterygian", "thalattosaur"]}
{"id": "paleo.006508", "title": "Diptera of the middle Eocene Kishenehn Formation. I. Documentation of diversity at the family level", "abstract": "The Coal Creek Member of the Kishenehn Formation in northwestern Montana, USA, is an emerging middle Eocene Lagerst\u00e4tte. While fish, plant, mammal and molluscan fossils are present, the most numerous and well-preserved fossils are those of insects. In this study, we initiate an effort to enumerate, at the family level, the diversity of flies (Insecta: Diptera) at this locality. Seventeen specimens from 17 different families (15 families with Limoniinae and Cylindrotominae within Tipulidae s.l.), 15 new species and three new genera are described. These include Tipula fji sp. nov. (Tipulidae), Ellipteroides kishenehn sp. nov. (Limoniidae), Cyttaromyia lynnae sp. nov. (Cylindrotomidae), Sylvicola silibrarius sp. nov. (Anisopodidae), Efcookella nigra sp. nov. (first fossil known in the genus) (Scatopsidae), Bibiodes kishenehnensis sp. nov. (Bibionidae), Eosciarites hermes gen. et sp. nov. (Sciaridae), Rymosia hypnolithica sp. nov. (Mycetophilidae), Litoleptis araeostylus sp. nov. (Rhagionidae), Kishenehnoasilus bhl gen. et sp. nov. (Asilidae), Drapetis adelomedos sp. nov. (Hybotidae), Salishomyia eocenica gen. et sp. nov. (Dolichopodidae), Agathomyia eocenica sp. nov. (first known fossil in genus) (Platypezidae), Lonchoptera eocenica sp. nov. (Lonchopteridae) and Aenigmatias kishenehnensis sp. nov. (Phoridae). Two specimens in the families Psychodidae and Pipunculidae are described but not assigned to a genus. In addition, we revise several related fossil species housed at the NMNH. Asilopsis fusculus Cockerell, 1921, formerly described in Asilidae, is transferred to Cyttaromyia (Cylindrotomidae) as C. fuscula, Sciara florissantensis Cockerell, 1917 is assigned to Sciaroidea incertae sedis, and Sciara gurnetensis Cockerell, 1916, Sciara lacoei Cockerell, 1915 and Sciara protoberidis Cockerell, 1915, are assigned to Sciaridae incertae sedis. Given their diversity and high degree of preservation, continued characterization of the Coal Creek Member fossils may help elucidate the Eocene radiation of Diptera in North America. GREENWALT ET AL.: KISHENEHN FORMATION DIPTERA 2 Dale E. Greenwalt. Department of Paleobiology, National Museum of Natural History MRC 121, Smithsonian Institution, 10th & Constitution Ave. NW, Washington, D.C. 20013-7012, USA. GreenwaltD@si.edu Daniel J. Bickel. Entomology, Australian Museum, 1 William Street, Sydney NSW 2010, Australia. dan.bickel@austmus.gov.au Peter H. Kerr. Plant Pest Diagnostics Branch, California Department of Food & Agriculture, 3294 Meadowview Road, Sacramento, California 95832-1448, USA. pkerr@cdfa.ca.gov Gregory R. Curler. Mississippi Entomological Museum, Mississippi State University, 100 Old Highway 12, Box 9775, Mississippi 39762-9775, USA. gcurler@gmail.com Brian V. Brown. Entomology Section, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, California 90007, USA. bbrown@nhm.org Herman de Jong. Naturalis Biodiversity Center, Darwinweg 2, 2333 CR Leiden, The Netherlands. Herman.deJong@naturalis.nl Scott J. Fitzgerald. Pacific Northwest Diptera Research Lab, 1460 SW Allen St., Corvallis, Oregon, 97333, USA. woodyfitz@gmail.com Torsten Dikow, Smithsonian Institution, National Museum of Natural History, 10th & Constitution Ave. NW, Washington, DC 20560-0169, USA. dikowt@si.edu Michal Tko\u010d. Department of Entomology, National Museum, Cirkusov\u00e1 1740, CZ-193 00 Praha 9 \u2013 Horn\u00ed Po\u010dernice, Czech Republic. michaltkoc@gmail.com Christian Kehlmaier. Senckenberg Natural History Collections Dresden, Museum of Zoology, K\u00f6nigsbr\u00fccker Landstrasse 159, 01109 Dresden, Germany. kehlmaier@web.de Dalton De Souza Amorim. Departamento de Biologia, Faculdade de Filosofia, Ci\u00eancias e Letras de Ribeir\u00e3o Preto, Universidade de S\u00e3o Paulo, Av. Bandeirantes, 3900, 14040-901, Ribeir\u00e3o Preto, SP, Brazil. dsamorim@usp.br", "keyphrases": ["kishenehn formation", "family level", "northwestern montana", "diptera"]}
{"id": "paleo.000685", "title": "Rodents of the Caribbean: origin and diversification of hutias unravelled by next-generation museomics", "abstract": "The Capromyidae (hutias) are endemic rodents of the Caribbean and represent a model of dispersal for non-flying mammals in the Greater Antilles. This family has experienced severe extinctions during the Holocene and its phylogenetic affinities with respect to other caviomorph relatives are still debated as morphological and molecular data disagree. We used target enrichment and next-generation sequencing of mitochondrial and nuclear genes to infer the phylogenetic relationships of hutias, estimate their divergence ages, and understand their mode of dispersal in the Greater Antilles. We found that Capromyidae are nested within Echimyidae (spiny rats) and should be considered a subfamily thereof. We estimated that the split between hutias and Atlantic Forest spiny rats occurred 16.5 (14.8\u201318.2) million years ago (Ma), which is more recent than the GAARlandia land bridge hypothesis (34\u201335 Ma). This would suggest that during the Early Miocene, an echimyid-like ancestor colonized the Greater Antilles from an eastern South American source population via rafting. The basal divergence of the Hispaniolan Plagiodontia provides further support for a vicariant separation between Hispaniolan and western islands (Bahamas, Cuba, Jamaica) hutias. Recent divergences among these western hutias suggest Plio-Pleistocene dispersal waves associated with glacial cycles.", "keyphrases": ["hutia", "spiny rat", "rodent"]}
{"id": "paleo.007597", "title": "The origin of pterygotid eurypterids (Chelicerata: Eurypterida)", "abstract": "Abstract:\u2002 The Silurian and Lower Devonian pterygotid eurypterids were the largest of all arthropods, but their origin and early evolution are poorly understood. Pterygotus? ventricosus from Kokomo, Indiana, is shown to be the most basal of the pterygotids and constitutes the sister taxon to the rest of the clade. P.? ventricosus has walking appendages similar to those of Slimonia, which is the sister taxon of pterygotids. There is no evidence in P.? ventricosus of the dorsal median pretelson carina characteristic of other pterygotids, but the taxon does have the typical pterygotid undivided genital appendage. The status of the iconic pterygotid character (and presumed synapomorphy), the enlargement of the chelicerae, is uncertain in the Kokomo pterygotid. All the diagnostic characters of pterygotids did not develop simultaneously. A new genus Ciurcopterus is erected to accommodate the Kokomo pterygotid and Pterygotus? sarlei Ciurca and Tetlie.", "keyphrases": ["pterygotid eurypterid", "silurian", "chelicerae"]}
{"id": "paleo.010376", "title": "Temporal Patterns of Nucleotide Misincorporations and DNA Fragmentation in Ancient DNA", "abstract": "DNA that survives in museum specimens, bones and other tissues recovered by archaeologists is invariably fragmented and chemically modified. The extent to which such modifications accumulate over time is largely unknown but could potentially be used to differentiate between endogenous old DNA and present-day DNA contaminating specimens and experiments. Here we examine mitochondrial DNA sequences from tissue remains that vary in age between 18 and 60,000 years with respect to three molecular features: fragment length, base composition at strand breaks, and apparent C to T substitutions. We find that fragment length does not decrease consistently over time and that strand breaks occur preferentially before purine residues by what may be at least two different molecular mechanisms that are not yet understood. In contrast, the frequency of apparent C to T substitutions towards the 5\u2032-ends of molecules tends to increase over time. These nucleotide misincorporations are thus a useful tool to distinguish recent from ancient DNA sources in specimens that have not been subjected to unusual or harsh treatments.", "keyphrases": ["dna fragment", "ancient dna", "fragment length", "frequency", "cytosine deamination"]}
{"id": "10.1080/14772019.2011.565081", "title": "Evolution of morphological disparity in pterosaurs", "abstract": "Pterosaurs were important flying vertebrates for most of the Mesozoic, from the Late Triassic to the end of the Cretaceous (225\u201365 Ma). They varied enormously through time in overall size (with wing spans from about 250 mm to about 12 m), and in features of their cranial and postcranial skeletons. Comparisons of disparity based on discrete cladistic characters show that the basal paraphyletic rhamphorhynchoids (Triassic\u2013Early Cretaceous) occupied a distinct, and relatively small, region of morphospace compared to the derived pterodactyloids (Late Jurassic\u2013Late Cretaceous). This separation is unexpected, especially in view of common constraints on anatomy caused by the requirements of flight. Pterodactyloid disparity shifted through time, with different, small portions of morphospace occupied in the Late Jurassic and Late Cretaceous, and a much larger portion in the Early Cretaceous. This explosion in disparity after 100 Ma of evolution is matched by the highest diversity of the clade: evidently, pterosaurs express a rather \u2018top heavy\u2019 clade shape, and this is reflected in delayed morphological evolution, again an unexpected finding. The expansion of disparity among pterodactyloids was comparable across subclades: pairwise comparisons among the four pterodactyloid superfamilies show that, for the most part, these clades display significant morphological separation, except in the case of Dsungaripteroidea and Azhdarchoidea. Finally, there is no evidence that rhamphorhynchoids as a whole were outcompeted by pterodactyloids, or that pterosaurs were driven to extinction by the rise of birds.", "keyphrases": ["pterosaur", "separation", "flight"]}
{"id": "paleo.005561", "title": "Morphological convergence obscures functional diversity in sabre-toothed carnivores", "abstract": "The acquisition of elongated, sabre-like canines in multiple vertebrate clades during the last 265 Myr represents a remarkable example for convergent evolution. Due to striking superficial similarities in the cranial skeleton, the same or similar skull and jaw functions have been inferred for sabre-toothed species and interpreted as an adaptation to subdue large-bodied prey. However, although some sabre-tooth lineages have been classified into different ecomorphs (dirk-tooths and scimitar-tooths) the functional diversity within and between groups and the evolutionary paths leading to these specializations are unknown. Here, we use a suite of biomechanical simulations to analyse key functional parameters (mandibular gape angle, bending strength, bite force) to compare the functional performance of different groups and to quantify evolutionary rates across sabre-tooth vertebrates. Our results demonstrate a remarkably high functional diversity between sabre-tooth lineages and that different cranial function and prey killing strategies evolved within clades. Moreover, different biomechanical adaptations in coexisting sabre-tooth species further suggest that this functional diversity was at least partially driven by niche partitioning.", "keyphrases": ["functional diversity", "canine", "performance"]}
{"id": "10.1098/rstb.2003.1434", "title": "Responses of Amazonian ecosystems to climatic and atmospheric carbon dioxide changes since the last glacial maximum.", "abstract": "The aims of this paper are to review previously published palaeovegetation and independent palaeoclimatic datasets together with new results we present from dynamic vegetation model simulations and modern pollen rain studies to: (i) determine the responses of Amazonian ecosystems to changes in temperature, precipitation and atmospheric CO2 concentrations that occurred since the last glacial maximum (LGM), ca. 21 000 years ago; and (ii) use this long-term perspective to predict the likely vegetation responses to future climate change. Amazonia remained predominantly forested at the LGM, although the combination of reduced temperatures, precipitation and atmospheric CO2 concentrations resulted in forests structurally and floristically quite different from those of today. Cold-adapted Andean taxa mixed with rainforest taxa in central areas, while dry forest species and lianas probably became important in the more seasonal southern Amazon forests and savannahs expanded at forest-savannah ecotones. Net primary productivity (NPP) and canopy density were significantly lower than today. Evergreen rainforest distribution and NPP increased during the glacial-Holocene transition owing to ameliorating climatic and CO2 conditions. However, reduced precipitation in the Early-Mid-Holocene (ca. 8000-3600 years ago) caused widespread, frequent fires in seasonal southern Amazonia, causing increased abundance of drought-tolerant dry forest taxa and savannahs in ecotonal areas. Rainforests expanded once more in the Late Holocene owing to increased precipitation caused by greater austral summer insolation, although some of this forest expansion (e.g. in parts of the Bolivian Beni) is clearly caused by palaeo Indian landscape modification. The plant communities that existed during the Early-Mid-Holocene may provide insights into the kinds of vegetation response expected from similar increases in temperature and aridity predicted for the twenty-first century. We infer that ecotonal areas near the margins of the Amazon Basin are liable to be most sensitive to future environmental change and should therefore be targeted with conservation strategies that allow 'natural' species movements and plant community re-assortments to occur.", "keyphrases": ["amazonian ecosystem", "glacial maximum", "lgm", "forest"]}
{"id": "10.1017/pab.2016.5", "title": "Axial growth gradients across the postprotaspid ontogeny of the Silurian trilobite Aulacopleura koninckii", "abstract": "Abstract. \n Recent morphometric analysis revealed a juvenile (meraspid) axial growth gradient in the trunk of the \u223c429 Myr old trilobite Aulacopleura koninckii that resulted from growth control based on positional specification, as is common among extant organisms. Here we explore axial growth gradients in the more anterior body region, the cephalon, and in the cephalon and trunk during subsequent development in the holaspid period. We detected an axial growth gradient in the cephalon in the meraspid period, flatter and opposite in direction to that of the trunk, which also persisted during the holaspid period. We also found an holaspid trunk growth gradient, with a different distribution of growth rates among segments than that of the meraspid period. These newly observed growth gradients are compatible with the mechanism of growth control inferred for the meraspid trunk. Thus, the same kind of growth control may have operated in both body regions and during thewhole ontogeny of A. koninckii. This study, alongwith others on the same species that preceded it, show that morphometric analysis of appropriate data sets can address questions of high interest for evolutionary developmental biology using data fromfossils. By revealing developmental features at deep nodes of the phylogenetic tree, these studies will elucidate both how developmental processes evolved and how they themselves affected the evolution of organismal body patterning.", "keyphrases": ["cephalon", "meraspid period", "axial growth gradient"]}
{"id": "paleo.005904", "title": "The evolution of giant flightless birds and novel phylogenetic relationships for extinct fowl (Aves, Galloanseres)", "abstract": "The extinct dromornithids, gastornithids and phorusrhacids are among the most spectacular birds to have ever lived, with some giants exceeding 500\u2009kg. The affinities and evolution of these and other related extinct birds remain contentious, with previous phylogenetic analyses being affected by widespread convergence and limited taxon sampling. We address these problems using both parsimony and tip-dated Bayesian approaches on an expansive taxon set that includes all key extinct flightless and flighted (e.g. Vegavis and lithornithids) forms, an extensive array of extant fowl (Galloanseres), representative Neoaves and palaeognaths. The Paleogene volant Lithornithidae are recovered as stem palaeognaths in the Bayesian analyses. The Galloanseres comprise four clades inferred to have diverged in the Late Cretaceous on Gondwana. In addition to Anseriformes and Galliformes, we recognize a robust new clade (Gastornithiformes) for the giant flightless Dromornithidae (Australia) and Gastornithidae (Eurasia, North America). This clade exhibits parallels to ratite palaeognaths in that flight presumably was lost and giant size attained multiple times. A fourth clade is represented by the Cretaceous Vegavis (Antarctica), which was strongly excluded from Anseriformes; thus, a crucial molecular calibration point needs to be reconsidered. The presbyornithids Wilaru (Australia) and Presbyornis (Northern Hemisphere) are robustly found to be the sister group to Anatoidea (Anseranatidae\u2009+\u2009Anatidae), a relatively more basal position than hitherto recognized. South America's largest bird, Brontornis, is not a galloansere, but a member of Neoaves related to Cariamiformes; therefore, giant Galloanseres remain unknown from this continent. Trait analyses showed that while gigantism and flightlessness evolved repeatedly in groups, diet is constrained by phylogeny: all giant Galloanseres and palaeognaths are herbivores or mainly herbivorous, and giant neoavians are zoophagous or omnivorous.", "keyphrases": ["fowl", "galloansere", "phylogeny"]}
{"id": "paleo.002124", "title": "The last terror birds (Aves, Phorusrhacidae): new evidence from the late Pleistocene of Uruguay", "abstract": "We report new fossil evidence of terror bird survival until the end of the Pleistocene in Uruguay. The new specimens comprise the distal portion of right tarsometatarsus and a left humerus; the latter is assigned to the genus Psilopterus. The sedimentary context of the remains yields a characteristic Pleistocene mammalian association along with numerical age dating giving an undoubted late Pleistocene age (OSL 96,040 \u00b1 6300 years). We also revise and discuss the systematic placement of late Pleistocene phorusrhacid material previously published. The trophic role of terror birds and other South American carnivorous birds in late Pleistocene ecosystems should be revised based on the increasing findings of avianfossil materials.\nPhorusrhacids \u2022 Psilopterinae \u2022 Late Pleistocene \u2022 Uruguay Kurzfassung Wir berichten von neuen fossilen Beweisen f\u00fcr das \u00dcberleben von Terrorv\u00f6geln bis zum Ende des Pleistoz\u00e4ns in Uruguay. Die neuen Exemplare umfassen den distalen Teil des rechten Tarsometatarsus sowie eines linken Humerus; letzterer wird der Gattung Psilopterus zugeordnet. Der sediment\u00e4re Kontext dieser Reste liefert eine charakteristische pleistoz\u00e4ne S\u00e4ugetiergemeinschaft und zusammen mit numerischer Altersdatierung ein unzweifelhaft sp\u00e4t-pleistoz\u00e4nes Alter (OSL 96.040 \u00b1 6.300 Jahre). Wir revidieren und diskutieren au\u00dferdem die systematische Stellung des bisher publizierten sp\u00e4tpleistoz\u00e4nen Phorusrhaciden-Materials. Die trophische Rolle von Terrorv\u00f6geln und anderen s\u00fcdamerikanischen carnivoren V\u00f6geln im \u00d6kosystem des Sp\u00e4t-Pleistoz\u00e4ns sollte, basierend auf der Zunahme der Funde von Vogel-Fossilmaterial, revidiert werden.", "keyphrases": ["terror bird", "pleistocene", "uruguay", "carnivorous bird"]}
{"id": "10.2307/sysbio/28.4.451", "title": "PALEONTOLOGY, PHYLOGENY, AND CLASSIFICATION: AN EXAMPLE FROM THE MAMMALIAN FOSSIL RECORD", "abstract": "Gingerich, P. D. (Museum of Paleontology, The University of Michigan, Ann Arbor, Michigan 48109) 1979. Paleontology, phylogeny, and classification: an example from the mammalian fossil records. Syst. Zool. 28:451-464.-The purpose of a general formal classification of animals is to foster effective communication within and between zoological subdisciplines. Cladistics is a method of classification based only on phylogeny, but knowledge of phylogeny requires a relatively dense and continuous fossil record not available for many groups. Cladistics presumes phylogeny, and it cannot be used to reconstruct phylogeny. Furthermore, phylogenetic relationships are not the only attributes of organisms, and classifications based solely on phylogeny ignore important attributes related to adaption, biogeography, and age. Effective communication requires that a classification be as simple as possible, balanced, and relatively stable. In practice, organisms are grouped into species, and species are grouped into successively higher taxa primarily on the basis of (1) overall similarity (including morphology, geography, and age), with the boundaries between taxa being drawn in such a way that (2) each group is monophyletic in the general sense of this term, with (3) traditional groupings being maintained to the maximum extent consistent with (1) and (2). Classification is basically phenetic, with phylogeny (where known) providing an important constraint on acceptable phenetic arrangements. Traditional and cladistic classifications of North American Eocene primates of the family Adapidae are compared, with a slightly modified traditional classification being favored because of its simplicity, balance, and stability. Phylogeny itself is better expressed in a diagram than in a formal classification. [Classification; phylogeny; stratophenetics; cladistics; Adapidae.] Classification occupies a curious position in zoology. The most interesting aspects of animal biology are develop", "keyphrases": ["phylogeny", "mammalian fossil record", "paleontology"]}
{"id": "10.1002/jmor.21067", "title": "A reassessment of the cranial morphology of Neoepiblema acreensis (Rodentia: Chinchilloidea), a Miocene rodent from South America", "abstract": "The rodent Neoepiblema acreensis (Chinchilloidea: Neoepiblemidae) is member of a lineage that reached gigantic dimensions during the Late Miocene of South America\u2014the Neoepiblemidae. In this paper, the cranial anatomy of this rodent is reviewed. Noninvasive imaging is used to reveal internal structures. Our review is based mainly on an almost complete cranium from the Upper Miocene deposits of the western Amazonia of Brazil. The cranium has an elongated rostrum, large frontal sinuses, a deep temporal fossa, well\u2010developed sagittal, nuchal, medial occipital, and secondary crests, and a tympanic fenestra connected to the external acoustic meatus by a thin ventral cleft. Remarkably, the cranium shows the presence of fossae on the posterior region of the frontal and parietal bones, and a \u201cW\u2010shaped\u201d fronto\u2010parietal suture, which are not present in other analyzed chinchilloids. This study contributes to the knowledge of the morphology of this extinct rodent as well as to the phylogenetic relationships and paleobiology of neoepiblemids.", "keyphrases": ["morphology", "neoepiblema acreensis", "chinchilloidea"]}
{"id": "paleo.005864", "title": "Breeding Young as a Survival Strategy during Earth\u2019s Greatest Mass Extinction", "abstract": "Studies of the effects of mass extinctions on ancient ecosystems have focused on changes in taxic diversity, morphological disparity, abundance, behaviour and resource availability as key determinants of group survival. Crucially, the contribution of life history traits to survival during terrestrial mass extinctions has not been investigated, despite the critical role of such traits for population viability. We use bone microstructure and body size data to investigate the palaeoecological implications of changes in life history strategies in the therapsid forerunners of mammals before and after the Permo-Triassic Mass Extinction (PTME), the most catastrophic crisis in Phanerozoic history. Our results are consistent with truncated development, shortened life expectancies, elevated mortality rates and higher extinction risks amongst post-extinction species. Various simulations of ecological dynamics indicate that an earlier onset of reproduction leading to shortened generation times could explain the persistence of therapsids in the unpredictable, resource-limited Early Triassic environments, and help explain observed body size distributions of some disaster taxa (e.g., Lystrosaurus). Our study accounts for differential survival in mammal ancestors after the PTME and provides a methodological framework for quantifying survival strategies in other vertebrates during major biotic crises.", "keyphrases": ["survival strategy", "lystrosaurus", "early onset"]}
{"id": "paleo.004994", "title": "The oldest record of ornithuromorpha from the early cretaceous of China", "abstract": "Ornithuromorpha is the most inclusive clade containing extant birds but not the Mesozoic Enantiornithes. The early evolutionary history of this avian clade has been advanced with recent discoveries from Cretaceous deposits, indicating that Ornithuromorpha and Enantiornithes are the two major avian groups in Mesozoic. Here we report on a new ornithuromorph bird, Archaeornithura meemannae gen. et sp. nov., from the second oldest avian-bearing deposits (130.7 Ma) in the world. The new taxon is referable to the Hongshanornithidae and constitutes the oldest record of the Ornithuromorpha. However, A. meemannae shows few primitive features relative to younger hongshanornithids and is deeply nested within the Hongshanornithidae, suggesting that this clade is already well established. The new discovery extends the record of Ornithuromorpha by five to six million years, which in turn pushes back the divergence times of early avian lingeages into the Early Cretaceous.", "keyphrases": ["ornithuromorpha", "early cretaceous", "old record", "furcula"]}
{"id": "paleo.008715", "title": "A new developmental mechanism for the separation of the mammalian middle ear ossicles from the jaw", "abstract": "Multiple mammalian lineages independently evolved a definitive mammalian middle ear (DMME) through breakdown of Meckel's cartilage (MC). However, the cellular and molecular drivers of this evolutionary transition remain unknown for most mammal groups. Here, we identify such drivers in the living marsupial opossum Monodelphis domestica, whose MC transformation during development anatomically mirrors the evolutionary transformation observed in fossils. Specifically, we link increases in cellular apoptosis and TGF-BR2 signalling to MC breakdown in opossums. We demonstrate that a simple change in TGF-\u03b2 signalling is sufficient to inhibit MC breakdown during opossum development, indicating that changes in TGF-\u03b2 signalling might be key during mammalian evolution. Furthermore, the apoptosis that we observe during opossum MC breakdown does not seemingly occur in mouse, consistent with homoplastic DMME evolution in the marsupial and placental lineages.", "keyphrases": ["mammalian middle ear", "jaw", "cartilage", "mandible"]}
{"id": "10.1130/B31167.1", "title": "Triggering of the largest Deccan eruptions by the Chicxulub impact", "abstract": "New constraints on the timing of the Cretaceous-Paleogene mass extinction and the Chicxulub impact, together with a particularly voluminous and apparently brief eruptive pulse toward the end of the \u201cmain-stage\u201d eruptions of the Deccan continental fl ood basalt province suggest that these three events may have occurred within less than about a hundred thousand years of each other. Partial melting induced by the Chicxulub event does not provide an energetically plausible explanation for this coincidence, and both geochronologic and magnetic-polarity data show that Deccan volcanism was under way well before Chicxulub/Cretaceous-Paleogene time. However, historical data document that eruptions from existing volcanic systems can be triggered by earthquakes. Seismic modeling of the ground motion due to the Chicxulub impact suggests that the impact could have generated seismic energy densities of order 0.1\u20131.0 J/m 3 throughout the upper ~200 km of Earth\u2019s mantle, suffi cient to trigger volcanic eruptions worldwide based upon comparison with historical examples. Triggering may have been caused by a transient increase in the effective permeability of the existing deep magmatic system beneath the Deccan province, or mantle plume \u201chead.\u201d It is therefore reasonable to hypothesize that the Chicxulub impact might have triggered the enormous Poladpur, Ambenali, and Mahabaleshwar (Wai Subgroup) lava fl ows, which together may account for >70% of the Deccan Traps main-stage eruptions. This hypothesis is consistent with independent stratigraphic, geochronologic, geochemical, and tectonic constraints, which combine to indicate that at approximately Chicxulub/Cretaceous-Paleogene time, a huge pulse of mantle plume\u2013derived magma passed through the crust with little interaction and erupted to form the most extensive and voluminous lava fl ows known on Earth. High-precision radioisotopic dating of the main-phase Deccan fl ood basalt formations may be able either to confi rm or reject this hypothesis, which in turn might help to determine whether this singular outburst within the Deccan Traps (and possibly volcanic eruptions worldwide) contributed signifi cantly to the CretaceousPaleogene extinction.", "keyphrases": ["eruption", "chicxulub impact", "deccan traps"]}
{"id": "10.1002/2016PA003073", "title": "Spatiotemporal variability in the \u03b418O-salinity relationship of seawater across the tropical Pacific Ocean.", "abstract": "The relationship between salinity and the stable oxygen isotope ratio of seawater (\u03b418Osw) is of utmost importance to the quantitative reconstruction of past changes in salinity from \u03b418O values of marine carbonates. This relationship is often considered to be uniform across water masses, but the constancy of the \u03b418Osw-salinity relationship across space and time remains uncertain, as \u03b418Osw responds to varying atmospheric vapor sources and pathways, while salinity does not. Here we present new \u03b418Osw-salinity data from sites spanning the tropical Pacific Ocean. New data from Palau, Papua New Guinea, Kiritimati, and Gal\u00e1pagos show slopes ranging from 0.09 \u2030/psu in the Gal\u00e1pagos to 0.32\u2030/psu in Palau. The slope of the \u03b418Osw-salinity relationship is higher in the western tropical Pacific versus the eastern tropical Pacific in observations and in two isotope-enabled climate models. A comparison of \u03b418Osw-salinity relationships derived from short-term spatial surveys and multi-year time series at Papua New Guinea and Gal\u00e1pagos suggests spatial relationships can be substituted for temporal relationships at these sites, at least within the time period of the investigation. However, the \u03b418Osw-salinity relationship varied temporally at Palau, likely in response to water mass changes associated with interannual El Ni\u00f1o-Southern Oscillation (ENSO) variability, suggesting nonstationarity in this local \u03b418Osw-salinity relationship. Applying local \u03b418Osw-salinity relationships in a coral \u03b418O forward model shows that using a constant, basin-wide \u03b418Osw-salinity slope can both overestimate and underestimate the contribution of \u03b418Osw to carbonate \u03b418O variance at individual sites in the western tropical Pacific.", "keyphrases": ["variability", "tropical pacific", "pacific ocean"]}
{"id": "10.1017/S009483730001397X", "title": "Shape, Drag, and Power in Ammonoid Swimming", "abstract": "This study assesses swimming potential in a variety of ammonoid shell shapes on the basis of coefficients of drag (Cd) and the power needed to maintain a constant velocity. Reynolds numbers (Re) relevant to swimming ammonoids, and lower than those previously studied, were examined. Power consumption was scaled to a range of sizes and swimming velocities. Estimates of power available derived from studies of oxygen consumption in modern cephalopods and fish were used to calculate maximum sustainable swimming velocities (MSV). Laterally compressed, small thickness ratio (t. r.) ammonoids, previously assumed to be the most efficient swimmers, do not experience the lowest drag or power consumption at all sizes and velocities. At low values of size and velocity associated with Reynolds numbers below 104, less compressed forms have smaller drag coefficients and reduced power requirements. At hatching a roughly spherical shell shape would have minimized drag in ammonoids; with increasing size, hydrodynamic optima shift toward compressed morphologies. The high energetic cost of ammonoid locomotion may have limited dispersal and excluded ammonoids from high current velocity environments.", "keyphrases": ["drag", "power", "shell shape", "ammonoid locomotion"]}
{"id": "10.1017/S1477201908002605", "title": "Skull anatomy of Dakosaurus andiniensis (Thalattosuchia: Crocodylomorpha) and the phylogenetic position of Thalattosuchia", "abstract": "Synopsis New information on Dakosaurus andiniensis from the Latest Jurassic and Early Cretaceous is reported here. One of the specimens described herein consists of an almost complete skull and lower jaw found in the uppermost levels of the Vaca Muerta Formation (Tithonian) of Neuqu\u00e9n Province, Argentina. The new material allows a more complete understanding and diagnosis of this form, previously known only from the fragmentary type specimen. The new remains show that D. andiniensis had an unusual morphology for a marine crocodyliform,namely a remarkably short, high snout with ziphodont dentition. This new information allows testing of the phylogenetic relationships of this taxon, which is depicted as deeply nested within Metriorhynchidae, a clade of marine crocodyliforms with derived adaptations to the marine environment (e.g. paddle\u2010like forelimbs, hypertrophied nasal salt glands). In particular, D. andiniensis is inferred to be the sister taxon of D. maximus from the Jurassic of Europe. This relationship repeats the phylogenetic pattern seen in other Jurassic marine crocodyliforms from South America and Europe (e.g. Geosaurus), demonstrating the close faunal relationship between these two distant marine basins. The phylogenetic analysis reported here results in a most parsimonious hypothesis that depicts Thalattosuchia nested within Neosuchia and the strength and character evidence supporting this position is presented. In addition, several characters traditionally postulated as dependent upon the longirostrine morphology are critically examined under the light of new evidence. Most of them show a character state distribution that is not strictly compatible with that of the longirostrine condition and, therefore, are interpreted as independent units of phylogenetic evidence.", "keyphrases": ["dakosaurus andiniensis", "thalattosuchia", "early cretaceous"]}
{"id": "10.1111/j.1475-4983.2010.01006.x", "title": "The anatomy, taphonomy, taxonomy and systematic affinity of Markuelia: Early Cambrian to Early Ordovician scalidophorans", "abstract": "Abstract:\u2002 Markuelia is a vermiform, annulated introvertan animal known as embryonic fossils from the Lower Cambrian to Lower Ordovician. Analysis of an expanded and revised dataset for Introverta shows that the precise position of Markuelia within this clade is dependent on the taxa included. As a result, Markuelia is assigned to the scalidophoran total group to reflect uncertainty as to whether it is a stem\u2010scalidophoran or a stem\u2010priapulid. The taxonomy of the genus is revised to provide an improved taxonomic framework for material assigned to Markuelia. Five species are recognized: M. secunda Val\u2019kov, M. hunanensis Dong and Donoghue, M. lauriei Haug et al., M. spinulifera sp. nov. and M.\u2003waloszeki sp. nov. Finally, the preservation of Markuelia is evaluated in the light of both the taphonomy of the fossil embryos themselves and the experimental taphonomy of the priapulid Priapulus caudatus, which has been proposed as both a close relative and an anatomical analogue of Markuelia.", "keyphrases": ["taphonomy", "markuelia", "ordovician", "scalidophoran"]}
{"id": "paleo.005879", "title": "The monophyly of Euparkeriidae (Reptilia: Archosauriformes) and the origins of Archosauria: a revision of Dorosuchus neoetus from the Mid\u2010Triassic of Russia", "abstract": "Euparkeria capensis is resolved as the sister taxon to Archosauria in many cladistic phylogenies and provides a key outgroup which may approximate the ancestral archosaur morphology. Several other taxa have been referred to the family Euparkeriidae, but the monophyly of this taxon remains doubtful and largely untested. To test this monophyly, the archosauriform and putative euparkeriid Dorosuchus neoetus from the Mid\u2010Triassic of Russia is re\u2010examined in the light of recent work on the evolution of stem archosaurs. Dorosuchus neoetus is found to possess a number of morphological features that place it close to Archosauria, including a sigmoidal femur with a clear attachment region for the m. caudifemoralis musculature, but no unambiguous archosaurian apomorphies. Dorosuchus neoetus is included for the first time in a numerical cladistic analysis and is recovered as the sole sister taxon to Archosauria + Phytosauria. A monophyletic Euparkeriidae including D. neoetus and E. capensis is slightly less parsimonious. In addition, a mandible and pterygoid that were previously referred to D. neoetus subsequent to the original description of the species are also included separately within the phylogenetic analysis and are recovered within Archosauria, possibly raising questions as to their correct taxonomic referral. However, this phylogenetic placement is based primarily on the absence of palatal teeth, but the presence or absence of palatal teeth exhibits considerable homoplasy within Archosauriformes. Based on other aspects of their morphology, we do not reject the referral of these elements to D. neoetus.", "keyphrases": ["monophyly", "euparkeriidae", "archosauria", "sister"]}
{"id": "paleo.006902", "title": "Injured trilobites within a collection of dinosaurs: Using the Royal Tyrrell Museum of Palaeontology to document Cambrian predation", "abstract": "Biomineralised exoskeletons of trilobites are ideal for recording abnormalities, documenting injuries from failed attacks, and understanding predation in the fossil record. The illustration of new injured Cambrian-aged trilobites is particularly important for elucidating aspects of early Paleozoic predator-prey systems and identifying groups that were targets of this early predation. We document six new abnormal trilobite specimens from the Royal Tyrrell Museum of Palaeontology, including the first evidence for injuries on the corynexochid trilobite Hemirhodon amplipyge. These new data highlight the importance of museum collections in uncovering unique and informative specimens for studies of predation on early animals. Russell D. C. Bicknell. Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia. rdcbicknell@gmail.com Brayden Holland. Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, 2351, Australia. blongle2@myune.edu.au", "keyphrases": ["royal tyrrell museum", "palaeontology", "predation", "injury"]}
{"id": "paleo.007844", "title": "The Braincase of the Basal Sauropod Dinosaur Spinophorosaurus and 3D Reconstructions of the Cranial Endocast and Inner Ear", "abstract": "Background Sauropod dinosaurs were the largest animals ever to walk on land, and, as a result, the evolution of their remarkable adaptations has been of great interest. The braincase is of particular interest because it houses the brain and inner ear. However, only a few studies of these structures in sauropods are available to date. Because of the phylogenetic position of Spinophorosaurus nigerensis as a basal eusauropod, the braincase has the potential to provide key evidence on the evolutionary transition relative to other dinosaurs. Methodology/Principal Findings The only known braincase of Spinophorosaurus (\u2018Argiles de l'Irhazer\u2019, Irhazer Group; Agadez region, Niger) differs significantly from those of the Jurassic sauropods examined, except potentially for Atlasaurus imelakei (Tilougguit Formation, Morocco). The basisphenoids of Spinophorosaurus and Atlasaurus bear basipterygoid processes that are comparable in being directed strongly caudally. The Spinophorosaurus specimen was CT scanned, and 3D renderings of the cranial endocast and inner-ear system were generated. The endocast resembles that of most other sauropods in having well-marked pontine and cerebral flexures, a large and oblong pituitary fossa, and in having the brain structure obscured by the former existence of relatively thick meninges and dural venous sinuses. The labyrinth is characterized by long and proportionally slender semicircular canals. This condition recalls, in particular, that of the basal non-sauropod sauropodomorph Massospondylus and the basal titanosauriform Giraffatitan. Conclusions/Significance Spinophorosaurus has a moderately derived paleoneuroanatomical pattern. In contrast to what might be expected early within a lineage leading to plant-eating graviportal quadrupeds, Spinophorosaurus and other (but not all) sauropodomorphs show no reduction of the vestibular apparatus of the inner ear. This character-state is possibly a primitive retention in Spinophorosaurus, but due the scarcity of data it remains unclear whether it is also the case in the various later sauropods in which it is present or whether it has developed homoplastically in these taxa. Any interpretations remain tentative pending the more comprehensive quantitative analysis underway, but the size and morphology of the labyrinth of sauropodomorphs may be related to neck length and mobility, among other factors.", "keyphrases": ["braincase", "spinophorosaurus", "cranial endocast", "inner ear"]}
{"id": "paleo.000065", "title": "New Australian sauropods shed light on Cretaceous dinosaur palaeobiogeography", "abstract": "Australian dinosaurs have played a rare but controversial role in the debate surrounding the effect of Gondwanan break-up on Cretaceous dinosaur distribution. Major spatiotemporal gaps in the Gondwanan Cretaceous fossil record, coupled with taxon incompleteness, have hindered research on this effect, especially in Australia. Here we report on two new sauropod specimens from the early Late Cretaceous of Queensland, Australia, that have important implications for Cretaceous dinosaur palaeobiogeography. Savannasaurus elliottorum gen. et sp. nov. comprises one of the most complete Cretaceous sauropod skeletons ever found in Australia, whereas a new specimen of Diamantinasaurus matildae includes the first ever cranial remains of an Australian sauropod. The results of a new phylogenetic analysis, in which both Savannasaurus and Diamantinasaurus are recovered within Titanosauria, were used as the basis for a quantitative palaeobiogeographical analysis of macronarian sauropods. Titanosaurs achieved a worldwide distribution by at least 125 million years ago, suggesting that mid-Cretaceous Australian sauropods represent remnants of clades which were widespread during the Early Cretaceous. These lineages would have entered Australasia via dispersal from South America, presumably across Antarctica. High latitude sauropod dispersal might have been facilitated by Albian\u2013Turonian warming that lifted a palaeoclimatic dispersal barrier between Antarctica and South America.", "keyphrases": ["sauropod", "cretaceous dinosaur palaeobiogeography", "australia", "palaeolatitude", "dorsal vertebrae"]}
{"id": "10.1130/0-8137-2369-8.79", "title": "Estimating Latest Cretaceous and Tertiary atmospheric CO2 from stromatal indices", "abstract": "A quantitative understanding of the levels of atmospheric CO2 in the geologic past sheds light on the operation of the carbon cycle and the biosphere, and aids in the prediction of future climate change. Here I present a CO2 reconstruction for the very latest Cretaceous to early Eocene and middle Miocene based on the stomatal distributions in fossil and extant Ginkgo and Metasequoia cuticles. Although both of these intervals are representative of globally warm climates, my CO2 reconstruction indicates near present-day values (300\u2013450 ppmV) for both times. Although these data do not cast doubt on the theory of the greenhouse effect, they do suggest that other thermal forcings were more important during these intervals than they are today. 79 Royer, D.L., 2003, Estimating latest Cretaceous and Tertiary atmospheric CO2 from stomatal indices, in Wing, S.L., Gingerich, P.D., Schmitz, B., and Thomas, E., eds., Causes and Consequences of Globally Warm Climates in the Early Paleogene: Boulder, Colorado, Geological Society of America Special Paper 369, p. 79\u201393. \u00a9 2003 Geological Society of America. *E-mail: droyer@psu.edu. Present address: Department of Geosciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA. Royer, 2001). Stomatal index (SI) is the percentage of epidermal cells that are stomatal complexes (guard cells + stomatal pore), and is defined as the following (Salisbury, 1927): SD SI = ________ \u00d7 100 SD + ED where SD = stomatal density (mm\u20132) and ED = epidermal cell density (mm\u20132). The mechanism(s) linking CO2 to SI is not fully understood, but probably involves the strong selective pressure in plants to maximize carbon fixation per unit of water transpired (water-use efficiency) (e.g., Woodward, 1987). For example, in a rising CO2 regime plants can increase their wateruse efficiency by reducing their stomatal conductance, thereby reducing water loss. Stomatal conductance is largely a function of stomatal pore area, which in turn is controlled by the size of individual stomatal pores and the density of those pores. On the time scale of several growing seasons or longer, stomatal density is typically more sensitive to changes in atmospheric CO2 than individual pore size (e.g., Royer, 2001). Furthermore, on multimillion year time scales stomatal density and SI across all plant taxa inversely respond to CO2 (Beerling and Woodward, 1997; McElwain, 1998; Royer, 2001). In contrast to stomatal density, SI is area independent, which normalizes for the effects of cell expansion. Stomatal index is essentially a measure of the number of stomatal complexes that develop per unit number of epidermal cells. Plant water-potential strongly influences cell expansion (e.g., water stressed plants generally reduce the size of their epidermal cells [Royer, 2001]), but not the rate of stomatal initialization. Thus, changes in a plant\u2019s water budget can affect stomatal density, but not stomatal index. Both experimental and field studies show that SI is largely independent of water potential, irradiance, and temperature, and is primarily a function of CO2 (e.g., K\u00fcrschner et al., 1998; Beerling, 1999; Royer, 2001). Stomatal indices (and stomatal densities) have been experimentally shown to respond to the partial pressure of CO2, not concentration (as expressed as mole fraction, e.g., parts per million) (Woodward and Bazzaz, 1988). This finding is corroborated by a positive correlation in many plants between elevation and stomatal density (K\u00f6rner and Cochrane, 1985; Woodward, 1986; Woodward and Bazzaz, 1988; Beerling et al., 1992) and SI (Rundgren and Beerling, 1999). It is important, therefore, to control for elevation when estimating CO2 from stomatal properties. The relationship between elevation and partial pressure in the lower atmosphere is roughly as follows (linear fit to equation 11.8 in Jones, 1992, p. 308):", "keyphrases": ["tertiary atmospheric co2", "stomatal index", "index"]}
{"id": "10.1111/gbi.12182", "title": "Oceanic oxygenation events in the anoxic Ediacaran ocean", "abstract": "The ocean\u2010atmosphere system is typically envisioned to have gone through a unidirectional oxygenation with significant oxygen increases in the earliest (ca. 635 Ma), middle (ca. 580 Ma), or late (ca. 560 Ma) Ediacaran Period. However, temporally discontinuous geochemical data and the patchy metazoan fossil record have been inadequate to chart the details of Ediacaran ocean oxygenation, raising fundamental debates about the timing of ocean oxygenation, its purported unidirectional rise, and its causal relationship, if any, with the evolution of early animal life. To better understand the Ediacaran ocean redox evolution, we have conducted a multi\u2010proxy paleoredox study of a relatively continuous, deep\u2010water section in South China that was paleogeographically connected with the open ocean. Iron speciation and pyrite morphology indicate locally euxinic (anoxic and sulfidic) environments throughout the Ediacaran in this section. In the same rocks, redox sensitive element enrichments and sulfur isotope data provide evidence for multiple oceanic oxygenation events (OOEs) in a predominantly anoxic global Ediacaran\u2013early Cambrian ocean. This dynamic redox landscape contrasts with a recent view of a redox\u2010static Ediacaran ocean without significant change in oxygen content. The duration of the Ediacaran OOEs may be comparable to those of the oceanic anoxic events (OAEs) in otherwise well\u2010oxygenated Phanerozoic oceans. Anoxic events caused mass extinctions followed by fast recovery in biologically diversified Phanerozoic oceans. In contrast, oxygenation events in otherwise ecologically monotonous anoxic Ediacaran\u2013early Cambrian oceans may have stimulated biotic innovations followed by prolonged evolutionary stasis.", "keyphrases": ["oxygenation event", "anoxic", "ediacaran ocean", "oceanic oxygenation event"]}
{"id": "paleo.004176", "title": "Craniodental and humeral morphology of a new species of Masrasector (Teratodontinae, Hyaenodonta, Placentalia) from the late Eocene of Egypt and locomotor diversity in hyaenodonts", "abstract": "Hyaenodonta is a diverse clade of carnivorous mammals that were part of terrestrial faunas in the Paleogene of Eurasia and North America, but the oldest record for the group is Afro-Arabian, making the record there vital for understanding the evolution of this wide-spread group. Previous studies show an ancient split between two major clades of hyaenodonts that converged in hypercarnivory: Hyainailourinae and Hyaenodontinae. These clades are each supported by cranial characters. Phylogenetic analyses of hyaenodonts also support the monophyly of Teratodontinae, an Afro-Arabian clade of mesocarnivorous to hypercarnivorous hyaenodonts. Unfortunately, the cranial anatomy of teratodontines is poorly known, and aligning the clade with other lineages has been difficult. Here, a new species of the phylogenetically controversial teratodontine Masrasector is described from Locality 41 (latest Priabonian, late Eocene) from the Fayum Depression, Egypt. The hypodigm includes the most complete remains of a Paleogene teratodontine, including largely complete crania, multiple dentaries, and isolated humeri. Standard and \u201ctip-dating\u201d Bayesian analyses of a character-taxon matrix that samples cranial, postcranial, and dental characters support a monophyletic Masrasector within Teratodontinae, which is consistently placed as a close sister group of Hyainailouridae. The cranial morphology of Masrasector provides new support for an expanded Hyainailouroidea (Teratodontinae + Hyainailouridae), particularly characters of the nuchal crest, palate, and basicranium. A discriminant function analysis was performed using measurements of the distal humerus from a diverse sample of extant carnivorans to infer the locomotor habits of Masrasector. Masrasector was assigned to the \u201cterrestrial\u201d locomotor category, a result consistent with the well-defined medial trochlear ridges, and moderately developed supinator crests of the specimens. Masrasector appears to have been a fast-moving terrestrial form with a diverse diet. These specimens considerably improve our understanding of Teratodontinae, an ancient member of the Afro-Arabian mammalian fauna, and our understanding of hyaenodont diversity before the dispersal of Carnivora to the continent near the end of the Paleogene.", "keyphrases": ["morphology", "hyaenodonta", "late eocene", "phylogenetic analysis"]}
{"id": "10.1666/0094-8373-39.1.75", "title": "Intraspecific variability through ontogeny in early ammonoids", "abstract": "Abstract Mollusks in general and ammonoids in particular are known to display a sometimes profound morphological intraspecific variability of their shell. Although this phenomenon is of greatest importance, it has rarely been investigated and quantified. It is especially crucial for taxonomy and incidentally for biodiversity analyses to account for it, because otherwise, the number of described species might exceed that of actual species within any group. Early ammonoids (Early Devonian, Paleozoic) typically suffer from this bias. For instance, most specimens from the same layer and the same region (e.g., the Erbenoceras beds of the Moroccan eastern Anti-Atlas studied here) differ morphologically from each other. Depending on the importance given to certain morphological characters, therefore, one could create a new species for almost every specimen. In this study, we measured nearly 100 such specimens from a restricted stratigraphic interval and quantified their intraspecific variability. There is a variable but strong overlap of the quantified shell characters at most ontogenetic stages, and only two species are here separated rather than the four previously recognized in Morocco. When ontogenetic trajectories of the Moroccan specimens are compared with coeval faunas from other regions (assigned to other species), a strong overlap between the morphospaces occupied by these taxa becomes apparent. The justification of some of these latter species is thus questionable even if their mean values in some conch parameters differ considerably from the mean values of the Moroccan species. Hence, the number of currently valid species of these loosely coiled early ammonoids is probably much too high. Extreme caution must therefore be taken when examining the diversity of groups in which the intraspecific variability is poorly known.", "keyphrases": ["ontogeny", "ammonoid", "overlap", "intraspecific variability"]}
{"id": "10.1126/science.175.4024.894", "title": "Breakup of Pangaea and Isolation of Relict Mammals in Australia, South America, and Madagascar", "abstract": "The composition of aboriginal land mammal faunas in Australia and New Guinea (prototherians and metatherians), South America (metatherians and eutherians) and Madagascar (eutherians only) is reconsidered in light of continental drift reconstructions of Mesozoic-Tertiary world paleogeography It is proposed that these three faunas represent successively detached samples of the evolving world mammal fauna as it existed when each of these land masses became faunally isolated from the rest of the world as a result of the progressive fragmentation of Pangaea. Isolation of aboriginal prototherians and metatherians in Australia and New Guinea may date from the Upper JurassicLower Cretaceous; isolation of aboriginal metatherians and eutherians in South America may date from the Middle Cretaceous-Upper Cretaceous; isolation of aboriginal eutherians in Madagascar may date from the Paleocene-Eocene.", "keyphrases": ["pangaea", "south america", "mammal fauna"]}
{"id": "paleo.008243", "title": "Sedimentary factories and ecosystem change across the Permian-Triassic Critical Interval (P-TrCI) \u2013 insights from the Xiakou area (South China)", "abstract": "The Permian-Triassic mass extinction included a potentially catastrophic decline of biodiversity, but ecosystem change across this event remains poorly characterized. Here we reconstruct sedimentary factories and ecosystem change across the Permian-Triassic Critical Interval (P-TrCI) in the Xiakou area (South China). Six microfacies (MF) were classified. The succession begins with a eukaryote-controlled carbonate factory (MF-1) that passes upward into an organomineralizationdominated carbonate factory (MF-2-3). Organic-rich marls atop these units reflect carbonate factory collapse (MF-4). Organomineralization-driven carbonate formation restarts prior to the Permian-Triassic boundary (MF-5) and subsequently develops into a mixed carbonate factory where organomineralization and biomineralization are almost equally important (MF-6). MF-1 reflects oxygenated shallow water environments. In contrast, MF-2-6 were all deposited in somewhat deeper environments, some of which episodically exhibited elevated salinities, oxygen depletion, and, possibly, euxinic conditions. Our results demonstrate that distinct changes in carbonate production styles, biodiversity, and environmental conditions are not synchronous at Xiakou. Furthermore, the Xiakou record is strikingly different to that of other localities, even from the same area (e.g., the Global Stratotype Section and Point section at Meishan). Together, these findings highlight the enormous complexity of the P-TrCI and calls simplified views of the Permian-Triassic mass extinction into question.", "keyphrases": ["ecosystem change", "south china", "permian-triassic boundary", "sedimentary factory"]}
{"id": "paleo.013124", "title": "Calcium isotopic patterns in enamel reflect different nursing behaviors among South African early hominins", "abstract": "Calcium isotopic ratios in dental enamel of South African hominins reveal taxon-dependent nursing behaviors. Nursing is pivotal in the social and biological evolution of hominins, but to date, early-life behavior among hominin lineages is a matter of debate. The calcium isotopic compositions (\u03b444/42Ca) of tooth enamel can provide dietary information on this period. Here, we measure the \u03b444/42Ca values in spatially located microsized regions in tooth enamel of 37 South African hominins to reconstruct early-life dietary-specific variability in Australopithecus africanus, Paranthropus robustus, and early Homo. Very low \u03b444/42Ca values (<\u22121.4\u2030), indicative of milk consumption, are measured in early Homo but not in A. africanus and P. robustus. In these latter taxa, transitional or adult nonmilk foods must have been provided in substantial quantities relative to breast milk rapidly after birth. The results suggest that early Homo have continued a predominantly breast milk\u2013based nursing period for longer than A. africanus and P. robustus and have consequently more prolonged interbirth interval.", "keyphrases": ["enamel", "nursing behavior", "hominin", "milk consumption"]}
{"id": "10.1080/02724634.1993.10011502", "title": "Indicators of locomotor habits in xenarthrans: Evidence for locomotor heterogeneity among fossil sloths", "abstract": "ABSTRACT A striking diversity in limb morphology among fossil sloths suggests that the traditional distinction between extant \u201ctree\u201d sloths and fossil \u201cground\u201d sloths merits closer scrutiny. Morphologically, xenarthrans (sloths, anteaters, and armadillos) are divergent from other mammalian orders. However, morphological shape indices of aspects of the elbow, hip, and knee joints that clearly discriminate locomotor modes in primates, carnivores, and bovids also succeed in differentiating the fully arboreal, semiarboreal, and terrestrial genera of anteaters. When compared to this extant data base, fossil sloths from both the Pleistocene radiation of the Antilles and the Santacrucian radiation of Argentina exhibit a range of values for these indices comparable to those of primates and anteaters. These results indicate that the diversity of limb structure in fossil sloths is associated with variation in posture and locomotor habits including arboreality, semiarboreality, and terrestriality.", "keyphrases": ["locomotor habit", "fossil sloth", "sloth", "index"]}
{"id": "paleo.006944", "title": "Complexity and diversity of eyes in Early Cambrian ecosystems", "abstract": "Here we report exceptionally preserved non-biomineralized compound eyes of a non-trilobite arthropod Cindarella eucalla from the lower Cambrian Chengjiang Lagersta \u00a8tte, China. The specimen represents the oldest microanatomical evidence confirming the occurrence of highly developed vision in the early Cambrian, over 2,000 ommatidia in each eye. Moreover, a quantitative analysis of the distribution of eyes related to life habit, feeding types, and phyla respectively, from the Chengjiang biota indicates that specimens with eyes mostly belong to the arthropods, and they usually were actively mobile epifaunal and nektonic forms as hunters or scavengers. Arthropods took the lead in evolution of 'good vision' and domination in Cambrian communities, which supports the hypothesis that the origin and evolution of 'good vision' was a key trait that promoted preferential diversification and formed the foundation of modern benthic ecosystems in the early Cambrian ocean.\nT he pervasiveness, intricacy, and complexity of animal eyes has long attracted the attention of scientists. The diverse types of extant eyes reflect the selective advantages of using light as a source of information throughout evolution 1 . It is largely accepted that proper vision originated in the early Cambrian during the initial radiation of many animal groups 2-4 , known as the Cambrian explosion [5] [6] [7] . The evolution of powerful vision has been proposed as a trigger for the Cambrian explosion of animals 8, 9 . However, the evolutionary origin and diversity of types of eyes still remains obscure. The record of early eyes is exceptionally sparse because most eyes are composed of soft tissue that does not usually fossilize, so much detail has been lost in mud and deep time. The availability of Cambrian Konservat-Lagersta \u00a8tten 5, 10, 11 with exceptional preservation offers the possibility to shed new light on the origin of eyes. The occurrence of eyes within the Chengjiang biota (approximately 520 million years ago) shows a remarkable variety of visual systems, which represent the earliest eyes in the metazoan fossil record [10] [11] [12] [13] [14] . More than 230 animal species have been described in the Chengjiang biota, representing at least 18 animal phyla and a variety of taxonomically enigmatic forms 15 , including primitive vertebrates 16 , which have great potential for understanding origination and evolution of visual systems in different animal phyla and their influence on the development of ecological communities in deep time. Here we report exceptionally preserved non-biomineralized eyes, preserved together with the body, of a non-trilobite arthropod Cindarella eucalla 10,17 from the early Cambrian Chengjiang biota, revealing the detailed structures of compound eyes. Together with a quantitative analysis of the distribution of eyes related to life habit, feeding types, and phyla, based on abundance data collected from a Chengjiang biota locality, we then explore the evolution of vision and its influence on ecological communities in the early Cambrian ocean.\nSpecimens of exceptionally preserved Cindarella eucalla with eyes as well as abundance data of the Chengjiang biota (86 species, 9941 individuals) were collected from a single quarry during study of a narrow stratigraphic interval from the lower Cambrian Maotianshan Shale in the Mafang section (N 24u469, E 102u359), Haikou, Yunnan Province, China, where one of the richest Chengjiang fossil deposits exists 18 . The fossils at the Mafang section feature an abundance and diversity of well-preserved soft-bodied animals that were subjected to limited or no pre-burial transportation and limited post-burial decay 18 . These fossils therefore present a record of the living soft-bodied animal community and provide unparalleled materials for understanding community paleoecology in the early Cambrian. In this abundance data analysis, we focus on the quantitative distribution of eyes and their relationship to phyla and ecological groups. For each taxon, its individual abundance and the presence/absence of macroscopic eye organs has been recorded (Supplementary Table 1 ).", "keyphrases": ["eye", "ecosystem", "chengjiang biota", "complexity"]}
{"id": "10.1080/02724634.1998.10011036", "title": "Systematic revision of the Protostegidae, with a redescription of Calcarichelys gemma Zangerl, 1953", "abstract": "ABSTRACT A revised classification is proposed for the Protostegidae. This revision is aided significantly by a redescription of Calcarichelys gemma Zangerl, 1953 based on a nearly complete specimen from the Mooreville Chalk (Campanian) of Alabama. The phylogenetic relationships of \u201cProtostega\u201d eaglefordensis are unresolved but it does not belong in the genus Protostega. Protostega dixie and Protostega potens are junior synonyms of Protostega gigas. Archelon copei is placed in a new genus, Microstega, and is included with Archelon ischyros, Calcarichelys gemma, Chelosphargis advena, and Protostega gigas in the family Protostegidae. The protostegids have the following synapomorphies: absence of the foramen palatinum posterius; a basioccipital with knob-like processes fitting into sockets on the posterior end of the pterygoids; the presence of only one suprapygal; and a T-shaped entoplastron that is not sutured to the other plastral elements. Evidence exists for a larger group containing Desmatochelys, Rhino...", "keyphrases": ["revision", "protostegidae", "calcarichelys gemma zangerl", "archelon ischyro"]}
{"id": "paleo.002388", "title": "Neogene sloth assemblages (Mammalia, Pilosa) of the Cocinetas Basin (La Guajira, Colombia): implications for the Great American Biotic Interchange", "abstract": "We describe sloth assemblages from the Cocinetas Basin (La Guajira peninsula, Colombia), found in the Neogene Castilletes and Ware formations, located in northernmost South America, documenting otherwise poorly known biotas. The tentative referral of a specimen to a small megatherioid sloth, Hyperleptus?, from the early\u2013middle Miocene Castilletes Formation, suggests affinities of this fauna with the distant Santa Cruz Formation and documents a large latitudinal distribution for this taxon. The late Pliocene Ware Formation is much more diverse, with five distinct taxa representing every family of \u2018ground sloths\u2019. This diversity is also remarkable at the ecological level, with sloths spanning over two orders of magnitude of body mass and probably having different feeding strategies. Being only a few hundred kilometres away from the Isthmus of Panama, and a few hundred thousand years older than the classically recognized first main pulse of the Great American Biotic interchange (GABI 1), the Ware Formation furthermore documents an important fauna for the understanding of this major event in Neogene palaeobiogeography. The sloths for which unambiguous affinities were recovered are not closely related to the early immigrants found in North America before GABI 1.", "keyphrases": ["sloth assemblage", "cocinetas basin", "american biotic interchange"]}
{"id": "10.1111/j.1096-3642.2010.00665.x", "title": "A phylogenetic analysis of Diplodocoidea (Saurischia: Sauropoda)", "abstract": "Diplodocoidea includes some of the first well-known sauropod dinosaurs, including such late 19th century and early 20th century discoveries as Apatosaurus, Diplodocus, and Dicraeosaurus. As a consequence of their long history of study, the basic set of suprageneric diplodocoid interrelationships is well resolved, and the diagnostic features of each genus are well established. However, intergeneric relationships are less resolved, including the relationships of putatively basal taxa like Amphicoelias and Haplocanthosaurus, the flagellicaudatan Suuwassea, and the highly specialized rebbachisaurids. For the rebbachisaurids, this uncertainty is coupled with a recent surge in the discovery of new taxa. Comparative cladistic methods demonstrate that character and taxon sampling need to be improved before greater phylogenetic resolution can be expected. Here, I present a new phylogenetic analysis that resolves many of the outstanding questions regarding the relationships within Diplodocoidea and examines palaeobiogeographical trends within the group. Suuwassea is recovered as a basal dicraeosaurid (the only Laurasian member of the group), and two distinct clades of rebbachisaurids are identified: a group closely allied with Nigersaurus and a clade associated with Limaysaurus. Amphicoelias, Amazonsaurus, and Haplocanthosaurus are provisionally placed as successively less-derived taxa at the base of Diplodocoidea. A North American origin for Diplodocoidea and Flagellicaudata is hypothesized based on the geographical and temporal distribution of those taxa. Rebbachisaurid taxa demonstrate a South American/African vicariance pattern, but the timing of the event pre-dates the proposed final rifting of those continents by c. 40 million years; the meaning of this discrepancy is uncertain. \n \n \n \n\u00a9 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161, 872\u2013915.", "keyphrases": ["phylogenetic analysis", "diplodocoidea", "suuwassea", "basal dicraeosaurid"]}
{"id": "10.1073/pnas.0812631106", "title": "Quantitative analysis of dental microwear in hadrosaurid dinosaurs, and the implications for hypotheses of jaw mechanics and feeding", "abstract": "Understanding the feeding mechanisms and diet of nonavian dinosaurs is fundamental to understanding the paleobiology of these taxa and their role in Mesozoic terrestrial ecosystems. Various methods, including biomechanical analysis and 3D computer modeling, have been used to generate detailed functional hypotheses, but in the absence of either direct observations of dinosaur feeding behavior, or close living functional analogues, testing these hypotheses is problematic. Microscopic scratches that form on teeth in vivo during feeding are known to record the relative motion of the tooth rows to each other during feeding and to capture evidence of tooth\u2013food interactions. Analysis of this dental microwear provides a powerful tool for testing hypotheses of jaw mechanics, diet, and trophic niche; yet, quantitative analysis of microwear in dinosaurs has not been attempted. Here, we show that analysis of tooth microwear orientation provides direct evidence for the relative motions of jaws during feeding in hadrosaurid ornithopods, the dominant terrestrial herbivores of the Late Cretaceous. Statistical testing demonstrates that Edmontosaurus teeth preserve 4 distinct sets of scratches in different orientations. In terms of jaw mechanics, these data indicate an isognathic, near-vertical posterodorsal power stroke during feeding; near-vertical jaw opening; and propalinal movements in near anterior and near posterior directions. Our analysis supports the presence of a pleurokinetic hinge, and the straightness and parallelism of scratches indicate a tightly controlled occlusion. The dominance of scratched microwear fabrics suggests that Edmontosaurus was a grazer rather than a browser.", "keyphrases": ["dental microwear", "hadrosaurid dinosaur", "jaw mechanic", "tooth", "powerful tool"]}
{"id": "paleo.008178", "title": "Experimental maturation of feathers: implications for reconstructions of fossil feather colour", "abstract": "Fossil feathers often preserve evidence of melanosomes\u2014micrometre-scale melanin-bearing organelles that have been used to infer original colours and patterns of the plumage of dinosaurs. Such reconstructions acknowledge that evidence from other colour-producing mechanisms is presently elusive and assume that melanosome geometry is not altered during fossilization. Here, we provide the first test of this assumption, using high pressure\u2013high temperature autoclave experiments on modern feathers to simulate the effects of burial on feather colour. Our experiments show that melanosomes are retained despite loss of visual evidence of colour and complete degradation of other colour-producing structures (e.g. quasi-ordered arrays in barbs and the keratin cortex in barbules). Significantly, however, melanosome geometry and spatial distribution are altered by the effects of pressure and temperature. These results demonstrate that reconstructions of original plumage coloration in fossils where preserved features of melanosomes are affected by diagenesis should be treated with caution. Reconstructions of fossil feather colour require assessment of the extent of preservation of various colour-producing mechanisms, and, critically, the extent of alteration of melanosome geometry.", "keyphrases": ["feather", "fossilization", "melanosome", "barb", "experimental maturation"]}
{"id": "10.1126/science.aaa3716", "title": "Evolutionary innovation and ecology in marine tetrapods from the Triassic to the Anthropocene", "abstract": "Similar shapes inhabit the sea Over biological history, several different groups of vertebrate tetrapods have reinvaded the marine environment. Although these groups are widely distributed among reptiles, mammals, amphibians, and birds, the shapes they have evolved are remarkably similar. Kelley and Pyenson review the literature on marine vertebrate groups over time and describe the innovations that facilitated the evolution of these marine forms, the environmental conditions that selected for such convergence of form, and the threats they face from future environment change. Science, this issue 10.1126/science.aaa3716 The demands of a marine environment induced similar adaptations across multiple invasions of different vertebrate groups. BACKGROUND More than 30 different lineages of amphibians, reptiles, birds, and mammals have independently invaded oceans ecosystems. Prominent examples include ichthyosaurs and mosasaurs during the Mesozoic (252 to 66 million years ago) and penguins and sea otters during the Cenozoic (66 million years ago to the present). In today\u2019s oceans, marine tetrapods are ecologically important consumers with trophic influence disproportionate to their abundance. They have occupied apex roles in ocean food webs for more than 250 million years, through major changes in ocean and climate, and through mass extinctions. Major paleontological discoveries in the past 40 years have clarified the early land-sea transitions for some marine tetrapods (e.g., whales, sea cows), although the terrestrial origins of many lineages remain obscure. Incipient invasions appear frequently in marine tetrapod history, but such early transitions account for only a small proportion of the total fossil record of successful marine lineages, which in some cases persist for hundreds of millions of years. ADVANCES Marine tetrapods provide ideal models for testing macroevolutionary hypotheses because the repeated transitions between land and sea have driven innovation, convergence, and diversification against a backdrop of changing marine ecosystems and mass extinctions. Recent investigations across a broad range of scales\u2014from molecules to food webs\u2014have clarified the phylogenetic scope, timing, and ecological consequences of these repeated innovations. Studies of the physiology and functional morphology of living species have illuminated the constraints and tradeoffs that shape the pathway of initial marine invasions. Comparative studies on muscle myoglobin concentration or the evolution of sex determination mechanisms, for example, have revealed rampant convergence for these adaptive traits in the marine realm. Exceptionally preserved fossils have also revealed insights into reproductive biology, soft tissue structures, and trophic interactions. Fossils provide critical baselines for understanding historical changes in marine communities and diversity through time, and these baselines remain vital for evaluating the ongoing and severe anthropogenic disturbance to marine tetrapod populations and marine ecosystems as a whole. OUTLOOK Technological advances in remote sensing and biologging will continue to provide crucial insights into the macroecology of marine tetrapods below the water\u2019s edge. Field data, when combined with extensive vouchers represented in museum collections, provide the basis for integrative models of the function and ecology of these logistically challenging organisms. Placed in a phylogenetic comparative framework, these data can enable tests of hypotheses about macroevolutionary patterns. Although perpetually incomplete, new fossil discoveries continue to improve our understanding of the early land-sea transitions in lineages and reveal past ecologies that could not have otherwise been predicted. Emerging imaging, molecular, and isotopic techniques provide an opportunity to expand the investigational scope for studying extinct taxa and to inform our understanding of how living species evolved. Lastly, resolving the full evolutionary scope of marine tetrapod history provides context for the origins of modern ecological patterns and interactions, which are fundamentally being altered by human activities. A unified view of marine tetrapod evolution. Circles mark initial invasions of marine tetrapod groups. Extinct and extant lineages are denoted by open and solid circles, respectively (yellow, amphibians; green, nonavian reptiles; blue, birds; red, mammals). Top curve summarizes marine tetrapod fossil richness through time. Schematic limb drawings demonstrate convergent hydrodynamic forelimbs in marine tetrapods (top to bottom): sea lion, whale, penguin, sea turtle, mosasaur, ichthyosaur. Ma, millions of years ago. Many top consumers in today\u2019s oceans are marine tetrapods, a collection of lineages independently derived from terrestrial ancestors. The fossil record illuminates their transitions from land to sea, yet these initial invasions account for a small proportion of their evolutionary history. We review the history of marine invasions that drove major changes in anatomy, physiology, and ecology over more than 250 million years. Many innovations evolved convergently in multiple clades, whereas others are unique to individual lineages. The evolutionary arcs of these ecologically important clades are framed against the backdrop of mass extinctions and regime shifts in ocean ecosystems. Past and present human disruptions to marine tetrapods, with cascading impacts on marine ecosystems, underscore the need to link macroecology with evolutionary change.", "keyphrases": ["ecology", "marine tetrapod", "tetrapod", "ocean", "mass extinction"]}
{"id": "10.2110/palo.2011.p11-019r", "title": "PALEOGENE EVOLUTION OF PRECIPITATION IN NORTHEASTERN CHINA SUPPORTING THE MIDDLE EOCENE INTENSIFICATION OF THE EAST ASIAN MONSOON", "abstract": "ABSTRACT The timing of the development of the East Asian monsoon in the geologic past is critically important for paleoclimatological studies, yet few quantitative data are available. Based on palynomorphs from six formations, supplemented by leaf fossils from one of these formations in Fushun, northeastern China, we present a quantitative estimate of the evolution of precipitation in this area during the middle Paleocene\u2013late Eocene. The results demonstrate that seasonal precipitation prevailed during the interval, suggesting that the monsoonal system had already developed by this time. Comparing Paleogene climatic results from different latitudes in eastern China, we conclude that the East Asian monsoon must have been significantly enhanced after the late middle Eocene (\u223c41\u201340 Ma), due to increased precipitation differentiation between wet and dry months as shown in the present study. The influence of both the uplift of the Da Hinggan Mountains in northeastern Asia on regional topography and the India-Asia collision globally may have contributed to early monsoon intensification by their influence on air mass movement and associated precipitation patterns in the monsoonal realm.", "keyphrases": ["precipitation", "northeastern china", "east asian monsoon", "monsoonal system"]}
{"id": "paleo.006643", "title": "Drowning, extinction, and subsequent facies development of the Devonian H\u00f6nne Valley Reef (northern Rhenish Massif, Germany)", "abstract": "The Hagen-Balve Reef is one of the largest Devonian carbonate complexes in the Rhenish Massif exposed in many former or active, economically significant quarries, especially in the H\u00f6nne Valley region at its eastern end. The timing and patterns of reef drowning, final extinction, and the middle Frasnian to middle Famennian post-reefal facies history, including details of the global Kellwasser Crisis, were studied based on two boreholes (HON_1101 and B102) and one outcrop at the Beul near Eisborn. More than 100 conodont samples provided a fine biostratigraphic framework and included new forms left in open nomenclature. The ca. upper 80 m of the new Asbeck Member of the Hagen-Balve Formation consists of relatively monotonous lagoonal successions assigned to four microfacies types. The local diversity of reef builders, mostly stromatoporoids, is low. Fenestral microbialites indicate very shallow and rather hostile back-reef settings. Near the Middle/Upper Devonian boundary, the eustatic pulses of the global Frasnes Events led to a significant backstepping of the reef margin, with reef core/outer slope facies overlying lagoonal facies. This flooding drastically reduced the carbonate accumulation rate and enabled the invasion of drowned back-reef areas by open-water organisms, such as polygnathid conodonts. Within this Eisborn Member, five microfacies types and numerous subtypes are distinguished including lowdiversity \"coral gardens\" and a final, top lower Frasnian parabiostrome dominated by tabulate and colonial rugose corals. There was no cap stage (\"Iberg Facies\"). Two phases of the Basal Frasnes Event are marked by dark, organic rich limestones with subordinate reef builders. Based on conodont fauna from overlying nodular limestones of the new, (hemi-)pelagic Beul Formation, the final H\u00f6nne Valley reef extinction was caused by the eustatic Middlesex Event at the lower/middle Frasnian boundary. Within the Beul Formation, eight subphotic submarine rise microfacies types are distinguished. After a lower middle Frasnian phase of extreme condensation, rich conodont faunas enable the recognition of most upper Frasnian to middle Famennian zones. The global semichatovae Event led to a regionally unique intercalation by four phases of organic-rich, laminated black shales and intervening thin limestones in core HON_1101. The Lower Kellwasser Event is represented in HON_1101 by atypical, moderately C org -rich, recrystallized, peloidal ostracod-mollusk pack-grainstones. The Upper Kellwasser level begins with an ostracod bloom, followed either by recrystallized mollusk wacke-packstones (HON_1101) or laminated, argillaceous mudstones (B102). The first indicates a rarely documented shallow subphotic, better oxygenated setting than typical Upper Kellwasser facies. As elsewhere, the top-Frasnian conodont extinction was severe. The lower/middle Famennian carbonate microfacies of the Beul Formation is relatively monotonous and typical for an oxic, pelagic submarine rise. The youngest recorded nodular limestones fall in the Palmatolepis marginifera utahensis Zone. Regionally uniform lydites of the Hardt Formation show that the local palaeotopography was levelled before the base of the This article is a contribution to the special issue \"The Rhenish Massif: More than 150 years of research in a Variscan mountain chain\" *", "keyphrases": ["reef", "rhenish massif", "hagen-balve reef complex", "ardennes shelf"]}
{"id": "10.1002/jmor.10029", "title": "Bone microstructure and developmental plasticity in birds and other dinosaurs", "abstract": "Patterns of bone microstructure have frequently been used to deduce dynamics and processes of growth in extant and fossil tetrapods. Often, the various types of primary bone tissue have been associated with different bone deposition rates and more recently such deductions have extended to patterns observed in dinosaur bone microstructure. These previous studies are challenged by the findings of the current research, which integrates an experimental neontological approach and a paleontological comparison. We use tetracycline labeling and morphometry to study the variability of bone deposition rates in Japanese quail (Coturnix japonica) growing under different experimental conditions. We compare resulting patterns in bone microstructure with those found in fossil birds and other dinosaurs. We found that a single type of primary bone varies significantly in rates of growth in response to environmental conditions. Ranging between 10\u201350 \u03bcm per day, rates of growth overlap with the full range of bone deposition rates that were previously associated with different patterns of bone histology. Bone formation rate was significantly affected by environmental/experimental conditions, skeletal element, and age. In the quail, the experimental conditions did not result in formation of lines of arrested growth (LAGs). Because of the observed variation of bone deposition rates in response to variation in environmental conditions, we conclude that bone deposition rates measured in extant birds cannot simply be extrapolated to their fossil relatives. Additionally, we observe the variable incidence of LAGs and annuli among several dinosaur species, including fossil birds, extant sauropsids, as well as nonmammalian synapsids, and some extant mammals. This suggests that the ancestral condition of the response of bone to environmental conditions was variable. We propose that such developmental plasticity in modern birds may be reduced in association with the shortened developmental time during the later evolution of the ornithurine birds. J. Morphol. 254:232\u2013246, 2002. \u00a9 2002 Wiley\u2010Liss, Inc.", "keyphrases": ["plasticity", "other dinosaur", "bone microstructure", "blood vessel"]}
{"id": "10.1111/ele.12203", "title": "The ecological consequences of megafaunal loss: giant tortoises and wetland biodiversity", "abstract": "The giant tortoises of the Gal\u00e1pagos have become greatly depleted since European discovery of the islands in the 16th Century, with populations declining from an estimated 250 000 to between 8000 and 14 000 in the 1970s. Successful tortoise conservation efforts have focused on species recovery, but ecosystem conservation and restoration requires a better understanding of the wider ecological consequences of this drastic reduction in the archipelago's only large native herbivore. We report the first evidence from palaeoecological records of coprophilous fungal spores of the formerly more extensive geographical range of giant tortoises in the highlands of Santa Cruz Island. Upland tortoise populations on Santa Cruz declined 500\u2013700 years ago, likely the result of human impact or possible climatic change. Former freshwater wetlands, a now limited habitat-type, were found to have converted to Sphagnum bogs concomitant with tortoise loss, subsequently leading to the decline of several now-rare or extinct plant species.", "keyphrases": ["ecological consequence", "giant tortoise", "decline"]}
{"id": "10.1111/jzo.12110", "title": "Interpreting ecology and behaviour from the vertebrate fossil track record", "abstract": "Fossil tracks represent a direct window onto the lives of extinct organisms, being formed and preserved in situ. Because track morphology is determined by limb motion, foot anatomy and substrate consistency, studies of fossil tracks can provide insight into producer, behaviour and palaeoenvironment. However, each determining factor is subject to variation, either continuous or discrete, and this variation may be co-dependent, making it difficult to correctly interpret a track. In addition to variance from the track-forming variables, tracks and tracksites are subject to further obfuscation because of time averaging, even before the effects of weathering, erosion and exposure are accounted for. This paper presents a discussion of the factors that may confound interpretation of fossil tracks, trackways and tracksites, and reviews experimental studies that have attempted to elucidate and eliminate these sources of confusion.", "keyphrases": ["behaviour", "track morphology", "foot", "substrate property"]}
{"id": "paleo.000778", "title": "Discovery of bilaterian-type through-guts in cloudinomorphs from the terminal Ediacaran Period", "abstract": "The fossil record of the terminal Ediacaran Period is typified by the iconic index fossil Cloudina and its relatives. These tube-dwellers are presumed to be primitive metazoans, but resolving their phylogenetic identity has remained a point of contention. The root of the problem is a lack of diagnostic features; that is, phylogenetic interpretations have largely centered on the only available source of information\u2014their external tubes. Here, using tomographic analyses of fossils from the Wood Canyon Formation (Nevada, USA), we report evidence of recognizable soft tissues within their external tubes. Although alternative interpretations are plausible, these internal cylindrical structures may be most appropriately interpreted as digestive tracts, which would be, to date, the earliest-known occurrence of such features in the fossil record. If this interpretation is correct, their nature as one-way through-guts not only provides evidence for establishing these fossils as definitive bilaterians but also has implications for the long-debated phylogenetic position of the broader cloudinomorphs.", "keyphrases": ["cloudinomorph", "terminal ediacaran period", "relative"]}
{"id": "10.1146/annurev-earth-082517-010009", "title": "The Origin and Evolutionary Biology of Pinnipeds: Seals, Sea Lions, and Walruses", "abstract": "The oldest definitive pinniped fossils date from approximately 30.6\u201323 million years ago (Ma) in the North Pacific. Pinniped monophyly is consistently supported; the group shares a common ancestry with arctoid carnivorans, either ursids or musteloids. Crown pinnipeds comprise the Otariidae (fur seals and sea lions), Odobenidae (walruses), and Phocidae (seals), with paraphyletic \u201cenaliarctines\u201d falling outside the crown group. The position of extinct Desmatophocidae is debated; they are considered to be closely related to both otariids and odobenids or, alternatively, to phocids. Both otariids and odobenids are known from the North Pacific, diverging approximately 19 Ma, with phocids originating in the North Atlantic or Paratethys region 19\u201314 Ma. Our understanding of pinniped paleobiology has been enriched by studies that incorporate anatomical and behavioral data into a phylogenetic framework. There is now evidence for sexual dimorphism in the earliest pinnipeds, heralding polygynous breeding systems, followed by increased body sizes, diving capabilities, and diverse feeding strategies in later-diverging phocid and otarioid lineages.", "keyphrases": ["seal", "sea lion", "north pacific", "otariidae", "body size"]}
{"id": "paleo.000669", "title": "Quantifying the dark data in museum fossil collections as palaeontology undergoes a second digital revolution", "abstract": "Large-scale analysis of the fossil record requires aggregation of palaeontological data from individual fossil localities. Prior to computers, these synoptic datasets were compiled by hand, a laborious undertaking that took years of effort and forced palaeontologists to make difficult choices about what types of data to tabulate. The advent of desktop computers ushered in palaeontology's first digital revolution\u2014online literature-based databases, such as the Paleobiology Database (PBDB). However, the published literature represents only a small proportion of the palaeontological data housed in museum collections. Although this issue has long been appreciated, the magnitude, and thus potential significance, of these so-called \u2018dark data\u2019 has been difficult to determine. Here, in the early phases of a second digital revolution in palaeontology\u2014the digitization of museum collections\u2014we provide an estimate of the magnitude of palaeontology's dark data. Digitization of our nine institutions' holdings of Cenozoic marine invertebrate collections from California, Oregon and Washington in the USA reveals that they represent 23 times the number of unique localities than are currently available in the PBDB. These data, and the vast quantity of similarly untapped dark data in other museum collections, will, when digitally mobilized, enhance palaeontologists\u2019 ability to make inferences about the patterns and processes of past evolutionary and ecological changes.", "keyphrases": ["dark data", "palaeontology", "digital revolution", "digitization"]}
{"id": "10.1073/pnas.0704088104", "title": "The relative importance of directional change, random walks, and stasis in the evolution of fossil lineages", "abstract": "The nature of evolutionary changes recorded by the fossil record has long been controversial, with particular disagreement concerning the relative frequency of gradual change versus stasis within lineages. Here, I present a large-scale, statistical survey of evolutionary mode in fossil lineages. Over 250 sequences of evolving traits were fit by using maximum likelihood to three evolutionary models: directional change, random walk, and stasis. Evolution in these traits was rarely directional; in only 5% of fossil sequences was directional evolution the most strongly supported of the three modes of change. The remaining 95% of sequences were divided nearly equally between random walks and stasis. Variables related to body size were significantly less likely than shape traits to experience stasis. This finding is in accord with previous suggestions that size may be more evolutionarily labile than shape and is consistent with some but not all of the mechanisms proposed to explain evolutionary stasis. In general, similar evolutionary patterns are observed across other variables, such as clade membership and temporal resolution, but there is some evidence that directional change in planktonic organisms is more frequent than in benthic organisms. The rarity with which directional evolution was observed in this study corroborates a key claim of punctuated equilibria and suggests that truly directional evolution is infrequent or, perhaps more importantly, of short enough duration so as to rarely register in paleontological sampling.", "keyphrases": ["directional change", "stasis", "fossil lineage", "maximum likelihood", "body size"]}
{"id": "paleo.002600", "title": "Beyond Coprinisphaera: fossil nests of dung beetles", "abstract": "Forty-two remains of fossil nests of dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae), which were recorded in four formations of the Cenozoic of South America, are described herein for the first time. Most of them are represented by nesting chambers containing a fossil brood ball (Coprinisphaera). However, in the most remarkable cases, parts of the burrows constructed by the parents and/ or the vertical emergence burrows constructed by the offspring are preserved too. The preservation of the dung beetle nests is very unusual but more recurrent in younger formations probably because of the short-term action of the diagenetic processes. Considering that the construction of brood balls always involves the construction of nests, the ichnotaxonomical proposal is that the remains of fossil nests should be considered as 'structures associated with Coprinisphaera' and added to the diagnosis to avoid the proliferation of names. The study of the fossil nests provides new palaeoetological inferences for dung beetles, such as the Nesting Pattern of the trace makers of Coprinisphaera tonnii and Coprinisphaera akatanka, and how phylogenetically related were they with the extant necrophagous species of the genera Coprophanaeus and Canthon, respectively. Additionally, the fossil evidence suggests that simple nests of dung beetles predate compound nests. \u25a1 Fossil brood balls, nesting behaviour, nesting chambers, Scarabaeinae, trace fossils.", "keyphrases": ["coprinisphaera", "fossil nest", "dung beetle", "brood ball", "extant necrophagous specie"]}
{"id": "paleo.012421", "title": "Neanderthal Extinction by Competitive Exclusion", "abstract": "Background Despite a long history of investigation, considerable debate revolves around whether Neanderthals became extinct because of climate change or competition with anatomically modern humans (AMH). Methodology/Principal Findings We apply a new methodology integrating archaeological and chronological data with high-resolution paleoclimatic simulations to define eco-cultural niches associated with Neanderthal and AMH adaptive systems during alternating cold and mild phases of Marine Isotope Stage 3. Our results indicate that Neanderthals and AMH exploited similar niches, and may have continued to do so in the absence of contact. Conclusions/Significance The southerly contraction of Neanderthal range in southwestern Europe during Greenland Interstadial 8 was not due to climate change or a change in adaptation, but rather concurrent AMH geographic expansion appears to have produced competition that led to Neanderthal extinction.", "keyphrases": ["climate change", "europe", "neanderthal extinction", "cause"]}
{"id": "10.1080/02724634.1993.10011486", "title": "Studies on Skeleton formation in reptiles. IV. The homology of the reptilian (amniote) astragalus revisited", "abstract": "ABSTRACT In extant turtles and lepidosaurs, the astragalus forms from a single ossification center in a tarsale proximale resulting from fusion of originally separate chondrogenic condensations in the proximal tarsus. In crocodiles, the astragalus also ossifies from a single center although the cartilaginous precursors of astragalus and calcaneum do not fuse to form a tarsale proximale. Developmental stages of the parareptilian Mesosaurus document a similar ossification pattern, as do ontogenic series of a number of fossil diapsid reptiles. There is no consistent evidence of ontogenetic fusion of a \u201ctibiale,\u201d intermedium, and centrale to form the astragalus of Captorhinus. The development of the amniote astragalus contrasts with variable patterns of fusion of originally separate proximal tarsal ossifications in anthracosaurian amphibians and in Diadectes. It is concluded that the reptilian (and probably also the mammalian) astragalus is a neomorph, which resulted from ontogenetic repatterning and is diagn...", "keyphrases": ["homology", "astragalus", "centrale"]}
{"id": "paleo.001294", "title": "First evidence of azhdarchid pterosaurs from the Late Cretaceous of Hungary", "abstract": "New remains of an azhdarchid pterosaur were discovered from the Upper Cretaceous (Santonian) Csehb\u00e1nya Formation at the Ihark\u00fat vertebrate locality in the Bakony Mountains, western Hungary. Among the isolated bones, consisting principally of 21 symphyseal jaw fragments, four cervical vertebrae, a right radius, and some fragmentary limb bones, is a complete articulated mandible that represents one of the best-preserved mandibular material of any presently known azhdarchid pterosaur. The complete edentulous jaw, referred to Bakonydraco galaczi gen. et sp. nov. posesses several features diagnostic for azhdarchids which prove that Bakonydraco belongs to this group. The cervical vertebrae exhibit azhdarchid features and consequently are referred to as Azhdarchidae indet. The discovery of these fossils helps to understand the construction of the azhdarchid mandible and provides new insight for studying the feeding style of the edentulous azhdarchid pterosaurs.", "keyphrases": ["azhdarchid pterosaur", "santonian", "bakonydraco"]}
{"id": "10.1126/science.aaf3161", "title": "Genomic and archaeological evidence suggest a dual origin of domestic dogs", "abstract": "A dogged investigation of domestication The history of how wolves became our pampered pooches of today has remained controversial. Frantz et al. describe high-coverage sequencing of the genome of an Irish dog from the Bronze Age as well as ancient dog mitochondrial DNA sequences. Comparing ancient dogs to a modern worldwide panel of dogs shows an old, deep split between East Asian and Western Eurasian dogs. Thus, dogs were domesticated from two separate wolf populations on either side of the Old World. Science, this issue p. 1228 Dogs may have been domesticated independently in Eastern and Western Eurasia from distinct wolf populations. The geographic and temporal origins of dogs remain controversial. We generated genetic sequences from 59 ancient dogs and a complete (28x) genome of a late Neolithic dog (dated to ~4800 calendar years before the present) from Ireland. Our analyses revealed a deep split separating modern East Asian and Western Eurasian dogs. Surprisingly, the date of this divergence (~14,000 to 6400 years ago) occurs commensurate with, or several millennia after, the first appearance of dogs in Europe and East Asia. Additional analyses of ancient and modern mitochondrial DNA revealed a sharp discontinuity in haplotype frequencies in Europe. Combined, these results suggest that dogs may have been domesticated independently in Eastern and Western Eurasia from distinct wolf populations. East Eurasian dogs were then possibly transported to Europe with people, where they partially replaced European Paleolithic dogs.", "keyphrases": ["domestication", "dog", "europe"]}
{"id": "paleo.010591", "title": "Flowering after disaster: Early Danian buckthorn (Rhamnaceae) flowers and leaves from Patagonia", "abstract": "Southern-Hemisphere terrestrial communities from the early Paleocene are poorly known, but recent work on Danian plant fossils from the Salamanca Formation in Chubut Province, Argentina are providing critical data on earliest Paleocene floras. The fossils described here come from a site in the Salamanca Formation dating to ca. 1 million years or less after the end-Cretaceous extinction event; they are the first fossil flowers reported from the Danian of South America, and possible the entire Southern Hemisphere. They are compressions and impressions in flat-laminated light gray shale, and they belong to the family Rhamnaceae (buckthorns). Flowers of Notiantha grandensis gen. et sp. nov. are pentamerous, with distinctly keeled calyx lobes projecting from the hypanthium, clawed and cucullate emarginate petals, antepetalous stamens, and a pentagonal floral disk that fills the hypanthium. Their phylogenetic position was evaluated using a molecular scaffold approach combined with morphological data. Results indicate that the flowers are most like those of extant ziziphoid Rhamnaceae. The associated leaves, assigned to Suessenia grandensis gen. et sp. nov. are simple and ovate, with serrate margins and three acrodromous basal veins. They conform to the distinctive leaves of some extant Rhamnaceae in the ziziphoid and ampelozizyphoid clades. These fossils provide the first unequivocal megafossil evidence of Rhamnaceae in the Southern Hemisphere, demonstrating that Rhamnaceae expanded beyond the tropics by the earliest Paleocene. Given previous reports of rhamnaceous pollen in the late Paleogene and Neogene of Antarctica and southern Australia, this new occurrence increases the possibility of high-latitude dispersal of this family between South America and Australia via Antarctica during the Cenozoic.", "keyphrases": ["buckthorn", "rhamnaceae", "salamanca formation", "flower"]}
{"id": "10.1080/03115518.2017.1397428", "title": "A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods", "abstract": "Kear, B.P., Fordyce, R.E., Hiller, N. & Siversson, M., December 2017. A palaeobiogeographical synthesis of Australasian Mesozoic marine tetrapods. Alcheringa 42, 461-486. ISSN 0311-5518. THE LAST 15 years has witnessed a blossoming of research on Australasian Mesozoic marine tetrapod fossils. Much of this work has focused on amniotes, particularly those from the prolific Lower Cretaceous (Aptian\u2013Albian) Lagerst\u00e4tten of the Eromanga Basin in central and eastern Australia, and Upper Cretaceous (Campanian\u2013Maastrichtian) sequences of the North and South islands of New Zealand. However, rare and less popularized remains have also been found in Lower Triassic\u2013mid-Cretaceous rocks from Australia, New Zealand and the Chatham Islands, and on the tectonically proximal landmasses of New Caledonia and Timor. Currently identified taxa include estuarine\u2013paralic rhytidostean, brachyopid, capitosaurian and trematosaurian temnospondyls from the earliest Triassic (Induan\u2013Olenekian), Middle\u2013Late Triassic (Anisian\u2013Norian) eosauropterygians, and mixosaurian, shastasaurian and euichthyosaurian ichthyosaurians, Early\u2013Middle Jurassic (Sinemurian\u2013Bajocian) ichthyosaurians, together with plesiosauroid and rhomaleosaurid-like plesiosaurians, and diverse Early (Aptian\u2013Albian) through to Late Cretaceous (Campanian\u2013Maastrichtian) elasmosaurid, leptocleidid, polycotylid, probable cryptoclidid and pliosaurid plesiosaurians, as well as ophthalmosaurid ichthyosaurians, sea turtles incorporating protostegids, and mosasaurid squamates. This faunal succession evidences almost continuous occupation of southern high-palaeolatitude seas, and repeated endemic diversifications (including nascent members of some key lineages) amongst emigrant cosmopolitan clades. The primary dispersal routes are likely to have been peri-Gondwanan, with coastal migrations along the western Tethys and polar margins of the Panthalassan Ocean. However, augmentation by increasing continental fragmentation and seaway corridor connectivity probably occurred from the Middle Jurassic to Late Cretaceous. Latest Cretaceous mosasaurid and elasmosaurid taxa also reveal regional affinities with the emergent western Pacific and Weddellian austral bioprovinces. The extreme rarity, or complete absence, of many major groups prevalent elsewhere in Gondwana (e.g., tanystropheids, Triassic sauropterygians, bothremydid marine turtles, thalattosuchians and dyrosaurid crocodylomorphs) is conspicuous, and might be related to stratigraphical/collecting biases, or the predominantly higher-palaeolatitude, cooler-water Mesozoic palaeogeography of the Australasian region. Although the burgeoning record is substantial, much still awaits discovery and adequate documentation; thus Australasia is still one of the most exciting prospects for future insights into the global history of Mesozoic marine tetrapods. Benjamin P. Kear* [benjamin.kear@em.uu.se] Museum of Evolution, Uppsala University, Norbyv\u00e4gen 16, SE-752 36 Uppsala, Sweden; R. Ewan Fordyce [ewan.fordyce@otago.ac.nz] Department of Geology, University of Otago, Post Box 56, Dunedin 9054, New Zealand; Norton Hiller [norton.hiller@gmail.com] Canterbury Museum, Rolleston Avenue, Christchurch 8013, New Zealand; Mikael Siversson [mikael.siversson@museum.wa.gov.au] Western Australian Museum, 49 Kew Street, Welshpool, Western Australia 6106.", "keyphrases": ["palaeobiogeographical synthesis", "australasian mesozoic", "marine tetrapod"]}
{"id": "paleo.006006", "title": "Tarsal morphology of the pleuraspidotheriid mammal Hilalia from the middle Eocene of Turkey", "abstract": "Pleuraspidotheriids are a group of primitive ungulate mammals that, until recently, were thought to be restricted to the late Paleocene of Western Europe. It has been hypothesized that this family actually survived in Central Anatolia until at least the middle Eocene. However, these anachronistically young Anatolian \u201csurvivors\u201d, including the genus Hilalia, were previously documented mainly by dental remains. Here, we describe the previously unknown astragalus of Hilalia saribeya, which confirms the pleuraspidotheriid affinities of the genus, and supports phylogenetic reconstructions that place Hilalia as the sister group of Pleuraspidotherium. The morphology of the astragalus suggests sub-cursorial plantigrade locomotion for H. saribeya, although its tarsal morphology remains generalized enough that scansorial capabilities cannot be ruled out. The evolution of Hilalia is addressed in the context of the apparent geographic isolation of Central Anatolia during the Eocene. The endemic character of the mammalian fauna of Central Anatolia during the middle Eocene emphasizes how the complex paleogeography of the northern margin of Neotethys impacted local biotas in a region situated at the crossroads of very distinctive biogeographic zones.", "keyphrases": ["pleuraspidotheriid", "hilalia", "late paleocene", "tarsal morphology"]}
{"id": "10.1002/spp2.1311", "title": "The ichnogenus Lumbricaria M\u00fcnster from the Upper Jurassic of Germany interpreted as faecal strings of ammonites", "abstract": "The trace fossil Lumbricaria M\u00fcnster is a common constituent of the Upper Jurassic lithographic limestones in southern Germany. Despite having been recognized more than 300 years ago, its nature and producer remain enigmatic. Controversial interpretations of Lumbricaria regard it either as the remains of worms, or as cololites (i.e. faecal material preserved in the gut) or coprolites (i.e. ejected faecal material) of worms, fish, holothurians or cephalopods. A morphological analysis of the type material and numerous specimens reveals two basic morphotypes of Lumbricaria, conformable with the ichnospecies L. intestinum (loosely confined, intertwined to elongate) and L. colon (well confined, densely entangled). Transitions and combinations between both ichnospecies exist and are the result of taphonomic effects. A comparison with modern analogues favours cephalopods (in particular nautiloids or ammonites) as the most likely producers of Lumbricaria, an interpretation that is supported by the finding of an Upper Jurassic nautiloid cast preserving a Lumbricaria\u2010like faecal string within its body chamber. Ammonites are the likely producers of Lumbricaria from the Upper Jurassic of Germany.", "keyphrases": ["upper jurassic", "faecal string", "ammonites"]}
{"id": "10.1126/science.1195550", "title": "Early Use of Pressure Flaking on Lithic Artifacts at Blombos Cave, South Africa", "abstract": "Ancient Innovations Pressure flaking is a method of forming points, grooves, and notches on stone tools in which a tool is pressed up against another stone, instead of striking it. It has been thought to be a fairly recent innovation, arising in the Upper Paleolithic 20,000 or so years ago. Mourre et al. (p. 659), show that tools from Blombos Cave, dating to about 75,000 years ago, have grooves and patterns resembling production by heat treatment followed by pressure flaking. Replication experiments were performed using similar source material followed by microscopic study of the tools. Despite the evidence for an early innovation, it seems that pressure flaking was not used widely elsewhere until much later; thus, such early innovations may have been sporadic ephemeral. Tools dating to ~75,000 years ago show evidence of pressure flaking, long before the technique became widespread. Pressure flaking has been considered to be an Upper Paleolithic innovation dating to ~20,000 years ago (20 ka). Replication experiments show that pressure flaking best explains the morphology of lithic artifacts recovered from the ~75-ka Middle Stone Age levels at Blombos Cave, South Africa. The technique was used during the final shaping of Still Bay bifacial points made on heat\u2010treated silcrete. Application of this innovative technique allowed for a high degree of control during the detachment of individual flakes, resulting in thinner, narrower, and sharper tips on bifacial points. This technology may have been first invented and used sporadically in Africa before its later widespread adoption.", "keyphrases": ["pressure flaking", "lithic artifact", "blombos cave", "point"]}
{"id": "paleo.011491", "title": "An Early Instance of Upper Palaeolithic Personal Ornamentation from China: The Freshwater Shell Bead from Shuidonggou 2", "abstract": "We report the discovery and present a detailed analysis of a freshwater bivalve from Shuidonggou Locality 2, layer CL3. This layer is located c. 40 cm below layer CL2, which has yielded numerous ostrich eggshell beads. The shell is identified as the valve of a Corbicula fluminea. Data on the occurrence of this species in the Shuidonggou region during Marine Isotope Stage 3 and taphonomic analysis, conducted in the framework of this study, of a modern biocoenosis and thanatocoenosis suggest that the archeological specimen was collected at one of the numerous fossil or sub-fossil outcrops where valves of this species were available at the time of occupation of level CL3. Experimental grinding and microscopic analysis of modern shells of the same species indicate that the Shuidonggou shell was most probably ground on coarse sandstone to open a hole on its umbo, attach a thread, and use the valve as a personal ornament. Experimental engraving of freshwater shells and microscopic analysis identify an incision crossing the archaeological valve outer surface as possible deliberate engraving. Reappraisal of the site chronology in the light of available radiocarbon evidence suggests an age of at least 34\u201333 cal kyr BP for layer CL3. Such estimate makes the C. fluminea recovered from CL3 one of the earliest instances of personal ornamentation and the earliest example of a shell bead from China.", "keyphrases": ["early instance", "china", "bead"]}
{"id": "10.1051/0004-6361/201116836", "title": "La2010: a new orbital solution for the long-term motion of the Earth", "abstract": "We present here a new solution for the astronomical computation of the orbital motion of the Earth spanning from 0 to \u2212250 Myr. The main improvement with respect to our previous numerical solution La2004 is an improved adjustment of the parameters and initial conditions through a fit over 1 Myr to a special version of the highly accurate numerical ephemeris INPOP08 (Integration Numerique Planetaire de l'Observatoire de Paris). The precession equations have also been entirely revised and are no longer averaged over the orbital motion of the Earth and Moon. This new orbital solution is now valid over more than 50 Myr in the past or into the future with proper phases of the eccentricity variations. Owing to the chaotic behavior, the precision of the solution decreases rapidly beyond this time span, and we discuss the behavior of various solutions beyond 50 Myr. For paleoclimate calibrations, we provide several different solutions that are all compatible with the most precise planetary ephemeris. We have thus reached the time where geological data are now required to discriminate between planetary orbital solutions beyond 50 Myr.", "keyphrases": ["new orbital solution", "solution", "motion", "past"]}
{"id": "paleo.009456", "title": "The Ladder of Life Detection", "abstract": "Abstract We describe the history and features of the Ladder of Life Detection, a tool intended to guide the design of investigations to detect microbial life within the practical constraints of robotic space missions. To build the Ladder, we have drawn from lessons learned from previous attempts at detecting life and derived criteria for a measurement (or suite of measurements) to constitute convincing evidence for indigenous life. We summarize features of life as we know it, how specific they are to life, and how they can be measured, and sort these features in a general sense based on their likelihood of indicating life. Because indigenous life is the hypothesis of last resort in interpreting life-detection measurements, we propose a small but expandable set of decision rules determining whether the abiotic hypothesis is disproved. In light of these rules, we evaluate past and upcoming attempts at life detection. The Ladder of Life Detection is not intended to endorse specific biosignatures or instruments for life-detection measurements, and is by no means a definitive, final product. It is intended as a starting point to stimulate discussion, debate, and further research on the characteristics of life, what constitutes a biosignature, and the means to measure them.", "keyphrases": ["ladder", "life detection", "biosignature"]}
{"id": "paleo.011318", "title": "Old African fossils provide new evidence for the origin of the American crocodiles", "abstract": "Molecular and morphological phylogenies concur in indicating that the African lineages formerly referred to Crocodylus niloticus are the sister taxon the four Neotropical crocodiles (Crocodylus intermedius, C. moreleti, C. acutus and C. rhombifer), implying a transoceanic dispersal from Africa to America. So far the fossil record did not contribute to identify a possible African forerunner of the Neotropical species but, curiously, the oldest remains referred to the African C. niloticus are Quaternary in age, whereas the oldest American fossils of Crocodylus are older, being dated to the early Pliocene, suggesting that another species could be involved. We re-described, also thanks to CT imaging, the only well-preserved topotipic skull of Crocodylus checchiai Maccagno, 1947 from the late Miocene (Messinian) African site of As Sahabi in Libya. As previously suggested on the basis of late Miocene material from Tanzania, C. checchiai is a valid, diagnosable species. According to our phylogenetic analyses, C. checchiai is related to the Neotropical taxa and could be even located at the base of their radiation, therefore representing the missing link between the African and the American lineages.", "keyphrases": ["crocodile", "late miocene", "libya"]}
{"id": "paleo.005229", "title": "X-ray microscopy reveals endophallic structures in a new species of the ground beetle genus Trechus Clairville, 1806 from Baltic amber (Coleoptera, Carabidae, Trechini)", "abstract": "Abstract The third fossil species of the genus Trechus Clairville, 1806 is described from Baltic amber: Trechus exhibitorius sp. n. Details of external and internal morphology were analysed using X-ray micro-computed tomography (micro-CT) and important diagnostic features of the internal male genital sac (endophallus) are described in detail for the first time in a fossil ground beetle. Based on these data, we could assign Trechus exhibitorius sp. n. to Trechus sensu stricto and this new fossil species seems to represent a basal branch of a lineage comprising species diverse groups of extant Trechus mainly distributed in the Caucasus and Anatolia. Thus, our results support previous studies suggesting that Trechus is a phylogenetically old lineage already present in the Eocene with numerous species.", "keyphrases": ["baltic amber", "tomography", "x-ray"]}
{"id": "paleo.002523", "title": "The Miocene: The Future of the Past", "abstract": "The Miocene epoch (23.03\u20135.33 Ma) was a time interval of global warmth, relative to today. Continental configurations and mountain topography transitioned toward modern conditions, and many flora and fauna evolved into the same taxa that exist today. Miocene climate was dynamic: long periods of early and late glaciation bracketed a \u223c2 Myr greenhouse interval\u2014the Miocene Climatic Optimum (MCO). Floras, faunas, ice sheets, precipitation, pCO2, and ocean and atmospheric circulation mostly (but not ubiquitously) covaried with these large changes in climate. With higher temperatures and moderately higher pCO2 (\u223c400\u2013600 ppm), the MCO has been suggested as a particularly appropriate analog for future climate scenarios, and for assessing the predictive accuracy of numerical climate models\u2014the same models that are used to simulate future climate. Yet, Miocene conditions have proved difficult to reconcile with models. This implies either missing positive feedbacks in the models, a lack of knowledge of past climate forcings, or the need for re\u2010interpretation of proxies, which might mitigate the model\u2010data discrepancy. Our understanding of Miocene climatic, biogeochemical, and oceanic changes on broad spatial and temporal scales is still developing. New records documenting the physical, chemical, and biotic aspects of the Earth system are emerging, and together provide a more comprehensive understanding of this important time interval. Here, we review the state\u2010of\u2010the\u2010art in Miocene climate, ocean circulation, biogeochemical cycling, ice sheet dynamics, and biotic adaptation research as inferred through proxy observations and modeling studies.", "keyphrases": ["miocene", "warmth", "flora", "future climate scenario", "concentration"]}
{"id": "10.1666/06054.1", "title": "Using a theoretical ecospace to quantify the ecological diversity of Paleozoic and modern marine biotas", "abstract": "Abstract The process of evolution hinders our ability to make large-scale ecological comparisons\u2014such as those encompassing marine biotas spanning the Phanerozoic\u2014because the compared entities are taxonomically and morphologically dissimilar. One solution is to focus instead on life habits, which are repeatedly discovered by taxa because of convergence. Such an approach is applied to a comparison of the ecological diversity of Paleozoic (Cambrian\u2013Devonian) and modern marine biotas from deep-subtidal, soft-substrate habitats. Ecological diversity (richness and disparity) is operationalized by using a standardized ecospace framework that can be applied equally to extant and extinct organisms and is logically independent of taxonomy. Because individual states in the framework are chosen a priori and not customized for particular taxa, the framework fulfills the requirements of a universal theoretical ecospace. Unique ecological life habits can be recognized as each discrete, n-dimensional combination of character states in the framework. Although the basic unit of analysis remains the organism, the framework can be applied to other entities\u2014species, clades, or multispecies assemblages\u2014for the study of comparative paleoecology and ecology. Because the framework is quantifiable, it is amenable to analytical techniques used for morphological disparity. Using these methods, I demonstrate that the composite Paleozoic biota is approximately as rich in life habits as the sampled modern biota, but that the life habits in the modern biota are significantly more disparate than those in the Paleozoic; these results are robust to taphonomic standardization. Despite broadly similar distributions of life habits revealed by multivariate ordination, the modern biota is composed of life habits that are significantly enriched, among others, in mobility, infaunality, carnivory, and exploitation of other organisms (or structures) for occupation of microhabitats.", "keyphrases": ["ecological diversity", "paleozoic", "modern marine biota"]}
{"id": "paleo.009956", "title": "Structure and function of a compound eye, more than half a billion years old", "abstract": "Significance An exceptionally well-preserved arthropod fossil from near the base of the lower Cambrian shows the internal sensory structures of a compound eye, more than half a billion years old. The trilobite to which it belongs is found in a zone where the first complete organisms appear in the fossil record; thus, it is probably the oldest record of a visual system that ever will be available. This compound eye proved to possess the same kind of structure as the eyes of bees and dragonflies living today, but it lacks the lenses that are typical of modern eyes of this type. There is an elegant physical solution, however, of how to develop a quality image of modern type. Until now, the fossil record has not been capable of revealing any details of the mechanisms of complex vision at the beginning of metazoan evolution. Here, we describe functional units, at a cellular level, of a compound eye from the base of the Cambrian, more than half a billion years old. Remains of early Cambrian arthropods showed the external lattices of enormous compound eyes, but not the internal structures or anything about how those compound eyes may have functioned. In a phosphatized trilobite eye from the lower Cambrian of the Baltic, we found lithified remnants of cellular systems, typical of a modern focal apposition eye, similar to those of a bee or dragonfly. This shows that sophisticated eyes already existed at the beginning of the fossil record of higher organisms, while the differences between the ancient system and the internal structures of a modern apposition compound eye open important insights into the evolution of vision.", "keyphrases": ["compound eye", "arthropod", "trilobite", "vision"]}
{"id": "10.1017/S0094837300007533", "title": "Estimating taxonomic diversity, extinction rates, and speciation rates from fossil data using capture-recapture models", "abstract": "Methods currently used to estimate taxonomic extinction probabilities from fossil data generally assume that the probability of encountering a specimen in a particular stratum, given that the taxon was extant in the time period and location represented by the stratum, either equals 1.0 or else is a constant for all strata. Methods used to estimate taxonomic diversity (number of taxa) and speciation rate generally assume that encounter probabilities equal 1.0. We suspect that these assumptions are often false. Capture-recapture models were historically developed for estimation in the face of variable and unknown sampling probabilities. These models can thus be used to estimate parameters of interest from paleobiological data when encounter probabilities are unknown and variable over time. These models also permit estimation of sampling variances, and goodness-of-fit tests are available for assessing the fit of data to most models. Here we describe capture-recapture models which should be useful in paleobiological analyses and discuss the assumptions which underlie them. We illustrate these models with examples and discuss aspects of study design. We conclude that these models should prove useful in paleobiological analyses.", "keyphrases": ["speciation rate", "fossil data", "capture-recapture model"]}
{"id": "10.1002/ajpa.23646", "title": "Latitude, urbanization, age, and sex as risk factors for vitamin D deficiency disease in the Roman Empire.", "abstract": "OBJECTIVES\nThe aims of the study are to investigate the effects of latitude, settlement type, age, and sex on the prevalence of vitamin D deficiency disease in the Roman Empire using human skeletal remains from cemetery sites (1st to 6th cent. AD).\n\n\nMATERIALS AND METHODS\nData from 2,787 individuals (1,143 subadults, 1,644 adults) from 18 cemeteries associated with 15 different settlements in the Mediterranean and north-western Europe were analyzed. Vitamin D deficiency disease (rickets, osteomalacia) was identified using standard paleopathological criteria. Multivariate statistical analysis was used analyze the effects of the variables of interest on the prevalence of vitamin D deficiency.\n\n\nRESULTS\nThe overall prevalence of rickets in subadults (<20\u2009years) was 5.7%, and 3.2% of adults showed osteomalacia and/or residual rickets. There was a positive association between rickets in subadults and latitude, with numerous cases of rickets among infants. There was no general association with sex or settlement type, although an elevated prevalence of rickets was observed at a cemetery associated with a settlement (Ostia, Italy), which had multi-storey buildings.\n\n\nDISCUSSION\nThe association of rickets with latitude may reflect care practices that, in more northerly locations where solar radiation is less intense, placed infants at increased risk of insufficient sunlight exposure to permit adequate vitamin D biosynthesis. The elevated level of vitamin D deficiency at Ostia may reflect, at least in part, the lack of sunlight due to dense occupation of multi-storey blocks that prevented direct sunlight from reaching living quarters and the streets between these closely spaced buildings.", "keyphrases": ["vitamin", "deficiency disease", "variable", "latitude"]}
{"id": "paleo.009594", "title": "Craniodental Morphology and Systematics of a New Family of Hystricognathous Rodents (Gaudeamuridae) from the Late Eocene and Early Oligocene of Egypt", "abstract": "Background Gaudeamus is an enigmatic hystricognathous rodent that was, until recently, known solely from fragmentary material from early Oligocene sites in Egypt, Oman, and Libya. Gaudeamus' molars are similar to those of the extant cane rat Thryonomys, and multiple authorities have aligned Gaudeamus with Thryonomys to the exclusion of other living and extinct African hystricognaths; recent phylogenetic analyses have, however, also suggested affinities with South American caviomorphs or Old World porcupines (Hystricidae). Methodology/Principal Findings Here we describe the oldest known remains of Gaudeamus, including largely complete but crushed crania and complete upper and lower dentitions. Unlike younger Gaudeamus species, the primitive species described here have relatively complex occlusal patterns, and retain a number of plesiomorphic features. Unconstrained parsimony analysis nests Gaudeamus and Hystrix within the South American caviomorph radiation, implying what we consider to be an implausible back-dispersal across the Atlantic Ocean to account for Gaudeamus' presence in the late Eocene of Africa. An analysis that was constrained to recover the biogeographically more plausible hypothesis of caviomorph monophyly does not place Gaudeamus as a stem caviomorph, but rather as a sister taxon of hystricids. Conclusions/Significance We place Gaudeamus species in a new family, Gaudeamuridae, and consider it likely that the group originated, diversified, and then went extinct over a geologically brief period of time during the latest Eocene and early Oligocene in Afro-Arabia. Gaudeamurids are the only known crown hystricognaths from Afro-Arabia that are likely to be aligned with non-phiomorph members of that clade, and as such provide additional support for an Afro-Arabian origin of advanced stem and basal crown members of Hystricognathi.", "keyphrases": ["hystricognathous rodent", "gaudeamuridae", "late eocene"]}
{"id": "10.2307/3515259", "title": "Trilobite taphonomy and taxonomy; a problem and some implications", "abstract": "Recent advances in trilobite taphonomy have highlighted the importance of sclerite preservation for understanding sedimentary processes and aspects of trilobite paleoecology (Speyer and Brett, 1985, 1986; Westrop, 1986; Babcock and Speyer, 1987; Speyer, 1987, 1988). The effect of taphonomy on trilobite taxonomy has received less attention. Consequently, it is not possible to evaluate the broader effects of taphonomy on our understanding of evolution and biogeography, and some recent studies of evolutionary patterns within the group (e.g., Foote, 1990, 1991, 1993) have been restricted to forms occurring within particular lithofacies. Numerous systematic papers discuss how preservation affects particular characters or character sets. Examples include the effects of compaction on sclerite morphology in specimens preserved in fine grain clastic sediments (e.g., Kiaer, 1917; Fortey, 1974), differences between carbonate and clastic preservation (e.g., Taylor, 1978), the differences in the morphology of internal and external molds (e.g., Jell, 1985), and how taphonomic artifacts have been mistaken for biological features (Hughes, 1993). However, such examples refer to specific instances, and are of limited use in evaluating the broader implications of taphonomy on trilobite taxonomy. As taphonomic conditions vary markedly between sedimentary environments, the effects of taphonomy on trilobite systematics are likely to be greatest on those taxa which occur in a wide range of lithofacies. Such taxa are often the most useful for providing inter-regional correlations and hence have critical significance for biogeography and biostratigraphy. Here I present a brief illustrative example of the potential effects of taphonomy on the taxonomy of one trilobite, the middle Cambrian conocoryphid Bailiella, and a discussion of the implications of this example for other areas of paleontology. Bailiella is an appropriate trilobite to use as an example for several reasons. Firstly, as an eyeless conocoryphid trilobite its morphology is distinct from that of many generalized \"ptychopariid\" trilobites, with which it is co-occurrent. Its distinctiveness allows us to be relatively confident of its identification, despite the taphonomic differences detailed below. Secondly, the genus is widespread and occurs in a variety of paleoenvironments. A revision of the systematics of Bailiella species from China, Vietnam, India and Siberia, indicates that the position of the facial suture (cutting the border) provides a consistent characteristic that can be used to recognize the species B. lantenoisi (see Zhang and Jell, 1987, pl. 35, figs. 1-7). This species is found both in shelfal carbonate settings (China and Siberia), where it is usually found as disarticulated sclerites, and in finegrain clastic slope deposits (Vietnam and India) where it occurs both as articulated dorsal shields and as disarticulated sclerites. These different preservation styles present alternative character suites to the systematist. For example, cranidia preserved in carbonates possess original relief and fine details of surface ornament. The preservation potential of these types of features is reduced in specimens preserved in shales, because the skeletal material is often absent and the specimens are compressed composite molds. The presence of articulated dorsal exoskeletons in this type of setting, however, provides a suite of characteristics that are not available for evaluation in specimens from shelf carbonates. Such characteristics include the number of thoracic segments, and the overall body proportions. Peter Jell and I are preparing a redescription of B. lantenoisi that lists some 38 \"major\" characters (Table 1). Parentheses are used here because the question of what constitutes a character is subjective in any systematic analysis (see Adrain and Chatterton, 1990), and character choice is especially difficult when the morphology includes both biological and preservational components. Another systematist would not describe an identical set of characters, but the magnitude of preservational factors documented below far outweighs slight differences of character interpretation. The greater number of characters listed for the cranidium (23) than for the remainder of the dorsal exoskeleton (15) (Table 1) reflects the concentration of distinctive morphological features on that sclerite. Of the 38 characters, only 14 appear to have resisted modification by preservational biases, and can be compared with confidence in specimens from all lithofacies settings (Table 1). Variation in any of these 14 characters could potentially be used to define different taxa, but apparently does not do so in this case. Of the remaining 24 characters we can be less confident. 18 characteristics can only be coded with confidence in specimens from carbonates preserving relief and fine detail, 4 are codable only in articulated dorsal shields, presently known only from slope settings, and 2 cannot be coded with confidence in either setting. Each of these 24 characteristics could potentially indicate taxonomic differences between B. lantenoisi collections preserved in different taphonomic settings. However, as these", "keyphrases": ["taphonomy", "taxonomy", "trilobite taphonomy"]}
{"id": "paleo.001562", "title": "Simulating sauropod manus-only trackway formation using finite-element analysis", "abstract": "The occurrence of sauropod manus-only trackways in the fossil record is poorly understood, limiting their potential for understanding locomotor mechanics and behaviour. To elucidate possible causative mechanisms for these traces, finite-element analyses were conducted to model the indentation of substrate by the feet of Diplodocus and Brachiosaurus. Loading was accomplished by applying mass, centre of mass and foot surface area predictions to a range of substrates to model track formation. Experimental results show that when pressure differs between manus and pes, as determined by the distribution of weight and size of respective autopodia, there is a range of substrate shear strengths for which only the manus (or pes) produce enough pressure to deform the substrate, generating a track. If existing reconstructions of sauropod feet and mass distributions are correct, then different taxa will produce either manus- or pes-only trackways in specific substrates. As a result of this work, it is predicted that the occurrence of manus- or pes-only trackways may show geo-temporal correlation with the occurrence of body fossils of specific taxa.", "keyphrases": ["sauropod manus-only trackway", "manus-only trackway", "finite-element analysis"]}
{"id": "paleo.012366", "title": "Genetic contributions to variation in human stature in prehistoric Europe", "abstract": "Significance Measurements of prehistoric human skeletal remains provide a record of changes in height and other anthropometric traits over time. Often, these changes are interpreted in terms of plastic developmental response to shifts in diet, climate, or other environmental factors. These changes can also be genetic in origin, but, until recently, it has been impossible to separate the effects of genetics and environment. Here, we use ancient DNA to directly estimate genetic changes in phenotypes and to identify changes driven not by genetics, but by environment. We show that changes over the past 35,000 y are largely predicted by genetics but also identify specific shifts that are more likely to be environmentally driven. The relative contributions of genetics and environment to temporal and geographic variation in human height remain largely unknown. Ancient DNA has identified changes in genetic ancestry over time, but it is not clear whether those changes in ancestry are associated with changes in height. Here, we directly test whether changes over the past 38,000 y in European height predicted using DNA from 1,071 ancient individuals are consistent with changes observed in 1,159 skeletal remains from comparable populations. We show that the observed decrease in height between the Early Upper Paleolithic and the Mesolithic is qualitatively predicted by genetics. Similarly, both skeletal and genetic height remained constant between the Mesolithic and Neolithic and increased between the Neolithic and Bronze Age. Sitting height changes much less than standing height\u2014consistent with genetic predictions\u2014although genetics predicts a small post-Neolithic increase that is not observed in skeletal remains. Geographic variation in stature is also qualitatively consistent with genetic predictions, particularly with respect to latitude. Finally, we hypothesize that an observed decrease in genetic heel bone mineral density in the Neolithic reflects adaptation to the decreased mobility indicated by decreased femoral bending strength. This study provides a model for interpreting phenotypic changes predicted from ancient DNA and demonstrates how they can be combined with phenotypic measurements to understand the relative contribution of genetic and developmentally plastic responses to environmental change.", "keyphrases": ["contribution", "stature", "height", "genetic contribution"]}
{"id": "10.1111/j.1469-7998.2006.00094.x", "title": "Estimating the body mass of extinct ungulates: a study on the use of multiple regression", "abstract": "The correlation between body mass and both skeletal and dental measures in living mammals has enabled paleontologists to obtain reliable estimates of body size for extinct species, usually using log-transformed bivariate least-squares regression equations. Multiple regression, however, has rarely been used for estimating the mass of extinct species, although this technique can clearly improve the predictive equations compared with those adjusted by simple regression. However, the use of multiple regression is problematical, because even those functions explaining a high percentage of the variance of the dependent variable (i.e. body mass) can show a rather limited predictive power. After analyzing which factors determine the predictive ability of multiple regression equations, we propose a new set of algorithms that allow the estimation of the body mass of extinct ungulates. These algorithms are finally applied to three Miocene ungulate species, Dinohippus leidyanus, Stenomylus hitchcocki and Aletomeryx scotti.", "keyphrases": ["body mass", "extinct ungulate", "multiple regression"]}
{"id": "paleo.010594", "title": "Time-calibrated molecular phylogeny of pteropods", "abstract": "Pteropods are a widespread group of holoplanktonic gastropod molluscs and are uniquely suitable for study of long-term evolutionary processes in the open ocean because they are the only living metazoan plankton with a good fossil record. Pteropods have been proposed as bioindicators to monitor the impacts of ocean acidification and in consequence have attracted considerable research interest, however, a robust evolutionary framework for the group is still lacking. Here we reconstruct their phylogenetic relationships and examine the evolutionary history of pteropods based on combined analyses of Cytochrome Oxidase I, 28S, and 18S ribosomal rRNA sequences and a molecular clock calibrated using fossils and the estimated timing of the formation of the Isthmus of Panama. Euthecosomes with uncoiled shells were monophyletic with Creseis as the earliest diverging lineage, estimated at 41\u201338 million years ago (mya). The coiled euthecosomes (Limacina, Heliconoides, Thielea) were not monophyletic contrary to the accepted morphology-based taxonomy; however, due to their high rate heterogeneity no firm conclusions can be drawn. We found strong support for monophyly of most euthecosome genera, but Clio appeared as a polyphyletic group, and Diacavolinia grouped within Cavolinia, making the latter genus paraphyletic. The highest evolutionary rates were observed in Heliconoides inflatus and Limacina bulimoides for both 28S and 18S partitions. Using a fossil-calibrated phylogeny that sets the first occurrence of coiled euthecosomes at 79\u201366 mya, we estimate that uncoiled euthecosomes evolved 51\u201342 mya and that most extant uncoiled genera originated 40\u201315 mya. These findings are congruent with a molecular clock analysis using the Isthmus of Panama formation as an independent calibration. Although not all phylogenetic relationships could be resolved based on three molecular markers, this study provides a useful resource to study pteropod diversity and provides general insight into the processes that generate and maintain their diversity in the open ocean.", "keyphrases": ["phylogeny", "pteropod", "creseis", "limacina"]}
{"id": "10.1098/rspb.2012.0211", "title": "Dental functional traits of mammals resolve productivity in terrestrial ecosystems past and present", "abstract": "We have recently shown that rainfall, one of the main climatic determinants of terrestrial net primary productivity (NPP), can be robustly estimated from mean molar tooth crown height (hypsodonty) of mammalian herbivores. Here, we show that another functional trait of herbivore molar surfaces, longitudinal loph count, can be similarly used to extract reasonable estimates of rainfall but also of temperature, the other main climatic determinant of terrestrial NPP. Together, molar height and the number of longitudinal lophs explain 73 per cent of the global variation in terrestrial NPP today and resolve the main terrestrial biomes in bivariate space. We explain the functional interpretation of the relationships between dental function and climate variables in terms of long- and short-term demands. We also show how the spatially and temporally dense fossil record of terrestrial mammals can be used to investigate the relationship between biodiversity and productivity under changing climates in geological time. The placement of the fossil chronofaunas in biome space suggests that they most probably represent multiple palaeobiomes, at least some of which do not correspond directly to any biomes of today's world.", "keyphrases": ["functional trait", "productivity", "rainfall"]}
{"id": "10.1046/j.1471-0528.2002.00010.x", "title": "Birth, obstetrics and human evolution", "abstract": "There are several characteristics that set our species apart from other mammals. We are the only living or extant mammal that habitually walks on two legs. For our body size, we have the largest and the most complex brains of all animals. Humans depend on material culture or \u2018tools\u2019 for their survival. Humans universally communicate with each other through abstract symbols known as language. Finally, human females routinely seek assistance when they give birth. In fact, many have argued that midwifery or obstetrics, not prostitution, is the \u2018oldest profession\u2019. Fossil evidence shows that although two-legged walking, or bipedalism, traces its origin to the very beginning of human ancestry, tools and language appeared much more recently in human evolution. We will argue in this paper that, along with bipedalism, some aspects of the human pattern of birth trace their origin to the very beginning of human evolution. Based on fossil evidence from Africa, human paleontologists agree that the mammalian family to which humans belong, Hominidae (\u2018hominids\u2019), originated approximately 5 million years ago. The crucial hallmarks of our earliest hominid ancestors are skeletal indicators of bipedalism. These markers appear clearly first in Australopithecus anamensis (ca. 4 million years ago) or possibly earlier. In spite of a human pattern of locomotion, these early members of the genus Australopithecus had brains that were smaller than modern humans\u2014in proportion to their bodies\u2014very similar to those of modern chimpanzees. Significant brain expansion did not begin until the origin of our genus, Homo, about 2.5 million years ago, when we also have evidence of the first stone tools. Evidence of language is not directly preserved in the fossil record but several investigators suggest that our ancestors were capable of the complex speech patterns that are part of all spoken languages today by at least 200,000 years ago. As noted above, we argue that assisted birth may be associated with bipedalism, and may thus be as old as the hominid family itself. However, assistance at birth is not the only significant birthrelated difference between humans and our close relatives in the primate order. The unusual way in which modern humans give birth is the result of a set of constraints imposed by bipedalism, a large brain, and \u2018secondary altriciality\u2019, or the delivery of the infant in a relatively helpless state. Birth in non-human primates", "keyphrases": ["obstetric", "human evolution", "assistance", "non-human primate", "birth"]}
{"id": "paleo.008167", "title": "Fossil lizards and worm lizards (Reptilia, Squamata) from the Neogene and Quaternary of Europe: an overview", "abstract": "Lizards were and still are an important component of the European herpetofauna. The modern European lizard fauna started to set up in the Miocene and a rich fossil record is known from Neogene and Quaternary sites. At least 12 lizard and worm lizard families are represented in the European fossil record of the last 23 Ma. The record comprises more than 3000 occurrences from more than 800 localities, mainly of Miocene and Pleistocene age. By the beginning of the Neogene, a marked faunistic change is detectable compared to the lizard fossil record of Palaeogene Europe. This change is reflected by other squamates as well and might be related to an environmental deterioration occurring roughly at the Oligocene/ Miocene boundary. Nevertheless, the diversity was still rather high in the Neogene and started to decrease with the onset of the Quaternary glacial cycles. This led to the current impoverished lizard fauna, with the southward range shrinking of the most thermophilic taxa (e.g., agamids, amphisbaenians) and the local disappearance of other groups (e.g., varanids). Our overview of the known fossil record of European Neogene and Quaternary lizards and worm lizards highlighted a substantial number of either unpublished or poorly known occurrences often referred to wastebasket taxa. A proper study of these and other remains, as well as a better sampling of poorly explored time ranges (e.g., Pliocene, Holocene), is needed and would be of utmost importance to better understand the evolutionary history of these reptiles in Europe.", "keyphrases": ["worm lizard", "europe", "miocene"]}
{"id": "10.1002/spp2.1262", "title": "The bivalved arthropod Tuzoia from the Balang Formation (Cambrian Stage 4) of Guizhou, China, and new observations on comparative species", "abstract": "Tuzoia is a large, bivalved Cambrian arthropod having a widespread distribution in shallow\u2010shelf to deeper marine Lagerst\u00e4tten; stratigraphically it ranges from Cambrian Series 2 through the Miaolingian Series. In the present study, three species are recognized from relatively deep\u2010water deposits of the Balang Formation (Cambrian Stage 4) of Guizhou, South China: Tuzoia sinensis Pan, 1957, T. bispinosa Yuan et Zhao, 1999 and T. lazizhaiensis sp. nov. The new species is unique in having 6\u201310 small marginal spines on the dorsal margin, an inflated anterior margin with three short, closely spaced marginal spines. These remains, which usually occur as disarticulated valves, are inferred to be parautochthonous. One new specimen of T. lazizhaiensis shows a stalked eye and antenna. New Tuzoia material from the Kaili Biota (Cambrian: Wuliuan Stage) of Guizhou, and from the Guanshan Biota (Cambrian Stage 4) of Yunnan, China, provide additional comparative information about the genus. Some new specimens of T. bispinosa from the Kaili Biota provide information on valve morphology and palaeoecology. One specimen of T. sinensis from the Guanshan Biota provides information on the appendages, and one specimen of T. tylodesa, from the Guanshan Biota adds provides information on the trunk and appendages.", "keyphrases": ["arthropod", "tuzoia", "cambrian stage"]}
{"id": "paleo.002842", "title": "The rise of the ruling reptiles and ecosystem recovery from the Permo-Triassic mass extinction", "abstract": "One of the key faunal transitions in Earth history occurred after the Permo-Triassic mass extinction (ca 252.2 Ma), when the previously obscure archosauromorphs (which include crocodylians, dinosaurs and birds) become the dominant terrestrial vertebrates. Here, we place all known middle Permian\u2013early Late Triassic archosauromorph species into an explicit phylogenetic context, and quantify biodiversity change through this interval. Our results indicate the following sequence of diversification: a morphologically conservative and globally distributed post-extinction \u2018disaster fauna\u2019; a major but cryptic and poorly sampled phylogenetic diversification with significantly elevated evolutionary rates; and a marked increase in species counts, abundance, and disparity contemporaneous with global ecosystem stabilization some 5 million years after the extinction. This multiphase event transformed global ecosystems, with far-reaching consequences for Mesozoic and modern faunas.", "keyphrases": ["reptile", "permo-triassic mass extinction", "mass extinction", "faunal transition", "early triassic"]}
{"id": "10.5194/egusphere-egu2020-5483", "title": "Aquatic ecosystems in Miocene western Amazonia \u2013 marine ingressions vs. salt leaching", "abstract": "Before the onset of the modern Amazon river system, north-western South America was shaped by an extensive wetland during the Miocene. This \u2018Pebas mega-wetland\u2019 kept a well renowned endemic mollusk and ostracod fauna, which initiated a persisting debate about marine ingressions reaching the center of Amazonia at that time. Due to high endemism, uniformitarian principles are hardly applicable to this biota but also other paleontological, sedimentological and geochemical information led to ambiguous paleoenvironmental interpretations. These results are based on ostracod and foraminiferal assemblages and the oxygen and carbon stable isotopy of their biogenic calcite from an outcrop at the cutbank of the Amazon river (NE-Peru, ~55 km S of Iquitos). While ostracods (e.g., Cyprideis) are able to calcify their carapaces along the entire salinity range, at least low saline conditions are a prerequisite for the biomineralization of calcareous foraminiferan tests. Hence, the finding of calcareous foraminifers (Ammonia, Elphidium), associated mainly with brackish water ostracods, indicates the presence of saline waters. In contrast, \u03b4 18 Oand \u03b4 13 C-analyses performed on co-occurring ostracod valves and foraminiferan tests yielded constantly very light ratios. Such values refer to a pure freshwater environment and are incompatible with the interference of isotopically heavier, marine waters or an evaporative stable isotope enrichment. Based on these opposing data, we hypothesize that the Pebas megawetland was episodically influenced by mineralized but isotopically light groundwater discharge. Possibly, the resulting specific hydrochemistry contributed not only to the evolution of the endemic Pebasian fauna but also facilitated the sporadic settlement of euryhaline foraminifers, which mimics short-lived marine incursions.", "keyphrases": ["miocene", "amazonia", "marine ingression", "saltwater organism", "ground water release"]}
{"id": "10.1080/14772000.2012.748697", "title": "Taxonomy-testing and the \u2018Goldilocks Hypothesis\u2019: morphometric analysis of species diversity in living and extinct Hispaniolan hutias", "abstract": "Understanding the dynamics of the Late Quaternary Caribbean mammal extinction event is complicated by continuing uncertainty over the taxonomic status of many species. Hispaniola is one of the few Caribbean islands to retain native non-volant mammals; however, there has been little consensus over past or present levels of diversity in Hispaniolan hutias (Capromyidae: Plagiodontinae). Craniodental measurement data from modern hutia specimens, previously classified as both Plagiodontia aedium and P. hylaeum, display morphological differences between Hispaniola's northern and southern palaeo-islands using MANOVA and PCA. Although attempts to amplify mitochondrial DNA from the holotype of P. aedium were unsuccessful, this specimen is morphometrically associated with southern palaeo-island specimens. The mandibular size distribution of recent Plagiodontia specimens is unimodal, but the Late Quaternary mandibular size distribution is multimodal and displays much broader measurement spread, representing multiple extinct species. Finite Mixture Analysis was used to assess the best fit of different taxonomic hypotheses to the fossil mandibular size distribution. All retained FMA models include living hutias and P. spelaeum as distinct taxa; PCA further demonstrates that levels of morphological variation between modern hutia populations are lower than levels between living hutias and P. spelaeum, so that living hutias are interpreted as the single species P. aedium. Taxonomic differentiation for larger-bodied hutias is less well defined, but most retained models show only one larger species, for which the only available name is P. velozi. \u2018Plagiodontia\u2019 araeum is morphologically distinct from other species and is reassigned to Hyperplagiodontia. Hispaniola's plagiodontine fauna has lost its largest and smallest representatives; similar trends of body size selectivity in extinction risk are shown more widely across the Caribbean mammal fauna, possibly due to different regional anthropogenic threats (invasive mammals, hunting) affecting small-bodied and large-bodied mammals during the recent past. This apparent pattern of extinction selectivity is named the \u2018Goldilocks Hypothesis\u2019.", "keyphrases": ["goldilocks hypothesis", "hispaniolan hutia", "invasive mammal"]}
{"id": "paleo.004014", "title": "Oldest known avian footprints from Australia: Eumeralla Formation (Albian), Dinosaur Cove, Victoria", "abstract": "Two thin\u2010toed tridactyl tracks in a fluvial sandstone bed of the Eumeralla Formation (Albian) at Dinosaur Cove (Victoria, Australia) were likely made by avian trackmakers, making these the oldest known fossil bird tracks in Australia and the only Early Cretaceous ones from Gondwana. These tracks, which co\u2010occur on the same surface with a slightly larger nonavian theropod track, are distinguishable by their anisodactyl form, hallux impressions and wide digit II\u2013IV divarication angles. A lengthy hallux impression and other deformational structures associated with one track indicate foot movement consistent with an abrupt stop, suggesting its tracemaker landed after either flight or a hop. The single nonavian theropod track is similar to other tracks described from the Eumeralla Formation at another locality. The avian footprints are larger than most Early Cretaceous avian tracks recorded worldwide, indicating sizeable enantiornithine or ornithurine species in formerly polar environments of Australia. The avian tracks further supplement scant body fossil evidence of Early Cretaceous birds in southern Australia, which includes a furcula from the Wonthaggi Formation. Because of this discovery, Dinosaur Cove, previously known for its vertebrate body fossils, is added to a growing list of Early Cretaceous vertebrate tracksites in southern Australia.", "keyphrases": ["footprint", "eumeralla formation", "dinosaur cove", "impression"]}
{"id": "paleo.008106", "title": "High-quality fossil dates support a synchronous, Late Holocene extinction of devils and thylacines in mainland Australia", "abstract": "The last large marsupial carnivores\u2014the Tasmanian devil (Sarcophilis harrisii) and thylacine (Thylacinus cynocephalus)\u2014went extinct on mainland Australia during the mid-Holocene. Based on the youngest fossil dates (approx. 3500 years before present, BP), these extinctions are often considered synchronous and driven by a common cause. However, many published devil dates have recently been rejected as unreliable, shifting the youngest mainland fossil age to 25 500 years BP and challenging the synchronous-extinction hypothesis. Here we provide 24 and 20 new ages for devils and thylacines, respectively, and collate existing, reliable radiocarbon dates by quality-filtering available records. We use this new dataset to estimate an extinction time for both species by applying the Gaussian-resampled, inverse-weighted McInerney (GRIWM) method. Our new data and analysis definitively support the synchronous-extinction hypothesis, estimating that the mainland devil and thylacine extinctions occurred between 3179 and 3227 years BP.", "keyphrases": ["devil", "mainland australia", "radiocarbon date"]}
{"id": "10.1080/14772019.2013.776646", "title": "Biogeographical implications of a new mouse-sized fossil bandicoot (Marsupialia: Peramelemorphia) occupying a dasyurid-like ecological niche across Australia", "abstract": "We describe Bulungu palara gen. et sp. nov., a new fossil peramelemorphian (bandicoot), based on a single well-preserved skull and additional dental specimens from Late Oligocene to Middle Miocene (Faunal Zones A\u2013C) limestone deposits at the Riversleigh World Heritage Property, Queensland, and two dental specimens from the Early\u2013Middle Miocene Kutjamarpu Local Fauna, South Australia. This is the first fossil peramelemorphian species to be reported from more than a single fossil fauna, with its inferred distribution extending from north-western Queensland (modern latitude \u223c19\u00b0S) to north-eastern South Australia (modern latitude \u223c28\u00b0S). The presence of Bulungu palara in Riversleigh Faunal Zones A, B and C and in the Kutjamarpu Local Fauna supports the current interpretation that these faunas span similar ages, namely Late Oligocene\u2013Middle Miocene. Phylogenetic analyses of an expanded 74 morphological character dataset using maximum parsimony and Bayesian approaches, both with and without a molecular scaffold, consistently place Bulungu and the Oligo-Miocene forms Galadi and Yarala outside crown-group Peramelemorphia. These analyses also fail to support a close relationship between the Pliocene Ischnodon australis (previously considered the oldest known representative of the extant peramelemorphian family Thylacomyidae) and the modern thylacomyid genus Macrotis. With an estimated body mass of \u223c130 g, Bulungu palara is smaller than any known Recent bandicoot from Australia, although some modern New Guinean species are similar in size. The small size and craniodental morphology of B. palara suggest that it was predominantly or exclusively insectivorous, perhaps ecologically similar to small New Guinean dasyurids such as Murexechinus melanurus. Together with the small-bodied (< 100 g), insectivorous Yarala burchfieldi and large-bodied (\u223c900 g), faunivorous Galadi speciosus, Bulungu palara demonstrates that Oligo-Miocene Australian peramelemorphians filled ecological niches that today are mostly occupied by dasyurids, and that a major faunal turnover event occurred at some point after the Middle Miocene. http://zoobank.org/urn:lsid:zoobank.org:pub:18955DCC-DB8C-4216-AF38-921E1E5C1F79", "keyphrases": ["peramelemorphia", "ecological niche", "late oligocene"]}
{"id": "10.1002/jmor.10659", "title": "Body mass estimation in xenarthra: A predictive equation suitable for all quadrupedal terrestrial placentals?", "abstract": "The Magnorder Xenarthra includes strange extinct groups, like glyptodonts, similar to large armadillos, and ground sloths, terrestrial relatives of the extant tree sloths. They have created considerable paleobiological interest in the last decades; however, the ecology of most of these species is still controversial or unknown. The body mass estimation of extinct species has great importance for paleobiological reconstructions. The commonest way to estimate body mass from fossils is through linear regression. However, if the studied species does not have similar extant relatives, the allometric pattern described by the regression could differ from those shown by the extinct group. That is the case for glyptodonts and ground sloths. Thus, stepwise multiple regression were developed including extant xenarthrans (their taxonomic relatives) and ungulates (their size and ecological relatives). Cases were weighted to maximize the taxonomic evenness. Twenty\u2010eight equations were obtained. The distribution of the percent of prediction error (%PE) was analyzed between taxonomic groups (Perissodactyla, Artiodactyla, and Xenarthra) and size groups (0\u201320 kg, 20\u2013300 kg, and more than 300 kg). To assess the predictive power of the functions, equations were applied to species not included in the regression development [test set cross validation, (TSCV)]. Only five equations had a homogeneous %PE between the aforementioned groups. These were applied to five extinct species. A mean body mass of 80 kg was estimated for Propalaehoplophorus australis (Cingulata: Glyptodontidae), 594 kg for Scelidotherium leptocephalum (Phyllophaga: Mylodontidae), and 3,550.7 kg for Lestodon armatus (Phyllophaga: Mylodontidae). The high scatter of the body mass estimations obtained for Catonyx tarijensis (Phyllophaga: Mylodontidae) and Thalassocnus natans (Phyllophaga: Megatheriidae), probably due to different specializations, prevented us from predicting its body mass. Surprisingly, although obtained from ungulates and xenarthrans, these five selected equations were also able to predict the body mass of species from groups as different as rodents, carnivores, hyracoideans, or tubulidentates. This result suggests the presence of a complex common allometric pattern for all quadrupedal placentals. J. Morphol., 2008. \u00a9 2008 Wiley\u2010Liss, Inc.", "keyphrases": ["xenarthra", "equation", "ground sloth", "body mass estimation"]}
{"id": "10.1080/14772019.2015.1136900", "title": "New bivalves from a Middle Devonian methane seep in Morocco: the oldest record of repetitive shell morphologies among some seep bivalve molluscs", "abstract": "A fauna of bivalve molluscs is described from methane seep carbonates of the Middle Devonian (c. 390 Ma) Hollard Mound in the eastern Anti-Atlas, Morocco. We describe a new modiomorphid genus Ataviaconcha gen. nov. with the type species Ataviaconcha wendti sp. nov. This is a very large, semi-infaunal species occurring in large colonies similar to those formed by Recent chemosymbiotic cold-seep and hydrothermal vent bivalves. It is the second modiomorphid bivalve known from Palaeozoic chemosynthesis-based ecosystems, after the roughly coeval Sibaya ivanovi Little, Maslennikov, Morris & Gubanov, 1999, from the Sibay hydrothermal vent deposit in the Ural Mountains, Russia. The second and much less numerous bivalve species described in this paper is the solemyid Dystactella? eisenmanni sp. nov., belonging to a genus known also from Ordovician to Devonian marine environments distinct from cold seeps and hydrothermal vents. As with other fossil and Recent solemyids, it was an infaunal burrower, most likely living in symbiosis with chemoautotrophic bacteria. These new findings show that bivalves are ancient in chemosynthesis-based ecosystems, thriving there for at least 390 Myr, and that the bivalve-dominated faunas predated the first occurrence of dimerelloid brachiopods at seeps. The early evolutionary adaptation of some bivalves to chemosynthesis-based ecosystems is probably related to a symbiosis-based metabolism allowing efficient exploitation of chemosynthetic food resources. Ataviaconcha wendti sp. nov. represents a morphology which recurred several times throughout the following 390 Myr in different bivalve groups that flourished at hydrocarbon seeps. This strongly suggests environmental control on the evolution of adaptations in seep biotas. http://zoobank.org/urn:lsid:zoobank.org:pub:A83D5CB1-67D2-4D05-8EBC-BFCA6E6845D8", "keyphrases": ["bivalve", "morocco", "brachiopod"]}
{"id": "10.5670/oceanog.2011.57", "title": "A Synthesis of the Long-Term Paleoclimatic Evolution of the Arctic", "abstract": "Since the Arctic Ocean began forming in the Early Cretaceous 112\u2013140 million years ago, the Arctic region has undergone profound oceanographic and paleoclimatic changes. It has evolved from a warm epicontinental sea to its modern state as a cold isolated ocean with extensive perennial sea ice cover. Our understanding of the long-term paleoclimate evolution of the Arctic remains fragmentary but has advanced dramatically in the past decade through analysis of new marine and terrestrial records, supplemented by important insights from paleoclimate models. Improved understanding of how these observations fit into the long-term evolution of the global climate system requires additional scientific drilling in the Arctic to provide detailed and continuous paleoclimate records, and to resolve the timing and impact of key tectonic and physiographic changes to the ocean basin and surrounding landmasses. Here, we outline the long-term paleoclimatic evolution of the Arctic, with a focus on integrating both terrestrial and marine records.", "keyphrases": ["long-term paleoclimatic evolution", "arctic", "arctic ocean"]}
{"id": "10.1126/science.aay5055", "title": "On impact and volcanism across the Cretaceous-Paleogene boundary", "abstract": "An impact with a dash of volcanism Around the time of the end-Cretaceous mass extinction that wiped out dinosaurs, there was both a bolide impact and a large amount of volcanism. Hull et al. ran several temperature simulations based on different volcanic outgassing scenarios and compared them with temperature records across the extinction event. The best model fits to the data required most outgassing to occur before the impact. When combined with other lines of evidence, these models support an impact-driven extinction. However, volcanic gases may have played a role in shaping the rise of different species after the extinction event. Science, this issue p. 266 The primary cause of the end-Cretaceous mass extinction was an impact, with volcanism playing a role in the aftermath. The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing. We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.", "keyphrases": ["volcanism", "end-cretaceous mass extinction", "bolide impact", "cause", "warming"]}
{"id": "10.1111/j.1502-3931.2007.00024.x", "title": "New insights into the ultrastructure, permeability, and integrity of conodont apatite determined by transmission electron microscopy", "abstract": "New crystalline structures have been observed in argon ion-milled conodont elements from a diverse suite of Ordovician taxa (\u2018Cordylodus robustus\u2019, Drepanoistodus suberectus, Panderodus gracilis, Plectodina? sp., Aphelognathus sp., Periodon aculeatus), using transmission electron microscopy (TEM). Electron diffraction patterns of albid tissue reveal that the component crystals are extraordinarily large, in the order of hundred(s) of microns. These large albid crystals show typical cancellate porosity, although a distinctly lamellar structure has also been observed within a large albid crystal positioned between hyaline lamellar and cancellate albid tissues. There is a distinct absence of \u2018interlamellar space\u2019 within all hyaline tissues examined, which are characterized by a polycrystalline matrix of micron-scale elongate crystals that are both strongly aligned and tightly bound within a broader lamellar structure. Optical opacity, caused by light scattering within large (\u2265\u00a00.5 \u00b5m) pores, is also a feature of both albid and polycrystalline lamellar crown tissues. Accordingly, conodont hard tissues are differentiated by crystal size and shape, as well as inter- and intracrystalline porosity. \n \n \n \nThese new observations highlight the structural complexities of conodont histologies and the need for more comprehensive investigations particularly of transitional crown tissues, which are not well defined by terms typically used in the literature. Their histological structures are interpreted to be a product of in vivo crystallization and thus provide new insights into the relative porosity, permeability, and inherent integrity of the tissues as well as their growth relationships. Accordingly, these data not only have implications for earlier histological and palaeobiological interpretations of conodont hard tissues but are also fundamental in determining their chemical integrity, which is crucial for characterizing palaeoseawater composition and palaeoenvironmental change. The potential for conodont apatite to retain primary chemical information depends on crystal size and permeability, so the large albid crystal domains are consistent with parallel geochemical studies that suggest that cancellate albid crown is more resistant to diagenetic modification.", "keyphrases": ["permeability", "conodont apatite", "transmission electron microscopy", "crystal", "matrix"]}
{"id": "paleo.004317", "title": "Systematics and Evolution of the Miocene Three-Horned Palaeomerycid Ruminants (Mammalia, Cetartiodactyla)", "abstract": "Palaeomerycids were strange three-horned Eurasian Miocene ruminants known through fossils from Spain to China. We here study their systematics, offering the first cladistic phylogeny of the best-known species of the group, and also reassess their phylogenetic position among ruminants, which is currently disputed. The beautifully preserved remains of a new palaeomerycid from middle Miocene deposits of Spain, Xenokeryx amidalae gen. et sp. nov., helps us to better understand palaeomerycid anatomy, especially that of the nuchal region in the skull, significantly improving our current knowledge on these enigmatic ruminants. Our results show two main lineages of palaeomerycids, one containing the genus Ampelomeryx diagnosed by a characteristic type of cranium / cranial appendages and some dental derived traits, and another one that clusters those forms more closely related to Triceromeryx than to Ampelomeryx, characterized by a more derived dentition and a set of apomorphic cranial features. Xenokeryx branches as a basal offshoot of this clade. Also, we find that Eurasian palaeomerycids are not closely related to North American dromomerycids, thus rejecting the currently more accepted view of palaeomerycids as the Eurasian part of the dromomerycid lineage. Instead of this, palaeomerycids are nested with the African Miocene pecoran Propalaeoryx and with giraffoids. On the other hand, dromomerycids are closely related to cervids. We define a clade Giraffomorpha that includes palaeomerycids and giraffids, and propose an emended diagnosis of the Palaeomerycidae based on cranial and postcranial characters, including several features of the cranium not described so far. We also define the Palaeomerycidae as the least inclusive clade of pecorans containing Triceromeryx and Ampelomeryx. Finally, we reassess the taxonomy of several palaeomerycid taxa.", "keyphrases": ["ruminant", "giraffomorpha", "palaeomerycidae", "large clade"]}
{"id": "10.1029/2018PA003375", "title": "Early Eocene Thermal Maximum 3: Biotic Response at Walvis Ridge (SE Atlantic Ocean)", "abstract": "We combine stable isotope, calcareous nannoplankton, and benthic foraminiferal records for Ocean Drilling Program Sites 1262 (paleodepth ~3,500 m) and 1263 (paleodepth ~1,500 m) on Walvis Ridge (SE Atlantic), to document the marine biotic response to Eocene Thermal Maximum 3, in the early part of the Early Eocene Climate Optimum, ~3.1 Myr after the Paleocene/Eocene Thermal Maximum. Bottom water warming may have decreased the vertical thermal gradient at both sites, but more at Site 1263 than at Site 1262. Floral and faunal changes were more muted at Site 1262 than at shallower Site 1263, indicating that carbonate dissolution was not the most important cause of biotic effects. Assemblage changes were more pronounced in benthos than in plankton. Calcareous nannofossils underwent minor ecological changes, possibly related to the presence of warmer waters, especially at Site 1263, and dissolution\u2010resistant taxa increased in abundance. Benthic foraminiferal diversity decreased at both sites, but benthic foraminiferal accumulation rates declined dramatically at Site 1263, remaining stable at Site 1262. Ocean circulation may have changed during ETM3, resulting in the presence of a warmer (intermediate) water mass at Site 1263. More pronounced warming may have caused enhanced remineralization of organic matter, so less food reached the benthos. The biotic response to the X\u2010event was less pronounced than that to earlier and more severe hyperthermal events, the Paleocene/Eocene Thermal Maximum and Eocene Thermal Maximum 2. The extent of the biotic response reflects the severity of the environmental disturbance but varies by location (e.g., paleodepth on Walvis Ridge).", "keyphrases": ["eocene thermal maximum", "biotic response", "walvis ridge", "foraminiferal record"]}
{"id": "10.1002/2016GC006333", "title": "Increased precipitation and weathering across the Paleocene\u2010Eocene Thermal Maximum in central China", "abstract": "Global warming during the Paleocene\u2010Eocene Thermal Maximum (PETM) \u223c55.5 million years ago (Ma) was associated with a massive release of carbon to the ocean\u2010atmosphere system, as evidenced by a prominent negative carbon isotope excursion (CIE) and widespread dissolution of marine carbonates. The paleohydrologic response to the PETM warming has been studied worldwide; however, relevant records of environmental perturbation in Asia are lacking so far. Here we extend the record of this event in central China, a subtropical paleosetting, through geochemical and mineralogical analyses of lacustrine sediments. Geochemical indicators of authigenic carbonates\u2014including molar Mg/Ca and Sr/Ca ratios\u2014suggest an overall increased precipitation across the PETM, compatible with the disappearance of authigenic dolomite and the appearance of kaolinite in the strata. The relatively humid conditions persisted long after the carbon\u2010cycle perturbation had stopped, implying that the transient hyper\u2010greenhouse warming might have forced the regional climate system into a new climate state that was not easily reversed. Additionally, a gradual increase in chemical index of alteration (CIA) and the appearance of kaolinite are associated with the PETM, indicating an intensified silicate weathering and pedogenesis in the watershed in response to warmer and more humid climate. Our results corroborate the theory that an accelerated continental chemical weathering served as a negative feedback to sequester carbon and lower the atmospheric greenhouse\u2010gas levels during the PETM.", "keyphrases": ["precipitation", "paleocene\u2010eocene thermal maximum", "central china", "kaolinite"]}
{"id": "10.1126/science.208.4448.1095", "title": "Extraterrestrial Cause for the Cretaceous-Tertiary Extinction", "abstract": "Platinum metals are depleted in the earth's crust relative to their cosmic abundance; concentrations of these elements in deep-sea sediments may thus indicate influxes of extraterrestrial material. Deep-sea limestones exposed in Italy, Denmark, and New Zealand show iridium increases of about 30, 160, and 20 times, respectively, above the background level at precisely the time of the Cretaceous-Tertiary extinctions, 65 million years ago. Reasons are given to indicate that this iridium is of extraterrestrial origin, but did not come from a nearby supernova. A hypothesis is suggested which accounts for the extinctions and the iridium observations. Impact of a large earth-crossing asteroid would inject about 60 times the object's mass into the atmosphere as pulverized rock; a fraction of this dust would stay in the stratosphere for several years and be distributed worldwide. The resulting darkness would suppress photosynthesis, and the expected biological consequences match quite closely the extinctions observed in the paleontological record. One prediction of this hypothesis has been verified: the chemical composition of the boundary clay, which is thought to come from the stratospheric dust, is markedly different from that of clay mixed with the Cretaceous and Tertiary limestones, which are chemically similar to each other. Four different independent estimates of the diameter of the asteroid give values that lie in the range 10 \ufffd 4 kilometers.", "keyphrases": ["cause", "cretaceous-tertiary extinction", "asteroid", "mass extinction", "bolide impact"]}
{"id": "paleo.007628", "title": "A quantitative evaluation of evolutionary patterns in opercle bone shape in Saurichthys (Actinopterygii: Saurichthyidae)", "abstract": "Despite an impressive radiation of more than 30 species in the wake of the end\u2010Permian mass extinction, the taxonomic study of Saurichthys has suffered from a lack of universally diagnostic features and a lack of tested quantitative schemes that can be applied to analyse interspecific morphological differences. In this study, we provide an initial quantitative framework for morphological evolution in Saurichthys by focusing on a single bone, the opercle and exploring patterns of interspecific variability in shape using outline\u2010based geometric morphometrics and linear measurements. For the six species examined, comprising 155 specimens and representatives from the Early, Middle and Late Triassic, our results indicate that interspecific shape differences largely reflect an anterior\u2013posterior dimension decrease (= craniocaudal direction) as the dorso\u2010ventral dimension remains similar. In contrast, intraspecific variability in shape is subtle and spread across the outline of the bone, such that counter\u2010acting dimension differences (increase/decrease) were found to occur along a single margin at oblique axes in several species. Our quantitative scheme, which is widely applicable to other groups, provides a useful description of the broad modes of opercle shape change that may help as a starting framework from which to develop character states for opercle morphology in future study.", "keyphrases": ["evolutionary pattern", "saurichthys", "morphometric", "specie flock"]}
{"id": "10.1111/j.1502-3931.2012.00315.x", "title": "Earliest ontogeny of Early Palaeozoic Craniiformea : compelling evidence for lecithotrophy", "abstract": "Popov, L.E., Bassett, M.G. & Holmer, L.E. 2012: Earliest ontogeny of Early Palaeozoic Craniiformea: compelling evidence for lecithotrophy. Lethaia, Vol. 45, pp. 566\u2013573. \n \n \n \nThe early ontogeny of Palaeozoic Craniiformea (Brachiopoda) remains controversial, with conflicting reports of evidence indicating lecithotrophic versus planktotrophic larval stages. Further compelling evidence for lecithotrophy in Palaeozoic craniiforms is described here. Newly obtained, well-preserved Silurian specimens of craniiforms, including Craniops (Craniopsida), and Lepidocrania? and Orthisocrania (Craniida) from Gotland and the St. Petersburg region, form the basis for this study. The new material demonstrates that the characters of shell structure and shell formation provide evidence of early differentiation of an adult dorsal mantle, and the presence of a distinctive primary layer with a characteristic lath-like pattern indicates that these craniiforms underwent a lecithotrophic larval stage, more or less identical to that of living. \u25a1Novocrania. Brachiopoda, Craniiformea, ontogeny, phylogeny, Early Palaeozoic.", "keyphrases": ["early palaeozoic craniiformea", "lecithotrophy", "early ontogeny"]}
{"id": "paleo.003072", "title": "Pneumaticity and soft-tissue reconstructions in the neck of diplodocid and dicraeosaurid sauropods", "abstract": "The axial soft-tissue system in the neck of Dicraeosauridae and Diplodocidae, including pneumatic diverticula, ligaments, and muscles, is reconstructed on the basis of phylogenetic and functional morphological comparisons with extant crocodylians and birds and compared with other soft-tissue reconstructions for sauropods. Bifurcation of the neural spines separated the paired supraspinal ligament into two sheets. A paired interspinal septum was attached to the cranial and caudal margins of the neural spines. The dorsal and the lateral portions of the cervical musculature must have been strongly segmented, whereas the laterocostal portion was divided with one myoseptum per vertebral segment. The hypaxial cervical muscle was most probably small and only poorly segmented. In Diplodocidae and Dicraeosauridae, the distribution of external pneumatic structures is similar, whereas only Diplodocidae possess intraosseous pneumatic structures. Supravertebral pneumatic diverticula are reconstructed for both groups, which, together with dorsal ligaments filled the gap between the metapophyses of bifurcate neural spines. Comparisons between the vertebrae of juvenile and adult diplodocids strongly indicate that pneumatisation proceeded from the supramedullary diverticula into the neural arch and the neural spine. The regular branching pattern of the pneumatic cavities as well as the vertical I-beam construction of the vertebral corpora is interpreted as a consequence of the biomechanical constraints of the vertebral corpora in diplodocids. These reconstructions form the ground for functional morphological considerations in Diplodocidae and Dicraeosauridae while addressing the possible mechanical consequences of pneumatic structures for the integrity of the support system of the neck.", "keyphrases": ["sauropod", "pneumatic diverticula", "vertebrae", "pneumaticity"]}
{"id": "paleo.005447", "title": "Revisiting the molluscan fauna from the Cambrian (Series 2, stages 3\u20134) Xinji Formation of North China", "abstract": "A diverse group of molluscs from the Cambrian Series 2, Stages 3\u20134 Xinji Formation of the North China Block (NCB) is described, based on more than 4500 specimens from three well\u2010studied sections in Shaanxi and Henan provinces, along the southern and southwestern margin of the NCB. Twenty molluscan species are identified, including one bivalve, three stem group gastropods, and 16 additional helcionelloids. Among these, six helcionelloid species are reported from the NCB for the first time, and one new species, Parailsanella luonanensis sp. nov. is proposed. This diverse molluscan fauna shares a large number of species with contemporaneous faunas of South Australia (15), Antarctica (7), Laurentia (6), Siberia (3) and South China (1). Faunal similarities are even greater on a generic level. The striking similarities of the molluscan faunas of North China, South Australia and Antarctica strongly support the hypothesis that the NCB was situated close to Eastern Gondwana, most likely close to South Australia in the Cambrian Epoch 2. In addition, well\u2010preserved shell attachment muscle scars were observed in the helcionelloid Figurina figurina, with two pairs of symmetrical, continuous, band\u2010like muscle scars, which are obviously different from the musculature of both gastropods and monoplacophorans. Because of this unique musculature, these characteristic Cambrian cap\u2010like molluscs are assigned to the Helcionelloida rather than to the Gastropoda or Monoplacophora.", "keyphrases": ["north china", "mollusc", "cambrian series"]}
{"id": "paleo.006114", "title": "Atolchelys lepida, a new side-necked turtle from the Early Cretaceous of Brazil and the age of crown Pleurodira", "abstract": "We report a new pleurodiran turtle from the Barremian Morro do Chaves Formation, Sergipe-Alagoas Basin, Brazil. We tested the phylogenetic position of Atolchelys lepida gen. et sp. nov. by including it in a comprehensive cladistic analysis of pleurodires. The new species is a basal member of Bothremydidae and simultaneously the oldest unambiguous crown Pleurodira. The biogeographic and chronostratigraphic significance of the finding has implications for the calibration of molecular clocks studies by pushing back the minimum age of crown Pleurodira by more than 12 Ma (ca 125 Ma). The reanalysis of Pelomedusoides relationships provides evidence that the early evolution and relationships among the main lineages of side-necked turtles can be explained, at least partially, by a sequence of vicariance events.", "keyphrases": ["turtle", "early cretaceous", "crown pleurodira", "phylogenetic position"]}
{"id": "paleo.000954", "title": "Proteomic method to extract, concentrate, digest and enrich peptides from fossils with coloured (humic) substances for mass spectrometry analyses", "abstract": "Humic substances are breakdown products of decaying organic matter that co-extract with proteins from fossils. These substances are difficult to separate from proteins in solution and interfere with analyses of fossil proteomes. We introduce a method combining multiple recent advances in extraction protocols to both concentrate proteins from fossil specimens with high humic content and remove humics, producing clean samples easily analysed by mass spectrometry (MS). This method includes: (i) a non-demineralizing extraction buffer that eliminates protein loss during the demineralization step in routine methods; (ii) filter-aided sample preparation (FASP) of peptides, which concentrates and digests extracts in one filter, allowing the separation of large humics after digestion; (iii) centrifugal stage tipping, which further clarifies and concentrates samples in a uniform process performed simultaneously on multiple samples. We apply this method to a moa fossil (approx. 800\u20131000 years) dark with humic content, generating colourless samples and enabling the detection of more proteins with greater sequence coverage than previous MS analyses on this same specimen. This workflow allows analyses of low-abundance proteins in fossils containing humics and thus may widen the range of extinct organisms and regions of their proteomes we can explore with MS.", "keyphrases": ["humic", "substance", "mass spectrometry", "protein"]}
{"id": "10.1073/pnas.1304661110", "title": "Phylogeny and tempo of diversification in the superradiation of spiny-rayed fishes", "abstract": "Spiny-rayed fishes, or acanthomorphs, comprise nearly one-third of all living vertebrates. Despite their dominant role in aquatic ecosystems, the evolutionary history and tempo of acanthomorph diversification is poorly understood. We investigate the pattern of lineage diversification in acanthomorphs by using a well-resolved time-calibrated phylogeny inferred from a nuclear gene supermatrix that includes 520 acanthomorph species and 37 fossil age constraints. This phylogeny provides resolution for what has been classically referred to as the \u201cbush at the top\u201d of the teleost tree, and indicates acanthomorphs originated in the Early Cretaceous. Paleontological evidence suggests acanthomorphs exhibit a pulse of morphological diversification following the end Cretaceous mass extinction; however, the role of this event on the accumulation of living acanthomorph diversity remains unclear. Lineage diversification rates through time exhibit no shifts associated with the end Cretaceous mass extinction, but there is a global decrease in lineage diversification rates 50 Ma that occurs during a period when morphological disparity among fossil acanthomorphs increases sharply. Analysis of clade-specific shifts in diversification rates reveal that the hyperdiversity of living acanthomorphs is highlighted by several rapidly radiating lineages including tunas, gobies, blennies, snailfishes, and Afro-American cichlids. These lineages with high diversification rates are not associated with a single habitat type, such as coral reefs, indicating there is no single explanation for the success of acanthomorphs, as exceptional bouts of diversification have occurred across a wide array of marine and freshwater habitats.", "keyphrases": ["spiny-rayed fish", "living acanthomorph", "reef", "phylogeny"]}
{"id": "10.1111/j.1463-6409.2005.00198.x", "title": "Microanatomy of the radius and lifestyle in amniotes (Vertebrata, Tetrapoda)", "abstract": "Radial cross\u2010sections of 49 species of extant and two species of extinct amniotes of known lifestyle have been studied in order to assess the relationship between lifestyle (aquatic, amphibious or terrestrial) and bone microanatomy. Most compactness profile and body size parameters exhibit a phylogenetic signal; therefore, classical statistical tests should not be used. Permutational multiple linear regressions show an ecological signal in most compactness profile parameters and in the cross\u2010section maximal diameter. A linear discriminant analysis is performed with these parameters to distinguish the various lifestyles. The discriminant function based on taxa of known lifestyle is used to infer the lifestyle of three extinct amniotes: the early nothosaur Pachypleurosaurus (amphibious), the therapsid Lystrosaurus (amphibious) and the synapsid Ophiacodon (aquatic). These predictions are congruent with classical palaeoecological interpretations. This model may be very useful when attempting to infer the ancestral lifestyle of amniotes and other early limbed vertebrates.", "keyphrases": ["lifestyle", "amniote", "ecological signal", "microanatomy"]}
{"id": "paleo.005974", "title": "Soft Anatomy of the Early Cambrian Arthropod Isoxys curvirostratus from the Chengjiang Biota of South China with a Discussion on the Origination of Great Appendages", "abstract": "An updated reconstruction of the body plan, functional morphology and lifestyle of the arthropod Isoxys curvirostratus is proposed, based on new fossil specimens with preserved soft anatomy found in several localities of the Lower Cambrian Chengjiang Lagerst\u00e4tte. The animal was 2\u20134 cm long and mostly encased in a single carapace which is folded dorsally without an articulated hinge. The attachment of the body to the exoskeleton was probably cephalic and apparently lacked any well-developed adductor muscle system. Large stalked eyes with the eye sphere consisting of two layers (as corneal and rhabdomeric structures) protrude beyond the anterior margin of the carapace. This feature, together with a pair of frontal appendages with five podomeres that each bear a stout spiny outgrowth, suggests it was raptorial. The following 14 pairs of limbs are biramous and uniform in shape. The slim endopod is composed of more than 7 podomeres without terminal claw and the paddle shaped exopod is fringed with at least 17 imbricated gill lamellae along its posterior margin. The design of exopod in association with the inner vascular (respiratory) surface of the carapace indicates I. curvirostratus was an active swimmer. Morphological comparisons demonstrate that species of Isoxys were diverse in feeding habits and occupied a very broad morphospace, i.e., carapace bivalved or a single shield, the pre-oral limbs antenniform or modified into great appendages, the succeeding endopods slim or stout. This casts doubt on the current taxonomy that assigns all species to a single genus, and on any presumed lifestyle of Isoxys extrapolated to the generic level. Finally, since I. curvirostratus and I. acutangulus carry a pair of great appendages, Isoxys has recently been placed into the great appendage arthropods. Such placement might be inadequate because the homology of the great appendages can not be established.", "keyphrases": ["arthropod isoxys curvirostratus", "chengjiang biota", "appendage", "endopod"]}
{"id": "10.1144/0016-76492009-178", "title": "Exceptionally preserved ostracodes from a Middle Miocene palaeolake, California, USA", "abstract": "Abstract: Exceptionally well-preserved specimens of a new cypridid ostracode (Crustacea), Raepula ira sp. nov., are described from palaeolake sediments of the Middle Miocene Barstow Formation of the Mud Hills, southern California. This is only the second occurrence of exceptionally preserved ostracodes from the Miocene. Based on ages obtained from associated volcanic tuffs the palaeolake sediments were deposited between 16.3 and 15.8 Ma. The ostracodes form one element of a diverse lake community dominated by fairy shrimps, copepods, diatoms, larvae of diving beetles, flies and mosquitoes, and body fossils and ephippia of branchiopods and anomopods. The ostracodes are preserved three dimensionally with their soft anatomy replicated in microcrystalline silica. Submicron-scale details such as sensory setae are preserved, surpassing the resolution of most other ostracode-bearing lagerst\u00e4tten and allowing their biology to be compared with extant taxa. Supplementary material: Red\u2013blue anaglyphs of the exceptionally preserved ostracodes are available at http://www.geolsoc.org.uk/SUP18407.", "keyphrases": ["ostracode", "california", "mud hills"]}
{"id": "10.1111/pala.12110", "title": "The monophyly of Euparkeriidae (Reptilia: Archosauriformes) and the origins of Archosauria: a revision of Dorosuchus neoetus from the Mid\u2010Triassic of Russia", "abstract": "Euparkeria capensis is resolved as the sister taxon to Archosauria in many cladistic phylogenies and provides a key outgroup which may approximate the ancestral archosaur morphology. Several other taxa have been referred to the family Euparkeriidae, but the monophyly of this taxon remains doubtful and largely untested. To test this monophyly, the archosauriform and putative euparkeriid Dorosuchus neoetus from the Mid\u2010Triassic of Russia is re\u2010examined in the light of recent work on the evolution of stem archosaurs. Dorosuchus neoetus is found to possess a number of morphological features that place it close to Archosauria, including a sigmoidal femur with a clear attachment region for the m. caudifemoralis musculature, but no unambiguous archosaurian apomorphies. Dorosuchus neoetus is included for the first time in a numerical cladistic analysis and is recovered as the sole sister taxon to Archosauria + Phytosauria. A monophyletic Euparkeriidae including D. neoetus and E. capensis is slightly less parsimonious. In addition, a mandible and pterygoid that were previously referred to D. neoetus subsequent to the original description of the species are also included separately within the phylogenetic analysis and are recovered within Archosauria, possibly raising questions as to their correct taxonomic referral. However, this phylogenetic placement is based primarily on the absence of palatal teeth, but the presence or absence of palatal teeth exhibits considerable homoplasy within Archosauriformes. Based on other aspects of their morphology, we do not reject the referral of these elements to D. neoetus.", "keyphrases": ["monophyly", "euparkeriidae", "archosauriformes"]}
{"id": "paleo.004702", "title": "Telltale eyes: the lateral visual systems of Rhenish Lower Devonian eurypterids (Arthropoda, Chelicerata) and their palaeobiological implications", "abstract": "The compound eyes of three taxa of Rhenish Lower Devonian eurypterids are examined and compared with those known from other eurypterids and the extant horseshoe crab Limulus polyphemus. The lateral eyes of the small species Rhenopterus diensti, a phylogenetically basal representative of the stylonurine clade, are characterized by a comparatively low number of lenses and high interommatidial angle \u0394\u03c6 (2.8\u00b0). The comparatively limited visual capacities of R. diensti are more similar to L. polyphemus than to its closer relatives of the eurypterine clade and perhaps this reflects a progression of lateral eye structure in the evolution of eurypterids as a whole. The number of eye facets in Adelophthalmus sievertsi is higher than that in the supposed ambush predator Acutiramus cummingsi, but lower than that in other \u2018swimming\u2019 eurypterids (Eurypterina). Due to poor preservation, no other eye parameters could be analysed in this species, but further morphological attributes and geographical distribution designate the mid\u2010sized A. sievertsi as an able swimmer. A low interommatidial angle \u0394\u03c6 of less than 1\u00b0 confirms that the visual capacities of Jaekelopterus rhenaniae are in line with an interpretation of this giant species as an active high\u2010level predator. The inferred lifestyles of adult individuals of these three, co\u2010occurring Rhenish eurypterids indicate niche differentiation avoiding to some degree the competition for food in their marginal marine to delta plain transitional habitats.", "keyphrases": ["eye", "niche differentiation", "food"]}
{"id": "10.1002/oa.1182", "title": "A \u2018new\u2019 palaeolithic dog from central Europe", "abstract": "Kesslerloch Cave in Switzerland is one of the major Magdalenian sites in Central Europe. During a recent reanalysis of the faunal remains, we identified a cranial fragment and teeth of the domestic dog. The large maxillar fragment was directly dated to 12.225\u00b145 bp (KIA-33350) or c. 14.100-14.600 BP. The finds are metrically well below the natural variability of wolves from both Palaeolithic and recent times and even show slight morphological differences to the wild wolves from the site. We argue that the maxilla fragment must now be considered the earliest indisputable directly dated evidence of a domestic dog. Copyright \u00a9 2010 John Wiley & Sons, Ltd.", "keyphrases": ["dog", "central europe", "wolf"]}
{"id": "10.1163/156854297X00175", "title": "Flightlessness and Long Bone Allometry in Palaeognathiformes and Sphenisciformes", "abstract": "Palaeognathiformes and Sphenisciformes are the only two major taxa that have lost the capacity for flying. Nevertheless, the consequences of this flightlessness are completely different. While Palaeognathiformes are all running birds, Sphenisciformes are adapted to swimming. To study the morphology of leg and wing bones, length, sagittal and transverse diameters and second moment of area of humerus, ulna, radius, femur, tibiotarsus and tarsometatarsus were measured. Thirty-three specimens from fourteen species of Palaeognathiformes and eleven specimens from seven species of Sphenisciformes were studied. Several non-flying species from other avian orders were also considered. Regressions of all these parameters were calculated with body mass as the independent variable. For each bone, the ratio sagittal diameter/transverse diameter was also calculated. Most of the correlations are significantly different from the isometric condition. From a mechanical point of view, the most interesting result is that the second moment of area of the leg long bones always scales with strong positive allometry, whereas in the case of the wing long bones, the scaling shows high negative allometry. Biometrically, Sphenisciformes display a constant wing long bone morphology, with transverse diameters much larger than sagittal. In contrast, Palaeognathiformes present a highly variable morphology of the wing bones, affecting length and diameters.", "keyphrases": ["allometry", "palaeognathiformes", "sphenisciforme", "body mass", "flightlessness"]}
{"id": "10.1080/14772019.2021.1883756", "title": "Redescription of the skull of Hezhengia bohlini (Artiodactyla, Mammalia) and a reassessment of the systematics of the Chinese late Miocene \u2018ovibovines\u2019", "abstract": "Hezhengia is the most recently named \u2018ovibovine\u2019 genus, established by Qiu et al. (2000) based on a brief description of several skulls from Hezheng County, Linxia Prefecture, without attempting to provide a phylogenetic analysis with the other Chinese \u2018ovibovines\u2019, including Tsaidamotherium, Shaanxispira, Lantiantragus, Urmiatherium and Plesiaddax. Since then more than 100 well-preserved skulls have been discovered from the Linxia Basin. Most of the late Miocene \u2018ovibovines\u2019 have a highly specialized horn apparatus, and their inter-relationships and relationships to the extant Ovibos remain enigmatic. In this study, we provide detailed descriptions of H. bohlini skulls and mandibles, compared with the other Chinese late Miocene \u2018ovibovines\u2019. Two previously described upper jaws (?Plesiaddax minor) from Fugu County in north-western China are referred to a second species of Hezhengia, H. minor (Bohlin, 1935a). We perform a cladistic analysis using 110 morphological characters of skull, teeth and horn core, including all the Chinese late Miocene \u2018ovibovine\u2019 genera with relatively complete skulls, the middle Miocene fossil bovid Turcocerus, and 13 extant bovids. An analysis focused on the target fossil taxa is also performed with minimally necessary extant bovids. The phylogenetic analyses indicate that the Chinese late Miocene \u2018ovibovines\u2019 are paraphyletic offshoots of the same clade including Turcocerus and the extant capines, and none of them is closely related to Ovibos. We tentatively divided them into three groups, referring Hezhengia, Plesiaddax and Urmiatherium to the tribe Urmiatheriini, finding Shaanxispira and Lantiantragus as closely related, and Tsaidamotherium probably a distant clade.", "keyphrases": ["skull", "chinese late miocene", "ovibovine", "linxia basin"]}
{"id": "10.1073/pnas.1222843110", "title": "Time-dependent climate sensitivity and the legacy of anthropogenic greenhouse gas emissions", "abstract": "Climate sensitivity measures the response of Earth\u2019s surface temperature to changes in forcing. The response depends on various climate processes that feed back on the initial forcing on different timescales. Understanding climate sensitivity is fundamental to reconstructing Earth\u2019s climatic history as well as predicting future climate change. On timescales shorter than centuries, only fast climate feedbacks including water vapor, lapse rate, clouds, and snow/sea ice albedo are usually considered. However, on timescales longer than millennia, the generally higher Earth system sensitivity becomes relevant, including changes in ice sheets, vegetation, ocean circulation, biogeochemical cycling, etc. Here, I introduce the time-dependent climate sensitivity, which unifies fast-feedback and Earth system sensitivity. I show that warming projections, which include a time-dependent climate sensitivity, exhibit an enhanced feedback between surface warming and ocean CO2 solubility, which in turn leads to higher atmospheric CO2 levels and further warming. Compared with earlier studies, my results predict a much longer lifetime of human-induced future warming (23,000\u2013165,000 y), which increases the likelihood of large ice sheet melting and major sea level rise. The main point regarding the legacy of anthropogenic greenhouse gas emissions is that, even if the fast-feedback sensitivity is no more than 3 K per CO2 doubling, there will likely be additional long-term warming from slow climate feedbacks. Time-dependent climate sensitivity also helps explaining intense and prolonged warming in response to massive carbon release as documented for past events such as the Paleocene\u2013Eocene Thermal Maximum.", "keyphrases": ["legacy", "greenhouse gas emission", "time-dependent climate sensitivity"]}
{"id": "paleo.007680", "title": "The Dentition of Megalosaurid Theropods", "abstract": "Theropod teeth are particularly abundant in the fossil record and frequently reported in the literature. Yet, the dentition of many theropods has not been described comprehensively, omitting details on the denticle shape, crown ornamentations and enamel texture. This paucity of information has been particularly striking in basal clades, thus making identification of isolated teeth difficult, and taxonomic assignments uncertain. We here provide a detailed description of the dentition of Megalosauridae, and a comparison to and distinction from superficially similar teeth of all major theropod clades. Megalosaurid dinosaurs are characterized by a mesial carina facing mesiolabially in mesial teeth, centrally positioned carinae on both mesial and lateral crowns, a mesial carina terminating above the cervix, and short to well-developed interdenticular sulci between distal denticles. A discriminant analysis performed on a dataset of numerical data collected on the teeth of 62 theropod taxa reveals that megalosaurid teeth are hardly distinguishable from other theropod clades with ziphodont dentition. This study highlights the importance of detailing anatomical descriptions and providing additional morphometric data on teeth with the purpose of helping to identify isolated theropod teeth in the future.", "keyphrases": ["dentition", "theropod", "carinae", "tooth"]}
{"id": "10.1111/2041-210X.12987", "title": "How should we estimate diversity in the fossil record? Testing richness estimators using sampling\u2010standardised discovery curves", "abstract": "To infer genuine patterns of biodiversity change in the fossil record, we must be able to accurately estimate relative differences in numbers of taxa (richness) despite considerable variation in sampling between time intervals. Popular subsampling (=interpolation) methods aim to standardise diversity samples by rarefying the data to equal sample size or equal sample completeness (=coverage). Standardising by sample size is misleading because it compresses richness ratios, thereby flattening diversity curves. However, standardising by coverage reconstructs relative richness ratios with high accuracy. Asymptotic richness extrapolators are widely used in ecology, but rarely applied to fossil data. However, a recently developed parametric extrapolation method, TRiPS (True Richness estimation using Poisson Sampling), specifically aims to estimate the true richness of fossil assemblages. Here, we examine the suitability of a range of richness estimators (both interpolators and extrapolators) for fossil datasets, using simulations and a novel method for comparing the performance of richness estimators with empirical data. We constructed sampling\u2010standardised discovery curves (SSDCs) for two datasets, each spanning 150 years of palaeontological research: Mesozoic dinosaurs at global scale, and Mesozoic\u2013early Cenozoic tetrapods from North America. These approaches reveal how each richness estimator responds to both simulated best\u2010case and empirical real\u2010world accumulation of fossil occurrences. We find that extrapolators can only truly standardise diversity data once sampling is sufficient for richness estimates to have asymptoted. Below this point, directly comparing extrapolated estimates derived from samples of different sizes may not accurately reconstruct relative richness ratios. When abundance distributions are not perfectly flat and sampling is moderate to good, but not perfect, TRiPS does not extrapolate, because it overestimates binomial sampling probabilities. Coverage\u2010based interpolators, by contrast, generally yield more stable subsampled diversity estimates, even in the face of dramatic increases in face\u2010value counts of species richness. Richness estimators that standardise by coverage are among the best currently available methods for reconstructing deep\u2010time biodiversity patterns. However, we recommend the use of sampling\u2010standardised discovery curves to understand how biased reporting of fossil occurrences may affect sampling\u2010standardised diversity estimates.", "keyphrases": ["richness estimator", "discovery curve", "sample size", "fossil data", "extent"]}
{"id": "paleo.010914", "title": "Evolutionary and Biological Implications of Dental Mesial Drift in Rodents: The Case of the Ctenodactylidae (Rodentia, Mammalia)", "abstract": "Dental characters are importantly used for reconstructing the evolutionary history of mammals, because teeth represent the most abundant material available for the fossil species. However, the characteristics of dental renewal are presently poorly used, probably because dental formulae are frequently not properly established, whereas they could be of high interest for evolutionary and developmental issues. One of the oldest rodent families, the Ctenodactylidae, is intriguing in having longstanding disputed dental formulae. Here, we investigated 70 skulls among all extant ctenodactylid genera (Ctenodactylus, Felovia, Massoutiera and Pectinator) by using X-ray conventional and synchrotron microtomography in order to solve and discuss these dental issues. Our study clearly indicates that Massoutiera, Felovia and Ctenodactylus differ from Pectinator not only by a more derived dentition, but also by a more derived eruptive sequence. In addition to molars, their dentition only includes the fourth deciduous premolars, and no longer bears permanent premolars, conversely to Pectinator. Moreover, we found that these premolars are lost during adulthood, because of mesial drift of molars. Mesial drift is a striking mechanism involving migration of teeth allowed by both bone remodeling and dental resorption. This dental innovation is to date poorly known in rodents, since it is only the second report described. Interestingly, we noted that dental drift in rodents is always associated with high-crowned teeth favoring molar size enlargement. It can thus represent another adaptation to withstand high wear, inasmuch as these rodents inhabit desert environments where dust is abundant. A more accurate study of mesial drift in rodents would be very promising from evolutionary, biological and orthodontic points of view.", "keyphrases": ["mesial drift", "rodent", "ctenodactylidae", "molar"]}
{"id": "paleo.006223", "title": "The oldest Gondwanan cephalopod mandibles (Hangenberg Black Shale, Late Devonian) and the mid\u2010Palaeozoic rise of jaws", "abstract": "It is widely accepted that the effects of global sea\u2010level changes at the transition from the Devonian to the Carboniferous are recorded in deposits on the shelf of northern Gondwana. These latest Devonian strata had been thought to be poor in fossils due to the Hangenberg mass extinction. In the Ma'der (eastern Anti\u2010Atlas), however, the Hangenberg Black Shale claystones (latest Famennian) are rich in exceptionally preserved fossils displaying the remains of non\u2010mineralized structures. The diversity in animal species of these strata is, however, low. Remarkably, the organic\u2010rich claystones have yielded abundant remains of Ammonoidea preserved with their jaws, both in situ and isolated. This is important because previously, the jaws of only one of the main Devonian ammonoid clades had been found (Frasnian Gephuroceratina). Here, we describe four types of jaws of which two could be assigned confidently to the Order Clymeniida and to the Suborder Tornoceratina. These findings imply that chitinous normal\u2010type jaws were likely to have already been present at the origin of the whole clade Ammonoidea, i.e. in the early Emsian (or earlier). Vertebrate jaws evolved prior to the Early Devonian origin of ammonoids. The temporal succession of evolutionary events suggests that it could have been the indirect positive selection pressure towards strong (and thus preservable) jaws since defensive structures of potential prey animals would otherwise have made them inaccessible to jawless predators in the course of the mid\u2010Palaeozoic marine revolution. In this respect, our findings reflect the macroecological changes that occurred in the Devonian. [Correction added on 28 July 2016 after first online publication: In the Abstract, the sentence \u201cVertebrate jaws probably \u2026 in the Early Devonian\u201d was amended]", "keyphrases": ["cephalopod", "hangenberg black shale", "late devonian", "jaw", "ammonoid clade"]}
{"id": "paleo.001877", "title": "New application of strontium isotopes reveals evidence of limited migratory behaviour in Late Cretaceous hadrosaurs", "abstract": "Dinosaur migration patterns are very difficult to determine, often relying solely on the geographical distribution of fossils. Unfortunately, it is generally not possible to determine if a fossil taxon's geographical distribution is the result of migration or simply a wide distribution. Whereas some attempts have been made to use isotopic systems to determine migratory patterns in dinosaurs, these methods have yet to achieve wider usage in the study of dinosaur ecology. Here, we have used strontium isotope ratios from fossil enamel to reconstruct the movements of an individual hadrosaur from Dinosaur Provincial Park in Alberta, Canada. Results from this study are consistent with a range or migratory pattern between Dinosaur Provincial Park and a contemporaneous locality in the South Saskatchewan River area, Alberta, Canada. This represents a minimum distance of approximately 80 km, which is consistent with migrations seen in modern elephants. These results suggest the continent-wide distribution of some hadrosaur species in the Late Cretaceous of North America is not the result of extremely long-range migratory behaviours.", "keyphrases": ["migratory behaviour", "hadrosaur", "north america"]}
{"id": "10.1017/S0094837300008915", "title": "Jaw geometry and molar morphology in marsupial carnivores: analysis of a constraint and its macroevolutionary consequences", "abstract": "In both jaw geometry and molar morphology, eutherian carnivores (order Carnivora) as a whole display greater diversity (plasticity in evolution from the primitive type) than marsupial carnivores (order Dasyurida). This is related to the difference in tooth replacement between the two taxa. In Carnivora, the permanent carnassial is preceded by a deciduous carnassial; the permanent tooth can erupt in its (geometrically) permanent position, and the post-carnassial molars are free to evolve for specialized functions or be reduced. In Dasyurida, there is relative molar progression, each erupting molar in turn functioning as a carnassial, and subsequently being pushed forwards in the jaw by the next erupting molar. Thus, all molars have carnassiform morphology, and none are free to develop for other functions. The greater plasticity of Carnivora has led to their adaptive zone being broader (as a group they are relatively more eurytopic than Dasyurida), which in turn has led to greater taxonomic diversity within Carnivora than Dasyurida. The resulting pattern from a macroevolutionary point of view is that, even in the absence of direct competition, Carnivora have had greater evolutionary \u201csuccess\u201d than Dasyurida.", "keyphrases": ["molar morphology", "marsupial carnivore", "jaw geometry"]}
{"id": "10.1206/3717.2", "title": "The Anatomy of Dryptosaurus aquilunguis (Dinosauria: Theropoda) and a Review of Its Tyrannosauroid Affinities", "abstract": "ABSTRACT Although among the first theropod dinosaurs known to science, and an iconic taxon in the history of dinosaur paleontology, the large carnivore Dryptosaurus aquilunguis from the Late Cretaceous of New Jersey remains poorly understood. Its anatomy has been described only in brief and its phylogenetic relationships have long been the subject of debate, although recent work proposes Dryptosaurus as a member of the tyrannosauroid clade. Here we present a thorough osteological description of the holotype of Dryptosaurus aquilunguis, supplemented with photographs of all the material, and provide extensive comparisons with other theropods, especially tyrannosauroids. In concert with recent phylogenetic analyses, our description confirms the tyrannosauroid affinities of Dryptosaurus and supports its placement as an \u201cintermediate\u201d taxon bracketed between small, basal forms (e.g., Guanlong, Dilong) and the derived, Late Cretaceous tyrannosaurids (e.g., Albertosaurus, Tyrannosaurus). We identify several autapomorphies of Dryptosaurus, including the combination of a reduced humerus and an enlarged hand. These forelimb proportions, which differ from the uniformly large arms of basal tyrannosauroids and uniformly atrophied arms of tyrannosaurids, suggest that forelimb reduction in tyrannosauroids may not have proceeded in a uniform fashion. Functionally, Dryptosaurus may have used both its skull and arms as weapons for prey acquisition and processing.", "keyphrases": ["anatomy", "dryptosaurus aquilunguis", "tyrannosauroid affinity", "late cretaceous", "holotype"]}
{"id": "10.1080/08912963.2019.1648451", "title": "A Middle Miocene (~14 Ma) vertebrate assemblage from Palasava, Rapar Taluka, Kutch (Kachchh) District, Gujarat State, western India", "abstract": "ABSTRACT The present article aims to record a recently discovered middle Miocene vertebrate assemblage (including marine and terrestrial mammals) from Palasava, Kutch (Kachchh) District, Gujarat State, western India. The faunal assemblage comprising fishes, chelonians, crocodiles, snakes, birds and mammals is significant in terms of palaeoecology, palaeoenvironment and biostratigraphy of the region and yields evidence concerning its biogeographic affinities linked to Neogene Eustatic history. Palasava fauna together with previously known Neogene (particularly Miocene) vertebrate assemblages from the Kutch region indicates the presence of a riverine-estuarine system(s) linked to the sea, i.e. the depositional centres were quite close to the sea. Furthermore, the Palasava vertebrate assemblage (recorded herein) points towards a prevalence of warm, humid/wet, tropical to sub-tropical environmental conditions. The terrestrial mammalian assemblage from Palasava represents at least seven families with six of the terrestrial mammalian taxa identified herein to the genus level, namely: Sanitherium, Sivameryx, Brachypotherium, Zygolophodon, Gomphotherium, and Deinotherium. The overall assemblage (including Zygolophodon and Deinotherium) is indicative of a Middle Miocene, 14 \u00b1 2 Ma (Langhian to Serravallian) age for the sedimentary succession at Palasava. Furthermore, a ~ 14 Ma age for the Palasava fauna indicates a correlation to regression cycle R5 in the Tagus Valley succession of Portugal.", "keyphrases": ["middle miocene", "brachypotherium", "zygolophodon"]}
{"id": "paleo.006613", "title": "Our past creates our present: a brief overview of racism and colonialism in Western paleontology", "abstract": "Abstract. As practitioners of a historical science, paleontologists and geoscientists are well versed in the idea that the ability to understand and to anticipate the future relies upon our collective knowledge of the past. Despite this understanding, the fundamental role that the history of paleontology and the geosciences plays in shaping the structure and culture of our disciplines is seldom recognized and therefore not acted upon sufficiently. Here, we present a brief review of the history of paleontology and geology in Western countries, with a particular focus on North America since the 1800s. Western paleontology and geology are intertwined with systematic practices of exclusion, oppression, and erasure that arose from their direct participation in the extraction of geological and biological resources at the expense of Black, Indigenous, and People of Color (BIPOC). Our collective failure to acknowledge this history hinders our ability to address these issues meaningfully and systemically in present-day educational, academic, and professional settings. By discussing these issues and suggesting some ways forward, we intend to promote a deeper reflection upon our collective history and a broader conversation surrounding racism, colonialism, and exclusion within our scientific communities. Ultimately, it is necessary to listen to members of the communities most impacted by these issues to create actionable steps forward while holding ourselves accountable for the past.", "keyphrases": ["past", "colonialism", "western paleontology", "country", "reflection"]}
{"id": "10.1126/science.1109004", "title": "Rapid Acidification of the Ocean During the Paleocene-Eocene Thermal Maximum", "abstract": "The Paleocene-Eocene thermal maximum (PETM) has been attributed to the rapid release of \u223c2000 \u00d7 109 metric tons of carbon in the form of methane. In theory, oxidation and ocean absorption of this carbon should have lowered deep-sea pH, thereby triggering a rapid (<10,000-year) shoaling of the calcite compensation depth (CCD), followed by gradual recovery. Here we present geochemical data from five new South Atlantic deep-sea sections that constrain the timing and extent of massive sea-floor carbonate dissolution coincident with the PETM. The sections, from between 2.7 and 4.8 kilometers water depth, are marked by a prominent clay layer, the character of which indicates that the CCD shoaled rapidly (<10,000 years) by more than 2 kilometers and recovered gradually (>100,000 years). These findings indicate that a large mass of carbon (\u00bb2000 \u00d7 109 metric tons of carbon) dissolved in the ocean at the Paleocene-Eocene boundary and that permanent sequestration of this carbon occurred through silicate weathering feedback.", "keyphrases": ["ocean", "paleocene-eocene thermal maximum", "methane", "global warming", "hyperthermal event"]}
{"id": "paleo.011480", "title": "Relaxed Molecular Clock Provides Evidence for Long-Distance Dispersal of Nothofagus (Southern Beech)", "abstract": "Nothofagus (southern beech), with an 80-million-year-old fossil record, has become iconic as a plant genus whose ancient Gondwanan relationships reach back into the Cretaceous era. Closely associated with Wegener's theory of \u201cKontinentaldrift\u201d, Nothofagus has been regarded as the \u201ckey genus in plant biogeography\u201d. This paradigm has the New Zealand species as passengers on a Moa's Ark that rafted away from other landmasses following the breakup of Gondwana. An alternative explanation for the current transoceanic distribution of species seems almost inconceivable given that Nothofagus seeds are generally thought to be poorly suited for dispersal across large distances or oceans. Here we test the Moa's Ark hypothesis using relaxed molecular clock methods in the analysis of a 7.2-kb fragment of the chloroplast genome. Our analyses provide the first unequivocal molecular clock evidence that, whilst some Nothofagus transoceanic distributions are consistent with vicariance, trans-Tasman Sea distributions can only be explained by long-distance dispersal. Thus, our analyses support the interpretation of an absence of Lophozonia and Fuscospora pollen types in the New Zealand Cretaceous fossil record as evidence for Tertiary dispersals of Nothofagus to New Zealand. Our findings contradict those from recent cladistic analyses of biogeographic data that have concluded transoceanic Nothofagus distributions can only be explained by vicariance events and subsequent extinction. They indicate that the biogeographic history of Nothofagus is more complex than envisaged under opposing polarised views expressed in the ongoing controversy over the relevance of dispersal and vicariance for explaining plant biodiversity. They provide motivation and justification for developing more complex hypotheses that seek to explain the origins of Southern Hemisphere biota.", "keyphrases": ["long-distance dispersal", "nothofagus", "southern beech", "new zealand", "vicariance"]}
{"id": "paleo.009917", "title": "Hominid butchers and biting crocodiles in the African Plio\u2013Pleistocene", "abstract": "Significance The idea that early Australopithecus shaped stone tools to butcher large mammals before the emergence of Homo around 2 million years ago has excited both primatologists and archaeologists. Such claims depend on interpreting modifications found on the surfaces of fossil bones. Recent experiments involving the feeding of mammal carcasses to modern crocodiles have revealed that equifinality\u2014the creation of similar products by different processes\u2014is more important than previously appreciated by zooarchaeologists. Application of these findings to Ethiopian fossils casts doubt on claims for the earliest large mammal butchery and indicates the need for reassessment of all Oldowan-associated bone assemblages to determine the degree to which equifinality compromises earlier interpretations of hominid subsistence activities and their role in human evolution. Zooarchaeologists have long relied on linear traces and pits found on the surfaces of ancient bones to infer ancient hominid behaviors such as slicing, chopping, and percussive actions during butchery of mammal carcasses. However, such claims about Plio\u2013Pleistocene hominids rely mostly on very small assemblages of bony remains. Furthermore, recent experiments on trampling animals and biting crocodiles have shown each to be capable of producing mimics of such marks. This equifinality\u2014the creation of similar products by different processes\u2014makes deciphering early archaeological bone assemblages difficult. Bone modifications among Ethiopian Plio\u2013Pleistocene hominid and faunal remains at Asa Issie, Maka, Hadar, and Bouri were reassessed in light of these findings. The results show that crocodiles were important modifiers of these bone assemblages. The relative roles of hominids, mammalian carnivores, and crocodiles in the formation of Oldowan zooarchaeological assemblages will only be accurately revealed by better bounding equifinality. Critical analysis within a consilience-based approach is identified as the pathway forward. More experimental studies and increased archaeological fieldwork aimed at generating adequate samples are now required.", "keyphrases": ["crocodile", "human evolution", "mammalian carnivore"]}
{"id": "paleo.006993", "title": "Insights into the Ecology and Evolutionary Success of Crocodilians Revealed through Bite-Force and Tooth-Pressure Experimentation", "abstract": "Background Crocodilians have dominated predatory niches at the water-land interface for over 85 million years. Like their ancestors, living species show substantial variation in their jaw proportions, dental form and body size. These differences are often assumed to reflect anatomical specialization related to feeding and niche occupation, but quantified data are scant. How these factors relate to biomechanical performance during feeding and their relevance to crocodilian evolutionary success are not known. Methodology/Principal Findings We measured adult bite forces and tooth pressures in all 23 extant crocodilian species and analyzed the results in ecological and phylogenetic contexts. We demonstrate that these reptiles generate the highest bite forces and tooth pressures known for any living animals. Bite forces strongly correlate with body size, and size changes are a major mechanism of feeding evolution in this group. Jaw shape demonstrates surprisingly little correlation to bite force and pressures. Bite forces can now be predicted in fossil crocodilians using the regression equations generated in this research. Conclusions/Significance Critical to crocodilian long-term success was the evolution of a high bite-force generating musculo-skeletal architecture. Once achieved, the relative force capacities of this system went essentially unmodified throughout subsequent diversification. Rampant changes in body size and concurrent changes in bite force served as a mechanism to allow access to differing prey types and sizes. Further access to the diversity of near-shore prey was gained primarily through changes in tooth pressure via the evolution of dental form and distributions of the teeth within the jaws. Rostral proportions changed substantially throughout crocodilian evolution, but not in correspondence with bite forces. The biomechanical and ecological ramifications of such changes need further examination.", "keyphrases": ["evolutionary success", "bite-force", "force", "tooth"]}
{"id": "10.1086/345841", "title": "Origination and Extinction through the Phanerozoic: A New Approach", "abstract": "Temporal patterns of origination and extinction are essential components of many paleontological studies, but it has been difficult to obtain accurate rate estimates because the observed record of first and last appearances is distorted by the incompleteness of the fossil record. Here I analyze observed first and last appearances of marine animal and microfossil genera in a way that explicitly takes incompleteness and its variation into consideration. This approach allows estimates of true rates of origination and extinction throughout the Phanerozoic. Substantial support is provided for the proposition that most rate peaks in the raw data are real in the sense that they do not arise as a consequence of temporal variability in the overall quality of the fossil record. Even though the existence of rate anomalies is supported, their timing is nevertheless open to question in many cases. If one assumes that rates of origination and extinction are constant through a given stratigraphic interval, then peaks in revised origination rates tend to be displaced backward and extinction peaks forward relative to the peaks in the raw data. If, however, one assumes a model of pulsed turnover, with true originations concentrated at lower interval boundaries and true extinctions concentrated at upper interval boundaries, the apparent timing of extinction peaks is largely reliable at face value. Thus, whereas rate anomalies may well be real, precisely when they occurred is a question that cannot be answered definitively without independent support for a model of smooth versus pulsed rate variation. The pattern of extinction, particularly the major events, is more faithfully represented in the fossil record than that of origination. There is a tendency for the major extinction events to occur during stages in which the quality of the record is relatively high and for recoveries from extinctions to occur when the record is less complete. These results imply that interpretations of origination and extinction history that depend only on the existence of rate anomalies are fairly robust, whereas interpretations of the timing of events and the temporal covariation between origination and extinction may require substantial revision.", "keyphrases": ["phanerozoic", "incompleteness", "face value", "origination"]}
{"id": "10.1073/pnas.0607824103", "title": "Confirmation of Romer's Gap as a low oxygen interval constraining the timing of initial arthropod and vertebrate terrestrialization", "abstract": "The first terrestrialization of species that evolved from previously aquatic taxa was a seminal event in evolutionary history. For vertebrates, one of the most important terrestrialized groups, this event was interrupted by a time interval known as Romer's Gap, for which, until recently, few fossils were known. Here, we argue that geochronologic range data of terrestrial arthropods show a pattern similar to that of vertebrates. Thus, Romer's Gap is real, occupied an interval from 360 million years before present (MYBP) to 345 MYBP, and occurred when environmental conditions were unfavorable for air-breathing, terrestrial animals. These model results suggest that atmospheric oxygen levels were the major driver of successful terrestrialization, and a low-oxygen interval accounts for Romer's Gap. Results also show that terrestrialization among members of arthropod and vertebrate clades occurred in two distinct phases. The first phase was a 65-million-year (My) interval from 425 to 360 MYBP, representing an earlier, prolonged event of complete arthropod terrestrialization of smaller-sized forms (425\u2013385 MYBP) and a subsequent, modest, and briefer event of incipient terrestrialization of larger-sized, aquatic vertebrates (385\u2013360 MYBP). The second phase began at 345 MYBP, characterized by numerous new terrestrial species emerging in both major clades. The first and second terrestrialization phases bracket Romer's Gap, which represents a depauperate spectrum of major arthropod and vertebrate taxa before a major Late Paleozoic colonization of terrestrial habitats.", "keyphrases": ["gap", "terrestrialization", "atmospheric oxygen level"]}
{"id": "paleo.006228", "title": "Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics", "abstract": "Vertebrates have evolved to gigantic sizes repeatedly over the past 250 Myr, reaching their extreme in today's baleen whales (Mysticeti). Hypotheses for the evolution of exceptionally large size in mysticetes range from niche partitioning to predator avoidance, but there has been no quantitative examination of body size evolutionary dynamics in this clade and it remains unclear when, why or how gigantism evolved. By fitting phylogenetic macroevolutionary models to a dataset consisting of living and extinct species, we show that mysticetes underwent a clade-wide shift in their mode of body size evolution during the Plio-Pleistocene. This transition, from Brownian motion-like dynamics to a trended random walk towards larger size, is temporally linked to the onset of seasonally intensified upwelling along coastal ecosystems. High prey densities resulting from wind-driven upwelling, rather than abundant resources alone, are the primary determinant of efficient foraging in extant mysticetes and Late Pliocene changes in ocean dynamics may have provided an ecological pathway to gigantism in multiple independent lineages.", "keyphrases": ["whale", "gigantism", "plio-pleistocene", "body size evolution", "wind-driven upwelling"]}
{"id": "paleo.003913", "title": "New Specimens of Nemegtomaia from the Baruungoyot and Nemegt Formations (Late Cretaceous) of Mongolia", "abstract": "Two new specimens of the oviraptorid theropod Nemegtomaia barsboldi from the Nemegt Basin of southern Mongolia are described. Specimen MPC-D 107/15 was collected from the upper beds of the Baruungoyot Formation (Campanian-Maastrichtian), and is a nest of eggs with the skeleton of the assumed parent of Nemegtomaia on top in brooding position. Much of the skeleton was damaged by colonies of dermestid coleopterans prior to its complete burial. However, diagnostic characters are recovered from the parts preserved, including the skull, partial forelimbs (including the left hand), legs, and distal portions of both feet. Nemegtomaia represents the fourth known genus of oviraptorid for which individuals have been found on nests of eggs. The second new specimen, MPC-D 107/16, was collected a few kilometers to the east in basal deposits of the Nemegt Formation, and includes both hands and femora of a smaller Nemegtomaia individual. The two formations and their diverse fossil assemblages have been considered to represent sequential time periods and different environments, but data presented here indicate partial overlap across the Baruungoyot-Nemegt transition. All other known oviraptorids from Mongolia and China are known exclusively from xeric or semi-arid environments. However, this study documents that Nemegtomaia is found in both arid/aeolian (Baruungoyot Formation) and more humid/fluvial (Nemegt Formation) facies.", "keyphrases": ["nemegtomaia", "mongolia", "baruungoyot formation"]}
{"id": "paleo.002244", "title": "Timing of global regression and microbial bloom linked with the Permian-Triassic boundary mass extinction: implications for driving mechanisms", "abstract": "New high-resolution U-Pb dates indicate a duration of 89 \u00b1 38 kyr for the Permian hiatus and of 14 \u00b1 57 kyr for the overlying Triassic microbial limestone in shallow water settings of the Nanpanjiang Basin, South China. The age and duration of the hiatus coincides with the Permian-Triassic boundary (PTB) and the extinction interval in the Meishan Global Stratotype Section and Point, and strongly supports a glacio-eustatic regression, which best explains the genesis of the worldwide hiatus straddling the PTB in shallow water records. In adjacent deep marine troughs, rates of sediment accumulation display a six-fold decrease across the PTB compatible with a dryer and cooler climate as indicated by terrestrial plants. Our model of the Permian-Triassic boundary mass extinction (PTBME) hinges on the synchronicity of the hiatus with the onset of the Siberian Traps volcanism. This early eruptive phase released sulfur-rich volatiles into the stratosphere, thus simultaneously eliciting a short-lived ice age responsible for the global regression and a brief but intense acidification. Abrupt cooling, shrunk habitats on shelves and acidification may all have synergistically triggered the PTBME. Subsequently, the build-up of volcanic CO 2 induced a transient cool climate whose early phase saw the deposition of the microbial limestone.\nSince the early days of stratigraphy, mass extinctions were noticed to coincide with major and global sea-level changes 1,2 that significantly alter extinction patterns and time-series of geochemical proxies. In the case of the Permian-Triassic boundary mass extinction (PTBME), the system boundary itself has been initially placed during a global eustatic regression 3 , but was subsequently placed during a global transgression 4 . The sea-level rise scenario naturally paved the way for a concomitant rise of the oxygen minimum zone as a kill mechanism, to which \"lethally\" hot sea-surface temperatures were recently added 5, 6 . With the exceptions of deep oceanic settings (e.g., Arrow Rocks, New Zealand 7 ; Mino Tamba Terrane, Japan 8,9 ), of few deep water shelves (e.g., Dongpan, South China 10 ) and of extremely rare shallow shelves (Musandam, United Arab Emirates 11 ), an overwhelming majority of globally distributed Permian-Triassic boundary (PTB) sections are affected by an unconformity separating the last Permian rocks from the first Triassic ones (e.g., Armenia 12 ; Canada 13 ; Pakistan 14 ; Norway 15 ; China 16 ). Intensively studied shallow water sections from South China follow this rule and the origin of this hiatus is intensively debated. Two competing mechanisms are frequently proposed: submarine dissolution through acidified waters 17 or subaerial erosion 18 . However, both mechanisms are not mutually exclusive and may conceivably have acted simultaneously 19 . In this respect, we emphasize here that climate-driven eustatic sea-level changes are commonly at the decamillennial timescale, an order of magnitude compatible with the duration of the world-wide regression that coincides with the PTB. The base of the Triassic in the equatorial shallow water sections is usually represented by the iconic microbial limestone 16 , which has been interpreted as the hallmark of ecosystem", "keyphrases": ["global regression", "boundary mass extinction", "ice age"]}
{"id": "paleo.007670", "title": "Not a limitless resource: ethics and guidelines for destructive sampling of archaeofaunal remains", "abstract": "With the advent of ancient DNA, as well as other methods such as isotope analysis, destructive sampling of archaeofaunal remains has increased much faster than the effort to collect and curate them. While there has been considerable discussion regarding the ethics of destructive sampling and analysis of human remains, this dialogue has not extended to archaeofaunal material. Here we address this gap and discuss the ethical challenges surrounding destructive sampling of materials from archaeofaunal collections. We suggest ways of mitigating the negative aspects of destructive sampling and present step-by-step guidelines aimed at relevant stakeholders, including scientists, holding institutions and scientific journals. Our suggestions are in most cases easily implemented without significant increases in project costs, but with clear long-term benefits in the preservation and use of zooarchaeological material.", "keyphrases": ["guideline", "destructive sampling", "archaeofaunal remain", "ancient dna", "isotope analysis"]}
{"id": "paleo.004839", "title": "PENNSYLVANIAN STRATIGRAPHY AND FUSULINIDS OF CENTRAL AND EASTERN IRAN", "abstract": "The Pennsylvanian succession of Central and Eastern Iran (Sardar Group) is studied in two key sections: Zaladu and Anarak. The Sardar Group (previously Sardar Formation) has been divided into two formations: the predominantly carbonate Ghaleh Formation and the predominantly siliciclastic or mixed carbonate-siliciclastic Absheni Formation. These two formations were earlier identified as Sardar 1 and Sardar 2 subformations. The Ghaleh Formation (formerly Sardar 1), of early Bashkirian age, is characterized by Eostaffella, Eostaffellina, Millerella, Plectostaffella, Semistaffella, primitive Pseudostaffella, and numerous archaediscids. The Absheni Formation (formerly Sardar 2) is upper lower Moscovian in age (late Vereian-early Kashirian) and is characterized by Profusulinella, Aljutovella, Neostaffella, Putrella, Moellerites, and Fusiella fusulinids. Poorly preserved upper Moscovian fusulinids (derived Fusiella, Fusulina, and Beedeina) occur at the top of this sequence. The hiatus between the Ghaleh and Absheni Formations corresponds to an interval from the upper Bashkirian, and probably to the lowermost Moscovian, and coincides with the replacement of predominantly carbonate sedimentation with mixed carbonate-siliciclastic sedimentation. The recently established late Gzhelian-Asselian Zaladu Formation unconformably overlies the Absheni Formation. The new data disagree with the previously proposed paleogeographic reconstruction of Central Iran and surrounding regions (including Iran-Afghanistan territory) during the Carboniferous-Early Permian. The foraminiferal assemblages from the Bashkirian-Moscovian sections of Alborz and Eastern Iran show a close resemblance in every respect. It is evident that these regions were located within a single basin connected with the basins of Taurus and Anatolia in the west and those of the Donets, Russian platform, and Urals in the north.", "keyphrases": ["eastern iran", "pennsylvanian succession", "sardar group", "palaeozoic sediment", "ordovician shirgesht formation"]}
{"id": "paleo.004140", "title": "Fossil evidence and stages of elongation of the Giraffa camelopardalis neck", "abstract": "Several evolutionary theories have been proposed to explain the adaptation of the long giraffe neck; however, few studies examine the fossil cervical vertebrae. We incorporate extinct giraffids, and the okapi and giraffe cervical vertebral specimens in a comprehensive analysis of the anatomy and elongation of the neck. We establish and evaluate 20 character states that relate to general, cranial and caudal vertebral lengthening, and calculate a length-to-width ratio to measure the relative slenderness of the vertebrae. Our sample includes cervical vertebrae (n=71) of 11 taxa representing all seven subfamilies. We also perform a computational comparison of the C3 of Samotherium and Giraffa camelopardalis, which demonstrates that cervical elongation occurs disproportionately along the cranial\u2013caudal vertebral axis. Using the morphological characters and calculated ratios, we propose stages in cervical lengthening, which are supported by the mathematical transformations using fossil and extant specimens. We find that cervical elongation is anisometric and unexpectedly precedes Giraffidae. Within the family, cranial vertebral elongation is the first lengthening stage observed followed by caudal vertebral elongation, which accounts for the extremely long neck of the giraffe.", "keyphrases": ["elongation", "neck", "giraffe"]}
{"id": "10.54103/2039-4942/18877", "title": "THE ENDEMIC MARINE FISH FAUNA FROM THE EASTERN PARATETHYS RECONSTRUCTED FROM OTOLITHS FROM THE MIOCENE (MIDDLE SARMATIAN S.L.; BESSARABIAN) OF JURKINE (KERCH PENINSULA, CRIMEA)", "abstract": "Reconstructing fossil bony fish faunas using otoliths is a well-established method that allows a diverse and dense record in time and space to be assembled. Here we report about a rich otolith-based fish fauna from the middle Sarmatian s.l. (middle Bessarabian) from Jurkine, Kerch Peninsula, Crimea. The study is based on more than 5,000 specimens constituting 36 different species, 24 of which are new and 2 remain in open nomenclature. This assemblage represents the first major otolith association described from the Bessarabian. It also represents a fish fauna from the last continuous restricted marine environment that evolved in the Eastern Paratethys, was recruited from the Badenian/Tarkhanian fauna, and was not affected by the subsequent Khersonian crisis. The association of otoliths is characterized by a high content of endemic fishes that derived from the relatively well-known early Sarmatian s.l. (Volhynian) fish fauna, and it contains certain faunal elements that were trapped in the then-secluded Eastern Paratethys and did not range into younger strata. This forced endemic evolution explains the unusually high percentage of new taxa. \n\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 The fish fauna is dominated by stenohaline marine shelf fishes apparently recruited from the Konkian and earlier Sarmatian s.l. (Volhynian) fauna after the Karaganian crisis. The families Gobiidae and Gadidae benefited most in this restricted marine environment, while deep-water fishes disappeared with the Karaganian crisis. In this study, we discuss the further evolution of Eastern Paratethyan fishes as far as can be reconstructed from the relatively limited data from post-Bessarabian strata, and we also outline targets for future research in the field. \nThe stratigraphic sequence of the Jurkine section is being revised based on a detailed suite of benthic foraminifera. Implications for the stratigraphy of the middle and upper Sarmatian s.l., their boundary, and the paleoenvironments of this part of the Kerch Peninsula are discussed.", "keyphrases": ["fish fauna", "otoliths", "kerch peninsula"]}
{"id": "10.1111/j.1502-3931.2007.00091.x", "title": "A biomechanical constraint on body mass in terrestrial mammalian predators", "abstract": ", Vol. 41, pp. 333\u2013347Observations on extant mammals suggest that large body mass is selectively advanta-geous for a terrestrial predator on large herbivores. Yet, throughout the Cenozoic, somelineages of terrestrial mammalian predators attained greater maximal body masses thanothers. In order to explain this evolutionary pattern, the following biomechanical con-straint on body mass is hypothesized. The stress, set up in the humerus by the bendingmoment of the peak ground reaction force at maximal running speed, increased withincreasing body mass within a given lineage of terrestrial mammalian predators, resultingin a decreasing safety factor for the bone, until a predator could no longer attain themaximal running speed of its smaller relatives. The selective disadvantage of reducedmaximal running speed prevented further increase of body mass within the lineage.This hypothesis is tested by examining the scaling of humeral dimensions andestimating maximal body masses in several lineages of terrestrial mammalian predators.Among lineages with otherwise similar postcranial skeletons, those with the more robusthumeri at a given body mass attained the greater maximal body masses. Lineages withthe longer deltoid ridges/deltopectoral crests of the humeri and/or the more distallylocated deltoid scars (suggesting the more distal insertions of the humeral flexors) at agiven body mass also attained the greater maximal body masses. These results supportthe existence of the proposed biomechanical constraint, although paleoecological datasuggest that some lineages of terrestrial mammalian predators failed to reach the limits,imposed by this constraint, because of the small size of available prey.", "keyphrases": ["biomechanical constraint", "body mass", "terrestrial mammalian predator"]}
{"id": "10.1126/science.1253293", "title": "An integrative approach to understanding bird origins", "abstract": "Background The origin of birds is one of the most enduring and dramatic evolutionary debates. The hypothesis that the primarily small-sized birds are nested within a theropod dinosaur group that includes the gigantic Tyrannosaurus rex has been supported by strong fossil evidence, but until recently, several important issues remained unresolved, including the origins of feathers and flight, the \u201ctemporal paradox\u201d (the coelurosaurian theropods occur too late in the fossil record to be ancestral to the Jurassic bird Archaeopteryx), and supposed homological incongruities (e.g., the suggested homologies of three fingers in tetanuran theropods are different from those of living birds). Recent discoveries of spectacular dinosaur fossils from China and elsewhere provide new information to address these issues, and also prompt numerous studies in disciplines other than paleontology that help explain how bird characteristics originated and evolved. Evolutionary history of selected bird features inferred from multidisciplinary data. Recent studies demonstrate that major bird characteristics have evolved in a sequential way, and many of them initiated transformation early in dinosaur evolution, with some approaching modern conditions well before the origin of birds, whereas others appear only near the origin of the crown group birds. Advances The discoveries of feathered dinosaur fossils from the Jurassic and Cretaceous sediments of China and elsewhere document a diverse range of feathers from monofilamentous feathers to highly complex flight feathers, which show a general evolutionary trend of increasing complexity leading to the cladogenesis of birds. The wide occurrence of foot feathers in Mesozoic theropods (i.e., short filamentous forms in relatively basal theropods and large vaned forms in derived theropods, including early birds) clarifies feather-scale relations and integumentary evolution pertinent to flight origins and also shows that bird flight likely had evolved through a four-winged stage. With numerous discoveries of well-preserved dinosaur fossils covering a wide range of geological periods, the morphological, functional, and temporal transition from ground-living to flight-capable theropod dinosaurs is now one of the best-documented major evolutionary transitions. Meanwhile, studies in disciplines other than paleontology provide new insights into how bird characteristics originated and evolved\u2014such as feathers, flight, endothermic physiology, unique strategies for reproduction and growth, and an unusual pulmonary system. The iconic features of extant birds, for the most part, evolved in a gradual and stepwise fashion throughout theropod evolution. However, new data also highlight occasional bursts of morphological novelty at certain stages particularly close to the origin of birds and an unavoidable complex, mosaic evolutionary distribution of major bird characteristics on the theropod tree. Research into bird origins provides a model example of how an integration of paleontological and neontological data can be used to gain a comprehensive understanding of the complexity surrounding major evolutionary transitions and to set new research directions. Outlook A refined, more robust phylogeny will be imperative to move our studies forward. A larger data set will help to increase the accuracy of phylogenetic reconstructions, but better character formulation and more accurate scorings are imperative at the current stage. In terms of character evolution, an integrative approach combining paleontological, neontological, developmental, temporal, and even paleoenvironmental data is particularly desirable. Greater examination of fossils pertaining to molecular information is also a potentially fruitful avenue for future investigation. Evolutionary scenarios for various aspects of the origin of birds have sometimes been constructed from neontological data, but any historical reconstruction must ultimately be tested using the fossil record. Consequently, dense fossil sampling along the line to modern birds and better understanding of transitional forms play key roles in such reconstructions. Recent discoveries of spectacular dinosaur fossils overwhelmingly support the hypothesis that birds are descended from maniraptoran theropod dinosaurs, and furthermore, demonstrate that distinctive bird characteristics such as feathers, flight, endothermic physiology, unique strategies for reproduction and growth, and a novel pulmonary system originated among Mesozoic terrestrial dinosaurs. The transition from ground-living to flight-capable theropod dinosaurs now probably represents one of the best-documented major evolutionary transitions in life history. Recent studies in developmental biology and other disciplines provide additional insights into how bird characteristics originated and evolved. The iconic features of extant birds for the most part evolved in a gradual and stepwise fashion throughout archosaur evolution. However, new data also highlight occasional bursts of morphological novelty at certain stages particularly close to the origin of birds and an unavoidable complex, mosaic evolutionary distribution of major bird characteristics on the theropod tree. Research into bird origins provides a premier example of how paleontological and neontological data can interact to reveal the complexity of major innovations, to answer key evolutionary questions, and to lead to new research directions. A better understanding of bird origins requires multifaceted and integrative approaches, yet fossils necessarily provide the final test of any evolutionary model. Bird evolution: How birds took to the air Research on the origin and evolution of birds has gathered pace in recent years, aided by a continuous stream of new fossil finds as well as molecular phylogenies. Bird origins, in particular, are now better understood than those of mammals, for which the early fossil record is relatively poor compared with that of birds. Xu et al. review progress in tracing the origins of birds from theropod dinosaurs, focusing especially on recent fossil finds of feathered dinosaurs of northeastern China. They integrate current research on developmental biology and functional anatomy with the paleontological record, to show how key features of birds\u2014feathers, wings, and flight\u2014originated and evolved, and radiated from their dinosaur forebears. Science, this issue 10.1126/science.1253293", "keyphrases": ["integrative approach", "bird origin", "feather", "flight"]}
{"id": "10.11646/zootaxa.3884.3.4", "title": "An advanced, new long-legged bird from the Early Cretaceous of the Jehol Group (northeastern China): insights into the temporal divergence of modern birds.", "abstract": "We describe a new ornithuromorph bird species, Gansus zheni from the Lower Cretaceous lacustrine deposits of the Jiufotang Formation (Jehol Group), Liaoning Province, China. A cladistic analysis resolves Gansus zheni as the sister taxon of the roughly contemporaneous Gansus yumenensis (Xiagou Formation, Gansu Province), and together as the most immediate outgroup to Ornithurae. Gansus zheni is the most advanced bird known today for the Jehol Biota. Its discovery provides the best-documented case of inter-basinal correlations (Jehol and Changma basins of Liaoning and Gansu provinces, respectively) using low-taxonomic clades of fossil birds. The existence of close relatives of Ornithurae in deposits formed at about 120 million years ago helps to mitigate the long-standing controversy between molecular and paleontological evidence for the temporal divergence of modern birds (Neornithes).", "keyphrases": ["china", "temporal divergence", "modern bird", "gansus zheni"]}
{"id": "paleo.010340", "title": "Unlocking the early fossil record of the arthropod central nervous system", "abstract": "Extant panarthropods (euarthropods, onychophorans and tardigrades) are hallmarked by stunning morphological and taxonomic diversity, but their central nervous systems (CNS) are relatively conserved. The timing of divergences of the ground pattern CNS organization of the major panarthropod clades has been poorly constrained because of a scarcity of data from their early fossil record. Although the CNS has been documented in three-dimensional detail in insects from Cenozoic ambers, it is widely assumed that these tissues are too prone to decay to withstand other styles of fossilization or geologically older preservation. However, Cambrian Burgess Shale-type compressions have emerged as sources of fossilized brains and nerve cords. CNS in these Cambrian fossils are preserved as carbon films or as iron oxides/hydroxides after pyrite in association with carbon. Experiments with carcasses compacted in fine-grained sediment depict preservation of neural tissue for a more prolonged temporal window than anticipated by decay experiments in other media. CNS and compound eye characters in exceptionally preserved Cambrian fossils predict divergences of the mandibulate and chelicerate ground patterns by Cambrian Stage 3 (ca 518 Ma), a dating that is compatible with molecular estimates for these splits.", "keyphrases": ["early fossil record", "nervous system", "tissue", "decay experiment"]}
{"id": "10.1111/nph.13024", "title": "First evidence of mutualism between ancient plant lineages (Haplomitriopsida liverworts) and Mucoromycotina fungi and its response to simulated Palaeozoic changes in atmospheric CO2", "abstract": "The discovery that Mucoromycotina, an ancient and partially saprotrophic fungal lineage, associates with the basal liverwort lineage Haplomitriopsida casts doubt on the widely held view that Glomeromycota formed the sole ancestral plant\u2013fungus symbiosis. Whether this association is mutualistic, and how its functioning was affected by the fall in atmospheric CO2 concentration that followed plant terrestrialization in the Palaeozoic, remains unknown. We measured carbon-for-nutrient exchanges between Haplomitriopsida liverworts and Mucoromycotina fungi under simulated mid-Palaeozoic (1500 ppm) and near-contemporary (440 ppm) CO2 concentrations using isotope tracers, and analysed cytological differences in plant\u2013fungal interactions. Concomitantly, we cultured both partners axenically, resynthesized the associations in vitro, and characterized their cytology. We demonstrate that liverwort\u2013Mucoromycotina symbiosis is mutualistic and mycorrhiza-like, but differs from liverwort\u2013Glomeromycota symbiosis in maintaining functional efficiency of carbon-for-nutrient exchange between partners across CO2 concentrations. Inoculation of axenic plants with Mucoromycotina caused major cytological changes affecting the anatomy of plant tissues, similar to that observed in wild-collected plants colonized by Mucoromycotina fungi. By demonstrating reciprocal exchange of carbon for nutrients between partners, our results provide support for Mucoromycotina establishing the earliest mutualistic symbiosis with land plants. As symbiotic functional efficiency was not compromised by reduced CO2, we suggest that other factors led to the modern predominance of the Glomeromycota symbiosis.", "keyphrases": ["haplomitriopsida liverwort", "mucoromycotina", "atmospheric co2 concentration"]}
{"id": "paleo.010728", "title": "Proboscidean Mitogenomics: Chronology and Mode of Elephant Evolution Using Mastodon as Outgroup", "abstract": "We have sequenced the complete mitochondrial genome of the extinct American mastodon (Mammut americanum) from an Alaskan fossil that is between 50,000 and 130,000 y old, extending the age range of genomic analyses by almost a complete glacial cycle. The sequence we obtained is substantially different from previously reported partial mastodon mitochondrial DNA sequences. By comparing those partial sequences to other proboscidean sequences, we conclude that we have obtained the first sequence of mastodon DNA ever reported. Using the sequence of the mastodon, which diverged 24\u201328 million years ago (mya) from the Elephantidae lineage, as an outgroup, we infer that the ancestors of African elephants diverged from the lineage leading to mammoths and Asian elephants approximately 7.6 mya and that mammoths and Asian elephants diverged approximately 6.7 mya. We also conclude that the nuclear genomes of the African savannah and forest elephants diverged approximately 4.0 mya, supporting the view that these two groups represent different species. Finally, we found the mitochondrial mutation rate of proboscideans to be roughly half of the rate in primates during at least the last 24 million years.", "keyphrases": ["elephant", "mastodon", "outgroup", "elephantidae lineage", "mammoth"]}
{"id": "paleo.009143", "title": "Dental Microwear and Diet of the Plio-Pleistocene Hominin Paranthropus boisei", "abstract": "The Plio-Pleistocene hominin Paranthropus boisei had enormous, flat, thickly enameled cheek teeth, a robust cranium and mandible, and inferred massive, powerful chewing muscles. This specialized morphology, which earned P. boisei the nickname \u201cNutcracker Man\u201d, suggests that this hominin could have consumed very mechanically challenging foods. It has been recently argued, however, that specialized hominin morphology may indicate adaptations for the consumption of occasional fallback foods rather than preferred resources. Dental microwear offers a potential means by which to test this hypothesis in that it reflects actual use rather than genetic adaptation. High microwear surface texture complexity and anisotropy in extant primates can be associated with the consumption of exceptionally hard and tough foods respectively. Here we present the first quantitative analysis of dental microwear for P. boisei. Seven specimens examined preserved unobscured antemortem molar microwear. These all show relatively low complexity and anisotropy values. This suggests that none of the individuals consumed especially hard or tough foods in the days before they died. The apparent discrepancy between microwear and functional anatomy is consistent with the idea that P. boisei presents a hominin example of Liem's Paradox, wherein a highly derived morphology need not reflect a specialized diet.", "keyphrases": ["morphology", "food", "dental microwear", "microwear feature"]}
{"id": "paleo.001040", "title": "Neoichnology of the desert scorpion Hadrurus arizonensis: burrows to biogenic cross lamination", "abstract": "Bioturbation by terrestrial animals is common in arid and semi-arid continental environments. Scorpions have comprised a significant portion of the diversity of predatory arthropods in these environments from the Late Paleozoic to the Recent. Many scorpions are active burrowers and likely have a substantial, if rarely recognized, ichnofossil record. This project involved the study of the burrowing behaviors and trace morphologies of the scorpion Hadrurus arizonensis (Scorpiones: Caraboctonidae). Individual animals were placed into sediment-filled terrariums for two-to three-week periods after which burrows were cast, excavated, and described. Descriptions of the subsurface structures included architecture, dimensions, bioglyphs, complexity, and tortuosity. Additional experiments were run with differing sediment composition, density, and moisture to evaluate the animal's behavioral response to altering environmental conditions. Specimens of H. arizonensis burrowed by scratching and kicking loose sediment from the subsurface with the first two to three pairs of walking legs. The subsurface biogenic structures produced consisted of subvertical ramps, U-shaped burrows, helical burrows, and mazeworks. In the process of excavating the burrows, the desert scorpions also produced a hummocky surface topography as well as structures in dry, sandy sediment that resembled lamination and ripple cross-lamination. Increasing clay content and sediment density increased the complexity of burrow architectures produced. Reducing these variables limited the complexity of the burrows, reduced their likelihood of preservation, and increased the abundance of biogenic cross-lamination. Data collected from these and similar experimental studies can be applied to terrestrial ichnofossil assemblages in order to better interpret the paleoecology of ancient soil ecosystems.", "keyphrases": ["scorpion", "burrow", "biogenic structure", "variable"]}
{"id": "10.4072/rbp.2015.3.14", "title": "Actualizaci\u00f3n sistem\u00e1tica y filogenia de los proterotheriidae (Mammalia, litopterna) del \u201cMesopotamiense\u201d (mioceno tard\u00edo) de Entre R\u00edos, Argentina", "abstract": "A systematic update of the species of Proterotheriidae (Litopterna) from the \u201cMesopotamiense\u201d of Entre Rios Province (Argentina) is performed, and their phylogenetic relationships with other members of the family are tested. Brachytherium cuspidatum Ameghino is validated (considered nomen dubium hitherto) and a sexual dimorphism is proposed for this species. This idea is based on metric, but not morphological, differences among the specimens included in it, which is supported by a discriminant analysis. Neobrachytherium ameghinoi Soria and Proterotherium cervioides Ameghino are also valid, and Epitherium? eversus (Ameghino) is assigned to the genus Diadiaphorus. Detailed descriptions of the specimens are presented for each taxon, and their diagnosis are revised.", "keyphrases": ["proterotheriidae", "litopterna", "mesopotamiense", "argentina"]}
{"id": "10.1002/jqs.1285", "title": "Gigantism of the Australian Diprotodon Owen 1838 (Marsupialia, Diprotodontoidea) through the Pleistocene", "abstract": "Diprotodon Owen, 1838 was one of the first fossil mammals described from Australia and has the distinction of being the largest ever marsupial. However, until recently its taxonomy was unclear and knowledge of its continental distribution, palaeoecology and evolution was poorly known. This paper describes cranial elements from an unusually small\u2010bodied Diprotodon from the Early Pleistocene Nelson Bay Formation, Portland, Australia. It is intermediate in size between the smaller\u2010bodied Pliocene ancestor, Euryzygoma dunense de Vis 1895 and the larger\u2010bodied Late Pleistocene D. optatum Owen, 1838 . However, it is morphologically inseparable from Late Pleistocene Diprotodon and is here referred to as D. ?optatum. A temporal morphocline most parsimoniously explains the medium body size of the Nelson Bay taxon; thus we provide the first evidence of a transitional form within Diprotodon. The cause(s) of gigantism of the E. dunense\u2013D. ?optatum\u2013D. optatum lineage through the late Cainozoic is unclear but most likely involved the physiological response to changes in the physical and/or biotic environment. Although the size changes within the lineage may have been initially advantageous, they were most likely disadvantageous when the optimum body size was obtained. Our results suggest that Diprotodon was at its largest ever body size during the Late Pleistocene \u2013 the time period that coincided with its extinction. Copyright \u00a9 2009 John Wiley & Sons, Ltd.", "keyphrases": ["late pleistocene", "body size", "gigantism"]}
{"id": "10.1080/02724634.2011.618155", "title": "The First Known Asian Hispanomeryx (Mammalia, Ruminantia, Moschidae)", "abstract": "The first known Asian Hispanomeryx (Mammalia, Ruminantia, Moschidae) Israel M. Sanchez a , Daniel Demiguel b , Victoria Quiralte a & Jorge Morales a a Departamento de Paleobiologia, Museo Nacional de Ciencias Naturales-CSIC, C/ Jose Gutierrez Abascal 2, 28006, Madrid, Spain b Institut Catala de Paleontologia, Universitat Autonoma de Barcelona, Edifici ICP, Campus de la UAB s/n, 08193, Cerdanyola del Valles, Barcelona, Spain", "keyphrases": ["asian hispanomeryx", "mammalia", "moschidae"]}
{"id": "10.1111/j.1472-4669.2011.00305.x", "title": "Microbes and mass extinctions: paleoenvironmental distribution of microbialites during times of biotic crisis", "abstract": "Widespread development of microbialites characterizes the substrate and ecological response during the aftermath of two of the \u2018big five\u2019 mass extinctions of the Phanerozoic. This study reviews the microbial response recorded by macroscopic microbial structures to these events to examine how extinction mechanism may be linked to the style of microbialite development. Two main styles of response are recognized: (i) the expansion of microbialites into environments not previously occupied during the pre\u2010extinction interval and (ii) increases in microbialite abundance and attainment of ecological dominance within environments occupied prior to the extinction. The Late Devonian biotic crisis contributed toward the decimation of platform margin reef taxa and was followed by increases in microbialite abundance in Famennian and earliest Carboniferous platform interior, margin, and slope settings. The end\u2010Permian event records the suppression of infaunal activity and an elimination of metazoan\u2010dominated reefs. The aftermath of this mass extinction is characterized by the expansion of microbialites into new environments including offshore and nearshore ramp, platform interior, and slope settings. The mass extinctions at the end of the Triassic and Cretaceous have not yet been associated with a macroscopic microbial response, although one has been suggested for the end\u2010Ordovician event. The case for microbialites behaving as \u2018disaster forms\u2019 in the aftermath of mass extinctions accurately describes the response following the Late Devonian and end\u2010Permian events, and this may be because each is marked by the reduction of reef communities in addition to a suppression of bioturbation related to the development of shallow\u2010water anoxia.", "keyphrases": ["mass extinction", "microbialite", "biotic crisis", "slope setting", "nearshore ramp"]}
{"id": "paleo.009100", "title": "Fossil and Genetic Evidence for the Polyphyletic Nature of the Planktonic Foraminifera \"Globigerinoides\", and Description of the New Genus Trilobatus", "abstract": "Planktonic foraminifera are one of the most abundant and diverse protists in the oceans. Their utility as paleo proxies requires rigorous taxonomy and comparison with living and genetically related counterparts. We merge genetic and fossil evidence of \u201cGlobigerinoides\u201d, characterized by supplementary apertures on spiral side, in a new approach to trace their \u201ctotal evidence phylogeny\u201d since their first appearance in the latest Paleogene. Combined fossil and molecular genetic data indicate that this genus, as traditionally understood, is polyphyletic. Both datasets indicate the existence of two distinct lineages that evolved independently. One group includes \u201cGlobigerinoides\u201d trilobus and its descendants, the extant \u201cGlobigerinoides\u201d sacculifer, Orbulina universa and Sphaeroidinella dehiscens. The second group includes the Globigerinoides ruber clade with the extant G. conglobatus and G. elongatus and ancestors. In molecular phylogenies, the trilobus group is not the sister taxon of the ruber group. The ruber group clusters consistently together with the modern Globoturborotalita rubescens as a sister taxon. The re-analysis of the fossil record indicates that the first \u201cGlobigerinoides\u201d in the late Oligocene are ancestral to the trilobus group, whereas the ruber group first appeared at the base of the Miocene with representatives distinct from the trilobus group. Therefore, polyphyly of the genus \"Globigerinoides\" as currently defined can only be avoided either by broadening the genus concept to include G. rubescens and a large number of fossil species without supplementary apertures, or if the trilobus group is assigned to a separate genus. Since the former is not feasible due to the lack of a clear diagnosis for such a broad genus, we erect a new genus Trilobatus for the trilobus group (type species Globigerina triloba Reuss) and amend Globoturborotalita and Globigerinoides to clarify morphology and wall textures of these genera. In the new concept, Trilobatus n. gen. is paraphyletic and gave rise to the Praeorbulina / Orbulina and Sphaeroidinellopsis / Sphaeroidinella lineages.", "keyphrases": ["planktonic foraminifera", "globigerinoides", "new genus trilobatus", "descendant", "sphaeroidinella"]}
{"id": "10.1111/j.1095-8312.2001.tb01368.x", "title": "Patterns of animal dispersal, vicariance and diversification in the Holarctic", "abstract": "We analysed patterns of animal dispersal, vicariance and diversification in the Holarctic based on complete phylogenies of 57 extant non-marine taxa, together comprising 770 species, documenting biogeographic events from the Late Mesozoic to the present. Four major areas, each corresponding to a historically persistent landmass, were used in the analyses: eastern Nearctic (EN), western Nearctic (WN), eastern Palaeoarctic (EP) and western Palaeoarctic (WP). Parsimony-based tree fitting showed that there is no significantly supported general area cladogram for the dataset. Yet, distributions are strongly phylogenetically conserved, as revealed by dispersalvicariance analysis (DIVA). DIVA-based permutation tests were used to pinpoint phylogenetically determined biogeographic patterns. Consistent with expectations, continental dispersals (WP\u2194EP and WN\u2194EN) are significantly more common than palaeocontinental dispersals (WN\u2194EP and EN\u2194WP), which in turn are more common than disjunct dispersals (EN\u2194EP and WN\u2194WP). There is significant dispersal asymmetry both within the Nearctic (WN\u2192EN more common than EN\u2192WN) and the Palaeoarctic (EP\u2192WP more common than WP\u2192EP). CrossBeringian faunal connections have traditionally been emphasized but are not more important than cross-Atlantic connections in our data set. To analyse changes over time, we sorted biogeographic events into four major time periods using fossil, biogeographic and molecular evidence combined with a \u2018branching clock\u2019. These analyses show that trans-Atlantic distributions (EN\u2013WP) were common in the Early\u2013Mid Tertiary (70\u201320 Myr), whereas transBeringian distributions (WN\u2013EP) were rare in that period. Most EN\u2013EP disjunctions date back to the Early Tertiary (70\u201345 Myr), suggesting that they resulted from division of cross-Atlantic rather than cross-Beringian distributions. Diversification in WN and WP increased in the Quaternary (< 3 Myr), whereas in EP and EN it decreased from a maximum in the Early\u2013Mid Tertiary. \uf6d9 2001 The Linnean Society of London", "keyphrases": ["animal dispersal", "vicariance", "holarctic"]}
{"id": "10.1017/pab.2016.38", "title": "Asymmetric geographic range expansion explains the latitudinal diversity gradients of four major taxa of marine plankton", "abstract": "Abstract. \n Extensive investigation of the close association between biological diversity and environmental temperature has not yet yielded a generally accepted, empirically validated mechanism to explain latitudinal gradients of species diversity, which occur in most taxa. Using the highly resolved late Cenozoic fossil records of four major taxa of marine plankton, we show that their gradients arise as a consequence of asymmetric geographic range expansion rather than latitudinal variation in diversification rate, as commonly believed. Neither per capita speciation nor extinction rates trend significantly with temperature or latitude for these marine plankton. Species of planktonic foraminifera and calcareous nannoplankton that originate in the temperate zone preferentially spread toward and arrive earlier in the tropics to produce a normal gradient with tropical diversity peaks; by contrast, temperate-zone originating species of diatoms and radiolarians preferentially spread toward and arrive earlier in polar regions to produce reversed gradients with high-latitude diversity peaks. Our results suggest that temperature affects latitudinal diversity gradients chiefly by its effect on species' range limits rather than on probabilities of speciation and extinction. We show that this mechanism also appears to operate in various multicellular taxa, thus providing a widely applicable explanation for the origin of latitudinal diversity gradients.", "keyphrases": ["geographic range expansion", "latitudinal diversity gradient", "marine plankton"]}
{"id": "paleo.007869", "title": "A gigantic nothosaur (Reptilia: Sauropterygia) from the Middle Triassic of SW China and its implication for the Triassic biotic recovery", "abstract": "The presence of gigantic apex predators in the eastern Panthalassic and western Tethyan oceans suggests that complex ecosystems in the sea had become re-established in these regions at least by the early Middle Triassic, after the Permian-Triassic mass extinction (PTME). However, it is not clear whether oceanic ecosystem recovery from the PTME was globally synchronous because of the apparent lack of such predators in the eastern Tethyan/western Panthalassic region prior to the Late Triassic. Here we report a gigantic nothosaur from the lower Middle Triassic of Luoping in southwest China (eastern Tethyan ocean), which possesses the largest known lower jaw among Triassic sauropterygians. Phylogenetic analysis suggests parallel evolution of gigantism in Triassic sauropterygians. Discovery of this gigantic apex predator, together with associated diverse marine reptiles and the complex food web, indicates global recovery of shallow marine ecosystems from PTME by the early Middle Triassic.", "keyphrases": ["gigantic nothosaur", "middle triassic", "biotic recovery", "mass extinction", "marine reptile"]}
{"id": "10.1073/pnas.0409518102", "title": "The position of Hippopotamidae within Cetartiodactyla.", "abstract": "The origin of late Neogene Hippopotamidae (Artiodactyla) involves one of the most serious conflicts between comparative anatomy and molecular biology: is Artiodactyla paraphyletic? Molecular comparisons indicate that Cetacea should be the modern sister group of hippos. This finding implies the existence of a fossil lineage linking cetaceans (first known in the early Eocene) to hippos (first known in the middle Miocene). The relationships of hippos within Artiodactyla are challenging, and the immediate affinities of Hippopotamidae have been studied by biologists for almost two centuries without resolution. Here, we compare opposing hypotheses implicating several \"suiform\" families. This morphological analysis of a comprehensive set of taxa and characters offers a robust solution to the origins of Hippopotamidae. This family appears to be deeply nested within the otherwise extinct artiodactyl family Anthracotheriidae, most precisely within the most advanced selenodont forms. The proposed sister group of hippos is the middle to late Miocene African semiaquatic Libycosaurus. Any close relationships of hippos with suoids, particularly with Tayassuidae, are rejected. Furthermore, the clade (Hippopotamidae, Anthracotheriidae) is proposed as the sister group of the Cetacea, offering broad morphological support for a molecular phylogeny, such support being also consistent with the fossil record. Corroboration of this relationship requires an exploration of anthracothere affinities with other Paleogene artiodactyls. Among those, the position of Ruminantia is a central question, still to be solved. Further progress in this debate is likely to come from morphological studies of paleontological data, whether known or still to be discovered.", "keyphrases": ["hippopotamidae", "cetacea", "anthracotheriidae"]}
{"id": "10.1002/spp2.1345", "title": "A Hirnantian holdover from the Late Ordovician mass extinction: phylogeny and biogeography of a new anthracocrinid crinoid from Estonia", "abstract": "Relatively few Hirnantian (Late Ordovician) crinoids are known, and none has been previously described from the palaeocontinent of Baltica. This has impaired our ability to understand the patterns of extinction and biogeographic dispersal surrounding the Late Ordovician mass extinction, which triggered a major turnover in crinoid faunas. Here, we describe Tallinnicrinus toomae gen. et sp. nov., an anthracocrinid diplobathrid from the Hirnantian of northern Estonia. Tallinnicrinus is the youngest member of the Anthracocrinidae and the first representative of the family to occur in Baltica. Morphologically, Tallinnicrinus is unusual in that the radial and basal plates are in a single circlet of 10 plates, similar to the anthracocrinid Rheocrinus Haugh, 1979 from the Katian of Laurentia. Phylogenetic analysis further confirms a close relationship between Tallinnicrinus and Laurentian anthracocrinids, suggesting biogeographic dispersal of the lineage from Laurentia to Baltica during the late Katian or early Hirnantian. The occurrence of this new taxon establishes that the family Anthracocrinidae survived the first pulse of the Late Ordovician mass extinction. However, the lineage remained a \u2018dead clade walking\u2019 because it failed to diversify in the wake of the end\u2010Katian extinction and ultimately went extinct itself by the end of the Ordovician.", "keyphrases": ["ordovician mass extinction", "crinoid", "estonia", "crinoid faunas"]}
{"id": "paleo.006045", "title": "Alleged Cnidarian Sphenothallus in the Late Ordovician of Baltica, Its Mineral Composition and Microstructure", "abstract": "Sphenothallus is a problematic fossil with possible cnidarian affinities. Two species of Sphenothallus, S. aff. longissimus and S. kukersianus, occur in the normal marine sediments of the Late Ordovician of Estonia. S. longissimus is more common than S. kukersianus and has a range from early Sandbian to middle Katian. Sphenothallus had a wide paleobiogeographic distribution in the Late Ordovician. The tubes of Sphenothallus are composed of lamellae with a homogeneous microstructure. The homogeneous microstructure could represent a diagenetic fabric, based on the similarity to diagenetic structures in Torellella (Cnidaria?, Hyolithelminthes). Tubes of Sphenothallus have an apatitic composition, but one tube contains lamellae of diagenetic calcite within the apatitic structure. Sphenothallus presumably had originally biomineralized apatitic tubes. Different lattice parameters of the apatite indicate that biomineralization systems of phosphatic cnidarians Sphenothallus and Conularia sp. may have been different.", "keyphrases": ["sphenothallus", "late ordovician", "microstructure", "apatite"]}
{"id": "10.1080/03122417.2012.11681932", "title": "Forum The Restaurant At The End Of The Universe: Modelling the colonisation of Sahul", "abstract": "Abstract Elsewhere we have developed a speculative model of the early human colonisation of Sahul (Pleistocene Australia-New Guinea). Here we elaborate it, using theory from behavioural ecology, and data from palaeoclimatology and modern hunter-gatherer ethnography. We argue that colonisers focused mainly on coastal ecotones while crossing Wallacea, but spread more widely across favourable habitats after landing on Sahul. Movement was archaeologically instantaneous, driven primarily by serial depletion of high-ranked prey. Human populations subsequently remained far smaller than sometimes imagined, probably because of difficult climatic and environmental conditions. Archaeological data are generally consistent with these expectations. These findings challenge the frequent assertion that human colonisation alone led to significant changes in Sahul ecology, and may help explain the simplicity of its Pleistocene lithic technology.", "keyphrases": ["colonisation", "sahul", "wallacea", "human population"]}
{"id": "10.1080/02724634.2017.1269116", "title": "Structure of the Nasal Region of Non-Mammalian Cynodonts and Mammaliaforms: Speculations on the Evolution of Mammalian Endothermy", "abstract": "ABSTRACT Nasal regions of the non-mammalian cynodonts Massetognathus, Probainognathus, and Elliotherium were reconstructed from micro-computed tomography scans and compared with scans and published accounts of more derived forms, including Brasilitherium, Morganucodon, Haldanodon, and extant mammals. The basic structure of the modern mammalian nose, already present in non-mammalian cynodonts of the Early Triassic, underwent little modification during the Triassic. A respiratory chamber opened into a nasopharyngeal passage through an enlarged primary choana bordered posteriorly by a transverse lamina that formed the floor to a more posterior olfactory chamber. Cartilaginous respiratory turbinals initially provided a surface for evaporative cooling during periods of increased activity in the exceptionally high ambient temperatures of the Triassic. A similar mechanism for heat loss is present in extant crocodilians, squamates, and mammals. In the Late Triassic and Early Jurassic non-mammaliaform cynodonts (Elliotherium) and mammaliaforms (Morganucodon), the pterygopalatine ridges behind the hard secondary palate extended ventrally and formed the lateral walls to a narrow nasopharynx, as pterygoid hamuli do in extant mammals. Ridges in this position suggest the presence of a palatopharyngeus muscle in late non-mammaliaform cynodonts that could hold the larynx in an intranarial position during rest or low activity levels to prevent inhaled air from entering the oral cavity, thus allowing cartilaginous respiratory turbinals to assume an additional role as temporal countercurrent exchange sites for heat and water conservation. Ossification of respiratory turbinals in mammals enhanced their efficiency for conserving heat and water at rest, as well as their ability to dissipate heat during thermal stress.", "keyphrases": ["nasal region", "mammaliaform", "mammalian endothermy", "morganucodon", "respiratory turbinal"]}
{"id": "paleo.001192", "title": "Non-linear ontogenetic shape change in Cryptolithus tesselatus (Trilobita) using three-dimensional geometric morphometrics", "abstract": "A decrease in the rate of cephalic shape change late in ontogeny has been documented for several species of trilobites, possibly associated with the cessation of segment release into the thorax. Qualitative descriptions of the ontogeny of Cryptolithus tesselatus Green, 1832, suggest that shape change in the cephalon was strongly influenced by the progressive accommodation of large funnel-shaped perforations (\u201cfringepits\u201d) over several molts. The number and arrangement of fringe-pits was established early in ontogeny, however, before thoracic segment release was completed. Due to the unusual and highly convex shape of the cephalon, we use three-dimensional (3D) geometric morphometrics to quantify shape change in this species and determine if there is a rate shift, and at what point in development this shift occurred. Three-dimensional morphometrics was made possible by extracting fixed and semi-landmarks from surface reconstructions of C. tesselatus rendered from CT scans of silicified specimens. Results show that the cephalon continued to change shape into adulthood, but that a threshold model with a rate shift associated with the cessation of new fringe-pits is best supported. 2D landmarks taken from the dorsal view fail to capture the dramatic change in convexity of the cephalon during development, but model comparison results are consistent with those based on the 3D landmark dataset, allowing comparison of this aspect of ontogenetic change with other species. Based on these comparisons, it appears that 1) trajectories are often better characterized by threshold models than simple linear regression models; 2) the timing of shifts may not be phylogeneti-", "keyphrases": ["shape change", "trilobite", "convexity"]}
{"id": "paleo.011796", "title": "Neandertal cannibalism and Neandertal bones used as tools in Northern Europe", "abstract": "Almost 150 years after the first identification of Neandertal skeletal material, the cognitive and symbolic abilities of these populations remain a subject of intense debate. We present 99 new Neandertal remains from the Troisi\u00e8me caverne of Goyet (Belgium) dated to 40,500\u201345,500 calBP. The remains were identified through a multidisciplinary study that combines morphometrics, taphonomy, stable isotopes, radiocarbon dating and genetic analyses. The Goyet Neandertal bones show distinctive anthropogenic modifications, which provides clear evidence for butchery activities as well as four bones having been used for retouching stone tools. In addition to being the first site to have yielded multiple Neandertal bones used as retouchers, Goyet not only provides the first unambiguous evidence of Neandertal cannibalism in Northern Europe, but also highlights considerable diversity in mortuary behaviour among the region\u2019s late Neandertal population in the period immediately preceding their disappearance.", "keyphrases": ["cannibalism", "neandertal bone", "northern europe", "belgium", "stable isotope"]}
{"id": "10.1002/ajmg.a.30539", "title": "Scott Rogers on dinosaur behavior, in: The Annals of Morphology", "abstract": "It is sad but true that you cannot have everything in life, a yardwithoutweeds,Utah summerswithout paperwasps, dogs without accidents, or dinosaur boneswith fossilized soft tissue. But, for just a brief moment though I thought I had one of the latter. This is a beautifully polished section of vertebral body from a dinosaur, most likely Allosaurus, from the Grand Junction, Colorado Morrison formation of the upper Jurassic, some 150million years old. To judge by its size, it was one of the last of the over 40 postsacral vertebrae of the animal lacking the dorsal portion of the medullary canal and the transverse and spinous processes. What appears at first glance to be fossilized spinal cord (some 31 mm in length are present) is nothing more than an endocast of a very fine-grained gray silt filling the medullary cavity. A 2 mm (on the average) darkercolored cortex of the endocastmayhave been themeninges, but then, wishful thinking can afflict even the toughest of old medical school professors. In any event, the minute space between the ventral surface of the endocast and dorsal rim of themedullary cavity is linedwith beautifulmicroscopic quartz crystals which also fill the cracks in the vertebral body. So, what is an endocast? For that the gracious reader is referred to the wonderful essay by Scott Rogers in this issue of the Journal. He is a fellow faculty member\u2014Professor of Neurobiology and Anatomy at this University, birth citizen of Utah (a state with a superabundance of well-preserved fossils) whose first words could not possibly have been mamma or dadda but Campsognathus and Heterodontosaurus (with a somewhat toothless lisp).Which is to say that Dr. Rogers is not only a distinguished anatomist and neurobiologist with particular expertise in the molecular biology of addictions and the auto-immune disorders of the brain but also a phenomenal paleontologist whose reconstruction of brain endocasts of Allosaurus have indeed made it possible to infer (some of) their behaviors. It is a never-forgotten experience to be privileged to accompany Scott and his equally accomplished neurobiologist wife Lorise Gahring and their dog \u2018\u2018Buck Rogers\u2019\u2019 (also a neuroscientist) on a fossil-digging field trip, for example, to the Cambrian trilobite beds of Delta, Utah. Initial attempts to relate form and function in fossils goes back to the very beginning of 19th century comparative anatomy and the pioneer paleontologists of that era [q.v. Russell, 1916]. Like them, Scott does so on the basis of two lines of evidence, namely, the structure of the part under consideration in relationship to the structure of the rest of the beast (or whatever is preserved of it), and, most importantly, and with greatest sophistication, an analysis of phylogenetic homology. In this particular case, the comparison between theAllosaurus andAlligator vestibular systems is compelling and beautifully illustrated. Thus, to some extent Scott Rogers follows in the footsteps of Cuvier [1769\u20131832], born a German Protestant working all of his life in Catholic France, the founder of paleozoology, most outstanding comparative anatomist ofhis day (until theadvent of theYoungerMeckel), and founder of the \u2018\u2018law of correlation,\u2019\u2019 formulated as follows [Outram, 1984]. \u2018\u2018Every living being constitutes a whole, a closed unit, in which all parts correspond to each other and contribute reciprocally to the same function. None of these parts can be changed without change in all the others; consequently, each part, taken as its own, designates and identifies all the others [Cuvier, 1812].\u2019\u2019 He went so far as to say, \u2018\u2018. . .the smallest bone, plane or apophysis, relates in a definite way to the class order, species, and genus towhich it belongs, and this goes so far, that with appropriate skill, clever application of the methods of analogy [nowadays homology], and actual comparison, each well-preserved piece of a bone is capable of determining all the other parts, as if the animal were before one [Cuvier, 1842].\u2019\u2019 At this endeavor Cuvier was spectacularly successful, but he failed in recognizing analogy as evidence for descent, and constrained all life forms into only four embranchements immutably created by God; and he represented the present diversity of organisms as remnants of catastrophic prior extinctions reducing the full palette of life intended by God. Thus, Cuvier not only, categorically, rejected the (somewhat inchoate) ideas on descent by his in-house colleague Lamarck but, far more aggressively, those of his other, in-house coworker (and previous co-author) Etienne Geoffroy StHilaire, whose notions on homologizing the dorso-ventral axis of vertebrates and invertebrates seemed to him the apotheosis of stultitude [Appel, 1987]. No such difficulties have beset Dr. Rogers. At a time when evolutionism is not only the normal mode of western biological thinking, but the dominant mode of framing testable hypotheses about homology and development, Scott has taken advantage of the extraordinary treasure of dinosaur fossils available in this state to use the venerable methods of morphology (aided by extremely sophisticated imaging techniques) to think about dinosaur behavior. Those clinician colleagues of mine who sneer \u2018\u2018who cares\u2019\u2019 about this kind of work have not learned the elementary lesson that everything that develops, whether normal or abnormal, has evolved, and that nothing can occur in development that evolution has not made possible. A lesson to be learned daily in clinic and at bedside when dealing with, for example, cleft palate, agenesis of corpus callosum, penoscrotal inversion, etc. Dinosaurs [Gr. deinos: terrible, sauros: lizard. R. Owen, 1841] evidently are members of the vertebrate class reptilia, specifically the subclass diapsida (characterized by two temporal fenestra); thus, they had a scaly skin and laid eggs with shells. This subclass is made up of two infraclasses: the archosauria (dinosaurs, sphenodontid reptiles, and crocodiles) and the lepidosauria (snakes and lizards). The two orders of *Correspondence to: John M. Opitz, 2C412 SOM, University of Utah, 50 N. Medical Drive, SLC, UT 84132. E-mail: john.opitz@hsc.utah.edu", "keyphrases": ["dinosaur behavior", "morphology", "scott rogers"]}
{"id": "10.1098/rspb.2007.0499", "title": "Shell bone histology indicates terrestrial palaeoecology of basal turtles", "abstract": "The palaeoecology of basal turtles from the Late Triassic was classically viewed as being semi-aquatic, similar to the lifestyle of modern snapping turtles. Lately, this view was questioned based on limb bone proportions, and a terrestrial palaeoecology was suggested for the turtle stem. Here, we present independent shell bone microstructural evidence for a terrestrial habitat of the oldest and basal most well-known turtles, i.e. the Upper Triassic Proterochersis robusta and Proganochelys quenstedti. Comparison of their shell bone histology with that of extant turtles preferring either aquatic habitats or terrestrial habitats clearly reveals congruence with terrestrial turtle taxa. Similarities in the shell bones of these turtles are a diploe structure with well-developed external and internal cortices, weak vascularization of the compact bone layers and a dense nature of the interior cancellous bone with overall short trabeculae. On the other hand, \u2018aquatic\u2019 turtles tend to reduce cortical bone layers, while increasing overall vascularization of the bone tissue. In contrast to the study of limb bone proportions, the present study is independent from the uncommon preservation of appendicular skeletal elements in fossil turtles, enabling the palaeoecological study of a much broader range of incompletely known turtle taxa in the fossil record.", "keyphrases": ["terrestrial palaeoecology", "basal turtle", "shell bone histology"]}
{"id": "paleo.000622", "title": "Early Cretaceous \"symmetrodont\" mammal Gobiotheriodon from Mongolia and the classification of \"Symmetrodonta\"", "abstract": "The \"symmetrodont\" mammal, Gobiotheriodon infinitus (Trofimov, 1980), from the Early Cretaceous (Aptian-Albian) of Mongolia, is redescribed. The species is restricted to the holotype only (dentary with three last molars), the referred maxillary fragment with M3? is considered here as cf. Gobiconodon sp. The dental formula of G. infinitus is reinterpreted as i1-3 c1 p1-3 m1-4. G. infinitus is characterized by a short dentary symphysis; long, well-developed Meckel's groove; small, triangular-shaped pterygoid fossa; weakly developed pterygoid crest; i3 enlarged; p1-3 two-rooted; lower molars acute-to obtuse-angled, labial cingulids lacking, lingual cingulids very short, well developed mesial and distal cingulid cuspules (\"e\" and \"d\") and prominent wear surface on the paracristid. Gobiotheriodon is similar to Tinodon (Late Jurassic, USA; Early Cretaceous, Great Britain and Portugal) in postcanine dental formula and structure of the pterygoid fossa; it is provisionally assigned to Tinodontidae Marsh, 1887. Some taxa previously assigned to (or suggested as possible relatives of) \"Symmetrodonta\" are reviewed. Amphidontidae Simpson, 1925 is considered as nomen dubium. A new classification for \"Symmetrodonta\" is proposed.", "keyphrases": ["symmetrodont", "gobiotheriodon", "mongolia", "spalacotheriid"]}
{"id": "10.1080/14772019.2010.528456", "title": "Phylogeny of the Notoungulata (Mammalia) based on cranial and dental characters", "abstract": "The Notoungulata is the richest order of South American endemic placentals, but phylogenetic relationships within this order are unclear. This work provides short descriptions of new cranial characters useful for phylogenetic research on notoungulates, argues for a redefinition of some characters on the dental cristae, and provides a long overdue treatment of notoungulate relationships \u2013 the most complete thus far \u2013 via a cladistic phylogenetic analysis comprising 50 notoungulate genera and 133 morphological characters of the skull and teeth. The monophyly of the Notoungulata (including Pyrotherium) is well supported by numerous cranial and dental apomorphies. The validity of most traditional notoungulates suprageneric taxa is tested, and the monophyly of the two traditional notoungulate suborders Toxodontia and Typotheria is supported. These two taxa are united in a clade supported by an original character on the morphology of the ectopterygoid crests. The Henricosborniidae, Isotemnidae and Oldfieldthomasiidae are paraphyletic, reflecting the fact that these families are mostly defined by plesiomorphic characters. The monophyly of Notohippidae is questioned, as well as the possibility of a close relationship between leontiniids and toxodontids on the basis of cranial arguments. It is observed that two major subclades diverge early within the Typotheria: the Interatheriidae and the clade Archaeohyracidae + Mesotheriidae + Hegetotheriidae. This new phylogeny of the notoungulates from cranial and dental anatomy is an essential step towards reconstructing the ancestral morphotype of the Notoungulata, and is crucial for research on the origin and phylogenetic affinities of these South American ungulates within the Placentalia.", "keyphrases": ["notoungulata", "typotheria", "interatheriidae", "phylogeny"]}
{"id": "10.1666/07062.1", "title": "Unveiling rare diversity by integrating museum, literature, and field data", "abstract": "Abstract Estimates of taxonomic richness and abundance are complicated by sampling biases. The failure to sample rare taxa is most often attributed to inadequate sampling and to removal during the process of sample-size standardization. Here I present two methods for unveiling rare diversity by integrating species presence/absence data from museum collections and the literature with quantitative estimates of species richness and abundance gathered from field-based bulk samples. Combining museum, literature, and field data can provide a more comprehensive estimate of taxonomic richness and abundance without substantial increase in current sampling effort. First, in a given bulk sample, the lowest proportional abundance value observed can be used to estimate the maximum abundance of rare species known to have occurred at the locality at least once but not recorded in the current sample. Second, a model-selection approach can be used, in which a set of relative abundance distribution models are fit to the bulk-sample abundance data and the parameter estimates for the best model used to calculate the abundance distribution for all species known from the locality. The Paleogene marine fossil record of the U.S. Gulf Coastal Plain is suitable for applying these methods, because (1) the molluscan fauna is well represented in museum collections and the literature, (2) the molluscan fauna has been taxonomically standardized, and (3) many classic localities remain accessible for standardized bulk sampling. I introduce these methods by applying them to a single locality and then, using the faunas of the Gosport, Moodys Branch, and Red Bluff Formations, I demonstrate how the model-fitting approach can be used to compare taxonomic richness among multiple localities. A substantial fraction of the molluscan richness known from each locality is not captured in bulk samples and much of this unobserved richness may be attributed to the rarity of species. The multiple-locality comparison suggests that the greatest Paleogene decline in standing richness occurred in the middle Eocene and that the recovery of richness following the Eocene-Oligocene extinction was quite rapid despite substantial loss of taxa. These analyses underscore the magnitude of veiled diversity in marine fossil assemblages and the potential of existing sources of data to unveil rare taxa, allowing them to be incorporated into quantitative diversity studies.", "keyphrases": ["rare diversity", "museum", "literature"]}
{"id": "10.1146/annurev-marine-010213-135144", "title": "Whale-fall ecosystems: recent insights into ecology, paleoecology, and evolution.", "abstract": "Whale falls produce remarkable organic- and sulfide-rich habitat islands at the seafloor. The past decade has seen a dramatic increase in studies of modern and fossil whale remains, yielding exciting new insights into whale-fall ecosystems. Giant body sizes and especially high bone-lipid content allow great-whale carcasses to support a sequence of heterotrophic and chemosynthetic microbial assemblages in the energy-poor deep sea. Deep-sea metazoan communities at whale falls pass through a series of overlapping successional stages that vary with carcass size, water depth, and environmental conditions. These metazoan communities contain many new species and evolutionary novelties, including bone-eating worms and snails and a diversity of grazers on sulfur bacteria. Molecular and paleoecological studies suggest that whale falls have served as hot spots of adaptive radiation for a specialized fauna; they have also provided evolutionary stepping stones for vent and seep mussels and could have facilitated speciation in other vent/seep taxa.", "keyphrases": ["habitat island", "great-whale carcass", "microbial assemblage", "deep sea", "whale-fall ecosystem"]}
{"id": "10.1080/03115518.2015.993299", "title": "A new palaeodictyopteroid (Megasecoptera: Brodiopteridae) from the Early Pennsylvanian of northern China reveals unique morphological traits and intra-specific variability", "abstract": "Pecharov\u00e1, M., Ren, D. & Prokop, J., 29.01.2015. A new palaeodictyopteroid (Megasecoptera: Brodiopteridae) from the Early Pennsylvanian of northern China reveals unique morphological traits and intra-specific variability. Alcheringa 39, XXX\u2013XXX. ISSN 0311-5518 Evaluation of abundant insect fossils from the Early Pennsylvanian (Namurian) Tupo Formation of northern China (Xiaheyan locality, Ningxia Hui Autonomous Region) enabled description of a new megasecopteran, i.e., Brodioptera sinensis sp. nov. and emendation of Brodiopteridae. Brodioptera sinensis is defined principally on wing venation characters and darkly pigmented wing apices, but a few have hyaline wing membranes possibly reflecting freshly emerged imagoes or subimagoes without fully developed coloration. The large assemblage of 54 specimens enabled documentation of intra-specific variability in wing venation. In addition, the new species reveals the detailed morphology of the haustellate mouthparts with conspicuous elongated stylets, and external copulatory organs that, previously, were poorly documented or unknown. The male and female external genitalia are similar to members of Protohymenidae (Megasecoptera) and Asthenohymenidae (Diaphanopterodea). Brodioptera sinensis is related to Brodioptera stricklani and Brodioptera cumberlandensis both known from localities in Euramerica suggesting faunal exchange occurred during the Bashkirian. Moreover, based on our analysis of veinal characters and re-examination of the holotype of Sylvohymen pintoi Brauckmann known from Namurian of Hagen-Vorhalle (Germany), we propose transferring this taxon to Brodiopteridae as Brodioptera pintoi comb. nov. Despite the different palaeoclimatic conditions in Euroamerica and Gondwanaland, we assume that Brodiopteridae are closely related to Xenopteridae (type genus: Xenoptera) known solely from South America because these groups have similar venation patterns and were contemporaneous. Martina Pecharov\u00e1 [martina.pecharova@natur.cuni.cz] Charles University in Prague, Faculty of Science, Department of Zoology, Vini\u010dn\u00e1 7, CZ-128 44, Praha 2, Czech Republic; Dong Ren [rendong@mail.cnu.edu.cn] Key Lab of Insect Evolution & Environmental Changes, College of Life Science, Capital Normal University, Beijing 100048, PR China; Jakub Prokop [jprokop@natur.cuni.cz] Charles University in Prague, Faculty of Science, Department of Zoology, Vini\u010dn\u00e1 7, CZ-128 44, Praha 2, Czech Republic.", "keyphrases": ["new palaeodictyopteroid", "brodiopteridae", "unique morphological trait"]}
{"id": "paleo.011915", "title": "Morphological Evolution Is Accelerated among Island Mammals", "abstract": "Dramatic evolutionary changes occur in species isolated on islands, but it is not known if the rate of evolution is accelerated on islands relative to the mainland. Based on an extensive review of the literature, I used the fossil record combined with data from living species to test the hypothesis of an accelerated morphological evolution among island mammals. I demonstrate that rates of morphological evolution are significantly greater\u2014up to a factor of 3.1\u2014for islands than for mainland mammal populations. The tendency for faster evolution on islands holds over relatively short time scales\u2014from a few decades up to several thousands of years\u2014but not over larger ones\u2014up to 12 million y. These analyses form the first empirical test of the long held supposition of accelerated evolution among island mammals. Moreover, this result shows that mammal species have the intrinsic capacity to evolve faster when confronted with a rapid change in their environment. This finding is relevant to our understanding of species' responses to isolation and destruction of natural habitats within the current context of rapid climate warming.", "keyphrases": ["mainland", "literature", "environment", "morphological evolution"]}
{"id": "10.1111/ele.12485", "title": "Ecological interactions on macroevolutionary time scales: clams and brachiopods are more than ships that pass in the night.", "abstract": "Competition among organisms has ecological and evolutionary consequences. However, whether the consequences of competition are manifested and measureable on macroevolutionary time scales is equivocal. Marine bivalves and brachiopods have overlapping niches such that competition for food and space may occur. Moreover, there is a long-standing debate over whether bivalves outcompeted brachiopods evolutionarily, because brachiopod diversity declined through time while bivalve diversity increased. To answer this question, we estimate the origination and extinction dynamics of fossil marine bivalve and brachiopod genera from the Ordovician through to the Recent while simultaneously accounting for incomplete sampling. Then, using stochastic differential equations, we assess statistical relationships among diversification and sampling dynamics of brachiopods and bivalves and five paleoenvironmental proxies. None of these potential environmental drivers had any detectable influence on brachiopod or bivalve diversification. In contrast, elevated bivalve extinction rates causally increased brachiopod origination rates, suggesting that bivalves have suppressed brachiopod evolution.", "keyphrases": ["macroevolutionary time scale", "brachiopod", "bivalve", "extinction rate", "ecological interaction"]}
{"id": "10.1126/science.abc5654", "title": "Using paleo-archives to safeguard biodiversity under climate change", "abstract": "Using the past to inform the future The late Quaternary paleorecord, within the past \u223c130,000 years, can help to inform present-day management of the Earth's ecosystems and biota under climate change. Fordham et al. review when and where rapid climate transitions can be found in the paleoclimate record. They show how such events in Earth's history can shape our understanding of the consequences of future global warming, including rates of biodiversity loss, changes in ecosystem structure and function, and degradation in the goods and services that these ecosystems provide to humanity. They also highlight how recent developments at the intersection of paleoecology, paleoclimatology, and macroecology can provide opportunities to anticipate and manage the responses of species and ecosystems to changing climates in the Anthropocene. Science, this issue p. eabc5654 BACKGROUND Effects of recent global warming have been documented in every biome on Earth. Safeguarding biodiversity and ecosystem services against future impacts requires reliable predictions of climate-driven biological responses and effective solutions. Integrated research in paleoecology, paleogenomics, paleoclimatology, and macroecology offers new prospects for projecting and managing current biotic responses to climate change. By revealing mechanisms that shaped past and present biodiversity patterns, this interdisciplinary intersection provides an empirical foundation for anticipating responses to accelerated climate change. New insights are coming from developments in high-throughput sequencing, computational technologies, ecological simulation models, and increased spatiotemporal resolution of paleoenvironmental data from late Quaternary paleo-records (the past ~130,000 years). Although these advances reveal biodiversity responses to past global change, benefits for improving forecasting of biodiversity impacts and refining conservation policies are lagging. Abundant opportunities exist for using the late Quaternary paleo-record to inform conservation practices and policies in the context of climate change. ADVANCES The threat of anthropogenic climate change demands that conservationists seek more effective ways of improving management of biodiversity and ecosystems. Analytical approaches that combine high-resolution paleoclimate proxy and simulation data, precisely dated fossils, and genetic diversity estimates from ancient DNA are unveiling biotic responses to various rates and magnitudes of natural climate warming, some comparable with 21st century projections. Reference periods in Earth\u2019s history provide natural laboratories for testing fundamental ecological theory and offer opportunities to identify ecological processes that influence the likelihood of extinction and ecosystem change, to test efficacy of threatened-species assessments and resilience of biota during periods of abrupt warming, and to locate biogeographic areas that remain stable under shifting climates. Refinement of essential biodiversity variables by using past biodiversity dynamics will improve our understanding of climate-driven shifts in species populations, community composition, and ecosystem structure and function. From this, biodiversity early-warning systems, conservation strategies, and decision-making tools can be tested at fine-grain spatiotemporal scales, providing an evidence base for understanding and improving projections of species- and ecosystem-level collapse. OUTLOOK As paleo-archives become more routinely integrated into conservation science, guidelines for the management of nature will benefit from understanding how different spatiotemporal scales of past climate change affected species and ecosystems across the planet. This will require global initiatives to harmonize vast numbers of paleoclimate-proxy and paleoecological records with high-resolution paleoclimate projections from Earth system models. Paleoecological data offer a means to disentangle climate and nonclimate drivers of biodiversity and ecosystem function, particularly in concert with simulation models and integrated analytical techniques that compare biotic change across regions with contrasting histories of human colonization and land use. Moreover, developments in paleogenomics that pinpoint adaptation across and within species will identify microevolutionary processes that lend resilience to biodiversity in shifting climates. Incorporating paleo-archives in conservation policies will equip decision-makers with improved strategies for mitigating biodiversity loss from climate change in the Anthropocene. Paleo-archives offer new prospects for benchmarking and maintaining future biodiversity. Integrated research using paleo-archives provides empirical foundations for contextualizing climate-driven changes in species populations, community composition, and ecosystem structure and function. These observations can inform conservation strategies under anthropogenic climate change. CREDITS: HUNG CHUNG CHIH, WANG LIQIANG, ANDREI STEPANOV, AUSTRALIANCAMERA, ALHOVIK, BLUERING MEDIA, NAZARII M, ANDERS SVENSSON/ SHUTTERSTOCK Strategies for 21st-century environmental management and conservation under global change require a strong understanding of the biological mechanisms that mediate responses to climate- and human-driven change to successfully mitigate range contractions, extinctions, and the degradation of ecosystem services. Biodiversity responses to past rapid warming events can be followed in situ and over extended periods, using cross-disciplinary approaches that provide cost-effective and scalable information for species\u2019 conservation and the maintenance of resilient ecosystems in many bioregions. Beyond the intrinsic knowledge gain such integrative research will increasingly provide the context, tools, and relevant case studies to assist in mitigating climate-driven biodiversity losses in the 21st century and beyond.", "keyphrases": ["paleo-archive", "biodiversity", "climate change"]}
{"id": "10.1029/2009PA001772", "title": "Freshwater input and abrupt deglacial climate change in the North Atlantic", "abstract": "Greenland ice-core records indicate that the last deglaciation (~7 - 21 ka) was punctuated by numerous abrupt climate reversals, involving temperature changes \r\nof up to 5-10oC within decades. However the cause behind many of these events is uncertain. A likely candidate may have been the input of deglacial meltwater, from the Laurentide ice sheet (LIS), to the high latitude North Atlantic, which disrupted ocean circulation and triggered cooling. Yet the direct evidence of meltwater input for many of these event has so far remained undetected. In this study, we use the geochemistry (paired Mg/Ca-\u03b418\r\nO) of planktonic foraminifera from a sediment core south of Iceland to reconstruct the input of freshwater to the \r\nnorthern North Atlantic during abrupt deglacial climate change. Our record can be placed on the same timescale as ice-cores and therefore provides a direct comparison between the timing of freshwater input and climate variability. Meltwater events coincide with the onset of numerous cold intervals, including the Older Dryas (14.0 ka), two events during the Allerod (at ~13.1 and 13.6 ka), the Younger Dryas (12.9 ka), and the 8.2 ka event, supporting a causal link between these abrupt climate changes and meltwater input. During the Bolling-Allerod \r\nwarm interval, we find that periods of warming are associated with an increased meltwater flux to the northern North Atlantic, which in turn induces abrupt cooling, a cessation in meltwater input, and eventual climate recovery. This implies that feedback between climate and meltwater input produced a highly variable climate. A comparison to published data sets suggests that this feedback likely included fluctuations in the southern margin of the LIS causing rerouting of LIS meltwater between southern and eastern drainage outlets, as proposed by Clark et al. [Science, 2001, v293, 283-287].", "keyphrases": ["deglacial climate change", "north atlantic", "freshwater input"]}
{"id": "10.7183/0002-7316.79.4.193", "title": "Bone Surface Modifications, Reasonable Certainty, and Human Antiquity in the Americas: The Case of the Arroyo Del Vizca\u03afno Site", "abstract": "Abstract Modifications on bone surfaces are taphonomic features that allow, among other aspects of environmental reconstruction, the assessment of human presence. The agents that cause such marks are diverse and of both biotic and abiotic origin. Among the former, marks made by human tools are of paramount importance for archaeologists and paleontologists to identify. Although it is possible to erroneously assign trampling marks to cut marks, several criteria have been recently developed so as to avoid such risks. These methods are applied here to the 30,000-year-old site of Arroyo del Vizca\u00edno (Uruguay), where over one thousand megafaunal remains have been collected. Some of them show marks that have been interpreted to be the result of the action of human tools. Using a database built up from previous studies of experimentally made marks as an actualistic model, it was concluded that the marks in the Arroyo del Vizca\u00edno site are unlikely to have been made by trampling, hence leaving human agency as the most feasible cause. This has important consequences for the debate on the human peopling of the Americas and on the process of extinction of the Pleistocene megafauna.", "keyphrases": ["americas", "human presence", "uruguay"]}
{"id": "10.1371/journal.pone.0018304", "title": "Inferences of Diplodocoid (Sauropoda: Dinosauria) Feeding Behavior from Snout Shape and Microwear Analyses", "abstract": "Background As gigantic herbivores, sauropod dinosaurs were among the most important members of Mesozoic communities. Understanding their ecology is fundamental to developing a complete picture of Jurassic and Cretaceous food webs. One group of sauropods in particular, Diplodocoidea, has long been a source of debate with regard to what and how they ate. Because of their long lineage duration (Late Jurassic-Late Cretaceous) and cosmopolitan distribution, diplodocoids formed important parts of multiple ecosystems. Additionally, fortuitous preservation of a large proportion of cranial elements makes them an ideal clade in which to examine feeding behavior. Methodology/Principal Findings Hypotheses of various browsing behaviors (selective and nonselective browsing at ground-height, mid-height, or in the upper canopy) were examined using snout shape (square vs. round) and dental microwear. The square snouts, large proportion of pits, and fine subparallel scratches in Apatosaurus, Diplodocus, Nigersaurus, and Rebbachisaurus suggest ground-height nonselective browsing; the narrow snouts of Dicraeosaurus, Suuwassea, and Tornieria and the coarse scratches and gouges on the teeth of Dicraeosaurus suggest mid-height selective browsing in those taxa. Comparison with outgroups (Camarasaurus and Brachiosaurus) reinforces the inferences of ground- and mid-height browsing and the existence of both non-selective and selective browsing behaviors in diplodocoids. Conclusions/Significance These results reaffirm previous work suggesting the presence of diverse feeding strategies in sauropods and provide solid evidence for two different feeding behaviors in Diplodocoidea. These feeding behaviors can subsequently be tied to paleoecology, such that non-selective, ground-height behaviors are restricted to open, savanna-type environments. Selective browsing behaviors are known from multiple sauropod clades and were practiced in multiple environments.", "keyphrases": ["diplodocoid", "behavior", "snout shape", "sauropod", "ecosystem"]}
{"id": "10.7717/peerj.5779", "title": "Cancellous bone and theropod dinosaur locomotion. Part II\u2014a new approach to inferring posture and locomotor biomechanics in extinct tetrapod vertebrates", "abstract": "This paper is the second of a three-part series that investigates the architecture of cancellous bone in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is widely known to be highly sensitive to its mechanical environment, and therefore has the potential to provide insight into locomotor biomechanics in extinct tetrapod vertebrates such as dinosaurs. Here in Part II, a new biomechanical modelling approach is outlined, one which mechanistically links cancellous bone architectural patterns with three-dimensional musculoskeletal and finite element modelling of the hindlimb. In particular, the architecture of cancellous bone is used to derive a single \u2018characteristic posture\u2019 for a given species\u2014one in which bone continuum-level principal stresses best align with cancellous bone fabric\u2014and thereby clarify hindlimb locomotor biomechanics. The quasi-static approach was validated for an extant theropod, the chicken, and is shown to provide a good estimate of limb posture at around mid-stance. It also provides reasonable predictions of bone loading mechanics, especially for the proximal hindlimb, and also provides a broadly accurate assessment of muscle recruitment insofar as limb stabilization is concerned. In addition to being useful for better understanding locomotor biomechanics in extant species, the approach hence provides a new avenue by which to analyse, test and refine palaeobiomechanical hypotheses, not just for extinct theropods, but potentially many other extinct tetrapod groups as well.", "keyphrases": ["locomotor biomechanic", "tetrapod vertebrate", "cancellous bone"]}
{"id": "10.1666/12001", "title": "Cats in the forest: predicting habitat adaptations from humerus morphometry in extant and fossil Felidae (Carnivora)", "abstract": "Abstract Mammalian carnivores are rarely incorporated in paleoenvironmental reconstructions, largely because of their rarity within the fossil record. However, multivariate statistical modeling can be successfully used to quantify specific anatomical features as environmental predictors. Here we explore morphological variability of the humerus in a closely related group of predators (Felidae) to investigate the relationship between morphometric descriptors and habitat categories. We analyze linear measurements of the humerus in three different morphometric combinations (log-transformed, size-free, and ratio), and explore four distinct ways of categorizing habitat adaptations. Open, Mixed, and Closed categories are defined according to criteria based on traditional descriptions of species, distributions, and biome occupancy. Extensive exploratory work is presented using linear discriminant analyses and several fossils are included to provide paleoecological reconstructions. We found no significant differences in the predictive power of distinct morphometric descriptors or habitat criteria, although sample splitting into small and large cat guilds greatly improves the stability of the models. Significant insights emerge for three long-canine cats: Smilodon populator, Paramachairodus orientalis, and Dinofelis sp. from Olduvai Gorge (East Africa). S. populator and P. orientalis are both predicted to have been closed-habitat adapted taxa. The false \u201csabertooth\u201d Dinofelis sp. from Olduvai Gorge is predicted to be adapted to mixed habitat. The application of felid humerus ecomorphology to the carnivoran record of Olduvai Gorge shows that the older stratigraphic levels (Bed I, 1.99\u20131.79 Ma) included a broader range of environments than Beds II or V, where there is an abundance of cats adapted to open environments.", "keyphrases": ["habitat adaptation", "felidae", "mammalian carnivore", "morphological variability", "cat"]}
{"id": "10.1111/j.1096-3642.2009.00505.x", "title": "Devonian actinopterygian phylogeny and evolution based on a redescription of Stegotrachelus finlayi", "abstract": "Basal actinopterygian phylogeny is in a state of flux. Discoveries of new Devonian and Carboniferous taxa have not only contributed to our knowledge of these animals, but have also complicated our understanding of their interrelationships. Over the preceding 50 years, there have been several new discoveries and redescriptions of early actinopterygians; however, Tegeolepis clarki, Kentuckia hlavini, and Stegotrachelus finlayi have never been fully redescribed. Although previous authors have re-examined the skull of S. finlayi, new material has recently been collected, in 1973 and 2002. This study synthesizes information from original and new material to fully redescribe S. finlayi, and incorporates these data into a cladistic analysis that examines the interrelationships of early actinopterygians. Phylogenetic systematic data returned support for a monophyletic Stegotrachelidae \u2013 an evolutionary systematic hypothesis generated over 40 years ago. Previous palaeoenvironmental and biogeographic hypotheses were tested, with results supporting the independent freshwater origins of several Devonian actinopts, although a regional endemic grade of Gondwanan taxa is not confirmed.", "keyphrases": ["actinopterygian phylogeny", "redescription", "stegotrachelus finlayi"]}
{"id": "10.1093/sysbio/34.3.280", "title": "The Ontogenetic Method for Determining Character Polarity and its Relevance to Phylogenetic Systematics", "abstract": "In an attempt to clarify the relevance of ontogenetic transformations for system\u00ad atics, the ontogenetic method for determining character polarity (the biogenetic law of Nelson, 1978) is analyzed from the perspective of phylogenetic systematics. In phylogenetic systematics, as defined here, the relationships sought are those of common ancestry and, thus, the concept of phylogeny is taken as an axiom from which systematic methods are deduced. This perspective has a number of consequences concerning the role of ontogenetic transformations in system\u00ad atics, among which are the following: (1) Von Baer's second law, which states that less general characters are developed from the most general, is not universally true. (2) The validity of Nelson's biogenetic law (not to be confused with other concepts of similar name) does not depend on the validity of von Baer's law. (3) As a theory about the relationship between on\u00ad togeny and phylogeny, Nelson's biogenetic law can only be tested by known character phylog\u00ad enies. However, outgroup, paleontological, and ontogenetic methods of polarity determination need not be interpreted as scientific theories; instead, they can be interpreted as theorems deduced from the axiom of phylogeny and certain auxiliary assumptions. (4) The usefulness of the ontogenetic method rests on an assumption of ancestral character retention. If ancestral characters are retained in descendant ontogenies, then ancestral characters will be more general than their phylogenetic derivatives. (5) The sequence of ontogenetic transformation is irrelevant to the usefulness of the ontogenetic method; generality is the critical factor. (6) An \"ontoge\u00ad netic\" method based on generality may be useful for determining evolutionary polarity when characters are instantaneous morphologies, but ontogenetic transformations rather than instan\u00ad taneous morphologies are more appropriately considered characters when attempting to deter\u00ad mine phylogenetic relationships among organisms. When ontogenetic transformations are viewed as characters, there can be no ontogenetic method for determining evolutionary character po\u00ad larity; however, the comparative phylogenetic method properly involves a comparison of on\u00ad togenetic transformations. (7) Ontogenetic polarities are different than phylogenetic polarities; the two have the relationship of part to whole, respectively. (8) For characters that exhibit ontogenetic transformation, homology is distinct from synapomorphy. (9) Finally, there is no threefold parallelism in phylogenetic systematics. Comparative anatomy, paleontology, and em\u00ad bryology are not three separate disciplines within systematics; rather, the three form a single comparative method unified in the organism by the concept of evolution. (Biogenetic law; von Baer's law; cladistics; character; evolution; generality; homology; ontogenetic method; ontogeny; outgroup method; paedomorphosis; parsimony; paleontological method; phylogenetic system\u00ad atics; phylogeny; polarity; semaphoront; synapomorphy; threefold parallelism.)", "keyphrases": ["ontogenetic method", "relevance", "phylogenetic systematic"]}
{"id": "paleo.002181", "title": "Diversity and disparity of sparassodonts (Metatheria) reveal non-analogue nature of ancient South American mammalian carnivore guilds", "abstract": "This study investigates whether terrestrial mammalian carnivore guilds of ancient South America, which developed in relative isolation, were similar to those of other continents. We do so through analyses of clade diversification, ecomorphology and guild structure in the Sparassodonta, metatherians that were the predominant mammalian carnivores of pre-Pleistocene South America. Body mass and 16 characters of the dentition are used to quantify morphological diversity (disparity) in sparassodonts and to compare them to extant marsupial and placental carnivores and extinct North American carnivoramorphans. We also compare trophic diversity of the Early Miocene terrestrial carnivore guild of Santa Cruz, Argentina to that of 14 modern and fossil guilds from other continents. We find that sparassodonts had comparatively low ecomorphological disparity throughout their history and that South American carnivore palaeoguilds, as represented by that of Santa Cruz, Argentina, were unlike modern or fossil carnivore guilds of other continents in their lack of mesocarnivores and hypocarnivores. Our results add to a growing body of evidence highlighting non-analogue aspects of extinct South American mammals and illustrate the dramatic effects that historical contingency can have on the evolution of mammalian palaeocommunities.", "keyphrases": ["sparassodont", "mammalian carnivore guild", "metatherian", "body mass"]}
{"id": "10.1080/02724634.2010.521606", "title": "Neurotrichus skoczeni, New Name for Neurotrichus minor Skoczen, 1993, Preoccupied", "abstract": "Skoczen (1993) described the fossil shrew-mole Neurotrichus minor on the basis of an Ml and a humerus from the Pliocene (MN 15/16) Polish locality of Weze 2. Popov (2004) has since transferred this species to Quyania, but Rzebik-Kowalska (2005) retained it in Neurotrichus. However, Dalquest and Burgner (1941) had already described the extant subspecies Neurotrichus gihhsii minor from western Washington; this form is still consid ered a valid subspecies found in coastal Washington and nearby British Columbia (Carraway and Verts, 1991; Hutterer, 2005). Regardless of the generic placement of N. minor Skoczen, the name is a primary homonym and permanently invalid (ICZN 1999:art. 57.2). Therefore, I propose the replacement name Neu rotrichus skoczeni, new name, for Neurotrichus minor Skoczen, 1993, preoccupied by Neurotrichus gibbsii minor Dalquest and Burgner, 1941. The specific name honors Stanislaw Skoczen, the original describer of the species, who passed away in 2007. The diagnosis, type locality, and holotype are as given by Skoczen (1993). I discovered the homonymy during work on the Neogene Old World (NOW) paleontological database.", "keyphrases": ["new name", "minor skoczen", "neurotrichus"]}
{"id": "10.1002/2015PA002820", "title": "Global change across the Oligocene-Miocene transition : High-resolution stable isotope records from IODP Site U1334 (equatorial Pacific Ocean)", "abstract": "The Oligocene-Miocene transition (OMT) (~23?Ma) is interpreted as a transient global cooling event, associated with a large-scale Antarctic ice sheet expansion. Here we present a 2.23?Myr long high-resolution (~3?kyr) benthic foraminiferal oxygen and carbon isotope (?18O and ?13C) record from Integrated Ocean Drilling Program Site U1334 (eastern equatorial Pacific Ocean), covering the interval from 21.91 to 24.14?Ma. To date, five other high-resolution benthic foraminiferal stable isotope stratigraphies across this time interval have been published, showing a ~1\u2030 increase in benthic foraminiferal ?18O across the OMT. However, these records are still few and spatially limited and no clear understanding exists of the global versus local imprints. We show that trends and the amplitudes of change are similar at Site U1334 as in other high-resolution stable isotope records, suggesting that these represent global deep water signals. We create a benthic foraminiferal stable isotope stack across the OMT by combining Site U1334 with records from ODP Sites 926, 929, 1090, 1264, and 1218 to best approximate the global signal. We find that isotopic gradients between sites indicate interbasinal and intrabasinal variabilities in deep water masses and, in particular, note an offset between the equatorial Atlantic and the equatorial Pacific, suggesting that a distinct temperature gradient was present during the OMT between these deep water masses at low latitudes. A convergence in the ?18O values between infaunal and epifaunal species occurs between 22.8 and 23.2?Ma, associated with the maximum ?18O excursion at the OMT, suggesting climatic changes associated with the OMT had an effect on interspecies offsets of benthic foraminifera. Our data indicate a maximum glacioeustatic sea level change of ~50?m across the OMT.", "keyphrases": ["oligocene-miocene transition", "stable isotope record", "equatorial pacific ocean"]}
{"id": "10.1017/RDC.2018.48", "title": "OSL and AMS 14C Age of the Most Complete Mammoth Fossil Skeleton from Northeastern China and its Paleoclimate Significance", "abstract": "ABSTRACT Applying radiocarbon (14C) dating using accelerator mass spectrometry (AMS) to the skeleton of a mammoth and the associated plant remains have been dated. The fossil of Zhalai Nur mammoth was dated to 43,500 +1000/\u2013900 14C yr BP. The results of optically stimulated luminescence (OSL) dating, which show that a fluvially deposited gravel layer, from that the mammoth fossils were excavated, formed between 51,300\u00b12100 and 26,600\u00b11200 yr BP, place the new AMS 14C dates in a well-developed chronological framework. Through this study, it can be summarized that, firstly, using suitable sample material, it is possible to obtain reliable AMS 14C results, even when the ages of the target materials approach the upper limits of the method. Second, it reveals that a depositional hiatus exists during the Late Pleistocene, between ca. 26,000 yr BP and ca. 13,000 yr BP. Finally, large rivers and widely distributed areas of alluvial-fluvial deposits existed in this present-day desert area between ca. 51,000 and 26,000 yr BP. These results may shed new light on the study of the Mammuthus-Colelodonta-Bubalus fauna, the most important and fully developed fauna during the Late Pleistocene in northeastern China. They also deepen our understanding about the eco-environments of the region.", "keyphrases": ["northeastern china", "late pleistocene", "osl"]}
{"id": "10.5194/bg-14-827-2017", "title": "Factors controlling the depth habitat of planktonic foraminifera in the subtropical eastern North Atlantic", "abstract": "Abstract. Planktonic foraminifera preserved in marine sediments archive the physical and chemical conditions under which they built their shells. To interpret the paleoceanographic information contained in fossil foraminifera, the recorded proxy signals have to be attributed to the habitat and life cycle characteristics of individual species. Much of our knowledge on habitat depth is based on indirect methods, which reconstruct the depth at which the largest portion of the shell has been calcified. However, habitat depth can be best studied by direct observations in stratified plankton nets. Here we present a synthesis of living planktonic foraminifera abundance data in vertically resolved plankton net hauls taken in the eastern North Atlantic during 12 oceanographic campaigns between 1995 and 2012. Live (cytoplasm-bearing) specimens were counted for each depth interval and the vertical habitat at each station was expressed as average living depth (ALD). This allows us to differentiate species showing an ALD consistently in the upper 100\u202fm (e.g., Globigerinoides ruber white and pink), indicating a shallow habitat; species occurring from the surface to the subsurface (e.g., Globigerina bulloides, Globorotalia inflata, Globorotalia truncatulinoides); and species inhabiting the subsurface (e.g., Globorotalia scitula and Globorotalia hirsuta). For 17 species with variable ALD, we assessed whether their depth habitat at a given station could be predicted by mixed layer (ML) depth, temperature in the ML and chlorophyll\u00a0a concentration in the ML. The influence of seasonal and lunar cycle on the depth habitat was also tested using periodic regression. In 11 out of the 17 tested species, ALD variation appears to have a predictable component. All of the tested parameters were significant in at least one case, with both seasonal and lunar cyclicity as well as the environmental parameters explaining up to >\u202f50\u202f% of the variance. Thus, G. truncatulinoides, G. hirsuta and G. scitula appear to descend in the water column towards the summer, whereas populations of Trilobatus sacculifer appear to descend in the water column towards the new moon. In all other species, properties of the mixed layer explained more of the observed variance than the periodic models. Chlorophyll\u00a0a concentration seems least important for ALD, whilst shoaling of the habitat with deepening of the ML is observed most frequently. We observe both shoaling and deepening of species habitat with increasing temperature. Further, we observe that temperature and seawater density at the depth of the ALD were not equally variable among the studied species, and their variability showed no consistent relationship with depth habitat. According to our results, depth habitat of individual species changes in response to different environmental and ontogenetic factors and consequently planktonic foraminifera exhibit not only species-specific mean habitat depths but also species-specific changes in habitat depth.", "keyphrases": ["depth habitat", "planktonic foraminifera", "eastern north atlantic"]}
{"id": "paleo.000102", "title": "The Endocranial Anatomy of Therizinosauria and Its Implications for Sensory and Cognitive Function", "abstract": "Background Therizinosauria is one of the most enigmatic and peculiar clades among theropod dinosaurs, exhibiting an unusual suite of characters, such as lanceolate teeth, a rostral rhamphotheca, long manual claws, and a wide, opisthopubic pelvis. This specialized anatomy has been associated with a shift in dietary preferences and an adaptation to herbivory. Despite a large number of discoveries in recent years, the fossil record for Therizinosauria is still relatively poor, and cranial remains are particularly rare. Methodology/Principal Findings Based on computed tomographic (CT) scanning of the nearly complete and articulated skull of Erlikosaurus andrewsi, as well as partial braincases of two other therizinosaurian taxa, the endocranial anatomy is reconstructed and described. The wider phylogenetic range of the described specimens permits the evaluation of sensory and cognitive capabilities of Therizinosauria in an evolutionary context. The endocranial anatomy reveals a mosaic of plesiomorphic and derived characters in therizinosaurians. The anatomy of the olfactory apparatus and the endosseous labyrinth suggests that olfaction, hearing, and equilibrium were well-developed in therizinosaurians and might have affected or benefited from an enlarged telencephalon. Conclusion/Significance This study presents the first appraisal of the evolution of endocranial anatomy and sensory adaptations in Therizinosauria. Despite their phylogenetically basal position among maniraptoran dinosaurs, therizinosaurians had developed the neural pathways for a well developed sensory repertoire. In particular olfaction and hearing may have played an important role in foraging, predator evasion, and/or social complexity.", "keyphrases": ["endocranial anatomy", "anatomy", "therizinosauria", "theropod", "labyrinth"]}
{"id": "10.1093/zoolinnean/zlz025", "title": "Diabloroter bolti, a short-bodied recumbirostran \u2018microsaur\u2019 from the Francis Creek Shale, Mazon Creek, Illinois", "abstract": "The Carboniferous (Pennsylvanian; 309\u2013307 Mya) \u2018Mazon Creek\u2019 Lagerst\u00e4tte produces some of the earliest tetrapod fossils of major Palaeozoic lineages. Previously, the Mazon Creek record of \u2018microsaurs\u2019 was known from a single specimen. However, the lack of key anatomy, such as the skull, precluded a confident taxonomic assignment, thus only a suggested affinity to the microbrachimorph \u2018microsaur\u2019 Hyloplesion was determined. Recently several new tetrapod specimens collected from Mazon Creek have come to light, of which some have recumbirostran \u2018microsaur\u2019 affinity. Here we describe a new genus and species of short-bodied recumbirostran, Diabloroter bolti, on the basis of a unique combination of autapomorphies. Both parsimony and Bayesian phylogenetic methods recover the new taxon in the Brachystelechidae clade, as sister to a clade including Carrolla and Batropetes. We determine Diabloroter to be the earliest known member of Brachytelechidae and thus establishing a Carboniferous origin of the family. We also provide an updated diagnosis for Brachystelechidae. Finally, we comment on the evolutionary trends in the clade, including dental adaptations for a proposed algivorous diet in derived clade members.", "keyphrases": ["short-bodied recumbirostran", "recumbirostran", "microsaur", "tetrapod fossil"]}
{"id": "10.1002/hbm.25964", "title": "Sulci 3D mapping from human cranial endocasts: A powerful tool to study hominin brain evolution", "abstract": "Key questions in paleoneurology concern the timing and emergence of derived cerebral features within the human lineage. Endocasts are replicas of the internal table of the bony braincase that are widely used in paleoneurology as a proxy for reconstructing a timeline for hominin brain evolution in the fossil record. The accurate identification of cerebral sulci imprints in endocasts is critical for assessing the topographic extension and structural organisation of cortical regions in fossil hominins. High\u2010resolution imaging techniques combined with established methods based on population\u2010specific brain atlases offer new opportunities for tracking detailed endocranial characteristics. This study provides the first documentation of sulcal pattern imprints from the superolateral surface of the cerebrum using a population\u2010based atlas technique on extant human endocasts. Human crania from the Pretoria Bone Collection (South Africa) were scanned using micro\u2010CT. Endocasts were virtually extracted, and sulci were automatically detected and manually labelled. A density map method was applied to project all the labels onto an averaged endocast to visualise the mean distribution of each identified sulcal imprint. This method allowed for the visualisation of inter\u2010individual variation of sulcal imprints, for example, frontal lobe sulci, correlating with previous brain\u2010MRI studies and for the first time the extensive overlapping of imprints in historically debated areas of the endocast (e.g. occipital lobe). In providing an innovative, non\u2010invasive, observer\u2010independent method to investigate human endocranial structural organisation, our analytical protocol introduces a promising perspective for future research in paleoneurology and for discussing critical hypotheses on the evolution of cognitive abilities among hominins.", "keyphrases": ["endocast", "hominin brain evolution", "sulci"]}
{"id": "10.1111/gbi.12240", "title": "A geochemical study of the Ediacaran discoidal fossil Aspidella preserved in limestones: Implications for its taphonomy and paleoecology", "abstract": "The Ediacara biota features the rise of macroscopic complex life immediately before the Cambrian explosion. One of the most abundant and widely distributed elements of the Ediacara biota is the discoidal fossil Aspidella, which is interpreted as a subsurface holdfast possibly anchoring a frondose epibenthic organism. It is a morphologically simple fossil preserved mainly in siliciclastic rocks, which are unsuitable for comprehensive stable isotope geochemical analyses to decipher its taphonomy and paleoecology. In this regard, three\u2010dimensionally preserved Aspidella fossils from upper Ediacaran limestones of the Khatyspyt Formation in the Olenek Uplift of northern Siberia offer a rare opportunity to leverage geochemistry for insights into their taphonomy and paleoecology. To take advantage of this opportunity, we analyzed \u03b413Ccarb, \u03b418Ocarb, \u03b413Corg, \u03b434Spyr, and iron speciation of the Khatyspyt Aspidella fossils and surrounding sediment matrix in order to investigate whether they hosted microbial symbionts, how they were fossilized, and the redox conditions of their ecological environments. Aspidella holdfasts and surrounding sediment matrix show indistinguishable \u03b413Corg values, suggesting they did not host and derive significant amount of nutrients from microbial symbionts such as methanogens, methylotrophs, or sulfide\u2010oxidizing bacteria. \u03b413Ccarb, \u03b418Ocarb, and \u03b434Spyr data, along with petrographic observations, suggest that microbial sulfate reduction facilitated the preservation of Aspidella by promoting early authigenic calcite cementation in the holdfasts before matrix cementation and sediment compaction. Iron speciation data are equivocal, largely because of the low total iron concentrations. However, consideration of published sulfur isotope and biomarker data suggests that Aspidella likely lived in non\u2010euxinic waters. It is possible that Aspidella was an opportunistic organism, colonizing the seafloor in large numbers when paleoenvironments were favorable. This study demonstrates that geochemical data of Ediacaran fossils preserved in limestones can offer important insights into the taphonomy and paleoecology of these enigmatic organisms living on the eve of the Cambrian explosion.", "keyphrases": ["fossil aspidella", "limestone", "paleoecology"]}
{"id": "10.1177/0959683620981700", "title": "Sum things are not what they seem: Problems with point-wise interpretations and quantitative analyses of proxies based on aggregated radiocarbon dates", "abstract": "Radiocarbon-date assemblages are commonly used as proxies for past human and environmental phenomena. Prominent examples of target phenomena include past population levels and sea level fluctuations. These processes are thought to have affected the amount of organic carbon deposited into the archaeological and/or palaeoenvironmental record. Time-series representing through-time fluctuations in the frequency of radiocarbon samples are, therefore, often used as proxies for such processes. However, there are critical problems with using radiocarbon \u201cdates-as-data\u201d in point-wise comparisons and these problems have gone largely underappreciated. The key problem is that the established proxies are easily misinterpreted. They conflate process variation and chronological uncertainty, which makes them unsuitable for point-wise comparisons aimed at identifying rates of change, comparing variables directly, or estimating parameters in regression models. Here we explore the interpretive and analytical problems in detail in an effort to raise awareness and promote skepticism about the use of the established proxies in point-wise comparisons. We also provide suggestions for future research and point to potential methodological alternatives that may improve the viability of dates-as-data approaches.", "keyphrases": ["problem", "process variation", "chronological uncertainty"]}
{"id": "paleo.009472", "title": "Using Phylogenomic Data to Explore the Effects of Relaxed Clocks and Calibration Strategies on Divergence Time Estimation: Primates as a Test Case", "abstract": "Primates have long been a test case for the development of phylogenetic methods for divergence time estimation. Despite a large number of studies, however, the timing of origination of crown Primates relative to the K-Pg boundary and the timing of diversification of the main crown groups remain controversial. Here we analysed a dataset of 372 taxa (367 Primates and 5 outgroups, 61 thousand base pairs) that includes nine complete primate genomes (3.4 million base pairs). We systematically explore the effect of different interpretations of fossil calibrations and molecular clock models on primate divergence time estimates. We find that even small differences in the construction of fossil calibrations can have a noticeable impact on estimated divergence times, especially for the oldest nodes in the tree. Notably, choice of molecular rate model (auto-correlated or independently distributed rates) has an especially strong effect on estimated times, with the independent rates model producing considerably more ancient estimates for the deeper nodes in the phylogeny. We implement thermodynamic integration, combined with Gaussian quadrature, in the program MCMCTree, and use it to calculate Bayes factors for clock models. Bayesian model selection indicates that the auto-correlated rates model fits the primate data substantially better, and we conclude that time estimates under this model should be preferred. We show that for eight core nodes in the phylogeny, uncertainty in time estimates is close to the theoretical limit imposed by fossil uncertainties. Thus, these estimates are unlikely to be improved by collecting additional molecular sequence data. All analyses place the origin of Primates close to the K-Pg boundary, either in the Cretaceous or straddling the boundary into the Palaeogene.", "keyphrases": ["divergence time estimation", "primate", "test case", "fossil calibration", "node"]}
{"id": "10.26879/759", "title": "An exceptionally well-preserved skeleton of Thomashuxleya externa (Mammalia, Notoungulata), from the Eocene of Patagonia, Argentina", "abstract": "We describe one of the oldest notoungulate skeletons with associated craniodental and postcranial elements: Thomashuxleya externa (Isotemnidae) from Canadon Vaca in Patagonia, Argentina (Vacan subage of the Casamayoran SALMA, middle Eocene). We provide body mass estimates given by different elements of the skeleton, describe the bone histology, and study its phylogenetic position. We note differences in the scapulae, humerii, ulnae, and radii of the new specimen in comparison with other specimens previously referred to this taxon. We estimate a body mass of 84 \u00b1 24.2 kg, showing that notoungulates had acquired a large body mass by the middle Eocene. Bone histology shows that the new specimen was skeletally mature. The new material supports the placement of Thomashuxleya as an early, divergent member of Toxodontia. Among placentals, our phylogenetic analysis of a combined DNA, collagen, and morphology matrix favor only a limited number of possible phylogenetic relationships, but cannot yet arbitrate between potential affinities with Afrotheria or Laurasiatheria. With no constraint, maximum parsimony supports Thomashuxleya and Carodnia with Afrotheria. With Notoungulata and Litopterna constrained as monophyletic (including Macrauchenia and Toxodon known for collagens), these clades are reconstructed on the stem to Euungulata (i.e., Perissodactyla and Artiodactyla). Unconstrained, Bayesian analysis weakly supports the possibility that Thomashuxleya is a stem xenarthran; with Notoungulata and Litopterna constrained as monophyletic, the two clades are recovered as sister to Perissodactyla. Anatomical data sampled thus far for Thomashuxleya, combined with collagen amino acids for Pleistocene meridiungulates, substantially limit the number of possible affinities for endemic South American species among mammals, although ambiguity still remains.", "keyphrases": ["thomashuxleya externa", "notoungulata", "litopterna"]}
{"id": "10.1017/S0016756819000426", "title": "The trouble with trilobites: classification, phylogeny and the cryptogenesis problem", "abstract": "Abstract Trilobites are an iconic group of extinct arthropods that lived in Palaeozoic oceans for c. 270 Ma, before their demise at the end of the Permian Period. Despite their considerable diversity (> 22 000 species) and abundance, particularly in Cambrian and Ordovician rocks, as well as intensive study for well over 200 years, trilobite systematics remains in a state of flux. In this contribution, the complex history of trilobite classification over the last century is briefly reviewed, including the seminal scheme published by Henry Swinnerton in 1915. The cryptogenesis problem, which relates to the supposedly obscure phylogenetic links between major post-Cambrian trilobite clades and their Cambrian sister taxa, is also discussed. Previous studies have suggested that the cryptogenesis problem is largely a taxonomic artefact, but the Cambrian origins of some post-Cambrian groups, such as the orders Proetida and Odontopleurida, are still unclear. Future directions for research on trilobite systematics are outlined, from taxonomic studies involving comprehensive documentation and extensive illustration of morphology at the species level, through to broad-scale phylogenetic analyses that initiate or test hypotheses about relationships across the major groups. Other ongoing issues to be addressed include identifying the sister group of Trilobita, and determining whether certain taxa, such as the suborder Agnostina and Cambrian family Burlingiidae, represent trilobites.", "keyphrases": ["trilobite", "classification", "cryptogenesis problem"]}
{"id": "10.1073/pnas.1509491112", "title": "New model to explain tooth wear with implications for microwear formation and diet reconstruction", "abstract": "Significance Dental microwear is among the most common proxies paleontologists use for diet reconstruction. Recent models have suggested that while quartz grit adherent to food produces wear of tooth enamel, softer particles, such as silica phytoliths found in many plants, do not. Some have therefore suggested that microwear patterns better reflect habitat than diet. This is important to paleobiologists because reconstructions of species from the earliest vertebrates to human ancestors have relied on dental microwear as a proxy for diet. Here we present an in vitro study demonstrating that softer particles produce microwear under conditions mimicking chewing. Enamel wear occurs not because an abrasive is hard but because it exceeds the binding force of proteins that hold together hydroxyapatite crystallites. Paleoanthropologists and vertebrate paleontologists have for decades debated the etiology of tooth wear and its implications for understanding the diets of human ancestors and other extinct mammals. The debate has recently taken a twist, calling into question the efficacy of dental microwear to reveal diet. Some argue that endogenous abrasives in plants (opal phytoliths) are too soft to abrade enamel, and that tooth wear is caused principally by exogenous quartz grit on food. If so, variation in microwear among fossil species may relate more to habitat than diet. This has important implications for paleobiologists because microwear is a common proxy for diets of fossil species. Here we reexamine the notion that particles softer than enamel (e.g., silica phytoliths) do not wear teeth. We scored human enamel using a microfabrication instrument fitted with soft particles (aluminum and brass spheres) and an atomic force microscope (AFM) fitted with silica particles under fixed normal loads, sliding speeds, and spans. Resulting damage was measured by AFM, and morphology and composition of debris were determined by scanning electron microscopy with energy-dispersive X-ray spectroscopy. Enamel chips removed from the surface demonstrate that softer particles produce wear under conditions mimicking chewing. Previous models posited that such particles rub enamel and create ridges alongside indentations without tissue removal. We propose that although these models hold for deformable metal surfaces, enamel works differently. Hydroxyapatite crystallites are \u201cglued\u201d together by proteins, and tissue removal requires only that contact pressure be sufficient to break the bonds holding enamel together.", "keyphrases": ["tooth wear", "microwear", "diet reconstruction", "food", "aluminium"]}
{"id": "paleo.006204", "title": "Ups and downs of belemnite diversity in the Early Jurassic of Western Tethys", "abstract": "Although belemnites form a major clade of extinct cephalopods, the early stage of their diversification remains poorly known in time and space. Here we investigate the first diversification episodes of belemnites (order Belemnitida) using a new species\u2010level database encompassing the Hettangian\u2013Aalenian interval (Early Jurassic \u2013 earliest Middle Jurassic) and covering the Western Tethys. Rarefied richness shows a four\u2010fold increase from the Planorbis chronozone to the Ibex chronozone, a strong decrease between the Margaritatus and Spinatum chronozones, followed by a drop in the Spinatum\u2013Serpentinum interval that is coeval with the second\u2010order Toarcian biological crisis. The Bifrons chronozone records a high richness that departs significantly from those of the surrounding chronozones. A last richness peak in the Dispansum chronozone precedes a decrease towards the Aalenian. Biogeographical analyses do not reveal any clear large\u2010scale provincialism for belemnites, in sharp contrast with ammonoids. Such a long\u2010term homogeneous spatial distribution of belemnites is probably due to: (1) the relatively poorly\u2010documented fossil record of belemnites, especially in Mediterranean localities; and (2) contrasted dispersal abilities of belemnites compared to ammonoids over the studied time interval.", "keyphrases": ["belemnite", "jurassic", "western tethys", "margaritatus"]}
{"id": "paleo.004178", "title": "A new crown-group salamander from the Middle Jurassic of Western Siberia, Russia", "abstract": "A new crown-group salamander, Kiyatriton krasnolutskii sp. nov., from the Middle Jurassic (Bathonian) Itat Formation of the Berezovsk Quarry locality in Western Siberia, Russia, is described on the basis of new material and a dentary fragment previously referred to the undescribed salamander taxon BBerezovsk salamander B^(sensu Skutschas 2013). Kiyatriton krasnolutskii sp. nov. differs from K. leshchinskiyi (type species of the genus Kiyatriton) in that the ventrolateral ridges on the atlas are sharper anteriorly, more ventrally oriented and reach the anterior cotylar rims and that the dentary has a relatively taller dental parapet. Kiyatriton krasnolutskii sp. nov. is one of the oldest salamanders in the fossil record. The finding of Kiyatriton krasnolutskii sp. nov. in Berezovsk Quarry is significant for: (1) clarifying that the previously reported BBerezovsk salamander B^is a crown-group salamander of the genus Kiyatriton; (2) extending the stratigraphic range of the genus Kiyatriton backward some 40 million years into the Bathonian, from the previously youngest record in the Aptian-Albian; (3) indicating that K. leshchinskiyi from the Aptian-Albian Shestakovo locality in Western Siberia, Russia, survived as a relic into the Early Cretaceous of present-day Western Siberia; (4) supporting the hypothesis that Bathonian vertebrate faunas of Europe and Western Siberia were homogeneous; and (5) suggesting that all Bathonian crown-group salamanders in Asia could be members of one cryptobranchoid clade and could represent the first radiation of Cryptobranchoidea.", "keyphrases": ["new crown-group salamander", "western siberia", "berezovsk quarry locality"]}
{"id": "10.1098/rspb.2021.0393", "title": "Quantitative assessment of tarsal morphology illuminates locomotor behaviour in Palaeocene mammals following the end-Cretaceous mass extinction", "abstract": "Mammals exhibit vast ecological diversity, including a panoply of locomotor behaviours. The foundations of this diversity were established in the Mesozoic, but it was only after the end-Cretaceous mass extinction that mammals began to increase in body size, diversify into many new species and establish the extant orders. Little is known about the palaeobiology of the mammals that diversified immediately after the extinction during the Palaeocene, which are often perceived as \u2018archaic\u2019 precursors to extant orders. Here, we investigate the locomotor ecology of Palaeocene mammals using multivariate and disparity analyses. We show that tarsal measurements can be used to infer locomotor mode in extant mammals, and then demonstrate that Palaeocene mammals occupy distinctive regions of tarsal morphospace relative to Cretaceous and extant therian mammals, that is distinguished by their morphological robustness. We find that many Palaeocene species exhibit tarsal morphologies most comparable with morphologies of extant ground-dwelling mammals. Disparity analyses indicate that Palaeocene mammals attained similar morphospace diversity to the extant sample. Our results show that mammals underwent a post-extinction adaptive radiation in tarsal morphology relating to locomotor behaviour by combining a basic eutherian bauplan with anatomical specializations to attain considerable ecomorphological diversity.", "keyphrases": ["tarsal morphology", "locomotor behaviour", "palaeocene mammal"]}
{"id": "10.11646/zootaxa.3755.4.5", "title": "Glesirhanis bercioi, a new genus and species from Baltic amber (Coleoptera: Endomychidae: Leiestinae) with a checklist and nomenclatural notes regarding fossil Endomychidae.", "abstract": "A new genus and species of handsome fungus beetle, Glesirhanis bercioi gen. nov., sp. nov. (Coleoptera: Endomychidae: Leiestinae) is described from Baltic amber. The newly described genus is compared with all known extant and extinct genera of the subfamily. A key to the genera of Leiestinae including fossils and a checklist of fossil Endomychidae are provided. The status of two taxa previously placed in Endomychidae, Palaeoendomychus gymnus Zhang and Tetrameropsis mesozoica Kirejtshuk & Azar, is discussed, and a new status for the latter, elevating it to the family-level as Tetrameropseidae status nov., is proposed.", "keyphrases": ["new genus", "coleoptera", "fossil endomychidae"]}
{"id": "paleo.010778", "title": "Inferring locomotor behaviours in Miocene New World monkeys using finite element analysis, geometric morphometrics and machine-learning classification techniques applied to talar morphology", "abstract": "The talus is one of the most commonly preserved post-cranial elements in the platyrrhine fossil record. Talar morphology can provide information about postural adaptations because it is the anatomical structure responsible for transmitting body mass forces from the leg to the foot. The aim of this study is to test whether the locomotor behaviour of fossil Miocene platyrrhines could be inferred from their talus morphology. The extant sample was classified into three different locomotor categories and then talar strength was compared using finite-element analysis. Geometric morphometrics were used to quantify talar shape and to assess its association with biomechanical strength. Finally, several machine-learning (ML) algorithms were trained using both the biomechanical and morphometric data from the extant taxa to infer the possible locomotor behaviour of the Miocene fossil sample. The obtained results show that the different locomotor categories are distinguishable using either biomechanical or morphometric data. The ML algorithms categorized most of the fossil sample as arboreal quadrupeds. This study has shown that a combined approach can contribute to the understanding of platyrrhine talar morphology and its relationship with locomotion. This approach is likely to be beneficial for determining the locomotor habits in other fossil taxa.", "keyphrases": ["locomotor behaviour", "geometric morphometric", "talar morphology"]}
{"id": "10.1080/02724634.1994.10011564", "title": "Transformation of the quadrate (incus) through the transition from non-mammalian cynodonts to mammals", "abstract": "ABSTRACT The quadrate (incus) bone underwent important evolutionary transformations through the cynodont-mammal transition. The following character transformations played crucial roles in modifying the cynodont quadrate into the mammalian incus: 1) progressively greater rotation of the dorsal plate relative to the trochlea; 2) the contact facet of the dorsal plate becomes concave; 3) development of a constricted neck between the dorsal plate and the trochlea; 4) simplification of the quadrate-cranium joint, resulting in better mobility of the joint; and 5) introduction of a stapedial process (crus longum). The dorsal plate rotation, the concave contact facet, the constricted neck, the mobile joint of the quadrate and the cranium are also present in some advanced non-mammalian cynodonts. Broad phylogenetic distributions of these features suggest that the major features of the incus of early mammals, as represented by Morganucodon, originated much earlier in phylogenetic history among non-mammalian cynodont...", "keyphrases": ["quadrate", "incus", "non-mammalian cynodont", "cranium", "transformation"]}
{"id": "paleo.002816", "title": "Wear facets and enamel spalling in tyrannosaurid dinosaurs", "abstract": "Numerous paleontologists have noted wear facets on tyrannosaurid lateral teeth over the past century. While several workers have proposed explanations for these features, there remains to this day no consensus concerning their etiology.\nHere we report on an examination of wear surfaces on these teeth from the Upper Cretaceous (mid-Campanian) Judith River Group of southern Alberta, Canada. This study reveals two distinct types of wear features on the labial and lingual sides of tyrannosaurid lateral teeth: irregular \"spalled\" surfaces and wear facets. The irregular spalled surfaces typically extend to the apex of the tooth, which evidently reflects flaking of enamel resulting from forces produced during contact between tooth and food. These surfaces are often rounded, presumably from antemortem wear following spalling. Wear striations on these surfaces are oriented heterogeneously. The wear facets, in contrast, occur on only one side of the tooth and are typically elliptical in outline and evince parallel wear striations. Similar patterns of parallel wear striations in extant mammals reflect tooth-tooth contact. We therefore propose that wear facets in tyrannosaurids were formed by repeated tooth-tooth contact between the lingual side of maxillary teeth and labial side of dentary teeth. It remains unclear whether this contact was serendipitous or adaptive, though it appears to be unusual for reptiles, as we have found no evidence for wear facets in extant varanids and crocodilians.", "keyphrases": ["facet", "lingual side", "parallel wear striation", "dentary tooth"]}
{"id": "paleo.006911", "title": "Extinction of fish-shaped marine reptiles associated with reduced evolutionary rates and global environmental volatility", "abstract": "Despite their profound adaptations to the aquatic realm and their apparent success throughout the Triassic and the Jurassic, ichthyosaurs became extinct roughly 30 million years before the end-Cretaceous mass extinction. Current hypotheses for this early demise involve relatively minor biotic events, but are at odds with recent understanding of the ichthyosaur fossil record. Here, we show that ichthyosaurs maintained high but diminishing richness and disparity throughout the Early Cretaceous. The last ichthyosaurs are characterized by reduced rates of origination and phenotypic evolution and their elevated extinction rates correlate with increased environmental volatility. In addition, we find that ichthyosaurs suffered from a profound Early Cenomanian extinction that reduced their ecological diversity, likely contributing to their final extinction at the end of the Cenomanian. Our results support a growing body of evidence revealing that global environmental change resulted in a major, temporally staggered turnover event that profoundly reorganized marine ecosystems during the Cenomanian.", "keyphrases": ["marine reptile", "evolutionary rate", "environmental volatility", "ichthyosaur", "early triassic"]}
{"id": "10.1073/pnas.1100572108", "title": "Direct and indirect effects of biological factors on extinction risk in fossil bivalves", "abstract": "Biological factors, such as abundance and body size, may contribute directly to extinction risk and indirectly through their influence on other biological characteristics, such as geographic range size. Paleontological data can be used to explicitly test many of these hypothesized relationships, and general patterns revealed through analysis of the fossil record can help refine predictive models of extinction risk developed for extant species. Here, I use structural equation modeling to tease apart the contributions of three canonical predictors of extinction\u2014abundance, body size, and geographic range size\u2014to the duration of bivalve species in the early Cenozoic marine fossil record of the eastern United States. I find that geographic range size has a strong direct effect on extinction risk and that an apparent direct effect of abundance can be explained entirely by its covariation with geographic range. The influence of geographic range on extinction risk is manifest across three ecologically disparate bivalve clades. Body size also has strong direct effects on extinction risk but operates in opposing directions in different clades, and thus, it seems to be decoupled from extinction risk in bivalves as a whole. Although abundance does not directly predict extinction risk, I reveal weak indirect effects of both abundance and body size through their positive influence on geographic range size. Multivariate models that account for the pervasive covariation between biological factors and extinction are necessary for assessing causality in evolutionary processes and making informed predictions in applied conservation efforts.", "keyphrases": ["indirect effect", "biological factor", "extinction risk", "body size", "range size"]}
{"id": "10.1073/pnas.2019145118", "title": "Global hydroclimatic response to tropical volcanic eruptions over the last millennium", "abstract": "Significance Future large tropical volcanic eruptions will induce global hydroclimatic changes, superimposed on anthropogenic climate change. Understanding how volcanic eruptions affect global hydroclimate is therefore critically important. Tejedor et al. use a new paleoclimatic product, which combines information from high-resolution proxies and climate models, to estimate volcanic impacts on hydroclimate over the last millennium. They find that past eruptions caused severe drying in tropical Africa and across Central Asia and the Middle East and significantly wetter conditions over Oceania and the South American monsoon region, some of which persisted for a decade or longer. These proxy-based findings suggest that, relative to estimates from a state-of-the-art climate model, much larger and persistent hydroclimatic changes are possible across regions of important socioeconomic activity. Large tropical volcanic eruptions can affect the climate of many regions on Earth, yet it is uncertain how the largest eruptions over the past millennium may have altered Earth\u2019s hydroclimate. Here, we analyze the global hydroclimatic response to all the tropical volcanic eruptions over the past millennium that were larger than the Mount Pinatubo eruption of 1991. Using the Paleo Hydrodynamics Data Assimilation product (PHYDA), we find that these large volcanic eruptions tended to produce dry conditions over tropical Africa, Central Asia and the Middle East and wet conditions over much of Oceania and the South American monsoon region. These anomalies are statistically significant, and they persisted for more than a decade in some regions. The persistence of the anomalies is associated with southward shifts in the Intertropical Convergence Zone and sea surface temperature changes in the Pacific and Atlantic oceans. We compare the PHYDA results with the stand-alone model response of the Community Earth System Model (CESM)-Last Millennium Ensemble. We find that the proxy-constrained PHYDA estimates are larger and more persistent than the responses simulated by CESM. Understanding which of these estimates is more realistic is critical for accurately characterizing the hydroclimate risks of future volcanic eruptions.", "keyphrases": ["tropical volcanic eruption", "last millennium", "global hydroclimatic response"]}
{"id": "paleo.008141", "title": "Larval ecology and morphology in fossil gastropods", "abstract": "The shell of marine gastropods conserves and reflects early ontogeny, including embryonic and larval stages, to a high degree when compared with other marine invertebrates. Planktotrophic larval development is indicated by a small embryonic shell (size is also related to systematic placement) with little yolk followed by a multiwhorled shell formed by a free\u2010swimming veliger larva. Basal gastropod clades (e.g. Vetigastropoda) lack planktotrophic larval development. The great majority of Late Palaeozoic and Mesozoic \u2018derived\u2019 marine gastropods (Neritimorpha, Caenogastropoda and Heterobranchia) with known protoconch had planktotrophic larval development. Dimensions of internal moulds of protoconchs suggest that planktotrophic larval development was largely absent in the Cambrian and evolved at the Cambrian\u2013Ordovician transition, mainly due to increasing benthic predation. The evolution of planktotrophic larval development offered advantages and opportunities such as more effective dispersal, enhanced gene flow between populations and prevention of inbreeding. Early gastropod larval shells were openly coiled and weakly sculptured. During the Mid\u2010 and Late Palaeozoic, modern tightly coiled larval shells (commonly with strong sculpture) evolved due to increasing predation pressure in the plankton. The presence of numerous Late Palaeozoic and Triassic gastropod species with planktotrophic larval development suggests sufficient primary production although direct evidence for phytoplankton is scarce in this period. Contrary to previous suggestions, it seems unlikely that the end\u2010Permian mass extinction selected against species with planktotrophic larval development. The molluscan classes with highest species diversity (Gastropoda and Bivalvia) are those which may have planktotrophic larval development. Extremely high diversity in such groups as Caenogastropoda or eulamellibranch bivalves is the result of high phylogenetic activity and is associated with the presence of planktotrophic veliger larvae in many members of these groups, although causality has not been shown yet. A new gastropod species and genus, Anachronistella peterwagneri, is described from the Late Triassic Cassian Formation; it is the first known Triassic gastropod with an openly coiled larval shell.", "keyphrases": ["gastropod", "dispersal", "bivalve"]}
{"id": "10.5194/cp-10-955-2014", "title": "Orbitally tuned timescale and astronomical forcing in the middle Eocene to early Oligocene", "abstract": "Abstract. Deciphering the driving mechanisms of Earth system processes, including the climate dynamics expressed as paleoceanographic events, requires a complete, continuous, and high-resolution stratigraphy that is very accurately dated. In this study, a robust astronomically calibrated age model was constructed for the middle Eocene to early Oligocene interval (31\u201343 Ma) in order to permit more detailed study of the exceptional climatic events that occurred during this time, including the middle Eocene climate optimum and the Eocene\u2013Oligocene transition. A goal of this effort is to accurately date the middle Eocene to early Oligocene composite section cored during the Pacific Equatorial Age Transect (PEAT, IODP Exp. 320/321). The stratigraphic framework for the new timescale is based on the identification of the stable long eccentricity cycle in published and new high-resolution records encompassing bulk and benthic stable isotope, calibrated XRF core scanning, and magnetostratigraphic data from ODP Sites 171B-1052, 189-1172, 199-1218, and 207-1260 as well as IODP Sites 320-U1333, and 320-U1334 spanning magnetic polarity Chrons C12n to C20n. Subsequently orbital tuning of the records to the La2011 orbital solution was conducted. The resulting new timescale revises and refines the existing orbitally tuned age model and the geomagnetic polarity timescale from 31 to 43 Ma. The newly defined absolute age for the Eocene\u2013Oligocene boundary validates the astronomical tuned age of 33.89 Ma identified at the Massignano, Italy, global stratotype section and point. The compilation of geochemical records of climate-controlled variability in sedimentation through the middle-to-late Eocene and early Oligocene demonstrates strong power in the eccentricity band that is readily tuned to the latest astronomical solution. Obliquity driven cyclicity is only apparent during 2.4 myr eccentricity cycle minima around 35.5, 38.3, and 40.1 Ma.", "keyphrases": ["tuning", "timescale", "eocene", "oligocene", "eccentricity cycle"]}
{"id": "paleo.011647", "title": "Pre-Gondwanan-breakup origin of Beauprea (Proteaceae) explains its historical presence in New Caledonia and New Zealand", "abstract": "The tropical shrub Beauprea was already present in Gondwana when Zealandia drifted away from Antarctica 82 million years ago. New Caledonia and New Zealand belong to the now largely submerged continent Zealandia. Their high levels of endemism and species richness are usually considered the result of transoceanic dispersal events followed by diversification after they re-emerged from the Pacific Ocean in the mid-Cenozoic. We explore the origin and evolutionary history of Beauprea (Proteaceae), which is now endemic to New Caledonia but was once spread throughout eastern Gondwana, including New Zealand. We review the extensive Beauprea-type pollen data in the fossil records and analyze the relationship of these fossil taxa to extant genera within Proteaceae. We further reconstruct the phylogenetic relations among nine extant species of Beauprea and estimate the age of the Beauprea clade. By incorporating extinct taxa into the Beauprea phylogenetic tree, we reconstruct the ancient distribution of this genus. Our analysis shows that Beauprea originated c. 88 Ma (million years ago) in Antarctica\u2013Southeastern Australia and spread throughout Gondwana before its complete breakup. We propose that Beauprea, already existing as two lineages, was carried with Zealandia when it separated from the rest of Gondwana c. 82 Ma, thus supporting an autochthonous origin for Beauprea species now in New Caledonia and historically in New Zealand up to 1 Ma. We show that the presence of Beauprea through transoceanic dispersal is implausible. This means that neither New Caledonia nor New Zealand has been entirely submerged since the Upper Cretaceous; thus, possible vicariance and allopatry must be taken into account when considering the high levels of endemism and species richness of these island groups.", "keyphrases": ["proteaceae", "new caledonia", "new zealand", "endemism"]}
{"id": "10.1073/pnas.1308997110", "title": "Out of the tropics, but how? Fossils, bridge species, and thermal ranges in the dynamics of the marine latitudinal diversity gradient", "abstract": "Latitudinal diversity gradients are underlain by complex combinations of origination, extinction, and shifts in geographic distribution and therefore are best analyzed by integrating paleontological and neontological data. The fossil record of marine bivalves shows, in three successive late Cenozoic time slices, that most clades (operationally here, genera) tend to originate in the tropics and then expand out of the tropics (OTT) to higher latitudes while retaining their tropical presence. This OTT pattern is robust both to assumptions on the preservation potential of taxa and to taxonomic revisions of extant and fossil species. Range expansion of clades may occur via \u201cbridge species,\u201d which violate climate-niche conservatism to bridge the tropical-temperate boundary in most OTT genera. Substantial time lags (\u223c5 Myr) between the origins of tropical clades and their entry into the temperate zone suggest that OTT events are rare on a per-clade basis. Clades with higher diversification rates within the tropics are the most likely to expand OTT and the most likely to produce multiple bridge species, suggesting that high speciation rates promote the OTT dynamic. Although expansion of thermal tolerances is key to the OTT dynamic, most latitudinally widespread species instead achieve their broad ranges by tracking widespread, spatially-uniform temperatures within the tropics (yielding, via the nonlinear relation between temperature and latitude, a pattern opposite to Rapoport\u2019s rule). This decoupling of range size and temperature tolerance may also explain the differing roles of species and clade ranges in buffering species from background and mass extinctions.", "keyphrases": ["tropic", "bridge specie", "latitudinal diversity gradient", "marine bivalve", "ott"]}
{"id": "10.1080/03115510701305173", "title": "A new Triassic insect fauna from Cerro Bayo, Potrerillos (Mendoza Province, Argentina) with descriptions of new taxa (Insecta: Blattoptera and Coleoptera)", "abstract": "Martins-Neto, R.G., Gallego, O.F. & Zavattieri, A.M., June, 2007. A new Triassic insect fauna from Cerro Bayo, Potrerillos (Mendoza Province, Argentina) with descriptions of new taxa (Insecta: Blattoptera and Coleoptera). Alcheringa 31, 199\u2010213. ISSN 0311-5518. This contribution describes new fossil insect taxa from the early Late Triassic Potrerillos Formation (lower section), at quebrada del puente, Cerro Bayo, Mendoza Province, Argentina. A new family, three new genera, and four new species of Blattoptera are described: Anablatta compacta gen. et sp. nov., Potrerilloblatta stipanicici gen. et sp. nov. (Subioblattidae Schneider), Delpuenteblatta dangeloi gen. et sp. nov. and Lariojablatta neiffi sp. nov. (Delpuenteblattidae fam. nov.); and a new coleopteran species, Delpuentesyne menendezi sp. nov. (Permosynidae Tillyard). These findings extend the stratigraphic distribution of the typical Triassic coleopteran taxa. The new assemblage shares the genus Lariojablatta with the Los Rastros fauna. The Blattoptera and Coleoptera genera differ from those typical of the Australian and South African Triassic biota (Ademosyne for Coleoptera and Triassoblatta and Samaroblatta for Blattoptera) and appear to be endemic to Argentina (Delpuentesyne, Potrerilloblatta and Delpuenteblatta).", "keyphrases": ["triassic insect fauna", "new taxa", "blattoptera"]}
{"id": "10.1126/science.aah4787", "title": "Merging paleobiology with conservation biology to guide the future of terrestrial ecosystems", "abstract": "Looking back to move forward The current impacts of humanity on nature are rapid and destructive, but species turnover and change have occurred throughout the history of life. Although there is much debate about the best approaches to take in conservation, ultimately, we need to permit or enhance the resilience of natural systems so that they can continue to adapt and function into the future. In a Review, Barnosky et al. argue that the best way to do this is to look back at paleontological history as a way to understand how ecological resilience is maintained, even in the face of change. Science, this issue p. eaah4787 BACKGROUND The pace and magnitude of human-caused global change has accelerated dramatically over the past 50 years, overwhelming the capacity of many ecosystems and species to maintain themselves as they have under the more stable conditions that prevailed for at least 11,000 years. The next few decades threaten even more rapid transformations because by 2050, the human population is projected to grow by 3 billion while simultaneously increasing per capita consumption. Thus, to avoid losing many species and the crucial aspects of ecosystems that we need\u2014for both our physical and emotional well-being\u2014new conservation paradigms and integration of information from conservation biology, paleobiology, and the Earth sciences are required. ADVANCES Rather than attempting to hold ecosystems to an idealized conception of the past, as has been the prevailing conservation paradigm until recently, maintaining vibrant ecosystems for the future now requires new approaches that use both historical and novel conservation landscapes, enhance adaptive capacity for ecosystems and organisms, facilitate connectedness, and manage ecosystems for functional integrity rather than focusing entirely on particular species. Scientific breakthroughs needed to underpin such a paradigm shift are emerging at the intersection of ecology and paleobiology, revealing (i) which species and ecosystems will need human intervention to persist; (ii) how to foster population connectivity that anticipates rapidly changing climate and land use; (iii) functional attributes that characterize ecosystems through thousands to millions of years, irrespective of the species that are involved; and (iv) the range of compositional and functional variation that ecosystems have exhibited over their long histories. Such information is necessary for recognizing which current changes foretell transitions to less robust ecological states and which changes may signal benign ecosystem shifts that will cause no substantial loss of ecosystem function or services. Conservation success will also increasingly hinge on choosing among different, sometimes mutually exclusive approaches to best achieve three conceptually distinct goals: maximizing biodiversity, maximizing ecosystem services, and preserving wilderness. These goals vary in applicability depending on whether historical or novel ecosystems are the conservation target. Tradeoffs already occur\u2014for example, managing to maximize certain ecosystem services upon which people depend (such as food production on farm or rangelands) versus maintaining healthy populations of vulnerable species (such as wolves, lions, or elephants). In the future, the choices will be starker, likely involving decisions such as which species are candidates for managed relocation and to which areas, and whether certain areas should be off limits for intensive management, even if it means losing some species that now live there. Developing the capacity to make those choices will require conservation in both historical and novel ecosystems and effective collaboration of scientists, governmental officials, nongovernmental organizations, the legal community, and other stakeholders. OUTLOOK Conservation efforts are currently in a state of transition, with active debate about the relative importance of preserving historical landscapes with minimal human impact on one end of the ideological spectrum versus manipulating novel ecosystems that result from human activities on the other. Although the two approaches are often presented as dichotomous, in fact they are connected by a continuum of practices, and both are needed. In most landscapes, maximizing conservation success will require more integration of paleobiology and conservation biology because in a rapidly changing world, a long-term perspective (encompassing at least millennia) is necessary to specify and select appropriate conservation targets and plans. Although adding this long-term perspective will be essential to sustain biodiversity and all of the facets of nature that humans need as we continue to rapidly change the world over the next few decades, maximizing the chances of success will also require dealing with the root causes of the conservation crisis: rapid growth of the human population, increasing per capita consumption especially in developed countries, and anthropogenic climate change that is rapidly pushing habitats outside the bounds experienced by today\u2019s species. Fewer than 900 mountain gorillas are left in the world, and their continued existence depends upon the choices humans make, exemplifying the state of many species and ecosystems. Can conservation biology save biodiversity and all the aspects of nature that people need and value as 3 billion more of us are added to the planet by 2050, while climate continues to change to states outside the bounds that most of today\u2019s ecosystems have ever experienced? Photo: E. A. Hadly, at Volcanoes National Park, Rwanda Conservation of species and ecosystems is increasingly difficult because anthropogenic impacts are pervasive and accelerating. Under this rapid global change, maximizing conservation success requires a paradigm shift from maintaining ecosystems in idealized past states toward facilitating their adaptive and functional capacities, even as species ebb and flow individually. Developing effective strategies under this new paradigm will require deeper understanding of the long-term dynamics that govern ecosystem persistence and reconciliation of conflicts among approaches to conserving historical versus novel ecosystems. Integrating emerging information from conservation biology, paleobiology, and the Earth sciences is an important step forward on the path to success. Maintaining nature in all its aspects will also entail immediately addressing the overarching threats of growing human population, overconsumption, pollution, and climate change.", "keyphrases": ["paleobiology", "conservation biology", "future", "global change", "million"]}
{"id": "10.1073/pnas.0234701100", "title": "Correlated terrestrial and marine evidence for global climate changes before mass extinction at the Cretaceous\u2013Paleogene boundary", "abstract": "Terrestrial climates near the time of the end-Cretaceous mass extinction are poorly known, limiting understanding of environmentally driven changes in biodiversity that occurred before bolide impact. We estimate paleotemperatures for the last \u22481.1 million years of the Cretaceous (\u224866.6\u201365.5 million years ago, Ma) by using fossil plants from North Dakota and employ paleomagnetic stratigraphy to correlate the results to foraminiferal paleoclimatic data from four middle- and high-latitude sites. Both plants and foraminifera indicate warming near 66.0 Ma, a warming peak from \u224865.8 to 65.6 Ma, and cooling near 65.6 Ma, suggesting that these were global climate shifts. The warming peak coincides with the immigration of a thermophilic flora, maximum plant diversity, and the poleward range expansion of thermophilic foraminifera. Plant data indicate the continuation of relatively cool temperatures across the Cretaceous\u2013Paleogene boundary; there is no indication of a major warming immediately after the boundary as previously reported. Our temperature proxies correspond well with recent pCO2 data from paleosol carbonate, suggesting a coupling of pCO2 and temperature. To the extent that biodiversity is correlated with temperature, estimates of the severity of end-Cretaceous extinctions that are based on occurrence data from the warming peak are probably inflated, as we illustrate for North Dakota plants. However, our analysis of climate and facies considerations shows that the effects of bolide impact should be regarded as the most significant contributor to these plant extinctions.", "keyphrases": ["global climate change", "mass extinction", "cretaceous\u2013paleogene boundary"]}
{"id": "paleo.006337", "title": "Phylogeny of Basal Iguanodonts (Dinosauria: Ornithischia): An Update", "abstract": "The precise phylogenetic relationships of many non-hadrosaurid members of Iguanodontia, i.e., basal iguanodonts, have been unclear. Therefore, to investigate the global phylogeny of basal iguanodonts a comprehensive data matrix was assembled, including nearly every valid taxon of basal iguanodont. The matrix was analyzed in the program TNT, and the maximum agreement subtree of the resulting most parsimonious trees was then calculated in PAUP. Ordering certain multistate characters and omitting taxa through safe taxonomic reduction did not markedly improve resolution. The results provide some new information on the phylogeny of basal iguanodonts, pertaining especially to obscure or recently described taxa, and support some recent taxonomic revisions, such as the splitting of traditional \u201cCamptosaurus\u201d and \u201cIguanodon\u201d. The maximum agreement subtree also shows a close relationship between the Asian Probactrosaurus gobiensis and the North American Eolambia, supporting the previous hypothesis of faunal interchange between Asia and North America in the early Late Cretaceous. Nevertheless, the phylogenetic relationships of many basal iguanodonts remain ambiguous due to the high number of taxa removed from the maximum agreement subtree and poor resolution of consensus trees.", "keyphrases": ["iguanodontia", "phylogeny", "early cretaceous"]}
{"id": "paleo.008416", "title": "Data from: On the probabilities of branch durations and stratigraphic gaps in phylogenies of fossil taxa when rates of diversification vary over time", "abstract": "The time separating the first appearances of species from their divergences from related taxa affects assessments of macroevolutionary hypotheses about rates of anatomical or ecological change. Branch durations necessarily posit stratigraphic gaps in sampling within a clade over which we have failed to sample predecessors (ancestors) and over which there are no divergences leading to sampled relatives (sister taxa). The former reflects only sampling rates, whereas the latter reflects sampling, origination, and extinction rates. Because all three rates vary over time, the probability of a branch duration of any particular length will differ depending on when in the Phanerozoic that branch duration spans. Here, I present a birth-death-sampling model allowing interval-to-interval variation in diversification and sampling rates. Increasing either origination or sampling rates increases the probability of finding sister taxa that diverge both during and before intervals of high sampling/origination. Conversely, elevated extinction reduces the probability of divergences from sampled sister taxa before and during intervals of elevated extinction. In the case of total extinction, a Signor-Lipps will reduce expected sister taxa leading up to the extinction, with the possible effect stretching back many millions of years when sampling is low. Simulations indicate that this approach provides reasonable estimates of branch duration probabilities under a variety of circumstances. Because current probability models for describing morphological evolution are less advanced than methods for inferring diversification and sampling rates, branch duration priors allowing for timevarying diversification could be a potent tool for phylogenetic inference with fossil data.", "keyphrases": ["branch duration", "stratigraphic gap", "phylogeny"]}
{"id": "paleo.011081", "title": "Asteroid impact, not volcanism, caused the end-Cretaceous dinosaur extinction", "abstract": "Significance We present a quantitative test of end-Cretaceous extinction scenarios and how these would have affected dinosaur habitats. Combining climate and ecological modeling tools, we demonstrate a substantial detrimental effect on dinosaur habitats caused by an impact winter scenario triggered by the Chicxulub asteroid. We were not able to obtain such an extinction state with several modeling scenarios of Deccan volcanism. We further show that the concomitant prolonged eruption of the Deccan traps might have acted as an ameliorating agent, buffering the negative effects on climate and global ecosystems that the asteroid impact produced at the Cretaceous\u2013Paleogene boundary. The Cretaceous/Paleogene mass extinction, 66 Ma, included the demise of non-avian dinosaurs. Intense debate has focused on the relative roles of Deccan volcanism and the Chicxulub asteroid impact as kill mechanisms for this event. Here, we combine fossil-occurrence data with paleoclimate and habitat suitability models to evaluate dinosaur habitability in the wake of various asteroid impact and Deccan volcanism scenarios. Asteroid impact models generate a prolonged cold winter that suppresses potential global dinosaur habitats. Conversely, long-term forcing from Deccan volcanism (carbon dioxide [CO2]-induced warming) leads to increased habitat suitability. Short-term (aerosol cooling) volcanism still allows equatorial habitability. These results support the asteroid impact as the main driver of the non-avian dinosaur extinction. By contrast, induced warming from volcanism mitigated the most extreme effects of asteroid impact, potentially reducing the extinction severity.", "keyphrases": ["volcanism", "dinosaur extinction", "asteroid impact"]}
{"id": "paleo.011569", "title": "Non\u2010enzymatic glycolysis and pentose phosphate pathway\u2010like reactions in a plausible Archean ocean", "abstract": "The reaction sequences of central metabolism, glycolysis and the pentose phosphate pathway provide essential precursors for nucleic acids, amino acids and lipids. However, their evolutionary origins are not yet understood. Here, we provide evidence that their structure could have been fundamentally shaped by the general chemical environments in earth's earliest oceans. We reconstructed potential scenarios for oceans of the prebiotic Archean based on the composition of early sediments. We report that the resultant reaction milieu catalyses the interconversion of metabolites that in modern organisms constitute glycolysis and the pentose phosphate pathway. The 29 observed reactions include the formation and/or interconversion of glucose, pyruvate, the nucleic acid precursor ribose\u20105\u2010phosphate and the amino acid precursor erythrose\u20104\u2010phosphate, antedating reactions sequences similar to that used by the metabolic pathways. Moreover, the Archean ocean mimetic increased the stability of the phosphorylated intermediates and accelerated the rate of intermediate reactions and pyruvate production. The catalytic capacity of the reconstructed ocean milieu was attributable to its metal content. The reactions were particularly sensitive to ferrous iron Fe(II), which is understood to have had high concentrations in the Archean oceans. These observations reveal that reaction sequences that constitute central carbon metabolism could have been constrained by the iron\u2010rich oceanic environment of the early Archean. The origin of metabolism could thus date back to the prebiotic world.", "keyphrases": ["glycolysis", "reaction", "archean ocean", "pentose phosphate pathway"]}
{"id": "10.1017/pab.2017.39", "title": "Breaking down the lithification bias: the effect of preferential sampling of larger specimens on the estimate of species richness, evenness, and average specimen size", "abstract": "Abstract. \n Lithification, the transition of unconsolidated sediments to fully indurated rocks, can potentially bias estimates of species richness, evenness, and body size distribution derived from fossil assemblages. Fossil collections made from well-indurated rocks consistently exhibit lower species richness, lower evenness, and larger average specimen size relative to collections made from unconsolidated sediments, even when collections are drawn from the same assemblage. This phenomenon is known as \u201clithification bias.\u201d While the bias itself has been demonstrated empirically, much less attention has been paid to its causes. Proposed causes include taphonomic processes (e.g., destruction of small specimens during early diagenesis) and methodological differences (e.g., sieving vs. counting specimens on outcrops, bedding surfaces, or mechanically split surfaces). Here we investigate the potential effects of preferential intersection that could also result in a methodologically related bias: the preferential sampling of larger specimens relative to smaller ones when fossils are counted on rock surfaces. We used an analogue model to simulate preferential intersection (fossil collection via splitting fossiliferous rocks) and compare the results with a random-draw model that approximates the effects of sieving. The model was parameterized using nine different combinations of species abundance and species size distributions. The results show that, with rare exceptions, species richness is 5\u201323% lower, evenness 5\u201325% lower, and average specimen size 24\u2013150% larger in preferential-intersection than in random-draw simulations. We conclude that preferential intersection can impose a significant bias independent of other mechanisms (e.g., preferential destruction of smaller specimens during diagenetic or sampling processes), that the magnitude of this bias is partially dependent on the species abundance and size distributions, and that this bias alone does not fully account for empirically observed lithification bias on species richness (i.e., other sources of bias are also at work).", "keyphrases": ["lithification bias", "preferential sampling", "average speciman size"]}
{"id": "10.1002/ajpa.1330680102", "title": "Multifactorial determination of skeletal age at death: a method and blind tests of its accuracy.", "abstract": "Traditional methods of estimating skeletal age at death have relied solely on the pubic symphyseal face or on this indicator combined with others in nonsystematic ways. A multifactorial method is presented that uses a principal components weighting of five indicators (public symphyseal face, auricular surface, radiographs of proximal femur, dental wear, and suture closure). This method has been tested by completely blind assessment of age in two samples from the Todd collection carefully screened for accuracy of stated age at death. Results show a marked superiority of the multifactorial method over any single indicator with respect to both bias and accuracy. This represents the first truly blind test of an age-at-death indicator or system, as the test populations were independent of the system(s) being tested, and the age, sex, and ethnogeographic origin of the individuals being assessed (as well as the compositions of the test samples with respect to these variables) were completely unknown until the tests were completed. Implications for paleodemography are discussed.", "keyphrases": ["skeletal age", "death", "accuracy"]}
{"id": "paleo.012691", "title": "mapDamage2.0: fast approximate Bayesian estimates of ancient DNA damage parameters", "abstract": "Motivation: Ancient DNA (aDNA) molecules in fossilized bones and teeth, coprolites, sediments, mummified specimens and museum collections represent fantastic sources of information for evolutionary biologists, revealing the agents of past epidemics and the dynamics of past populations. However, the analysis of aDNA generally faces two major issues. Firstly, sequences consist of a mixture of endogenous and various exogenous backgrounds, mostly microbial. Secondly, high nucleotide misincorporation rates can be observed as a result of severe post-mortem DNA damage. Such misincorporation patterns are instrumental to authenticate ancient sequences versus modern contaminants. We recently developed the user-friendly mapDamage package that identifies such patterns from next-generation sequencing (NGS) sequence datasets. The absence of formal statistical modeling of the DNA damage process, however, precluded rigorous quantitative comparisons across samples. Results: Here, we describe mapDamage 2.0 that extends the original features of mapDamage by incorporating a statistical model of DNA damage. Assuming that damage events depend only on sequencing position and post-mortem deamination, our Bayesian statistical framework provides estimates of four key features of aDNA molecules: the average length of overhangs (\u03bb), nick frequency (\u03bd) and cytosine deamination rates in both double-stranded regions () and overhangs (). Our model enables rescaling base quality scores according to their probability of being damaged. mapDamage 2.0 handles NGS datasets with ease and is compatible with a wide range of DNA library protocols. Availability: mapDamage 2.0 is available at ginolhac.github.io/mapDamage/ as a Python package and documentation is maintained at the Centre for GeoGenetics Web site (geogenetics.ku.dk/publications/mapdamage2.0/). Contact: jonsson.hakon@gmail.com Supplementary information: Supplementary data are available at Bioinformatics online.", "keyphrases": ["ancient dna", "adna", "mapdamage", "deamination", "dna damage pattern"]}
{"id": "paleo.007759", "title": "A new species of Cricosaurus (Thalattosuchia, Metriorhynchidae) based upon a remarkably well-preserved skeleton from the Upper Jurassic of Germany", "abstract": "Herein we describe a new and exceptionally well-preserved skeleton of the metriorhynchid thalattosuchian Cricosaurus from the upper Kimmeridgian Torleite Formation of Painten in Bavaria (Southern Germany). The specimen is articulated, shows soft-tissue preservation, and represents one of the most complete metriorhynchid skeletons known. The exceptional preservation allows us to explore the morphological variation of the tail region in the Metriorhynchidae, a part of the skeleton that has long been neglected. Based on our description and phylogenetic analyses, we name this specimen Cricosaurus albersdoerferi sp. nov. Our phylogenetic analyses recover a Cricosaurus subclade composed of four species from Southern Germany and one from Argentina. We provide revised diagnoses for the Southern German members of this subclade, revealing the presence of at least four closely-related Cricosaurus species in the upper Kimmeridgian-early Tithonian of Southern Germany. Interestingly, within this subclade there is evidence of rapid change in tail construction and feeding ecology. However, there is no evidence of sympatry between these taxa, and the two species known from the same ammonite subzone are exclusively found in different northernTethys lagoons. Most interesting, however, is the variation in the skulls, dorsal neural spines, the tail displacement units, and flukes between these different species. This previously unexplored variation within Metriorhynchidae hints to differences in locomotory abilities between different species. Sven Sachs. Naturkunde-Museum Bielefeld, Abteilung Geowissenschaften, Adenauerplatz 2, 33602 Bielefeld, Germany, and Im Hof 9, 51766 Engelskirchen, Germany. Sachs.Pal@gmail.com Mark T. Young. School of GeoSciences, Grant Institute, University of Edinburgh, James Hutton Road, Edinburgh, EH9 3FE, UK. Mark.Young@ed.ac.uk Pascal Abel. Senckenberg Centre for Human Evolution and Palaeoenvironment, Eberhard-KarlsUniversit\u00e4t T\u00fcbingen, Sigwartstra\u00dfe 10, 72076 T\u00fcbingen, Germany pascal.abel@ifg.uni-tuebingen.de], Heinrich Mallison. Palaeo3D, Dorfstr. 11, 86641 Rain am Lech, Germany and CeNak, Universit\u00e4t SACHS ET AL.: A NEW Cricosaurus SPECIES 2 Hamburg, Martin-Luther-King-Platz 3, 20146 Hamburg, Germany. mallison@palaeo3d.com", "keyphrases": ["metriorhynchidae", "well-preserved skeleton", "germany", "skull"]}
{"id": "paleo.006313", "title": "Improvements in the fossil record may largely resolve current conflicts between morphological and molecular estimates of mammal phylogeny", "abstract": "Phylogenies of mammals based on morphological data continue to show several major areas of conflict with the current consensus view of their relationships, which is based largely on molecular data. This raises doubts as to whether current morphological character sets are able to accurately resolve mammal relationships. We tested this under a hypothetical \u2018best case scenario\u2019 by using ancestral state reconstruction (under both maximum parsimony and maximum likelihood) to infer the morphologies of fossil ancestors for all clades present in a recent comprehensive DNA sequence-based phylogeny of mammals, and then seeing what effect the subsequent inclusion of these predicted ancestors had on unconstrained phylogenetic analyses of morphological data. We found that this resulted in topologies that are highly congruent with the current consensus phylogeny, at least when the predicted ancestors are assumed to be well preserved and densely sampled. Most strikingly, several analyses recovered the monophyly of clades that have never been found in previous morphology-only studies, such as Afrotheria and Laurasiatheria. Our results suggest that, at least in principle, improvements in the fossil record\u2014specifically the discovery of fossil taxa that preserve the ancestral or near-ancestral morphologies of the nodes in the current consensus\u2014may be sufficient to largely reconcile morphological and molecular estimates of mammal phylogeny, even using current morphological character sets.", "keyphrases": ["conflict", "phylogeny", "dna", "laurasiatheria", "improvement"]}
{"id": "10.1111/j.1095-8312.2007.00881.x", "title": "Relationships between bone growth rate, body mass and resting metabolic rate in growing amniotes: a phylogenetic approach", "abstract": "We explored the factors that explain the variation in resting metabolic rates (RMR) in growing amniotes by using the phylogenetic comparative method. For this, we measured raw RMR (mL\u00a0O2\u00a0h\u22121), body mass, body mass growth rate, and periosteal bone growth rate in a sample of 44 growing individuals belonging to 13 species of amniotes. We performed variation partitioning analyses, which showed that phylogeny explains a significant fraction of the variation of mass-specific RMR (mL\u00a0O2\u00a0h\u22121\u00a0g\u22121), and that the cost of growth is much higher than the cost of maintenance. Moreover, we tested the hypothesis of the independence of energy allocation, and found that maintenance metabolism and growth rates are not significantly related. Finally, we calculated the statistical parameters of the relationship between geometry-corrected RMR (mL O2\u00a0h\u22121\u00a0g\u22120.67) and bone growth rate. This relationship could potentially be used in palaeobiology to infer RMR from bone tissue samples of fossil species by assuming Amprino\u2019s rule (according to which bone tissue types reflect bone growth rates). These estimates would be especially interesting for Mesozoic non-avian theropod dinosaurs and Permian and Triassic therapsids to investigate, respectively, the origin of avian and mammalian endothermy.\u00a0\u00a9 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92, 63\u201376.", "keyphrases": ["bone growth rate", "metabolic rate", "amniote"]}
{"id": "10.1111/joa.12874", "title": "The importance of muscle architecture in biomechanical reconstructions of extinct animals: a\u00a0case study using Tyrannosaurus rex", "abstract": "Functional reconstructions of extinct animals represent a crucial step towards understanding palaeocological interactions, selective pressures and macroevolutionary patterns in the fossil record. In recent years, computational approaches have revolutionised the field of \u2018evolutionary biomechanics\u2019 and have, in general, resulted in convergence of quantitative estimates of performance on increasingly narrow ranges for well studied taxa. Studies of body mass and locomotor performance of Tyrannosaurus rex \u2013 arguably the most intensively studied extinct animal \u2013 typify this pattern, with numerous independent studies predicting similar body masses and maximum locomotor speeds for this animal. In stark contrast to this trend, recent estimates of maximum bite force in T. rex vary considerably (> 50%) despite use of similar quantitative methodologies. Herein we demonstrate that the mechanistic causes of these disparate predictions are indicative of important and underappreciated limiting factors in biomechanical reconstructions of extinct organisms. Detailed comparison of previous models of T. rex bite force reveals that estimations of muscle fibre lengths and architecture are the principal source of disagreement between studies, and therefore that these parameters represents the greatest source of uncertainty in these reconstructions, and potentially therefore extinct animals generally. To address the issue of fibre length and architecture estimation in extinct animals we present data tabulated from the literature of muscle architecture from over 1100 muscles measured in extant terrestrial animals. Application of this dataset in a reanalysis of T. rex bite force emphasises the need for more data on jaw musculature from living carnivorous animals, alongside increased sophistication of modelling approaches. In the latter respect we predict that implementing limits on skeletal loading into musculoskeletal models will narrow predictions for T. rex bite force by excluding higher\u2010end estimates.", "keyphrases": ["muscle architecture", "biomechanical reconstruction", "extinct animal"]}
{"id": "paleo.012680", "title": "Ancient Egyptian mummy genomes suggest an increase of Sub-Saharan African ancestry in post-Roman periods", "abstract": "Egypt, located on the isthmus of Africa, is an ideal region to study historical population dynamics due to its geographic location and documented interactions with ancient civilizations in Africa, Asia and Europe. Particularly, in the first millennium BCE Egypt endured foreign domination leading to growing numbers of foreigners living within its borders possibly contributing genetically to the local population. Here we present 90 mitochondrial genomes as well as genome-wide data sets from three individuals obtained from Egyptian mummies. The samples recovered from Middle Egypt span around 1,300 years of ancient Egyptian history from the New Kingdom to the Roman Period. Our analyses reveal that ancient Egyptians shared more ancestry with Near Easterners than present-day Egyptians, who received additional sub-Saharan admixture in more recent times. This analysis establishes ancient Egyptian mummies as a genetic source to study ancient human history and offers the perspective of deciphering Egypt's past at a genome-wide level.", "keyphrases": ["genome", "ancestry", "new kingdom", "roman period"]}
{"id": "paleo.008183", "title": "Thresholds of temperature change for mass extinctions", "abstract": "Climate change is a critical factor affecting biodiversity. However, the quantitative relationship between temperature change and extinction is unclear. Here, we analyze magnitudes and rates of temperature change and extinction rates of marine fossils through the past 450 million years (Myr). The results show that both the rate and magnitude of temperature change are significantly positively correlated with the extinction rate of marine animals. Major mass extinctions in the Phanerozoic can be linked to thresholds in climate change (warming or cooling) that equate to magnitudes >5.2 \u00b0C and rates >10 \u00b0C/Myr. The significant relationship between temperature change and extinction still exists when we exclude the five largest mass extinctions of the Phanerozoic. Our findings predict that a temperature increase of 5.2 \u00b0C above the pre-industrial level at present rates of increase would likely result in mass extinction comparable to that of the major Phanerozoic events, even without other, non-climatic anthropogenic impacts.", "keyphrases": ["temperature change", "mass extinction", "threshold"]}
{"id": "10.1093/nsr/nwu055", "title": "The Jehol Biota, an Early Cretaceous terrestrial Lagerst\u00e4tte: new discoveries and implications", "abstract": "The study of the Early Cretaceous terrestrial Jehol Biota, which provides a rare window for reconstruction of a Lower Cretaceous terrestrial ecosystem, is reviewed with a focus on some of the latest progress. A newly proposed definition of the biota based on paleoecology and taphonomy is accepted. Although the Jehol fossils are mainly preserved in two types of sedimentary rocks, there are various types of preservation with a complex mechanism that remains to be understood. New discoveries of significant taxa from the Jehol Biota, with an updated introduction of its diversity, confirm that the Jehol Biota represents one of the most diversified biotas of the Mesozoic. The evolutionary significance of major biological groups (e.g. dinosaurs, birds, mammals, pterosaurs, insects, and plants) is discussed mainly in the light of recent discoveries, and some of the most remarkable aspects of the biota are highlighted. The global and local geological, paleogeographic, and paleoenvironmental background of the Jehol Biota have contributed to the unique composition, evolution, and preservation of the biota, demonstrating widespread faunal exchanges between Asia and other continents caused by the presence of the Eurasia-North American continental mass and its link to South America, and confirming northeastern China as the origin and diversification center for a variety of Cretaceous biological groups. Although some progress has been made on the reconstruction of the paleotemperature at the time of the Jehol Biota, much more work is needed to confirm a possible link between the remarkable diversity of the biota and the cold intervals during the Early Cretaceous. Finally, future directions for the study of the Jehol Biota are proposed that highlight the great potential of more comprehensive and multidisciplinary studies to further our understanding of the biological and geological implications of the Jehol Lagerstatte.", "keyphrases": ["jehol biota", "new discovery", "cretaceous terrestrial ecosystem", "taphonomy", "vertebrate"]}
{"id": "paleo.012890", "title": "Mind the Outgroup and Bare Branches in Total-Evidence Dating: a Case Study of Pimpliform Darwin Wasps (Hymenoptera, Ichneumonidae)", "abstract": "Abstract Taxon sampling is a central aspect of phylogenetic study design, but it has received limited attention in the context of total-evidence dating, a widely used dating approach that directly integrates molecular and morphological information from extant and fossil taxa. We here assess the impact of commonly employed outgroup sampling schemes and missing morphological data in extant taxa on age estimates in a total-evidence dating analysis under the uniform tree prior. Our study group is Pimpliformes, a highly diverse, rapidly radiating group of parasitoid wasps of the family Ichneumonidae. We analyze a data set comprising 201 extant and 79 fossil taxa, including the oldest fossils of the family from the Early Cretaceous and the first unequivocal representatives of extant subfamilies from the mid-Paleogene. Based on newly compiled molecular data from ten nuclear genes and a morphological matrix that includes 222 characters, we show that age estimates become both older and less precise with the inclusion of more distant and more poorly sampled outgroups. These outgroups not only lack morphological and temporal information but also sit on long terminal branches and considerably increase the evolutionary rate heterogeneity. In addition, we discover an artifact that might be detrimental for total-evidence dating: \u201cbare-branch attraction,\u201d namely high attachment probabilities of certain fossils to terminal branches for which morphological data are missing. Using computer simulations, we confirm the generality of this phenomenon and show that a large phylogenetic distance to any of the extant taxa, rather than just older age, increases the risk of a fossil being misplaced due to bare-branch attraction. After restricting outgroup sampling and adding morphological data for the previously attracting, bare branches, we recover a Jurassic origin for Pimpliformes and Ichneumonidae. This first age estimate for the group not only suggests an older origin than previously thought but also that diversification of the crown group happened well before the Cretaceous-Paleogene boundary. Our case study demonstrates that in order to obtain robust age estimates, total-evidence dating studies need to be based on a thorough and balanced sampling of both extant and fossil taxa, with the aim of minimizing evolutionary rate heterogeneity and missing morphological information. [Bare-branch attraction; ichneumonids; fossils; morphological matrix; phylogeny; RoguePlots.]", "keyphrases": ["outgroup", "total-evidence", "ichneumonidae", "early cretaceous"]}
{"id": "paleo.010927", "title": "Mitochondrial Phylogenomics of Modern and Ancient Equids", "abstract": "The genus Equus is richly represented in the fossil record, yet our understanding of taxonomic relationships within this genus remains limited. To estimate the phylogenetic relationships among modern horses, zebras, asses and donkeys, we generated the first data set including complete mitochondrial sequences from all seven extant lineages within the genus Equus. Bayesian and Maximum Likelihood phylogenetic inference confirms that zebras are monophyletic within the genus, and the Plains and Grevy\u2019s zebras form a well-supported monophyletic group. Using ancient DNA techniques, we further characterize the complete mitochondrial genomes of three extinct equid lineages (the New World stilt-legged horses, NWSLH; the subgenus Sussemionus; and the Quagga, Equus quagga quagga). Comparisons with extant taxa confirm the NWSLH as being part of the caballines, and the Quagga and Plains zebras as being conspecific. However, the evolutionary relationships among the non-caballine lineages, including the now-extinct subgenus Sussemionus, remain unresolved, most likely due to extremely rapid radiation within this group. The closest living outgroups (rhinos and tapirs) were found to be too phylogenetically distant to calibrate reliable molecular clocks. Additional mitochondrial genome sequence data, including radiocarbon dated ancient equids, will be required before revisiting the exact timing of the lineage radiation leading up to modern equids, which for now were found to have possibly shared a common ancestor as far as up to 4 Million years ago (Mya).", "keyphrases": ["ancient equid", "horse", "dna"]}
{"id": "paleo.002063", "title": "Amniotes through major biological crises: faunal turnover among Parareptiles and the end\u2010Permian mass extinction", "abstract": "Abstract:\u2002 The Parareptilia are a small but ecologically and morphologically diverse clade of Permian and Triassic crown amniotes generally considered to be phylogenetically more proximal to eureptiles (diapsids and their kin) than to synapsids (mammals and their kin). A recent supertree provides impetus for an analysis of parareptile diversity through time and for examining the influence of the end\u2010Permian mass extinction on the clade\u2019s origination and extinction rates. Phylogeny\u2010corrected measures of diversity have a significant impact on both rates and the distribution of origination and extinction intensities. Time calibration generally results in a closer correspondence between origination and extinction rate values than in the case of no time correction. Near the end\u2010Permian event, extinction levels are not significantly higher than origination levels, particularly when time calibration is introduced. Finally, regardless of time calibration and/or phylogenetic correction, the distribution of rates does not differ significantly from unimodal. The curves of rate values are discussed in the light of the numbers and distributions of both range extensions and ghost lineages. The disjoint time distributions of major parareptile clades (e.g. procolophonoids and nycteroleterids\u2010pareiasaurs) are mostly responsible for the occurrence of long\u2010range extensions throughout the Permian. Available data are not consistent with a model of sudden decline at the end\u2010Permian but rather suggest a rapid alternation of originations and extinctions in a number of parareptile groups, both before and after the Permian/Triassic boundary.", "keyphrases": ["parareptile", "mass extinction", "origination", "correction"]}
{"id": "paleo.000618", "title": "Semicircular canals in Anolis lizards: ecomorphological convergence and ecomorph affinities of fossil species", "abstract": "Anolis lizards are a model system for the study of adaptive radiation and convergent evolution. Greater Antillean anoles have repeatedly evolved six similar forms or ecomorphs: crown-giant, grass-bush, twig, trunk, trunk-crown and trunkground. Members of each ecomorph category possess a specific set of morphological, ecological and behavioural characteristics which have been acquired convergently. Here we test whether the semicircular canal system-the organ of balance during movement-is also convergent among ecomorphs, reflecting the shared sensory requirements of their ecological niches. As semicircular canal shape has been shown to reflect different locomotor strategies, we hypothesized that each Anolis ecomorph would have a unique canal morphology. Using three-dimensional semilandmarks and geometric morphometrics, semicircular canal shape was characterized in 41 Anolis species from the Greater Antilles and the relationship between canal shape and ecomorph grouping, phylogenetic history, size, head dimensions, and perch characteristics was assessed. Further, canal morphology of modern species was used to predict the ecomorph affinity of five fossil anoles from the Miocene of the Dominican Republic. Of the covariates tested, our study recovered ecomorph as the single-most important covariate of canal morphology in modern taxa; although phylogenetic history, size, and head dimensions also showed a small, yet significant correlation with shape. Surprisingly, perch characteristics were not found to be significant covariates of canal shape, even though they are important habitat variables. Using", "keyphrases": ["anolis lizard", "ecomorph affinity", "canal shape", "modern specie", "semicircular canal"]}
{"id": "10.18814/epiiugs/2013/v36i4/001", "title": "Devonian deposits of the Baruunhuurai Terrane, Western Mongolia (IGCP 596 Field Workshop)", "abstract": "IGCP 596 (2011-2015) has a primary focus on climate change and biodiversity patterns in the Mid-Paleozoic (Early Devonian to Late Carboniferous). As a part of this project, we conducted a field workshop in western Mongolia in the summer of 2012. The goal was to locate fossiliferous sections that expose the stage boundaries from the Eifelian/Givetian boundary (Middle Devonian) to the Devonian/Carboniferous boundary to expand our knowledge of the key Devonian biotic and geochemical events such as the Frasnian/Famennian extinction event and the Kacak, Kellwasser and Hangenberg oceanographic events. During the field workshop, we examined sections in the Nariinhar Formation, Baruunhuurai Formation and Samnuuruul Formation from the Baruunhuurai Terrane.", "keyphrases": ["baruunhuurai terrane", "western mongolia", "field workshop", "volcaniclastic rock", "carbonate facie"]}
{"id": "paleo.007166", "title": "Testing the molecular clock using mechanistic models of fossil preservation and molecular evolution", "abstract": "Molecular sequence data provide information about relative times only, and fossil-based age constraints are the ultimate source of information about absolute times in molecular clock dating analyses. Thus, fossil calibrations are critical to molecular clock dating, but competing methods are difficult to evaluate empirically because the true evolutionary time scale is never known. Here, we combine mechanistic models of fossil preservation and sequence evolution in simulations to evaluate different approaches to constructing fossil calibrations and their impact on Bayesian molecular clock dating, and the relative impact of fossil versus molecular sampling. We show that divergence time estimation is impacted by the model of fossil preservation, sampling intensity and tree shape. The addition of sequence data may improve molecular clock estimates, but accuracy and precision is dominated by the quality of the fossil calibrations. Posterior means and medians are poor representatives of true divergence times; posterior intervals provide a much more accurate estimate of divergence times, though they may be wide and often do not have high coverage probability. Our results highlight the importance of increased fossil sampling and improved statistical approaches to generating calibrations, which should incorporate the non-uniform nature of ecological and temporal fossil species distributions.", "keyphrases": ["molecular clock", "mechanistic model", "fossil preservation"]}
{"id": "10.7717/peerj.2639", "title": "Hyainailourine and teratodontine cranial material from the late Eocene of Egypt and the application of parsimony and Bayesian methods to the phylogeny and biogeography of Hyaenodonta (Placentalia, Mammalia)", "abstract": "Hyaenodonta is a diverse, extinct group of carnivorous mammals that included weasel- to rhinoceros-sized species. The oldest-known hyaenodont fossils are from the middle Paleocene of North Africa and the antiquity of the group in Afro-Arabia led to the hypothesis that it originated there and dispersed to Asia, Europe, and North America. Here we describe two new hyaenodont species based on the oldest hyaenodont cranial specimens known from Afro-Arabia. The material was collected from the latest Eocene Locality 41 (L-41, \u223c34 Ma) in the Fayum Depression, Egypt. Akhnatenavus nefertiticyon sp. nov. has specialized, hypercarnivorous molars and an elongate cranial vault. In A. nefertiticyon the tallest, piercing cusp on M1\u2013M2 is the paracone. Brychotherium ephalmos gen. et sp. nov. has more generalized molars that retain the metacone and complex talonids. In B. ephalmos the tallest, piercing cusp on M1\u2013M2 is the metacone. We incorporate this new material into a series of phylogenetic analyses using a character-taxon matrix that includes novel dental, cranial, and postcranial characters, and samples extensively from the global record of the group. The phylogenetic analysis includes the first application of Bayesian methods to hyaenodont relationships. B. ephalmos is consistently placed within Teratodontinae, an Afro-Arabian clade with several generalist and hypercarnivorous forms, and Akhnatenavus is consistently recovered in Hyainailourinae as part of an Afro-Arabian radiation. The phylogenetic results suggest that hypercarnivory evolved independently three times within Hyaenodonta: in Teratodontinae, in Hyainailourinae, and in Hyaenodontinae. Teratodontines are consistently placed in a close relationship with Hyainailouridae (Hyainailourinae + Apterodontinae) to the exclusion of \u201cproviverrines,\u201d hyaenodontines, and several North American clades, and we propose that the superfamily Hyainailouroidea be used to describe this relationship. Using the topologies recovered from each phylogenetic method, we reconstructed the biogeographic history of Hyaenodonta using parsimony optimization (PO), likelihood optimization (LO), and Bayesian Binary Markov chain Monte Carlo (MCMC) to examine support for the Afro-Arabian origin of Hyaenodonta. Across all analyses, we found that Hyaenodonta most likely originated in Europe, rather than Afro-Arabia. The clade is estimated by tip-dating analysis to have undergone a rapid radiation in the Late Cretaceous and Paleocene; a radiation currently not documented by fossil evidence. During the Paleocene, lineages are reconstructed as dispersing to Asia, Afro-Arabia, and North America. The place of origin of Hyainailouroidea is likely Afro-Arabia according to the Bayesian topologies but it is ambiguous using parsimony. All topologies support the constituent clades\u2013Hyainailourinae, Apterodontinae, and Teratodontinae\u2013as Afro-Arabian and tip-dating estimates that each clade is established in Afro-Arabia by the middle Eocene.", "keyphrases": ["parsimony", "hyaenodonta", "character-taxon matrix", "hyainailouroidea"]}
{"id": "10.1002/jqs.2634", "title": "Influence of tidal\u2010range change and sediment compaction on Holocene relative sea\u2010level change in New Jersey, USA", "abstract": "We investigated the effect of tidal\u2010range change and sediment compaction on reconstructions of Holocene relative sea level (RSL) in New Jersey, USA. We updated a published sea\u2010level database to generate 50 sea\u2010level index points and ten limiting dates that define continuously rising RSL in New Jersey during the Holocene. There is scatter among the index points, particularly those older than 7 ka. A numerical model estimated that paleotidal range was relatively constant during the mid and late Holocene, but rapidly increased between 9 and 8 ka, leading to an underestimation of RSL by \u223c0.5\u2009m. We adjusted the sea\u2010level index points using the paleotidal model prior to assessing the influence of compaction on organic samples with clastic deposits above and below (an intercalated sea\u2010level index point). We found a significant relationship (p\u2009=\u20090.01) with the thickness of the overburden (r\u2009=\u20090.85). We altered the altitude of intercalated index points using this simple stratigraphic relationship, which reduced vertical scatter in sea\u2010level reconstructions. We conclude that RSL rose at an average rate of 4\u2009mm a\u22121 from 10 ka to 6 ka, 2\u2009mm a\u22121 from 6 ka to 2 ka, and 1.3\u2009mm a\u22121 from 2 ka to AD 1900. Copyright \u00a9 2013 John Wiley & Sons, Ltd.", "keyphrases": ["tidal\u2010range change", "sediment compaction", "holocene"]}
{"id": "10.3374/014.056.0203", "title": "A Review of the Fossil Record of Turtles of the Clade Baenidae", "abstract": "Abstract The fossil record of the turtle clade Baenidae ranges from the Early Cretaceous (Aptian\u2014Albian) to the Eocene. The group is present throughout North America during the Early Cretaceous, but is restricted to the western portions of the continents in the Late Cretaceous and Paleogene. No credible remains of the clade have been reported outside of North America to date. Baenids were warmadapted freshwater aquatic turtles that supported high levels of diversity at times through niche partitioning, particularly by adapting to a broad range of dietary preferences ranging from omnivorous to molluscivorous. Current phylogenies place Baenidae near the split of crown-group Testudines. Within Baenidae three more inclusive, named clades are recognized: Baenodda, Palatobaeninae and Eubaeninae. A taxonomic review of the group concludes that of 49 named taxa, 30 are nomina valida, 12 are nomina invalida and 7 are nomina dubia.", "keyphrases": ["review", "baenidae", "early cretaceous", "eocene"]}
{"id": "paleo.007023", "title": "THE MORPHOLOGY OF HYOLITHIDS AND ITS FUNCTIONAL IMPLICATIONS", "abstract": "Abstract:\u2002 The exceptionally preserved hyolithids Gompholites striatulus, Maxilites robustus, Maxilites snajdri and Maxilites sp. are described with particular emphasis on helen and muscle scar morphology. These two aspects of hyolithid morphology have remained controversial. In life position, each helen curved ventrally. When the operculum closed the aperture of the conch, each helen was locked at the commissure slit with its dorsal edge tilted forward. Inside the conch, it was held in the dorsal apertural plane and clear of the inner surface of the operculum. Previously unidentified muscle scars are described from both the operculum and the conch. Dorsal scars on the conch aperture held muscles directed to the operculum. Comparative study of the muscle insertion pattern indicates that hyolithids did not have serially arranged muscles and that all hyolithids may have had a common skeleto\u2010muscular system. The arrangement of the muscle scars with respect to the helens suggests that the latter were capable of relatively complex movements and could have been used to propel the organism over the substrate. The general morphology and orientation of the helens suggests that in addition they functioned to stabilize the organism on the sea\u2010floor.", "keyphrases": ["morphology", "hyolithid", "operculum", "conch", "lateral spine"]}
{"id": "paleo.007227", "title": "Dispersal and diversity in the earliest North American sauropodomorph dinosaurs, with a description of a new taxon", "abstract": "Sauropodomorph dinosaurs originated in the Southern Hemisphere in the Middle or Late Triassic and are commonly portrayed as spreading rapidly to all corners of Pangaea as part of a uniform Late Triassic to Early Jurassic cosmopolitan dinosaur fauna. Under this model, dispersal allegedly inhibited dinosaurian diversification, while vicariance and local extinction enhanced it. However, apomorphy-based analyses of the known fossil record indicate that sauropodomorphs were absent in North America until the Early Jurassic, reframing the temporal context of their arrival. We describe a new taxon from the Kayenta Formation of Arizona that comprises the third diagnosable sauropodomorph from the Early Jurassic of North America. We analysed its relationships to test whether sauropodomorphs reached North America in a single sweepstakes event or in separate dispersals. Our finding of separate arrivals by all three taxa suggests dispersal as a chief factor in dinosaurian diversification during at least the early Mesozoic. It questions whether a \u2018cosmopolitan\u2019 dinosaur fauna ever existed, and corroborates that vicariance, extinction and dispersal did not operate uniformly in time or under uniform conditions during the Mesozoic. Their relative importance is best measured in narrow time slices and circumscribed geographical regions.", "keyphrases": ["sauropodomorph dinosaur", "new taxon", "dispersal"]}
{"id": "10.1111/j.1463-6395.2009.00426.x", "title": "Palaeomorphology: fossils and the inference of cladistic relationships", "abstract": "Edgecombe, G.D. 2010. Palaeomorphology: fossils and the inference of cladistic relationships. \u2014Acta Zoologica (Stockholm) 91: 72\u201380 Twenty years have passed since it was empirically demonstrated that inclusion of extinct taxa could overturn a phylogenetic hypothesis formulated upon extant taxa alone, challenging Colin Patterson\u2019s bold conjecture that this phenomenon \u2018may be non-existent\u2019. Suppositions and misconceptions about missing data, often couched in terms of \u2018wildcard taxa\u2019 and \u2018the missing data problem\u2019, continue to cloud the literature on the topic of fossils and phylogenetics. Comparisons of real data sets show that no ap riori(or indeed a posteriori) decisions can be made about amounts of missing data and most properties of cladograms, and both simulated and real data sets demonstrate that even highly incomplete taxa can impact on relationships. The exclusion of fossils from phylogenetic analyses is neither theoretically nor empirically defensible.", "keyphrases": ["inference", "cladistic relationship", "palaeomorphology"]}
{"id": "paleo.007483", "title": "AUTECOLOGY AND THE FILLING OF ECOSPACE: KEY METAZOAN RADIATIONS", "abstract": "Abstract:\u2002 All possible combinations of six tiering positions in relation to the substratum/water interface, six motility levels and six feeding strategies define a complete theoretical ecospace of 216 potential modes of life for marine animals. The number of modes of life actually utilized specifies realized ecospace. Owing to constraints of effectiveness and efficiency the modern marine fauna utilizes only about half the potential number of modes of life, two\u2010thirds of which (62 of 92) are utilized by animals with readily preserved, mineralized hard parts. Realized ecospace has increased markedly since the early evolution of animal ecosystems. The Ediacaran fauna utilized at most 12 modes of life, with just two practised by skeletal organisms. A total of 30 modes of life are recorded in the Early and Middle Cambrian, 19 of which were utilized by skeletal organisms. The other 11 are documented from soft\u2010bodied animals preserved in the Chengjiang and Burgess Shale Konservat\u2010Lagerst\u00e4tten. The number of modes of life utilized by skeletal organisms increased by more than 50 per cent during the Ordovician radiation to a Late Ordovician total of 30. Between the Late Ordovician and the Recent the number of utilized modes of life has doubled again. The autecological and taxonomic diversity histories of the marine metazoa appear to be broadly parallel, and future studies of theoretical ecospace utilization should provide more detailed tests of pattern and process in the ecological history of the metazoa.", "keyphrases": ["ecospace", "marine fauna", "cambrian", "complexity", "life mode"]}
{"id": "10.1111/j.1502-3931.2009.00184.x", "title": "Inferring palaeoecology in extinct tremarctine bears (Carnivora, Ursidae) using geometric morphometrics", "abstract": "In this study we explore the ecomorphological patterns of extinct tremarctine bears in South America during the Great American Biotic Interchange (GABI). These patterns are used to derive palaeoautoecological inferences in extinct tremarctines and their palaeosinecological relationships within Plio-Pleistocene ecosystems. We used geometric morphometrics of landmark data to recover the shape of the craniomandibular skeleton of bears. The results reveal different ecomorphological specializations in extinct tremarctines during the Plio-Pleistocene of South America. Indeed, these bears could have increased the percentage of plant matter in their diets according with the increased diversity of large carnivores in South America after the GABI. Omnivorous bears retain the ability to behave as carnivores or herbivores depending on resource availability. This fact strongly supports that bears are one of the most ecologically and morphologically adaptable members of the large carnivore guild. Moreover, their skull morphology could reflect ecological adaptations under different selection pressures with the required evolutionary time. h Evolution, GABI, geometric morphometrics, palaeoecology, Tremarctinae.", "keyphrases": ["palaeoecology", "extinct tremarctine bear", "geometric morphometric"]}
{"id": "paleo.008984", "title": "The Extent of the Preserved Feathers on the Four-Winged Dinosaur Microraptor gui under Ultraviolet Light", "abstract": "Background The holotype of the theropod non-avian dinosaur Microraptor gui from the Early Cretaceous of China shows extensive preservation of feathers in a halo around the body and with flight feathers associated with both the fore and hindlimbs. It has been questioned as to whether or not the feathers did extend into the halo to reach the body, or had disassociated and moved before preservation. This taxon has important implications for the origin of flight in birds and the possibility of a four-winged gliding phase. Methodology/Principal Findings Examination of the specimen under ultraviolet light reveals that these feathers actually reach the body of the animal and were not disassociated from the bones. Instead they may have been chemically altered by the body tissues of the animal meaning that they did not carbonise close into the animal or more likely were covered by other decaying tissue, though evidence of their presence remains. Conclusions/Significance These UV images show that the feathers preserved on the slab are genuinely associated with the skeleton and that their arrangement and orientation is likely correct. The methods used here to reveal hidden features of the specimen may be applicable to other specimens from the fossil beds of Liaoning that produced Microraptor.", "keyphrases": ["feather", "ultraviolet light", "tissue"]}
{"id": "10.1111/J.1096-3642.2012.00862.X", "title": "Comparative osteology and phylogenetic relationships of Miocaperea pulchra, the first fossil pygmy right whale genus and species (Cetacea, Mysticeti, Neobalaenidae)", "abstract": "A fossil pygmy right whale (Cetacea, Mysticeti, Neobalaenidae) with exquisitely preserved baleen is described for the first time in the history of cetacean palaeontology, providing a wealth of information about the evolutionary history and palaeobiogeography of Neobalaenidae. This exquisitely preserved specimen is assigned to a new genus and species, Miocaperea pulchra\u00a0gen.\u00a0et\u00a0sp. nov., and differs from Caperea marginata Gray, 1846, the only living taxon currently assigned to Neobalaenidae, in details of the temporal fossa and basicranium. A thorough comparative analysis of the skeleton of M.\u00a0pulchra gen.\u00a0et\u00a0sp.\u00a0nov. and C.\u00a0marginata is also provided, and forms the basis of an extensive osteology-based phylogenetic analysis, confirming the placement of M.\u00a0pulchra gen.\u00a0et\u00a0sp.\u00a0nov. within Neobalaenidae as well as the monophyly of Neobalaenidae and Balaenidae; the phylogenetic results support the validity of the superfamily Balaenoidea. No relationship with Balaenopteroidea was found by the present study, and thus the balaenopterid-like morphological features observed in C.\u00a0marginata must have resulted from parallel evolution. The presence of M.\u00a0pulchra gen.\u00a0et\u00a0sp.\u00a0nov. around 2000\u00a0km north from the northernmost sightings of C.\u00a0marginata suggests that different ecological conditions were able to support pygmy right whale populations in what is now Peru, and that subsequent environmental change caused a southern shift in the distribution of the living neobalaenid whales. \n \n \n \n\u00a9 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166, 876\u2013911.", "keyphrases": ["fossil pygmy", "cetacea", "neobalaenidae"]}
{"id": "paleo.010027", "title": "Improving access to endogenous DNA in ancient bones and teeth", "abstract": "Poor DNA preservation is the most limiting factor in ancient genomic research. In the majority of\nancient bones and teeth, endogenous DNA molecules represent a minor fraction of the whole DNA\nextract, rendering shot-gun sequencing inefficient for obtaining genomic data. Based on ancient\nhuman bone samples from temperate and tropical environments, we show that an EDTA-based enzymatic\n\u2018pre-digestion\u2019 of powdered bone increases the proportion of endogenous DNA several\nfold. By performing the pre-digestion step between 30 min and 6 hours on five bones,\nwe observe an asymptotic increase in endogenous DNA content, with a 2.7-fold average increase\nreached at 1 hour. We repeat the experiment using a brief pre-digestion (15 or\n30 mins) on 21 ancient bones and teeth from a variety of archaeological contexts and observe\nan improvement in 16 of these. We here advocate the implementation of a brief pre-digestion step as\na standard procedure in ancient DNA extractions. Finally, we demonstrate on 14 ancient teeth that by\ntargeting the outer layer of the roots we obtain up to 14 times more endogenous DNA than when using\nthe inner dentine. Our presented methods are likely to increase the proportion of ancient samples\nthat are suitable for genome-scale characterization.", "keyphrases": ["endogenous dna", "ancient bone", "tooth"]}
{"id": "paleo.006462", "title": "Cranial Morphology of the Brachystelechid \u2018Microsaur\u2019 Quasicaecilia texana Carroll Provides New Insights into the Diversity and Evolution of Braincase Morphology in Recumbirostran \u2018Microsaurs\u2019", "abstract": "Recumbirostran \u2018microsaurs,\u2019 a group of early tetrapods from the Late Carboniferous and Early Permian, are the earliest known example of adaptation to head-first burrowing in the tetrapod fossil record. However, understanding of the diversity of fossorial adaptation within the Recumbirostra has been hindered by poor anatomical knowledge of the more divergent forms within the group. Here we report the results of \u03bcCT study of Quasicaecilia texana, a poorly-known recumbirostran with a unique, broad, shovel-like snout. The organization of the skull roof and braincase of Quasicaecilia is found to be more in line with that of other recumbirostrans than previously described, despite differences in overall shape. The braincase is found to be broadly comparable to Carrolla craddocki, with a large presphenoid that encompasses much of the interorbital septum and the columella ethmoidalis, and a single compound ossification encompassing the sphenoid, otic, and occipital regions. The recumbirostran braincase conserves general structure and topology of braincase regions and cranial nerve foramina, but it is highly variable in the number of ossifications and their extent, likely associated with the reliance on braincase ossifications to resist compression during sediment compaction and mechanical manipulation by epaxial and hypaxial musculature. Expansion of the deep ventral neck musculature in Quasicaecilia, autapomorphic among recumbirostrans, may reflect unique biomechanical function, and underscores the importance of future attention to the role of the cervical musculature in contextualizing the origin and evolution of fossoriality in recumbirostrans.", "keyphrases": ["microsaur", "braincase", "recumbirostran"]}
{"id": "10.1017/pab.2018.22", "title": "Tracing the effects of eutrophication on molluscan communities in sediment cores: outbreaks of an opportunistic species coincide with reduced bioturbation and high frequency of hypoxia in the Adriatic Sea", "abstract": "Abstract. \n Estimating the effects and timing of anthropogenic impacts on the composition of macrobenthic communities is challenging, because early twentieth-century surveys are sparse and the corresponding intervals in sedimentary sequences are mixed by bioturbation. Here, to assess the effects of eutrophication on macrobenthic communities in the northern Adriatic Sea, we account for mixing with dating of the bivalve Corbula gibba at two stations with high accumulation (Po prodelta) and one station with moderate accumulation (Isonzo prodelta). We find that, first, pervasively bioturbated muds typical of highstand conditions deposited in the early twentieth century were replaced by muds with relicts of flood layers and high content of total organic carbon (TOC) deposited in the late twentieth century at the Po prodelta. The twentieth century shelly muds at the Isonzo prodelta are amalgamated but also show an upward increase in TOC. Second, dating of C. gibba shells shows that the shift from the early to the late twentieth century is characterized by a decrease in stratigraphic disorder and by an increase in temporal resolution of assemblages from ~ 25\u201350 years to ~ 10\u201320 years in both regions. This shift reflects a decline in the depth of the fully mixed layer from more than 20 cm to a few centimeters. Third, the increase in abundance of the opportunistic species C. gibba and the loss of formerly abundant, hypoxia-sensitive species coincided with the decline in bioturbation, higher preservation of organic matter, and higher frequency of seasonal hypoxia in both regions. This depositional and ecosystem regime shift occurred in ca. A.D. 1950. Therefore, the effects of enhanced food supply on macrobenthic communities were overwhelmed by oxygen depletion, even when hypoxic conditions were limited to few weeks per year in the northern Adriatic Sea. Preservation of trends in molluscan abundance and flood events in cores was enhanced by higher frequency of hypoxia that reduced bioturbation in the late twentieth century.", "keyphrases": ["eutrophication", "sediment core", "bioturbation"]}
{"id": "10.1073/pnas.1610726113", "title": "Sex and the shifting biodiversity dynamics of marine animals in deep time", "abstract": "Significance Fertilization mechanisms explain broad patterns in the taxonomic distribution of diversity in marine animals, as argued previously for land plants. We argue that fertilization via copulation (or some other significant interaction among adults) permits additional mechanisms of reproductive isolation and smaller population sizes relative to fertilization via the broadcasting of sperm into the water, thus enhancing diversification potential. Maximum-likelihood modeling of paleontological data indicates that the diversity of sperm broadcasters has been limited by diversity-dependent factors for the last 450 million years. In contrast, animals that copulate, etc., were also limited until the Cretaceous and then radiated dramatically, coincident with apparent major changes in marine productivity. Fertilization may have acted synergistically with ecological specialization in promoting diversification, particularly in predators. The fossil record of marine animals suggests that diversity-dependent processes exerted strong control on biodiversification: after the Ordovician Radiation, genus richness did not trend for hundreds of millions of years. However, diversity subsequently rose dramatically in the Cretaceous and Cenozoic (145 million years ago\u2013present), indicating that limits on diversification can be overcome by ecological or evolutionary change. Here, we show that the Cretaceous\u2013Cenozoic radiation was driven by increased diversification in animals that transfer sperm between adults during fertilization, whereas animals that broadcast sperm into the water column have not changed significantly in richness since the Late Ordovician (\u223c450 million years ago). We argue that the former group radiated in part because directed sperm transfer permits smaller population sizes and additional modes of prezygotic isolation, as has been argued previously for the coincident radiation of angiosperms. Directed sperm transfer tends to co-occur with many ecological traits, such as a predatory lifestyle. Ecological specialization likely operated synergistically with mode of fertilization in driving the diversification that began during the Mesozoic marine revolution. Plausibly, the ultimate driver of diversification was an increase in food availability, but its effects on the fauna were regulated by fundamental reproductive and ecological traits.", "keyphrases": ["marine animal", "fertilization", "diversification", "water column"]}
{"id": "paleo.008454", "title": "Developmental and evolutionary novelty in the serrated teeth of theropod dinosaurs", "abstract": "Tooth morphology and development can provide valuable insights into the feeding behaviour and evolution of extinct organisms. The teeth of Theropoda, the only clade of predominantly predatory dinosaurs, are characterized by ziphodonty, the presence of serrations (denticles) on their cutting edges. Known today only in varanid lizards, ziphodonty is much more pervasive in the fossil record.\nHere we present the first model for the development of ziphodont teeth in theropods through histological, SEM, and SR-FTIR analyses, revealing that structures previously hypothesized to prevent tooth breakage instead first evolved to shape and maintain the characteristic denticles through the life of the tooth. We show that this novel complex of dental morphology and tissues characterizes Theropoda, with the exception of species with modified feeding behaviours, suggesting that these characters are important for facilitating the hypercarnivorous diet of most theropods. This adaptation may have played an important role in the initial radiation and subsequent success of theropods as terrestrial apex predators.", "keyphrases": ["tooth", "valuable insight", "feeding behaviour", "extinct organism"]}
{"id": "10.1111/j.1096-3642.2008.00402.x", "title": "The effects of locomotion on the structural characteristics of avian limb bones", "abstract": "Despite the wide range of locomotor adaptations in birds, little detailed attention has been given to the relationships between the quantitative structural characteristics of avian limb bones and bird behaviour. Possible differences in forelimb relative to hindlimb strength across species have been especially neglected. We generated cross-sectional, geometric data from peripheral quantitative computed tomography scans of the humerus and femur of 127 avian skeletons, representing 15 species of extant birds in 13 families. The sample includes terrestrial runners, arboreal perchers, hindlimb-propelled divers, forelimb-propelled divers and dynamic soarers. The hindlimb-propelled diving class includes a recently flightless island form. Our results demonstrate that locomotor dynamics can be differentiated in most cases based on cross-sectional properties, and that structural proportions are often more informative than bone length proportions for determining behaviour and locomotion. Recently flightless forms, for example, are more easily distinguished using structural ratios than using length ratios. A proper phylogenetic context is important for correctly interpreting structural characteristics, especially for recently flightless forms. Some of the most extreme adaptations to mechanical loading are seen in aquatic forms. Penguins have forelimbs adapted to very high loads. Aquatic species differ from non-aquatic species on the basis of relative cortical thickness. The combination of bone structural strength and relative cortical area of the humerus successfully differentiates all of our locomotor groups. The methods used in this study are highly applicable to fossil taxa, for which morphology is known but behaviour is not. The use of bone structural characteristics is particularly useful in palaeontology not only because it generates strong signals for many locomotor guilds, but also because analysing such traits does not require knowledge of body mass, which can be difficult to estimate reliably for fossil taxa. \u00a9 2008 The Linnean Society of London, Zoological Journal of the Linnean Society, 2008, 153, 601\u2010624.", "keyphrases": ["locomotion", "structural characteristic", "avian limb bone"]}
{"id": "paleo.004553", "title": "Bone histology of Proneusticosaurus (Diapsida, Eosauropterygia) from the Middle Triassic of Poland reveals new insights into taxonomic affinities", "abstract": "The status of Proneusticosaurus silesiacus from the Lower Muschelkalk (lower Anisian) of Poland is controversially discussed. Its femur was histologically sampled to learn more about its taxonomic affinities and life style. It shows a reduced central medullary cavity surrounded by a narrow medullary region and followed by a thick compact cortex, displaying strong osteosclerosis. The tissue type can be summarized as lamellar-zonal. The inner third of the cortex consists of well vascularized parallel-fibred bone and is interpreted as a phase of juvenile growth, whereas the middle and outer cortex is made of highly organized parallel-fibred to lamellar bone. Except for the inner cortex and local accumulations of longitudinally primary osteons in the middle cortex, the femur is widely avascular. The cortex of P. silesiacus is regularly stratified by rest lines. Altogether seven annual growth cycles are counted. The very low growth rate of P. silesiacus, as deduced from tissue type, makes taxonomical affinities to Nothosaurus spp. or basal pistosauroids (i.e., humeri of aff. Cymatosaurus sp.) very unlikely. Proneusticosaurus silesiacus femoral histology does also not match any of the here studied femora of Eosauropterygia indet. Proneusticosaurus silesiacus shares similar low growth rates, the osteosclerotic femur, as well as pachyostotic vertebrae and ribs with the pachypleurosaurs Dactylosaurus gracilis and Neusticosaurus spp. and with the nothosaur Lariosaurus sp. These features are, however, most likely convergent and reflect the degree of secondary aquatic adaptation in shallow marine inhabitants. The high organized and low vascularized tissue, the implied low growth rate, the plesiomorphic femur morphology, and the strongly inclined zygapophyses of the vertebrae (contra roughly horizontal zygapophyses in other Eosauropterygia), makes P. silesiacus unique and evidence that this genus represents a valid genus within early Eosauropterygia. Proneusticosaurus silesiacus might represent one of the most basal members of Eosauropterygia so far known.\n", "keyphrases": ["proneusticosaurus", "eosauropterygia", "taxonomic affinity", "pachypleurosaur"]}
{"id": "10.1017/S0022336000040750", "title": "The skull and taxonomy of Mixosaurus (Ichthyopterygia)", "abstract": "Mixosaurus, a Middle Triassic ichthyopterygian, has traditionally been recognized as a typically primitive ichthyopterygian, but this view was recently questioned. Examination of the skull of Mixosaurus revealed many features to confirm this doubt. Its cranial characters, such as the parietal ridge and short supratemporal process of the parietal, are shared with derived ichthyopterygians from the Jurassic. Mixosaurus also has features that are derived within the Ichthyopterygia and unique to the genus, such as a long sagittal crest reaching the nasal, and an expanded anterior terrace of the upper temporal fenestra that also reaches the nasal. Phalarodon, Contectopalatus, and Sangiorgiosaurus are all considered as junior synonyms of Mixosaurus. The supratemporal, squamosal, and quadratojugal are all present in Mixosaurus atavus, as in basal ichthyopterygians. Because all basal ichthyopterygians, and even some derived ichthyopterygians from the Jurassic, have these three elements, the absence of the squamosal in Ichthyosaurus and Platypterygius should be considered derived if it is not preservational.", "keyphrases": ["skull", "mixosaurus", "ichthyopterygia"]}
{"id": "10.1017/pab.2016.34", "title": "Comparing cal3 and other a posteriori time-scaling approaches in a case study with the pterocephaliid trilobites", "abstract": "Abstract. Reconstructing the tree of life involvesmore than identifying relationships among lineages; it also entails accurately estimating when lineages diverged. Paleontologists typically scale cladograms to time a posteriori by direct reference to first appearances of taxa in the stratigraphic record. Some approaches use probabilistic models of branching, extinction, and sampling processes to date samples of trees, such as the recently developed cal3 method, which stochastically draws divergence dates given a set of rates for those processes. However, these models require estimates of the rates of those processes, which may be hard to obtain, particularly for sampling. Here, we contrast the use of cal3 and other a posteriori time-scaling approaches by examining a previous study that documented a decelerating rate of morphological evolution in pterocephaliid trilobites. Although aspects of the data set make estimation of branching, extinction, and sampling rates difficult, we use a multifaceted approach to calculate and evaluate the rate estimates needed for applying cal3. In agreement with previous simulation studies, we find that the choice of phylogenetic dating method impacts downstream macroevolutionary conclusions. We also find contradictory evolutionary inferences between analyses on ancestor\u2014descendant contrasts (based on ancestor trait reconstruction methods) and maximum-likelihood parameter estimates. Ancestral taxon inference in cal3 corroborates previously hypothesized ancestor\u2014descendant sequences, but cal3 suggests greater support for budding cladogenesis than anagenesis. This case study demonstrates the potential and wide applicability of the cal3 method and the benefits afforded by choosing cal3 over simpler a posteriori time-scaling approaches.", "keyphrases": ["cal3", "posteriori time-scaling approach", "case study"]}
{"id": "paleo.004028", "title": "PALEOBOTANY AND SEDIMENTOLOGY OF LATE OLIGOCENE TERRESTRIAL STRATA FROM THE NORTHWESTERN ETHIOPIAN PLATEAU", "abstract": "This paper describes the sedimentology and paleobotany of a Late Oligocene (27.36 \u00b1 0.11 Ma) succession of volcaniclastic strata from the Margargaria River region, northwestern Ethiopian Plateau. Sedimentology indicates fluvial deposition of clay-and silt-rich strata during the early sedimentary phases, whereas organic-rich deposits and massive and fluvially-reworked ash layers are increasingly more common in the middle and upper parts of the succession, respectively. Periods of interrupted deposition are indicated by three paleosol types present in the basal and middle parts of the succession. Paleobotany documents an exclusively angiosperm flora typical of riparian environments in the lower parts of the succession, and a flora dominated by ferns and a few angiosperm taxa typical of disturbed environments in the middle and upper parts. Sedimentology and paleobotany, combined, indicate a riparian environment inhabited by angiosperms for the lower part of the succession, characterized by rather calm deposition by meandering streams. The middle and upper parts of the succession represent transient environments colonized by pioneer vegetation consisting of a diverse fern community and fewer pioneer angiosperms, characterized by deposition of organic-and ash-rich strata in situ in ephemeral ponds and by small-scale crevasse-like channels and by aereal means on the landscape, respectively. Physiographic changes are interpreted to have resulted directly from the influence of volcanism on the surface environment. In summary, this study shows that the volcanic activity associated with the elevation of the northwestern Ethiopian Plateau during the Oligocene repeatedly influenced the development of plant communities and paleoenvironments, favoring the succession of heterogeneous ecosystems on short temporal and spatial scales. Finally, this study is the first that combines paleobotanical and sedimentological data for paleoenvironmental reconstruction and understanding of plant community dynamics in Paleogene deposits from Africa, and it demonstrates the advantages of a multiproxy approach for assessment of paleoecosystem dynamics on an unstable landscape.", "keyphrases": ["sedimentology", "oligocene", "northwestern ethiopian plateau"]}
{"id": "10.1130/b35088.1", "title": "Strontium isotope stratigraphy and paleomagnetic age constraints on the evolution history of coral reef islands, northern South China Sea", "abstract": "\n Understanding the history of the response of coral reefs to past climate changes can provide valuable information for predicting the future response of modern reefs. However, dating such ancient biotic carbonate is still challenging because of its sensitivity to diagenetic alteration processes, scarcity of well-preserved fossils, and low magnetic mineral content. There have been a long debates about the origin and evolutionary history of coral reefs in the northern South China Sea, mainly due to the lack of direct and reliable age constraints. This provides us with a good opportunity to verify the practicability of different dating approaches, especially the strontium (Sr) isotope analysis of bulk carbonate. Here, we retrieved a 972.55-m-long core from the Xisha Islands to provide a credible chronologic constraint on the carbonate platform evolution. The lithostratigraphy, strontium isotope stratigraphy, and magnetostratigraphy were analyzed throughout the whole reef sequence. The lithostratigraphic results show that the 873.55 m reef sequence developed on an ancient volcaniclastic basement and experienced multiple evolutionary phases. The 87Sr/86Sr results of all 100 bulk carbonate samples vary from 0.708506 to 0.709168 and show a monotonic increase with decreasing depth, except for a few outliers. Trace-element criteria and stable isotope (\u03b418O and \u03b413C) methods were applied to these bulk carbonate samples, and results imply that the primary or near-primary seawater 87Sr/86Sr values were likely preserved, although different degrees of diagenetic alteration occurred. In addition, the paleomagnetic results indicate 10 normal polarity and eight reversed polarity magnetozones. Based on the 87Sr/86Sr ratios of the selected 58 samples and paleomagnetic reconstruction of polarity reversals, the bottom of the reef sequence is dated to 19.6 Ma, and the observed polarity chronozones extend from chron C6 (19.722\u201318.748 Ma) at 866.60 m to present at the top. Based on the new data, we propose a new chronologic framework for the evolutionary history of the reef islands, where: (1) the reefs initiated in the early Miocene (19.6 Ma) and were drowned until 16.26 Ma; (2) during 16.26\u201310.66 Ma, lagoon to lagoon slope environments prevailed; (3) the lagoon environment progressively transformed into a reef crest environment from 10.66 to 4.36 Ma and 4.36 to 1.59 Ma; and (4) the reef started to be drowned again during 1.59\u20130 Ma. Our study provides a new and reliable chronologic constraint on the general evolutionary history of the reef islands in the northern South China Sea. Furthermore, the 87Sr/86Sr results from bulk carbonate indicate that strontium isotope stratigraphy is a powerful dating tool only when rigid sample selection, sequential leaching procedures, and strict trace-element and isotopic criteria are applied.", "keyphrases": ["reef island", "south china sea", "strontium isotope stratigraphy"]}
{"id": "paleo.003220", "title": "Calcaneal proportions in primates and locomotor inferences in Anchomomys and other Palaeogene Euprimates", "abstract": "Foot proportions, and in particular the lengthening of the tarsal elements, play a fundamental role in the discussion on the locomotor adaptations of Palaeogene primates. The elongation of the distal portion of the tarsus, particularly the anterior part of the calcaneus, is frequently interpreted as an adaptation to leaping and has played a fundamental role in the reconstruction of the locomotor adaptations of the earliest primates. Here, we report an allometric analysis of calcaneal proportions in primates and other mammals, in order to determine the actual differences in calcaneal proportions. This analysis reveals that primates as a group display a relatively longer distal calcaneus, relative to both total calcaneal length and body mass, when compared with other mammals. Contrary to current expectations, morphofunctional analysis indicates that a moderate degree of calcaneal elongation is not an adaptation to leaping, but it is merely a compensatory mechanism to recover the lost load arm (metatarsal length) when the foot adopts a grasping function, in order to maintain the same locomotor efficiency. Leaping can be inferred only when anterior calcaneal length departs from the scaling of non-specialized primate groups. The role of leaping on the inferred locomotor repertoire of earliest primates needs to be revised considering the results of this work.", "keyphrases": ["primate", "foot", "leaping", "calcaneal proportion"]}
{"id": "paleo.002139", "title": "Dominican amber net-winged beetles suggest stable paleoenvironment as a driver for conserved morphology in a paedomorphic lineage", "abstract": "Paedomorphosis is a heterochronic syndrome in which adult individuals display features of their immature forms. In beetles, this phenomenon occurs widely in the superfamily Elateroidea, including the net-winged beetles (Lycidae), and, due to the usual flightlessness of paedomorphic females, it is hypothesized to cause speciation rates higher than in non-paedomorphic lineages. However, some fossils of paedomorphic lycids do not support this with palaeobiological data. Discovery of new Lycidae fossils attributed to the West Indian extant paedomorphic genus Cessator Kazantsev in the Dominican amber also suggests morphological stasis within this genus in the Greater Antilles. We describe Cessator anachronicus Ferreira and Ivie, sp. nov. based on adult males, as well as the first ever recorded fossil net-winged beetle larva of the same genus. We propose that the relatively young age of the studied fossils combined with the stable conditions in the forest floor of the Greater Antilles through the last tens of million years could explain the exceptionally conserved morphology in the net-winged beetles affected by the paedomorphic syndrome.", "keyphrases": ["net-winged beetle", "morphology", "paedomorphosis", "elateroidea", "dominican amber"]}
{"id": "paleo.009914", "title": "Increased Atmospheric SO2 Detected from Changes in Leaf Physiognomy across the Triassic\u2013Jurassic Boundary Interval of East Greenland", "abstract": "The Triassic\u2013Jurassic boundary (Tr\u2013J; \u223c201 Ma) is marked by a doubling in the concentration of atmospheric CO2, rising temperatures, and ecosystem instability. This appears to have been driven by a major perturbation in the global carbon cycle due to massive volcanism in the Central Atlantic Magmatic Province. It is hypothesized that this volcanism also likely delivered sulphur dioxide (SO2) to the atmosphere. The role that SO2 may have played in leading to ecosystem instability at the time has not received much attention. To date, little direct evidence has been presented from the fossil record capable of implicating SO2 as a cause of plant extinctions at this time. In order to address this, we performed a physiognomic leaf analysis on well-preserved fossil leaves, including Ginkgoales, bennettites, and conifers from nine plant beds that span the Tr\u2013J boundary at Astartekl\u00f8ft, East Greenland. The physiognomic responses of fossil taxa were compared to the leaf size and shape variations observed in nearest living equivalent taxa exposed to simulated palaeoatmospheric treatments in controlled environment chambers. The modern taxa showed a statistically significant increase in leaf roundness when fumigated with SO2. A similar increase in leaf roundness was also observed in the Tr\u2013J fossil taxa immediately prior to a sudden decrease in their relative abundances at Astartekl\u00f8ft. This research reveals that increases in atmospheric SO2 can likely be traced in the fossil record by analyzing physiognomic changes in fossil leaves. A pattern of relative abundance decline following increased leaf roundness for all six fossil taxa investigated supports the hypothesis that SO2 had a significant role in Tr\u2013J plant extinctions. This finding highlights that the role of SO2 in plant biodiversity declines across other major geological boundaries coinciding with global scale volcanism should be further explored using leaf physiognomy.", "keyphrases": ["atmospheric so2", "atmosphere", "leaf physiognomy", "east greenland", "environment chamber"]}
{"id": "10.1111/j.1475-4983.2012.01131.x", "title": "Ontogeny and microstructure of the enigmatic Cambrian tommotiid Sunnaginia Missarzhevsky, 1969", "abstract": "Abstract:\u2002 The tommotiids are a significant component of the earliest skeletal animal remains in the fossil record, occurring in large numbers in the Lower Cambrian. Sclerites of the tommotiid genus Sunnaginia have been implicated as integral to hypotheses regarding the evolution of the brachiopod body plan, with a morphology intermediate between the unspecialized sclerites of the tubular Eccentrotheca and the specialized sclerites of the tannuolinids. Abundant Sunnaginia ?imbricata sclerites, of a broad ontogenetic spectrum, were recovered from the Comley Limestone, Lower Cambrian (Stages 3\u20134), Shropshire, UK and compared to Sunnaginia imbricata from the Aldan River, Siberia (uppermost Tommotian). New microstructural data, collected using synchrotron radiation X\u2010ray tomographic microscopy, reveal a unique microstructure for Sunnaginia ?imbricata sclerites among the tommotiids; interlamellar cavities spanned by a series of continuous pillars, giving a colonnaded appearance contrasting to that of S. imbricata. These data refute the inclusion of Eccentrotheca within the Sunnaginiidae and highlight the need for a revision of suprageneric classification of the tommotiids. Rather, structural similarities between Sunnaginia sclerites and those of the tannuolinids suggest a close affinity to this group. Recent phylogenetic hypotheses place the tannuolinids as stem\u2010linguliform brachiopods, with Paterimitra plus the paterinid (and possibly rhynchonelliform) brachiopods as their sister group. Our new data therefore resolve Sunnaginia as close to the node defining crown\u2010Brachiopoda. However, the characters supporting this phylogenetic scheme cannot be consistently applied to all taxa, nor do they define a series of nested clades. We therefore suggest that a more thorough phylogenetic analysis is required in the light of the data presented here and other recent descriptions.", "keyphrases": ["microstructure", "tommotiid", "brachiopod"]}
{"id": "10.1636/SH09-07.1", "title": "Scorpion taphonomy: criteria for distinguishing fossil scorpion molts and carcasses", "abstract": "Abstract The ability to distinguish fossil arthropod carcasses from their molts is necessary for a more complete understanding of the arthropod fossil record and for more accurately assessing the role of fossil arthropods in paleoecosystems. Taphonomic characteristics, e.g., recurrent patterns of disarticulation of exoskeletal elements, are the primary data that have been used to differentiate fossil exuvia and fossil carcasses among arthropods. This study documents recurrent taphonomic patterns in modern scorpion carcasses and molts and extends these patterns to the fossil record to define criteria by which fossil scorpion molts might be distinguished from fossil scorpion carcasses. The three most useful and statistically significant characters in making the scorpion carcass/molt distinction are: position of the chelicerae (drawn in or extended); position of walking legs (folded or splayed); and body line (straight or curved). Two other characteristics, the position of pedipalps and presence or absence of telescoped segments, approach statistical significance and are also potentially useful. Disarticulation data are not as useful for distinguishing fossil scorpion molts and carcasses, because there are no statistically significant differences in length of time to total disarticulation or in the sequence of disarticulation between scorpion molts and carcasses. Among extant arthropods, scorpions possess the body plan most similar to that of the extinct eurypterids. Therefore, the taphonomic criteria developed for distinguishing fossil scorpion molts and carcasses may have implications for understanding molting among eurypterids.", "keyphrases": ["fossil scorpion molt", "carcass", "criterion"]}
{"id": "paleo.003702", "title": "Nomenclature, Comparative Anatomy, and Evolution of the Reflected Lamina of the Angular in Non-Mammalian Synapsids", "abstract": "ABSTRACT The reflected lamina of the angular has long been portrayed as a key component in understanding the evolution of the mammalian mandible and middle ear, yet the function of this structure in non-mammalian therapsids remains uncertain. We undertake a broad scale survey of two aspects of the reflected lamina that have been poorly characterized: the ridges and fossae on its lateral surface and the extent of the underlying angular cleft. These two features were visualized in a wide range of therapsids using CT data from the literature and blue light surface scanning. Most species exhibit a clade-specific pattern of surface topography, although dicynodonts are highly variable. A striking similarity in the general number and orientation of fossae and ridges is seen between the otherwise disparate therapsid clades, and we propose homologies in these surface features across Therapsida. These features may serve as useful phylogenetic characters in analyses of the relationships among the major therapsid clades. The angular cleft does not underlie all of what is often referred to as the \u2018reflected lamina\u2019 in the literature, and an updated definition of this term is provided. Several therapsid groups independently expanded the angular cleft to further separate the reflected lamina from the angular body. We discuss some functional consequences of our findings and note inconsistency between proposed clade-specific muscle attachment sites and the presence of homologous fossae and ridges across much of Therapsida.", "keyphrases": ["comparative anatomy", "angular", "non-mammalian synapsid"]}
{"id": "10.1111/brv.12557", "title": "The palaeobiology of belemnites \u2013 foundation for the interpretation of rostrum geochemistry", "abstract": "Belemnites are an extinct group of Mesozoic coleoid cephalopods with a fossil record ranging from the early Late Triassic [about 240 million years ago (Mya)] to the Cretaceous/Palaeogene boundary (65 Mya). Belemnites were widely distributed, highly abundant and diverse, and an important component of Mesozoic marine food webs. Their internal shells, specifically their low\u2010Mg calcite rostra, have been used as palaeoenvironmental carbonate archives for the last 70\u2009years. This is primarily due to the assumption that the rostrum calcite formed in equilibrium with the oxygen isotope composition of ambient sea water. Of prime importance for the reliable interpretation of isotope data derived from these biogenic carbonates is a robust reconstruction of the palaeobiology of their producers. Here we provide a critical assessment of published reconstructions of belemnite soft\u2010body organization and their lifestyle and habitats. Different lines of evidence, including sedimentological, geochemical, morphological, and biomechanical data, point towards an outer shelf habitat of belemnites, for some taxa also including the littoral area. Belemnite habitat temperatures, oxygen content, salinities, and life span are constrained based on observations of the ecology and life history of modern coleoids. Belemnite habitat depth might have been largely controlled by food and temperature, with a temperature optimum between 10\u00b0C and 30\u00b0C. The distribution of modern coleoids is for most species restricted to well\u2010oxygenated water masses and a salinity between 27 and 37 psu. The trophic position of belemnites as both predators and prey is documented by unique fossil finds of stomach contents and soft tissue preservation, such as jaws, hooks, and ink sacs. Belemnites were medium\u2010sized predators in the epipelagic zone (not deeper than \u223c200 m) hunting for crustaceans, other cephalopods, and fishes. Taxa with elongated rostra probably were fast and highly manoeuvrable swimmers. Forms with conical rostra represent slow but highly manoeuvrable swimmers, and forms with depressed rostra likely had a bottom\u2010related life habit. Predators of adult belemnites were sharks, bony fishes, and marine reptiles. Belemnites, like most of the modern coleoids, were relatively short lived, most likely living only for 1\u20132\u2009years. Understanding the biomineralization of belemnite rostra is highly relevant for an improved interpretation of their geochemistry. Here we confirm that belemnite rostra are composed of low Mg\u2010calcite fibres, but they do not contain distinct types of laminae. These fibres are composed of two distinct calcite phases. One phase is a filigree network of tetrahedral organic\u2010rich calcite and the second phase is represented by organic\u2010poor calcite.", "keyphrases": ["palaeobiology", "belemnite", "extinct group", "palaeoenvironmental reconstruction"]}
{"id": "paleo.009403", "title": "Closing the gap between rocks and clocks using total-evidence dating", "abstract": "Total-evidence dating (TED) allows evolutionary biologists to incorporate a wide range of dating information into a unified statistical analysis. One might expect this to improve the agreement between rocks and clocks but this is not necessarily the case. We explore the reasons for such discordance using a mammalian dataset with rich molecular, morphological and fossil information. There is strong conflict in this dataset between morphology and molecules under standard stochastic models. This causes TED to push divergence events back in time when using inadequate models or vague priors, a phenomenon we term \u2018deep root attraction\u2019 (DRA). We identify several causes of DRA. Failure to account for diversified sampling results in dramatic DRA, but this can be addressed using existing techniques. Inadequate morphological models also appear to be a major contributor to DRA. The major reason seems to be that current models do not account for dependencies among morphological characters, causing distorted topology and branch length estimates. This is particularly problematic for huge morphological datasets, which may contain large numbers of correlated characters. Finally, diversification and fossil sampling priors that do not incorporate all the available background information can contribute to DRA, but these priors can also be used to compensate for DRA. Specifically, we show that DRA in the mammalian dataset can be addressed by introducing a modest extra penalty for ghost lineages that are unobserved in the fossil record, for instance by assuming rapid diversification, rare extinction or high fossil sampling rate; any of these assumptions produces highly congruent divergence time estimates with a minimal gap between rocks and clocks. Under these conditions, fossils have a stabilizing influence on divergence time estimates and significantly increase the precision of those estimates, which are generally close to the dates suggested by palaeontologists. This article is part of the themed issue \u2018Dating species divergences using rocks and clocks\u2019.", "keyphrases": ["rock", "clock", "total-evidence", "conflict", "standard stochastic model"]}
{"id": "paleo.008072", "title": "Early Jurassic bennettitalean reproductive structures of Romania", "abstract": "The Romanian Early Jurassic (Hettangian-Sinemurian) floras represent a key element of the Eurosinian Province in which the Williamsoniaceae (Bennettitales) are well represented by vegetative remains (leaves, stems, roots) and reproductive structures. Up to the present, Early Jurassic bennettitalean reproductive structures have been found at only two localities in Romania: Anina and Doman. These localities belong to the Re\u015fi\u0163a Basin, Getic Nappe, South Carpathians, Romania, with Anina considered to be the best Romanian Early Jurassic locality in terms of diversity and preservation of fossil plants and animals, i.e. a fossil Lagerst\u00e4tte. This paper deals with all bennettitalean reproductive structures identified to date. These belong to the Steierdorf Formation, Valea Tereziei Member, and are Sinemurian in age. In total, 32 rare hand specimens (compressions and casts) have been studied and the following taxa identified: Williamsonia banatica", "keyphrases": ["reproductive structure", "romania", "early jurassic bennettitalean"]}
{"id": "10.1371/journal.pone.0215369", "title": "ZooArchNet: Connecting zooarchaeological specimens to the biodiversity and archaeology data networks", "abstract": "Interdisciplinary collaborations and data sharing are essential to addressing the long history of human-environmental interactions underlying the modern biodiversity crisis. Such collaborations are increasingly facilitated by, and dependent upon, sharing open access data from a variety of disciplinary communities and data sources, including those within biology, paleontology, and archaeology. Significant advances in biodiversity open data sharing have focused on neontological and paleontological specimen records, making available over a billion records through the Global Biodiversity Information Facility. But to date, less effort has been placed on the integration of important archaeological sources of biodiversity, such as zooarchaeological specimens. Zooarchaeological specimens are rich with both biological and cultural heritage data documenting nearly all phases of human interaction with animals and the surrounding environment through time, filling a critical gap between paleontological and neontological sources of data within biodiversity networks. Here we describe technical advances for mobilizing zooarchaeological specimen-specific biological and cultural data. In particular, we demonstrate adaptations in the workflow used by biodiversity publisher VertNet to mobilize Darwin Core formatted zooarchaeological data to the GBIF network. We also show how a linked open data approach can be used to connect existing biodiversity publishing mechanisms with archaeoinformatics publishing mechanisms through collaboration with the Open Context platform. Examples of ZooArchNet published datasets are used to show the efficacy of creating this critically needed bridge between biological and archaeological sources of open access data. These technical advances and efforts to support data publication are placed in the larger context of ZooarchNet, a new project meant to build community around new approaches to interconnect zoorchaeological data and knowledge across disciplines.", "keyphrases": ["zooarchaeological specimen", "biodiversity", "zooarchnet"]}
{"id": "paleo.006866", "title": "An early chondrichthyan and the evolutionary assembly of a shark body plan", "abstract": "Although relationships among the major groups of living gnathostomes are well established, the relatedness of early jawed vertebrates to modern clades is intensely debated. Here, we provide a new description of Gladbachus, a Middle Devonian (Givetian approx. 385-million-year-old) stem chondrichthyan from Germany, and one of the very few early chondrichthyans in which substantial portions of the endoskeleton are preserved. Tomographic and histological techniques reveal new details of the gill skeleton, hyoid arch and jaws, neurocranium, cartilage, scales and teeth. Despite many features resembling placoderm or osteichthyan conditions, phylogenetic analysis confirms Gladbachus as a stem chondrichthyan and corroborates hypotheses that all acanthodians are stem chondrichthyans. The unfamiliar character combination displayed by Gladbachus, alongside conditions observed in acanthodians, implies that pre-Devonian stem chondrichthyans are severely under-sampled and strongly supports indications from isolated scales that the gnathostome crown group originated at the latest by the early Silurian (approx. 440 Ma). Moreover, phylogenetic results highlight the likely convergent evolution of conventional chondrichthyan conditions among earliest members of this primary gnathostome division, while skeletal morphology points towards the likely suspension feeding habits of Gladbachus, suggesting a functional origin of the gill slit condition characteristic of the vast majority of living and fossil chondrichthyans.", "keyphrases": ["chondrichthyan", "germany", "phylogenetic analysis", "acanthodian"]}
{"id": "paleo.012495", "title": "Bilaterally symmetric axes with rhizoids composed the rooting structure of the common ancestor of vascular plants", "abstract": "There are two general types of rooting systems in extant land plants: gametophyte rhizoids and sporophyte root axes. These structures carry out the rooting function in the free-living stage of almost all land plant gametophytes and sporophytes, respectively. Extant vascular plants develop a dominant, free-living sporophyte on which roots form, with the exception of a small number of taxa that have secondarily lost roots. However, fossil evidence indicates that early vascular plants did not develop sporophyte roots. We propose that the common ancestor of vascular plants developed a unique rooting system\u2014rhizoidal sporophyte axes. Here we present a synthesis and reinterpretation of the rootless sporophytes of Horneophyton lignieri, Aglaophyton majus, Rhynia gwynne-vaughanii and Nothia aphylla preserved in the Rhynie chert. We show that the sporophyte rooting structures of all four plants comprised regions of plagiotropic (horizontal) axes that developed unicellular rhizoids on their underside. These regions of axes with rhizoids developed bilateral symmetry making them distinct from the other regions which were radially symmetrical. We hypothesize that rhizoidal sporophyte axes constituted the rooting structures in the common ancestor of vascular plants because the phylogenetic positions of these plants span the origin of the vascular lineage. This article is part of a discussion meeting issue \u2018The Rhynie cherts: our earliest terrestrial ecosystem revisited\u2019.", "keyphrases": ["rhizoids", "vascular plant", "axis"]}
{"id": "10.3406/geolm.1974.928", "title": "Aragonitic shell structures in the rudist Biradiolites, and some palaeobiological inferences", "abstract": "Skelton P., 1973. Aragonitic shell structures in the rudist Biradiolites, and some palaeobiological inferences. (Sur la preservation de structures aragonitiques dans la coquille du genre Biradiolites (Rudiste) \u2014 Implications paleobiologiques). Des echantillons de Biradiolites angulosissimus Toucas, provenant du Santonien du Massif de la Ste Baume, montrent dans leur coquille des structures aragonitiques. Trois couches peuvent etre distinguees : \u2014 Une couche externe formee de prismes de calcite, compacte dans la -valve gauche, cellulaire dans la valve droite. \u2014 Une couche moyenne aragonitique de structure \"crosse d-lamellar\" doublant la couche externe a l'interieur de la cavite generale formant les dents de la valve gauche, et les fossettes de la valve droite. \u2014 Une couche interne aragonitique de structure \"complex crossed-lamellar\", comblant le fond de la cavite generale, et constituant les apophyses myophores. En outre on observe des prismes myostracaux d'aragonite bien developpes sur les apophyses myophores, et egalement entre les couches moyennes et interne de la valve droite, et sur la surface ventrale de l'appareil cardinal de la valve gauche. Le stade initial est de type spirogyre avec une charniere de type monopleuride et probablement un ligament de type diceratide. Ces caracteres disparaissent au stade adulte. La couche calci tique n'apparait que tardivement. La preservation de l'Aragonite semble favorisee par le caractere reducteur des sediments. Les muscles adducteurs de B. angulosissimus etaient tres courts. Il n'y avait pas de fusion entre les deux lobes du manteau sur la commissure des deux valves. Les Biradiolitinae sont proches des Monopleuridae. La couche calcitique semble etre une addition ontogenique et n'existe peut etre pas chez les ancetres des Rudistes.", "keyphrases": ["rudist biradiolites", "palaeobiological inference", "aragonitic shell structure"]}
{"id": "10.1080/02724634.2019.1593185", "title": "A New Genus and Species of Extinct Ground Shark, \u2020Diprosopovenator Hilperti, Gen. Et Sp. Nov. (Carcharhiniformes, \u2020Pseudoscyliorhinidae, Fam. Nov.), from The Upper Cretaceous of Germany", "abstract": "ABSTRACT We describe a new genus and species of extinct ground shark, \u2020Diprosopovenator hilperti, gen. et sp. nov. (Elasmobranchii, Carcharhiniformes), based on a single incomplete skeleton with dentition recovered from basinal marine late Cenomanian (Metoicoceras geslinianum ammonite zone) organic-rich deposits of northern Germany. The new carcharhiniform is characterized by a unique combination of dental morphologies, indicating close architectural resemblance to the family Scyliorhinidae (catsharks). However, the very distinct tooth root morphology readily separates the new taxon from all other scyliorhinids. The extinct Cretaceous carcharhiniform \u2020Pseudoscyliorhinus (represented by \u2020Ps. schwarzhansi and \u2020Ps. reussi) shares tooth root morphologies and vascularization patterns with \u2020Diprosopovenator, gen. nov. We hypothesize that these two sharks form part of an extinct group of carcharhiniforms characterized by a distinct root morphology (viz., low hemiaulacorhize roots with very flat and strongly flared basal faces protruding below the crown labially and mesiodistally and with a well-developed central labiobasal notch). Consequently, we propose a new family of Late Cretaceous carcharhiniforms, \u2020Pseudoscyliorhinidae, fam. nov., to include the new taxon, as well as \u2020Pseudoscyliorhinus. \u2020Pseudoscyliorhinidae, fam. nov., shows a wide European distribution during the Late Cretaceous, ranging from the early Cenomanian to the late Campanian. The longevity of Scyliorhinidae, with a fossil record extending back into the Middle Jurassic, however, remains ambiguous and unresolved; therefore, it may be best to regard the assignment of fossil taxa to Scyliorhinidae as currently uncertain pending further taxonomic work.", "keyphrases": ["new genus", "extinct ground shark", "\u2020pseudoscyliorhinidae"]}
{"id": "paleo.010179", "title": "A New Sauropodomorph Dinosaur from the Early Jurassic of Patagonia and the Origin and Evolution of the Sauropod-type Sacrum", "abstract": "Background The origin of sauropod dinosaurs is one of the major landmarks of dinosaur evolution but is still poorly understood. This drastic transformation involved major skeletal modifications, including a shift from the small and gracile condition of primitive sauropodomorphs to the gigantic and quadrupedal condition of sauropods. Recent findings in the Late Triassic\u2013Early Jurassic of Gondwana provide critical evidence to understand the origin and early evolution of sauropods. Methodology/Principal Findings A new sauropodomorph dinosaur, Leonerasaurus taquetrensis gen. et sp. nov., is described from the Las Leoneras Formation of Central Patagonia (Argentina). The new taxon is diagnosed by the presence of anterior unserrated teeth with a low spoon-shaped crown, amphicoelous and acamerate vertebral centra, four sacral vertebrae, and humeral deltopectoral crest low and medially deflected along its distal half. The phylogenetic analysis depicts Leonerasaurus as one of the closest outgroups of Sauropoda, being the sister taxon of a clade of large bodied taxa composed of Melanorosaurus and Sauropoda. Conclusions/Significance The dental and postcranial anatomy of Leonerasaurus supports its close affinities with basal sauropods. Despite the small size and plesiomorphic skeletal anatomy of Leonerasaurus, the four vertebrae that compose its sacrum resemble that of the large-bodied primitive sauropods. This shows that the appearance of the sauropod-type of sacrum predated the marked increase in body size that characterizes the origins of sauropods, rejecting a causal explanation and evolutionary linkage between this sacral configuration and body size. Alternative phylogenetic placements of Leonerasaurus as a basal anchisaurian imply a convergent acquisition of the sauropod-type sacrum in the new small-bodied taxon, also rejecting an evolutionary dependence of sacral configuration and body size in sauropodomorphs. This and other recent discoveries are showing that the characteristic sauropod body plan evolved gradually, with a step-wise pattern of character appearance.", "keyphrases": ["new sauropodomorph dinosaur", "jurassic", "sauropod-type sacrum"]}
{"id": "paleo.002370", "title": "Taphonomic experiments resolve controls on the preservation of melanosomes and keratinous tissues in feathers", "abstract": "Fossils are a key source of data on the evolution of feather structure and function through deep time, but their ability to resolve macroevolutionary questions is compromised by an incomplete understanding of their taphonomy. Critically, the relative preservation potential of two key feather components, melanosomes and keratinous tissue, is not fully resolved. Recent studies suggesting that melanosomes are preferentially preserved conflict with observations that melanosomes preserve in fossil feathers as external moulds in an organic matrix. To date, there is no model to explain the latter mode of melanosome preservation. We addressed these issues by degrading feathers in systematic taphonomic experiments incorporating decay, maturation and oxidation in isolation and combination. Our results reveal that the production of mouldic melanosomes requires interactions with an oxidant and is most likely to occur prior to substantial maturation. This constrains the taphonomic conditions under which melanosomes are likely to be fossilized. Critically, our experiments also confirm that keratinous feather structures have a higher preservation potential than melanosomes under a range of diagenetic conditions, supporting hitherto controversial hypotheses that fossil feathers can retain degraded keratinous structures.", "keyphrases": ["experiment", "melanosome", "feather", "mould", "oxidant"]}
{"id": "10.1017/pab.2018.8", "title": "Body-shape diversity in Triassic\u2013Early Cretaceous neopterygian fishes: sustained holostean disparity and predominantly gradual increases in teleost phenotypic variety", "abstract": "Abstract. Comprising Holostei and Teleostei, the \u223c 32,000 species of neopterygian fishes are anatomically disparate and represent the dominant group of aquatic vertebrates today. However, the pattern by which teleosts rose to represent almost all of this diversity, while their holostean sister-group dwindled to eight extant species and two broad morphologies, is poorly constrained. A geometric morphometric approach was taken to generate a morphospace from more than 400 fossil taxa, representing almost all articulated neopterygian taxa known from the first 150 million years\u2014roughly 60%\u2014of their history (Triassic-Early Cretaceous). Patterns of morphospace occupancy and disparity are examined to: (1) assess evidence for a phenotypically \u201cdominant\u201d holostean phase; (2) evaluate whether expansions in teleost phenotypic variety are predominantly abrupt or gradual, including assessment of whether early apomorphy-defined teleosts are as morphologically conservative as typically assumed; and (3) compare diversification in crown and stem teleosts. The systematic affinities of dapediiforms and pycnodontiforms, two extinct neopterygian clades of uncertain phylogenetic placement, significantly impact patterns ofmorphological diversification. For instance, alternative placements dictate whether or not holosteans possessed statistically higher disparity than teleosts in the Late Triassic and Jurassic. Despite this ambiguity, all scenarios agree that holosteans do not exhibit a decline in disparity during the Early Triassic\u2013Early Cretaceous interval, but insteadmaintain their Toarcian\u2013Callovian variety until the end of the Early Cretaceouswithout substantial further expansions.After a conservative Induan\u2013Carnian phase, teleosts colonize (and persistently occupy) novel regions of morphospace in a predominantly gradual manner until the Hauterivian, after which expansions are rare. Furthermore, apomorphy-defined teleosts possess greater phenotypic variety than typically assumed. Comparison of crown and stem teleost partial disparity indicates that, despite a statistically significant increase in crown teleost disparity between the Late Jurassic and earliest Cretaceous, stem teleosts remained important long-term contributors to overall teleost disparity during this time.", "keyphrases": ["neopterygian fish", "teleost", "phenotypic variety"]}
{"id": "10.1666/0094-8373-35.4.525", "title": "Komodo monitor (Varanus komodoensis) feeding behavior and dental function reflected through tooth marks on bone surfaces, and the application to ziphodont paleobiology", "abstract": "Abstract Most functional interpretations of ziphodont dentition are based on limited morphometric, behavioral, and taphonomic studies, but few are based on controlled observations of a modern ziphodont consumer. The purpose of this study is to determine through controlled feeding observations if the behaviors indicative of a ziphodont consumer are reflected by tooth marks left on bone surfaces by Varanus komodoensis, the Komodo monitor. We document feeding behavior, expand upon dental function, and correlate these aspects with tooth mark production. We also discuss the significance and limits of applying these data to fossil assemblages. Goat carcasses were fed to 11 captive individuals. V. komodoensis modifies bone surfaces extensively. Individuals exhibit a \u201cmedial-caudal arc\u201d when defleshing, followed by inertial swallowing. Bone crushing was not observed. The vast majority of tooth marks are scores, with pits being significantly less common. Tooth furrows and punctures are rare. \u201cEdge marks\u201d are produced on flat elements. Marks are elongate and narrow, with variable lengths and curvature. Over one-third of the marks occur within parallel clusters. Striations are evident on 5% of all marks. Both feeding behavior and tooth marks indicate that ziphodont crowns are ideal for defleshing by being drawn distally through a carcass. Crowns are poorly built for crushing, and within-bone nutrients are acquired through swallowing. Mark production is a by-product of the distal crown movement during the flesh removal process. Scores are the consequence of apical dragging. Edge marks and striated scores result respectively from distal and mesial carinae contact. Mark curvature is the consequence of arcing motions. Parallel clusters may result from repetitive defleshing strokes and/or from multiple crown contacts during a stroke. These observations can be used to draw functional, behavioral, and taphonomic interpretations from fossil assemblages. When they are provisionally applied to theropod tooth marks, similar crown function and defleshing behavior with little bone crushing is apparent. Differences occur concerning mark frequency and curvature, relating potentially to taphonomic biases and rostral motion, respectively.", "keyphrases": ["varanus komodoensis", "tooth mark", "bone surface", "dentition", "carcass"]}
{"id": "paleo.004156", "title": "Morphology of the oldest fossil subfamily of Limoniidae (Diptera, Architipulinae) in the light of exceptionally preserved Mesozoic material", "abstract": "Based on known fossil evidence the extinct subfamily Architipulinae is considered to be the oldest evolutionary group of the Limoniidae, the largest family within the infraorder Tipulomorpha. The morphology of this subfamily, which includes 11 genera, has so far been based mainly on wing venation. New well-preserved representatives of the genus Cretolimonia Kalugina, 1986 were recovered from the Jurassic/Cretaceous boundary of Shevia and Daya, Transbaikalia, as well as from mid-Cretaceous amber from Kachin, Myanmar. This new material enriches our knowledge of the subfamily Architipulinae and of the genus Cretolimonia, and allows us to ascertain the detailed morphological structure of the female copulatory apparatus with spermathecae and the structure of the male hypopygium. The combination of detailed impression fossils with a specimen preserved three-dimensionally in resin has permitted study of the morphology of this Mesozoic fly genus almost to the level of modern genera. The paper includes descriptions of four new species of Cretolimonia: C. lukashevichae sp. nov., C. pseudojurassica sp. nov., C. dayana sp. nov. from sedimentary rocks, and C. mikolajczyki sp. nov. from Myanmar amber, supported with a key to all known species.\nThe Limoniidae (limoniid craneflies), with over 10,000 described extant species, is the largest family in the dipteran infraorder Tipulomorpha, and one of the largest among all Nematocera. It is currently divided into seven subfamilies, three of which are extinct (Architipulinae, Eotipulinae, Drinosinae), and four extant: Limnophilinae, Chioneinae, Dactylolabinae, and Limoniinae (Fig. 1 ). Based on the fossil data known to date Architipulinae is considered the oldest group of Limoniidae 1-7 , with the oldest representative Architipula youngi Krzemi\u0144ski, 1992 dating from the Late Triassic of North America 3 . This species was used to calibrate the age of the Tipulomorpha clade in the phylogenetic tree of Diptera 8 . During the Jurassic, the family Limoniidae, including Architipulinae, underwent rapid radiation expressed in an abundant and diverse assemblage of genera and species 3,7,9-16 . In the Cretaceous, Architipulinae gradually became extinct, while other limoniid families had appeared in that time.\nThe subfamily Architipulinae includes 11 fossil genera:", "keyphrases": ["diptera", "architipulinae", "late triassic", "morphology", "old group"]}
{"id": "paleo.000901", "title": "Tropical sea surface temperatures for the past four centuries reconstructed from coral archives", "abstract": "Most annually resolved climate reconstructions of the Common Era are based on terrestrial data, making it a challenge to independently assess how recent climate changes have affected the oceans. Here as part of the Past Global Changes Ocean2K project, we present four regionally calibrated and validated reconstructions of sea surface temperatures in the tropics, based on 57 published and publicly archived marine paleoclimate data sets derived exclusively from tropical coral archives. Validation exercises suggest that our reconstructions are interpretable for much of the past 400 years, depending on the availability of paleoclimate data within, and the reconstruction validation statistics for, each target region. Analysis of the trends in the data suggests that the Indian, western Pacific, and western Atlantic Ocean regions were cooling until modern warming began around the 1830s. The early 1800s were an exceptionally cool period in the Indo-Pacific region, likely due to multiple large tropical volcanic eruptions occurring in the early nineteenth century. Decadal-scale variability is a quasi-persistent feature of all basins. Twentieth century warming associated with greenhouse gas emissions is apparent in the Indian, West Pacific, and western Atlantic Oceans, but we find no evidence that either natural or anthropogenic forcings have altered El Nino\u2013Southern Oscillation-related variance in tropical sea surface temperatures. Our marine-based regional paleoclimate reconstructions serve as benchmarks against which terrestrial reconstructions as well as climate model simulations can be compared and as a basis for studying the processes by which the tropical oceans mediate climate variability and change.", "keyphrases": ["sea surface temperature", "century", "coral archive"]}
{"id": "10.1080/03115518.2017.1296189", "title": "The age of the Takatika Grit, Chatham Islands, New Zealand", "abstract": "Hollis, C.J, Stickley, C.E., Bijl, P.K., Schi\u00f8ler, P., Clowes, C.D., Li, X, Campbell, H. March 2017. The age of the Takatika Grit, Chatham Islands, New Zealand. Alcheringa 41, xxx\u2013xxx. ISSN 0311-5518. The oldest Paleogene strata on Chatham Islands, east of New Zealand, are the phosphatized conglomerates and sandstones of the Takatika Grit that crops out on the northeastern coast at Tioriori and unconformably overlies the Chatham Schist. An intact Cretaceous\u2013Paleogene boundary transition is not preserved at this locality. New biostratigraphic analysis of dinoflagellate, diatom and radiolarian microfossil assemblages confirms that the Takatika Grit is of late early\u2013middle Paleocene (New Zealand Teurian stage) age but contains reworked microfossils of early Campanian (Early Haumurian) age. Vertebrate fossils found in this unit are inferred to be a mixture of reworked Cretaceous and in situ Paleocene bones and teeth. The overlying Tutuiri Greensand is of middle\u2013late Paleocene age in its lower part and also contains reworked Cretaceous microfossils. Christopher J. Hollis [c.hollis@gns.cri.nz], Chris Clowes [c.clowes@gns.cri.nz], Xun Li [x.li@gns.cri.nz], Hamish Campbell [h.campbell@gns.cri.nz], GNS Science, PO Box 30-368, Lower Hutt 5040, New Zealand; Catherine Stickley, Evolution Applied Limited, 50 Mitchell Way, Upper Rissington, Cheltenham GL54 2PL, UK [catherine.stickley@gmail.com]; Peter Bijl [p.k.bijl@uu.nl], Marine Palynology and Paleoceanography, Department of Earth Sciences, Utrecht University, 3584 CS Utrecht, the Netherlands; Poul Schi\u00f8ler [poul.schioler@mgpalaeo.com.au], Morgan Goodall Palaeo, Unit 1/5 Arvida St, Malaga, WA 6090, Australia.", "keyphrases": ["takatika grit", "chatham islands", "new zealand"]}
{"id": "10.1080/02724634.2018.1451872", "title": "The Postcranial Anatomy of Diademodon tetragonus (Cynodontia, Cynognathia)", "abstract": "ABSTRACT \n A survey of the postcranial anatomy of a specimen of Diademodon tetragonus recovered from the Upper Omingonde Formation in Namibia resulted in the recognition of diagnostic characters in the axis, scapula, interclavicle, manubrium, sternebrae, humerus, ilium, ischium, and femur. Our comparative analysis shows that these and other postcranial features distinguish Diademodon tetragonus from other cynognathians. The presence of ossified sternal elements (manubrium and sternebrae) in Diademodon tetragonus stands out because they are otherwise only present in tritylodontids among nonmammaliaform cynodonts. It is suggested that this feature is not linked to body size but could be phylogenetically informative. A review of the postcranial anatomy of specimens previously identified as Diademodon and ?Cynognathus/ ?Diademodon shows that only a few of them can be assigned to Diademodon tetragonus.", "keyphrases": ["postcranial anatomy", "diademodon tetragonus", "cynodontia"]}
{"id": "10.7717/peerj.8453", "title": "Exploring abnormal Cambrian-aged trilobites in the Smithsonian collection", "abstract": "Biomineralised trilobite exoskeletons provide a 250 million year record of abnormalities in one of the most diverse arthropod groups in history. One type of abnormality\u2014repaired injuries\u2014have allowed palaeobiologists to document records of Paleozoic predation, accidental damage, and complications in moulting experienced by the group. Although Cambrian trilobite injuries are fairly well documented, the illustration of new injured specimens will produce a more complete understanding of Cambrian prey items. To align with this perspective, nine new abnormal specimens displaying healed injuries from the Smithsonian National Museum of Natural History collection are documented. The injury pattern conforms to the suggestion of lateralised prey defence or predator preference, but it is highlighted that the root cause for such patterns is obscured by the lumping of data across different palaeoecological and environmental conditions. Further studies of Cambrian trilobites with injuries represent a key direction for uncovering evidence for the Cambrian escalation event.", "keyphrases": ["trilobite", "exoskeleton", "predation", "injury", "abnormal specimen"]}
{"id": "paleo.006395", "title": "End-Cretaceous extinction in Antarctica linked to both Deccan volcanism and meteorite impact via climate change", "abstract": "The cause of the end-Cretaceous (KPg) mass extinction is still debated due to difficulty separating the influences of two closely timed potential causal events: eruption of the Deccan Traps volcanic province and impact of the Chicxulub meteorite. Here we combine published extinction patterns with a new clumped isotope temperature record from a hiatus-free, expanded KPg boundary section from Seymour Island, Antarctica. We document a 7.8\u00b13.3 \u00b0C warming synchronous with the onset of Deccan Traps volcanism and a second, smaller warming at the time of meteorite impact. Local warming may have been amplified due to simultaneous disappearance of continental or sea ice. Intra-shell variability indicates a possible reduction in seasonality after Deccan eruptions began, continuing through the meteorite event. Species extinction at Seymour Island occurred in two pulses that coincide with the two observed warming events, directly linking the end-Cretaceous extinction at this site to both volcanic and meteorite events via climate change.", "keyphrases": ["meteorite impact", "climate change", "end-cretaceous extinction"]}
{"id": "paleo.005741", "title": "THE MIDDLE MIOCENE (LAVENTAN) QUEBRADA HONDA FAUNA, SOUTHERN BOLIVIA and A DESCRIPTION OF ITS NOTOUNGULATES", "abstract": "Abstract:\u2002 The Laventan Quebrada Honda Fauna of southern Bolivia is one of the best sampled middle Miocene South American faunas. The present study describes the toxodontid, interatheriid and mesotheriid notoungulates from Quebrada Honda and summarizes the present state of knowledge of the fauna. Toxodontid specimens from Quebrada Honda include two isolated molars, one upper and one lower. The upper molar compares favourably with Paratrigodon and may represent a new species, but too little material is known to make an adequate diagnosis. The lower molar may pertain to the same taxon, or to a distinct species that is even more poorly represented. A new species of the interatheriid Miocochilius is described, M. federicoi, on the basis of a partial skull. It differs from M. anomopodus in its significantly smaller size (at least 20 per cent smaller based on linear upper molar dimensions); relatively wider P4 with deeper lingual sulcus; more prominent middle lobes on upper molars; and M3 with deeper lingual sulcus and more prominent metastyle (distal lobe). The generic allocation of this new species is considered tentative, pending a better understanding of the phylogenetic relationships among currently recognized species of Miocochilius and Protypotherium. Mesotheriids are represented at Quebrada Honda by a pair of poorly preserved mandibles that are referred to Plesiotypotherium minor, a species previously recorded from slightly older deposits near Cerdas, Bolivia. A newly revised faunal list for Quebrada Honda is compiled that includes 30 species of non\u2010volant mammals, 27 of which have been identified to at least genus level. This revised faunal list is used to compare Quebrada Honda to other well\u2010sampled middle\u2013late Miocene faunas (including La Venta, Columbia; Coll\u00f3n\u2010Cur\u00e1, Argentina; and Arroyo Chasic\u00f3, Argentina) using the Simpson Index of faunal similarity. In order to compensate for inadequately identified specimens (i.e. those not identified to genus level), minimum and maximum values of faunal similarly were estimated using two different sets of assumptions. The analysis indicates that the middle\u2010latitude Quebrada Honda Fauna is more similar to the slightly older high\u2010latitude fauna of Coll\u00f3n\u2010Cur\u00e1 than to the contemporaneous low\u2010latitude fauna of La Venta, suggesting that isolating mechanisms between the low and middle latitudes were in place during the early and/or middle Miocene. The relative paucity of taxa shared between Quebrada Honda and La Venta, despite their contemporaneity, suggests that the system of South American Land Mammal \u2018Ages\u2019 (SALMAs) may not be useful for biocorrelation between low\u2010latitude faunas and those from elsewhere in South America.", "keyphrases": ["middle miocene", "quebrada honda fauna", "southern bolivia"]}
{"id": "paleo.011601", "title": "Earliest Example of a Giant Monitor Lizard (Varanus, Varanidae, Squamata)", "abstract": "Background Varanidae is a clade of tiny (<20 mm pre-caudal length [PCL]) to giant (>600 mm PCL) lizards first appearing in the Cretaceous. True monitor lizards (Varanus) are known from diagnostic remains beginning in the early Miocene (Varanus rusingensis), although extremely fragmentary remains have been suggested as indicating earlier Varanus. The paleobiogeographic history of Varanus and timing for origin of its gigantism remain uncertain. Methodology/Principal Findings A new Varanus from the Mytilini Formation (Turolian, Miocene) of Samos, Greece is described. The holotype consists of a partial skull roof, right side of a braincase, partial posterior mandible, fragment of clavicle, and parts of six vertebrae. A cladistic analysis including 83 taxa coded for 5733 molecular and 489 morphological characters (71 previously unincluded) demonstrates that the new fossil is a nested member of an otherwise exclusively East Asian Varanus clade. The new species is the earliest-known giant (>600 mm PCL) terrestrial lizard. Importantly, this species co-existed with a diverse continental mammalian fauna. Conclusions/Significance The new monitor is larger (longer) than 99% of known fossil and living lizards. Varanus includes, by far, the largest limbed squamates today. The only extant non-snake squamates that approach monitors in maximum size are the glass-snake Pseudopus and the worm-lizard Amphisbaena. Mosasauroids were larger, but exclusively marine, and occurred only during the Late Cretaceous. Large, extant, non-Varanus, lizards are limbless and/or largely isolated from mammalian competitors. By contrast, our new Varanus achieved gigantism in a continental environment populated by diverse eutherian mammal competitors.", "keyphrases": ["varanus", "greece", "vertebrae"]}
{"id": "10.1002/jmor.20975", "title": "Do sharks exhibit heterodonty by tooth position and over ontogeny? A comparison using elliptic Fourier analysis", "abstract": "Tooth morphology is often used to inform the feeding ecology of an organism as these structures are important to procure and process dietary resources. In sharks, differences in morphology may facilitate the capture and handling of prey with different physical properties. However, few studies have investigated differences in tooth morphology over ontogeny, throughout the jaws of a single species, or among species at multiple tooth positions. Bull (Carcharhinus leucas), blacktip (Carcharhinus limbatus), and bonnethead sharks (Sphyrna tiburo) are coastal predators that exhibit ontogenetic dietary shifts, but differ in their feeding ecologies. This study measured tooth morphology at six positions along the upper and lower jaws of each species using elliptic Fourier analysis to make comparisons within and among species over their ontogeny. Significant ontogenetic differences were detected at four of the six tooth positions in bull sharks, but only the posterior position on the lower jaw appeared to exhibit a functionally relevant shift in morphology. No ontogenetic changes in morphology were detected in blacktip or bonnethead sharks. Intraspecific comparisons found that most tooth positions significantly differed from one another across all species, but heterodonty was greatest in bull sharks. Additionally, interspecific comparisons found differences among all species at each tooth position except between bull and blacktip sharks at two positions. These morphological patterns within and among species may have implications for prey handling efficiency, as well as in providing insight for paleoichthyology studies and reevaluating heterodonty in sharks.", "keyphrases": ["heterodonty", "tooth position", "ontogeny", "fourier analysis", "dietary shift"]}
{"id": "paleo.012848", "title": "Lucy's Flat Feet: The Relationship between the Ankle and Rearfoot Arching in Early Hominins", "abstract": "Background In the Plio-Pleistocene, the hominin foot evolved from a grasping appendage to a stiff, propulsive lever. Central to this transition was the development of the longitudinal arch, a structure that helps store elastic energy and stiffen the foot during bipedal locomotion. Direct evidence for arch evolution, however, has been somewhat elusive given the failure of soft-tissue to fossilize. Paleoanthropologists have relied on footprints and bony correlates of arch development, though little consensus has emerged as to when the arch evolved. Methodology/Principal Findings Here, we present evidence from radiographs of modern humans (n\u200a=\u200a261) that the set of the distal tibia in the sagittal plane, henceforth referred to as the tibial arch angle, is related to rearfoot arching. Non-human primates have a posteriorly directed tibial arch angle, while most humans have an anteriorly directed tibial arch angle. Those humans with a posteriorly directed tibial arch angle (8%) have significantly lower talocalcaneal and talar declination angles, both measures of an asymptomatic flatfoot. Application of these results to the hominin fossil record reveals that a well developed rearfoot arch had evolved in Australopithecus afarensis. However, as in humans today, Australopithecus populations exhibited individual variation in foot morphology and arch development, and \u201cLucy\u201d (A.L. 288-1), a 3.18 Myr-old female Australopithecus, likely possessed asymptomatic flat feet. Additional distal tibiae from the Plio-Pleistocene show variation in tibial arch angles, including two early Homo tibiae that also have slightly posteriorly directed tibial arch angles. Conclusions/Significance This study finds that the rearfoot arch was present in the genus Australopithecus. However, the female Australopithecus afarensis \u201cLucy\u201d has an ankle morphology consistent with non-pathological flat-footedness. This study suggests that, as in humans today, there was variation in arch development in Plio-Pleistocene hominins.", "keyphrases": ["foot", "distal tibiae", "tibial arch angle", "australopithecus", "lucy"]}
{"id": "paleo.009151", "title": "A New Saurichthyiform (Actinopterygii) with a Crushing Feeding Mechanism from the Middle Triassic of Guizhou (China)", "abstract": "Background Equipped with an effective predatory feeding mechanism enhanced by large and sharp teeth, pointed snout and elongate body, saurichthyiform fishes are considered common fish-eaters in the early Mesozoic aquatic ecosystems. Additionally, because of the similar body plan across species, saurichthyiforms are also regarded evolutionally conservative, with few morphological and ecological changes during their long history. However, their phylogenetic affinity remains unclear as to whether they are chondrostean, neopterygian or stem-actinopteran, and likewise the intrarelationships of the group have rarely been explored. Methodology/Principal Findings Here we report a new saurichthyiform from the Middle Triassic of Guizhou, China, based on the well-preserved specimens including a 3-D braincase. The new taxon, Yelangichthys macrocephalus gen. et sp. nov., is unique among saurichthyiforms in having a peculiar neurocranium with a broad orbital tectum, paired posterior myodomes, a deep, transverse fossa in the posterodorsal part of the orbit, and a feeding mechanism structured for durophagy. Phylogenetic analysis places Yelangichthys gen. nov. at the most basal position in the Saurichthyiformes as the sister to Saurichthyidae, and a new family Yelangichthyidae is erected to include only Y. macrocephalus gen. et sp. nov. The monophyly of the Chondrostei comprising [Saurichthyiformes + Acipenseriformes] Birgeriiformes is supported, but not the monophyly of Saurichthys, the type genus of Saurichthyidae. With its outstanding osteological details, Yelangichthys gen. nov. greatly increases the neurocranial variations in saurichthyiforms, and its novel feeding structure suggests the consumption of hard-preys instead of fishes. Conclusions/Significance Our findings highlight the detailed osteology of a saurichthyiform braincase and its feeding design. We suggest that saurichthyiforms are closely allied to the Acipenseriformes. Saurichthyiforms were very diverse in the cranial osteology and they might have undergone a rapid evolutionary radiation via, for the new material here, transforming the feeding mechanism and thus exploiting the food resources unsuitable for other saurichthyiforms.", "keyphrases": ["new saurichthyiform", "feeding mechanism", "middle triassic", "phylogenetic analysis"]}
{"id": "10.5194/cp-13-1695-2017", "title": "Simulation of climate, ice sheets and CO 2 evolution during the last four glacial cycles with an Earth system model of intermediate complexity", "abstract": "Abstract. In spite of significant progress in paleoclimate reconstructions and modelling of different aspects of the past glacial cycles, the mechanisms which transform regional and seasonal variations in solar insolation into long-term and global-scale glacial\u2013interglacial cycles are still not fully understood \u2013 in particular, in relation to CO2 variability. Here using the Earth system model of intermediate complexity CLIMBER-2 we performed simulations of the co-evolution of climate, ice sheets, and carbon cycle over the last 400\u202f000\u00a0years using the orbital forcing as the only external forcing. The model simulates temporal dynamics of CO2, global ice volume, and other climate system characteristics in good agreement with paleoclimate reconstructions. These results provide strong support for the idea that long and strongly asymmetric glacial cycles of the late Quaternary represent a direct but strongly nonlinear response of the Northern Hemisphere ice sheets to orbital forcing. This response is strongly amplified and globalised by the carbon cycle feedbacks. Using simulations performed with the model in different configurations, we also analyse the role of individual processes and sensitivity to the choice of model parameters. While many features of simulated glacial cycles are rather robust, some details of CO2 evolution, especially during glacial terminations, are sensitive to the choice of model parameters. Specifically, we found two major regimes of CO2 changes during terminations: in the first one, when the recovery of the Atlantic meridional overturning circulation\u00a0(AMOC) occurs only at the end of the termination, a pronounced overshoot in CO2 concentration occurs at the beginning of the interglacial and CO2 remains almost constant during the interglacial or even declines towards the end, resembling Eemian CO2 dynamics. However, if the recovery of the AMOC occurs in the middle of the glacial termination, CO2 concentration continues to rise during the interglacial, similar to the Holocene. We also discuss the potential contribution of the brine rejection mechanism for the CO2 and carbon isotopes in the atmosphere and the ocean during the past glacial termination.", "keyphrases": ["ice sheet", "glacial cycle", "earth system model"]}
{"id": "paleo.007879", "title": "A crown\u2010group demosponge from the early Cambrian Sirius Passet Biota, North Greenland", "abstract": "Calibration of the divergence times of sponge lineages and understanding of their phylogenetic history are hampered by the difficulty in recognizing crown versus stem groups in the fossil record. A new specimen from the lower Cambrian (Series 2, Stage 3; approximately 515 Ma) Sirius Passet Biota of North Greenland has yielded a diagnostic spicule assemblage of the extant demosponge lineages Haploscleromorpha and/or Heteroscleromorpha. The specimen has disarticulated approximately in situ, but represents an individual sponge that possessed monaxon spicules combined with a range of slightly smaller sigma, toxa and unique spiral morphologies. The combination of spicule forms, together with their relatively large size, suggests that the sponge represents the stem lineage of Haploscleromorpha + Heteroscleromorpha. This is the first crown\u2010group demosponge described from the early Cambrian and provides the most reliable calibration point currently available for phylogenetic studies.", "keyphrases": ["crown\u2010group demosponge", "sirius passet biota", "north greenland"]}
{"id": "10.1080/14772019.2019.1662500", "title": "Proterotheriids and macraucheniids (Litopterna: Mammalia) from the Pampa Castillo Fauna, Chile (early Miocene, Santacrucian SALMA) and a new phylogeny of Proterotheriidae", "abstract": "Here we describe the litopterns, a diverse and temporally long-ranging clade of South American native \u2018ungulates\u2019, of the early Miocene Pampa Castillo fauna from the Galera Formation in the Andean Cordillera of southern Chile, and present a new phylogeny of Proterotheriidae, the most speciose litoptern subgroup. Two proterotheriids occur at Pampa Castillo: Thoatherium, the northernmost and first record of this taxon outside Santa Cruz Province, Argentina, and Picturotherium, known previously solely from the Pinturas Formation of north-western Santa Cruz Province. Macraucheniidae are represented at Pampa Castillo by Theosodon. Collectively, these three taxa suggest an early Miocene (Santacrucian South American Land Mammal \u2018Age\u2019 (SALMA)) age for the fossil mammal fauna from Pampa Castillo, reinforcing previous biochronological interpretations. Results of a comprehensive phylogenetic analysis identify Megadolodus molariformis as the earliest-diverging member of Proterotheriidae, a name for which we propose a stem-based definition. Few multi-species proterotheriid genera were recovered as monophyletic in our analysis. Three \u2018anisolambdid\u2019 litopterns, initially assumed to represent outgroups, instead nest deeply within Proterotheriidae, implying long ghost lineages. The phylogenetic placement of the four proterotheriids from the middle Miocene La Venta fauna of Colombia sheds light on the poorly understood long-term isolation of tropical faunas and their degree of exchange with high-latitude regions. Santacrucian SALMA assemblages in Patagonia are notable in that older localities preferentially produce earlier-diverging proterotheriids. Older sites are also marked by a mix of brachyodont and hypsodont taxa, whereas younger sites yield strictly hypsodont forms, supporting the notion of increasing aridity in Patagonia through this interval. Proterotheriids alone cannot be used to discriminate between an early or late Santacrucian age for the Pampa Castillo fauna, but the brachyodonty of Picturotherium suggests a humid climate and closed habitats.", "keyphrases": ["litopterna", "pampa castillo fauna", "proterotheriidae"]}
{"id": "10.2110/palo.2007.p07-020r", "title": "Three-dimensional Morphology of the Ichnofossil Phycosiphon incertum and Its Implication for Paleoslope Inclination", "abstract": "Abstract Details of the three-dimensional morphology of the ichnofossil Phycosiphon incertum collected from deposits on submarine slopes are reconstructed by processing a series of images obtained from polished sections of the samples. Samples were collected from the mudstone around a slump scar in the Paleocene Shiomi Formation, northern Japan, which is characterized by the occurrence of slump scars. The reconstructed morphology of Phycosiphon incertum is a meandering tube with a flattened ellipse cross section. The tubes are flattened in a plane oblique to the bedding surfaces and aligned along the same direction at both the interior and exterior of the slump scar. Flattening of the tubes was likely caused by sediment compaction, and the tube flattens toward the horizontal plane that is oblique to the bedding plane because of the paleoslope inclination. The difference between the bedding and flattening planes of the tubes of Phycosiphon incertum may imply paleoslope inclination. When the inclination of the bedding plane of the Shiomi Formation is corrected using the flattened surfaces, the bedding plane dips by 9\u00b0 toward the southeast, which conforms to the paleocurrent direction of the turbidites. The morphology of Phycosiphon incertum can, therefore, be used as a paleoslope indicator.", "keyphrases": ["ichnofossil phycosiphon incertum", "paleoslope inclination", "three-dimensional morphology"]}
{"id": "paleo.008917", "title": "Triassic: the crucial period of post-Palaeozoic crinoid diversification", "abstract": "After their near-extinction around the end of the Permian, crinoids recovered during the Triassic and reoccupied almost all ecological niches they had held in Palaeozoic times. Triassic crinoids comprise 33 genera in 12 well-defined families and 5 orders of the subclass Articulata; the systematic position of 4 additional families is unknown. The highest diversity was before the Mid Carnian Wet Intermezzo that caused the extinction of the order Encrinida. Major morphologic changes were connected with the adaptation to various benthic habitats and to pseudoplanktonic and eleutherozoic modes of life. Convergently, the cups of Encrinida and Holocrinida-Isocrinida became cryptodicyclic with large muscular radial facets, arm numbers increased from 5 to more than 300, and the arms of Encrinida became gradually biserial. The Encrinida remained permanently fixed to hardgrounds and acted as frame builders in bioherms. By encrusting bivalve mudstickers some dadocrinids also became secondary soft bottom dwellers. The holocrinid stem evolved preformed rupture points at the lower nodal facets, allowing these crinoids to attach intermittently by cirri. The pseudoplanktonic traumatocrinids evolved extremely long, flexible stems with multiple pore systems and terminal root cirri. Paracomatulids and eocomatulids reduced their stems and adapted to an eleutherozoic mode of life. Somphocrinids miniaturized and remodeled their skeleton towards lightweight construction and adapted to a planktonic life style. After the Triassic no fundamentally novel adaptation was added. Crinoidal limestones, as common in the Palaeozoic, had their last appearance in Middle Triassic times.", "keyphrases": ["diversification", "near-extinction", "ecological niche", "palaeozoic", "triassic"]}
{"id": "10.1017/S0094837300009982", "title": "Experimental disintegration of regular echinoids: roles of temperature, oxygen, and decay thresholds", "abstract": "Laboratory experiments on regular echinoids indicate that low water temperatures retard organic decomposition far more effectively than anoxia, and that the primary role of anoxia in the preservation of articulated multi-element calcareous skeletons may be in excluding scavenging organisms. When tumbled at 20 rpm, specimens that were first allowed to decay for two days in warm seawater (30\u00b0C) disintegrated more than six times faster than specimens treated at room temperature (23\u00b0C) and more than an order of magnitude faster than specimens treated in cool water (11\u00b0C). In contrast, the effects of aerobic versus anerobic decay on disintegration rates were insignificant. The longer the period that specimens were allowed to decay before tumbling, the greater the rate at which specimens disintegrated, until a threshold time that appears to mark the decomposition of collagenous ligaments. This required a few days at 30\u00b0C, about two weeks at 23\u00b0C, and more than 4 weeks at 11\u00b0C for Strongylocentrotus. Up until this threshold, coronas disintegrate by a combination of cross-plate fractures and separation along plate sutures; cross-plate fractures thus can be taphonomic in origin and are not necessarily related to predation. Specimens decayed for longer-than-threshold periods of time disintegrate virtually instantaneously upon tumbling by sutural separation only. Undisturbed coronas can remain intact for months, sufficient time for epibiont occupation. Rates of disintegration were documented semi-quantitatively by recognizing seven stages of test disarticulation, and quantitatively by tensometer measures of test strength and toughness. The effects of temperature and oxygen on decay and the existence of a decay threshold in disintegration should apply at least in a qualitative sense to many other animals whose skeletons consist of multiple, collagen-bound elements. Regular echinoids should still be perceived as taphonomically fragile organisms, but our results suggest the potential for latitudinal as well as bathymetric gradients in the preservation of fossil echinoid faunas. Echinoid preservation under any given set of conditions should also be a function of taxonomic differences in test construction (particularly stereom interlocking along plate sutures) as suggested by previous workers, although our experiments indicate that these effects should only be significant among post-threshold specimens. A survey of regular echinoids from Upper Cretaceous white chalk facies of Britain substantiates the basic experimental patterns, yielding examples of all disarticulation stages and significant taxonomic differences in quality of preservation. A diverse array of borers and encrusters on fossil coronas also corroborates the post-mortem persistence of some tests on mid-latitude seafloors.", "keyphrases": ["disintegration", "regular echinoid", "oxygen"]}
{"id": "paleo.011017", "title": "Repeated evolution of durophagy during ichthyosaur radiation after mass extinction indicated by hidden dentition", "abstract": "Marine tetrapods quickly diversified and were established as marine top predators after the end-Permian Mass extinction (EPME). Ichthyosaurs were the forerunner of this rapid radiation but the main drivers of the diversification are poorly understood. Cartorhynchus lenticarpus is a basal ichthyosauriform with the least degree of aquatic adaptation, holding a key to identifying such a driver. The unique specimen appeared edentulous based on what was exposed but a CT scanning revealed that the species indeed had rounded teeth that are nearly perpendicular to the jaw rami, and thus completely concealed in lateral view. There are three dental rows per jaw ramus, and the root lacks infoldings of the dentine typical of ichthyopterygians. The well-developed and worn molariform dentition with three tooth rows supports the previous inference that the specimen is not of a juvenile. The premaxilla and the corresponding part of the dentary are edentulous. Molariform dentition evolved three to five times independently within Ichthyosauriformes in the Early and Middle Triassic. Convergent exploitation of hard-shelled invertebrates by different subclades of ichthyosauriforms likely fueled the rapid taxonomic diversification of the group after EPME.", "keyphrases": ["mass extinction", "predator", "triassic"]}
{"id": "paleo.012191", "title": "Synchrotron imaging reveals bone healing and remodelling strategies in extinct and extant vertebrates", "abstract": "Current understanding of bone healing and remodelling strategies in vertebrates has traditionally relied on morphological observations through the histological analysis of thin sections. However, chemical analysis may also be used in such interpretations, as different elements are known to be absorbed and used by bone for different physiological purposes such as growth and healing. These chemical signatures are beyond the detection limit of most laboratory-based analytical techniques (e.g. scanning electron microscopy). However, synchrotron rapid scanning\u2013X-ray fluorescence (SRS\u2013XRF) is an elemental mapping technique that uniquely combines high sensitivity (ppm), excellent sample resolution (20\u2013100 \u00b5m) and the ability to scan large specimens (decimetre scale) approximately 3000 times faster than other mapping techniques. Here, we use SRS\u2013XRF combined with microfocus elemental mapping (2\u201320 \u00b5m) to determine the distribution and concentration of trace elements within pathological and normal bone of both extant and extinct archosaurs (Cathartes aura and Allosaurus fragilis). Results reveal discrete chemical inventories within different bone tissue types and preservation modes. Chemical inventories also revealed detail of histological features not observable in thin section, including fine structures within the interface between pathological and normal bone as well as woven texture within pathological tissue.", "keyphrases": ["bone healing", "remodelling strategy", "vertebrate"]}
{"id": "10.1111/PALA.12521", "title": "Taxonomic identification using virtual palaeontology and geometric morphometrics: a case study of Jurassic nerineoidean gastropods", "abstract": "Taxonomic identification of fossils is fundamental to a wide range of geological and biological disciplines. Many fossil groups are identified based on expert judgement, which requires extensive experience and is not always available for the specific taxonomic group at hand. Nerineoideans, a group of extinct gastropods that formed a major component of Mesozoic shallow marine environments, have distinctive internal spiral folds that form the basis for their classification at the genus level. However, their identification is often inconsistent because it is based on a set of selected characters reliant upon individual interpretation. This study shows a non\u2010destructive and quantitative method for their identification using micro\u2010CT and geometric morphometrics. We examined and micro\u2010CT\u2010scanned nerineoidean specimens from five main families that dominated Europe, Arabia and Africa during the Middle\u2013Late Jurassic. Optimal longitudinal slices were selected from the tomographic reconstructions or from images of polished cross\u2010sections compiled from fossil collections, published work and online databases. Internal whorl outlines were represented by 30 evenly distributed sliding semilandmarks and shape variations were studied using the Procrustes\u2010based geometric morphometrics method. Multivariate analysis shows that Ceritellidae and Ptygmatididae are distinct families, whereas Nerinellidae, Eunerineidae and Nerineidae fall within the same shape variance and cannot be distinguished based on internal whorl outlines. The suggested method can be applied to images from various sources as well as to poorly preserved specimens. Our case study demonstrates the importance of quantitatively re\u2010evaluating taxonomy in the fossil record, promoting the future utility of large datasets.", "keyphrases": ["geometric morphometric", "gastropod", "taxonomic identification"]}
{"id": "10.1080/14772019.2018.1551249", "title": "Postcranial remains of Teraterpeton hrynewichorum (Reptilia: Archosauromorpha) and the mosaic evolution of the saurian postcranial skeleton", "abstract": "Teraterpeton hrynewichorum is an unusual archosauromorph reptile from the Upper Triassic (Carnian) Evangeline Member of the Wolfville Formation in Nova Scotia (Canada). Its long snout has transversely broad, cusped \u2018molariform\u2019 teeth posteriorly and lacks teeth anteriorly. The temporal region of the cranium is \u2018euryapsid\u2019 with large upper and closed lower temporal fenestrae. A previously undescribed specimen referable to Teraterpeton includes a nearly complete pelvic girdle and both hind limbs. The ilium has a long, dorsoventrally deep anterior process similar to that of derived rhynchosaurs. The pelvis has a well-developed thyroid fenestra, a feature shared only by Tanystropheidae among Archosauromorpha. Metatarsal V is proximodistally short, resembling the condition in Tanystropheidae. The pedal unguals of Teraterpeton are strongly flattened mediolaterally, dorsoventrally deep and weakly curved, much like the manual unguals. We performed a phylogenetic analysis of a matrix comprising 61 taxa of Permo-Triassic diapsid reptiles and 337 characters, which supports the position of Teraterpeton as the sister-taxon of Trilophosaurus + Spinosuchus. In the current phylogeny, parsimony-based character optimization of the aforementioned character-states in Teraterpeton indicate that all were acquired independently from other saurian lineages. The unusual combination of postcranial features in Teraterpeton underscores the critical importance of comprehensive taxon sampling for understanding the mode of character change among Triassic diapsid reptiles and careful apomorphy-based identifications to faunal analyses.", "keyphrases": ["teraterpeton hrynewichorum", "archosauromorpha", "postcranial skeleton", "upper triassic", "nova scotia"]}
{"id": "paleo.006093", "title": "Morphometry of the teeth of western North American tyrannosaurids and its applicability to quantitative classification", "abstract": "Gross tooth morphology and serration morphology were examined to determine a quantifiable method for classifying tyrannosaurid tooth crowns from western North America. From the examination of teeth in jaws, tyrannosaurid teeth could be qualitatively assigned to one of five types based on the cross-sectional shape of the base of the tooth and characteristics of the mesial carina. A principal component analysis (PCA) revealed that much of the variance in tooth shape was a result of isometry, but some gross morphological variables exhibited strong positive allometry. Non-size associated factors were also important in determining tooth shape, particularly when data on denticle dimensions were considered in the analysis. While PCA identified important factors in variation, PCA ordination plots did not cluster the teeth into distinct, separate groupings based on taxon or bone of origin. The group classification functions determined by discriminant analysis, though not universally successful for classifying unidentified isolated teeth of all tyrannosaurids, do identify bone of origin of adult Albertosaurus, Daspletosaurus, and Gorgosaurus teeth at a statistically acceptable level.", "keyphrases": ["tyrannosaurid", "tooth", "pca", "discriminant analysis"]}
{"id": "10.1080/14772019.2020.1759706", "title": "Osteology of Klamelisaurus gobiensis (Dinosauria, Eusauropoda) and the evolutionary history of Middle\u2013Late Jurassic Chinese sauropods", "abstract": "Fossil-rich deposits from the Middle and Late Jurassic of China have yielded a diverse array of sauropod dinosaurs, including numerous species referred to Mamenchisaurus and Omeisaurus. Despite an abundance of fossils and a proliferation of taxa, the anatomy of Middle\u2013Late Jurassic Chinese sauropods remains poorly documented. Here, we comprehensively redescribe and illustrate Klamelisaurus gobiensis from the Middle\u2013Late Jurassic Shishugou Formation of northwest China. Phylogenetic analyses conducted under parsimony and time-calibrated Bayesian optimality criteria consistently recover Klamelisaurus as a member of a predominantly Chinese radiation of exceptionally long-necked eusauropods that includes Mamenchisaurus spp., Chuanjiesaurus, Qijianglong and Wamweracaudia. In most analyses, this lineage also includes Euhelopus, reviving a \u2018traditional\u2019 Euhelopodidae and calling into question the macronarian affinities of Euhelopus. Klamelisaurus shares several features with Euhelopus that are unique to a subset of East Asian taxa or rare among sauropods, including a convex ventral margin of the prezygodiapophyseal lamina in middle\u2013posterior cervical vertebrae, a ventrally bifurcated postzygodiapophyseal lamina in posterior cervical vertebrae, and development of a rugose projection extending anteriorly from the epipophysis into the spinodiapophyseal fossa in most cervical vertebrae. Anatomical comparisons of the cervical vertebrae of Klamelisaurus to several other sauropodomorphs and insights from myological studies of extant archosaurs strongly suggest that this latter structure, often considered part of an epipophyseal-prezygapophyseal lamina, is an epaxial muscle scar that is distinct from pneumatic structures of the lateral surface of the neural spine. The phylogenetic and comparative anatomical data presented here provide a foundation for future revision of the taxonomy and systematics of sauropods from the Junggar and Sichuan basins.", "keyphrases": ["klamelisaurus gobiensis", "middle\u2013late jurassic", "sauropod", "mamenchisaurus", "phylogenetic analysis"]}
{"id": "paleo.001711", "title": "Long-term persistence of structured habitats: seagrass meadows as enduring hotspots of biodiversity and faunal stability", "abstract": "Ecological studies indicate that structurally complex habitats support elevated biodiversity, stability and resilience. The long-term persistence of structured habitats and their importance in maintaining biodiverse hotspots remain underexplored. We combined geohistorical data (dead mollusc assemblages, \u2018DA\u2019) and contemporary surveys (live mollusc assemblages, \u2018LA\u2019) to assess the persistence of local seagrass habitats over multi-centennial timescales and to evaluate whether they acted as long-term drivers of biodiversity, stability and resilience of associated fauna. We sampled structured seagrass meadows and open sandy bottoms along Florida's Gulf Coast. Results indicated that: (i) LA composition differed significantly between the two habitat types, (ii) LA from seagrass sites were characterized by significantly elevated local biodiversity and significantly higher spatial stability, (iii) DA composition differed significantly between the two habitat types, and (iv) fidelity between LA and DA was significantly greater for seagrass habitats. Contemporary results support the hypotheses that local biodiversity and spatial stability of marine benthos are both elevated in structured seagrass habitats. Geohistorical results suggest that structured habitats persist as local hotspots of elevated biodiversity and faunal stability over centennial-to-millennial timescales; indicating that habitat degradation and concomitant loss within structurally complex marine systems is a key driver of declining biodiversity and resilience.", "keyphrases": ["seagrass meadow", "biodiversity", "long-term persistence"]}
{"id": "10.3133/sir20175109", "title": "Sequence stratigraphy, seismic stratigraphy, and seismic structures of the lower intermediate confining unit and most of the Floridan aquifer system, Broward County, Florida", "abstract": "Deep well injection and disposal of treated wastewater into the highly transmissive saline Boulder Zone in the lower part of the Floridan aquifer system began in 1971. The zone of injection is a highly transmissive hydrogeologic unit, the Boulder Zone, in the lower part of the Floridan aquifer system. Since the 1990s, however, treated wastewater injection into the Boulder Zone in southeastern Florida has been detected at three treated wastewater injection utilities in the brackish upper part of the Floridan aquifer system designated for potential use as drinking water. At a time when usage of the Boulder Zone for treated wastewater disposal is increasing and the utilization of the upper part of the Floridan aquifer system for drinking water is intensifying, there is an urgency to understand the nature of cross-formational fluid flow and identify possible fluid pathways from the lower to upper zones of the Floridan aquifer system. To better understand the hydrogeologic controls on groundwater movement through the Floridan aquifer system in southeastern Florida, the U.S. Geological Survey and the Broward County Environmental Planning and Community Resilience Division conducted a 3.5-year cooperative study from July 2012 to December 2015. The study characterizes the sequence stratigraphy, seismic stratigraphy, and seismic structures of the lower part of the intermediate confining unit aquifer and most of the Floridan aquifer system. Data obtained to meet the study objective include 80 miles of high-resolution, two-dimensional (2D), seismic-reflection profiles acquired from canals in eastern Broward County. These profiles have been used to characterize the sequence stratigraphy, seismic stratigraphy, and seismic structures in a 425-square-mile study area. Horizon mapping of the seismic-reflection profiles and additional data collection from well logs and cores or cuttings from 44 wells were focused on construction of three-dimensional (3D) visualizations of eight sequence stratigraphic cycles that compose the Eocene to Miocene Oldsmar, Avon Park, and Arcadia Formations. The mapping of these seismic-reflection and well data has produced a refined Cenozoic sequence stratigraphic, seismic stratigraphic, and hydrogeologic framework of southeastern Florida. The upward transition from the Oldsmar Formation to the Avon Park Formation and the Arcadia Formation embodies the evolution from (1) a tropical to subtropical, shallow-marine, carbonate platform, represented by the Oldsmar and Avon Park Formations, to (2) a broad, temperate, mixed carbonate-siliciclastic shallow marine shelf, represented by the lower part of the Arcadia Formation, and to (3) a temperate, distally steepened carbonate ramp represented by the upper part of the Arcadia Formation. In the study area, the depositional sequences and seismic sequences have a direct correlation with hydrogeologic units. The approximate upper boundary of four principal permeable units of the Floridan aquifer system (Upper Floridan aquifer, Avon Park permeable zone, uppermost major permeable zone of the Lower Floridan aquifer, and Boulder Zone) have sequence stratigraphic and seismic-reflection signatures that were identified on cross sections, mapped, or both, and therefore the sequence stratigraphy and seismic stratigraphy were used to guide the development of a refined spatial representation of these hydrogeologic units. In all cases, the permeability of the four permeable units is related to stratiform megaporosity generated by ancient dissolution of carbonate rock associated with subaerial exposure and unconformities at the upper surfaces of carbonate depositional cycles of several 1U.S. Geological Survey. 2Cherokee Nation Businesses, Contractor to the U.S. Geological Survey. 3Jarer Biostrat, Inc., Contractor to the U.S. Geological Survey. 4Walker Marine Geophysical Company, Contractor to the Miami-Dade County Water and Sewer Department. 2 Sequence Stratigraphy, Seismic Stratigraphy, and Seismic Structures of the Lower Intermediate Confining Unit. . . hierarchical scales ranging from high-frequency cycles to depositional sequences. Additionally, interparticle porosity also contributes substantially to the stratiform permeability in much of the Upper Floridan aquifer. Information from seismic stratigraphy allowed 3D geomodeling of hydrogeologic units\u2014 an approach never before applied to this area. Notably, the 3D geomodeling provided 3D visualizations and geocellular models of the depositional sequences, hydrostratigraphy, and structural features. The geocellular data could be used to update the hydrogeologic structure inherent to groundwater flow simulations that are designed to address the sustainability of the water resources of the Floridan aquifer system. Two kinds of pathways that could enable upward cross-formational flow of injected treated wastewater from the Boulder Zone have been identified in the 80 miles of high-resolution seismic data collected for this study: a near-vertical reverse fault and karst collapse structures. The single reverse fault, inferred to be of tectonic origin, is in extreme northeastern Broward County and has an offset of about 19 feet at the level of the Arcadia Formation. Most of the 17 karst collapse structures identified manifest as columniform, vertically stacked sagging seismic reflections that span early Eocene to Miocene age rocks equivalent to much of the Floridan aquifer system and the lower part of the overlying intermediate confining unit. In some cases, the seismic-sag structures extend upward into strata of Pliocene age. The seismic-sag structures are interpreted to have a semicircular shape in plan view on the basis of comparison to (1) other seismic-sag structures in southeastern Florida mapped with two 2D seismic cross lines or 3D data, (2) comparison to these structures located in other carbonate provinces, and (3) plausible extensional ring faults detected with multi-attribute analysis. The seismic-sag structures in the study area have heights as great as 2,500 vertical feet, though importantly, one spans about 7,800 feet. Both multi-attribute analysis and visual detection of offset of seismic reflections within the seismic-sag structures indicate faults and fractures are associated with many of the structures. Multi-attribute analysis highlighting chimney fluid pathways also indicates that the seismic-sag structures have a high probability for potential vertical cross-formational fluid flow along the faulted and fractured structures. A collapse of the seismic-sag structures within a deep burial setting evokes an origin related to hypogenic karst processes by ascending flow of subsurface fluids. In addition, paleo-epigenic karst related to major regional subaerial unconformities within the Florida Platform generated collapse structures (paleo-sinkholes) that are much smaller in scale than the cross-formational seismic-sag structures. Introduction The source of drinking water in southeastern Florida primarily comes from the shallow Biscayne aquifer of the surficial aquifer system, whereas the Upper Floridan aquifer of the deeper Floridan aquifer system provides only a relatively minor volume (figs. 1 and 2). The Biscayne aquifer is a sole source aquifer in southeastern Florida (Federal Register Notice, 1979) and, as a protective measure, the South Florida Water Management District\u2019s Regional Water Availability Rule 1, adopted in 2007, limits urban water withdrawals from the Biscayne aquifer to pre-2006 levels (Broward Water Resources Task Force, 2010). In addition, legislation adopted by the State of Florida mandates the elimination of ocean outfalls of treated wastewater by 2025. These mandated changes have advanced the use of the more deeply buried Floridan aquifer system for the purposes of freshwater supply from the Upper Floridan aquifer and treated wastewater storage in the Boulder Zone of the Lower Floridan aquifer (fig. 2). The year 1971 marked the beginning of the use of deep well injection of treated wastewater into the highly transmissive Boulder Zone in southern Florida (fig. 2, Meyer, 1974). Since the 1990s, however, wastewater injection into the Boulder Zone in southeastern Florida has been detected at three treated wastewater injection utilities in the brackish (brackish water contains dissolved-solids concentrations that range from 1,000 to 10,000 milligrams per liter) upper part of the Floridan aquifer system designated for potential use as drinking water (Maliva and others, 2007; Walsh and Price, 2010). At a time when usage of the Boulder Zone for treated wastewater disposal is increasing and utilization of the upper brackish part of the Floridan aquifer system for drinking water is intensifying, the possibility of upward movement of treated wastewater brings new urgency to understanding the nature of cross-formational fluid flow and identifying possible fluid pathways from the Boulder Zone to the upper brackish part of the Floridan aquifer system. In Broward County, the Floridan aquifer system (figs. 1 and 2) is receiving increased attention as a result of regulatory restrictions on water-supply withdrawals and treated wastewater management practices. However, the integrity of the Floridan aquifer system for use either as a water-supply resource or wastewater repository (or both) is not well understood. Structural geologic anomalies (faults, fractures, and karst collapse structures) within the Floridan aquifer system in southeastern Florida are well documented (Cunningham and Walker, 2009; Cunningham and others, 2012; Reese and Cunningham, 2013, 2014; Cunningham, 2015) and present a potential risk for vertical cross-formational transport of undesirable fluids through the aquifer. The karst collapse structures are defined on seismic-reflection profiles as columniform, seismic-sag structures (McDonnell and others, 2007). Moreover, because of the risk posed by limited stratigraphic knowledge of the physic", "keyphrases": ["seismic stratigraphy", "aquifer system", "sequence stratigraphy"]}
{"id": "paleo.012779", "title": "Paleoceanography of the Late Cretaceous northwestern Tethys Ocean: Seasonal upwelling or steady thermocline?", "abstract": "In this study we attempted to assess whether seasonal upwelling or a steady thermocline persisted at the western margin of the Tethys Ocean during the late Turonian\u2013early Coniacian interval. For this scope, we employed novel and published stable oxygen isotope (\u03b418O) data of various organisms (bivalves, bivalves, brachiopods, fish and belemnites). New seasonally resolved temperature estimates were based on the \u03b418O record of sequentially sampled inoceramid (Inoceramus sp.) and rudist (Hippurites resectus) shells from the Scaglia Rossa and Gosau deposits of northern Italy and western Austria, respectively. Diagenetic screening was performed using reflected light, cathodoluminescence (CL), scanning electron microscopy (SEM) and stable isotope analysis. Originally preserved \u03b413C and \u03b418O values were used to characterize the lifestyle of the bivalves and detect vital effects that could have biased oxygen isotope-based temperature reconstructions. Inoceramid \u03b418O values provide\u2013for the first time\u2013information on temperatures of Tethyan benthic waters, which were, on average, 14.4 \u00b1 0.6 \u00b0C and fluctuated seasonally within a range of less than 2 \u00b0C. Such a thermal regime is in line with the temperatures postulated for late Turonian boreal water masses and support the existence of a cold water supply from the North Atlantic to the Tethyan bottom. Bottom cooling, however, did not affect the shallow water environment. In fact, the rudist-based temperature estimates for shallow water environment revealed a mean annual range of 11 \u00b0C, between 24 and 35 \u00b0C (assuming a seasonally constant \u03b418Ow = 1.0 \u2030), which are among the warmest temperatures recorded over the entire Late Cretaceous. Our findings, thus, suggest a strong thermal and food web decoupling between the two environments. The absence of a seasonal vertical homogenization of different water bodies suggests the existence of a steady thermocline and, therefore, contrasts with the presence of an active coastal upwelling in the region as hypothesized by previous authors.", "keyphrases": ["tethys ocean", "seasonal upwelling", "steady thermocline"]}
{"id": "10.1073/pnas.1524165113", "title": "Pitfalls reconstructing the last common ancestor of chimpanzees and humans", "abstract": "The morphological nature of the last common ancestor (LCA) of chimpanzees/bonobos and humans is a fascinating topic in human evolution. Available evidence suggests that both lineages share a LCA that lived in Africa \u223c8\u20136 Myr. However, the hominoid fossil record of this time period is inadequate, prompting the use of novel methodological approaches to reconstruct the anatomy of this key ancestor. In a recent example, Young et al. (1) claim that \u201cfossil hominin shoulders support an African ape-like last common ancestor of humans and chimpanzees.\u201d Although I applaud these authors for implementing novel comparative methods to paleoanthropology, fundamental aspects of the experimental design were disregarded, leading to biased conclusions. Herein I provide constructive criticisms on that study, also addressing recurrent pitfalls in the field, to help redirect future research on human paleobiology.", "keyphrases": ["last common ancestor", "chimpanzee", "pitfall"]}
{"id": "paleo.003366", "title": "Extreme growth plasticity in the early branching sauropodomorph Massospondylus carinatus", "abstract": "There is growing evidence of developmental plasticity in early branching dinosaurs and their outgroups. This is reflected in disparate patterns of morphological and histological change during ontogeny. In fossils, only the osteohistological assessment of annual lines of arrested growth (LAGs) can reveal the pace of skeletal growth. Some later branching non-bird dinosaur species appear to have followed an asymptotic growth pattern, with declining growth rates at increasing ontogenetic ages. By contrast, the early branching sauropodomorph Plateosaurus trossingensis appears to have had plastic growth, suggesting that this was the plesiomorphic condition for dinosaurs. The South African sauropodomorph Massospondylus carinatus is an ideal taxon in which to test this because it is known from a comprehensive ontogenetic series, it has recently been stratigraphically and taxonomically revised, and it lived at a time of ecosystem upheaval following the end-Triassic extinction. Here, we report on the results of a femoral osteohistological study of M. carinatus comprising 20 individuals ranging from embryo to skeletally mature. We find major variability in the spacing of the LAGs and infer disparate body masses for M. carinatus individuals at given ontogenetic ages, contradicting previous studies. These findings are consistent with a high degree of growth plasticity in M. carinatus.", "keyphrases": ["growth plasticity", "sauropodomorph massospondylus carinatus", "ideal taxon", "variability", "body masse"]}
{"id": "10.1111/j.1365-294X.2012.05508.x", "title": "Same old Salmo? Changes in life history and demographic trends of North Iberian salmonids since the Upper Palaeolithic as revealed by archaeological remains and beast analyses", "abstract": "Life history traits determine fitness and hence the ability of populations and species to survive through adverse conditions. Therefore, identifying temporal changes in life history traits over large timescales is necessary to understand and predict the effect of current global change on wild populations. In this study, we compare life history traits between Palaeolithic and present\u2010day vertebrates, analysing the number of winters spent in the river and at sea by North Iberian salmonids (Salmo salar and Salmo trutta) from two separate time frames: the Upper Palaeolithic, based on archaeological remains, and the present day, based on sport catches. The river stage did not change significantly, but the marine period has been shortened in modern anadromous specimens, accordingly shortening mean generation time. Population growth rates have been estimated through Bayesian analyses of the mitochondrial DNA control region of modern specimens for the two Salmo species using two different mutation rates (1% and 3.6%). Coincidence of coalescent Ne estimates with independent Ne calculated from catches suggests that the 3.6% mutation rate fits better the evolution of the studied populations. Population growth rate declines would have occurred in the last millennium and could be explained by a combination of climatic events and anthropogenic activities.", "keyphrases": ["north iberian salmonid", "upper palaeolithic", "archaeological remain"]}
{"id": "10.1111/j.1365-2699.2010.02432.x", "title": "An evaluation of new parsimony\u2010based versus parametric inference methods in biogeography: a case study using the globally distributed plant family Sapindaceae", "abstract": "Aim\u2002 Recently developed parametric methods in historical biogeography allow researchers to integrate temporal and palaeogeographical information into the reconstruction of biogeographical scenarios, thus overcoming a known bias of parsimony\u2010based approaches. Here, we compare a parametric method, dispersal\u2013extinction\u2013cladogenesis (DEC), against a parsimony\u2010based method, dispersal\u2013vicariance analysis (DIVA), which does not incorporate branch lengths but accounts for phylogenetic uncertainty through a Bayesian empirical approach (Bayes\u2010DIVA). We analyse the benefits and limitations of each method using the cosmopolitan plant family Sapindaceae as a case study.", "keyphrases": ["biogeography", "case study", "plant family sapindaceae"]}
{"id": "paleo.012370", "title": "A Devonian predatory fish provides insights into the early evolution of modern sarcopterygians", "abstract": "A 409-million-year-old predatory fish provides unique insights into the early evolution of modern lobe-finned fishes. Crown or modern sarcopterygians (coelacanths, lungfishes, and tetrapods) differ substantially from stem sarcopterygians, such as Guiyu and Psarolepis, and a lack of transitional fossil taxa limits our understanding of the origin of the crown group. The Onychodontiformes, an enigmatic Devonian predatory fish group, seems to have characteristics of both stem and crown sarcopterygians but is difficult to place because of insufficient anatomical information. We describe the new skull material of Qingmenodus, a Pragian (~409-million-year-old) onychodont from China, using high-resolution computed tomography to image internal structures of the braincase. In addition to its remarkable similarities with stem sarcopterygians in the ethmosphenoid portion, Qingmenodus exhibits coelacanth-like neurocranial features in the otic region. A phylogenetic analysis based on a revised data set unambiguously assigns onychodonts to crown sarcopterygians as stem coelacanths. Qingmenodus thus bridges the morphological gap between stem sarcopterygians and coelacanths and helps to illuminate the early evolution and diversification of crown sarcopterygians.", "keyphrases": ["predatory fish", "early evolution", "sarcopterygian"]}
{"id": "10.1017/S0094837300008186", "title": "A kinetic model of Phanerozoic taxonomic diversity. III. Post-Paleozoic families and mass extinctions", "abstract": "A three-phase kinetic model with time-specific perturbations is used to describe large-scale patterns in the diversification of Phanerozoic marine families. The basic model assumes that the Cambrian, Paleozoic, and Modern evolutionary faunas each diversified logistically as a consequence of early exponential growth and of later slowing of growth as the ecosystems became filled; it also assumes interaction among the evolutionary faunas such that expansion of the combined diversities of all three faunas above any single fauna's equilibrium caused that fauna's diversity to begin to decline. This basic model adequately describes the diversification of the evolutionary faunas through the Paleozoic Era as well as the asymmetrical rise and fall of background extinction rates through the entire Phanerozoic. Declines in diversity and changes in faunal dominance associated with mass extinctions can be accommodated in the model with short-term accelerations in extinction rates or declines in equilibria. Such accelerations, or perturbations, cause diversity to decline exponentially and then to rebound sigmoidally following release. The amount of decline is dependent on the magnitude and duration of the perturbation, the timing of the perturbation with respect to the diversification of the system, and the system's initial per-taxon rates of diversification and turnover. When applied to the three-phase model, such perturbations describe the changes in diversity and faunal dominance during and after major mass extinctions, the long-term rise in total diversity following the Late Permian and Norian mass extinctions, and the peculiar diversification and then decline of the remnants of the Paleozoic fauna during the Mesozoic and Cenozoic Eras. The good fit of this model to data on Phanerozoic familial diversity suggests that many of the large-scale patterns of diversification seen in the marine fossil record of animal families are simple consequences of nonlinear interrelationships among a small number of parameters that are intrinsic to the evolutionary faunas and are largely (but not completely) invariant through time.", "keyphrases": ["kinetic model", "phanerozoic", "mass extinction", "evolutionary faunas", "rise"]}
{"id": "10.1111/j.1095-8312.2000.tb00207.x", "title": "Speciation of Phlebotomus sandflies of the subgenus Larroussius coincided with the late Miocene-Pliocene aridification of the Mediterranean subregion", "abstract": "Abstract The phylogeny and mode of speciation of Mediterranean Phlebotomus of the subgenusLarroussius were inferred by comparative sequence analyses of a fragment of mitochondrial DNA (Cytochrome b) and of a nuclear gene (Elongation factor alpha). The molecular phylogenies were congruent basally, where their clades matched the species complexes defined by a few genitalic characters of each sex. Reticulate evolution was suggested for the most derived species complex (Phlebotomus perniciosus): the molecular phylogenies were incongruent, and mitochondrial-marker distribution was consistent with introgressive hybridizations not between sister species but between species whose ranges now overlap or abut. By considering the molecular phylogenies, the mitochondrial molecular clock and the ecological niches of the species, as well as the historical biogeography and palaeoecology of the Mediterranean subregion, we propose that the derived lineages arose from a sequential series of speciation events associated with habitat shifts promoted by progressive aridification. This \u00abtaxon pulse\u00bb-like speciation occurred in the Pliocene, later than previously proposed in a vicariance hypothesis that invoked only tectonic events, but too early for Pleistocene Ice-age refugia to have played any role other than the isolation of geographical races. Speciation occurred before the proposed divergence of members of the Leishmania donovani complex and this helped to rule out any vector-parasite co-speciation or co-cladogenesis.", "keyphrases": ["ecological niche", "speciation", "mediterranean phlebotomus specie", "mediterranean sandfly fauna", "miocene diversification"]}
{"id": "10.1017/S0016756816000753", "title": "New material of Ophisaurus, Anguis and Pseudopus (Squamata, Anguidae, Anguinae) from the Miocene of the Czech Republic and Germany and systematic revision and palaeobiogeography of the Cenozoic Anguinae", "abstract": "Abstract Four species of Ophisaurus, O. fejfari, O. spinari, O. robustus and O. holeci, are recognized on the basis of parietals from the Early Miocene of the Czech Republic and Germany. The fifth species, O. acuminatus, is described from the Late Miocene of Germany, but its parietal is not preserved. This paper describes new O. fejfari, O. spinari, O. robustus and O. holeci specimens from the Early and Middle Miocene of the Czech Republic and Germany. The O. fejfari and O. holeci parietals from Germany are the first records of these species outside the Czech Republic. This paper provides a significant contribution to the understanding of both interspecific and intraspecific Ophisaurus variability in the Cenozoic of Europe. A well-preserved parietal of Anguis rarus sp. nov. is described from the Early Miocene of Germany. This is the first record of the parietal of Anguis in the Cenozoic. A new parietal from the Middle Miocene of Germany is described as Pseudopus sp. It differs from the contemporaneous P. laurillardi only in the absence of the large and distinctly laterally projecting anterolateral processes of the parietal. In the Miocene, Ophisaurus and Pseudopus exhibit a higher diversity than that of the preceding geological periods of the Cenozoic. Besides, Ophisaurus emigrates from Europe to (1) Asia and via the Bering Strait to North America, and (2) North Africa during the Oligocene and Miocene. By contrast, Anguis and Pseudopus are limited to Eurasia. The palaeobiogeography of members of Anguinae is discussed.", "keyphrases": ["anguinae", "miocene", "palaeobiogeography", "pliocene", "parietal bone"]}
{"id": "paleo.001178", "title": "Urchins on the edge: an echinoid fauna with a mixed environmental signal from the Eocene of Jamaica", "abstract": "An echinoid fauna from the Early-Middle Eocene of Jamaica has yielded six species of echinoid: the phymosomatoid Acanthechinus peloria (Arnold and Clark); the oligopygoid Oligopygus sp.; the clypeasteroids Fibularia jacksoni Hawkins and Neolaganum sp.; and the spatangoids Eupatagus alatus Arnold and Clark and Eupatagus sp. cf. E. clevei (Cotteau). Eupatagus alatus has a relatively low test, is broadest posterior of centre, and lacks an anterior sulcus; Eupatagus sp. cf. clevei is relatively higher and more inflated, more parallel-sided, and blunter anteriorly with an anterior sulcus. The discovery of F. jacksoni and Neolaganum sp. together with Oligopygus sp. is unexpected, as these species commonly have different ecological niches in the Eocene of Jamaica. In previous examples described from the Eocene succession of the island, oligopygoids favoured high-energy shelf edge settings, whereas Fibularia and neolaganids prefered lowenergy lagoonal settings. The assemblage as a whole likely represents an Early-Mid Eocene echinoid fauna inhabiting a shallow island shelf sea, in a transition between shelf edge and lagoonal setting.", "keyphrases": ["echinoid fauna", "eocene", "clypeasteroid", "van den"]}
{"id": "10.1080/03115518.2016.1180034", "title": "The mandible and dentition of the Early Cretaceous monotreme Teinolophos trusleri", "abstract": "Rich, T.H., Hopson, J.A., Gill, P.G., Trusler, P., Rogers-Davidson, S., Morton, S., Cifelli, R.L., Pickering, D., Kool, L., Siu, K., Burgmann, F.A., Senden, T., Evans, A.R., Wagstaff, B.E., Seegets-Villiers, D., Corfe, I.J., Flannery, T.F., Walker, K., Musser, A.M., Archer, M., Pian, R. & Vickers-Rich, P., June 2016. The mandible and dentition of the Early Cretaceous monotreme Teinolophos trusleri. Alcheringa 40, xx\u2013xx. ISSN 0311-5518. The monotreme Teinolophos trusleri Rich, Vickers-Rich, Constantine, Flannery, Kool & van Klaveren, 1999 from the Early Cretaceous of Australia is redescribed and reinterpreted here in light of additional specimens of that species and compared with the exquisitely preserved Early Cretaceous mammals from Liaoning Province, China. Together, this material indicates that although T. trusleri lacked a rod of postdentary bones contacting the dentary, as occurs in non-mammalian cynodonts and basal mammaliaforms, it did not share the condition present in all living mammals, including monotremes, of having the three auditory ossicles, which directly connect the tympanic membrane to the fenestra ovalis, being freely suspended within the middle ear cavity. Rather, T. trusleri appears to have had an intermediate condition, present in some Early Cretaceous mammals from Liaoning, in which the postdentary bones cum ear ossicles retained a connection to a persisting Meckel\u2019s cartilage although not to the dentary. Teinolophos thus indicates that the condition of freely suspended auditory ossicles was acquired independently in monotremes and therian mammals. Much of the anterior region of the lower jaw of Teinolophos is now known, along with an isolated upper ultimate premolar. The previously unknown anterior region of the jaw is elongated and delicate as in extant monotremes, but differs in having at least seven antemolar teeth, which are separated by distinct diastemata. The dental formula of the lower jaw of Teinolophos trusleri as now known is i2 c1 p4 m5. Both the deep lower jaw and the long-rooted upper premolar indicate that Teinolophos, unlike undoubted ornithorhynchids (including the extinct Obdurodon), lacked a bill. Thomas H. Rich [trich@museum.vic.gov.au], Sally Rogers-Davidson [srogers@museum.vic.gov.au], David Pickering [dpick@museum.vic.gov.au], Timothy F. Flannery [tim.flannery@textpublishing.com.au], Ken Walker [kwalker@museum.vic.gov.au], Museum Victoria, PO Box 666, Melbourne, Victoria 3001, Australia; James A. Hopson [jhopson@uchicago.edu], Department of Organismal Biology & Anatomy, University of Chicago,1025 East 57th Street, Chicago, IL 60637, USA; Pamela G. Gill [pam.gill@bristol.ac.uk], School of Earth Sciences, University of Bristol, Bristol BS8 1RJ, U.K. and Earth Science Department, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; Peter Trusler [peter@petertrusler.com.au], Lesley Kool [koollesley@gmail.com], Doris Seegets-Villiers [doris.seegets-villiers@monash.edu], Patricia Vickers-Rich [pat.rich@monash.edu], School of Earth, Atmosphere and Environment, Monash University, Victoria 3800, Australia; Steve Morton [steve.morton@monash.edu], Karen Siu [karen.siu@monash.edu], School of Physics and Astronomy, Monash University, Victoria 3800, Australia; Richard L. Cifelli [rlc@ou.edu] Sam Noble Oklahoma Museum of Natural History, University of Oklahoma, Norman, OK 73072, USA; Flame A. Burgmann [flame.burgmann@monash.edu], Monash Centre for Electron Microscopy, 10 Innovation Walk, Monash University, Clayton, Victoria 3800, Australia; Tim Senden [Tim.Senden@anu.edu.au], Department of Applied Mathematics, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, Australian Capital Territory 0200, Australia; Alistair R. Evans [alistair.evans@monash.edu], School of Biological Sciences, Monash University, Victoria 3800, Australia; Barbara E. Wagstaff [wagstaff@unimelb.edu.au], School of Earth Sciences, The University of Melbourne, Victoria 3010, Australia; Ian J. Corfe [ian.corfe@helsinki.fi], Institute of Biotechnology, Viikinkaari 9, 00014, University of Helsinki, Finland; Anne M. Musser [anne.musser@austmus.gov.au], Australian Museum, 1 College Street, Sydney NSW 2010 Australia; Michael Archer [m.archer@unsw.edu.au], School of Biological, Earth, and Environmental Sciences, University of New South Wales, Sydney, NSW 2052, Australia; Rebecca Pian [rpian@amnh.org], Division of Paleontology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024-5192, USA. Received 7.4.2016; accepted 14.4.2016.", "keyphrases": ["mandible", "dentition", "monotreme teinolophos trusleri"]}
{"id": "paleo.009304", "title": "The Influence of Modularity on Cranial Morphological Disparity in Carnivora and Primates (Mammalia)", "abstract": "Background Although variation provides the raw material for natural selection and evolution, few empirical data exist about the factors controlling morphological variation. Because developmental constraints on variation are expected to act by influencing trait correlations, studies of modularity offer promising approaches that quantify and summarize patterns of trait relationships. Modules, highly-correlated and semi-autonomous sets of traits, are observed at many levels of biological organization, from genes to colonies. The evolutionary significance of modularity is considerable, with potential effects including constraining the variation of individual traits, circumventing pleiotropy and canalization, and facilitating the transformation of functional structures. Despite these important consequences, there has been little empirical study of how modularity influences morphological evolution on a macroevolutionary scale. Here, we conduct the first morphometric analysis of modularity and disparity in two clades of placental mammals, Primates and Carnivora, and test if trait integration within modules constrains or facilitates morphological evolution. Principal Findings We used both randomization methods and direct comparisons of landmark variance to compare disparity in the six cranial modules identified in previous studies. The cranial base, a highly-integrated module, showed significantly low disparity in Primates and low landmark variance in both Primates and Carnivora. The vault, zygomatic-pterygoid and orbit modules, characterized by low trait integration, displayed significantly high disparity within Carnivora. 14 of 24 results from analyses of disparity show no significant relationship between module integration and morphological disparity. Of the ten significant or marginally significant results, eight support the hypothesis that integration within modules constrains morphological evolution in the placental skull. Only the molar module, a highly-integrated and functionally important module, showed significantly high disparity in Carnivora, in support of the facilitation hypothesis. Conclusions This analysis of within-module disparity suggested that strong integration of traits had little influence on morphological evolution over large time scales. However, where significant results were found, the primary effect of strong integration of traits was to constrain morphological variation. Thus, within Primates and Carnivora, there was some support for the hypothesis that integration of traits within cranial modules limits morphological evolution, presumably by limiting the variation of individual traits.", "keyphrases": ["modularity", "carnivora", "primates"]}
{"id": "paleo.010175", "title": "Micromeryx? eiselei\u2014A new moschid species from Steinheim am Albuch, Germany, and the first comprehensive description of moschid cranial material from the Miocene of Central Europe", "abstract": "Moschids are enigmatic pecoran ruminants whose phylogeny is still not fully understood. So far we know only little of the family\u2019s early evolutionary history and the origin of the modern genus, Moschus. Here we present a comprehensive description of cranial material, including the ear region and the dentition, of fossil moschid material from the Middle Miocene locality Steinheim am Albuch (13.5 Ma; Germany). This study provides the first exhaustive dataset for the cranial osteology of Micromeryx flourensianus, the most likely oldest true moschid. It furthermore reveals the presence of a second, so far undescribed moschid species, we here name Micromeryx? eiselei, in the abundant material from the locality. The two taxa can be clearly distinguished by characters of the skull, the ear region, the dentition, as well as by size. This evidences the sympatric occurrence of two moschid species in the locality Steinheim am Albuch.", "keyphrases": ["moschid specie", "miocene", "evolutionary history", "micromeryx", "eurasia"]}
{"id": "10.5479/si.00810266.95.1", "title": "New materials of Masiakasaurus knopfleri Sampson, Carrano, and Forster, 2001, and implications for the morphology of the Noasauridae (Theropoda: Ceratosauria)", "abstract": "Smithsonian Contributions to Paleobiology, no. 95: viii + 53 pages, 26 figures, 3 tables. New materials of Masiakasaurus knopfleri Sampson, Carrano, and Forster, 2001, and implications for the morphology of the Noasauridae (Theropoda: Ceratosauria).", "keyphrases": ["masiakasaurus knopfleri sampson", "noasauridae", "theropoda"]}
{"id": "paleo.006791", "title": "Fire in the paradise: evidence of repeated palaeo-wildfires from the Araripe Fossil Lagerst\u00e4tte (Araripe Basin, Aptian-Albian), Northeast Brazil", "abstract": "Reports on Cretaceous charcoals are relatively common on a global scale and have been increasing in recent years. Fossil charcoal from the Early Cretaceous mostly belongs to conifers (and other gymnosperms) and ferns whereas angiosperms become more common only during the Late Cretaceous. However, so far, reports of Cretaceous macroscopic charcoal are rare (three) for South America. Here, charcoal is identified from the Crato, Ipubi and Romualdo formations of the Early Cretaceous Santana Group within the Araripe Basin, Brazil. The presence of charcoal provides for the first time compelling evidence for the repeated occurrence of Early Cretaceous palaeo-wildfires in this region. The charred wood remains were identified as belonging to gymnosperms, which were important components of the palaeoflora during the Cretaceous in Northeast Brazil. The results presented here provide additional evidence for the occurrence of palaeo-wildfires in Northern Gondwana during the Early Cretaceous, increasing our understanding for the relevance of such events and their influence on palaeoenvironmental dynamics.", "keyphrases": ["palaeo-wildfire", "araripe basin", "northeast brazil"]}
{"id": "paleo.003104", "title": "Functional morphology, ontogeny and evolution of mantis shrimp\u2010like predators in the Cambrian", "abstract": "Abstract:\u2002 We redescribe the morphology of Yohoia tenuis (Chelicerata sensu lato) from the Cambrian Burgess Shale Lagerst\u00e4tte. The morphology of the most anterior, prominent, so\u2010called great appendage changes throughout ontogeny. While its principal morphology remains unaltered, the length ratios of certain parts of the great appendage change significantly. Furthermore, it possesses a special jack\u2010knifing mechanism, i.e. an elbow joint: the articulation between the distal one of the two peduncle elements and the most proximal of the four spine\u2010bearing claw elements. This morphology might have enabled the animal to hunt like a modern spearer\u2010type mantis shrimp, an analogy enhanced by the similarly large and protruding eyes. For comparison, details of specimens of selected other great\u2010appendage arthropods from the Lower Cambrian Chengjiang Lagerst\u00e4tte have been investigated using fluorescence microscopy. This revealed that the morphology of the great appendage of Y. tenuis is much like that of the Chengjiang species Fortiforceps foliosa and Jianfengia multisegmentalis. The morphology of the great appendage of the latter is even more similar to the morphology developed in early developmental stages of Y. tenuis, while the morphology of the great appendage of F. foliosa is more similar to that of later developmental stages of Y. tenuis. The arrangement of the elbow joint supports the view that the great appendage evolved into the chelicera of Chelicerata sensu stricto, as similar joints are found in various ingroup taxa such as Xiphosura, Opiliones or Palpigradi. With this, it also supports the interpretation of the great appendage to be homologous with the first appendage of other arthropods.", "keyphrases": ["morphology", "ontogeny", "chelicerata sensu", "great appendage"]}
{"id": "10.2110/palo.2011.p11-052r", "title": "FEEDING TRACES AND PALEOBIOLOGY OF A CRETACEOUS (CENOMANIAN) CROCODYLIFORM: EXAMPLE FROM THE WOODBINE FORMATION OF TEXAS", "abstract": "Abstract Direct evidence of behavior in extinct tetrapods is rare. However, these traces can inform a variety of research questions touching on paleoecology, taphonomy, and functional morphology. Here we present fossil specimens from the Upper Cretaceous (Cenomanian) Woodbine Formation that exhibit tooth marks consistent with predation by a new taxon of large crocodyliform currently under study. Collected from the recently discovered Arlington Archosaur Site, the marked bones were largely found in a single peat horizon and in close association with the new crocodyliform. The feeding traces themselves consist of pits, scores, and punctures that occur on multiple turtle shell fragments and two dinosaur limb bones. The pattern of marks and the breakage on turtle carapaces and plastra suggest that they were crushed, whereas the marks on dinosaur bones indicate possible dismemberment. These interpretations and the association with a crocodyliform trace maker are based on observations of feeding behaviors and accompanying, diagnostic bite mark patterns made by extant crocodylians. The morphology of the new crocodyliform taxon and the distribution of bite marks indicates it was likely a generalist: an opportunistic predator that fed on a variety of prey, including turtles and dinosaurs. Given this evidence and the paleoenvironmental setting, the ecology of the large crocodyliform from the Woodbine Formation was likely most similar to that of fossil and living crocodylians inhabiting delta-plain environments. Not only were these crocodyliforms likely significant predators in the Woodbine paleoecosystem, they also played an important taphonomic role in the assembly of vertebrate remains from the surrounding community.", "keyphrases": ["cenomanian", "crocodyliform", "woodbine formation", "turtle shell fragment"]}
{"id": "paleo.002687", "title": "Age and pattern of the southern high-latitude continental end-Permian extinction constrained by multiproxy analysis", "abstract": "Past studies of the end-Permian extinction (EPE), the largest biotic crisis of the Phanerozoic, have not resolved the timing of events in southern high-latitudes. Here we use palynology coupled with high-precision CA-ID-TIMS dating of euhedral zircons from continental sequences of the Sydney Basin, Australia, to show that the collapse of the austral Permian Glossopteris flora occurred prior to 252.3 Ma (~370 kyrs before the main marine extinction).\nWeathering proxies indicate that floristic changes occurred during a brief climate perturbation in a regional alluvial landscape that otherwise experienced insubstantial change in fluvial style, insignificant reorganization of the depositional surface, and no abrupt aridification. Palaeoclimate modelling suggests a moderate shift to warmer summer temperatures and amplified seasonality in temperature across the EPE, and warmer and wetter conditions for all seasons into the Early Triassic. The terrestrial EPE and a succeeding peak in Ni concentration in the Sydney Basin correlate, respectively, to the onset of the primary extrusive and intrusive phases of the Siberian Traps Large Igneous Province.", "keyphrases": ["end-permian extinction", "sydney basin", "australia"]}
{"id": "10.1130/b30915.1", "title": "New Age Constraints for the Salamanca Formation and Lower R\u00edo Chico Group in the Western San Jorge Basin, Patagonia, Argentina: Implications for Cretaceous-Paleogene Extinction Recovery and Land Mammal Age Correlations", "abstract": "The Salamanca Formation of the San Jorge Basin (Patagonia, Argentina) preserves critical records of Southern Hemisphere Paleocene biotas, but its age remains poorly resolved, with estimates ranging from Late Cretaceous to middle Paleocene. We report a multi-disciplinary geochronologic study of the Salamanca Formation and overlying Rio Chico Group in the western part of the basin. New constraints include (1) an 40Ar/39Ar age determination of 67.31 \u00b1 0.55 Ma from a basalt flow underlying the Salamanca Formation, (2) micropaleontological results indicating an early Danian age for the base of the Salamanca Formation, (3) laser ablation HR-MC-ICP-MS (high resolution-multi collector-inductively coupled plasma-mass spectrometry) U-Pb ages and a high-resolution TIMS (thermal ionization mass spectrometry) age of 61.984 \u00b1 0.041(0.074)[0.100] Ma for zircons from volcanic ash beds in the Penas Coloradas Formation (Rio Chico Group), and (4) paleomagnetic results indicating that the Salamanca Formation in this area is entirely of normal polarity, with reversals occurring in the Rio Chico Group. Placing these new age constraints in the context of a sequence stratigraphic model for the basin, we correlate the Salamanca Formation in the study area to Chrons C29n and C28n, with the Banco Negro Inferior (BNI), a mature widespread fossiliferous paleosol unit at the top of the Salamanca Formation, corresponding to the top of Chron C28n. The diverse paleobotanical assemblages from this area are here assigned to C28n (64.67\u201363.49 Ma), \u223c2\u20133 million years older than previously thought, adding to growing evidence for rapid Southern Hemisphere floral recovery after the Cretaceous-Paleogene extinction. Important Peligran and \u201cCarodnia\u201d zone vertebrate fossil assemblages from coastal BNI and Penas Coloradas exposures are likely older than previously thought and correlate to the early Torrejonian and early Tiffanian North American Land Mammal Ages, respectively.", "keyphrases": ["salamanca formation", "paleocene", "study area"]}
{"id": "10.1080/02724634.1995.10011239", "title": "Petrosal and Inner Ear of a Squalodontoid Whale: Implications for Evolution of Hearing in Odontocetes", "abstract": "ABSTRACT This study focuses on the petrosal and bony structures of the inner ear of a fossil squalodontoid whale (Odontoceti, Mammalia) from the Chandler Bridge Formation (late Oligocene) of South Carolina. High frequency hearing in toothed whales (odontocetes) has been attributed to specialized bony structures and their associated membranes in the inner ear cochlea. Whales also have very peculiar vestibule and semicircular canals by comparison to terrestrial mammals. By using serial grinding and computerized reconstruction, we identified in this fossil squalodontoid whale several inner ear structures specialized for high frequency hearing: 1) a well developed secondary bony lamina for the basilar membrane in the basal \u00be cochlear turn; 2) numerous foramina for the ganglion cells of the auditory nerve and a partially preserved spiral ganglion canal; 3) great size difference between the scala tympani and the scala vestibuli (including the scala media); and 4) wide separation between the cochlear turns. All ...", "keyphrases": ["inner ear", "squalodontoid whale", "petrosal"]}
{"id": "paleo.009238", "title": "Fossil evidence of elytra reduction in ship-timber beetles", "abstract": "Beetles (Coleoptera) comprise about one quarter of all described animal species. One of the main contributors to their evolutionary success is the elytra, or hardened forewings, which have protective functions while maintaining their ability to fly. Unlike other beetles, some ship-timber beetles (Lymexylidae) have extremely small elytra and largely exposed functional hindwings. There is little fossil evidence illuminating the evolutionary history of short elytra in lymexylids. Here, I report five well-preserved lymexylid fossils in mid-Cretaceous and Cenozoic ambers from Myanmar (ca. 99 million years ago [Mya]), Russia (ca. 44 Mya), and the Dominican Republic (ca. 16 Mya). Three Cretaceous fossils have strongly reduced, shortened elytra, with unexpected variation in elytral size and shape, whereas very small, modified elytra are found only in much younger Dominican amber. These morphologically diverse extinct lymexylids shed new light on the early origin and evolutionary history of elytra reduction and its diverse variation in the ship-timber beetles. Based on the striking morphological similarities with extant lymexylids, these extinct taxa might have had the same, or similar, ecological, behavioural, and flight modes as the extant ship-timber beetles.", "keyphrases": ["elytra reduction", "ship-timber beetle", "fossil evidence"]}
{"id": "paleo.003805", "title": "Relationships of mass properties and body proportions to locomotor habit in terrestrial Archosauria", "abstract": "Throughout their 250 Myr history, archosaurian reptiles have exhibited a wide array of body sizes, shapes, and locomotor habits, especially in regard to terrestriality. These features make Archosauria a useful clade with which to study the interplay between body size, shape, and locomotor behavior, and how this interplay may have influenced locomotor evolution. Here, digital volumetric models of 80 taxa are used to explore how mass properties and body proportions relate to each other and locomotor posture in archosaurs. One-way, nonparametric, multivariate analysis of variance, based on the results of principal components analysis, shows that bipedal and quadrupedal archosaurs are largely distinguished from each other on the basis of just four anatomical parameters ( p < 0.001): mass, center of mass position, and relative forelimb and hindlimb lengths. This facilitates the development of a quantitative predictive framework that can help assess gross locomotor posture in understudied or controversial taxa, such as the crocodile-line Batrachotomus (predicted quadruped) and Postosuchus (predicted biped). Compared with quadrupedal archosaurs, bipedal species tend to have relatively longer hindlimbs and a more caudally positioned whole-body center of mass, and collectively exhibit greater variance in forelimb lengths. These patterns are interpreted to reflect differing biomechanical constraints acting on the archosaurian Bauplan in bipedal versus quadrupedal groups, which may have shaped the evolutionary histories of their respective members.", "keyphrases": ["mass property", "body proportion", "locomotor habit"]}
{"id": "paleo.004366", "title": "Body-size trends of the extinct giant shark Carcharocles megalodon: a deep-time perspective on marine apex predators", "abstract": "The extinct shark Carcharocles megalodon is one of the largest marine apex predators ever to exist. Nonetheless, little is known about its body-size variations through time and space. Here, we studied the bodysize trends of C. megalodon through its temporal and geographic range to better understand its ecology and evolution. Given that this species was the last of the megatooth lineage, a group of species that shows a purported size increase through time, we hypothesized that C. megalodon also displayed this trend, increasing in size over time and reaching its largest size prior to extinction. We found that C. megalodon body-size distribution was left-skewed (suggesting a long-term selective pressure favoring larger individuals), and presented significant geographic variation (possibly as a result of the heterogeneous ecological constraints of this cosmopolitan species) over geologic time. Finally, we found that stasis was the general mode of size evolution of C. megalodon (i.e., no net changes over time), contrasting with the trends of the megatooth lineage and our hypothesis. Given that C. megalodon is a relatively long-lived species with a widely distributed fossil record, we further used this study system to provide a deep-time perspective to the understanding of the bodysize trends of marine apex predators. For instance, our results suggest that (1) a selective pressure in predatory sharks for consuming a broader range of prey may favor larger individuals and produce left-skewed distributions on a geologic time scale; (2) body-size variations in cosmopolitan apex marine predators may depend on their interactions with geographically discrete communities; and (3) the inherent characteristics of shark species can produce stable sizes over geologic time, regardless of the size trends of their lineages.", "keyphrases": ["shark carcharocles megalodon", "deep-time perspective", "marine apex predator", "otodus megalodon"]}
{"id": "paleo.001407", "title": "Gigantism, taphonomy and palaeoecology of Basiloceras, a new oncocerid genus from the Middle Devonian of the Tafilalt (Morocco)", "abstract": "The genus Basiloceras gen. nov. containing the two species B. goliath sp. nov. and B. david sp. nov. is described. It belongs to the Acleistoceratidae within the Oncocerida. Both species are from the Middle Devonian of the Tafilalt (Morocco). The genus exhibits a large interspecific size range between the small Eifelian B. david sp. nov. and the Givetian B. goliath sp. nov., the largest Devonian oncocerid currently known, altogether only second to some fragmentary remains of Calchasiceras from the Carboniferous of Russia. Several other large species are mainly known from the late Emsian of Bohemia and the Eifelian of Germany. The holotype of B. goliath sp. nov. contains numerous epicoles, trace fossils and shell debris, which are discussed in the context of its taphonomy. Compared to other oncocerids, Basiloceras is characterised by a short body chamber, which might be related to buoyancy regulation. In contrast to some older publications, we do not regard breviconic oncocerids with contracted aperture as benthic or nektobenthic animals, but instead, we think that they dwelled in the water column.", "keyphrases": ["basiloceras", "oncocerid", "middle devonian", "tafilalt"]}
{"id": "10.1111/j.1096-3642.2008.00412.x", "title": "A revision of the extinct Mesozoic family Prochydoridae Smirnov, 1992 (Crustacea: Cladocera) with a discussion of its phylogenetic position", "abstract": "This paper provides a revision of the extinct Mesozoic family Prochydoridae Smirnov, 1992 (Crustacea: Cladocera). Representatives of the two previously described genera, Prochydorus Smirnov, 1992 and Archeoxus Smirnov, 1992, are re-investigated from Khotont (Mongolia, Jurassic\u2013Cretaceous boundary). A new genus, Palaeorak gen. nov., is described from Khasurty (Asian Russia, Lower Cretaceous). The study provides evidence that the three known prochydorid genera show a subfamilial or familial level of morphological differentiation. Evidence is presented that the Prochydoridae form a specific lineage of cladocerans either separate from or basal to the order Anomopoda Sars, 1865. Nevertheless, a definitive conclusion of phylogenetic position awaits description of the prochydorid thoracic limbs, which are currently unknown.\u00a0\u00a9 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155, 253\u2013265.", "keyphrases": ["crustacea", "cladocera", "phylogenetic position"]}
{"id": "10.1163/9789047428664", "title": "The Evolutionary History of Nematodes: As revealed in stone, amber and mummies", "abstract": "Nematodes are one of the most abundant groups of invertebrates on the face of the earth. Their numbers are estimated to range from 1000 per cm2 in the sand-covered hydrogen sulphide 'black zone' beneath the ocean floors to 1.2 billion in a single hectare of soil. Estimates for their species diversity range from 100 000 to 10 million. The past history of nematodes is a mystery, since very few fossils have been discovered. This book establishes a solid base in palaeonematology with descriptions of 66 new fossil species and accounts of all previous fossil and subfossil nematodes from sedimentary deposits, coprolites, amber and mummies. It shows how nematode fossils can be used to establish lineages at various locations and time periods in the earth's history and when nematodes entered into symbiotic and parasitic associations with plants and animals.", "keyphrases": ["nematode", "amber", "mummy", "invertebrate"]}
{"id": "10.1111/j.1469-8137.2008.02496.x", "title": "Sensitivity of leaf size and shape to climate within Acer rubrum and Quercus kelloggii.", "abstract": "* Variation in the size and shape (physiognomy) of leaves has long been correlated to climate, and paleobotanists have used these correlations to reconstruct paleo-climate. Most studies focus on site-level means of largely nonoverlapping species sets. The sensitivity of leaf shape to climate within species is poorly known, which limits our general understanding of leaf-climate relationships and the value of intraspecific patterns for paleoclimate reconstructions. * The leaf physiognomy of two species whose native North American ranges span large climatic gradients (Acer rubrum and Quercus kelloggii) was quantified and correlated to mean annual temperature (MAT). Quercus kelloggii was sampled across a wide elevation range, but A. rubrum was sampled in strictly lowland areas. * Within A. rubrum, leaf shape correlates with MAT in a manner that is largely consistent with previous site-level studies; leaves from cold climates are toothier and more highly dissected. By contrast, Q. kelloggii is largely insensitive to MAT; instead, windy conditions with ample plant-available water may explain the preponderance of small teeth at high elevation sites, independent of MAT. * This study highlights the strong correspondence between leaf form and climate within some species, and demonstrates that intraspecific patterns may contribute useful information towards reconstructing paleoclimate.", "keyphrases": ["quercus kelloggii", "leaf shape", "cold climate"]}
{"id": "paleo.006740", "title": "A New Paleozoic Symmoriiformes (Chondrichthyes) from the Late Carboniferous of Kansas (USA) and Cladistic Analysis of Early Chondrichthyans", "abstract": "Background The relationships of cartilaginous fishes are discussed in the light of well preserved three-dimensional Paleozoic specimens. There is no consensus to date on the interrelationship of Paleozoic chondrichthyans, although three main phylogenetic hypotheses exist in the current literature: 1. the Paleozoic shark-like chondrichthyans, such as the Symmoriiformes, are grouped along with the modern sharks (neoselachians) into a clade which is sister group of holocephalans; 2. the Symmoriiformes are related to holocephalans, whereas the other Paleozoic shark-like chondrichthyans are related to neoselachians; 3. many Paleozoic shark-like chondrichthyans, such as the Symmoriiformes, are stem chondrichthyans, whereas stem and crown holocephalans are sister group to the stem and crown neoselachians in a crown-chondrichthyan clade. This third hypothesis was proposed recently, based mainly on dental characters. Methodology/Principal Findings On the basis of two well preserved chondrichthyan neurocrania from the Late Carboniferous of Kansas, USA, we describe here a new species of Symmoriiformes, Kawichthys moodiei gen. et sp. nov., which was investigated by means of computerized X-ray synchrotron microtomography. We present a new phylogenetic analysis based on neurocranial characters, which supports the third hypothesis and corroborates the hypothesis that crown-group chondrichthyans (Holocephali+Neoselachii) form a tightly-knit group within the chondrichthyan total group, by providing additional, non dental characters. Conclusions/Significance Our results highlight the importance of new well preserved Paleozoic fossils and new techniques of observation, and suggest that a new look at the synapomorphies of the crown-group chondrichthyans would be worthwhile in terms of understanding the adaptive significance of phylogenetically important characters.", "keyphrases": ["late carboniferous", "chondrichthyan", "phylogenetic hypothesis"]}
{"id": "10.1080/02724634.2015.1037884", "title": "A New Eocene Toxodontia (Mammalia, Notoungulata) from Northwestern Argentina", "abstract": "ABSTRACT \n A new species of Toxodontia (Mammalia, Notoungulata), Pampahippus secundus sp. nov., is described based on remains recovered from outcrops of the Lumbrera Formation exposed in Salta Province, northwest Argentina. The material studied consists of mandibular, maxillary, and premaxillary fragments with complete and incomplete teeth representing at least three individuals. It differs from the type species P. arenalesi by its smaller size and the presence of several dental features: I2 smaller than the I1 and I3, paraconule absent on the P3, upper molars wider than long and subquadrangular, with a single crista projecting from the ectoloph, strong mesiolingual cingulum surrounding the protocone on the M1, conspicuous metacone fold on the ectoloph of M1 and M2, and absence of labial cingulids on lower molars. In order to determine the phylogenetic position of P. secundus as well as different Paleogene notoungulates of northwestern Argentina, we performed a cladistic analysis. This analysis supports the paraphyly of Notohippidae proposed by previous authors and validates the monophyly of the genus Pampahippus, which ranks as a relatively basal taxon within Toxodontia. This contribution illustrates the significant and yet poorly known diversity of Paleogene toxodontians from northwestern Argentina and the importance of their study in the reconstruction of the evolutionary history of Notoungulata.", "keyphrases": ["toxodontia", "mammalia", "notoungulata", "northwestern argentina"]}
{"id": "paleo.011613", "title": "Endogenous Viral Elements in Animal Genomes", "abstract": "Integration into the nuclear genome of germ line cells can lead to vertical inheritance of retroviral genes as host alleles. For other viruses, germ line integration has only rarely been documented. Nonetheless, we identified endogenous viral elements (EVEs) derived from ten non-retroviral families by systematic in silico screening of animal genomes, including the first endogenous representatives of double-stranded RNA, reverse-transcribing DNA, and segmented RNA viruses, and the first endogenous DNA viruses in mammalian genomes. Phylogenetic and genomic analysis of EVEs across multiple host species revealed novel information about the origin and evolution of diverse virus groups. Furthermore, several of the elements identified here encode intact open reading frames or are expressed as mRNA. For one element in the primate lineage, we provide statistically robust evidence for exaptation. Our findings establish that genetic material derived from all known viral genome types and replication strategies can enter the animal germ line, greatly broadening the scope of paleovirological studies and indicating a more significant evolutionary role for gene flow from virus to animal genomes than has previously been recognized.", "keyphrases": ["animal genome", "integration", "eve", "endogenous viral element"]}
{"id": "paleo.003059", "title": "The taphonomy of colour in fossil insects and feathers", "abstract": "Colouration is an important multifunctional attribute of modern animals, but its evolutionary history is poorly resolved, in part because of our limited ability to recognize and interpret fossil evidence of colour. Recent studies on structural and pigmentary colours in fossil insects and feathers have illuminated important aspects of the anatomy, taphonomy, evolution and function of colour in these fossils. An understanding of the taphonomic factors that control the preservation of colour is key to assessing the fidelity with which original colours are preserved and can constrain interpretations of the visual appearance of fossil insects and theropods. Various analytical approaches can identify anatomical and chemical evidence of colour in fossils; experimental taphonomic studies inform on how colour alters during diagenesis. Preservation of colour is controlled by a suite of factors, the most important of which relate to the diagenetic history of the host sediment, that is, maximum burial temperatures and fluid flow, and subsurface weathering. Future studies focussing on key morphological and chemical aspects of colour preservation relating to cuticular pigments in insects and keratinous structures and nonmelanin pigments in feathers, for example, will resolve outstanding questions regarding the taphonomy of colour and will enhance our ability to infer original colouration and its functions in fossil insects and theropods.", "keyphrases": ["taphonomy", "fossil insect", "feather"]}
{"id": "10.1890/070160", "title": "Paleoecology meets genetics: deciphering past vegetational dynamics", "abstract": "Abstract Genetic analysis adds a novel dimension to paleoecology that is becoming increasingly important for elucidating vegetational dynamics in relation to climate change. Because past vegetational changes have often left distinct genetic imprints on current plant populations, genetic analysis can add detail to fossil-based reconstructions. Recent surveys of DNA polymorphisms yield new insights into past vegetational changes and address long-standing paleoecological questions. These studies reveal that small tree populations survived in mid- to high-latitude refugia throughout the Quaternary glacial episodes. They further reveal migration pathways and demographic processes during postglacial range expansion. These results challenge previous notions regarding tree species responses to climate change and help to identify genetic conservation targets. Here, we review these recent advances and outline research prospects at the interface between paleoecology and genetics.", "keyphrases": ["genetic", "vegetational dynamic", "paleoecology"]}
{"id": "10.1017/S0016756812000428", "title": "First record of Mesozoic terrestrial vertebrates from Lithuania: phytosaurs (Diapsida: Archosauriformes) of probable Late Triassic age, with a review of phytosaur biogeography", "abstract": "Abstract Fossils of Mesozoic terrestrial vertebrates from Lithuania and the wider East Baltic region of Europe have previously been unknown. We here report the first Mesozoic terrestrial vertebrate fossils from Lithuania: two premaxillary specimens and three teeth that belong to Phytosauria, a common clade of semiaquatic Triassic archosauriforms. These specimens represent an uncrested phytosaur, similar to several species within the genera Paleorhinus, Parasuchus, Rutiodon and Nicrosaurus. Because phytosaurs are currently only known from the Upper Triassic, their discovery in northwestern Lithuania (the \u0160alti\u0161kiai clay-pit) suggests that at least part of the Triassic succession in this region is Late Triassic in age, and is not solely Early Triassic as has been previously considered. The new specimens are among the most northerly occurrences of phytosaurs in the Late Triassic, as Lithuania was approximately 7\u201310\u00b0 further north than classic phytosaur-bearing localities in nearby Germany and Poland, and as much as 40\u00b0 further north than the best-sampled phytosaur localities in North America. The far northerly occurrence of the Lithuanian fossils prompts a review of phytosaur biogeography and distribution, which suggests that these predators were widely distributed in the Triassic monsoonal belt but rarer in more arid regions.", "keyphrases": ["terrestrial vertebrate", "lithuania", "phytosaur biogeography"]}
{"id": "10.1017/S0022336000023283", "title": "Long expected sponges from the Neoproterozoic Ediacara fauna of South Australia", "abstract": "New fossils from the Neoproterozoic Ediacara fauna of South Australia are interpreted as the oldest known hexactinellid sponges. They occur within the Ediacara Member of the Rawnsley Quartzite (Pound Subgroup) from several locations in the Flinders Ranges. The new genus, Palaeophragmodictya, is characterized by disc-shaped impressions preserving characteristic spicular networks and is reconstructed as a convex sponge with a peripheral frill and an oscular disc at the apex.", "keyphrases": ["sponge", "neoproterozoic ediacara fauna", "south australia"]}
{"id": "10.1126/sciadv.abb0618", "title": "Quantifying ecospace utilization and ecosystem engineering during the early Phanerozoic\u2014The role of bioturbation and bioerosion", "abstract": "Biogenic reworking played a major role in early Paleozoic oceans, and its study helps to constrain paleo-oxygenation models. The Cambrian explosion (CE) and the great Ordovician biodiversification event (GOBE) are the two most important radiations in Paleozoic oceans. We quantify the role of bioturbation and bioerosion in ecospace utilization and ecosystem engineering using information from 1367 stratigraphic units. An increase in all diversity metrics is demonstrated for the Ediacaran-Cambrian transition, followed by a decrease in most values during the middle to late Cambrian, and by a more modest increase during the Ordovician. A marked increase in ichnodiversity and ichnodisparity of bioturbation is shown during the CE and of bioerosion during the GOBE. Innovations took place first in offshore settings and later expanded into marginal-marine, nearshore, deep-water, and carbonate environments. This study highlights the importance of the CE, despite its Ediacaran roots. Differences in infaunalization in offshore and shelf paleoenvironments favor the hypothesis of early Cambrian wedge-shaped oxygen minimum zones instead of a horizontally stratified ocean.", "keyphrases": ["ecospace utilization", "ecosystem engineering", "bioturbation"]}
{"id": "paleo.003354", "title": "Earliest known lepisosteoid extends the range of anatomically modern gars to the Late Jurassic", "abstract": "Lepisosteoids are known for their evolutionary conservatism, and their body plan can be traced at least as far back as the Early Cretaceous, by which point two families had diverged: Lepisosteidae, known since the Late Cretaceous and including all living species and various fossils from all continents, except Antarctica and Australia, and Obaichthyidae, restricted to the Cretaceous of northeastern Brazil and Morocco. Until now, the oldest known lepisosteoids were the obaichthyids, which show general neopterygian features lost or transformed in lepisosteids. Here we describe the earliest known lepisosteoid (Nhanulepisosteus mexicanus gen. and sp. nov.) from the Upper Jurassic (Kimmeridgian \u2013 about 157 Myr), of the Tlaxiaco Basin, Mexico. The new taxon is based on disarticulated cranial pieces, preserved three-dimensionally, as well as on scales. Nhanulepisosteus is recovered as the sister taxon of the rest of the Lepisosteidae. This extends the chronological range of lepisosteoids by about 46 Myr and of the lepisosteids by about 57 Myr, and fills a major morphological gap in current understanding the early diversification of this group.", "keyphrases": ["gar", "late jurassic", "lepisosteidae"]}
{"id": "10.1080/02724634.2012.711404", "title": "A New Eocene Locality in Southern France Sheds Light on the Basal Radiation of Palaeotheriidae (Mammalia, Perissodactyla, Equoidea)", "abstract": "ABSTRACT \n A new Eocene locality in southern France has yielded a poorly diversified vertebrate fauna but does contain abundant material representing a new species of early equoid, Pachynolophus eulaliensis, sp. nov. Biostratigraphic data for this new locality of Sainte-Eulalie suggest a middle Ypresian age. The new species is the oldest representative of the Palacotheriidae, here including the controversial pachynolophs. The abundant remains of this taxon from a single locality allow the recognition of a high degree of unsuspected variability within this taxon, including sexual dimorphism, thus permitting discussion of the reliability of commonly used characters. A phylogenetic analysis led us to emend the diagnosis of the genus Pachynolophus as well as to suggest the exclusion of \u2018Pachynolophus\u2019 hookeri from the genus. This study proposes new hypotheses of relationships among the basal Equoidea and allows us to distinguish the two main groups (Equidae and Palaeotheriidae) earlier in the Eocene, close to the reference level MP8\u20139. The new material appears to be a fundamental cornerstone in solving the question of the controversial systematics and phylogeny of pachynolophs. It also sheds new light on the temporal and spatial distribution of the initial radiation of European equoids.", "keyphrases": ["new eocene locality", "southern france", "palaeotheriidae"]}
{"id": "paleo.000306", "title": "Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger", "abstract": "We report the discovery of basal abelisaurid and carcharodontosaurid theropods from the mid Cretaceous (Aptian-Albian, ca. 112 Ma) Elrhaz Formation of the Niger Republic. The abelisaurid, Kryptops palaios gen. et sp. nov., is represented by a single individual preserving the maxilla, pelvic girdle, vertebrae and ribs. Several features, including a maxilla textured externally by impressed vascular grooves and a narrow antorbital fossa, clearly place Kryptops palaios within Abelisauridae as its oldest known member. The carcharodontosaurid, Eocarcharia dinops gen. et sp. nov., is represented by several cranial bones and isolated teeth. Phylogenetic analysis places it as a basal carcharodontosaurid, similar to Acrocanthosaurus and less derived than Carcharodontosaurus and Giganotosaurus. The discovery of these taxa suggests that large body size and many of the derived cranial features of abelisaurids and carcharodontosaurids had already evolved by the mid Cretaceous. The presence of a close relative of the North American genus Acrocanthosaurus on Africa suggests that carcharodontosaurids had already achieved a trans-Tethyan distribution by the mid Cretaceous.", "keyphrases": ["theropod", "eocarcharia", "cranial bone", "basal abelisaurid"]}
{"id": "10.1029/2017PA003306", "title": "Global Extent of Early Eocene Hyperthermal Events: A New Pacific Benthic Foraminiferal Isotope Record From Shatsky Rise (ODP Site 1209)", "abstract": "Studying the dynamics of past global warming events during the late Paleocene to middle Eocene informs our understanding of Earth's carbon cycle behavior under elevated atmospheric pCO2 conditions. Due to sparse data coverage, the spatial character of numerous hyperthermal events during this period is still poorly constrained. Here we present a high\u2010resolution, benthic foraminiferal stable isotope record for northwest Pacific ODP Site 1209 (Leg 198) spanning 44 to 56 Ma with 5 kyr resolution. An existing Paleocene section was extended into the middle Eocene creating an unprecedented 22 Myr single\u2010site record. Several identified carbon isotope excursions correspond in timing and magnitude to hyperthermal layers previously described elsewhere. Maxima in scanning X\u2010ray fluorescence Fe intensities and pronounced minima in the wt% coarse fraction characterize carbonate dissolution for all of the hyperthermal events. The new astronomically calibrated stable oxygen isotope record assists in defining the onset, duration, and demise of the Early Eocene Climate Optimum (EECO, 49.14 to 53.26 Ma) and the onset of global cooling after the EECO (49.14 Ma). The cooling trend was interrupted by two warming episodes at 47.2 and 46.7 Ma. A major positive shift in the benthic foraminiferal carbon isotope record occurring from 51.2 to 51.0 Ma is now confirmed to be global. Benthic foraminiferal \u03b413C records from Atlantic and Pacific Oceans converge from 52.0 to 47.5 Ma pointing to a closer connection of deepwater convection initiating well in advance of the final connection ~40 Ma ago or an increase in bottom water formation around Antarctica.", "keyphrases": ["hyperthermal event", "paleocene", "cenozoic"]}
{"id": "paleo.000137", "title": "Lochkovian Conodonts from Podolia, Ukraine, and their Stratigraphic Significance", "abstract": "In the Podolian Dniester Basin (southwestern Ukraine) the Lower Devonian marine deposits are represented by about 530 m thick continuous sequence of interlaminated carbonate and schale outcrops at several localities. Conodonts occur in most of the carbonate layers of the whole Lochkovian but are not abundant and their ramiform elements are mostly broken or lacking. Therefore, only the pectiniform, Pa elements of twenty five stratigraphically important conodont species occurring in the region are discussed and two new species, Caudicriodus schoenlaubi and Pandorinellina? parva are proposed. The hypothetical phyletic relationships within the main representatives of the icriodontid and spathognathodontid genera, Caudicriodus, Zieglerodina, and Pandorinellina? are traced. Comparison of the previously published and newly obtained data revealed discrepancies in the hitherto used interpretation of some of the conodont taxa and their stratigraphic ranges. Contrary to the earlier reports, Caudicriodus postwoschmidti does not occur in the lower Lochkovian but only in the middle part of the Chortkiv Formation, high above the Munograptus uniformis Zone. Based on new material and verification of the previous determinations, a modified scheme of the Lochkovian conodont zonation in Podolia is proposed. Conodont zones: Caudicriudus hesperius, C. transiens, C. postwoschmidti, C. serus, and ?Caudicriodus steinachensis are distinguished. The zones are correlated with conodont zonations in other regions\u2014Barrandian, Cantabrian Mountains, Pyrenees, and Nevada. Biostratigraphy of the Siluro-Devonian transition and Lochkovian is integrated with the carbon isotope stratigraphy.", "keyphrases": ["conodont", "podolia", "devonian marine deposit", "argillaceous shale"]}
{"id": "10.1144/SP379.21", "title": "Anatomy, phylogeny and palaeobiology of early archosaurs and their kin", "abstract": "Archosaurs, an important reptile group that includes today\u2019s crocodiles and birds, arose during the Triassic in the aftermath of the greatest mass extinction of all time. In the last 20 years, our understanding of the early evolution of the group has improved substantially with the discovery of new fossils and species of early archosaurs and their closest relatives, a better understanding of the relationships of these animals, and new insights into their palaeobiology. In order to synthesize these new data, researchers of early archosaurs from around the world met at the first symposium of early archosaur evolution at the IV Congreso Latinoamericano de Paleontologia de Vertebrados (September 2011) in San Juan, Argentina. This symposium facilitated collaboration and strove to paint a better understanding of these extraordinary animals. The resultant body of work is a state-of-the-art examination of early archosaur groups and their close relatives including historical, anatomical, biogeographical, evolutionary and palaeobiological data. This contribution furthers our knowledge of the anatomy, relationships, and palaeobiology of species-level taxa as well as more global patterns of archosaur evolution during the Triassic.", "keyphrases": ["palaeobiology", "early archosaur", "anatomy"]}
{"id": "10.1002/jmor.20288", "title": "Developmental changes in the skull morphology of common minke whales Balaenoptera acutorostrata", "abstract": "We investigated growth\u2010related and sex\u2010related morphological changes in the skulls of 144 North Pacific common minke whales Balaenoptera acutorostrata. Measurement was conducted at 39 points on the skull and mandible to extract individual allometric equations relating the length and zygomatic width of the skull. The results revealed no significant differences in skull morphology by sex except for width of occipital bone. The size relative to the skull of the anatomical parts involved in feeding, such as the rostrum and mandible, increased after birth. In contrast, the sensory organs and the anatomical regions involved in neurological function, such as the orbit, tympanic bullae, and foramen magnum, were fully developed at birth, and their relative size reduced over the course of development. This is the first study to investigate developmental changes in the skull morphology using more than 100 baleen whale specimens, and we believe the results of this study will contribute greatly to multiple areas of baleen whale research, including taxonomy and paleontology. J. Morphol. 275:1113\u20131121, 2014. \u00a9 2014 Wiley Periodicals, Inc.", "keyphrases": ["skull morphology", "whale balaenoptera acutorostrata", "developmental change"]}
{"id": "10.4236/ns.2013.511148", "title": "Evolution of white and megatooth sharks, and evidence for early predation on seals, sirenians, and whales", "abstract": "The early white shark Carcharodon Smith, 1838 with the fossil Carcharodon auriculatus (Blainville, 1818) and \nthe extinct megatooth shark Otodus Agassiz, 1843 with species Otodus sokolovi (Jaeckel, 1895) were both present in the European proto North Sea Basin about 47.8 - 41.3 m.y. ago (Lutetian, \nearly Middle Eocene), as well as in the Tethys realm around the Afican-Eurasian shallow marine habitats. Both top predators \ndeveloped to be polyphyletic, with possible two different lamnid \nshark ancestors within the Early Paleocene to Early Eocene timespan with Carcharodon (white shark line-age) and Otodus (megatooth shark lineage). Their \nsawblade teeth developed during the early Paleogene as the result of adaptation \nto feeding on various marine new rising mammals, coinciding with three main \nwaves of evolutionary emergence of seals, sirenians, and whales in parallel with \nthe evolution of these large predatory sharks. Megatooth sharks specialized in \nhunting whales and sirenians only on the coastal shelves of warm oceans and \ndisappeared globally in the Pleistocene due to climate change and ocean cooling. \nThe cold-water adapted early white sharks have survived until the present day \nwith body temperate change adaptation in warm to temperate oceans and are \nproposed to have specialized on coastal seal hunting already50 m.y. ago.", "keyphrases": ["megatooth shark", "seal", "whale"]}
{"id": "10.1002/ajpa.10024", "title": "Paleohistopathology of bone: a new approach to the study of ancient diseases.", "abstract": "Light microscopy, particularly the use of polarized light, has such a high value for the differential diagnosis of dry bones that it can no longer be neglected. Alterations caused intra vitam by disease or other living conditions can clearly be differentiated by this technique from changes due to postmortem reactions (e.g., pseudopathology). As a reliable diagnosis is the basis not only of the study of case reports but also of the etiology and epidemiology of diseases in ancient populations, paleopathologists would be well-advised to employ histological analysis for their research, to avoid false diagnoses. The necessary basis for such research is the knowledge of the general histology, histogenesis, and growth as well as pathophysiology of bone. Some new techniques which facilitate the practical use of microscopic analysis, such as the preparation of thin-ground sections from undecalcified bone samples and nonrehydrated mummified soft tissues, are described. Selected examples of mechanisms of pathological bone changes, particularly the determination of vestiges of diseases in macerated bones by microscopy, are presented. Emphasis is placed on the differential diagnoses of proliferative reactions (e.g., periosteal processes of long bones and the skull). In this context, the importance of meningeal reactions on the endocranial lamina of the skull for morbidity and mortality in ancient populations is demonstrated. Furthermore, porotic hyperostosis of the skull vault and the orbital roof, i.e., the cribra cranii externa and cribra orbitalia, is discussed. Selected examples of the etiology and epidemiology of ancient diseases are presented (e.g., anemia, scurvy, rickets, and meningeal diseases), and ideas on living conditions and their implications for the origin and the spread of disease are given to establish a better understanding of deficiency and infectious diseases in the past.", "keyphrases": ["disease", "vestige", "skull"]}
{"id": "paleo.004777", "title": "Changhsingian brachiopod communities along a marine depth gradient in South China and their ecological significance in the end\u2010Permian mass extinction", "abstract": "Diversity indices (dominance and evenness) and ecological spatial structure (lifestyles and relative abundances) are important features of Changhsingian brachiopod communities prior to the end-Permian mass extinction (EPME) and could predict temporal and spatial extinction patterns during the EPME. In South China, Changhsingian brachiopod communities show higher diversity than other contemporaneous brachiopod communities in the world and have been reported from a variety of sedimentary environments. In this paper, brachiopods from 18 sections in South China were selected to divide communities and compare their ecological structure. Based on the results of network analysis, cluster analysis and quantitative data from the selected sections, we show that Changhsingian brachiopod communities in South China can be categorized into three assemblages along a marine depth gradient: the Neochonetes-Fusichonetes-Paryphella Assemblage from the shallowwater clastic-rock facies, Spinomarginifera-Peltichia-Oldhamina Assemblage from the shallow-water carbonate platform facies and Fusichonetes-Crurithyris Assemblage from the deep-water siliciclastic intracontinental basin facies. Compared with communities from carbonate platform facies, the communities from siliciclastic facies were characterized by high dominance, low evenness and low lifestyle diversity, which might be important biotic factors leading to earlier extinctions. After the extinction began in all environments, the whole earliest Triassic brachiopod community was first dominated by Fusichonetes and then by Crurithyris. These patterns of domination and replacement could be explained by morphological and ecological advantages. The domination of these two genera, which were already adapted to the oxygen and food-limited deep-water habitat, indicates that the cooler deep-water environment might have been a relatively less stressed habitat after the beginning of the EPME. This suggests that global warming might be the main trigger among the previously proposed synergistic environmental stresses, while anoxia might not, at least for the beginning of EPME. \u25a1 Cluster analysis, dominant taxa, ecological structure, extinction, network analysis, selectivity.", "keyphrases": ["marine depth gradient", "south china", "fusichonetes", "changhsingian brachiopod community"]}
{"id": "paleo.007481", "title": "CLADISTIC ANALYSIS OF THE SUBORDER CONULARIINA MILLER AND GURLEY, 1896 (CNIDARIA, SCYPHOZOA; VENDIAN\u2013TRIASSIC)", "abstract": "Abstract:\u2002 Results of a cladistic analysis of the suborder Conulariina Miller and Gurley, 1896, a major extinct (Vendian\u2013Triassic) group of scyphozoan cnidarians, are presented. The analysis sought to test whether the three conulariid subfamilies (Conulariinae Walcott, 1886 , Paraconulariinae Sinclair, 1952 and Ctenoconulariinae Sinclair, 1952 ) recognized in the Treatise on Invertebrate Paleontology (TIP) are monophyletic. A total of 17 morphological characters were scored for 16 ingroup taxa, namely the genera Archaeoconularia, Baccaconularia, Climacoconus, Conularia, Conulariella, Conularina, Ctenoconularia, Eoconularia, Glyptoconularia, Metaconularia, Notoconularia, Paraconularia, Pseudoconularia, Reticulaconularia, Teresconularia and Vendoconularia. The extant medusozoan taxa Cubozoa, Stauromedusae, Coronatae and Semaeostomeae served as outgroups. Unweighted analysisof the data matrix yielded 1057 trees, and successive weighting analysis resulted in one of the 1057 original trees. The ingroup is monophyletic with two autapomorphies: (1) the quadrate geometry of the oral region; and (2) the presence of a mineralized (phosphatic) periderm. Within the ingroup, the clade (Vendoconularia, Teresconularia, Conularina, Eoconularia) is supported by the sinusoidal longitudinal geometry of the transverse ridges, and the much larger clade (Baccaconularia, Glyptoconularia, Metaconularia, Pseudoconularia, Conularia, Ctenoconularia, Archaeoconularia, Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the presence of external tubercles, which, however, were lost in the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia). As proposed by Van Iten et al. (2000) , the clade (Notoconularia, Climacoconus, Paraconularia, Reticulaconularia) is supported by the termination and alternation of the transverse ribs in the corner sulcus. The previously recognized subfamilies Conulariinae, Paraconulariinae and Ctenoconulariinae were not recovered from this analysis. The diagnostic features of Conulariinae (continuation of the transverse ornament across the corner sulcus and lack of carinae) and Ctenoconulariinae (presence of carinae) are symplesiomorphic or homoplastic, and Paraconulariinae is polyphyletic. The families Conulariellidae Kiderlen, 1937 and Conulariopsidae Sugiyama, 1942 , also recognized in the TIP, are monogeneric, and since they provide no additional phylogenetic information, should be abandoned.", "keyphrases": ["suborder conulariina miller", "cnidaria", "scyphozoa"]}
{"id": "paleo.009382", "title": "Supernovae, Neutrinos and the Chirality of Amino Acids", "abstract": "A mechanism for creating an enantioenrichment in the amino acids, the building blocks of the proteins, that involves global selection of one handedness by interactions between the amino acids and neutrinos from core-collapse supernovae is defined. The chiral selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the 14N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. It also requires an asymmetric distribution of neutrinos emitted from the supernova. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth\u2019s proteinaceous amino acids.", "keyphrases": ["chirality", "amino acid", "supernovae"]}
{"id": "paleo.012220", "title": "Wrist morphology reveals substantial locomotor diversity among early catarrhines: an analysis of capitates from the early Miocene of Tinderet (Kenya)", "abstract": "Considerable taxonomic diversity has been recognised among early Miocene catarrhines (apes, Old World monkeys, and their extinct relatives). However, locomotor diversity within this group has eluded characterization, bolstering a narrative that nearly all early catarrhines shared a primitive locomotor repertoire resembling that of the well-described arboreal quadruped Ekembo heseloni. Here we describe and analyse seven catarrhine capitates from the Tinderet Miocene sequence of Kenya, dated to ~20 Ma. 3D morphometrics derived from these specimens and a sample of extant and fossil capitates are subjected to a series of multivariate comparisons, with results suggesting a variety of locomotor repertoires were present in this early Miocene setting. One of the fossil specimens is uniquely derived among early and middle Miocene capitates, representing the earliest known instance of great ape-like wrist morphology and supporting the presence of a behaviourally advanced ape at Songhor. We suggest Rangwapithecus as this catarrhine\u2019s identity, and posit expression of derived, ape-like features as a criterion for distinguishing this taxon from Proconsul africanus. We also introduce a procedure for quantitative estimation of locomotor diversity and find the Tinderet sample to equal or exceed large extant catarrhine groups in this metric, demonstrating greater functional diversity among early catarrhines than previously recognised.", "keyphrases": ["locomotor diversity", "early catarrhine", "wrist morphology"]}
{"id": "paleo.011558", "title": "Palaeoproteomics gives new insight into early southern African pastoralism", "abstract": "The advent of domestication is a major step that transformed the subsistence strategies of past human societies. In Africa, domestic caprines (sheep and goat) were introduced in the north-eastern part of the continent from the Near East more than 9000 years ago. However, their diffusion southwards was slow. They are thought to have made their first appearance in the southern part of the continent ca. 2000 years ago, at a few Later Stone Age sites, including Leopard Cave (Erongo region, Namibia), which provided the oldest directly dated remains assigned to sheep or goat on the basis of morphology of bones and teeth. However, similarities in morphology, not only between these two domesticated caprine species, but also between them and the small wild antelopes, raised questions about the morphological species attribution of these remains. Additionally, the high fragmentation of the site\u2019s osteological remains makes it difficult to achieve species-level taxonomic identification by comparative anatomy. In this paper, we report molecular species identification of the Leopard Cave remains using palaeoproteomics, a method that uses protein markers in bone and tooth collagen to achieve taxonomic identification of archaeological remains. We also report new direct radiocarbon dates. Wild antelope remains from museum collections were used to enrich the available protein record and propose de novo type I collagen sequences. Our results demonstrate that the remains morphologically described as domesticates actually belong to a wild antelope species and that domestic caprines first appeared at Leopard Cave 1500 years later than previously thought. This study illustrates that the use of palaeoproteomics coupled with direct radiocarbon dates is particularly suited to complement classic zooarchaeological studies, in this case concerning the arrival of the first herding practices in arid environments.", "keyphrases": ["caprine", "leopard cave", "namibia", "palaeoproteomic", "zooms"]}
{"id": "10.1093/molbev/msj124", "title": "Early penguin fossils, plus mitochondrial genomes, calibrate avian evolution.", "abstract": "Testing models of macroevolution, and especially the sufficiency of microevolutionary processes, requires good collaboration between molecular biologists and paleontologists. We report such a test for events around the Late Cretaceous by describing the earliest penguin fossils, analyzing complete mitochondrial genomes from an albatross, a petrel, and a loon, and describe the gradual decline of pterosaurs at the same time modern birds radiate. The penguin fossils comprise four naturally associated skeletons from the New Zealand Waipara Greensand, a Paleocene (early Tertiary) formation just above a well-known Cretaceous/Tertiary boundary site. The fossils, in a new genus (Waimanu), provide a lower estimate of 61-62 Ma for the divergence between penguins and other birds and thus establish a reliable calibration point for avian evolution. Combining fossil calibration points, DNA sequences, maximum likelihood, and Bayesian analysis, the penguin calibrations imply a radiation of modern (crown group) birds in the Late Cretaceous. This includes a conservative estimate that modern sea and shorebird lineages diverged at least by the Late Cretaceous about 74 +/- 3 Ma (Campanian). It is clear that modern birds from at least the latest Cretaceous lived at the same time as archaic birds including Hesperornis, Ichthyornis, and the diverse Enantiornithiformes. Pterosaurs, which also coexisted with early crown birds, show notable changes through the Late Cretaceous. There was a decrease in taxonomic diversity, and small- to medium-sized species disappeared well before the end of the Cretaceous. A simple reading of the fossil record might suggest competitive interactions with birds, but much more needs to be understood about pterosaur life histories. Additional fossils and molecular data are still required to help understand the role of biotic interactions in the evolution of Late Cretaceous birds and thus to test that the mechanisms of microevolution are sufficient to explain macroevolution.", "keyphrases": ["mitochondrial genome", "avian evolution", "new zealand", "paleocene", "early penguin fossil"]}
{"id": "10.1111/j.1469-185X.2006.tb00215.x", "title": "Bird evolution in the Eocene: climate change in Europe and a Danish fossil fauna", "abstract": "The pattern of the evolutionary radiation of modern birds (Neornithes) has been debated for more than 10 years. However, the early fossil record of birds from the Paleogene, in particular, the Lower Eocene, has only recently begun to be used in a phylogenetic context to address the dynamics of this major vertebrate radiation. The Cretaceous\u2010Paleogene (K\u2010P) extinction event dominates our understanding of early modern bird evolution, but climate change throughout the Eocene is known to have also played a major role. The Paleocene and Lower Eocene was a time of avian diversification as a result of favourable global climatic conditions. Deteriorations in climate beginning in the Middle Eocene appear to be responsible for the demise of previously widespread avian lineages like Lithornithiformes and Gastornithidae. Other groups, such as Galliformes display replacement of some lineages by others, probably related to adaptations to a drier climate. Finally, the combination of slowly deteriorating climatic conditions from the Middle Eocene onwards, appears to have slowed the evolutionary rate in Europe, as avian faunas did not differentiate markedly until the Oligocene. Taking biotic factors in tandem with the known Paleogene fossil record of Neornithes has recently begun to illuminate this evolutionary event. Well\u2010preserved fossil taxa are required in combination with ever\u2010improving phylogenetic hypotheses for the interrelationships of modern birds founded on morphological characters. One key avifauna of this age, synthesised for the first time herein, is the Lower Eocene Fur Formation of Denmark. The Fur birds represent some of the best preserved (often in three dimensions and with soft tissues) known fossil records for major clades of modern birds. Clear phylogenetic assessment of these fossils will prove critical for future calibration of the neornithine evolutionary timescale. Some early diverging clades were clearly present in the Paleocene as evidenced directly by new fossil material alongside the phylogenetically constrained Lower Eocene taxa. A later Oligocene radiation of clades other than Passeriformes is not supported by available fossil data.", "keyphrases": ["eocene", "climate change", "bird evolution"]}
{"id": "10.1017/pab.2019.42", "title": "The Burgess Shale paleocommunity with new insights from Marble Canyon, British Columbia", "abstract": "Abstract. The middle (Wuliuan Stage) Cambrian Burgess Shale is famous for its exceptional preservation of diverse and abundant soft-bodied animals through the \u201cthick\u201d Stephen Formation. However, with the exception of the Walcott Quarry (Fossil Ridge) and the stratigraphically older Tulip Beds (Mount Stephen), which are both in Yoho National Park (British Columbia), quantitative assessments of the Burgess Shale have remained limited. Here we first provide a detailed quantitative overview of the diversity and structure of the Marble Canyon Burgess Shale locality based on 16,438 specimens. Located 40 km southeast of the Walcott Quarry in Kootenay National Park (British Columbia), Marble Canyon represents the youngest site of the \u201cthick\u201d Stephen Formation. We then combine paleoecological data sets from Marble Canyon, Walcott Quarry, Tulip Beds, and Raymond Quarry, which lies approximately 20 m directly above the Walcott Quarry, to yield a combined species abundance data set of 77,179 specimens encompassing 234 species-level taxa. Marble Canyon shows significant temporal changes in both taxonomic and ecological groups, suggesting periods of stasis followed by rapid turnover patterns at local and short temporal scales. At wider geographic and temporal scales, the different Burgess Shale sites occupy distinct areas in multivariate space. Overall, this suggests that the Burgess Shale paleocommunity is far patchier than previously thought and varies at both local and regional scales through the \u201cthick\u201d Stephen Formation. This underscores that our understanding of Cambrian diversity and ecological networks, particularly in early animal ecosystems, remains limited and highly dependent on new discoveries.", "keyphrases": ["burgess shale paleocommunity", "marble canyon", "british columbia"]}
{"id": "10.1111/let.12011", "title": "The snout of Cricosaurus araucanensis: a case study in novel anatomy of the nasal region of metriorhynchids", "abstract": "Metriorhynchids are the only crocodyliforms adapted to pelagic marine life. Snout natural endocasts of the Tithonian (Late Jurassic) metriorhynchid Cricosaurus araucanensis indicated that skeletal changes defining the peculiar metriorhynchid body plan were coupled with changes of the soft cephalic anatomy such as the enlarged salt glands and restructuring of the paranasal sinus system. Seven new natural endocasts of the snout and a 3-D reconstruction of C.\u00a0araucanensis are described. Data from these casts and the reconstruction are congruent, and they are combined into an accurate reconstruction that improves our knowledge of the pre-orbital anatomy. The olfactory tract, bulbs, olfactory nasal region and the anterior extension of the antorbital sinus within the maxilla are recognized. Osteological correlates of the salt gland body are also proposed. Palaeobiological inferences are erected based on the integration of natural endocasts and 3-D reconstruction data. It is proposed that C.\u00a0araucanensis nasal salt glands were highly vascularized with a blood supply comparable with those of extant marine birds. Reduced olfactory bulbs and olfactory nasal region indicate that the aerial olfaction, differing from extant crocodilians, was not well developed.", "keyphrases": ["cricosaurus araucanensis", "nasal region", "metriorhynchid"]}
{"id": "paleo.000920", "title": "The Fossil Record of Early Tetrapods: Worker Effort and the End-Permian Mass Extinction", "abstract": "It is important to understand the quality of the fossil record of early tetrapods (Tetrapoda, minus Lissamphibia and Amniota) because of their key role in the transition of vertebrates from water to land, their dominance of terrestrial faunas for over 100 million years of the late Palaeozoic and early Mesozoic, and their variable fates during the end-Permian mass extinction. The first description of an early tetrapod dates back to 1824, and since then discoveries have occurred at a rather irregular pace, with peaks and troughs corresponding to some of the vicissitudes of human history through the past two centuries. As expected, the record is dominated by the well-sampled sedimentary basins of Europe and North America, but finds from other continents are increasing rapidly. Comparisons of snapshots of knowledge in 1900, 1950, and 2000 show that discovery of new species has changed the shape of the species-level diversification curve, contrary to earlier studies of family-level taxa. There is, however, little evidence that taxon counts relate to research effort (as counted by numbers of publications), and there are no biasing effects associated with differential study of different time intervals through the late Palaeozoic and Mesozoic. In fact, levels of effort are apparently not related to geological time, with no evidence that workers have spent more time on more recent parts of the record. In particular, the end-Permian mass extinction was investigated to determine whether diversity changes through that interval might reflect worker effort: it turns out that most records of early tetrapod taxa (when corrected for duration of geological series) occur in the Lower Triassic.", "keyphrases": ["early tetrapod", "worker effort", "end-permian mass extinction"]}
{"id": "10.1111/brv.12223", "title": "Combining marine macroecology and palaeoecology in understanding biodiversity: microfossils as a model", "abstract": "There is growing interest in the integration of macroecology and palaeoecology towards a better understanding of past, present, and anticipated future biodiversity dynamics. However, the empirical basis for this integration has thus far been limited. Here we review prospects for a macroecology\u2013palaeoecology integration in biodiversity analyses with a focus on marine microfossils [i.e. small (or small parts of) organisms with high fossilization potential, such as foraminifera, ostracodes, diatoms, radiolaria, coccolithophores, dinoflagellates, and ichthyoliths]. Marine microfossils represent a useful model system for such integrative research because of their high abundance, large spatiotemporal coverage, and good taxonomic and temporal resolution. The microfossil record allows for quantitative cross\u2010scale research designs, which help in answering fundamental questions about marine biodiversity, including the causes behind similarities in patterns of latitudinal and longitudinal variation across taxa, the degree of constancy of observed gradients over time, and the relative importance of hypothesized drivers that may explain past or present biodiversity patterns. The inclusion of a deep\u2010time perspective based on high\u2010resolution microfossil records may be an important step for the further maturation of macroecology. An improved integration of macroecology and palaeoecology would aid in our understanding of the balance of ecological and evolutionary mechanisms that have shaped the biosphere we inhabit today and affect how it may change in the future.", "keyphrases": ["macroecology", "palaeoecology", "biodiversity"]}
{"id": "paleo.000176", "title": "A New Taxon of Basal Ceratopsian from China and the Early Evolution of Ceratopsia", "abstract": "Ceratopsia is one of the best studied herbivorous ornithischian clades, but the early evolution of Ceratopsia, including the placement of Psittacosaurus, is still controversial and unclear. Here, we report a second basal ceratopsian, Hualianceratops wucaiwanensis gen. et sp. nov., from the Upper Jurassic (Oxfordian) Shishugou Formation of the Junggar Basin, northwestern China. This new taxon is characterized by a prominent caudodorsal process on the subtemporal ramus of the jugal, a robust quadrate with an expansive quadratojugal facet, a prominent notch near the ventral region of the quadrate, a deep and short dentary, and strongly rugose texturing on the lateral surface of the dentary. Hualianceratops shares several derived characters with both Psittacosaurus and the basal ceratopsians Yinlong, Chaoyangsaurus, and Xuanhuaceratops. A new comprehensive phylogeny of ceratopsians weakly supports both Yinlong and Hualianceratops as chaoyangsaurids (along with Chaoyangsaurus and Xuanhuaceratops), as well as the monophyly of Chaoyangosauridae + Psittacosaurus. This analysis also weakly supports the novel hypothesis that Chaoyangsauridae + Psittacosaurus is the sister group to the rest of Neoceratopsia, suggesting a basal split between these clades before the Late Jurassic. This phylogeny and the earliest Late Jurassic age of Yinlong and Hualianceratops imply that at least five ceratopsian lineages (Yinlong, Hualianceratops, Chaoyangsaurus + Xuanhuaceratops, Psittacosaurus, Neoceratopsia) were present at the beginning of the Late Jurassic.", "keyphrases": ["new taxon", "basal ceratopsian", "china", "xuanhuaceratops", "neoceratopsia"]}
{"id": "paleo.011414", "title": "Disparate compound eyes of Cambrian radiodonts reveal their developmental growth mode and diverse visual ecology", "abstract": "Fossil eyes show that some early marine arthropods had acute vision and were capable of functioning at different light levels. Radiodonts are nektonic stem-group euarthropods that played various trophic roles in Paleozoic marine ecosystems, but information on their vision is limited. Optical details exist only in one species from the Cambrian Emu Bay Shale of Australia, here assigned to Anomalocaris aff. canadensis. We identify another type of radiodont compound eye from this deposit, belonging to \u2018Anomalocaris\u2019 briggsi. This \u22644-cm sessile eye has >13,000 lenses and a dorsally oriented acute zone. In both taxa, lenses were added marginally and increased in size and number throughout development, as in many crown-group euarthropods. Both species\u2019 eyes conform to their inferred lifestyles: The macrophagous predator A. aff. canadensis has acute stalked eyes (>24,000 lenses each) adapted for hunting in well-lit waters, whereas the suspension-feeding \u2018A.\u2019 briggsi could detect plankton in dim down-welling light. Radiodont eyes further demonstrate the group\u2019s anatomical and ecological diversity and reinforce the crucial role of vision in early animal ecosystems.", "keyphrases": ["compound eye", "radiodont", "ecology", "anomalocaris", "canadensis"]}
{"id": "paleo.011666", "title": "Morphological stasis in the first myxomycete from the Mesozoic, and the likely role of cryptobiosis", "abstract": "Myxomycetes constitute a group within the Amoebozoa well known for their motile plasmodia and morphologically complex fruiting bodies. One obstacle hindering studies of myxomycete evolution is that their fossils are exceedingly rare, so evolutionary analyses of this supposedly ancient lineage of amoebozoans are restricted to extant taxa. Molecular data have significantly advanced myxomycete systematics, but the evolutionary history of individual lineages and their ecological adaptations remain unknown. Here, we report exquisitely preserved myxomycete sporocarps in amber from Myanmar, ca. 100 million years old, one of the few fossil myxomycetes, and the only definitive Mesozoic one. Six densely-arranged stalked sporocarps were engulfed in tree resin while young, with almost the entire spore mass still inside the sporotheca. All morphological features are indistinguishable from those of the modern, cosmopolitan genus Stemonitis, demonstrating that sporocarp morphology has been static since at least the mid-Cretaceous. The ability of myxomycetes to develop into dormant stages, which can last years, may account for the phenotypic stasis between living Stemonitis species and this fossil one, similar to the situation found in other organisms that have cryptobiosis. We also interpret Stemonitis morphological stasis as evidence of strong environmental selection favouring the maintenance of adaptations that promote wind dispersal.", "keyphrases": ["myxomycete", "mesozoic", "morphological stasis"]}
{"id": "10.1080/03115518.2013.764663", "title": "Discovery of an exceptionally preserved fossil assemblage in the Balang Formation (Cambrian Series 2, Stage 4) in Hunan, China", "abstract": "Liu, Q. & Lei, Q.P., 2013. Discovery of an exceptionally preserved fossil assemblage in the Balang Formation (Cambrian Series 2, Stage 4) in Hunan, China. Alcheringa, 1\u20133. ISSN 0311-5518. An exceptionally preserved fossil assemblage of algae, sponges, chancelloriids, cnidarians, worms, molluscs, brachiopods, trilobites and non-mineralized arthropods is documented from the lower part of the Balang Formation (Cambrian Series 2, Stage 4) in Paiwu, northwestern Hunan Province, China. The discovery extends the distribution of Cambrian Burgess Shale-type Lagerst\u00e4tten in China.", "keyphrases": ["fossil assemblage", "balang formation", "algae", "arthropod"]}
{"id": "paleo.005719", "title": "Palaeoecological significance of coral-encrusting foraminiferan associations: A case-study from the Upper Eocene of northern Italy", "abstract": "Encrusting foraminiferans, although representing an important component of the so-called cryptic assemblages in both modern and ancient reef environments, are in general poorly described and little is known as regards their association with corals. In this paper, we describe coral-encrusting foraminiferan associations in the different facies that characterize the shallowing upward parasequences of the Nago Limestone (Upper Eocene, Trentino, northern Italy). From a relatively deep reef slope up to the shallow shelf-edge, corals have been recognized to be encrusted by different types of foraminiferan assemblages that differ on the basis of relative abundance of species, growth form and type of encrusted coral surface. The succession of encrusting foraminiferan assemblages is interpreted as controlled mainly by light, competition with coralline algae, hydrodynamic energy, and coral growth fabric.", "keyphrases": ["coral-encrusting foraminiferan association", "upper eocene", "northern italy"]}
{"id": "paleo.005371", "title": "The Extent of the Pterosaur Flight Membrane", "abstract": "The shape and extent of the membranous brachioptagium in pterosaurs remains a controversial topic for those attempting to determine the aerodynamic performance of the first vertebrate fliers. Various arguments in favour of the trailing edge terminating against either the torso or hip, the femur, the ankle, or different locations for various taxa, has resulted in several published reconstructions. Uncertainty over the correct model is detrimental to both aerodynamic and palaeoecological studies that are forced to simultaneously consider multiple and highly variable configurations for individual taxa. A review of relevant pterosaur specimens with preserved soft tissues or impressions of the wing membrane, however, strongly suggests that the trailing edge of the wing extended down to the lower leg or ankle in all specimens where the brachiopatagium is completely preserved. This configuration is seen across a phylogenetically broad range of pterosaurs and is thus likely to have been universally present throughout the Pterosauria. Support for opposing hypotheses where the trailing edge terminates against the body, hip, or knee are based on several specimens where the wing membrane is either incomplete or has undergone post-mortem contraction. An ankle attachment does not rule out a high aspect ratio wing as the curvature of the trailing edge and the ratio of the fore to hind limbs also play a major role in determining the final shape of the membrane.", "keyphrases": ["extent", "pterosaur", "vertebrate", "impression", "wing membrane"]}
{"id": "10.1111/brv.12238", "title": "Fossils of parasites: what can the fossil record tell us about the evolution of parasitism?", "abstract": "Parasites are common in many ecosystems, yet because of their nature, they do not fossilise readily and are very rare in the geological record. This makes it challenging to study the evolutionary transition that led to the evolution of parasitism in different taxa. Most studies on the evolution of parasites are based on phylogenies of extant species that were constructed based on morphological and molecular data, but they give us an incomplete picture and offer little information on many important details of parasite\u2013host interactions. The lack of fossil parasites also means we know very little about the roles that parasites played in ecosystems of the past even though it is known that parasites have significant influences on many ecosystems. The goal of this review is to bring attention to known fossils of parasites and parasitism, and provide a conceptual framework for how research on fossil parasites can develop in the future. Despite their rarity, there are some fossil parasites which have been described from different geological eras. These fossils include the free\u2010living stage of parasites, parasites which became fossilised with their hosts, parasite eggs and propagules in coprolites, and traces of pathology inflicted by parasites on the host's body. Judging from the fossil record, while there were some parasite\u2013host relationships which no longer exist in the present day, many parasite taxa which are known from the fossil record seem to have remained relatively unchanged in their general morphology and their patterns of host association over tens or even hundreds of millions of years. It also appears that major evolutionary and ecological transitions throughout the history of life on Earth coincided with the appearance of certain parasite taxa, as the appearance of new host groups also provided new niches for potential parasites. As such, fossil parasites can provide additional data regarding the ecology of their extinct hosts, since many parasites have specific life cycles and transmission modes which reflect certain aspects of the host's ecology. The study of fossil parasites can be conducted using existing techniques in palaeontology and palaeoecology, and microscopic examination of potential material such as coprolites may uncover more fossil evidence of parasitism. However, I also urge caution when interpreting fossils as examples of parasites or parasitism\u2010induced traces. I point out a number of cases where parasitism has been spuriously attributed to some fossil specimens which, upon re\u2010examination, display traits which are just as (if not more) likely to be found in free\u2010living taxa. The study of parasite fossils can provide a more complete picture of the ecosystems and evolution of life throughout Earth's history.", "keyphrases": ["parasite", "parasite\u2013host interaction", "host", "coprolite"]}
{"id": "paleo.011183", "title": "Phanerozoic survivors: Actinopterygian evolution through the Permo\u2010Triassic and Triassic\u2010Jurassic mass extinction events", "abstract": "Actinopterygians (ray\u2010finned fishes) successfully passed through four of the big five mass extinction events of the Phanerozoic, but the effects of these crises on the group are poorly understood. Many researchers have assumed that the Permo\u2010Triassic mass extinction (PTME) and end\u2010Triassic extinction (ETE) had little impact on actinopterygians, despite devastating many other groups. Here, two morphometric techniques, geometric (body shape) and functional (jaw morphology), are used to assess the effects of these two extinction events on the group. The PTME elicits no significant shifts in functional disparity while body shape disparity increases. An expansion of body shape and functional disparity coincides with the neopterygian radiation and evolution of novel feeding adaptations in the Middle\u2010Late Triassic. Through the ETE, small decreases are seen in shape and functional disparity, but are unlikely to represent major changes brought about by the extinction event. In the Early Jurassic, further expansions into novel areas of ecospace indicative of durophagy occur, potentially linked to losses in the ETE. As no evidence is found for major perturbations in actinopterygian evolution through either extinction event, the group appears to have been immune to two major environmental crises that were disastrous to most other organisms.", "keyphrases": ["actinopterygian evolution", "mass extinction event", "phanerozoic"]}
{"id": "10.7717/peerj.3433", "title": "The fossil Osmundales (Royal Ferns)\u2014a phylogenetic network analysis, revised taxonomy, and evolutionary classification of anatomically preserved trunks and rhizomes", "abstract": "The Osmundales (Royal Fern order) originated in the late Paleozoic and is the most ancient surviving lineage of leptosporangiate ferns. In contrast to its low diversity today (less than 20 species in six genera), it has the richest fossil record of any extant group of ferns. The structurally preserved trunks and rhizomes alone are referable to more than 100 fossil species that are classified in up to 20 genera, four subfamilies, and two families. This diverse fossil record constitutes an exceptional source of information on the evolutionary history of the group from the Permian to the present. However, inconsistent terminology, varying formats of description, and the general lack of a uniform taxonomic concept renders this wealth of information poorly accessible. To this end, we provide a comprehensive review of the diversity of structural features of osmundalean axes under a standardized, descriptive terminology. A novel morphological character matrix with 45 anatomical characters scored for 15 extant species and for 114 fossil operational units (species or specimens) is analysed using networks in order to establish systematic relationships among fossil and extant Osmundales rooted in axis anatomy. The results lead us to propose an evolutionary classification for fossil Osmundales and a revised, standardized taxonomy for all taxa down to the rank of (sub)genus. We introduce several nomenclatural novelties: (1) a new subfamily Itopsidemoideae (Guaireaceae) is established to contain Itopsidema, Donwelliacaulis, and Tiania; (2) the thamnopteroid genera Zalesskya, Iegosigopteris, and Petcheropteris are all considered synonymous with Thamnopteris; (3) 12 species of Millerocaulis and Ashicaulis are assigned to modern genera (tribe Osmundeae); (4) the hitherto enigmatic Aurealcaulis is identified as an extinct subgenus of Plenasium; and (5) the poorly known Osmundites tuhajkulensis is assigned to Millerocaulis. In addition, we consider Millerocaulis stipabonettiorum a possible member of Palaeosmunda and Millerocaulis estipularis as probably constituting the earliest representative of the (Todea-)Leptopteris lineage (subtribe Todeinae) of modern Osmundoideae.", "keyphrases": ["fossil osmundales", "evolutionary classification", "trunk"]}
{"id": "10.1017/pab.2019.24", "title": "Early Paleocene tropical forest from the Ojo Alamo Sandstone, San Juan Basin, New Mexico, USA", "abstract": "Abstract. Earliest Paleocene megafloras from North America are hypothesized to be low diversity and dominated by long-lived cosmopolitan species following the Cretaceous/Paleogene (K/Pg) mass extinction. However, megafloras used to develop this hypothesis are from the Northern Great Plains (NGP) of North America, and relatively little is known about floras from southern basins. Here, we present a quantitative analysis of an earliest Paleocene megaflora (<350 kyr after K/Pg boundary) from the Ojo Alamo Sandstone in the San Juan Basin (SJB), New Mexico. The megaflora, comprising 53 morphotypes, was dominated by angiosperms, with accessory taxa composed of pteridophytes, lycophytes, and conifers. Diversity analyses indicate a species-rich, highly uneven, and laterally heterogeneous flora. Paleoclimate estimates using multivariate and univariate methods indicate warm temperatures and relatively high precipitation consistent with a modern tropical seasonal forest. When compared with contemporaneous floras from the Denver Basin (DB) of Colorado and the Williston Basin (WB) of North Dakota, the SJB flora had significantly higher species richness but lower evenness. Paleoclimate estimates from the SJB were 7\u201314\u00b0C warmer than the estimates for the DB and WB, indicating a shift from a temperate forest in the NGP to a tropical forest in the SJB. These results demonstrate the presence of a latitudinal floral diversity and paleoclimatic gradient during the earliest Paleocene in western North America. We hypothesize that the warm, wet conditions in the earliest Paleocene SJB drove rapid rates of speciation following the K/Pg boundary, resulting in a diverse and heterogeneous flora.", "keyphrases": ["tropical forest", "ojo alamo sandstone", "san juan basin"]}
{"id": "10.1029/1999PA900033", "title": "Variation of atmospheric CO2 by ventilation of the ocean's deepest water", "abstract": "A new box model for glacial-interglacial changes in atmospheric CO2 produces lower levels of atmospheric CO 2 without changes in biological production or nutrient chemistry. The model treats the boundary between middepth water and deep water as a chemical divide that separates low-CO 2 water above from high-CO 2 water below. Atmospheric CO 2 is reduced 21 ppm by reduced ventilation of the deep water below the divide. A further reduction of 36 ppm is due to CaCO 3 compensation in response to lower CO3 = below the divide. Colder surface temperatures account for an additional 23 ppm of CO 2 reduction. The new mechanism leaves the glacial atmosphere lighter in \u00f513C than in preindustrial time, as seen in ice cores and fossil plant material. Bottom water below the divide becomes strongly depleted in \u00f513C without a change in nutrient concentrations.", "keyphrases": ["atmospheric co2", "ventilation", "deep water"]}
{"id": "10.24199/j.mmv.2002.59.7", "title": "A revision of the Australian genus Umbilia (Gastropoda: Cypraeidae)", "abstract": "Darragh, T.A., 2002. A revision of the Australian genus Umbilia (Gastropoda: Cypraeidae). Memoirs of Museum Victoria 59(2): 355\u2013392. Umbilia, an endemic Australian genus of cool-water cowry, comprises 11 species ranging in age from Late Oligocene to Recent, of which four species are known only in the living fauna. Fossil species occur in the Eucla, St Vincent, Murray, Otway, Bass and Gippsland Basins, and living species range from Western Australia to central Queensland. Species of the genus probably have no free-swimming larval stage, so that there is considerable morphological variability which has led to the creation of many synonyms. Two subgenera are recognised here, Umbilia (Umbilia), with ten species, U. prosila sp. nov., U. leptorhyncha, U. petilirostris sp. nov., U. platyrhyncha, U. angustior, U. eximia (= brevis, maccoyi, frankstonensis, montismarthae and sphaerodoma), U. hesitata (= beddomei, cera, howelli and tatei?), U. siphonata (= breviplicata), U. armeniaca and U. capricornica, and U. (Palliocypraea) with one species, U.(P.) gastroplax. A possible ancestor of Umbilia, Palaeocypraea? eripnides, from the Upper Paleocene\u2013Lower Eocene, of the Chatham Is, New Zealand, is newly described. Rhynchocypraea Cossmann, 1898 (type species Cypraea leptorhyncha McCoy) is synonymised with Umbilia.", "keyphrases": ["revision", "australian genus umbilia", "cypraeidae"]}
{"id": "paleo.005282", "title": "Seawater chemistry and biomineralization: did trepostome bryozoans become hypercalcified in the \u2018calcite sea\u2019 of the Ordovician?", "abstract": "Secular variations in the proportion of Mg and Ca ions in seawater during the Phanerozoic have driven alternations between calcite seas (Mg:Ca<2) and aragonite seas (Mg:Ca>2). There is mounting evidence that these changes in seawater chemistry have impacted the evolution of marine organisms constructing calcareous skeletons, favouring calcite as the CaCO 3 biomineral during times of calcite seas but aragonite during times of aragonite seas. It has been suggested that some organisms became hypercalcified when the mineralogy of their skeletons matched seawater type. This paper tests the proposal that calcitic trepostome bryozoans ('stony bryozoans') became hypercalcified in the calcite sea of the Ordovician. Data on two independent hypercalcification proxies-the diameter of branches, and exozonal wall thickness-have been compiled from the literature for ramose trepostome species from the Ordovician (calcite sea), Devonian (calcite sea) and Permian (aragonite sea). No significant difference was found in branch diameter between the calcite and aragonite sea periods, whereas wall thickness was found to be greater in the Permian than in the Ordovician and Devonian, counter to expectations. Either these two parameters are inadequate as proxies for hypercalcification or, more likely, trepostomes did not become hypercalcified in the calcite sea of the Early Palaeozoic, probably because they exerted a higher degree of control over their biomineralization than some other groups such as corals.", "keyphrases": ["biomineralization", "bryozoan", "calcite sea"]}
{"id": "10.1080/03115518.2016.1180027", "title": "First report of Cixiidae insect fossils from the Miocene of the northeastern Tibetan Plateau and their palaeoenvironmental implications", "abstract": "Li, Y., Liu, X., Ren, D., Li, X. & Yao, Y., June 2016. First report of Cixiidae insect fossils from the Miocene of the northeastern Tibetan Plateau and their palaeoenvironmental implications. Alcheringa 41, xxx\u2013xxx. ISSN 0311-5518. A new insect species, Cixius discretus (Hemiptera, Fulgoromorpha), from the Lower Miocene Garang Formation of Zeku County, Qinghai Province (northeastern Tibetan Plateau) is described. This species can be assigned to Cixiidae and represents the first fossil representative of this family from Qinghai Province. Based on the recent single-origin hypothesis and the distribution of tectonic plates in the Cretaceous, we consider that ancient Cixius had dispersed globally prior to the Cretaceous. Through analysis of the habitats of extant Cixius, the palaeoclimate and fossil flora of the Zeku area during the Miocene, we interpret the climate of Zeku in the early Miocene to have been warm-temperate and mildly arid. The new species constitutes evidence of wooded and shrubby habitats in Zeku during the Miocene. Yi Li [liy0124@sina.com], XiaoHui Liu [liuxh8917@163.com], Dong Ren [rendong@mail.cnu.edu.cn] and YunZhi Yao [yunzhi@cnu.edu.cn], College of Life Sciences, Capital Normal University, Xisanhuanbeilu 105, Haidian District, Beijing 100048, PR China; XiangChuan Li [lzulixiangchuan@163.com], College of Earth Sciences and Resources & Key Laboratory of Western Mineral Resources and Geological Engineering of the Ministry of Education, Chang\u2019an University, Xi\u2019an 710054, PR China.", "keyphrases": ["cixiidae insect fossil", "miocene", "palaeoenvironmental implication"]}
{"id": "paleo.005307", "title": "Ignoring stratigraphic age uncertainty leads to erroneous estimates of species divergence times under the fossilized birth\u2013death process", "abstract": "Fossil information is essential for estimating species divergence times, and can be integrated into Bayesian phylogenetic inference using the fossilized birth\u2013death (FBD) process. An important aspect of palaeontological data is the uncertainty surrounding specimen ages, which can be handled in different ways during inference. The most common approach is to fix fossil ages to a point estimate within the known age interval. Alternatively, age uncertainty can be incorporated by using priors, and fossil ages are then directly sampled as part of the inference. This study presents a comparison of alternative approaches for handling fossil age uncertainty in analysis using the FBD process. Based on simulations, we find that fixing fossil ages to the midpoint or a random point drawn from within the stratigraphic age range leads to biases in divergence time estimates, while sampling fossil ages leads to estimates that are similar to inferences that employ the correct ages of fossils. Second, we show a comparison using an empirical dataset of extant and fossil cetaceans, which confirms that different methods of handling fossil age uncertainty lead to large differences in estimated node ages. Stratigraphic age uncertainty should thus not be ignored in divergence time estimation and instead should be incorporated explicitly.", "keyphrases": ["stratigraphic age uncertainty", "specie divergence time", "prior"]}
{"id": "10.1127/0077-7749/2014/0398", "title": "Middle Jurassic Monte Fallano Plattenkalk (Campania, southern Italy): first report on terrestrial plants, decapod crustaceans and fishes", "abstract": "A new Jurassic fossiliferous Plattenkalk has been discovered at Monte Fallano (Caserta, Campania, southern Italy). Biostratigraphic analyses indicate a Bajocian/Bathonian age (Middle Jurassic). The fossil assemblage consists of terrestrial plants, invertebrates (bivalves, gastropods, decapod crustaceans, isopods and insect larvae) and vertebrates (fishes). This study takes terrestrial plants, fishes, and decapod crustaceans into account, giving systematic, taphonomic and palaeoenvironmental considerations. The land flora consists of impressions of sterile and fertile shoots of microphyllous conifers; leaves with parallel venation of unknown taxonomy are also present. The genera Cupressinocladus, Brachyphyllum and Araucarites are documented and their microscopical characters are examined. Plant remains possibly represent a stable biotope, as floral composition presents no variation along the section studied. Taphonomic considerations on plant fossils suggest parautochtonous deposition. The study of the rich decapod crustacean fauna includes Acanthochirana liburiaensis n. sp. (Aegeridae Burkenroad, 1963), Casertanus sabellicus n. gen., n. sp. (Sergestidae dana, 1852), Eryma osciensis (Erymidae Van Straelen, 1925) and Tethyseryon campanicus n. gen., n. sp. (Eryonidae de Haan, 1841). Casertanus sabellicus n. gen., n. sp. is the oldest representative of Sergestidae in the fossil record, extending the stratigraphic range of this family into the Middle Jurassic. Tethyseryon campanicus n. gen., n. sp. is the earliest species in which juveniles have been identified within the Eryonidae; the presence of both juveniles and adults in the depositional environment of Monte Fallano suggests that this species was autochthonous or parautochthonous. Preliminary data on fossil fishes sample have lead to the identification of leptolepid, macrosemiid among which Notagogus (Neonotagogus) denticulatus, pleuropholid (Pleuropholis) and pycnodontid fishes; other primitive teleosts and incomplete and indeterminate \u201cganoid\u201d fishes are also reported. Based on the sedimentological data and the characteristics of decapod crustaceans and fishes, the investigated record of the Monte Fallano section represents the product of depositional process in shallow water carbonate platform settings.", "keyphrases": ["campania", "terrestrial plant", "decapod crustacean"]}
{"id": "paleo.001756", "title": "Formation binning: a new method for increased temporal resolution in regional studies, applied to the Late Cretaceous dinosaur fossil record of North America", "abstract": "The advent of palaeontological occurrence databases has allowed for detailed reconstruction and analyses of species richness through deep time. While a substantial literature has evolved ensuring that taxa are fairly counted within and between different time periods, how time itself is divided has received less attention. Stage\u2010level or equal\u2010interval age bins have frequently been used for regional and global studies in vertebrate palaeontology. However, when assessing diversity at a regional scale, these resolutions can prove inappropriate with the available data. Herein, we propose a new method of binning geological time for regional studies that intrinsically incorporates the chronostratigraphic heterogeneity of different rock formations to generate unique stratigraphic bins. We use this method to investigate the diversity dynamics of dinosaurs from the Late Cretaceous of the Western Interior of North America prior to the Cretaceous\u2013Palaeogene mass extinction. Increased resolution through formation binning pinpoints the Maastrichtian diversity decline to between 68 and 66 Ma, coinciding with the retreat of the Western Interior Seaway. Diversity curves are shown to exhibit volatile patterns using different binning methods, supporting claims that heterogeneous biases in this time\u2010frame affect the pre\u2010extinction palaeobiological record. We also show that the apparent high endemicity of dinosaurs in the Campanian is a result of non\u2010contemporaneous geological units within large time bins. This study helps to illustrate the utility of high\u2010resolution, regional studies to supplement our understanding of factors governing global diversity in deep time and ultimately how geology is inherently tied to our understanding of past changes in species richness.", "keyphrases": ["new method", "resolution", "late cretaceous", "north america", "western interior seaway"]}
{"id": "10.1139/z85-139", "title": "Ephemeroid wing venation based upon new gigantic Carboniferous mayflies and basic morphology, phylogeny, and metamorphosis of pterygote insects (Insecta, Ephemerida)", "abstract": "Gigantic as well as very large mayflies from the middle Upper Carboniferous (Westphalian) strata of Europe and North America are described: the adult and nymph of Bojophlebia prokopi n. gen., n. sp. (Bojophlebiidae n. fam.) and the nymphs of Lithoneura piecko n. sp. and Lithoneura clayesi n. sp. (Syntonopteridae). Evolution of ephemerid wing venation during 300 million years is summarized. Autapomorphic, apomorphic, and plesiomorphic character states of venation are categorized. Venational nomenclature of Recent Ephemerida is emended based on its evolutionary changes. Evidence that wing veins occurred primitively as a pair of fluted sectors is documented in Carboniferous mayflies in the costa, subcosta, radius, anal, and jugal. Ephemeroids and odonatoids are sister groups that share the veinal anal brace AA fused with CuP at an area important for flight. Ancestral Odonatoephemerida are the sister group of the extinct haustellate Paleoptera. The Carboniferous nymphs bear three pairs of almost homonomous th...", "keyphrases": ["wing venation", "carboniferous mayfly", "mayfly"]}
{"id": "paleo.004556", "title": "Ontogenetic trajectories of septal spacing in Early Jurassic belemnites from Germany and France, and their palaeobiological implications", "abstract": "Based on well\u2010preserved belemnites, the ontogenetic trajectories of septal spacing between succeeding chambers were analysed. In the examined species (Passaloteuthis laevigata, Parapassaloteuthis zieteni and Pseudohasitites longiformis) that come from Buttenheim, Germany, and Lixhausen, France, the ontogenetic trajectories of septal spacing follow exponentially increasing trends with no decreasing phase of septal crowding during the earliest ontogenetic stage. The absence of a decreasing trend at the earliest ontogenetic stage is a unique character in contrast with those in modern cuttlefish and ancient and modern nautiloids, in which the decreasing trends are related to hatching events. These ontogenetic septal spacing trends suggest that the belemnite hatchlings had only a protoconch with no chamber. These belemnite hatchlings with no chamber and therefore small embryonic shell diameter are similar to those of ammonoids. Significant difference in a statistical test that compared the protoconch size between the two localities, might suggest that there was limited transportation at the embryonic stage, although it could also just indicate differences in regional environmental conditions, age and/or degree of time averaging which might differ between the examined taxa.", "keyphrases": ["septal spacing", "germany", "ontogenetic trajectory"]}
{"id": "10.1080/02724634.1997.10011000", "title": "Modified perichondral ossification and the evolution of paddle-like limbs in ichthyosaurs and plesiosaurs", "abstract": "ABSTRACT Evolution of paddle-like limbs in ichthyosaurs and plesiosaurs is correlated with loss of perichondral bone from the shafts of long bones. Among ichthyosaurs, loss of perichondral bone is first observed on the shafts of digit bones of Early Triassic taxa. Late Triassic ichthyosaurs show perichondral bone loss on the postaxial margins of the ulna and fibula. Among plesiosaurs, loss of perichondral bone is first observed on the postaxial margins of the ulna and fibula of Lower Jurassic taxa. In geologically later species of both groups, perichondral bone is progressively lost on all margins of the ulna and radius, and fibula and tibia. Late Triassic and Jurassic ichthyosaurs show an absence of perichondral ossifications on all limb bones distal to the humerus and femur. Delayed ossification of the mesopodium is not observed in ichthyosaurs. Evolutionary changes to the ossification of perichondral tissues appear to affect the sequence of limb ossification as long bones lose perichondral bone. Limb b...", "keyphrases": ["perichondral ossification", "paddle-like limb", "ichthyosaur"]}
{"id": "paleo.012570", "title": "Calibrating the zenith of dinosaur diversity in the Campanian of the Western Interior Basin by CA-ID-TIMS U\u2013Pb geochronology", "abstract": "The spectacular fossil fauna and flora preserved in the Upper Cretaceous terrestrial strata of North America\u2019s Western Interior Basin record an exceptional peak in the diversification of fossil vertebrates in the Campanian, which has been termed the \u2018zenith of dinosaur diversity\u2019. The wide latitudinal distribution of rocks and fossils that represent this episode, spanning from northern Mexico to the northern slopes of Alaska, provides a unique opportunity to gain insights into dinosaur paleoecology and to address outstanding questions regarding faunal provinciality in connection to paleogeography and climate. Whereas reliable basin-wide correlations are fundamental to investigations of this sort, three decades of radioisotope geochronology of various vintages and limited compatibility has complicated correlation of distant fossil-bearing successions and given rise to contradictory paleobiogeographic and evolutionary hypotheses. Here we present new U\u2013Pb geochronology by the CA-ID-TIMS method for 16 stratigraphically well constrained bentonite beds, ranging in age from 82.419 \u00b1 0.074 Ma to 73.496 \u00b1 0.039 Ma (2\u03c3 internal uncertainties), and the resulting Bayesian age models for six key fossil-bearing formations over a 1600 km latitudinal distance from northwest New Mexico, USA to southern Alberta, Canada. Our high-resolution chronostratigraphic framework for the upper Campanian of the Western Interior Basin reveals that despite their contrasting depositional settings and basin evolution histories, significant age overlap exists between the main fossil-bearing intervals of the Kaiparowits Formation (southern Utah), Judith River Formation (central Montana), Two Medicine Formation (western Montana) and Dinosaur Park Formation (southern Alberta). Pending more extensive paleontologic collecting that would allow more rigorous faunal analyses, our results support a first-order connection between paleoecologic and fossil diversities and help overcome the chronostratigraphic ambiguities that have impeded the testing of proposed models of latitudinal provinciality of dinosaur taxa during the Campanian.", "keyphrases": ["dinosaur diversity", "campanian", "western interior basin"]}
{"id": "10.1080/17445647.2015.1115785", "title": "Fossil marine vertebrates of Cerro Los Quesos: Distribution of cetaceans, seals, crocodiles, seabirds, sharks, and bony fish in a late Miocene locality of the Pisco Basin, Peru", "abstract": "ABSTRACT One-hundred and ninety-two fossil marine vertebrate specimens, preserved as bone elements cropping out at Cerro Los Quesos (Pisco Basin, Peru), are identified and reported on a 1:4,000 scale geological map and in the corresponding stratigraphic section. All the fossils originate from the Pisco Formation, which is dated in this area to the late Miocene (from 7.55\u2005Ma to \u22656.71\u2005Ma, based on 40Ar/39Ar analyses of three volcanic ash layers along the section). Specimens are particularly concentrated near the top of the two main hills, where the geologically youngest portion of the examined section crops out. The impressive fossil assemblage includes cetaceans (91.6%), represented by mysticetes (balaenopteroids and cetotheriids) and odontocetes (phocoenids, physeteroids, and ziphiids, including the holotype of Nazcacetus urbinai). Seals, a crocodile, a seabird, bony fish, and sharks are also reported. Isolated large teeth of Carcharocles and Cosmopolitodus are common and, in several instances, associated to mysticete skeletons. Together with a similar work recently published for the other late Miocene locality of Cerro Colorado, this work represents a case study for the detailed inventory of the extraordinary paleontological heritage of the Pisco Basin. As such, it constitutes the basis for future taphonomic, paleoecological, and systematic studies, as well as for a much-needed conservation effort.", "keyphrases": ["cetacean", "shark", "late miocene locality"]}
{"id": "10.1098/rspb.2016.0360", "title": "Madagascar's ephemeral palaeo-grazer guild: who ate the ancient C4 grasses?", "abstract": "Madagascar today is 65% grassland. Its grassy biomes were widely interpreted as \u2018anthropogenic\u2019 before Bond et al. [[1][1]] challenged that view, claiming that grasses colonized Madagascar during the Miocene. Through an analysis of grass clade endemism and specialization, Vorontsova et al. [[2][", "keyphrases": ["guild", "grass", "madagascar", "grazer"]}
{"id": "paleo.011910", "title": "Squamation and ecology of thelodonts", "abstract": "Thelodonts are an enigmatic group of Paleozoic jawless vertebrates that have been well studied from taxonomical, biostratigraphic and paleogeographic points of view, although our knowledge of their ecology and mode of life is still scant. Their bodies were covered by micrometric scales whose morphology, histology and the developmental process are extremely similar to those of extant sharks. Based on these similarities and on the well-recognized relationship between squamation and ecology in sharks, here we explore the ecological diversity and lifestyles of thelodonts. For this we use classic morphometrics and discriminant analysis to characterize the squamation patterns of a significant number of extant shark species whose ecology is well known. Multivariate analyses have defined a characteristic squamation pattern for each ecological group, thus establishing a comparative framework for inferring lifestyles in thelodonts. We then use this information to study the squamation of the currently described 147 species of thelodonts, known from both articulated and disarticulated remains. Discriminant analysis has allowed recognizing squamation patterns comparable to those of sharks and links them to specific ecological groups. Our results suggest a remarkable ecological diversity in thelodonts. A large number of them were probably demersal species inhabiting hard substrates, within caves and crevices in rocky environments or reefs, taking advantage of the flexibility provided by their micromeric squamations. Contrary to classical interpretations, only few thelodonts were placed among demersal species inhabiting sandy and muddy substrates. Schooling species with defensive scales against ectoparasites could be also abundant suggesting that social interactions and pressure of ectoparasites were present in vertebrates as early the Silurian. The presence of species showing scales suggestive of low to moderate speed and a lifestyle presumably associated with open water environments indicates adaptation of thelodonts to deep water habitats. Scale morphology suggests that some other thelodonts were strong-swimming pelagic species, most of them radiating during the Early Devonian in association with the Nekton Revolution.", "keyphrases": ["ecology", "thelodont", "squamation"]}
{"id": "10.1111/iar.12113", "title": "Paleoenvironments of the evolving Pliocene to early Pleistocene foreland basin in northwestern Taiwan: An example from the Dahan River section", "abstract": "The overriding of the Luzon volcanic arc atop the underlying Chinese rifted\u2010continental margin has caused the formation of the Taiwan mountain belts and a peripheral foreland basin west of the orogen since the late Miocene. In this study, lithofacies analysis and calcareous nannofossil biostratigraphic investigations of the Dahan River section in northwestern (NW) Taiwan were performed. Our results offer insights into the temporal evolution of the sedimentary environments and the competing effects of the sedimentation and basin tectonics of the NW Taiwan foreland basin from the Pliocene to early Pleistocene. Nannofossil biostratigraphic studies showed that the upper Kueichulin Formation and the overlying Chinshui Shale can be assigned to the NN15 biozone of the Pliocene age, and the Cholan Formation pertains to NN16\u2013NN18 of the early Pleistocene. The NN15\u2013NN16 boundary coincides roughly with the boundary of the Chinshui Shale and Cholan Formation. We recognized three major sedimentary environments in the studied foreland succession comprising the upper Kueichulin Formation, Chinshui Shale, Cholan Formation and Yangmei Formation, in ascending order. During the deposition of the upper Kueichulin Formation in the early Pliocene, the dominant environment was a wave\u2010 and tide\u2010influenced open marine setting. During the late Pliocene, the environment deepened to an outer\u2010offshore setting when the sediments of Chinshui Shale were accumulated. In the Pleistocene, the environment then shallowed to wave\u2010dominated estuaries during the deposition of the lower Cholan Formation, and the basin was rapidly filled, generating a meandering and sandy braided river environment during the deposition of the upper Cholan to the Yangmei Formation. In summary, the evolution of sedimentary environments in the studied succession shows a deepening then a shallowing and coarsening upward trend during the period from the Pliocene to the Pleistocene, spanning the age from approximately 4 to 1 Ma.", "keyphrases": ["pleistocene", "foreland basin", "dahan river section"]}
{"id": "10.3853/j.0067-1975.49.1997.249", "title": "Morphological and ecological disparity in Naraoiids (Arthropoda) from the Early Cambrian Chengjiang fauna, China", "abstract": "Misszhouia longicaudata (Zhang & Hou) from the Chengjiang lagerstatte is separated from Naraoia Walcott by its antennular orientation, its smaller cephalic caeca and gut, lanceolate distal exopod lobe, and partial fusion of the exopod and first endopodal podomere. Naraoia spinosa Zhang & Hou (also from Chengjiang) shares derived characters with the type species, N. compacta. Deposit feeding is suggested for Naraoia spinosa by both morphology and preservational circumstances. New material shows previously unknown features in Misszhouia longicaudata, including frontal organs anterior to a sclerotised lobe of the hypo stomal complex, the position of the mouth opening, details of antennule and biramous limb attachments, morphology of the sternites and limb rami, and the structure of the ventral cuticle in the cephalon and pleural areas. CHEN, JUN-YUAN, GREGORY D. EDGECOMBE & LARS RAMSKOLD, 1997. Morphological and ecological disparity in naraoiids (Arthropoda) from the Early Cambrian Chengjiang fauna, China. Records of the Australian Museum 49(1): 1-24. The systematic status of Naraoia Walcott, 1912, and several allied non-mineralised arthropods has most recently been reviewed by Fortey & Theron (1994). These workers provided evidence that Naraoiidae Walcott, 1912, could be defined as a monophyletic group that unites the Lower-Middle Cambrian Naraoia, the Lower Cambrian Liwia Dzik & Lendzion, 1988, the Ordovician Tariccoia Hammann et al., 1990, and the Upper Ordovician Soomaspis Fortey & Theron, 1994. Among a range of Early Palaeozoic Arachnata that are known from exceptionally-preserved faunas, naraoiids are of particular significance because they have been regarded as a possible sister or stem-group to trilobites (Fortey & Theron, 1994; Shu et al., 1995).", "keyphrases": ["ecological disparity", "arthropoda", "cambrian chengjiang fauna"]}
{"id": "10.1080/14772019.2010.525536", "title": "Statistical approach for inferring ecology of Mesozoic birds", "abstract": "The ability to identify the ecological role an organism plays is fundamental to modern ecology and is an important goal of palaeontological studies. Morphometrics has the potential to be a statistically robust means of furthering this goal, identifying ecomorphological trends within a group of organisms. The dramatic morphological and ecological diversity of modern and fossil birds makes them ideal for ecomorphological studies, and the vast increase in known Mesozoic avian diversity opens numerous possibilities for applying modern ecomorphology to enhance our understanding of avian diversification in the Mesozoic. This study presents a large morphometric database of modern birds analysed using a multivariate statistical approach, in order to identify correlations between ecology and morphology. These relationships were also examined in a number of Mesozoic birds in order to investigate both the ecological diversification of early birds as a whole and the specific ecological roles individual taxa may have played.", "keyphrases": ["ecology", "mesozoic bird", "statistical approach"]}
{"id": "10.3354/meps12918", "title": "Gauging benthic recovery from 20th century pollution on the southern California continental shelf using bivalves from sediment cores", "abstract": "Urbanization of coasts creates stresses on adjacent marine communities, but the full impact is seldom known owing to scarce historical records. Paleoecological analysis of sediment cores can be a powerful means of reconstructing baseline benthic communities, but is particularly challenging for continental shelves where dead-shell assemblages are prone to greater time-averaging than in natural sediment sinks such as deltas, coastal bays, and estuaries. We compared temporal changes in the composition of bivalve shell assemblages collected from box cores on the Palos Verdes (southern California, USA) shelf to a 40 yr time series of annually collected living benthic assemblages in the same area in order to calibrate bivalve core assemblages to known changes in community composition during wastewater remediation. Older (pre-1970) core assemblages were then used to reveal the nature of bivalve communities from the early 20th century and the extent to which present-day communities match, i.e. have recovered to, early urban baselines. Deep bioturbation and only moderate sedimentation rates (0.2 cm yr\u22121) damp the magnitude and rapidity of changes in core assemblage composition. Despite the geological complexity, bivalve core assemblages (1) detect known late 20th century dynamics in broad outline, (2) reveal the undocumented rise of chemosymbiont-bearing bivalves during the early 20th century, and (3) establish that the present-day community is largely but not fully recovered to its pre-effluent, early urban (1900\u22121930) baseline. Thus, cores capture the nature, timing, and duration of macrobenthic response to 20th century wastewater, validating this approach for shelf settings with scarce or no historical data.", "keyphrases": ["southern california", "continental shelf", "sediment core"]}
{"id": "10.1111/brv.12168", "title": "Making sense of \u2018lower\u2019 and \u2018upper\u2019 stem\u2010group Euarthropoda, with comments on the strict use of the name Arthropoda von Siebold, 1848", "abstract": "The ever\u2010increasing number of studies that address the origin and evolution of Euarthropoda \u2013 whose extant representatives include chelicerates, myriapods, crustaceans and hexapods \u2013 are gradually reaching a consensus with regard to the overall phylogenetic relationships of some of the earliest representatives of this phylum. The stem\u2010lineage of Euarthropoda includes numerous forms that reflect the major morphological transition from a lobopodian\u2010type to a completely arthrodized body organization. Several methods of classification that aim to reflect such a complex evolutionary history have been proposed as a consequence of this taxonomic diversity. Unfortunately, this has also led to a saturation of nomenclatural schemes, often in conflict with each other, some of which are incompatible with cladistic\u2010based methodologies. Here, I review the convoluted terminology associated with the classification of stem\u2010group Euarthropoda, and propose a synapomorphy\u2010based distinction that allows \u2018lower stem\u2010Euarthropoda\u2019 (e.g. lobopodians, radiodontans) to be separated from \u2018upper stem\u2010Euarthropoda\u2019 (e.g. fuxianhuiids, Cambrian bivalved forms) in terms of the structural organization of the head region and other aspects of overall body architecture. The step\u2010wise acquisition of morphological features associated with the origins of the crown\u2010group indicate that the node defining upper stem\u2010Euarthropoda is phylogenetically stable, and supported by numerous synapomorphic characters; these include the presence of a deutocerebral first appendage pair, multisegmented head region with one or more pairs of post\u2010ocular differentiated limbs, complete body arthrodization, posterior\u2010facing mouth associated with the hypostome/labrum complex, and post\u2010oral biramous arthropodized appendages. The name \u2018Deuteropoda\u2019 nov. is proposed for the scion (monophyletic group including the crown\u2010group and an extension of the stem\u2010group) that comprises upper stem\u2010Euarthropoda and Euarthropoda. A brief account of common terminological inaccuracies in recent palaeontological studies evinces the utility of Deuteropoda nov. as a reference point for discussing aspects of early euarthropod phylogeny.", "keyphrases": ["stem\u2010group euarthropoda", "chelicerate", "deuteropoda", "euarthropod"]}
{"id": "10.1130/b30064.1", "title": "Tectonic history of the western Tethys since the Late Triassic", "abstract": "The tectonic history of the western Tethys since the Late Triassic is illustrated through a set of computer-generated plate reconstructions, which are based on a rigorous plate motions model of this region. The model is constrained by the Atlantic plate kinematics and on-land geologic evidence and defines 13 tectonic phases, spanning the time interval from the late Ladinian (230 Ma) to the present. The kinematics associated with the Late Triassic western Tethyan rifts produced the detachment of a large composite fragment from the northern margin of Gondwana. It can be considered as the eastern propagation of the central Pangea breakup. During the Early Jurassic these rift zones became inactive, while new zones of extension formed along the southern margin of Eurasia, the eastern margin of Iberia, and within the rifted northern Gondwana fragment itself. Plate motions associated with the first two extensional centers can still be considered as an eastern branch of the central Atlantic plate kinematics. Conversely, the kinematic parameters of the latter rift result from the composition of the Euler rotation describing the central Pangea breakup and the Euler pole of closure of the paleo\u2013Tethys ocean. The Late Triassic\u2013Early Jurassic rifting phases determined the formation of a number of independent microplates at the interface between Africa and Eurasia. Starting from the Early Cretaceous, convergence between Africa and Eurasia triggered further deformation within the dispersed continental fragments and the formation of backarc basins at the active margins, ultimately leading to an increase in the number of tectonic elements that were moving independently in the western Tethyan region during the Late Cretaceous and the Cenozoic. The proposed tectonic evolution of the western Tethys area is compatible with both global-scale plate kinematics and geological constraints from on-land data observed across the present-day mosaic of displaced terranes surrounding the Mediterranean region.", "keyphrases": ["western tethys", "late triassic", "tectonic history"]}
{"id": "10.1080/14772019.2019.1570569", "title": "Permian spiriferellid brachiopods from northern Pangaea: taxonomy, biostratigraphy, macroevolution and implications for palaeoenvironmental and palaeobiogeographical reconstructions", "abstract": "This study reports diverse spiriferellid brachiopods from the Permian rocks of Svalbard and adjacent areas (Arctic Canada and Subpolar Urals of Russia) located at the northern margin of Pangaea. In total, 11 brachiopod species in four genera are recognized and described in detail, including two new species (Spiriferella protodraschei and Arcullina? enokiani). According to our taxonomic investigation, morphological characteristics of the ventral sulcus and dorsal fold are relatively stable within each species, in spite of considerable intraspecific variations in shell outline and macro-ornamentation. In addition, both the arrangement of pustules, as a shell surface micro-ornamentation, and the development of delthyrial coverings are shown to be significant features for inferring phylogenetic relationships and for defining species. The best-known but still questionable taxon, Spiriferella keilhavii, is here identified as an endemic species restricted to Bj\u00f8rn\u00f8ya and, possibly, to central East Greenland; it is phylogenetically closest to S. loveni. Following the taxonomic revision, the stratigraphical ranges of the spiriferellids within the Kapp Starostin Formation in Spitsbergen are fully refined: three species, S. protodraschei, A. polaris and Timaniella wilczeki, are confined to the lowermost V\u00f8ringen Member (late Artinskian\u2013early Kungurian), whereas S. loveni dominates the overlying members with a much longer stratigraphical range (late Kungurian\u2013Lopingian?). This abrupt compositional change, along with comparable changes in other taxonomic groups, can be explained by a palaeoclimatic shift from cool to cold conditions between the V\u00f8ringen Member and the overlying Svenskeegga member. A similar biotic transition is identified between the Hambergfjellet and Miseryfjellet formations in Bj\u00f8rn\u00f8ya. On the other hand, S. loveni is abundant in the Late Permian strata of central East Greenland, but there it appears to be more costate in plication compared to its counterpart from Spitsbergen. It is suggested that this alteration in shell ornamentation may represent a possible response (adaptation) to warming arising from the southward migration of the species. http://zoobank.org/urn:lsid:zoobank.org:pub:85B863D2-DB42-4835-940A-2DE852C82178", "keyphrases": ["spiriferellid brachiopod", "pangaea", "northern margin", "kapp starostin formation"]}
{"id": "10.1098/rspb.2016.0256", "title": "Therian mammals experience an ecomorphological radiation during the Late Cretaceous and selective extinction at the K\u2013Pg boundary", "abstract": "It is often postulated that mammalian diversity was suppressed during the Mesozoic Era and increased rapidly after the Cretaceous\u2013Palaeogene (K\u2013Pg) extinction event. We test this hypothesis by examining macroevolutionary patterns in early therian mammals, the group that gave rise to modern placentals and marsupials. We assess morphological disparity and dietary trends using morphometric analyses of lower molars, and we evaluate generic level taxonomic diversity patterns using techniques that account for sampling biases. In contrast with the suppression hypothesis, our results suggest that an ecomorphological diversification of therians began 10\u201320 Myr prior to the K\u2013Pg extinction event, led by disparate metatherians and Eurasian faunas. This diversification is concurrent with ecomorphological radiations of multituberculate mammals and flowering plants, suggesting that mammals as a whole benefitted from the ecological rise of angiosperms. In further contrast with the suppression hypothesis, therian disparity decreased immediately after the K\u2013Pg boundary, probably due to selective extinction against ecological specialists and metatherians. However, taxonomic diversity trends appear to have been decoupled from disparity patterns, remaining low in the Cretaceous and substantially increasing immediately after the K\u2013Pg extinction event. The conflicting diversity and disparity patterns suggest that earliest Palaeocene extinction survivors, especially eutherian dietary generalists, underwent rapid taxonomic diversification without considerable morphological diversification.", "keyphrases": ["ecomorphological radiation", "selective extinction", "therian mammal"]}
{"id": "paleo.007392", "title": "The diet of Metaschizotherium bavaricum (Chalicotheriidae, Mammalia) from the MN 5 of Sandelzhausen (Germany) implied by the mesowear method", "abstract": "The genus Metaschizotherium is a Miocene member of the Schizotheriinae (Chalicotheriidae, Perissodactyla) and appears in the MN 5 of Southern Germany with the species M. bavaricum. The Chalicotheriidae have mostly been reconstructed as browsers. In this study, the mesowear method is applied to 11 upper premolars and molars of M. bavaricum from the Upper Freshwater Molasse locality of Sandelzhausen (MN 5). With this method the amount of abrasive and attritive dental wear is investigated and thus it provides a time-averaged signature of food abrasiveness of ungulates. Principal components analysis is performed on mesowear variables of M. bavaricum. This species is found to classify closest to extant mixed feeding ruminants. This indicates that the diet of M. bavaricum essentially included nonabrasive browse but also a certain amount of abrasive plant material. The composition of the diet of extant reference species indicates that this abrasiveness was most likely imposed by bark and whole branches. In the palaeoecological context of Sandelzhausen M. bavaricum occupied the dietary niche of a mixed feeder or an abrasion-dominated browser. A high degree of similarity is recognised between the mesowear patterns of M. bavaricum from Sandelzhausen and M. fraasi from the MN 6 of the Franconian Alb. This is interpreted as reflecting a similar dietary niche of the two species.", "keyphrases": ["chalicotheriidae", "sandelzhausen", "mesowear method", "ecological niche", "chalicothere"]}
{"id": "10.1029/2007GC001748", "title": "Paleogene deepwater mass composition of the tropical Pacific and implications for thermohaline circulation in a greenhouse world", "abstract": "The Pacific Ocean likely exerted the greatest marine influence on climate during the greenhouse interval of the Paleogene. The first step toward assessing the role of Pacific deepwater circulation in global heat transport is a comprehensive reconstruction of deepwater mass composition and circulation patterns. We present new deepwater mass Nd isotope data from ODP Leg 199 Sites 1215, 1217, 1219, and 1221 to augment the existing coverage provided by ferromanganese crust and fossil fish debris data. The new data corroborate the notion that the Pacific Ocean operated in a bimodal pattern with deepwater sources in both the Southern Ocean and North Pacific for much of the early to middle Paleogene. In addition, the data indicate that there was little to no influence of Atlantic waters on the deepwater composition of the tropical Pacific. The available deepwater Nd isotope data provide refined constraints on the geographic and depth range of influence of both a Southern Ocean and North Pacific deepwater mass. From \u223c65 to \u223c45 Ma, the deep tropical Pacific was the mixing location of deep waters sourced from the Southern Ocean and the North Pacific. The Southern Ocean deepwater mass extended from \u223c1800 m to abyssal depths. Until 53.6 Ma it circulated northward in the western Pacific at least as far as the paleolocation of Fe\u2010Mn Crust CLD01 (\u223c5\u00b0N paleolatitude) and in the eastern portion of the Pacific as far as Site 1215 (\u223c10\u00b0N paleolatitude). A North Pacific deepwater mass extended from at least \u223c2400 m to 2900 m water depth from \u223c65 to 54 Ma, south to Shatsky Rise (paleolatitude \u223c10\u201315\u00b0N), and possibly as far as Site 1215, 700 km to the south of Shatsky Rise Sites 1209 and 1211.", "keyphrases": ["deepwater mass composition", "tropical pacific", "paleogene"]}
{"id": "10.2113/gssgfbull.183.6.547", "title": "Paleobiogeography and biodiversity of Late Maastrichtian dinosaurs: how many dinosaur species went extinct at the Cretaceous-Tertiary boundary?", "abstract": "The global Late Maastrichtian non-avian dinosaur apparent biodiversity is extensively surveyed for the first time. It amounts to 104 species (including unnamed forms) in 2010. The real biodiversity being obscured by taphonomical biases and the scarcity of the continental fossil record, a species-area relationship is used to estimate it. The results show that several hundreds (between 628 and 1078) non-avian dinosaur species were alive in the Late Maastrichtian, which is almost an order of magnitude above previous estimates. Because of the complex Late Cretaceous palaeobiogeography, discussions about dinosaur extinction should be based on this estimated real global biodiversity, not on the apparent biodiversity of a single area. Given the mean duration of dinosaur genera (7.7 Ma), the presence of so many dinosaur species in the Latest Cretaceous is consistent with the termination of most lineages at the Cretaceous-Tertiary boundary (the Late Maastrichtian sub-stage is 2.8 m.y. long). The Late Maastrichtian dinosaurian biodiversity is therefore consistent with the sudden extinction of the group following the Chicxulub impact.", "keyphrases": ["biodiversity", "dinosaur specie", "cretaceous-tertiary boundary"]}
{"id": "10.1111/brv.12161", "title": "Permian\u2013Triassic Osteichthyes (bony fishes): diversity dynamics and body size evolution", "abstract": "The Permian and Triassic were key time intervals in the history of life on Earth. Both periods are marked by a series of biotic crises including the most catastrophic of such events, the end\u2010Permian mass extinction, which eventually led to a major turnover from typical Palaeozoic faunas and floras to those that are emblematic for the Mesozoic and Cenozoic. Here we review patterns in Permian\u2013Triassic bony fishes, a group whose evolutionary dynamics are understudied. Based on data from primary literature, we analyse changes in their taxonomic diversity and body size (as a proxy for trophic position) and explore their response to Permian\u2013Triassic events. Diversity and body size are investigated separately for different groups of Osteichthyes (Dipnoi, Actinistia, \u2018Palaeopterygii\u2019, \u2018Subholostei\u2019, Holostei, Teleosteomorpha), within the marine and freshwater realms and on a global scale (total diversity) as well as across palaeolatitudinal belts. Diversity is also measured for different palaeogeographical provinces. Our results suggest a general trend from low osteichthyan diversity in the Permian to higher levels in the Triassic. Diversity dynamics in the Permian are marked by a decline in freshwater taxa during the Cisuralian. An extinction event during the end\u2010Guadalupian crisis is not evident from our data, but \u2018palaeopterygians\u2019 experienced a significant body size increase across the Guadalupian\u2013Lopingian boundary and these fishes upheld their position as large, top predators from the Late Permian to the Late Triassic. Elevated turnover rates are documented at the Permian\u2013Triassic boundary, and two distinct diversification events are noted in the wake of this biotic crisis, a first one during the Early Triassic (dipnoans, actinistians, \u2018palaeopterygians\u2019, \u2018subholosteans\u2019) and a second one during the Middle Triassic (\u2018subholosteans\u2019, neopterygians). The origination of new, small taxa predominantly among these groups during the Middle Triassic event caused a significant reduction in osteichthyan body size. Neopterygii, the clade that encompasses the vast majority of extant fishes, underwent another diversification phase in the Late Triassic. The Triassic radiation of Osteichthyes, predominantly of Actinopterygii, which only occurred after severe extinctions among Chondrichthyes during the Middle\u2013Late Permian, resulted in a profound change within global fish communities, from chondrichthyan\u2010rich faunas of the Permo\u2010Carboniferous to typical Mesozoic and Cenozoic associations dominated by actinopterygians. This turnover was not sudden but followed a stepwise pattern, with leaps during extinction events.", "keyphrases": ["bony fish", "diversity dynamic", "predator", "early triassic", "actinopterygian"]}
{"id": "10.1098/rsta.2003.1238", "title": "The future of the carbon cycle: review, calcification response, ballast and feedback on atmospheric CO2", "abstract": "The operation of the carbon cycle forms an important part of the processes relevant to future changes in atmospheric carbon dioxide. The balance of carbon between terrestrial and oceanic reservoirs is an important factor and here we focus in particular on the oceans. Future changes in the carbon cycle that may affect air\u2013sea partitioning of CO2 are difficult to quantify but the palaeoceanographic record and modern observational studies provide important evidence of what variations might occur. These include changes in surface nutrient use, the oceanic inventory of nutrients, and the elemental composition and rain\u2013rate ratio of marine particles. Recent work has identified two inter\u2013linked processes of potential importance that we consider in some detail: the response of marine calcification to changes in surface water CO2 and the association of particulate organic carbon with ballast minerals, in particular biogenic calcite. We review evidence from corals, coccolithophores and foraminifera, which suggests that the response of reduced calcification provides a negative feedback on rising atmospheric CO2. We then use a box model to demonstrate how the calcification response may affect the organic carbon rain rate through the ballast effect. The ballast effect on export fluxes of organic and inorganic carbon acts to counteract the negative calcification response to increased CO2. Thus, two oceanic buffers exert a significant control on ocean\u2013atmosphere carbonate chemistry: the thermodynamic CO2 buffer; and the ballast/calcification buffer. Just how tightly coupled the rain\u2013rate ratio of CaCO3/Corg is to fluxes of ballast minerals is an important question for future research.", "keyphrases": ["carbon cycle", "calcification response", "atmospheric co2"]}
{"id": "10.1002/ajpa.20165", "title": "Late Pleistocene/Holocene craniofacial morphology in Mesoamerican Paleoindians: implications for the peopling of the New World.", "abstract": "Several studies on craniofacial morphology showed that most Paleoindians, who were the first settlers of the New World, clearly differ from modern Amerindians and East Asians, their supposed descendants and sister group, respectively. Here we present new evidence supporting this view from the Late Pleistocene/Early Holocene horizon from Mexico, as well as from the most complete set of dated Paleoindian remains. We analyzed the phenotypic resemblance of early Mexicans with other South Paleoamerican and modern human series. Two independent approaches to the data were used. In the first case, individual specimens were tested for morphological similarity with a set of modern reference samples. In the second analysis, Mexican specimens were treated as a sample in order to compute minimum genetic distances. Results from both approaches tend to associate early Mexican skulls with Paleoindians from Brazil, an Archaic sample from Colombia, and several circum-Pacific populations. These results give support to a model in which morphologically generalized groups of non-Northeast Asian descent (the so-called Paleoamericans) entered the continent first, and then dispersed from North to South America through Central America. The large geographic dispersal of Paleoamericans, and their presence in Mexico in the Early Holocene, raise new issues about the continent's settlement scenario.", "keyphrases": ["craniofacial morphology", "new world", "late pleistocene"]}
{"id": "10.2307/3670460", "title": "THE ECOLOGY OF LATE PLEISTOCENE AND RECENT MICROTUS FROM SOUTH-CENTRAL AND SOUTHWESTERN NEW MEXICO", "abstract": "Four species of voles (Microtus pennsylvanicus, M. mexicanus, M. mont-nus and M. ochrogaster) are reported from Late Pleistocene and Recent cave deposits in southcentral and southwestern New Mexico. Identification of isolated molars was achieved by multivariate statistics. Aspects of paleoecology for each locality are given and late pluvial to Recent conditions of southern New Mexico are discussed. Rodents of the genus Microtus have long been favorites of Pleisto- cene paleontologists because of their complex dentition and their high degree of habitat specificity. Despite voluminous literature on molar patterns and variations, most isolated microtine molars are not reliably identifiable to species. Extensive microtine remains from five caves in southcentral and southwestern New Mexico gave me the impetus to develop a new method for the identification of microtine teeth and to reconstruct aspects of late Pleistocene paleoecology in southern New Mexico based upon the identifications. METHODS. Material was taken from two previously known sites (Shelter Cave and Howell's Ridge Cave) and two new sites (The Khulo and Anthony Cave). Material from Conkling's Cavern was borrowed. Locations of sites are shown in Fig. 1. When excavated, the sizes of test pits varied from site to site, but only 10 cm levels were removed at a time unless a clearly defined layer was observed, in which case the natural stratification was followed. At each locality a general survey of the present day ecology and geology was made. Microtine material consisted of isolated teeth and some partial jaws. Modern skeletal material of five species of Microtus now living in the Southwest", "keyphrases": ["pleistocene", "microtus", "southwestern new mexico"]}
{"id": "10.7717/peerj.857", "title": "A specimen-level phylogenetic analysis and taxonomic revision of Diplodocidae (Dinosauria, Sauropoda)", "abstract": "Diplodocidae are among the best known sauropod dinosaurs. Several species were described in the late 1800s or early 1900s from the Morrison Formation of North America. Since then, numerous additional specimens were recovered in the USA, Tanzania, Portugal, and Argentina, as well as possibly Spain, England, Georgia, Zimbabwe, and Asia. To date, the clade includes about 12 to 15 nominal species, some of them with questionable taxonomic status (e.g., \u2018Diplodocus\u2019 hayi or Dyslocosaurus polyonychius), and ranging in age from Late Jurassic to Early Cretaceous. However, intrageneric relationships of the iconic, multi-species genera Apatosaurus and Diplodocus are still poorly known. The way to resolve this issue is a specimen-based phylogenetic analysis, which has been previously implemented for Apatosaurus, but is here performed for the first time for the entire clade of Diplodocidae. The analysis includes 81 operational taxonomic units, 49 of which belong to Diplodocidae. The set of OTUs includes all name-bearing type specimens previously proposed to belong to Diplodocidae, alongside a set of relatively complete referred specimens, which increase the amount of anatomically overlapping material. Non-diplodocid outgroups were selected to test the affinities of potential diplodocid specimens that have subsequently been suggested to belong outside the clade. The specimens were scored for 477 morphological characters, representing one of the most extensive phylogenetic analyses of sauropod dinosaurs. Character states were figured and tables given in the case of numerical characters. The resulting cladogram recovers the classical arrangement of diplodocid relationships. Two numerical approaches were used to increase reproducibility in our taxonomic delimitation of species and genera. This resulted in the proposal that some species previously included in well-known genera like Apatosaurus and Diplodocus are generically distinct. Of particular note is that the famous genus Brontosaurus is considered valid by our quantitative approach. Furthermore, \u201cDiplodocus\u201d hayi represents a unique genus, which will herein be called Galeamopus gen. nov. On the other hand, these numerical approaches imply synonymization of \u201cDinheirosaurus\u201d from the Late Jurassic of Portugal with the Morrison Formation genus Supersaurus. Our use of a specimen-, rather than species-based approach increases knowledge of intraspecific and intrageneric variation in diplodocids, and the study demonstrates how specimen-based phylogenetic analysis is a valuable tool in sauropod taxonomy, and potentially in paleontology and taxonomy as a whole.", "keyphrases": ["phylogenetic analysis", "diplodocidae", "north america", "apatosaurus"]}
{"id": "paleo.012128", "title": "The early Aurignacian dispersal of modern humans into westernmost Eurasia", "abstract": "Significance We report the remarkable discovery of an early Aurignacian occupation, \u223c5,000 years older than any Upper Paleolithic site in westernmost Eurasia. The archaeological and radiocarbon data provide definitive evidence that modern humans were in western Iberia at a time when, if present at all, Neanderthal populations would have been extremely sparse. This discovery has important ramifications for our understanding of the process of modern human dispersal and replacement of Neanderthal populations. The results support a very rapid, unimpeded dispersal of modern humans across western Eurasia and support the notion that climate and environmental change played a significant role in this process. Documenting the first appearance of modern humans in a given region is key to understanding the dispersal process and the replacement or assimilation of indigenous human populations such as the Neanderthals. The Iberian Peninsula was the last refuge of Neanderthal populations as modern humans advanced across Eurasia. Here we present evidence of an early Aurignacian occupation at Lapa do Picareiro in central Portugal. Diagnostic artifacts were found in a sealed stratigraphic layer dated 41.1 to 38.1 ka cal BP, documenting a modern human presence on the western margin of Iberia \u223c5,000 years earlier than previously known. The data indicate a rapid modern human dispersal across southern Europe, reaching the westernmost edge where Neanderthals were thought to persist. The results support the notion of a mosaic process of modern human dispersal and replacement of indigenous Neanderthal populations.", "keyphrases": ["dispersal", "modern human", "westernmost eurasia"]}
{"id": "10.1029/2007PA001553", "title": "Mg/Ca\u2013temperature proxy in benthic foraminifera: New calibrations from the Florida Straits and a hypothesis regarding Mg/Li", "abstract": "[1]\u00a0Over the past decade, the ratio of Mg to Ca in foraminiferal tests has emerged as a valuable paleotemperature proxy. However, large uncertainties remain in the relationships between benthic foraminiferal Mg/Ca and temperature. Mg/Ca was measured in benthic foraminifera from 31 high-quality multicore tops collected in the Florida Straits, spanning a temperature range of 5.8\u00b0 to 18.6\u00b0C. New calibrations are presented for Uvigerina peregrina, Planulina ariminensis, Planulina foveolata, and Hoeglundina elegans. The Mg/Ca values and temperature sensitivities vary among species, but all species exhibit a positive correlation that decreases in slope at higher temperatures. The decrease in the sensitivity of Mg/Ca to temperature may potentially be explained by Mg/Ca suppression at high carbonate ion concentrations. It is suggested that a carbonate ion influence on Mg/Ca may be adjusted for by dividing Mg/Ca by Li/Ca. The Mg/Li ratio displays stronger correlations to temperature, with up to 90% of variance explained, than Mg/Ca alone. These new calibrations are tested on several Last Glacial Maximum (LGM) samples from the Florida Straits. LGM temperatures reconstructed from Mg/Ca and Mg/Li are generally more scattered than core top measurements and may be contaminated by high-Mg overgrowths. The potential for Mg/Ca and Mg/Li as temperature proxies warrants further testing.", "keyphrases": ["benthic foraminifera", "new calibration", "florida straits"]}
{"id": "10.1017/S1477201907002039", "title": "Lower Ordovician (Chewtonian to Castlemainian) Radiolarians of Spitsbergen", "abstract": "Synopsis Diverse and well\u2010preserved radiolarian faunas are found in a biostratigraphically precisely dated succession in the Lower Ordovician of Spitsbergen. The faunas are from the Didymograptellus bifidus and Isograptus victoriae lunatus graptolite Biozones. They document the transition from the Upper Cambrian to Lower Ordovician spicular dominated to spumellarian dominated Middle and Upper Ordovician faunas and yield important data for a more precise biostratigraphical use of Ordovician radiolarians. The faunas are dominated by early spumellarians of the Antygoporidae and Aspiculumidae, while the Protoentactiniidae and Palaeospiculumidae are rare elements surviving from the earlier Palaeozoic. Members of the Echidninidae have not been found. The precise definition of a number of important structural characters of early Palaeozoic radiolarians is discussed. The early spumellarians of the family Antygoporidae possess a distinct microsphere formed from a number of curved bars and provided on the outside with a variable number of outer spines, representing the oldest known type of microsphere. The development of the spherical skeletons of spumellarian and entactinarian radiolarians is developed in a number of different ways that are important for phylogen\u2010etic considerations. The following taxa are new: Svalbardospiculum gen. nov., Svalbardospiculum arenigium sp. nov., Protoentactinia bifurcata sp. nov., Sphaeroentactiniidae fam. nov.,Sphaeroentac\u2010tinia gen. nov., S. hexaspinosa sp. nov., S. bispinosa sp. nov., S. integrata sp. nov., Nyfrieslandia gen. nov., N. sphaeroidea sp. nov., N. complicata sp. nov., Parechidnina densa sp. nov., Antygoporidae fam. nov., Antygopora bella sp. nov., A. compacta sp. nov., A. microspina sp. nov., A. labyrinthina sp. nov., Labyrinthia gen. nov., Labyrinthia inexpectata sp. nov.", "keyphrases": ["radiolarians", "spitsbergen", "radiolarian faunas", "upper cambrian", "low ordovician"]}
{"id": "paleo.008293", "title": "Bivalve network reveals latitudinal selectivity gradient at the end-Cretaceous mass extinction", "abstract": "Biogeographic patterns of survival help constrain the causal factors responsible for mass extinction. To test whether biogeography influenced end-Cretaceous (K-Pg) extinction patterns, we used a network approach to delimit biogeographic units (BUs) above the species level in a global Maastrichtian database of 329 bivalve genera. Geographic range is thought to buffer taxa from extinction, but the number of BUs a taxon occurred in superseded geographic range as an extinction predictor. Geographically, we found a latitudinal selectivity gradient for geographic range in the K-Pg, such that higher latitude BUs had lower extinction than expected given the geographic ranges of the genera, implying that (i) high latitude BUs were more resistant to extinction, (ii) the intensity of the K-Pg kill mechanism declined with distance from the tropics, or (iii) both. Our results highlight the importance of macroecological structure in constraining causal mechanisms of extinction and estimating extinction risk of taxa.\nass extinctions have disproportionately shaped the evolutionary history of life 1 . During these rare, geologically rapid events, the rules of selectivity that prevail in background extinctions do not always clearly apply 2 . To delimit what may be independent selection processes and constrain possible causal factors, paleontologists have sought biologically meaningful patterns of survivorship in mass extinctions 3, 4 . In the marine realm, there are some taxon-specific cases where survivorship is linked to ecological traits -for example, in the K-Pg mass extinction event, reliance on photosymbiosis among scleractinian corals severely reduced survivorship 5 and sea urchin feeding strategy correlates positively with survivorship 6 . However, more often, survivorship in mass extinctions appears to be linked to increased geographic range size above the species level 7 , suggesting that biogeographic history of a taxon plays a vital role in sorting survivors from victims.\nThe correlation of geographic range at the lineage level with lineage survival, but apparent lack of physiological mechanisms in determining survivorship, suggests that lineages with similar biogeographic histories should have similar chances to survive mass extinction. Histories of ocean surface currents, plate tectonics, and environments shape biogeographic patterns above the species level by allowing lineages (genera) dispersal opportunities. Here, we explore whether these emergent biogeographic regions impact our understanding of extinction processes.\nHere we employ a network approach to test whether biogeographic structure above the species level 8-11 correlates with bivalve survivorship in the K-Pg. Network methods have been useful in a broad range of applications, for example, to model the transmission of disease in social networks 12 , to describe the structure of scholarly communication 13 , and to model the stability of ecosystems in response to extinction 14 . A network approach can also reveal spatial patterns of taxa from geographic range data 15 . We generated a Maastrichtian network from the bivalve dataset, and used stratigraphic ranges from the Paleobiology Database to determine which genera survived the K-Pg mass extinction event 16 . We adapt a network-based clustering approach 13 to reveal biogeographic units (BUs) from patterns of geographic ranges (see methods).\nThe K-Pg event (ca. 66 Ma) is an ideal case to test whether biogeography influences survival in mass extinctions. It was geologically abrupt and was associated with significant changes to marine productivity and ocean chemistry, dramatic restructuring of marine and terrestrial communities, long-term effects on evolutionary rates and biogeography 17, 18 , and the extinction of up to 76% of all species 19 . As the most recent of the ''big five'' mass extinctions, the quantity, quality, and spatial resolution of the geological and paleontological data for the K-Pg interval are also better than those available for more ancient mass extinctions 22 . Bivalves have emerged as a model", "keyphrases": ["latitudinal selectivity gradient", "mass extinction", "survival", "network approach", "unit"]}
{"id": "10.1029/95pa00059", "title": "A model for variation in the chemistry of planktonic foraminifera due to secondary calcification and selective dissolution", "abstract": "A quantitative model for describing the within-population variation in planktonic foraminifer shell chemistry that results from secondary calcification and selective dissolution is presented. The objective is to construct a basis for inferring the chemistries of different shell components and estimating the extent of shell dissolution. Variation is modeled as mixtures of two kinds of shell calcite, a primary calcite that forms the chambers and a secondary calcite that forms crust. Bulk shell chemistries are intermediate between the chemistries of these calcites and lie on mixing lines between them. For two component systems, mass balance relationships can be reformulated as a linear regression and solved for the chemistries of the primary and secondary calcites and for the uncertainties associated with these estimates. To apply this model, one needs measurements of bulk shell chemistries and estimates of the relative proportions of secondary and primary calcites. For most planktonic foraminifer species the proportion of secondary calcite can be estimated from differences in the relationship between shell size and mass before and after crusting. Preliminary results are consistent with previous work showing that secondary calcites are added at depth. However, even deep-dwelling species appear to grow most of their primary shell in surface waters and some surface-dwelling species add secondary calcite in the deep ocean. In contrast to the model's simple description of secondary calcification, the variation in chemistry from selective dissolution is more complicated because undissolved shells are themselves mixtures of primary and secondary calcites and therefore present a wide range of initial shell compositions. Nevertheless, the model allows both the compositions of different components to be inferred and the amount of dissolution to be estimated. Preliminary results indicate that dissolution of planktonic foraminifera is apparent nearly 2 km above the foraminifer lysocline and even apparently well-preserved shells may be over 50% dissolved.", "keyphrases": ["planktonic foraminifera", "secondary calcification", "selective dissolution"]}
{"id": "10.1073/pnas.1011553108", "title": "Genetic evidence for patrilocal mating behavior among Neandertal groups", "abstract": "The remains of 12 Neandertal individuals have been found at the El Sidr\u00f3n site (Asturias, Spain), consisting of six adults, three adolescents, two juveniles, and one infant. Archaeological, paleontological, and geological evidence indicates that these individuals represent all or part of a contemporaneous social group of Neandertals, who died at around the same time and later were buried together as a result of a collapse of an underground karst. We sequenced phylogenetically informative positions of mtDNA hypervariable regions 1 and 2 from each of the remains. Our results show that the 12 individuals stem from three different maternal lineages, accounting for seven, four, and one individual(s), respectively. Using a Y-chromosome assay to confirm the morphological determination of sex for each individual, we found that, although the three adult males carried the same mtDNA lineage, each of the three adult females carried different mtDNA lineages. These findings provide evidence to indicate that Neandertal groups not only were small and characterized by low genetic diversity but also were likely to have practiced patrilocal mating behavior.", "keyphrases": ["patrilocal mating behavior", "neandertal group", "genetic evidence"]}
{"id": "paleo.004467", "title": "First spalacotheriid and dryolestid mammals from the Cretaceous of Germany", "abstract": "The new spalacotheriid \u201csymmetrodontan\u201d Cifellitherium suderlandicum gen. et sp. nov. from the Barremian\u2013Aptian of the Balve locality in northwestern Germany is the first record of spalacotheriids in Central Europe. The new taxon is based on one lower and two upper molars. Cifellitherium is similar to Spalacotherium, but differs by smaller stylocone and larger paraststyle on the upper molars, and a labially interrupted cingulid on the lower molar. The new dryolestid Minutolestes submersus gen. et sp. nov. is based on one lower and two upper molars of small size. Phylogenetic analysis revealed it as sister taxon of the clade comprising Laolestes, Krebsotherium, Dryolestes, and Guimarotodus. A dryolestid mandible with unevenly rooted molars and extremely worn down teeth cannot be attributed to Minutolestes submersus gen. et sp. nov. due to possessing molars twice as large in size. The mandible is assigned to a new dryolestid taxon, Beckumia sinemeckelia gen. et sp. nov., and has the dental formula 3i, 1c, 4p, 8m and a fully reduced Meckel\u2019s groove. The mandible lacks any trace of a coronoid or splenial. In the phylogenetic analysis, it appears as sister taxon of a clade comprising Achyrodon, Phascolestes, Crusafontia, and Hercynodon. The new mammals are the stratigraphically youngest European representatives of their clades. The late survival of Beckumia sinemeckelia gen. et sp. nov. and Minutolestes submersus gen. et sp. nov. is possibly the result of isolated evolution in an Early Cretaceous island environment. This finding of new spalacotheriid and dryolestid mammals from Central Europe adds to an emerging paleobiogeographic pattern that Europe was distinct from Asia in the constituents of mammalian faunas during the Barremian\u2013Aptian.", "keyphrases": ["spalacotheriid", "dryolestid mammal", "germany"]}
{"id": "10.1080/02724634.2017.1306536", "title": "The Earliest-Known Fin Whale, Balaenoptera physalus, from the Early Pleistocene of Northern California, U.S.A.", "abstract": "Citation for this article: Tsai, C.-H., and R. W. Boessenecker. 2017. The earliest-known fin whale, Balaenoptera physalus, from the Early Pleistocene of Northern California, U.S.A. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1306536.", "keyphrases": ["earliest-known fin whale", "balaenoptera physalus", "pleistocene"]}
{"id": "10.1029/94PA00292", "title": "Variations in the strontium isotopic ratio of seawater during the Miocene: Stratigraphic and geochemical implications", "abstract": "A composite strontium isotopic seawater curve was constructed for the Miocene between 24 and 6 Ma by combining 87Sr/86Sr measurements of planktonic foraminifera from Deep Sea Drilling Project sites 289 and 588. Site 289, with its virtually continuous sedimentary record and high sedimentation rates (26 m/m.y.), was used for constructing the Oligocene to mid-Miocene part of the record, which included the calibration of 63 biostratigraphic datums to the Sr seawater curve using the timescale of Cande and Kent (1992). Across the Oligocene/Miocene boundary, a brief plateau occurred in the Sr seawater curve (87Sr/86Sr values averaged 0.70824) which is coincident with a carbon isotopic maximum (CM-O/M) from 24.3 to 22.6 Ma. During the early Miocene, the strontium isotopic curve was marked by a steep rise in 87Sr/86Sr that included a break in slope near 19 Ma. The rate of growth was about 60 ppm/m.y. between 22.5 and 19.0 Ma and increased to over 80 ppm/m.y. between 19.0 and 16 Ma. Beginning at \u223c16 Ma (between carbon isotopic maxima CM3 and CM4 of Woodruff and Savin (1991)), the rate of 87Sr/86Sr growth slowed and 87Sr/86Sr values were near constant from 15 to 13 Ma. After 13 Ma, growth in 87Sr/86Sr resumed and continued until \u223c9 Ma, when the rate of 87Sr/86Sr growth decreased to zero once again. The entire Miocene seawater curve can be described by a high-order function, and the first derivative (d87Sr/86Sr/dt) of this function reveals two periods of increased slope. The greatest rate of 87Sr/86Sr change occurred during the early Miocene between \u223c20 and 16 Ma, and a smaller, but distinct, period of increased slope also occurred during the late Miocene between \u223c12 and 9 Ma. These periods of steepened slope coincide with major phases of uplift and denudation of the Himalayan-Tibetan Plateau region, supporting previous interpretations that the primary control on seawater 87Sr/86Sr during the Miocene was related to the collision of India and Asia. The rapid increase in 87Sr/86Sr values during the early Miocene from 20 to 16 Ma imply high rates of chemical weathering and dissolved riverine fluxes to the oceans. In the absence of another source of CO2, these high rates of chemical weathering should have quickly resulted in a drawdown of atmospheric CO2 and climatic cooling through a reversed greenhouse effect. The paleoclimatic record, however, indicates a warming trend during the early Miocene, culminating in a climatic optimum between 17 and 14.5 Ma. We suggest that the high rates of chemical erosion and warm temperatures during the climatic optimum were caused by an increase in the contribution of volcanic CO2 from the eruption of the Columbia River Flood Basalts (CRFB) between 17 and 15 Ma. The decrease in the rate of CRFB eruptions at 15 Ma and the removal of atmospheric carbon dioxide by increased organic carbon burial in Monterey deposits eventually led to cooling and increased glaciation between \u223c14.5 and 13 Ma. The CRFB hypothesis helps to explain the significant time lag between the onset of increased rates of organic carbon burial in the Monterey at 17.5 Ma (as marked by increased \u03b413C values) and the climatic cooling and glaciation during the middle Miocene (as marked by the increase in \u03b418O values), which did not begin until \u223c14.5 Ma.", "keyphrases": ["strontium", "seawater", "miocene"]}
{"id": "10.1111/j.1502-3931.2011.00277.x", "title": "Preliminary assessment of the use of electron backscatter diffraction (EBSD) in conodonts", "abstract": "Perez-Huerta, A., Cusack, M. & Mendez, C.A. 2011: Preliminary assessment of the use of electron backscatter diffraction (EBSD) in conodonts. Lethaia, Vol. 45, pp. 253\u2013258. \n \n \n \nConodonts are extensively used as \u2018geochemical tools\u2019 in palaeoenvironmental reconstructions in Palaeozoic and Triassic strata. The retention of a primary geochemical signal is substantially dependent on the ultrastructural integrity and crystallinity after diagenesis. Direct assessments of the preservation potential of the polycrystalline matrix are scarce with the exception of the application of transmission electron microscopy (TEM). The possible application of electron backscatter diffraction (EBSD) is introduced for well-preserved Pennsylvanian platform conodont elements as a novel in situ technique based on successful previous results for biogenic carbonates. EBSD shows the presence of no diffraction in central regions of all studied elements of Idiognathodus and Adetognathus, with possible implications for geochemistry analysis. The absence of diffraction could be attributed to the existence of an amorphous phase, water (+OH) or a process of hypocalcification related to the development of \u2018growth cavities\u2019 in the lamellar crown tissue. Overall results indicate the suitability of using EBSD to extract crystallographic information from conodonts and potentially for other apatite (micro-) fossils. \u25a1Conodont, diagenesis, EBSD, geochemistry, Pennsylvanian.", "keyphrases": ["assessment", "electron backscatter diffraction", "conodont"]}
{"id": "10.1111/1755-0998.13162", "title": "An optimized method for the extraction of ancient eukaryote DNA from marine sediments", "abstract": "Marine sedimentary ancient DNA (sedaDNA) provides a powerful means to reconstruct marine palaeo\u2010communities across the food web. However, currently there are few optimized sedaDNA extraction protocols available to maximize the yield of small DNA fragments typical of ancient DNA (aDNA) across a broad diversity of eukaryotes. We compared seven combinations of sedaDNA extraction treatments and sequencing library preparations using marine sediments collected at a water depth of 104 m off Maria Island, Tasmania, in 2018. These seven methods contrasted frozen versus refrigerated sediment, bead\u2010beating induced cell lysis versus ethylenediaminetetraacetic acid (EDTA) incubation, DNA binding in silica spin columns versus in silica\u2010solution, diluted versus undiluted DNA in shotgun library preparations to test potential inhibition issues during amplification steps, and size\u2010selection of low molecular\u2010weight (LMW) DNA to increase the extraction efficiency of sedaDNA. Maximum efficiency was obtained from frozen sediments subjected to a combination of EDTA incubation and bead\u2010beating, DNA binding in silica\u2010solution, and undiluted DNA in shotgun libraries, across 45 marine eukaryotic taxa. We present an optimized extraction protocol integrating these steps, with an optional post\u2010library LMW size\u2010selection step to retain DNA fragments of \u2264500 base pairs. We also describe a stringent bioinformatic filtering approach for metagenomic data and provide a comprehensive list of contaminants as a reference for future sedaDNA studies. The new extraction and data\u2010processing protocol should improve quantitative paleo\u2010monitoring of eukaryotes from marine sediments, as well as other studies relying on the detection of highly fragmented and degraded eukaryote DNA in sediments.", "keyphrases": ["extraction", "eukaryote dna", "marine sediment"]}
{"id": "10.1130/B26568.1", "title": "A complete magnetic-polarity stratigraphy of the Miocene continental deposits of Mae Moh Basin, northern Thailand, and a reassessment of the age of hominoid-bearing localities in northern Thailand", "abstract": "Northern Thailand comprises more than 40 Tertiary intermontane basins. These basins, tectonically interpreted as grabens or half grabens, have yielded hominoid fossils and rich Neogene mammal faunas. Relative ages provided by biochronological studies are controversial and neither absolute ages nor correlations with marine deposits are available. A precise temporal framework provided by magnetic-polarity stratigraphy is therefore crucial to understand the evolution of these Southeast Asian mammalian faunas, to estimate the timing and duration of basin formation, and finally to allow correlations with other Neogene hominoid localities of the Old World. A complete magnetostratigraphic study, which significantly extends previous paleomagnetic investigations, has been conducted in the Miocene sequence of Mae Moh Basin, Lampang Province, northern Thailand. Based on the biostratigraphic constraints, the 15 polarity zones recognized from the composite section have been correlated with Chrons C5ACr\u2013C5r.3r, between 14.1 and 12.0 Ma. The present study provides a high-resolution magnetostratigraphic reference for the continental middle Miocene of all Southeast Asia. By correlation with the Miocene sequence of the nearby basin of Chiang Muan, the large-bodied hominoid ( Khoratpithecus chiangmuanensis )\u2013bearing levels can be precisely dated between 12.4 and 12.2 Ma.", "keyphrases": ["magnetic-polarity stratigraphy", "mae moh basin", "northern thailand"]}
{"id": "paleo.000063", "title": "Knoetschkesuchus langenbergensis gen. nov. sp. nov., a new atoposaurid crocodyliform from the Upper Jurassic Langenberg Quarry (Lower Saxony, northwestern Germany), and its relationships to Theriosuchus", "abstract": "We report a new, small-sized atoposaurid crocodyliform from the Upper Jurassic of Langenberg, Northeastern Germany. Atoposaurids are small-sized Mesozoic crocodyliforms of mainly European distribution, which are considered to be phylogenetically close to the origin of Eusuchia. Knoetschkesuchus langenbergensis gen. nov. sp. nov. is represented by two well-preserved skulls and additional cranial and postcranial remains representing different ontogenetic stages. 3D reconstructions of a juvenile skull based on micro-computed tomography allow the most detailed description of cranial remains of any atoposaurid hitherto presented. Our new analysis contradicts previous preliminary assignment of the Langenberg atoposaurids to Theriosuchus. Knoetschkesuchus gen. nov. is characterized in particular by the presence of two dental morphotypes in the maxilla and dentary, slit-like secondary choanae within a narrow groove on the surface of the pterygoid, absence of lacrimonasal contact, presence of an antorbital foramen and an external mandibular fenestra, and proportional characters of the interorbital and intertemporal region. A similar combination of characters allows attribution of Theriosuchus guimarotae to Knoetschkesuchus, forming the new combination Knoetschkesuchus guimarotae. Our analysis provides an osteological basis for the separation of Theriosuchus and Knoetschkesuchus and helps further delineate generic differences in other closely related crocodylomorphs. Our phylogenetic analysis corroborates inclusion of Knoetschkesuchus into Atoposauridae and supports a position of Atoposauridae within Eusuchia.", "keyphrases": ["atoposaurid crocodyliform", "theriosuchus", "knoetschkesuchus langenbergensis gen"]}
{"id": "paleo.008857", "title": "Cladistic tests of monophyly and relationships of biostratigraphically significant conodonts using multielement skeletal data \u2013Lochriea homopunctatus and the genus Lochriea", "abstract": "Abstract:\u2002 Since the 1960s, huge progress has been made in reconstructing the multielement skeletons of conodont species and developing a biologically defensible taxonomy. Nevertheless, a widespread prejudice remains that certain parts of the conodont skeleton, particularly the P1 elements, are more informative than others with regard to taxonomy and evolutionary relationships. Here, we test these views. A new partial multielement reconstruction of the skeleton of the biostratigraphically significant conodont originally described as Gnathodus commutatus homopunctatus allows us to conduct a cladistic test of the alternative hypotheses of phylogenetic placement of this species. Our analysis also provides the first test of the hypothesis that Lochriea\u2013 species of which are markers for global correlation \u2013 is monophyletic and tests hypotheses concerning the origins of the genus. Our results demonstrate that homopunctatus is a species of Lochriea and that the genus is monophyletic. The widely held view that Lochriea arose from a species of Bispathodus is not supported. Our results show that it is difficult to predict a priori which parts of the conodont skeleton carry phylogenetic signal, and provide strong support for the hypothesis that similarity in the morphology of conodont P1 elements alone is not a reliable guide to relationships and taxonomic groupings of conodont species. This is because P1 elements with similar morphologies are convergently acquired in multiple conodont clades, because reliance on the characters of only one of the six or seven morphologically distinct elements of the conodont skeleton ignores phylogenetically significant data and because P1 elements can lack characters that might seem to be diagnostic of a genus. Conodonts are no different to other organisms: ignoring data that have the potential to be phylogenetically informative is unlikely to produce the most reliable hypotheses of evolutionary relationships. We suggest that other biostratigraphically significant hypotheses of relationship between conodont taxa that are based on P1 elements alone should be subject to cladistic testing.", "keyphrases": ["conodont", "homopunctatus", "cladistic test"]}
{"id": "paleo.012838", "title": "Extreme weather events recorded by daily to hourly resolution biogeochemical proxies of marine giant clam shells", "abstract": "Significance Reconstructing past extreme weather events, such as tropical cyclones and cold surges, using natural paleoclimate archives can lengthen the instrumental data and help us have a broader understanding of the range of weather variability not evident in instrumental record. However, the time resolution of current paleoarchives, from millennial to monthly at best, is usually too low to explore past weather events. Here we found that the Tridacna shells from South China Sea, western Pacific, have continuous daily growth bands, and several daily to hourly resolution biogeochemical proxy records were developed. Our results demonstrate that these records can record nearby tropical cyclones and cold surges, indicating that Tridacna shells have the potential to be an unprecedented ultra-high-resolution archive for paleoweather reconstructions. Paleoclimate research has built a framework for Earth\u2019s climate changes over the past 65 million years or even longer. However, our knowledge of weather-timescale extreme events (WEEs, also named paleoweather), which usually occur over several days or hours, under different climate regimes is almost blank because current paleoclimatic records rarely provide information with temporal resolution shorter than monthly scale. Here we show that giant clam shells (Tridacna spp.) from the tropical western Pacific have clear daily growth bands, and several 2-y-long (from January 29, 2012 to December 9, 2013) daily to hourly resolution biological and geochemical records, including daily growth rate, hourly elements/Ca ratios, and fluorescence intensity, were obtained. We found that the pulsed changes of these ultra-high-resolution proxy records clearly matched with the typical instrumental WEEs, for example, tropical cyclones during the summer\u2212autumn and cold surges during the winter. When a tropical cyclone passes through or approaches the sampling site, the growth rate of Tridacna shell decreases abruptly due to the bad weather. Meanwhile, enhanced vertical mixing brings nutrient-enriched subsurface water to the surface, resulting in a high Fe/Ca ratio and strong fluorescence intensity (induced by phytoplankton bloom) in the shell. Our results demonstrate that Tridacna shell has the potential to be used as an ultra-high-resolution archive for paleoweather reconstructions. The fossil shells living in different geological times can be built as a Geological Weather Station network to lengthen the modern instrumental data and investigate the WEEs under various climate conditions.", "keyphrases": ["resolution", "giant clam shell", "daily growth band", "biogeochemical proxy record", "extreme weather event"]}
{"id": "paleo.011056", "title": "Canadia spinosa and the early evolution of the annelid nervous system", "abstract": "Exceptional fossils reveal annelid nervous system evolution. Annelid worms are a disparate, primitively segmented clade of bilaterians that first appear during the early Cambrian Period. Reconstructing their early evolution is complicated by the extreme morphological diversity in early diverging lineages, rapid diversification, and sparse fossil record. Canadia spinosa, a Burgess Shale fossil polychaete, is redescribed as having palps with feeding grooves, a dorsal median antenna and biramous parapodia associated with the head and flanking a ventral mouth. Carbonaceously preserved features are identified as a terminal brain, circumoral connectives, a midventral ganglionated nerve cord and prominent parapodial nerves. Phylogenetic analysis recovers neuroanatomically simple extant taxa as the sister group of other annelids, but the phylogenetic position of Canadia suggests that the annelid ancestor was reasonably complex neuroanatomically and that reduction of the nervous system occurred several times independently in the subsequent 500 million years of annelid evolution.", "keyphrases": ["early evolution", "nervous system", "canadia spinosa"]}
{"id": "paleo.002741", "title": "Quantifying intra- and interspecific variability in trilobite moulting behaviour across the Palaeozoic", "abstract": "Moulting of a protective exoskeleton is a defining characteristic of Euarthropoda, and its evolution can be explored through analysing moults preserved in the fossil record. Our most complete record comes from the Trilobita, which were uniquely flexible in moulting compared to other arthropod groups. This study presents the first broad-scale quantitative analysis of trilobite moulting. Trends in moulting variability with taxonomy and through the Palaeozoic are explored by looking at the occurrences of six moulting characteristics: opening of the facial and ventral sutures; and disarticulation of the cephalon, cranidium, thorax, and pygidium. Significant differences in moulting across taxonomic and temporal groups were identified using chi-squared analyses, and biases with sampling and diversity identified through correlation analyses. Occurrences of facial and ventral suture opening, and cephalic disarticulation, significantly varied between orders and Epochs. These likely result from the prevalence of ventral suture moulting in Redlichiida and cephalic disarticulation in Phacopida, and their relevant diversity patterns. The data show high levels of intraspecific variability in moulting; ~40% of species showed multiple moulting characteristics. Redlichiida and the early Cambrian are the most intraspecifically variable, with greater variability likely an adaptation to the initial radiation and establishment of trilobites into new niches. The longest-lived group, Proetida, showed the lowest levels of intraspecific variability, which may suggest greater specialism later in the Palaeozoic. Ultimately, datasets such as this advocate the need to study behaviours in the fossil record on a broad-scale, because they help us build a comprehensive picture of extinct groups as living animals. Harriet B. Drage. Department of Zoology, University of Oxford, South Parks Road, Oxford, United Kingdom, OX1 3PS. harriet.drage@zoo.ox.ac.uk", "keyphrases": ["trilobite", "behaviour", "palaeozoic", "exoskeleton", "cephalon"]}
{"id": "10.1111/j.1096-3642.2010.00655.x", "title": "An unusual new archosauriform from the Middle\u2013Late Triassic of southern Brazil and the monophyly of Doswelliidae", "abstract": "Until now the Doswelliidae was considered a monospecific family including Doswellia kaltenbachi from the Late Triassic of North America. The phylogenetic position of this taxon remained enigmatic until recently, when a sister-group relationship with the Proterochampsidae was suggested. In the present contribution we describe the new doswelliid species Archeopelta arborensis gen. et sp. nov. from the Middle\u2013Late Triassic of Brazil. A cladistic analysis recovered Archeopelta, Doswellia, and Tarjadia within a monophyletic group of basal archosauriforms, the Doswelliidae. The monophyly of this family is supported by the presence of osteoderm ornamentation that is coarse, incised, and composed of regular pits and the presence of an unornamented anterior articular lamina. Archeopelta is more closely related to Doswellia than to other archosauriforms by the presence of basipterygoid processes anterolaterally orientated, dorsal centra with a convex surface, width of the neural arch plus ribs of the first primordial sacral that are three times the length of the neural arch, and iliac blade laterally deflected, with strongly convex dorsal margin, and a length less than three times its height. The phylogenetic analysis indicates that Doswellidae is the closest large monophyletic entity to Archosauria, which achieved a wide palaeolatitudinal distribution during the late Middle and Late Triassic time span. \n \n \n \n\u00a9 2011 The Linnean Society of London, Zoological Journal of the Linnean Society, 2011, 161, 839\u2013871.", "keyphrases": ["archosauriform", "middle\u2013late triassic", "monophyly"]}
{"id": "paleo.011048", "title": "Mid-Cretaceous amber fossils illuminate the past diversity of tropical lizards", "abstract": "Exquisitely preserved fossil lizards from 99-million-year-old Burmese amber provide new insights into paleotropical diversity. Modern tropical forests harbor an enormous diversity of squamates, but fossilization in such environments is uncommon and little is known about tropical lizard assemblages of the Mesozoic. We report the oldest lizard assemblage preserved in amber, providing insight into the poorly preserved but potentially diverse mid-Cretaceous paleotropics. Twelve specimens from the Albian-Cenomanian boundary of Myanmar (99 Ma) preserve fine details of soft tissue and osteology, and high-resolution x-ray computed tomography permits detailed comparisons to extant and extinct lizards. The extraordinary preservation allows several specimens to be confidently assigned to groups including stem Gekkota and stem Chamaleonidae. Other taxa are assignable to crown clades on the basis of similar traits. The detailed preservation of osteological and soft tissue characters in these specimens may facilitate their precise phylogenetic placement, making them useful calibration points for molecular divergence time estimates and potential keys for resolving conflicts in higher-order squamate relationships.", "keyphrases": ["lizard", "burmese amber", "vertebrate"]}
{"id": "10.1111/j.1365-3091.1986.tb00540.x", "title": "The St George Group (Lower Ordovician) of western Newfoundland: tidal flat island model for carbonate sedimentation in shallow epeiric seas", "abstract": "The St George Group consists of peritidal carbonate rocks deposited on the continental shelf of North America bordering the ancient Iapetus Ocean. These Lower Ordovician rocks are similar to other lower Palaeozoic limestones and dolostones that accumulated in epeiric seas and veneer cratonic areas worldwide. A wide variety of facies in the St George is grouped into seven lithotopes, interpreted to represent supratidal, intertidal and shallow, high- and low-energy subtidal environments. Rapid lateral facies changes can be observed in some field exposures, and demonstrated by correlation of closely spaced sections. The stratigraphic array of these lithotopes, although too irregular to be simplified into shallowing-upward cycles, suggests that they were deposited as small tidal flat islands and banks. Shallow subtidal areas around islands generated sediment and permitted tidal exchange. Tidal flat islands were somewhat variable in character at any one time, and evolved with changing regional hydrographic conditions. \n \n \n \nThe St George rocks suggest an alternative theory of carbonate sedimentation in large, shallow epeiric seas, namely as small islands and banks built by processes that operated in a tidal regime. Furthermore, this island model provides a framework for a mechanism of cyclic carbonate sedimentation, by which small-scale, peritidal cycles represent tidal flat islands that accreted vertically and migrated laterally as local sediment supply from neighbouring subtidal areas waxed and waned during relatively constant subsidence.", "keyphrases": ["island model", "carbonate sedimentation", "shallow epeiric sea"]}
{"id": "paleo.009582", "title": "The early hunting dog from Dmanisi with comments on the social behaviour in Canidae and hominins", "abstract": "The renowned site of Dmanisi in Georgia, southern Caucasus (ca. 1.8 Ma) yielded the earliest direct evidence of hominin presence out of Africa. In this paper, we report on the first record of a large-sized canid from this site, namely dentognathic remains, referable to a young adult individual that displays hypercarnivorous features (e.g., the reduction of the m1 metaconid and entoconid) that allow us to include these specimens in the hypodigm of the late Early Pleistocene species Canis (Xenocyon) lycaonoides. Much fossil evidence suggests that this species was a cooperative pack-hunter that, unlike other large-sized canids, was capable of social care toward kin and non-kin members of its group. This rather derived hypercarnivorous canid, which has an East Asian origin, shows one of its earliest records at Dmanisi in the Caucasus, at the gates of Europe. Interestingly, its dispersal from Asia to Europe and Africa followed a parallel route to that of hominins, but in the opposite direction. Hominins and hunting dogs, both recorded in Dmanisi at the beginning of their dispersal across the Old World, are the only two Early Pleistocene mammal species with proved altruistic behaviour towards their group members, an issue discussed over more than one century in evolutionary biology.", "keyphrases": ["hunting dog", "behaviour", "hominin"]}
{"id": "10.1017/jpa.2015.48", "title": "Diversity of pseudo-toothed birds (Pelagornithidae) from the Eocene of Antarctica", "abstract": "Abstract. \n The Antarctic pelagornithid record is restricted to few isolated remains from the Eocene of Seymour Island in the Antarctic Peninsula. Here we report the oldest Antarctic pseudo-toothed bird. It is represented by an incomplete humerus lacking its proximal end, which comes from the lower Eocene levels of the La Meseta Formation (Seymour Island). This new specimen facilitates a review of all known pelagornithids from this continent. Antarctic pelagornithids were classified into two morphotypes that exhibit a mix of putative plesiomorphic and derived characters. Considering the worldwide pelagornithid record and according to estimated wingspans, four approximate size-types were identified. The oldest Antarctic specimens (two fragmentary humeri, middle Ypresian) were assigned to morphotype 1 and correspond to the large size-type. The younger materials (Bartonian/?Priabonian) here assigned to morphotype 2 (some cranial remains, fragmentary tarsometatarsus and humerus) correspond to the giant size-type and represent one of the largest known pseudo-toothed birds. Even though species level phylogenetic affinities of Pelagornithidae remain poorly resolved, three key evolutionary events can be recognized: (1) the disappearance of Dasornis in the Early Eocene and the appearance of more advanced forms with a trend to the specialization of large soaring capacity, (2) the origin of Pelagornis sensu lato species in the early Oligocene, and (3) the appearance and dominance of a highly specialized terminal group at Mio/Pliocene time span.", "keyphrases": ["pseudo-toothed bird", "pelagornithidae", "antarctica"]}
{"id": "10.1098/rstb.2021.0039", "title": "Aposematic coloration from Mid-Cretaceous Kachin amber", "abstract": "Aposematic coloration is among the most diverse antipredator strategies, which can signal unpleasantness of organisms to potential predators and reduce the probability of predation. Unlike mimesis, aposematic coloration allows organisms to warn their predators away by conspicuous and recognizable colour patterns. However, aposematism has been a regular puzzle, especially as the long-term history of such traits is obscured by an insufficient fossil record. Here, we report the discovery of aposematic coloration in an orthopteran nymph from Mid-Cretaceous Kachin amber (99 million years old). It is attributed to the extinct family Elcanidae and erected as a new genus identified by conspicuous dark/light-striped coloration, four apical spurs on the metatibia, a two-segmented metatarsus and unsegmented stylus. It represents the first fossil orthopteran preserved with aposematic coloration from the Mesozoic, demonstrating that orthopterans had evolved aposematism by the Mid-Cretaceous. Our findings provide novel insights into the early evolution of anti-predator strategies among orthopterans. Together with mimesis, debris-carrying camouflage and aposematism previously reported, our findings demonstrate the relative complexity of prey\u2013predator interactions in the Mesozoic, especially in the Mid-Cretaceous Kachin amber forest. This article is part of the theme issue \u2018The impact of Chinese palaeontology on evolutionary research\u2019.", "keyphrases": ["coloration", "mid-cretaceous kachin amber", "aposematic coloration"]}
{"id": "10.1080/02724634.2019.1716778", "title": "A New Fairy Armadillo (Cingulata, Chlamyphorinae) from the Upper Miocene of Argentina: First Fossil Record of the Most Enigmatic Xenarthra", "abstract": "ABSTRACT Recent molecular analyses suggest that the evolutionary history of Cingulata (Xenarthra) could be more complex than believed previously. An ancient divergence was proposed for armadillos, recognizing two large monophyletic groups: Dasypodidae (including Dasypodinae) and Chlamyphoridae (including Euphractinae, Tolypeutinae, and Chlamyphorinae). Extant Chlamyphorinae (fairy armadillos) are among the most bizarre, elusive, and unknown mammals of the world. Here, we report the first accurate fossil record of this enigmatic xenarthran from the upper Miocene of the Argentine Pampas in southern South America, which represents a new genus and species (Chlamyphractus dimartinoi, gen. et sp. nov.). The phylogenetic analysis reflects the monophyly of the chlamyphorines. It is well supported by several unambiguous synapomorphies and includes the new fossil taxon as a sister group of the two extant species. This new taxon represents the most basal lineage among Chlamyphorinae and increases its diversity. The morphology of the forelimb suggests that it would have been a good digger, although, unlike extant species, it would not have had \u2018fully\u2019 subterranean habits.", "keyphrases": ["cingulata", "chlamyphorinae", "upper miocene"]}
{"id": "paleo.010546", "title": "Biomechanical simulations reveal a trade-off between adaptation to glacial climate and dietary niche versatility in European cave bears", "abstract": "Biomechanical simulations show a \u201ctrade-off\u201d between hibernation length and a restricted herbivorous diet for European cave bears. The cave bear is one of the best known extinct large mammals that inhabited Europe during the \u201cIce Age,\u201d becoming extinct \u224824,000 years ago along with other members of the Pleistocene megafauna. Long-standing hypotheses speculate that many cave bears died during their long hibernation periods, which were necessary to overcome the severe and prolonged winters of the Last Glacial. Here, we investigate how long hibernation periods in cave bears would have directly affected their feeding biomechanics using CT-based biomechanical simulations of skulls of cave and extant bears. Our results demonstrate that although large paranasal sinuses were necessary for, and consistent with, long hibernation periods, trade-offs in sinus-associated cranial biomechanical traits restricted cave bears to feed exclusively on low energetic vegetal resources during the predormancy period. This biomechanical trade-off constitutes a new key factor to mechanistically explain the demise of this dominant Pleistocene megafaunal species as a direct consequence of climate cooling.", "keyphrases": ["trade-off", "cave bear", "long hibernation period", "skull", "biomechanical simulation"]}
{"id": "paleo.009161", "title": "Aegicetus gehennae, a new late Eocene protocetid (Cetacea, Archaeoceti) from Wadi Al Hitan, Egypt, and the transition to tail-powered swimming in whales", "abstract": "Aegicetus gehennae is a new African protocetid whale based on a partial skull with much of an associated postcranial skeleton. The type specimen, Egyptian Geological Museum, Cairo [CGM] 60584, was found near the base of the early-Priabonian-age (earliest late Eocene) Gehannam Formation of the Wadi Al Hitan World Heritage Site in Egypt. The cranium is distinctive in having ventrally-deflected exoccipitals. The vertebral column is complete from cervical C1 through caudal Ca9, with a vertebral formula of 7:15:4:4:9+, representing, respectively, the number of cervical, thoracic, lumbar, sacral, and caudal vertebrae. CGM 60584 has two more rib-bearing thoracic vertebrae than other known protocetids, and two fewer lumbars. Sacral centra are unfused, and there is no defined auricular surface on the ilium. Thus there was no weight-bearing sacroiliac joint. The sternum is distinctive in being exceptionally broad and flat. The body weight of CGM 60584, a putative male, is estimated to have been about 890 kg in life. Long bones of the fore and hind limbs are shorter than expected for a protocetid of this size. Bones of the manus are similar in length and more robust compared to those of the pes. A log vertebral length profile for CGM 60584 parallels that of middle Eocene Maiacetus inuus through the anterior and middle thorax, but more posterior vertebrae are proportionally longer. Vertebral elongation, loss of a sacroiliac articulation, and hind limb reduction indicate that Aegicetus gehennae was more fully aquatic and less specialized as a foot-powered swimmer than earlier protocetids. It is doubtful that A. gehennae had a tail fluke, and the caudal flattening known for basilosaurids is shorter relative to vertebral column length than flattening associated with a fluke in any modern whale. Late protocetids and basilosaurids had relatively long skeletons, longer than those known earlier and later, and the middle-to-late Eocene transition from foot-powered to tail-powered swimming seemingly involved some form of mid-body-and-tail undulation.", "keyphrases": ["protocetid", "tail-powered swimming", "whale", "middle eocene", "aegicetus gehennae"]}
{"id": "paleo.001253", "title": "Competition in slow motion: the unusual case of benthic marine communities in the wake of the end\u2010Permian mass extinction", "abstract": "Changes of community structure in response to competition usually take place on timescales that are much too short to be visible in the geological record. Here we report the notable exception of a benthic marine community in the wake of the end\u2010Permian mass extinction, which is associated with the microbial limestone facies of the earliest Triassic of South China. The newly reported fauna is well preserved and extraordinarily rich (30 benthic macroinvertebrate species, including the new species Astartella? stefaniae (Bivalvia) and Eucochlis obliquecostata (Gastropoda)) and stems from an environmentally stable setting providing favourable conditions for benthic organisms. Whereas changes in the taxonomic composition are negligible over the observed time interval of 10\u2013100 ka, three ecological stages are identified, in which relative abundances of initially rare species continuously increased at the cost of previously dominant species. Concomitant with the changes of dominant species is an increase in faunal evenness and heterogeneity. In the absence of both environmental and taxonomic changes, we attribute this pattern to the long\u2010term effects of interspecific competition, which acted at an unusually slow pace because the number of competing species and potential immigrants was dramatically reduced by the end\u2010Permian mass extinction. We suggest that these non\u2010actualistic conditions led to decreased rates of niche differentiation and hence to the delayed rediversification of benthos that characterizes the aftermath of the greatest Phanerozoic mass extinction event. A hyperbolic diversification model is proposed, which accounts for the positive relationship between the intensity of interspecific competition and the rate of niche differentiation and resolves the conundrum of delayed rediversification at a time when niche space was largely vacated.", "keyphrases": ["marine community", "end\u2010permian mass extinction", "competition", "early triassic"]}
{"id": "10.1017/S1089332600001819", "title": "FAIR SAMPLING OF TAXONOMIC RICHNESS AND UNBIASED ESTIMATION OF ORIGINATION AND EXTINCTION RATES", "abstract": "Paleobiologists are reaching a consensus that biases in diversity curves, origination rates, and extinction rates need to be removed using statistical estimation methods. Diversity estimates are biased both by methods of counting and by variation in the amount of fossil data. Traditional counts are essentially tallies of age ranges. Because these counts are distorted by interrelated factors such as the Pull of the Recent and the Signor-Lipps effect, counts of taxa actually sampled within intervals should be used instead. Sampling intensity biases can be addressed with randomized subsampling of data records such as individual taxonomic occurrences or entire fossil collections. Fair subsampling would yield taxon counts that track changes in the species pool size, i.e., the diversity of all taxa that could ever be sampled. Most of the literature has overlooked this point, having instead focused on making sample sizes uniform through methods such as rarefaction. These methods flatten the data, undersampling when true diversity is high. A good solution to this problem involves the concept of frequency distribution coverage: a taxon's underlying frequency is said to be \u201ccovered\u201d when it is represented by at least one fossil in a data set. A fair subsample, but not a uniform one, can be created by drawing collections until estimated coverage reaches a fixed target (i.e., until a \u201cshareholder quorum\u201d is attained). Origination and extinction rates present other challenges. For many years they were thought of in terms of simple counts or ratios, but they are now treated as exponential decay coefficients of the kind featuring in simple birth-death models. Unfortunately, these instantaneous rates also suffer from counting method biases (e.g., the Pull of the Recent). Such biases can be removed by only examining taxa sampled twice consecutively, three times consecutively, or in the first and third of three intervals but not the second (i.e., two timers, three timers, and part timers). Two similar equations involving these counts can be used. Alternative methods of estimating diversity and turnover through extrapolation share some of the advantages of quorum subsampling and two-timer family equations, but it remains to be shown whether they produce precise and accurate estimates when applied to fossil data.", "keyphrases": ["sampling", "origination", "extinction rate", "count", "shareholder quorum"]}
{"id": "10.1006/jhev.1995.1046", "title": "Percussion marks, tooth marks, and experimental determinations of the timing of hominid and carnivore access to long bones at FLK Zinjanthropus, Olduvai Gorge, Tanzania", "abstract": "Competing hypotheses about the timing and nature of hominid and carnivore contributions to the formation of the Plio-Pleistocene bone assemblage from FLK Zinjanthropus are tested. The hypotheses advanced by Bunn (1986; Bunn and Kroll, 1986) and Leakey (197l), and by Binford (198l, 1986) are tested using the proportion of long bone specimens bearing hammerstone percussion marks and carnivore tooth marks. Unambiguous test implications based on surface mark frequencies are provided by results of well controlled experiments and naturalistic observations that model three alternative sequences of long bone processing and consumption by hominids and/or carnivores. Percussion mark and tooth mark frequencies, reported systematically for the first time on the assemblage from FLK Zinjanthropus, allow the rejection of the hypothesis that carnivores rather than hominids at FLK Zinjanthropus enjoyed first access to marrow in long bone cavities. This result contradicts Binford's characterization of Plio-Pleistocene hominids as marginal scavengers of carcasses heavily ravaged by bone-crunching carnivores. However, a high proportion of tooth-marked long bone midshaft fragments allows the rejection of the alternative hypothesis that carnivore access to long bones was exclusively or even primarily secondary to butchery and marrow extraction by hominids, as argued by Bunn (1986; Bunn and Kroll, 1986) and Leakey (1971). The results show that the sequence of carnivore and hominid access to long bones, and their respective carcass tissue yields, was more complex, as is consistent with a dominantly passive scavenging mode of carcass acquisition by hominids hypothesized earlier on the basis of skeletal part data and paleoecological considerations. \n \nConfidence in these deductions based on surface mark frequencies is increased by demonstrations of (i) a close comparability in agencies of bone fragmentation between the control samples and FLK Zinjanthropus; (ii) the representativeness of the control samples with respect to the process-pattern relationship between marrow/grease extraction and frequencies of surface marking; and (iii) the energetic and mechanical uniformities linking rates of bone surface marking to the timing of carnivore and hominid access to long bone nutrients.", "keyphrases": ["carnivore access", "long bone", "percussion mark"]}
{"id": "10.1029/1999GB900076", "title": "Redfield revisited: 2. What regulates the oxygen content of the atmosphere?", "abstract": "The continuous charcoal record, interpreted with the aid of the results of combustion experiments, indicates that the mixing ratio of atmospheric oxygen has varied remarkably little over the past 350 Myr. We develop a dynamic feedback model of the coupled P, N, C, and O2 cycles and use perturbation analysis and a case study of the past 40 Myr to test various feedback mechanisms that have been proposed to stabilize atmospheric oxygen. These mechanisms involve alterations in nutrient driven productivity and the subsequent burial flux of organic carbon, which provides the main source of atmospheric oxygen. Suppression of the burial of phosphorus sorbed to iron minerals under anoxic conditions in ocean bottom waters tends to increase the ocean nutrient inventory and provide negative feedback against declining oxygen [Holland, 1994]. However, denitrification is enhanced by anoxia, tending to reduce the nutrient inventory and amplify declining oxygen [Lenton and Watson, this issue]. If organic phosphorus removal from the ocean is also suppressed under anoxic conditions, this improves oxygen regulation [Van Cappellen and Ingall, 1994], as does direct enhancement of organic carbon burial due to reduced oxygen concentration in bottom waters [Betts and Holland, 1991]. However, all of the ocean\u2010based feedback mechanisms cease to operate under increases in oxygen that remove anoxia from the ocean. Fire frequency is extremely sensitive to increases in oxygen above 21% of the atmosphere, readily suppressing vegetation on the land surface. This should transfer phosphorus from the land to the ocean, causing less carbon to be buried per unit of phosphorus and providing a weak negative feedback on oxygen [Kump, 1988]. However, a new proposal that increases in oxygen suppress the biological amplification of rock weathering and hence the input of phosphorus to the Earth system provides the most effective oxygen regulation of all the mechanisms considered. A range of proxies suggests that the input of available phosphorus to the ocean may have been significantly reduced 40 Myr ago, suppressing new production and organic carbon burial in the model. With only ocean\u2010based feedback, the atmospheric oxygen reservoir is predicted to have shrunk from \u223c26% of the atmosphere 40 Myr ago. However, when land plant mediated negative feedback on phosphorus weathering is added, oxygen is regulated within 19\u201321% of the atmosphere throughout the past 40 Myr, in a manner more consistent with paleorecords.", "keyphrases": ["atmosphere", "organic carbon", "phosphoru", "anoxic condition", "available phosphorus"]}
{"id": "10.1017/S0016756820001028", "title": "Revisiting the tectonic evolution of the Triassic Palaeo-Tethys convergence zone in northern Thailand inferred from detrital zircon U\u2013Pb ages", "abstract": "Abstract Detrital zircon U\u2013Pb ages for sediments in and around the Palaeo-Tethyan convergence zone in northern Thailand provide constraints for tectonic interpretations of the Indochina Block, the Sibumasu Block, the Inthanon Zone accretionary complex and the Nan Back-arc Basin during the Triassic. In sedimentary rocks of the Indochina Block, almost all of the Palaeozoic and Triassic zircons were sourced from the collision zone between the Indochina and South China blocks, and an active continental margin in the western Indochina Block. Sediments of the Sibumasu Block were supplied by erosion of Archaean basement and from the Grenville and the Pan African orogenies, but show no record of Permian to Triassic igneous activity. Accretionary complex sediments have provenances of both the Sukhothai Arc and the Indochina and South China blocks, with detrital zircons of various ages being supplied from crustal uplift and erosion related to the Indosinian I orogeny. Sedimentary rocks of the Nan Back-arc Basin are widely distributed not only in the Nan\u2013Uttaradit but also in northern Sukhothai areas. The origin of the Pha Som Metamorphic Complex and associated formations can be traced to basin-filling sediments in the Nan Back-arc Basin. These detrital zircon U\u2013Pb ages have also allowed identification of the changing tectonic setting in the Palaeo-Tethys convergence zone from the \u2018erosion of Proterozoic continental basement\u2019 to \u2018Palaeozoic active continental margin in the western Indochina Block\u2019 and \u2018Palaeozoic, Permian to Triassic collision zone between the South China and Indochina blocks\u2019 through to \u2018Triassic active Sukhothai Arc\u2019.", "keyphrases": ["northern thailand", "zircon u\u2013pb age", "late permian faunas", "late carboniferous", "palaeotethyan"]}
{"id": "10.1111/nph.16882", "title": "Pollen analysis using multispectral imaging flow cytometry and deep learning.", "abstract": "Pollen identification and quantification are crucial but challenging tasks in addressing a variety of evolutionary and ecological questions (pollination, paleobotany), but also for other fields of research (e.g. allergology, honey analysis or forensics). Researchers are exploring alternative methods to automate these tasks but, for several reasons, manual microscopy is still the gold standard. In this study, we present a new method for pollen analysis using multi-spectral imaging flow cytometry in combination with deep learning. We demonstrate that our method allows fast measurement while delivering high accuracy pollen identification. A dataset of 426,876 images depicting pollen from 35 plant species was used to train a convolutional neural network classifier. We found the best-performing classifier to yield a species-averaged accuracy of 96 %. Even species that are difficult to differentiate using microscopy could be clearly separated. Our approach also allows a detailed determination of morphological pollen traits, such as size, symmetry or structure. Our phylogenetic analyses suggest phylogenetic conservatism in some of these traits. Given a comprehensive pollen reference database, we provide a powerful tool to be used in any pollen study with a need for rapid and accurate species identification, pollen grain quantification, and trait extraction of recent pollen.", "keyphrases": ["imaging flow cytometry", "deep learning", "pollen analysis"]}
{"id": "paleo.007714", "title": "Morphological variations in Cycloclypeus carpenteri: Multiple embryos and multiple equatorial layers", "abstract": "In this work, 17 specimens of Cycloclypeus carpenteri have been analysed by means of microCT scanning. It has been observed that many specimens possess multiple embryos, multiple nepionts and some tests show more than one equatorial layer. The diameter of each proloculus has been measured, and it seems that they are very variable even within the same specimen, therefore questioning the long known theory that schizonts have smaller proloculi than gamonts and also questioning the fact that proloculi in the same species should all have comparable size. Whenever the nepionts are positioned on different planes, thus creating an angle between them, this angle has a significant correlation to the angle connecting different equatorial layers. T-shaped connections are located at the junction between two equatorial layers; these junctions are made by a chamberlet, which possesses an unusually higher number of apertures, resembling the chamberlet structure of the genus Spiroclypeus.", "keyphrases": ["cycloclypeus carpenteri", "multiple embryo", "equatorial layer"]}
{"id": "paleo.008554", "title": "The homology and function of the lung plates in extant and fossil coelacanths", "abstract": "The presence of a pulmonary organ that is entirely covered by true bone tissue and fills most of the abdominal cavity is hitherto unique to fossil actinistians. Although small hard plates have been recently reported in the lung of the extant coelacanth Latimeria chalumnae, the homology between these hard structures in fossil and extant forms remained to be demonstrated. Here, we resolve this question by reporting the presence of a similar histological pattern\u2013true cellular bone with star-shaped osteocytes, and a globular mineralisation with radiating arrangement\u2013in the lung plates of two fossil coelacanths (Swenzia latimerae and Axelrodichthys araripensis) and the plates that surround the lung of the most extensively studied extant coelacanth species, L. chalumnae. The point-for-point structural similarity of the plates in extant and fossil coelacanths supports their probable homology and, consequently, that of the organ they surround. Thus, this evidence questions the previous interpretations of the fatty organ as a component of the pulmonary complex of Latimeria.", "keyphrases": ["homology", "lung plate", "fossil coelacanth"]}
{"id": "paleo.004642", "title": "A morphotype catalog and paleoenvironmental interpretations of early Miocene fossil leaves from the Hiwegi Formation", "abstract": "Early Miocene deposits on Rusinga Island (Lake Victoria, Kenya) contain an abundance of faunal and floral remains. Despite the attention that has historically been given to the early Miocene fauna from Rusinga Island, little attention has been given to the early Miocene fossil floras and to date no studies have described fossil leaf morphotypes from Rusinga Island. Here, we present a morphotype catalog of fossil leaves collected from the Grit Member of the Hiwegi Formation on Rusinga Island. We describe 14 morphotypes, comprised of 12 dicotyledonous angiosperms and two monocotyledonous angiosperms, as well as two distinct dicotyledonous angiosperm leaf fragments. Characteristics of the flora and sedimentological evidence, coupled with previous research, suggest that the local paleoenvironment was a riparian habitat within a patchwork of woodland and forested biomes in what was likely a warm climate. This work represents an important first step in understanding the early Miocene vegetation of Rusinga Island, and highlights both the need and potential for future research on these early Miocene floras.", "keyphrases": ["fossil leave", "hiwegi formation", "rusinga island", "kenya"]}
{"id": "paleo.003765", "title": "An exceptionally preserved Late Devonian actinopterygian provides a new model for primitive cranial anatomy in ray-finned fishes", "abstract": "Actinopterygians (ray-finned fishes) are the most diverse living osteichthyan (bony vertebrate) group, with a rich fossil record. However, details of their earliest history during the middle Palaeozoic (Devonian) \u2018Age of Fishes' remains sketchy. This stems from an uneven understanding of anatomy in early actinopterygians, with a few well-known species dominating perceptions of primitive conditions. Here we present an exceptionally preserved ray-finned fish from the Late Devonian (Middle Frasnian, ca 373 Ma) of Pas-de-Calais, northern France. This new genus is represented by a single, three-dimensionally preserved skull. CT scanning reveals the presence of an almost complete braincase along with near-fully articulated mandibular, hyoid and gill arches. The neurocranium differs from the coeval Mimipiscis in displaying a short aortic canal with a distinct posterior notch, long grooves for the lateral dorsal aortae, large vestibular fontanelles and a broad postorbital process. Identification of similar but previously unrecognized features in other Devonian actinopterygians suggests that aspects of braincase anatomy in Mimipiscis are apomorphic, questioning its ubiquity as stand-in for generalized actinopterygian conditions. However, the gill skeleton of the new form broadly corresponds to that of Mimipiscis, and adds to an emerging picture of primitive branchial architecture in crown gnathostomes. The new genus is recovered in a polytomy with Mimiidae and a subset of Devonian and stratigraphically younger actinopterygians, with no support found for a monophyletic grouping of Moythomasia with Mimiidae.", "keyphrases": ["actinopterygian", "anatomy", "ray-finned fish"]}
{"id": "paleo.007752", "title": "The integument of pelagic crocodylomorphs (Thalattosuchia: Metriorhynchidae)", "abstract": "Metriorhynchidae are the only archosaurs that show adaptations to a highly pelagic lifestyle. This morphology is paralleled by ichthyosaurs and plesiosaurs, which share a streamlined, largely scaleless skin surface. Although published metriorhynchid material indicates a similar condition, no detailed description of their integument has been carried out. New data from several specimens representing at least three genera are shown here, revealing a uniform skin type lacking any traces of scales or scutes and instead showing folded and transverse fibers. A hypocercal tail fluke comparable to that of ichthyosaurs is present in metrorhynchids. Surface anomalies on metriorhynchid skin are interpreted as potential epizootic scars, similar to those from barnacles, or bite marks. A broad comparison implies deep homologies with plesiosaur and ichthyosaur skin. We also describe skin details of early (teleosauroid) thalattosuchians for the first time. Unlike Metriorhynchidae, their integument is demonstrated to be very similar to that of extant crocodylians, which can be partially explained by their inferred onshore behavior. There is generally a high threshold for extensive skin modifications in aquatic reptiles. Frederik Spindler. Dinosaurier Museum Altm\u00fchltal, Dinopark 1, 85095 Denkendorf, Germany. mail@frederik-spindler.de Ren\u00e9 Lauer. Lauer Foundation for Paleontology, Science and Education, Wheaton, Illinois, USA. rene@lauerfoundationpse.org Helmut Tischlinger. Tannenweg 16, 85134 Stammham, Germany and Jura-Museum Eichst\u00e4tt, Willibaldsburg, 85072 Eichst\u00e4tt, Germany. htischlinger@online.de Matthias M\u00e4user. Staatliche Naturwissenschaftliche Sammlungen Bayerns, Naturkunde-Museum Bamberg, Fleischstr. 2, 96047 Bamberg, Germany. maeuser@snsb.de", "keyphrases": ["integument", "metriorhynchidae", "archosaur", "pelagic lifestyle"]}
{"id": "10.1029/2007pa001532", "title": "Sea surface temperature and salinity variability at Bermuda during the end of the Little Ice Age", "abstract": "[1]\u00a0We use geochemical and isotope measurements on a 225-year old brain coral (Diploria labyrinthiformis) from the south shore of Bermuda (64\u00b0W, 32\u00b0N) to construct a record of decadal-to-centennial-scale climate variability. The coral was collected alive, and annual density bands visible in X radiographs delineate cold and warm seasons allowing for precise dating. Coral skeletons incorporate strontium (Sr) and calcium (Ca) in relative proportions inversely to the sea surface temperature (SST) in which the skeleton is secreted. Previous studies on this and other coral colonies from this region document the ability to reconstruct mean annual and wintertime SST using Sr/Ca measurements (Goodkin et al., 2007, 2005). The coral-based records of SST for the past 2 centuries show abrupt shifts at both decadal and centennial timescales and suggest that SST at the end of the Little Ice Age (between 1840 and 1860) was 1.5\u00b0 \u00b1 0.4\u00b0C colder than today (1990s). Coral-reconstructed SST has a greater magnitude change than does a gridded instrumental SST record from this region. This may result from several physical processes including high rates of mesoscale eddy propagation in this region. Oxygen isotope values (\u03b418O) of the coral skeleton reflect changes in both temperature and the \u03b418O of seawater (\u03b4Ow), where \u03b4Ow is proportional to sea surface salinity (SSS). We show in this study that mean annual and wintertime \u03b418O of the carbonate (\u03b4Oc) are correlated to both SST and SSS, but a robust, quantitative measure of SSS is not found with present calibration data. In combination, however, the Sr/Ca and \u03b4Oc qualitatively reconstruct lower salinities at the end of the Little Ice Age relative to modern day. Temperature changes agree with other records from the Bermuda region. Radiative and atmospheric forcing may explain some of the SST variability, but the scales of implied changes in SST and SSS indicate large-scale ocean circulation impacts as well.", "keyphrases": ["bermuda", "little ice age", "sea surface temperature"]}
{"id": "10.1111/j.1469-7580.2007.00786.x", "title": "A new prey\u2010detection mechanism for kiwi (Apteryx spp.) suggests convergent evolution between paleognathous and neognathous birds", "abstract": "Kiwi (Apterygidae: Apteryx spp.) are traditionally assumed to detect their soil\u2010dwelling invertebrate prey using their sense of smell. The unique position of the nares at the tip of the bill and the enlarged olfactory centres in the brain support this assumption. However, studies designed to show the importance of olfaction in prey\u2010detection by Apteryx have provided equivocal results. Another family of probing birds, the Scolopacidae, detect their buried prey using specialised vibration and pressure\u2010sensitive mechanoreceptors embedded in pits in the bill\u2010tip. We found that aspects of the foraging patterns of Apteryx mantelli are like those of scolopacid shorebirds, suggesting that Apteryx may be using a similar prey\u2010detection mechanism. We examined specimens of all five Apteryx species and conducted a morphological and histological examination of the bill of A. mantelli. We discovered that Apteryx possess an arrangement of mechanoreceptors within pits similar to that in Scolopacidae species and may therefore be able to localise prey using a similar vibrotactile sense. We suggest that this sense may function in conjunction with, or be dominant over, olfaction during prey\u2010detection. The Apterygidae and the Scolopacidae are members of the two different super\u2010orders of birds: the Paleognathae and the Neognathae, respectively. Therefore we cite the similar bill\u2010tip anatomy of these two families as an example of convergent evolution across a deep taxonomic divide.", "keyphrases": ["prey\u2010detection mechanism", "kiwi", "convergent evolution", "apterygidae", "scolopacidae"]}
{"id": "10.2458/56.16270", "title": "Redating Shuidonggou Locality 1 and Implications for the Initial Upper Paleolithic in East Asia", "abstract": "A review of recently published temporal data from Shuidonggou Locality 1 indicates that a 40\u201343 cal ka date for the inception of Initial Upper Paleolithic (IUP) blade-oriented technologies in East Asia is warranted. Comparison of the dates from Shuidonggou to other Asian IUP dates in Korea, Siberia, and Mongolia supports this assertion, indicating that the initial appearance of the IUP in East Asia generally corresponds in time to the fluorescence of the IUP in eastern Europe and western Asia. This conclusion preliminarily suggests that either a version of the IUP originated independently in East Asia just prior to 40 cal ka, or more likely, that an early, initial diffusion of the IUP into East Asia occurred \u223c41 cal ka, a hypothesis consistent with current estimates for the evolution or arrival of modern humans in the region.", "keyphrases": ["shuidonggou locality", "initial upper paleolithic", "east asia"]}
{"id": "10.1002/ar.24567", "title": "Paleoneurology of Baurusuchus (Crocodyliformes: Baurusuchidae), ontogenetic variation, brain size, and sensorial implications", "abstract": "Knowledge on crocodyliform paleoneurology has significantly improved with development of computed tomography. However, studies so far have been able to reconstruct brain endocasts based only on single specimens for each taxon. Here for the first time, we reconstructed brain endocasts for multiple fossil specimens of the same crocodyliform taxon (Baurusuchus), consisting of complete skulls of two medium sized specimens, one large adult, and a late juvenile. In addition, we were able to reconstruct the inner ear anatomy of a fragmentary skull using microtomography. We present estimates of brain size using simple models, based on modern Crocodylia, able to adapt brain to endocranial cavity ratios to expected ontogenetic variation instead of using fixed ratios. We also analyzed relative brain sizes, olfactory ratios, facial sensation, alert head posture, best hearing frequencies, and hearing range. The calculated endocranial volumes showed that they can be greatly altered by taphonomic processes, altering both total and partial endocranial volumes. Reconstructed endocasts are compatible with different degrees of occupation along the endocranial cavity and some of their characteristics might be useful as phylogenetic characters. The relative brain size of Baurusuchus seems to be small in comparison to modern crocodilians. Sensorial abilities were somewhat similar to modern crocodilians and hearing ranges and best mean frequencies remarkably similar to modern taxa, whereas olfactory ratio values are a little higher. Differing from its modern relatives, Baurusuchus hypothesized alert head posture is compatible with a terrestrial habit.", "keyphrases": ["baurusuchus", "ontogenetic variation", "brain size"]}
{"id": "10.1130/GES01048.1", "title": "Stratigraphic trends in detrital zircon geochronology of upper Neoproterozoic and Cambrian strata, Osgood Mountains, Nevada, and elsewhere in the Cordilleran miogeocline: Evidence for early Cambrian uplift of the Transcontinental Arch", "abstract": "U-Pb detrital zircon geochronology provides insight into the provenance of the upper Neoproterozoic\u2013lower Cambrian Osgood Mountain Quartzite and the upper Cambrian\u2013lower Ordovician Preble Formation in the Osgood Mountains of northern Nevada (USA). We analyzed 535 detrital zircon grains from six samples of quartz arenite by laser ablation\u2013multicollector\u2013inductively coupled plasma\u2013mass spectrometry. The detrital zircon age data of these Neoproterozoic\u2013lower Paleozoic passive margin units record a provenance change within the Osgood Mountain Quartzite. Comparison of these data with the work of others reveals that this change in provenance occurred in correlative strata throughout an east-west transect of the Great Basin. From latest Neoproterozoic through earliest Cambrian time, most grains were shed from the 1.0\u20131.2 Ga Grenville orogen. After that time, drainage patterns changed and most grains were derived from the 1.6\u20131.8 Ga Yavapai and Mazatzal provinces; very few grains from the Grenville orogen were found in the younger strata. We suggest that this shift records the uplift, in early Cambrian time, of the Transcontinental Arch. Our data also support our interpretation that the Osgood Mountain Quartzite and the Preble Formation are correlative to other contemporaneous passive margin strata in western Laurentia.", "keyphrases": ["detrital zircon geochronology", "neoproterozoic", "uplift"]}
{"id": "paleo.008908", "title": "Brachiopods: origin and early history", "abstract": "Despite many major advances in recent years, three key challenges remain in bringing clarity to the early history of the phylum: (1) identifying the origin, morphology and life modes of the first brachiopods; (2) understanding the relationships of the major groups to each other and higher sister taxa; and (3) unravelling the roles of the Cambrian and Ordovician radiations that set the agenda for much of subsequent brachiopod evolution. Since some 95% of all brachiopod taxa are extinct, the fossil record is the primary source of data to frame and test models for the evolution of the phylum. The acquisition of new, and the redescription of existing faunas, in precise spatial and temporal frameworks, using new and well\u2010established analytical and investigative techniques, are as important as ever.", "keyphrases": ["early history", "phylum", "brachiopod"]}
{"id": "10.1029/2012GL054118", "title": "Direct ventilation of the North Pacific did not reach the deep ocean during the last deglaciation", "abstract": "Despite its tremendous size, the deep North Pacific has received relatively little attention by paleoceanographers. It was recently suggested that the deep North Pacific was directly ventilated by dense waters formed in the subarctic Pacific during Heinrich Stadial 1 (HS1) of the early deglaciation. Here we present new redox\u2010sensitive trace metal data from a sediment core at 2393\u2009m in the subarctic Pacific, in comparison with previously published data from elsewhere in the region. The combined picture shows no sign of ventilation during the early deglaciation in any available core from water depths of 2393\u2009m and deeper, while the deepest core to display clear signs of enhanced ventilation during HS1 was raised from 1366\u2009m water depth. Thus, it appears likely that, although the North Pacific was well ventilated to intermediate depths during HS1, the deep ocean did not receive a significant input of dense waters from a local source, but remained isolated from the surface waters above.", "keyphrases": ["ventilation", "north pacific", "deep ocean"]}
{"id": "10.1017/jpa.2019.85", "title": "Nature and significance of intraspecific variation in the early Cambrian oryctocephalid trilobite Oryctocephalites palmeri Sundberg and McCollum, 1997", "abstract": "Abstract. Oryctocephalid trilobites are seldom abundant and often tectonically deformed, creating problems for robust species delimitation and compromising their utility in biostratigraphic and evolutionary studies. By studying more than 140 specimens recovered from the upper portion of the Combined Metals Member (Pioche Formation, Nevada; Cambrian Stage 4, Series 2), we exploit a rare opportunity to explore how morphological variation among oryctocephalid specimens is partitioned into intraspecific variation versus interspecific disparity. Qualitative and quantitative analyses reveal that two species are represented: Oryctocephalites palmeri Sundberg and McCollum, 1997 and Oryctocephalites sp. A, the latter known from a single cranidium stratigraphically below all occurrences of the former. In contrast to the conclusions of a previous study, there is no evidence of cranidial dimorphism in O. palmeri. However, that species exhibits considerable variation in cranidial shape and pygidial spine arrangement and number. Cranidial shape variation within O. palmeri is approximately one-half of the among-species disparity within the genus. Comparison of cranidial shape between noncompacted and compacted samples reveals that compaction causes significant change in mean shape and an increase in shape variation; such changes are interpretable in terms of observed fracture patterns. Nontaphonomic variation is partitioned into ontogenetic and nonallometric components. Those components share similar structure with each other and with interspecific disparity, suggesting that ontogenetic shape change might be an important source of variation available for selection. This highlights the importance of ontogenetic and taphonomic sources of variation with respect to species delimitation, morphospace occupation, and investigation of evolutionary patterns and processes.", "keyphrases": ["intraspecific variation", "oryctocephalite", "mccollum"]}
{"id": "paleo.008339", "title": "Australia's oldest Anseriform fossil: a quadrate from the Early Eocene Tingamarra Fauna", "abstract": "Abstract:\u2002 A partial quadrate (essentially the otic part) from the nonmarine, earliest Eocene (54.6\u2003Ma) Tingamarra Local Fauna in Queensland, Australia, has been identified as the oldest Australian anseriform fossil. The Tingamarra quadrate shows a combination of plesiomorphic anseriform characters with a unique synapomorphic character complex of the Anhimidae (screamers), which today are endemic to South America. In concert with the basal position of the Anhimidae among the crown\u2010group anseriforms, this set of characters suggests a stem group of the Anhimidae, raising a possibility of the Transantarctic migration of stem anhimids to South America. The quadrate morphology supports palaeognathous rather than recently claimed anhimid relationships of the Dromornithidae and identifies Sylviornis as an anseriform rather than a galliform.", "keyphrases": ["anseriform fossil", "quadrate", "australia"]}
{"id": "10.1130/G25213A.1", "title": "Diachronous dawn of Africa's Middle Stone Age: New 40Ar/39Ar ages from the Ethiopian Rift", "abstract": "The Middle Stone Age (MSA) of Africa, like the Middle Paleolithic of Europe, is thought to represent a time period wherein toolmakers acquired significant increases in cognitive abilities and physical dexterity. Existing data fail to resolve whether the MSA emerged gradually, abruptly, or discontinuously, and whether this industry reflects the activity of Homo sapiens. Here we present new 40 Ar/ 39 Ar geochronological data revealing that advanced MSA archaeology at two sites in the main Ethiopian Rift is older than 276 ka, much older than technologically comparable MSA archaeology from elsewhere. An age of 183 ka for a unit farther upsection, along with the technological stasis observed throughout the section, indicates that similar technology was used here for ~93 ka. These results suggest that MSA technology evolved asynchronously in different places, and challenge the notion of a distinct time line for either the appearance of the MSA or the disappearance of the earlier Acheulean. These and other recent results indicate that the oldest known MSA consistently predates fossil evidence for the earliest Homo sapiens.", "keyphrases": ["africa", "middle stone age", "ethiopian rift"]}
{"id": "paleo.002594", "title": "The northernmost Eurasian Miocene beavers: Euroxenomys (Castoridae, Mammalia) from Olkhon Island, Lake Baikal (Eastern Siberia)", "abstract": "The castorid dental material described in this paper derives from Miocene, fossiliferous deposits of the Baikal rift valley, exposed at Tagay Bay on Olkhon Island in the Lake Baikal, in eastern Siberia. It consists of maxillary fragments and isolated upper and lower teeth of the small trogontheriine beaver Euroxenomys minutus (von Meyer, 1838) . It is the first record of the species in Asia and at the same time the northernmost occurrence of Eurasian Miocene beavers. The magnetostratigraphic correlation of the Tagay -1 section, indicates a late Burdigalian, Early/early Middle Miocene age of ~16.5 to ~16.3 Ma that corresponds to the Mammalian Neogene zone MN4/5. The presence of E. minutus in Tagay is an indicator for an Orleanian European-Siberian bioprovince during the Mid-Miocene Climate Optimum, and for a continuous belt of humid, warm-temperate to subtropical forests, stretching from Europe to Siberia, and probably further to East and South-Eastern Asia. In Eurasia, beaver remains are an indicator of permanent water bodies, which is in agreement with the palaeoenvironment of the Tagay locality.", "keyphrases": ["eurasian miocene beaver", "castoridae", "olkhon island", "fossil collection", "small mammal tooth"]}
{"id": "paleo.005617", "title": "Historical data as a baseline for conservation: reconstructing long-term faunal extinction dynamics in Late Imperial\u2013modern China", "abstract": "Extinction events typically represent extended processes of decline that cannot be reconstructed using short-term studies. Long-term archives are necessary to determine past baselines and the extent of human-caused biodiversity change, but the capacity of historical datasets to provide predictive power for conservation must be assessed within a robust analytical framework. Local Chinese gazetteers represent a more than 400-year country-level dataset containing abundant information on past environmental conditions and include extensive records of gibbons, which have a restricted present-day distribution but formerly occurred across much of China. Gibbons show pre-twentieth century range contraction, with significant fragmentation by the mid-eighteenth century and population loss escalating in the late nineteenth century. Isolated gibbon populations persisted for about 40 years before local extinction. Populations persisted for longer at higher elevations, and disappeared earlier from northern and eastern regions, with the biogeography of population loss consistent with the contagion model of range collapse in response to human demographic expansion spreading directionally across China. The long-term Chinese historical record can track extinction events and human interactions with the environment across much longer timescales than are usually addressed in ecology, contributing novel baselines for conservation and an increased understanding of extinction dynamics and species vulnerability or resilience to human pressures.", "keyphrases": ["conservation", "extinction dynamic", "analytical framework", "environmental condition"]}
{"id": "paleo.012491", "title": "The Antiquity and Evolutionary History of Social Behavior in Bees", "abstract": "A long-standing controversy in bee social evolution concerns whether highly eusocial behavior has evolved once or twice within the corbiculate Apidae. Corbiculate bees include the highly eusocial honey bees and stingless bees, the primitively eusocial bumble bees, and the predominantly solitary or communal orchid bees. Here we use a model-based approach to reconstruct the evolutionary history of eusociality and date the antiquity of eusocial behavior in apid bees, using a recent molecular phylogeny of the Apidae. We conclude that eusociality evolved once in the common ancestor of the corbiculate Apidae, advanced eusociality evolved independently in the honey and stingless bees, and that eusociality was lost in the orchid bees. Fossil-calibrated divergence time estimates reveal that eusociality first evolved at least 87 Mya (78 to 95 Mya) in the corbiculates, much earlier than in other groups of bees with less complex social behavior. These results provide a robust new evolutionary framework for studies of the organization and genetic basis of social behavior in honey bees and their relatives.", "keyphrases": ["evolutionary history", "social behavior", "bee"]}
{"id": "paleo.003857", "title": "Olson's Extinction and the latitudinal biodiversity gradient of tetrapods in the Permian", "abstract": "The terrestrial vertebrate fauna underwent a substantial change in composition between the lower and middle Permian. The lower Permian fauna was characterized by diverse and abundant amphibians and pelycosaurian-grade synapsids. During the middle Permian, a therapsid-dominated fauna, containing a diverse array of parareptiles and a considerably reduced richness of amphibians, replaced this. However, it is debated whether the transition is a genuine event, accompanied by a mass extinction, or whether it is merely an artefact of the shift in sampling from the palaeoequatorial latitudes to the palaeotemperate latitudes. Here we use an up-to-date biostratigraphy and incorporate recent discoveries to thoroughly review the Permian tetrapod fossil record. We suggest that the faunal transition represents a genuine event; the lower Permian temperate faunas are more similar to lower Permian equatorial faunas than middle Permian temperate faunas. The transition was not consistent across latitudes; the turnover occurred more rapidly in Russia, but was delayed in North America. The argument that the mass extinction is an artefact of a latitudinal biodiversity gradient and a shift in sampling localities is rejected: sampling correction demonstrates an inverse latitudinal biodiversity gradient was prevalent during the Permian, with peak diversity in the temperate latitudes.", "keyphrases": ["latitudinal biodiversity gradient", "tetrapod", "permian", "latitude"]}
{"id": "10.11646/palaeoentomology.4.4.14", "title": "The earliest record of fossil solid-wood-borer larvae\u2014immature beetles in 99 million-year-old Myanmar amber", "abstract": "Interactions between animals and plants represent an important driver of evolution. Especially the group Insecta has an enormous impact on plants, e.g., by consuming them. Among beetles, the larvae of different groups (Buprestidae, Cerambycidae, partly Eucnemidae) bore into wood and are therefore called wood-borer larvae or borers. While adults of these beetle groups are well known in the fossil record, there are barely any fossils of the corresponding larvae. We report here four new wood-borer larvae from Cretaceous Kachin amber (Myanmar, ca. 99 Ma). To compare these fossils with extant wood-borer larvae, we reconstructed the body outline and performed shape analysis via elliptic Fourier transformation and a subsequent principal component analysis. Two of the new larvae plot closely together and clearly in the same area as modern representatives of Buprestidae. As they furthermore lack legs, they are interpreted as representatives of Buprestidae. The other two new larvae possess legs and plot far apart from each other. They are more difficult to interpret; they may represent larvae of early offshoots of either Cerambycidae or Buprestidae, which still retain longer legs. These findings represent the earliest fossil record of larvae of Buprestidae and possibly of Cerambycidae known to date.", "keyphrases": ["million-year-old myanmar amber", "cerambycidae", "borer", "solid-wood borer"]}
{"id": "paleo.005271", "title": "Spatial distribution of oncocerid cephalopods on a Middle Devonian bedding plane suggests semelparous life cycle", "abstract": "Reproductive strategies of extinct organisms can only be recognised indirectly and hence, they are exceedingly rarely reported and tend to be speculative. Here, we present a mass-occurrence with common preservation of pairs of late Givetian (Middle Devonian) oncocerid cephalopods from Hamar Laghdad in the Tafilalt (eastern Anti-Atlas, Morocco). We analysed their spatial occurrences with spatial point pattern analysis techniques and Monte carlo simulations; our results shows that the pairwise clustering is significant, while ammonoids on the same bedding plane reveal a more random distribution. it is possible that processes such as catastrophic mass mortality or post-mortem transport could have produced the pattern. However, we suggest that it is more likely that the oncocerids were semelparous and died shortly after mating. These findings shed new light on the variation and evolution of reproductive strategies in fossil cephalopods and emphasise that they cannot be based on comparisons with extant taxa without question.\nAmong the two major clades of living cephalopods, the Coleoidea and Nautiloidea, there is a broad range of reproductive strategies. Coleoids were long considered to be invariably semelparous (reproducing only once), while Nautilus is iteroparous (giving rise to offspring multiple times) 1 . However, in recent years, squid, octopus and cuttlefish were shown to exhibit a wide range of reproductive strategies and life cycles 2 . Nevertheless, although its reproductive biology is still poorly known, Nautilus is unique among living cephalopods in its polycyclic spawning and long life span, in contrast to the monocyclic spawning (which can occur in separate batches or during an extended time period) of the relatively short-lived coleoids 1,2 .\nStudies of the reproduction strategies of the mostly externally shelled fossil cephalopods are very rare, largely because the scarcity of soft part preservation strongly limits the possibilities of these investigations. Yet, cephalopods such as ammonoids, bactritids and orthocerids possess small protoconchs and thus eggs and hatchlings; accordingly, they are often considered to be close to coleoids in their reproductive strategy, while cephalopods with large embryonic shells are generally considered to be closer to the living Nautilus 3-6 . In addition, nautiloids are usually thought to be K-strategists (type I survivorship), while coleoids, ammonoids, bactritids and partly orthocerids are seen as r-strategists (type III survivorship 3,7 ). However, since both K-and r-strategies occur among recent coleoids combined with a semelparous life cycle 2 , these assumptions may be too simple. In addition, the paradigm of K-and r-strategy 8 has been abandoned in the field of life-history evolution for some time 9 .\nPrevious studies have focused on life history traits that can be assessed with some reliability. For example, the mode of life of hatchlings can be inferred from the size of the embryonic shell and facies distribution, while the relative size of the hatchling to the adult can be informative about fecundity 5, 10 . Iteroparity or semelparity is more difficult to identify in fossil cephalopods as direct evidence is lacking. In some cases, it has been inferred from combinations of the aforementioned life history traits 11, 12 ; however, these may not always be good predictors. Apparent mass spawning events in the Late Devonian ammonoid Prolobites were seen as support for their similarity to coleoids in terms of reproduction 13 . Further mass occurrences of several ammonoid species in the Middle Carboniferous of Arkansas were similarly interpreted as support for semelparity 14 . In another case, ovoviviparity,", "keyphrases": ["cephalopod", "middle devonian", "bedding plane", "hatchling", "fecundity"]}
{"id": "10.1080/00379271.2004.10697402", "title": "A \u201cstick insect-like\u201d from the Triassic of the Vosges (France) (\u201cpre-Tertiary Phasmatodea\u201d)", "abstract": "R\u00e9sum\u00e9 Palaeochresmoda grauvogeli, new genus and species of \u201cstick insect-like\u201d is described from the Lower-Middle Triassic of France. It is the oldest known Prochresmodidae and probably \u201cpre-Tertiary Phasmatodea\u201d. The importance of phylogenetic analyses is emphasized for the estimations of the insect palaeobiodiversity and the crises that could have affected it.", "keyphrases": ["stick insect-like", "triassic", "phasmatodea"]}
{"id": "10.7717/peerj.1130", "title": "Interpreting pathologies in extant and extinct archosaurs using micro-CT", "abstract": "Palaeopathology offers unique insight to the healing strategies of extinct organisms, permitting questions concerning bone physiology to be answered in greater depth. Unfortunately, most palaeopathological studies are confined to external morphological interpretations due to the destructive nature of traditional methods of study. This limits the degree of reliable diagnosis and interpretation possible. X-ray MicroTomography (micro-CT, XMT) provides a non-destructive means of analysing the internal three-dimensional structure of pathologies in both extant and extinct individuals, at higher resolutions than possible with medical scanners. In this study, we present external and internal descriptions of pathologies in extant and extinct archosaurs using XMT. This work demonstrates that the combination of external/internal diagnosis that X-ray microtomography facilitates is crucial when differentiating between pathological conditions. Furthermore, we show that the use of comparative species, both through direct analysis and from the literature, provides key information for diagnosing between vertebrate groups in the typical pathological conditions and physiological processes. Micro-CT imaging, combined with comparative observations of extant species, provides more detailed and reliable interpretation of palaeopathologies. Micro-CT is an increasingly accessible tool, which will provide key insights for correctly interpreting vertebrate pathologies in the future.", "keyphrases": ["pathology", "extinct archosaur", "micro-ct"]}
{"id": "paleo.005821", "title": "An intermediate crocodylian linking two extant gharials from the Bronze Age of China and its human-induced extinction", "abstract": "A solid phylogenetic framework is the basis of biological studies, yet higher level relationships are still unresolved in some major vertebrate lineages. One such group is Crocodylia, where the branching pattern of three major families (Alligatoridae, Crocodylidae and Gavialidae) has been disputed over decades due to the uncertain relationship of two slender-snouted lineages, gavialines and tomistomines. Here, we report a bizarre crocodylian from the Bronze Age of China, which shows a mosaic of gavialine and tomistomine features across the skeleton, rendering support to their sister taxon relationship as molecular works have consistently postulated. Gavialine characters of the new Chinese crocodylian include a novel configuration of the pterygoid bulla, a vocal structure known in mature male Indian gharials. Extinct gavialines have repeatedly evolved potentially male-only acoustic apparatus of various shapes, illuminating the deep history of sexual selection on acoustic signalling in a slender-snouted group of crocodylians. Lastly, a cutmark analysis combined with accelerator mass spectrometry (AMS) radiocarbon dating of bone remains demonstrated that two individuals from Shang and Zhou dynasties in Guangdong, China, suffered head injuries and decapitation. Archaeological evidence together with historical accounts suggests the human-induced extinction of this unique crocodylian only a few hundred years ago.", "keyphrases": ["crocodylian", "bronze age", "human-induced extinction"]}
{"id": "paleo.008970", "title": "Chamber volume development, metabolic rates, and selective extinction in cephalopods", "abstract": "Reconstructing the physiology of extinct organisms is key to understanding mechanisms of selective extinction during biotic crises. Soft tissues of extinct organisms are rarely preserved and, therefore, a proxy for physiological aspects is needed. Here, we examine whether cephalopod conchs yield information about their physiology by assessing how the formation of chambers respond to external stimuli such as environmental changes. We measured chamber volume through ontogeny to detect differences in the pattern of chamber volume development in nautilids, coleoids, and ammonoids. Results reveal that the differences between ontogenetic trajectories of these cephalopods involve the presence or absence of abrupt decreases of chamber volume. Accepting the link between metabolic rate and growth, we assume that this difference is rooted in metabolic rates that differ between cephalopod clades. High metabolic rates combined with small hatching size in ammonoids as opposed to lower metabolic rates and much larger hatchlings in most nautilids may explain the selective extinction of ammonoids as a consequence of low food availability at the end of the Cretaceous.", "keyphrases": ["metabolic rate", "cephalopod", "ammonoid", "food availability", "chamber volume development"]}
{"id": "10.1017/jpa.2017.29", "title": "Limulitella tejraensis, a new species of limulid (Chelicerata, Xiphosura) from the Middle Triassic of southern Tunisia (Saharan Platform)", "abstract": "Abstract. \n Numerous well-preserved remains of a new limulid species from the Anisian-lower Ladinian (Middle Triassic) of the Tejra section of southern Tunisia are described. Comparisons are made with limulids from the Triassic deposits of Europe and Australia. The new specimens are congeneric with the type species of Limulitella, but show some morphological differences. Here we describe Limulitella tejraensis new species, a small limulid with semicircular prosoma, small and triangular opisthosoma, well-defined axial ridge, and pleurae along both ridges of the opisthosoma. The Tunisian Limulitella fossils are associated with conchostracans, bivalves, gastropods, and microconchids. Sedimentological and paleontological data from the Tejra section suggest freshwater to brackishwater conditions during the formation of the fossil-bearing interval and the influence of marine transgression into a playa-like environment. Supposed adaptation to the stressful environment sheds new light on the origin and survival of the extant limulines. This is the first report of limulid body fossils from the Triassic of North Africa and the first documentation of Limulitella in the Middle Triassic of northern Gondwanaland.", "keyphrases": ["middle triassic", "southern tunisia", "limulitella tejraensis"]}
{"id": "paleo.003459", "title": "A refined modelling approach to assess the influence of sampling on palaeobiodiversity curves: new support for declining Cretaceous dinosaur richness", "abstract": "Modelling has been underdeveloped with respect to constructing palaeobiodiversity curves, but it offers an additional tool for removing sampling from their estimation. Here, an alternative to subsampling approaches, which often require large sample sizes, is explored by the extension and refinement of a pre-existing modelling technique that uses a geological proxy for sampling. Application of the model to the three main clades of dinosaurs suggests that much of their diversity fluctuations cannot be explained by sampling alone. Furthermore, there is new support for a long-term decline in their diversity leading up to the Cretaceous\u2013Paleogene (K\u2013Pg) extinction event. At present, use of this method with data that includes either Lagerst\u00e4tten or \u2018Pull of the Recent\u2019 biases is inappropriate, although partial solutions are offered.", "keyphrases": ["modelling approach", "palaeobiodiversity curve", "new support"]}
{"id": "10.1073/pnas.1509747112", "title": "Early human use of anadromous salmon in North America at 11,500 y ago", "abstract": "Significance Fish bones from the 11,500-y-old Upward Sun River site in interior Alaska represent the oldest evidence for salmon fishing in North America. We used ancient DNA analysis to identify the fish specimens as chum salmon (Oncorhynchus keta), and stable isotope analysis to confirm that the salmon were anadromous (sea-run). The exploitation of salmon at this early date is noteworthy because Paleoindians are traditionally portrayed as big-game hunting specialists. Furthermore, the presence of salmon at Upward Sun River over 1,400 km upriver from the coast shows that spawning runs had been established by the end of the last Ice Age. The early availability and use of anadromous salmon has important implications for understanding Paleoindian economies and expansion into North America. Salmon represented a critical resource for prehistoric foragers along the North Pacific Rim, and continue to be economically and culturally important; however, the origins of salmon exploitation remain unresolved. Here we report 11,500-y-old salmon associated with a cooking hearth and human burials from the Upward Sun River Site, near the modern extreme edge of salmon habitat in central Alaska. This represents the earliest known human use of salmon in North America. Ancient DNA analyses establish the species as Oncorhynchus keta (chum salmon), and stable isotope analyses indicate anadromy, suggesting that salmon runs were established by at least the terminal Pleistocene. The early use of this resource has important implications for Paleoindian land use, economy, and expansions into northwest North America.", "keyphrases": ["human use", "anadromous salmon", "north america"]}
{"id": "paleo.002463", "title": "First megafossil record of Neolepisorus (Polypodiaceae) from the late Miocene of Yunnan, Southwest China", "abstract": "The first megafossil record of the genus Neolepisorus Ching from the late Miocene of Yunnan Province, SW China, is reported. Neolepisorus chingii sp. nov. is represented by a simple fertile frond with one line exindusiate, elliptic-fusiform sori along the lower part of the midrib, and a basal contractive sterile frond with a sinuolate margin. The venation is characterized by a strong midrib, prominent zigzagging lateral veins, and reticulate higher order veins with free-ending veinlets (simple or forked once). The combination of these characters confirms the genus Neolepisorus (Polypodiaceae), now distributed in subtropical Southeast Asia, except for one species, which inhabits Madagascar of tropical Africa. It has a distribution center south of the Yangtze River in China. So far, no megafossil assigned to Neolepisorus has been reported, and the occurrence of Neolepisorus chingii in SW China associated with other types of fern occurrence adds increased evidence of fern radiation during the Neogene in Yunnan Province in response to the uplift of the Tibetan Plateau.", "keyphrases": ["polypodiaceae", "late miocene", "first megafossil record"]}
{"id": "paleo.010019", "title": "Fossil scales illuminate the early evolution of lepidopterans and structural colors", "abstract": "Mesozoic lepidopteran wing scales shed light on the early evolution of moths and structural colors. Lepidopteran scales exhibit remarkably complex ultrastructures, many of which produce structural colors that are the basis for diverse communication strategies. Little is known, however, about the early evolution of lepidopteran scales and their photonic structures. We report scale architectures from Jurassic Lepidoptera from the United Kingdom, Germany, Kazakhstan, and China and from Tarachoptera (a stem group of Amphiesmenoptera) from mid-Cretaceous Burmese amber. The Jurassic lepidopterans exhibit a type 1 bilayer scale vestiture: an upper layer of large fused cover scales and a lower layer of small fused ground scales. This scale arrangement, plus preserved herringbone ornamentation on the cover scale surface, is almost identical to those of some extant Micropterigidae. Critically, the fossil scale ultrastructures have periodicities measuring from 140 to 2000 nm and are therefore capable of scattering visible light, providing the earliest evidence of structural colors in the insect fossil record. Optical modeling confirms that diffraction-related scattering mechanisms dominate the photonic properties of the fossil cover scales, which would have displayed broadband metallic hues as in numerous extant Micropterigidae. The fossil tarachopteran scales exhibit a unique suite of characteristics, including small size, elongate-spatulate shape, ridged ornamentation, and irregular arrangement, providing novel insight into the early evolution of lepidopteran scales. Combined, our results provide the earliest evidence for structural coloration in fossil lepidopterans and support the hypothesis that fused wing scales and the type 1 bilayer covering are groundplan features of the group. Wing scales likely had deep origins in earlier amphiesmenopteran lineages before the appearance of the Lepidoptera.", "keyphrases": ["early evolution", "lepidopteran", "structural color"]}
{"id": "paleo.001942", "title": "Harnessing stratigraphic bias at the section scale: conodont diversity in the Homerian (Silurian) of the Midland Platform, England", "abstract": "Fossil abundance and diversity in geological successions are subject to bias arising from shifting depositional and diagenetic environments, resulting in variable rates of fossil accumulation and preservation. In simulations, this bias can be constrained based on sequence\u2010stratigraphic architecture. Nonetheless, a practical quantitative method of incorporating the contribution of sequence\u2010stratigraphic architecture in community palaeoecology and diversity analyses derived from individual successions is missing. As a model of faunal turnover affected by the stratigraphic bias, we use the \u2018Mulde event\u2019, a postulated mid\u2010Silurian interval of elevated conodont turnover, which coincides with global eustatic sea\u2010level changes and which has been based on regionally constrained observations. We test whether conodont turnover is highest at the boundary corresponding to the \u2018event\u2019 and post\u2010\u2018event\u2019 interval against the alternative that conodont turnover reflects habitat tracking and peaks at facies shifts. Based on the previously documented, parasequence\u2010level stratigraphic framework of sections in the northern and central part of the Midland Platform, the relative controls of sequence\u2010stratigraphic architecture, time and depositional environment over conodont distribution are evaluated using permutational multivariate analysis of variance. The depositional environment controls the largest part of variability in conodont assemblage composition, whereas the postulated \u2018Mulde event\u2019, or genuine temporal change in conodont diversity, cannot be detected. Depending on the binning of the stratigraphic succession, contrasting diversity and turnover patterns can be produced. The simple approach proposed here, emulating partitioning of \u03b2 diversity into spatial and temporal components, may help to constrain the stratigraphic bias, even at the scale of an individual section.", "keyphrases": ["stratigraphic bias", "conodont diversity", "midland platform"]}
{"id": "paleo.005725", "title": "Fossil water\u2010penny beetles (Coleoptera: Psephenidae: Eubrianacinae) from the Eocene of Europe, with remarks on their phylogenetic position and biogeography", "abstract": "Abstract:\u2002 A species of water\u2010penny beetles is recorded from larval instars from the Middle Eocene Messel pit fossil site in Germany. This species clearly belongs to the psephenid subfamily Eubrianacinae, but its precise systematic affinities remain unclear. It is the second fossil species of this taxon recorded from Europe. The holotype of the first fossil species, Eubrianax vandeli Bertrand and Laurentiaux, 1963, is lost. The high number of fossil specimens from Messel allowed discussion of stratigraphic and spatial occurrence of the eubrianacine species in the Messel pit, but its larval ontogeny could not be unravelled. Because of the high number of fossils and their wide occurrence, it is inferred that the species from Messel gen. sp. 1 was an autochthonous faunal element of the Eocene Lake Messel, which might indicate that some parts of the former Lake Messel had a shore area with stones. The analysis of the phylogenetic position of both Eocene eubrianacine species showed that their phylogenetic placement cannot be resolved because preservational influences limit the evaluation of characters. The historical biogeography of Psephenidae and Eubrianacinae is analysed and discussed. The fossil record shows that psephenid beetles have fossil members occurring outside their current distribution range, so interpretations of their biogeography based only on extant members can be misleading.", "keyphrases": ["water\u2010penny beetle", "eubrianacinae", "biogeography"]}
{"id": "paleo.010735", "title": "Is amino acid racemization a useful tool for screening for ancient DNA in bone?", "abstract": "Many rare and valuable ancient specimens now carry the scars of ancient DNA research, as questions of population genetics and phylogeography require larger sample sets. This fuels the demand for reliable techniques to screen for DNA preservation prior to destructive sampling. Only one such technique has been widely adopted: the extent of aspartic acid racemization (AAR). The kinetics of AAR are believed to be similar to the rate of DNA depurination and therefore a good measure of the likelihood of DNA survival. Moreover, AAR analysis is only minimally destructive. We report the first comprehensive test of AAR using 91 bone and teeth samples from temperate and high-latitude sites that were analysed for DNA. While the AAR range of all specimens was low (0.02\u20130.17), no correlation was found between the extent of AAR and DNA amplification success. Additional heating experiments and surveys of the literature indicated that d/l Asx is low in bones until almost all the collagen is lost. This is because aspartic acid is retained in the bone within the constrained environment of the collagen triple helix, where it cannot racemize for steric reasons. Only if the helix denatures to soluble gelatin can Asx racemize readily, but this soluble gelatine is readily lost in most burial environments. We conclude that Asx d/l is not a useful screening technique for ancient DNA from bone.", "keyphrases": ["dna", "aspartic acid racemization", "dna survival", "burial environment"]}
{"id": "paleo.009963", "title": "Synchrotron \u201cvirtual archaeozoology\u201d reveals how Ancient Egyptians prepared a decaying crocodile cadaver for mummification", "abstract": "Although Ancient Egyptians mummified millions of animals over the course of one millennium, many details of these mummification protocols remain unknown. Multi-scale propagation phase-contrast X-ray synchrotron microtomography was used to visualise an ancient Egyptian crocodile mummy housed at the Mus\u00e9e des Confluences (Lyon, France). This state-of-the-art non-destructive imaging technique revealed the complete interior anatomy of the mummy in three dimensions. Here, we present detailed insight into the complex post-mortem treatment of a decaying crocodile cadaver in preparation for mummification. Except for the head and the extremities of the limbs, everything beneath the skin of the crocodile (i.e. organs, muscles, and even most of the skeleton) was removed to cease further putrefaction. This unexpected finding demonstrates that earlier knowledge obtained from textual and other archaeological sources does not sufficiently reflect the diversity of mummification protocols implemented by Ancient Egyptians.", "keyphrases": ["ancient egyptians", "crocodile cadaver", "mummification"]}
{"id": "paleo.010702", "title": "The earliest Tyrannida (Aves, Passeriformes), from the Oligocene of France", "abstract": "Passeriformes is the most diverse bird order. Nevertheless, passerines have a remarkably poor early fossil record. In addition, high osteological homoplasy across passerines makes partial specimens difficult to systematically assign precisely. Here we describe one of the few earliest fossil passerines, from the early Oligocene (ca 30 Ma) of southern France, and one of the best preserved and most complete. This fossil can be conservatively assigned to Tyrannida, a subclade of the New World Tyranni (Suboscines), i.e. of the Tyrannides. A most probably stem-representative of Tyrannida, the new fossil bears strong resemblance with some manakins (Pipridae), possibly due to plesiomorphy. Furthermore, it yields a new point of calibration for molecular phylogenies, already consistent with the age of the fossil. Tyrannida, and the more inclusive Tyrannides, are today confined to the New World. Therefore, the new fossil calls for scenarios of transatlantic crossing during or near the Oligocene. Later, the European part of the distribution of the Tyrannida disappeared, leading to a relictual modern New World distribution of this clade, a pattern known in other avian clades. The history of Tyrannida somehow mirrors that of the enigmatic Sapayoa aenigma, sole New World representative of the Eurylaimides (Old World Tyranni), with transatlantic crossing probably caused by similar events.", "keyphrases": ["tyrannida", "oligocene", "france"]}
{"id": "paleo.008038", "title": "Biometric analysis of the teeth of fossil and Recent hexanchid sharks and its taxonomic implications", "abstract": "A biometric analysis of the lower teeth of Recent cow sharks (Hexanchidae) investigates the ontogenetic and phylogenetic aspects of the dental characters employed by many ichthyologists and palaeontologists. The dental characters currently used to separate two extant species of sixgill sharks (Hexanchus griseus and H. nakamurai) are analysed and the fossil record of their relatives reviewed. The main results suggest that the cusp number ratio (number of cusps per mm) is preferable to width of the lower tooth for inference of total body size, at least in species of Hexanchus. The presence of a serrated edge or an enlarged acrocone appears to depend on ontogeny and care must be taken when using these as taxomomic characters. Three Eocene species of Hexanchus, H. collinsonae, H. hookeri, and H. agassizi, and a new assemblage of fossil teeth from the late Ypresian/early Lutetian (Early/Middle Eocene) of south-western France, are also analysed. The first two of these species may be ontogenetic states of H. agassizi. Hexanchus agassizi, belonging to the vituliform lineage and closely related to the living H. nakamurai, is considered here to be the only species of Hexanchus in the Lower to Middle Eocene. A brief overview of Palaeogene Hexanchus, suggests no evidence of the grisiform group (closely related to living H. griseus) before the Late Eocene.", "keyphrases": ["shark", "tooth", "biometric analysis"]}
{"id": "10.1080/02724631003758086", "title": "Tetrapod Fauna of the Lowermost Usili Formation (Songea Group, Ruhuhu Basin) of Southern Tanzania, with a New Burnetiid Record", "abstract": "ABSTRACT Vertebrate fossils from the Ruhuhu Basin of southern Tanzania have been known for over 75 years, but the details of their stratigraphic distribution remain imperfectly understood. Recent fleldwork in the Upper Permian Usili Formation (Songea Group) has led to the discovery of a tetrapod assemblage in a conglomeratic unit at its base. The fossils are concentrated in matrix-supported intraformational clay pebble conglomerates interpreted as mass flow deposits in wide, shallow channels in the distal reaches of an alluvial fan. Included in this new collection are fossils representing the first record of a burnetiid therapsid from Tanzania. The anatomy of the interorbital and intertemporal skull roof indicates that the Usili burnetiid most closely resembles Burnetia from the Dicynodon Assemblage Zone of South Africa's Beaufort Group. Review of the Usili Formation tetrapod fauna recognizes 29 genera, 6 of which are endemic (Katumbia, Kawingasaurus, Pachytegos, Peltobatrachus, Ruhuhucerberus, Titanogorgon, as well as a new, undescribed cryptodontian dicynodont). In addition, eight genera are shared between the basal conglomerate and rocks higher in section, which suggests that the available data fail to support the recognition of two faunal horizons within the Usili Formation, as was suggested previously. The recognition of a single (undivided) Usili tetrapod fauna calls for several therapsid genera to have unequal stratigraphic ranges (and temporal durations) in the Ruhuhu and Karoo basins. We suggest that the fine-scale biostratigraphic utility of therapsids likely diminishes between basins, especially when rates of subsidence, depositional setting, and paleoenvironment are taken into consideration.", "keyphrases": ["ruhuhu basin", "southern tanzania", "tetrapod fauna"]}
{"id": "10.1666/13036", "title": "Accurate and precise estimates of origination and extinction rates", "abstract": "Abstract Paleobiologists have used many different methods for estimating rates of origination and extinction. Unfortunately, all equations that consider entire age ranges are distorted by the Pull of the Recent, the Signor-Lipps effect, and simple edge effects. Attention has been paid recently to an equation of Foote's that considers counts of taxa either crossing the bottom and top of an interval or crossing one boundary but not the other. This generalized boundary-crosser (BC) method has important advantages but is still potentially subject to the major biases. The only published equation that circumvents all of them is the three-timer (3T) log ratio, which does so by focusing on a four-interval moving window. Although it is highly accurate it is noisy when turnover rates are very high or sampling is very poor. More precise values are yielded by a newly derived equation that uses the same counts. However, it also considers taxa sampled in a window's first and fourth intervals but missing from the third (i.e., gap-fillers). Simulations show that the 3T, gap-filler (GF), and BC equations yield identical values when sampling and turnover are uniform through time. When applied to Phanerozoic-scale marine animal data, 3T and GF agree well but the BC rates are systematically lower. The apparent reason is that (1) long-ranging but infrequently sampled genera are less likely to be split up by taxonomists and (2) the BC equation overweights taxa with long ranges. Thus, BC rates pertain more to rare genera that are likely to represent large clades whereas GF rates pertain more to actual species-level patterns. Given these results, all published turnover rates based either on genus-level data or on age ranges must be reconsidered because they may reflect taxonomic practices more strongly than the species-level dynamics of interest to biologists.", "keyphrases": ["origination", "extinction rate", "sampling"]}
{"id": "10.1080/08912963.2018.1431779", "title": "Teeth, fossil record and evolutionary history of the cowtail stingray Pastinachus R\u00fcppell, 1829", "abstract": "Abstract Hypolophin \u2018dasyatids\u2019 are a common group of large stingrays today frequenting the Indo-Pacific inshores. Being often harvested in their restricted area, few are known about their biology and their evolutionary history despite a very peculiar dental pattern making it easy to track their fossil record. An abundant material consisting of isolated teeth from Late Bartonian (38\u201340 Ma) lagoonal deposits of Djebel el K\u00e9bar, Tunisia, allows to describe a new stingray, Pastinachus kebarensis nov. sp. This taxon represents the oldest occurrence for this genus but also the oldest fossil record for hypolophins. A dental comparison of these fossils with 3D rendered models of fresh specimens testifies that early hypolophin representatives had already a strongly arcuate and bulbous upper jaw, interlocking with a broad and elongated tooth plate on the lower jaw. This new fossil and its fossil relatives (here updated), indicate a pre-Bartonian origination for hypolophins in western Neotethys, and reveal a rapid and widespread colonization of the proto-Mediterranean Sea, western Atlantic and Indo-Pacific coasts during the late Paleogene\u2013early Neogene. Finally, it is worth noting that early hypolophin representatives seemingly entered freshwater habitats occasionally as modern cowtail stingrays do.", "keyphrases": ["evolutionary history", "cowtail", "cowtail stingray", "tunisia", "tooth"]}
{"id": "10.1080/14772019.2015.1087064", "title": "Wading a lost southern connection: Miocene fossils from New Zealand reveal a new lineage of shorebirds (Charadriiformes) linking Gondwanan avifaunas", "abstract": "An endemic and previously unknown lineage of shorebirds (Charadriiformes: Scolopaci) is described from early Miocene (19\u201316 Ma) deposits of New Zealand. Hakawai melvillei gen. et sp. nov. represents the first pre-Quaternary record of the clade in New Zealand and offers the earliest evidence of Australasian breeding for any member of the Scolopaci. Hakawai melvillei was a representative of the clade that comprises the South American seedsnipes (Thinocoridae) and the Australian Plains-wanderer (Pedionomidae), and presumed derived features of its postcranial skeleton indicate a sister taxon relationship to Australian pedionomids. Our findings reinforce that terrestrial adaptations in seedsnipes and the Plains-wanderer are convergent as previously proposed, and support an ancestral wading ecology for the clade. Although vicariance events may have contributed to the split between pedionomids and H. melvillei, the proposed sister taxon relationship between these taxa indicates that the split of this lineage from thinocorids must have occurred independently from Australia and Zealandia's separation from the rest of Gondwana. http://zoobank.org/urn:lsid:zoobank.org:pub:FD3E50A9-EE95-4660-880A-A60B0DE2CEF4", "keyphrases": ["miocene", "shorebird", "charadriiformes"]}
{"id": "10.1111/jbi.12151", "title": "Greater past disparity and diversity hints at ancient migrations of European honey bee lineages into Africa and Asia", "abstract": "We re\u2010evaluated the proposition based on the present\u2010day distribution of honey bees (genus Apis) that their centre of origin resides in Asia, with subsequent migration and diversification into Europe and Asia. In our research, we considered the so\u2010far largely ignored fossils distributed through a variety of late Palaeogene (Oligocene) and early Neogene (Miocene) deposits, aiming at a synthesis of both present\u2010day and past honey bee distribution.", "keyphrases": ["migration", "africa", "asia", "europe"]}
{"id": "10.5479/si.00810266.94.1", "title": "Middle Proterozoic (1.5 Ga) Horodyskia moniliformis Yochelson and Fedonkin, the oldest known tissue-grade colonial eucaryote", "abstract": "Fedonkin, Mikhail A., and Ellis L. Yochelson. Middle Proterozoic (1.5 Ga) Horodyskia moniliformis Yochelson and Fedonkin, the Oldest Known Tissue-Grade Colonial Eucaryote. Smithsonian Contributions to Paleobiology, number 94, 29 pages, frontispiece, 19 figures, 2002.\u2014 \"Problematic bedding-plane markings\" discovered by the late R.J. Horodyski from the Appekunny Formation in Glacier National Park, Montana, and dated at approximately 1.5 giga-annum (Ga), were never formally named. We are convinced the specimens are biogenic and have placed them within Linnaean nomenclature as Horodyskia moniliformis Yochelson and Fedonkin. An apt description of the locally abundant fossils is \"string of beads.\" On each string, beads are of nearly uniform size and spacing; proportionally, bead size and spacing remain almost constant, regardless of string length or size of individual beads. They may not be related to any other known fossil, and their position within highest levels of the taxonomic hierarchy is enigmatic. We judge they were multicellular, tissue-grade, colonial eucaryotes. Similar strings have been reported from Western Australia, but nowhere else. The general geologic setting in Montana, details of sedimentation, and taphonomy suggest the organisms were benthonic, growing upward about 1 cm through episodically deposited eolian dust. During life, specimens were stiff and relatively strong, but show no evidence of a mineralized skeleton. They lived in poorly oxygenated water with the body progressively subjected to anaerobic conditions. Their energy source is obscure; their mode of growth and several features of interpreted environment lead us to speculate that Horodyskia likely lived primarily by ingesting chemosynthetic bacteria rather than by photosynthesis. This notion should be tested by searching red, fine-grained, subaqueous arenites of approximately the same age throughout the world for additional occurrences. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Annals of the Smithsonian Institution. SERIES COVER DESIGN: The trilobite Phacops rana Green. Fedonkin, M. A. (Mikhail Aleksandrovich) Middle Proterozoic (1.5 Ga) Horodyskia moniliformis Yochelson and Fedonkin, the oldest known tissue-grade colonial eucaryote / Mikhail A. Fedonkin and Ellis L. Yochelson. p. cm. \u2014 (Smithsonian contributions to paleobiology ; no. 94) Includes bibliographic references. 1. Horodyskia moniliformis\u2014Montana. 2. Paleontology\u2014Proterozoic. 3. Fossils\u2014Montana. I. Yochelson, Ellis Leon, 1928II. Title. III. Series.", "keyphrases": ["tissue-grade colonial eucaryote", "colonial eucaryote", "middle proterozoic"]}
{"id": "10.1111/j.1475-4983.2008.00761.x", "title": "A NEW PTEROSAUR FROM THE LIAONING PROVINCE OF CHINA, THE PHYLOGENY OF THE PTERODACTYLOIDEA, AND CONVERGENCE IN THEIR CERVICAL VERTEBRAE", "abstract": "Abstract:\u2002 The largest known flying organisms are the azhdarchid pterosaurs, a pterodactyloid clade previously diagnosed by the characters of their extremely elongate middle\u2010series cervical vertebrae. The named species of the Azhdarchidae are from the Late Cretaceous. However, isolated mid\u2010cervical vertebrae with similar dimensions and characters have been referred to this group that date back to the Late Jurassic, implying an almost 60 million year gap in the fossil record of this group and an unrecorded radiation in the Jurassic of all the major clades of the Pterodactyloidea. A new pterosaur from the Early Cretaceous of Liaoning Province of China, Elanodactylus prolatus gen. et sp. nov., is described with mid\u2010cervical vertebrae that bear these azhdarchid characters but has other postcranial material that are distinct from the members of this group. Phylogenetic analysis of the new species and the Pterodactyloidea places it with the Late Jurassic vertebrae in the Late Jurassic\u2013Early Cretaceous Ctenochasmatidae and reveals that the characters of the elongate azhdarchid vertebrae appeared independently in both groups. These results are realized though the large taxon sampling in the analysis demonstrating that the homoplastic character states present in these two taxa were acquired in a different order in their respective lineages. Some of these homoplastic characters were previously thought to appear once in the history of pterosaurs and may be correlated to the extension of the neck regions in both groups. Because the homoplastic character states in the Azhdarchidae and Ctenochasmatidae are limited to the mid\u2010cervical vertebrae, these states are termed convergent based on a definition of the term in a phylogenetic context. A number of novel results from the analysis presented produce a reorganization in the different species and taxa of the Pterodactyloidea.", "keyphrases": ["new pterosaur", "phylogeny", "pterodactyloidea"]}
{"id": "paleo.009657", "title": "Fossil-Informed Models Reveal a Boreotropical Origin and Divergent Evolutionary Trajectories in the Walnut Family (Juglandaceae)", "abstract": "Abstract Temperate woody plants in the Northern Hemisphere have long been known to exhibit high species richness in East Asia and North America and significantly lower diversity in Europe, but the causes of this pattern remain debated. Here, we quantify the roles of dispersal, niche evolution, and extinction in shaping the geographic diversity of the temperate woody plant family Juglandaceae (walnuts and their relatives). Integrating evidence from molecular, morphological, fossil, and (paleo)environmental data, we find strong support for a Boreotropical origin of the family with contrasting evolutionary trajectories between the temperate subfamily Juglandoideae and the tropical subfamily Engelhardioideae. Juglandoideae rapidly evolved frost tolerance when the global climate shifted to ice-house conditions from the Oligocene, with diversification at high latitudes especially in Europe and Asia during the Miocene. Subsequent range contraction at high latitudes and high levels of extinction in Europe driven by global cooling led to the current regional disparity in species diversity. Engelhardioideae showed temperature conservatism while adapting to increased humidity, tracking tropical climates to low latitudes since the middle Eocene with comparatively little diversification, perhaps due to high competition in the tropical zone. The biogeographic history of Juglandaceae shows that the North Atlantic land bridge and Europe played more critical roles than previously thought in linking the floras of East Asia and North America, and showcases the complex interplay among climate change, niche evolution, dispersal, and extinction that shaped the modern disjunct pattern of species richness in temperate woody plants. [Boreotropical origin; climatic niche evolution; disjunct distribution; dispersal; diversity anomaly; extinction; Juglandaceae.]", "keyphrases": ["boreotropical origin", "walnut", "juglandaceae", "asia", "europe"]}
{"id": "10.1002/ajpa.1330650407", "title": "Rib lesions in chronic pulmonary tuberculosis.", "abstract": "The diagnosis of skeletal tuberculosis in human remains has traditionally been based upon the detection of secondary skeletal lesions which result from hemotogenous dissemination of tubercle bacilli (e.g., Pott's disease). Since such lesions develop in less than 7% of cases of human tuberculosis, the paleodemography and paleoepidemiology of this disease have been difficult to assess from skeletal remains. This study presents a new diagnostic approach to tuberculosis, focusing on the skeletal manifestations of chronic pulmonary disease (which comprises approximately 90% of human-form tuberculosis). Four hundred forty-five skeletal remains from persons dying of tuberculosis during the first half of the 20th century were examined. A total of 70/445 (16%) exhibited skeletal lesions in one or more locations as a response to infection. Of these 70, 39 (56%) were found to display a specific set of lesions restricted to the internal aspect of the ribs. These lesions take one of two forms: (1) diffuse periostitis or (2) localized abscess, and appear to correspond to areas of chronic pulmonary infection. The diffuse type of rib lesion is more commonly observed than the localized type. In our observations (and according to the natural history of tuberculosis) the occurrence of chronic pulmonary tuberculosis is usually mutually exclusive with hematogenous dissemination to secondary bone locations. Thus, the detection of rib lesions in cases of chronic pulmonary disease increases the absolute sample size of skeletal tuberculosis by a factor of two in this study.", "keyphrases": ["pulmonary tuberculosis", "disease", "rib lesion"]}
{"id": "10.2110/palo.2010.p10-122r", "title": "TRIASSIC FLORAS OF ANTARCTICA: PLANT DIVERSITY AND DISTRIBUTION IN HIGH PALEOLATITUDE COMMUNITIES", "abstract": "ABSTRACT Continental Triassic sequences in Antarctica are among the most continuous and best represented in Gondwana. Triassic fossil plants have been collected sporadically from Antarctica since the beginning of the twentieth century, but our knowledge of the vegetation during this time has dramatically increased during the last three decades. Here we review the fossil record of Triassic plants as representatives of natural groups from sites along the Transantarctic Mountains, using the fossils as evidence for successive vegetational changes through the Triassic, taking into account that these plant communities were living under particular high-latitude (70\u00b0 or higher) paleoclimatological conditions, including a polar light regime. Even though our knowledge of the Triassic floras of Antarctica is still incomplete, this survey shows that these floras were remarkably diverse. Lycopsids, equisetaleans, ferns, seed ferns, ginkgoaleans, and conifers were major components of the landscape in Antarctica during this time. The diversity of gymnosperms is exceptional, with almost every major clade of seed plants present, despite the high paleolatitude; however, each clade is often represented by only one or a few genera. The occurrence of permineralized peat, along with compression-impression floras, has increased our knowledge of the morphology, reproductive biology, and evolution of many of the plants in these floras. In general, floral changes in Antarctica during the Triassic can be recognized elsewhere in Gondwana, especially in South America, although a strict correlation based on macrofossils is still not possible. Thus, this contribution represents the first attempt to bring together information on Triassic floras from continental Antarctica (excluding the Antarctic Peninsula) within a biostratigraphic framework and thereby to compare these floras with those from lower latitudes.", "keyphrases": ["antarctica", "vegetation", "conifer"]}
{"id": "10.1111/1475-4983.00320", "title": "Revision and re\u2010evaluation of the Early Jurassic dinosaurian ichnogenus Otozoum", "abstract": "Otozoum moodii Hitchcock, 1847 is one of the classic Connecticut Valley ichnotaxa established by Edward Hitchcock between 1836 and 1865. The taxon is redescribed, and AC 4/1a re\u2010established as the holotype specimen. Otozoum minus and O. caudatum are synonymised with O. moodii. The syntypes of Kalosauropus pollex (nomen nudum) are described as O. pollex sp. nov. Cladistic, quantitative, and comparative methods of trackmaker identification suggest that Otozoum was made by a prosauropod dinosaur. In quantitative analyses, only those phalanges likely to contribute to footprint morphology were considered; claws were also excluded due to their highly variable styles of impression. Several diagnostic characters distinguish Otozoum from Brachychirotherium, Chirotherium, Batrachopus, Tetrasauropus, and Pseudotetrasauropus; these ichnotaxa are probably attributable to crurotarsan archosaurs. Otozoum is found primarily in Hettangian strata of the Hartford, Deerfield, and Fundy rift basins of eastern North America; it is also present in the Early Jurassic Navajo Sandstone (Colorado Plateau, USA) and Clarens Formation (Lesotho). The taxon is unknown in older strata; Triassic material previously referred to Otozoum (including O. grandcombensis) instead belongs in Pseudotetrasauropus. Correlation of sediments and comparison of faunal assemblages, particularly within the Newark Supergroup, suggest that the Otozoum trackmakers were restricted to arid environments.", "keyphrases": ["otozoum", "ichnotaxa", "pseudotetrasauropus"]}
{"id": "10.1144/GSL.SP.2006.258.01.05", "title": "Cretaceous and Cenozoic vegetation of Antarctica integrating the fossil wood record", "abstract": "Abstract A compilation of data for Cretaceous and Cenozoic Antarctic fossil wood floras, predominantly from the James Ross Island Basin, provides a different perspective on floristic and vegetation change when compared with previous studies that have focused on leaf macrofossils or palynology. The wood record provides a filtered view of tree-forming elements within the vegetation, something that cannot be achieved from studies focusing on regional palynology or leaf floras. Four phases of vegetation development in the over-storey are recognized in the Cretaceous and Cenozoic of the Antarctic Peninsula based on the distribution and taxonomic composition of wood floras: Aptian-Albian coniferous forests; ?Cenomanian-Santonian mixed angiosperm forests; Campanian-Maastrichtian southern temperate forests; and Palaeocene-Eocene reduced diversity Nothofagus forests. Comparisons between the wood record and information derived from palynological and leaf floras have important implications for our understanding of the spatial composition of the vegetation. There is no doubt that climate change during the Cretaceous and Tertiary influenced the vegetational composition, but evolving palaeoenvironments in the Antarctic Peninsula region were probably of equal, if not greater, importance.", "keyphrases": ["vegetation", "antarctica", "diversification"]}
{"id": "10.1360/982005-575", "title": "A Miocene ostrich fossil from Gansu Province, northwest China", "abstract": "A pelvic skeleton, recognized as a large terrestrial bird in the field, was recently collected by our paleomammalogist colleagues from the Institute of Vertebrate Paleontology and Paleoanthropology from the late Miocene sandy mudstones in the Linxia Basin in Gansu Province, northwest China. We have further referred this bird to as an early representative of ostrich. Ostrich fossils usually coexisted with the famous Hipparion Fauna from the Miocene to Pliocene.", "keyphrases": ["miocene", "ostrich fossil", "northwest china"]}
{"id": "10.1017/jpa.2023.29", "title": "Morphology, variation, and systematics of the late Cambrian Laurentian dikelocephalid trilobite Walcottaspis vanhornei (Walcott, 1914)", "abstract": "\n Walcottaspis vanhornei (Walcott, 1914) is a large, late Cambrian trilobite with a unique pygidial morphology known only from a narrow outcrop belt of the St. Lawrence Formation in the Upper Mississippi Valley. Found in carbonate-rich layers within heterolithic facies that represent the toesets of a prograding shoreface, it is restricted to a single or small number of parasequences. Only four specimens of any of its sclerites have been illustrated previously. Here holaspid examples of all its biomineralized sclerites are described and illustrated, along with a morphometric analysis of cranidial landmarks and landmarks plus semilandmarks for the pygidium. Ontogenetic allometry accounts for 29% of the variance among holaspid cranidia and includes a relative shortening and narrowing of the palpebral lobe and a reduction in the relative length and width of the frontal area. Notable pygidial phenotypic variation occurs in the extent of the postaxial region and in the proportion of the structure occupied by the axis. Phylogenetic analysis suggests that W. vanhornei is sister taxon to Dikelocephalus minnesotensis Owen, 1852, which also occurs in the St. Lawrence Formation and has a broadly similar cephalon but distinctive trunk. The holaspid pygidium of W. vanhornei is uniquely characterized by the interpleural furrows of the first two segments becoming abruptly obsolete on approaching the axial furrow. Some pygidia show narrow, shallow, flat-bottomed grooves etched into the internal sides of the dorsal surface or doublure that apparently represent infestation of the live trilobite.", "keyphrases": ["trilobite", "walcottaspis vanhornei", "narrow outcrop belt", "morphology"]}
{"id": "paleo.005468", "title": "Microtoid cricetids and the early history of arvicolids (Mammalia, Rodentia)", "abstract": "In response to environmental changes in the Northern hemisphere, several lines of brachyodont-bunodont cricetid rodents evolved during the Late Miocene as \"microtoid cricetids.\" Major evolutionary trends include increase in the height of cheek tooth crowns and development of prismatic molars. Derived from a possible Megacricetodon or Democricetodon ancestry, highly specialised microtoid cricetids first appeared with Microtocricetus in the Early Vallesian (MN 9) of Eurasia. Because of the morphological diversity and degree of parallelism, phylogenetic relationships are difficult to detect. The Trilophomyinae, a more aberrant cricetid side branch, apparently became extinct without descendants. Two branches of microtoid cricetids can be recognized that evolved into \"true\" arvicolids: (1) Pannonicola (= Ischymomys) from the Late Vallesian (MN 10) to Middle Turolian (MN 12) of Eurasia most probably gave rise to the ondatrine lineage (Dolomys and Propliomys) and possibly to Dicrostonyx, whereas (2) Microtodon known from the Late Turolian (MN 13) and Early Ruscinian (MN 14) of Eurasia and possibly parts of North America evolved through Promimomys and Mimomys eventually to Microtus, Arvicola and other genera. The Ruscinian genus Tobienia is presumably the root of Lemmini. Under this hypothesis, in contrast to earlier views, two evolutionary sources of arvicolids would be taken into consideration. The ancestors of Pannonicola and Microtodon remain unknown, but the forerunner of Microtodon must have had a brachyodont-lophodont tooth crown pattern similar to that of Rotundomys bressanus from the Late Vallesian (MN 10) of Western Europe. Possibly, Pannonicola and Microtodon share a common ancestor. The fossil record suggests that an important center of origin for arvicolids was located in northeast Asia. From this region arvicolids could have dispersed to Europe and North America and vice versa during the late Cenozoic at various times.", "keyphrases": ["arvicolid", "north america", "asia", "microtoid cricetid"]}
{"id": "paleo.007395", "title": "Proterochampsa barrionuevoi (Archosauriformes: Proterochampsia) from the Late Triassic (Carnian) of Argentina and a phylogenetic analysis of Proterochampsia", "abstract": "Abstract:\u2002 Restudy of skulls and available postcrania of the proterochampsian archosauriform Proterochampsa barrionuevoi from the Ischigualasto Formation (Upper Triassic, Carnian) in the San Juan Province, Argentina, confirms that the genus is diagnosed by autapomorphies that include dermal sculpturing consisting of prominent ridges and nodular protuberances, a large hook\u2010like lateral projection on the quadratojugal, an antorbital fossa restricted to a depression along the maxilla, lateral expansion of the premaxilla anterior to the premaxilla\u2013maxilla contact, absence of a supratemporal fossa, exclusion of jugal from suborbital fenestra, basal tubera of parabasisphenoid facing ventrally and reaching laterally beyond the basipterygoid process, and a ventral lamina on the angular. Proterochampsa nodosa is a valid species distinguished from P. barrionuevoi by fewer cranial ridges with larger protuberances, relatively smaller supratemporal fenestrae and width of frontals between orbits less than that of the nasals. A phylogenetic analysis supports the monophyly of Proterochampsia consisting of Proterochampsa, Chanaresuchus bonapartei, Gualosuchus reigi, Tropidosuchus romeri and Cerritosaurus binsfeldi. A temporal separation between the two basal proterochampsians with earliest records in the Late Triassic (Proterochampsa and Cerritosaurus) and Chanaresuchus, Gualosuchus and Tropidosuchus in the Middle Triassic indicates hidden proterochampsian diversity in the Middle Triassic.", "keyphrases": ["proterochampsia", "late triassic", "phylogenetic analysis"]}
{"id": "paleo.004500", "title": "Stability, ranks, and the PhyloCode", "abstract": "Current codes of biological nomenclature define taxon names using types and ranks: the type determines the minimal membership of a named taxon, and the rank is supposed to determine its limits. Homo is \"the taxon including the type species Homo sapiens that is assigned to the rank of genus\". However, there is no \"genus concept\" (analogous to a species concept), and thus no way of empirically determining the limits of a particular genus, even in the context of a single agreed phylogeny. The same problems also apply to higher taxa at all other ranks under current codes, leading to great taxonomic instability. All proposed objective criteria for determining membership of taxa at a particular rank (e.g., geological age, genetic divergence) are shown to be problematic. In contrast, the clades named by phylogenetic definitions are objective and stable. Node-based and branchbased definitions are most precise; however, apomorphybased definitions can be ambiguous due to difficulty in defining alternative character states, and optimisation uncertainty. A major benefit of ranks (information about relative nesting of taxa) can be achieved even more efficiently using standardised but rankless suffixes already widely used in phylogenetic taxonomy. Finally, in situations where the phylogeny is poorly known, phylogenetic nomenclature appears to be superior to the Linnean system. Phylogenetic nomenclature does not force one to officially name poorly corroborated groupings, whereas Linnean codes compel users to erect and name genera even when relevant supraspecific relationships are poorly known.", "keyphrases": ["rank", "phylocode", "stability"]}
{"id": "10.13130/2039-4942/16131", "title": "EOMYIDS FROM THE RIBESALBES-ALCORA BASIN (EARLY MIOCENE, IBERIAN PENINSULA) AND THEIR BIOSTRATIGRAPHIC AND PALAEOECOLOGICAL IMPLICATIONS.", "abstract": "Two species of the family Eomyidae are identified in the Early Miocene localities of the Araia d\u2019Alcora outcrop (Ribesalbes-Alcora Basin, Iberian Peninsula): Ligerimys florancei and Ligerimys ellipticus. The first is rarer than the second, which is one of the most abundant mammals in the Ribesalbes-Alcora Basin assemblages. Due to its abundance, we are able to describe its variability in dental morphology, showing characteristics never previously observed, including the presence of a mesoloph or other features previously described only in ancient assemblages of this species, such as the presence of the anteroloph, which appears in younger assemblages in the Araia sequence. Furthermore, based on the eomyids, we divide the record of the Campisano Ravine section into two long local biozones, depending on the species present. In addition, each local biozone is divided into two smaller sub-biozones, depending on the abundance of each species. We retrospectively compare and correlate the assemblages studied here with other Ligerimys assemblages from the other basins in the Iberian Peninsula. We classify these sites based on the abundance and species of the genus Ligerimys. Additionally, we discuss the palaeoecological preferences of these species", "keyphrases": ["ribesalbes-alcora basin", "early miocene", "iberian peninsula", "ligerimys ellipticus", "early aragonian"]}
{"id": "paleo.001771", "title": "A bizarre Early Cretaceous enantiornithine bird with unique crural feathers and an ornithuromorph plough-shaped pygostyle", "abstract": "Enantiornithes are the most successful clade of Mesozoic birds. Here, we describe a new enantiornithine bird, Cruralispennia multidonta gen. et sp. nov., from the Protopteryx-horizon of the Early Cretaceous Huajiying Formation of China. Despite being among the oldest known enantiornithines, Cruralispennia displays derived morphologies that are unexpected at such an early stage in the evolution of this clade. A plough-shaped pygostyle, like that of the Ornithuromorpha, evolved convergently in the Cruralispennia lineage, highlighting the homoplastic nature of early avian evolution. The extremely slender coracoid morphology was previously unknown among Early Cretaceous enantiornithines but is common in Late Cretaceous taxa, indicating that by 131 million years ago this clade had already experienced considerable morphological differentiation. Cruralispennia preserves unusual crural feathers that are proximally wire-like with filamentous distal tips, a new morphotype previously unknown among fossil or modern feathers, further increasing the known diversity of primitive feather morphologies.", "keyphrases": ["enantiornithine bird", "crural feather", "plough-shaped pygostyle"]}
{"id": "10.1073/pnas.0906660106", "title": "The evolutionary history of the extinct ratite moa and New Zealand Neogene paleogeography", "abstract": "The ratite moa (Aves: Dinornithiformes) were a speciose group of massive graviportal avian herbivores that dominated the New Zealand (NZ) ecosystem until their extinction \u2248600 years ago. The phylogeny and evolutionary history of this morphologically diverse order has remained controversial since their initial description in 1839. We synthesize mitochondrial phylogenetic information from 263 subfossil moa specimens from across NZ with morphological, ecological, and new geological data to create the first comprehensive phylogeny, taxonomy, and evolutionary timeframe for all of the species of an extinct order. We also present an important new geological/paleogeographical model of late Cenozoic NZ, which suggests that terrestrial biota on the North and South Island landmasses were isolated for most of the past 20\u201330 Ma. The data reveal that the patterns of genetic diversity within and between different moa clades reflect a complex history following a major marine transgression in the Oligocene, affected by marine barriers, tectonic activity, and glacial cycles. Surprisingly, the remarkable morphological radiation of moa appears to have occurred much more recently than previous early Miocene (ca. 15 Ma) estimates, and was coincident with the accelerated uplift of the Southern Alps just ca. 5\u20138.5 Ma. Together with recent fossil evidence, these data suggest that the recent evolutionary history of nearly all of the iconic NZ terrestrial biota occurred principally on just the South Island.", "keyphrases": ["evolutionary history", "ratite moa", "moa", "terrestrial biota", "oligocene"]}
{"id": "paleo.010202", "title": "A New Integrated Approach to Taxonomy: The Fusion of Molecular and Morphological Systematics with Type Material in Benthic Foraminifera", "abstract": "A robust and consistent taxonomy underpins the use of fossil material in palaeoenvironmental research and long-term assessment of biodiversity. This study presents a new integrated taxonomic protocol for benthic foraminifera by unequivocally reconciling the traditional taxonomic name to a specific genetic type. To implement this protocol, a fragment of the small subunit ribosomal RNA (SSU rRNA) gene is used in combination with 16 quantitative morphometric variables to fully characterise the benthic foraminiferal species concept of Elphidium williamsoni Haynes, 1973. A combination of live contemporary topotypic specimens, original type specimens and specimens of genetic outliers were utilised in this study. Through a series of multivariate statistical tests we illustrate that genetically characterised topotype specimens are morphologically congruent with both the holotype and paratype specimens of E. williamsoni Haynes, 1973. We present the first clear link between morphologically characterised type material and the unique SSU rRNA genetic type of E. williamsoni. This example provides a standard framework for the benthic foraminifera which bridges the current discontinuity between molecular and morphological lines of evidence, allowing integration with the traditional Linnaean roots of nomenclature to offer a new prospect for taxonomic stability.", "keyphrases": ["taxonomy", "type material", "benthic foraminifera"]}
{"id": "10.1127/0077-7749/2010/0090", "title": "Bison remains from the Upper Siwaliks of Pakistan", "abstract": "Fossil remains ascribed to Bison cf. sivalensis are described in this paper. The material, discovered by the team of Palaeontology of the Punjab University, Lahore, Pakistan during the past few years comes from the Early \u2013 Middle Pliocene continental deposits of the Upper Siwaliks (Tatrot Formation, northern Pakistan) dated approximately from 3.3 to 2.6 Ma, and allows interesting comparisons with forms related to the origin of bisons. The new data significantly widens the timedistribution of the species and draws back the first appearance of Bison lineage in the Indian subcontinent.", "keyphrases": ["upper siwaliks", "pakistan", "bison"]}
{"id": "paleo.010215", "title": "Pleistocene Hominins as a Resource for Carnivores: A c. 500,000-Year-Old Human Femur Bearing Tooth-Marks in North Africa (Thomas Quarry I, Morocco)", "abstract": "In many Middle Pleistocene sites, the co-occurrence of hominins with carnivores, who both contributed to faunal accumulations, suggests competition for resources as well as for living spaces. Despite this, there is very little evidence of direct interaction between them to-date. Recently, a human femoral diaphysis has been recognized in South-West of Casablanca (Morocco), in the locality called Thomas Quarry I. This site is famous for its Middle Pleistocene fossil hominins considered representatives of Homo rhodesiensis. The bone was discovered in Unit 4 of the Grotte \u00e0 Hominid\u00e9s (GH), dated to c. 500 ky and was associated with Acheulean artefacts and a rich mammalian fauna. Anatomically, it fits well within the group of known early Middle Pleistocene Homo, but its chief point of interest is that the diaphyseal ends display numerous tooth marks showing that it had been consumed shortly after death by a large carnivore, probably a hyena. This bone represents the first evidence of consumption of human remains by carnivores in the cave. Whether predated or scavenged, this chewed femur indicates that humans were a resource for carnivores, underlining their close relationships during the Middle Pleistocene in Atlantic Morocco.", "keyphrases": ["resource", "carnivore", "morocco", "faunal accumulation", "tooth mark"]}
{"id": "10.1126/science.aaa4019", "title": "Sea-level rise due to polar ice-sheet mass loss during past warm periods", "abstract": "Warming climate, melting ice, rising seas We know that the sea level will rise as climate warms. Nevertheless, accurate projections of how much sea-level rise will occur are difficult to make based solely on modern observations. Determining how ice sheets and sea level have varied in past warm periods can help us better understand how sensitive ice sheets are to higher temperatures. Dutton et al. review recent interdisciplinary progress in understanding this issue, based on data from four different warm intervals over the past 3 million years. Their synthesis provides a clear picture of the progress we have made and the hurdles that still exist. Science, this issue 10.1126/science.aaa4019 Reconstructing past magnitudes, rates, and sources of sea-level rise can help project what our warmer future may hold. BACKGROUND Although thermal expansion of seawater and melting of mountain glaciers have dominated global mean sea level (GMSL) rise over the last century, mass loss from the Greenland and Antarctic ice sheets is expected to exceed other contributions to GMSL rise under future warming. To better constrain polar ice-sheet response to warmer temperatures, we draw on evidence from interglacial periods in the geologic record that experienced warmer polar temperatures and higher GMSLs than present. Coastal records of sea level from these previous warm periods demonstrate geographic variability because of the influence of several geophysical processes that operate across a range of magnitudes and time scales. Inferring GMSL and ice-volume changes from these reconstructions is nontrivial and generally requires the use of geophysical models. ADVANCES Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of sea-level rise. Advances in our understanding of polar ice-sheet response to warmer climates have been made through an increase in the number and geographic distribution of sea-level reconstructions, better ice-sheet constraints, and the recognition that several geophysical processes cause spatially complex patterns in sea level. In particular, accounting for glacial isostatic processes helps to decipher spatial variability in coastal sea-level records and has reconciled a number of site-specific sea-level reconstructions for warm periods that have occurred within the past several hundred thousand years. This enables us to infer that during recent interglacial periods, small increases in global mean temperature and just a few degrees of polar warming relative to the preindustrial period resulted in \u22656 m of GMSL rise. Mantle-driven dynamic topography introduces large uncertainties on longer time scales, affecting reconstructions for time periods such as the Pliocene (~3 million years ago), when atmospheric CO2 was ~400 parts per million (ppm), similar to that of the present. Both modeling and field evidence suggest that polar ice sheets were smaller during this time period, but because dynamic topography can cause tens of meters of vertical displacement at Earth\u2019s surface on million-year time scales and uncertainty in model predictions of this signal are large, it is currently not possible to make a precise estimate of peak GMSL during the Pliocene. OUTLOOK Our present climate is warming to a level associated with significant polar ice-sheet loss in the past, but a number of challenges remain to further constrain ice-sheet sensitivity to climate change using paleo\u2013sea level records. Improving our understanding of rates of GMSL rise due to polar ice-mass loss is perhaps the most societally relevant information the paleorecord can provide, yet robust estimates of rates of GMSL rise associated with polar ice-sheet retreat and/or collapse remain a weakness in existing sea-level reconstructions. Improving existing magnitudes, rates, and sources of GMSL rise will require a better (global) distribution of sea-level reconstructions with high temporal resolution and precise elevations and should include sites close to present and former ice sheets. Translating such sea-level data into a robust GMSL signal demands integration with geophysical models, which in turn can be tested through improved spatial and temporal sampling of coastal records. Further development is needed to refine estimates of past sea level from geochemical proxies. In particular, paired oxygen isotope and Mg/Ca data are currently unable to provide confident, quantitative estimates of peak sea level during these past warm periods. In some GMSL reconstructions, polar ice-sheet retreat is inferred from the total GMSL budget, but identifying the specific ice-sheet sources is currently hindered by limited field evidence at high latitudes. Given the paucity of such data, emerging geochemical and geophysical techniques show promise for identifying the sectors of the ice sheets that were most vulnerable to collapse in the past and perhaps will be again in the future. Peak global mean temperature, atmospheric CO2, maximum global mean sea level (GMSL), and source(s) of meltwater. Light blue shading indicates uncertainty of GMSL maximum. Red pie charts over Greenland and Antarctica denote fraction (not location) of ice retreat. Interdisciplinary studies of geologic archives have ushered in a new era of deciphering magnitudes, rates, and sources of sea-level rise from polar ice-sheet loss during past warm periods. Accounting for glacial isostatic processes helps to reconcile spatial variability in peak sea level during marine isotope stages 5e and 11, when the global mean reached 6 to 9 meters and 6 to 13 meters higher than present, respectively. Dynamic topography introduces large uncertainties on longer time scales, precluding robust sea-level estimates for intervals such as the Pliocene. Present climate is warming to a level associated with significant polar ice-sheet loss in the past. Here, we outline advances and challenges involved in constraining ice-sheet sensitivity to climate change with use of paleo\u2013sea level records.", "keyphrases": ["mass loss", "past warm period", "sea-level rise"]}
{"id": "10.1144/jm.23.1.67", "title": "Palaeocopida (Ostracoda) across the Permian\u2013Triassic events: new data from southwestern Taurus (Turkey)", "abstract": "The Palaeocopida have been considered as an entirely Palaeozoic group and their disappearance as a marker for the Palaeozoic\u2013Mesozoic boundary. Despite this, 11 Palaeocopida species have been recorded in the Early Triassic. New data obtained in southwestern Taurus at the Permian\u2013 Triassic section of \u00c7\u00fcr\u00fck da\u01e7, permit an assessment of this problem. This paper synthesizes the data on lowermost Triassic ostracodes and revises the youngest Palaecopida occurrences. A new Early Triassic Palaeocopida species is described (Reviya curukensis n. sp.).", "keyphrases": ["southwestern taurus", "turkey", "palaeocopida"]}
{"id": "paleo.008728", "title": "Implied weighting and its utility in palaeontological datasets: a study using modelled phylogenetic matrices", "abstract": "Implied weighting, a method for phylogenetic inference that actively seeks to downweight supposed homoplasy, has in recent years begun to be widely utilized in palaeontological datasets. Given the method's purported ability at handling widespread homoplasy/convergence, we investigate the effects of implied weighting on modelled phylogenetic data. We generated 100 character matrices consisting of 55 characters each using a Markov Chain morphology model of evolution based on a known phylogenetic tree. Rates of character evolution in these datasets were variable and generated by pulling from a gamma distribution for each character in the matrix. These matrices were then analysed under equal weighting and four settings of implied weights (k = 1, 3, 5, and 10). Our results show that implied weighting is inconsistent in its ability to retrieve a known phylogenetic tree. Equally weighted analyses are found to generally be more conservative, retrieving higher frequency of polytomies but being less likely to generate erroneous topologies. Implied weighting is found to generally resolve polytomies while also propagating errors, resulting in an increase in both correctly and incorrectly resolved nodes with a tendency towards higher rates of error compared to equal weighting. Our results suggest that equal weights may be a preferable method for parsimony analysis.", "keyphrases": ["weighting", "palaeontological dataset", "matrix"]}
{"id": "10.15184/aqy.2015.22", "title": "Shuidonggou localities 1 and 2 in northern China: archaeology and chronology of the Initial Upper Palaeolithic in north-east Asia", "abstract": "Shuidonggou localities 1 and 2 provide key evidence for the Initial Upper Palaeolithic of north-east Asia. In a recent article in Antiquity (87 (2013), 368\u2013383), Li et al. proposed a new chronology, building on the earlier results of Madsen et al. (Antiquity 75 (2001), 705\u2013716). Here Susan Keates and Yaroslav Kuzmin take issue with the new chronology. The article is followed by a response from Li and Gao.", "keyphrases": ["initial upper palaeolithic", "north-east asia", "shuidonggou locality"]}
{"id": "paleo.000577", "title": "Basal paravian functional anatomy illuminated by high-detail body outline", "abstract": "Body shape is a fundamental expression of organismal biology, but its quantitative reconstruction in fossil vertebrates is rare. Due to the absence of fossilized soft tissue evidence, the functional consequences of basal paravian body shape and its implications for the origins of avians and flight are not yet fully understood. Here we reconstruct the quantitative body outline of a fossil paravian Anchiornis based on high-definition images of soft tissues revealed by laser-stimulated fluorescence. This body outline confirms patagia-bearing arms, drumstick-shaped legs and a slender tail, features that were probably widespread among paravians. Finely preserved details also reveal similarities in propatagial and footpad form between basal paravians and modern birds, extending their record to the Late Jurassic. The body outline and soft tissue details suggest significant functional decoupling between the legs and tail in at least some basal paravians. The number of seemingly modern propatagial traits hint that feathering was a significant factor in how basal paravians utilized arm, leg and tail function for aerodynamic benefit.", "keyphrases": ["body outline", "fluorescence", "tissue detail"]}
{"id": "paleo.008368", "title": "The pharynx of the stem-chondrichthyan Ptomacanthus and the early evolution of the gnathostome gill skeleton", "abstract": "The gill apparatus of gnathostomes (jawed vertebrates) is fundamental to feeding and ventilation and a focal point of classic hypotheses on the origin of jaws and paired appendages. The gill skeletons of chondrichthyans (sharks, batoids, chimaeras) have often been assumed to reflect ancestral states. However, only a handful of early chondrichthyan gill skeletons are known and palaeontological work is increasingly challenging other pre-supposed shark-like aspects of ancestral gnathostomes. Here we use computed tomography scanning to image the three-dimensionally preserved branchial apparatus in Ptomacanthus, a 415 million year old stem-chondrichthyan. Ptomacanthus had an osteichthyan-like compact pharynx with a bony operculum helping constrain the origin of an elongate elasmobranch-like pharynx to the chondrichthyan stem-group, rather than it representing an ancestral condition of the crown-group. A mixture of chondrichthyan-like and plesiomorphic pharyngeal patterning in Ptomacanthus challenges the idea that the ancestral gnathostome pharynx conformed to a morphologically complete ancestral type.", "keyphrases": ["pharynx", "ptomacanthus", "gnathostome", "jawed vertebrate", "chondrichthyan"]}
{"id": "paleo.003296", "title": "Earliest signs of life on land preserved in ca. 3.5 Ga hot spring deposits", "abstract": "The ca. 3.48 Ga Dresser Formation, Pilbara Craton, Western Australia, is well known for hosting some of Earth's earliest convincing evidence of life (stromatolites, fractionated sulfur/carbon isotopes, microfossils) within a dynamic, low-eruptive volcanic caldera affected by voluminous hydrothermal fluid circulation. However, missing from the caldera model were surface manifestations of the volcanic-hydrothermal system (hot springs, geysers) and their unequivocal link with life. Here we present new discoveries of hot spring deposits including geyserite, sinter terracettes and mineralized remnants of hot spring pools/vents, all of which preserve a suite of microbial biosignatures indicative of the earliest life on land. These include stromatolites, newly observed microbial palisade fabric and gas bubbles preserved in inferred mineralized, exopolymeric substance. These findings extend the known geological record of inhabited terrestrial hot springs on Earth by B3 billion years and offer an analogue in the search for potential fossil life in ancient Martian hot springs.", "keyphrases": ["land", "volcanic caldera", "palisade fabric", "terrestrial hot spring"]}
{"id": "10.1002/oa.753", "title": "Carbon and nitrogen stable isotopes as tracers of change in diet breadth during Middle and Upper Palaeolithic in Europe", "abstract": "Carbon and nitrogen stable isotope ratios in fossil bone collagen have been used as evidence for an increase of diet breadth between Middle Palaeolithic Neanderthals and Early Upper Palaeolithic anatomically modern humans. In this paper, we revisit the rules of palaeodietary reconstruction using collagen stable isotopes and reassess the possible isotopic signatures of potential protein resources available to prehistoric humans. It appears that the interpretation of the human's isotopic signature does not necessarily imply a significant proportion of aquatic-derived protein in the diet neither for Neandertal nor for first anatomically modern humans in Europe. Exploitation of aquatic ecosystems by humans needs to be supported by further zooarchaeological evidence. Nevertheless, isotopic biogeochemistry of fossil human collagen can be very useful in palaeodietary reconstructions provided that basic rules are followed while selecting samples of coeval fauna, in order to establish the end members of different food resources. Significant progress investigating the evolution of subsistence strategies in fossil hominids is expected from a combination of zooarchaeological and isotopic data. Copyright \u00a9 2004 John Wiley & Sons, Ltd.", "keyphrases": ["stable isotope", "diet breadth", "carbon"]}
{"id": "10.7717/peerj.2075", "title": "Postcranial anatomy of Pissarrachampsa sera (Crocodyliformes, Baurusuchidae) from the Late Cretaceous of Brazil: insights on lifestyle and phylogenetic significance", "abstract": "The postcranial anatomy of Crocodyliformes has historically been neglected, as most descriptions are based solely on skulls. Yet, the significance of the postcranium in crocodyliforms evolution is reflected in the great lifestyle diversity exhibited by the group, with members ranging from terrestrial animals to semi-aquatic and fully marine forms. Recently, studies have emphasized the importance of the postcranium. Following this trend, here we present a detailed description of the postcranial elements of Pissarrachampsa sera (Mesoeucrocodylia, Baurusuchidae), from the Adamantina Formation (Bauru Group, Late Cretaceous of Brazil). The preserved elements include dorsal vertebrae, partial forelimb, pelvic girdle, and hindlimbs. Comparisons with the postcranial anatomy of baurusuchids and other crocodyliforms, together with body-size and mass estimates, lead to a better understanding of the paleobiology of Pissarrachampsa sera, including its terrestrial lifestyle and its role as a top predator. Furthermore, the complete absence of osteoderms in P. sera, a condition previously known only in marine crocodyliforms, suggests osteoderms very likely played a minor role in locomotion of baurusuchids, unlike other groups of terrestrial crocodyliforms. Finally, a phylogenetic analysis including the newly recognized postcranial features was carried out, and exploratory analyses were performed to investigate the influence of both cranial and postcranial characters in the phylogeny of Crocodyliformes. Our results suggest that crocodyliform relationships are mainly determined by cranial characters. However, this seems to be a consequence of the great number of missing entries in the data set with only postcranial characters and not of the lack of potential (or synapomorphies) for this kind of data to reflect the evolutionary history of Crocodyliformes.", "keyphrases": ["crocodyliformes", "baurusuchidae", "postcranial anatomy"]}
{"id": "10.1080/03115518.2015.1014737", "title": "Wombats (Vombatidae: Marsupialia) from the Pliocene Chinchilla Sand, southeast Queensland, Australia", "abstract": "Louys, J., 23.3.2015. Wombats (Vombatidae: Marsupialia) from the Pliocene Chinchilla Sand, southeast Queensland, Australia. Alcheringa 39, XXX\u2013XXX. ISSN 0311-5518 The Chinchilla Local Fauna is one of the richest Pliocene vertebrate fossil assemblages in Australia. However, Vombatidae material preserved in the Chinchilla Sand is very poorly known, and no systematic examination of the wombats from Chinchilla has been conducted. Here I review the cranio-dental and mandibular wombat remains derived from Chinchilla. This material includes both adults and pouch-young specimens. At least five species of wombats are preserved in the fluviatile Chinchilla deposits, although a lack of stratigraphically controlled excavations makes it impossible to determine whether all five species were sympatric. Several wombat taxa are revised: Sedophascolomys gen. nov. is formally erected to replace the invalid \u2018Phascolomys\u2019; Vombatus mitchelli (Owen) is recognized as a species distinct from Vombatus ursinus (Shaw), and is recorded for the first time from Chinchilla. In addition to Vombatus mitchelli, the Chinchilla Sand also preserves evidence of Phascolonus gigas, Ramsayia magna, Ramsayia lemleyi and Sedophascolomys medius. Julien Louys [julien.louys@anu.edu.au], Department of Archaeology and Natural History, School of Culture, History, and Languages, ANU College of Asia and the Pacific, The Australian National University, Canberra, ACT 2601, Australia.", "keyphrases": ["vombatidae", "marsupialia", "pliocene chinchilla sand"]}
{"id": "paleo.010173", "title": "A long-tailed marine reptile from China provides new insights into the Middle Triassic pachypleurosaur radiation", "abstract": "Pachypleurosaurs (Pachypleurosauroidea) are a group of small to medium-sized, lizard-like marine reptiles in the Early to Middle Triassic, including Pachypleurosauridae, Keichousauridae and closely related taxa. The group is generally considered as a sauropterygian radiation, but its phylogenetic interrelationships remain highly debated. Here, we present a new pachypleurosaurid, Honghesaurus longicaudalis gen. et sp. nov., from the early Middle Triassic (Anisian, ~ 244 Ma) marine deposits in Luxi, Yunnan, China. The discovery documents the first really long-tailed pachypleurosaur with totally 121 (69 caudal) vertebrae, providing new evidence for the vertebral multiplication and ecological adaption of this group. The long trunk associated with an incredibly long tail could provide Honghesaurus the advantage of maneuverability and energy efficiency for lateral undulatory swimming. Honghesaurus, although possessing a series of autapomorphies, fills the morphological gap between Qianxisaurus from the Ladinian Xingyi Biota and Wumengosaurus from the Anisian Panxian Biota. Phylogenetic studies unite these three pachypleurosaurids as a monophyletic clade above European pachypleurosaurid clades and provide new insights into the interrelationships of this group. Our scenario of pachypleurosaurian phylogeny combined with the stratigraphic data imply that the Tethys Ocean was a west\u2013east corridor for dispersal of pachypleurosaurids from Europe into South China.", "keyphrases": ["marine reptile", "china", "new insight", "pachypleurosaur", "honghesaurus"]}
{"id": "paleo.009842", "title": "Evidence for Neandertal Jewelry: Modified White-Tailed Eagle Claws at Krapina", "abstract": "We describe eight, mostly complete white-tailed eagle (Halia\u00ebtus [Haliaeetus] albicilla) talons from the Krapina Neandertal site in present-day Croatia, dating to approximately 130 kyrs ago. Four talons bear multiple, edge-smoothed cut marks; eight show polishing facets and/or abrasion. Three of the largest talons have small notches at roughly the same place along the plantar surface, interrupting the proximal margin of the talon blade. These features suggest they were part of a jewelry assemblage, --- the manipulations a consequence of mounting the talons in a necklace or bracelet. An associated phalanx articulates with one of the talons and has numerous cut marks, some of which are smoothed. These white-tailed eagle bones, discovered more than 100 years ago, all derive from a single level at Krapina and represent more talons than found in the entire European Mousterian period. Presence of eight talons indicates that the Krapina Neandertals acquired and curated eagle talons for some kind of symbolic purpose. Some have argued that Neandertals lacked symbolic ability or copied this behavior from modern humans. These remains clearly show that the Krapina Neandertals made jewelry well before the appearance of modern humans in Europe, extending ornament production and symbolic activity early into the European Mousterian.", "keyphrases": ["krapina", "phalanx", "eagle talon", "symbolic purpose"]}
{"id": "10.1148/rg.304095174", "title": "Scenes from the past: radiologic evidence of anthropogenic mummification in the Capuchin Catacombs of Palermo, Sicily.", "abstract": "The purpose of this study was to use paleoradiologic analyses to investigate a sample of the mummies in the Capuchin Catacombs in Palermo, Sicily, in order to assess skeletal abnormalities and the state of preservation, especially the condition of the internal organs, and to determine radiologic evidence of anthropogenic mummification. Ten 19th and early 20th century mummies with good external preservation were investigated by using a portable direct radiography unit inside the Capuchin Catacombs. The radiographs clearly demonstrated signs of anthropogenic mummification in nine of the 10 mummies investigated. The embalming methods that had been used included (a) evisceration and arterial injection; (b) the placement of foreign materials into the orbits and the nasal and oral cavities; and (c) filling of the thoracic, abdominal, and rectal cavities with foreign materials. Organ preservation varied greatly among the mummies, although brain tissue was found in all of the mummies. Analyses of the skeletal material of the mummies showed evidence of healed vertebral fractures, age-related degenerative changes, and, in one of the child mummies, a remarkable skeletal pathologic condition. The radiographs clearly illustrated different methods of anthropogenic mummification in the catacomb mummies of Palermo, allowed assessment of the preservation of the mummies, and demonstrated skeletal abnormalities.", "keyphrases": ["radiologic evidence", "anthropogenic mummification", "oral cavity", "thoracic"]}
{"id": "10.11646/zootaxa.3013.1.1", "title": "Lateral arm plate morphology in brittle stars (Echinodermata: Ophiuroidea): new perspectives for ophiuroid micropalaeontology and classification", "abstract": "Lateral arm plates, the spine-bearing plates of the ophiuroid arm skeleton, have long been assumed to display sufficient morphological diversity to be used for species identifications in ophiuroid micropalaeontology. As a consequence, many new brittle-star species have been described on the basis of isolated fossil lateral arm plates. A substantial lack of information on the morphological variability of lateral arm plates in respect of taxon concepts, however, has led to increasing confusion over species limits and excessive extensions of stratigraphic species ranges. In this study, we therefore performed a detailed assessment of the variability of lateral arm plate morphology within and between species in order to test to what extent isolated lateral arm plates can be used for species identifications. To this end, we investigated the morphological variability of lateral arm plates within species according to ontogenetic changes and according to the position of the plates along the arm. Furthermore, we examined the lateral arm plates of 56 Recent species, belonging to 27 genera and 10 families, and systematically assessed their morphology in the light of currently accepted taxon concepts. The results of this study demonstrate that lateral arm plate morphology is in accordance with most family, genus and species limits. Some of the currently accepted taxon concepts, including the affinities between the Ophiacanthidae and Ophiocomidae, however, are challenged by lateral arm plate morphology. Differences in lateral arm plate morphology between taxa are the most conspicuously displayed by adult proximal lateral arm plates, as a consequence of their high degree of differentiation compared to distal or juvenile lateral arm plates. Differences at species level, often pertain to characters which were considered to be within-species variation in previous micropalaeontological works, suggests that species identifications based on isolated fossil lateral arm plates require a much more detailed and careful morphological assessment. Some of the species studied herein displayed indistinguishable lateral arm plate morphologies, but belonged to the same genus in all cases. Our study endorses the use of isolated fossil lateral arm plates for taxonomic interpretations in ophiuroid micropalaeontology, including species identifications and the creation of new taxa, providing that descriptions are based on pristinely preserved adult proximal LAPs, described and illustrated using SEM-pictures of both the external and internal sides of the plate.", "keyphrases": ["arm plate morphology", "brittle star", "ophiuroid micropalaeontology"]}
{"id": "paleo.012719", "title": "Giant Mesozoic coelacanths (Osteichthyes, Actinistia) reveal high body size disparity decoupled from taxic diversity", "abstract": "The positive correlation between speciation rates and morphological evolution expressed by body size is a macroevolutionary trait of vertebrates. Although taxic diversification and morphological evolution are slow in coelacanths, their fossil record indicates that large and small species coexisted, which calls into question the link between morphological and body size disparities. Here, we describe and reassess fossils of giant coelacanths. Two genera reached up to 5 m long, placing them among the ten largest bony fish that ever lived. The disparity in body size adjusted to taxic diversity is much greater in coelacanths than in ray-finned fishes. Previous studies have shown that rates of speciation and rates of morphological evolution are overall low in this group, and our results indicate that these parameters are decoupled from the disparity in body size in coelacanths. Genomic and physiological characteristics of the extant Latimeria may reflect how the extinct relatives grew to such a large size. These characteristics highlight new evolutionary traits specific to these \u201cliving fossils\u201d.", "keyphrases": ["coelacanth", "body size disparity", "taxic diversity", "ray-finned fish"]}
{"id": "10.1073/pnas.1502932112", "title": "Gradual decline in mobility with the adoption of food production in Europe", "abstract": "Significance Declining mobility levels following the Pleistocene had profound effects on human demography, social organization, and health, but the exact timing and pace of this critical change are unknown. Here we examine direct evidence for changing mobility levels from limb bone structural characteristics in a large sample of European skeletons spanning the past 30,000 y. Our results show that mobility first declined during the Neolithic, at the onset of food production, but that the decline was gradual, continuing for several thousand years as agriculture intensified. No change in relative limb strength occurred during the past 2,000 y. Thus, the more gracile modern human skeleton is a result of increased sedentism tied to food production, not subsequent mechanization and industrialization. Increased sedentism during the Holocene has been proposed as a major cause of decreased skeletal robusticity (bone strength relative to body size) in modern humans. When and why declining mobility occurred has profound implications for reconstructing past population history and health, but it has proven difficult to characterize archaeologically. In this study we evaluate temporal trends in relative strength of the upper and lower limb bones in a sample of 1,842 individuals from across Europe extending from the Upper Paleolithic [11,000\u201333,000 calibrated years (Cal y) B.P.] through the 20th century. A large decline in anteroposterior bending strength of the femur and tibia occurs beginning in the Neolithic (\u223c4,000\u20137,000 Cal y B.P.) and continues through the Iron/Roman period (\u223c2,000 Cal y B.P.), with no subsequent directional change. Declines in mediolateral bending strength of the lower limb bones and strength of the humerus are much smaller and less consistent. Together these results strongly implicate declining mobility as the specific behavioral factor underlying these changes. Mobility levels first declined at the onset of food production, but the transition to a more sedentary lifestyle was gradual, extending through later agricultural intensification. This finding only partially supports models that tie increased sedentism to a relatively abrupt Neolithic Demographic Transition in Europe. The lack of subsequent change in relative bone strength indicates that increasing mechanization and urbanization had only relatively small effects on skeletal robusticity, suggesting that moderate changes in activity level are not sufficient stimuli for bone deposition or resorption.", "keyphrases": ["decline", "mobility", "food production"]}
{"id": "10.1144/jgs2021-164", "title": "Innovatiocaris\n , a complete radiodont from the early Cambrian Chengjiang Lagerst\u00e4tte and its implications for the phylogeny of Radiodonta", "abstract": "\n The Palaeozoic radiodonts are important for understanding the evolution and ecology of early euarthropods. However, complete radiodont fossils are very rare, despite their central roles in understanding radiodont palaeobiology. Here we describe\n Innovatiocaris maotianshanensis\n gen. et sp. nov. in detail based on an iconic complete radiodont specimen from the early Cambrian Chengjiang Lagerst\u00e4tte of China. The head of\n I\n .\n maotianshanensis\n has a pair of stalked eyes, an ovate dorsal sclerite, a pair of frontal appendages composed of 11 distal articulated podomeres bearing spiky endites with only anterior auxiliary spines, and a putative triradial oral cone. The body possesses six anterior pairs of small differentiated neck flaps and ten posterior pairs of trunk flaps, with soft tissues including alimentary canal and musculature preserved. The tail includes a tail fan comprising three pairs of lateral blades and a pair of very long furcae. Another two new species,\n Innovatiocaris\n ? sp. and\n I\n .?\n multispiniformis\n sp. nov., are established based on the frontal appendages with different numbers of anterior auxiliary spines and are tentatively assigned to\n Innovatiocaris\n . Phylogenetic analysis retrieves\n Innovatiocaris\n as either a basal member of Hurdiidae or early-branching species of the non-hurdiid clade. Thus,\n Innovatiocaris\n provides new insights into the radiodont phylogeny and illuminates the early diversification of Radiodonta.\n \n \n Supplementary material:\n Supplementary figures, phylogenetic data matrix, and a character list for phylogenetic analysis are available at\n https://doi.org/10.6084/m9.figshare.c.6179300\n \n \n Thematic collection:\n This article is part of the Advances in the Cambrian Explosion collection available at:\n https://www.lyellcollection.org/topic/collections/advances-in-the-cambrian-explosion\n", "keyphrases": ["radiodont", "cambrian chengjiang lagerst\u00e4tte", "euarthropod", "phylogenetic analysis"]}
{"id": "10.2307/3283583", "title": "Nematode larvae in fossilized animal coprolites from lower and middle Pleistocene sites, central Italy.", "abstract": "Nematode larvae were found in mineralized animal coprolites collected in lower and middle Pleistocene sites, central Italy. Coprolites collected in 4 paleontological sites dated from 1.5 million years to 30,000 years ago were identified as of Hyaenidae (Mammalia, Carnivora). Checklists available for present-day Hyaenidae did not permit identification of the larvae found. This is one of the most ancient parasite findings in coprolites.", "keyphrases": ["animal coprolite", "middle pleistocene site", "nematode larvae"]}
{"id": "10.1017/qua.2020.87", "title": "Bone histology, palaeobiology, and early diagenetic history of extinct equids from Turkey", "abstract": "Abstract Bone histology has proved to be a valuable tool to obtain information about the palaeobiology and early taphonomic history of fossil vertebrates. However, there are still many extinct taxa for which bone histology studies could be applied to deduce information about their life history and early diagenetic changes. Here, we partially fill this gap by studying bone microstructure and bone micropreservation in the third metapodia of Hipparion and Equus recovered from several Miocene, Pliocene, and Pleistocene localities in Turkey. Our histological analysis reveals that most of the bone cortices under study are composed of a well-vascularized fibrolamellar bone. Furthermore, we record the presence of compact coarse cancellous bone in a Hipparion metatarsal. In terms of histological preservation, our findings provide supporting evidence that differences in moisture, oxygen, and/or temperature during fossilisation at the different localities impacted the quality of bone preservation. Bacterial bioerosion was extensive in the samples, and we also identified a specific tunnelling morphology that we tentatively consider to be damage caused by freshwater algae. The present study provides novel insight into the palaeobiology and early diagenetic history of extinct horses from Turkey and sets the stage for further research in this area.", "keyphrases": ["palaeobiology", "early diagenetic history", "turkey"]}
{"id": "10.5194/cp-9-2135-2013", "title": "Glacial fluctuations of the Indian monsoon and their relationship with North Atlantic climate: new data and modelling experiments", "abstract": "Abstract. Several paleoclimate records such as from Chinese loess, speleothems or upwelling indicators in marine sediments present large variations of the Asian monsoon system during the last glaciation. Here, we present a new record from the northern Andaman Sea (core MD77-176) which shows the variations of the hydrological cycle of the Bay of Bengal. The high-resolution record of surface water \u03b418O dominantly reflects salinity changes and displays large millennial-scale oscillations over the period 40 000 to 11 000 yr BP. Their timing and sequence suggests that events of high (resp. low) salinity in the Bay of Bengal, i.e. weak (resp. strong) Indian monsoon, correspond to cold (resp. warm) events in the North Atlantic and Arctic, as documented by the Greenland ice core record. We use the IPSL_CM4 Atmosphere-Ocean coupled General Circulation Model to study the processes that could explain the teleconnection between the Indian monsoon and the North Atlantic climate. We first analyse a numerical experiment in which such a rapid event in the North Atlantic is obtained under glacial conditions by increasing the freshwater flux in the North Atlantic, which results in a reduction of the intensity of the Atlantic meridional overturning circulation. This freshwater hosing results in a weakening of the Indian monsoon rainfall and circulation. The changes in the continental runoff and local hydrological cycle are responsible for an increase in salinity in the Bay of Bengal. This therefore compares favourably with the new sea water \u03b418O record presented here and the hypothesis of synchronous cold North Atlantic and weak Indian monsoon events. Additional sensitivity experiments are produced with the LMDZ atmospheric model to analyse the teleconnection mechanisms between the North Atlantic and the Indian monsoon. The changes over the tropical Atlantic are shown to be essential in triggering perturbations of the subtropical jet over Africa and Eurasia, that in turn affect the intensity of the Indian monsoon. These relationships are also found to be valid in additional coupled model simulations in which the Atlantic meridional overturning circulation (AMOC) is forced to resume.", "keyphrases": ["fluctuation", "monsoon", "north atlantic climate"]}
{"id": "10.1098/rsos.190548", "title": "Increase in metazoan ecosystem engineering prior to the Ediacaran\u2013Cambrian boundary in the Nama Group, Namibia", "abstract": "The disappearance of the soft-bodied Ediacara biota at the Ediacaran\u2013Cambrian boundary potentially represents the earliest mass extinction of complex life, although the precise driver(s) of this extinction remain unresolved. The \u2018biotic replacement\u2019 model proposes that an evolutionary radiation of metazoan ecosystem engineers in the latest Ediacaran profoundly altered marine palaeoenvironments, resulting in the extinction of Ediacara biota and setting the stage for the subsequent Cambrian Explosion. However, metazoan ecosystem engineering across the Ediacaran\u2013Cambrian transition has yet to be quantified. Here, we test this key tenet of the biotic replacement model by characterizing the intensity of metazoan bioturbation and ecosystem engineering in trace fossil assemblages throughout the latest Ediacaran Nama Group in southern Namibia. The results illustrate a dramatic increase in both bioturbation and ecosystem engineering intensity in the latest Ediacaran, prior to the Cambrian boundary. Moreover, our analyses demonstrate that the highest-impact ecosystem engineering behaviours were present well before the onset of the Cambrian. These data provide the first support for a fundamental prediction of the biotic replacement model, and evidence for a direct link between the early evolution of ecosystem engineering and the extinction of the Ediacara biota.", "keyphrases": ["metazoan ecosystem engineering", "ediacaran\u2013cambrian boundary", "namibia"]}
{"id": "10.5479/si.00810266.82.1", "title": "New superfamily and three new families of tetraodontiform fishes from the Upper Cretaceous : the earliest and most morphologically primitive plectognaths", "abstract": "Tyler, James C , and Lorenzo Sorbini. New Superfamily and Three New Families of Tetraodontiform Fishes from the Upper Cretaceous: The Earliest and Most Morphologically Primitive Plectognaths. Smithsonian Contributions to Paleobiology, number 82, 59 pages, 25 figures, 2 tables, 1996.\u2014Fishes of the order Tetraodontiformes previously have been known with assurance from as early as the Lower Eocene, about 55 MYA. Two Upper Cretaceous taxa, Protriacanthus d'Erasmo (1946) from Comen, Slovenia, about 90 MYA, and Plectocretacicus Sorbini (1979) from Hakel, Lebanon, about 95 MYA, were referred by their authors to the tetraodontiforms, respectively in the vicinity of triacanthoids and ostracioids. Both of these taxa were originally based on single specimens in which insufficient details of critical osteological features were exposed, and their familial and ordinal placement were open to question. Based on additional specimens now available, including acid preparations of several specimens of both species, we believe that they represent two new families (Protriacanthidae and Plectocretacicidae) of tetraodontiforms with numerous features that are more primitive than previously reported for the order. We describe a third taxon, the new genus Cretatriacanthus (and new family Cretatriacanthidae), based on a single specimen from the Upper Cretaceous of Nardd, Italy, about 70 MYA. It shares most of the numerous primitive features of Protriacanthus and Plectocretacicus. Although many of their features are primitive, all three of these Upper Cretaceous taxa possess the most salient derived features of tetraodontiforms (e.g., reduced number of vertebrae, no anal-fin spines, reduced number of pelvic-fin rays, absence of certain skull bones, and, when present, long posterior process of pelvis with its halves in close contact or fused). The three Upper Cretaceous taxa share four derived features (absence of teeth, modified scales around base of pelvic spine, presence of subocular shelf, and diminutive size) that unite them in a clade herein recognized as the superfamily Plectocretacicoidea, whereas all other tetraodontiforms (those from the Lower Eocene to present) are united by seven derived features. Within the Plectocretacicoidea, five derived features support the sister-group relationship of Protriacanthus and Plectocretacicus. Each of the three Upper Cretaceous taxa has a mosaic of primitive and specialized features, with some of the latter being independently derived relative to similar features of triacanthoids, balistoids, and ostracioids. The evidence indicates that the Plectocretacicoidea (presently known from 70 to 95 MYA) are the morphologically primitive sister group of all other tetraodontiforms (presently known from 55 MYA to Recent). OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The trilobite Phaecops rana Green. Library of Congress Cataloging-in-Publication Data Tyler, James C , 1935New superfamily and three new families of tetraodontiform fishes from the Upper Cretaceous . the earliest and most morphologically primitive plectognaths / James C. Tyler and Lorenzo Sorbini. p. cm. \u2014 (Smithsonian contributions to paleobiology ; no. 82) Includes bibliographical references. 1. Cretatriacanthus guidotti. 2. Plectocretacicus clarae. 3. Protriacanthus gortanii. 4. Paleontology\u2014 Cretaceous. 5. Fishes, Fossil. I. Sorbini, Lorenzo. II. Title. III. Series. QE701.S56 no. 82 [QE852.T48] 560 s\u2014dc20 [567\\5] 95-46251 \u00a9 The paper used in this publication meets the minimum requirements of the American National Standard for Permanence of Paper for Printed Library Materials Z39.48\u20141984.", "keyphrases": ["new family", "tetraodontiform fish", "primitive plectognath"]}
{"id": "10.1080/03115518.2016.1180806", "title": "The phylogenetic relevance of the sacrum among macronarian sauropods: insights from a pelvis from the Upper Cretaceous of Patagonia, Argentina", "abstract": "Filippini, F.S., Otero, A. & Gasparini, Z., June 2016. The phylogenetic relevance of the sacrum among macronarian sauropods: insights from a pelvis from the Upper Cretaceous of Patagonia, Argentina. Alcheringa 41, xxx\u2013xxx. ISSN 0311-5518. Anatomical variation in the sacrum is useful for differentiating sauropod lineages. Morphological variation in the sacrum has been underestimated mainly because of its anatomical complexity and uncertain homologies with presacral and postsacral elements. We describe a titanosaurian sauropod pelvis (MLP 46-VIII-21-2) from Plottier (Neuqu\u00e9n Province, Argentina) collected in the 1940s from Coniacian\u2013Santonian (Upper Cretaceous) strata. The degree of bone fusion in the specimen (fused vertebral centra forming a single rod, with neural arches fused to the corresponding centrum and to adjacent neural arches) indicates a late ontogenetic age. The presence of a space between the first vertebra and the anterior margin of the illium, together with a scar located on the anterior part of the preactabular process, suggest the possible presence of a sixth sacral vertebra (putative dorsosacral additional characters present in the ilium point towards affinities with Titanosauria. The completeness and good preservation of the specimen allowed us to track features along the sacral series and to compare characters with other sauropods. Within a phylogenetic context, and based on the pattern present in basal sauropodomorphs, the presence of three sacral elements attached to the rim of the acetabulum in eusauropods opens the possibility for considering such elements as primordial sacrals. Florencia S. Filippini [florencia304@live.com.ar], Divisi\u00f3n Paleontolog\u00eda de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, La Plata, 1900, Bs. As., Argentina; Alejandro Otero [alexandros.otero@gmail.com]; Zulma Gasparini [zgaspari@fcnym.unlp.edu.ar] CONICET\u2014Divisi\u00f3n Paleontolog\u00eda de Vertebrados, Museo de La Plata, Paseo del Bosque s/n, La Plata, 1900, Bs. As., Argentina.", "keyphrases": ["phylogenetic relevance", "sacrum", "macronarian sauropod"]}
{"id": "10.1080/02724634.2010.501449", "title": "Mylodon darwini Owen (Xenarthra, Mylodontinae) from the Late Pleistocene of Mesopotamia, Argentina, with Remarks on Individual Variability, Paleobiology, Paleobiogeography, and Paleoenvironment", "abstract": "ABSTRACT The subfamily Mylodontinae, typified by Mylodon, is known from the Colloncuran (late Miocene of Patagonia, Argentina) to the late Pleistocene of South America and North America. Mylodontinae have been recorded during the Pleistocene of Argentina, including the genera Glossotherium, Paraglossotherium, Lestodon, and Mylodon, with Paraglossotherium and Mylodon not as well known as the other genera. In Argentina there have been traditionally four species of Mylodon, M. darwini, M. zeballozi, M. listai, and M. insigne, although the validity of some has been considered doubtful. A nearly complete skull with an associated mandible of Mylodon darwini from the late Pleistocene of Mesopotamia, Argentina, is described. The specimen represents the first record of the species in the Mesopotamian region. The morphometric analysis indicates that M. darwini had greater individual variability than previously thought. Although based on the results of the morphologic and morphometric analysis, the idea of sexual dimorphism for M. darwini is, for the time being, unwarranted. This new record also supports the idea that Mylodon had great ecological tolerance and was capable of inhabiting climates ranging from cold and arid to warm and humid, and even montane environments.", "keyphrases": ["mylodontinae", "late pleistocene", "mesopotamia"]}
{"id": "10.1126/science.aba9572", "title": "Origins and genetic legacy of prehistoric dogs", "abstract": "Dog domestication was multifaceted Dogs were the first domesticated animal, likely originating from human-associated wolves, but their origin remains unclear. Bergstrom et al. sequenced 27 ancient dog genomes from multiple locations near to and corresponding in time to comparable human ancient DNA sites (see the Perspective by Pavlidis and Somel). By analyzing these genomes, along with other ancient and modern dog genomes, the authors found that dogs likely arose once from a now-extinct wolf population. They also found that at least five different dog populations \u223c10,000 years before the present show replacement in Europe at later dates. Furthermore, some dog population genetics are similar to those of humans, whereas others differ, inferring a complex ancestral history for humanity's best friend. Science, this issue p. 557; see also p. 522 Ancient dog genomes elucidate diversification and a complex genetic history relative to that of humans. Dogs were the first domestic animal, but little is known about their population history and to what extent it was linked to humans. We sequenced 27 ancient dog genomes and found that all dogs share a common ancestry distinct from present-day wolves, with limited gene flow from wolves since domestication but substantial dog-to-wolf gene flow. By 11,000 years ago, at least five major ancestry lineages had diversified, demonstrating a deep genetic history of dogs during the Paleolithic. Coanalysis with human genomes reveals aspects of dog population history that mirror humans, including Levant-related ancestry in Africa and early agricultural Europe. Other aspects differ, including the impacts of steppe pastoralist expansions in West and East Eurasia and a near-complete turnover of Neolithic European dog ancestry.", "keyphrases": ["dog", "domestication", "wolf", "ancestry", "paleolithic"]}
{"id": "10.1111/j.1475-4983.2009.00899.x", "title": "Schischcatella (Fenestrata, Bryozoa) from the Devonian of the Rhenish Massif, Germany", "abstract": "Abstract:\u2002 The Devonian fenestrate bryozoan, Schischcatella Waschurova, 1964 , possessed colonies in the form of low, erect bifoliate fronds that grew from an encrusting sheet\u2010like base with autozooecia arranged in biserial, bifurcating rows. This growth habit is unique in fenestrates, which normally had unilaminate arborescent colonies. Originally, Schischcatella was described from the Lower Devonian of Tajikistan. This article describes a new species, S. heinorum sp. nov., from the Middle Devonian of the Eifel (western Rhenish Massif, Germany) with additional material from the Lower Devonian of the Kellerwald (eastern Rhenish Massif, Germany). External and internal morphologies of this bryozoan have been studied using abundant material. The growth habit of Schischcatella suggests a completely different pattern of feeding currents than that in the normal fenestrate colony. The outflow of the filtered water occurred only on edges of colonies between rami. In the absence of chimneys (areas of vertical water expelling), such a functional morphology may have restricted extension of the colony in a distal direction. The evolution of Schischcatella is apparently an example of paedomorphosis, the genus evolved from an unknown semicosciniid species by the early ontogenetic interruption of colony development and further changes in the mode of growth.", "keyphrases": ["germany", "bryozoan", "schischcatella"]}
{"id": "paleo.008124", "title": "Morphology and developmental traits of the trilobite Changaspis elongata from the Cambrian Series 2 of Guizhou, South China", "abstract": "The morphology and ontogeny of the trilobite Changaspis elongata based on 216 specimens collected from the Lazizhai section of the Balang Formation (Stage 4, Series 2 of the Cambrian) in Guizhou Province, South China are described. The relatively continuous ontogenetic series reveals morphological changes, and shows that the species has seventeen thoracic segments in the holaspid period, instead of the sixteen as previously suggested. The development of the pygidial segments shows that their number gradually decreases during ontogeny. A new dataset of well-preserved specimens offers a unique opportunity to investigate developmental traits after segment addition is completed. The ontogenetic size progressions for the lengths of cephalon and trunk show overall compliance with Dyar\u2019s rule. As a result of different average growth rates for the lengths of cephalon, trunk and pygidium, the length of the thorax relative to the body shows a gradually increasing trend; however, the cephalon and pygidium follow the opposite trend. Morphometric analysis across fourteen post-embryonic stages reveals growth gradients with increasing values for each thoracic segment from anterior to posterior. The reconstruction of the development traits shows visualization of the changes in relative growth and segmentation for the different body parts. The new dataset and growth gradient of the trunk suggest that the thoracic segment growth dynamics of early Cambrian to Silurian trilobites follow the same general continuous, steady-state growth gradient decreasing from posterior to anterior.", "keyphrases": ["developmental trait", "changaspis elongata", "morphology"]}
{"id": "10.1130/g23666a.1", "title": "Large-scale hydrological change drove the late Miocene C4 plant expansion in the Himalayan foreland and Arabian Peninsula", "abstract": "Carbon isotope changes in paleosols from Siwalik, Pakistan, and marine sediments from the Bengal Fan indicate a major C 4 plant expansion in the Himalayan foreland during the late Miocene. However, the timing and mechanisms behind the C 4 plant expansion remain enigmatic. Here we present high-resolution (\u223c60 k.y.) biomarker and compound-specific isotope data spanning the past 11 m.y. from Ocean Drilling Program Site 722 in the Arabian Sea. An \u223c5\u2030\u20136\u2030 increase in leaf wax \u03b4 13 C values indicates a marked rise of C 4 plants from 10 to 5.5 Ma, with accelerated expansion from 7.9 to 5.5 Ma. A concurrent \u223c50\u2030 rise in leaf wax \u03b4D values is attributed to a combined effect of changes in precipitation amount and evaporation, indicating that source regions for the plant waxes became progressively drier from 10 to 5.5 Ma. In contrast to earlier reports, our isotope records, biomarker abundances, alkenone U K\u2032 37 , and Globigerina bulloides abundance data do not suggest enhanced summer monsoon circulation during this time interval. Rather, our results suggest that large-scale hydrological changes drove the late Miocene expansion of C 4 plants in the Himalayan foreland and Arabian Peninsula.", "keyphrases": ["foreland", "arabian peninsula", "large-scale hydrological change"]}
{"id": "10.1086/423743", "title": "Evolution and Consequences of Endothermy in Fishes", "abstract": "Regional endothermy, the conservation of metabolic heat by vascular countercurrent heat exchangers to elevate the temperature of the slow\u2010twitch locomotor muscle, eyes and brain, or viscera, has evolved independently among several fish lineages, including lamnid sharks, billfishes, and tunas. All are large, active, pelagic species with high energy demands that undertake long\u2010distance migrations and move vertically within the water column, thereby encountering a range of water temperatures. After summarizing the occurrence of endothermy among fishes, the evidence for two hypothesized advantages of endothermy in fishes, thermal niche expansion and enhancement of aerobic swimming performance, is analyzed using phylogenetic comparisons between endothermic fishes and their ectothermic relatives. Thermal niche expansion is supported by mapping endothermic characters onto phylogenies and by combining information about the thermal niche of extant species, the fossil record, and paleoceanographic conditions during the time that endothermic fishes radiated. However, it is difficult to show that endothermy was required for niche expansion, and adaptations other than endothermy are necessary for repeated diving below the thermocline. Although the convergent evolution of the ability to elevate slow\u2010twitch, oxidative locomotor muscle temperatures suggests a selective advantage for that trait, comparisons of tunas and their ectothermic sister species (mackerels and bonitos) provide no direct support of the hypothesis that endothermy results in increased aerobic swimming speeds, slow\u2010oxidative muscle power, or energetic efficiency. Endothermy is associated with higher standard metabolic rates, which may result from high aerobic capacities required by these high\u2010performance fishes to conduct many aerobic activities simultaneously. A high standard metabolic rate indicates that the benefits of endothermy may be offset by significant energetic costs.", "keyphrases": ["endothermy", "water temperature", "convergent evolution", "mackerel"]}
{"id": "paleo.002712", "title": "Enamel microstructure and mastication in Pyrotherium romeroi (Pyrotheria, Mammalia)", "abstract": "The South American ungulate Pyrotherium romeroi provides a new enamel type, ''Pyrotheriumenamel''. It is characterized by vertically oriented bands that differ from vertical Hunter-Schreger-bands in being wider and having a specific internal feather-like structure. The enamel is formed exclusively by prisms with keyholeshaped cross sections. This prism type occurs in Proboscidea, Taeniodonta and some Primates and thus evolved independently several times. A slight differentiation between trailing and leading edges was found in the schmelzmuster. In addition to scanning electron microscope examination, the ''reflecting light method'' was applied, especially for the investigation of more extensive structures in the enamel microstructure. The mastication of Pyrotherium is dominated by phase I, which is directed mesially and steeply inclined. An insignificant lingually directed phase II without inclination was deduced from striations. The transverse lophs are very resistant to wear and retain their shear-cutting function for most of the lifetime. Whereas mastication in Pyrotherium is functionally comparable to that of other mammals with bilophodont dentitions, the enamel microstructure provides evidence for new unique morphological specializations in Pyrotheria and does not support connection to any other mammalian order so far discussed.", "keyphrases": ["mastication", "pyrotherium romeroi", "enamel microstructure"]}
{"id": "10.1080/03115518.2016.1184426", "title": "Systematics and palaeobiology of some Cambrian hyoliths from Guizhou, China, and Nevada, USA", "abstract": "Sun, H., Babcock, L.E., Peng, J. & Kastigar, J.M., July 2016. Systematics and palaeobiology of some Cambrian hyoliths from Guizhou, China, and Nevada, USA. Alcheringa 41, xxx\u2013xxx. ISSN 0311-5518. Hyoliths constitute one of the most important groups of early biomineralized metazoans. Abundant hyolith specimens, comprising both hyolithides and orthothecides, from the Balang Formation (Cambrian Stage 4), Guizhou, China, and the Poleta Formation (Cambrian Stages 3\u20134), Pioche Formation (Stages 4\u20135) and Emigrant Formation (Stages 4\u20135) Nevada, USA, add to the early Palaeozoic record of hyoliths from South China and Laurentia, and provide new taxonomic, taphonomic and palaeoecologic information about this group. Hyoliths from the Balang Formation include the hyolithides \u2018Ambrolinevitus\u2019 maximus Jiang, 1982, Galicornus seeneus? Val\u2019kov, 1975, Haplophrentis reesei Babcock & Robison, 1988, \u2018Linevitus\u2019 guizhouensis sp. nov., Meitanovitus guanyindongensis Qian, 1978, undetermined forms, and undetermined orthothecides. Hyoliths from Nevada include the hyolithides Haplophrentis carinatus (Matthew, 1899), Nevadotheca whitei (Resser, 1938), an undetermined form, and undetermined orthothecides. In the Balang Formation, eocrinoids have been found attached to hyolithide conchs, which supports the view that hyolithides were benthic animals. Haijing Sun* [hjsun1987@163.com], Resources and Environmental Engineering College, Guizhou University, Guiyang 550025, PR China; Loren E. Babcock\u2020 corresponding author [babcockloren@gmail.com], School of Earth Sciences, The Ohio State University, Columbus, OH 43210, USA; Jin Peng corresponding author [gzpengjin@126.com], Resources and Environmental Engineering College, Guizhou University, Guiyang 550025, PR China; Jessica M. Kastigar [kastigar.2@osu.edu], School of Earth Sciences, The Ohio State University, Columbus, OH 43210, USA. *Also affiliated with Key Laboratory of Economic Stratigraphy and Palaeogeography, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, PR China. \u2020Also affiliated with Department of Geology, Lund University, S\u00f6lvegatan 12, SE-223 62 Lund, Sweden.", "keyphrases": ["palaeobiology", "cambrian hyolith", "china"]}
{"id": "10.1017/S0094837300000336", "title": "Seafood through time: changes in biomass, energetics, and productivity in the marine ecosystem", "abstract": "The biomass of marine consumers increased during the Phanerozoic. This is indicated by the increase in both fleshiness and average size of individuals of dominant organisms, coupled with the conservative estimate that dominant organisms in the Cenozoic are at least as abundant as those in the Paleozoic. As faunal dominants replaced one another during the Phanerozoic the general level of metabolic activity increased due to both increase in basal metabolism and increase in more energetic modes of life. This demonstrates that the expenditure of energy by marine consumers has increased with time as well. There is a time lag in the expansion of more energetic life habits from environmental settings known to have high food supply into regions expected to have lower rates of food supply (e.g., bivalves into offshore carbonate environments or deep burrowing deposit feeders into the full range of shelf environments), and a time lag in diversification of energetic modes of life (e.g., predation or deep burrowing deposit feeding) for long intervals after they first appeared. This suggests that the supply of food increased across the whole spectrum of marine habitats during the Phanerozoic. The great diversification of specialized predators especially suggests that biomass increase took place all the way down the food chain to the level of primary production. The development of plant life on land and the impact of land vegetation on stimulating productivity in coastal marine settings, coupled with the transfer of organic material and nutrients from coastal regions to the open ocean, and the increase through time in diversity and abundance of oceanic phytoplankton all point to increased productivity in the oceans through the Phanerozoic.", "keyphrases": ["productivity", "food", "diversification"]}
{"id": "paleo.005036", "title": "Research history, taphonomy, and age structure of a mass accumulation of the ornithopod dinosaur Dysalotosaurus lettowvorbecki from the Upper Jurassic of Tanzania", "abstract": "The region around Tendaguru Hill in southeastern Tanzania has provided a rich, Late Jurassic dinosaur fauna. Among them, thousands of bones of the basal iguanodontian ornithopod Dysalotosaurus lettowvorbecki have been excavated in the Ig/WJ-quarry northwest of the Tendaguru Hill. The incomplete record of the taphonomic information from the excavation is the main reason for the still inconclusive interpretation of the assemblage as either catastrophic or attritional in origin. In this study, all available historical notes, sketches and field catalogues were analysed and combined with data from CT scans, new taphonomic observations and from bone histological as well as demographic analyses. According to these combined results, the mass accumulation of remains of D. lettowvorbecki consists of four closely associated bonebeds in at least three different stratigraphic levels. The bonebeds are classified as mixed, multitaxic, and monodominant. There is no evidence of abrasion and preburial weathering on the bones suggesting minimal transport distances and duration as well as short preburial exposure times. Although the size/age distributions are bimodally U-shaped, the bonebeds are interpreted as catastrophic in origin due to the restricted spatial extent and the overall uniform preservation of the bones. It is proposed that different herds of D. lettowvorbecki crossed a tidal channel several times during seasonal migration and that each time several to dozens of individuals died. The bodies decomposed and were buried at a barrier or a bend nearby. The demographic conditions as well as the modes of death and burial of D. lettowvorbecki are very similar to the observations made from the modern blue wildebeest in the Masai-Mara Reserve in Kenya. Dysalotosaurus lettowvorbecki , history, demography, taphonomy, Jurassic, Tendaguru, Africa.", "keyphrases": ["taphonomy", "mass accumulation", "dysalotosaurus lettowvorbecki", "tanzania", "stratigraphic level"]}
{"id": "10.1017/jpa.2016.37", "title": "Character evolution and the origin of Caimaninae (Crocodylia) in the New World Tropics: new evidence from the Miocene of Panama and Venezuela", "abstract": "Abstract \n Alligators and caimans share a close relationship, supported by both molecular and morphological characters. The divergence between alligators and caimans has been difficult to discern in the fossil record. Two basal taxa have recently been described from the Miocene of Panama and Venezuela but have not yet been presented in a joint phylogeny. Continued preparation of the type material of the Venezuelan Globidentosuchus brachyrostris Scheyer et al., 2013 has revealed new characters for scoring in a cladistic framework. In addition, the first lower jaw of the Panamanian Centenariosuchus gilmorei Hastings et al., 2013 is described herein, and additional characters were scored. In total, we conducted five cladistic analyses to better understand the character evolution involved in the establishment of Caimaninae. In each case, Globidentosuchus appears as the basal-most of the caimanine lineage, followed by Culebrasuchus mesoamericanus Hastings et al., 2013 from Panama. Stepwise character additions of synapomorphies define progressively more derived caimanines, but stratigraphic context creates ghost lineages extending from the Miocene to Paleocene. The persistence of two basal taxa into the Miocene of northern South America and Central America supports the concept of a relict basal population in this region. This further supports biogeographic hypotheses of dispersals in both directions between North and South America prior to full land connection.", "keyphrases": ["caimaninae", "miocene", "character evolution"]}
{"id": "10.1002/2017PA003201", "title": "BAYSPLINE: A New Calibration for the Alkenone Paleothermometer", "abstract": "The alkenone\u2010based U 37K\u2032 proxy is a cornerstone of paleoclimatology, providing insight into the temperature history of the Earth's surface ocean. Although the relationship between U 37K\u2032 and sea surface temperatures (SSTs) is robust and well supported by experimental data, there remain outstanding issues regarding the seasonality of production of alkenones and the response of U 37K\u2032 at very warm and cold SSTs. Using a data set of over 1,300 core\u2010top U 37K\u2032 measurements, we find compelling evidence of seasonal production in the North Atlantic, North Pacific, and Mediterranean Oceans. We also find significant attenuation of the U 37K\u2032 response to SST at warm temperatures (>24\u00b0C), with the slope reduced by nearly 50% as U 37K\u2032 approaches unity. To account for these observations in a calibration, we develop a new Bayesian B\u2010spline regression model, BAYSPLINE, for the U 37K\u2032 paleothermometer. BAYSPLINE produces similar estimates as previous calibrations below \u223c24\u00b0, but above this point it predicts larger SST changes, in accordance with the attenuation of the U 37K\u2032 response. Example applications of BAYSPLINE demonstrate that its treatment of seasonality and slope attenuation improves paleoclimatic interpretations, with important consequences for the inference of SSTs in the tropical oceans. BAYSPLINE facilitates a probabilistic approach to paleoclimate, building upon growing efforts to develop more formalized statistical frameworks for paleoceanographic reconstruction.", "keyphrases": ["calibration", "sst", "warm temperature", "bayspline"]}
{"id": "10.1371/journal.pone.0082668", "title": "More than One Way of Being a Moa: Differences in Leg Bone Robustness Map Divergent Evolutionary Trajectories in Dinornithidae and Emeidae (Dinornithiformes)", "abstract": "The extinct moa of New Zealand included three families (Megalapterygidae; Dinornithidae; Emeidae) of flightless palaeognath bird, ranging in mass from <15 kg to >200 kg. They are perceived to have evolved extremely robust leg bones, yet current estimates of body mass have very wide confidence intervals. Without reliable estimators of mass, the extent to which dinornithid and emeid hindlimbs were more robust than modern species remains unclear. Using the convex hull volumetric-based method on CT-scanned skeletons, we estimate the mass of a female Dinornis robustus (Dinornithidae) at 196 kg (range 155\u2013245 kg) and of a female Pachyornis australis (Emeidae) as 50 kg (range 33\u201368 kg). Finite element analysis of CT-scanned femora and tibiotarsi of two moa and six species of modern palaeognath showed that P. australis experienced the lowest values for stress under all loading conditions, confirming it to be highly robust. In contrast, stress values in the femur of D. robustus were similar to those of modern flightless birds, whereas the tibiotarsus experienced the highest level of stress of any palaeognath. We consider that these two families of Dinornithiformes diverged in their biomechanical responses to selection for robustness and mobility, and exaggerated hindlimb strength was not the only successful evolutionary pathway.", "keyphrases": ["moa", "dinornithidae", "emeidae"]}
{"id": "10.1126/sciadv.aar5040", "title": "Deglaciation of the Pacific coastal corridor directly preceded the human colonization of the Americas", "abstract": "Dating of rock surfaces and cave bones suggests the North Pacific coast was a viable path for human migration to the Americas. The route and timing of early human migration to the Americas have been a contentious topic for decades. Recent paleogenetic analyses suggest that the initial colonization from Beringia took place as early as 16 thousand years (ka) ago via a deglaciated corridor along the North Pacific coast. However, the feasibility of such a migration depends on the extent of the western Cordilleran Ice Sheet (CIS) and the available resources along the hypothesized coastal route during this timeframe. We date the culmination of maximum CIS conditions in southeastern Alaska, a potential bottleneck region for human migration, to ~20 to 17 ka ago with cosmogenic 10Be exposure dating and 14C dating of bones from an ice-overrun cave. We also show that productive marine and terrestrial ecosystems were established almost immediately following deglaciation. We conclude that CIS retreat ensured that an open and ecologically viable pathway through southeastern Alaska was available after 17 ka ago, which may have been traversed by early humans as they colonized the Americas.", "keyphrases": ["corridor", "colonization", "early human", "cordilleran ice sheet", "deglaciation"]}
{"id": "10.1086/321886", "title": "Mycobacterium tuberculosis complex DNA from an extinct bison dated 17,000 years before the present.", "abstract": "In order to assess the presence of tuberculosis in Pleistocene bison and the origin of tuberculosis in North America, 2 separate DNA extractions were performed by 2 separate laboratories on samples from the metacarpal of an extinct long-horned bison that was radiocarbon dated at 17,870+/-230 years before present and that had pathological changes suggestive of tuberculosis. Polymerase chain reaction amplification isolated fragments of tuberculosis DNA, which were sequenced, and on which spoligotyping was also performed to help determine its relationship to the various members of the Mycobacterium tuberculosis complex. Extensive precautions against contamination with modern M. tuberculosis complex DNA were employed, including analysis of paleontologic and modern specimens in 2 geographically separate laboratories.", "keyphrases": ["complex dna", "bison", "mycobacterium tuberculosis"]}
{"id": "10.1098/rstb.2015.0239", "title": "The transition to foraging for dense and predictable resources and its impact on the evolution of modern humans", "abstract": "Scientists have identified a series of milestones in the evolution of the human food quest that are anticipated to have had far-reaching impacts on biological, behavioural and cultural evolution: the inclusion of substantial portions of meat, the broad spectrum revolution and the transition to food production. The foraging shift to dense and predictable resources is another key milestone that had consequential impacts on the later part of human evolution. The theory of economic defendability predicts that this shift had an important consequence\u2014elevated levels of intergroup territoriality and conflict. In this paper, this theory is integrated with a well-established general theory of hunter\u2013gatherer adaptations and is used to make predictions for the sequence of appearance of several evolved traits of modern humans. The distribution of dense and predictable resources in Africa is reviewed and found to occur only in aquatic contexts (coasts, rivers and lakes). The palaeoanthropological empirical record contains recurrent evidence for a shift to the exploitation of dense and predictable resources by 110 000 years ago, and the first known occurrence is in a marine coastal context in South Africa. Some theory predicts that this elevated conflict would have provided the conditions for selection for the hyperprosocial behaviours unique to modern humans. This article is part of the themed issue \u2018Major transitions in human evolution\u2019.", "keyphrases": ["resource", "modern human", "africa", "coast", "south africa"]}
{"id": "paleo.012840", "title": "Dental Ontogeny in Pliocene and Early Pleistocene Hominins", "abstract": "Until recently, our understanding of the evolution of human growth and development derived from studies of fossil juveniles that employed extant populations for both age determination and comparison. This circular approach has led to considerable debate about the human-like and ape-like affinities of fossil hominins. Teeth are invaluable for understanding maturation as age at death can be directly assessed from dental microstructure, and dental development has been shown to correlate with life history across primates broadly. We employ non-destructive synchrotron imaging to characterize incremental development, molar emergence, and age at death in more than 20 Australopithecus anamensis, Australopithecus africanus, Paranthropus robustus and South African early Homo juveniles. Long-period line periodicities range from at least 6\u201312 days (possibly 5\u201313 days), and do not support the hypothesis that australopiths have lower mean values than extant or fossil Homo. Crown formation times of australopith and early Homo postcanine teeth fall below or at the low end of extant human values; Paranthropus robustus dentitions have the shortest formation times. Pliocene and early Pleistocene hominins show remarkable variation, and previous reports of age at death that employ a narrow range of estimated long-period line periodicities, cuspal enamel thicknesses, or initiation ages are likely to be in error. New chronological ages for SK 62 and StW 151 are several months younger than previous histological estimates, while Sts 24 is more than one year older. Extant human standards overestimate age at death in hominins predating Homo sapiens, and should not be applied to other fossil taxa. We urge caution when inferring life history as aspects of dental development in Pliocene and early Pleistocene fossils are distinct from modern humans and African apes, and recent work has challenged the predictive power of primate-wide associations between hominoid first molar emergence and certain life history variables.", "keyphrases": ["pliocene", "hominin", "dental development"]}
{"id": "paleo.006408", "title": "Trunk regionalization and functional morphology of the globally distributed trilobite Bathynotus from Cambrian Series 2 of China", "abstract": "This study presents a case in trunk regionalization and functional morphology of redlichiid trilobites, based on a globally distributed Bathynotus, collected from the base of the Kaili Formation in the late Cambrian Series 2 of China. This micropygous trilobite processed a body pattern with four types of thoracic tergites within two batches at maturity: a homonymous morphotype with similar thoracic tergite structure throughout the anterior portion of the thorax, and a heteronomous morphotype in the posterior portion of the thorax, with a pair of macropleurae in the 11th thoracic tergite and two pairs of tiny pleurae (micropleurae) in the 12th and 13th thoracic tergites. The unique morphology by regionalization in Bathynotusis considered closely related to its articulation structures and the ability to perform encapsulated enrolment, permitting the posterior trunk tergites with long pleural spines to fully cover the ventral cephalic shield during dorsal flexure. The regional integration of trunk tergites into structural regions provides the opportunity to trace the origin of their functional morphology and behavior in the evolutionary process of trilobite caudalization.", "keyphrases": ["functional morphology", "cambrian series", "trunk regionalization"]}
{"id": "paleo.010770", "title": "Collective behaviour in 480-million-year-old trilobite arthropods from Morocco", "abstract": "Interactions and coordination between conspecific individuals have produced a remarkable variety of collective behaviours. This co-operation occurs in vertebrate and invertebrate animals and is well expressed in the group flight of birds, fish shoals and highly organized activities of social insects. How individuals interact and why they co-operate to constitute group-level patterns has been extensively studied in extant animals through a variety mechanistic, functional and theoretical approaches. Although collective and social behaviour evolved through natural selection over millions of years, its origin and early history has remained largely unknown. In-situ monospecific linear clusters of trilobite arthropods from the lower Ordovician (ca 480 Ma) of Morocco are interpreted here as resulting either from a collective behaviour triggered by hydrodynamic cues in which mechanical stimulation detected by motion and touch sensors may have played a major role, or from a possible seasonal reproduction behaviour leading to the migration of sexually mature conspecifics to spawning grounds, possibly driven by chemical attraction (e.g. pheromones). This study confirms that collective behaviour has a very ancient origin and probably developed throughout the Cambrian-Ordovician interval, at the same time as the first animal radiation events.", "keyphrases": ["arthropod", "morocco", "collective behaviour"]}
{"id": "10.1017/S0094837300025574", "title": "Prey Selection by naticid gastropods: experimental tests and application to the fossil record", "abstract": "Because predation by drilling gastropods is uniquely preservable in the fossil record, it represents important evidence for the study of coevolution. Previous studies of drilling gastropod predation have been largely descriptive and sometimes contradictory. We formulate and test a model of prey selection by naticid drilling gastropods. The model adequately predicts both prey species selection and prey size selection. Prey preferences parallel prey profitabilities, determined by calculating prey species-specific and predator size-specific cost-benefit functions. The model also specifically suggests the evolution of potential refugia from predation and the evolution of potential predatory attributes. Application of the model to several Miocene and Pliocene assemblages studied by Thomas (1976) corroborates the feasibility and utility of this approach in examining the evolutionary record of naticid predation, which extends from the Late Mesozoic. Apparent evolutionary stasis and convergent morphological trends among prey species may be consistent with continuous selection pressures against predation.", "keyphrases": ["naticid gastropod", "application", "prey selection"]}
{"id": "paleo.000835", "title": "Mollistephaninae and Frebolditinae, new subfamilies of Middle Jurassic stephanoceratid Ammonoidea", "abstract": "Two new Bajocian stephanoceratid subfamilies are distinguished based on morpho-structural criteria and phyletic patterns. At the Aalenian/Bajocian transition, Stephanoceratinae of the genus Albarracinites are the source of the earliest species of Mollistephanus and of the new Mollistephaninae lineage that includes three successive genera: Mollistephanus, Paramollistephanus gen. nov. and Phaulostephanus. The Mollistephaninae span across the Mediterranean-Caucasian Subrealm during the lower Bajocian, but Paramollistephanus is pandemic to both the Mediterranean-Caucasian and East Pacific subrealms during the Propinquans Zone. The Frebolditinae evolved from Paramollistephanus in the lower Bajocian, beginning with Freboldites and giving rise to diverse genera such as Parabigotites, Patrulia, Bajocia, Subcollina and Parastrenoceras that occur into the upper Bajocian of both the East Pacific and Mediterranean-Caucasian subrealms.\nPalaeobiogeographical and phylogenetic data of these two subfamilies support an active Bajocian Central-Atlantic Seaway, the so-called Hispanic Corridor, as a bidirectional, biodispersal route driven by changes of the relative sea level. Several bioevents of appearance, immigration and dispersal, associated with the range expansion of ammonoid taxa, were effective (Paramollistephanus in the latest Laeviuscula Zone, Subcollina in the latest Humphriesianum Zone, and Parastrenoceras in the earliest Niortense Zone). Based on life-history strategy, morphostructural and functional criteria, the dimorphic Caumontisphinctes-Infraparkinsonia pair seems to be the origin of the Parkinsoniidae. The Mollistephaninae and Frebolditinae show small adult size, scarcity of fossils, and low stratigraphic persistence and constancy; however, they present some pandemic genera of the Tethys-Panthalassa Realm and display high resolution for time correlation between the western Tethyan and eastern Pacific marine basins of separate bioprovinces.", "keyphrases": ["frebolditinae", "subfamily", "mollistephaninae"]}
{"id": "10.7717/peerj.1306", "title": "Intraspecific variation of phragmocone chamber volumes throughout ontogeny in the modern nautilid Nautilus and the Jurassic ammonite Normannites", "abstract": "Nautilus remains of great interest to palaeontologists after a long history of actualistic comparisons and speculations on aspects of the palaeoecology of fossil cephalopods, which are otherwise impossible to assess. Although a large amount of work has been dedicated to Nautilus ecology, conch geometry and volumes of shell parts and chambers have been studied less frequently. In addition, although the focus on volumetric analyses for ammonites has been increasing recently with the development of computed tomographic technology, the intraspecific variation of volumetric parameters has never been examined. To investigate the intraspecific variation of the phragmocone chamber volumes throughout ontogeny, 30 specimens of Recent Nautilus pompilius and two Middle Jurassic ammonites (Normannites mitis) were reconstructed using computed tomography and grinding tomography, respectively. Both of the ontogenetic growth trajectories from the two Normannites demonstrate logistic increase. However, a considerable difference in Normannites has been observed between their entire phragmocone volumes (cumulative chamber volumes), in spite of their similar morphology and size. Ontogenetic growth trajectories from Nautilus also show a high variation. Sexual dimorphism appears to contribute significantly to this variation. Finally, covariation between chamber widths and volumes was examined. The results illustrate the strategic difference in chamber construction between Nautilus and Normannites. The former genus persists to construct a certain conch shape, whereas the conch of the latter genus can change its shape flexibly under some constraints.", "keyphrases": ["phragmocone chamber volume", "nautilus", "intraspecific variation"]}
{"id": "paleo.000754", "title": "Overview of Mesozoic crocodylomorphs from the Junggar Basin, Xinjiang, Northwest China, and description of isolated crocodyliform teeth from the Late Jurassic Liuhuanggou locality", "abstract": "Lacustrine and fluvial Jurassic and Cretaceous sediments in the Junggar Basin yielded at least five crocodylomorph taxa. The Middle and Late Jurassic Shishugou Formation has produced the crocodylomorph Junggarsuchus sloani, the holotype specimen of the middle-sized, amphibious goniopholidid Sunosuchus junggarensis, and remains of the shartegosuchid crocodyliform Nominosuchus matutinus. The contemporary Qigu Formation has also yielded Sunosuchus. Two crocodyliforms have been reported based on cranial and postcranial material from the Early Cretaceous Tugulu Group. The cranial material has been assigned to Edentosuchus tienshanensis, representing the geologically youngest protosuchid. In recent years, screenwashing at the Liuhuanggou locality, 40 km southwest of the city of Urumqi, has yielded a large number of isolated crocodyliform teeth in a highly fossiliferous bonebed within the Late Jurassic Qigu Formation. At least three different tooth morphologies can be distinguished at Liuhuanggou, indicating a shartegosuchid, juveniles cf. Sunosuchus and an unidentified mesoeucrocodylian. Thus, the variety in crocodyliforms known from this region is increased. The faunal composition comprises a mix of basal and derived crocodyliforms similar to that of the upper part of the Shishugou Formation and differs from contemporary European and many North American deposits. Hence, crocodyliform diversity in the Junggar Basin comprises at least two different size classes in the Junggar ecosystem: whereas the most frequently found taxon, Sunosuchus, was a larger (3 m) amphibious mesoeucrocodylian, the other taxa were smaller (<1.5 m long) and possibly more terrestrial faunal components. The combination of phylogenetically different crocodylomorphs and different ecotypes may reflect climate changes and hints towards the presence of relict faunas.", "keyphrases": ["crocodylomorph", "junggar basin", "crocodyliform tooth"]}
{"id": "10.1080/08912963.2018.1468441", "title": "The cave bear\u2019s hibernation: reconstructing the physiology and behaviour of an extinct animal", "abstract": "Abstract When studying an extinct species such as the cave bear (Ursus spelaeus ROSENM\u00dcLLER 1794), it is possible to apply a variety of molecular biology techniques such as the study of stable isotopes or mitochondrial DNA (mDNA) to infer patterns of behaviour or physiology that would otherwise remain concealed. Throughout Europe and along time, differences in the isotopic values (\u03b413C and \u03b415N) of cave bears arise from environmental differences and the Pleistocene climatic evolution. The climate determines the hibernation length, during which the cave bears undergo a particular physiology that can be related to an increase in \u03b415N during climate cooling. In order to verify whether hibernation affected the isotopic values, we compared cave bears in different ontogenetic stages. The results show that perinatal values reflect the values for mothers during hibernation, while juveniles show differences in maternal investment. A previous study in the literature based on complete mitochondrial DNA sequences of several individuals collected from closely situated caves showed that each cave housed, almost exclusively, a single lineage of haplotypes. This pattern suggests extreme fidelity to the birth site, or homing behaviour, and that cave bears formed stable maternal social groups, at least for the purpose of hibernation. Studies of this type offer unexpected data on the palaeobiology of this extinct animal.", "keyphrases": ["cave bear", "hibernation", "extinct animal"]}
{"id": "10.1126/science.abf5787", "title": "Early giant reveals faster evolution of large body size in ichthyosaurs than in cetaceans", "abstract": "Description Early marine giant The largest animals to have ever lived occupied the marine environment. Modern cetaceans evolved their large size over tens of millions of years in response to the increased productivity of cold marine waters. However, whales were not the first marine giants to evolve. Sander et al. describe a 244-million-year-old fossil ichthyosaur that would have rivaled modern cetaceans in size (see the Perspective by Delsett and Pyenson). The animal existed at most 8 million years after the emergence of the first ichthyosaurs, suggesting a much more rapid size expansion that may have been fueled by processes after the Permian mass extinction. \u2014SNV A 244-million-year-old fossil of a massive ichthyosaur suggests that there was a burst of gigantism in the group after the Permian extinction. INTRODUCTION The iterative evolution of secondarily marine tetrapods since the Paleozoic offers the promise of better understanding how the anatomy and ecology of animals change when returning to the sea. Recurring patterns of convergence in the geological past may suggest predictability of evolution when transitioning from full-time life on land to full-time life in the ocean. Ichthyosaurs (fish-shaped marine reptiles of the Mesozoic) and today\u2019s cetaceans (whales, dolphins, and porpoises) are two of the most informative lineages to exemplify secondary returns to the sea. The notable resemblance in body shape and lifestyle of ichthyosaurs and cetaceans contrasts with their separation in time by nearly 200 million years, providing an often-cited example of convergent evolution. Ichthyosaurs arose 249 million years ago and populated the oceans for the next 150 million years. Cetaceans did not evolve until about 56 million years ago. As tail-propelled swimmers, ichthyosaurs and cetaceans evolved not only convergent body shapes but also large body sizes. RATIONALE The integration of fossil and extant data can improve understanding of aquatic adaptation and gigantism as patterns of convergent evolution, particularly when interpreted in an ecological context. Our paleontological fieldwork in the Fossil Hill Member (Middle Triassic, Nevada, USA) provided the basis for the marine reptile data and resulted in finds of giant ichthyosaurs as part of the pelagic Fossil Hill Fauna. We compiled data for both fossil and living whales from the extensive literature. Together, these data provide the basis for computational analyses of maximum body size and its evolution over time. Modeling of energy flux in the Fossil Hill Fauna helps in understanding how the Fossil Hill ecosystem could have supported several large to giant tetrapod ocean consumers so early in ichthyosaur evolutionary history. RESULTS We describe an ichthyosaur with a 2-m-long skull from the Fossil Hill Fauna as a new species of Cymbospondylus. At present, this is the largest known tetrapod of its time, on land or in the sea, and is the first in a series of ocean giants. The Fossil Hill Fauna includes several other large-bodied ichthyosaurs in the Cymbospondylus radiation. The body-size range in this Triassic fauna rivals the range seen in modern whale faunas, from a total length of about 2 m in Phalarodon to more than 17 m in the new species. As preserved in the fossil record, the Fossil Hill Fauna represents a stable trophic network and could even have supported another large ichthyosaur if it bulk fed on small, but abundant, prey such as ammonoids. In absolute time, the new ocean giant lived 246 million years ago, only about 3 million years after the appearance of the first ichthyosaurs. Our research suggests that ichthyosaurs evolved large body size very early on in the clade\u2019s history, comparatively earlier than whales. CONCLUSION Ichthyosaurs and cetaceans both evolved very large body sizes, yet their respective evolutionary pathways toward gigantism were different. Ichthyosaurs seem to have benefited from the abundance of pelagic conodonts and ammonoids after the recovery from the end-Permian mass extinction, even in the absence of modern primary producers. Cetaceans took different routes, but all appear to be related to trophic specialization, including the loss of teeth in baleen whales (Mysticeti) and the evolution of raptorial feeding and deep diving in toothed whales (Odontoceti). Ichthyosaurs evolved large body sizes earlier in their history than cetaceans. The Fossil Hill Fauna of the Middle Triassic of Nevada, USA, is critical for recognizing this pattern. It features the first ocean giant among tetrapods, only 3 million years after ichthyosaurs first appeared. Whales took comparatively longer to attain similarly large body sizes. CREDIT: STEPHANIE ABRAMOWICZ Body sizes of marine amniotes span six orders of magnitude, yet the factors that governed the evolution of this diversity are largely unknown. High primary production of modern oceans is considered a prerequisite for the emergence of cetacean giants, but that condition cannot explain gigantism in Triassic ichthyosaurs. We describe the new giant ichthyosaur Cymbospondylus youngorum sp. nov. with a 2-meter-long skull from the Middle Triassic Fossil Hill Fauna of Nevada, USA, underscoring rapid size evolution despite the absence of many modern primary producers. Surprisingly, the Fossil Hill Fauna rivaled the composition of modern marine mammal faunas in terms of size range, and energy-flux models suggest that Middle Triassic marine food webs were able to support several large-bodied ichthyosaurs at high trophic levels, shortly after ichthyosaur origins.", "keyphrases": ["large body size", "ichthyosaur", "cetacean", "emergence", "marine food webs"]}
{"id": "10.1002/spp2.1351", "title": "Nasal compartmentalization in Kogiidae (Cetacea, Physeteroidea): insights from a new late Miocene dwarf sperm whale from the Pisco Formation", "abstract": "Facial compartmentalization in the skull of extant pygmy whales (Kogiidae) is a unique feature among cetaceans that allows for the housing of a wide array of organs responsible for echolocation. Recent fossil findings indicate a remarkable disparity of the facial bone organization in Miocene kogiids, but the significance of such a rearrangement for the evolution of the clade has been barely explored. Here we describe Kogia danomurai sp. nov., a late Miocene (c.\u20095.8\u2009Ma) taxon from the Pisco Formation (Peru), based on a partially preserved skull with a new facial bone pattern. Phylogenetic analysis recovers K.\u2009danomurai as the most basal representative of the extant genus Kogia, displaying a combination of derived (incipiently developed and excavated sagittal facial crest) and plesiomorphic features (high position of the temporal fossa, and antorbital notch not transformed into a narrow slit). Furthermore, when compared with the extant Kogia, the facial patterning found in K.\u2009danomurai indicates differential development among the facial organs, implying different capabilities of sound production relative to extant Kogia spp. Different facial bone patterns are particularly notable within the multi\u2010species kogiid assemblage of the Pisco Formation, which suggests causal connections between different patterns and feeding ecologies (e.g. nekton piscivory and benthic foraging). At c.\u20095.8\u2009Ma, K.\u2009danomurai was part of a cetacean community composed of clades typical of the late Miocene, and of other early representatives of extant taxa, a mixture probably representing an initial shift of the coastal faunas toward the ecosystem dynamics of the present\u2010day south\u2010eastern Pacific.", "keyphrases": ["compartmentalization", "kogiidae", "pisco formation", "organ", "facial crest"]}
{"id": "paleo.002997", "title": "The distribution of dental features in non-avian theropod dinosaurs: Taxonomic potential, degree of homoplasy, and major evolutionary trends", "abstract": "Isolated theropod teeth are some of the most common fossils in the dinosaur fossil record and are continually reported in the literature. Recently developed quantitative methods have improved our ability to test the affinities of isolated teeth in a repeatable framework. But in most studies, teeth are diagnosed on qualitative characters. This can be problematic because the distribution of theropod dental characters is still poorly documented, and often restricted to one lineage. To help in the identification of isolated theropod teeth, and to more rigorously evaluate their taxonomic and phylogenetic potential, we evaluated dental features in two ways. We first analyzed the distribution of 34 qualitative dental characters in a broad sample of taxa. Functional properties for each dental feature were included to assess how functional similarity generates homoplasy. We then compiled a quantitative data matrix of 145 dental characters for 97 saurischian taxa. The latter was used to assess the degree of homoplasy of qualitative dental characters, address longstanding questions on the taxonomic and biostratigraphic value of theropod teeth, and explore the major evolutionary trends in the theropod dentition. In smaller phylogenetic datasets for Theropoda, dental characters exhibit higher levels of homoplasy than non-dental characters, yet they still provide useful grouping information and optimize as local synapomorphies of smaller clades. In broader phylogenetic datasets, the degree of homoplasy displayed by dental and non-dental characters is not significantly different. Dental features on crown ornamentations, enamel texture and tooth microstructure have significantly less homoplasy than other dental features and can be used to identify many theropod taxa to \u2018family\u2019 or \u2019sub-family\u2019 level, and some taxa to genus or species. These features should, therefore, be a priority for investigations seeking to classify isolated teeth. Our observations improve the taxonomic utility of theropod teeth and in some cases can help make isolated teeth useful as biostratigraphic markers. This proposed list of dental features in theropods should, therefore, facilitate future studies on the systematic paleontology of isolated teeth. HENDRICKX ET AL.: DENTAL FEATURES IN THEROPODS 2 Christophe Hendrickx. Evolutionary Studies Institute, University of the Witwatersrand, South Africa. currently: Unidad Ejecutora Lillo, CONICET-Fundaci\u00f3n Miguel Lillo, Miguel Lillo 251, San Miguel de Tucum\u00e1n 4000, Tucum\u00e1n, Argentina. christophendrickx@gmail.com Oct\u00e1vio Mateus. Museu da Lourinh\u00e3, 9 Rua Jo\u00e3o Luis de Moura, 2530-158, Lourinh\u00e3, Portugal; Universidade Nova de Lisboa, Departamento de Ci\u00eancias da Terra, Faculdade de Ci\u00eancias e Tecnologia, Quinta da Torre, 2829-516, Caparica, Portugal. omateus@fct.unl.pt Ricardo Ara\u00fajo. Museu da Lourinh\u00e3, 9 Rua Jo\u00e3o Luis de Moura, 2530-158, Lourinh\u00e3, Portugal; Huffington Department of Earth Sciences, Southern Methodist University, PO Box 750395, 75275-0395, Dallas, Texas, USA; Instituto de Plasmas e Fus\u00e3o Nuclear, Instituto Superior T\u00e9cnico, Universidade de Lisboa, Portugal; Museum f\u00fcr Naturkunde, Berlin, Germany. rmaraujo@smu.edu Jonah Choiniere. Evolutionary Studies Institute, University of the Witwatersrand, South Africa. jonah.choiniere@wits.ac.za", "keyphrases": ["dental feature", "homoplasy", "major evolutionary trend", "isolated tooth"]}
{"id": "paleo.002885", "title": "Ontogeny and the fossil record: what, if anything, is an adult dinosaur?", "abstract": "Identification of the ontogenetic status of an extinct organism is complex, and yet this underpins major areas of research, from taxonomy and systematics to ecology and evolution. In the case of the non-avialan dinosaurs, at least some were reproductively mature before they were skeletally mature, and a lack of consensus on how to define an \u2018adult\u2019 animal causes problems for even basic scientific investigations. Here we review the current methods available to determine the age of non-avialan dinosaurs, discuss the definitions of different ontogenetic stages, and summarize the implications of these disparate definitions for dinosaur palaeontology. Most critically, a growing body of evidence suggests that many dinosaurs that would be considered \u2018adults\u2019 in a modern-day field study are considered \u2018juveniles\u2019 or \u2018subadults\u2019 in palaeontological contexts.", "keyphrases": ["juvenile", "subadult", "ontogeny"]}
{"id": "paleo.011071", "title": "Structural Extremes in a Cretaceous Dinosaur", "abstract": "Fossils of the Early Cretaceous dinosaur, Nigersaurus taqueti, document for the first time the cranial anatomy of a rebbachisaurid sauropod. Its extreme adaptations for herbivory at ground-level challenge current hypotheses regarding feeding function and feeding strategy among diplodocoids, the larger clade of sauropods that includes Nigersaurus. We used high resolution computed tomography, stereolithography, and standard molding and casting techniques to reassemble the extremely fragile skull. Computed tomography also allowed us to render the first endocast for a sauropod preserving portions of the olfactory bulbs, cerebrum and inner ear, the latter permitting us to establish habitual head posture. To elucidate evidence of tooth wear and tooth replacement rate, we used photographic-casting techniques and crown thin sections, respectively. To reconstruct its 9-meter postcranial skeleton, we combined and size-adjusted multiple partial skeletons. Finally, we used maximum parsimony algorithms on character data to obtain the best estimate of phylogenetic relationships among diplodocoid sauropods. Nigersaurus taqueti shows extreme adaptations for a dinosaurian herbivore including a skull of extremely light construction, tooth batteries located at the distal end of the jaws, tooth replacement as fast as one per month, an expanded muzzle that faces directly toward the ground, and hollow presacral vertebral centra with more air sac space than bone by volume. A cranial endocast provides the first reasonably complete view of a sauropod brain including its small olfactory bulbs and cerebrum. Skeletal and dental evidence suggests that Nigersaurus was a ground-level herbivore that gathered and sliced relatively soft vegetation, the culmination of a low-browsing feeding strategy first established among diplodocoids during the Jurassic.", "keyphrases": ["cretaceous dinosaur", "nigersaurus", "rebbachisaurid", "sauropod", "diplodocoid"]}
{"id": "paleo.011785", "title": "Heterodonty and ontogenetic shift dynamics in the dentition of the tiger shark Galeocerdo cuvier (Chondrichthyes, Galeocerdidae)", "abstract": "The lifelong tooth replacement in elasmobranch fishes (sharks, rays and skates) has led to the assemblage of a great number of teeth from fossil and extant species, rendering tooth morphology an important character for taxonomic descriptions, analysing phylogenetic interrelationships and deciphering their evolutionary history (e.g. origination, divergence, extinction). Heterodonty (exhibition of different tooth morphologies) occurs in most elasmobranch species and has proven to be one of the main challenges for these analyses. Although numerous shark species are discovered and described every year, detailed descriptions of tooth morphologies and heterodonty patterns are lacking or are only insufficiently known for most species. Here, we use landmark\u2010based 2D geometric morphometrics on teeth of the tiger shark Galeocerdo cuvier to analyse and describe dental heterodonties among four different ontogenetic stages ranging from embryo to adult. Our results reveal rather gradual and subtle ontogenetic shape changes, mostly characterized by increasing size and complexity of the teeth. We furthermore provide the first comprehensive description of embryonic dental morphologies in tiger sharks. Also, tooth shapes of tiger sharks in different ontogenetic stages are re\u2010assessed and depicted in detail. Finally, multiple cases of tooth file reversal are described. This study, therefore, contributes to our knowledge of dental traits across ontogeny in the extant tiger shark G. cuvier and provides a baseline for further morphological and genetic studies on the dental variation in sharks. Therefore, it has the potential to assist elucidating the underlying developmental and evolutionary processes behind the vast dental diversity observed in elasmobranch fishes today and in deep time.", "keyphrases": ["ontogeny", "dental variation", "heterodonty"]}
{"id": "10.1111/j.1096-3642.2009.00480.x", "title": "Comparative ossification and development of the skull in palaeognathous birds (Aves: Palaeognathae)", "abstract": "Ratites and tinamous are a morphologically diverse group of flightless and weakly flighted birds. As one of the most basal clades of extant birds, they are frequently used as an outgroup for studies discussing character evolution within other avian orders. Their skeletal development is not well known in spite of their important phylogenetic position, and studies have historically been plagued with small sample sizes and limited anatomical and temporal scope. Here, I describe the ossification of the skull in the emu (Dromaius novaehollandiae), ostrich (Struthio camelus), greater rhea (Rhea americana), and elegant crested-tinamou (Eudromia elegans). Skeletal development is remarkably consistent within palaeognaths, in spite of large differences in absolute size and incubation period. Adult morphology appears to play a role in interordinal differences in the sequence and timing of ossification of certain bones. Neither the timing of cranial ossification events relative to stage nor the sequence of ossification events provides any evidence in support of a paedomorphic origin of the palaeognathous palate. This study provides an important first look at the timing and sequence of skull development in palaeognathous birds, providing data that can be compared to better-studied avian systems in order to polarize ontogenetic characters.\u00a0\u00a9 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 156, 184\u2013200.", "keyphrases": ["ossification", "skull", "palaeognathous bird"]}
{"id": "paleo.005656", "title": "Comparative limb proportions reveal differential locomotor morphofunctions of alligatoroids and crocodyloids", "abstract": "Although two major clades of crocodylians (Alligatoroidea and Crocodyloidea) were split during the Cretaceous period, relatively few morphological and functional differences between them have been known. In addition, interaction of multiple morphofunctional systems that differentiated their ecology has barely been assessed. In this study, we examined the limb proportions of crocodylians to infer the differences of locomotor functions between alligatoroids and crocodyloids, and tested the correlation of locomotor and feeding morphofunctions. Our analyses revealed crocodyloids including Gavialis have longer stylopodia (humerus and femur) than alligatoroids, indicating that two groups may differ in locomotor functions. Fossil evidence suggested that alligatoroids have retained short stylopodia since the early stage of their evolution. Furthermore, rostral shape, an indicator of trophic function, is correlated with limb proportions, where slender-snouted piscivorous taxa have relatively long stylopodia and short overall limbs. In combination, trophic and locomotor functions might differently delimit the ecological opportunity of alligatoroids and crocodyloids in the evolution of crocodylians.", "keyphrases": ["limb proportion", "alligatoroid", "crocodyloid"]}
{"id": "paleo.007190", "title": "Medullary bone-like tissue in the mandibular symphyses of a pterosaur suggests non-reproductive significance", "abstract": "Medullary bone is a special bone tissue forming on the endosteal surface of the medullary cavity in the bones of female birds prior to and during egg-laying to serve as a calcium reservoir for building the hard eggshell. It has also been identified in non-avian dinosaurs, where its presence is considered as a reliable indicator of a sexually mature female. Here, we reveal that multiple mandibular symphyses of the azhdarchid pterosaur Bakonydraco galaczi possess a special bone tissue that shows all microanatomical, histological, and developmental characteristics of medullary bone, despite its unusual location. Its frequent occurrence in the sample renders a pathologic origin unlikely. Our findings as well as the extremely thin-shelled eggs of pterosaurs suggest that this medullary bone-like tissue probably had a non-reproductive role in these animals. Although the non-reproductive significance and the anatomical location of this medullary bone-like tissue in Bakonydraco suggest independent evolutionary appearance from dinosaurian medullary bone, a common origin and later diverging function and physiological regulation is an equally viable phylogenetic hypothesis.\nedullary bone is a non-structural type of bone tissue that, under natural conditions, develops in the haematopoietic medullary cavities of bones of female birds induced by oestrogenic and androgenic hormones during the egg-laying cycle 1,2 . Under experimental conditions, administration of these hormones to male birds also results in medullary bone formation [3] [4] [5] . Growing from the endosteal layers inwards to the medullar cavity, and mostly being composed of woven bone 6 , medullary bone has no mechanical function but serves as a calcium storage that can be quickly mobilized during the calcification of the hard-shelled eggs of birds [6] [7] [8] [9] . According to the phases of the egg-laying cycle, medullary bone can be characterized by rapid formation in the period of maturing follicles, and subsequent rapid destruction during the calcification of the eggshell 10-12 . This fast formation-resorption cycle of medullary bone corresponds well with its microanatomy as well as histology: (i) it has large surface areas due to its highly porous, vascularized nature; (ii) its trabeculae are composed of woven bone 6 ; (iii) the number and activity level of osteoclasts is considerably higher in medullary bone than in cortical bone 13 . The composition of medullary bone is similar to that of cortical and cancellous trabecular bone; however, the proportional amount of components are different with medullary bone being more calcified, having higher apatite to collagen ratio, and containing more non-collagenous proteins, proteoglycans and carbohydrates in the matrix 7, 12, 14, 15 .\nThis bone tissue type was first described in pigeons 16 , and later in some other species of extant birds, among others in domestic fowl, Japanese quail, duck and ostrich 3, 10, 11, [17] [18] [19] [20] [21] . The amount, microanatomy and distribution of medullary bone can be different in different species of birds as well as in different phases of the reproductive cycle 1, 11, 17, 21, 22 . Apart from the controversial results on mice forming medullary bone-like tissues in response to unnaturally high oestrogen doses 23, 24 , medullary bone has not been reported in any extant non-avian amniotes 25, 26 . Recently, with the discovery of medullary bone in different non-avian dinosaurs, the occurrence of medullary bone has proven to be phylogenetically more widespread and is considered as further evidence for the close relationship between birds and theropod dinosaurs 21, [27] [28] [29] . Apart from dinosaurs, there has been only one report on the presence of an extensive, endosteally derived bone structure in a single femur of the Early Cretaceous pterosaur Pterodaustro that was tentatively interpreted as medullary bone 30 . Since it has been found in theropod 21, 27, 29 as well as in ornithopod 27,28 dinosaurs but not in extant alligators 31, 32 , medullary bone has been suggested to have first appeared in the ornithodiran lineage of archosaurs after its divergence from crocodilians 27, 32 .", "keyphrases": ["non-reproductive significance", "medullary bone-like tissue", "mandibular symphysis"]}
{"id": "paleo.008608", "title": "Diversification of insects since the Devonian: a new approach based on morphological disparity of mouthparts", "abstract": "The majority of the analyses of the evolutionary history of the megadiverse class Insecta are based on the documented taxonomic palaeobiodiversity. A different approach, poorly investigated, is to focus on morphological disparity, linked to changes in the organisms\u2019 functioning. Here we establish a hierarchy of the great geological epochs based on a new method using Wagner parsimony and a \u2018presence/absence of a morphological type of mouthpart of Hexapoda\u2019 dataset. We showed the absence of major rupture in the evolution of the mouthparts, but six epochs during which numerous innovations and few extinctions happened, i.e., Late Carboniferous, Middle and Late Triassic, \u2018Callovian-Oxfordian\u2019, \u2018Early\u2019 Cretaceous, and \u2018Albian-Cenomanian\u2019. The three crises Permian-Triassic, Triassic-Jurassic, and Cretaceous-Cenozoic had no strong, visible impact on mouthparts types. We particularly emphasize the origination of mouthparts linked to nectarivory during the Cretaceous Terrestrial Revolution. We also underline the origination of mouthparts linked to phytophagy during the Middle and the Late Triassic, correlated to the diversification of the gymnosperms, especially in relation to the complex \u2018flowers\u2019 producing nectar of the Bennettitales and Gnetales.", "keyphrases": ["insect", "morphological disparity", "mouthpart"]}
{"id": "10.1017/S0094837300004978", "title": "Late Wisconsin mammalian faunas and environmental gradients of the eastern United States", "abstract": "Small mammal species distribution, density, and composition of modern and Pleistocene faunas from the eastern United States provide information about environmental gradients. Higher summer temperatures and less effective moisture along a transect from the northeast to the southwest can be correlated with the distribution of small mammals as well as decreases in the total number of shrew and vole species. Relative frequencies of \u201cboreal\u201d, \u201cdeciduous\u201d, and \u201csteppe\u201d species are more equal in late Wisconsin than modern faunas which are predominantly composed of only one group. A higher vole species density is prevalent in each late Wisconsin fauna and eleven of twelve of these faunas have a higher shrew species density than the corresponding modern fauna. Many shrew and vole species that are today endemic to the boreal provinces were cosmopolitan during the late Wisconsin. Moderate environmental gradients of the equable late Wisconsin climates allowed integration of boreal species with resident species in the south.", "keyphrases": ["environmental gradient", "eastern united states", "late wisconsin"]}
{"id": "10.1111/j.1096-3642.2009.00614.x", "title": "Cranial anatomy of Paleocene and Eocene Labidolemur kayi (Mammalia: Apatotheria), and the relationships of the Apatemyidae to other mammals", "abstract": "The relationships of the extinct mammalian family Apatemyidae are poorly resolved. Three new, well-preserved crania of Labidolemur kayi from the late Paleocene (Clarkforkian) and early Eocene (Wasatchian) of North America are described in part using ultra high resolution X-ray computed tomography data. These specimens permit the first descriptions of critical components of apatemyid cranial anatomy, such as the composition of the tympanic roof, and the pathways of the internal carotid artery and facial nerve. Results from cladistic analyses of morphological data for known apatemyids and a broad sample of eutherians suggest that apatemyids are basal members of Euarchontoglires, with weak support for a sister-group relationship with Glires. Although apatemyids are sufficiently different from other mammals to be placed in their own order, Apatotheria, it is clear that they are likely to be important for understanding primitive characteristics of Euarchontoglires and Boreoeutheria. \n \n \n \n\u00a9 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160, 773\u2013825.", "keyphrases": ["paleocene", "other mammal", "cranial anatomy"]}
{"id": "10.1111/2041-210X.12081", "title": "A stochastic rate\u2010calibrated method for time\u2010scaling phylogenies of fossil taxa", "abstract": "Applying phylogeny\u2010based analyses of trait evolution and diversification in the fossil record generally involves transforming an unscaled cladogram into a phylogeny scaled to geologic time. Current methods produce single time\u2010scaled phylogenies with no indication of the uncertainty in the temporal relationships and, under some methods, artificial zero\u2010length branches. Here, I present a stochastic algorithm for time\u2010scaling phylogenies of fossil taxa by randomly sampling node ages from a constrained distribution, with the ultimate goal of producing large samples of time\u2010scaled phylogenies for a given data set as the basis for phylogeny\u2010based analyses. I describe how this stochastic approach can be extended to consider potential ancestral relationships and resolve polytomies. The stochastic selection of node ages in this algorithm is weighted by the probability density of the total inferable unobserved evolutionary history at single divergence events in a tree, a distribution dependent on rates of branching, extinction and sampling in the fossil record. The combined time\u2010scaling method must be calibrated with explicit estimates of three rates: branching, extinction and sampling, and thus is named the cal3 time\u2010scaling method, included in the r library paleotree. I test the time\u2010scaling capabilities of the cal3 and older time\u2010scaling methods in simulations. cal3 produces samples of time\u2010scaled trees that better bracket the uncertainty in the true node ages than existing time\u2010scaling methods. This is true even in simulations under a \u2018terminal\u2010taxon\u2019 model of differentiation that violates many of the assumptions of the cal3 method. The cal3 method provides a new approach for time\u2010scaling palaeontological cladograms, calibrated to estimated sampling and diversification rates, allowing for better estimates of uncertainty in the phylogenetic time\u2010scaling. The cal3 method is robust to relaxation of at least some model assumptions. Additional work is needed to analyse the impact of time\u2010scaling approaches on macroevolutionary analyses and to integrate time\u2010scaling with phylogenetic inference.", "keyphrases": ["fossil taxa", "sampling", "tree", "cal3", "occurrence data"]}
{"id": "10.1073/pnas.0608443103", "title": "Early modern humans from the Pe\u015ftera Muierii, Baia de Fier, Romania", "abstract": "The early modern human remains from the Pe\u015ftera Muierii, Romania have been directly dated to \u224830,000 radiocarbon years before present (\u224830 ka 14C BP) (\u224835 ka cal BP) (\u201ccalendrical\u201d age; based on CalPal 2005) and augment a small sample of securely dated, European, pre-28 ka 14C BP (\u224832.5 ka cal BP) modern human remains. The Muierii fossils exhibit a suite of derived modern human features, including reduced maxillae with pronounced canine fossae, a narrow nasal aperture, small superciliary arches, an arched parietal curve, zygomatic arch above the auditory porous, laterally bulbous mastoid processes, narrow mandibular corpus, reduced anterior dentition, ventral-to-bisulcate scapular axillary border, and planoconcave tibial and fibular diaphyseal surfaces. However, these traits co-occur with contextually archaic and/or Neandertal features, including a moderately low frontal arc, a large occipital bun, a high coronoid process and asymmetrical mandibular notch, a more medial mandibular notch crest to condylar position, and a narrow scapular glenoid fossa. As with other European early modern humans, the mosaic of modern human and archaic/Neandertal features, relative to their potential Middle Paleolithic ancestral populations, indicates considerable Neandertal/modern human admixture. Moreover, the narrow scapular glenoid fossa suggests habitual movements at variance with the associated projectile technology. The reproductive and scapulohumeral functional inferences emphasize the subtle natures of behavioral contrasts between Neandertals and these early modern Europeans.", "keyphrases": ["pe\u015ftera muierii", "romania", "early modern human"]}
{"id": "paleo.010948", "title": "Multiple S-isotopic evidence for episodic shoaling of anoxic water during Late Permian mass extinction", "abstract": "Global fossil data show that profound biodiversity loss preceded the final catastrophe that killed nearly 90% marine species on a global scale at the end of the Permian. Many hypotheses have been proposed to explain this extinction and yet still remain greatly debated. Here, we report analyses of all four sulphur isotopes (32S, 33S, 34S and 36S) for pyrites in sedimentary rocks from the Meishan section in South China. We observe a sulphur isotope signal (negative \u03b434S with negative \u039433S) that may have resulted from limitation of sulphate supply, which may be linked to a near shutdown of bioturbation during shoaling of anoxic water. These results indicate that episodic shoaling of anoxic water may have contributed to the profound biodiversity crisis before the final catastrophe. Our data suggest a prolonged deterioration of oceanic environments during the Late Permian mass extinction.", "keyphrases": ["episodic shoaling", "anoxic water", "permian mass extinction"]}
{"id": "10.1080/03115510802618219", "title": "The oldest South Australian cowries (Gastropoda: Cypraeidae) from the Paleogene of the St Vincent Basin", "abstract": "Yates, A.M., March, 2009. The oldest South Australian cowries (Gastropoda: Cypraeidae) from the Paleogene of the St Vincent Basin. Alcheringa 33, 23\u201331. ISSN 0311-5518. Two occurrences of cowries in the Paleogene of the St Vincent Basin are described. Two cypraeid internal moulds from the late Eocene (Aldingan) Blanche Point Formation comprise one such occurrence. These are among the oldest recorded Australian cypraeids. They bear some resemblance to the genera Zoila and Umbilia but insufficient details are preserved for accurate identification. The second occurrence consists of a series of internal and external moulds from the early Oligocene of the Port Willunga Formation. These represent a new species of the endemic subgenus Lyncina (Austrocypraea), here described as L. (A.) onkastoma. This species is the oldest known member of the subgenus but its apparently derived characteristics indicate that the subgenus had already diversified by this time.", "keyphrases": ["south australian cowrie", "cypraeidae", "paleogene"]}
{"id": "paleo.006264", "title": "JURASSIC PALAEONTINIDAE FROM CHINA AND THE HIGHER SYSTEMATICS OF PALAEONTINOIDEA (INSECTA: HEMIPTERA: CICADOMORPHA)", "abstract": "Abstract:\u2002 Genera of Palaeontinidae (Insecta, Hemiptera: Cicadomorpha) are reviewed based on some newly\u2010discovered material. An updated list of palaeontinid genera is provided. The genus Palaeontinopsis Martynov is assigned to Palaeontinidae incertae sedis. A new genus and species, Ningchengia aspera gen. et sp. nov., is described based on forewings and hindwings from the Middle Jurassic of Daohugou, China. Fletcheriana colorata Wang, Zhang and Fang and F. minuta Wang, Zhang and Fang are transferred to Suljuktocossus and Ningchengia respectively, resulting in Suljuktocossus coloratus comb. nov. and Ningchengia minuta comb. nov. Papilioncossus Wang, Ren and Shih, 2007 syn. nov. is considered to be a junior synonym of Eoiocossus Wang and Zhang, 2006 and Quadraticossus Wang and Ren 2007 syn. nov. is a junior synonym of Sinopalaeocossus Hong, 1983 . The genus Fletcheriana is believed to represent a transition between Dunstaniidae and Palaeontinidae. This result is consistent with the previous view that Dunstaniidae is ancestral to Palaeontinidae. Furthermore, Suljuktocossus is a transitional genus between Fletcheriana and Cretaceous palaeontinids. The fusion of veins RP and M1 in the palaeontinid hindwings implies a change of the mechanism of flight and an improvement in flight ability. The presence of a reduced costal area and the rigid basal leading edge of the palaeontinid forewings suggest gain of lift.", "keyphrases": ["insecta", "hemiptera", "cicadomorpha"]}
{"id": "10.2110/palo.2005.p05-089r", "title": "OXYGEN ISOTOPIC COMPOSITION OF BIOGENIC PHOSPHATE AND THE TEMPERATURE OF EARLY ORDOVICIAN SEAWATER", "abstract": "Abstract Stable isotopic values were measured on micrite, sparry calcite, dolomite, inarticulated brachiopods, and conodonts from the Lange Ranch section (central Texas) of the Lower Ordovician Tanyard Formation. The section spans the upper Cordylodus angulatus Zone through the lower Rossodus manitouensis Zone. An \u223c2\u2030 negative \u03b413C shift from >0\u2030 to <\u22121.5\u2030VPDB through the section suggests the lower third of the Rossodus manitouensis Zone was sampled. Consistent with previous studies, the \u03b418O values of carbonates are low, ranging from \u22123.3\u2030 to \u22128.1\u2030VPDB. Phosphate \u03b418O values range from 15.4\u2030 to 17.1\u2030VSMOW. Paleotemperature estimates calculated from micrite \u03b418O values assuming an ice-free seawater \u03b418O value of \u22121\u2030VSMOW indicate Early Ordovician tropical seawater temperatures averaged 42\u00b0C, whereas \u03b418O values of co-occurring biogenic phosphate assuming the same seawater value yield paleotemperature estimates averaging 37\u00b0C. The phosphate values are interpreted as less affected by diagenesis than carbonate values and suggest Early Ordovician tropical paleotemperatures were not more than 10\u00b0C warmer or the oxygen isotopic composition of Early Ordovician hydrosphere was not more than 2\u2030 lower than present.", "keyphrases": ["isotopic composition", "biogenic phosphate", "oxygen"]}
{"id": "paleo.002237", "title": "New data on the Oxyaenidae from the Early Eocene of Europe; biostratigraphic, paleobiogeographic and paleoecologic implications", "abstract": "The locality of Le Quesnoy (France; MP7) has yielded a diversified mammal fauna including especially large mammals. Oxyaenidae are well documented with two species identified: Oxyaena woutersi and Palaeonictis gigantea. The Le Quesnoy material illustrates almost the entire dentition of these species. Its study supports the generic attribution of Oxyaena woutersi. Its M 2 is more secant than in the primitive Dipsalidictis, but the M 1 appears to be slightly less secant than in the earliest species of Oxyaena. Oxyaena woutersi is a morphological intermediate between the Clarkforkian-Wasatchian Dipsalidictis and the Wasatchian Oxyaena. The M 2 of Palaeonictis gigantea is compared to the sole known molar of Dormaalodon woutersi. Dormaalodon is here demonstrated to be a junior synonym of Palaeonictis. Several postcranial elements of Oxyaena woutersi and Palaeonictis gigantea are described: they are the first described for European oxyaenids. The oxyaenid species from Le Quesnoy and Dormaal show a close affinity and support an age very close to MP7 for Le Quesnoy. The Le Quesnoy oxyaenids are morphologically close to the North American species of Wa0, which supports correlation with this level. We revised the European Oxyaenidae previously described from younger localities. Fossils from Meudon, Sinceny and Abbey Wood (MP8+9) are referred to Oxyaena sp. A North American origin of the Oxyaenidae is confirmed. Our study supports a single dispersal event of oxyaenids from North America to Europe followed by a short endemic local evolution. Oxyaenidae rapidly disappeared from Europe. This disappearance could support the distinction between the MP7 and MP8+9 reference levels.", "keyphrases": ["oxyaenidae", "early eocene", "europe", "dormaal", "hyaenodont"]}
{"id": "paleo.008597", "title": "Ontogenetic Tooth Reduction in Stenopterygius quadriscissus (Reptilia: Ichthyosauria): Negative Allometry, Changes in Growth Rate, and Early Senescence of the Dental Lamina", "abstract": "We explore the functional, developmental, and evolutionary processes which are argued to produce tooth reduction in the extinct marine reptile Stenopterygius quadriscissus (Reptilia: Ichthyosauria). We analyze the relationship between mandible growth and tooth size, shape, and count, to establish an ontogenetic trend. The pattern in S. quadriscissus is consistent with hypotheses of tooth size reduction by neutral selection, and this unusual morphology (a functionally edentulous rostrum) was produced by a series of different evolutionary developmental changes that are known for other taxa showing tooth reduction and loss. Specifically, this species evolved functional edentulism by evolutionary changes in the growth allometry of the dentition and by altering growth rates through ontogeny. This observation supports previous hypotheses that S. quadriscissus underwent ontogenetic tooth reduction. Tooth reduction in S. quadriscissus may be caused by unique selective pressures resulting from prey choice and feeding behavior, expanding our current understanding of the mechanisms producing tooth reduction.", "keyphrases": ["reptilia", "growth rate", "ontogenetic tooth reduction"]}
{"id": "10.1080/08912963.2018.1539971", "title": "New chondrichthyans characterised by cladodont-like tooth morphologies from the Early Cretaceous of Austria, with remarks on the microstructural diversity of enameloid", "abstract": "ABSTRACT Cladodontomorphii represents an archaic clade of chondrichthyan fishes characterised by distinct tooth morphologies referred to as the cladodont type. This group of cartilaginous fishes first occurred during the early Palaeozoic Era as revealed from the fossil record and were long thought to have gone extinct at the Permian-Triassic mass extinction event. However, a recently reported chondrichthyan tooth assemblage from the Early Cretaceous of France suggests that cladodontomorphs might have survived the catastrophic events at the Permian-Triassic boundary, probably by occupying deep-sea refuge environments. Here, we describe two new chondrichthyan genera based on isolated teeth recovered from Valanginian (Early Cretaceous) deep-water deposits of Austria, including a total of three new species tentatively assigned to the cladodontomorph families Falcatidae (Cretacladoides ogiveformis gen. et sp. nov. and C. noricum sp. nov.) and Ctenacanthidae (Natarapax trivortex gen. et sp. nov.). In addition, an enameloid microstructure analysis had led to the identification of a distinct multilayered enameloid including a parallel-, tangled-, and radial-bundled enameloid, whose phylogenetic distribution within Chondrichthyes is here discussed in detail, leading to the conclusion that the herein described cladodont-like taxa, together with those reported from the French Early Cretaceous might be closely related to ancient Palaeozoic taxa. The ZooBank electronic publication LSID is: urn:lsid:zoobank.org:pub:C06FD718-F54F-4C57-A45E-8C0D7CC8EB83", "keyphrases": ["tooth morphology", "early cretaceous", "enameloid"]}
{"id": "paleo.002609", "title": "Ecological opportunity and the rise and fall of crocodylomorph evolutionary innovation", "abstract": "Understanding the origin, expansion and loss of biodiversity is fundamental to evolutionary biology. The approximately 26 living species of crocodylomorphs (crocodiles, caimans, alligators and gharials) represent just a snapshot of the group's rich 230-million-year history, whereas the fossil record reveals a hidden past of great diversity and innovation, including ocean and land-dwelling forms, herbivores, omnivores and apex predators. In this macroevolutionary study of skull and jaw shape disparity, we show that crocodylomorph ecomorphological variation peaked in the Cretaceous, before declining in the Cenozoic, and the rise and fall of disparity was associated with great heterogeneity in evolutionary rates. Taxonomically diverse and ecologically divergent Mesozoic crocodylomorphs, like marine thalattosuchians and terrestrial notosuchians, rapidly evolved novel skull and jaw morphologies to fill specialized adaptive zones. Disparity in semi-aquatic predatory crocodylians, the only living crocodylomorph representatives, accumulated steadily, and they evolved more slowly for most of the last 80 million years, but despite their conservatism there is no evidence for long-term evolutionary stagnation. These complex evolutionary dynamics reflect ecological opportunities, that were readily exploited by some Mesozoic crocodylomorphs but more limited in Cenozoic crocodylians.", "keyphrases": ["crocodylomorph", "innovation", "ecological opportunity"]}
{"id": "paleo.003671", "title": "New subgenus and three new species of soldier beetles from the Eocene of Baltic amber", "abstract": "One fossil subgenus and three fossil species of soldier beetles: Libertimalthodes subg. nov., Cantharis (Cantharis) dougi sp. nov., Malthodes (Libertimalthodes) elytratus sp. nov. and Malthodes (Malthodes) nublar sp. nov., are described from Eocene Baltic amber. The deposit appears to be comparatively rich in inclusions of Cantharidae. The new subgenus differs from the nominotypical subgenus in possessing elytra that are elongated and covering the last abdominal urites, a huge aedeagus and the last abdominal sternite that is wide and little modified. Furthermore, the new species has an aedeagus that is almost completely extruded, which is a rare feature to find in fossils of soldier beetles. Malthodes nublar sp. nov. is characterized by short elytra and has a different shape of the terminalia, while Cantharis dougi sp. nov. has a different pronotal shape than in known fossil species. Malthodes aphidiphagus Fanti and Michalski, 2018, is transferred from the nominotypical subgenus Malthodes to the new subgenus Libertimalthodes. Janusz Kupryjanowicz. Professor Andrzej Myrcha University Center of Nature, University of Bia\u0142ystok, ul. Cio\u0142kowskiego 1J, 15-245 Bia\u0142ystok, Poland. kuprzool@uwb.edu.pl Fabrizio Fanti. Via del Tamburino 69, I-53040 Piazze (SI), Italy. fantifab@alice.it", "keyphrases": ["subgenus", "soldier beetle", "baltic amber", "fossil specie", "aedeagus"]}
{"id": "10.1080/14772019.2014.911212", "title": "A new European Late Jurassic pleurosternid (Testudines, Paracryptodira) and a new hypothesis of paracryptodiran phylogeny", "abstract": "Paracryptodira was an abundant and diverse group of freshwater turtles, recognized both in North America and Europe. Its known record spans the Middle Jurassic to the Eocene. The internal phylogenetic relationships of one of its clades, Baenidae, are relatively well known. However, information on the relationships amongst the non-baenid members is very limited and, so far, poorly justified. A new study on the phylogenetic relationships amongst Paracryptodira is undertaken here through the revision of previously described taxa, the incorporation of information on taxa recently discovered or revised, and the study of new material. In addition, a new taxon from the Late Jurassic of Europe is described: Riodevemys inumbragigas gen. et sp. nov. It is identified as a member of Pleurosternidae, constituting the first generic and specific attribution of a pleurosternid in the Spanish fossil record. Pleurosternidae is obtained here as a robust node whose composition differs from previous proposals. The relationships amongst representatives are analysed. In addition, we define a new clade, Compsemydidae, identified as the sister group of Baenoidea (Baenidae + Pleurosternidae). The new phylogenetic proposal, and its analysis in view of stratigraphical distributions, shows that Baenidae was a clade of turtles only known in the Cretaceous and Palaeogene of the North American record but that Pleurosternidae and Compsemydidae were distributed both in North America and Europe. The temporal distribution of Pleurosternidae is restricted here, refuting some putatively older and younger occurrences. This new hypothesis restricts its known distribution to the Late Jurassic of North America and the Late Jurassic and the first part of the Early Cretaceous of Europe. The new clade Compsemydidae is recognized in the Late Cretaceous and Palaeocene of North America and in younger levels of the European Palaeocene. http://zoobank.org/urn:lsid:zoobank.org:pub:1BA05241-4DAE-490F-B454-4CF32BCA4B42", "keyphrases": ["paracryptodira", "new hypothesis", "baenoidea", "phylogenetic analysis"]}
{"id": "paleo.001303", "title": "Faunal response to sea\u2010level and climate change in a short\u2010lived seaway: Jurassic of the Western Interior, USA", "abstract": "Understanding how regional ecosystems respond to sea\u2010level and environmental perturbations is a main challenge in palaeoecology. Here we use quantitative abundance estimates, integrated within a sequence stratigraphic and environmental framework, to reconstruct benthic community changes through the 13 myr history of the Jurassic Sundance Seaway in the western United States. Sundance Seaway communities are notable for their low richness and high dominance relative to most areas globally in the Jurassic, and this probably reflects steep temperature and salinity gradients along the 2000 km length of the Seaway that hindered colonization of species from the open ocean. Ordination of samples shows a main turnover event at the Middle\u2013Upper Jurassic transition, which coincided with a shift from carbonate to siliciclastic depositional systems in the Seaway, probably initiated by northward drift from subtropical latitudes to more humid temperate latitudes, and possibly global cooling. Turnover was not uniform across the onshore\u2013offshore gradient, but was higher in offshore environments. The higher resilience of onshore communities to third\u2010order sea\u2010level fluctuations and to the change from a carbonate to a siliciclastic system was driven by a few abundant eurytopic species that persisted from the opening to the closing of the Seaway. Lower stability in offshore facies was instead controlled by the presence of more volatile stenotopic species. Such increased onshore stability in community composition contrasts with the well\u2010documented onshore increase in taxonomic turnover rates, and this study underscores how ecological analyses of relative abundance may contrast with taxonomically based analyses. We also demonstrate the importance of a stratigraphic palaeobiological approach to reconstructing the links between environmental and faunal gradients, and how their evolution through time produces local stratigraphic changes in community composition.", "keyphrases": ["sea\u2010level", "seaway", "jurassic"]}
{"id": "10.3767/000651909X475941", "title": "Southeast Asia\u2019s changing palaeogeography", "abstract": "Geology provides the basis for understanding distributions of faunas and floras in Southeast Asia but only via a complex interplay of plate movements, palaeogeography, ocean circulation and climate. Southeast Asia grew incrementally by the addition of continental fragments, mainly rifted from Australia, and added to the margins of Sundaland as a result of subduction. Sundaland was an almost permanent land area from the beginning of the Mesozoic. The addition of the continental fragments of Southwest Borneo and later East Java\u2013West Sulawesi formed a much larger emergent land area by the Late Cretaceous that extended from Indochina to West Sulawesi. Subduction resumed at the Sundaland margin in the Eocene and this led to widespread rifting within Sundaland, and formed one of the most important barriers at its edge, the Makassar Straits. Australia began to collide with Southeast Asia about 25 million years ago, effectively closing the former deep ocean separating the two continents, and forming the region now known as Wallacea. Collision, volcanism, and subduction-related processes have led to rise of mountains but also formed new oceans within this complex region. Plate tectonic movements and collisions were intimately linked to changing topography, bathymetry and land/sea distributions which have in turn influenced oceanic circulation and climate. As the deep-water barrier between Australia and Southeast Asia was eliminated and mountains rose, deep marine basins also formed. Eustatic changes in sea level further contributed to a complex palaeogeography. The present gateway between the Pacific and Indian Oceans is the only low latitude oceanic passage between the world\u2019s oceans, and is an important influence on local and probably global climate. The gateway is likely to have been just as significant in the past. Understanding the geology, then palaeogeography, and then their oceanic and climatic consequences are vital steps on the way to interpreting present distributions of plants and animals.", "keyphrases": ["palaeogeography", "marine basin", "southeast asia"]}
{"id": "10.1002/rcm.6351", "title": "Site-specific deamidation of glutamine: a new marker of bone collagen deterioration.", "abstract": "RATIONALE\nNon-enzymatic deamidation accumulates in aging tissues in vivo and has been proposed to be potentially useful as a molecular clock. The process continues post mortem, and here we explore the increase in levels of deamidation in archaeological collagen, as measured during Zooarchaeology by Mass Spectrometry (ZooMS) analysis.\n\n\nMETHODS\nWith the high sensitivity of current generation mass spectrometers, ZooMS provides a non-destructive and highly cost-effective method to characterise collagen peptides. Deamidation can be detected by mass spectrometry as a +0.984 Da mass shift; therefore, aside from its original purpose, peptide mass-fingerprinting for bone identification, ZooMS concurrently yields a 'thermal indicator' of the samples.\n\n\nRESULTS\nBy analysis of conventional ZooMS spectra, we determined the deamidation rate for glutamine residues in 911 bone collagen samples from 50 sites, with ages varying from medieval to Palaeolithic. The degree of deamidation was compared to diagenetic parameters and nearby sequence properties.\n\n\nCONCLUSIONS\nThe extent of deamidation was found to be influenced more by burial conditions and thermal age than, for example, chronological age, the extent of bioerosion or crystallinity. The method lends itself mostly to screening heterogenic deposits of bone to identify outliers.", "keyphrases": ["deamidation", "marker", "collagen peptide", "glutamine residue"]}
{"id": "paleo.004477", "title": "A new diplodocoid sauropod dinosaur from the Upper Jurassic Morrison Formation of Montana, USA", "abstract": "A partial skeleton of a new sauropod dinosaur from the Upper Jurassic Morrison Formation (?Tithonian) of Montana is described. Suuwassea emilieae gen. et sp. nov. is diagnosed by numerous cranial, axial, and appendicular autapomorphies. The holotype consists of a premaxilla, partial maxilla, quadrate, braincase with partial skull roof, several partial and complete cranial and middle cervical, cranial dorsal, and caudal vertebrae, ribs, complete scapulocoracoid, humerus, partial tibia, complete fibula, calcaneus, and partial pes. It displays numerous synapomorphies of the Diplodocoidea, including characters of both the Diplodocidae (Apatosaurus + (Diplodocus + Barosaurus)) and Dicraeosauridae (Dicraeosaurus + Amargasaurus). Preliminary phylogenetic analysis indicates that Suuwassea is a diplodocoid more derived than rebbachisaurids but in a trichotomy with both the Diplodocidae and Dicraeosauridae. Suuwassea represents the first well-supported, North American, non-diplodocid representative of the Diplodocoidea and provides new insight into the origins of both the Diplodocidae and Dicraeosauridae.", "keyphrases": ["montana", "suuwassea", "holotype", "phylogenetic analysis"]}
{"id": "10.1002/bies.201100001", "title": "Cephalopod origin and evolution: A congruent picture emerging from fossils, development and molecules", "abstract": "Cephalopods are extraordinary molluscs equipped with vertebrate\u2010like intelligence and a unique buoyancy system for locomotion. A growing body of evidence from the fossil record, embryology and Bayesian molecular divergence estimations provides a comprehensive picture of their origins and evolution. Cephalopods evolved during the Cambrian (\u223c530\u2009Ma) from a monoplacophoran\u2010like mollusc in which the conical, external shell was modified into a chambered buoyancy apparatus. During the mid\u2010Palaeozoic (\u223c416\u2009Ma) cephalopods diverged into nautiloids and the presently dominant coleoids. Coleoids (i.e. squids, cuttlefish and octopods) internalised their shells and, in the late Palaeozoic (\u223c276\u2009Ma), diverged into Vampyropoda and the Decabrachia. This shell internalisation appears to be a unique evolutionary event. In contrast, the loss of a mineralised shell has occurred several times in distinct coleoid lineages. The general tendency of shell reduction reflects a trend towards active modes of life and much more complex behaviour.", "keyphrases": ["coleoid", "cuttlefish", "cephalopod", "ammonoid"]}
{"id": "10.1002/2017PA003098", "title": "Diploastrea heliopora Sr/Ca and \u03b418O records from northeast Luzon, Philippines : an assessment of interspecies coral proxy calibrations and climate controls of sea surface temperature and salinity", "abstract": "The Indo-Pacific coral Diploastrea heliopora reveals regional multidecadalto centennialscale climate variability using coral carbonate \u03b4O (\u03b4Oc) as a combined proxy for sea surface temperature (SST) and sea surface salinity (SSS). However, to assess the coral\u2019s full potential in resolving climatic events, an independent SST proxy would be more advantageous. We examined both Sr/Ca and \u03b4O of Diploastrea against an adjacent Porites lobata core collected from northeast Luzon, Philippines. Winter Sr/Ca data from Diploastrea show a significant correlation to SST (r = 0.41, p < 0.05, (root-mean-square of the residual) RMSR = 0.81\u00b0C) and provide a proxy with similar sensitivity as Porites (r = 0.57, p< 0.05, RMSR = 0.62\u00b0C). An interspecies SST record is shown to be robust and used for a reconstruction of the Pacific Decadal Oscillation during boreal winter (r = 0.70, p = 0.02). While we were unable to generate a robust Diploastrea \u03b4O-SSS calibration at interannual timescale, the freshening trend toward the present, commonly observed in the region, is qualitatively captured in Diploastrea \u03b4O. Comparison with Porites \u03b4O and instrumental SSS records shows that the magnitude of freshening is consistent between coral species. Wet and dry season Porites \u03b4O provide support for the relative influence of El Ni\u00f1o\u2013Southern Oscillation events and local precipitation to SSS variability at our site. The multiproxy, multispecies approach of this study further strengthens the evidence for Diploastrea as an alternate climate archive in the Indo-Pacific region and seals its potential in helping resolve less understood global-scale climate phenomena.", "keyphrases": ["northeast luzon", "philippines", "coral", "sea surface temperature", "timescale"]}
{"id": "paleo.001465", "title": "Tracing the effects of eutrophication on molluscan communities in sediment cores: outbreaks of an opportunistic species coincide with reduced bioturbation and high frequency of hypoxia in the Adriatic Sea", "abstract": "Estimating the effects and timing of anthropogenic impacts on the composition of macrobenthic communities is challenging, because early twentieth-century surveys are sparse and the corresponding intervals in sedimentary sequences are mixed by bioturbation. Here, to assess the effects of eutrophication on macrobenthic communities in the northern Adriatic Sea, we account for mixing with dating of the bivalve Corbula gibba at two stations with high accumulation (Po prodelta) and one station with moderate accumulation (Isonzo prodelta). We find that, first, pervasively bioturbated muds typical of highstand conditions deposited in the early twentieth century were replaced by muds with relicts of flood layers and high content of total organic carbon (TOC) deposited in the late twentieth century at the Po prodelta. The twentieth century shelly muds at the Isonzo prodelta are amalgamated but also show an upward increase in TOC. Second, dating of C. gibba shells shows that the shift from the early to the late twentieth century is characterized by a decrease in stratigraphic disorder and by an increase in temporal resolution of assemblages from ~25-50 years to ~10-20 years in both regions. This shift reflects a decline in the depth of the fully mixed layer from more than 20 cm to a few centimeters. Third, the increase in abundance of the opportunistic species C. gibba and the loss of formerly abundant, hypoxia-sensitive species coincided with the decline in bioturbation, higher preservation of organic matter, and higher frequency of seasonal hypoxia in both regions. This depositional and ecosystem regime shift occurred in ca. A.D. 1950. Therefore, the effects of enhanced food supply on macrobenthic communities were overwhelmed by oxygen depletion, even when hypoxic conditions were limited to few weeks per year in the northern Adriatic Sea. Preservation of trends in molluscan abundance and flood events in cores was enhanced by higher frequency of hypoxia that reduced bioturbation in the late twentieth century.", "keyphrases": ["eutrophication", "bioturbation", "hypoxia"]}
{"id": "10.1029/2011PA002117", "title": "Early Holocene temperature variability in the Nordic Seas: The role of oceanic heat advection versus changes in orbital forcing", "abstract": "Received 7 January 2011; revised 15 July 2011; accepted 21 July 2011; published 22 October 2011. [1] The separate roles of oceanic heat advection and orbital forcing on influencing early Holocene temperature variability in the eastern Nordic Seas is investigated. The effect of changing orbital forcing on the ocean temperatures is tested using the 1DICE model, and the 1DICE results are compared with new and previously published temperature reconstructions from a transect of five cores located underneath the pathway of Atlantic water, from the Faroe\u2010Shetland Channel in the south to the Barents Sea in the north. The stronger early Holocene summer insolation at high northern latitudes increased the summer mixed layer temperatures, however, ocean temperatures underneath the summer mixed layer did not increase significantly. The absolute maximum in summer mixed layer temperatures occurred between 9 and 6 ka BP, representing the Holocene Thermal Maximum in the eastern Nordic Seas. In contrast, maximum in northward oceanic heat transport through the Norwegian Atlantic Current occurred approximately 10 ka BP. The maximum in oceanic heat transport at 10 ka BP occurred due to a major reorganization of the Atlantic Ocean circulation, entailing strong and deep rejuvenation of the Atlantic Meridional Overturning Circulation, combined with changes in the North Atlantic gyre dynamic causing enhanced transport of heat and salt into the Nordic Seas.", "keyphrases": ["holocene temperature variability", "oceanic heat advection", "orbital forcing", "heat transport"]}
{"id": "paleo.004412", "title": "Antitropicality and convergent evolution: a case study of Permian neospiriferine brachiopods", "abstract": "Antitropical distribution is a biogeographical pattern characterized by natural occurrences of the same species or members of the same clade in the middle\u2010 or middle\u2010to\u2010high\u2010latitudinal habitats of both hemispheres, either on land or in marine environments, without appearing in the intervening tropical environments. For most of the noted examples of Permian antitropical distribution, particularly in marine invertebrates, the causes of disjunctions have been mainly linked to either dispersal or vicariance models. Little attention has been paid to other possible mechanisms. This study investigated the antitropicality of some Permian neospiriferine brachiopods through detailed taxonomic revision, comparison of palaeobiogeographical distribution, and a phylogenetic analysis. Several species, previously assigned to Kaninospirifer, are here reassigned to other genera, especially to Fasciculatia in the northern hemisphere and to Quadrospira in the southern hemisphere during the Permian. Both Kaninospirifer and Fasciculatia appear to have been restricted to north\u2010western Pangea and north\u2010eastern Asia during the Permian, but there is no robust evidence to suggest their presence in the southern hemisphere to which Imperiospira and Quadrospira were confined. In spite of the distributional separation between the two pairs of neospiriferine genera in the Permian palaeobiogeographical regime, they share considerable numbers of morphological characters, such as a large shell, subdued fasciculation, and reduction of ventral adminicula. Notwithstanding these morphological similarities, our phylogenetic reconstruction of the neospiriferines does not support a close relationship between these genera. This therefore must indicate that these similar morphological features were independently acquired, probably with these taxa living in spatially separate but ecologically compatible environmental conditions in the mid\u2010latitudinal area of each hemisphere during the Permian. We regard this as an example of convergent evolution.", "keyphrases": ["convergent evolution", "permian neospiriferine brachiopod", "antitropicality"]}
{"id": "paleo.007127", "title": "Biostratigraphical and palaeoecological implications of the small mammal assemblage from the late early Miocene of Montalvos2, Teruel Basin, Spain", "abstract": "The rich early Miocene small mammal assemblage from Montalvos2, collected from lacustrine deposits directly overlying the basement, is unique within the Teruel Basin, a basin that is otherwise well known for its late Miocene/ Pliocene mammal faunas. The presence of Democricetodon decipiens, Megacricetodon primitivus, Eumyarion and Ligerimys ellipticus enables correlation with the local biozone Ca (approx. 16.3 Ma, MN4). The high percentage of ochotonids in Montalvos2 is remarkable, a phenomenon that is known to occur in older assemblages from the adjacent Calatayud-Montalb\u00e1n Basin. The association in Montalvos2 includes species indicative of an arid biotope, such as the ochotonid Lagopsis penai and the rodents Simplomys simplicidens, Armantomys aragonensis, Melissiodon dominans and the xerine squirrel Heteroxerus, and species that are supposed to have lived in a more humid forested biotope, such as the Talpidae and the flying squirrel Albanensia. This wide range of species indicates that the en-vironment in the Teruel Basin was highly diverse during the early Miocene.", "keyphrases": ["small mammal assemblage", "early miocene", "teruel basin"]}
{"id": "10.1111/evo.13106", "title": "From success to persistence: Identifying an evolutionary regime shift in the diverse Paleozoic aquatic arthropod group Eurypterida, driven by the Devonian biotic crisis", "abstract": "Mass extinctions have altered the trajectory of evolution a number of times over the Phanerozoic. During these periods of biotic upheaval a different selective regime appears to operate, although it is still unclear whether consistent survivorship rules apply across different extinction events. We compare variations in diversity and disparity across the evolutionary history of a major Paleozoic arthropod group, the Eurypterida. Using these data, we explore the group's transition from a successful, dynamic clade to a stagnant persistent lineage, pinpointing the Devonian as the period during which this evolutionary regime shift occurred. The late Devonian biotic crisis is potentially unique among the \u201cBig Five\u201d mass extinctions in exhibiting a drop in speciation rates rather than an increase in extinction. Our study reveals eurypterids show depressed speciation rates throughout the Devonian but no abnormal peaks in extinction. Loss of morphospace occupation is random across all Paleozoic extinction events; however, differential origination during the Devonian results in a migration and subsequent stagnation of occupied morphospace. This shift appears linked to an ecological transition from euryhaline taxa to freshwater species with low morphological diversity alongside a decrease in endemism. These results demonstrate the importance of the Devonian biotic crisis in reshaping Paleozoic ecosystems.", "keyphrases": ["evolutionary regime shift", "paleozoic", "devonian biotic crisis"]}
{"id": "10.1144/jgs2017-143", "title": "The Carnian Pluvial Episode and the first global appearance of amber", "abstract": "Amber (fossil resin) is not common throughout the fossil record, and previously the only globally significant deposits were thought to occur during the Cretaceous, Eocene, Oligocene and Miocene periods. Recent finds of Late Triassic (Carnian) ambers highlight a significantly older set of deposits. Here we review these ambers that appear coincident with the Carnian Pluvial Episode, a time interval of major climate change and biotic turnover. Much of the amber is found in a palaeolatitudinal belt between 5\u00b0 and 30\u00b0 N, and covers Italian, Austrian, Swiss, Hungarian, Spanish and Arizona (USA) deposits, with one exception from Lesotho, Southern Africa (c. 40\u00b0 S). Most deposits are small and allochthonous, with the major exception of the autochthonous\u2013parautochthonous amber deposit found as droplets in a palaeosol from the Dolomites (Italy). In some of these deposits there is even direct evidence of the source plants that produced the preserved resin. The oldest confirmed organisms found preserved in amber are from Carnian droplets from the Dolomites in Italy and include arthropods and microorganisms. The occurrence of amber in different localities and within the same time interval suggests a widespread stressed flora, and major biological turnover in the terrestrial ecosystems during the Carnian Pluvial Episode.", "keyphrases": ["carnian pluvial episode", "amber", "resin", "production", "amber forest"]}
{"id": "paleo.010013", "title": "The Global Diversity of Parasitic Isopods Associated with Crustacean Hosts (Isopoda: Bopyroidea and Cryptoniscoidea)", "abstract": "Parasitic isopods of Bopyroidea and Cryptoniscoidea (commonly referred to as epicarideans) are unique in using crustaceans as both intermediate and definitive hosts. In total, 795 epicarideans are known, representing \u223c7.7% of described isopods. The rate of description of parasitic species has not matched that of free-living isopods and this disparity will likely continue due to the more cryptic nature of these parasites. Distribution patterns of epicarideans are influenced by a combination of their definitive (both benthic and pelagic species) and intermediate (pelagic copepod) host distributions, although host specificity is poorly known for most species. Among epicarideans, nearly all species in Bopyroidea are ectoparasitic on decapod hosts. Bopyrids are the most diverse taxon (605 species), with their highest diversity in the North West Pacific (139 species), East Asian Sea (120 species), and Central Indian Ocean (44 species). The diversity patterns of Cryptoniscoidea (99 species, endoparasites of a diverse assemblage of crustacean hosts) are distinct from bopyrids, with the greatest diversity of cryptoniscoids in the North East Atlantic (18 species) followed by the Antarctic, Mediterranean, and Arctic regions (13, 12, and 8 species, respectively). Dajidae (54 species, ectoparasites of shrimp, mysids, and euphausids) exhibits highest diversity in the Antarctic (7 species) with 14 species in the Arctic and North East Atlantic regions combined. Entoniscidae (37 species, endoparasites within anomuran, brachyuran and shrimp hosts) show highest diversity in the North West Pacific (10 species) and North East Atlantic (8 species). Most epicarideans are known from relatively shallow waters, although some bopyrids are known from depths below 4000 m. Lack of parasitic groups in certain geographic areas is likely a sampling artifact and we predict that the Central Indian Ocean and East Asian Sea (in particular, the Indo-Malay-Philippines Archipelago) hold a wealth of undescribed species, reflecting our knowledge of host diversity patterns.", "keyphrases": ["crustacean host", "bopyroidea", "epicaridean", "ectoparasite", "cuticle"]}
{"id": "10.1017/S1755691011020019", "title": "The beginning of the \u2018Age of Dinosaurs\u2019: a brief overview of terrestrial biotic changes during the Triassic", "abstract": "ABSTRACT The first appearance of dinosaurs during the early Late Triassic coincided with marked faunal changes in terrestrial ecosystems. Most of the major groups of extant tetrapods (or their proximate sister-taxa), including mammaliaforms, crocodyliform archosaurs, lepidosaurs and turtles, also first appeared in the fossil record during the Late Triassic. On the other hand, a number of Palaeozoic \u2018holdovers\u2019, such as procolophonid parareptiles, dicynodont therapsids and many groups of temnospondyls, vanished near or at the end of the Triassic. The tempo and mode of this faunal turnover have long been debated, but there has been growing acceptance of a rather sudden event, although the precise dating of such an event remains controversial. However, new discoveries have cast doubt on this assumption. The persistence of non-dinosaurian dinosauromorphs alongside dinosaurs well into Norian times hints at a more protracted turnover. New data on Triassic insect assemblages indicate that turnover among insects may also have been more protracted and possibly not co-incident with the faunal changes among tetrapods. Future work directed toward improved absolute age assessments for major faunal assemblages will be critical for a better understanding of the transition from therapsid-dominated to dinosaur-dominated communities during the early Mesozoic.", "keyphrases": ["triassic", "mammaliaform", "lepidosaur", "turtle"]}
{"id": "paleo.007841", "title": "The morphospace of Late Permian coiled nautiloids", "abstract": "Occurrences of Late Permian coiled nautiloids are widespread but they have never been analysed in terms of spatial and temporal disparity changes. Morphometric analyses using the cardinal Raupian conch parameters: conch width index, umbilical width index and whorl expansion rate with subsequent analysis by using principal components analysis and non\u2010metric multidimensional scaling, allow the construction of a nautiloid morphospace. The analyses show that there is a stable disparity in the coiled nautiloids from the Wuchiapingian to the Changhsingian. Differences between the three major Late Permian nautiloid occurrences (Salt Range, South China and Transcaucasus\u2010NW Iran) are considerably small; the South Chinese occurrences, however, are characterized by many endemic genera. The most important variation in morphospace occupation is caused by environmental differences such as water depth. \u25a1 Changhsingian, disparity, morphospace, Nautilida, palaeogeography, Wuchiapingian.", "keyphrases": ["morphospace", "late permian", "nautiloid"]}
{"id": "paleo.008110", "title": "Small shelly fossils from the argillaceous facies of the Lower Cambrian Forteau Formation of western Newfoundland", "abstract": "A diverse fauna of helcionelloid molluscs, hyoliths, and other small shelly fossils is described from limestone layers within the Forteau Formation of the Bonne Bay region in western Newfoundland. The fauna is dominated by internal moulds of various molluscs and tubular problematica, but also includes hyolith opercula, echinoderm ossicles, and other calcareous small shelly fossils preserved by phosphatisation. Originally organophosphatic shells are comparatively rare, but are represented by brachiopods, hyolithelminths, and tommotiids. The fauna is similar to other late Early Cambrian faunas from slope and outer shelf settings along the eastern margin of Laurentia and may be of middle Dyeran age. The similarity of these faunas indicates that at least by the late Early Cambrian, a distinctive and laterally continuous outer shelf fauna had evolved. The Forteau Formation also shares elements with faunas from other Early Cambrian provinces, strengthening ties between Laurentia and Australia, China, and Europe during the late Early Cambrian. Two new taxa of problematic fossil organisms are described, the conical Clavitella curvata gen. et sp. nov. and the wedge-shaped Sphenopteron boomerang gen. et sp. nov.", "keyphrases": ["forteau formation", "western newfoundland", "small shelly fossil"]}
{"id": "paleo.011973", "title": "Conserved in-ovo cranial ossification sequences of extant saurians allow estimation of embryonic dinosaur developmental stages", "abstract": "Dinosaur embryos are among the rarest of fossils, yet they provide a unique window into the palaeobiology of these animals. Estimating the developmental stage of dinosaur embryos is hindered by the lack of a quantitative method for age determination, by the scarcity of material, and by the difficulty in visualizing that material. Here we present the results of a broad inquiry, using 3D reconstructions from X-ray computed tomography data, into cranial ossification sequences in extant saurian taxa and in well-preserved embryos of the early branching sauropodomorph dinosaur Massospondylus carinatus. Our findings support deep-time conservation of cranial ossification sequences in saurians including dinosaurs, allowing us to develop a new method for estimating the relative developmental percentage of embryos from that clade. We also observe null-generation teeth in the Massospondylus carinatus embryos which get resorbed or shed before hatching, similar to those of geckos. These lines of evidence allow us to confidently estimate that the Massospondylus carinatus embryos are only approximately 60% through their incubation period, much younger than previously hypothesized. The overall consistency of our results with those of living saurians indicates that they can be generalized to other extinct members of that lineage, and therefore our method provides an independent means of assessing the developmental stage of extinct, in-ovo saurians.", "keyphrases": ["cranial ossification sequence", "saurians", "developmental stage"]}
{"id": "paleo.007721", "title": "ON THE TUBE ULTRASTRUCTURE AND ORIGIN OF CALCIFICATION IN SABELLIDS (ANNELIDA, POLYCHAETA)", "abstract": "Abstract:\u2002 Tube ultrastructure of Jurassic and Cretaceous Glomerula is very similar to that of Recent Calcisabella, supporting the synonymy of these genera and the early Mesozoic origin of calcification in sabellids. Tube structure of serpulids differs from that of Glomerula; calcareous tubes probably evolved convergently within Sabellida. The tube wall in Recent Glomerula piloseta is composed of subparallel lamellae of aragonitic, irregular spherulitic prisms in the inner layer, and spherulites in the outer layer. Calcified lamellae are separated by organic films of different thickness. The structure of the internal tube layer in Glomerula piloseta, and the structure of entire wall in fossil Glomerula, are similar to the tube structure of Dodecaceria (Polychaeta, Cirratulidae). The irregular spherulitic prisms of Glomerula are similar to those found in the external layer of Hydroides dianthus and the internal layer of Spiraserpula caribensis.", "keyphrases": ["tube ultrastructure", "calcification", "polychaeta"]}
{"id": "10.1080/03115518.2010.496529", "title": "A middle Cambrian fauna of skeletal fossils from the Kuonamka Formation, northern Siberia", "abstract": "An assemblage of mineralized skeletal fossils containing molluscs, hyoliths, chancelloriids, protoconodonts, lobopods, paleoscolecids, bradoriids, echinoderms and hexactinellid sponges is described from the middle Cambrian part of the Kuonamka Formation, exposed along the Malaya Kuonamka and Bol'shaya Kuonamka rivers, northern Siberian Platform. The sampled succession is attributed to the Kuonamkites and lower Tomagnostus fissus\u2013Paradoxides sacheri biozones of the Amgan Stage of Siberia, correlated with Series 3, Stage 5\u2014lower Drumian Stage of the IUGS chronostratigraphical scheme for the Cambrian. This work complements descriptions of molluscs from the same samples published by Gubanov et al. (2004) with additional material. It contains forms in common with coeval faunas from Australia, China, Western Gondwana, Avalonia, Laurentia and Baltica, increasing potential for global biostratigraphic correlation and understanding of palaeogeographic connections.", "keyphrases": ["skeletal fossil", "kuonamka formation", "bol'shaya kuonamka river", "northern siberian platform"]}
{"id": "paleo.000311", "title": "A new method to determine volume of bromalites: morphometrics of Lower Permian (Archer City Formation) heteropolar bromalites", "abstract": "Lower Permian vertebrates from both terrestrial and aquatic organisms have been collected from Archer County, Texas, for over a century. These include preserved shark cartilage and spiral bromalites presumed to have been produced by freshwater sharks of the genus Orthacanthus. Specimens were collected in the newly named Archer City Bonebed V occurring in the Archer City Formation. Physical characteristics (length, width, height, mass, eccentricity, volume, and density) were measured and recorded for 300 spiral bromalites and compared by linear regression analysis. The spiral bromalites had an average length of 31.74 mm; width 14.43 mm; height 10.51 mm, and mass 7.971 g. Eccentricity ranged from 0.9 to 0.06. All of these values follow a normal distribution. In addition to the collection of this statistical data, a new formula is proposed to help determine the volume of these elliptical fossils when volume determination by water displacement is not an option. The percent difference between the observed volumes obtained by water displacement and calculated volumes ranged from 0.04 to 56 %. Ninety-five percent of the statistical sample had a percentage difference of \\30. This data, if compiled with data from the analysis of specimens from other localities, may ultimately reveal size groupings that could reflect the presence of previously unknown taxa that possessed a spiral valve and coexisted with the Orthacanthus sharks.", "keyphrases": ["volume", "bromalite", "archer city formation"]}
{"id": "10.1139/cjes-2015-0061", "title": "A new elasmobranch assemblage from the early Eocene (Ypresian) Fishburne Formation of Berkeley County, South Carolina, USA", "abstract": "A rich elasmobranch assemblage was recovered from the early Eocene (Ypresian) Fishburne Formation in a limestone quarry at Jamestown, Berkeley County, South Carolina, USA. Reported herein are 22 species belonging to 8 orders, at least 15 families, and 21 genera. It includes the first occurrence of Protoginglymostoma from North America. Many of the reported species have large palaeobiogeographical ranges and inhabited waters on both sides of the Atlantic, whereas others were endemic to the east coast of North America. The paucity of sizeable dentition from several of the larger species in this assemblage, and the apparent absence of relatively large macrophagous species found in contemporaneous deposits elsewhere, suggests the Jamestown site may represent a nursery ground and refuge for young and smaller individuals.", "keyphrases": ["elasmobranch assemblage", "early eocene", "fishburne formation"]}
{"id": "10.1666/07008.1", "title": "The Red Queen revisited: reevaluating the age selectivity of Phanerozoic marine genus extinctions", "abstract": "Abstract Extinction risk is inversely related to genus age (time since first appearance) in most intervals of the Phanerozoic marine fossil record, in apparent contradiction to the macroevolutionary Red Queen's Hypothesis, which posits that extinction risk is independent of taxon age. Age-dependent increases in the mean species richness and geographic range of genera have been invoked to reconcile this genus-level observation with the presumed prevalence of Red Queen dynamics at the species level. Here we test these explanations with data from the Paleobiology Database. Multiple logistic regression demonstrates that the association of extinction risk with genus age is not adequately explained by species richness or geographic range: there is a residual association between age and extinction risk even when range and richness effects are accounted for. Throughout most of the Phanerozoic the age selectivity gradient is highest among the youngest age cohorts, whereas there is no association between age and extinction risk among older age cohorts. Some of the apparent age selectivity of extinction in the global fauna is attributable to differences in extinction rate among taxonomic groups, but extinction risk declines with genus age even within most taxonomic orders. Notable exceptions to this pattern include the Cambrian\u2013Ordovician, latest Permian, Triassic, and Paleocene intervals. The association of age with extinction risk could reflect sampling heterogeneity or taxonomic practice more than biological reality, but at present it is difficult to evaluate or correct for such biases. Alternatively, the pattern may reflect consistent extinction selectivity on some as-yet unidentified covariate of genus age. Although this latter explanation is not compatible with a Red Queen model if most genus extinctions have resulted from biological interactions, it may be applicable if most genus extinctions have instead been caused by recurrent physical disturbances that repeatedly impose similar selective pressures.", "keyphrases": ["age selectivity", "phanerozoic", "genus extinction"]}
{"id": "paleo.003446", "title": "Increased pliosaurid dental disparity across the Jurassic\u2013Cretaceous transition", "abstract": "Pliosaurid marine reptiles played important roles in marine food chains from the Middle Jurassic to the middle Cretaceous, frequently as apex predators. The evolution of pliosaurids during the later parts of the Early Cretaceous has recently been illuminated by discoveries from Russia (Hauterivian) and Colombia (Barremian). However, knowledge of pliosaurids representing the Jurassic\u2013Cretaceous transition (late Tithonian \u2013 Valanginian), is still largely incomplete, especially during the earliest Cretaceous. As such, the effect on pliosaurids of hypothesized faunal turnover during the Jurassic\u2013Cretaceous boundary interval is poorly understood. We report pliosaurid teeth from the upper Volgian (Tithonian, Upper Jurassic) of the Kheta river basin (Eastern Siberia, Russia), to the Berriasian and Valanginian (Lower Cretaceous) of the Volga region (European Russia). These assemblages have yielded a series of distinct tooth morphotypes, including the first reports of conical\u2010toothed pliosaurids from the latest Jurassic and earliest Cretaceous. This challenges the hypothesis that only one lineage of pliosaurids crossed the Jurassic\u2013Cretaceous boundary. It appears that conical\u2010toothed pliosaurids co\u2010existed with their trihedral\u2010toothed relatives for at least 25 million years during the latest Jurassic and earliest Cretaceous. In fact, our quantitative analyses indicate that pliosaurids reached their maximal dental disparity during this interval, showing little evidence of turnover associated with the Jurassic\u2013Cretaceous transition. Instead, disparity decreased later in the Early Cretaceous, with the disappearance of trihedral\u2010toothed forms in the Barremian.", "keyphrases": ["pliosaurid", "dental disparity", "jurassic\u2013cretaceous transition", "late jurassic"]}
{"id": "paleo.007321", "title": "Scale morphology and squamation pattern of Guiyu oneiros provide new insights into early osteichthyan body plan", "abstract": "Scale morphology and squamation play an important role in the study of fish phylogeny and classification. However, as the scales of the earliest osteichthyans or bony fishes are usually found in a disarticulated state, research into squamation patterns and phylogeny has been limited. Here we quantitatively describe the scale morphology of the oldest articulated osteichthyan, the 425-million-year-old Guiyu oneiros, based on geometric morphometrics and high-resolution computed tomography. Based on the cluster analysis of the scales in the articulated specimens, we present a squamation pattern of Guiyu oneiros, which divides the body scales into 4 main belts, comprising 16 areas. The new pattern reveals that the squamation of early osteichthyans is more complicated than previously known, and demonstrates that the taxa near the crown osteichthyan node in late Silurian had a greater degree of squamation zonation compared to more advanced forms. This study offers an important reference for the classification of detached scales of early osteichthyans, provides new insights into the early evolution of osteichthyan scales, and adds to our understanding of the early osteichthyan body plan.", "keyphrases": ["squamation pattern", "osteichthyan body plan", "scale morphology"]}
{"id": "10.1002/2016pa003032", "title": "GDGT and alkenone flux in the northern Gulf of Mexico: Implications for the TEX86 and UK'37 paleothermometers", "abstract": "The TEX86 and U37K' molecular biomarker proxies have been broadly applied in downcore marine sediments to reconstruct past sea surface temperature (SST). Although both TEX86 and U37K' have been interpreted as proxies for mean annual SST throughout the global ocean, regional studies of glycerol dibiphytanyl glycerol tetraethers (GDGTs) and alkenones in sinking particles are required to understand the influence of seasonality, depth distribution, and diagenesis on downcore variability. We measure GDGT and alkenone flux, as well as the TEX86 and U37K' indices in a 4\u2009year sediment trap time series (2010\u20132014) in the northern Gulf of Mexico (nGoM), and compare these data with core-top sediments at the same location. GDGT and alkenone fluxes do not show a consistent seasonal cycle; however, the largest flux peaks for both occurs in winter. U37K' covaries with SST over the 4\u2009year sampling interval, but the U37K'-SST relationship in this data set implies a smaller slope or nonlinearity at high temperatures when compared with existing calibrations. Furthermore, the flux-weighted U37K' value from sinking particles is significantly lower than that of underlying core-top sediments, suggesting preferential diagenetic loss of the tri-unsaturated alkenone in sediments. TEX86 does not covary with SST, suggesting production in the subsurface upper water column. The flux-weighted mean TEX86 matches that of core-top sediments, confirming that TEX86 in the nGoM reflects local planktonic production rather than allochthonous or in situ sedimentary production. We explore potential sources of uncertainty in both proxies in the nGoM but demonstrate that they show nearly identical trends in twentieth century SST, despite these factors.", "keyphrases": ["alkenone flux", "northern gulf", "mexico"]}
{"id": "10.1371/journal.pone.0188426", "title": "Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America", "abstract": "Interbasinal stratigraphic correlation provides the foundation for all consequent continental-scale geological and paleontological analyses. Correlation requires synthesis of lithostratigraphic, biostratigraphic and geochronologic data, and must be periodically updated to accord with advances in dating techniques, changing standards for radiometric dates, new stratigraphic concepts, hypotheses, fossil specimens, and field data. Outdated or incorrect correlation exposes geological and paleontological analyses to potential error. The current work presents a high-resolution stratigraphic chart for terrestrial Late Cretaceous units of North America, combining published chronostratigraphic, lithostratigraphic, and biostratigraphic data. 40Ar / 39Ar radiometric dates are newly recalibrated to both current standard and decay constant pairings. Revisions to the stratigraphic placement of most units are slight, but important changes are made to the proposed correlations of the Aguja and Javelina formations, Texas, and recalibration corrections in particular affect the relative age positions of the Belly River Group, Alberta; Judith River Formation, Montana; Kaiparowits Formation, Utah; and Fruitland and Kirtland formations, New Mexico. The stratigraphic ranges of selected clades of dinosaur species are plotted on the chronostratigraphic framework, with some clades comprising short-duration species that do not overlap stratigraphically with preceding or succeeding forms. This is the expected pattern that is produced by an anagenetic mode of evolution, suggesting that true branching (speciation) events were rare and may have geographic significance. The recent hypothesis of intracontinental latitudinal provinciality of dinosaurs is shown to be affected by previous stratigraphic miscorrelation. Rapid stepwise acquisition of display characters in many dinosaur clades, in particular chasmosaurine ceratopsids, suggests that they may be useful for high resolution biostratigraphy.", "keyphrases": ["stratigraphic range", "north america", "radiometric date", "alberta"]}
{"id": "paleo.004828", "title": "THE EXTRAORDINARY TRILOBITE FENESTRASPIS (DALMANITIDAE, SYNPHORIINAE) FROM THE LOWER DEVONIAN OF BOLIVIA", "abstract": "Abstract: The hitherto poorly known, monotypic trilobite genus Fenestraspis from the Lower Devonian of Bolivia is revised and its original assignment to the Synphoriinae supported. The thoracic morphology of the genus remains very poorly known. Fenestraspis is morphologically unusual because of the development of extensive fenestrae in the pleural region of the pygidium and apparently of the thorax; the presence of upwardly directed spines on the cephalon, thorax and pygidium; and the exceptionally large and highly elevated eyes with the palpebral rim projecting outwards above the visual surface. The function of the fenestrae remains uncertain. If they formed openings in the body of the trilobite in life they may have allowed circulation of oxygenated water to the limb exites so that respiration could have been maintained while the trilobite was enrolled. If they were covered with a flexible membrane, they may have been secondary respiratory structures or had a sensory function. The Synphoriinae is regarded as a subfamily of the Dalmanitidae rather than as an independent family of the Dalmanitoidea as proposed by some authors. The type species of the poorly known monotypic genus Dalmanitoides from the Lower Devonian of Argentina is illustrated photographically for the first time and compared with Fenestraspis.", "keyphrases": ["dalmanitidae", "synphoriinae", "devonian"]}
{"id": "10.1371/journal.pone.0193522", "title": "Terminal Pleistocene epoch human footprints from the Pacific coast of Canada", "abstract": "Little is known about the ice age human occupation of the Pacific Coast of Canada. Here we present the results of a targeted investigation of a late Pleistocene shoreline on Calvert Island, British Columbia. Drawing upon existing geomorphic information that sea level in the area was 2\u20133 m lower than present between 14,000 and 11,000 years ago, we began a systematic search for archaeological remains dating to this time period beneath intertidal beach sediments. During subsurface testing, we uncovered human footprints impressed into a 13,000-year-old paleosol beneath beach sands at archaeological site EjTa-4. To date, our investigations at this site have revealed a total of 29 footprints of at least three different sizes. The results presented here add to the growing body of information pertaining to the early deglaciation and associated human presence on the west coast of Canada at the end of the Last Glacial Maximum.", "keyphrases": ["human footprint", "pacific coast", "canada"]}
{"id": "paleo.002696", "title": "ROM mapping of ligamentous constraints on avian hip mobility: implications for extinct ornithodirans", "abstract": "Studies of soft tissue effects on joint mobility in extant animals can help to constrain hypotheses about joint mobility in extinct animals. However, joint mobility must be considered in three dimensions simultaneously, and applications of mobility data to extinct taxa require both a phylogenetically informed reconstruction of articular morphology and justifications for why specific structures' effects on mobility are inferred to be similar. We manipulated cadaveric hip joints of common quail and recorded biplanar fluoroscopic videos to measure a \u2018ligamentous\u2019 range of motion (ROM), which was then compared to an \u2018osteological\u2019 ROM on a ROM map. Nearly 95% of the joint poses predicted to be possible at the hip based on osteological manipulation were rendered impossible by ligamentous constraints. Because the hip joint capsule reliably includes a ventral ligamentous thickening in extant diapsids, the hip abduction of extinct ornithodirans with an offset femoral head and thin articular cartilage was probably similarly constrained by ligaments as that of birds. Consequently, in the absence of extraordinary evidence to the contrary, our analysis casts doubt on the \u2018batlike\u2019 hip pose traditionally inferred for pterosaurs and basal maniraptorans, and underscores that reconstructions of joint mobility based on manipulations of bones alone can be misleading.", "keyphrases": ["ligamentous constraint", "constraint", "extinct ornithodiran", "joint capsule", "cartilage"]}
{"id": "10.1017/S0022336000029395", "title": "The Sweetognathus complex in the Permian of China: implications for evolution and homeomorphy", "abstract": "The well-exposed and fossiliferous Permian carbonates in China have yielded Early and Late Permian species of the Sweetognathus complex that permit worldwide stratigraphic evaluation of members of the group. The sporadic appearance of species of Sweetognathus and related genera throughout the Permian in western North America and Iran, in particular, may represent iterative evolution and homeomorphy. The pectiniform element morphologies of the several species are interpreted as most important for evolutionary studies and document a partial Permian biostratigraphy in China that aids in the interpretation of less complete sequences elsewhere. A new genus, Pseudosweetognathus, and four new species, Pseudosweetognathus costatus, Sweetognathus subsymmetricus, S. paraguizhouensis, and Iranognathus nudus, are described.", "keyphrases": ["sweetognathus complex", "china", "homeomorphy"]}
{"id": "10.1666/07081.1", "title": "Preservation of spatial and environmental gradients by death assemblages", "abstract": "Abstract Although only a few studies have explicitly evaluated live-dead agreement of species and community responses to environmental and spatial gradients, paleoecological analyses implicitly assume that death assemblages capture these gradients accurately. We use nine data sets from modern, relatively undisturbed coastal study areas to evaluate how the response of living molluscan assemblages to environmental gradients (water depth and seafloor type; \u201cenvironmental component\u201d of a gradient) and geographic separation (\u201cspatial component\u201d) is captured by their death assemblages. We find that: 1. Living assemblages vary in composition either in response to environmental gradients alone (consistent with a species-sorting model) or in response to a combination of environmental and spatial gradients (mass-effect model). None of the living assemblages support the neutral model (or the patch-dynamic model), in which variation in species abundance is related to the spatial configuration of stations alone. These findings also support assumptions that mollusk species consistently differ in responses to environmental gradients, and suggest that in the absence of postmortem bias, environmental gradients might be accurately captured by variation in species composition among death assemblages. Death assemblages do in fact respond uniquely to environmental gradients, and show a stronger response when abundances are square-root transformed to downplay the impact of numerically abundant species and increase the effect of rare species. 2. Species' niche positions (position of maximum abundance) along bathymetric and sedimentary gradients in death assemblages show significantly positive rank correlations to species positions in living assemblages in seven of nine data sets (both square-root-transformed and presence-absence data). 3. The proportion of compositional variation explained by environmental gradients in death assemblages is similar to that of counterpart living assemblages. Death assemblages thus show the same ability to capture environmental gradients as do living assemblages. In some instances compositional dissimilarities in death assemblages show higher rank correlation with spatial distances than with environmental gradients, but spatial structure in community composition is mainly driven by spatially structured environmental gradients. 4. Death assemblages correctly identify the dominance of niche metacommunity models in mollusk communities, as revealed by counterpart living assemblages. This analysis of the environmental resolution of death assemblages thus supports fine-scale niche and paleoenvironmental analyses using molluscan fossil records. In spite of taphonomic processes and time-averaging effects that modify community composition, death assemblages largely capture the response of living communities to environmental gradients, partly because of redundancy in community structure that is inherently associated with multispecies assemblages. The molluscan data sets show some degree of redundancy as evidenced by the presence of at least two mutually exclusive subsets of species that replicate the community structure, and simple simulations show that between-sample relationships can be preserved and remain significant even when a large proportion of species is randomly removed from data sets.", "keyphrases": ["environmental gradient", "death assemblage", "living assemblage"]}
{"id": "paleo.004129", "title": "Talpa fossilis or Talpa europaea? Using geometric morphometrics and allometric trajectories of humeral moles remains from Hungary to answer a taxonomic debate", "abstract": "The taxonomic validity of Talpa fossilis has been subject to a longstanding debate. Talpa fossilis has been considered as a chronospecies, stratigraphic species, and finally as junior synonym of Talpa europaea. In this study, the large humeral sample of T. fossilis and T. europaea from the Plio-Pleistocene of Hungary is re-investigated using a geometric morphometrics analysis. Furthermore, the differences in the static allometric slopes under the allometric constraint hypothesis were tested. The results indicate that T. fossilis and T. europaea have significant differences in both size and shape. The allometric slopes of T. fossilis and T. europaea were found to be different, revealing that the two taxa follow different patterns of shape modification according to size. In light of this evidence, T. fossilis and T. europaea are supported as two distinct species.", "keyphrases": ["fossilis", "talpa europaea", "geometric morphometric"]}
{"id": "10.1371/journal.pone.0098462", "title": "Assessing Raman Spectroscopy as a Prescreening Tool for the Selection of Archaeological Bone for Stable Isotopic Analysis", "abstract": "Stable isotope analyses for paleodiet investigations require good preservation of bone protein, the collagen, to obtain reliable stable isotope values. Burial environments cause diagenetic alterations to collagen, especially in the leaching of the organic bone content. The survival of bone protein may be assessed by the weight % collagen, % carbon and % nitrogen yields, but these values are achieved only after destructive chemical processing. A non-destructive method of determining whether bone is suitably preserved would be desirable, as it would be less costly than chemical processing, and would also preserve skeletal collections. Raman analysis is one such potential non-destructive screening method. In previous applications, Raman spectroscopy has been used to test both the alteration of the mineral portion of bone, as well as to indicate the relative amount of organic material within the bone structure. However, there has been no research to test the relationship between the Raman spectroscopic results and the survival of bone protein. We use a set of 41 bone samples from the prehistoric archaeological site of Ban Non Wat, Northeast Thailand, to assess if Raman spectroscopy analysis of the organic-phosphate ratio has a significant correlation with the weight % collagen, and carbon and nitrogen yields obtained by isotopic analysis. The correlation coefficients are highly statistically significant in all cases (r\u200a=\u200a0.716 for collagen, r\u200a=\u200a0.630 for carbon and r\u200a=\u200a0.706 for nitrogen, p\u22640.001 for all) with approximately or close to half of the variation in each explained by variation in the organic-phosphate ratio (51.2% for collagen, 39.6% for carbon, and 49.8% for nitrogen). Although the Raman screening method cannot directly quantify the extent of collagen survival, it could be of use in the selection of bone most likely to have viable protein required for reliable results from stable isotope analysis.", "keyphrases": ["raman spectroscopy", "selection", "isotopic analysis"]}
{"id": "10.1017/pab.2017.26", "title": "Evidence for stratigraphy in molluscan death assemblages preserved in seagrass beds: St. Croix, U.S. Virgin Islands", "abstract": "Abstract. \n Death assemblages that occupy the upper tens of centimeters of sediment in shallow-marine settings are often subject to extensive mixing, thereby limiting their usefulness in assessing environmentally mediated compositional changes through time in the local biota. Here, we provide evidence that dense, Thalassia-rich seagrass beds preserve a stratigraphic record of biotic variation because their dense root-rhizome mats inhibit mixing. We sampled benthic mollusk assemblages at seven localities in Thalassia-rich beds around St. Croix, USVI, collecting three separate sediment intervals of \u223c13cm each to a total depth of \u223c40 cm below the sediment-water interface, and found evidence that sedimentary intervals preserved compositional stratigraphy. Further, some localities displayed systematic, directional changes down-core. An examination of interval-to-interval changes in composition revealed that compositional variation was unique from locality to locality rather than reflecting coordinated, islandwide transitions. In general, however, relative abundances of epifaunal gastropods and small lucinid bivalves tended to decrease with depth below the sediment-water interface. Quantitative comparisons of life-to-death assemblages from each successive sedimentary interval demonstrated that the shallowest death assemblages were typically more similar to the life assemblages than were deeper assemblages, suggesting that deeper intervals provide records of earlier community states.", "keyphrases": ["stratigraphy", "death assemblage", "seagrass bed"]}
{"id": "10.1130/gsatg99a.1", "title": "Wind erosion in the Qaidam basin, central Asia: Implications for tectonics, paleoclimate, and the source of the Loess Plateau", "abstract": "Liquid water and ice are the dominant agents of erosion and sediment transport in most actively growing mountain belts. An exception is in the western Qaidam basin along the northeastern margin of the Tibetan Plateau, where wind and windblown sand have sculpted enormous yardang fields in actively folding sedimentary strata. Here, we present observations suggesting that since the late Pliocene, wind episodically (during glacial and stadial periods) removed strata from the western Qaidam basin at high rates (>0.12\u20131.1 mm/yr) and may have accelerated rates of tectonic folding. Severe wind erosion likely occurred during glacial and stadial periods when central Asia was drier and the main axis of the polar jet stream was located ~10\u00b0 closer to the equator (over the Qaidam basin), as predicted by global climate models. Reconstructed wind patterns, the estimated volume of Qaidam basin material removed by wind, and numerical models of dust transport all support the hypothesis that the Qaidam basin was a major source of dust to the Loess Plateau.", "keyphrases": ["qaidam basin", "loess plateau", "wind erosion"]}
{"id": "paleo.003714", "title": "Triassic and Jurassic palaeoclimate development in the Junggar Basin, Xinjiang, Northwest China\u2014a review and additional lithological data", "abstract": "The Junggar Basin in the Xinjiang Uygur Autonomous Region (NW China) comprises an almost continuous sequence of continental Mesozoic sediments. The basin was positioned at a latitude of about 45\u00b0N from the Permian onwards and existed almost during the entire Mesozoic. As such, it is well suited for studies on palaeoclimatic and palaeoenvironmental changes during this period as tectonic movements of the basin between different climate zones can largely be excluded. Current knowledge about Triassic and Jurassic palaeoclimate development is complemented by new lithological data from the southern part of the basin, ranging from the Late Triassic (Norian) up to the latest Jurassic (Tithonan). Preliminary palynostratigraphical data demonstrate that the base of the Middle Jurassic probably does not coincide with lithostratigraphical formation boundaries (i.e., boundary between Sangonghe and Xishanyiao Formation), but lies within the lower part of the Sangonghe Formation. Humid climates dominated during the Triassic and the Early Jurassic, with only a few drier This article is a contribution to the special issue \"Triassic-Jurassic biodiversity, ecosystems, and climate in the Junggar Basin, Xinjiang, Northwest China\" Electronic supplementary material The online version of this article", "keyphrases": ["junggar basin", "lithological data", "triassic"]}
{"id": "paleo.008427", "title": "The influence of climate on morphometric traits of fossil populations of\n Microtus arvalis\n and\n M\n .\u00a0\n agrestis\n from the Carpathian Basin, northern Hungary", "abstract": "In this study, we analysed morphometrically fossil populations of Microtus arvalis and M. agrestis from eight late Middle to Late Pleistocene archaeological and palaeontological sites in the Carpathian Basin, northern Hungary. The intra-and interspecific variations in both species can be related to climatic oscillations linked to the onset of the Eemian interglacial and the first phases of Marine Isotope Stage 5. The size of M. agrestis can be correlated with the presence/absence of relatively humid climatic and environmental conditions and of surface water resources (such as marshes and flooded areas). A possible immigration event of M. arvalis populations into the Carpathian Basin, also related to the Eemian interglacial, is also identified. \u25a1 common vole, field vole, Hungary, marine Isotope Stage 5, middle-late Pleistocene, morphometrics.", "keyphrases": ["fossil population", "carpathian basin", "northern hungary"]}
{"id": "10.1080/03115518.2016.1144385", "title": "South polar greenhouse insects (Arthropoda: Insecta: Coleoptera) from the mid-Cretaceous Tupuangi Formation, Chatham Islands, eastern Zealandia", "abstract": "Stilwell, J.D., Vitacca, J. & Mays, C., April 2016. South polar greenhouse insects (Arthropoda: Insecta: Coleoptera) from the mid-Cretaceous Tupuangi Formation, Chatham Islands, eastern Zealandia. Alcheringa 40, xxx\u2013xxx. ISSN 0311-5518 Rare insect body fossils have been discovered for the first time after 175 years of research on the Chatham Islands, eastern \u2018Zealandia\u2019. The coleopteran (beetle) insects, dated to ca 95 Ma and extracted from fine-grained, upper delta plain facies in the lower Upper Cretaceous (Cenomanian\u2013lowermost Turonian) Tupuangi Formation at Waihere Bay on the remote Pitt Island, represent the most southern, polar-latitude (ca 70\u201380\u00b0S) faunal assemblage from the Cretaceous recorded to date. Three species are represented in the insect fauna: a portion of a segmented abdomen of a probable carabid? ground beetle and two distinct coleopteran elytra, one preserved with a brilliantly iridescent carapace upon discovery, comparable with Cretaceous taxa within the Buprestidae (metallic wood borers), but identification with the Chrysomelidae (leaf beetles) or Tenebrionidae (darkling beetles) can not be discounted entirely. Another specimen has more weakly preserved greenish iridescence and has a morphology consistent with Carabidae; given the preservational deficiencies and rarity of material, the specimens are attributed to Buprestidae? genus et species indeterminate and Carabidae? genus et species indeterminate A and B, respectively. These coleopteran fossils represent the only recorded iridescence in Mesozoic invertebrates from Zealandia. Importantly, these mid-Cretaceous insects existed in South Polar forests near the height of the \u2018hothouse\u2019 phase of relatively warm, alternating intervals of full daylight in the summer months and total darkness during the winter, before eastern Zealandia diverged at ca 83 Ma from the Marie Byrd Land region of West Antarctica, as part of the final break-up of Gondwana. Jeffrey D. Stilwell* [jeffrey.stilwell@monash.edu], Jesse V. Vitacca [jesse.vitacca@gmail.com] & Chris Mays [chris.mays@monash.edu], School of Earth, Atmosphere and Environment, Monash University, Clayton VIC 3800, Australia. *Also affiliated with the Australian Museum, 6 College Street, Sydney NSW 2000, Australia.", "keyphrases": ["greenhouse insect", "arthropoda", "chatham islands"]}
{"id": "paleo.005600", "title": "A dicynodont-theropod association in the latest Triassic of Poland", "abstract": "It is generally accepted that during the Triassic the composition of tetrapod faunas underwent a series of fundamental transformations, mainly as a result of diversification of archosaurs and decline of therapsids (Benton 1994, 2004, 2006). The last herbivorous basal synapsids, dicynodonts, disappeared from the record in the early Norian of the Americas, about 220 Ma (Langer et al. 2007), being unknown from the Late Triassic of Europe. Here, we report a partially articulated skeleton and isolated bones of a giant rhino-size dicynodont in the Upper Triassic fluvial sediments at Lisowice (Lipie \u015al\u0105skie clay-pit) in southern Poland. Paleobotanical data indicate an early Rhaetian age for the fauna (Dzik et al. 2008; Nied\u017awiedzki and Sulej 2008). The dicynodont bones are associated with bones of carnivorous dinosaurs, pterosaurs, as well as capitosaur and plagiosaur amphibians. Dicynodonts were represented in the Germanic Basin throughout the Late Triassic, as proven by findings of smaller dicynodonts in older deposits in the same area, associated there with temnospondyl amphibians. It appears, thus, that the fossil record of tetrapod succession in the Late Triassic was strongly controlled by ecological factors and biased by uneven representation of particular environments. The Lisowice assemblage proves that faunas dominated by dicynodonts did not entirely disappear at least until the end of the Triassic.", "keyphrases": ["tetrapod faunas", "dicynodont", "late triassic", "lipie \u015bl\u0105skie clay-pit", "germanic basin"]}
{"id": "10.1080/08912963.2017.1351441", "title": "Palaeoecology of cave bears as evidenced by dental wear analysis: a review of methods and recent findings", "abstract": "Abstract The study of dental wear was first used years ago to infer the palaeoecology of fossil mammals and in particular their diet. Results depend predominantly on the scale of the analysis used. Analyses of dental macrowear, mesowear or microwear do not provide the same type of dietary information, be it about the seasonal, annual or lifetime diet. This contribution focuses on emblematic species, cave bears (Ursidae), in particular Ursus spelaeus spelaeus. Methods used by previous researchers to infer their dietary preferences and thus their palaeoecology are reviewed and compared. This review is complemented by an analysis of several specimens of cave bears from the Goyet cave in Belgium, using dental microwear texture analysis (DMTA), a methodology widely applied for reconstructing palaeodiets. Three main conclusions are drawn here: (1) DMTA is the method that provides the most precise palaeobiological inferences; (2) during the pre-dormancy period, cave bears show dietary flexibility; (3) dental wear alone might be not sufficient to provide a complete reconstruction of the cave bear palaeodiet.", "keyphrases": ["cave bear", "belgium", "dmta", "pre-dormancy period", "palaeoecology"]}
{"id": "10.2478/v10263-012-0014-y", "title": "An introduction to the palaeoenvironmental reconstruction of the Bathonian (Middle Jurassic) ore-bearing clays at Gnaszyn, Krak\u00f3w-Silesia Homocline, Poland", "abstract": "This paper provides introductory data for multidisciplinary studies on palaeoenvironmental reconstructions of the\u00a0Bathonian (Middle Jurassic) ore-bearing clays exposed at Gnaszyn, southern Poland. These dark-coloured fine-clastic\u00a0deposits have been studied for micropalaeontology, sedimentology and geochemistry (published in separate papers\u00a0within this volume). Brief outlines of the Middle Jurassic palaeogeography of the Polish epicontinental basin\u00a0and the geology of the Krakow-Silesia Homocline are given. A description of the ore-bearing clays succession exposed\u00a0in the clay-pit at Gnaszyn is provided, including locations of the sections studied, their ammonite biostratigraphy,\u00a0brief lithology and macrofossil distribution. The sample positions collected for micropalaeontological\u00a0and geochemical studies are specified.", "keyphrases": ["palaeoenvironmental reconstruction", "bathonian", "clay"]}
{"id": "10.1017/jpa.2015.57", "title": "First remingtonocetid archaeocete (Mammalia, Cetacea) from the middle Eocene of Egypt with implications for biogeography and locomotion in early cetacean evolution", "abstract": "Abstract. Remingtonocetidae are Eocene archaeocetes that represent a unique experiment in cetacean evolution. They possess long narrow skulls, long necks, fused sacra, and robust hind limbs. Previously described remingtonocetids are known from middle Eocene Lutetian strata in Pakistan and India. Here we describe a new remingtonocetid, Rayanistes afer, n. gen. n. sp., recovered from a middle to late Lutetian interval of the Midawara Formation in Egypt. The holotype preserves a sacrum with four vertebral centra; several lumbar and caudal vertebrae; an innominate with a complete ilium, ischium, and acetabulum; and a nearly complete femur. The ilium and ischium of Rayanistes are bladelike, rising sharply from the body of the innominate anterior and posterior to the acetabulum, and the acetabular notch is narrow. These features are diagnostic of Remingtonocetidae, but their development also shows that Rayanistes had a specialized mode of locomotion. The expanded ischium is larger than that of any other archaeocete, supporting musculature for powerful retraction of the hind limbs during swimming. Posteriorly angled neural spines on lumbar vertebrae and other features indicate increased passive flexibility of the lumbus. Rayanistes probably used its enhanced lumbar flexibility to increase the length of the power stroke during pelvic paddling. Recovery of a remingtonocetid in Egypt broadens the distribution of Remingtonocetidae and shows that protocetids were not the only semiaquatic archaeocetes capable of dispersal across the southern Tethys Sea.", "keyphrases": ["middle eocene", "locomotion", "cetacean evolution"]}
{"id": "paleo.006706", "title": "An Unusual New Theropod with a Didactyl Manus from the Upper Cretaceous of Patagonia, Argentina", "abstract": "Background Late Cretaceous terrestrial strata of the Neuqu\u00e9n Basin, northern Patagonia, Argentina have yielded a rich fauna of dinosaurs and other vertebrates. The diversity of saurischian dinosaurs is particularly high, especially in the late Cenomanian-early Turonian Huincul Formation, which has yielded specimens of rebacchisaurid and titanosaurian sauropods, and abelisaurid and carcharodontosaurid theropods. Continued sampling is adding to the known vertebrate diversity of this unit. Methodology/ Principal Findings A new, partially articulated mid-sized theropod was found in rocks from the Huincul Formation. It exhibits a unique combination of traits that distinguish it from other known theropods justifying erection of a new taxon, Gualicho shinyae gen. et sp. nov. Gualicho possesses a didactyl manus with the third digit reduced to a metacarpal splint reminiscent of tyrannosaurids, but both phylogenetic and multivariate analyses indicate that didactyly is convergent in these groups. Derived characters of the scapula, femur, and fibula supports the new theropod as the sister taxon of the nearly coeval African theropod Deltadromeus and as a neovenatorid carcharodontosaurian. A number of these features are independently present in ceratosaurs, and Gualicho exhibits an unusual mosaic of ceratosaurian and tetanuran synapomorphies distributed throughout the skeleton. Conclusions/ Significance Gualicho shinyae gen. et sp. nov. increases the known theropod diversity of the Huincul Formation and also represents the first likely neovenatorid from this unit. It is the most basal tetatanuran to exhibit common patterns of digit III reduction that evolved independently in a number of other tetanuran lineages. A close relationship with Deltadromaeus from the Kem Kem beds of Niger adds to the already considerable biogeographic similarity between the Huincul Formation and coeval rock units in North Africa.", "keyphrases": ["new theropod", "didactyl manus", "patagonia"]}
{"id": "paleo.001967", "title": "Silurian bolbozoids and cypridinids (Myodocopa) from Europe: pioneer pelagic ostracods", "abstract": "Abstract:\u2002 Bolbozoid and cypridinid myodocope ostracods from France, the Czech Republic and Sardinia consist of four genera (one new: Silurocypridina) and at least ten species (eight new: Bolbozoe acuta, B. rugosa, B. parvafraga, Parabolbozoe armoricana, Silurocypridina retroreticulata, S. variostriata, S. calva and Calocaria robusta). They have a functional design, palaeogeographical distribution, depositional setting and faunal associates that suggest that they were swimmers in the water column, living in dim light, relatively deep environments, above near bottom dysoxic/anoxic conditions. These myodocope faunas include some possible pelagic species sensu stricto, with widespread palaeogeographical (transoceanic) distribution, and some species that occupied hyperbenthic niches and were capable of making short incursions to the sediment to scavenge on carrion. These data support the model that Silurian myodocopes were pioneer pelagic ostracods.", "keyphrases": ["bolbozoid", "pelagic ostracod", "silurian myodocope"]}
{"id": "10.1130/b25743.1", "title": "Source of Oligocene to Pliocene sedimentary rocks in the Linxia basin in northeastern Tibet from Nd isotopes: Implications for tectonic forcing of climate", "abstract": "We used Nd isotopes and trace element data to determine the provenance of sedimentary rocks in the Linxia basin, northeastern Tibet, whose Oligocene through Pliocene sedimentation history has been interpreted to refl ect deposition in a fl exural basin associated with contractional deformation along the northeastern margin of the Tibetan Plateau. Paleozoic\u2010early Mesozoic metasedimentary source rocks from the KunlunQaidam and Songpan-Ganzi terranes have e Nd values between \u221211.8 and \u221216.1, whereas Paleozoic and Mesozoic plutonic source rocks that intrude the metasedimentary rocks have more positive e Nd values between \u22123.6 and \u221211.2. Cretaceous sedimentary source rocks display e Nd values of \u22129.7 and \u20109.9 in the Maxian Shan, north of the Linxia basin, and \u201015.3 in the plateau margin south of the basin. With e Nd values that range between \u22128.4 and \u221210.4 before ca. 15 Ma, and \u22126.2 and \u221211.8 after ca. 14 Ma, sedimentary rocks of the Linxia basin are less negative than metasedimentary rocks, which are dominant source rocks within the margin of the Tibetan Plateau today. The relatively positive e Nd values of Linxia basin sedimentary rocks could refl ect several possible sources, including (1) a mixture of plutonic and metasedimentary rocks within the northeastern margin of Tibet, (2) Cretaceous sedimentary rocks derived from the north, or (3) loess derived from central Asian deserts. A mass balance calculation indicates that plutonic rocks are not volumetrically signifi cant enough to generate the e Nd values observed in Linxia basin sedimentary rocks through mixing of plutonic and metasedimentary sources. Rare earth element patterns suggest that Cretaceous rocks were not a dominant source of sediment. The Nd isotopic composition and rare earth element pattern of Quaternary loess are similar to older deposits in the Linxia basin and refl ect loess deposited elsewhere in the Loess plateau and the North Pacifi c (e Nd = \u22128.6 to \u201010.5). In addition, the modern Daxia River, which drains the margin of the plateau today, transports clay and silt with e Nd values of \u201010.5 to \u201010.8 despite the river\u2019s source in more negative metasedimentary rocks of the Kunlun-Qaidam and Songpan-Ganzi terranes, which indicates that the modern fi ne-grained sedimentary budget is dominated by recent loess deposits. Considering the slow sedimentation rates in the Linxia basin, it is likely that loess sources have contributed a signifi cant volume of fi grained sediment to this basin throughout its history. An increase in the range of e Nd values at ca. 14 Ma in the Linxia basin may refl ect increased unroofi ng of the northeastern margin of Tibet, which slightly preceded a change in climate between ca. 13 and 12 Ma in the Linxia basin. A 1.5\u2030 increase in baseline \u03b4 18 O values of lacustrine carbonates has been interpreted as the result of reorganization of atmospheric circulation and an increase in aridity on the northeastern margin of the Tibetan Plateau, perhaps associated with the plateau having achieved an elevation suffi cient to block moisture from the Indian Ocean and/or Pacifi c Ocean. Similar timing of exhumation and climate change suggests that northeastward and eastward propagation of the plateau margin was responsible for the middle Miocene climate change observed in the Linxia basin.", "keyphrases": ["oligocene", "sedimentary rock", "northeastern tibet"]}
{"id": "paleo.003573", "title": "Geographic Information Systems technology as a morphometric tool for quantifying morphological variation in an ammonoid clade", "abstract": "Ammonoids are known for their intraspecific and interspecific morphological variation through ontogeny, particularly in shell shape and ornamentation. Many features covary and individual elements are difficult to homologize, which make qualitative descriptions and widely-used morphometric tools inappropriate for quantifying these complex morphologies. However, spatial analyses conducted in a geographic information systems (GIS) environment allow for quantification and visualization of global shell form. Here, we present a GIS-based methodology in which the variation of shell features is assessed to evaluate evolutionary patterns in an ammonoid clade from the Late Cretaceous Western Interior Seaway of North America. We investigate the ancestral and more variable scaphitid heteromorph ammonoid Hoploscaphites spedeni and its less variable descendant H. nebrascensis. We created three-dimensional (3D) digital models of the fossil shells' lateral surfaces using photogrammetric software and imported the reconstructions into a GIS environment. We used the number of discrete aspect patches and the surface-to-planimetric (3D to 2D) area ratios of the lateral surface as terrain roughness indices. These 3D spatial analyses demonstrate the overlapping morphological ranges of H. spedeni and H. nebrascensis in ornamentation despite differences in shell compression. Additionally, the target for evolutionary change in this clade resides in the macroconch body chamber, which becomes less variable through development from H. spedeni to subsequent H. nebrascensis in macroconchs; however, microconchs retain the ancestral variation through ontogeny. These geospatial analyses not only successfully quantified variation in complex morphologies, but also demonstrated the versatility of this method to address questions related to ontogeny and phylogeny.", "keyphrases": ["tool", "morphological variation", "ammonoid clade"]}
{"id": "10.2110/jsr.2018.59", "title": "Active Ooid Growth Driven By Sediment Transport in a High-Energy Shoal, Little Ambergris Cay, Turks and Caicos Islands", "abstract": "Ooids are a common component of carbonate successions of all ages and present significant potential as paleoenvironmental proxies, if the mechanisms that control their formation and growth can be understood quantitatively. There are a number of hypotheses about the controls on ooid growth, each offering different ideas on where and how ooids accrete and what role, if any, sediment transport and abrasion might play. These hypotheses have not been well tested in the field, largely due to the inherent challenges of tracking individual grains over long timescales. This study presents a detailed field test of ooid-growth hypotheses on Little Ambergris Cay in the Turks and Caicos Islands, British Overseas Territories. This field site is characterized by westward net sediment transport from waves driven by persistent easterly trade winds. This configuration makes it possible to track changes in ooid properties along their transport path as a proxy for changes in time. Ooid size, shape, and radiocarbon age were compared along this path to determine in which environments ooids are growing or abrading. Ooid surface textures, petrographic fabrics, stable-isotope compositions (\u03b4^(13)C, \u03b4^(18)O, and \u03b4^(34)S), lipid geochemistry, and genetic data were compared to characterize mechanisms of precipitation and degradation and to determine the relative contributions of abiotic (e.g., abiotic precipitation, physical abrasion) and biologically influenced processes (e.g., biologically mediated precipitation, fabric destruction through microbial microboring and micritization) to grain size and character. A convergence of evidence shows that active ooid growth occurs along the transport path in a high-energy shoal environment characterized by frequent suspended-load transport: median ooid size increases by more than 100 \u03bcm and bulk radiocarbon ages decrease by 360 yr westward along the \u223c 20 km length of the shoal crest. Lipid and 16S rRNA data highlight a spatial disconnect between the environments with the most extensive biofilm colonization and environments with active ooid growth. Stable-isotope compositions are indistinguishable among samples, and are consistent with abiotic precipitation of aragonite from seawater. Westward increases in ooid sphericity and the abundance of well-polished ooids illustrate that ooids experience subequal amounts of growth and abrasion\u2014in favor of net growth\u2014as they are transported along the shoal crest. Overall, these results demonstrate that, in the Ambergris system, the mechanism of ooid growth is dominantly abiotic and the loci of ooid growth is determined by both carbonate saturation and sediment transport mode. Microbes play a largely destructive, rather than constructive, role in ooid size and fabric.", "keyphrases": ["ooid growth", "sediment transport", "caicos islands"]}
{"id": "10.1111/j.1523-1739.2012.01920.x", "title": "Integrating Paleobiology, Archeology, and History to Inform Biological Conservation", "abstract": "The search for novel approaches to establishing ecological baselines (reference conditions) is constrained by the fact that most ecological studies span the past few decades, at most, and investigate ecosystems that have been substantially altered by human activities for decades, centuries, or more. Paleobiology, archeology, and history provide historical ecological context for biological conservation, remediation, and restoration. We argue that linking historical ecology explicitly with conservation can help unify related disciplines of conservation paleobiology, conservation archeobiology, and environmental history. Differences in the spatial and temporal resolution and extent (scale) of prehistoric, historic, and modern ecological data remain obstacles to integrating historical ecology and conservation biology, but the prolonged temporal extents of historical ecological data can help establish more complete baselines for restoration, document a historical range of ecological variability, and assist in determining desired future conditions. We used the eastern oyster (Crassostrea virginica) fishery of the Chesapeake Bay (U.S.A.) to demonstrate the utility of historical ecological data for elucidating oyster conservation and the need for an approach to conservation that transcends disciplinary boundaries. Historical ecological studies from the Chesapeake have documented dramatic declines (as much as 99%) in oyster abundance since the early to mid\u20101800s, changes in oyster size in response to different nutrient levels from the sixteenth to nineteenth centuries, and substantial reductions in oyster accretion rates (from 10 mm/year to effectively 0 mm/year) from the Late Holocene to modern times. Better integration of different historical ecological data sets and increased collaboration between paleobiologists, geologists, archeologists, environmental historians, and ecologists to create standardized research designs and methodologies will help unify prehistoric, historic, and modern time perspectives on biological conservation.", "keyphrases": ["paleobiology", "archeology", "biological conservation", "ecological study", "need"]}
{"id": "10.1080/02724634.2015.983524", "title": "A New Fossil Actinistian from the Early Jurassic of Chile and Its Bearing on the Phylogeny of Actinistia", "abstract": "ABSTRACT \n We present the description and taxonomic reassignment of a new genus and species, Atacamaia solitaria, gen. et sp. nov., from Lower Jurassic strata of northern Chile, South America. The fish was previously reported as a new genus of Mawsoniidae, based on one unprepared specimen. The fish is characterized by a combination of numerous intriguing characters, such as the presence of a broad parietal bone partially covered laterally by a series of a few large supraorbital bones, a series of sclerotic bones, a lachrymojugal expanded anteriorly and markedly angled, and a metapterygoid with a well-developed ventral process that is ventral to the dorsal margin of the pterygoid plate. Addition of Atacamaia to previously published matrices produces unexpected collapses of certain nodes in the currently accepted phylogenetic hypothesis of Actinistia, creating many polytomies in the consensus tree. Our cladistic analysis suggests that Atacamaia, gen. et sp. nov., Axelia, and Wimania are closely related and together with Piveteauia, Guizhoucoelacanthus, and Whiteia are members of the order Coelacanthiformes. Based on previous analyses and our results, we recognize this grouping as the family Whiteiidae. Members of Whiteiidae are Triassic forms, except Atacamaia solitaria, gen. et sp. nov., from the Early Jurassic. The new fossil actinistian represents the youngest member of the family and the first discovered on the Paleopacific side of Gondwana; all other members are from China, Madagascar, and Spitsbergen. After comparison of previous hypotheses, we review the higher level taxonomy of Actinistia concerning the monophyly of Coelacanthiformes, Latimeroidei, Mawsoniidae, and Latimeriidae and propose a family diagnosis for Whiteiidae.", "keyphrases": ["new fossil actinistian", "early jurassic", "actinistia"]}
{"id": "10.1002/ajpa.20447", "title": "Spondylolysis, spondylolisthesis, and lumbo-sacral morphology in a medieval English skeletal population.", "abstract": "The prevalence of spondylolysis and spondylolisthesis was studied in an adult skeletal series from a rural English medieval archaeological site. Attempts were made to evaluate the association of three aspects of lumbo-sacral skeletal morphology (pelvic incidence (a measure of the anterior inclination of the sacral table), lumbar transverse process width, and the presence of lumbo-sacral spina bifida occulta) with spondylolysis and spondylolisthesis. Results indicated a high prevalence of spondylolysis compared with a modern reference population, but few cases of spondylolisthesis were identified. Analysis of prevalence with respect to age suggests that in the study population, pars interarticularis defects generally formed late in the growth period or early in adult life. The study group showed a high mean pelvic incidence compared with modern Western Europeans, indicating a more steeply inclined sacral table, which may have elevated the risk of developing pars interarticularis defects. However, no statistically valid association could be demonstrated between the presence/absence of spondylolysis and pelvic incidence in the study material. There was no evidence for a link between lumbar transverse process index or lumbo-sacral spina bifida occulta and spondylolysis/spondylolisthesis. It is concluded that the potential role of lumbo-sacral morphology, as well as of activity regimes, should be considered when interpreting spondylolysis in paleopathological studies. If the frequency of spondylolysis is to some extent an indicator of past activity regimes, it may reflect lifestyle in younger individuals rather than in mature adults. Further work investigating the link between spondylolysis and lumbo-sacral morphological variables in premodern populations would be of value.", "keyphrases": ["spondylolisthesis", "lumbo-sacral morphology", "skeletal series"]}
{"id": "10.1144/jgs2015-050", "title": "Palaeoenvironment, palaeoclimate and age of the Brassington Formation (Miocene) of Derbyshire, UK", "abstract": "The Brassington Formation is the most extensive Miocene sedimentary succession onshore in the UK. Because of its unique position at the margin of NW Europe, the pollen from this lithostratigraphical unit provides evidence on the development of vegetation affected by North Atlantic currents and hypothesized atmospheric circulation changes during the Middle to Late Miocene climate cooling. Palynostratigraphy suggests that the uppermost Kenslow Member of the Brassington Formation is not coeval. Previously, all occurrences of the Kenslow Member were assumed to be contemporary. The oldest pollen assemblage is from the more southern Bees Nest Pit, which represents a subtropical conifer-dominated forest of late Serravallian age (c. 12\u2009Ma). A younger assemblage was observed from the more northern Kenslow Top Pit; this indicates that a subtropical mixed forest was present during the early Tortonian (11.6\u20139\u2009Ma). The shift from a conifer-dominated to a mixed forest was related to precipitation. Although the total precipitation did not change between the two assemblages, the younger assemblage had more uniform rainfall throughout the year. The diachronous nature of the Kenslow Member means that the depositional model of the Brassington Formation needs revising, and this will have implications for Neogene to recent uplift of the southern Pennines. Supplementary material: All valid formally defined palynomorph taxa below the generic level that are mentioned in this paper, with full author citations, are available at http://www.geolsoc.org.uk/SUP18889.", "keyphrases": ["brassington formation", "miocene", "north atlantic current", "kenslow top pit"]}
{"id": "10.1017/S1477201907002386", "title": "The origin and early evolution of the Osteostraci (Vertebrata): A phylogeny for the Thyestiida", "abstract": "Synopsis The Osteostraci are currently regarded as the sister taxon to jawed vertebrates and, as such, osteostracan phylogeny, notably their hypothetical ancestral morphotype, has far reaching ramifications for early vertebrate evolution. The polarity of the group and the monophyly and interrelationships of the proposed constituent clades have not been tested. Here a new phylogeny is proposed for the Thyestiida, the most controversial and informative of the five main orders of Osteostraci. A comprehensive global parsimony approach is applied for the first time. The monophyly of the group, including genera of suspected thyestiid affinities, is firmly demonstrated, as is the monophyly of some constituent groups such as the Siberian Tannuaspidinae. The phylogeny supports the proposals of Janvier (1985a\u2010c) and is inconsistent with previous \u2018Tremataspis\u2010basal\u2019 models of Osteostracan evolution. Application of the phylogeny to the stratigraphical record demonstrates an early evolution and origin for the Osteostraci and indicates a missing fossil record for the group in the Llandovery, strongly related to facies bias.", "keyphrases": ["osteostraci", "phylogeny", "thyestiida"]}
{"id": "10.1073/pnas.96.9.5111", "title": "1,2,3 = 2,3,4: a solution to the problem of the homology of the digits in the avian hand.", "abstract": "Persistent contradictions in well supported empirical findings usually point to important scientific problems and may even lead to exciting new insights. One of the most enduring problems in evolutionary biology is the apparent conflict between paleontological and embryological evidence regarding the homology of the digits in the avian hand (1, 2). We propose that this problem highlights an important feature of morphological change: namely, the possible dissociation between the developmental origin of a particular repeated element and its subsequent individualization into a fully functional character. We argue that, although comparative embryological evidence correctly identifies the homology of the primordial condensations in avians as CII, CIII, and CIV, subsequent anatomical differentiation reflects a frame shift in the developmental identities of the avian digit anlagen in later ontogeny such that CII becomes DI, CIII becomes DII, and CIV becomes DIII.", "keyphrases": ["homology", "digit", "avian hand"]}
{"id": "10.1080/14772019.2016.1167786", "title": "Gabaleryon, a new genus of widespread early Toarcian polychelidan lobsters", "abstract": "Polychelidan lobsters are decapod crustaceans with a unique anatomy: a dorsoventrally flattened carapace, four to five pairs of chelate appendages and a completely reduced rostrum. These crustaceans, like most other malacostracans, are mostly preserved in outcrops in which exceptional preservation occurs, Fossil-Konservat-Lagerst\u00e4tten. Unfortunately, Lagerst\u00e4tten are rare, and therefore disjointed both geographically and stratigraphically. This study focuses on a new genus of polychelidan lobster, Gabaleryon gen. nov., with the description of two new Toarcian species, Gabaleryon coquelae sp. nov. from France and G. garassinoi sp. nov. from Italy. The long-standing question of the generic assignment of Eryon moorei (Toarcian, UK) is resolved and the species is ascribed to Gabaleryon. The occurrences of these three species and a fourth, Gabaleryon sp. 1 (Toarcian, Germany), provide a first palaeobiogeographical indication that the Fossil-Lagerst\u00e4tten in which they occur were linked during Toarcian times. The occurrence of a possible fifth species of Gabaleryon in the late Bajocian\u2013early Bathonian of France may extend the stratigraphical distribution of the new genus. Finally, these new species increase our knowledge of fossil polychelidans and place the Toarcian as their second peak of palaeobiodiversity, after that at the Kimmeridgian\u2013Tithonian boundary. http://zoobank.org/urn:lsid:zoobank.org:pub:073513BD-A0D8-4A5B-B9DE-1C61781077DC", "keyphrases": ["new genus", "polychelidan lobster", "gabaleryon"]}
{"id": "paleo.001692", "title": "Morphological disparity and developmental patterning: contribution of phacopid trilobites", "abstract": "In trilobites as in many others extinct organisms, our understanding of the mechanisms of evolution is based on morphological and ontogenetic features. Data from ontogenetic development are essential to provide an insight into the origins of evolutionary changes. In phacopid trilobites, detailed studies of ontogenetic series have been achieved using quantitative methods. A comparison of ontogenetic trajectories of closely related species has been conducted to understand how the both morphological disparity and developmental patterning of different ontogenetic stages were structured and to determine how the environmental or developmental constraints influenced morphological changes in trilobites. Study of such morphological disparity in developmental evolution requires knowledge of morphological features and timing and rate of development among closely related species. At a macroevolutionary scale, such quantitative studies should allow us (1) to determine the impact of individual ontogenies on morphological diversification and (2) to identify the evolutionary patterns in Phacopidae during 100 Ma of existence.", "keyphrases": ["developmental patterning", "phacopid trilobite", "trilobite"]}
{"id": "10.32774/FosRepPal.2020.0614", "title": "An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study", "abstract": "Corresponding autor\u2019s contact: marco.viaretti@studenti.unimi.it How to cite: Viaretti et al. (2020). An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study. Fossilia, Volume 2020: 53-55. https://doi.org/10.32774/ FosRepPal.2020.0614 Fossilia Reports in Palaeontology An exceptionally well-preserved scorpion from the Besano Formation (Monte San Giorgio, Middle Triassic, Southern Alps): preliminary study", "keyphrases": ["well-preserved scorpion", "middle triassic", "southern alps"]}
{"id": "10.1017/S0094837300000324", "title": "Competition, clade replacement, and a history of cyclostome and cheilostome bryozoan diversity", "abstract": "One of the striking yet scarcely documented episodes of clade replacement in the post-Paleozoic fossil record is the decline of cyclostome Bryozoa and the corresponding, rapid diversification of cheilostome Bryozoa. These clades are closely associated morphologically and phylogenetically, and their ecological similarities have previously led to the inference that competition was a primary cause of the overt pattern of replacement. Alternatively, previous compilations of bryozoan families and genera have implied that extinctions at the Cretaceous/Tertiary boundary differentially affected cyclostomes, and thus were also an important factor in the transition. We first evaluated the ecological context for competition between the two clades, then updated and reexamined the history of absolute family diversity for bryozoans in consecutive geologic stages from Jurassic to Recent. The resulting trends echo the patterns shown in earlier family level compilations, but indicate a slight shift in the frequency of cheilostome family originations from Late Cretaceous to early Paleogene. The relative fall in cyclostome family diversity at the Cretaceous/Tertiary boundary is significantly less than shown in earlier genus level compilations. We then assessed these various compilations of absolute diversity by analyzing species counts and percentages in 728 fossil assemblages, primarily from North America and Europe, over the same time interval. Cyclostome species overwhelmingly dominate assemblages from Jurassic through Cenomanian, then decline significantly in average percentage dominance through the Campanian. Cheilostomes are predominant in Campanian and later assemblages. Cyclostome species percentages do decrease overall through the Tertiary, but this decrease is small and non-uniform, varying around 30%, with a sharp drop in the Late Neogene. Our within-assemblage results indicate that as cheilostomes radiate, their mean species diversity, maximum diversity, and variance all increase, thereby accounting for much of the decline in average percentage of cyclostomes within assemblages. While this result does not exclude a role for competition, an hypothesis of relative decline in cyclostome species richness based on competitive extinction alone seems unlikely. Further, despite decreases in absolute species counts following end-Cretaceous extinctions, within-assemblage percentages of cheilostome or cyclostome species show only slight change relative to one another. Comparison of these and earlier diversity compilations indicates that the dynamics of bryozoan clade replacement may be perceived differently at different ecologic scales or taxonomic ranks.", "keyphrases": ["clade replacement", "cyclostome", "cheilostome", "bryozoan", "competition"]}
{"id": "10.1002/2015PA002818", "title": "Global carbon cycle perturbation across the Eocene-Oligocene climate transition", "abstract": "The Eocene-Oligocene transition (EOT), ~34?Ma, marks a tipping point in the long-term Cenozoic greenhouse to icehouse climate transition. Paleorecords reveal stepwise rapid cooling and ice growth across the EOT tightly coupled to a transient benthic ?13C excursion and a major and permanent deepening of the carbonate compensation depth (CCD). Based on biogeochemical box modeling, Merico et al. (2008) suggested that a combination of (1) glacioeustatic sea level fall-induced shelf-basin carbonate burial fractionation and (2) shelf carbonate weathering can account for the carbon cycle perturbation, but this finding has been questioned. Alternative proposed mechanisms include increased ocean ventilation, decreased carbonate burial, increased organic carbon burial, increased silicate weathering, and increased ocean calcium concentration. Here we use an improved version of the biogeochemical box model of Merico et al. (2008) to reevaluate these competing hypotheses and an additional mechanism, the expansion of \u201ccarbon capacitors\u201d such as permafrost and peatlands. We find that changes in calcium concentration, silicate weathering, and carbonate or organic carbon burial each yield a response that is fundamentally at odds with the form and/or sign of the paleorecords. Shelf-basin carbonate burial fractionation (CCD change), plus shelf carbonate weathering, sequestration of 12C-enriched carbon into carbon capacitors, and possibly increased ocean ventilation (?13C excursion), offers the best fit to the paleorecords. Further work is needed to understand why the EOT carbon cycle perturbation is so unique when the forcing mechanisms hypothesized to be responsible (cooling and ice growth) are not peculiar to this event.", "keyphrases": ["carbon cycle perturbation", "climate transition", "biogeochemical box model"]}
{"id": "10.1098/rspb.2009.0806", "title": "A new proposal concerning the botanical origin of Baltic amber", "abstract": "Baltic amber constitutes the largest known deposit of fossil plant resin and the richest repository of fossil insects of any age. Despite a remarkable legacy of archaeological, geochemical and palaeobiological investigation, the botanical origin of this exceptional resource remains controversial. Here, we use taxonomically explicit applications of solid-state Fourier-transform infrared (FTIR) microspectroscopy, coupled with multivariate clustering and palaeobotanical observations, to propose that conifers of the family Sciadopityaceae, closely allied to the sole extant representative, Sciadopitys verticillata, were involved in the genesis of Baltic amber. The fidelity of FTIR-based chemotaxonomic inferences is upheld by modern\u2013fossil comparisons of resins from additional conifer families and genera (Cupressaceae: Metasequoia; Pinaceae: Pinus and Pseudolarix). Our conclusions challenge hypotheses advocating members of either of the families Araucariaceae or Pinaceae as the primary amber-producing trees and correlate favourably with the progressive demise of subtropical forest biomes from northern Europe as palaeotemperatures cooled following the Eocene climate optimum.", "keyphrases": ["botanical origin", "baltic amber", "family araucariaceae", "tree", "amber deposit"]}
{"id": "10.1371/journal.pone.0175253", "title": "Supplementary cranial description of the types of Edmontosaurus regalis (Ornithischia: Hadrosauridae), with comments on the phylogenetics and biogeography of Hadrosaurinae", "abstract": "The cranial anatomy of the flat-skulled hadrosaurine Edmontosaurus regalis (Ornithischia: Hadrosauridae) is extensively described here, based on the holotype and paratype collected from the middle part of the Horseshoe Canyon Formation in southern Alberta. Focus is given to previously undocumented features of ontogenetic and phylogenetic importance. This description facilitates overall osteological comparisons between E. regalis and other hadrosaurids (especially E. annectens), and revises the diagnosis of E. regalis, to which a new autapomorphy (the dorsal half of the jugal anterior process bearing a sharp posterolateral projection into the orbit) is added. We consider the recently named Ugrunaaluk kuukpikensis from the upper Campanian/lower Maastrichtian of Alaska a nomen dubium, and conservatively regard the Alaskan material as belonging to Edmontosaurus sp.. A phylogenetic analysis of Hadrosauroidea using maximum parsimony further corroborates the sister-taxon relationship between E. regalis and E. annectens. In the strict consensus tree, Hadrosaurus foulkii occurs firmly within the clade comprising all non-lambeosaurine hadrosaurids, supporting the taxonomic scheme that divides Hadrosauridae into Hadrosaurinae and Lambeosaurinae. Within Edmontosaurini, Kerberosaurus is posited as the sister taxon to the clade of Shantungosaurus + Edmontosaurus. The biogeographic reconstruction of Hadrosaurinae in light of the time-calibrated cladogram and probability calculation of ancestral areas for all internal nodes reveals a significantly high probability for the North American origin of the clade. However, the Laramidia\u2013Appalachia dispersals around the Santonian\u2013Campanian boundary, inferred from the biogeographic scenario for the North American origin of Hadrosaurinae, are in conflict with currently accepted paleogeographic models. By contrast, the Asian origin of Hadrosaurinae with its relatively low probability resulting from the biogeographic analysis is worth seriously considering, despite the lack of fossil material from the Santonian and lower Campanian of Asia. Extra fossil collecting in appropriate geographic locations and stratigraphic intervals of Asia and Europe will help to clarify the biogeographic dynamics of hadrosaurine dinosaurs in the near future.", "keyphrases": ["edmontosaurus regalis", "ornithischia", "hadrosauridae"]}
{"id": "10.1666/06053.1", "title": "Ontogeny in the fossil record: diversification of body plans and the evolution of \u201caberrant\u201d symmetry in Paleozoic echinoderms", "abstract": "Abstract Echinoderms have long been characterized by the presence of ambulacra that exhibit pentaradiate symmetry and define five primary body axes. In reality, truly pentaradial ambulacral symmetry is a condition derived only once in the evolutionary history of echinoderms and is restricted to eleutherozoans, the clade that contains most living echinoderm species. In contrast, early echinoderms have a bilaterally symmetrical 2\u20131\u20132 arrangement, with three ambulacra radiating from the mouth. Branching of the two side ambulacra during ontogeny produces the five adult rays. During the Cambrian Explosion and Ordovician Radiation, some 30 clades of echinoderms evolved, many of which have aberrant ambulacral systems with one to four rays. Unfortunately, no underlying model has emerged that explains ambulacral homologies among disparate forms. Here we show that most Paleozoic echinoderms are characterized by uniquely identifiable ambulacra that develop in three distinct postlarval stages. Nearly all \u201caberrant\u201d echinoderm morphologies can be explained by the paedomorphic ambulacra reduction (PAR) model through the loss of some combination of these growth stages during ontogeny. Superficially similar patterns of ambulacral reduction in distantly related clades have resulted from the parallel loss of homologous ambulacra during ontogeny. Pseudo-fivefold symmetry seen in Blastoidea and the true fivefold symmetry seen in Eleutherozoa result from great reduction and total loss, respectively, of the 2\u2013 1\u20132 symmetry early in ontogeny. These ambulacral variations suggest that both developmental and ecological constraints affect the evolution of novel echinoderm body plans.", "keyphrases": ["body plan", "paleozoic echinoderm", "ontogeny"]}
{"id": "10.1029/2020PA004020", "title": "Late Pleistocene Carbon Cycle Revisited by Considering Solid Earth Processes", "abstract": "The importance of volcanic CO2 release, continental weathering, and coral reef growth on the global carbon cycle has been highlighted by several different studies. Based on these independent approaches, we here revisit the last 800\u2009kyr with the box model BICYCLE, which has been extended to be able to address these solid Earth contributions to the carbon cycle. We show that the volcanic outgassing of CO2 as a function of sea level change from mid\u2010ocean ridges and hot spot island volcanoes cannot be the generic process that leads during phases of falling obliquity to a sea level\u2010CO2 decoupling as has been suggested before. The combined contribution from continental and marine volcanism, if both lagging sea level change by 4\u2009kyr, might have added up to 13\u2009ppm to the glacial/interglacial CO2 rise. Coral reef growth as suggested by an independent model is during glacial terminations about an order of magnitude too high to be reconciled with meaningful carbon cycle dynamics. Global riverine input of bicarbonate caused by silicate and carbonate weathering is suggested to have been stable over Termination I. However, if weathering fluxes are changed by up to 50% in sensitivity experiments, the corresponding bicarbonate input might contribute less than 20 ppm to the deglacial atmospheric CO2 rise. The overall agreement of results with the new process\u2010based sediment module and the previously applied time\u2010delayed response function to mimic carbonate compensation gives confidence in the results obtained in previous applications of the BICYCLE model without solid Earth processes.", "keyphrases": ["solid earth process", "weathering", "global carbon cycle", "riverine input", "bicarbonate"]}
{"id": "paleo.002182", "title": "The Vicissicaudata revisited \u2013 insights from a new aglaspidid arthropod with caudal appendages from the Furongian of China", "abstract": "Cambrian marine ecosystems were dominated by arthropods, and more specifically artiopods. Aglaspidids represent an atypical group amongst them, not the least because they evolved and rapidly diversified during the late Cambrian, a time interval between the two diversification events of the Early Palaeozoic. Recent phylogenetic analyses have retrieved aglaspidids within the Vicissicaudata, a potentially important, but difficult to define clade of artiopods. Here we describe a new aglaspidid from the Furongian Guole Konservat-Lagerst\u00e4tte of South China. This taxon displays a pretelsonic segment bearing non-walking appendages, features as-yet known in all vicissicaudatans, but aglaspidids. A new comprehensive phylogenetic analysis provides strong support for the legitimacy of a monophyletic clade Vicissicaudata, and demonstrates the pertinence of new characters to define Aglaspidida. It also motivates important changes to the systematics of the phylum, including the elevation of Artiopoda to the rank of subphylum, and the establishment of a new superclass Vicissicaudata and a new aglaspidid family Tremaglaspididae. Two diversification pulses can be recognized in the early history of artiopods \u2013 one in the early Cambrian (trilobitomorphs) and the other in the late Cambrian (vicissicaudatans). The discrepancy between this pattern and that traditionally depicted for marine invertebrates in the Early Palaeozoic is discussed.", "keyphrases": ["appendage", "phylogenetic analysis", "aglaspidida"]}
{"id": "paleo.007626", "title": "The Huehuetla quarry, a Turonian deposit of marine vertebrates in the Sierra Norte of Puebla, central Mexico", "abstract": "The Huehuetla quarry is a new fossiliferous site located near the town of the same name, into the region of Sierra Norte, northern Puebla, Mexico. This work represents the formal beginning of paleontological research on this site. This quarry occupies an area of about one hectare that is scarcely exploited with commercial purposes. The rocks rarely extracted in this site are slabs of nice jet-black carbonated shales with microscopic crystals of pyrite; which also are resistant, oily and stinky. The fossils recovered in these slabs belong to different marine vertebrate taxa, which include complete and articulated specimens as well as isolated bones. When it is preserved, the calcium phosphate of these bones is softened and filled with large calcite and pyrite crystals. Taxa represented in Huehuetla quarry constitute a peculiar assemblage that includes Nursallia aff. tethysensis, Tselfatia formosa, Goulmimichthys roberti, Hastichthys, indeterminate species of Enchodus and Clupeidae, as well as an indeterminate mosasaur. This is the first report of the pycnodontid N. tethysensis and of the dercetid Hastichthys fish all over America. This work provides evidence supporting the taxonomical validity of the species G. roberti. Based on its fossil content and lithology, it is determined that the fossil bearing strata of the Huehuetla quarry are part of the Turonian marine deposits of the Agua Nueva Formation. Jes\u00fas Alvarado-Ortega. Instituto de Geolog\u00eda, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Circuito de la Investigaci\u00f3n S/N, Ciudad Universitaria, Delegaci\u00f3n Coyoac\u00e1n, Ciudad de M\u00e9xico 04510, M\u00e9xico. alvarado@geologia.unam.mx Kleyton Magno Cantalice Severiano. Instituto de Geolog\u00eda, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Circuito de la Investigaci\u00f3n S/N, Ciudad Universitaria, Delegaci\u00f3n Coyoac\u00e1n, Ciudad de M\u00e9xico 04510, M\u00e9xico. kleytonbio@yahoo.com.br Jair Israel Barrientos-Lara. Posgrado en Ciencias Biol\u00f3gicas, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Circuito de la Investigaci\u00f3n S/N, Ciudad Universitaria, Delegaci\u00f3n Coyoac\u00e1n, Ciudad de M\u00e9xico 04510, M\u00e9xico. j4ir@me.com Alvarado-Ortega, Jes\u00fas, Cantalice Severiano, Kleyton Magno, Barrientos-Lara, Jair Israel, D\u00edaz-Cruz, Jes\u00fas Alberto, and ThanMarchese, Bruno Andr\u00e9s. 2019. The Huehuetla quarry, a Turonian deposit of marine vertebrates in the Sierra Norte of Puebla, central Mexico. Palaeontologia Electronica 22.1.13A 1-20. https://doi.org/10.26879/921 palaeo-electronica.org/content/2019/2450-huehuetla-turonian-vertebrates Copyright: March 2019 Paleontological Society. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ ALVARADO-ORTEGA ET AL.: HUEHUETLA TURONIAN VERTEBRATES Jes\u00fas Alberto D\u00edaz-Cruz. Posgrado en Ciencias Biol\u00f3gicas, Universidad Nacional Aut\u00f3noma de M\u00e9xico, Circuito de la Investigaci\u00f3n S/N, Ciudad Universitaria, Delegaci\u00f3n Coyoac\u00e1n, Ciudad de M\u00e9xico 04510, M\u00e9xico. vertebrata.j@gmail.com Bruno Andr\u00e9s Than-Marchese. Museo de Paleontolog\u00eda \u201cEliseo Palacios Aguilera\u201d, Secretar\u00eda de Medio Ambiente e Historia Natural, Calzada de Los Hombres Ilustres s/n., Tuxtla Guti\u00e9rrez, Chiapas, M\u00e9xico. bruthmar@gmail.com", "keyphrases": ["huehuetla quarry", "turonian deposit", "marine vertebrate"]}
{"id": "10.1080/02724634.1986.10011607", "title": "The functional morphology of the manus in the tridactyl equids Merychippus and Mesohippus: paleontological inferences from neontological models", "abstract": "ABSTRACT An investigation of the kinematics and mechanics of the manus of extant Equus and Tapirus is used as the basis for interpreting the functional morphology of the manus in the extinct tridactyl equids Mesohippus and Merychippus. The shape of the articular surfaces of each joint in the manus of the extant forms is related to the kinematics of the limb, and the probable soft-tissue anatomy and locomotory kinematics of the two fossils are reconstructed by comparing joint shapes among the four genera. The results support the conclusion of Camp and Smith (1942) that Mesohippus had a padded subunguligrade manus, similar to that of Tapirus, while Merychippus was fully unguligrade like Equus. However, all three equids have similar cursorial adaptations, not shared with Tapirus, which include the structure of the carpus and elongation of the distal segments of the limb. The differences in foot structure between Mesohippus and the unguligrade equids may be related to size. Only two, relatively minor, anatomi...", "keyphrases": ["functional morphology", "manus", "merychippus", "mesohippus", "equus"]}
{"id": "paleo.007466", "title": "The giant pliosaurid that wasn\u2019t: revising the marine reptiles from the Kimmeridgian (Upper Jurassic) of Krzy\u017canowice, Poland", "abstract": "Marine reptiles from the Upper Jurassic of Central Europe are rare and often fragmentary, which hinders their precise taxonomic identification and their placement in a palaeobiogeographic context. Recent fieldwork in the Kimmeridgian of Krzy\u017canowice, Poland, a locality known from turtle remains originally discovered in the 1960s, has reportedly provided additional fossils thought to indicate the presence of a more diverse marine reptile assemblage, including giant pliosaurids, plesiosauroids, and thalattosuchians. Based on its taxonomic composition, the marine tetrapod fauna from Krzy\u017canowice was argued to represent part of the \u201cMatyja-Wierzbowski Line\u201d\u2014a newly proposed palaeobiogeographic belt comprising faunal components transitional between those of the Boreal and Mediterranean marine provinces. Here, we provide a detailed re-description of the marine reptile material from Krzy\u017canowice and reassess its taxonomy. The turtle remains are proposed to represent a \u201cplesiochelyid\u201d thalassochelydian ( Craspedochelys ? sp.) and the plesiosauroid vertebral centrum likely belongs to a cryptoclidid. However, qualitative assessment and quantitative analysis of the jaws originally referred to the colossal pliosaurid Pliosaurus clearly demonstrate a metriorhynchid thalattosuchian affinity. Furthermore, these metriorhynchid jaws were likely found at a different, currently indeterminate, locality. A tooth crown previously identified as belonging to the thalattosuchian Machimosaurus is here considered to represent an indeterminate vertebrate. The revised taxonomy of the marine reptiles from Krzy\u017canowice, as well as the uncertain provenance of the metriorhynchid specimen reported from the locality, cast doubt on the palaeobiogeographic significance of the assemblage.", "keyphrases": ["giant pliosaurid", "marine reptile", "kimmeridgian"]}
{"id": "paleo.011100", "title": "Global Diversity of Brittle Stars (Echinodermata: Ophiuroidea)", "abstract": "This review presents a comprehensive overview of the current status regarding the global diversity of the echinoderm class Ophiuroidea, focussing on taxonomy and distribution patterns, with brief introduction to their anatomy, biology, phylogeny, and palaeontological history. A glossary of terms is provided. Species names and taxonomic decisions have been extracted from the literature and compiled in The World Ophiuroidea Database, part of the World Register of Marine Species (WoRMS). Ophiuroidea, with 2064 known species, are the largest class of Echinodermata. A table presents 16 families with numbers of genera and species. The largest are Amphiuridae (467), Ophiuridae (344 species) and Ophiacanthidae (319 species). A biogeographic analysis for all world oceans and all accepted species was performed, based on published distribution records. Approximately similar numbers of species were recorded from the shelf (n\u200a=\u200a1313) and bathyal depth strata (1297). The Indo-Pacific region had the highest species richness overall (825 species) and at all depths. Adjacent regions were also relatively species rich, including the North Pacific (398), South Pacific (355) and Indian (316) due to the presence of many Indo-Pacific species that partially extended into these regions. A secondary region of enhanced species richness was found in the West Atlantic (335). Regions of relatively low species richness include the Arctic (73 species), East Atlantic (118), South America (124) and Antarctic (126).", "keyphrases": ["echinodermata", "ophiuroidea", "global diversity"]}
{"id": "10.1111/evo.13680", "title": "Evolutionary pathways toward gigantism in sharks and rays", "abstract": "Through elasmobranch (sharks and rays) evolutionary history, gigantism evolved multiple times in phylogenetically distant species, some of which are now extinct. Interestingly, the world's largest elasmobranchs display two specializations found never to overlap: filter feeding and mesothermy. The contrasting lifestyles of elasmobranch giants provide an ideal case study to elucidate the evolutionary pathways leading to gigantism in the oceans. Here, we applied a phylogenetic approach to a global dataset of 459 taxa to study the evolution of elasmobranch gigantism. We found that filter feeders and mesotherms deviate from general relationships between trophic level and body size, and exhibit significantly larger sizes than ectothermic\u2010macropredators. We confirm that filter feeding arose multiple times during the Paleogene, and suggest the possibility of a single origin of mesothermy in the Cretaceous. Together, our results elucidate two main evolutionary pathways that enable gigantism: mesothermic and filter feeding. These pathways were followed by ancestrally large clades and facilitated extreme sizes through specializations for enhancing prey intake. Although a negligible percentage of ectothermic\u2010macropredators reach gigantic sizes, these species lack such specializations and are correspondingly constrained to the lower limits of gigantism. Importantly, the very adaptive strategies that enabled the evolution of the largest sharks can also confer high extinction susceptibility.", "keyphrases": ["gigantism", "shark", "evolutionary pathway"]}
{"id": "10.1111/j.1469-8137.2011.03794.x", "title": "Establishing a time-scale for plant evolution.", "abstract": "\u2022 Plants have utterly transformed the planet, but testing hypotheses of causality requires a reliable time-scale for plant evolution. While clock methods have been extensively developed, less attention has been paid to the correct interpretation and appropriate implementation of fossil data. \u2022 We constructed 17 calibrations, consisting of minimum constraints and soft maximum constraints, for divergences between model representatives of the major land plant lineages. Using a data set of seven plastid genes, we performed a cross-validation analysis to determine the consistency of the calibrations. Six molecular clock analyses were then conducted, one with the original calibrations, and others exploring the impact on divergence estimates of changing maxima at basal nodes, and prior probability densities within calibrations. \u2022 Cross-validation highlighted Tracheophyta and Euphyllophyta calibrations as inconsistent, either because their soft maxima were overly conservative or because of undetected rate variation. Molecular clock analyses yielded estimates ranging from 568-815 million yr before present (Ma) for crown embryophytes and from 175-240 Ma for crown angiosperms. \u2022 We reject both a post-Jurassic origin of angiosperms and a post-Cambrian origin of land plants. Our analyses also suggest that the establishment of the major embryophyte lineages occurred at a much slower tempo than suggested in most previous studies. These conclusions are entirely compatible with current palaeobotanical data, although not necessarily with their interpretation by palaeobotanists.", "keyphrases": ["time-scale", "plant evolution", "calibration"]}
{"id": "paleo.007612", "title": "Ancestor\u2013descendant relationships in evolution: origin of the extant pygmy right whale, Caperea marginata", "abstract": "Ancestor\u2013descendant relationships (ADRs), involving descent with modification, are the fundamental concept in evolution, but are usually difficult to recognize. We examined the cladistic relationship between the only reported fossil pygmy right whale, \u2020Miocaperea pulchra, and its sole living relative, the enigmatic pygmy right whale Caperea marginata, the latter represented by both adult and juvenile specimens. \u2020Miocaperea is phylogenetically bracketed between juvenile and adult Caperea marginata in morphologically based analyses, thus suggesting a possible ADR\u2014the first so far identified within baleen whales (Cetacea: Mysticeti). The \u2020Miocaperea\u2013Caperea lineage may show long-term morphological stasis and, in turn, punctuated equilibrium.", "keyphrases": ["pygmy", "whale", "ancestor\u2013descendant relationship"]}
{"id": "paleo.008923", "title": "Global microbial carbonate proliferation after the end-Devonian mass extinction: Mainly controlled by demise of skeletal bioconstructors", "abstract": "Microbial carbonates commonly flourished following mass extinction events. The end-Devonian (Hangenberg) mass extinction event is a first-order mass extinction on the scale of the \u2018Big Five\u2019 extinctions. However, to date, it is still unclear whether global microbial carbonate proliferation occurred after the Hangenberg event. The earliest known Carboniferous stromatolites on tidal flats are described from intertidal environments of the lowermost Tournaisian (Qianheishan Formation) in northwestern China. With other early Tournaisian microbe-dominated bioconstructions extensively distributed on shelves, the Qianheishan stromatolites support microbial carbonate proliferation after the Hangenberg extinction. Additional support comes from quantitative analysis of the abundance of microbe-dominated bioconstructions through the Famennian and early Tournaisian, which shows that they were globally distributed (between 40\u00b0 latitude on both sides of the palaeoequator) and that their abundance increased distinctly in the early Tournaisian compared to the latest Devonian (Strunian). Comparison of variations in the relative abundance of skeleton- versus microbe-dominated bioconstructions across the Hangenberg and \u2018Big Five\u2019 extinctions suggests that changes in abundance of skeletal bioconstructors may play a first-order control on microbial carbonate proliferation during extinction transitions but that microbial proliferation is not a general necessary feature after mass extinctions.", "keyphrases": ["microbial carbonate proliferation", "mass extinction", "skeletal bioconstructor"]}
{"id": "10.1098/rspb.2013.2624", "title": "First glimpse into Lower Jurassic deep-sea biodiversity: in situ diversification and resilience against extinction", "abstract": "Owing to the assumed lack of deep-sea macrofossils older than the Late Cretaceous, very little is known about the geological history of deep-sea communities, and most inference-based hypotheses argue for repeated recolonizations of the deep sea from shelf habitats following major palaeoceanographic perturbations. We present a fossil deep-sea assemblage of echinoderms, gastropods, brachiopods and ostracods, from the Early Jurassic of the Glasenbach Gorge, Austria, which includes the oldest known representatives of a number of extant deep-sea groups, and thus implies that in situ diversification, in contrast to immigration from shelf habitats, played a much greater role in shaping modern deep-sea biodiversity than previously thought. A comparison with coeval shelf assemblages reveals that, at least in some of the analysed groups, significantly more extant families/superfamilies have endured in the deep sea since the Early Jurassic than in the shelf seas, which suggests that deep-sea biota are more resilient against extinction than shallow-water ones. In addition, a number of extant deep-sea families/superfamilies found in the Glasenbach assemblage lack post-Jurassic shelf occurrences, implying that if there was a complete extinction of the deep-sea fauna followed by replacement from the shelf, it must have happened before the Late Jurassic.", "keyphrases": ["deep-sea biodiversity", "situ diversification", "biota"]}
{"id": "10.1080/03115518.2016.1184898", "title": "Unexpected diversity of ratites (Aves, Palaeognathae) in the early Cenozoic of South America: palaeobiogeographical implications", "abstract": "Agnolin, F.L., July 2016. Unexpected diversity of ratites (Aves, Palaeognathae) in the early Cenozoic of South America: palaeobiogeographical implications. Alcheringa 41, xxx\u2013xxx. ISSN 0311-5518. Ratitae is represented in South America exclusively by Rheidae. Recently, the oldest purported fossil rheid, Diogenornis fragilis, was attributed by several authors to various other ratite clades. A new revision of museum fossil specimens from Argentina has resulted in the discovery of several ratite specimens that clearly do not belong to Rheidae, but resemble other clades. The newly identified specimens derive from Paleogene and Miocene strata. The great diversity of non-rheid Patagonian ratites ended via extinction of several groups by the late Miocene, probably owing to enhanced aridity that also favoured the dispersal of arid-adapted rheids. The new specimens described here reinforce the hypothesis that the traditional vicariant biogeographical model, which proposes ratite clades originated exclusively before the breakup of the Gondwana supercontinent, is questionable owing to the unexpected diversity of various ratite clades in South America, and also in Europe and Africa. This might indicate that the history of Ratitae was more complex than previously envisioned. Federico L. Agnolin* [fedeagnolin@yahoo.com.ar], Laboratorio de Anatom\u00eda Comparada y Evoluci\u00f3n de los Vertebrados, Museo Argentino de Ciencias Naturales \u2018Bernardino Rivadavia\u2019, Av. \u00c1ngel Gallardo, 470 (1405), Buenos Aires, Argentina. *Also affiliated with: Fundaci\u00f3n de Historia Natural \u2018F\u00e9lix de Azara\u2019, Departamento de Ciencias Naturales y Antropolog\u00eda, Universidad Maim\u00f3nides, Hidalgo 775 (C1405BDB) Ciudad Aut\u00f3noma de Buenos Aires, Rep\u00fablica Argentina.", "keyphrases": ["palaeognathae", "early cenozoic", "palaeobiogeographical implication"]}
{"id": "10.1126/sciadv.aav9106", "title": "New evidence of broader diets for archaic Homo populations in the northwestern Mediterranean", "abstract": "Taphonomic data suggest that early humans in Europe had more variable diet breadths than assumed by current evolutionary models. Investigating diet breadth is critical for understanding how archaic Homo populations, including Neanderthals, competed for seasonally scarce resources. The current consensus in Western Europe is that ungulates formed the bulk of the human diet during the Lower and Middle Paleolithic, while small fast prey taxa were virtually ignored. Here, we present a multisite taphonomic study of leporid assemblages from Southern France that supports frequent exploitation of small fast game during marine isotope stages 11 to 3. Along with recent evidence from Iberia, our results indicate that the consumption of small fast game was more common prior to the Upper Paleolithic than previously thought and that archaic hominins from the northwestern Mediterranean had broader diets than those from adjacent regions. Although likely of secondary importance relative to ungulates, the frequent exploitation of leporids documented here implies that human diet breadths were substantially more variable within Europe than assumed by current evolutionary models.", "keyphrases": ["archaic homo population", "northwestern mediterranean", "broad diet"]}
{"id": "10.1126/science.1256484", "title": "Early Levallois technology and the Lower to Middle Paleolithic transition in the Southern Caucasus", "abstract": "An early assemblage of obsidian artifacts Levallois technology is the name for the stone knapping technique used to create tools thousands of years ago. The technique appeared in the archeological record across Eurasia 200 to 300 thousand years ago (ka) and appeared earlier in Africa. Adler et al. challenge the hypothesis that the technique's appearance in Eurasia was the result of the expansion of hominins from Africa. Levallois obsidian artifacts in the southern Caucasus, dated at 335 to 325 ka, are the oldest in Eurasia. This suggests that Levallois technology may have evolved independently in different hominin populations. Stone technology cannot thus be used as a reliable indicator of Paleolithic human population change and expansion. Science, this issue p. 1609 An assemblage of obsidian artifacts suggests independent origins of stone knapping in different hominin populations. The Lower to Middle Paleolithic transition (~400,000 to 200,000 years ago) is marked by technical, behavioral, and anatomical changes among hominin populations throughout Africa and Eurasia. The replacement of bifacial stone tools, such as handaxes, by tools made on flakes detached from Levallois cores documents the most important conceptual shift in stone tool production strategies since the advent of bifacial technology more than one million years earlier and has been argued to result from the expansion of archaic Homo sapiens out of Africa. Our data from Nor Geghi 1, Armenia, record the earliest synchronic use of bifacial and Levallois technology outside Africa and are consistent with the hypothesis that this transition occurred independently within geographically dispersed, technologically precocious hominin populations with a shared technological ancestry.", "keyphrases": ["levallois technology", "middle paleolithic transition", "southern caucasus"]}
{"id": "10.1029/2000PA000567", "title": "Paleotemperatures and ice volume of the past 27 Myr revisited with paired Mg/Ca and 18O/16O measurements on benthic foraminifera", "abstract": "[1]\u00a0We explore the applicability of paired Mg/Ca and 18O/16O measurements on benthic foraminifera from Southern Ocean site 747 to paleoceanographic reconstructions on pre-Pleistocene timescales. We focus on the late Oligocene through Pleistocene (27\u20130 Ma) history of paleotemperatures and the evolution of the \u03b418O values of seawater (\u03b418Osw) at a temporal resolution of \u223c100\u2013200 kyr. Absolute paleotemperature estimates depend on assumptions of how Mg/Ca ratios of seawater have changed over the past 27 Myr, but relative changes that occur on geologically brief timescales are robust. Results indicate that at the Oligocene to Miocene boundary (23.8 Ma), temperatures lag the increase in global ice-volume deduced from benthic foraminiferal \u03b418O values, but the smaller-scale Miocene glaciations are accompanied by ocean cooling of \u223c1\u00b0C. During the mid-Miocene phase of Antarctic ice sheet growth (\u223c15\u201313 Ma), water temperatures cool by \u223c3\u00b0C. Unlike the benthic foraminiferal \u03b418O values, which remain relatively constant thereafter, temperatures vary (by 3\u00b0C) and reach maxima at \u223c12 and \u223c8.5 Ma. The onset of significant Northern Hemisphere glaciation during the late Pliocene is synchronous with an \u223c4\u00b0C cooling at site 747. A comparison of our \u03b418Osw curve to the Haq et al. [1987] sea level curve yields excellent agreement between sequence boundaries and times of increasing seawater 18O/16O ratios. At \u223c12\u201311 Ma in particular, when benthic foraminiferal \u03b418O values do not support a further increase in ice volume, the \u03b418Osw curve comes to a maximum that corresponds to a major mid-Miocene sea level regression. The agreement between the character of our Mg/Ca-based \u03b418Osw curve and sequence stratigraphy demonstrates that benthic foramaniferal Mg/Ca ratios can be used to trace the \u03b418Osw on pre-Pleistocene timescales despite a number of uncertainties related to poorly constrained temperature calibrations and paleoseawater Mg/Ca ratios. The Mg/Ca record also highlights that deep ocean temperatures can vary independently and unexpectedly from ice volume changes, which can lead to misinterpretations of the \u03b418O record.", "keyphrases": ["ice volume", "benthic foraminifera", "ocean cooling", "paleotemperature"]}
{"id": "10.1126/science.1211028", "title": "Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification", "abstract": "Molecular phylogenetic analysis, calibrated with fossils, resolves the time frame of the mammalian radiation. Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.", "keyphrases": ["cretaceous terrestrial revolution", "phylogeny", "placentalia"]}
{"id": "paleo.005275", "title": "A toothless dwarf dolphin (Odontoceti: Xenorophidae) points to explosive feeding diversification of modern whales (Neoceti)", "abstract": "Toothed whales (Odontoceti) are adapted for catching prey underwater and possess some of the most derived feeding specializations of all mammals, including the loss of milk teeth (monophyodonty), high tooth count (polydonty), and the loss of discrete tooth classes (homodonty). Many extant odontocetes possess some combination of short, broad rostra, reduced tooth counts, fleshy lips, and enlarged hyoid bones\u2014all adaptations for suction feeding upon fishes and squid. We report a new fossil odontocete from the Oligocene (approx. 30 Ma) of South Carolina (Inermorostrum xenops, gen. et sp. nov.) that possesses adaptations for suction feeding: toothlessness and a shortened rostrum (brevirostry). Enlarged foramina on the rostrum suggest the presence of enlarged lips or perhaps vibrissae. Phylogenetic analysis firmly places Inermorostrum within the Xenorophidae, an early diverging odontocete clade typified by long-snouted, heterodont dolphins. Inermorostrum is the earliest obligate suction feeder within the Odontoceti, a feeding mode that independently evolved several times within the clade. Analysis of macroevolutionary trends in rostral shape indicate stabilizing selection around an optimum rostral shape over the course of odontocete evolution, and a post-Eocene explosion in feeding morphology, heralding the diversity of feeding behaviour among modern Odontoceti.", "keyphrases": ["odontoceti", "xenorophidae", "whale"]}
{"id": "paleo.011151", "title": "Bayesian Inference of Sampled Ancestor Trees for Epidemiology and Fossil Calibration", "abstract": "Phylogenetic analyses which include fossils or molecular sequences that are sampled through time require models that allow one sample to be a direct ancestor of another sample. As previously available phylogenetic inference tools assume that all samples are tips, they do not allow for this possibility. We have developed and implemented a Bayesian Markov Chain Monte Carlo (MCMC) algorithm to infer what we call sampled ancestor trees, that is, trees in which sampled individuals can be direct ancestors of other sampled individuals. We use a family of birth-death models where individuals may remain in the tree process after sampling, in particular we extend the birth-death skyline model [Stadler et al., 2013] to sampled ancestor trees. This method allows the detection of sampled ancestors as well as estimation of the probability that an individual will be removed from the process when it is sampled. We show that even if sampled ancestors are not of specific interest in an analysis, failing to account for them leads to significant bias in parameter estimates. We also show that sampled ancestor birth-death models where every sample comes from a different time point are non-identifiable and thus require one parameter to be known in order to infer other parameters. We apply our phylogenetic inference accounting for sampled ancestors to epidemiological data, where the possibility of sampled ancestors enables us to identify individuals that infected other individuals after being sampled and to infer fundamental epidemiological parameters. We also apply the method to infer divergence times and diversification rates when fossils are included along with extant species samples, so that fossilisation events are modelled as a part of the tree branching process. Such modelling has many advantages as argued in the literature. The sampler is available as an open-source BEAST2 package (https://github.com/CompEvol/sampled-ancestors).", "keyphrases": ["tree", "mcmc", "diversification rate", "fossil taxa", "bdss"]}
{"id": "10.1111/j.0031-0239.2003.00301.x", "title": "The species taxonomy of the sauropodomorph dinosaurs from the L\u00f6wenstein Formation (Norian, Late Triassic) of Germany", "abstract": "The species taxonomy of the sauropodomorph dinosaurs from the L\u00f6wenstein Formation of Germany is examined. Previous work has classified these into two taxa: Sellosaurus gracilis from a number of localities and the widespread Plateosaurus engelhardti from a single monospecific accumulation in the L\u00f6wenstein Formation, near the town of Trossingen. The current hypodigm of Sellosaurus gracilis is found to contain a substantial amount of variation. This includes differences in the dentition, structure of the skull, composition of the sacrum and the structure of the caudal vertebrae and pelvis. This variation was analysed using a specimen\u2013based parsimony analysis of the sauropodomorphs from the L\u00f6wenstein Formation. It was found that two discrete taxa comprise the current hypodigm of Sellosaurus. The more common of these two is a plesiomorphic form for which the correct name is Efraasia minor comb. nov. The less common form (which includes the holotype of Sellosaurus gracilis) is found to share a number of synapomorphies with Plateosaurus engelhardti and is placed in this genus as Plateosaurus gracilis", "keyphrases": ["species taxonomy", "sauropodomorph dinosaur", "germany", "sellosaurus gracilis"]}
{"id": "paleo.005575", "title": "Principal component analysis as an alternative treatment for morphometric characters: phylogeny of caseids as a case study", "abstract": "In a recent study, the phylogeny of Caseidae (a herbivorous family of Palaeozoic synapsids belonging to the paraphyletic grade known as pelycosaurs) was analysed with a dataset employing more than three hundred continuous morphological characters in an effort to follow the principles of total evidence. Continuous characters are a source of great debate, with disagreements surrounding their suitability for and treatment in phylogenetic analysis. A number of shortcomings were identified in the handling of continuous characters in this study of caseids, including the use of gap weighting to discretize the characters and potential issues with redundancy and character non\u2010independence. Therefore, an alternative treatment for these characters is suggested here. First, rather than using gap weighting, the continuous characters were analysed in the program TNT, in which the raw values can be treated as continuous rather than discrete. Second, prior to the phylogenetic analysis, the continuous characters were subjected to a log\u2010ratio principal component analysis, and then the principal components were included in the character matrix rather than the raw ratios. Analysing the original data in TNT produced little difference in the results, but using the principal components as continuous characters resulted in alternative positions for Caseopsis agilis, Ennatosaurus tecton and Caseoides sanangeloensis. The differences are judged to be due to the reduced redundancy of the characters, the smaller number of principal components not overwhelming the discrete characters and the use of a scaling method which allows principal components with a higher variance to have a greater influence on the analysis. The positions of highly fragmentary fossils depended heavily on the method used to treat the missing characters in the principal component analysis, and so the method proposed here is not recommended for analysing very incomplete taxa.", "keyphrases": ["alternative treatment", "caseid", "principal component analysis"]}
{"id": "10.4202/app.2010.0071", "title": "Morphology and Evolutionary Significance of the Atlas-Axis Complex in Varanopid Synapsids", "abstract": "The atlas-axis complex has been described in few Palaeozoic taxa, with little effort being placed on examining variation of this structure within a small clade. Most varanopids, members of a clade of gracile synapsid predators, have well preserved atlas-axes permitting detailed descriptions and examination of morphological variation. This study indicates that the size of the transverse processes on the axis and the shape of the axial neural spine vary among members of this clade. In particular, the small mycterosaurine varanopids possess small transverse processes that point posteroventrally, and the axial spine is dorsoventrally short, with a flattened dorsal margin in lateral view. The larger varanodontine varanopids have large transverse processes with a broad base, and a much taller axial spine with a rounded dorsal margin in lateral view. Based on outgroup comparisons, the morphology exhibited by the transverse processes is interpreted as derived in varanodontines, whereas the morphology of the axial spine is derived in mycterosaurines. The axial spine anatomy of Middle Permian South African varanopids is reviewed and our interpretation is consistent with the hypothesis that at least two varanopid taxa are present in South Africa, a region overwhelmingly dominated by therapsid synapsids and parareptiles.", "keyphrases": ["atlas-axis complex", "spine", "lateral view", "base", "morphology"]}
{"id": "paleo.010935", "title": "Avian tail ontogeny, pygostyle formation, and interpretation of juvenile Mesozoic specimens", "abstract": "The avian tail played a critical role in the evolutionary transition from long- to short-tailed birds, yet its ontogeny in extant birds has largely been ignored. This deficit has hampered efforts to effectively identify intermediate species during the Mesozoic transition to short tails. Here we show that fusion of distal vertebrae into the pygostyle structure does not occur in extant birds until near skeletal maturity, and mineralization of vertebral processes also occurs long after hatching. Evidence for post-hatching pygostyle formation is also demonstrated in two Cretaceous specimens, a juvenile enantiornithine and a subadult basal ornithuromorph. These findings call for reinterpretations of Zhongornis haoae, a Cretaceous bird hypothesized to be an intermediate in the long- to short-tailed bird transition, and of the recently discovered coelurosaur tail embedded in amber. Zhongornis, as a juvenile, may not yet have formed a pygostyle, and the amber-embedded tail specimen is reinterpreted as possibly avian. Analyses of relative pygostyle lengths in extant and Cretaceous birds suggests the number of vertebrae incorporated into the pygostyle has varied considerably, further complicating the interpretation of potential transitional species. In addition, this analysis of avian tail development reveals the generation and loss of intervertebral discs in the pygostyle, vertebral bodies derived from different kinds of cartilage, and alternative modes of caudal vertebral process morphogenesis in birds. These findings demonstrate that avian tail ontogeny is a crucial parameter specifically for the interpretation of Mesozoic specimens, and generally for insights into vertebrae formation.", "keyphrases": ["pygostyle formation", "mesozoic specimen", "extant bird", "avian tail ontogeny"]}
{"id": "paleo.004160", "title": "First fossil records of the tholichthys larval stage of butterfly fishes (Perciformes, Chaetodontidae), from the Oligocene of Europe", "abstract": "The first fossils of the tholichthys larval stage of a chaetodontid from the lower Oligocene (Rupelian, Fish Shales; about 30.1 MYA) of Frauenweiler (Baden-Wu \u00a8rttemberg, S Germany) are described, along with two less well-preserved probable tholichthys from the lower Oligocene Menilite-Formation (IPM3, 30-29 MYA and IPM4A, 29-28 MYA) of Przemys \u00b4l (Outer Carpathians, SE Poland). The fossils are compared with tholichthys larvae of the extant genus of Chaetodontidae to which they are most similar, namely Chaetodon. The German specimens are identified as tholichthys larvae by the plate-like expansions of the supracleithrum and posttemporal that extend posteriorly well behind the head and by an expanded preopercle with a large posterior spine; these bones, and the frontals and supraoccipital, are distinctively rugose. The Polish specimen from IPM3 has similar features so it is safe to assume that it also is a chaetodontid tholichthys, whereas the specimen from IPM4A is so poorly preserved that it can only very tentatively be referred to the Chaetodontidae. The occurrence of tholichthys larvae prompts reconsideration of the paleoenvironmental situation at their respective fossil sites.", "keyphrases": ["tholichthy larval stage", "chaetodontidae", "oligocene"]}
{"id": "10.1017/pab.2014.17", "title": "A new approach using high-resolution computed tomography to test the buoyant properties of chambered cephalopod shells", "abstract": "Abstract. \n The chambered shell of modern cephalopods functions as a buoyancy apparatus, allowing the animal to enter the water column without expending a large amount of energy to overcome its own weight. Indeed, the chambered shell is largely considered a key adaptation that allowed the earliest cephalopods to leave the ocean floor and enter the water column. It has been argued by some, however, that the iconic chambered shell of Paleozoic and Mesozoic ammonoids did not provide a sufficiently buoyant force to compensate for the weight of the entire animal, thus restricting ammonoids to a largely benthic lifestyle reminiscent of some octopods. Here we develop a technique using high-resolution computed tomography to quantify the buoyant properties of chambered shells without reducing the shell to ideal spirals or eliminating inherent biological variability by using mathematical models that characterize past work in this area. This technique has been tested on Nautilus pompilius and is now extended to the extant deep-sea squid Spirula spirula and the Jurassic ammonite Cadoceras sp. hatchling. Cadoceras is found to have possessed near-neutral to positive buoyancy if hatched when the shell possessed between three and five chambers. However, we show that the animal could also overcome degrees of negative buoyancy through swimming, similar to the paralarvae of modern squids. These calculations challenge past inferences of benthic life habits based solely on calculations of negative buoyancy. The calculated buoyancy of Cadoceras supports the possibility of planktonic dispersal of ammonite hatchlings. This information is essential to understanding ammonoid ecology as well as biotic interactions and has implications for the interpretation of geochemical data gained from the isotopic analysis of the shell.", "keyphrases": ["high-resolution", "tomography", "buoyant property"]}
{"id": "paleo.003831", "title": "A small podocnemidoid (Pleurodira, Pelomedusoides) from the Late Cretaceous of Brazil, and the innervation and carotid circulation of side\u2010necked turtles", "abstract": "Pleurodires are less diverse than cryptodires, together forming the two major lineages of crown turtles. Their fossil record, however, is rich. A particularly large number of fossil pleurodires, many belonging to the Podocnemidoidae, has been recovered from the Upper Cretaceous Bauru Group outcrops of south\u2010central Brazil. Herein we describe an additional pleurodire from this region, Amabilis uchoensis gen. et sp. nov., based on a partially preserved skull. A. uchoensis is recognized as belonging to the Podocnemidoidae by the small entrance to the antrum postoticum and completely developed cavum pterygoidei, being unique among other non\u2010podocnemidid podocnemidoids for its medially open fenestra postotica and absent basioccipital\u2013opisthotic contact. Our cladistic analysis places A. uchoensis as a sister taxon to Hamadachelys + other podocnemidoids. We further explore the neuroanatomy of side\u2010necked turtles with the aid of micro\u2010computed tomography of specimens of the main pleurodiran lineages. Our data shed light on the different carotid circulation patterns in pleurodires, and we propose new phylogenetic characters to describe the neuroanatomical variation of the group. Optimization of these characters shows two independent acquisitions of a foramen for the palatal branch of the carotid in chelids and podocnemidoids, and a unique loss of the vidian nerve canal in chelids, in turtles in general.", "keyphrases": ["podocnemidoid", "pleurodira", "turtle"]}
{"id": "10.1130/g38181.1", "title": "High-precision time-space correlation through coupled apatite and zircon tephrochronology: An example from the Permian-Triassic boundary in South China", "abstract": "Accurate and precise dating of individual volcanogenic beds that spread across multiple sedimentary successions is a powerful tool to untangle stratigraphic age contradictions, since these horizons are deposited synchronously. In this study, we show that combining apatite chemistry with zircon age, Th/U ratio, and Hf isotope composition leads to reliable lateral correlation of volcanic horizons across sections representing disparate biological, chemical, and physical paleoenvironments. We correlate two volcanogenic horizons across six sedimentary sections straddling the Permian-Triassic boundary (PTB) in the Nanpanjiang Basin (South China), including the last Permian bed below the unconformity in shallow-water sections of the Luolou Platform. We place the PTB in our sections at the marked lithological change in order to avoid the difficulties that arise from the diachronism of the index conodont Hindeodus parvus, the first occurrence of which defines the PTB at the Global Stratotype Section and Point at Meishan. Our new data demonstrate that these volcanogenic beds are contemporaneous and cogenetic, allowing us to pool high-precision U-Pb zircon ages from the same horizon across several sections, and dating the last Permian volcanic event in this basin at 252.048 \u00b1 0.033 Ma. We show that the mineral chemistry of apatite and zircon of intra- and interbasin-wide volcanogenic beds provides tie points against which biozones, carbon isotopes, astronomic cycles, and geomagnetic polarity time series can be stringently tested.", "keyphrases": ["apatite", "permian-triassic boundary", "south china"]}
{"id": "10.1139/cjes-2015-0210", "title": "Paleo-ocean redox environments of the Upper Ordovician Wufeng and the first member in lower Silurian Longmaxi formations in the Jiaoshiba area, Sichuan Basin", "abstract": "A study of paleo-ocean redox environments is important for understanding the deposition of black shale and has practical implications for shale gas exploration. Here, we selected a total of 52 shale samples from JY1 Well, the first shale gas well of commercial exploitation in China, to analyze the redox conditions of Upper Ordovician Wufeng (O3w) and the first member in lower Silurian Longmaxi shale (S1l1) in the Jiaoshiba area. Abundant pyrite framboids are observed in these units, with average framboid diameters ranging from 3.1 to 4.7 \u03bcm and maximum diameter about 10 \u03bcm. Analyses of redox-sensitive trace elements suggest the redox environment has evolved from an anoxic condition in the bottom of Member A to a dysoxic condition in the top of Member A, and to a dysoxic\u2013oxic environment in Members B and C. Graptolite and radiolarian are discovered in these shale samples, indicating an oxygenated seafloor, which seems to be contradictory to the results from pyrite framboids and redox-sensitive trace elemen...", "keyphrases": ["upper ordovician wufeng", "sichuan basin", "paleo-ocean redox environment"]}
{"id": "10.1111/1475-4983.00158", "title": "The Ichnogenus Undichna, With Examples From The Permian Of The Falkland Islands", "abstract": "Abundant, well\u2010preserved and variable species of Undichna are described from the Permian of the Falkland Islands. The environment is considered to be non\u2010marine and the traces are associated with turbidite and rhythmite deposits. There are strong similarities between the Undichna and other ichnogenera of the Falkland Islands and those of the Eastern Cape Province of South Africa, thus strengthening the view that the missing eastern end of the Permian Karoo Basin is present in the Falklands. Undichna binaU. insolentia occur associated within glacially influenced rhythmite and turbidite facies of a non\u2010marine basin in the Cantera Formation, Camilla Creek, East Falkland. U. quina isp. nov. occurs on Sea Lion Island and is associated with thin (mm\u2013cm scale) graded interbeds between thicker amalgamated sandstones in a sequence deposited by density currents derived from a delta feeding the same non\u2010marine basin. The elements that comprise Undichna traces are (1) single sinusoidal grooves, (2) paired sinusoidal grooves, (3) broad shallow grooves, (4) repeated arcuate imprints, (5) irregular grooves, (6) striated brush\u2010like imprints. A distinct, repeated morphology is only produced by a constant activity of the tracemaker (generally a fish). Irregular activity (e.g. acceleration, sharp turns) or current action produces non\u2010constant morphology, lacking the defining regularity of the ichnogenus Undichna. Such irregular forms can frequently be identified as a modified expression of a described ichnospecies, but morphologically do not fall within the definition of the ichnospecies. It is suggested that rather than create new names they should be referred to as \u2018cf. Undichna isp.\u2019 (irregular form).", "keyphrases": ["ichnogenus undichna", "permian", "falkland islands"]}
{"id": "10.1002/jez.501", "title": "The skeletal kinematics of lung ventilation in three basal bird taxa (emu, tinamou, and guinea fowl).", "abstract": "In vivo visceral and skeletal kinematics of lung ventilation was examined using cineradiography in two palaeognaths, the emu (Dromaius novaehollandiae) and the Chilean tinamou (Nothoprocta perdicaria), and a basal neognath, the helmeted guinea fowl (Numida meleagris). Upon inspiration, the thorax expands in all dimensions. The vertebral ribs swing forward and upward, thereby increasing the transverse diameter of the trunk. The consistent location of the parapophysis throughout the dorsal vertebral series, ventral and cranial to the diapophysis, ensures a relatively uniform lateral expansion. An increase in the angle between the vertebral and the sternal ribs causes the sternal ribs to push the sternum ventrally. Owing to the greater length of the caudal sternal ribs, the caudal sternal margin is displaced further ventrally than the cranial sternal margin. When observed in lateral view, sternal movement is not linear, but elliptical. The avian thorax is highly constrained in its movement when compared with crocodylians, the other extant archosaur clade. Birds lack a lumbar region and intermediate ribs. Sternal ribs are completely ossified, and have a bicondylar articulation with the sternum. Considering the importance of pressure differences between cranial and caudal air sac complexes for the generation of unidirectional air flow in the avian lung, it is hypothesized that a decrease in the degrees of freedom of movement of the avian trunk skeleton, greater expansion of the ventrocaudal trunk region, and elliptical sternal movement may represent specific adaptations for fine-tuned control over air flow within the complex avian pulmonary system.", "keyphrases": ["skeletal kinematic", "lung ventilation", "guinea fowl"]}
{"id": "10.1111/brv.12086", "title": "Major issues in the origins of ray\u2010finned fish (Actinopterygii) biodiversity", "abstract": "Ray\u2010finned fishes (Actinopterygii) dominate modern aquatic ecosystems and are represented by over 32000 extant species. The vast majority of living actinopterygians are teleosts; their success is often attributed to a genome duplication event or morphological novelties. The remainder are \u2018living fossils\u2019 belonging to a few depauperate lineages with long\u2010retained ecomorphologies: Polypteriformes (bichirs), Holostei (bowfin and gar) and Chondrostei (paddlefish and sturgeon). Despite over a century of systematic work, the circumstances surrounding the origins of these clades, as well as their basic interrelationships and diagnoses, have been largely mired in uncertainty. Here, I review the systematics and characteristics of these major ray\u2010finned fish clades, and the early fossil record of Actinopterygii, in order to gauge the sources of doubt. Recent relaxed molecular clock studies have pushed the origins of actinopterygian crown clades to the mid\u2010late Palaeozoic [Silurian\u2013Carboniferous; 420 to 298 million years ago (Ma)], despite a diagnostic body fossil record extending only to the later Mesozoic (251 to 66 Ma). This disjunct, recently termed the \u2018Teleost Gap\u2019 (although it affects all crown lineages), is based partly on calibrations from potential Palaeozoic stem\u2010taxa and thus has been attributed to poor fossil sampling. Actinopterygian fossils of appropriate ages are usually abundant and well preserved, yet long\u2010term neglect of this record in both taxonomic and systematic studies has exacerbated the gaps and obscured potential synapomorphies. At the moment, it is possible that later Palaeozoic\u2010age teleost, holostean, chondrostean and/or polypteriform crown taxa sit unrecognized in museum drawers. However, it is equally likely that the \u2018Teleost Gap\u2019 is an artifact of incorrect attributions to extant lineages, overwriting both a post\u2010Palaeozoic crown actinopterygian radiation and the ecomorphological diversity of stem\u2010taxa.", "keyphrases": ["actinopterygii", "ecosystem", "teleost", "interrelationship"]}
{"id": "paleo.010832", "title": "The appearance and duration of the Jehol Biota: Constraint from SIMS U-Pb zircon dating for the Huajiying Formation in northern China", "abstract": "Significance The Jehol Biota is well known for producing exceptionally preserved specimens of feathered dinosaurs, early birds, mammals, as well as insects and early flowering plants, thus providing key evidence for understanding the early evolution of birds and for reconstructing the Early Cretaceous terrestrial ecosystem. Here, we present eight SIMS U-Pb zircon ages from the Huajiying Formation, the lowest Jehol fossil-bearing deposits in northern China, which have placed stringent age controls on the early phase of the Jehol Biota, and have extended the temporal range of the Jehol Biota to over 15 My. Our findings will shed light on the evolutionary radiation of the Jehol Biota as well as the origins of major vertebrate groups in the Early Cretaceous. The Lower Cretaceous Huajiying Formation of the Sichakou Basin in northern Hebei Province, northern China contains key vertebrate taxa of the early Jehol Biota, e.g., Protopteryx fengningensis, Archaeornithura meemannae, Peipiaosteus fengningensis, and Eoconfuciusornis zhengi. This formation arguably documents the second-oldest bird-bearing horizon, producing the oldest fossil records of the two major Mesozoic avian groups Enantiornithes and Ornithuromorpha. Hence, precisely determining the depositional ages of the Huajiying Formation would advance our understanding of the evolutionary history of the Jehol Biota. Here we present secondary ion mass spectrometry (SIMS) U-Pb zircon analysis results of eight interbedded tuff/tuffaceous sandstone samples from the Huajiying Formation. Our findings, combined with previous radiometric dates, suggest that the oldest enantiornithine and ornithuromorph birds in the Jehol Biota are \u223c129\u2212131 Ma, and that the Jehol Biota most likely first appeared at \u223c135 Ma. This expands the biota\u2019s temporal distribution from late Valanginian to middle Aptian with a time span of about 15 My.", "keyphrases": ["jehol biota", "huajiying formation", "northern china", "early evolution", "cretaceous terrestrial ecosystem"]}
{"id": "10.1080/02724634.2020.1805455", "title": "Introduction to Adalatherium hui (Gondwanatheria, Mammalia) from the Late Cretaceous of Madagascar", "abstract": "ABSTRACT Adalatherium hui is a latest Cretaceous (Maastrichtian) gondwanatherian mammal based on only a single specimen, a virtually complete, articulated, and well-preserved skull and postcranial skeleton. The specimen is the most complete and best preserved of any mammaliaform from the Mesozoic of the southern supercontinent Gondwana. It was discovered in the Anembalemba Member of the Maevarano Formation in the Mahajanga Basin of northwestern Madagascar. The holotype specimen includes the only complete lower jaw and the only postcranial remains known for Gondwanatheria, which, other than the cranium of Vintana sertichi (also from the latest Cretaceous of Madagascar), are represented only by isolated teeth and fragmentary dentaries. Despite being represented by an immature individual, A. hui is third only to V. sertichi and Coloniatherium cilinskii as the largest Mesozoic mammaliaform (based on body fossils) from Gondwana. Here, we (1) review the paucity of mammaliamorph skull and postcranial skeletal material from the Mesozoic of Gondwana relative to the record from Laurasia; (2) review the systematic paleontology of A. hui; (3) provide an overview of the history of discovery of the holotype specimen; (4) detail the preservation of the holotype, its preparation history, and the imaging techniques used to study it; (5) provide an overview of the geological context of A. hui, which indicates that the species lived close to the end-Cretaceous extinction event in a highly seasonal, semiarid climate; and (6) estimate the body mass of A. hui in the context of other Mesozoic mammaliaforms.", "keyphrases": ["madagascar", "maastrichtian", "maevarano formation"]}
{"id": "10.4267/2042/8455", "title": "Morphological variability of Globorotalia menardii (planktonic foraminifera) in two DSDP cores from the Caribbean Sea and the Eastern Equatorial Pacific", "abstract": "Variability in the test of Globorotalia menardii during the past 8 million years has been investigated at DSDP Site 502A (Caribbean Sea) and DSDP Site 503A (Eastern Equatorial Pacific). Measurements were made of spire height (\u2202x), maximum diameter (\u2202y), the tangent angles of the upper and lower peripheral keels (\u03a61, \u03a62, respectively), the number of chambers in the final whorl, and the area of the silhouette in keel view. Four morphotypes alpha, beta, gamma, and delta were distinguished. Morphotype alpha was found in strata ranging in age from the Late Miocene through the Holocene. It shows a continuous increase in \u2202x and \u2202y until the Late Pleistocene. During and after the final closure of the ancient Central American Seaway (between 2.4 Ma and 1.8 Ma) there was a rapid increase in the area of the test in keel view. At the Caribbean Sea site, morphotype beta evolved during the past 0.22 Ma. It is less inflated than alpha and has a more delicate test. In the morphospace of \u2202x vs. \u2202y, morphotypes alpha and beta can be distinguished by a separation line \u2202y = 3.2 * \u2202x - 160 (\u2202x and \u2202y in \u00b5m). Plots of morphotype alpha are below that line, those of beta are above it. Morphotype alpha is taken to be Globorotalia menardii menardii Parker, Jones & Brady (1865) and includes G. menardii 'A' Bolli (1970). Morphotype beta is identified as G. menardii cultrata (d'Orbigny). Morphotypes gamma and delta are extinct Upper Miocene to Pliocene forms which evolved from morphotype alpha. They have a narrower \u03a61 angle and more chambers (\u22657) than morphotype alpha commonly with 5 to 6 chambers (7 in transitional forms). In contemporaneous samples morphotype delta can be distinguished from gamma by a smaller value of \u03a61 and 8 or more chambers in the final whorl. Morphotype gamma is taken to be G. limbata (Fornasini, 1902) and includes the junior synonym G. menardii 'B' Bolli (1970). Morphotype delta is G. multicamerata Cushman & Jarvis (1930). With the exception of the Late Pleistocene development of G. menardii cultrataonly in the Caribbean the morphological changes of G. menardii at DSDP Sites 502A and 503A are similar. The development from the ancestral G. menardii menardii of the G. limbata - G. multicamerata lineage during the Pliocene and of G. menardii cultrata during the Late Pleistocene suggests responses at the two sites to a changing palaeoceanography during and after the formation of the Isthmus of Panama.", "keyphrases": ["planktonic foraminifera", "caribbean sea", "eastern equatorial pacific"]}
{"id": "10.1029/2008PA001703", "title": "Atmospheric \u03b413CO2 and its relation to pCO2 and deep ocean \u03b413C during the late Pleistocene", "abstract": "The ratio of the stable carbon isotopes of atmospheric CO2 (\u03b413CO2) contains valuable information on the processes which are operating on the global carbon cycle. However, current \u03b413CO2 ice core records are still limited in both resolution and temporal coverage, as well as precision. In this study we performed simulations with the carbon cycle box model BICYCLE with special emphasis on atmospheric \u03b413CO2, proposing how changes in \u03b413CO2 might have evolved over the last 740,000 years. We furthermore analyze the relationship between atmospheric \u03b413CO2, pCO2, and deep ocean \u03b413C of dissolved inorganic carbon (DIC) (\u03b413CDIC) in both our modeling framework and proxy records (when available). Our analyses show that mean ocean and deep Pacific \u03b413CDIC are mainly controlled by the glacial/interglacial uptake and release of carbon temporarily stored in the terrestrial biosphere during warmer climate periods. In contrast glacial/interglacial changes in pCO2 and \u03b413CO2 represent mainly a mixture of ocean-related processes superimposed on the slow glacial/interglacial change in terrestrial carbon storage. The different processes influencing atmospheric \u03b413CO2 largely compensate each other and cancel all variability with frequencies of 1/100 kyr\u22121. Large excursions in \u03b413CO2 can a priori be expected, as any small phase difference between the relative timing of the dominant and opposite sign processes might create large changes in \u03b413CO2. Amplitudes in \u03b413CO2 caused by fast terrestrial uptake or release during millennial-scale climate variability depend not only on the amount of transferred carbon but also on the speed of these changes. Those which occur on timescales shorter than a millennium are not detectable in \u03b413CO2 because of gas exchange equilibration with the surface ocean. The \u03b413CO2 signal of fast processes, on the other hand, is largely attenuated in ice core records during the firnification and gas enclosure. We therefore suggest to measure \u03b413CO2 with priority on ice cores with high temporal resolution and select times with rather fast climatic changes.", "keyphrases": ["ocean", "late pleistocene", "global carbon cycle", "atmospheric \u03b413co2"]}
{"id": "10.1017/S0094837300016389", "title": "The roles of mass extinction and biotic interaction in large-scale replacements: a reexamination using the fossil record of stromboidean gastropods", "abstract": "The macroevolutionary processes underlying large-scale biotic replacements are still poorly understood. Opinion remains divided regarding the roles of mass extinction, biotic interaction, and environmental perturbations in these replacement events. Previous attempts to test replacement hypotheses have largely focused on taxonomic diversity patterns. Taxonomic data alone, however, provide little insight about ecological interactions and hence other approaches are needed to understand mechanics of biotic replacements. Here I propose a conceptual model of replacement based on predation-mediated biotic interactions, and attempt a test using analysis of the Cenozoic replacement of the gastropod family Aporrhaidae by a closely related group, the Strombidae. Taxonomic, morphologic, and geographic data analyzed in this study all suggest a replacement of aporrhaids by strombids following the end-Cretaceous mass extinction. While most of the taxonomic replacement was associated with a mass extinction, some replacement also occurred during background times and was mediated by higher origination rates in strombids rather than by higher extinction rates in aporrhaids. Morphologically, the replacement was largely confined to the portion of the morphospace unaffected by the end-Cretaceous extinction. At a global scale, the geographic overlap between the two groups declined through the Cenozoic, reflecting increasing restriction of aporrhaids to colder, temperate waters while strombids flourished in the tropics. However, at a finer geographic scale a more mosaic pattern of replacement is evident and coincides with Eocene and Oligocene climatic fluctuations. The results of this study suggest that mass extinction, long-term biotic interaction, and environmental change can all play significant roles in biotic replacements. Since the relative importance of each factor would vary from one event to another, an understanding of the general nature of large-scale biotic replacements requires a knowledge of the relative intensities of each of these processes.", "keyphrases": ["mass extinction", "biotic interaction", "replacement"]}
{"id": "paleo.003909", "title": "The hydrostatics of Paleozoic ectocochleate cephalopods (Nautiloidea and Endoceratoidea) with implications for modes of life and early colonization of the pelagic zone", "abstract": "Understanding the hydrostatic properties of ectocochleate cephalopods is essential to study the functional morphology of their shells. The conditions for neutral buoyancy, static orientation of the living animal, and their hydrostatic stability are key factors to determine the physical relationships and constraints on cephalopod life habits and paleoecology. The hydrostatics of early orthoconic and cyrtoconic Paleozoic cephalopods were investigated by digitally reconstructing morphotypes within Nautiloidea and Endoceratoidea. Morphotypes were chosen from several traditional orders and include endogastric cyrtocones (Ellesmerocerida and Discosorida), exogastric cyrtocones (Oncocerida), and longi-orthocones (Orthocerida and Endocerida). The extant nautilid, Nautilus pompilius, was also modeled as a reference for the hydrostatics of the Paleozoic cephalopods. All cyrtocone models have similar hydrostatic stability to the Nautilus and only the ellesmerocerid was found to be negatively buoyant. The hydrostatics of the neutrally buoyant cyrtocones suggests that they behaved as relatively poor-swimming demersal or nekto-benthic predators. This mode of life aligns with the largely neritic distribution of individuals belonging to these clades in the Paleozoic. In contrast, the orthocones studied were all capable of neutral buoyancy, much more stable than the Nautilus model, and all had vertical syn vivo orientations in a static setting. The hydrostatic properties of these morphotypes and their largely pelagic distribution support their role as vertical migrants. However, adapically distributed cameral deposits and endosiphuncular deposits would reduce stability, easing deviation from a vertical orientation. These adaptations, along with dorsal color patterns on some species, suggest that active locomotion in orthocones may have been more important than previously thought. David J. Peterman. Department of Earth and Environmental Sciences, Wright State University, Dayton, Ohio, United States of America. peterman.10@wright.edu PETERMAN, BARTON, & YACOBUCCI: CEPHALOPOD HYDROSTATICS 2 Christopher C. Barton. Department of Earth and Environmental Sciences, Wright State University, Dayton, Ohio, United States of America. chris.barton@wright.edu Margaret M. Yacobucci. Department of Geology, Bowling Green State University, Bowling Green, Ohio, United States of America. mmyacob@bgsu.edu", "keyphrases": ["hydrostatic", "paleozoic", "cephalopod"]}
{"id": "paleo.009139", "title": "First record of a basal mammaliamorph from the early Late Triassic Ischigualasto Formation of Argentina", "abstract": "We describe a new probainognathian cynodont, Pseudotherium argentinus, from the early Late Triassic Ischigualasto Formation of Argentina. Pseudotherium adds to a growing assemblage of small Triassic cynodonts that offers new insight into events leading up to the origin of crown Mammalia and the successively more inclusive Mammaliaformes and Mammaliamorpha. Using high-resolution X-ray computed tomography, we illustrate and describe the holotype and only known specimen, which consists of a well-preserved isolated skull. It preserves apomorphic features of the orbit and braincase. Prefrontal and vestigial postorbital bones are present, despite the absence of an ossified postorbital bar. As in Brasilitherium riograndensis, thin turbinal-like bones are present in the nasopharyngeal passage, and we discuss impediments to establishing their identity and function. Compared to more basal cynodonts, the cochlea is elongated but uncoiled and in this and other features it resembles basal mammaliamorphs. Our analysis found weak support for Pseudotherium as the sister taxon of Tritylodontidae. However, a broader assessment of its relationships in light of additional character data from the literature and unpublished computed tomography data suggest that it may be more realistic to view the relationships of Pseudotherium as an unresolved polytomy with tritylodontids, and the taxa referred to as tritheledontids and brasilodontids (groups of variable membership and questionable monophyly). Thus, Pseudotherium may lie just inside or just outside of Mammaliamorpha, and there is also weak character support for its sister taxon relationship with Brasilitherium. Our results amplify previous conclusions that phylogenetic relationships in this adaptive radiation of small cynodonts will remain somewhat uncertain until more complete specimens are recovered, and until high-resolution CT scans of existing specimens become available to the larger community. Toward that goal, we make the CT dataset for the holotype of Pseudotherium argentinus publically available under a Creative Commons license at www.DigiMorph.org.", "keyphrases": ["basal mammaliamorph", "triassic ischigualasto formation", "reptile ancestor"]}
{"id": "paleo.007114", "title": "Locomotory behaviour of early tetrapods from Blue Beach, Nova Scotia, revealed by novel microanatomical analysis", "abstract": "Evidence for terrestriality in early tetrapods is fundamentally contradictory. Fossil trackways attributed to early terrestrial tetrapods long predate the first body fossils from the Late Devonian. However, the Devonian body fossils demonstrate an obligatorily aquatic lifestyle. Complicating our understanding of the transition from water to land is a pronounced gap in the fossil record between the aquatic Devonian taxa and presumably terrestrial tetrapods from the later Early Carboniferous. Recent work suggests that an obligatorily aquatic habit persists much higher in the tetrapod tree than previously recognized. Here, we present independent microanatomical data of locomotor capability from the earliest Carboniferous of Blue Beach, Nova Scotia. The site preserves limb bones from taxa representative of Late Devonian to mid-Carboniferous faunas as well as a rich trackway record. Given that bone remodels in response to functional stresses including gravity and ground reaction forces, we analysed both the midshaft compactness profiles and trabecular anisotropy, the latter using a new whole bone approach. Our findings suggest that early tetrapods retained an aquatic lifestyle despite varied limb morphologies, prior to their emergence onto land. These results suggest that trackways attributed to early tetrapods be closely scrutinized for additional information regarding their creation conditions, and demand an expansion of sampling to better identify the first terrestrial tetrapods.", "keyphrases": ["early tetrapod", "blue beach", "nova scotia"]}
{"id": "10.1029/2006PA001290", "title": "Comparison of two methods to identify live benthic foraminifera: A test between Rose Bengal and CellTracker Green with implications for stable isotope paleoreconstructions", "abstract": "[1]\u00a0The conventional method to distinguish live from dead benthic foraminifers uses Rose Bengal, a stain that reacts with both live and dead cytoplasm. CellTracker Green CMFDA is a fluorogenic probe causing live cells to fluoresce after proper incubation. To determine the more accurate viability method, we conducted a direct comparison of Rose Bengal staining with CellTracker Green labeling. Eight multicore tops were analyzed from Florida Margin (SE United States; 248\u2013751 m water depths), near Great Bahama Bank (259\u2013766 m), and off the Carolinas (SE United States; 220 and 920 m). On average, less than half the Rose Bengal\u2013stained foraminifera were actually living when collected. Thus, while Rose Bengal can significantly overestimate abundance, combined analyses of CellTracker Green and Rose Bengal can provide insights on population dynamics and effects of episodic events. Initial stable isotope analyses indicate that the CellTracker Green method does not significantly affect these important paleoceanographic proxies.", "keyphrases": ["foraminifera", "rose bengal", "celltracker green"]}
{"id": "10.1111/joa.13334", "title": "Myological reconstruction of the pelvic girdle and hind limb of the giant titanosaurian sauropod dinosaur Dreadnoughtus schrani", "abstract": "Osteological correlates preserve more readily than their soft tissue counterparts in the fossil record; therefore, they can more often provide insight into the soft tissue anatomy of the organism. These insights can in turn elucidate the biology of these extinct organisms. In this study, we reconstruct the pelvic girdle and hind limb musculature of the giant titanosaurian sauropod Dreadnoughtus schrani based on observations of osteological correlates and Extant Phylogenetic Bracket comparisons. Recovered fossils of Dreadnoughtus exhibit remarkably well\u2010preserved, well\u2010developed, and extensive muscle scars. Furthermore, this taxon is significantly larger bodied than any titanosaurian for which a myological reconstruction has previously been performed, rendering this contribution highly informative for the group. All 20 of the muscles investigated in this study are sufficiently well supported to enable reconstruction of at least one division, including reconstruction of the M. ischiocaudalis for the first time in a sauropod dinosaur. In total, 34 osteological correlates were identified on the pelvic girdle and hind limb remains of Dreadnoughtus, allowing the reconstruction of 14 muscles on the basis of Level I or Level II inferences (i.e., not Level I' or Level II' inferences). Comparisons among titanosaurians suggest widespread myological variation, yet potential phylogenetic and other paleobiologic patterns are often obscured by fragmentary preservation, infrequent myological studies, and lack of consensus on the phylogenetic placement of many taxa. However, a ventrolateral accessory process is present on the preacetabular lobe of the ilium in all of the largest titanosauriforms that preserve this skeletal element, suggesting that the presence of this process (representing the origin of the M. puboischiofemoralis internus part II) may be associated with extreme body size. By identifying such myological patterns among titanosauriforms, we can begin to address specific evolutionary and biomechanical questions related to their skeletal anatomy, how they were capable of leaving wide\u2010gauge trackways, and resulting locomotor attributes unique to this clade.", "keyphrases": ["pelvic girdle", "hind limb", "myological reconstruction"]}
{"id": "paleo.004100", "title": "Mass extinctions drove increased global faunal cosmopolitanism on the supercontinent Pangaea", "abstract": "Mass extinctions have profoundly impacted the evolution of life through not only reducing taxonomic diversity but also reshaping ecosystems and biogeographic patterns. In particular, they are considered to have driven increased biogeographic cosmopolitanism, but quantitative tests of this hypothesis are rare and have not explicitly incorporated information on evolutionary relationships. Here we quantify faunal cosmopolitanism using a phylogenetic network approach for 891 terrestrial vertebrate species spanning the late Permian through Early Jurassic. This key interval witnessed the Permian\u2013Triassic and Triassic\u2013Jurassic mass extinctions, the onset of fragmentation of the supercontinent Pangaea, and the origins of dinosaurs and many modern vertebrate groups. Our results recover significant increases in global faunal cosmopolitanism following both mass extinctions, driven mainly by new, widespread taxa, leading to homogenous \u2018disaster faunas\u2019. Cosmopolitanism subsequently declines in post-recovery communities. These shared patterns in both biotic crises suggest that mass extinctions have predictable influences on animal distribution and may shed light on biodiversity loss in extant ecosystems.", "keyphrases": ["faunal cosmopolitanism", "supercontinent pangaea", "mass extinction", "aftermath"]}
{"id": "10.1080/14772019.2011.566634", "title": "A restudy of the Burgess Shale (Cambrian) arthropod Emeraldella brocki and reassessment of its affinities", "abstract": "A restudy of the Burgess Shale arthropod Emeraldella brocki suggests novel interpretations of its morphology. We show that the morphology is more plesiomorphic than previously assumed, particularly regarding tagmosis. The cephalon probably only incorporates three limb-bearing postantennular segments. The trunk is not differentiated and consists of 12 tergite-bearing segments and a styliform telson. Limb structure is generally similar to that of other artiopods except for a tripartite exopod and a high degree of differentiation of podomere proportions along the body. A phylogenetic analysis of 20 fossil arthropod taxa based on 36 characters renders E. brocki as a basal taxon within a monophyletic group that comprises all artiopods included. Autapomorphies of this taxon are a filiform antennula and a bilobate exopod that carries lamellae proximally. Trilobites are nested within a group of artiopods sharing a pygidium. Agnostus pisiformis is retrieved as the sister taxon to the stem-lineage crustacean Oelandocaris oelandica, and both constitute the sister taxon of Artiopoda. \u2018Great appendage\u2019 arthropods, traditionally included in the Arachnomorpha, are retrieved as sister to the Crustacea sensu lato + Artiopoda clade, which contradicts the arachnomorph concept.", "keyphrases": ["restudy", "burgess shale", "arthropod emeraldella brocki"]}
{"id": "paleo.012358", "title": "A new theropod dinosaur from the early cretaceous (Barremian) of Cabo Espichel, Portugal: Implications for spinosaurid evolution", "abstract": "Spinosaurids are some of the most enigmatic Mesozoic theropod dinosaurs due to their unique adaptations to aquatic environments and their relative scarcity. Their taxonomy has proven to be especially problematic. Recent discoveries from Western Europe in general, specifically Iberia, provide some of the best specimens for the understanding of their phylogeny, leading to the description of the spinosaurid Vallibonavenatrix cani and the recognition of the Iberian dinosaur Camarillasaurus cirugedae as one of them. Portuguese associated spinosaurid remains (ML1190) from the Papo Seco Formation (early Barremian) were previously assigned to Baryonyx walkeri but new material recovered in 2020 along with new phylogenetic analyses suggests a different phylogenetic placement, making their revision necessary. Here we show that these remains are not attributable to Baryonyx walkeri, but to a new genus and species, Iberospinus natarioi, gen. et sp. nov. The new taxon is characterized by the presence of a single Meckelian foramen in the Meckelian sulcus, a straight profile of the ventral surface of the dentary and a distal thickening of the acromion process of the pubis between other characters. Iberospinus natarioi is recovered as a sister taxon of the clade formed by Baryonyx and Suchomimus, and outside Spinosaurinae when Vallibonaventrix cani is excluded from the analysis. The description of this taxon reinforces Iberia as a hotspot for spinosaur biodiversity, with several endemic taxa for the region. As expected for the clade, the dentary displays a highly vascularized neurovascular network. The morphometric analysis of parts of the skeleton (pedal phalanx and caudal vertebrae, among others) shows an intermediate condition between basal tetanurans and spinosaurines.", "keyphrases": ["theropod dinosaur", "barremian", "spinosaurid evolution"]}
{"id": "10.1111/j.1463-6395.2008.00364.x", "title": "Fossils provide better estimates of ancestral body size than do extant taxa in fishes", "abstract": "Albert, J.S., Johnson, D.M. and Knouft, J.H. 2009. Fossils provide better estimates of ancestral body size than do extant taxa in fishes. \u2014 Acta Zoologica (Stockholm) 90 (Suppl. 1): 308\u2010335 The use of fossils in studies of character evolution is an active area of research. Characters from fossils have been viewed as less informative or more subjective than comparable information from extant taxa. However, fossils are often the only known representatives of many higher taxa, including some of the earliest forms, and have been important in determining character polarity and filling morphological gaps. Here we evaluate the influence of fossils on the interpretation of character evolution by comparing estimates of ancestral body size in fishes (non-tetrapod craniates) from two large and previously unpublished datasets; a palaeontological dataset representing all principal clades from throughout the Phanerozoic, and a macroecological dataset for all 515 families of living (Recent) fishes. Ancestral size was estimated from phylogenetically based (i.e. parsimony) optimization methods. Ancestral size estimates obtained from analysis of extant fish families are five to eight times larger than estimates using fossil members of the same higher taxa. These disparities arise from differential survival of large-bodied members of early branching lineages, and are not statistical or taphonomic artefacts. Estimates of ancestral size obtained from a limited but judicious selection of fossil fish taxa are more accurate than estimates from a complete dataset of extant fishes. Journal: Acta Zoologica, 11th International Symposium on Early Vertebrates: Symposium volume", "keyphrases": ["ancestral body size", "extant taxa", "character evolution", "well estimate"]}
{"id": "paleo.009705", "title": "Consumption of crustaceans by megaherbivorous dinosaurs: dietary flexibility and dinosaur life history strategies", "abstract": "Large plant-eating dinosaurs are usually presumed to have been strictly herbivorous, because their derived teeth and jaws were capable of processing fibrous plant foods. This inferred feeding behavior offers a generalized view of dinosaur food habits, but rare direct fossil evidence of diet provides more nuanced insights into feeding behavior. Here we describe fossilized feces (coprolites) that demonstrate recurring consumption of crustaceans and rotted wood by large Late Cretaceous dinosaurs. These multi-liter coprolites from the Kaiparowits Formation are primarily composed of comminuted conifer wood tissues that were fungally degraded before ingestion. Thick fragments of laminar crustacean cuticle are scattered within the coprolite contents and suggest that the dinosaurian defecators consumed sizeable crustaceans that sheltered in rotting logs. The diet of decayed wood and crustaceans offered a substantial supply of plant polysaccharides, with added dividends of animal protein and calcium. Nevertheless, it is unlikely that the fossilized fecal residues depict year-round feeding habits. It is more reasonable to infer that these coprolites reflected seasonal dietary shifts\u2014possibly related to the dinosaurs\u2019 oviparous breeding activities. This surprising fossil evidence challenges conventional notions of herbivorous dinosaur diets and reveals a degree of dietary flexibility that is consistent with that of extant herbivorous birds.", "keyphrases": ["crustacean", "dietary flexibility", "consumption"]}
{"id": "10.1080/00288306.2004.9515080", "title": "Neogene stratigraphic architecture and tectonic evolution of Wanganui, King Country, and eastern Taranaki Basins, New Zealand", "abstract": "Abstract Analysis of the stratigraphic architecture of the fills of Wanganui, King Country, and eastern Taranaki Basins reveals the occurrence of five 2nd order Late Paleocene and Neogene sequences of tectonic origin. The oldest is the late Eocene\u2010Oligocene Te Kuiti Sequence, followed by the early\u2010early Miocene (Otaian) Mahoenui Sequence, followed by the late\u2010early Miocene (Altonian) Mokau Sequence, all three in King Country Basin. The fourth is the middle Miocene to early Pliocene Whangamomona Sequence, and the fifth is the middle Pliocene\u2010Pleistocene Rangitikei Sequence, both represented in the three basins. Higher order sequences (4th, 5th, 6th) with a eustatic origin occur particularly within the Whangamomona and Rangitikei Sequences, particularly those of 6th order with 41 000 yr periodicity. The base of each 2nd order sequence is marked by marine flooding and represents a discrete phase in basin development. The Te Kuiti Sequence accumulated in non\u2010marine and shelf environments, whereas the Mahoenui Sequence accumulated mostly at bathyal depths; no regressive deposits are evident, having been eroded during subsequent uplift. The Mokau Sequence comprises shoreface and non\u2010marine deposits including coal measures. The Whangamomona Sequence accumulated during extensive flooding of King Country Basin and collapse of the eastern margin of Taranaki Basin. It has a thin retrogressive part (Otunui Formation) and a thick progradational component (Mount Messenger to Matemateaonga Formations). The latter component represents the northward progradation of a continental margin wedge through Wanganui and King Country Basins. The Rangitikei Sequence is marked by extensive flooding at its base (Tangahoe Mudstone) and reflects the pull\u2010down of the main Wanganui Basin depocentre. This sequence comprises a second progradational margin wedge, which migrated on two fronts, one northward through Wanganui Basin into King Country Basin, and a second west of the Patea\u2010Tongaporutu High, through the Toru Trough into the Central and Northern Grabens of Taranaki Basin and on to the Western Platform as the Giant Foresets Formation, thereby building up the modern shelf and slope. All five sequences are erosionally truncated, with up to 2100 m of exhumation that affected much of central North Island. The Pliocene timing of the start of erosion, together with its pattern, point to long wavelength deformation of the crust driven from the upper mantle consequent upon migration of the late Miocene andesitic volcanic arc from northern Taranaki Basin into Taupo Volcanic Zone.", "keyphrases": ["stratigraphic architecture", "king country", "eastern taranaki basins"]}
{"id": "10.1098/rsbl.2007.0491", "title": "Giant claw reveals the largest ever arthropod", "abstract": "The fossil record has yielded various gigantic arthropods, in contrast to their diminutive proportions today. The recent discovery of a 46\u200acm long claw (chelicera) of the pterygotid eurypterid (\u2018sea scorpion\u2019) Jaekelopterus rhenaniae, from the Early Devonian Willwerath Lagerst\u00e4tte of Germany, reveals that this form attained a body length of approximately 2.5\u200am\u2014almost half a metre longer than previous estimates of the group, and the largest arthropod ever to have evolved. Gigantism in Late Palaeozoic arthropods is generally attributed to elevated atmospheric oxygen levels, but while this may be applicable to Carboniferous terrestrial taxa, gigantism among aquatic taxa is much more widespread and may be attributed to other extrinsic factors, including environmental resources, predation and competition. A phylogenetic analysis of the pterygotid clade reveals that Jaekelopterus is sister-taxon to the genus Acutiramus, and is among the most derived members of the pterygotids, in contrast to earlier suggestions.", "keyphrases": ["claw", "pterygotid", "jaekelopterus rhenaniae", "apex predator"]}
{"id": "paleo.008423", "title": "Census of Dinosaur Skin Reveals Lithology May Not Be the Most Important Factor in Increased Preservation of Hadrosaurid Skin", "abstract": "A global census of published records of dinosaur skin from the Mesozoic, cross-referenced against a more detailed lithological dataset from the Maastrichtian of North America, clarifies why most examples of fossilized dinosaur skin come from hadrosaurids. Globally, more published specimens of hadrosaurids exhibit preserved skin than any other major clade of dinosaur. North American Maastrichtian hadrosaurid fossils are 31 times more likely to have skin preserved than coeval dinosaur remains. This does not arise from collection methodology, the large population size of hadrosaurids, or the gross lithology of their depositional environment. The reason that so many hadrosaurid fossils have skin is still elusive, but was likely something intrinsic to hadrosaurids that originated early on in the clade, perhaps the possession of tougher or thicker skin. The database of published examples of fossilized dinosaur skin assembled here will assist the continued development of a much needed common terminology and taxonomic framework for dinosaur skin.", "keyphrases": ["dinosaur skin", "lithology", "census"]}
{"id": "10.1098/rspb.2009.2005", "title": "Developmental palaeontology in synapsids: the fossil record of ontogeny in mammals and their closest relatives", "abstract": "The study of fossilized ontogenies in mammals is mostly restricted to postnatal and late stages of growth, but nevertheless can deliver great insights into life history and evolutionary mechanisms affecting all aspects of development. Fossils provide evidence of developmental plasticity determined by ecological factors, as when allometric relations are modified in species which invaded a new space with a very different selection regime. This is the case of dwarfing and gigantism evolution in islands. Skeletochronological studies are restricted to the examination of growth marks mostly in the cement and dentine of teeth and can provide absolute age estimates. These, together with dental replacement data considered in a phylogenetic context, provide life-history information such as maturation time and longevity. Palaeohistology and dental replacement data document the more or less gradual but also convergent evolution of mammalian growth features during early synapsid evolution. Adult phenotypes of extinct mammals can inform developmental processes by showing a combination of features or levels of integration unrecorded in living species. Some adult features such as vertebral number, easily recorded in fossils, provide indirect information about somitogenesis and hox-gene expression boundaries. Developmental palaeontology is relevant for the discourse of ecological developmental biology, an area of research where features of growth and variation are fundamental and accessible among fossil mammals.", "keyphrases": ["ontogeny", "developmental biology", "developmental palaeontology"]}
{"id": "10.5252/az2009n1a2", "title": "Hallan \u00c7emi Tepesi: High-ranked Game Exploitation alongside Intensive Seed Processing at the Epipaleolithic-Neolithic Transition in Southeastern Turkey", "abstract": "Starkovich B.M. & Stiner M.C. 2009. \u2014 Hallan Cemi Tepesi: High-ranked Game Exploitation alongside Intensive Seed Processing at the Epipaleolithic-Neolithic Transition in Southeastern Turkey. Anthropozoologica 44(1): 41-61. ABSTRACTS Faunal evidence from Hallan \u00c7emi Tepesi in southeastern Turkey reveals important similarities and differences in subsistence patterns when compared to the Levant at the time of the Epipaleolithic-Neolithic transition. Possible diet breadth expansion is examined at Hallan \u00c7emi based on prey species and biomass composition, body part analysis, age profiles, and carcass processing patterns. The occupants of Hallan \u00c7emi hunted a wide range of animals, including wild sheep and goats, pigs, red deer, and tortoises. Low-ranked, fast-moving small game animals such as hares and avian fauna are comparatively rare. Small game use at Hallan \u00c7emi resembles patterns observed in some late Natufian sites, but there is focused exploitation of ungulates at Hallan \u00c7emi. The site presents a seemingly contradictory pairing of a meat diet composed of high-ranked animal resources and intensive plant seed processing. Also supporting the overall picture of high-ranked animal exploitation are transport biases that favored the meatiest portions of ungulate carcasses, particularly the upper front limb region. Potential explanations for the contrasting meat and plant diet patterns must consider expanding diet breadth in response to demographic packing (expressed mainly in terms of plant exploitation) and display behaviors that emphasized large game but not other parts of the food supply.", "keyphrases": ["high-ranked game exploitation", "intensive seed processing", "southeastern turkey"]}
{"id": "10.4436/JASS.95017", "title": "Form and function in the Lower Palaeolithic: history, progress, and continued relevance.", "abstract": "Percussively flaked stone artefacts constitute a major source of evidence relating to hominin behavioural strategies and are, essentially, a product or byproduct of a past individual's decision to create a tool with respect to some broader goal. Moreover, it has long been noted that both differences and recurrent regularities exist within and between Palaeolithic stone artefact forms. Accordingly, archaeologists have frequently drawn links between form and functionality, with functional objectives and performance often being regarded consequential to a stone tool's morphological properties. Despite these factors, extensive reviews of the related concepts of form and function with respect to the Lower Palaeolithic remain surprisingly sparse. We attempt to redress this issue. First we stress the historical place of form-function concepts, and their role in establishing basic ideas that echo to this day. We then highlight methodological and conceptual progress in determining artefactual function in more recent years. Thereafter, we evaluate four specific issues that are of direct consequence for evaluating the ongoing relevance of form-function concepts, especially with respect to their relevance for understanding human evolution more generally. Our discussion highlights specifically how recent developments have been able to build on a long historical legacy, and demonstrate that direct, indirect, experimental, and evolutionary perspectives intersect in crucial ways, with each providing specific but essential insights for ongoing questions. We conclude by emphasising that our understanding of these issues and their interaction, has been, and will be, essential to accurately interpret the Lower Palaeolithic archaeological record, tool-form related behaviours of Lower Palaeolithic hominins, and their consequences for (and relationship to) wider questions of human evolution.", "keyphrases": ["lower palaeolithic", "progress", "relevance"]}
{"id": "paleo.002944", "title": "Cyclic environmental changes during the Early Toarcian at the Mochras Farm Borehole (Wales): a variable response of the foraminiferal community", "abstract": "Cyclostratigraphical analysis of the foraminiferal assemblages from the Early Toarcian at the Mochras Farm Borehole (Wales) was conducted in order to evaluate the incidence of cyclic palaeoenvironmental changes on the foraminiferal community. Different variables such as type of morphogroup, evolutionary strategy, habitat, particular taxa, diversity and abundance were studied using the Lomb-Scargle periodogram implemented in the computer program SLOMBS. A well-developed cyclostratigraphical pattern is recognized, with the presence of several cycles (in metres) at 3.", "keyphrases": ["early toarcian", "mochras farm borehole", "foraminiferal community"]}
{"id": "paleo.010998", "title": "LUCApedia: a database for the study of ancient life", "abstract": "Organisms represented by the root of the universal evolutionary tree were most likely complex cells with a sophisticated protein translation system and a DNA genome encoding hundreds of genes. The growth of bioinformatics data from taxonomically diverse organisms has made it possible to infer the likely properties of early life in greater detail. Here we present LUCApedia, (http://eeb.princeton.edu/lucapedia), a unified framework for simultaneously evaluating multiple data sets related to the Last Universal Common Ancestor (LUCA) and its predecessors. This unification is achieved by mapping eleven such data sets onto UniProt, KEGG and BioCyc IDs. LUCApedia may be used to rapidly acquire evidence that a certain gene or set of genes is ancient, to examine the early evolution of metabolic pathways, or to test specific hypotheses related to ancient life by corroborating them against the rest of the database.", "keyphrases": ["database", "ancient life", "luca", "lucapedia"]}
{"id": "10.1029/2011PA002143", "title": "Effect of the deepening of the Tasman Gateway on the global ocean", "abstract": "[1]\u00a0We examine the effect of the deepening of the Tasman Seaway at the end of the Eocene in a climate model with realistic late Eocene bathymetry and winds. For this, we have constructed an Eocene numerical model based on the University of Victoria climate model with wind forcing derived from a fully coupled Eocene simulation. The model climate state is characterized by an oceanic meridional overturning circulation (MOC) involving Southern Hemisphere sinking and a northward atmospheric moisture transport across the equator. The deepening of the Tasman Seaway in the presence of an open Drake Passage and the associated establishment of the Antarctic Circumpolar Current (ACC) have a limited climatic impact on Antarctica. Nonetheless, the Antarctic deep sinking regions cool sufficiently to lead to a global deep ocean cooling of 3\u00b0C. No initiation of Northern Component Water is found, indicating that this may require the development of a more mature ACC. Previous studies suggest that the Ross Sea gyre cools the east coast of Australia, and expected the deepening of the Tasman Seaway to lead to a warming east of Australia due to the introduction of warmer water from the Australo-Antarctic Gulf. We here find that this warming is limited to close to the Australian coast, and that widespread cooling prevails further off shore.", "keyphrases": ["deepening", "ocean", "circulation", "australia"]}
{"id": "paleo.004917", "title": "Neuroanatomy of the nodosaurid Struthiosaurus austriacus (Dinosauria: Thyreophora) supports potential ecological differentiations within Ankylosauria", "abstract": "Nodosauridae is a group of thyreophoran dinosaurs characterized by a collar of prominent osteoderms. In comparison to its sister group, the often club-tailed ankylosaurids, a different lifestyle of nodosaurids could be assumed based on their neuroanatomy and weaponry, e.g., regarding applied defensive strategies. The holotype of the nodosaurid Struthiosaurus austriacus consists of a single partial braincase from the Late Cretaceous of Austria. Since neuroanatomy is considered to be associated with ecological tendencies, we created digital models of the braincase based on micro-CT data. The cranial endocast of S. austriacus generally resembles those of its relatives. A network of vascular canals surrounding the brain cavity further supports special thermoregulatory adaptations within Ankylosauria. The horizontal orientation of the lateral semicircular canal independently confirms previous appraisals of head posture for S. austriacus and, hence, strengthens the usage of the LSC as proxy for habitual head posture in fossil tetrapods. The short anterior and angular lateral semicircular canals, combined with the relatively shortest dinosaurian cochlear duct known so far and the lack of a floccular recess suggest a rather inert lifestyle without the necessity of sophisticated senses for equilibrium and hearing in S. austriacus. These observations agree with an animal that adapted to a comparatively inactive lifestyle with limited social interactions.", "keyphrases": ["nodosaurid struthiosaurus austriacus", "ankylosauria", "neuroanatomy"]}
{"id": "10.1144/jgs2018-053", "title": "The Schilfsandstein and its flora; arguments for a humid mid-Carnian episode?", "abstract": "Recently intensified research on the mid-Carnian episode stimulated discussions about the mid-Carnian climate and a supposed humid climate shift. This basin-scale study on the Schilfsandstein, the type-example of the mid-Carnian episode, applied sedimentological, palynological and palaeobotanical proxies of the palaeoclimate to a large dataset of cored wells and outcrops. The results demonstrate the primary control of circum-Tethyan eustatic cycles on the Central European Basin where transgressions contributed to basin-scale facies shifts. The palaeoclimate proxies point to a uniform arid to semi-arid Carnian climate with low chemical weathering and high evaporation. Consequently, transgressions into the Central European Basin led to increased evaporation forcing the hydrological cycle. The increased runoff from source areas resulted in high-groundwater stages on lowlands characterized by hydromorphic palaeosols and intrazonal vegetation with hygrophytic elements. During lowstands, reduced evaporation and runoff led to increased drainage and desiccation of lowlands characterized by formation of vertisols, calcisols and gypsisols and zonal vegetation with xerophytic elements. The proposed model of sea-level control on the hydrological cycle integrates coeval and subsequent occurrences of wet and dry lowlands, hydromorphic and well-drained palaeosols, and intrazonal and zonal vegetations. Thus, the Schilfsandstein does not provide arguments for a humid mid-Carnian episode. Supplementary material: Datasets of Palynomorph Eco Group (PEG) and Macroplant Eco Group (MEG) analyses are available at https://doi.org/10.6084/m9.figshare.c.4182593", "keyphrases": ["schilfsandstein", "argument", "humid mid-carnian episode"]}
{"id": "10.1111/pala.12456", "title": "Exceptional preservation requires fast biodegradation: thylacocephalan specimens from La Voulte\u2010sur\u2010Rh\u00f4ne (Callovian, Jurassic, France)", "abstract": "Konservat\u2010Lagerst\u00e4tten are seen as snapshots of past biodiversity for a given location and time. However, processes leading to the exceptional morphological preservation of fossils in these deposits remain incompletely understood. This results in a deficient assessment of taphonomic biases and limits the robustness/relevance of palaeobiological reconstructions. Here, we report the mineralogical characterization of crustacean fossils preserved within carbonate\u2010rich concretions from the Jurassic Konservat\u2010Lagerst\u00e4tte of La Voulte\u2010sur\u2010Rh\u00f4ne (Ard\u00e8che, France). The combination of SEM\u2010EDS, TEM, synchrotron\u2010based XRF, XRD and XANES allows the mineralogical phases composing these fossils (i.e. fluorapatite, Fe\u2010sulfides (pyrite, pyrrhotite) and Mg\u2010calcite) and the surrounding matrix (i.e. Mg\u2010calcite, clays and detrital silicates) to be identified. Fluorapatite and pyrite (and pyrrhotite) precipitated during decay under anoxic conditions, replacing delicate organic structures and preserving anatomical details. These mineral structures were subsequently consolidated by a Mg\u2010calcite cement. Of note, histologically similar tissues were replaced by the same mineral phases, confirming that fossilization (in La Voulte) occurred rapidly enough to be influenced by tissue composition. Altogether, the present study shows that exceptional preservation requires fast biodegradation, thereby confirming recent experimental evidence.", "keyphrases": ["fast biodegradation", "france", "exceptional preservation"]}
{"id": "10.1126/science.1201477", "title": "Paleoindian Seafaring, Maritime Technologies, and Coastal Foraging on California\u2019s Channel Islands", "abstract": "Archaeological sites reveal a variety of tools used to hunt marine birds, mammals, and fish 12,000 years ago. Three archaeological sites on California\u2019s Channel Islands show that Paleoindians relied heavily on marine resources. The Paleocoastal sites, dated between ~12,200 and 11,200 years ago, contain numerous stemmed projectile points and crescents associated with a variety of marine and aquatic faunal remains. At site CA-SRI-512 on Santa Rosa Island, Paleocoastal peoples used such tools to capture geese, cormorants, and other birds, along with marine mammals and finfish. At Cardwell Bluffs on San Miguel Island, Paleocoastal peoples collected local chert cobbles, worked them into bifaces and projectile points, and discarded thousands of marine shells. With bifacial technologies similar to those seen in Western Pluvial Lakes Tradition assemblages of western North America, the sites provide evidence for seafaring and island colonization by Paleoindians with a diversified maritime economy.", "keyphrases": ["california", "channel islands", "archaeological site", "crescent", "western north america"]}
{"id": "paleo.011568", "title": "High-Resolution Coproecology: Using Coprolites to Reconstruct the Habits and Habitats of New Zealand\u2019s Extinct Upland Moa (Megalapteryx didinus)", "abstract": "Knowledge about the diet and ecology of extinct herbivores has important implications for understanding the evolution of plant defence structures, establishing the influences of herbivory on past plant community structure and composition, and identifying pollination and seed dispersal syndromes. The flightless ratite moa (Aves: Dinornithiformes) were New Zealand\u2019s largest herbivores prior to their extinction soon after initial human settlement. Here we contribute to the knowledge of moa diet and ecology by reporting the results of a multidisciplinary study of 35 coprolites from a subalpine cave (Euphrates Cave) on the South Island of New Zealand. Ancient DNA analysis and radiocarbon dating revealed the coprolites were deposited by the extinct upland moa (Megalapteryx didinus), and span from at least 6,368\u00b131 until 694\u00b130 14C years BP; the approximate time of their extinction. Using pollen, plant macrofossil, and ancient DNA analyses, we identified at least 67 plant taxa from the coprolites, including the first evidence that moa fed on the nectar-rich flowers of New Zealand flax (Phormium) and tree fuchsia (Fuchsia excorticata). The plant assemblage from the coprolites reflects a highly-generalist feeding ecology for upland moa, including browsing and grazing across the full range of locally available habitats (spanning southern beech (Nothofagus) forest to tussock (Chionochloa) grassland). Intact seeds in the coprolites indicate that upland moa may have been important dispersal agents for several plant taxa. Plant taxa with putative anti-browse adaptations were also identified in the coprolites. Clusters of coprolites (based on pollen assemblages, moa haplotypes, and radiocarbon dates), probably reflect specimens deposited at the same time by individual birds, and reveal the necessity of suitably large sample sizes in coprolite studies to overcome potential biases in diet interpretation.", "keyphrases": ["coprolite", "new zealand", "extinct upland moa"]}
{"id": "paleo.011107", "title": "Application of a robotic THz imaging system for sub-surface analysis of ancient human remains", "abstract": "We used a robotic-based THz imaging system to investigate the sub-surface structure of an artificially mummified ancient Egyptian human left hand. The results obtained are compared to the results of a conventional CT and a micro-CT scan. Using such a robotic THz system promises new insights into the sub-surface structure of human remains. The depth resolution of the THz images exceeds the resolution of a conventional CT scan and is comparable with a micro-CT scan. The advantage of THz measurements over micro-CT scans is the fact that even comparatively large samples, like complete bodies, can be scanned. These would not fit into a conventional micro-CT scanner.", "keyphrases": ["thz imaging system", "human remain", "depth resolution", "complete body", "conventional micro-ct scanner"]}
{"id": "10.1080/03115518.2013.753767", "title": "The first discovery of anomalocaridid appendages from the Balang Formation (Cambrian Series 2) in Hunan, China", "abstract": "Liu, Q., 2013. The first discovery of anomalocaridid appendages from the Balang Formation (Cambrian Series 2) in Hunan, China. Alcheringa 37, 1\u20136. ISSN 0311-5518. This study reports the first discovery of anomalocaridid appendages from the lower part of the Balang Formation (Cambrian Series 2) in Paiwu, northwestern Hunan Province, China. The material includes Anomalocaris sp., a representative of a genus recognized in most of the major Cambrian Lagerst\u00e4tten, and Peytoia sp. cf. P. nathorsti Walcott, 1911, representing the first record of the \u2018Appendage F\u2019-type (Hurdia/Peytoia-type) frontal appendages from China. These new discoveries increase our knowledge of the diversity of anomalocaridids in China.", "keyphrases": ["anomalocaridid appendage", "balang formation", "cambrian series"]}
{"id": "10.1080/03115518.2011.533972", "title": "Microdictyon plates from the lower Cambrian Ajax Limestone of South Australia: Implications for species taxonomy and diversity", "abstract": "A small assemblage of isolated Microdictyon plates is described from the lower Cambrian Ajax Limestone, Mt Scott Range (Flinders Ranges), South Australia. Microdictyon plates are primarily known from single, isolated, perforated phosphatic sclerites; only one species (M. sinicum) from the Chengjiang Lagerst\u00e4tte is known from soft-bodied preservation of the complete organism. The isolated plates from South Australia display a wide range of morphologies potentially reflecting: 1, considerable diversification within the group at this time; 2, extensive intraspecific morphological variation; 3, different plate morphotypes along the trunk of the animal; or 4, significant ontogenetic variation in successive growth stages. The South Australian specimens are similar to several individual sclerites described from other Cambrian palaeocontinents, but appear closest to faunas described from South China. Problems associated with the taxonomy of isolated Microdictyon plates are discussed, including the lack of knowledge associated with intraspecific and/or ontogenetic variability and how individual plate morphology may relate to size or relative position along the length of the complete organism.", "keyphrases": ["cambrian ajax limestone", "south australia", "microdictyon plate"]}
{"id": "10.1080/02724634.2011.550363", "title": "A New Pachypleurosaur (Reptilia: Sauropterygia) from the Lower Middle Triassic of Southwestern China and the Phylogenetic Relationships of Chinese Pachypleurosaurs", "abstract": "ABSTRACT \n A new genus and species of Pachypleurosauria, Dianopachysaurus dingi, gen. et sp. nov., from a recently discovered Middle Triassic Lagerst\u00e4tte in the Anisian Guanling Formation of Yunnan Province is described. The monophyly of Pachypleurosauria, including all potential Chinese pachypleurosaurs in this study, is supported by the rigorous cladistic analysis conducted here. Phylogenetic relationships of Chinese pachypleurosaurs are clarified. Wumengosaurus occupies the most basal position within Pachypleurosauria. Keichousaurus and Dianopachysaurus form the monophyletic Keichousauridae that is the sister group of all European pachypleurosaurs. Our cladistic analysis also supports a previously proposed paleobiogeographic hypothesis of an eastern Tethyan origin of pachypleurosaurs and their migration into the western Tethyan faunal province. The existence of a long ghost lineage as required by the paleobiogeographic hypothesis is greatly shortened by the discovery of Dianopachysaurus.", "keyphrases": ["pachypleurosaur", "phylogenetic relationship", "keichousaurus", "keichousauridae"]}
{"id": "10.1080/14614103.2018.1486274", "title": "Reconstruction of Caprine Management and Landscape Use Through Dental Microwear Analysis: The Case of the Iron Age Site of El Tur\u00f3 de la Font de la Canya (Barcelona, Spain)", "abstract": "ABSTRACT This paper presents the results of a pilot study using dental microwear analysis on 23 sheep and goat teeth dated to the 6th century BC from the Iron Age site of El Tur\u00f3 Font de la Canya (Barcelona, Spain). This study aimed to reconstruct livestock management practices and landscape use. The dental microwear pattern indicates that sheep and goats could have been grazing in the same area where vegetation was composed of shrubs, bushes and non-graminaceous plants on an eroded landscape, although additional supplies of fodder cannot be excluded. This scenario is compatible with the archaeological and palaeoenvironmental data which suggest a possibly increased territoriality, land degradation and an increase of woodland clearance during Iron Age in the North-east of the Iberian Peninsula. Furthermore, we applied two recent microwear approaches which provide more information about mortality events and the possibility of distinguishing between an intensive and extensive management. This paper demonstrates how this method can be used to better understand animal husbandry practices and landscape use in Late Prehistory.", "keyphrases": ["landscape use", "dental microwear analysis", "iron age site"]}
{"id": "paleo.005097", "title": "The world\u2019s smallest owl, the earliest unambiguous charadriiform bird, and other avian remains from the early Eocene Nanjemoy Formation of Virginia (USA)", "abstract": "New avian remains from the early Eocene Nanjemoy Formation in Virginia (USA) are described. The material stems from the Fisher/Sullivan site and consists of isolated bones. These belong to at least 13 species, most of which have not yet been reported from the Nanjemoy Formation. The fossil material includes the oldest unambiguous record of a charadriiform bird and a new species of protostrigid owl, which represents the smallest known owl species. Other specimens are tentatively assigned to the Procellariiformes, the suliform Fregatidae, the gruiform Messelornithidae, and the apodiform Eocypselidae. A complete and well-preserved tarsometatarsus of the psittacopasserine Halcyornithidae provides new data on the osteology of these enigmatic birds, and a distal tibiotarsus is tentatively assigned to the Trogoniformes. The identification of a number of fossils is uncertain, with the bones showing similarities to Threskiornithidae and extinct taxa from the early Eocene of Europe (Microena, Morsoravis). All bird fossils from the Nanjemoy Formation are threedimensionally preserved and, therefore, allow a detailed assessment of osteological features, which complements studies of compression fossils from lagersta \u00a8tten-type fossil sites.", "keyphrases": ["charadriiform bird", "eocene nanjemoy formation", "usa"]}
{"id": "10.1017/s0022336000032145", "title": "Trilobite malformations and the fossil record of behavioral asymmetry", "abstract": "Malformations of trilobites are classified as healed injuries, teratological conditions, and pathological conditions. An improved method of recognizing such malformations combines information about the conditions under which cell injury can occur, the processes by which animal tissues react to injury, and trilobite morphology. Study of healed injuries of polymeroid trilobites shows that injuries attributed to sublethal predation tend to be most commonly preserved on the pleural lobes, the posterior half of the body, and the right side. Statistically significant differences in the number of predation scars between the right and left sides is interpreted as evidence of right-left behavioral asymmetry in some predators of trilobites or the trilobites themselves. Asymmetrical, or lateralized, behavior in present-day animals is one manifestation of handedness, and is usually related to a functional lateralization of the nervous system. Evidence of behavioral lateralization in some Paleozoic predators or prey suggests that those organisms also possessed lateralized nervous systems. Right-left differences in preserved predation scars on trilobites date from the Early Cambrian (Olenellus Zone), and are the oldest known evidence of behavioral asymmetry in the fossil record. Other examples of structural or behavioral asymmetry from the fossil record of animals are cited. Lateralization is recognized in representatives of the Arthropoda, Annelida, Bryozoa, Echinodermata, Cnidaria, Mollusca, Chordata, and Conodonta, and in trace fossils.", "keyphrases": ["malformation", "behavioral asymmetry", "injury", "predation", "trilobite"]}
{"id": "paleo.011944", "title": "Sauropodomorph evolution across the Triassic\u2013Jurassic boundary: body size, locomotion, and their influence on morphological disparity", "abstract": "Sauropodomorph dinosaurs were the dominant medium to large-sized herbivores of most Mesozoic continental ecosystems, being characterized by their long necks and reaching a size unparalleled by other terrestrial animals (> 60 tonnes). Our study of morphological disparity across the entire skeleton shows that during the Late Triassic the oldest known sauropodomorphs occupied a small region of morphospace, subsequently diversifying both taxonomically and ecologically, and shifting to a different and broader region of the morphospace. After the Triassic\u2013Jurassic boundary event, there are no substancial changes in sauropodomorph morphospace occupation. Almost all Jurassic sauropodomorph clades stem from ghost lineages that cross the Triassic\u2013Jurassic boundary, indicating that variations after the extinction were more related to changes of pre-existing lineages (massospondylids, non-gravisaurian sauropodiforms) rather than the emergence of distinct clades or body plans. Modifications in the locomotion (bipedal to quadrupedal) and the successive increase in body mass seem to be the main attributes driving sauropodomorph morphospace distribution during the Late Triassic and earliest Jurassic. The extinction of all non-sauropod sauropodomorphs by the Toarcian and the subsequent diversification of gravisaurian sauropods represent a second expansion of the sauropodomorph morphospace, representing the onset of the flourishing of these megaherbivores that subsequently dominated in Middle and Late Jurassic terrestrial assemblages.", "keyphrases": ["triassic\u2013jurassic boundary", "body size", "morphological disparity", "sauropod"]}
{"id": "paleo.009030", "title": "Growing up Tyrannosaurus rex: Osteohistology refutes the pygmy \u201cNanotyrannus\u201d and supports ontogenetic niche partitioning in juvenile Tyrannosaurus", "abstract": "Tyrannosaurus rex dominated its ecosystem by singularly exploiting the roles of mid- and large-sized carnivore as it grew up. Despite its iconic status as the king of dinosaurs, Tyrannosaurus rex biology is incompletely understood. Here, we examine femur and tibia bone microstructure from two half-grown T. rex specimens, permitting the assessments of age, growth rate, and maturity necessary for investigating the early life history of this giant theropod. Osteohistology reveals these were immature individuals 13 to 15 years of age, exhibiting growth rates similar to extant birds and mammals, and that annual growth was dependent on resource abundance. Together, our results support the synonomization of \u201cNanotyrannus\u201d into Tyrannosaurus and fail to support the hypothesized presence of a sympatric tyrannosaurid species of markedly smaller adult body size. Our independent data contribute to mounting evidence for a rapid shift in body size associated with ontogenetic niche partitioning late in T. rex ontogeny and suggest that this species singularly exploited mid- to large-sized theropod niches at the end of the Cretaceous.", "keyphrases": ["tyrannosaurus", "osteohistology", "ontogenetic niche"]}
{"id": "10.1002/2017GL073936", "title": "Connecting Antarctic sea ice to deep-ocean circulation in modern and glacial climate simulations: SEA ICE AND GLACIAL AMOC", "abstract": "Antarctic sea-ice formation plays a key role in shaping the abyssal overturning circulation and stratification in all ocean basins, by driving surface buoyancy loss through the associated brine rejection. Changes in Antarctic sea ice have therefore been suggested as drivers of major glacial-interglacial ocean circulation rearrangements. Here, the relationship between Antarctic sea ice, buoyancy loss, deep-ocean stratification, and overturning circulation is investigated in Last Glacial Maximum and preindustrial simulations from the Paleoclimate Modelling Intercomparison Project (PMIP). The simulations show substantial inter-model differences in their representation of the glacial deep-ocean state and circulation, which is often at odds with the geological evidence. We argue that these apparent inconsistencies can largely be attributed to differing (and likely insufficient) Antarctic sea-ice formation. Discrepancies can be further amplified by short integration times. Deep-ocean equilibration and sea-ice representation should, therefore, be carefully evaluated in the forthcoming PMIP4 simulations.", "keyphrases": ["antarctic sea ice", "circulation", "simulation"]}
{"id": "10.1080/02724634.2017.1396539", "title": "The Anatomy of Teleocrater rhadinus, an Early Avemetatarsalian from the Lower Portion of the Lifua Member of the Manda Beds (Middle Triassic)", "abstract": "ABSTRACT Bird-line archosaurs (= Avemetatarsalia, the clade containing birds, dinosaurs, pterosaurs, and their kin) originated in the Triassic Period. However, the earliest evolution of this group is poorly documented because fossils are extremely rare and consist mostly of postcrania. Here, we document the osteology of Teleocrater rhadinus, an early avemetatarsalian from the lower portion of the Middle Triassic Lifua Member of the Manda Beds of the Ruhuhu Basin, southwestern Tanzania. Material of Teleocrater rhadinus includes the holotype partial skeleton comprising a single individual, including cervical, trunk, and caudal vertebrae, pectoral, pelvic, forelimb, and hind limb material, and referred specimens representing parts (skull elements, vertebrae, pectoral, pelvic, and limb elements) of at least three other individuals collected from a bonebed. Character states of the skull elements, vertebrae, girdles, and limbs indicate that Teleocrater rhadinus represents the first documented non-ornithodiran avemetatarsalian known from well-preserved, associated material. Furthermore, Teleocrater rhadinus forms part of a newly recognized clade, Aphanosauria, which also contains formerly enigmatic archosaur taxa from across Pangea, including Dongusuchus efremovi from the Middle Triassic of Russia, Yarasuchus deccanensis from the Middle Triassic of India, and Spondylosoma absconditum from the ?Middle Triassic of Brazil. This new clade and other new discoveries from the Middle to Late Triassic elucidate the sequence of character acquisitions at the base of Avemetatarsalia and fill a crucial gap in the understanding of the anatomical transformations that enabled dinosaurs to flourish later in the Mesozoic.", "keyphrases": ["teleocrater rhadinus", "avemetatarsalian", "middle triassic"]}
{"id": "paleo.008159", "title": "Nearctic Pleistocene ungulates from the Pampean region (Argentina) in the historical collections of Santiago Roth in Switzerland: an overview", "abstract": "Nearctic ungulates such as artiodactyls, perissodactyls, and proboscideans arrived in South America during the Great American Biotic Interchange. Among them are camelids, cervids, tayassuids, equids, tapirids and gomphotherids. A historical collection of Nearctic ungulates from Pleistocene deposits of the Pampean region in Argentina is here studied and described. The collection consists of specimens collected by Santiago Roth in the nineteenth century and brought to Europe, where they are housed in the paleontological collections of the University of Zurich and the Natural History Museum of Geneva. Among the taxa reported here are Notiomastodon platensis, Lama guanicoe, Hemiauchenia paradoxa, Tayassu pecari, Morenelaphus sp., Hippidion cf. H. principale, Equus cf. E. neogeus, and other indeterminate gomphotherids, camelids, tayassuids, cervids, and equids. The exact stratigraphic position of these fossils collected more than 130 years ago is in many cases uncertain. The historical collection is still relevant for taxonomic studies and for offering new insights into palaeobiogeography and palaeobiology of mammalian fauna of the region during the Pleistocene. Keywords Cenozoic, South America, Fossils, Mammals, Great American biotic interchange\nLos ungulados ne\u00e1rticos como los artiod\u00e1ctilos, perisod\u00e1ctilos y los probosc\u00eddeos llegaron a Am\u00e9rica del Sur durante el Gran Intercambio Bi\u00f3tico Americano. Entre ellos se encuentran los cam\u00e9lidos, c\u00e9rvidos, tayasuidos, \u00e9quidos, tap\u00edridos y gonfot\u00e9ridos. Aqu\u00ed se estudia y describe una colecci\u00f3n hist\u00f3rica de ungulados ne\u00e1rticos procedentes de dep\u00f3sitos pleistocenos de la regi\u00f3n pampeana en Argentina. La colecci\u00f3n consta de espec\u00edmenes que fueron recolectados por Santiago Roth durante el siglo XIX, llev\u00e1ndolos a Europa donde se encuentran depositados en las colecciones", "keyphrases": ["pleistocene", "ungulate", "pampean region", "historical collection"]}
{"id": "paleo.001072", "title": "Low palaeoelevation of the northern Lhasa terrane during late Eocene: Fossil foraminifera and stable isotope evidence from the Gerze Basin", "abstract": "The Lhasa terrane is a key region for understanding the paleoelevation of the southern Tibetan Plateau after India-Asia collision. The Gerze Basin, located in the northern part of the Lhasa terrane, is a shortening-related basin. We discovered Lagena laevis (Bandy) fossils in upper Eocene strata of the Gerze Basin. This type of foraminifera is associated with lagoon and estuarine environments, indicating that the northern part of the Lhasa terrane was near sea level during the late Eocene. We speculate that these foraminifera were transported inland by storm surges to low elevation freshwater lakes during times of marine transgressions. This inference is consistent with the relatively positive \u03b418O values in carbonate from the same deposits that indicate low palaeoelevations close to sea level. Considering the palaeoelevation results from the nearby Oligocene basins at a similar latitude and the volcanic history of the Lhasa terrane, we infer that large-magnitude surface uplift of the northern Lhasa terrane occurred between late Eocene and late Oligocene time.", "keyphrases": ["palaeoelevation", "northern lhasa terrane", "late eocene"]}
{"id": "10.1017/S0022336000038749", "title": "The petrosal and inner ear of Herpetocetus sp. (Mammalia: Cetacea) and their implications for the phylogeny and hearing of archaic mysticetes", "abstract": "This paper describes the petrosal (periotic) and the inner ear of Herpetocetus sp., an archaic mysticete whale (Mysticeti, Mammalia) from the Yorktown Formation (Pliocene) of North Carolina, USA. Parsimony analysis of 28 petrosal characters of Herpetocetus sp. and 11 other cetacean taxa supports the monophyly of mysticetes and the division of odontocetes and mysticetes. The in-group taxa of this analysis are: Herpetocetus, Parietobalaena, Pelocetus, Balaenidae, Eschrichtius, and Balaenopteridae. Odontocetes and the archaeocete Zygorhiza were used as successive outgroups to root phylogenetic trees and to establish character polarities. Among the modern mysticetes, the Balaenopteridae (rorquals) and the Eschrichtiidae (gray whales) are more closely related to each other than either is to the Balaenidae (bowhead and right whales). Several Miocene \u201ccetotheriid\u201d mysticetes and balaenids share some resemblance in the petrosal, suggesting their affinities. Quantitative information of the inner ear of Herpetocetus sp. was obtained by serial sectioning and computer graphic reconstruction. Herpetocetus sp. is much less developed than odontocetes in the cochlear structures that are crucial for high frequency hearing. Some cochlear structures in this fossil mysticete resemble more closely the non-echolocating modern mysticetes than early fossil toothed whales, indicating a possible specialization in low frequency hearing. This suggests that the archaic mysticetes of the Miocene and Pliocene did not have high frequency hearing necessary for echolocation. Herpetocetus sp. is similar to modern mysticetes but different from odontocetes in the spherical shape of the vestibule.", "keyphrases": ["petrosal", "inner ear", "mammalia"]}
{"id": "paleo.007426", "title": "The geography of body size in cuttlefishes (Cephalopoda, Sepiidae)", "abstract": "This study explores body size in sepiids (Cephalopoda, Sepiidae) on the interspecific scale and provides an overview of their geographical distribution. Results reveal a highly skewed distribution of body size variation for raw values and a nearly normal distribution for log-transformed data. However, normality is not statistically validated due to the overrepresentation of small and large species. The geographical distribution of sepiids reveals five main clusters: Atlantic, Cape Basin, Indian Ocean, Asia-Pacific, and Australian. On average, clusters display more or less the same mean body size pattern except the Cape Basin cluster, which is statistically different from the others (smaller interspecific mean body size). The reasons remain unclear but a phylogenetic effect is suspected as southwest African coastal waters concentrate species from the 'Hemisepius' complex which is made up of small species. Sepiids do not obey Bergmann's rule: species from high latitudes do not tend to be larger than species from low latitudes.", "keyphrases": ["body size", "cephalopoda", "sepiidae"]}
{"id": "paleo.013057", "title": "Extending the spectrum of DNA sequences retrieved from ancient bones and teeth.", "abstract": "The number of DNA fragments surviving in ancient bones and teeth is known to decrease with fragment length. Recent genetic analyses of Middle Pleistocene remains have shown that the recovery of extremely short fragments can prove critical for successful retrieval of sequence information from particularly degraded ancient biological material. Current sample preparation techniques, however, are not optimized to recover DNA sequences from fragments shorter than \u223c35 base pairs (bp). Here, we show that much shorter DNA fragments are present in ancient skeletal remains but lost during DNA extraction. We present a refined silica-based DNA extraction method that not only enables efficient recovery of molecules as short as 25 bp but also doubles the yield of sequences from longer fragments due to improved recovery of molecules with single-strand breaks. Furthermore, we present strategies for monitoring inefficiencies in library preparation that may result from co-extraction of inhibitory substances during DNA extraction. The combination of DNA extraction and library preparation techniques described here substantially increases the yield of DNA sequences from ancient remains and provides access to a yet unexploited source of highly degraded DNA fragments. Our work may thus open the door for genetic analyses on even older material.", "keyphrases": ["dna sequence", "ancient bone", "library preparation", "tooth"]}
{"id": "paleo.007668", "title": "The Upper Triassic to Middle Jurassic strata and floras of the Junggar Basin, Xinjiang, Northwest China", "abstract": "The Upper Triassic to Middle Jurassic strata are well exposed and basically continuous in the Junggar Basin of Xinjiang, Northwest China. The Upper Triassic strata include the Huangshanjie Formation (lacustrine facies mainly) and Haojiagou Formation (fluvial to fluvialswamp facies). The Lower Jurassic consists of the coalbearing Badaowan Formation (fluvial swamp facies) and Sangonghe Formation (lacustrine facies mainly). The Middle Jurassic is composed of the large coal-bearing Xishanyao Formation (fluvial-swamp facies mainly) and Toutunhe Formation (variegated lacustrine facies). The Late Triassic to early Middle Jurassic floras from the basin consist of four floristic assemblages, including the Danaeopsis-Nanzhangophyllum assemblage (Ass. I, Carnian-Norian) and Glossophyllum-Cycadocarpidium assemblage (Ass. II, Norian-Rhaetian), belonging to the Late Triassic \"Northern China Flora\" (Danaeopsis-Bernoullia Flora), and the Neocalamites-Marattiopsis assemblage (Ass. III, Early Jurassic) and Coniopteris-Raphaelia assemblage (Ass. IV, Middle Jurassic), belonging to the Early-Middle Jurassic \"Siberian Flora\" (Continental Floristic Province). The palaeoclimatic changes basically consisted of warming up and moistening from the Late Triassic to Early Jurassic, while the climate of the early Middle Jurassic might have been warm-temperate and humid, which was favourable for coal formation. The lower Middle Jurassic strata appear to be the largest sedimentary mineral resources for coal, oil and natural gas in the Junggar Basin area. Two new taxa from the Upper Jurassic are described, Danaeopsis tenuinervis Sun, Mosbrugger et Li sp. nov and Thinnfeldia? mirisecta Sun, Mosbrugger et Li sp. nov.", "keyphrases": ["middle jurassic strata", "flora", "junggar basin"]}
{"id": "10.1111/j.1475-4983.2006.00548.x", "title": "A NEW SPECIES OF MOERITHERIUM (PROBOSCIDEA, MAMMALIA) FROM THE EOCENE OF ALGERIA: NEW PERSPECTIVES ON THE ANCESTRAL MORPHOTYPE OF THE GENUS", "abstract": "Abstract:\u2002 A new species of Moeritherium (Proboscidea, Mammalia), M.\u2003chehbeurameuri sp. nov., is described from remains discovered in the early late Eocene locality of Bir El Ater, Algeria. Although mainly represented by isolated teeth, it shows distinct synapomorphies which justify its attribution to the genus Moeritherium, together with exclusive features that led to the creation of the new species. The main characteristic of this new taxon is the almost complete lophodonty shown by its molars, while Moeritherium is commonly regarded as a bunolophodont to bunodont taxon. In addition to this lophodonty, this new taxon shows anatomical features as yet unknown for the genus, but often met within lophodont early proboscidean taxa such as Phosphatherium escuilliei and Numidotherium koholense. Although a revision of the whole genus Moeritherium is outside the scope of this paper, the main controversies and discussion about the definition of species within the genus Moeritherium are discussed. The surprising lophodonty of M.\u2003chehbeurameuri, together with its small size, its early late Eocene age and the weak molarization of its P3 support the hypothesis of a lophodont hypothetical ancestor for moeritheres, and therefore strengthen the growing hypothesis of a lophodont dental ancestral morphotype for proboscideans.", "keyphrases": ["moeritherium", "mammalia", "ancestral morphotype"]}
{"id": "10.7717/peerj.2578", "title": "A revision of Sanpasaurus yaoi Young, 1944 from the Early Jurassic of China, and its relevance to the early evolution of Sauropoda (Dinosauria)", "abstract": "The Early Jurassic of China has long been recognized for its diverse array of sauropodomorph dinosaurs. However, the contribution of this record to our understanding of early sauropod evolution is complicated by a dearth of information on important transitional taxa. We present a revision of the poorly known taxon Sanpasaurus yaoi Young, 1944 from the late Early Jurassic Ziliujing Formation of Sichuan Province, southwest China. Initially described as the remains of an ornithopod ornithischian, we demonstrate that the material catalogued as IVPP V156 is unambiguously referable to Sauropoda. Although represented by multiple individuals of equivocal association, Sanpasaurus is nonetheless diagnosable with respect to an autapomorphic feature of the holotypic dorsal vertebral series. Additional material thought to be collected from the type locality is tentatively referred to Sanpasaurus. If correctly attributed, a second autapomorphy is present in a referred humerus. The presence of a dorsoventrally compressed pedal ungual in Sanpasaurus is of particular interest, with taxa possessing this typically \u2018vulcanodontid\u2019 character exhibiting a much broader geographic distribution than previously thought. Furthermore, the association of this trait with other features of Sanpasaurus that are broadly characteristic of basal eusauropods underscores the mosaic nature of the early sauropod\u2013eusauropod transition. Our revision of Sanpasaurus has palaeobiogeographic implications for Early Jurassic sauropods, with evidence that the group maintained a cosmopolitan Pangaean distribution.", "keyphrases": ["sanpasaurus yaoi young", "china", "sauropoda"]}
{"id": "paleo.009319", "title": "Preliminary Analysis of Osteocyte Lacunar Density in Long Bones of Tetrapods: All Measures Are Bigger in Sauropod Dinosaurs", "abstract": "Osteocytes harbour much potential for paleobiological studies. Synchrotron radiation and spectroscopic analyses are providing fascinating data on osteocyte density, size and orientation in fossil taxa. However, such studies may be costly and time consuming. Here we describe an uncomplicated and inexpensive method to measure osteocyte lacunar densities in bone thin sections. We report on cell lacunar densities in the long bones of various extant and extinct tetrapods, with a focus on sauropodomorph dinosaurs, and how lacunar densities can help us understand bone formation rates in the iconic sauropod dinosaurs. Ordinary least square and phylogenetic generalized least square regressions suggest that sauropodomorphs have lacunar densities higher than scaled up or comparably sized mammals. We also found normal mammalian-like osteocyte densities for the extinct bovid Myotragus, questioning its crocodilian-like physiology. When accounting for body mass effects and phylogeny, growth rates are a main factor determining the density of the lacunocanalicular network. However, functional aspects most likely play an important role as well. Observed differences in cell strategies between mammals and dinosaurs likely illustrate the convergent nature of fast growing bone tissues in these groups.", "keyphrases": ["osteocyte lacunar density", "long bone", "sauropod dinosaur", "growth rate"]}
{"id": "paleo.006316", "title": "A new genus of eomyid rodent from the Miocene of Nevada", "abstract": "The description of a new genus (Apeomyoides) of eomyid rodent from the Miocene of Nevada increases the diversity of known taxa, enhances the geographic range, and extends the biochronology for the Apeomyinae (Eomyidae). Three groups of Eomyidae are known from the fossil record of North America. Of the three groups, Neogene taxa include four genera representing the Eomyinae and two genera representing the Apeomyinae; no genera of the subfamily Yoderimyinae are known from the Neogene of the continent. This diversity represents a significant reduction of eomyid taxa compared to the Paleogene, from which 17 genera of eomyines and three genera of yoderimyines are known. In Eurasia, 11 genera of eomyids occurred during the Neogene, with a few taxa that persisted until about 2 million years before present. At present, there are no known eomyids from the last 4.5 million years of the Neogene in North America. Apeomyoides savagei is referable to the subfamily Apeomyinae based on several key structures of the teeth and mandible. This new eomyid is part of the Eastgate local fauna, collected from volcanic ash deposits of the Monarch Mill Formation, Churchill County, Nevada. Apeomyoides has an occlusal pattern that shares characteristics of apeomyines from both North America (Megapeomys and Arikareeomys) and Eurasia (Apeomys and Megapeomys). The unique occlusal pattern and large size of Apeomyoides demonstrates that not all eomyids from North America were small or that their lineages decreased in size through time. Apeomyoides also may provide evidence, which challenges the hypothesis that eomyids within a single lineage from North America became more lophodont in geologically younger genera.", "keyphrases": ["new genus", "eomyid rodent", "miocene"]}
{"id": "paleo.002788", "title": "A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system", "abstract": "A new species of tyrannosaurid from the upper Two Medicine Formation of Montana supports the presence of a Laramidian anagenetic (ancestor-descendant) lineage of Late Cretaceous tyrannosaurids. In concert with other anagenetic lineages of dinosaurs from the same time and place, this suggests that anagenesis could have been a widespread mechanism generating species diversity amongst dinosaurs, and perhaps beyond. We studied the excellent fossil record of the tyrannosaurid to test that hypothesis. Phylogenetic analysis places this new taxon as the sister species to Daspletosaurus torosus. However, given their close phylogenetic relationship, geographic proximity, and temporal succession, where D. torosus (~76.7\u201375.2 Ma) precedes the younger new species (~75.1\u201374.4 Ma), we argue that the two forms most likely represent a single anagenetic lineage. Daspletosaurus was an important apex predator in the late Campanian dinosaur faunas of Laramidia; its absence from later units indicates it was extinct before Tyrannosaurus rex dispersed into Laramidia from Asia. In addition to its evolutionary implications, the texture of the facial bones of the new taxon, and other derived tyrannosauroids, indicates a scaly integument with high tactile sensitivity. Most significantly, the lower jaw shows evidence for neurovasculature that is also seen in birds.", "keyphrases": ["anagenesis", "tyrannosaurid", "daspletosaurus", "scaly integument"]}
{"id": "10.1111/pala.12189", "title": "The oldest known bryozoan: Prophyllodictya (Cryptostomata) from the lower Tremadocian (Lower Ordovician) of Liujiachang, south\u2010western Hubei, central China", "abstract": "A new cryptostome bryozoan, Prophyllodictya simplex sp. nov., is described from the Nantzinkuan Formation (Lower Ordovician, lower Tremadoc) of Liujiachang, central China. This antedates the previously oldest known bryozoan by several million years. Colony morphology and the phylogenetic position of Prophyllodictya within Cryptostomata are explored. Phylogenetic analysis suggests that Cryptostomata (except Prophyllodictya) can be divided into two major groups, and that Prophyllodictya occupies a basal position in the cryptostome tree, which accords with its simple morphology and antiquity. A close relationship is evident between bryozoans from the South China palaeoplate and those from Baltica.", "keyphrases": ["bryozoan", "cryptostomata", "lower ordovician"]}
{"id": "10.1080/02724634.2015.1062022", "title": "The First Fossil Record of Borophagine Dogs (Mammalia, Carnivora) from South Carolina, U.S.A.", "abstract": "Citation for this article: Tseng, Z. J., and J. H. Geisler. 2016. The first fossil record of borophagine dogs (Mammalia, Carnivora) from South Carolina, U.S.A. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2015.1062022.", "keyphrases": ["first fossil record", "mammalia", "carnivora"]}
{"id": "paleo.001622", "title": "A NEW GENUS OF RHYNCHOSAUR FROM THE MIDDLE TRIASSIC OF SOUTH\u2010WEST ENGLAND", "abstract": "Abstract:\u2002 We present a description of new cranial and postcranial material representing a new genus of rhynchosaur (Diapsida, Archosauromorpha) from the Otter Sandstone Formation (Mid Triassic) of Devon, south\u2010west England. The taxon had been named Rhynchosaurus spenceri Benton, 1990 , but cladistic analysis of the clade, and one autapomorphy, show that it does not belong to Rhynchosaurus, and a new generic name is required. We propose the name Fodonyx for this genus. A cladistic analysis of the Rhynchosauria confirms the main discoveries of previous analyses, and that Fodonyx is sister group to the Hyperodapedontinae, the clade of Late Triassic rhynchosaurs. The new cladistic analysis, for which many more characters were coded for Fodonyx than before (a rise from 39 to 75 per cent), counter\u2010intuitively produced less well\u2010resolved results: the new codings of previously uncoded characters introduced conflict so that Fodonyx turns out to be less like the Late Triassic rhynchosaur clade than had been assumed before.", "keyphrases": ["new genus", "rhynchosaur", "south\u2010west england"]}
{"id": "10.1080/02724634.2019.1576701", "title": "Reappraisal of \u2018Metoposaurus hoffmani\u2019 Dutuit, 1978, and description of new temnospondyl specimens from the Middle\u2013Late Triassic of Madagascar (Morondava Basin)", "abstract": "ABSTRACT Temnospondyls from the Middle\u2013Late Triassic of Madagascar are problematic and scarce: \u2018Metoposaurus hoffmani\u2019 was erected on the basis of poor material, and this taxon has never been revised. Other remains were also reported and assigned to Temnospondyli indet., but they have never been described, nor figured. Here, we (re)describe in detail this historical material from the Folakara area of Madagascar (Isalo Group, Morondava Basin): the specimens include cranial and postcranial remains, most of them being referred to Metoposauridae indet. and a few to Stereospondyli indet. We also confirm that \u2018M. hoffmani\u2019 is a nomen dubium owing to the absence of any clear autapomorphy of the fragmentary type material. The material referred here to Metoposauridae indet. is incorporated in an updated paleobiogeographic analysis of the group: interestingly, it suggests a connection with Indian metoposaurids during the Late Triassic.", "keyphrases": ["metoposaurus hoffmani", "middle\u2013late triassic", "morondava basin"]}
{"id": "paleo.000053", "title": "Earth\u2019s oldest \u2018Bobbit worm\u2019 \u2013 gigantism in a Devonian eunicidan polychaete", "abstract": "Whilst the fossil record of polychaete worms extends to the early Cambrian, much data on this group derive from microfossils known as scolecodonts. These are sclerotized jaw elements, which generally range from 0.1\u20132 mm in size, and which, in contrast to the soft-body anatomy, have good preservation potential and a continuous fossil record. Here we describe a new eunicidan polychaete, Websteroprion armstrongi gen. et sp. nov., based primarily on monospecific bedding plane assemblages from the Lower-Middle Devonian Kwataboahegan Formation of Ontario, Canada. The specimens are preserved mainly as three-dimensional moulds in the calcareous host rock, with only parts of the original sclerotized jaw walls occasionally present. This new taxon has a unique morphology and is characterized by an unexpected combination of features seen in several different Palaeozoic polychaete families. Websteroprion armstrongi was a raptorial feeder and possessed the largest jaws recorded in polychaetes from the fossil record, with maxillae reaching over one centimetre in length. Total body length of the species is estimated to have reached over one metre, which is comparable to that of extant \u2018giant eunicid\u2019 species colloquially referred to as \u2018Bobbit worms\u2019. This demonstrates that polychaete gigantism was already a phenomenon in the Palaeozoic, some 400 million years ago.", "keyphrases": ["bobbit worm", "gigantism", "eunicidan polychaete", "jaw"]}
{"id": "paleo.005540", "title": "PARASITISM VERSUS COMMENSALISM: THE CASE OF TABULATE ENDOBIONTS", "abstract": "Abstract:\u2002 Tube\u2010like traces of organisms belonging to the ichnogenus Chaetosalpinx Sokolov have been considered in the literature as commensal endobiontic organisms of tabulate corals. Their position between the corallites (or sometimes within the septa), perforation of the host's skeleton and soft tissue, modification of its phenotype and a possible inhibition of its growth show that the relationship between these organisms and tabulate corals can best be interpreted as parasitism rather than commensalism, as previously suggested. Such an interpretation may be extended to the ichnogenera Helicosalpinx Oekentorp and Actinosalpinx Sokolov, which show identical placement within the host colony and similar features, such as the absence of their own wall.", "keyphrases": ["commensalism", "host", "parasitism", "symbiotic association"]}
{"id": "10.1130/G33881.1", "title": "How well do fossil assemblages of the Ediacara Biota tell time", "abstract": "Patterns of origination, evolution, and extinction of early animal life on this planet are largely interpreted from the fossils of the Precambrian soft-bodied Ediacara Biota, spanning nearly 40 m.y. of the terminal Ediacaran period. Localities containing these fossils are loosely considered as part of either the Avalon, White Sea, or Nama Associations. These associations have been interpreted to have temporal, paleobiogeographic, preservational, and/or paleoenvironmental significance. Surprisingly, elements of all three associations occur within the Ediacara Member of the Rawnsley Quartzite of South Australia. An analysis of over 5000 specimens demonstrates that fossil distribution is strongly controlled by facies and taphonomy rather than time or biogeography and that individual taxa vary considerably in their environmental tolerance and taphonomic integrity. The recognition that these taxa represent organisms living in various distinct environments, both juxtaposed and shared, holds strong implications for our interpretation of the record of early animal life on this planet and questions the biostratigraphic utility of the three associations. Furthermore, although in situ soft-bodied preservation provides a unique perspective on composition of benthic fossil assemblages, the record should not be interpreted as a simple \u201csnapshot\u201d. Fossil beds represent a range of preservational modifications varying from current winnowed census samples of benthic communities at different depths and ecological maturity, to entirely transported assemblages. Unless the appropriate environments and taphonomic conditions are present for certain taxa, the absence of a particular taxon may or may not indicate its extinction in space or time.", "keyphrases": ["fossil assemblage", "ediacara biota", "south australia"]}
{"id": "10.1029/2004PA001129", "title": "Long-period orbital control on middle Miocene global cooling: Integrated stratigraphy and astronomical tuning of the Blue Clay Formation on Malta", "abstract": "[1]\u00a0Application of an astronomical age model to a bulk carbonate oxygen isotope record in the Ras il Pellegrin section on Malta indicates that the major step in the middle Miocene global cooling (13.82 Ma \u00b1 0.03) coincides with minimum eccentricity values associated with the 400-kyr cycle and minimum obliquity amplitudes associated with the 1.2-Myr cycle. This orbital configuration is very similar to that found for comparable oxygen isotope enrichment events in the late Paleogene and Neogene. The stepwise character of the middle Miocene cooling event appears to be controlled by the combined influence of the 100-kyr eccentricity cycle and the 172-kyr cycle in obliquity amplitude. The integrated stratigraphy further allows extension of the astronomical polarity timescale to the top of chron C5ACn. The boundary between the Globigerina Limestone and the Blue Clay Formation coincides with the major step in middle Miocene global cooling and provides a level suitable for placing the physical reference point for the Langhian/Serravallian boundary.", "keyphrases": ["middle miocene", "global cooling", "stratigraphy"]}
{"id": "10.1111/j.1475-4983.2011.01104.x", "title": "Dorlodotia and related genera (Rugosa) from the Visean (Mississippian; Carboniferous) of Zonguldak and Bartin (North\u2010Western Turkey)", "abstract": "Abstract:\u2002 A rich and diverse coral fauna collected from the Livian (Vis\u00e9an, Mississippian) of Zonguldak and Bart\u0131n (North\u2010western Turkey) contains numerous specimens of Dorlodotia and related forms. The most common species, D. delepinei Charles, 1933 , is redetermined as Dorlodotia briarti, an European species. A new species of Dorlodotia is described for very large, phaceloid forms: D. euxinensis. The genus Ceriodotia is created for species close to Dorlodotia with a cerioid habit. It comprises two species: C. bartinensis and C. petalaxoides, both common in the Vis\u00e9an of Zonguldak and Bart\u0131n. Based on comparison of morphological characters and features of the astogeny, a phylogenetic lineage is proposed for Dorlodotia and the new taxa. The evolution of D. euxinensis from D. briarti is peramorphic. Subsequent paedomorphosis resulted in the lineage D. euxinensis\u2013C. bartinensis\u2013C. petalaxoides. Ceriodotia probably includes Vis\u00e9an taxa from Asia previously described as \u2018Acrocyathus\u2019.", "keyphrases": ["zonguldak", "north\u2010western turkey", "dorlodotia"]}
{"id": "paleo.008814", "title": "Earliest known unequivocal rhinocerotoid sheds new light on the origin of Giant Rhinos and phylogeny of early rhinocerotoids", "abstract": "Forstercooperiines are a group of primitive rhinocerotoids with a relatively large body size in the Eocene, and normally considered to be closely related to Giant Rhinos. Here we report a new forstercooperiine, Pappaceras meiomenus sp. nov., from the late Early Eocene Arshanto Formation, Erlian Basin, Nei Mongol, China. Pappaceras is the earliest known unequivocal rhinocerotoid, and the holotype of the new species, represented by the most complete cranium of forstercooperiines known to date, shows the earliest evidence of reduction of the first upper premolar in rhinocerotoids, and resembles paraceratheriine Juxia in basicranial features, supporting the interpretation that the forstercooperiine clade is ancestral to paraceratheriines. The new species also displays some similarities with amynodontids in craniodental structures. Phylogenetic analysis identifies P. meiomenus as a basal taxon of the monophyletic forstercooperiines. It also reveals\nnovel phylogenetic relationships of early rhinocerotoids that indicates Uintaceras is the sister group of paraceratheriids, to which amynodontids are more closely related than to any other group of rhinocerotoids. Furthermore, the eggysodontid clade is excluded from hyracodontids and placed as the sister group of rhinocerotids. Hyracodontidae, excluding paraceratheriids and eggysodontids, is placed as the most basal group of the rhinocerotoids.", "keyphrases": ["rhinocerotoid", "forstercooperiine", "pappaceras", "holotype", "asia"]}
{"id": "10.1111/joa.13389", "title": "Low elbow mobility indicates unique forelimb posture and function in a giant extinct marsupial", "abstract": "Joint mobility is a key factor in determining the functional capacity of tetrapod limbs, and is important in palaeobiological reconstructions of extinct animals. Recent advances have been made in quantifying osteological joint mobility using virtual computational methods; however, these approaches generally focus on the proximal limb joints and have seldom been applied to fossil mammals. Palorchestes azael is an enigmatic, extinct ~1000 kg marsupial with no close living relatives, whose functional ecology within Australian Pleistocene environments is poorly understood. Most intriguing is its flattened elbow morphology, which has long been assumed to indicate very low mobility at this important joint. Here, we tested elbow mobility via virtual range of motion (ROM) mapping and helical axis analysis, to quantitatively explore the limits of Palorchestes' elbow movement and compare this with their living and extinct relatives, as well as extant mammals that may represent functional analogues. We find that Palorchestes had the lowest elbow mobility among mammals sampled, even when afforded joint translations in addition to rotational degrees of freedom. This indicates that Palorchestes was limited to crouched forelimb postures, something highly unusual for mammals of this size. Coupled flexion and abduction created a skewed primary axis of movement at the elbow, suggesting an abducted forelimb posture and humeral rotation gait that is not found among marsupials and unlike that seen in any large mammals alive today. This work introduces new quantitative methods and demonstrates the utility of comparative ROM mapping approaches, highlighting that Palorchestes' forelimb function was unlike its contemporaneous relatives and appears to lack clear functional analogues among living mammals.", "keyphrases": ["forelimb posture", "marsupial", "freedom", "low elbow mobility"]}
{"id": "10.26879/804", "title": "Mammals from the earliest Uintan (middle Eocene) Turtle Bluff Member, Bridger Formation, southwestern Wyoming, USA, Part 3: Marsupialia and a reevaluation of the Bridgerian-Uintan North American Land Mammal Age transition", "abstract": "This is the third and last of a series of reports that provide detailed descriptions and taxonomic revisions of the fauna from the Turtle Bluff Member (TBM) of the middle Eocene Bridger Formation of southwestern Wyoming. The TBM has been designated as the stratotype section for biochron Ui1a (earliest Uintan) of the Uintan North American Land Mammal age and here we document new faunal elements along with new UPb geochronologic and paleomagnetic data for the TBM. Prior to these reports, detailed systematic accounts of the taxa from the TBM were unavailable with the exception of one primate (Hemiacodon engardae). Here we document the occurrence of the following didelphimorphian marsupials from the TBM: Herpetotherium knighti, Herpetotherium marsupium, Peradectes chesteri, and Peradectes californicus. New UPb dates of 47.31 \u00b1 0.06 Ma and 46.94 \u00b1 0.14 Ma from the TBM provide precise constraints on the age of the fauna. These dates plus new paleomagnetic data further support the existing evidence that the TBM Fauna and the boundary between the Bridgerian and Uintan North American Land Mammal ages occurs within the lower part of Chron C21n of the Geomagnetic Polarity Time Scale. The only other fauna from North America that can confidently be assigned to biochron Ui1a is the Basal Tertiary Local Fauna from the Devil's Graveyard Formation of Texas. Revisions of the faunal characterizations of biochrons Ui1a (earliest Uintan) and Ui1b (early Uintan) of the Uintan North America Land Mammal age are proposed to further clarify their differences. Paul C. Murphey. Research Associate, Department of Paleontology, San Diego Museum of Natural History, 1788 El Prado, San Diego, California 92101, USA. pmurphey@sdnhm.org Thomas S. Kelly. Research Associate, Vertebrate Paleontology Department, Natural History Museum of Los Angeles County, 900 Exposition Blvd., Los Angeles, California 90007, USA. tom@tskelly.gardnerville.nv.us Kevin R. Chamberlain. Research Professor, Department of Geology and Geophysics, University of Wyoming, 1000 E. University Ave., Laramie, Wyoming 82071, USA and Faculty of Geology and Murphey, Paul C., Kelly, Thomas S., Chamberlain, Kevin R., Tsukui, Kaori, and Clyde, William C. 2018. Mammals from the earliest Uintan (middle Eocene) Turtle Bluff Member, Bridger Formation, southwestern Wyoming, USA, Part 3: Marsupialia and a reevaluation of the Bridgerian-Uintan North American Land Mammal Age transition. Palaeontologia Electronica 21.2.25A 1-52. https://doi.org/", "keyphrases": ["middle eocene", "southwestern wyoming", "marsupialia"]}
{"id": "10.1371/journal.pone.0258974", "title": "New insights into the Upper Palaeolithic of the Caucasus through the study of personal ornaments. Teeth and bones pendants from Satsurblia and Dzudzuana caves (Imereti, Georgia)", "abstract": "The region of western Georgia (Imereti) in the Southern Caucasus has been a major geographic corridor for human migrations during the Middle and Upper Paleolithic. Data of recent research and excavations in this region display its importance as a possible route for the dispersal of anatomically modern humans (AMH) into northern Eurasia. Nevertheless, within the local research context, bone-working and personal ornaments have yet contributed but little to the Upper Palaeolithic (UP) regional sequence\u2019s characterization. Here we present an archaeozoological, technological and use-wear study of pendants from two local UP assemblages, originating in the Dzudzuana Cave and Satsurblia Cave. The ornaments were made mostly of perforated teeth, though some specimens were made on bone. Both the manufacturing marks made during preparation and use-wear traces indicate that they were personal ornaments, used as pendants or attached to garments. Detailed comparison between ornament assemblages from northern and southern Caucasus reveal that they are quite similar, supporting the observation of cultural bonds between the two regions, demonstrated previously through lithic techno-typological affinities. Furthermore, our study highlights the importance attributed to red deer (Cervus elaphus) by the UP societies of the Caucasus in sharing aesthetic values and/or a symbolic sphere.", "keyphrases": ["upper palaeolithic", "dzudzuana cave", "tooth"]}
{"id": "10.1130/GES00176.1", "title": "Quantifying foraminiferal growth with high-resolution X-ray computed tomography: New opportunities in foraminiferal ontogeny, phylogeny, and paleoceanographic applications", "abstract": "The latest generation of high-resolution X-ray computed tomography (HRXCT), with a submicron resolution, enables for the first time three-dimensional (3D) imaging and bio-metric quantification of foraminiferal interiors. Here we exemplify the basic possibilities and opportunities of this new technique by means of an analysis on a fossil specimen of Pseudouvigerina sp. from the basal Paleocene of the Brazos River, Texas. The total scan consists of 1200 X-ray radiographs generated during stepwise rotation (0.3 degrees) of the specimen. These radiographs were processed and reconstructed to build cross-sectional images of the object. After 3D rendering of the data, the specimens' chambers could be segmented, showing an exponential ontogenetic growth rate. From the second chamber onward (i.e., after the megalospheric proloculus with a volume of 10(4) mu m(3)), the size of the chambers steadily increases by a factor of similar to 1.5. Various other dimensions can also be calculated from the scan, such as the total volume of shell calcite or the size of the foramen. The technological improvements with HRXCT could open up a new era in fundamental biometric-evolutionary research and provide a means of morphologic evaluation of phylogenies based on molecular data. Eventually, the accuracy of paleoceanographic and paleoclimatic reconstructions could also benefit from the possibility of morphological differentiation between cryptic planktic species.", "keyphrases": ["high-resolution x-ray", "tomography", "opportunity"]}
{"id": "10.1080/03115518.2015.994115", "title": "Revision of Wabularoo, an early macropodid kangaroo from mid-Cenozoic deposits of the Riversleigh World Heritage Area, Queensland, Australia", "abstract": "Travouillon, K.J., Archer, M. & Hand, S.J., 21.01.2015. Revision of Wabularoo, an early macropodid kangaroo from mid-Cenozoic deposits of the Riversleigh World Heritage Area, Queensland, Australia. Alcheringa 39, xxx\u2013xxx. ISSN 0311-5518 Since its original description, the phylogenetic relationships of the macropodoid Wabularoo naughtoni Archer, 1979, from the Riversleigh World Heritage Area have remained a mystery. We have recovered new material representing the upper dentition previously unknown for this late Oligocene taxon, and new early Miocene specimens representing the upper and lower dentition of a second species, W. prideauxi sp. nov. We assessed their phylogenetic relationships using matrices from two previous studies, and recovered both species of Wabularoo as basal macropodids. Wabularoo is characterized by having bilophodont molars, large sectorial P3/p3 with coarse ridges, presence of a forelink, neometaconule and postlink on M1\u20133, well-developed anterior cingulum, precingulum, postparacrista and premetacrista on all upper molars, and retention of StC on M1\u20132. Although the subfamilial affinities of Wabularoo are unresolved, we propose that several morphological features of the dentary and the upper and lower third premolar suggest affinity with Sthenurinae. These features include short diastema, posteriorly positioned digastric eminence, presence of posterior mental foramen, and similar molar and premolar morphology. If our interpretations are correct, sthenurines arose from basal macropodids between the early and middle Miocene. Kenny J. Travouillon [kennytravouillon@hotmail.com] School of Earth Sciences, University of Queensland, St Lucia, Queensland 4072, Australia; Michael Archer [m.archer@unsw.edu.au] and Suzanne J. Hand [s.hand@unsw.edu.au] School of Biological, Earth and Environmental Sciences, University of New South Wales, New South Wales 2052, Australia.", "keyphrases": ["wabularoo", "kangaroo", "mid-cenozoic deposit"]}
{"id": "10.5479/si.00810266.25.1", "title": "Revised tertiary stratigraphy and paleontology of the Western Beaver Divide, Fremont County, Wyoming", "abstract": "Emry, Robert J. Revised Tertiary Stratigraphy and Paleontology of the Western Beaver Divide, Fremont County, Wyoming. Smithsonian Contributions to Paleobiology, number 25, 20 pages, 6 figures, 1975.\u2022In the western Beaver Divide area in west-central Wyoming, a lens of coarse Tertiary volcanic conglomerate and tuff disconfqrmably overlies Uintan rocks of the Wagon Bed Formation. The coarse volcaniclastic rocks were previously regarded as a faci\u00e8s of the Beaver Divide Conglomerate Member of the Chadronian White River Formation, although fossil mammals from the volcaniclastic unit are species known otherwise only from Uintan rocks. Reexamination of field relations has shown that the White River Formation disconformably overlies the volcaniclastic unit. The \"lower Uinta C\" temporal equivalence indicated by the fossils from the volcaniclastic unit is no longer anomalous; the underlying Wagon Bed Formation has fossil mammals indicating \"Uinta B\" equivalence, and the overlying White River Formation has a fairly diverse Chadronian fauna. The Uintan volcaniclastic unit is assigned to the Wiggins Formation. The Beaver Divide Conglomerate Member is restricted to conglomerate in the lower part of the White River Formation. It is composed predominantly of clasts of locally derived Precambrian crystalline rocks. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institutions annual report, Smithsonian Year. SI PRESS NUMBER 6013. SERIES COVER DESICN: The trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Emry, Robert J. Revised tertiary stratigraphy and paleontology of the Western Beaver Divide, Fremont County, Wyoming. (Smithsonian contributions to paleobiology, no. 25) 1. Geology, Stragraphic\u2022Tertiary. 2. Paleontology\u2022Wyoming\u2022Fremont Co. 3. Paleontology\u2022 Tertiary. I. Title: Revised tertiary stratigraphy and paleontology of the Western Beaver Divide ... II. Series: Smithsonian Institution. Smithsonian contributions to paleobiology, no. 25. QE701.S56 no. 25 [QE691] 560'.8s [551.7'8'0978763] 75-8799", "keyphrases": ["tertiary stratigraphy", "paleontology", "western beaver divide", "white river formation"]}
{"id": "10.11646/palaeoentomology.2.3.13", "title": "A new dustywing (Neuroptera: Coniopterygidae) from the Early Cretaceous amber of Spain", "abstract": "A new Cretaceous dustywing, Soplaoconis ortegablancoi gen. et sp. nov. (Neuroptera: Coniopterygidae), is described from four specimens preserved in Early Cretaceous (Albian, ~105Ma) El Soplao amber (Cantabria, northern Spain). Two additional specimens are assigned to this new taxon. A crossvenational abnormality on an area of diagnostic significance from one of the holotype\u2019s forewings provides a reminder of the importance of not ruling out character plasticity or teratoses when evaluating palaeodiversity. A comment on the possible palaeoecological significance of the co-occurrence as syninclusions of plant trichomes with the holotype of S. ortegablancoi and seven of the eleven described Burmese amber dustywing species is provided.", "keyphrases": ["dustywing", "neuroptera", "coniopterygidae"]}
{"id": "paleo.005591", "title": "Three-dimensional geometric morphometric analysis of the skull of Protoceratops andrewsi supports a socio-sexual signalling role for the ceratopsian frill", "abstract": "Socio-sexual selection is predicted to be an important driver of evolution, influencing speciation, extinction and adaptation. The fossil record provides a means of testing these predictions, but detecting its signature from morphological data alone is difficult. There are, nonetheless, some specific patterns of growth and variation which are expected of traits under socio-sexual selection. The distinctive parietal-squamosal frill of ceratopsian dinosaurs has previously been suggested as a socio-sexual display trait, but evidence for this has been limited. Here, we perform a whole-skull shape analysis of an unprecedentedly large sample of specimens of Protoceratops andrewsi using a high-density landmark-based geometric morphometric approach to test four predictions regarding a potential socio-sexual signalling role for the frill. Three predictions\u2014low integration with the rest of the skull, significantly higher rate of change in size and shape during ontogeny, and higher morphological variance than other skull regions\u2014are supported. One prediction, sexual dimorphism in shape, is not supported, suggesting that sexual differences in P. andrewsi are likely to be small. Together, these findings are consistent with mutual mate choice or selection for signalling quality in more general social interactions, and support the hypothesis that the frill functioned as a socio-sexual signal in ceratopsian dinosaurs.", "keyphrases": ["skull", "socio-sexual signalling role", "frill"]}
{"id": "paleo.005159", "title": "Trilobite \u2018pelotons\u2019: possible hydrodynamic drag effects between leading and following trilobites in trilobite queues", "abstract": "Energy saving mechanisms in nature allow following organisms to expend less energy than leaders. Queues, or ordered rows of individuals, may form when organisms exploit the available energy saving mechanism while travelling at near\u2010maximal sustainable metabolic capacities; compact clusters form when group members travel well below maximal sustainable metabolic capacities. The group size range, given here as the ratio of the difference between the size of the largest and smallest group members, and the size of the largest member (as a percentage), has been hypothesized to correspond proportionately to the energy saving quantity because weaker, smaller, individuals sustain the speeds of stronger, larger, individuals by exploiting the energy saving mechanism (as a percentage). During migration, small individuals outside this range may perish, or form sub\u2010groups, or simply not participate in migratory behaviour. We approximate drag forces for leading and following individuals in queues of the late Devonian (c. 370 Ma) trilobite Trimerocephalus chopini. Applying data from literature on Rectisura herculea, a living crustacean, we approximate the hypothetical walking speed and maximal sustainable speeds for T. chopini. Our findings reasonably support the hypothesis that among the population of fossilized queues of T. chopini reported in the literature, trilobite size range was 75%, while the size range within queues was 63%; this corresponds reasonably with drag reductions in following positions that permit c. 61.5% energy saving for trilobites following others in optimal low\u2010drag positions. We model collective trilobite behaviour associated with hydrodynamic drafting.", "keyphrases": ["hydrodynamic drag effect", "queue", "trilobite"]}
{"id": "paleo.004848", "title": "Stereom microstructure of columnal latera: a character for assessing phylogenetic relationships in articulate crinoids", "abstract": "The stereom microstructure of columnal latera in various articulate crinoids is examined to ascertain its potential application in phylogenetic studies. Most show either a poorly ordered labyrinthic stereom or a more regularly ordered perforate stereom with lumina arranged in an en echelon pattern. Labyrinthic stereom is taxonomically widespread and is interpreted here as the plesiomorphic state. Perforate stereom, typically with an en echelon arrangement of elliptical lumina, appears confined to the Isocrinina and is considered to be apomorphic for that group. The absence of any development of perforate stereom in the bourgueticrinid Democrinus suggests that the bourgueticrinids have affinities with the comatulids rather than with the isocrinids. A second type of perforate stereom, with sinuous or straight lines of circular to elongate lumina, has been found only in Pentacrinites and may be autapomorphic for that group. The shape and spacing of stereom lumina on the columnal latera of different genera of isocrinids displays minor variation that may have some value for assessing phylogenetic affinity at genus and family level in taxa known only from columnals.", "keyphrases": ["columnal latera", "crinoid", "stereom microstructure"]}
{"id": "10.1002/2015PA002825", "title": "Carbon and oxygen isotopes of bulk carbonate in sediment deposited beneath the eastern equatorial Pacific over the last 8 million years", "abstract": "To improve the understanding and utility of bulk carbonate stable carbon and oxygen isotope measurements, we examine sediment from cores in the eastern equatorial Pacific that span the last 8Ma. We measured C-13 and O-18 in 791 samples from Integrated Ocean Drilling Program Site U1338 and Deep Sea Drilling Project Site 573, both located close to the Pacific equator. In 100 samples, we measured C-13 and O-18 on isolated <63 mu m and <38 mu m fractions, which concentrates calcareous nannofossil carbonate and progressively excludes foraminiferal carbonate. Bulk carbonate C-13 and O-18 records are similar to published records from other sites drilled near the equator and seem to reflect mixed layer conditions, albeit with some important caveats involving the precipitation of calcite by coccolithophores. The comparatively lower C-13 and O-18 of the <63 mu m and <38 mu m fractions in sediments younger than 4.4Ma is attributed to an increase in deep-dwelling planktic foraminifera material in bulk carbonate, shifting the bulk isotopic signals toward higher values. Bulk carbonate C-13 is similar over 2500km along the Pacific equator, suggesting covarying concentrations and C-13 of dissolved inorganic carbon within surface waters since 8Ma. Greater bulk sediment C-13 and O-18, higher sedimentation rates, and low content of coarse material suggest intensified wind-driven upwelling and enhanced primary productivity along the Pacific equator between 8.0 and 4.4Ma, although a full understanding of bulk carbonate records will require extensive future work.", "keyphrases": ["bulk carbonate", "eastern equatorial pacific", "carbon"]}
{"id": "10.1111/ecog.03074", "title": "Bumblebees take the high road: climatically integrative biogeography shows that escape from Tibet, not Tibetan uplift, is associated with divergences of present\u2010day Mendacibombus", "abstract": "Many claims that uplift of the Qinghai-Tibetan plateau (QTP) drove the divergences of extant high-elevation biota have recently been challenged. For Mendacibombus bumblebees, high-elevation specialists with distributions centred on the QTP, we examine broader explanations. We extend integrative biogeography to cover multiple contributing factors by using a framework of sequential filters: 1) molecular evidence from four genes is used to estimate phylogenetic relationships, with time calibration from a published estimate; 2) spatial evidence from current distributions is combined with the phylogeny and constrained by a model of short-distance dispersal along mountain corridors to estimate ancestral distributions by both S-DIVA and S-DEC analysis; 3) geological evidence from the literature is used to constrain when high mountain ranges were uplifted to become potential corridors; and 4) climatological evidence from Mendacibombus niche-evolution reconstructions and from palaeoclimate simulations is used to constrain when habitat was suitable in key gaps within corridors. Explanations for Mendacibombus distributions can be identified that require only short-distance dispersal along mountain corridors, commensurate with the limited dispersal ability observed for bumblebees. These explanations depend on the timing of uplift of mountain ranges, regional climate change, and climate-niche evolution. The uplift of the QTP may have contributed to the initial Oligocene divergence of the common ancestor of Mendacibombus from other bumblebees, but for the first two thirds of the history of Mendacibombus, only a single lineage has present-day descendants. Divergence of multiple extant Mendacibombus lineages coincided with the Late Miocene\u2013Pliocene uplift of externally connecting mountains, combined with regional climate cooling. These changes provided greater connectivity of suitable habitat, allowing these bumblebees to disperse out of the western QTP via new high bridges, escaping along the mountain corridors of the Tian Shan and Hindu Kush ranges, reaching eventually far to the west (Iberian Peninsula) and to the north-east (Kamchatka).", "keyphrases": ["biogeography", "uplift", "dispersal", "bumblebee"]}
{"id": "10.1371/journal.pone.0172409", "title": "A new genus and species of marine catfishes (Siluriformes; Ariidae) from the upper Eocene Birket Qarun Formation, Wadi El-Hitan, Egypt", "abstract": "Wadi El-Hitan, the UNESCO World Heritage Site, of the Fayum Depression in the northeast part of the Western Desert of Egypt, has produced a remarkable collection of Eocene vertebrates, in particular the fossil whales from which it derives its name. Here we describe a new genus and species of marine catfishes (Siluriformes; Ariidae), Qarmoutus hitanensis, from the base of the upper Eocene Birket Qarun Formation, based on a partial neurocranium including the complete left side, partial right dentary, left suspensorium, two opercles, left pectoral girdle and spine, nuchal plates, first and second dorsal spines, Weberian apparatus and a disassociated series of abdominal vertebrae. All of the elements belong to the same individual and some of them were found articulated. Qarmoutus gen. nov. is the oldest and the most complete of the Paleogene marine catfishes unearthed from the Birket Qarun Formation. The new genus exhibits distinctive features not seen in other African Paleogene taxa, such as different sculpturing on the opercle and pectoral girdle with respect to that on the neurocranium and nuchal plates, denticulate ornamentation on the skull bones arranged in longitudinal rows and forming a radiating pattern on the sphenotic, pterotic, extrascapular and the parieto-supraoccipital, indentations or pitted ornamentation on the nuchal plates as well as the parieto-supraoccipital process, strut-like radiating pattern of ornamentation on the opercle from the proximal articulation to margins, longitudinal, curved, reticulate ridges and tubercular ornamentations on the cleithrum, sinuous articulation between the parieto-supraoccipital process and the anterior nuchal plate, long, narrow, and arrowhead shaped nuchal shield, very small otic capsules restricted to the prootic. Multiple parsimony and Bayesian morphological phylogenetic analyses of Ariidae, run with and without \u201cmolecular scaffolds\u201d, yield contradictory results for the placement of Qarmoutus; the genus is either a phylogenetically basal ariid, or it is deeply nested within the ariid clade containing New World species of Sciades.", "keyphrases": ["new genus", "marine catfish", "ariidae"]}
{"id": "10.1111/j.1096-3642.2005.00181.x", "title": "A review of the lower actinopterygian phylogeny", "abstract": "A review of lower actinopterygian phylogeny has led us to the conclusion that the Cladistia are the sister group of Recent actinopterygians (Actinopteri) and that the extinct Palaeonisciformes are a paraphyletic group, comprising stem-group actinopterygians (e.g. Cheirolepis), stem-group actinopterans (e.g. Moythomasia) and relatives of higher actinopterans such as Pteronisculus. Our analysis further concluded that the Acipenseriformes formed a clade together with Saurichthys and Birgeria, which was most parsimoniously resolved when the Acipenseriformes and Saurichthys were sister groups. (C) 2005 The Linnean Society of London.", "keyphrases": ["review", "low actinopterygian phylogeny", "paleozoic"]}
{"id": "10.1080/14772019.2012.708674", "title": "New evidence from the Palaeocene of Patagonia (Argentina) on the evolution and palaeo-biogeography of Meiolaniformes (Testudinata, new taxon name)", "abstract": "Peligrochelys walshae gen. et sp. nov. is a new stem turtle closely related to the clade Meiolaniidae found in the Palaeocene levels of the Salamanca Formation (Maastrichtian\u2013Danian) of central Patagonia, Chubut Province, Argentina. A phylogenetic analysis shows that Peligrochelys walshae forms a monophyletic group with Mongolochelys efremovi, a clade that, in return, is the sister group of a clade formed by Patagoniaemys gasparinae, Otwayemys cunicularius, Kallokibotion bajazidi and Meiolaniidae. Meiolaniidae is recovered deeply nested in a monophyletic group (Meiolaniformes, new taxon name) dominated by Gondwanan taxa (e.g. Chubutemys copelloi, Patagoniaemys gasparinae, Otwayemys cunicularius and Peligrochelys walshae), that also includes some notable Laurasian representatives (Mongolochelys efremovi and Kallokibotion bajazidi). The biogeographic scenario presented here supports the hypothesis that this group of turtles may have originated as early as the Early Cretaceous in the South American part of Gondwana. The long ghost lineage that extends below this clade suggests that it may have originated any time between the Early Jurassic and the Early Cretaceous, implying a Pangaean or Gondwanan origin for the clade, respectively. The phylogenetic scenario presented here shows that at least two lineages (Peligrochelys walshae and Meiolaniidae) of Meiolaniformes survived the K\u2013P boundary extinction. Another interesting characteristic of meiolaniform turtles in the fossil record is their frequent association with another clade of strictly Gondwanan distribution, the pleurodiran clade Chelidae. This association is typically found in outcrops from the Early Cretaceous to the Eocene in central Patagonia, and in the Early Cretaceous and from the Miocene to the Pleistocene in Australia.", "keyphrases": ["patagonia", "meiolaniformes", "new taxon name"]}
{"id": "10.1017/pab.2016.27", "title": "Tooth occlusal morphology in the durophagous marine reptiles, Placodontia (Reptilia: Sauropterygia)", "abstract": "Abstract. \n Placodontia were a group of marine reptiles that lived in shallow nearshore environments during the Triassic. Based on tooth morphology it has been inferred that they were durophagous, but tooth morphology differs among species: placodontoid placodonts have teeth described as hemispherical, and the teeth of more highly nested taxa within the cyamodontoid placodonts have been described as flat. In contrast, the sister taxon to the placodonts, Palatodonta bleekeri, like many other marine reptiles, has tall pointed teeth for eating soft-bodied prey. The goals of this paper are to quantify these different tooth morphologies and compare tooth shape among taxa and with a functionally \u201coptimal\u201d tooth. To quantify tooth morphology we measured the radius of curvature (RoC) of the occlusal surface by fitting spheres to 3D surface scans or computed microtomographic scans. Large RoCs correspond to flatter teeth, while teeth with smaller RoCs are pointier; positive RoCs have convex occlusal surfaces, and a negative RoC indicates that the occlusal surface of the tooth is concave. We found the placodontoid taxa have teeth with smaller RoCs than more highly nested taxa, and palatine teeth tend to be flatter and closer to the optimal morphology than maxillary teeth. Within one well-nested clade, the placochelyids, the rearmost palatine teeth have a more complex morphology than the predicted optimal tooth, with an overall concave occlusal surface with a small, medial cusp. These findings are in keeping with the hypothesis that placodonts were specialized durophagous predators with teeth modified to break hard prey items while resisting tooth failure.", "keyphrases": ["marine reptile", "placodontia", "tooth"]}
{"id": "10.1002/ajpa.22003", "title": "New craniodental material of Pronothodectes gaoi Fox (Mammalia, \"Plesiadapiformes\") and relationships among members of Plesiadapidae.", "abstract": "Plesiadapidae are a family of Paleogene mammals thought to have phylogenetic affinities with modern Primates. We describe previously unpublished dentitions and the first skull and isolated petrosals of the plesiadapid Pronothodectes gaoi, collected from middle Tiffanian localities of the Paskapoo Formation in Alberta. Other species of Pronothodectes, traditionally considered the most basal members of the Plesiadapidae, occur at earlier, Torrejonian horizons in Montana, Wyoming, and Alberta. Classification of P. gaoi as a species of Pronothodectes has proved controversial; accordingly, we use the newly available samples and the more extensively preserved specimens to re-evaluate the generic affinities of this species. Included in our study are comparisons with craniodental material known for other plesiadapids and plesiadapiforms. Cladistic analysis of craniodental characters is used to assess the hypothesis that P. gaoi and other species in this genus are basal members of the Plesiadapidae. The new dental evidence confirms that P. gaoi lacks derived character states of other plesiadapids except for a variably present fissuring of the m3 hypoconulid. Moreover, several aspects of the cranium seem to be more primitive in P. gaoi (i.e., more like nonplesiadapid plesiadapiforms) than in later occurring plesiadapids, such as Plesiadapis tricuspidens and Plesiadapis cookei. Cladistic analysis of craniodental morphology supports a basal position of P. gaoi among species of Plesiadapidae, with the exception of other species of Pronothodectes. The basicranium of P. gaoi preserves a laterally placed bony canal for the internal carotid neurovascular system, suggesting that this was the ancestral condition for the family.", "keyphrases": ["craniodental material", "pronothodectes", "plesiadapidae"]}
{"id": "10.5194/cp-12-483-2016", "title": "Climate variability and human impact in South America during the last 2000 years: synthesis and perspectives from pollen records", "abstract": "An improved understanding of present-day climate variability and change relies on high-quality data sets from the past 2 millennia. Global efforts to model regional climate modes are in the process of being validated against, and integrated with, records of past vegetation change. For South America, however, the full potential of vegetation records for evaluating and improving climate models has hitherto not been sufficiently acknowledged due to an absence of information on the spatial and temporal coverage of study sites. This paper therefore serves as a guide to high-quality pollen records that capture environmental variability during the last 2 millennia. We identify 60 vegetation (pollen) records from across South America which satisfy geochronological requirements set out for climate modelling, and we discuss their sensitivity to the spatial signature of climate modes throughout the continent. Diverse patterns of vegetation response to climate change are observed, with more similar patterns of change in the lowlands and varying intensity and direction of responses in the highlands. Pollen records display local-scale responses to climate modes; thus, it is necessary to understand how vegetation\u2013climate interactions might diverge under variable settings. We provide a qualitative translation from pollen metrics to climate variables. Additionally, pollen is an excellent indicator of human impact through time. We discuss evidence for human land use in pollen records and provide an overview considered useful for archaeological hypothesis testing and important in distinguishing natural from anthropogenically driven vegetation change. We stress the need for the palynological community to be more familiar with climate variability patterns to correctly attribute the potential causes of observed vegetation dynamics. This manuscript forms part of the wider LOng-Term multi-proxy climate REconstructions and Dynamics in South America \u2013 2k initiative that provides the ideal framework for the integration of the various palaeoclimatic subdisciplines and palaeo-science, thereby jump-starting and fostering multidisciplinary research into environmental change on centennial and millennial timescales.", "keyphrases": ["south america", "pollen record", "indicator", "climate variability"]}
{"id": "10.1080/02724634.1996.10011331", "title": "?Brachychampsa sealeyi, sp nov., (Crocodylia, Alligatoroidea) from the Upper Cretaceous (lower Campanian) Menefee Formation, northwestern New Mexico", "abstract": "ABSTRACT ?Brachychampsa sealeyi sp. nov. is a small alligatoroid based on a partial skull, associated partial mandible, and a dorsal? osteoderm from the Upper Cretaceous (lower Campanian) Menefee Formation, northwestern New Mexico. The holotype of ?B. sealeyi is the oldest of four documented Late Cretaceous alligatoroid skulls. ?Brachychampsa sealeyi differs from Brachychampsa montana, Albertochampsa langstoni, and other alligatoroids primarily in having an anteriorly tapering rostrum with a relatively reduced anterior dentition and smaller narial and incisive openings but relatively larger and more bulbous posterior teeth. The single associated osteoderm has a longitudinal keel and surfaces for articulation with overlapping osteoderms. Cladistic analysis suggests that ?B. sealeyi is a sister taxon to B. montana and supports the hypothesis that Brachychampsa and Albertochampsa form a monophyletic clade outside the Alligatoridae. Punctures on the mandible suggests that a bite was inflicted by another allig...", "keyphrases": ["brachychampsa sealeyi", "campanian", "northwestern new mexico"]}
{"id": "10.1073/pnas.0609662104", "title": "Paleobiology and comparative morphology of a late Neandertal sample from El Sidr\u00f3n, Asturias, Spain", "abstract": "Fossil evidence from the Iberian Peninsula is essential for understanding Neandertal evolution and history. Since 2000, a new sample \u224843,000 years old has been systematically recovered at the El Sidr\u00f3n cave site (Asturias, Spain). Human remains almost exclusively compose the bone assemblage. All of the skeletal parts are preserved, and there is a moderate occurrence of Middle Paleolithic stone tools. A minimum number of eight individuals are represented, and ancient mtDNA has been extracted from dental and osteological remains. Paleobiology of the El Sidr\u00f3n archaic humans fits the pattern found in other Neandertal samples: a high incidence of dental hypoplasia and interproximal grooves, yet no traumatic lesions are present. Moreover, unambiguous evidence of human-induced modifications has been found on the human remains. Morphologically, the El Sidr\u00f3n humans show a large number of Neandertal lineage-derived features even though certain traits place the sample at the limits of Neandertal variation. Integrating the El Sidr\u00f3n human mandibles into the larger Neandertal sample reveals a north\u2013south geographic patterning, with southern Neandertals showing broader faces with increased lower facial heights. The large El Sidr\u00f3n sample therefore augments the European evolutionary lineage fossil record and supports ecogeographical variability across Neandertal populations.", "keyphrases": ["neandertal sample", "asturias", "paleobiology"]}
{"id": "paleo.006612", "title": "Silurian thelodonts from the Niur Formation, central Iran", "abstract": "Thelodont scales are described from the Silurian Niur Formation in the Derenjal Mountains, east central Iran. The material studied herein comes from four stratigraphic levels, composed of rocks formed in a shallow water, carbonate ramp environment. The fauna includes a new phlebolepidiform, Niurolepis susanae gen. et sp. nov. of late Wenlock/?early Ludlow age and a late Ludlow loganelliiform, Loganellia sp. cf. L. grossi, which constitute the first record of these thelodont groups from Gondwana. The phlebolepidiform Niurolepis susanae gen. et sp. nov. is diagnosed by having trident trunk scales with a raised medial crown area separated by two narrow spiny wings from the lateral crown areas; a katoporodidtype histological structure distinguished by a network of branched wide dentine canals. Other scales with a notch on a smooth rhomboidal crown and postero-laterally down-stepped lateral rims have many characters in common with Loganellia grossi. Associated with the thelodonts are indeterminable acanthodian scales and a possible dentigerous jaw bone fragment. This finding also provides evidence of a hitherto unknown southward dispersal of Loganellia to the shelves of peri-Gondwana.", "keyphrases": ["niur formation", "iran", "unknown southward dispersal", "peri-gondwana"]}
{"id": "paleo.007444", "title": "Ediacaran discs from South America: probable soft-bodied macrofossils unlock the paleogeography of the Clymene Ocean", "abstract": "The origin, affinity and paleoecology of macrofossils of soft-bodied organisms of the terminal Ediacaran Period have been highly debated. Previous discoveries in South America are restricted to small shelly metazoans of the Nama Assemblage. Here we report for the first time the occurrence of discoidal structures from the Upper Ediacaran Cerro Negro Formation, La Providencia Group, Argentina. Specimens are preserved in tabular sandstones with microbially-induced sedimentary structures. Flute marks and linear scours at the base of the sandstone layers indicate deposition under high energy, episodic flows. Stratigraphic, sedimentologic, petrographic and taphonomic analyses indicate that the origin of these structures is not related to abiotic process. Preservational and morphological features, as invagination and the presence of radial grooves, indicate that they resemble typical morphs of the Aspidella plexus. The large number of small-sized individuals and the wide range of size classes with skewed distribution suggest that they lived in high-density communities. The presence of Aspidella in the Cerro Negro Formation would represent the first reliable record of Ediacaran soft-bodied organisms in South America. It also supports the paleogeographic scenario of the Clymene Ocean, in which a shallow sea covered part of the southwest Gondwana at the end of the Ediacaran.", "keyphrases": ["south america", "clymene ocean", "ediacaran disc"]}
{"id": "10.1080/08912963.2018.1506778", "title": "Dental homologies and evolutionary transformations in Caviomorpha (Hystricognathi, Rodentia): new data from the Paleogene of Peruvian Amazonia", "abstract": "ABSTRACT Dental homologies and evolutionary transformations within caviomorph rodents have long been disputed. Here, we participate in these debates in providing new insights from the dental morphology of Paleogene caviomorphs from Peruvian Amazonia (Contamana and Shapaja). Their analyses and comparisons with many hystricognaths allow (1) to generalize some hypotheses previously proposed about occlusal morphology of caviomorph cheek teeth, and (2) to propose new ones. In caviomorphs, the third crest of upper teeth would correspond either to a mesoloph or to a mesolophule or to a combination of both. The transformation from a pentalophodont pattern to a tetralophodont pattern would be explained by the disappearance of the metaloph. Likewise, the transformation from a tetralophodont pattern to a trilophodont pattern is observed by the loss of the third crest. A direct transformation from a pentalophodont pattern to a trilophodont pattern is also observed. Concerning lower teeth, discrepancies of homologies are centered on the mesial cristids, which can be notably distinguished depending on their compositions and connections with other structures. The ancestral patterns of caviomorph lower molars and dp4s were likely tetralophodont and pentalophodont, respectively. However, schemes with five and four (even three) transverse cristids cannot be ruled out for the two loci, respectively.", "keyphrases": ["evolutionary transformation", "peruvian amazonia", "dental homology"]}
{"id": "paleo.008045", "title": "The Integrated Plant Record (IPR) analysis: Methodological advances and new insights into the evolution of European Palaeogene/Neogene vegetation", "abstract": "The Integrated Plant Record (IPR) vegetation analysis serves as a proxy method to derive major types of zonal palaeovegetation based on the proportion of zonal key components. This paper pursues two goals: 1) to introduce two tools (Drudge 1 and Drudge 2) to statistically determine close modern proxies for fossil plant assemblages out of the reference set of currently 505 modern vegetation units. These range from closed forests to more open (steppe) environments from Europe and Asia and are based on the correspondence in the proportion of the zonal key components (IPR Similarity) and Taxonomic Similarity (TS, genus level); and 2) to present the extension of the calibration dataset of modern zonal vegetation using the natural vegetation of Europe, the Caucasus, China, and Mongolia. The tools are tested on six Central European plant assemblages from the late Eocene to the late Pliocene. For the late Eocene to early Miocene, the results indicate a close relationship to East Asian vegetation based both on IPR Similarity and TS. For the younger sites, IPR Similarity points towards European vegetation, whereas TS still indicates closer East Asian affinity. The summary results (as presented in the Results \u2013 Mix) derived by both tools deliver modern proxy vegetation units, which are in good agreement with modern vegetation analogues proposed by traditional empirical studies. The IPR Similarity results probably reflect climate change, which results in proportions of zonal key components, i.e., leaf physiognomy of zonal forests that are more similar to modern European than to Asian vegetation from the latest early/middle Miocene onwards. Vasilis Teodoridis. Department of Biology and Environmental Studies, Faculty of Education, Charles University, Prague, Czech Republic. vasilis.teodoridis@pedf.cuni.cz Petr Mazouch. Faculty of Informatics and Statistics, University of Economics, Prague, Czech Republic. mazouchp@vse.cz Johanna Kovar-Eder. State Museum of Natural History Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany. johanna.eder@smns-bw.de", "keyphrases": ["integrated plant record", "ipr", "vegetation"]}
{"id": "paleo.003108", "title": "Large\u2010scale evolutionary trends of Acrochordiceratidae Arthaber, 1911 (Ammonoidea, Middle Triassic) and Cope\u2019s rule", "abstract": "Abstract:\u2002 Directed evolution of life through millions of years, such as increasing adult body size, is one of the most intriguing patterns displayed by fossil lineages. Processes and causes of such evolutionary trends are still poorly understood. Ammonoids (externally shelled marine cephalopods) are well known to have experienced repetitive morphological evolutionary trends of their adult size, shell geometry and ornamentation. This study analyses the evolutionary trends of the family Acrochordiceratidae Arthaber, 1911 from the Early to Middle Triassic (251\u2013228\u2003Ma). Exceptionally large and bed\u2010rock\u2010controlled collections of this ammonoid family were obtained from strata of Anisian age (Middle Triassic) in north\u2010west Nevada and north\u2010east British Columbia. They enable quantitative and statistical analyses of its morphological evolutionary trends. This study demonstrates that the monophyletic clade Acrochordiceratidae underwent the classical evolute to involute evolutionary trend (i.e. increasing coiling of the shell), an increase in its shell adult size (conch diameter) and an increase in the indentation of its shell suture shape. These evolutionary trends are statistically robust and seem more or less gradual. Furthermore, they are nonrandom with the sustained shift in the mean, the minimum and the maximum of studied shell characters. These results can be classically interpreted as being constrained by the persistence and common selection pressure on this mostly anagenetic lineage characterized by relatively moderate evolutionary rates. Increasing involution of ammonites is traditionally interpreted by increasing adaptation mostly in terms of improved hydrodynamics. However, this trend in ammonoid geometry can also be explained as a case of Cope\u2019s rule (increasing adult body size) instead of functional explanation of coiling, because both shell diameter and shell involution are two possible paths for ammonoids to accommodate size increase.", "keyphrases": ["evolutionary trend", "middle triassic", "rule"]}
{"id": "10.1144/jgs.158.4.709", "title": "Biodiversity and terrestrial ecology of a mid-Cretaceous, high-latitude floodplain, Alexander Island, Antarctica", "abstract": "The biodiversity and terrestrial ecology of the Late Albian Triton Point Formation (Fossil Bluff Group), Alexander Island, Antarctica is analysed to improve our understanding of polar biomes during the mid-Cretaceous thermal optimum. This formation was deposited on a high-latitude (75\u00b0S) floodplain and consists of two facies associations, a lower braided alluvial plain unit and an upper coastal meander-belt unit. Analysis of fossil plants in well exposed palaeosols reveals the existence of spatially complex plant communities. Braidplains supported patchy, low-density (91\u2009trees/ha) stands of podocarp and taxodioid conifers on floodbasin substrates, and conifer\u2013cycadophyte\u2013fern\u2013angiosperm thickets in riparian settings. Coastal meander-belts supported medium density (568\u2009trees/ha) podocarp\u2013araucarian conifer forests on mature floodbasin soils, and fern\u2013angiosperm\u2013ginkgo thickets in riparian settings. Growth-ring analysis indicates plants experienced stressful growing conditions on the braidplain characterized by high-frequency flood events, but more favourable growing conditions on the coastal plain. Additional vegetation disturbances were caused by arthropod\u2013fungal attack, frost and wildfire. In terms of structure, composition, ecology and productivity these predominantly evergreen, broad-leafed conifer forests bear similarities to the extant temperate rainforests of New Zealand.", "keyphrases": ["terrestrial ecology", "floodplain", "alexander island", "temperate rainforest"]}
{"id": "10.1111/j.1502-3931.2012.00319.x", "title": "Phylogenetic analysis reveals that Rhabdopleura is an extant graptolite", "abstract": "A phylogenetic analysis of morphological data from modern pterobranch hemichordates (Cephalodiscus, Rhabdopleura) and representatives of each of the major graptolite orders reveals that Rhabdopleura nests among the benthic, encrusting graptolite taxa as it shares all of the synapomorphies that unite the graptolites. Therefore, rhabdopleurids can be regarded as extant members of the Subclass Graptolithina (Class Pterobranchia). Combined with the results of previous molecular phylogenetic studies of extant deuterostomes, these results also suggest that the Graptolithina is a sister taxon to the Subclass Cephalodiscida. The Graptolithina, as an important component of Early\u2013Middle Palaeozoic biotas, provide data critical to our understanding of early deuterostome phylogeny. This result allows one to infer the zooid morphology, mechanics of colony growth and palaeobiology of fossil graptolites in direct relation to the living members of the clade. The Subdivision Graptoloida (nom. transl.), which are all planktic graptolites, is well supported in this analysis. In addition, we recognize the clade Eugraptolithina (nov.). This clade comprises the Graptoloida and all of the other common and well-known graptolites of the distinctive Palaeozoic fauna. Most of the graptolites traditionally regarded as tuboids and dendroids appear to be paraphyletic groups within the Eugraptolithina; however, Epigraptus is probably not a member of this clade. The Eugraptolithina appear to be derived from an encrusting, Rhabdopleura-like species, but the available information is insufficient to resolve the phylogeny of basal graptolites. The phylogenetic position of Mastigograptus and the status of the Dithecoidea and Mastigograptida also remain unresolved. \u25a1 Biodiversity, Cambrian, Hemichordata, Deuterostomia, Ordovician.", "keyphrases": ["rhabdopleura", "graptolite", "extant member", "phylogenetic analysis", "fossil member"]}
{"id": "paleo.011263", "title": "Discontinuity of Human Presence at Atapuerca during the Early Middle Pleistocene: A Matter of Ecological Competition?", "abstract": "Increasing evidence suggests that the European human settlement is older than 1.2 Ma. However, there is a fierce debate about the continuity or discontinuity of the early human settlement of Europe. In particular, evidence of human presence in the interval 0.7\u22120.5 Ma is scarce in comparison with evidence for the previous and later periods. Here, we present a case study in which the environmental conditions at Sierra de Atapuerca in the early Middle Pleistocene, a period without evidence of human presence, are compared with the conditions in the previous period, for which a relatively intense human occupation is documented. With this objective in mind, the available resources for a human population and the intensity of competition between secondary consumers during the two periods are compared using a mathematical model. The Gran Dolina site TD8 level, dated to 0.7\u22120.6 Ma, is taken as representative of the period during which Atapuerca was apparently not occupied by humans. Conditions at TD8 are compared with those of the previous period, represented by the TD6-2 level, which has yielded abundant evidence of intense human occupation. The results show that survival opportunities for a hypothetical human population were lower at TD8 than they were at TD6-2. Increased resource competition between secondary consumers arises as a possible explanation for the absence of human occupation at Atapuerca in the early Middle Pleistocene.", "keyphrases": ["human presence", "atapuerca", "middle pleistocene"]}
{"id": "paleo.008345", "title": "Coupling of palaeontological and neontological reef coral data improves forecasts of biodiversity responses under global climatic change", "abstract": "Reef corals are currently undergoing climatically driven poleward range expansions, with some evidence for equatorial range retractions. Predicting their response to future climate scenarios is critical to their conservation, but ecological models are based only on short-term observations. The fossil record provides the only empirical evidence for the long-term response of organisms under perturbed climate states. The palaeontological record from the Last Interglacial (LIG; 125 000 years ago), a time of global warming, suggests that reef corals experienced poleward range shifts and an equatorial decline relative to their modern distribution. However, this record is spatio-temporally biased, and existing methods cannot account for data absence. Here, we use ecological niche modelling to estimate reef corals' realized niche and LIG distribution, based on modern and fossil occurrences. We then make inferences about modelled habitability under two future climate change scenarios (RCP4.5 and RCP8.5). Reef coral ranges during the LIG were comparable to the present, with no prominent equatorial decrease in habitability. Reef corals are likely to experience poleward range expansion and large equatorial declines under RCP4.5 and RCP8.5. However, this range expansion is probably optimistic in the face of anthropogenic climate change. Incorporation of fossil data in niche models improves forecasts of biodiversity responses under global climatic change.", "keyphrases": ["forecast", "biodiversity response", "climatic change"]}
{"id": "10.1029/2006PA001312", "title": "A multicoral calibration method to approximate a universal equation relating Sr/Ca and growth rate to sea surface temperature", "abstract": "[1]\u00a0Combining strontium-to-calcium ratios (Sr/Ca) with mean annual growth rates in Bermuda Diploria labyrinthiformis (brain corals) is shown to improve sea surface temperature (SST) calibrations relative to instrumental data. Growth-corrected Sr/Ca\u2013SST calibrations based on single-coral colonies over the same calibration interval, however, are found to be poorly suited for application to data from different coral colonies. This raises concerns about the accuracy of SST reconstructions from fossil coral measurements that involve extrapolation beyond the range of values seen during the calibration period. Here we pursue a novel approach to this problem by incorporating data from multiple coral colonies into a single growth-corrected Sr/Ca\u2013SST calibration equation, effectively expanding the range of modern values constraining the model. The use of a multiple-colony calibration model for reconstructing SST yields greater precision and accuracy relative to instrumental data than single-colony models, providing greater confidence for applications to fossil coral samples.", "keyphrases": ["growth rate", "sea surface temperature", "application"]}
{"id": "paleo.006673", "title": "An exceptional fossil skull from South America and the origins of the archosauriform radiation", "abstract": "Birds, dinosaurs, crocodilians, pterosaurs and their close relatives form the highly diverse clade Archosauriformes. Archosauriforms have a deep evolutionary history, originating in the late Permian, prior to the end-Permian mass extinction, and radiating in the Triassic to dominate Mesozoic ecosystems. However, the origins of this clade and its extraordinarily successful body plan remain obscure. Here, we describe an exceptionally preserved fossil skull from the Lower Triassic of Brazil, representing a new species, Teyujagua paradoxa, transitional in morphology between archosauriforms and more primitive reptiles. This skull reveals for the first time the mosaic assembly of key features of the archosauriform skull, including the antorbital and mandibular fenestrae, serrated teeth, and closed lower temporal bar. Phylogenetic analysis recovers Teyujagua as the sister taxon to Archosauriformes, and is congruent with a two-phase model of early archosauriform evolution, in response to two mass extinctions occurring at the end of the Guadalupian and the Permian.", "keyphrases": ["fossil skull", "archosauriformes", "brazil"]}
{"id": "10.1111/j.1095-8312.2011.01843.x", "title": "Mandibular shape correlates of tooth fracture in extant Carnivora: implications to inferring feeding behaviour of Pleistocene predators", "abstract": "Percentages of tooth fracture and mandible shape are robust predictors of feeding habits in Carnivora. If these parameters co-vary above the species level, more robust palaeobiological inferences could be made on fossil species. A test of association is presented between mandible shape and tooth fracture in a subset of extant carnivorans together with large Pleistocene fossil predators from Rancho La Brea (Canis dirus, Panthera atrox, and Smilodon fatalis). Partial least square (PLS) and comparative methods are employed to validate co-variation of these two parameters in extant carnivorans. Association between mandible shape and percentage of tooth fracture is strongly supported, even if both blocks of data exhibit a phylogenetic signal to a different degree. Dietary adaptations drive shape/fracture co-variation in extant species, although no significant differences occur in the PLS scores between carnivores and bone/hard food consumers. The fossil species project into PLS morphospace as outliers. Their position suggests a unique feeding behaviour. The increase in the size of prey, together with consumption of skin and hair from carcasses in a cold environment, might have generated unusual tooth breakage patterns in large predators from Rancho La Brea.\u00a0\u00a9 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 70\u201380.", "keyphrases": ["tooth fracture", "carnivora", "behaviour"]}
{"id": "paleo.003168", "title": "Recent inner ear specialization for high-speed hunting in cheetahs", "abstract": "The cheetah, Acinonyx jubatus, is the fastest living land mammal. Because of its specialized hunting strategy, this species evolved a series of specialized morphological and functional body features to increase its exceptional predatory performance during high-speed hunting. Using high-resolution X-ray computed micro-tomography (\u03bcCT), we provide the first analyses of the size and shape of the vestibular system of the inner ear in cats, an organ essential for maintaining body balance and adapting head posture and gaze direction during movement in most vertebrates. We demonstrate that the vestibular system of modern cheetahs is extremely different in shape and proportions relative to other cats analysed (12 modern and two fossil felid species), including a closely-related fossil cheetah species. These distinctive attributes (i.e., one of the greatest volumes of the vestibular system, dorsal extension of the anterior and posterior semicircular canals) correlate with a greater afferent sensitivity of the inner ear to head motions, facilitating postural and visual stability during high-speed prey pursuit and capture. These features are not present in the fossil cheetah A. pardinensis, that went extinct about 126,000 years ago, demonstrating that the unique and highly specialized inner ear of the sole living species of cheetah likely evolved extremely recently, possibly later than the middle Pleistocene.", "keyphrases": ["high-speed hunting", "cheetah", "vestibular system", "proportion", "stability"]}
{"id": "10.1021/ar200209k", "title": "A modular hierarchy-based theory of the chemical origins of life based on molecular complementarity.", "abstract": "Albert Szent-Gyorgyi once defined discovery as seeing what everyone else sees and thinking what no one else thinks. I often find that phenomena that are obvious to other people are not obvious to me. Molecular complementarity is one of these phenomena: while rare among any random set of compounds, it is ubiquitous in living systems. Because every molecule in a living system binds more or less specifically to several others, we now speak of \"interactomes\". What explains the ubiquity of molecular complementarity in living systems? What might such an explanation reveal about the chemical origins of life and the principles that have governed its evolution? Beyond this, what might complementarity tell us about the optimization of integrated systems in general? My research combines theoretical and experimental approaches to molecular complementarity relating to evolution from prebiotic chemical systems to superorganismal interactions. Experimentally, I have characterized complementarity involving specific binding between small molecules and explored how these small-molecule modules have been incorporated into macromolecular systems such as receptors and transporters. Several general principles have emerged from this research. Molecules that bind to each other almost always alter each other's physiological effects; and conversely, molecules that have antagonistic or synergistic physiological effects almost always bind to each other. This principle suggests a chemical link between biological structure and function. Secondly, modern biological systems contain an embedded molecular paleontology based on complementarity that can reveal their chemical origins. This molecular paleontology is often manifested through modules involving small, molecularly complementary subunits that are built into modern macromolecular structures such as receptors and transporters. A third principle is that complementary modules are conserved and repurposed at every stage of evolution. Molecular complementarity plays critical roles in the evolution of chemical systems and resolves a significant number of outstanding problems in the emergence of complex systems. All physical and mathematical models of organization within complex systems rely upon nonrandom linkage between components. Molecular complementarity provides a naturally occurring nonrandom linker. More importantly, the formation of hierarchically organized stable modules vastly improves the probability of achieving self-organization, and molecular complementarity provides a mechanism by which hierarchically organized stable modules can form. Finally, modularity based on molecular complementarity produces a means for storing and replicating information. Linear replicating molecules such as DNA or RNA are not required to transmit information from one generation of compounds to the next: compositional replication is as ubiquitous in living systems as genetic replication and is equally important to its functions. Chemical systems composed of complementary modules mediate this compositional replication and gave rise to linear replication schemes. In sum, I propose that molecular complementarity is ubiquitous in living systems because it provides the physicochemical basis for modular, hierarchical ordering and replication necessary for the evolution of the chemical systems upon which life is based. I conjecture that complementarity more generally is an essential agent that mediates evolution at every level of organization.", "keyphrases": ["chemical origin", "molecular complementarity", "molecular paleontology"]}
{"id": "10.2478/v10118-009-0002-1", "title": "Easily-accessible digital palaeontological databases-a new perspective for the storage of palaeontological information", "abstract": "Easily-accessible digital palaeontological databases-a new perspective for the storage of palaeontological information Techniques that allow to render diverse types of palaeontological data as publicly available internet resources are described. In order to develop an easily accessible digital palaeontological database, three steps should be followed: (1) digitization of the studied specimens, (2) acquisition of morphometric data, and (3) contribution of the data to open and searchable geoinformatic (palaeontological) databases. Digital data should be submitted to internet databases that allow a user to fetch various types of information from dispersed sources (semantic web services).", "keyphrases": ["digital palaeontological databases-a", "digitization", "new perspective", "storage"]}
{"id": "10.1029/2007GC001686", "title": "Correlation of boron isotopic composition with ultrastructure in the deep\u2010sea coral Lophelia pertusa: Implications for biomineralization and paleo\u2010pH", "abstract": "Using the CRPG\u2010CNRS Cameca 1270 ion microprobe facility, we have measured boron isotopic compositions (11B/10B) in different ultrastructural components of the deep\u2010sea aragonitic scleractinian coral Lophelia pertusa. We observe a systematic difference in B isotopic composition between the Early Mineralization Zone (EMZ) and adjacent fibrous skeleton. In EMZ the measured \u03b411B values are consistently low. Fibrous aragonite is characterized by systematically higher \u03b411B values but also displays B isotopic heterogeneity associated with specific growth bands in the calyx wall. The magnitude of the observed B isotopic variations cannot be explained by changes in environmental conditions and is likely caused by biological processes involved in the biomineralization of new skeleton, i.e., \u201cvital\u201d effects. The observed B isotopic variations are opposite to the predictions of geochemical models for vital effects. These models are based on the idea that stable isotopic fractionations (including C and O) in coral skeleton are driven by changes in pH of the fluid from which the skeleton is presumed to precipitate. Our data indicate that pH variations are not responsible for the observed stable isotopic fractionations. Geochemical models therefore do not provide an adequate framework within which to understand coral skeletal formation. Without a better understanding of these processes the use of B isotopic composition to reconstruct paleo\u2010pH variations in the oceans must be considered problematic, at least as far as Lophelia pertusa is concerned.", "keyphrases": ["boron", "isotopic composition", "biomineralization"]}
{"id": "10.1080/02724634.2016.1160910", "title": "A New Caenagnathid (Dinosauria: Oviraptorosauria) from the Horseshoe Canyon Formation of Alberta, Canada, and a Reevaluation of the Relationships of Caenagnathidae", "abstract": "ABSTRACT Our understanding of caenagnathids has benefited from recent discoveries, including nearly complete skeletons from the Hell Creek Formation of Montana. However, their phylogenetic relationships remain unclear. A new specimen from the Horseshoe Canyon Formation of Alberta has implications for the phylogeny and paleobiology of these creatures. The partial skeleton is articulated and includes a mandible, a full cervical and dorsal series of vertebrae, a right pectoral girdle and arm, a sternum, gastralia, a partial ilium, and a partial hind limb. The mandible is edentulous and the articular ridge is intermediate in form between Caenagnathus collinsi and Chirostenotes pergracilis. The neck is long and composed of at least 11 well-pneumatized cervical vertebrae with fused cervical ribs. The dorsal ribs have finger-like uncinate processes dissimilar in shape to those of other oviraptorosaurs. The pectoral girdle is large and typically maniraptoran, except that the glenoid of the scapulocoracoid faces laterally instead of posteroventrally. The arm is well muscled and can be interpreted to have been a pennibrachium, as indicated by ulnar papillae on the ulna. The manus is characterized by a short first metacarpal but an elongate phalanx I-1 and oviraptorid-like phalangeal proportions in the second digit. These and other features indicate that the specimen represents a new taxon, Apatoraptor pennatus, gen. et sp. nov. Phylogenetic analysis resolves the complicated relationships of Caenagnathidae and allows the evolution of display features to be traced throughout Oviraptorosauria.", "keyphrases": ["caenagnathid", "oviraptorosauria", "caenagnathidae"]}
{"id": "10.1098/rspb.2010.1641", "title": "Decay of vertebrate characters in hagfish and lamprey (Cyclostomata) and the implications for the vertebrate fossil record", "abstract": "The timing and sequence of events underlying the origin and early evolution of vertebrates remains poorly understood. The palaeontological evidence should shed light on these issues, but difficulties in interpretation of the non-biomineralized fossil record make this problematic. Here we present an experimental analysis of decay of vertebrate characters based on the extant jawless vertebrates (Lampetra and Myxine). This provides a framework for the interpretation of the anatomy of soft-bodied fossil vertebrates and putative cyclostomes, and a context for reading the fossil record of non-biomineralized vertebrate characters. Decay results in transformation and non-random loss of characters. In both lamprey and hagfish, different types of cartilage decay at different rates, resulting in taphonomic bias towards loss of \u2018soft\u2019 cartilages containing vertebrate-specific Col2\u03b11 extracellular matrix proteins; phylogenetically informative soft-tissue characters decay before more plesiomorphic characters. As such, synapomorphic decay bias, previously recognized in early chordates, is more pervasive, and needs to be taken into account when interpreting the anatomy of any non-biomineralized fossil vertebrate, such as Haikouichthys, Mayomyzon and Hardistiella.", "keyphrases": ["vertebrate character", "hagfish", "lamprey"]}
{"id": "10.1002/2013PA002509", "title": "Weakening and strengthening of the Indian monsoon during Heinrich events and Dansgaard-Oeschger oscillations", "abstract": "The Dansgaard-Oeschger oscillations and Heinrich events described in North Atlantic sediments and Greenland ice are expressed in the climate of the tropics, for example, as documented in Arabian Sea sediments. Given the strength of this teleconnection, we seek to reconstruct its range of environmental impacts. We present geochemical and sedimentological data from core SO130-289KL from the Indus submarine slope spanning the last similar to 80 kyr. Elemental and grain size analyses consistently indicate that interstadials are characterized by an increased contribution of fluvial suspension from the Indus River. In contrast, stadials are characterized by an increased contribution of aeolian dust from the Arabian Peninsula. Decadal-scale shifts at climate transitions, such as onsets of interstadials, were coeval with changes in productivity-related proxies. Heinrich events stand out as especially dry and dusty events, indicating a dramatically weakened Indian summer monsoon, potentially increased winter monsoon circulation, and increased aridity on the Arabian Peninsula. This finding is consistent with other paleoclimate evidence for continental aridity in the northern tropics during these events. Our results strengthen the evidence that circum-North Atlantic temperature variations translate to hydrological shifts in the tropics, with major impacts on regional environmental conditions such as rainfall, river discharge, aeolian dust transport, and ocean margin anoxia. Key Points Intensity of Indian monsoon is traced with geochemical and grain size analyses of sediments Fluvial versus aeolian sediment input to Arabian Sea mimics DO oscillations During Heinrich events the Indian monsoon weakened distinctly", "keyphrases": ["monsoon", "heinrich event", "dansgaard-oeschger oscillation"]}
{"id": "10.1177/0959683615580861", "title": "The seasonal water temperature cycle in the Arctic Dicksonfjord (Svalbard) during the Holocene Climate Optimum derived from subfossil Arctica islandica shells", "abstract": "Future climate change will have significant effects on ecosystems worldwide and on polar regions in particular. Hence, palaeo-environmental studies focussing on the last warmer-than-today phase (i.e. the early Holocene) in higher latitudes are of particular importance to understand climate development and its potential impact in polar systems. Molluscan bivalve shells constitute suitable bio-archives for high-resolution palaeo-environmental reconstructions. Here, we present a first reconstruction of early Holocene seasonal water temperature cycle in an Arctic fjord based on stable oxygen isotope (\u03b418Oshell) profiles in shells of Arctica islandica (Bivalvia) from raised beach deposits in Dicksonfjorden, Svalbard, dated at 9954\u20139782 cal. yr BP. Reconstructed maximum and minimum bottom water temperatures for the assumed shell growth period between April and August of 15.2\u00b0C and 2.8\u00b0C imply a seasonality of about 12.4\u00b0C for the early Holocene. In comparison to modern temperatures, this indicates that average temperature declined by 6\u00b0C and seasonality narrowed by 50%. This first palaeo-environmental description of a fjord setting during the Holocene Climate Optimum at Spitsbergen exceeds most previous global estimates (+1\u20133\u00b0C) but confirms studies indicating an amplified effect (+4\u20136\u00b0C) at high northern latitudes.", "keyphrases": ["seasonality", "water temperature cycle", "holocene climate optimum"]}
{"id": "10.1002/spp2.1276", "title": "Cranial osteology of the Middle Jurassic (Callovian) Martillichthys renwickae (Neopterygii, Pachycormiformes) with comments on the evolution and ecology of edentulous pachycormiforms", "abstract": "Our understanding of the ecology and phylogenetic relationships of Pachycormiformes, a group of Mesozoic stem teleosts including the iconic Leedsichthys, has often been hindered by a lack of comprehensive morphological information. Micro\u2010CT scanning of an articulated, although flattened, cranium of the edentulous Martillichthys renwickae from the Middle Jurassic (Callovian) Oxford Clay of the UK reveals previously unknown internal details of the most complete suspension\u2010feeding pachycormiform skull known, including the palate, braincase and branchial skeleton. The latter preserves gill rakers with elongate, pointed projections similar to those of Asthenocormus, in contrast to the finer fimbriations associated with Leedsichthys. We also reinterpret some previously described features, including dermal bone patterns of the snout, skull roof and lower jaw, and the morphology of the ventral hyoid arch. These new anatomical data reinforce the phylogenetic placement of Martillichthys as part of the Jurassic clade of edentulous pachycormiforms. The elongate skull geometry of these Jurassic taxa is strikingly similar to that of Ohmdenia, the sister taxon to edentulous pachycormiforms, but contrasts sharply with the morphology of the Late Cretaceous edentulous pachycormiform Bonnerichthys, raising questions over the phylogenetic relationships among these taxa. Most significantly, Martillichthys shows specialized characters with a restricted phylogenetic distribution among suspension\u2010feeding pachycormiforms, including the distinctive gill rakers and a greatly extended occipital stalk. Our analysis of Martillichthys supports past interpretations of a close relationship with Asthenocormus, and provides a model for interpreting the less complete remains of other members of this enigmatic group of fishes.", "keyphrases": ["martillichthys renwickae", "pachycormiformes", "edentulous pachycormiform"]}
{"id": "10.1080/14772019.2016.1164763", "title": "A new Permian temnospondyl with Russian affinities from South America, the new family Konzhukoviidae, and the phylogenetic status of Archegosauroidea", "abstract": "A new Permian temnospondyl from South America is described and considered to represent a new species \u2013 Konzhukovia sangabrielensis sp. nov. \u2013 of the genus Konzhukovia previously recorded exclusively from Russia. It consists of the anterior half and partial right side of the skull roof and palate. A comprehensive phylogenetic analysis was performed with several archegosauroids and other well-supported groups of temnospondyls in order to access the affinities of the new Brazilian species and test the monophyly of Archegosauroidea. Archegosauroidea was not recovered as a monophyletic group, comprising successive paraphyletic taxa. The only monophyletic group of \u2018archegosauroids\u2019 is the \u2018Tryphosuchinae\u2019 (in a sister-group relationship with Stereospondyli), composed of Tryphosuchus paucidens, Konzhukovia vetusta, K. tarda and K. sangabrielensis. As the diagnosis of T. paucidens is unclear and based on incomplete material, nested among three species of Konzhukovia, we consider this taxon to be a nomen dubium and purge it from the strict consensus tree. An alternative solution would be to erect a new taxonomic combination for T. paucidens. In order to solve these taxonomic problems, it is necessary to discover more complete material with a clear set of diagnostic characters, to either revalidate this taxon or provide a new combination for it. The phylogenetic results support the erection of a new family \u2013 Konzhukoviidae \u2013 to replace \u2018Tryphosuchinae\u2019 and accommodate Konzhukovia vetusta, K. tarda and K. sangabrielensis, the new Brazilian species basal to the Russian forms. An early diverging konzhukoviid in Gondwana leads to interesting insights regarding the evolution of the new family, stereospondyl origins, their early diversification and their palaeobiogeographical patterns of distribution. http://zoobank.org/urn:lsid:zoobank.org:pub:4772DC7E-C427-4F5F-89FD-9E68E3B0BFD5", "keyphrases": ["new permian temnospondyl", "south america", "archegosauroidea"]}
{"id": "10.1029/1999PA000495", "title": "The last 18 kyr fluctuations in Norwegian sea surface conditions and implications for the magnitude of climatic change: Evidence from the North Sea", "abstract": "A combined record of three cores spanning the last 18 kyr from the northern North Sea is investigated for content of benthic and planktonic foraminifera and stable oxygen isotopes. The paleoenvironmental development through this time period shows an early deglaciation (18\u201314.4 ka) and the Younger Dryas (12.7\u201311.5 ka) characterized by arctic/polar conditions and increased ice rafting in the Norwegian Channel. During the Bolling-Allerod period, warm sea surface temperature (9\u00b0C) conditions similar to present conditions are inferred, while bottom waters stayed cold (0\u20131\u00b0C) with normal salinity. The Bolling-Allerod period is interrupted twice at 13.9\u201313.6 ka (Older Dryas) and at 13.0\u201312.8 ka (Inter-Allerod Cooling Period) by reductions in sea surface temperatures and increased sea ice cover. The beginning of the Holocene period is marked by increases in surface and bottom water temperature. Superimposed on the broad climatic changes through the Holocene, a series of short-lived oscillations in the ocean circulation are recorded. The amplitude of these Holocene events appears larger in the early Holocene (prior to 8 ka) than compared with the remaining part of the Holocene. This amplification can possibly be attributed to a general increased freshwater budget in the North Atlantic at this time during the final stages of the deglaciation of the Laurentide and Scandinavian ice sheets.", "keyphrases": ["climatic change", "north sea", "early holocene"]}
{"id": "10.1111/j.1502-3931.2010.00251.x", "title": "Plant and animal cuticle remains from the Lower Devonian of southern Poland and their palaeoenvironmental significance", "abstract": "Filipiak, P. & Zaton, M. 2010: Plant and animal cuticle remains from the Lower Devonian of southern Poland and their palaeoenvironmental significance. Lethaia, Vol. 44, pp. 397\u2013409. \n \n \n \nAssemblages of plant and arthropod remains are reported from the Lower Devonian clastic deposits of the Upper Silesian and Malopolska blocks in southern Poland. Most of the plant and animal remains are palynologically dated as Pragian\u2013Emsian/Eifelian. The plant material comprises higher plant cuticles with stomata classified as Drephanophycus and Sawdonia, and more enigmatic remains (nematophytes) classified as Nematothallus, Cosmochlaina and tubular banded tubes. They are associated with abundant and diverse miospores. Animal remains consist of eurypterid respiratory organs, the morphology of which may presumably point to their advance physiological properties, and cuticular remains of eurypterid and probably scorpion origin, as well as some remains of unknown affinity. The presence of such mixed assemblages in the Lower Devonian of Poland indicate marginal-marine and/or alluvial environments spreading in the southern margin of the Old Red Continent. The dominance of land-derived plant remains and simultaneous scarcity of marine acritarchs indicate that the environment was very weakly influenced by marine conditions. If nematophytes were really related to extant liverworts, as suggested by some workers, they, together with the other associated spore-producing plants, may strongly indicate moist environmental conditions, which may have offered suitable habitats for temporary eurypterid migrations onto land.\u00a0\u25a1Cuticles, eurypterids, Lower Devonian, nematophytes, Poland, spores.", "keyphrases": ["animal cuticle", "southern poland", "palaeoenvironmental significance"]}
{"id": "10.1017/pab.2017.36", "title": "Intraspecific variation in cephalopod conchs changes during ontogeny: perspectives from three-dimensional morphometry of Nautilus pompilius", "abstract": "Abstract. \n Intraspecific variation of organisms is of great importance to correctly carry out taxonomic work, which is a prerequisite for key disciplines in paleontology such as community paleoecology, biostratigraphy, and biogeography. However, intraspecific variation is rarely studied in ectocochleate cephalopods (ammonoids and nautiloids), for which an excessive number of taxa was established during the past centuries. Because intraspecific variation of fossilized organisms suffers from various biases (time averaging and taphonomy), an extant example is needed for actualistic comparison. We applied 3D morphometry to 93 specimens of Nautilus pompilius from three different geographic populations. This data set was used to examine the intraspecific variation throughout ontogeny in detail. Although there are slight differences between the populations as well as some measurement biases, a common pattern of intraspecific variation appears to be present. High variation in morphometric variables appears early in ontogeny and then decreases gradually in the following ontogenetic stages. Subsequently, the variation shows an increase again before maturity until a sharp increase or decrease occurs toward the end of ontogeny. Comparison with intraspecific variation of ammonoids and belemnites illustrated that some groups have ontogenetic patterns of intraspecific variation that are similar to that of N. pompilius. This implies that the abovementioned ontogenetic pattern of intraspecific variation might be common in some major cephalopod clades.", "keyphrases": ["morphometry", "pompilius", "intraspecific variation"]}
{"id": "paleo.007567", "title": "Dental and tarsal morphology of the European Paleocene/Eocene \"condylarth\" mammal Microhyus", "abstract": "New dental and postcranial remains of the alleged louisinine hyopsodontid \"condylarth\" Microhyus from the European Paleocene/Eocene transition are described, and prompt a reevaluation of the genus. New specimens belonging to Microhyus musculus from Dormaal (MP7, Belgium) provide the first evidence of the lower dentition of the type species. We describe M. musculus? from Pourcy (MP7, France) and cf. Microhyus sp. from Berru (MP6a, France). A rich original assemblage of M. reisi from Silveirinha (MP7, Portugal) allows a detailed description of the morphological dental variation within that species. Well-preserved astragali and calcanei from Silveirinha can be confidently attributed to Microhyus reisi. Functional analysis of these elements suggests that Microhyus was a terrestrial mammal capable of rapid running or jumping. The pedal morphology of Microhyus is very similar to that of Paschatherium. These louisinines share some derived characters with the hyopsodontids Apheliscus and Haplomylus (e.g., the occurrence of a cotylar fossa on the astragalus) but they differ from Hyopsodus. Therefore, in view of the pedal morphology alone, the hyopsodontids may be polyphyletic. Given the dental similarities between Microhyus and the early representatives of the order Macroscelidea, we compared the tarsal morphology of louisinines with that of modern macroscelidids (Paleogene tarsal remains are currently unknown for this group). Macroscelidids and louisinines present some similarities in their astragalar morphology; however, the macroscelidid astragalus appears to be too specialized to be compared with that of Microhyus and Paschatherium.", "keyphrases": ["tarsal morphology", "european paleocene", "condylarth"]}
{"id": "paleo.002103", "title": "Development and trunk segmentation of early instars of a ptychopariid trilobite from Cambrian Stage 5 of China", "abstract": "Many three-dimensionally preserved exoskeletons found from the middle Cambrian (Stage 5) Gaotai Formation in Guizhou, southern China, have been assigned to the ptychopariid trilobite Gunnia sp. They represent mainly a series of early instars, exhibiting some delicate structures and morphological variation associated with their trunk segmentation and early development. Morphometric and statistical analyses indicate that the transverse joint appears to occur with the full growth of the third axial ring of the protopygidium, which increases in size much more rapidly than its corresponding protocephalon with growth. The \u2018one by one' sequential release of thoracic segments from a transitory pygidium does not progress exactly in accordance with the development of the pygidial axis, whose axial rings increase at a relatively faster rate, and an \u2018immature ring' always appears initially at the rear end of the axis. These new data set up a testable model for revealing trilobite segmentation and provide fresh insights into the development, evolution and taphonomic surroundings associated with the Cambrian trilobites.", "keyphrases": ["trunk segmentation", "early instar", "trilobite"]}
{"id": "10.1111/pala.12589", "title": "How to date a crocodile: estimation of neosuchian clade ages and a comparison of four time\u2010scaling methods", "abstract": "Clade ages within the crocodylomorph clade Neosuchia have long been debated. Molecular and morphological studies have yielded remarkably divergent results. Despite recent advances, there has been no comprehensive relative comparison of the major time calibration methods available to estimate clade ages based on morphological data. We used four methods (cal3, extended Hedman, smoothed ghost lineage analysis (sGLA) and the fossilized birth\u2013death model (FBD)) to date clade ages derived from a published crocodylomorph supertree and a new neosuchian phylogeny. All time\u2010scaling methods applied here agree on the origination of Neosuchia during the Late Triassic or Early Jurassic, and the presence of the major extant eusuchian groups (Crocodyloidea, Gavialoidea, Alligatoroidea and Caimaininae) by the end of the Late Cretaceous. The number of distinct lineages present before the K/Pg boundary is less certain, with support for two competing scenarios in which Crocodylinae, Tomistominae and Diplocynodontinae either: (1) diverged from other eusuchian lineages before the K/Pg boundary; or (2) evolved during a \u2018burst\u2019 of diversification after the K/Pg event. Cal3 and FBD proved to be the most suitable methods for time\u2010scaling phylogenetic trees dominated by fossil taxa. Extended Hedman estimates are substantially older than the others, with larger standard deviations and a strong sensitivity to taxon sampling and topological changes; sGLA has similar problems. We conclude that a detailed understanding of phylogenetic relationships, tree reconstruction methods, and good taxonomic coverage (in particular the inclusion of the oldest taxon in each clade) is essential when evaluating the results of such dating analyses.", "keyphrases": ["clade age", "time\u2010scaling method", "neosuchia"]}
{"id": "10.1126/science.223.4641.1177", "title": "Terminal Cretaceous Extinctions in the Hell Creek Area, Montana: Compatible with Catastrophic Extinction", "abstract": "Inaccurate stratigraphic correlations in the Hell Creek area, Montana, have led to the assumption that transitional vertebrate faunas (Bug Creek Anthills) exist in the latest Cretaceous, refuting a catastrophic turnover at the Cretaceous-Tertiary boundary. Establishment of the transitional faunas in Paleocene channels that cut down through the Cretaceous-Tertiary boundary renders the terrestrial faunal record compatible with the marine record and with catastrophic extinction.", "keyphrases": ["hell creek area", "montana", "catastrophic extinction"]}
{"id": "10.1080/11035890101233169", "title": "Late Silurian reef development in the Baltic Sea", "abstract": "Abstract In the Baltic Sea, reef structures are common in the Ordovician and Silurian sedimentary bedrock. Palaeozoic reef development culminated in the Silurian when several successive reef barriers developed. The present investigation has revealed new reef structures in the upper Silurian sedimentary bedrock. Two new biostromes, E1 and E2, have been found in the Ludlovian Eke Beds, east of Gotland. The biostromes trend in a more or less east-west direction and can be traced across the northern part of the Baltic Sea. In the Pridolian, two reef-like barriers, named B5 and B6, occur at the boundary to the Devonian. The lower barrier, B5, is found to the south of the younger B6 barrier. This indicates that a transgression occurred between the formation of the two barriers. A tentative reconstruction of the Pridolian bay suggests that the coast shifted from a more east-west direction in the Ludlovian to a more north-easterly to south-westerly direction in the Pridolian. Bioherms are commonly associated with the Eke biostromes and the upper Pridolian reef-like barriers. The bioherms occur on the seaward side of the larger reef structures, on the biohermal slope. Patch-reefs also occur on the biohermal slope but they are more common on the landward (lagoonal) side of the barriers.", "keyphrases": ["reef development", "baltic sea", "gotland"]}
{"id": "paleo.009358", "title": "Blade and bladelet production at Hohle Fels Cave, AH IV in the Swabian Jura and its importance for characterizing the technological variability of the Aurignacian in Central Europe", "abstract": "Hohle Fels Cave in the Ach Valley of Southwestern Germany exhibits an Aurignacian sequence of 1 m thickness within geological horizons (GH) 6\u20138. The deposition of the layers took place during mild and cold phases between at least 42 ka (GI 10) and 36 ka calBP (GI 7). We present below a technological study of blade and bladelet production from AH IV (GH 7) at Hohle Fels. Our analyses show that blade manufacture is relatively constant, while bladelet production displays a high degree of variability in order to obtain different blanks. Knappers used a variety of burins as cores to produce fine bladelets. The results reveal a new variant of the Aurignacian in the Swabian Jura primarily characterized by the production of bladelets and microliths from burin-cores. The artefacts from the Swabian Aurignacian are technologically and functionally more diverse than earlier studies of the Gei\u00dfenkl\u00f6sterle and Vogelherd sequences have suggested. The technological analyses presented here challenge the claim that the typo-chronological system from Southwestern Europe can be applied to the Central European Aurignacian. Instead, we emphasize the impact of technological and functional variables within the Aurignacian of the Swabian Jura.", "keyphrases": ["bladelet production", "swabian jura", "aurignacian"]}
{"id": "paleo.006150", "title": "Spatial sampling heterogeneity limits the detectability of deep time latitudinal biodiversity gradients", "abstract": "The latitudinal biodiversity gradient (LBG), in which species richness decreases from tropical to polar regions, is a pervasive pattern of the modern biosphere. Although the distribution of fossil occurrences suggests this pattern has varied through deep time, the recognition of palaeobiogeographic patterns is hampered by geological and anthropogenic biases. In particular, spatial sampling heterogeneity has the capacity to impact upon the reconstruction of deep time LBGs. Here we use a simulation framework to test the detectability of three different types of LBG (flat, unimodal and bimodal) over the last 300 Myr. We show that heterogeneity in spatial sampling significantly impacts upon the detectability of genuine LBGs, with known biodiversity patterns regularly obscured after applying the spatial sampling window of fossil collections. Sampling-standardization aids the reconstruction of relative biodiversity gradients, but cannot account for artefactual absences introduced by geological and anthropogenic biases. Therefore, we argue that some previous studies might have failed to recover the \u2018true\u2019 LBG type owing to incomplete and heterogeneous sampling, particularly between 200 and 20 Ma. Furthermore, these issues also have the potential to bias global estimates of past biodiversity, as well as inhibit the recognition of extinction and radiation events.", "keyphrases": ["sampling", "heterogeneity", "deep time", "latitudinal biodiversity gradient"]}
{"id": "10.1029/2019GL083574", "title": "Climate Sensitivity on Geological Timescales Controlled by Nonlinear Feedbacks and Ocean Circulation", "abstract": "Climate sensitivity is a key metric used to assess the magnitude of global warming given increased CO2 concentrations. The geological past can provide insights into climate sensitivity; however, on timescales of millions of years, factors other than CO2 can drive climate, including paleogeographic forcing and solar luminosity. Here, through an ensemble of climate model simulations covering the period 150\u201335 million years ago, we show that climate sensitivity to CO2 doubling varies between \u223c3.5 and 5.5 \u00b0C through this time. These variations can be explained as a nonlinear response to solar luminosity, evolving surface albedo due to changes in ocean area, and changes in ocean circulation. The work shows that the modern climate sensitivity is relatively low in the context of the geological record, as a result of relatively weak feedbacks due to a relatively low CO2 baseline, and the presence of ice and relatively small ocean area in the modern continental configuration.", "keyphrases": ["ocean circulation", "ensemble", "climate sensitivity"]}
{"id": "paleo.012295", "title": "The earliest segmental sternum in a Permian synapsid and its implications for the evolution of mammalian locomotion and ventilation", "abstract": "The sternum is a stabilizing element in the axial skeleton of most tetrapods, closely linked with the function of the pectoral girdle of the appendicular skeleton. Modern mammals have a distinctive sternum characterized by multiple ossified segments, the origins of which are poorly understood. Although the evolution of the pectoral girdle has been extensively studied in early members of the mammalian total group (Synapsida), only limited data exist for the sternum. Ancestrally, synapsids exhibit a single sternal element and previously the earliest report of a segmental sternum in non-mammalian synapsids was in the Middle Triassic cynodont Diademodon tetragonus. Here, we describe the well-preserved sternum of a gorgonopsian, a group of sabre-toothed synapsids from the Permian. It represents an ossified, multipartite element resembling the mammalian condition. This discovery pulls back the origin of the distinctive \u201cmammalian\u201d sternum to the base of Theriodontia, significantly extending the temporal range of this morphology. Through a review of sternal morphology across Synapsida, we reconstruct the evolutionary history of this structure. Furthermore, we explore its role in the evolution of mammalian posture, gait, and ventilation through progressive regionalization of the postcranium as well as the posteriorization of musculature associated with mammalian breathing.", "keyphrases": ["segmental sternum", "synapsid", "ventilation"]}
{"id": "10.1073/pnas.2019158118", "title": "Ancient DNA and multimethod dating confirm the late arrival of anatomically modern humans in southern China", "abstract": "Significance Genetic studies show the founders of all living non-African populations expanded from Africa ca. 65 to 45 ka. This \u201clate dispersal\u201d model has been challenged by the discovery of isolated AMHs at caves in southern China suggested as early as ca. 120 ka. We assessed the age of early AMH fossils from five caves in this region using ancient DNA analysis and a multimethod geological dating strategy. We found they were much younger than previously suggested, with some remains dating to the Holocene owing to the complex depositional history at these subtropical caves. Current evidence shows AMHs settled southern China within the timeframe set by molecular data of less than ca. 50 to 45 ka and no earlier. The expansion of anatomically modern humans (AMHs) from Africa around 65,000 to 45,000 y ago (ca. 65 to 45 ka) led to the establishment of present-day non-African populations. Some paleoanthropologists have argued that fossil discoveries from Huanglong, Zhiren, Luna, and Fuyan caves in southern China indicate one or more prior dispersals, perhaps as early as ca. 120 ka. We investigated the age of the human remains from three of these localities and two additional early AMH sites (Yangjiapo and Sanyou caves, Hubei) by combining ancient DNA (aDNA) analysis with a multimethod geological dating strategy. Although U\u2013Th dating of capping flowstones suggested they lie within the range ca. 168 to 70 ka, analyses of aDNA and direct AMS 14C dating on human teeth from Fuyan and Yangjiapo caves showed they derive from the Holocene. OSL dating of sediments and AMS 14C analysis of mammal teeth and charcoal also demonstrated major discrepancies from the flowstone ages; the difference between them being an order of magnitude or more at most of these localities. Our work highlights the surprisingly complex depositional history recorded at these subtropical caves which involved one or more episodes of erosion and redeposition or intrusion as recently as the late Holocene. In light of our findings, the first appearance datum for AMHs in southern China should probably lie within the timeframe set by molecular data of ca. 50 to 45 ka.", "keyphrases": ["modern human", "southern china", "cave", "ancient dna"]}
{"id": "10.1111/j.1558-5646.2011.01415.x", "title": "HOW DO GEOLOGICAL SAMPLING BIASES AFFECT STUDIES OF MORPHOLOGICAL EVOLUTION IN DEEP TIME? A CASE STUDY OF PTEROSAUR (REPTILIA: ARCHOSAURIA) DISPARITY", "abstract": "A fundamental contribution of paleobiology to macroevolutionary theory has been the illumination of deep time patterns of diversification. However, recent work has suggested that taxonomic diversity counts taken from the fossil record may be strongly biased by uneven spatiotemporal sampling. Although morphological diversity (disparity) is also frequently used to examine evolutionary radiations, no empirical work has yet addressed how disparity might be affected by uneven fossil record sampling. Here, we use pterosaurs (Mesozoic flying reptiles) as an exemplar group to address this problem. We calculate multiple disparity metrics based upon a comprehensive anatomical dataset including a novel phylogenetic correction for missing data, statistically compare these metrics to four geological sampling proxies, and use multiple regression modeling to assess the importance of uneven sampling and exceptional fossil deposits (Lagerst\u00e4tten). We find that range\u2010based disparity metrics are strongly affected by uneven fossil record sampling, and should therefore be interpreted cautiously. The robustness of variance\u2010based metrics to sample size and geological sampling suggests that they can be more confidently interpreted as reflecting true biological signals. In addition, our results highlight the problem of high levels of missing data for disparity analyses, indicating a pressing need for more theoretical and empirical work.", "keyphrases": ["sampling", "pterosaur", "disparity metric", "phylogenetic correction"]}
{"id": "10.1080/02724634.1994.10011524", "title": "The pectoral girdle and forelimb of the basal theropod Herrerasaurus ischigualastensis", "abstract": "ABSTRACT New specimens of Herrerasaurus ischigualastensis shed light on the structure and function of the pectoral girdle and forelimb in early theropod dinosaurs. As in tetanurian theropods, the scapulocoracoid has a broadly expanded acromion and strap-shaped scapular blade. The forelimb is less than one-half the length of the hind-limb and is specialized for prey capture and manipulation. The short proximal segments of the forelimb provide mechanical advantage and are marked by prominent tuberosities. The well-ossified carpus is divided into two functional units, one composed of the radiale and ulnare and the other composed of a centrale and distal carpals, and is designed functionally for dorsoventral extension and flexion of the manus against the forearm. The manus is longer than the humerus, radius, or ulna and is specialized for grasping and raking, as shown by the marked metacarpal extensor depressions, long penultimate phalanges, and trenchant unguals in digits I\u2013III. Upon flexion or extension, th...", "keyphrases": ["pectoral girdle", "forelimb", "herrerasaurus ischigualastensis"]}
{"id": "paleo.009690", "title": "Tooth morphology elucidates shark evolution across the end-Cretaceous mass extinction", "abstract": "Sharks (Selachimorpha) are iconic marine predators that have survived multiple mass extinctions over geologic time. Their prolific fossil record is represented mainly by isolated shed teeth, which provide the basis for reconstructing deep time diversity changes affecting different selachimorph clades. By contrast, corresponding shifts in shark ecology, as measured through morphological disparity, have received comparatively limited analytical attention. Here, we use a geometric morphometric approach to comprehensively examine tooth morphologies in multiple shark lineages traversing the catastrophic end-Cretaceous mass extinction\u2014this event terminated the Mesozoic Era 66 million years ago. Our results show that selachimorphs maintained virtually static levels of dental disparity in most of their constituent clades across the Cretaceous\u2013Paleogene interval. Nevertheless, selective extinctions did impact apex predator species characterized by triangular blade-like teeth. This is particularly evident among lamniforms, which included the dominant Cretaceous anacoracids. Conversely, other groups, such as carcharhiniforms and orectolobiforms, experienced disparity modifications, while heterodontiforms, hexanchiforms, squaliforms, squatiniforms, and \u2020synechodontiforms were not overtly affected. Finally, while some lamniform lineages disappeared, others underwent postextinction disparity increases, especially odontaspidids, which are typified by narrow-cusped teeth adapted for feeding on fishes. Notably, this increase coincides with the early Paleogene radiation of teleosts as a possible prey source, and the geographic relocation of disparity sampling \u201chotspots,\u201d perhaps indicating a regionally disjunct extinction recovery. Ultimately, our study reveals a complex morphological response to the end-Cretaceous mass extinction and highlights an event that influenced the evolution of modern sharks.", "keyphrases": ["shark", "end-cretaceous mass extinction", "tooth morphology"]}
{"id": "10.1111/gbi.12378", "title": "Free and kerogen\u2010bound biomarkers from late Tonian sedimentary rocks record abundant eukaryotes in mid\u2010Neoproterozoic marine communities", "abstract": "Lipid biomarker assemblages preserved within the bitumen and kerogen phases of sedimentary rocks from the ca. 780\u2013729 Ma Chuar and Visings\u00f6 Groups facilitate paleoenvironmental reconstructions and reveal fundamental aspects of emerging mid\u2010Neoproterozoic marine communities. The Chuar and Visings\u00f6 Groups were deposited offshore of two distinct paleocontinents (Laurentia and Baltica, respectively) during the Tonian Period, and the rock samples used had not undergone excessive metamorphism. The major polycyclic alkane biomarkers detected in the rock bitumens and kerogen hydropyrolysates consist of tricyclic terpanes, hopanes, methylhopanes, and steranes. Major features of the biomarker assemblages include detectable and significant contribution from eukaryotes, encompassing the first robust occurrences of kerogen\u2010bound regular steranes from Tonian rocks, including 21\u2010norcholestane, 27\u2010norcholestane, cholestane, ergostane, and cryostane, along with a novel unidentified C30 sterane series from our least thermally mature Chuar Group samples. Appreciable values for the sterane/hopane (S/H) ratio are found for both the free and kerogen\u2010bound biomarker pools for both the Chuar Group rocks (S/H between 0.09 and 1.26) and the Visings\u00f6 Group samples (S/H between 0.03 and 0.37). The more organic\u2010rich rock samples generally yield higher S/H ratios than for organic\u2010lean substrates, which suggests a marine nutrient control on eukaryotic abundance relative to bacteria. A C27 sterane (cholestane) predominance among total C26\u2013C30 steranes is a common feature found for all samples investigated, with lower amounts of C28 steranes (ergostane and crysotane) also present. No traces of known ancient C30 sterane compounds; including 24\u2010isopropylcholestanes, 24\u2010n\u2010propylcholestanes, or 26\u2010methylstigmastanes, are detectable in any of these pre\u2010Sturtian rocks. These biomarker characteristics support the view that the Tonian Period was a key interval in the history of life on our planet since it marked the transition from a bacterially dominated marine biosphere to an ocean system which became progressively enriched with eukaryotes. The eukaryotic source organisms likely encompassed photosynthetic primary producers, marking a rise in red algae, and consumers in a revamped trophic structure predating the Sturtian glaciation.", "keyphrases": ["sedimentary rock", "eukaryote", "mid\u2010neoproterozoic marine community", "tonian period"]}
{"id": "10.1029/2002PA000873", "title": "Nonuniform response of the major surface currents in the Nordic Seas to insolation forcing: Implications for the Holocene climate variability", "abstract": "[1]\u00a0High-resolution sediment cores from the Voring Plateau, the North Iceland shelf, and the East Greenland shelf have been studied to investigate the stability of major surface currents in the Nordic Seas during the Holocene. Results from diatom assemblages and reconstructed sea-surface temperatures (SSTs) indicate a division of the Holocene into three periods: the Holocene Climate Optimum (9500\u20136500 calendar (cal) years BP), the Holocene Transition Period (6500\u20133000 cal years BP) and the Cool Late Holocene Period (3000\u20130 cal years BP). The overall climate development is in step with the decreasing insolation on the Northern Hemisphere, but regional differences occur regarding both timing and magnitude of SST changes. Sites under the direct influence of the Norwegian Atlantic Current and the Irminger Current indicate SST cooling of 4\u20135\u00b0C from early Holocene to present, compared to 2\u00b0C recorded under the East Greenland Current. Superimposed on the general Holocene cooling trend, there is a high-frequency SST variability, which is in the order of 1\u20131.5\u00b0C for the Voring Plateau and the East Greenland shelf and 2.5\u20133\u00b0C on the North Iceland shelf.", "keyphrases": ["major surface current", "nordic seas", "insolation"]}
{"id": "paleo.004925", "title": "Discriminating signal from noise in the fossil record of early vertebrates reveals cryptic evolutionary history", "abstract": "The fossil record of early vertebrates has been influential in elucidating the evolutionary assembly of the gnathostome bodyplan. Understanding of the timing and tempo of vertebrate innovations remains, however, mired in a literal reading of the fossil record. Early jawless vertebrates (ostracoderms) exhibit restriction to shallow-water environments. The distribution of their stratigraphic occurrences therefore reflects not only flux in diversity, but also secular variation in facies representation of the rock record. Using stratigraphic, phylogenetic and palaeoenvironmental data, we assessed the veracity of the fossil records of the jawless relatives of jawed vertebrates (Osteostraci, Galeaspida, Thelodonti, Heterostraci). Non-random models of fossil recovery potential using Palaeozoic sea-level changes were used to calculate confidence intervals of clade origins. These intervals extend the timescale for possible origins into the Upper Ordovician; these estimates ameliorate the long ghost lineages inferred for Osteostraci, Galeaspida and Heterostraci, given their known stratigraphic occurrences and stem\u2013gnathostome phylogeny. Diversity changes through the Silurian and Devonian were found to lie within the expected limits predicted from estimates of fossil record quality indicating that it is geological, rather than biological factors, that are responsible for shifts in diversity. Environmental restriction also appears to belie ostracoderm extinction and demise rather than competition with jawed vertebrates.", "keyphrases": ["early vertebrate", "ostracoderm", "silurian"]}
{"id": "10.1093/zoolinnean/zlz106", "title": "Late Cretaceous (Maastrichtian) crocodyliforms from north-eastern Iberia: a first attempt to explain the crocodyliform diversity based on tooth qualitative traits", "abstract": "\n During recent years, knowledge about crocodyliform diversity of the uppermost Cretaceous from Europe has been substantially improved. Palaeontological efforts have also been focused on microvertebrate diversity and its palaeoecological implications. Isolated crocodylomorph teeth are, by far, one of the most frequently recovered elements in microvertebrate samples. In the present paper, morphological features of crocodylomorph teeth collected throughout the complete Maastrichtian series of the southern Pyrenean basin (north-eastern Spain), together with several mandibular remains, are described and analysed. Teeth were grouped in morphotypes and their taxonomic significance is discussed. The results highlight a diverse crocodylomorph assemblage in this area throughout the Maastrichtian. In addition, feeding habits and environmental preferences are inferred for the identified taxa according to dental features, occurrences and taphonomy.", "keyphrases": ["maastrichtian", "crocodyliform diversity", "tooth"]}
{"id": "10.1080/14772019.2016.1191045", "title": "A new eomysticetid from the Oligocene Kokoamu Greensand of New Zealand and a review of the Eomysticetidae (Mammalia, Cetacea)", "abstract": "Eomysticetids represent a worldwide, short-lived radiation of archaic baleen-bearing mysticetes that elucidate morphofunctional shifts and ontogenetic change amongst early Neoceti. Fossils of eomysticetids are now recorded from Oligocene marine rocks along the margins of the North Pacific (Japan), North Atlantic (South Carolina), and the Southern Ocean (New Zealand). The assemblage from New Zealand is diverse, with five species in three genera present during the Duntroonian stage (Chattian, 27.3\u201325.2 Ma). A new genus and species of eomysticetid from the lower Kokoamu Greensand of New Zealand, Matapa waihao gen. et sp. nov., increases the known diversity of Southern Hemisphere eomysticetids. Matapa uniquely exhibits a rounded margin of the occipital shield, and shares a mosaic of features seen in Northern Hemisphere eomysticetids such as a large squamosal prominence, an inflated and posteriorly rounded paroccipital process, and a double-faced posterior bullar facet with longitudinal ridges. The holotype specimen of Matapa waihao is ontogenetically immature, but ontogenetically static tympanoperiotic characters that diagnose this new species are shared by referred adult specimens. Matapa is uppermost Whaingaroan (28.1\u201327.3 Ma) in age, the oldest eomysticetid from New Zealand. Fossils of Matapa are recovered from both the modern west and east coast of New Zealand which, during the Oligocene, were on the margin of the Southern Ocean. Inclusion of Matapa within an earlier published cladistic analysis recovers Matapa as the earliest diverging member of the New Zealand eomysticetid clade, and confirms eomysticetid monophyly. The taxonomy, morphology and geochronological age of all known eomysticetids are reviewed. http://zoobank.org/urn:lsid:zoobank.org:pub:EE1CB5CC-618B-4ABA-9D97-5B9DEDD3470E", "keyphrases": ["eomysticetid", "oligocene", "new zealand"]}
{"id": "10.1130/g31145.1", "title": "Iodine to calcium ratios in marine carbonate as a paleo-redox proxy during oceanic anoxic events", "abstract": "Periods of globally distributed extreme oxygen depletion, so-called oceanic anoxic events (OAEs), have been recognized in the Mesozoic geological record and appear to be characteristic of episodes of extreme warmth. Here we explore the application of iodine/calcium ratios (I/Ca) in marine carbonate as a new geochemical proxy to constrain seawater redox change, and provide additional insights into the response of ocean chemistry to ancient climatic warming. Iodine has long been known as a redox-sensitive and biophilic element, mainly present as iodate and iodide in seawater, iodate converting to iodide under anoxic conditions. Laboratory experiments growing calcite crystals from solutions spiked with iodate show that this is the ionic species incorporated into the carbonate structure, likely substituting for the CO 3 2\u2212 ion. A fall in the I/Ca ratio measured in carbonates formed in shallow water by marine calcifiers during the early Toarcian and Cenomanian-Turonian OAEs is interpreted both as a response to a decrease in the iodate/iodide ratio in ocean waters and the drawdown of the global iodine inventory under conditions of accelerated organic-matter burial. The results suggest that I/Ca ratios in carbonates may be used to monitor seawater oxidation levels throughout Earth history.", "keyphrases": ["calcium ratio", "marine carbonate", "oceanic anoxic event", "iodine"]}
{"id": "10.1080/02724634.2016.1212059", "title": "Tarsals of Sespedectinae (?Lipotyphla) from the Middle Eocene of Southern California, and the Affinities of Eocene \u2018Erinaceomorphs\u2019", "abstract": "ABSTRACT Postcranial morphology of Paleogene lipotyphlans (Mammalia: Laurasiatheria) is poorly known relative to dental morphology. When these elements can be referred, they have proven to be a rich source of data for phylogenetic and ecological inferences. In particular, tarsal morphology has challenged hypothesized relationships of several taxa. We refer isolated tarsals from several early and late Uintan (middle Eocene) localities in the San Diego area to three genera of sespedectine erinaceomorph lipotyphlan, Crypholestes, Proterixoides, and Sespedectes, based on patterns of size, morphology, and abundance. Astragali and calcanei are confidently referred to all three genera, whereas naviculars are more tentatively referred to Proterixoides and Sespedectes, and cuboids to Sespedectes. Tarsals of the three genera are morphologically nearly uniform, supporting their hypothesized close relationship. The most significant difference is a relatively longer calcaneal tuber in Proterixoides. The tarsal morphology of Sespedectinae is most consistent with an unspecialized terrestrial locomotor repertoire. Some distinctive features of the sespedectine tarsus, such as \u2018S\u2019-shaped ectal facets and a prominent tuber tibialis on the navicular, are potentially indicative of lipotyphlan affinities. However, there is no support for an exclusive relationship to extant erinaceids (or any other lipotyphlan family) or to other Paleogene erinaceomorphs (Macrocranion, Zionodon). Phylogenetic analysis confirms that sespedectines are most likely relatively basal lipotyphlans and that Erinaceomorpha is not a natural group.", "keyphrases": ["sespedectinae", "middle eocene", "tarsal"]}
{"id": "paleo.001498", "title": "HIGHLY DIVERSIFIED LATE CRETACEOUS FISH ASSEMBLAGE REVEALED BY OTOLITHS (RIPLEY FORMATION AND OWL CREEK FORMATION, NORTHEAST MISSISSIPPI, USA)", "abstract": "Bulk sampling and extensive, systematic surface collecting of the Coon Creek Member of the Ripley Formation (early Maastrichtian) at the Blue Springs locality and primarily bulk sampling of the Owl Creek Formation (late Maastrichtian) at the Owl Creek type locality, both in northeast Mississippi, USA, have produced the largest and most highly diversified actinopterygian otolith (ear stone) assemblage described from the Mesozoic of North America. The 3,802 otoliths represent 30 taxa of bony fishes representing at least 22 families. In addition, there were two different morphological types of lapilli, which were not identifiable to species level. The large number of otolith specimens as well as the preservation contributed to the recognition of 4 new genera and 13 new species. The otoliths supplied information regarding the presence of bony fishes not available solely on the basis of osteological remains, and the Late Cretaceous bony fish assemblage at the sites would be underestimated and misinterpreted without an examination of the otoliths. The otoliths also contributed evidence on the evolutionary development of teleosts in North America, especially the diversity of the beryciforms in the Late Cretaceous, and provided indications of the paleoecology during the Maastrichtian. The Ripley Formation (Coon Creek Member) otolith assemblage, which accounted for 3,718 of the specimens, is compared to other Cretaceous otolith assemblages in North America that meet certain criteria (employed bulk-sampling techniques, had well-preserved specimens, and possessed a substantial number of specimens and taxa for analysis). These sites were in Alabama, Maryland, Mississippi (two localities), New Jersey, North Carolina, North Dakota, Tennessee, and Texas. Systematic surface collecting at the Blue Springs locality proved to be very beneficial in supplying otoliths specimens from maturer fishes. Many of the surface-collected otoliths represent older adult fishes that assist with the identification of several forms with greater specificity.", "keyphrases": ["otolith", "ripley formation", "owl creek formation", "north america", "cretaceous otolith assemblage"]}
{"id": "10.1002/spp2.1258", "title": "Gastropods from the Jurassic neptunian sills of Rocca Busambra (north\u2010western Sicily, Italy): Patellogastropoda, Pleurotomarioidea, Scissurelloidea, Fissurelloidea and Eucycloidea", "abstract": "The gastropods from Jurassic neptunian sills of Rocca Busambra (Sicily, Italy) represent an extraordinary assemblage for richness and extremely high degree of novelty, consisting of about 250 species (two\u2010thirds of which are new) of 20 superfamilies. A total of 38 species and 18 genera of Lottioidea, Pleurotomarioidea, Scissurelloidea, Fissurelloidea and Eucycloidea are described. Of these, 30 species and 9 genera are new, namely Ramusatomaria nuda gen. et sp. nov., Trapanimaria gattoi gen. et sp. nov., Trapanimaria nicolosiensis gen. et sp. nov., Trapanimaria? pallinii gen. et sp. nov., Trochotomaria conoidea sp. nov., Trochotomaria polymorpha sp. nov., Laevitomaria babalusciae sp. nov., Pyrgotrochus vorosi sp. nov., Auritoma lenticula gen. et sp. nov., Busambrella fasciata gen. et sp. nov., Emarginula (Emarginula) burgioi sp. nov., Emarginula (Tauschia) acutidens sp. nov., Propeucyclus sicanus gen. et sp. nov., Propeucyclus obesus gen. et sp. nov., Propeucyclus? semireticulatus gen. et sp. nov., Eucyclomphalus? marenostrum sp. nov., Toronyella lineata gen. et sp. nov., Toronyella margaritata gen. et sp. nov., Zarnglaffia polygonalis sp. nov., Zarnglaffia palermitana sp. nov., Ambercyclus cratisculptus sp. nov., Elymicyclus alternatus gen. et sp. nov., Elymicyclus ietumensis gen. et sp. nov., Elymicyclus martae gen. et sp. nov., Elymicyclus garibaldii gen. et sp. nov., Jurassiscala sturanii gen. et sp. nov., Jurassiscala? tenuiretis gen. et sp. nov., Fischeriella sicula sp. nov., Retimusina poseidoni gen. et sp. nov. and Retimusina? tritoni sp. nov. The new scissurelloidean family Auritomidae fam. nov. is erected. A palaeobiogeographical analysis indicates close relationships with coeval faunas from condensed pelagic carbonates of the central region of western Tethys.", "keyphrases": ["scissurelloidea", "eucycloidea", "gastropod"]}
{"id": "paleo.002036", "title": "A new species of Azendohsaurus (Diapsida: Archosauromorpha) from the Triassic Isalo Group of southwestern Madagascar: cranium and mandible", "abstract": "Abstract:\u2002 Here, we describe a new species of Azendohsaurus from the Middle\u2013Late Triassic of Madagascar, extending the geographical range of a taxon known otherwise only by a single species from Morocco. Although Azendohsaurus has consistently been regarded as an early dinosaur (based on various advanced dental and gnathic features resembling those characterizing certain dinosaur subgroups), the relatively complete skeletal material, now available from Madagascar, argues strongly against its dinosaurian affinities. Rather, the retention of numerous primitive cranial and postcranial features indicates a surprisingly early divergence of Azendohsaurus within Archosauromorpha and an unusual mosaic of characters in this taxon. Features considered diagnostic of Sauropodomorpha thus are inferred to occur homoplastically in at least one clade of nondinosaurian archosauromorphs, indicating a complex evolution and distribution of features traditionally thought to be derived within archosaurs. Azendohsaurus has teeth resembling those of both early sauropodomorph and ornithischian dinosaurs, yet also possesses numerous inarguable basal archosauromorph cranial and postcranial attributes. This highlights the risk of uncritically referring isolated, Middle\u2013Late Triassic (or even later), \u2018leaf\u2010shaped\u2019 teeth with denticles to the Dinosauria. Similarly, the occurrence of such teeth in an early diverging archosauromorph indicates that specializations for herbivory originated more frequently within this clade than conventionally assumed. For example, Azendohsaurus and numerous basal sauropodomorph dinosaur taxa share an array of convergently acquired features associated with herbivory, including tooth denticles, expanded tooth crowns, a downturned dentary and the articular located at the ventral margin of the mandible. Some of these features (denticles, expanded crowns and the ventrally deflected articular) are even more widespread among archosauromorphs, including aetosaurs, silesaurs and ornithischian dinosaurs. A downturned dentary also occurs in Trilophosaurus, a taxon further marked by unique specializations for herbivory, including transversely lophate, tricuspid teeth. An array of features associated with herbivory also occurs in rhynchosaurs and certain crocodilians (e.g. Simosuchus). This distribution suggests that craniodental features associated with herbivory were much more pervasive across the archosauromorph clade than previously recognized, possibly evolving at least six to eight times independently.", "keyphrases": ["azendohsaurus", "archosauromorpha", "mandible"]}
{"id": "paleo.000567", "title": "X-ray micro-tomography of Carboniferous stem-Dictyoptera: new insights into early insects", "abstract": "Computer reconstructions of Archimylacris eggintoni, a Carboniferous stem-group dictyopteran (\u2018roachoid\u2019), are presented. A siderite-hosted specimen was scanned using high-resolution X-ray microtomography (\u00b5CT), and a \u2018virtual fossil\u2019 was created with a resolution of 17.7 \u00b5m. This has revealed the morphology in great detail, including adhesive limb structures indicative of climbing and specializations for rapid movement. The antennae are filiform, and the mandibles are comparable to those of certain extant cockroaches, suggesting a similar generalist, saprophagous diet. The reconstruction reveals a high degree of specialization, and provides insights into the mode of life of these common Palaeozoic insects. Further \u00b5CT study of insect fossils has the potential to supplement wing venation with new characters, and hence improve fossil insect phylogenies.", "keyphrases": ["insect", "x-ray micro-tomography", "coal measures fossil", "powerful tool"]}
{"id": "paleo.003962", "title": "Squatiniformes (Chondrichthyes, Neoselachii) from the Late Cretaceous of southern England and northern France with redescription of the holotype of Squatina cranei Woodward, 1888", "abstract": "Abstract:\u2002 Bulk sampling of phosphate\u2010rich horizons within the Late Cretaceous of the Anglo\u2010Paris Basin yielded numerous teeth of members of the Squatiniformes. Along with isolated tooth remains, two museum specimens comprising partial articulated encoskeletal remains including the holotype of the species Squatina cranei Woodward, 1888a are described, and a new subgenus Cretascyllium is proposed for species of the genus Squatina with high degree of heterodonty and triangular anterior teeth. The species Squatina (Cretascyllium) cranei comb. nov. and Squatina (Cretascyllium) hassei comb. nov. are referred to this subgenus. The genus Parasquatina Herman, 1982 previously erected on a single tooth is valid, and two new species P. justinensis sp. nov. and P. jarvisi sp. nov. are described along with a third taxon Parasquatina sp. An enigmatic tooth referred to ?Neoselachii incertae sedis is also reported. The palaeoecology of these taxa is discussed.", "keyphrases": ["late cretaceous", "holotype", "squatiniformes"]}
{"id": "10.7717/peerj.10101", "title": "The osteology and phylogenetic position of the loricatan (Archosauria: Pseudosuchia) Heptasuchus clarki, from the ?Mid-Upper Triassic, southeastern Big Horn Mountains, Central Wyoming (USA)", "abstract": "Loricatan pseudosuchians (known as \u201crauisuchians\u201d) typically consist of poorly understood fragmentary remains known worldwide from the Middle Triassic to the end of the Triassic Period. Renewed interest and the discovery of more complete specimens recently revolutionized our understanding of the relationships of archosaurs, the origin of Crocodylomorpha, and the paleobiology of these animals. However, there are still few loricatans known from the Middle to early portion of the Late Triassic and the forms that occur during this time are largely known from southern Pangea or Europe. Heptasuchus clarki was the first formally recognized North American \u201crauisuchian\u201d and was collected from a poorly sampled and disparately fossiliferous sequence of Triassic strata in North America. Exposed along the trend of the Casper Arch flanking the southeastern Big Horn Mountains, the type locality of Heptasuchus clarki occurs within a sequence of red beds above the Alcova Limestone and Crow Mountain formations within the Chugwater Group. The age of the type locality is poorly constrained to the Middle\u2014early Late Triassic and is likely similar to or just older than that of the Popo Agie Formation assemblage from the western portion of Wyoming. The holotype consists of associated cranial elements found in situ, and the referred specimens consist of crania and postcrania. Thus, about 30% of the osteology of the taxon is preserved. All of the pseudosuchian elements collected at the locality appear to belong to Heptasuchus clarki and the taxon is not a chimera as previously hypothesized. Heptasuchus clarki is distinct from all other archosaurs by the presence of large, posteriorly directed flanges on the parabasisphenoid and a distinct, orbit-overhanging postfrontal. Our phylogenetic hypothesis posits a sister-taxon relationship between Heptasuchus clarki and the Ladinian-aged Batrachotomus kupferzellensis from current-day Germany within Loricata. These two taxa share a number of apomorphies from across the skull and their phylogenetic position further supports \u2018rauisuchian\u2019 paraphyly. A minimum of three individuals of Heptasuchus are present at the type locality suggesting that a group of individuals died together, similar to other aggregations of loricatans (e.g., Heptasuchus, Batrachotomus, Decuriasuchus, Postosuchus).", "keyphrases": ["osteology", "phylogenetic position", "big horn mountains"]}
{"id": "paleo.005112", "title": "Cutting the first \u2018teeth\u2019: a new approach to functional analysis of conodont elements", "abstract": "The morphological disparity of conodont elements rivals the dentition of all other vertebrates, yet relatively little is known about their functional diversity. Nevertheless, conodonts are an invaluable resource for testing the generality of functional principles derived from vertebrate teeth, and for exploring convergence in a range of food-processing structures. In a few derived conodont taxa, occlusal patterns have been used to derive functional models. However, conodont elements commonly and primitively exhibit comparatively simple coniform morphologies, functional analysis of which has not progressed much beyond speculation based on analogy. We have generated high-resolution tomographic data for each morphotype of the coniform conodont Panderodus acostatus. Using virtual cross sections, it has been possible to characterize changes in physical properties associated with individual element morphology. Subtle changes in cross-sectional profile have profound implications for the functional performance of individual elements and the apparatus as a whole. This study has implications beyond the ecology of a single conodont taxon. It provides a basis for reinterpreting coniform conodont taxonomy (which is based heavily on cross-sectional profiles), in terms of functional performance and ecology, shedding new light on the conodont fossil record. This technique can also be applied to more derived conodont morphologies, as well as analogous dentitions in other vertebrates and invertebrates.", "keyphrases": ["functional analysis", "conodont element", "vertebrate", "tooth"]}
{"id": "10.4081/jlimnol.2013.s2.e1", "title": "The palaeogeography of Sundaland and Wallacea since the Late Jurassic", "abstract": "The continental core of Southeast (SE) Asia, Sundaland, was assembled from Gondwana fragments by the Early Mesozoic. Continental blocks rifted from Australia in the Jurassic [South West (SW) Borneo, East Java-West Sulawesi-Sumba], and the Woyla intraoceanic arc of Sumatra, were added to Sundaland in the Cretaceous. These fragments probably included emergent areas and could have carried a terrestrial flora and fauna. Sarawak, the offshore Luconia-Dangerous Grounds areas, and Palawan include Asian continental material. These probably represent a wide accretionary zone at the Asia-Pacific boundary, which was an active continental margin until the mid Cretaceous. Subduction ceased around Sundaland in the Late Cretaceous, and from about 80 Ma most of Sundaland was emergent, physically connected to Asia, but separated by deep oceans from India and Australia. India moved rapidly north during the Late Cretaceous and Early Cenozoic but there is no evidence that it made contact with SE Asia prior to collision with Asia. One or more arc-India collisions during the Eocene may have preceded India-Asia collision. The arcs could have provided dispersal pathways from India into SE Asia before final suturing of the two continents. During the Late Cretaceous and Early Cenozoic there was no significant subduction beneath Sumatra, Java and Borneo. At about 45 Ma Australia began to move north, subduction resumed and there was widespread rifting within Sundaland. During the Paleogene east and north Borneo were largely submerged, the Makassar Straits became a wide marine barrier within Sundaland, and West Sulawesi was separated from Sundaland but included land. By the Early Miocene the proto-South China Sea had been eliminated by subduction leading to emergence of land in central Borneo, Sabah and Palawan. Australia-SE Asia collision began, eliminating the former deep ocean separating the two continents, and forming the region now known as Wallacea. The microplate or terrane concept of slicing fragments from New Guinea followed by multiple collisions in Wallacea is implausible. Neogene subduction drove extension and fragmentation of Wallacea that caused both subsidence of deep marine basins and elevation of land;\u00a0bathymetry changed very rapidly, especially during the Pliocene, but the detailed palaeogeography of this region remains uncertain.", "keyphrases": ["palaeogeography", "sundaland", "wallacea", "emergence"]}
{"id": "paleo.011427", "title": "Leishmaniasis in Ancient Egypt and Upper Nubia", "abstract": "To the Editor: Leishmaniasis is a disease caused by parasites of the genus Leishmania. The infection is transmitted to humans through the bites of female sandflies and manifests mainly in 3 forms: visceral, cutaneous, and mucocutaneous. Visceral leishmaniasis or kala-azar, the often fatal form of the disease, is caused by species of the Leishmania donovani complex. These parasites were responsible for severe recent outbreaks in Sudan and other countries and are thought to originate in East Africa (1\u20134). \n \nIn this report, we describe the successful amplification of L. donovani DNA in ancient Egyptian and Christian Nubian mummies dating back 4,000 years. Besides the first proof for visceral leishmaniasis in paleopathology, we provide evidence that leishmaniasis was present in Nubia in the early Christian period and that the organism also infected ancient Egyptians, probably because of close trading contacts to Nubia, during the Middle Kingdom. We analyzed 91 bone tissue samples from ancient Egyptian mummies and skeletons and 70 bone marrow samples from naturally mummified human remains from Upper Nubia. The Egyptian material derived from the Pre- to Early Dynastic site of Abydos (n = 7; 3500\u20132800 BC), a Middle Kingdom tomb in Thebes West (42; 2050\u20131650 BC), and different tomb complexes in Thebes West, which were built and used between the Middle and New Kingdom until the Late Period (42; c. 2050\u2013500 BC). The Nubian samples were taken before the flooding caused by the Aswan Dam from 2 early Christian burial sites at Kulubnarti, between the second and third cataracts of the Nile River in northern Sudan. One site was on an island in the Nile and dated from 550 to 750 AD. The other was on the western bank of the Nile and was in use from c.750 to 1500 AD. All samples were tested for Leishmania spp. DNA and further characterized by direct sequencing. \n \nIn 4 of the 91 Egyptian and 9 of the 70 Nubian samples, a 120-bp fragment of a conserved region of the minicircle molecule of kinetoplastid mitochondrial DNA of the parasite (5,6) could be successfully amplified and, with the first primer pair, unambiguously related to L. donovani species after sequencing (Figure). The positive samples from ancient Egypt exclusively originated from the Middle Kingdom tomb, while no molecular evidence for ancient Leishmania DNA was found in the Pre- to Early Dynastic and the New Kingdom to Late Period specimens. \n \n \n \nFigure \n \nPCR amplification of a 120-bp fragment of kinetoplastid mitochondrial DNA of Leishmania spp. in Egyptian and Nubian mummies. Lane 1, 50-bp ladder lanes 2\u20138, mummy samples; lanes 9,10, extraction controls; lane 11, PCR controls. Lane 6 provides ... \n \n \n \nIn the Middle Kingdom, the Egyptians extended trade relationships and military expeditions to Nubia, the modern Sudan, with particular interest in the gold resources of the country and in obtaining slaves to serve as servants or soldiers in the pharaoh\u2019s army. Today, the Sudan is one of the highly endemic countries for visceral leishmaniasis or kala-azar, which is thought to have originated in East Africa and later spread to the Indian subcontinent and the New World (4). Therefore, the high incidence of Leishmania DNA in the Middle Kingdom samples (4 [9.5%] of 42) and the lack of findings in earlier or later time periods, may indicate that leishmaniasis was introduced into Egypt at this time. Leishmaniasis did not likely become endemic in the Egyptian Nile Valley because the disease is closely linked to its vector, the phlebotomine sandfly, and the distribution of Acacia-Balanites woodland (7). That ancient Egyptians became infected because of close trade contacts and associated travel with Nubia during the Middle Kingdom seems more plausible. The high frequency of Leishmania DNA\u2013positive samples in the Nubian mummies (12.9%) suggests that leishmaniasis was endemic in Nubia during the Early Christian period and, in light of the data on the ancient Egyptian mummies, probably already several thousand years before. Taken together, our results support the theory that Sudan could have been indeed the original focus of visceral leishmaniasis (4). \n \nOur study shows a completely new aspect of molecular paleopathology. The detection of ancient pathogen DNA is not only used to identify a certain disease and gain information on its frequency and evolutionary origin but also to trace back cultural contacts and their role in the transmission and spread of infectious diseases.", "keyphrases": ["ancient egypt", "upper nubia", "leishmaniasis"]}
{"id": "10.1080/02724634.2015.1031341", "title": "Polycotylus latipinnis Cope (Plesiosauria, Polycotylidae), a Nearly Complete Skeleton from the Niobrara Formation (Early Campanian) of Southwestern South Dakota", "abstract": "ABSTRACT \n A nearly complete skeleton of Polycotylus latipinnis (SDSM 23020) from the upper Niobrara Formation (early Campanian) of South Dakota (U.S.A) greatly improves information for this formerly poorly known taxon. Specimens SDSM 23020 and YPM 1125 (paratype P. latipinnis) exhibit numerous postcranial characters that distinguish Polycotylus, in particular presacral vertebral count, nature of chevron facets, unique ilia, and highly derived paddles including five epipodial ossifications and increased hyperphalangy. Greater vertebral and phalangeal counts of Polycotylus are accompanied by exceptional foreshortening; thus, the relative body and limb proportions are likely similar to less derived polycotylids, with fewer, more elongate vertebrae and phalanges. The complete skull, derived among polycotylids, has short temporal fenestrae, elongate frontals, exceptionally slender parasphenoid with prominent cultriform process, and exceptionally long extensions of the angulars and splenials within the mandibular symphysis. Cladistic analysis indicates that Polycotylus nests firmly within derived Polycotylidae as a potential sister taxon to Dolichorhynchops osborni and Trinacromerum, despite a \u2018primitive\u2019 presacral vertebral count. Future improvements in available data, in particular better information regarding basal polycotylids, and refinement of character selection to nullify homoplasy could significantly alter the tree structure to show distinct subgroups within Polycotylidae. North American polycotylids with elongate temporal fenestrae, elongate podials, and relatively long vertebrae are confined to occurrences of late Cenomanian and earliest Turonian age, whereas polycotylids distinctly foreshortened in these respects are restricted to post-Turonian occurrences. Ilium morphology is highly variable among polycotylids and, in addition to taxonomic utility, may be in part attributable to sexual dimorphism.", "keyphrases": ["polycotylidae", "complete skeleton", "early campanian"]}
{"id": "10.2478/geoca-2014-0026", "title": "The systematics and paleobiogeographic significance of Sub-Boreal and Boreal ammonites (Aulacostephanidae and Cardioceratidae) from the Upper Jurassic of the Bohemian Massif", "abstract": "Abstract Upper Jurassic marine deposits are either rarely preserved due to erosion or buried under younger sediments in the Bohemian Massif. However, fossil assemblages from a few successions exposed in northern Bohemia and Saxony and preserved in museum collections document the regional composition of macro-invertebrate assemblages and thus provide unique insights into broad-scale distribution and migration pathways of ammonites during the Late Jurassic. In this paper, we focus on the systematic revision of ammonites from the Upper Oxfordian and Lower Kimmeridgian deposits of northern Bohemia and Saxony. The ammonites belong to two families (Aulacostephanidae and Cardioceratidae) of high paleobiogeographic and stratigraphic significance. Six genera belong to the family Aulacostephanidae (Prorasenia, Rasenia, Eurasenia, Rasenioides, Aulacostephanus, Aulacostephanoides) and one genus belongs to the family Cardioceratidae (Amoeboceras). They show that the Upper Jurassic deposits of the northern Bohemian Massif belong to the Upper Oxfordian and Lower Kimmeridgian and paleobiogeographically correspond to the German-Polish ammonite branch with the geographical extent from the Polish Jura Chain to the Swabian and Franconian Alb. Therefore, the occurrences of ammonites described here imply that migration pathway connecting the Polish Jura Chain with habitats in southern Germany was located during the Late Oxfordian and Early Kimmeridgian in the Bohemian Massif.", "keyphrases": ["ammonite", "aulacostephanidae", "cardioceratidae"]}
{"id": "paleo.009639", "title": "Resolving the relationships of Paleocene placental mammals", "abstract": "The \u2018Age of Mammals\u2019 began in the Paleocene epoch, the 10 million year interval immediately following the Cretaceous\u2013Palaeogene mass extinction. The apparently rapid shift in mammalian ecomorphs from small, largely insectivorous forms to many small\u2010to\u2010large\u2010bodied, diverse taxa has driven a hypothesis that the end\u2010Cretaceous heralded an adaptive radiation in placental mammal evolution. However, the affinities of most Paleocene mammals have remained unresolved, despite significant advances in understanding the relationships of the extant orders, hindering efforts to reconstruct robustly the origin and early evolution of placental mammals. Here we present the largest cladistic analysis of Paleocene placentals to date, from a data matrix including 177 taxa (130 of which are Palaeogene) and 680 morphological characters. We improve the resolution of the relationships of several enigmatic Paleocene clades, including families of \u2018condylarths\u2019. Protungulatum is resolved as a stem eutherian, meaning that no crown\u2010placental mammal unambiguously pre\u2010dates the Cretaceous\u2013Palaeogene boundary. Our results support an Atlantogenata\u2013Boreoeutheria split at the root of crown Placentalia, the presence of phenacodontids as closest relatives of Perissodactyla, the validity of Euungulata, and the placement of Arctocyonidae close to Carnivora. Periptychidae and Pantodonta are resolved as sister taxa, Leptictida and Cimolestidae are found to be stem eutherians, and Hyopsodontidae is highly polyphyletic. The inclusion of Paleocene taxa in a placental phylogeny alters interpretations of relationships and key events in mammalian evolutionary history. Paleocene mammals are an essential source of data for understanding fully the biotic dynamics associated with the end\u2010Cretaceous mass extinction. The relationships presented here mark a critical first step towards accurate reconstruction of this important interval in the evolution of the modern fauna.", "keyphrases": ["paleocene", "placental mammal", "protungulatum", "hyopsodontidae", "phylogenetic analysis"]}
{"id": "paleo.006226", "title": "A new hurdiid radiodont from the Burgess Shale evinces the exploitation of Cambrian infaunal food sources", "abstract": "Radiodonts, a clade of Cambro-Devonian stem group euarthropods, have classically been regarded as nektonic apex predators. However, many aspects of radiodont morphology and ecology have remained unclear because of the typically fragmentary nature of fossil material. Here, we describe a new hurdiid radiodont based on abundant and exceptionally well-preserved fossils from the Burgess Shale (Marble Canyon area, British Columbia, Canada). Cambroraster falcatus gen. et sp. nov. is characterized by an extra-large horseshoe-shaped head carapace, bearing conspicuous posterolateral spinous processes, and partially covering a short trunk with eight pairs of lateral flaps. Each of the pair of frontal appendages possess five mesially curving rake-like endites equipped with a series of anteriorly directed hooked spines, altogether surrounding the oral cone. This feeding apparatus suggests a micro to macrophagous sediment-sifting feeding ecology. Cambroraster illuminates the evolution of Hurdiidae and evinces the exploitation of the diversifying infauna by these large and specialized nektobenthic carnivores in the aftermath of the Cambrian explosion.", "keyphrases": ["new hurdiid radiodont", "burgess shale", "exploitation", "appendage", "rake-like endite"]}
{"id": "10.1002/2015GC006106", "title": "Alkenone paleothermometry in the North Atlantic: A review and synthesis of surface sediment data and calibrations", "abstract": "Despite a clear correlation of alkenone unsaturation and sea surface temperatures (SST) throughout most parts of the ocean, scatter of the regression for various calibration equations has been shown to increase significantly at low SSTs. In this study, we combine previously published (n\u2009=\u2009101) and new (n\u2009=\u200951) surface sediment data from the northern North Atlantic to constrain uncertainties of alkenone paleothermometry at low SSTs and to discuss possible sources of the increased scatter in the regression. The correlation between alkenone unsaturation and SSTs is strongest, in particular at the cold end (SSTs\u2009<\u200910\u00b0C), when the tetra\u2010unsaturated alkenones (C37:4) are included in the unsaturation index (expressed as U37K ) and regressed against spring\u2010summer temperature. Surface ocean salinity and sea ice cover are not correlated with U37K per se. However, samples located in regions of permanent winter sea ice cover exhibit a significant warm bias. Deviation from the linear regression is posited to be related to a number of additional non\u2010exclusive factors, such as advection of allochthonous material, local temperature stratification, and uncertainty in the absolute age of surface sediment samples assumed to be equivalent to modern conditions. We conclude that alkenone unsaturation allows accurate reconstruction of SST records from many regions of the North Atlantic if the factors confounding alkenone paleothermometry detailed here can be excluded.", "keyphrases": ["north atlantic", "surface sediment data", "sst", "alkenone paleothermometry"]}
{"id": "10.1088/2051-672X/4/2/023002", "title": "Dental microwear textures: reconstructing diets of fossil mammals", "abstract": "Dietary information of fossil mammals can be revealed via the analysis of tooth morphology, tooth wear, tooth geochemistry, and the microscopic wear patterns on tooth surfaces resulting from food processing. Although dental microwear has long been used by anthropologists and paleontologists to clarify diets in a diversity of mammals, until recently these methods focused on the counting of wear features (e.g., pits and scratches) from two-dimensional surfaces (typically via scanning electron microscopes or low-magnification light microscopes). The analysis of dental microwear textures can instead reveal dietary information in a broad range of herbivorous, omnivorous, and carnivorous mammals by characterizing microscopic tooth surfaces in three-dimensions, without the counting of individual surface features. To date, dental microwear textures in ungulates, xenarthrans, marsupials, carnivorans, and primates (including humans and their ancestors) are correlated with known dietary behavior in extant taxa and reconstruct ancient diets in a diversity of prehistoric mammals. For example, tough versus hard object feeding can be characterized across disparate phylogenetic groups and can distinguish grazers, folivorous, and flesh consumers (tougher food consumers) from woody browsers, frugivores, and bone consumers (harder object feeders). This paper reviews how dental microwear textures can be useful to reconstructing diets in a broad array of living and extinct mammals, with commentary on areas of future research.", "keyphrases": ["fossil mammal", "dental microwear texture", "dmta"]}
{"id": "paleo.002476", "title": "A Gondwanan perspective on the Ordovician Radiation constrains its temporal duration and suggests first wave of speciation, fuelled by Cambrian clades", "abstract": "This study presents a Cambrian\u2013Ordovician (Cambrian, \u2018Series 3\u2019 \u2013 Katian, Ka4) brachiopod \u03b1-diversity curve for the Iberian terrane. Three diversity pulses characterized the northern Gondwanan margin through the studied interval; an initial increase in linguliformean diversity that culminated during the Tremadocian (Tr3); a second, Darriwilian (Dw2) pulse caused primarily by a rise in orthid species; and a third pulse during Katian times (Ka3\u20134) marking the most diverse and phylogenetically complex faunas recorded in this study. Each of the three diversity pulses is phylogenetically distinct and characterized by large turnover rates. The first pulse consists almost exclusively of remnants of the Cambrian Evolutionary Fauna, whereas the second pulse shows a sudden rise of clades typical of the Paleozoic Evolutionary Fauna. The fact that otherwise typical Cambrian clades also radiated at the dawn of the Ordovician suggests that whatever facilitated the emerging Ordovician Radiation, also benefitted these ancient lineages. However, eventually the succeeding Paleozoic Evolutionary Fauna came to dominate during the second diversity pulse. This pulse represents a high-latitude correlative to the main pulse of the Ordovician Radiation. Although it coincides with a globally occurring transgression of eustatic nature, our analysis shows that the generic composition remained overwhelmingly endemic up through the Darriwilian\u2013Sandbian interval. Opposed to this, the third pulse coincides with the globally occurring Boda warming event, which also marks a time of global dispersal. In Iberia, this is reflected by almost entirely cosmopolitan brachiopod faunas, suggesting that the phases of rapid speciation which characterize the Ordovician Radiation had ceased by the mid-Katian.", "keyphrases": ["ordovician radiation", "speciation", "cambrian clade", "dispersal"]}
{"id": "10.1126/science.184.4139.903", "title": "Purgatorius, an Early Paromomyid Primate (Mammalia)", "abstract": "Fragmentary mandibles of Purgatorius unio Van Valen and Sloan from the Puercan (approximately early Paleocene), Garbani Locality, Montana, preserve associated postcanines. Their morphology indicates that this mammal was an early paromomyid primate and suggests that primate ancestry does not include currently known members of the palaeoryctid and leptictid Insectivora or of the Condylarthra.", "keyphrases": ["early paromomyid primate", "montana", "purgatorius"]}
{"id": "paleo.001019", "title": "Eptingiacea and Saturnaliacea (Radiolaria) from the middle Carnian of Turkey and some late Ladinian to early Norian samples from Oman and Alaska", "abstract": "This article is a taxonomic study of the radiolarian species of the superfamilies Eptingiacea and Saturnaliacea occurring in the middle Carnian fauna from the Ko \u00a8seyahya section, near the town of Elbistan, southeastern Turkey. This fauna is characteristic of the Tetraporobrachia haeckeli Radiolarian Zone as defined in Austria and later found also in Turkey and Oman. It comes from an 8 m thick succession of clayey/cherty limestones from the lower part of the section. In addition, a few species from the late Ladinian and Carnian from Oman and the early Norian from Alaska have also been included in this study, in order to improve some generic diagnoses and to show the diversity and evolutionary trends of some genera. 32 radiolarian species of which 22 are new are described and illustrated, and assigned to 16 genera of which three are new (Capnuchospyris, Veleptingium, and Triassolaguncula). The diagnoses of some species, genera, subfamilies and families have been revised, and the family Eptingiidae has been raised to the rank of superfamily.", "keyphrases": ["saturnaliacea", "turkey", "carnian fauna", "succession", "triassic spumellaria"]}
{"id": "10.1073/pnas.0709645105", "title": "Scale-dependence of Cope's rule in body size evolution of Paleozoic brachiopods", "abstract": "The average body size of brachiopods from a single habitat type increased gradually by more than two orders of magnitude during their initial Cambrian\u2013Devonian radiation. This increase occurred nearly in parallel across all major brachiopod clades (classes and orders) and is consistent with Cope's rule: the tendency for size to increase over geological time. The increase is not observed within small, constituent clades (represented here by families), which underwent random, unbiased size changes. This scale-dependence is caused by the preferential origination of new families possessing initially larger body sizes. However, this increased family body size does not confer advantages in terms of greater geological duration or genus richness over families possessing smaller body sizes. We suggest that the combination of size-biased origination of families and parallel size increases among major, more inclusive brachiopod clades from a single habitat type is best explained by long-term, secular environmental changes during the Paleozoic that provided opportunities for body size increases associated with major morphological evolution.", "keyphrases": ["cope", "brachiopod", "scale-dependence"]}
{"id": "10.1080/14772019.2012.660993", "title": "How many Pleistocene species of Lestodon (Mammalia, Xenarthra, Tardigrada)?", "abstract": "Among the Tardigrada (Mammalia, Xenarthra), terrestrial sloths were very abundant in the South American fauna during the Cenozoic and were especially well represented in the Lujanian (late Pleistocene\u2013early Holocene) fauna. The last systematic revision of the Pleistocene genus Lestodon from Argentina, Bolivia and Uruguay recognized two species: L. armatus Gervais, 1855 and L. australis Kraglievich, 1934. In this paper we revise the species of Lestodon and assess the possibility of sexual dimorphism in body size. The results obtained from a morphological study and morphometrical analysis of the skull do not support a distinction between the two species. Estimations of body mass based on tibial measurements did not support the case for size sexual dimorphism in Lestodon. Nor can this be observed in cranial dimensions. Consequently, it is proposed that the only valid species of the genus is L. armatus, the type species. We provide an emended diagnosis for L. armatus taking into account features found in specimens previously assigned to L. australis. Although the largest specimens of the genus Lestodon are from the current territory of Argentina, the average size of specimens from Uruguay is marginally larger. http://zoobank.org/urn:lsid:zoobank.org:pub:", "keyphrases": ["lestodon", "mammalia", "tardigrada"]}
{"id": "10.1080/14772019.2015.1043361", "title": "Redescription of Dapedium pholidotum (Agassiz, 1832) (Actinopterygii, Neopterygii) from the Lower Jurassic Posidonia Shale, with comments on the phylogenetic position of Dapedium Leach, 1822", "abstract": "Dapedium pholidotum (Agassiz, 1832) (Actinopterygii, Neopterygii) is redescribed based on new material from the Posidonia Shale (Early Jurassic: Early Toarcian) of Germany. Dapediiformes ord. nov. is introduced for Dapedium Leach, 1822 and other deep-bodied Mesozoic neopterygians. The species diagnosis of D. pholidotum is amended. Comparison with D. stollorum Thies & Hauff, 2011 and D. caelatum Quenstedt, 1858, also from the Lower Jurassic Posidonia Shale, shows that D. pholidotum is unique in having: (1) a length/height ratio of the operculum of c. 0.73, whereas in D. stollorum and D. caelatum this value reaches only c. 0.58; (2) a length/width ratio of the gular plate of c. 1.6, whereas in D. stollorum and D. caelatum this value is 1.3; (3) 27 or more caudal fin lepidotrichia, whereas in D. stollorum and D. caelatum there are 24 and 25 lepidotrichia, respectively; (4) at least 26 dorsal fin lepidotrichia, whereas D. stollorum and D. caelatum possess only 24 dorsal fin lepidotrichia each; and (5) a length/height ratio of the flank scales immediately behind the operculum of 0.37, whereas in D. stollorum and D. caelatum this ratio ranges around 0.31 and 0.5, respectively. A cladistic analysis based on modification of a previously published taxon\u2013character matrix shows that Dapedium is the sister group of the ginglymodian fishes [Semionotiformes + Lepisosteiformes]. The generic diagnosis of Dapedium Leach, 1822 is amended.", "keyphrases": ["dapedium pholidotum", "actinopterygii", "neopterygii"]}
{"id": "10.1080/14772019.2017.1296498", "title": "New late Paleocene (late middle Tiffanian) mammals from the Roche Perc\u00e9e local fauna, south-eastern Saskatchewan, Canada", "abstract": "An exceptionally large and diverse assemblage of mammals from the early late Paleocene (about 58 million years ago) has been collected from the Ravenscrag Formation near Roche Perc\u00e9e, south-eastern Saskatchewan, Canada. Previous research of the Roche Perc\u00e9e local fauna has examined only a small portion of the mammals, with the vast majority of taxa remaining unstudied. Identification and descriptions of these latter taxa are provided here. With these new additions, the assemblage is now known to include 44 mammalian species. Notable among these findings is the substantial collection of the erinaceomorph lipotyphlan Litocherus lacunatus, the remarkable diversity of viverravid carnivorans, and the recovery of some of the first known elements of the upper dentition of the pantolestid Besseocetor pilodontus. A complete description of the mammalian fauna supports previous assignments of a late middle Tiffanian North American Land Mammal Age (Ti4 lineage zone) to the Roche Perc\u00e9e local fauna. Faunal comparisons further suggest a close similarity of the Roche Perc\u00e9e assemblage to the near contemporaneous Divide Quarry local fauna from the Bighorn Basin, northern Wyoming, but also reveal some similarities to slightly older middle Tiffanian local faunas (Ti3 lineage zone) at localities in the Paskapoo Formation of central Alberta. The specimens from the Roche Perc\u00e9e local fauna represent the largest and most taxonomically diverse assemblage of late middle Tiffanian mammals yet known, offering a unique perspective on mammalian evolution and diversity in North America during this time interval.", "keyphrases": ["paleocene", "local fauna", "south-eastern saskatchewan"]}
{"id": "10.1002/jqs.1041", "title": "The chronology of abrupt climate change and Late Upper Palaeolithic human adaptation in Europe", "abstract": "This paper addresses the possible connections between the onset of human expansion in Europe following the Last Glacial Maximum, and the timing of abrupt climate warming at the onset of the Lateglacial (B\u00f6lling/Aller\u00f8d) Interstadial. There are opposing views as to whether or not human populations and activities were directly \u2018forced\u2019 by climate change, based on different comparisons between archaeological and environmental data. We review the geochronological assumptions and approaches on which data comparisons have been attempted in the past, and argue that the uncertainties presently associated with age models based on calibrated radiocarbon dates preclude robust testing of the competing models, particularly when comparing the data to non\u2010radiocarbon\u2010based timescales such as the Greenland ice core records. The paper concludes with some suggestions as to the steps that will be necessary if more robust tests of the models are to be developed in the future. Copyright \u00a9 2006 John Wiley & Sons, Ltd.", "keyphrases": ["climate change", "europe", "last glacial maximum"]}
{"id": "paleo.006734", "title": "Secondary Cartilage Revealed in a Non-Avian Dinosaur Embryo", "abstract": "The skull and jaws of extant birds possess secondary cartilage, a tissue that arises after bone formation during embryonic development at articulations, ligamentous and muscular insertions. Using histological analysis, we discovered secondary cartilage in a non-avian dinosaur embryo, Hypacrosaurus stebingeri (Ornithischia, Lambeosaurinae). This finding extends our previous report of secondary cartilage in post-hatching specimens of the same dinosaur species. It provides the first information on the ontogeny of avian and dinosaurian secondary cartilages, and further stresses their developmental similarities. Secondary cartilage was found in an embryonic dentary within a tooth socket where it is hypothesized to have arisen due to mechanical stresses generated during tooth formation. Two patterns were discerned: secondary cartilage is more restricted in location in this Hypacrosaurus embryo, than it is in Hypacrosaurus post-hatchlings; secondary cartilage occurs at far more sites in bird embryos and nestlings than in Hypacrosaurus. This suggests an increase in the number of sites of secondary cartilage during the evolution of birds. We hypothesize that secondary cartilage provided advantages in the fine manipulation of food and was selected over other types of tissues/articulations during the evolution of the highly specialized avian beak from the jaws of their dinosaurian ancestors.", "keyphrases": ["non-avian dinosaur embryo", "nestling", "secondary cartilage"]}
{"id": "10.1080/14772019.2020.1784300", "title": "A new species of glyptodontine (Mammalia, Xenarthra, Glyptodontidae) from the Quaternary of the Eastern Cordillera, Bolivia: phylogeny and palaeobiogeography", "abstract": "Xenarthrans constitute a relict clade of endemic South American placental mammals with a long evolutionary history starting, at least, in the early Eocene. Within Xenarthra, Glyptodontidae (late Eocene\u2013earliest Holocene) was a conspicuous group of large-sized armoured herbivores. During the Pleistocene (ca. 2.6\u20130.001\u2009Ma) several genera (e.g. Panochthus and Glyptodon) achieved a remarkable latitudinal distribution in South America, as members of one of the xenarthran groups that participated in the Great American Biotic Interchange. Knowledge of the evolutionary history of this clade in some areas remains poorly known, especially in the high elevation Andean and sub-Andean regions of South America. Here we describe a new species, Glyptodon jatunkhirkhi sp. nov., from several localities of the Eastern Cordillera in Bolivia (ca. 2500\u20134100 m above sea level). From a phylogenetic viewpoint this new taxon appears as the sister group of the two lowland species recorded in southern South America (Glyptodon munizi + G. reticulatus), and this is congruent with the morphological differences observed between both clades, mainly with respect to the general morphology of the dorsal carapace and the skull. This new species expands the complex biogeographical scenario for Pleistocene glyptodonts and highlights the importance of Andean areas as key in understanding the evolutionary history of this clade. According to this revision, the diversity of Glyptodon is limited to G. munizi and G. reticulatus (two chronologically successive lowland species) plus this new species. The genera Panochthus (P. hipsilis) and Glyptodon seem to be the only Pleistocene glyptodonts to have been adapted to high elevation environments. http://zoobank.org/urn:lsid:zoobank.org:pub:7B5EFC11-626A-4BB5-8A00-DF657741698C", "keyphrases": ["xenarthra", "glyptodontidae", "eastern cordillera"]}
{"id": "paleo.008102", "title": "Phylogeny and Biogeography of Pholadid Bivalve Barnea (Anchomasa) with Considerations on the Phylogeny of Pholadoidea", "abstract": "The paper examines the systematics, phylogeny and biogeographical history of Barnea (Anchomasa), which is one of the most abundant and diversified of modern pholadid bivalves. The range of morphology of its distinctive characters and comparisons with other pholadoidean taxa are described in detail. An extensive cladistic analysis based on morphological characters at genus and subgenus levels allowed the inclusion of B. (Anchomasa) into the phylogeny of Pholadoidea and the establishment of its most appropriate taxonomic position. The analysis confirms that Barnea s.s. and B. (Umitakea) are its closest relatives and that the morphological similarities to other taxa are mainly due to plesiomorphies. The fossil record and the data on the present-day distribution contributed to trace the biogeographical history of B. (Anchomasa). The present-day biogeography is marked by the disjunct distribution of species. Species are distributed mainly either along the Atlantic and Pacific coasts of the American continent (American group) or in the Indo-West Pacific region (Indo-West Pacific group). Both these groups have distinct morphological features and biogeographical structures. The fossil record and the known geodynamic scenario suggest a relationship of direct derivation between the Indo-West Pacific group and a stock of north-eastern Atlantic to Paratethyan species. This reflects a vicariant event related to the closure of the connection between western Tethys and the Indian Ocean in the middle Miocene. The American group presumably arose from the European stock during the Late Pliocene by dispersal towards the eastern coasts of North America and rapid southward diffusion. A relative differentiation within the American group is probably related to the last phases of emergence of the Panama Isthmus. The cladistic analysis also gives suggestions for the reconstruction of the phylogeny of the superfamily Pholadoidea. It confirms the interpretation of several characters sustained by previous authors. However, it also shows remarkable differences to the previous taxonomic arrangements. Pholadinae includes only taxa having the protoplax and it appears to be the sister-group of a major clade composed mainly of two groups, namely Martesiinae-Jouannetiinae and Xylophagainae\u2014Teredinidae. The Martesiinae are paraphyletic whereas the obligate wood-boring Xylophagainae and Teredinidae form a well-supported monophyletic group.", "keyphrases": ["biogeography", "anchomasa", "pholadoidea"]}
{"id": "10.1029/2006GL026011", "title": "Global gridded data set of the oxygen isotopic composition in seawater", "abstract": "We present a new 3\u2010dimensional 1\u00b0 \u00d7 1\u00b0 gridded data set for the annual mean seawater oxygen isotope ratio (\u03b418O) to use in oceanographic and paleoceanographic applications. It is constructed from a large set of observations made over the last 50 years combined with estimates from regional \u03b418O to salinity relationships in areas of sparse data. We use ocean fronts and water mass tracer concentrations to help define distinct water masses over which consistent local relationships are valid. The resulting data set compares well to the GEOSECS data (where available); however, in certain regions, particularly where sea ice is present, significant seasonality may bias the results. As an example application of this data set, we use the resulting surface \u03b418O as a boundary condition for isotope\u2010enabled GISS ModelE to yield a more realistic comparison to the isotopic composition of precipitation data, thus quantifying the \u2018source effect\u2019 of \u03b418O on the isotopic composition of precipitation.", "keyphrases": ["data set", "isotopic composition", "seawater", "precipitation"]}
{"id": "10.5252/g2013n1a6", "title": "Bizarre fossil beaked whales (Odontoceti, Ziphiidae) fished from the Atlantic Ocean floor off the Iberian Peninsula", "abstract": "ABSTRACT Forty partial fossil skulls belonging to beaked whales (Cetacea, Odontoceti, Ziphiidae) were collected by trawling and long-line fishing on Neogene (probably Late Early to Middle Miocene) layers of the Atlantic floor off the coasts of Portugal and Spain (Asturias and Galicia). The systematic study of the most diagnostic Iberian specimens, those preserving the rostrum and the dorsal part of the cranium, led to the recognition of two new genera (Globicetus n. gen. and Imocetus n. gen.) and four new species (Choneziphius leidyi n. sp., G. hiberus n. gen., n. sp., I. piscatus n. gen., n. sp., and Tusciziphius atlanticus n. sp.). Based on the matrix of a previous work, the phylogenetic analysis places all the new taxa in the subfamily Ziphiinae Gray, 1850. More fragmentary specimens are tentatively referred to the genera Caviziphius Bianucci & Post, 2005 and Ziphirostrum du Bus, 1868. Among these new ziphiids, extremely bizarre skull morphologies are observed. In G. hiberus n. gen., n. sp. the proximal portion of the rostrum bears a voluminous premaxillary spheroid. In T. atlanticus n. sp. a medial premaxillary bulge is present on the rostrum; together with asymmetric rostral maxillary eminences at the rostrum base, this bulge displays various degrees of elevation in different specimens, which may be interpreted as sexual dimorphism. Specimens of I. piscatus n. gen., n. sp. bear two sets of even crests: spur-like rostral maxillary crests and longitudinal maxillary crests laterally bordering a wide and long facial basin. A preliminary macroscopic observation of these elements indicates very dense bones, with a compactness comparable with that of cetacean ear bones. Questioning their function, the high medial rostral elements (the premaxillary spheroid of G. hiberus n. gen., n. sp. and the medial bulge of T. atlanticus n. sp.) remind the huge rostral maxillary crests of adult males of the extant Hyperoodon ampullatus (Forster, 1770). In the latter, the crests are very likely related to head-butting. However, they are made of much more spongy bone than in the fossil taxa studied here, and therefore possibly better mechanically suited for facing impacts. Other interpretations of these unusual bone specializations, related to deep-diving (ballast) and echolocation (sound reflection), fail to explain the diversity of shapes and the hypothetical sexual dimorphism observed in at least part of the taxa. The spur-like rostral maxillary crests and long maxillary crests limiting the large facial basin in I. piscatus n. gen., n. sp. and the excrescences on the maxilla at the rostrum base in Choneziphius spp. are instead interpreted as areas of origin for rostral and facial muscles, acting on the nasal passages, blowhole, and melon. From a palaeobiogeographic point of view, the newly described taxa further emphasize the differences in the North Atlantic (including Iberian Peninsula) and South African Neogene ziphiid faunal lists. Even if the stratigraphic context is poorly understood, leaving open the question of the geological age for most of the dredged specimens, these differences in the composition of cold to temperate northern and southern hemisphere fossil ziphiid faunas may be explained by a warm-water equatorial barrier.", "keyphrases": ["whale", "ziphiidae", "iberian peninsula"]}
{"id": "paleo.012704", "title": "Constraining uncertainty in the timescale of angiosperm evolution and the veracity of a Cretaceous Terrestrial Revolution", "abstract": "Summary Through the lens of the fossil record, angiosperm diversification precipitated a Cretaceous Terrestrial Revolution (KTR) in which pollinators, herbivores and predators underwent explosive co\u2010diversification. Molecular dating studies imply that early angiosperm evolution is not documented in the fossil record. This mismatch remains controversial. We used a Bayesian molecular dating method to analyse a dataset of 83 genes from 644 taxa and 52 fossil calibrations to explore the effect of different interpretations of the fossil record, molecular clock models, data partitioning, among other factors, on angiosperm divergence time estimation. Controlling for different sources of uncertainty indicates that the timescale of angiosperm diversification is much less certain than previous molecular dating studies have suggested. Discord between molecular clock and purely fossil\u2010based interpretations of angiosperm diversification may be a consequence of false precision on both sides. We reject a post\u2010Jurassic origin of angiosperms, supporting the notion of a cryptic early history of angiosperms, but this history may be as much as 121 Myr, or as little as 23 Myr. These conclusions remain compatible with palaeobotanical evidence and a more general KTR in which major groups of angiosperms diverged later within the Cretaceous, alongside the diversification of pollinators, herbivores and their predators.", "keyphrases": ["timescale", "angiosperm evolution", "cretaceous terrestrial revolution", "diversification"]}
{"id": "10.2138/am-2016-5737", "title": "From bone to fossil: A review of the diagenesis of bioapatite", "abstract": "Abstract The preservation of bone or bioapatite over geologic time has presented paleobiologists with long-standing and formidable questions. Namely, to elucidate the mechanisms, processes, rates, and depositional conditions responsible for the formation of a fossil from a once living tissue. Approaches integrating geochemistry, mineralogy, physics, hydrology, sedimentology, and taphonomy have all furthered insights into fossilization, but several fundamental gaps still remain. Notably, our limited understanding of: (1) the timing of processes during diagenesis (e.g., early and/or late), (2) the rate of bioapatite transformation into thermodynamically more stable phases, (3) the controls imparted by depositional environment, and (4) the role of (micro)biology in determining the fate of bone bioapatite (dissolution or preservation). The versatility of fossil bioapatite to provide information on the biology of extinct vertebrates rests on our ability to identify and characterize the changes that occurred to bioapatite during diagenesis. This review will evaluate our current understanding of bioapatite diagenesis and fossilization, focusing on the biogeochemical transformations that occur during diagenesis to the mineral and organic components of bone (excluding teeth and enamel), the analytical approaches applied to evaluate fossilization processes, and outline some suggestions for future promising directions.", "keyphrases": ["review", "diagenesis", "bioapatite", "fossilization process"]}
{"id": "10.1098/rspb.2008.1473", "title": "Marine mammals through time: when less is more in studying palaeodiversity", "abstract": "The validity of biological explanations of patterns of palaeodiversity has been called into question owing to an apparent correlation of diversity with the amount of sedimentary rock preserved. However, this claim has largely been based on comprehensive estimates of global marine Phanerozoic diversity, thus raising the question of whether a similar bias applies to the records of smaller, well-defined taxonomic groups. Here, new data on European Caenozoic marine sedimentary rock outcrop area are presented and compared with European occurrences of three groups of marine mammals (cetaceans, pinnipedimorphs and sirenians). Limited evidence was found for a correlation of outcrop area with marine mammal palaeodiversity. In addition, similar patterns were identified in the cetacean and pinnipedimorph diversity data. This may point to the preservation of a genuine biological signal not overwhelmed by geological biases in the marine mammal diversity data, and opens the door to further analyses of both marine mammal evolution and geological bias in other small and well-defined groups of taxa.", "keyphrases": ["palaeodiversity", "sirenian", "marine mammal"]}
{"id": "10.1002/2016PA002957", "title": "Strong middepth warming and weak radiocarbon imprints in the equatorial Atlantic during Heinrich 1 and Younger Dryas", "abstract": "We present a benthic foraminiferal multiproxy record of eastern equatorial Atlantic (EEA) middepth water (1295m) covering the last deglacial. We show that EEA middepth water temperatures were elevated by 3.90.5 degrees C and 5.21.2 degrees C during Heinrich event 1 (H1) and Younger Dryas (YD), respectively. The radiocarbon content of the EEA middepth during H1 and YD is relatively low and comparable to the values of the pre-H1 episode and BOlling-AllerOd, respectively. A transient Earth system model simulation, which mimics the observed deglacial Atlantic Meridional Overturning Circulation (AMOC) history, qualitatively reproduces the major features of the EEA proxy records. The simulation results suggest that fresh water-induced weakening of the AMOC leads to a vertical shift of the horizon of Southern Ocean-sourced water and a stronger influence of EEA sea surface temperatures via mixing. Our findings reaffirm the lack of a distinctive signature of radiocarbon depletion and therefore do not support the notion of interhemispheric exchanges of strongly radiocarbon-depleted middepth water across the tropical Atlantic during H1 and YD. Our temperature reconstruction presents a critical zonal and water depth extension of existing tropical Atlantic data and documents a large-scale and basin-wide warming across the thermocline and middepth of the tropical Atlantic during H1 and YD. Significant difference in the timing and pace of H1 middepth warming between tropical Atlantic and North Atlantic likely points to a limited role of the tropical Atlantic middepth warming in the rapid heat buildup in the North Atlantic middepth.", "keyphrases": ["middepth warming", "equatorial atlantic", "younger dryas"]}
{"id": "10.1080/02724634.1994.10011525", "title": "The skull and neck of the basal theropod Herrerasaurus ischigualastensis", "abstract": "ABSTRACT We describe the skull and neck of Herrerasaurus ischigualastensis from specimens discovered recently in the Upper Triassic Ischigualasto Formation of northwestern Argentina. The skull has a rectangular profile and a transversely narrow snout. Marked supratemporal depressions for jaw adductor musculature on the skull roof and a well-developed, sliding intra-mandibular joint suggest that Herrerasaurus ischigualastensis was an active predator. The neck is relatively slender with prominent epipophyses on all of the cervical vertebrae. Diagnostic features of the species include the semicircular shape of the antorbital fossa and the long, slender posterodorsal process of the dentary. Other features of the skull, such as the loss of the postfrontal and small post-temporal opening, constitute dinosaurian synapomorphies. These synapomorphies, however, remain equivocal at the level of Dinosauria because they cannot be evaluated in immediate dinosaurian outgroups for which cranial information is lacking. Co...", "keyphrases": ["skull", "neck", "herrerasaurus ischigualastensis"]}
{"id": "10.2113/174.3.279", "title": "The mammal localities of Grand Daoui Quarries, Ouled Abdoun Basin, Morocco, Ypresian : A first survey", "abstract": "The unexpected discovery of mammals such as the earliest known proboscidean Phosphatherium escuilliei in the Ouled Abdoun phosphate Basin (Morocco), which is otherwise renowned for its very rich marine vertebrate fauna, has opened major new perspectives on the early African placental fauna. It was the impetus for several field parties by us between 1997 and 2001 which has allowed this survey of the geological, stratigraphic and paleontological context of Phosphatherium localities. This is the first important paleontological field work dealing with higher vertebrates in the Ouled Abdoun Basin since the work of C. Arambourg.\n\nMost of the material of Phosphatherium and other Ouled Abdoun mammals was found by local people searching for fossils for dealing, in an area where the economy is widely dominated by the mining development, in addition to more traditional but very poor agricultural resources. All Phosphatherium remains were found in the northeasternmost quarries of the Ouled Abdoun Basin, from a restricted quarrying area called Grand Daoui (fig. 3). In all Grand Daoui recognized localities (8), the mammals come from the lowermost Eocene level. The stratigraphically re-situated mammalian material was found in a bone-bed of the level called \"Intercalaire Couches II/I\" which is dated as early(iest) Ypresian on the basis of its relative stratigraphic position and its selachian fauna. At present, the occurrence of several mammal horizons in the \"Intercalaire Couches II/I\" (and Couche I ?) cannot be excluded, but their age difference seems not significant according to both the associated selachian taxa and the mammalian material, in present data. The bone-bed is very rich in macro-vertebrates. It includes especially large teeth of the shark Otodus obliquus which are the subject of very active research for dealing, and which explains the recent discovery of mammals such as Phosphatherium\n\nThe level \"Intercalaire Couches II/I\" is made of a hardened phosphatic bioclastic limestone which is separated from underlying Paleocene levels by a major discontinuity. It is the first deposit of the Eocene sequence (megasequence C) in the Ouled Abdoun phosphate series. Deposition of this new sequence partly reworked the underlying Thanetian levels in the lowermost horizons of the level \"Intercalaire Couches II/I\", such as the mammals bearing bone-bed. This explains the recovery of Thanetian selachians in the matrix of the holotype of P. escuilliei and its initial allocation to the Thanetian by Gheerbrant et al. [1996, 1998]. These Thanetian selachian species are now clearly recognized as reworked. Studies of new samples of selachians associated with the newly recovered remains of P. escuilliei and other Grand Daoui mammals have confirmed our field observations owing to the identification of typical early Ypresian species which are listed in table I. P. escuilliei and other mammals from Grand Daoui quarries are confidently dated here as early(iest) Ypresian.\n\nAs a general rule, there is no known concentration of fossil remains of species of terrestrial origin in the Ouled Abdoun epicontinental Basin. The mammals are exceedingly rare, documented by very few occurrences in contrast to the associated very rich marine vertebrate remains in the phosphate deposits. The occurrence of several rare mammals in these marine facies is related to a peculiar taphonomy characterized by a transport from near shores and continental hinterland under conditions of low hydrodynamic energy such as floated bodies. This is consistent with both the scattered nature of the material in the basin and with its well preserved state (e.g., dental rows, skulls) with respect to other early African mammal localities such as the Ouarzazate basin sites.\n\nUp to now, the Grand Daoui sites have yielded 7 species of mammals, which is not an inconsiderable diversity. The provisional faunal list includes a new hyaenodontid creodont, a small (P. escuilliei) and a large (Daouitherium rebouli) proboscidean, the two \"condylarths\" Abdounodus hamdii (cf. Mioclaneidae) and Ocepeia daouiensis (cf. Phenacodonta), and two indeterminate species which are described here. One of these, known only by a broken bilophodont lower molar, might belong to a new \"condylarth\" or a new ungulate. It has a reduced one-rooted M/3. An isolated M/3 belongs to another new species close to the genus Seggeurius. It is the oldest known hyracoidean along with an indeterminate species from the Ypresian of N'Tagourt 2 (Morocco).\n\nIn the mammalian Ouled Abdoun \u00ab fauna \u00bb, P. escuilliei is largely predominant. As a whole this \"fauna\" shows typical endemic African affinities. It provides new insight into the origin and initial radiation of major endemic African placental taxa. Despite their scarcity, the well preserved Ouled Abdoun mammal remains provide new data especially on the earliest known African ungulates. This is indeed the only known locality bearing large mammals in the Paleocene and early Eocene of Africa, probably in connection to the peculiar taphonomy of continental vertebrates in the phosphatic facies.\n\nThe vertebrates associated with the Grand Daoui mammals include selachians, osteichthyans, marine reptiles (crocodilians, turtles, and the snakes Palaeophis) and also marine birds which are here reported for the first time in the Ouled Abdoun and other African phosphate basins. The Ouled Abdoun birds are diversified and much less rare than the mammals. They are the oldest known birds in Africa and among the oldest representatives of modern marine groups. Preliminary identifications indicate the occurrence of Procellariiformes (cf. Diomedeidae, cf. Procellariidae), Pelecaniformes (cf. Phaethontidae, cf. Prophaethontidae, cf. Fregatidae, cf. Pelagornithidae), and Anseriformes (cf. Presbyornithidae).", "keyphrases": ["mammal locality", "ouled abdoun basin", "morocco"]}
{"id": "paleo.001147", "title": "Articulated avian remains from the early Oligocene of Poland adds to our understanding of Passerine evolution", "abstract": "In total, less than 50 specimens of the Passeriformes are known from the Paleogene, which contrasts with the fact that now it is the largest and most diverse order of birds. The so far described fossils include only three nearly complete specimens, an articulated wing and legs, and a handful of isolated bones. This paper describes a new species and genus of a passerine bird the size of the extant Parus major, imprinted on a slab and a counter slab of the siliceous clayey shales of the Outer Carpathians in southeastern Poland, and dated to the Rupelian, early Oligocene (ca. 31 m.y.a.). It is one of the very few passerine specimens from the Paleogene with bones in articulation, and thus provides a window into the ancestral osteology of passeriforms, which is characterized by a mosaic of characters typical for extant Oscines and Suboscines. The bird shows a unique manus, with a relatively short carpometacarpus and cleavershaped phalanx proximalis digiti majoris. Besides bones, fragmentary feathers are also imprinted on both slabs. Zbigniew M. Bochenski. Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland. (corresponding author) bochenski@isez.pan.krakow.pl Teresa Tomek. Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland. tomek@isez.pan.krakow.pl Krzysztof Wertz. Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, Slawkowska 17, 31-016 Krakow, Poland. wertz@isez.pan.krakow.pl Johannes Happ. Department of Palaeontology, Faculty of Earth Sciences, University of Vienna, Vienna, Austria. johanneshapp@yahoo.de Ma\u0142gorzata Bujoczek. Department of Forest Biodiversity, Faculty of Forestry, University of Agriculture, al. 29 Listopada 46, 31-425 Krakow, Poland. malgorzata.bujoczek@urk.edu.pl Ewa Swidnicka. Department of Palaeozoology, Institute of Environmental Biology, Faculty of Biological Sciences, University of Wroc\u0142aw, Sienkiewicza 21, 50-335 Wroc\u0142aw, Poland. gama@biol.uni.wroc.pl http://zoobank.org/DDC682C0-D2BD-44FF-B8F2-E48B940DC7D4 Bochenski, Zbigniew M., Tomek, Teresa, Wertz, Krzysztof, Happ, Johannes, Bujoczek, Ma\u0142gorzata, and Swidnicka, Ewa. 2018. Articulated avian remains from the early Oligocene of Poland adds to our understanding of Passerine evolution. Palaeontologia Electronica 21.2.32A 1-12. https://doi.org/10.26879/843 palaeo-electronica.org/content/2018/2300-passerine-bird-from-oligocene Copyright: August 2018 Paleontology Society. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ BOCHENSKI: PASSERINE BIRD FROM OLIGOCENE", "keyphrases": ["avian", "early oligocene", "passerine evolution"]}
{"id": "10.1080/14772019.2019.1634649", "title": "Scheenstia bernissartensis (Actinopterygii: Ginglymodi) from the Early Cretaceous of Bernissart, Belgium, with an appraisal of ginglymodian evolutionary history", "abstract": "Lepidotes bernissartensis is a species of holostean ray-finned fish from the Barremian\u2013Aptian of Bernissart, Belgium, described by Traquair in 1911. We provide here a revision of its anatomy, which led us to include this species in the genus Scheenstia, and to consider L. brevifulcratus and L. arcuatus, both from the same site, synonymous with S. bernissartensis. We performed two cladistic analyses in order to assess the phylogenetic position of S. bernissartensis and to do an updated appraisal of the evolutionary history of the ginglymodians. Scheenstia is included in the Lepidotidae, and placed in a pectinated position between the basal genus Lepidotes and the more derived members of the family (other species of Scheenstia, Isanichthys and Camerichthys). The nodes within the lepidotids are weakly supported. Although S. bernissartensis is not directly related to S. mantelli from the Wealden of Europe, the two species have similar palaeoenvironments and stratigraphical ranges. Taken as a whole, the ginglymodians experienced several episodes of diversification that are spatially and temporally restricted. The oldest episode involved basal ginglymodians and occurred in the Middle Triassic, in marine environments along the northern margin of the Tethys. A second episode affected the Semionotidae and occurred in freshwater environments of North America and Europe in the Late Triassic and Early Jurassic. The remaining Semionotiformes, Macrosemiidae and Callipurbeckidae, ranged from the Triassic to the Early Cretaceous and were mostly marine. Among the Lepisosteiformes, two clades, the Lepidotidae and the Lepisosteoidi, show episodes of diversification, first in marine and then in freshwater environments.", "keyphrases": ["early cretaceous", "evolutionary history", "scheenstia bernissartensis"]}
{"id": "10.1017/s0094837300010034", "title": "Sutural pattern and shell stress in Baculites with implications for other cephalopod shell morphologies", "abstract": "In Baculites, a straight shelled ammonite, the constructional limits on shell shape resulting from the limited strength of nacre in tension are circumvented by a system of vaults in the phragmocone. Vaults bridge between regions of the phragmocone supported by the complex ammonite septal suture, and maintain the shell wall in compression when hydrostatic load induces bending moments. To determine how these vaults interact in the phragmocone to resist hydrostatic loading, measurements were made on a suite of Baculites specimens. In Baculites there is a statistically significant inverse relationship between circumferential curvature (radius of curvature) of the vaulted shell surface and the size of vaults spanning between sutural elements supporting the phragmocone. The inverse relationship between radius of curvature and the sizes of spans in this system of vaults results in the generation of comparable reactive forces at the ends of the vault spans where adjacent vaults interact. The equivalence of these reactive forces prevents the lateral displacement of the vault ends. Consequently, compressive stresses from adjacent vaults are superimposed on, and reduce, the tensional stress component of bending. Limiting tensile stress is of utmost importance in a lightweight shell composed of a brittle material such as nacre, which is strong in compression but weak in tension. Baculites is particularly appropriate for this study because its straight shell is curved only in the circumferential direction, thus simplifying the problem. However, sutural patterns in coiled ammonites appear to be similarly constrained to produce vaults in the phragmocone which vary inversely in curvature and span size.", "keyphrases": ["stress", "baculite", "sutural pattern"]}
{"id": "10.1017/S1477201907002398", "title": "Phylogenetic affinities of the enigmatic avian taxon zygodactylus based on new material from the early oligocene of France", "abstract": "Synopsis Until now, the avian taxon Zygodactylus has been known only from distal tibiotarsi and tarsometatarsi from the early Miocene of Europe. Although the tarsometatarsus exhibits derived similarities to that of extant Pici (barbets, toucans, woodpeckers and their allies), it differs in many aspects and the phylogenetic affinities of Zygodactylus were uncertain. Here, a well\u2010preserved skeleton with a tentatively referred skull is described from the early Oligocene of the Luberon, southern France, as a new species, Z. luberonensis. It is about 10 million years older than previously assigned species and exhibits derived characters which support a clade comprising Zygodactylus and Eocene zygodactyl birds that were assigned to the taxon \u2018Primoscenidae\u2019. Primoscenidae Harrison & Walker, 1977 is synonymised with Zygodactylidae Brodkorb, 1971. Zygodactylus lacks derived features of crown group Piciformes and the derived similarities in the distal tarsometatarsi of Zygodactylus and the Pici are thus a striking example of convergence. Instead, the analysis results in a sister group relationship between Zygodactylidae and Passeriformes (passerines), and morphological characters are listed which support this hypothesis. Recognition of Zygodactylidae as the possible sister taxon of the Passeriformes implies that stem group representatives of passerines already existed by the early Eocene.", "keyphrases": ["avian taxon zygodactylus", "early oligocene", "passeriformes", "phylogenetic affinity"]}
{"id": "10.1666/13-025", "title": "Partial Skeleton of a Bony-Toothed Bird from the Late Oligocene/Early Miocene of Oregon (USA) and the Systematics of Neogene Pelagornithidae", "abstract": "Abstract A partial skeleton of a pelagornithid bird found in latest Oligocene or earliest Miocene marine strata in Oregon consists of a pelvis fragment, thoracic vertebrae, and leg bones of a single individual. It is the most completely preserved pelagornithid from the late Oligocene/early Miocene, and one of the few bony-toothed birds from this time period in general. The new fossil is from the Nye Mudstone and shows some previously unknown features that contribute to a better understanding of the osteology of pelagornithids. Because Paleogene and late Neogene pelagornithids differ in several osteological features and the temporally intermediate forms are poorly known, it further bridges a gap in our knowledge of character evolution in pelagornithids. The interrelationships within Pelagornithidae are still poorly resolved, but we detail that a clade of Neogene species, which the Oregon pelagornithid is not part of, can be supported by a derived morphology of the femur. To ease description of Neogene pelagornithids, we synonymize Palaeochenoides Shufeldt, 1916 and Tympanonesiotes Hopson, 1964 with Pelagornis Lartet, 1857, and suggest classification of all Neogene pelagornithids in the latter taxon.", "keyphrases": ["bony-toothed bird", "early miocene", "partial skeleton"]}
{"id": "10.1017/jpa.2018.17", "title": "Rautangaroa, a new genus of feather star (Echinodermata, Crinoidea) from the Oligocene of New Zealand", "abstract": "Abstract. We describe a nearly complete, and thus extremely rare, feather star (Crinoidea, Comatulida) from Oligocene strata of North Otago/South Canterbury, New Zealand. A detailed analysis of this specimen, as well as newly recovered material and previously described fragmentary remains from nearby contemporaneous sedimentary units, in addition to relevant historical specimens, lead us to conclude that it cannot be placed in any currently established genus. A new genus, Rautangaroa, is proposed to accommodate it. This intact specimen of Rautangaroa aotearoa (Eagle, 2007), provides rare data on the morphology of arms and cirri. It represents the first example of arm autotomy and regeneration in a fossil feather star and thus has bearing on the importance of predation to the evolutionary history of this group.", "keyphrases": ["new genus", "feather star", "crinoidea"]}
{"id": "paleo.000574", "title": "Tetrapod postural shift estimated from Permian and Triassic trackways", "abstract": "Abstract:\u2002 The end\u2010Permian mass extinction, 252\u2003million years (myr) ago, marks a major shift in the posture of tetrapods. Before the mass extinction, terrestrial tetrapods were sprawlers, walking with their limbs extended to the sides; after the event, most large tetrapods had adopted an erect posture with their limbs tucked under the body. This shift had been suspected from the study of skeletal fossils, but had been documented as a long process that occupied some 15\u201320\u2003myr of the Triassic. This study reads posture directly from fossil tracks, using a clear criterion for sprawling vs erect posture. The track record is richer than the skeletal record, especially for the Early and Middle Triassic intervals, the critical 20\u2003myr during which period the postural shift occurred. The shift to erect posture was completed within the 6\u2003myr of the Early Triassic and affected both lineages of medium to large tetrapods of the time, the diapsids and synapsids.", "keyphrases": ["postural shift", "mass extinction", "tetrapod"]}
{"id": "paleo.007159", "title": "THE CENOZOIC DEEP SEA MICROFOSSIL RECORD: EXPLORATIONS OF THE DSDP/ODP SAMPLE SET USING THE NEPTUNE DATABASE", "abstract": "For 30 years the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) have been drilling the ocean floors and retrieving sediment cores. This study presents a relational micropaleontological and stratigraphic database, Neptune, where a selection of the published studies made on these sediments is available. The selected sites and their stratigraphic extent represent a statistically reproducible subset of the whole DSDP and ODP data set as of 1995 (up to Leg 135). Cenozoic sediments from 165 globally distributed holes were dated with age/depth plots using biochronology of four marine plankton groups (diatoms, nannofossils, foraminifera, and radiolarians). Each hole's location is available with paleogeographic coordinates. A taxonomic revision of the 8000+ reported species names was also made. The database is searchable and a variety of routines are available. Data can be exported to produce age range charts, geographic distribution maps, and occurrence charts.\nA rigorous evaluation of the database potentials and limitations is presented together with a summary of the published studies that have been carried on with the data. These include stratigraphic studies (diachrony of Neogene plankton, hiati distribution in Cenozoic sediments) and evolution studies (cladogenesis and evolution of one foraminiferal lineage). Unpublished data on macroevolutionary patterns (species longevity and richness, speciation and extinction rates) are presented as example of Neptune's potential for paleobiological research. Finally, some suggestions are presented as to how Neptune can be more fully exploited through the addition of sedimentologic and isotopic data. A variety of critical sedimentologic and paleoceanographic questions could be addressed with this extended database.", "keyphrases": ["cenozoic", "dsdp", "neptune", "nannofossil", "foraminifera"]}
{"id": "10.1111/j.1525-142X.2010.00403.x", "title": "Are palaeoscolecids ancestral ecdysozoans?", "abstract": "SUMMARY The reconstruction of ancestors is a central aim of comparative anatomy and evolutionary developmental biology, not least in attempts to understand the relationship between developmental and organismal evolution. Inferences based on living taxa can and should be tested against the fossil record, which provides an independent and direct view onto historical character combinations. Here, we consider the nature of the last common ancestor of living ecdysozoans through a detailed analysis of palaeoscolecids, an early and extinct group of introvert\u2010bearing worms that have been proposed to be ancestral ecdysozoans. In a review of palaeoscolecid anatomy, including newly resolved details of the internal and external cuticle structure, we identify specific characters shared with various living nematoid and scalidophoran worms, but not with panarthropods. Considered within a formal cladistic context, these characters provide most overall support for a stem\u2010priapulid affinity, meaning that palaeoscolecids are far\u2010removed from the ecdysozoan ancestor. We conclude that previous interpretations in which palaeoscolecids occupy a deeper position in the ecdysozoan tree lack particular morphological support and rely instead on a paucity of preserved characters. This bears out a more general point that fossil taxa may appear plesiomorphic merely because they preserve only plesiomorphies, rather than the m\u00e9lange of primitive and derived characters anticipated of organisms properly allocated to a position deep within animal phylogeny.", "keyphrases": ["palaeoscolecid", "ancestral ecdysozoan", "scalidophoran"]}
{"id": "paleo.012397", "title": "Compilation and Network Analyses of Cambrian Food Webs", "abstract": "A rich body of empirically grounded theory has developed about food webs\u2014the networks of feeding relationships among species within habitats. However, detailed food-web data and analyses are lacking for ancient ecosystems, largely because of the low resolution of taxa coupled with uncertain and incomplete information about feeding interactions. These impediments appear insurmountable for most fossil assemblages; however, a few assemblages with excellent soft-body preservation across trophic levels are candidates for food-web data compilation and topological analysis. Here we present plausible, detailed food webs for the Chengjiang and Burgess Shale assemblages from the Cambrian Period. Analyses of degree distributions and other structural network properties, including sensitivity analyses of the effects of uncertainty associated with Cambrian diet designations, suggest that these early Paleozoic communities share remarkably similar topology with modern food webs. Observed regularities reflect a systematic dependence of structure on the numbers of taxa and links in a web. Most aspects of Cambrian food-web structure are well-characterized by a simple \u201cniche model,\u201d which was developed for modern food webs and takes into account this scale dependence. However, a few aspects of topology differ between the ancient and recent webs: longer path lengths between species and more species in feeding loops in the earlier Chengjiang web, and higher variability in the number of links per species for both Cambrian webs. Our results are relatively insensitive to the exclusion of low-certainty or random links. The many similarities between Cambrian and recent food webs point toward surprisingly strong and enduring constraints on the organization of complex feeding interactions among metazoan species. The few differences could reflect a transition to more strongly integrated and constrained trophic organization within ecosystems following the rapid diversification of species, body plans, and trophic roles during the Cambrian radiation. More research is needed to explore the generality of food-web structure through deep time and across habitats, especially to investigate potential mechanisms that could give rise to similar structure, as well as any differences.", "keyphrases": ["food webs", "burgess shale", "diversification", "complex marine ecosystem", "cambrian explosion"]}
{"id": "10.1073/pnas.1605051113", "title": "Belowground rhizomes in paleosols: The hidden half of an Early Devonian vascular plant", "abstract": "Significance The roots and rhizomes of early vascular plants, and their interactions with soils, are poorly documented. Here we report on the complex, belowground rhizome systems of an Early Devonian plant, and their contribution to the formation of the earliest record of rooted red-bed soils in Asia. Our specimens predate the earliest trees with deep roots from the Middle Devonian by 20 million years. We propose that plant rhizomes have long functioned in terrestrial ecosystems, playing important roles in shaping Earth\u2019s environments by reducing soil erosion rates and thereby increasing the stability of land surface and resilience of plant communities. The colonization of terrestrial environments by rooted vascular plants had far-reaching impacts on the Earth system. However, the belowground structures of early vascular plants are rarely documented, and thus the plant\u2212soil interactions in early terrestrial ecosystems are poorly understood. Here we report the earliest rooted paleosols (fossil soils) in Asia from Early Devonian deposits of Yunnan, China. Plant traces are extensive within the soil and occur as complex network-like structures, which are interpreted as representing long-lived, belowground rhizomes of the basal lycopsid Drepanophycus. The rhizomes produced large clones and helped the plant survive frequent sediment burial in well-drained soils within a seasonal wet\u2212dry climate zone. Rhizome networks contributed to the accumulation and pedogenesis of floodplain sediments and increased the soil stabilizing effects of early plants. Predating the appearance of trees with deep roots in the Middle Devonian, plant rhizomes have long functioned in the belowground soil ecosystem. This study presents strong, direct evidence for plant\u2212soil interactions at an early stage of vascular plant radiation. Soil stabilization by complex rhizome systems was apparently widespread, and contributed to landscape modification at an earlier time than had been appreciated.", "keyphrases": ["paleosol", "vascular plant", "terrestrial environment", "belowground rhizome"]}
{"id": "10.1130/G19527.1", "title": "Sea-level, humidity, and land-erosion records across the initial Eocene thermal maximum from a continental-marine transect in northern Spain", "abstract": "In two continental sections in the Tremp basin, northern Spain, the initial Eocene thermal maximum (also known as the Paleocene-Eocene thermal maximum) is registered by an \u223c6\u2030 fall in \u03b4 1 3 C values in soil carbonate nodules. High-resolution correlations, using the \u03b4 1 3 C excursion, can be made to nearby shelf and bathyal marine settings, allowing a detailed reconstruction of soil formation on land and transport of detritus to the sea during the initial Eocene thermal maximum. Soils that formed before and after the initial Eocene thermal maximum in the Tremp region reflect arid to semiarid conditions, with abundant evaporative minerals, whereas initial Eocene thermal maximum soils reflect seasonally wetter but generally dry conditions. During the initial Eocene thermal maximum, land erosion was intensified and accumulation rates of terrigenous detritus in the sea increased. This reflects both increased topographic relief associated with a prominent sea-level lowstand and enhanced seasonal precipitation over a dry landscape with sparse vegetation. Deeper erosion led to an increase in the flux of kaolinite from buried Mesozoic soils to the oceans. The association of the initial Eocene thermal maximum with a sea-level lowstand in northern Spain, as well as at other marginal North Atlantic sites, may reflect coeval large-scale magmatic activity in the northernmost Atlantic.", "keyphrases": ["eocene thermal maximum", "northern spain", "soil carbonate nodule"]}
{"id": "10.1029/2012PA002339", "title": "Vital effects in coccolith calcite: Cenozoic climate\u2010pCO2 drove the diversity of carbon acquisition strategies in coccolithophores?", "abstract": "[1]\u00a0Coccoliths, calcite plates produced by the marine phytoplankton coccolithophores, have previously shown a large array of carbon and oxygen stable isotope fractionations (termed \u201cvital effects\u201d), correlated to cell size and hypothesized to reflect the varying importance of active carbon acquisition strategies. Culture studies show a reduced range of vital effects between large and small coccolithophores under high CO2, consistent with previous observations of a smaller range of interspecific vital effects in Paleocene coccoliths. We present new fossil data examining coccolithophore vital effects over three key Cenozoic intervals reflecting changing climate and atmospheric partial pressure of CO2 (pCO2). Oxygen and carbon stable isotopes of size-separated coccolith fractions dominated by different species from well preserved Paleocene-Eocene thermal maximum (PETM, \u223c56 Ma) samples show reduced interspecific differences within the greenhouse boundary conditions of the PETM. Conversely, isotope data from the Plio-Pleistocene transition (PPT; 3.5\u20132\u00a0Ma) and the last glacial maximum (LGM; \u223c22 ka) show persistent vital effects of \u223c2\u2030. PPT and LGM data show a clear positive trend between coccolith (cell) size and isotopic enrichment in coccolith carbonate, as seen in laboratory cultures. On geological timescales, the degree of expression of vital effects in coccoliths appears to be insensitive topCO2 changes over the range \u223c350 ppm (Pliocene) to \u223c180 ppm (LGM). The modern array of coccolith vital effects arose after the PETM but before the late Pliocene and may reflect the operation of more diverse carbon acquisition strategies in coccolithophores in response to decreasing Cenozoic pCO2.", "keyphrases": ["carbon acquisition strategy", "coccolithophore", "vital effect"]}
{"id": "10.1144/jgs2013-015", "title": "An astronomical time scale for the Maastrichtian based on the Zumaia and Sopelana sections (Basque country, northern Spain)", "abstract": "The rhythmically bedded limestone\u2013marl alternations in the coastal cliffs of Sopelana and Zumaia in the Basque country, northern Spain, permit testing and refining of existing Maastrichtian chronologies (latest Cretaceous). The recently established astronomical time scale for the late Maastrichtian at Zumaia is extended into C31n with the integrated stratigraphy of the Sopelana section. The cyclic alternations of hemipelagic limestones and marls at Sopelana show a strong influence of eccentricity-modulated precession. Together, the Zumaia and Sopelana sections span almost the entire Maastrichtian, and encompass thirteen 405 kyr cycles spanning a total duration of 5.3 myr. From the Cretaceous\u2013Paleogene (K\u2013Pg) boundary downwards, 405 kyr minima in the lithological, magnetic susceptibility and reflectance data records are tuned to successive 405 kyr minima in the new La2011 eccentricity solution. Assuming a K\u2013Pg boundary age of 65.97 Ma, we present orbitally tuned ages of biostratigraphic and magnetostratigraphic events. Whereas the bases of Chrons C29r and C30n were reliably established at Zumaia and are in good agreement with previous studies, new data from Sopelana provide a refinement of the basal age of Chron C31r. Additional planktonic foraminifera and calcareous nannoplankton data from Zumaia, and new calcareous nannoplankton data from Sopelana, allow for worldwide correlation of the cyclostratigraphy of the Basque country. Supplementary materials: A geological map and additional data are available at www.geolsoc.org.uk/SUP18696.", "keyphrases": ["astronomical time scale", "maastrichtian", "northern spain"]}
{"id": "paleo.010355", "title": "Ontogenetic variation in the skull of Stenopterygius quadriscissus with an emphasis on prenatal development", "abstract": "The availability of a large sample size from a range of ontogenetic stages makes Stenopterygius quadriscissus a good model to study ontogenetic variation in a fossil sauropsid. We qualitatively examined pre- and postnatal ontogenetic changes in the cranium of S. quadriscissus. The prenatal ossification sequence is similar to other diapsids, exhibiting delayed chondrocranial ossification compared to the dermatocranium. In the dermatocranium, the circumorbital area is more ossified earlier in development relative to other elements, especially those of the skull roof where ossification is comparatively weaker across prenatal stages. Perinatally all cranial elements are ossified, and many scarf and step joints are already closed. We propose four prenatal and three postnatal stages in S. quadriscissus on the basis of relative ossification, size and qualitative cranial characters pertaining to the jugal, parietal, frontal, pterygoid and surangular. These will provide a basis for determining ontogenetic stages in other ichthyosaurs. Moreover, our postnatal observations aid in refining ontogenetic characters for phylogenetic studies. Lastly, we observed that the antimeric sutures of the midline of the skull roof are open perinatally and that fusion of the midline only appears in the adult stage. We hypothesize that the loose connection of the midline functions as a fontanelle, limiting potential damage during birth.", "keyphrases": ["stenopterygius quadriscissus", "prenatal development", "ossification", "birth", "ontogenetic variation"]}
{"id": "10.2307/3514691", "title": "Taphonomy of a modern shrimp: implications for the arthropod fossil record", "abstract": "Every living organism represents a potentialfossil, although only a few are ever successfully fossilized. Taphonomic studies should explain episodes of both fossilization and of non-fossilization. This paper examines some of the taphonomic variables that may bias the arthropod fossil record. The short-term preservation potential of the modern carid shrimp, Pandalus danae, was studied in a variety of laboratory and field settings. Freshly killed specimens were buried at two intertidal localities on San Juan Island, Puget Sound, Washington. Carcasses were buried at depths of 5-20 cm for periods of one day to three weeks. Destruction by scavengers (crabs?) was the probable primary cause of carcass destruction. Further breakdown was caused by bacterial decomposition and disturbance by burrowing infauna. Shrimp remains were placed in a series of glass jars in the laboratory. Jars differed in the presence and kind of enclosed sediment and in the degree of aeration. Decomposition destroyed nearly all soft tissues within a period of two weeks. The cuticle became extremely soft, resulting in loss of physical integrity of the remains. Differences between oxic and anoxic decomposition were minor. These results, along with a consideration of the biological, physical, and chemical effects of bioturbation, suggest that disturbance by scavengers or burrowing infauna is a majorfactor in the destruction of buried arthropod remains. The absence or inhibition of bioturbation may be a necessary condition for arthropod preservation. The preservation potential of arthropods, and of other soft-bodied forms, may have declined since the Paleozoic.", "keyphrases": ["shrimp", "arthropod fossil record", "cuticle"]}
{"id": "paleo.004415", "title": "Probabilistic divergence time estimation without branch lengths: dating the origins of dinosaurs, avian flight and crown birds", "abstract": "Branch lengths\u2014measured in character changes\u2014are an essential requirement of clock-based divergence estimation, regardless of whether the fossil calibrations used represent nodes or tips. However, a separate set of divergence time approaches are typically used to date palaeontological trees, which may lack such branch lengths. Among these methods, sophisticated probabilistic approaches have recently emerged, in contrast with simpler algorithms relying on minimum node ages. Here, using a novel phylogenetic hypothesis for Mesozoic dinosaurs, we apply two such approaches to estimate divergence times for: (i) Dinosauria, (ii) Avialae (the earliest birds) and (iii) Neornithes (crown birds). We find: (i) the plausibility of a Permian origin for dinosaurs to be dependent on whether Nyasasaurus is the oldest dinosaur, (ii) a Middle to Late Jurassic origin of avian flight regardless of whether Archaeopteryx or Aurornis is considered the first bird and (iii) a Late Cretaceous origin for Neornithes that is broadly congruent with other node- and tip-dating estimates. Demonstrating the feasibility of probabilistic time-scaling further opens up divergence estimation to the rich histories of extinct biodiversity in the fossil record, even in the absence of detailed character data.", "keyphrases": ["branch length", "avian flight", "crown bird", "node"]}
{"id": "10.1073/pnas.1620754114", "title": "Fossil and genomic evidence constrains the timing of bison arrival in North America", "abstract": "Significance The appearance of bison in North America is both ecologically and paleontologically significant. We analyzed mitochondrial DNA from the oldest known North American bison fossils to reveal that bison were present in northern North America by 195\u2013135 thousand y ago, having entered from Asia via the Bering Land Bridge. After their arrival, bison quickly colonized much of the rest of the continent, where they rapidly diversified phenotypically, producing, for example, the giant long-horned morphotype Bison latifrons during the last interglaciation. The arrival of bison in North America marks one of the most successful large-mammal dispersals from Asia within the last million years, yet the timing and nature of this event remain poorly determined. Here, we used a combined paleontological and paleogenomic approach to provide a robust timeline for the entry and subsequent evolution of bison within North America. We characterized two fossil-rich localities in Canada\u2019s Yukon and identified the oldest well-constrained bison fossil in North America, a 130,000-y-old steppe bison, Bison cf. priscus. We extracted and sequenced mitochondrial genomes from both this bison and from the remains of a recently discovered, \u223c120,000-y-old giant long-horned bison, Bison latifrons, from Snowmass, Colorado. We analyzed these and 44 other bison mitogenomes with ages that span the Late Pleistocene, and identified two waves of bison dispersal into North America from Asia, the earliest of which occurred \u223c195\u2013135 thousand y ago and preceded the morphological diversification of North American bison, and the second of which occurred during the Late Pleistocene, \u223c45\u201321 thousand y ago. This chronological arc establishes that bison first entered North America during the sea level lowstand accompanying marine isotope stage 6, rejecting earlier records of bison in North America. After their invasion, bison rapidly colonized North America during the last interglaciation, spreading from Alaska through continental North America; they have been continuously resident since then.", "keyphrases": ["north america", "steppe bison", "bison dispersal", "morphological diversification"]}
{"id": "paleo.010260", "title": "Homo naledi and Pleistocene hominin evolution in subequatorial Africa", "abstract": "New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in Africa. Direct dating of Homo naledi fossils from the Dinaledi Chamber (Berger et al., 2015) shows that they were deposited between about 236 ka and 335 ka (Dirks et al., 2017), placing H. naledi in the later Middle Pleistocene. Hawks and colleagues (Hawks et al., 2017) report the discovery of a second chamber within the Rising Star system (Dirks et al., 2015) that contains H. naledi remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least H. naledi representing a survivor from the earliest stages of diversification within Homo. The existence of a diverse array of hominins in subequatorial comports with our present knowledge of diversity across other savanna-adapted species, as well as with palaeoclimate and paleoenvironmental data. H. naledi casts the fossil and archaeological records into a new light, as we cannot exclude that this lineage was responsible for the production of Acheulean or Middle Stone Age tool industries. DOI: http://dx.doi.org/10.7554/eLife.24234.001", "keyphrases": ["pleistocene", "subequatorial africa", "homo"]}
{"id": "10.7554/eLife.24234", "title": "Homo naledi and Pleistocene hominin evolution in subequatorial Africa", "abstract": "New discoveries and dating of fossil remains from the Rising Star cave system, Cradle of Humankind, South Africa, have strong implications for our understanding of Pleistocene human evolution in Africa. Direct dating of Homo naledi fossils from the Dinaledi Chamber (Berger et al., 2015) shows that they were deposited between about 236 ka and 335 ka (Dirks et al., 2017), placing H. naledi in the later Middle Pleistocene. Hawks and colleagues (Hawks et al., 2017) report the discovery of a second chamber within the Rising Star system (Dirks et al., 2015) that contains H. naledi remains. Previously, only large-brained modern humans or their close relatives had been demonstrated to exist at this late time in Africa, but the fossil evidence for any hominins in subequatorial Africa was very sparse. It is now evident that a diversity of hominin lineages existed in this region, with some divergent lineages contributing DNA to living humans and at least H. naledi representing a survivor from the earliest stages of diversification within Homo. The existence of a diverse array of hominins in subequatorial comports with our present knowledge of diversity across other savanna-adapted species, as well as with palaeoclimate and paleoenvironmental data. H. naledi casts the fossil and archaeological records into a new light, as we cannot exclude that this lineage was responsible for the production of Acheulean or Middle Stone Age tool industries. DOI: http://dx.doi.org/10.7554/eLife.24234.001", "keyphrases": ["pleistocene", "subequatorial africa", "homo"]}
{"id": "paleo.008626", "title": "High niche diversity in Mesozoic pollinating lacewings", "abstract": "Niche diversity of pollinating insects plays a vital role in maintaining extant terrestrial ecosystems. A key dimension of pollination niches refers to the insect proboscis length that commonly matches the floral tube length. Here we describe new kalligrammatid lacewings (an iconic Mesozoic pollinating insect lineage) from late Cretaceous Burmese amber and Mesozoic sediments in China. Kalligrammatids display complex configurations of elongate mouthpart elements consisting of well-developed maxillae, labium and their palps. The mouthpart lengths vary among species, from 0.6 to 18.0 mm, suggesting corresponding variability in the floral tube lengths of Mesozoic plants. With the diversification of pollinating habits, the kalligrammatids presented highly divergent traits related to chemical communication and defence mechanisms. Together with other Mesozoic long-proboscid insects, these fossils not only reveal the high niche diversity of Mesozoic pollinating insects but also highlight the diversity of Mesozoic pollinator-dependent plants prior to the rise of angiosperms.", "keyphrases": ["mesozoic", "lacewing", "high niche diversity"]}
{"id": "10.1080/02724634.2020.1781142", "title": "Hitchcock's Leptodactyli, Penetrative Tracks, and Dinosaur Footprint Diversity", "abstract": "ABSTRACT Starting with his first report on fossil footprints from the Connecticut Valley over 180 years ago, Edward Hitchcock described what he interpreted as a burgeoning ancient fauna founded on ever-increasing nominal track diversity. For three decades, Hitchcock made countless contributions to ichnology, but his inference of thin-toed animals (Leptodactyli) from thin-toed tracks is flawed by modern criteria. Leptodactylous tracks are now recognized as variants made by thick-toed feet penetrating into soft, collapsing substrates. Herein, we take a closer look at the creation of such penetrative tracks using computer simulations of particle flow. Classic specimens are used to demonstrate how different modes of surface presentation make penetrative tracks challenging to recognize and interpret. Evaluation of 266 specimens from 43 leptodactylous ichnotaxa reveals that \u223c90% are penetrative. We propose that a reliance on a single formation mechanism confounded Hitchcock's ability to reliably recognize different trackmakers. This is not an old problem applicable only to fossils collected long ago; domination of a transmission-based model continues to bias the field today. Most texts and many publications either omit collapsed penetrative tracks or fail to recognize them as a significant source of variation. Without proper regard for subsurface toe movement and sediment flow, inferences of foot shape from track shape can, as for Hitchcock, be led far astray. The misidentification and misunderstanding of penetrative tracks impact our conception of the diversity of life in the Early Jurassic, as well as in other ichnofaunas worldwide.", "keyphrases": ["leptodactyli", "penetrative track", "hitchcock"]}
{"id": "paleo.012835", "title": "The Impact of the Rate Prior on Bayesian Estimation of Divergence Times with Multiple Loci", "abstract": "Bayesian methods provide a powerful way to estimate species divergence times by combining information from molecular sequences with information from the fossil record. With the explosive increase of genomic data, divergence time estimation increasingly uses data of multiple loci (genes or site partitions). Widely used computer programs to estimate divergence times use independent and identically distributed (i.i.d.) priors on the substitution rates for different loci. The i.i.d. prior is problematic. As the number of loci (L) increases, the prior variance of the average rate across all loci goes to zero at the rate 1/L. As a consequence, the rate prior dominates posterior time estimates when many loci are analyzed, and if the rate prior is misspecified, the estimated divergence times will converge to wrong values with very narrow credibility intervals. Here we develop a new prior on the locus rates based on the Dirichlet distribution that corrects the problematic behavior of the i.i.d. prior. We use computer simulation and real data analysis to highlight the differences between the old and new priors. For a dataset for six primate species, we show that with the old i.i.d. prior, if the prior rate is too high (or too low), the estimated divergence times are too young (or too old), outside the bounds imposed by the fossil calibrations. In contrast, with the new Dirichlet prior, posterior time estimates are insensitive to the rate prior and are compatible with the fossil calibrations. We re-analyzed a phylogenomic data set of 36 mammal species and show that using many fossil calibrations can alleviate the adverse impact of a misspecified rate prior to some extent. We recommend the use of the new Dirichlet prior in Bayesian divergence time estimation. [Bayesian inference, divergence time, relaxed clock, rate prior, partition analysis.]", "keyphrases": ["multiple loci", "average rate", "dirichlet distribution"]}
{"id": "paleo.003920", "title": "Environmentally driven extinction and opportunistic origination explain fern diversification patterns", "abstract": "Combining palaeontological and neontological data offers a unique opportunity to investigate the relative roles of biotic and abiotic controls of species diversification, and the importance of origination versus extinction in driving evolutionary dynamics. Ferns comprise a major terrestrial plant radiation with an extensive evolutionary history providing a wealth of modern and fossil data for modelling environmental drivers of diversification. Here we develop a novel Bayesian model to simultaneously estimate correlations between diversification dynamics and multiple environmental trajectories. We estimate the impact of different factors on fern diversification over the past 400 million years by analysing a comprehensive dataset of fossil occurrences and complement these findings by analysing a large molecular phylogeny. We show that origination and extinction rates are governed by fundamentally different processes: originations depend on within-group diversity but are largely unaffected by environmental changes, whereas extinctions are strongly affected by external factors such as climate and geology. Our results indicate that the prime driver of fern diversity dynamics is environmentally driven extinction, with origination being an opportunistic response to diminishing ecospace occupancy.\nThe world's biodiversity is the result of a complex interplay between biotic and abiotic drivers and their changes over time and space 1, 2 . Recent advances in paleontology and molecular phylogenetics have led to a renaissance in macroevolutionary research, but inherent biases in the fossil record and phylogenetic data often compromise inferences based on a single type of data 3 . Hence, the relative roles of different factors affecting species diversification, as well as the importance of origination versus extinction, remain contested 1-3 . Ferns are an unusually well-suited group to investigate these questions because of their high diversity throughout most of the history of terrestrial life 4, 5 , their rich fossil record [4] [5] [6] , and the well understood phylogenetic relationships among their extant members [7] [8] [9] [10] [11] .\nEarlier, ferns were seen as a relict group with their heyday in the Palaeozoic and diminished importance towards the present, as they were gradually replaced by gymnosperms and angiosperms 4 . This view was challenged by molecular phylogenies revealing that the most diverse, predominantly epiphytic fern lineages diversified simultaneously with the angiosperms 12 . This has been taken as evidence for adaptive radiation of epiphytic ferns in angiosperm-dominated forests 12, 13 . Although these alternative views suggest contrasting interactions between ferns and angiosperms, they emphasize the importance of biotic factors in driving diversification as predicted by the \"Red Queen\" model of evolution 1, 14 . Other studies have linked fern diversification with the physical environment, by suggesting that warm and wet climates induced the simultaneous radiation of angiosperms and", "keyphrases": ["origination", "extinction rate", "environmental change"]}
{"id": "paleo.005043", "title": "Tropical ancient DNA reveals relationships of the extinct Bahamian giant tortoise Chelonoidis alburyorum", "abstract": "Ancient DNA of extinct species from the Pleistocene and Holocene has provided valuable evolutionary insights. However, these are largely restricted to mammals and high latitudes because DNA preservation in warm climates is typically poor. In the tropics and subtropics, non-avian reptiles constitute a significant part of the fauna and little is known about the genetics of the many extinct reptiles from tropical islands. We have reconstructed the near-complete mitochondrial genome of an extinct giant tortoise from the Bahamas (Chelonoidis alburyorum) using an approximately 1 000-year-old humerus from a water-filled sinkhole (blue hole) on Great Abaco Island. Phylogenetic and molecular clock analyses place this extinct species as closely related to Gal\u00e1pagos (C. niger complex) and Chaco tortoises (C. chilensis), and provide evidence for repeated overseas dispersal in this tortoise group. The ancestors of extant Chelonoidis species arrived in South America from Africa only after the opening of the Atlantic Ocean and dispersed from there to the Caribbean and the Gal\u00e1pagos Islands. Our results also suggest that the anoxic, thermally buffered environment of blue holes may enhance DNA preservation, and thus are opening a window for better understanding evolution and population history of extinct tropical species, which would likely still exist without human impact.", "keyphrases": ["ancient dna", "chelonoidis alburyorum", "extinct specie", "mitochondrial genome", "bahamas"]}
{"id": "paleo.006326", "title": "New Fossil Remains from the Pliocene Koetoi Formation of Northern Japan Provide Insights Into Growth Rates and the Vertebral Evolution of Porpoises", "abstract": "Extant porpoises (Phocoenidae) are odontocetes characterized by their small size, short and wide rostrum, late (or absent) completion of epiphyseal ankylosis in the vertebral column (= physical maturity), and short life cycles, all of which are thought to have resulted from progenetic evolution. We describe a small fossil phocoenid from the lower Pliocene Koetoi Formation of Hokkaido (northern Japan), preserving a small, narrow rostrum, as well as anteroposteriorly elongate thoracic and lumbar vertebral centra with completely fused epiphyses. Physical maturity in this specimen occurred significantly earlier than in extant phocoenids, as shown by dental data indicating that the specimen died at only four years of age. The difference between the present material and extant porpoises may be attributable to different growth rates during ontogeny. The long centra and caudally inclined neural spines of the specimen from Hokkaido are primitive characters among phocoenids. By contrast, the great height of its neural spines is highly derived, even among extant species, and suggestive of a fast swimmer. In terms of its vertebral morphology, the new specimen falls within a morphological continuum defined by the archaic Numataphocoena yamashitai and the highly derived vertebral morphology of Phocoenoides dalli. Phocoenid vertebral evolution has been complex and frequently convergent, as opposed to stepwise and unidirectional. The different vertebral morphologies of the new specimen and the contemporaneous extinct taxa Numataphocoena and Piscolithax longirostris indicate that they were adapted to different environments.", "keyphrases": ["pliocene koetoi formation", "northern japan", "vertebral evolution"]}
{"id": "10.1666/09018.1", "title": "Carcasses on the coastline: measuring the ecological fidelity of the cetacean stranding record in the eastern North Pacific Ocean", "abstract": "Abstract To understand how well fossil assemblages represent original communities, paleoecologists seek comparisons between death assemblages and their source communities. These comparisons have traditionally used nearshore, marine invertebrate assemblages for their logistical ease, high abundance, and comparable census data from living communities. For large marine vertebrates, like cetaceans, measuring their diversity in ocean ecosystems is difficult and expensive. Cetaceans, however, often beach or strand themselves along the coast, and archived data on stranded cetaceans have been recorded, in some areas, over several decades. If the stranding record is interpreted as a death assemblage, then the stranding record may represent a viable alternative for measuring diversity in living communities on directly adjacent coastlines. This study assessed the fidelity of the cetacean stranding record in the eastern North Pacific Ocean. The living community in this region has been studied for over 100 years and, recently, extensive and systematic live transect surveys using ship-based observing platforms have produced a valuable source of live diversity data. Over this same period, the U.S. Marine Mammal Stranding Program has collected and archived a record of cetacean strandings along the U.S. Pacific coastline, providing an ideal death assemblage for comparison. Using fidelity metrics commonly used in marine invertebrate taphonomy, I determined that the stranding record samples the living cetacean community with high fidelity, across fine and coarse taxonomic ranks, and at large geographic scales (>1000 km of coastline). The stranding record is also richer than the live surveys, with live-dead ratios between 1.1 and 1.3. The stranding record recovers similar rank-order relative abundances as live surveys, with statistical significance. Also, I applied sample-based rarefaction methods to generate collector's curves for strandings along the U.S. Pacific Coast to better evaluate the spatiotemporal characteristics of the stranding record. Results indicate that saturation (i.e., sampling >95% assemblage) at species, genus, and family levels occurs in less than five years of sampling, with families accumulating faster than species, and larger geographic regions (i.e., longer coastlines) accumulating taxa the most rapidly. The high fidelity of the stranding record, measured both in richness and by ranked relative abundance, implies that ecological structure from living cetacean communities is recorded in the death assemblage, a finding that parallels marine invertebrate assemblages, though at far larger spatial scales. These results have implications for studying cetacean ecology in both modern and ancient environments: first, these results imply that the stranding record, over sufficiently long time intervals, yields a richer assemblage than using line-transect methods, and faithfully records aspects of community structure; and second, these results imply that geochronologically well-constrained fossil cetacean assemblages might preserve ecologically relevant features of community structure, depending on depositional and taphonomic conditions.", "keyphrases": ["coastline", "cetacean stranding record", "north pacific ocean", "death assemblage"]}
{"id": "paleo.009381", "title": "Fire and brief human occupations in Iberia during MIS 4: Evidence from Abric del Pastor (Alcoy, Spain)", "abstract": "There is a relatively low amount of Middle Paleolithic sites in Europe dating to MIS 4. Of the few that exist, several of them lack evidence for anthropogenic fire, raising the question of how this period of global cooling may have affected the Neanderthal population. The Iberian Peninsula is a key area to explore this issue, as it has been considered as a glacial refugium during critical periods of the Neanderthal timeline and might therefore yield archaeological contexts in which we can explore possible changes in the behaviour and settlement patterns of Neanderthal groups during MIS 4. Here we report recent data from Abric del Pastor, a small rock shelter in Alcoy (Alicante, Spain) with a stratified deposit containing Middle Palaeolithic remains. We present absolute dates that frame the sequence within MIS 4 and multi-proxy geoarchaeological evidence of in situ anthropogenic fire, including microscopic evidence of in situ combustion residues and thermally altered sediment. We also present archaeostratigraphic evidence of recurrent, functionally diverse, brief human occupation of the rock shelter. Our results suggest that Neanderthals occupied the Central Mediterranean coast of the Iberian Peninsula during MIS 4, that these Neanderthals were not undergoing climatic stress and they were habitual fire users.", "keyphrases": ["human occupation", "abric del pastor", "fire"]}
{"id": "10.1126/science.aao2200", "title": "Environmental dynamics during the onset of the Middle Stone Age in eastern Africa", "abstract": "The Middle Stone Age in Africa The Olorgesailie basin in the southern Kenya rift valley contains sediments dating back to 1.2 million years ago, preserving a long archaeological record of human activity and environmental conditions. Three papers present the oldest East African evidence of the Middle Stone Age (MSA) and elucidate the system of technology and behavior associated with the origin of Homo sapiens. Potts et al. present evidence for the demise of Acheulean technology that preceded the MSA and describe variations in late Acheulean hominin behavior that anticipate MSA characteristics. The transition to the MSA was accompanied by turnover of large mammals and large-scale landscape change. Brooks et al. establish that \u223c320,000 to 305,000 years ago, the populations in eastern Africa underwent a technological shift upon procurement of distantly sourced obsidian for toolmaking, indicating the early development of social exchange. Deino et al. provide the chronological underpinning for these discoveries. Science, this issue p. 86, p. 90, p. 95 Changes in fauna, landscapes, and climate were associated with novel adaptive behaviors in the earliest Homo sapiens. Development of the African Middle Stone Age (MSA) before 300,000 years ago raises the question of how environmental change influenced the evolution of behaviors characteristic of early Homo sapiens. We used temporally well-constrained sedimentological and paleoenvironmental data to investigate environmental dynamics before and after the appearance of the early MSA in the Olorgesailie basin, Kenya. In contrast to the Acheulean archeological record in the same basin, MSA sites are associated with a markedly different faunal community, more pronounced erosion-deposition cycles, tectonic activity, and enhanced wet-dry variability. Aspects of Acheulean technology in this region imply that, as early as 615,000 years ago, greater stone material selectivity and wider resource procurement coincided with an increased pace of land-lake fluctuation, potentially anticipating the adaptability of MSA hominins.", "keyphrases": ["middle stone age", "eastern africa", "environmental dynamic"]}
{"id": "paleo.006243", "title": "Evenness and diversity in Upper Cambrian \u2013 Lower Ordovician trilobite communities from the Central Andean Basin (Cordillera Oriental, Argentina)", "abstract": "Community evenness has recently received much attention, either because it is related to ecosystem functioning or because it may affect estimation of diversity. Temporal and environmental trends in diversity and evenness of trilobite communities during the Late Cambrian \u2013 Early Ordovician of the Cordillera Oriental (north\u2010western Argentina) are here analysed. Richness and evenness increase through time in both deep subtidal (between fair\u2010weather and storm wave base) and offshore (below storm wave base) communities. Two significant patterns are superimposed on this general trend: (1) the magnitude of the increase in evenness is much more pronounced in deep than in shallower settings, and (2) richness and evenness trajectories are decoupled (while a significant rise in evenness is recorded in the middle Tremadocian (Tr2), an increase in richness is delayed until the late Tremadocian (Tr3)). In contrast to expectations, a single family (Olenidae) is dominant in samples associated with this earlier rise in evenness relative to richness. Hence, this trend is explained neither by the number of families present in the communities nor by the familial identity of the most abundant taxon. Large\u2010scale comparisons of the timing and geographical components of these trends are restricted to the patterns recognized in Laurentian North American studies. Results from the Cordillera Oriental mirror those of Laurentia regarding the rise in both metrics in deep marine settings. Nevertheless, the timing of this increase in richness and evenness is delayed in the Cordillera Oriental, supporting the idea that palaeogeographical regions differed in the nature and timing of ecological changes. Finally, the rise in trilobite alpha\u2010diversity through the Late Cambrian \u2013 Early Ordovician of the Cordillera Oriental supports the idea that trilobite alpha\u2010diversity did not decline worldwide, suggesting that the relative decline in trilobite alpha\u2010diversity is most probably caused by the dilution effect.", "keyphrases": ["trilobite community", "cordillera oriental", "evenness"]}
{"id": "paleo.005350", "title": "New data from Oman indicate benthic high biomass productivity coupled with low taxonomic diversity in the aftermath of the Permian\u2013Triassic Boundary mass extinction", "abstract": "A new Early Triassic marine fauna is described from an exotic block (olistolith) from the Ad Daffah conglomerate in eastern Oman (Batain), which provides new insights into the ecology and diversity during the early aftermath of the Permian\u2013Triassic Boundary mass extinction. Based on conodont quantitative biochronology, we assign a middle Griesbachian age to the upper part of this boulder. It was derived from an offshore seamount and yielded both nektonic and benthic faunas, including conodonts, ammonoids, gastropods and crinoid ossicles in mass abundance. This demonstrates that despite the stratigraphically near extinction at the Permian\u2013Triassic Boundary, Crinoidea produced enough biomass to form crinoidal limestone as early as middle Griesbachian time. Baudicrinus, previously placed in Dadocrinidae, is now placed in Holocrinidae; therefore, Dadocrinidae are absent in the Early Triassic, and Holocrinidae remains the most basal crown-group articulates, originating during the middle Griesbachian in the Tethyan Realm. Abundant gastropods assigned to Naticopsis reached a shell size larger than 20\u00a0mm and provide another example against any generalized Lilliput effect during the Griesbachian. Whereas the benthic biomass was as high as to allow the resumption of small carbonate factories, the taxonomic diversity of the benthos remained low compared to post-Early Triassic times. This slow benthic taxonomic recovery is here attributed to low competition within impoverished post-extinction faunas.", "keyphrases": ["oman", "taxonomic diversity", "aftermath", "early triassic", "griesbachian"]}
{"id": "paleo.001986", "title": "The fragmentation of Pangaea and Mesozoic terrestrial vertebrate biodiversity", "abstract": "During the Mesozoic (242\u201366 million years ago), terrestrial regions underwent a massive shift in their size, position and connectivity. At the beginning of the era, the land masses were joined into a single supercontinent called Pangaea. However, by the end of the Mesozoic, terrestrial regions had become highly fragmented, both owing to the drifting apart of the continental plates and the extremely high sea levels that flooded and divided many regions. How terrestrial biodiversity was affected by this fragmentation and large-scale flooding of the Earth's landmasses is uncertain. Based on a model using the species\u2013area relationship (SAR), terrestrial vertebrate biodiversity would be expected to nearly double through the Mesozoic owing to continental fragmentation, despite a decrease of 24% in total terrestrial area. Previous studies of Mesozoic vertebrates have generally found increases in terrestrial diversity towards the end of the era, although these increases are often attributed to intrinsic or climatic factors. Instead, continental fragmentation over this time may largely explain any observed increase in terrestrial biodiversity. This study demonstrates the importance that non-intrinsic effects can have on the taxonomic success of a group, and the importance of geography to understanding past biodiversity.", "keyphrases": ["pangaea", "mesozoic", "terrestrial vertebrate biodiversity", "landmass"]}
{"id": "10.1111/joa.13359", "title": "Effect of mass and habitat on the shape of limb long bones: A morpho\u2010functional investigation on Bovidae (Mammalia: Cetartiodactyla)", "abstract": "Limb long bones are essential to an animal's locomotion, and are thus expected to be heavily influenced by factors such as mass or habitat. Because they are often the only organs preserved in the fossil record, understanding their adaptive trends is key to reconstructing the paleobiology of fossil taxa. In this regard, the Bovidae has always been a prized group of study. This family is extremely diverse in terms of both mass and habitat, and it is expected that their bones will possess adaptations to both factors. Here, we present the first 3D geometric morphometric study focusing on bovid limb long bones. We used anatomical landmarks as well as curve and surface sliding semi\u2010landmarks to accurately describe the stylopod and zeugopod bones. We included 50 species from ten of the twelve currently recognized tribes of bovids, ranging from 4.6 to 725 kg, and living in open plains, forests, mountains, or anywhere in\u2010between. Shape data were correlated with the mean mass of the species and its habitat, even when taking into account the phylogenetic history of our sample. Bones pertaining to heavy species are more robust, adapted for a better repartition of stronger forces. Articulations are especially affected, being proportionally much larger in heavier species. Muscle insertion areas are unevenly affected. Insertion areas of muscles implied in body support and propulsion show a strong increase in their robustness when compared to insertion areas of muscles acting on the limb mostly when it is off the ground. Habitat influences the shape of the humerus, the radius\u2010ulna, and the femur, but not of the tibia, whether the phylogeny is taken into account or not. Specific habitats tend to be associated with particular features on the bones. Articulations are proportionally wider in open\u2010habitat species, and the insertion areas of muscles involved in limb extension and propulsion are wider, reflecting the fact that open habitat species are more cursorial and rely on fast running to avoid predators. Forest and mountain species generally present similar adaptations for increased manoeuvrability, such as a round femoral head, and generally have more gracile bones.", "keyphrases": ["mass", "long bone", "bovidae"]}
{"id": "10.1002/evan.20324", "title": "Finding fossils in new ways: An artificial neural network approach to predicting the location of productive fossil localities", "abstract": "Chance and serendipity have long played a role in the location of productive fossil localities by vertebrate paleontologists and paleoanthropologists. We offer an alternative approach, informed by methods borrowed from the geographic information sciences and using recent advances in computer science, to more efficiently predict where fossil localities might be found. Our model uses an artificial neural network (ANN) that is trained to recognize the spectral characteristics of known productive localities and other land cover classes, such as forest, wetlands, and scrubland, within a study area based on the analysis of remotely sensed (RS) imagery. Using these spectral signatures, the model then classifies other pixels throughout the study area. The results of the neural network classification can be examined and further manipulated within a geographic information systems (GIS) software package. While we have developed and tested this model on fossil mammal localities in deposits of Paleocene and Eocene age in the Great Divide Basin of southwestern Wyoming, a similar analytical approach can be easily applied to fossil\u2010bearing sedimentary deposits of any age in any part of the world. We suggest that new analytical tools and methods of the geographic sciences, including remote sensing and geographic information systems, are poised to greatly enrich paleoanthropological investigations, and that these new methods should be embraced by field workers in the search for, and geospatial analysis of, fossil primates and hominins. \u00a9 2011 Wiley\u2010Liss, Inc.", "keyphrases": ["location", "productive fossil locality", "remote sensing"]}
{"id": "paleo.002807", "title": "The terrestrial biota prior to the origin of land plants (embryophytes): a review of the evidence", "abstract": "It is often assumed that life originated and diversified in the oceans prior to colonizing the land. However, environmental constraints in chemical evolution models point towards critical steps leading to the origin of life as having occurred in subaerial settings. The earliest fossil record does not include finds from terrestrial deposits, so much of our understanding about the presence of a terrestrial microbial cover prior to the Proterozoic is based on inference and geochemical proxies that indicate biospheric carbon cycling during the Archaean. Our assessment is that by 2.7 Ga, microbial ecosystems in terrestrial settings were driven by oxygen\u2010generating, photosynthetic cyanobacteria. Studies of modern organisms indicate that both the origin and primary diversification of the eukaryotes could have occurred in terrestrial settings, shortly after 2.0 Ga, but there is no direct fossil evidence of terrestrial eukaryotes until about 1.1 Ga. At this time, it appears that the diversity of life in non\u2010marine habitats exceeded that found in marine settings where sulphidic seas may have impaired eukaryotic physiology and retarded evolution. Geochemical proxies indicate the establishment of an extensive soil\u2010forming microbial cover by 850 Ma, and it is possible that a rise in atmospheric oxygen at this time was due to the evolutionary expansion of green algae into terrestrial habitats. Direct fossil evidence of the earliest terrestrial biotas in the Phanerozoic consists of problematical palynomorphs from the Cambro\u2010Ordovician of Laurentia. These indicate that the evolution of the first land plants (embryophytes) during the Middle Ordovician took place within a landscape that included aeroterrestrial algae which were actively adapting to selection in subaerial settings.", "keyphrases": ["terrestrial biota", "embryophyte", "algae"]}
{"id": "10.1002/spp2.1355", "title": "An early\u2010diverging procolophonid from the lowermost Triassic of South America and the origins of herbivory in Procolophonoidea", "abstract": "Procolophonoidea was the only parareptile clade to survive the end\u2010Permian mass extinction, and they experienced a major adaptive radiation during the Triassic. The flourishing of procolophonoid lineages in highly stressful post\u2010extinction environments may be, at least in part, a result of their early adaptations to herbivory, which would eventually become the most common feeding strategy in later representatives of the group. Although procolophonoids are comparatively diverse in the South African Lystrosaurus declivis Assemblage Zone, only the Gondwanan widespread taxon Procolophon trigoniceps has been thus far reported in South American deposits of similar age. Here, we present a new procolophonid genus and species from the Lower Triassic Sanga do Cabral Formation of Brazil. Oryporan insolitus gen. et sp. nov. combines typical adaptations suggestive of herbivory with primitive character states that are peculiar to early procolophonoids. Accordingly, phylogenetic analysis places the new species as an early\u2010diverging procolophonid, thus far the phylogenetically earliest to develop apparent adaptations for herbivory. Character optimization shows that the bulbous, labiolingually expanded molariforms of most procolophonids (usually interpreted as indicative of high\u2010fibre herbivory) were co\u2010opted from an insectivorous dentition. The new taxon also highlights the diversity of feeding habits displayed by Early Triassic procolophonoids, which was probably crucial for the survival of the clade in post\u2010extinction disaster communities.", "keyphrases": ["procolophonid", "herbivory", "procolophonoidea", "phylogenetic analysis"]}
{"id": "paleo.006926", "title": "Uncertain-tree: discriminating among competing approaches to the phylogenetic analysis of phenotype data", "abstract": "Morphological data provide the only means of classifying the majority of life's history, but the choice between competing phylogenetic methods for the analysis of morphology is unclear. Traditionally, parsimony methods have been favoured but recent studies have shown that these approaches are less accurate than the Bayesian implementation of the Mk model. Here we expand on these findings in several ways: we assess the impact of tree shape and maximum-likelihood estimation using the Mk model, as well as analysing data composed of both binary and multistate characters. We find that all methods struggle to correctly resolve deep clades within asymmetric trees, and when analysing small character matrices. The Bayesian Mk model is the most accurate method for estimating topology, but with lower resolution than other methods. Equal weights parsimony is more accurate than implied weights parsimony, and maximum-likelihood estimation using the Mk model is the least accurate method. We conclude that the Bayesian implementation of the Mk model should be the default method for phylogenetic estimation from phenotype datasets, and we explore the implications of our simulations in reanalysing several empirical morphological character matrices. A consequence of our finding is that high levels of resolution or the ability to classify species or groups with much confidence should not be expected when using small datasets. It is now necessary to depart from the traditional parsimony paradigms of constructing character matrices, towards datasets constructed explicitly for Bayesian methods.", "keyphrases": ["morphological data", "phylogenetic method", "bayesian implementation", "simulation"]}
{"id": "10.1139/e02-081", "title": "\u201cWithout a leg to stand on\u201d: on the evolution and development of axial elongation and limblessness in tetrapods", "abstract": "A review of the osteology of the axial and appendicular skeleton of fossil and extant tetrapods, in the context of tetrapod phylogenetic patterns, reveals common patterns of limb loss and axial elongation. A threshold number of 35\u201340 presacral vertebrae is linked to minor reductions in digit number and the phalangeal count. Presacral vertebral counts do not increase gradually, rather, presacral counts jump from 35\u201340 to 60\u201370. At this point, limb loss is extreme, with forelimbs being reduced to tiny appendages or lost altogether. Higher presacral counts (>90) are linked to total forelimb loss and radical rear-limb reductions culminating in total loss. A pattern of this sort is recognized in Paleozoic lepospondyls and Mesozoic to modern squamates. Developmental genetic models illuminate gene systems that are associated with morphogenesis and are linked to the evolution of limb reduction and leglessness in these tetrapods.", "keyphrases": ["axial elongation", "tetrapod", "vertebrae"]}
{"id": "10.1029/2004PA001094", "title": "Orbitally paced paleoproductivity variations in the Timor Sea and Indonesian Throughflow variability during the last 460 kyr", "abstract": "[1]\u00a0A high-resolution (\u223c1\u20132 kyr) multiproxy record from the Timor Sea in the easternmost Indian Ocean (International Marine Global Change (IMAGES) Program Core MD01-2378, latitude 13\u00b004.95\u2032S, longitude 121\u00b047.27\u2032E, 1783 m water depth) closely tracks changes in intermediate water ventilation and paleoproductivity over the last 460 kyr within one of the main outflow passages of the Indonesian Throughflow. Spectral analysis of five different flux-based productivity proxies indicates spectral power concentrated in the 100 kyr (glacial-interglacial) and the 23 kyr and 19 kyr (precessional) periods. Paleoproductivity maxima lead ice volume (benthic \u03b418O) maxima by 20\u00b0 to 40\u00b0 (\u223c1300 to 2600 years) at the precession band. The spectral differences in tropical paleoproductivity records from the Pacific and Indian oceans suggest that local processes (wind and circulation patterns driven by insolation) are dominant in driving productivity rather than large-scale tropical features. In the Timor Sea, productivity fluctuations over the last 460 kyr were strongly influenced by monsoonal wind patterns offshore NW Australia (23 and 19 kyr) and were also modulated by sea level\u2013related variations in the intensity of the Indonesian Throughflow (100 kyr).", "keyphrases": ["timor sea", "indian ocean", "insolation", "monsoonal wind pattern"]}
{"id": "10.1002/ar.20578", "title": "Linear and Geometric Morphometric Analysis of Long Bone Scaling Patterns in Jurassic Neosauropod Dinosaurs: Their Functional and Paleobiological Implications", "abstract": "Neosauropod dinosaurs were gigantic, herbivorous dinosaurs. Given that the limb skeleton is essentially a plastic, mobile framework that supports and moves the body, analysis of long bone scaling can reveal limb adaptations that supported neosauropod gigantism. Previously, analyses of linear dimensions have revealed a relatively isometric scaling pattern for the humerus and femur of neosauropods. Here, a combined scaling analysis of humerus and femur linear dimensions, cortical area, and shape across six neosauropod taxa is used to test the hypothesis that neosauropod long bones scaled isometrically and to investigate the paleobiological implications of these trends. A combination of linear regression and geometric morphometrics analyses of neosauropod humeri and femora were performed using traditional and thin\u2010plate splines approaches. The neosauropod sample was very homogeneous, and linear analyses revealed that nearly all humerus and femur dimensions, including cortical area, scale with isometry against maximum length. Thin\u2010plate splines analyses showed that little to no significant shape change occurs with increasing length or cortical area for the humerus or femur. Even with the exclusion of the long\u2010limbed Brachiosaurus, the overall trends were consistently isometric. These results suggest that the mechanical advantage of limb\u2010moving muscles and the relative range of limb movement decreased with increasing size. The isometric signal for neosauropod long bone dimensions and shape suggests these dinosaurs may have reached the upper limit of vertebrate long bone mechanics. Perhaps, like stilt\u2010walkers, the absolutely long limbs of the largest neosauropods allowed for efficient locomotion at gigantic size with few ontogenetic changes. Anat Rec, 290:1089\u20131111, 2007. \u00a9 2007 Wiley\u2010Liss, Inc.", "keyphrases": ["geometric morphometric analysis", "long bone", "dimension"]}
{"id": "10.1126/science.aav1446", "title": "The eruptive tempo of Deccan volcanism in relation to the Cretaceous-Paleogene boundary", "abstract": "Two timelines for extinction The Cretaceous-Paleogene extinction that wiped out the nonavian dinosaurs 66 million years ago was correlated with two extreme events: The Chicxulub impact occurred at roughly the same time that massive amounts of lava were erupting from the Deccan Traps (see the Perspective by Burgess). Sprain et al. used argon-argon dating of the volcanic ash from the Deccan Traps to argue that a steady eruption of the flood basalts mostly occurred after the Chicxulub impact. Schoene et al. used uranium-lead dating of zircons from ash beds and concluded that four large magmatic pulses occurred during the flood basalt eruption, the first of which preceded the Chicxulub impact. Whatever the correct ordering of events, better constraints on the timing and rates of the eruption will help elucidate how volcanic gas influenced climate. Science, this issue p. 866, p. 862; see also p. 815 The large impact associated with the demise of nonavian dinosaurs may have preceded the eruption of vast amounts of magma. Late Cretaceous records of environmental change suggest that Deccan Traps (DT) volcanism contributed to the Cretaceous-Paleogene boundary (KPB) ecosystem crisis. However, testing this hypothesis requires identification of the KPB in the DT. We constrain the location of the KPB with high-precision argon-40/argon-39 data to be coincident with changes in the magmatic plumbing system. We also found that the DT did not erupt in three discrete large pulses and that >90% of DT volume erupted in <1 million years, with ~75% emplaced post-KPB. Late Cretaceous records of climate change coincide temporally with the eruption of the smallest DT phases, suggesting that either the release of climate-modifying gases is not directly related to eruptive volume or DT volcanism was not the source of Late Cretaceous climate change.", "keyphrases": ["eruption", "volcanism", "cretaceous-paleogene boundary"]}
{"id": "paleo.006998", "title": "Magnification and resolution in dental microwear analysis using light microscopy", "abstract": "One potentially problematic aspect of dental microwear analysis is sensitivity to the resolution (fineness of detail) at which dental wear surfaces are viewed. Magnification is one of many variables that determine resolution. Microwear studies based on light microscopy generally report magnifications ranging from 30X-100X, although ambiguities in reported methods prohibit duplication of the resolutions of many studies. Moreover, magnification settings have been arbitrary and, thus far, the biasing effects of different resolutions have not been tested. We tested sensitivity of dental microwear analysis to resolution by manipulating pixel density and magnification in photomicrographs taken under a light microscope using the molars of a browser (moose), grazer (zebra), and frugivore/hard object feeder (peccary). Resolution affected the number of observable microwear features and distorted the proportional frequencies of large and small features. Nonetheless, two observers independently found similar differences between the species throughout a range of resolutions. At no resolution did observers recover statistically undifferentiated data, although interobserver correlation was best when resolution was decreased to 20-40% of the initial resolution. Observer correlation for microwear features with a maximal dimension >20 \u03bcm was substantially better than for smaller features. We conclude that (1) dimensionless aspects of microwear data (e.g., proportional numbers of scratches between species) are more robust to resolution than raw frequency data, (2) higher resolution does not produce higher quality data, and (3) the optimal resolution may be dependent upon the size of the microwear features. Further testing of the interaction of resolution, microwear feature size, and the observer will increase repeatability of results and lead to more robust paleodietary interpretations.", "keyphrases": ["resolution", "dental microwear analysis", "light microscopy", "scratch"]}
{"id": "paleo.008307", "title": "Gavialis from the Pleistocene of Thailand and Its Relevance for Drainage Connections from India to Java", "abstract": "Background The genus Gavialis comprises a single living but endangered species, G. gangeticus, as well as fossil species recorded in the Miocene to Pleistocene deposits of the Indian subcontinent. The genus is also represented in the Pleistocene deposits of Java by the species G. bengawanicus, which was recently recognized to be valid. Surprisingly, no detailed report of the genus exists between these two provinces and the recent evolutionary history of Gavialis is not understood. Methodology/Principal Findings We report new material consisting of skull and mandibular remains of Gavialis from the Early Pleistocene of Khok Sung, Nakhon Ratchasima Province, northeastern Thailand. The Gavialis material described herein is attributed to Gavialis cf. bengawanicus and sheds new light on the occurrence of the genus in mainland SE Asia. Conclusions/Significance Comparison of this new material with other species referred to the genus Gavialis led us to preliminary restrict the content of the genus to three species, namely G. gangeticus Gmelin, G. bengawanicus Dubois and G. lewisi Lull. The occurrence of G. cf. bengawanicus in Thailand allows us to propose a scenario for the dispersal of Gavialis from Indo-Pakistan to Indonesia, thus bridging a geographical gap between these two provinces. Dispersal by sea appears a less likely possibility than dispersal through fluvial drainages.", "keyphrases": ["pleistocene", "java", "gavialis"]}
{"id": "paleo.001915", "title": "Cladistic analysis of Caseidae (Caseasauria, Synapsida): using the gap\u2010weighting method to include taxa based on incomplete specimens", "abstract": "Occupying the role of primary consumer and having an early\u2013middle Permian age range, caseids (Caseasauria, Synapsida) are fundamental to the interpretation of the early history of terrestrial vertebrate ecosystems. Despite this importance, no comprehensive, species\u2010level phylogenetic study of Caseidae has yet been performed. Herein, we present a phylogenetic analysis of the group, using gap weighting to include poorly known taxa. Besides the description and comments on the resultant topologies, some more general issues concerning cladistic methodologies are briefly addressed. This study highlights the importance of a total\u2010evidence approach, including as many within\u2010group taxa and characters as possible. Continuously varying characters, in the form of indices derived from measurement of individual skeletal elements, proved to be highly important, adding significantly to the resolution of, and support for, recovered trees. The utility of the postcranial skeleton in understanding relationships among basal synapsids is highlighted.", "keyphrases": ["caseidae", "caseasauria", "synapsida"]}
{"id": "10.1098/rspb.2003.2521", "title": "Exhaustive sample set among Viverridae reveals the sister-group of felids: the linsangs as a case of extreme morphological convergence within Feliformia", "abstract": "Although molecular studies have helped to clarify the phylogeny of the problematic family Viverridae, a recent phylogenetic investigation based on cytochrome b (cyt b) has excluded the Asiatic linsangs (genus Prionodon) from the family. To assess the phylogenetic position of the Asiatic linsangs within the Feliformia, we analysed an exhaustive taxonomic sample set with cyt b and newly produced transthyretin intron I sequences (TR\u2013I\u2013I). TR\u2013I\u2013I alone and cyt b+TR\u2013I\u2013I combined (maximum\u2013likelihood analysis) highly support the position of Asiatic linsangs as sister\u2013group of the Felidae. The estimation of minimum divergence dates from molecular data suggests a splitting event ca. 33.3 million years (Myr) ago, which lends support to historical assertions that the Asiatic linsangs are \u2018living fossils\u2019 that share a plesiomorphic morphotype with the Oligocene feliform Paleoprionodon. The African linsang is estimated to appear more than 20 Myr later and represents the sister\u2013group of the genus Genetta. Our phylogenetic results illustrate numerous morphological convergences of \u2018diagnostic\u2019 characters among Feliformia that might be problematic for the identification of fossil taxa. The morphotype reappearance from the Asiatic to the African linsangs suggests that the genome of the Feliformia conserved its potential ability of expression for a peculiar adaptive phenotype throughout evolution, in this case arboreality and hypercarnivory in tropical forest.", "keyphrases": ["viverridae", "morphological convergence", "feliformia", "molecular data"]}
{"id": "10.1144/jm.2.1.111", "title": "Observations on surface ornamentation in fossil Ostracoda", "abstract": "It has recently been demonstrated (Okada, 1982) that some reticulate Ostracoda develop ornamentation by a process which reflects the arrangement of underlying epidermal cells. Pitting and secondary reticulation are also characteristic of many such forms, either during ontogeny or phylogeny, and as these features are of lesser dimensions than epidermal cells, a process at variance with that described by Okada must be responsible for their production. Outlined below is evidence from fossil Ostracoda supporting the hypothesis that actual valve resorption may occur during ontogeny to produce these second order features.", "keyphrases": ["ornamentation", "fossil ostracoda", "ostracod carapace"]}
{"id": "paleo.007935", "title": "More than 100 years of a mistake: on the anatomy of the atlas of the enigmatic Macrauchenia patachonica", "abstract": "Ever since the discovery of the first remains of Macrauchenia patachonica by Charles Darwin in 1834, this taxon has puzzled researchers with its peculiar anatomy. Being the best-known member of the family Macraucheniidae and with fossil records in extensive areas of South America between the Middle to Late Pleistocene/earliest Holocene, M. patachonica has been extensively studied over decades, and recently even included in molecular studies. However, there are some elements of its skeleton that have been inadvertently unstudied. One of these elements is the atlas of M. patachonica that due to a misidentification made 159 years ago by the prominent zoologist Hermann Burmeister, was not examined or illustrated by later researchers even with access to excellent specimens. Here, we describe and illustrate the atlas of M. patachonica for the first time, correcting Burmeister's mistake. Overall, the anatomy of the atlas of M. patachonica is consistent with the anatomy of older macraucheniids. The atlas described by Burmeister as being M. patachonica probably corresponds to that of a bovid. It is noteworthy that most mounted skeletons of M. patachonica present today in museum exhibitions, display a correct atlas derived from a more complete specimen discovered ca. 1904 by the prominent palaeontologist Santiago Roth.", "keyphrases": ["mistake", "anatomy", "macrauchenia patachonica", "pleistocene"]}
{"id": "10.1111/j.1466-8238.2010.00643.x", "title": "Mammal community structure correlates with arboreal heterogeneity in faunally and geographically diverse habitats: implications for community convergence", "abstract": "Aim\u2002 To quantify how mammal community structure relates to heterogeneity of vegetation for palaeoecological reconstructions, and to test whether historical or environmental factors are more important in structuring communities. \n \n \n \nLocation\u2002 Sixty-three natural protected areas in Asia, Africa and South and Central America. \n \n \n \nMethods\u2002 We defined faunal communities by allocating species to ecological guilds and calculating proportional representation within each guild. Vegetation heterogeneity for each natural protected area was calculated from satellite images. The relationship between these ecospaces was calculated using canonical correlations analysis, redundancy analysis and principal components analysis. We expected that large, herbivorous mammals would be most strongly correlated with open areas. Convergence was tested by independently eliminating the effects of geography and vegetation heterogeneity on the structure of the mammal communities. We expected that vegetation would more strongly structure communities than geographical position. \n \n \n \nResults\u2002 We show that the guild structure of communities across habitats is significantly correlated with vegetation heterogeneity. The highest correlation was between small, scansorial-arboreal secondary consumers and heavy tree cover. The first convergence analysis shows American communities distinguished from Asian and African communities; these latter communities show a remarkable convergence in structure. Historical factors only affected the continent whose mammals had experienced a long period of isolation. The second convergence analysis shows that almost all biomes have the same or very similar community structure regardless of continent. \n \n \n \nMain conclusions\u2002 Communities from the same environments in different continents showed remarkable convergence. Communities from the same continents only converged when those continents shared a recent geological and biological history. These results suggest that historical and environmental factors are operating over different timescales. This study confirms that environmental reconstructions made on the basis of whole communities will accurately reflect the environment that the community lived in. However, reconstructions made for fossil sites in deep time need to take historical factors into consideration. Small, arboreal and scansorial secondary consumers show the strongest correlation with vegetation, correlating with continuous tree canopy cover. This relationship allows simple reconstructions of the amount of tree cover occurring in a landscape from the proportion of species from the community falling in this ecological guild.", "keyphrases": ["heterogeneity", "palaeoecological reconstruction", "mammal community structure"]}
{"id": "10.1111/evo.14219", "title": "Exploring adaptive landscapes across deep time: A case study using echinoid body size", "abstract": "Adaptive landscapes are a common way of conceptualizing the phenotypic evolution of lineages across deep time. Although multiple approaches exist to implement this concept into operational models of trait evolution, inferring adaptive landscapes from comparative datasets remains challenging. Here, I explore the macroevolutionary dynamics of echinoid body size using data from over 5000 specimens and a phylogenetic framework incorporating a dense fossil sampling and spanning approximately 270 million years. Furthermore, I implement a novel approach of exploring alternative parameterizations of adaptive landscapes that succeeds in finding simpler, yet better\u2010fitting models. Echinoid body size has been constrained to evolve within a single adaptive optimum for much of the clade's history. However, most of the morphological disparity of echinoids was generated by multiple regime shifts that drove the repeated evolution of miniaturized and gigantic forms. Events of body size innovation occurred predominantly in the Late Cretaceous and were followed by a drastic slowdown following the Cretaceous\u2010Paleogene mass extinction. The discovery of these patterns is contingent upon directly sampling fossil taxa. The macroevolution of echinoid body size is therefore characterized by a late increase in disparity (likely linked to an expansion of ecospace), generated by active processes driving lineages toward extreme morphologies.", "keyphrases": ["adaptive landscape", "deep time", "echinoid body size", "macroevolutionary dynamic"]}
{"id": "10.1126/science.1194585", "title": "Amazonia Through Time: Andean Uplift, Climate Change, Landscape Evolution, and Biodiversity", "abstract": "The Making of Amazonian Diversity The biodiversity of the Amazon Basin is legendary, but the processes by which it has been generated have been debated. In the late 20th century the prevalent view was that the engine of diversity was repeated contraction and expansion of forest refugia during the past 3 million years or so. Hoorn et al. (p. 927) analyze findings from a diverse range of disciplines, including molecular phylogeny, ecology, sedimentology, structural geology, and palaeontology, to offer an overview of the entire history of this region during the Cenozoic era (66 million years ago). The uplift of the Andes was a pivotal event in the evolution of Amazonian landscapes because it continually altered river drainage patterns, which in turn put a variety of pressures on organisms to adapt to changing conditions in a multiplicity of ways. Hence, the diversity of the modern biota of the Amazon has more ancient origins than previously thought. The Amazonian rainforest is arguably the most species-rich terrestrial ecosystem in the world, yet the timing of the origin and evolutionary causes of this diversity are a matter of debate. We review the geologic and phylogenetic evidence from Amazonia and compare it with uplift records from the Andes. This uplift and its effect on regional climate fundamentally changed the Amazonian landscape by reconfiguring drainage patterns and creating a vast influx of sediments into the basin. On this \u201cAndean\u201d substrate, a region-wide edaphic mosaic developed that became extremely rich in species, particularly in Western Amazonia. We show that Andean uplift was crucial for the evolution of Amazonian landscapes and ecosystems, and that current biodiversity patterns are rooted deep in the pre-Quaternary.", "keyphrases": ["andean uplift", "biodiversity", "amazonia", "gondwanan landmass", "marine transgression"]}
{"id": "10.1002/jqs.659", "title": "Dinoflagellate cyst assemblages as tracers of sea\u2010surface conditions in the northern North Atlantic, Arctic and sub\u2010Arctic seas: the new \u2018n = 677\u2019 data base and its application for quantitative palaeoceanographic reconstruction", "abstract": "The distribution of dinoflagellate cyst (dinocyst) assemblages in surface sediment samples from 677 sites of the northern North Atlantic, Arctic and sub\u2010Arctic seas is discussed with emphasis on the relationships with sea\u2010surface parameters, including sea\u2010ice cover, salinity and temperature of the coldest and warmest months. Difficulties in developing a circum\u2010Arctic data base include the morphological variation within taxa (e.g. Operculodinium centrocarpum, Islandinium? cezare and Polykrikos sp.), which probably relate to phenotypic adaptations to cold and/or low salinity environments. Sparse hydrographical data, together with large interannual variations of temperature and salinity in surface waters of Arctic seas constitute additional limitations. Nevertheless, the use of the best\u2010analogue technique with this new dinocyst data base including 677 samples permits quantitative reconstruction of sea\u2010surface conditions at the scale of the northern North Atlantic and the Arctic domain. The error of prediction calculated from modern assemblages is \u00b11.3 \u00b0C and \u00b11.8 \u00b0C for the temperature of February and August, respectively, \u00b11.8 for the salinity, and \u00b11.5 months yr\u22121 for the sea\u2010ice cover. Application to late Quaternary sequences from the western and eastern subpolar North Atlantic (Labrador Sea and Barents Sea) provide reconstructions compatible with those obtained using the previous dinocyst data base (n = 371), which mainly included modern data from the northern North Atlantic. Copyright \u00a9 2001 John Wiley & Sons, Ltd.", "keyphrases": ["cyst", "northern north atlantic", "sub\u2010arctic sea"]}
{"id": "paleo.004546", "title": "New carnivoraforms (Mammalia) from the middle Eocene of California, USA, and comments on the taxonomic status of 'Miacis' gracilis", "abstract": "The middle Eocene constitutes an important period for understanding the early evolution of carnivoraforms and the origin of crown-group carnivorans. Here I describe two new genera of carnivoraforms from the Uintan North American Land Mammal Age of southern California, and report hitherto-undescribed specimens of Procynodictis progressus, 'Miacis' gracilis, 'Miacis' hookwayi, and two undeterminate taxa to bridge some of the gaps in taxonomic knowledge. Specifically, the fossil materials described here support the placement of P. vulpiceps and P. progressus in the same genus but suggest their distinct identities at the species level. Similarly, 'M.' gracilis, which has been synonymized with P. vulpiceps by some authors, is considered a separate species from both P. vulpiceps and P. progressus. A minimum of 11 carnivoraform taxa are recognized in the middle Eocene of southern California, including nine from the late Uintan to the earliest Duchesnean (ca. 43-41 Ma ago). Of the latter, at least six taxa are apparently endemic to this region, thus conforming to the high provinciality of North American mammalian faunas during this time. In addition to the carnivoraforms, four taxa of creodonts and a mesonychid are known. The notably high taxonomic richness of middle-Eocene mammalian carnivores in southern California is associated with high diversity of non-carnivorous mammals known from there; this pattern agrees with the correlation between mammalian predator and prey diversity that has previously been observed at various spatiotemporal scales. The stratigraphic distributions of the late-Uintan taxa reported here are consistent with the recently revised ages of vertebrate assemblages from the Sespe Formation of Ventura County, California, in the parsimonious sense.", "keyphrases": ["carnivoraform", "middle eocene", "gracilis"]}
{"id": "paleo.005969", "title": "The evolutionary convergence of mid-Mesozoic lacewings and Cenozoic butterflies", "abstract": "Mid-Mesozoic kalligrammatid lacewings (Neuroptera) entered the fossil record 165 million years ago (Ma) and disappeared 45 Ma later. Extant papilionoid butterflies (Lepidoptera) probably originated 80\u201370 Ma, long after kalligrammatids became extinct. Although poor preservation of kalligrammatid fossils previously prevented their detailed morphological and ecological characterization, we examine new, well-preserved, kalligrammatid fossils from Middle Jurassic and Early Cretaceous sites in northeastern China to unravel a surprising array of similar morphological and ecological features in these two, unrelated clades. We used polarized light and epifluorescence photography, SEM imaging, energy dispersive spectrometry and time-of-flight secondary ion mass spectrometry to examine kalligrammatid fossils and their environment. We mapped the evolution of specific traits onto a kalligrammatid phylogeny and discovered that these extinct lacewings convergently evolved wing eyespots that possibly contained melanin, and wing scales, elongate tubular proboscides, similar feeding styles, and seed\u2013plant associations, similar to butterflies. Long-proboscid kalligrammatid lacewings lived in ecosystems with gymnosperm\u2013insect relationships and likely accessed bennettitalean pollination drops and pollen. This system later was replaced by mid-Cretaceous angiosperms and their insect pollinators.", "keyphrases": ["lacewing", "butterfly", "kalligrammatid lacewing", "northeastern china"]}
{"id": "10.1080/02724634.2011.550366", "title": "New Saber-Toothed Cat Records (Felidae: Machairodontinae) for the Pleistocene of Venezuela, and the Great American Biotic Interchange", "abstract": "ABSTRACT \n The Machairodontinae fossil record in South America is not very diverse. Until now, only the genus Smilodon (Smilodontini) has been reported, with likely a single species, S. populator. A second taxon of Machairodontinae was referred to Homotheriini and to the genus Xenosmilus, but the age to which it was assigned, early to middle Pleistocene, is uncertain, because it was recovered out of stratigraphic context. At present, the Venezuelan saber-toothed cat record is limited to the late Pleistocene, and consists of fossils found in Mene de Inciarte (state of Zulia), and from Zumbador cave deposit in the state of Falc\u00f3n. Here we report a new species of Machairodontinae Homotherium venezuelensis, nov. sp., as well as the first record of Smilodon gracilis in South America. Both were found in El Breal de Orocual, a tar seep in the state of Monagas, northeastern Venezuela. The age of the deposit has been interpreted as early to middle Pleistocene by thermoluminescence dating. We have been able to identify 30 vertebrate taxa, suggesting a paleoenvironment similar to the Venezuelan llanos today: an extensive savanna with rivers and patches of gallery forest. The saber-toothed cats described here demonstrate that the biogeography of Neotropical felids is more complex than previously thought, and allow us to identify new invasions and delimit the times during which they occurred. The fossils from Orocual represent the first record of Homotherium for South America, indicating that scimitar-toothed cats invaded this continent as early as the early\u2014middle Pleistocene.", "keyphrases": ["machairodontinae", "pleistocene", "venezuela"]}
{"id": "paleo.011898", "title": "A Historical Overview of the Classification, Evolution, and Dispersion of Leishmania Parasites and Sandflies", "abstract": "Background The aim of this study is to describe the major evolutionary historical events among Leishmania, sandflies, and the associated animal reservoirs in detail, in accordance with the geographical evolution of the Earth, which has not been previously discussed on a large scale. Methodology and Principal Findings Leishmania and sandfly classification has always been a controversial matter, and the increasing number of species currently described further complicates this issue. Despite several hypotheses on the origin, evolution, and distribution of Leishmania and sandflies in the Old and New World, no consistent agreement exists regarding dissemination of the actors that play roles in leishmaniasis. For this purpose, we present here three centuries of research on sandflies and Leishmania descriptions, as well as a complete description of Leishmania and sandfly fossils and the emergence date of each Leishmania and sandfly group during different geographical periods, from 550 million years ago until now. We discuss critically the different approaches that were used for Leishmana and sandfly classification and their synonymies, proposing an updated classification for each species of Leishmania and sandfly. We update information on the current distribution and dispersion of different species of Leishmania (53), sandflies (more than 800 at genus or subgenus level), and animal reservoirs in each of the following geographical ecozones: Palearctic, Nearctic, Neotropic, Afrotropical, Oriental, Malagasy, and Australian. We propose an updated list of the potential and proven sandfly vectors for each Leishmania species in the Old and New World. Finally, we address a classical question about digenetic Leishmania evolution: which was the first host, a vertebrate or an invertebrate? Conclusions and Significance We propose an updated view of events that have played important roles in the geographical dispersion of sandflies, in relation to both the Leishmania species they transmit and the animal reservoirs of the parasites.", "keyphrases": ["classification", "dispersion", "sandfly", "leishmaniasis", "trypanosomatidae"]}
{"id": "10.1073/pnas.1006460107", "title": "Ancient pinnate leaf mimesis among lacewings", "abstract": "Insects have evolved diverse methods of predator avoidance, many of which implicate complex adaptations of their wings (e.g., Phylliidae, Nymphalidae, Notodontidae). Among these, angiosperm leaf mimicry is one of the most dramatic, although the historical origins of such modifications are unclear owing to a dearth of paleontological records. Here, we report evidence of pinnate leaf mimesis in two lacewings (Neuroptera): Bellinympha filicifolia Y. Wang, Ren, Liu & Engel gen. et sp. nov. and Bellinympha dancei Y. Wang, Ren, Shih & Engel, sp. nov., from the Middle Jurassic, representing a 165-million-year-old specialization between insects and contemporaneous gymnosperms of the Cycadales or Bennettitales. Furthermore, such lacewings demonstrate a preangiosperm origin for leaf mimesis, revealing a lost evolutionary scenario of interactions between insects and gymnosperms. The current fossil record suggests that this enigmatic lineage became extinct during the Early Cretaceous, apparently closely correlated with the decline of Cycadales and Bennettitales at that time, and perhaps owing to the changing floral environment resulted from the rise of flowering plants.", "keyphrases": ["pinnate leaf mimesis", "lacewing", "wing"]}
{"id": "paleo.002535", "title": "A method for improved identification of postcrania from mammalian fossil assemblages: multivariate discriminant function analysis of camelid astragali", "abstract": "Character-rich craniodental specimens are often the best material for identifying mammalian fossils to the genus or species level, but what can be done with the many assemblages that consist primarily of dissociated postcrania? In localities lacking typically diagnostic remains, accurate identification of postcranial material can improve measures of mammalian diversity for wider-scale studies. Astragali, in particular, are often well-preserved and have been shown to have diagnostic utility in artiodactyls. The Thousand Creek fauna of Nevada (~8 Ma) represents one such assemblage rich in postcranial material but with unknown diversity of many taxa, including camelids. We use discriminant function analysis (DFA) of eight linear measurements on the astragali of contemporaneous camelids with known taxonomic affinity to produce a training set that can then be used to assign taxa to the Thousand Creek camelid material. The discriminant function identifies, at minimum, four classes of camels: \"Hemiauchenia\", Alforjas, Procamelus, and ?Megatylopus. Adding more specimens to the training set may improve certainty and accuracy for future work, including identification of camelids in other faunas of similar age. For best statistical practice and ease of future use, we recommend using DFA rather than qualitative analyses of biplots to separate and diagnose taxa.", "keyphrases": ["postcrania", "discriminant function analysis", "astragali"]}
{"id": "paleo.000245", "title": "GLIRIDAE (RODENTIA, MAMMALIA) FROM THE LATE MIOCENE FISSURE FILLING BIANCONE 1 (GARGANO, PROVINCE OF FOGGIA, ITALY)", "abstract": "Two new species of the endemic genus Stertomys (Mammalia, Rodentia, Gliridae) are described from the Late Miocene fissure filling Biancone 1 on the palaeoisland Gargano (Province of Foggia, Italy): S. daamsi and S. daunius. A third new species, Dryomys apulus, presents no endemic features at the generic level and is assigned to the extant genus Dryomys. The new taxa suggest that faunal immigration to Gargano occurred in one event, and that the Biancone deposit is, at most, Late Miocene in age. Additionally, an analysis of all fossil Myomiminae argues that Stertomys belongs to that subfamily, and that it may be derived from Myomimus dehmi or Miodyromys aegercii.", "keyphrases": ["rodentia", "mammalia", "late miocene fissure"]}
{"id": "10.1017/S0016774600001578", "title": "Loess in the Vojvodina region (Northern Serbia): an essential link between European and Asian Pleistocene environments", "abstract": "Abstract Loess deposits in the Vojvodina region, northern Serbia, are among the oldest and most complete loess-paleosol sequences in Europe to date. These thick sequences contain a detailed paleoclimatic record from the late Early Pleistocene. Based on the correlation of detailed magnetic susceptibility (MS) records from Vojvodina with the Chinese loess record and deep-sea isotope stratigraphy we here reconfirm and expand on a stratigraphic model of the Vojvodinian loess-paleosol chronostratigraphic sequence following the Chinese loess stratigraphic system. Variations in MS, dust accumulation rates, and the intensity of pedogenesis demonstrate evidence for a Middle Pleistocene climatic and environmental transition. The onset of loess deposition in Vojvodina also indicates a direct link between dust generation in Europe and that in the interior of Eurasia since the Early Pleistocene. The youngest part of the Early Pleistocene and oldest part of the Middle Pleistocene is characterised by relatively uniform dust accumulation and soil formation rates as well as relatively high magnetic susceptibility values. In contrast, the last five interglacial-glacial cycles are characterised by sharp environmental differences between high dust accumulation rates during the glacials and low rates observed during soil development. The data presented in this study demonstrate the great potential of Vovjodina's loess archives for accurate reconstruction of continental Eurasian Pleistocene climatic and environmental evolution.", "keyphrases": ["vojvodina region", "northern serbia", "loess"]}
{"id": "paleo.001769", "title": "Statoliths from the Jurassic succession of south-west England, United Kingdom", "abstract": "The occurrence of statoliths within the Jurassic succession of south-west England and other parts of Europe is reviewed. Five 'morphospecies' have been identified, ranging in age from Hettangian to Kimmeridgian. With so little published information on statoliths, the presently known geological record is incomplete, although new occurrences are continually being discovered. The occurrence of statoliths, in the absence of soft-bodied fossils, may ultimately provide a more complete indication of the distribution of the soft-bodied host animals. At the present time, however, only one of the statolith 'morphospecies' can be, tentatively, linked to a known species of teuthid.", "keyphrases": ["jurassic succession", "south-west england", "statolith"]}
{"id": "paleo.004240", "title": "Triassic coleoid beaks and other structures \nfrom the Calcareous Alps revisited", "abstract": "A. 2022. Triassic coleoid beaks and other structures from the Calcareous Alps. Acta Palaeontologica Polonica 67 (X): xxx\u2013xxx. We performed comprehensive study of seven Carnian, Late Triassic specimens of a coleoid cephalopod Phragmoteuthis bisinuata , on which Suess based his hypothesis on \u201cbeaks of P. bisinuata \u201d. Using SEM/EDS, we found that \u201cbeaks of P. bisinuata \u201d consist of a micro-granular carbonized matrix containing ~4\u201330 \u03bcm diameter and ~50\u2013200 \u03bcm visible length, dense calcified bone-like micro-structures. This strongly suggests that these objects are vertebrate bone-inducing cartilages in which the matrix was post-mortem reworked by carbon-accumulating bacteria and substituted by nano-particles of carbon accumulated in micro-granules. Hence, the presumed \u201cbeaks of P. bisinuata \u201d are cartilaginous remains of a prey, presum-ably juvenile fish. This data dismissed the entire hypothesis of Seuss. A small spatula-shape plate with a rachis-like process in an association with 10 or so imprints around (arm crown), found in front of a proostracum of P. bisinuata evidences an unknown Late Triassic juvenile teuthid which possessed a gladius resembling that of the early Permian Glochinomorpha stifeli. It inhabited the open sea area of the northwestern Tethys Ocean, and was, along with juvenile fishes, in the diet of P. bisinuata . The first identified Anisian (Middle Triassic) coleoid beak is represented by an isolated specimen from the Gardena Valley, NE Italy. It has a typical composition and morphology of coleoid upper beak: chitinous, wide-oval lateral walls, short wings, and pointed hook-like rostrum. This suggests similar upper beak structure in the Carnian P. bisinuata in which the lower beaks were apparently similar to that of the co-occurring Lunzoteuthis schindelbergensis and had a widely open outer lamella with posteriorly elongated paired wings joined into a pointed rostrum in the anterior portion.", "keyphrases": ["calcareous alps", "proostracum", "triassic coleoid beak"]}
{"id": "10.3389/feart.2023.1160285", "title": "The significance of Anomalocaris and other Radiodonta for understanding paleoecology and evolution during the Cambrian explosion", "abstract": "One of the most widespread and diverse animal groups of the Cambrian Explosion is a clade of stem lineage arthropods known as Radiodonta, which lived exclusively in the early Paleozoic. First reported in 1892 with Anomalocaris canadensis, radiodonts are now one of the best known early animal groups with excellent representation in the fossil record, and are ubiquitous components of Konservat-Lagerst\u00e4tten from the Cambrian and the Early Ordovician. These large swimmers were characterised by a segmented body bearing laterally-oriented flaps, and a head with a distinct radial oral cone, a pair of large frontal appendages adapted for different feeding modes, compound eyes on stalks, and prominent head carapaces. Radiodonts inform on the paleoecology of early animal communities and the steps involved in euarthropod evolution. Four families within Radiodonta have been established. The raptorial predator families Anomalocarididae and Amplectobeluidae were dominant early in the evolutionary history of Radiodonta, but were later overtaken by the mega-diverse and widespread Hurdiidae, which has a more generalised sediment-sifting predatory mode. Suspension feeding, notably in the families Tamisiocarididae and Hurdiidae, also evolved at least twice in the history of the clade. The well-preserved anatomical features of the radiodont body and head have also provided insights into the evolution of characteristic features of Euarthropoda, such as the biramous limbs, compound eyes, and organisation of the head. With 37 species recovered from all major paleocontinents of the Cambrian and Early Ordovician, Radiodonta provides a unique opportunity for revealing evolutionary patterns during the Cambrian Explosion.", "keyphrases": ["radiodonta", "paleoecology", "cambrian explosion", "oral cone"]}
{"id": "10.1017/S0094837300016328", "title": "Is predation intensity reduced with increasing depth? Evidence from the west Atlantic stalked crinoid Endoxocrinus parrae (Gervais) and implications for the Mesozoic marine revolution", "abstract": "The number of regenerated arms was counted on specimens of two distinct phenotypes of the stalked crinoid Endoxocrinus parrae (Gervais) from a wide bathymetric range in the Caribbean (178-723 m). In one phenotype, the sample was divided into two groups, one from shallower (< 500 m) depths, the other from deeper (\u2265 500 m); in the other phenotype the group divided at 550 m. In both phenotypes, the frequency of regenerated arms is significantly higher in specimens from shallower water than in those from deeper water. If the regenerated arms in Endoxocrinus parrae were the result of sublethal predation, as previously suggested, then predation intensity is higher in shallow water than deep water. These results are consistent with the idea of the late Mesozoic marine revolution\u2014that there has been stronger predation on various invertebrates in shallow-water environments since the late Mesozoic. The stalked crinoids may have been unable to cope with increased predation in shelf environments, and they migrated to offshore environments.", "keyphrases": ["predation intensity", "depth", "gervais"]}
{"id": "10.1017/jpa.2018.68", "title": "Tarimspira from the Cambrian (Series 2, Stage 4) of Laurentia (Greenland): extending the skeletal record of paraconodontid vertebrates", "abstract": "Abstract. Phosphatic sclerites of the problematic Tarimspira Yue and Gao, 1992 (Cambrian Series 2) recovered by weak acid maceration of limestones display a unique range of mainly strongly coiled morphologies. They were likely organized into multielement scleritomes, but the nature of these is poorly known; some sclerites may have had a grasping function. Tarimspira sclerites grew by basal accretion in an analogous fashion to younger paraconodonts (Cambrian Series 3\u20134) but lack a basal cavity. Based on proposed homologies, Tarimspira may provide an extension of the early vertebrate paraconodont\u2013euconodont clade back into the early Cambrian. Tarimspira is described for the first time from Laurentia (North Greenland), extending its known range from China and Siberia in Cambrian Series 2. In addition to the type species, Tarimspira plana Yue and Gao, 1992, the Greenland record of Tarimspira includes two morphotypes of a new species, Tarimspira artemi.", "keyphrases": ["paraconodont", "basal cavity", "tarimspira"]}
{"id": "10.4072/RBP.2018.3.04", "title": "The first record of Ascaridoidea eggs discovered in Crocodyliformes hosts from the Upper Cretaceous of Brazil", "abstract": "A paleoparasitological investigation was carried out on Crocodyliformes coprolites discovered in the Municipality of Santo Anastacio, in the southwestern region of the State of Sao Paulo. Individual samples were extracted from the surface and internal portion of each coprolite which revealed the presence of thick-shelled parasite eggs in three of them. The morphological characteristics of the specimens, i.e., rounded or oval shape, thick-shelled with mammillated surface, as well as their size, suggest that these eggs belong to the superfamily Ascaridoidea, which are gastrointestinal parasite nematodes of vertebrates, popularly known as \u201croundworms\u201d. This is the first record of Ascaridoidea eggs discovered in Crocodyliformes hosts from the Upper Cretaceous of Brazil.", "keyphrases": ["ascaridoidea egg", "crocodyliformes host", "parasite egg"]}
{"id": "10.3853/j.0067-1975.44.1992.38", "title": "The Sinolepidae, a family of antiarchs (placoderm fishes) from the Devonian of South China and eastern Australia", "abstract": "Two new antiarchs are described, from the Late Devonian Hunter Siltstone near Grenfell in south-eastern Australia (Grenfellaspis branagani n.gen., n.sp.), and from the Early Middle Devonian Dayaoshan Group in Guangxi, south-eastern China (Dayaoshania youngi n.gen., n.sp.). New material is described of Xichonolepis qujingensis P'an & Wang, 1978 from the Middle Devonian of Yunnan, and new interpretations are presented for Sinolepis Liu & P'an, 1958 from the Late Devonian of Jiangsu. All four genera are placed in the family Sinolepidae Liu & P' an, of which the most obvious defining character is the much reduced ventral laminae of the anterior and posterior ventrolateral plates of the trunk armour, and the presumed absence of a median ventral plate. Emended diagnoses are presented for the family Sinolepidae and the genera Xichonolepis and Sinolepis. It is suggested that Grenfellaspis and Sinolepis are immediately related, and the biostratigraphic, biogeographic, and palaeogeographic implications of this relationship are discussed. The vertebrate fauna from the Hunter Siltstone is regarded as the youngest nonmarine vertebrate horizon known from the Devonian of south-eastern Australia. A close palaeogeographic connection between south-eastern Australia and South and North China is indicated for the latest Devonian and earliest Carboniferous (late Famennian-early Tournaisian), which contrasts with the distinctive Devonian vertebrate faunas from the two regions in earlier strata. Other Devonian fossil groups showing a similar biogeographic pattern are considered in the context of competing hypotheses concerning the palaeogeographic relationships of Gondwana and Asia during the Middle Palaeozoic. 319 320 Records of the Australian Museum (1992) Vo1.44 RITCHIE, A., S. WANG, G.C. YOUNG & G. ZHANG, 1992. The Sinolepidae, a family of antiarchs (placoderm fishes) from the Devonian of South China and eastern Australia. Records of the Australian Museum 44(3): 319-370.", "keyphrases": ["sinolepidae", "placoderm fish", "south china"]}
{"id": "paleo.008560", "title": "Callibrachion and Datheosaurus, Two Historical and Previously Mistaken Basal Caseasaurian Synapsids from Europe", "abstract": "This study represents a re-investigation of two historical fossil discoveries, Callibrachion gaudryi (Artinskian of France) and Datheosaurus macrourus (Gzhelian of Poland), that were originally classified as haptodontine-grade sphenacodontians and have been lately treated as nomina dubia. Both taxa are here identified as basal caseasaurs based on their overall proportions as well as dental and osteological characteristics that differentiate them from any other major synapsid subclade. As a result of poor preservation, no distinct autapomorphies can be recognized. However, our detailed investigations of the virtually complete skeletons in the light of recent progress in basal synapsid research allow a novel interpretation of their phylogenetic positions. Datheosaurus might represent an eothyridid or basal caseid. Callibrachion shares some similarities with the more derived North American genus Casea. These new observations on Datheosaurus and Callibrachion provide new insights into the early diversification of caseasaurs, reflecting an evolutionary stage that lacks spatulate teeth and broadened phalanges that are typical for other caseid species. Along with Eocasea, the former ghost lineage to the Late Pennsylvanian origin of Caseasauria is further closed. For the first time, the presence of basal caseasaurs in Europe is documented.", "keyphrases": ["datheosaurus", "europe", "haptodontine-grade sphenacodontian", "sphenacodontian", "basal caseasaur"]}
{"id": "10.1002/rcm.7445", "title": "Glutamine deamidation: an indicator of antiquity, or preservational quality?", "abstract": "RATIONALE\nMuch credence has been given in the paleoproteomic community to glutamine deamidation as a proxy for the age of proteins derived from fossil and subfossil material, and this modification has been invoked as a means for determining the endogeneity of molecules recovered from very old fossil specimens.\n\n\nMETHODS\nWe re-evaluated the relationship between glutamine deamidation and geologic time by examining previously published data from five recent mass spectrometry studies of archeaological fossils. Deamidation values recovered for fossils were graphed against their reported chronologic age using WebPlotDigitizer.\n\n\nRESULTS\nThe experimental data that has been produced from fossil material to date show that the extent of glutamine deamidation does not correspond to the absolute age of the specimens being examined, but rather show extreme variation between specimens of similar age and taxonomic affinity.\n\n\nCONCLUSIONS\nBecause deamidation rates and levels can be greatly affected by numerous chemical and environmental factors, we propose that glutamine deamidation is better suited as an indicator of preservational quality and/or environmental conditions than a mark of the endogeneity or authenticity of ancient proteins.", "keyphrases": ["indicator", "preservational quality", "protein", "glutamine deamidation"]}
{"id": "10.4072/rbp.2022.1.03", "title": "Phytosaurian Nomenclature: Parasuchia, Phytosauria or Belodontia?", "abstract": "The nomenclatural status of Phytosaurus J\u00e6ger is here analyzed in accordance with the International Code of Zoological Nomenclature. In the past, several authors have interpreted it as both a family-group and/or a genus-group name, but each of these approaches fails in several articles of the Code. Phytosaurus J\u00e6ger is here interpreted as originally established for a collective-group and cannot be used as a nominal genus in binomina, but takes precedence over any other younger homonym, and the first available one is Phytosaurus Wagler. Being an invalid junior homonym, the class-group name Phytosauria Baur and the family-group name Phytosauridae Lydekker, which are based on Phytosaurus Wagler, are ultimately rejected. Conversely, the class-group names Parasuchia Huxley and Belodontia Brauns, as well as the family-group name Belodontidae Cope, are older but have some taxonomic restrictions in relation to Belodon plieningeri Meyer. To avoid proposing new names for old ones, the solution to fix the higher-order nomenclature for phytosaurs is to designate a neotype for Belodon plieningeri Meyer. Keywords: Parasuchia, Phytosauria, Belodontia, Archosauriformes, Triassic, collective-group.", "keyphrases": ["nomenclature", "parasuchia", "phytosauria", "belodontia"]}
{"id": "paleo.011807", "title": "Osteichthyan-like cranial conditions in an Early Devonian stem gnathostome", "abstract": "The phylogeny of Silurian and Devonian (443-358 million years ago [Ma]) fishes remains the foremost problem in the study of the origin of modern gnathostomes (jawed vertebrates). A central question concerns the morphology of the last common ancestor of living jawed vertebrates, with competing hypotheses advancing either a chondrichthyan-1-3 or osteichthyan-like4,5 model. Here we present Janusiscus schultzei gen. et sp. nov., an Early Devonian (ca. 415 Ma) gnathostome from Siberia previously interpreted as a ray-finned fish6, which provides important new information about cranial anatomy near the last common ancestor of chondrichthyans and osteichthyans. The skull roof of Janusiscus resembles that of early osteichthyans, with large plates bearing vermiform ridges and partially enclosed sensory canals. High-resolution computed tomography reveals a braincase bearing characters typically associated with either chondrichthyans (large hypophyseal opening accommodating the internal carotid arteries) or osteichthyans (facial nerve exiting through jugular canal, endolymphatic ducts exiting posterior to the skull roof) and lacking a ventral cranial fissure, the presence of which is considered a derived feature of crown gnathostomes7,8. A conjunction of well-developed cranial processes in Janusiscus helps unify the comparative anatomy of early jawed vertebrate neurocrania, suggesting primary homologies in \u2018placoderms\u2019, osteichthyans and chondrichthyans. Phylogenetic analysis further supports the chondrichthyan affinities of \u2018acanthodians\u2019, and places Janusiscus and the enigmatic Ramirosuarezia9 in a polytomy with crown gnathostomes. The close correspondence between the skull roof of Janusiscus and that of osteichthyans strongly suggests an extensive dermal skeleton was present in the last common ancestor of jawed vertebrates4, but ambiguities arise from uncertainties in the anatomy of Ramirosuarezia. The unexpected contrast between endoskeletal structure in Janusiscus and its superficially osteichthyan-like dermal skeleton highlights the potential significance of other incompletely known Siluro-Devonian \u2018bony fishes\u2019 for reconstructing patterns of trait evolution near the origin of modern gnathostomes.\nGnathostomata (Gegenbaur 1878)\nJanusiscus schultzei\ngen. et sp. nov", "keyphrases": ["stem gnathostome", "jawed vertebrate", "chondrichthyan", "osteichthyan", "phylogenetic analysis"]}
{"id": "paleo.010321", "title": "Biomechanical insights into the dentition of megatooth sharks (Lamniformes: Otodontidae)", "abstract": "The evolution of gigantism in extinct otodontid sharks was paralleled by a series of drastic modifications in their dentition including widening of the crowns, loss of lateral cusplets, and acquisition of serrated cutting edges. These traits have generally been interpreted as key functional features that enabled the transition from piscivory to more energetic diets based on marine mammals, ultimately leading to the evolution of titanic body sizes in the most recent forms (including the emblematic Otodus megalodon). To investigate this hypothesis, we evaluate the biomechanics of the anterior, lateral, and posterior teeth of five otodontid species under different loading conditions by using two-dimensional finite element analysis. Stress distribution patterns are remarkably similar among all models under puncture and draw (i.e., when subjected to vertical and lateral forces, respectively). Contrary to expectation, higher average stress values are detected under both loading scenarios in more recent species. Altogether, this suggests little correlation between tooth morphology and key aspects of biomechanical behaviour in otodontids, making it difficult to frame the morphological trend of their dentitions within an adaptive scenario. We propose that this pattern most likely emerged as a non-functional by-product of heterochronic processes driven by selection towards larger body sizes.", "keyphrases": ["dentition", "shark", "otodontidae"]}
{"id": "paleo.009093", "title": "Hydroxymethanesulfonate from Volcanic Sulfur Dioxide: A \u201cMineral\u201d Reservoir for Formaldehyde and Other Simple Carbohydrates in Prebiotic Chemistry", "abstract": "Abstract While formaldehyde (HCHO) was likely generated in Earth's prebiotic atmosphere by ultraviolet light, electrical discharge, and/or volcano-created lightning, HCHO could not have accumulated in substantial amounts in prebiotic environments, including those needed for prebiotic processes that generate nucleosidic carbohydrates. HCHO at high concentrations in alkaline solutions self-reacts in the Cannizzaro reaction to give methanol and formate, neither having prebiotic value. Here, we explore the possibility that volcanic sulfur dioxide (SO2) might have generated a reservoir for Hadean HCHO by a reversible reaction with HCHO to give hydroxymethanesulfonate (HMS). We show that salts of HMS are stable as solids at 90\u00b0C and do not react with themselves in solution, even at high (>8 M) concentrations. This makes them effective stores of HCHO, since the reverse reaction slowly delivers HCHO back into an environment where it can participate in prebiotically useful reactions. Specifically, we show that in alkaline borate solutions, HCHO derived from HMS allows formation of borate-stabilized carbohydrates as effectively as free HCHO, without losing material to Cannizzaro products. Further, we show that SO2 can perform similar roles for glycolaldehyde and glyceraldehyde, two intrinsically unstable carbohydrates that are needed by various models as precursors for RNA building blocks. Zircons from the Hadean show that the Hadean mantle likely provided volcanic SO2 at rates at least as great as the rates of atmospheric HCHO generation, making the formation of Hadean HMS essentially unavoidable. Thus, hydroxymethylsulfonate adducts of formaldehyde, glycolaldehyde, and glyceraldehyde, including the less soluble barium, strontium, and calcium salts, are likely candidates for prebiotically useful organic minerals on early Earth.", "keyphrases": ["volcanic sulfur dioxide", "mineral", "reaction", "hydroxymethanesulfonate"]}
{"id": "10.1111/j.1475-4983.2006.00606.x", "title": "THE SYSTEMATICS AND PHYLOGENETIC RELATIONSHIPS OF VETULICOLIANS", "abstract": "Abstract:\u2002 Vetulicolians have variously been considered to be unusual arthropods, stem\u2010group deuterostomes or relatives of the tunicates. They are known from a number of Cambrian Lagerst\u00e4tten, and are particularly diverse in the Chengjiang biota of Yunnan Province, China. We recognize two classes, Vetulicolida and Banffozoa, which together form a monophyletic group. Within the Chinese collections we also identify two new species and recognize one new genus: Vetulicola monile sp. nov. and Bullivetula variola gen. et sp. nov. The evidence from new and previously described specimens is used to undertake a phylogenetic analysis and to evaluate a range of hypotheses for the affinities of vetulicolians. Given the difficulties of interpreting features in enigmatic fossils and the apparently contradictory set of characters possessed by vetulicolians, it is not possible on current evidence to reach an unequivocal conclusion regarding the phylogenetic position of the group. One possibility is that they are a sister group of arthropods that lost limbs but gained gill structures analogous to those of deuterostomes, but several features remain unexplained by this model. If they are protostomes, a more generally parsimonious position is close to the kinorhynchs. An alternative is that they are deuterostomes, although a placement at the base of the clade is not supported by the evidence. If they are deuterostomes, it is more likely that they are close to the tunicates.", "keyphrases": ["vetulicolian", "relative", "phylogenetic analysis", "protostome", "kinorhynch"]}
{"id": "10.1111/j.1502-3931.1986.tb00722.x", "title": "Taphonomic versus ecologic controls on taxonomic relative abundance patterns in tempestites", "abstract": "Evaluation of taphonomic sample bias in tempestites is an important prerequisite for paleoecologic analysis in storm-dominated shelf settings. Data from tempestites in the Upper Cambrian Bison Creek Formation of southern Alberta indicate that size, sorting greatly influences trilobite relative abundance patterns. Shifts in relative abundances of taxa both within and between beds are matched by changes in trilobite size. That is, collections fall into two intergrading types of assemblage which are dominated by taxa which reach large and small adult sizes, respectively. These shifts in dominance are interpreted as taphonomic variability within a single trilobite biofacies. Biofacies differentiation is expressed as abrupt changes in relative abundance patterns that are independent of trilobite size. Qualitative general models for size-sorting in tempestites are developed. Size-sorting in graded tempestites produces vertical shifts in relative abundances of taxa that mimic those expected in short-term autogenic ecologic succession. Size-sorting between beds in a single section could lead to an overestimation of the number of biofacies present. Size-sorting between proximal and distal portions of a depth gradient might generate abundance patterns that mimic those expected for \u2018depth-related communities\u2019, even in the complete absence of any underlying ecologic differentiation. The models represent taphonomic null hypotheses which must be rejected prior to making paleoecologic inferences in storm-dominated shelf environments. 0 Taphonomy, tempestites, Trilobita, Upper Cambrian, paleoecology.", "keyphrases": ["control", "relative abundance pattern", "tempestite"]}
{"id": "10.1126/science.1190612", "title": "Deepwater Formation in the North Pacific During the Last Glacial Termination", "abstract": "Switching Basins Most of the densest, deepest water at the bottom of the oceans comes from two regions, the North Atlantic and the circum-Antarctic. Have other regions been able to produce significant quantities of deep water in the past? For decades, researchers have looked, with limited success, for evidence of deepwater formation in the North Pacific since the time of the Last Glacial Maximum, about 23,000 years ago. Okazaki et al. (p. 200) combine published observational evidence from the North Pacific with model simulations to suggest that deep water did form in the North Pacific during the early part of the Last Glacial Termination, between about 17,500 and 15,000 years ago. The switch between deep-water formation in the North Atlantic and the North Pacific is likely to have had an important effect on heat transport and climate. The Atlantic was not the only ocean in the Northern Hemisphere in which deep water formed during the last deglaciation. Between ~17,500 and 15,000 years ago, the Atlantic meridional overturning circulation weakened substantially in response to meltwater discharges from disintegrating Northern Hemispheric glacial ice sheets. The global effects of this reorganization of poleward heat flow in the North Atlantic extended to Antarctica and the North Pacific. Here we present evidence from North Pacific paleo surface proxy data, a compilation of marine radiocarbon age ventilation records, and global climate model simulations to suggest that during the early stages of the Last Glacial Termination, deep water extending to a depth of ~2500 to 3000 meters was formed in the North Pacific. A switch of deepwater formation between the North Atlantic and the North Pacific played a key role in regulating poleward oceanic heat transport during the Last Glacial Termination.", "keyphrases": ["north pacific", "glacial termination", "deglaciation", "deepwater formation"]}
{"id": "10.1080/03115518.2013.743709", "title": "Postcranial skeleton of Cricosaurus araucanensis (Crocodyliformes: Thalattosuchia): morphology and palaeobiological insights", "abstract": "Herrera, Y., Fern\u00e1ndez, M.S. & Gasparini, Z., 2013. Postcranial skeleton of Cricosaurus araucanensis (Crocodyliformes: Thalattosuchia): morphology and palaeobiological insights. Alcheringa 37, 1\u201314. ISSN 0311-5518. The metriorhynchid crocodyliform Cricosaurus araucanensis (Gasparini & Dellap\u00e9) has been documented from Tithonian (Upper Jurassic) strata of the Vaca Muerta Formation exposed in the Neuqu\u00e9n Basin, northwest Patagonia, Argentina. Postcranial components of this species were mentioned but not described in the original analysis. Subsequently, other authors described the forelimbs. The postcranial elements of metriorhynchids are poorly documented in comparison with their skulls, but new data from C. araucanensis reveal delayed ossification of the caudal neurocentral sutures indicating skeletal paedomorphosis affecting not only the appendicular skeleton but also the posterior region of the vertebral column. The morphology of the caudal region (transverse processes of the first caudal vertebrae ventrally deflected) and the reduction in the femur of the fourth trochanter suggest a reduction of the hypaxial musculature allowing increased epaxial musculature. This pattern of musculoskeletal arrangement is consistent with the swimming style and propulsion by lateral undulation of the tail, as proposed by previous authors. Yanina Herrera [yaninah@fcnym. unlp.edu.ar], Marta S. Fern\u00e1ndez [martafer@fcnym.unlp.edu.ar] and Zulma Gasparini [zgaspari@fcnym.unlp.edu.ar], Divisi\u00f3n Paleontolog\u00eda Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n, W1900FWA La Plata, Argentina, CONICET. Received 23.7.2012; revised 16.10.2012; accepted 22.10.2012.", "keyphrases": ["cricosaurus araucanensis", "crocodyliforme", "skull", "postcranial skeleton"]}
{"id": "10.1111/j.1475-4983.2010.00983.x", "title": "A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of Leptosuchus Case, 1922", "abstract": "Abstract:\u2002 Leptosuchus Case, 1922 (Reptilia: Phytosauria) from the Late Triassic of the American West is represented by many specimens. Here, I present complete morphological descriptions of the skull material of a new taxon from the Sonsela Member (Chinle Formation) of Petrified Forest National Park, Arizona, with the first rigorous phylogenetic analysis focused on the interrelationships of Leptosuchus. The new taxon is recovered as the sister taxon to Pseudopalatinae. It possesses one unambiguous synapomorphy (the \u2018septomaxillae\u2019 form part of the lateral borders of the nares) and shares the presence of a subsidiary opisthotic process with Pseudopalatinae. The new taxon does not fall within the restricted clade Leptosuchus. In my analysis, the previously proposed, but undemonstrated, sister taxon relationship between Angistorhinus and Rutiodon is not supported, Paleorhinus is recovered as paraphyletic, and a subset of taxa traditionally included within Leptosuchus are found to be more closely related to Pseudopalatinae, rendering Leptosuchus paraphyletic. \u2018Leptosuchus\u2019adamanensis emerges as sister taxon to Smilosuchus gregorii and is here referred to as Smilosuchus adamanensis nov. comb., and \u2018Machaeroprosopus\u2019lithodendrorum is also transferred to Smilosuchus lithodendrorum nov. comb. Documentation of the variation present within Phytosauria, and specifically within Leptosuchus sensu lato, demonstrates higher diversity within Phytosauria than previously appreciated and places the character states previously proposed for Pseudopalatinae into a broader context of shared characters.", "keyphrases": ["new taxon", "late triassic", "chinle formation"]}
{"id": "paleo.005491", "title": "A new taxon of phytosaur (Archosauria: Pseudosuchia) from the Late Triassic (Norian) Sonsela Member (Chinle Formation) in Arizona, and a critical reevaluation of Leptosuchus Case, 1922", "abstract": "Abstract:\u2002 Leptosuchus Case, 1922 (Reptilia: Phytosauria) from the Late Triassic of the American West is represented by many specimens. Here, I present complete morphological descriptions of the skull material of a new taxon from the Sonsela Member (Chinle Formation) of Petrified Forest National Park, Arizona, with the first rigorous phylogenetic analysis focused on the interrelationships of Leptosuchus. The new taxon is recovered as the sister taxon to Pseudopalatinae. It possesses one unambiguous synapomorphy (the \u2018septomaxillae\u2019 form part of the lateral borders of the nares) and shares the presence of a subsidiary opisthotic process with Pseudopalatinae. The new taxon does not fall within the restricted clade Leptosuchus. In my analysis, the previously proposed, but undemonstrated, sister taxon relationship between Angistorhinus and Rutiodon is not supported, Paleorhinus is recovered as paraphyletic, and a subset of taxa traditionally included within Leptosuchus are found to be more closely related to Pseudopalatinae, rendering Leptosuchus paraphyletic. \u2018Leptosuchus\u2019adamanensis emerges as sister taxon to Smilosuchus gregorii and is here referred to as Smilosuchus adamanensis nov. comb., and \u2018Machaeroprosopus\u2019lithodendrorum is also transferred to Smilosuchus lithodendrorum nov. comb. Documentation of the variation present within Phytosauria, and specifically within Leptosuchus sensu lato, demonstrates higher diversity within Phytosauria than previously appreciated and places the character states previously proposed for Pseudopalatinae into a broader context of shared characters.", "keyphrases": ["new taxon", "late triassic", "chinle formation"]}
{"id": "10.1371/journal.pone.0213854", "title": "Recurrent palaeo-wildfires in a Cisuralian coal seam: A palaeobotanical view on high-inertinite coals from the Lower Permian of the Paran\u00e1 Basin, Brazil", "abstract": "Distribution and abundance of charcoal in coal seams (in form of pyrogenic macerals of the inertinites group) have been considered as a reliable tool to interpret the local and regional palaeo-wildfire regimes in peat-forming depositional environments. Although the occurrence of inertinites is globally well documented for the Late Palaeozoic, the description of palaeobotanical evidence concerning the source plants of such charcoal is so far largely missing. In the present study, we provide the first detailed analysis of macro-charcoal preserved in the Barro Branco coal seam, Rio Bonito Formation, Cisuralian of the Paran\u00e1 Basin, Santa Catarina State, Brazil. Charcoal, in form of macro-charcoal and inertinites, was documented in all the six coal-bearing strata that compose the succession, confirming the occurrence of recurrent palaeo-wildfires during its deposition. Reflectance values indicated a mean charring temperature reaching ~515\u00b0C (and up to 1,045\u00b0C in excess) and the macro-charcoal exhibits anatomical features of secondary xylem of Agathoxylon. Combination of results derived from palaeobotanical and petrological data demonstrates that gymnosperm-dominated vegetation was repeatedly submitted to fire events and reinforced the hypothesis that Gondwanan mires were high-fire systems during the Cisuralian.", "keyphrases": ["palaeo-wildfire", "coal seam", "paran\u00e1 basin", "palaeoenvironmental study"]}
{"id": "10.1080/03014223.2005.9517779", "title": "Sequence stratigraphy of the Nukumaruan Stratotype (Pliocene\u2010Pleistocene, c. 2.08\u20131.63 Ma), Wanganui Basin, New Zealand", "abstract": "Abstract Late Pliocene to Early Pleistocene (c. 2.08\u20141.63 Ma) strata exposed in coastal cliffs along Nukumaru and Ototoka beaches near Wanganui, between the top of the Nukumaru Limestone and the base of the Butlers Shell Conglomerate, comprise 11 depositional sequences of a total thickness of c. 86 m. The sequences consist predominantly of silicilclastic shoreline facies. Non\u2010marine facies (including palaeosols), and a variety of shallow\u2010marine shellbed facies, are also represented. Patterns in facies composition and sequence architecture reveal three sequence motifs (Maxwell, Nukumaru, and Birdgrove) that represent progressively increasing maximum palaeowater depths within a broadly basin\u2010margin palaeogeographic setting. The sequence motif changes systematically up section and records a lower order tectonic influence on accommodation that has modulated the stacking patterns of individual sequences. Correlation of the sequences with oxygen isotope stages 77\u201357 is achieved using the basin\u2010wide Ototoka tephra, and indicates that the sequences accumulated in response to obliquity driven (41 k.y. duration) glacio\u2010eustatic sea\u2010level oscillations. Correlation of the Nukumaru coast sequences with other sections along basin strike, and the global oxygen isotope record indicates that (i) 500 k.y. (\u03b418O stages MIS 56\u201334) is missing at the unconformity between the Nukumaruan and overlying Castlecliffian stratotypes on the Wanganui coast, and (ii) the Pliocene\u2010Pleistocene boundary lies within sequence NC7 at the base of the Lower Maxwell Formation.", "keyphrases": ["wanganui basin", "depositional sequence", "back-arc basin"]}
{"id": "10.1080/03115518.2015.1079692", "title": "Revision and two new species of Itaphlebia (Nannochoristidae: Mecoptera) from the Middle Jurassic of Inner Mongolia, China", "abstract": "Cao, Y., Shih, C., Bashkuev, A. & Ren, D., September 2015. Revision and two new species of Itaphlebia (Nannochoristidae: Mecoptera) from the Middle Jurassic of Inner Mongolia, China. Alcheringa 40, XX\u2013XX. ISSN 0311-5518. Two new species of Itaphlebia Sukatsheva, 1985, Itaphlebia longiovata and I. amoena (Nannochoristidae Tillyard, 1917), are described and illustrated from the Middle Jurassic Jiulongshan Formation of Daohugou, Inner Mongolia, China. Previously described Middle Jurassic nannochoristid genera, Chrysopanorpa Ren in Ren et al., 1995 and Protochoristella Sun, Ren & Shih, 2007b, together with Stylopanorpodes and Netropanorpodes Sun, Ren & Shih, 2007a (originally assigned to Mesopanorpodidae) are revised and considered to be synonyms of Itaphlebia. The following tentative species synonymies are proposed: Protochoristella formosa and Stylopanorpodes eurypterus = Itaphlebia ruderalis (Ren in Ren et al., 1995), comb. nov.; Netropanorpodes sentosus = I. jeniseica Novokshonov, 1997a, syn. nov.; and Protochoristella polyneura = I. multa Novokshonov, 1997a, syn. nov. Netropanorpodes decorosus is transferred to Itaphlebia. These new species, new material and the new combinations broaden the diversity of the Itaphlebia in mid-Mesozoic ecosystems and provide new characters enabling amendment of the generic diagnosis. YiZi Cao [easycaoyinzi@aliyun.com], ChungKun Shih [chungkun.shih@gmail.com] and Dong Ren [rendong@mail.cnu.edu.cn], College of Life Sciences, Capital Normal University, Xisanhuanbeilu 105, Haidian District, Beijing, PR China 100048; Alexei Bashkuev [fossilmec@gmail.com], Borissiak Paleontological Institute, Russian Academy of Sciences, Profsoyuznaya st. 123, Moscow 117997, Russia.", "keyphrases": ["itaphlebia", "nannochoristidae", "mecoptera"]}
{"id": "10.5710/AMGH.03.03.2020.3268", "title": "New Proterotheriids from the Middle Miocene of Quebrada Honda, Bolivia, and Body Size and Diversity Trends in Proterotheriid and Macraucheniid Litopterns (Mammalia)", "abstract": "Abstract. In this work, we describe two new species of proterotheriid litopterns, Olisanophus riorosarioensis gen. et sp. nov. and Olisanophus akilachuta sp. nov. from the middle Miocene (Laventan SALMA) of Quebrada Honda, Bolivia. When incorporated into a recently published phylogenetic analysis (40 taxa; 92 characters), they plot as sister taxa, partially supported by their connected metaconule and protocone on M3. Additionally, we revise the taxonomy of two contemporaneous proterotheriids from La Venta, Colombia. \u2018Prolicaphrium' sanalfonensis is reassigned to Mesolicaphrium gen. nov., with a prominent protocone on M3 as an autapomorphy of the genus. We revalidate the genus Neodolodus for Neodolodus colombianus, a species referred to \u2018Prothoatherium' or Lambdaconus by previous authors. We used the paleotree R package to examine evolutionary trends in diversity and body size (using m1 length as a proxy) in proterotheriid and macraucheniid litopterns in a phylogenetic context. Proterotheriids were more diverse in the Paleogene than their fossil record indicates; their diversity peaked in the early Miocene and gradually declined until the Pleistocene. Macraucheniids experienced two peaks in diversity, in the early and late Miocene, but were still fairly diverse in the Pleistocene, unlike proterotheriids. Multiple proterotheriid lineages became larger during the Paleogene, but body size was roughly static during the Neogene, with no obvious link between phylogeny and size. Macraucheniids can be grouped into three size classes that are phylogenetically conserved and roughly correspond temporally to Eocene (small Polymorphis spp.), Miocene\u2013Pliocene (medium-sized \u2018cramaucheniines\u2019 and early macraucheniines, e.g., Theosodon, Promacrauchenia), and Pleistocene (large macraucheniines, e.g., Macrauchenia) species.", "keyphrases": ["proterotheriid", "middle miocene", "body size"]}
{"id": "10.1080/00379271.2010.10697656", "title": "Fossil carabids from Baltic amber -II - A new subgenus of Bembidion Latreille 1802 (Coleoptera: Carabidae: Bembidiini)", "abstract": "Abstract Bembidion (Archaeophilochthus) christelae a new subgenus and species belonging to the tribe Bembidiini (Coleoptera: Carabidae: Trechinae) preserved in a piece of Baltic amber (Eocene) is described. A comparison with recent fauna is made, and paleobiology of the species is hypothetized.", "keyphrases": ["baltic amber", "coleoptera", "carabidae"]}
{"id": "10.1126/science.1253958", "title": "Neandertal roots: Cranial and chronological evidence from Sima de los Huesos", "abstract": "Neandertal ancestors from Pleistocene Spain The Sima de los Huesos site in Atapuerca, northern Spain, is a rich source of fossil hominin specimens. The site has now yielded further skull specimens that illuminate patterns of human evolution in Europe nearly half a million years ago. Arsuaga et al. studied 17 crania, including 7 that are new specimens and 6 that are more complete than before (see the Perspective by Hublin). This assemblage of specimens reveals the cranial, facial, and dental features of the Atapuerca hominins, which allows more precise evolutionary positioning of these Neandertal ancestors. Science, this issue p. 1358; see also p. 1338 Seventeen skulls from at least 430 thousand years ago illuminate hominin evolutionary patterns in Pleistocene Europe. [Also see Perspective by Hublin] Seventeen Middle Pleistocene crania from the Sima de los Huesos site (Atapuerca, Spain) are analyzed, including seven new specimens. This sample makes it possible to thoroughly characterize a Middle Pleistocene hominin paleodeme and to address hypotheses about the origin and evolution of the Neandertals. Using a variety of techniques, the hominin-bearing layer could be reassigned to a period around 430,000 years ago. The sample shows a consistent morphological pattern with derived Neandertal features present in the face and anterior vault, many of which are related to the masticatory apparatus. This suggests that facial modification was the first step in the evolution of the Neandertal lineage, pointing to a mosaic pattern of evolution, with different anatomical and functional modules evolving at different rates.", "keyphrases": ["sima", "neandertal ancestor", "los huesos site", "phenotype"]}
{"id": "paleo.004529", "title": "Sauropodomorph dinosaur trackways from the Fleming Fjord Formation of East Greenland: evidence for Late Triassic sauropods", "abstract": "Sauropodomorph dinosaur trackways from the Fleming Fjord Formation of East Greenland: Evidence for Late Triassic sauropods. L.B. 2017. Sauropodomorph dinosaur trackways from the Fleming Fjord Formation of East Greenland: Evidence for Late Triassic sauropods. Acta Palae onto-logica Polonica 62 (4): 833\u2013843. The Late Triassic (Norian\u2013early Rhaetian) Fleming Fjord Formation of central East Greenland preserves a diverse fossil fauna, including both body and trace fossils. Trackways of large quadrupedal archosaurs, although already reported in 1994 and mentioned in subsequent publications, are here described and figured in detail for the first time, based on photogrammetric data collected during fieldwork in 2012. Two trackways can be referred to Eosauropus , while a third, bipedal trackway may be referred to Evazoum , both of which have been considered to represent sauropodomorph dinosaur tracks. Both the Evazoum and the Eosauropus trackways are distinctly larger than other trackways referred to the respective ichnogenera. The trackmaker of the best preserved Eosauropus trackway is constrained using a synapo-morphy-based approach. The quadrupedal posture, the entaxonic pes structure, and five weight-bearing digits indicate a derived sauropodiform trackmaker. Other features exhibited by the tracks, including the semi-digitigrade pes and the laterally deflected unguals, are commonly considered synapomorphies of more exclusive clades within Sauropoda. The present trackway documents an early acquisition of a eusauropod-like pes anatomy while retaining a well-developed claw on pedal digit IV, which is reduced in eusauropods. Although unequivocal evidence for sauropod dinosaurs is no older than the Early Jurassic, the present trackway provides evidence for a possible Triassic origin of the group.", "keyphrases": ["fleming fjord formation", "east greenland", "track", "sauropodomorph dinosaur trackway"]}
{"id": "paleo.008865", "title": "Oviraptorosaur Tail Forms and Functions", "abstract": "Oviraptorosaur caudal osteology is unique among theropods and is characterized by posteriorly persistent and exceptionally wide transverse processes, anteroposteriorly short centra, and a high degree of flexibility across the pre-pygostyle vertebral series. Three-dimensional digital muscle reconstructions reveal that, while oviraptorosaur tails were reduced in length relative to the tails of other theropods, they were muscularly robust. Despite overall caudal length reduction, the relative size of the M. caudofemoralis in most oviraptorosaurs was comparable with those of other non-avian theropods. The discovery of a second Nomingia specimen with a pygostyle confirms that the fused terminal vertebrae of the type specimen were not an abnormality. New evidence shows that pygostyles were also present in the oviraptorosaurs Citipati and Conchoraptor. Based on the observed osteological morphology and inferred muscle morphology, along with the recognition that many members of the group probably sported broad tail-feather fans, it is postulated that oviraptorosaur tails were uniquely adapted to serve as dynamic intraspecific display structures. Similarities, including a reduced vertebral series and a terminal pygostyle, between the tails of oviraptorosaurs and the tails of theropods widely accepted as basal members of the Avialae, appear to be convergences.", "keyphrases": ["tail", "theropod", "pygostyle", "oviraptorosaur"]}
{"id": "10.1017/S1089332600002837", "title": "Burgess Shale-type Preservation and its Distribution in Space and Time", "abstract": "Burgess Shale-type fossil assemblages provide a unique record of animal life in the immediate aftermath of the so-called \u201cCambrian explosion.\u201d While most soft-bodied faunas in the rock record were conserved by mineral replication of soft tissues, Burgess Shale-type preservation involved the conservation of whole assemblages of soft-bodied animals as primary carbonaceous remains, often preserved in extraordinary anatomical detail. Burgess Shale-type preservation resulted from a combination of influences operating at both local and global scales that acted to drastically slow microbial degradation in the early burial environment, resulting in incomplete decomposition and the conservation of soft-bodied animals, many of which are otherwise unknown from the fossil record. While Burgess Shale-type fossil assemblages are primarily restricted to early and middle Cambrian strata (Series 2\u20133), their anomalous preservation is a pervasive phenomenon that occurs widely in mudstone successions deposited on multiple paleocontinents. Herein, circumstances that led to the preservation of Burgess Shale-type fossils in Cambrian strata worldwide are reviewed. A three-tiered rank classification of the more than 50 Burgess Shale-type deposits now known is proposed and is used to consider the hierarchy of controls that regulated the operation of Burgess Shale-type preservation in space and time, ultimately determining the total number of preserved taxa and the fidelity of preservation in each deposit. While Burgess Shale-type preservation is a unique taphonomic mode that ultimately was regulated by the influence of global seawater chemistry upon the early diagenetic environment, physical depositional (biostratinomic) controls are shown to have been critical in determining the total number of taxa preserved in fossil assemblages, and hence, in regulating many of the important differences among Burgess Shale-type deposits.", "keyphrases": ["space", "soft-bodied faunas", "burgess shale-type preservation"]}
{"id": "10.1144/SP379.11", "title": "\u2018Proterosuchia\u2019: the origin and early history of Archosauriformes", "abstract": "Abstract The earliest history of Archosauriformes is mainly represented by members of Proterosuchidae and Erythrosuchidae, which are known worldwide from latest Permian to Middle Triassic beds. These two groups were historically combined within \u2018Proterosuchia\u2019, with approximately 30 nominal species. Two morphotypes have been recognized among proterosuchians: proterosuchids with a generally more sprawling gait and elongated and low skulls with an overhanging premaxilla, and the more heavily built erythrosuchids, with a probably less sprawling gait and large, presumably hypercarnivorous, skulls. The systematics of \u2018Proterosuchia\u2019 was relatively chaotic throughout most of the twentieth century, but currently there exists consensus regarding the non-monophyly of proterosuchians and their phylogenetic position outside all other archosauriforms. In contrast, the delimitation and taxonomic content of Proterosuchidae and Erythrosuchidae remain unstable. Few studies of proterosuchian palaeobiology have been carried out. Current lines of evidence favour a predominantly terrestrial lifestyle for proterosuchians. Limb bone histology indicates rapid continuous growth rates in Proterosuchus and Erythrosuchus before reaching sexual maturity. A better knowledge of proterosuchian anatomy, systematics, evolution and ecology is important for advancing understanding of the origin and early radiation of Archosauriformes and the patterns of biotic recovery following the Permo-Triassic mass extinction event. There remains much research to be carried out in proterosuchian palaeobiology.", "keyphrases": ["proterosuchia", "early history", "archosauriformes", "erythrosuchidae"]}
{"id": "paleo.011850", "title": "Bayesian Total-Evidence Dating Reveals the Recent Crown Radiation of Penguins", "abstract": "Abstract The total\u2010evidence approach to divergence time dating uses molecular and morphological data from extant and fossil species to infer phylogenetic relationships, species divergence times, and macroevolutionary parameters in a single coherent framework. Current model\u2010based implementations of this approach lack an appropriate model for the tree describing the diversification and fossilization process and can produce estimates that lead to erroneous conclusions. We address this shortcoming by providing a total\u2010evidence method implemented in a Bayesian framework. This approach uses a mechanistic tree prior to describe the underlying diversification process that generated the tree of extant and fossil taxa. Previous attempts to apply the total\u2010evidence approach have used tree priors that do not account for the possibility that fossil samples may be direct ancestors of other samples, that is, ancestors of fossil or extant species or of clades. The fossilized birth\u2010death (FBD) process explicitly models the diversification, fossilization, and sampling processes and naturally allows for sampled ancestors. This model was recently applied to estimate divergence times based on molecular data and fossil occurrence dates. We incorporate the FBD model and a model of morphological trait evolution into a Bayesian total\u2010evidence approach to dating species phylogenies. We apply this method to extant and fossil penguins and show that the modern penguins radiated much more recently than has been previously estimated, with the basal divergence in the crown clade occurring at \u223c12.7 Ma and most splits leading to extant species occurring in the last 2 myr. Our results demonstrate that including stem\u2010fossil diversity can greatly improve the estimates of the divergence times of crown taxa. The method is available in BEAST2 (version 2.4) software www.beast2.org with packages SA (version at least 1.1.4) and morph\u2010models (version at least 1.0.4) installed.", "keyphrases": ["total-evidence dating", "conclusion", "sampled ancestor", "molecular data", "paleontology"]}
{"id": "paleo.008129", "title": "Native biodiversity collapse in the eastern Mediterranean", "abstract": "Global warming causes the poleward shift of the trailing edges of marine ectotherm species distributions. In the semi-enclosed Mediterranean Sea, continental masses and oceanographic barriers do not allow natural connectivity with thermophilic species pools: as trailing edges retreat, a net diversity loss occurs. We quantify this loss on the Israeli shelf, among the warmest areas in the Mediterranean, by comparing current native molluscan richness with the historical one obtained from surficial death assemblages. We recorded only 12% and 5% of historically present native species on shallow subtidal soft and hard substrates, respectively. This is the largest climate-driven regional-scale diversity loss in the oceans documented to date. By contrast, assemblages in the intertidal, more tolerant to climatic extremes, and in the cooler mesophotic zone show approximately 50% of the historical native richness. Importantly, approximately 60% of the recorded shallow subtidal native species do not reach reproductive size, making the shallow shelf a demographic sink. We predict that, as climate warms, this native biodiversity collapse will intensify and expand geographically, counteracted only by Indo-Pacific species entering from the Suez Canal. These assemblages, shaped by climate warming and biological invasions, give rise to a \u2018novel ecosystem\u2019 whose restoration to historical baselines is not achievable.", "keyphrases": ["mediterranean", "ecosystem", "native biodiversity collapse"]}
{"id": "10.1080/01916122.2014.961664", "title": "The Middle Jurassic Palynology of the Daohugou Area, Inner Mongolia, China, and Its Implications for Palaeobiology and Palaeogeography", "abstract": "Although abundant palaeontological discoveries have been documented in the Daohugou area in Chifeng City, Inner Mongolia, China, no record of the palynoflora has been reported previously. We collected palynological samples from the same level as megafossil plants, and conducted a detailed taxonomic analysis of the pollen and spores in order to augment the megafossil record, to extend documentation of the Middle Jurassic palynoflora, and to examine implications for palaeogeography, palaeoecology and palaeoclimate in north China during the Jurassic. Forty-four genera and 87 species of palynomorphs were identified. Pollen of gymnosperms dominates numerically, followed by spores of pteridophytes. Most taxa, including bisaccate pollen of conifers, monosulcate pollen of Cycadales, Bennettitales or Ginkgoales, along with Cyathidites, Deltoidospora, Granulatisporites, Osmundacidites and Classopollis, are common elements known elsewhere during the Jurassic. Based on comparisons with similar palyno-assemblages in the Jurassic of China, the age of the Daohugou locality is interpreted to be late Middle Jurassic. According to the palaeobotanical and palaeopalynological information, the Daohugou flora is attributed to the warm-temperate to medium temperate zone with seasonal change. By studying the ecological and climatic preferences of the main plant groups, five types of palaeolandscape in the Jurassic of Daohugou are proposed: (1) mesic upland (Pinaceae, Podocarpaceae, Czekanowskiales and Bennettitales), (2) mesic lowland (Pinaceae, Podocarpaceae, Ginkgoales, Czekanowskiales and Cycadales, together with some hygrophilous bryophytes, lycophytes and ferns), (3) dry upland (Czekanowskiales), (4) dry lowland (Czekanowskiales and Cheirolepidiaceae) and (5) waterside (plants growing along streams or near lakes, including bryophytes, lycophytes, ferns and probably some pteridosperms). According to the plant assemblage, the Daohugou flora corresponds to that of the Middle Jurassic Northern Floristic Province of China, which experienced a transition from a humid, warm climate to a hotter climate with seasonal drought.", "keyphrases": ["daohugou area", "inner mongolia", "palaeogeography"]}
{"id": "10.1073/pnas.0800560105", "title": "Younger Dryas \u201cblack mats\u201d and the Rancholabrean termination in North America", "abstract": "Of the 97 geoarchaeological sites of this study that bridge the Pleistocene-Holocene transition (last deglaciation), approximately two thirds have a black organic-rich layer or \u201cblack mat\u201d in the form of mollic paleosols, aquolls, diatomites, or algal mats with radiocarbon ages suggesting they are stratigraphic manifestations of the Younger Dryas cooling episode 10,900 B.P. to 9,800 B.P. (radiocarbon years). This layer or mat covers the Clovis-age landscape or surface on which the last remnants of the terminal Pleistocene megafauna are recorded. Stratigraphically and chronologically the extinction appears to have been catastrophic, seemingly too sudden and extensive for either human predation or climate change to have been the primary cause. This sudden Rancholabrean termination at 10,900 \u00b1 50 B.P. appears to have coincided with the sudden climatic switch from Aller\u00f8d warming to Younger Dryas cooling. Recent evidence for extraterrestrial impact, although not yet compelling, needs further testing because a remarkable major perturbation occurred at 10,900 B.P. that needs to be explained.", "keyphrases": ["black mat", "rancholabrean termination", "younger dryas"]}
{"id": "paleo.004054", "title": "Climate and vegetation change during the Upper Siwalik-a study based on the palaeobotanical record of the eastern Himalaya", "abstract": "Today, Northeastern India receives some of the highest annual rainfall totals globally. The major portion of annual precipitation in this region falls during the Indian Summer Monsoon season (June-September); however, this region also receives a significant amount of rainfall during the pre-monsoon season (March-May). Here, we quantitatively reconstruct the climate of the Upper Siwalik subgroup, eastern Himalayan region, based on fossil assemblages using the Coexistence Approach (CA). The age of the fossil assemblage is considered to be late Pliocene-early Pleistocene. Data reconstructed for the present-day and past premonsoon rainfall in Northeastern India indicate an increasing trend since the late Miocene-early Pliocene. During the late Pliocene-early Pleistocene (Upper Siwalik), the temperature seasonality between warm (27-28.1 \u00b0C) and cold months (22-23.6 \u00b0C) was less pronounced compared with present-day warm (27-27.7 \u00b0C) and cold (14.8-15.4 \u00b0C) months conditions at the fossil locality. The reconstructed rainfall data indicate a monsoonal type of climate having a strong seasonality in wet and dry seasons during the deposition of the Upper Siwalik sediments. Moreover, composition of the fossil floras and reconstructed palaeoclimate suggest a vegetation shift from dominantly wet evergreen to semi-evergreen at the fossil locality, coincident with an increase in length of the dry season. The comparison of reconstructed CA data and climate modelling data of a Gelasian time slice with that of previously reconstructed climate data by using Climate Leaf Analysis Multivariate Programme (CLAMP) analysis of the late Pliocene-early Pleistocene (Upper Siwalik) fossils of the same locality provides nearly the identical result. Furthermore, all the reconstructed data indicate a monsoonal type of climate during the deposition of the Upper Siwalik sediments.\n", "keyphrases": ["rainfall", "fossil locality", "vegetation shift", "evergreen", "deciduous forest taxa"]}
{"id": "10.3389/fmars.2014.00053", "title": "New insights on early evolution of spiny-rayed fishes (Teleostei: Acanthomorpha)", "abstract": "The Acanthomorpha is the largest group of teleost fishes with about one third of extant vertebrate species. In the course of its evolution this lineage experienced several episodes of radiation, leading to a large number of descendant lineages differing profoundly in morphology, ecology, distribution and behavior. Although Acanthomorpha was recognized decades ago, we are only now beginning to decipher its large-scale, time-calibrated phylogeny, a prerequisite to test various evolutionary hypotheses explaining the tremendous diversity of this group. In this study, we provide new insights into the early evolution of the acanthomorphs and the euteleost allies based on the phylogenetic analysis of a newly developed dataset combining nine nuclear and mitochondrial gene markers. Our inferred tree is time-calibrated using 15 fossils, some of which have not been used before. While our phylogeny strongly supports a monophyletic Neoteleostei, Ctenosquamata (i.e., Acanthomorpha plus Myctophiformes), and Acanthopterygii, we find weak support (bootstrap value < 48%) for the traditionally defined Acanthomorpha, as well as evidence of non-monophyly for the traditional Paracanthopterygii, Beryciformes, and Percomorpha. We corroborate the new Paracanthopterygii sensu Miya et al. (2005) including Polymixiiformes, Zeiformes, Gadiformes, Percopsiformes, and likely the enigmatic Stylephorus chordatus. Our timetree largely agrees with other recent studies based on nuclear loci in inferring an Early Cretaceous origin for the acanthomorphs followed by a Late Cretaceous/Early Paleogene radiation of major lineages. This is in contrast to mitogenomic studies mostly inferring Jurassic or even Triassic ages for the origin of the acanthomorphs. We compare our results to those of previous studies, and attempt to address some of the issues that may have led to incongruence between the fossil record and the molecular clock studies, as well as between the different molecular timetrees.", "keyphrases": ["early evolution", "acanthomorpha", "new insight"]}
{"id": "10.1371/journal.pone.0128108", "title": "Fossil and Genetic Evidence for the Polyphyletic Nature of the Planktonic Foraminifera \"Globigerinoides\", and Description of the New Genus Trilobatus", "abstract": "Planktonic foraminifera are one of the most abundant and diverse protists in the oceans. Their utility as paleo proxies requires rigorous taxonomy and comparison with living and genetically related counterparts. We merge genetic and fossil evidence of \u201cGlobigerinoides\u201d, characterized by supplementary apertures on spiral side, in a new approach to trace their \u201ctotal evidence phylogeny\u201d since their first appearance in the latest Paleogene. Combined fossil and molecular genetic data indicate that this genus, as traditionally understood, is polyphyletic. Both datasets indicate the existence of two distinct lineages that evolved independently. One group includes \u201cGlobigerinoides\u201d trilobus and its descendants, the extant \u201cGlobigerinoides\u201d sacculifer, Orbulina universa and Sphaeroidinella dehiscens. The second group includes the Globigerinoides ruber clade with the extant G. conglobatus and G. elongatus and ancestors. In molecular phylogenies, the trilobus group is not the sister taxon of the ruber group. The ruber group clusters consistently together with the modern Globoturborotalita rubescens as a sister taxon. The re-analysis of the fossil record indicates that the first \u201cGlobigerinoides\u201d in the late Oligocene are ancestral to the trilobus group, whereas the ruber group first appeared at the base of the Miocene with representatives distinct from the trilobus group. Therefore, polyphyly of the genus \"Globigerinoides\" as currently defined can only be avoided either by broadening the genus concept to include G. rubescens and a large number of fossil species without supplementary apertures, or if the trilobus group is assigned to a separate genus. Since the former is not feasible due to the lack of a clear diagnosis for such a broad genus, we erect a new genus Trilobatus for the trilobus group (type species Globigerina triloba Reuss) and amend Globoturborotalita and Globigerinoides to clarify morphology and wall textures of these genera. In the new concept, Trilobatus n. gen. is paraphyletic and gave rise to the Praeorbulina / Orbulina and Sphaeroidinellopsis / Sphaeroidinella lineages.", "keyphrases": ["planktonic foraminifera", "globigerinoides", "new genus trilobatus", "ocean"]}
{"id": "10.1002/2015RG000512", "title": "Stable isotopes in atmospheric water vapor and applications to the hydrologic cycle", "abstract": "The measurement and simulation of water vapor isotopic composition has matured rapidly over the last decade, with long\u2010term data sets and comprehensive modeling capabilities now available. Theories for water vapor isotopic composition have been developed by extending the theories that have been used for the isotopic composition of precipitation to include a more nuanced understanding of evaporation, large\u2010scale mixing, deep convection, and kinetic fractionation. The technologies for in situ and remote sensing measurements of water vapor isotopic composition have developed especially rapidly over the last decade, with discrete water vapor sampling methods, based on mass spectroscopy, giving way to laser spectroscopic methods and satellite\u2010 and ground\u2010based infrared absorption techniques. The simulation of water vapor isotopic composition has evolved from General Circulation Model (GCM) methods for simulating precipitation isotopic composition to sophisticated isotope\u2010enabled microphysics schemes using higher\u2010order moments for water and ice size distributions. The incorporation of isotopes into GCMs has enabled more detailed diagnostics of the water cycle and has led to improvements in its simulation. The combination of improved measurement and modeling of water vapor isotopic composition opens the door to new advances in our understanding of the atmospheric water cycle, in processes ranging from the marine boundary layer, through deep convection and tropospheric mixing, and into the water cycle of the stratosphere. Finally, studies of the processes governing modern water vapor isotopic composition provide an improved framework for the interpretation of paleoclimate proxy records of the hydrological cycle.", "keyphrases": ["isotope", "water vapor", "precipitation"]}
{"id": "10.1017/s1477201905001793", "title": "Reassessment of the phylogenetic position of conulariids (?Ediacaran\u2010Triassic) within the subphylum medusozoa (phylum cnidaria)", "abstract": "Synopsis Fossil taxa of uncertain phylogenetic affinities can play a crucial role in the analysis of character evolution within major extant groups. Marques & Collins (2004) concluded that conulariids (?Ediacaran\u2010Triassic) are an extinct group of medusozoan cnidarians most closely related to Stauromedusae. However, only six of the 87 characters used by these authors can be observed in conulariid fossils. Rescoring the character states of conulariids in a conservative manner yields a new hypothesis for the phylogenetic position of conulariids, namely that they are the sister group of the scyphozoan order Coronatae rather than Stauromedusae, which is revealed as the earliest diverging lineage of Medusozoa. This new hypothesis also implies several different sequences of character evolution within Cnidaria. Specifically, the presence of a periderm completely covering the polyp in conulariids and coronates appears to be derived within Scyphozoa. Strobilation appears to be a synapomorphy uniting conulariids, Coronatae, Rhizostomeae and Semaeostomeae. This result supports the controversial interpretation of one exceptionally preserved conulariid that potentially shows that these animals produced ephyrae by strobilation. Finally, the pelagic adult medusa stage and the giant fibre nerve net appear to be features that are derived within Medusozoa.", "keyphrases": ["phylogenetic position", "ediacaran\u2010triassic", "medusozoa"]}
{"id": "10.1017/S1477201905001793", "title": "Reassessment of the phylogenetic position of conulariids (?Ediacaran\u2010Triassic) within the subphylum medusozoa (phylum cnidaria)", "abstract": "Synopsis Fossil taxa of uncertain phylogenetic affinities can play a crucial role in the analysis of character evolution within major extant groups. Marques & Collins (2004) concluded that conulariids (?Ediacaran\u2010Triassic) are an extinct group of medusozoan cnidarians most closely related to Stauromedusae. However, only six of the 87 characters used by these authors can be observed in conulariid fossils. Rescoring the character states of conulariids in a conservative manner yields a new hypothesis for the phylogenetic position of conulariids, namely that they are the sister group of the scyphozoan order Coronatae rather than Stauromedusae, which is revealed as the earliest diverging lineage of Medusozoa. This new hypothesis also implies several different sequences of character evolution within Cnidaria. Specifically, the presence of a periderm completely covering the polyp in conulariids and coronates appears to be derived within Scyphozoa. Strobilation appears to be a synapomorphy uniting conulariids, Coronatae, Rhizostomeae and Semaeostomeae. This result supports the controversial interpretation of one exceptionally preserved conulariid that potentially shows that these animals produced ephyrae by strobilation. Finally, the pelagic adult medusa stage and the giant fibre nerve net appear to be features that are derived within Medusozoa.", "keyphrases": ["phylogenetic position", "ediacaran\u2010triassic", "medusozoa"]}
{"id": "10.1371/journal.pone.0000889", "title": "Impedance-Matching Hearing in Paleozoic Reptiles: Evidence of Advanced Sensory Perception at an Early Stage of Amniote Evolution", "abstract": "Background Insights into the onset of evolutionary novelties are key to the understanding of amniote origins and diversification. The possession of an impedance-matching tympanic middle ear is characteristic of all terrestrial vertebrates with a sophisticated hearing sense and an adaptively important feature of many modern terrestrial vertebrates. Whereas tympanic ears seem to have evolved multiple times within tetrapods, especially among crown-group members such as frogs, mammals, squamates, turtles, crocodiles, and birds, the presence of true tympanic ears has never been recorded in a Paleozoic amniote, suggesting they evolved fairly recently in amniote history. Methodology/Principal Findings In the present study, we performed a morphological examination and a phylogenetic analysis of poorly known parareptiles from the Middle Permian of the Mezen River Basin in Russia. We recovered a well-supported clade that is characterized by a unique cheek morphology indicative of a tympanum stretching across large parts of the temporal region to an extent not seen in other amniotes, fossil or extant, and a braincase specialized in showing modifications clearly related to an increase in auditory function, unlike the braincase of any other Paleozoic tetrapod. In addition, we estimated the ratio of the tympanum area relative to the stapedial footplate for the basalmost taxon of the clade, which, at 23\u22361, is in close correspondence to that of modern amniotes capable of efficient impedance-matching hearing. Conclusions/Significance Using modern amniotes as analogues, the possession of an impedance-matching middle ear in these parareptiles suggests unique ecological adaptations potentially related to living in dim-light environments. More importantly, our results demonstrate that already at an early stage of amniote diversification, and prior to the Permo-Triassic extinction event, the complexity of terrestrial vertebrate ecosystems had reached a level that proved advanced sensory perception to be of notable adaptive significance.", "keyphrases": ["hearing", "advanced sensory perception", "early stage"]}
{"id": "10.1080/03115518.2016.1218246", "title": "Comments on the ophiuroid family Protasteridae and description of a new genus from the Lower Devonian of the Fox Bay Formation, Falkland Islands", "abstract": "Hunter, A.W., Rushton, A.W.A. & Stone, P., September 2016. Comments on the ophiuroid family Protasteridae and description of a new genus from the Lower Devonian of the Fox Bay Formation, Falkland Islands. Alcheringa 40, xxx\u2013xxx. ISSN 0311-5518 Asterozoan fossils are comparatively rare in Gondwana compared with Laurentia, especially in the Devonian. We examined the only fossil ophiuroid yet known from the Falkland Islands and assess its significance for the evolution of the clade. This ophiuroid, herein distinguished as a new genus and species, Darwinaster coleenbiggsae, belongs to the same suprageneric group as Protaster, which was established on a series of Middle\u2013Upper Ordovician taxa and persisted into the late Palaeozoic remarkably little changed in morphology. This single example is part of a much wider fauna that includes fossils from the Bokkeveld Group, South Africa and the Precordillera of Argentina. Existing palaeobiogeographic reconstructions confirm that these faunas once existed on contiguous terranes and characterized a distinct suite of similar palaeoenvironments within the Malvinokaffric Realm. This study reviews the existing record of Devonian asterozoans and revises Protasteridae. Aaron W. Hunter* [aaron.hunter@curtin.edu.au], Department of Applied Geology, Western Australian School of Mines, Curtin University, GPO Box U1987, Perth, WA 6845, Australia; Adrian W. A. Rushton [a.rushton@nhm.ac.uk], Department of Earth Sciences, The Natural History Museum, Cromwell Road, London SW7 5BD, UK; Philip Stone [psto@bgs.ac.uk], British Geological Survey, The Lyell Centre, Research Avenue South, Edinburgh EH14 4AP, UK. *Also affiliated with: Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK.", "keyphrases": ["ophiuroid family protasteridae", "new genus", "falkland islands", "morphology"]}
{"id": "10.5194/fr-20-245-2017", "title": "Identification of the African\u2013European Erymnochelys group (Pleurodira, Podocnemididae) in the Belgian fossil record: first finding of Eocenochelus eremberti outside its type locality", "abstract": "Abstract. An almost complete plastron, as well as several peripherals and a costal plate of a turtle from the middle Eocene of Saint-Gilles, is presented here. Although this turtle specimen was donated to the Institut royal des Sciences naturelles de Belgique (Brussels, Belgium) more than a century ago, it remained undescribed. Its study allows us to recognize the second pleurodiran in the Belgian fossil record, where, until now, the Eocene Neochelys was the only one known. The Belgian material of Neochelys is known in lower Eocene (early Ypresian) levels, but the new pleurodiran specimen comes from the middle Eocene (early Lutetian). It is the first partial articulate shell of a pleurodiran turtle recognized in Belgium, and the only member of this clade recognized in this country at specific level. The new specimen is a representative of the so-called Erymnochelys group, this lineage being known in Africa from the Upper Cretaceous to the present but in Europe only during the Eocene. It represents the first specimen of Eocenochelus eremberti identified outside its type locality, the French region of Saint-Germain-en-Laye (Yvelines, Ile-de-France), where only one specimen was found. The plastron of the Belgian individual corresponds to the most complete for this species. Its analysis allows us not only to broaden the range of paleobiogeographical distribution of Eocenochelus eremberti but also to improve the knowledge about the anatomy and variability of this taxon.", "keyphrases": ["belgian fossil record", "eocenochelus eremberti", "type locality", "eocene"]}
{"id": "10.5194/cp-14-1391-2018", "title": "Temperature seasonality in the North American continental interior during the Early Eocene Climatic Optimum", "abstract": "Abstract. Paleogene greenhouse climate equability has long been a paradox in paleoclimate research. However, recent developments in proxy and modeling methods have suggested that strong seasonality may be a feature of at least some greenhouse Earth periods. Here we present the first multi-proxy record of seasonal temperatures during the Paleogene from paleofloras, paleosol geochemistry, and carbonate clumped isotope thermometry in the Green River Basin (Wyoming, USA). These combined temperature records allow for the reconstruction of past seasonality in the continental interior, which shows that temperatures were warmer in all seasons during the peak Early Eocene Climatic Optimum and that the mean annual range of temperatures was high, similar to the modern value (\u2009\u223c\u200926\u2009\u00b0C). Proxy data and downscaled Eocene regional climate model results suggest amplified seasonality during greenhouse events. Increased seasonality reconstructed for the early Eocene is similar in scope to the higher seasonal range predicted by downscaled climate model ensembles for future high-CO2 emissions scenarios. Overall, these data and model comparisons have substantial implications for understanding greenhouse climates in general, and may be important for predicting future seasonal climate regimes and their impacts in continental regions.\n", "keyphrases": ["continental interior", "carbonate", "temperature seasonality"]}
{"id": "10.1073/pnas.1321441111", "title": "Pronounced zonal heterogeneity in Eocene southern high-latitude sea surface temperatures", "abstract": "Significance Reconstructions of ancient high-latitude climates can help to constrain the amplification of global warming in polar environments. Climate models cannot reproduce the elevated high-latitude temperature estimates in the Eocene epoch, possibly indicating problems in simulating polar climate change. Widely divergent near-Antarctic Eocene sea surface temperature (SST) estimates, however, question the evidence for extreme warmth. Our analysis of multiple temperature proxies near the Antarctic Peninsula improves intersite comparisons and indicates a substantial zonal SST gradient between the southwest Pacific and South Atlantic. Simulations of Eocene ocean temperatures imply that the formation of deep water in the southwest Pacific partly accounts for this SST gradient, suggesting that climate models underestimate Eocene SSTs in regions where the thermohaline circulation leads to relatively high temperatures. Paleoclimate studies suggest that increased global warmth during the Eocene epoch was greatly amplified at high latitudes, a state that climate models cannot fully reproduce. However, proxy estimates of Eocene near-Antarctic sea surface temperatures (SSTs) have produced widely divergent results at similar latitudes, with SSTs above 20 \u00b0C in the southwest Pacific contrasting with SSTs between 5 and 15 \u00b0C in the South Atlantic. Validation of this zonal temperature difference has been impeded by uncertainties inherent to the individual paleotemperature proxies applied at these sites. Here, we present multiproxy data from Seymour Island, near the Antarctic Peninsula, that provides well-constrained evidence for annual SSTs of 10\u201317 \u00b0C (1\u03c3 SD) during the middle and late Eocene. Comparison of the same paleotemperature proxy at Seymour Island and at the East Tasman Plateau indicate the presence of a large and consistent middle-to-late Eocene SST gradient of \u223c7 \u00b0C between these two sites located at similar paleolatitudes. Intermediate-complexity climate model simulations suggest that enhanced oceanic heat transport in the South Pacific, driven by deep-water formation in the Ross Sea, was largely responsible for the observed SST gradient. These results indicate that very warm SSTs, in excess of 18 \u00b0C, did not extend uniformly across the Eocene southern high latitudes, and suggest that thermohaline circulation may partially control the distribution of high-latitude ocean temperatures in greenhouse climates. The pronounced zonal SST heterogeneity evident in the Eocene cautions against inferring past meridional temperature gradients using spatially limited data within given latitudinal bands.", "keyphrases": ["eocene", "sea surface temperature", "uncertainty"]}
{"id": "10.1080/02724634.2011.627074", "title": "A comprehensive taxonomic revision of Dicynodon (Therapsida, Anomodontia) and its implications for dicynodont phylogeny, biogeography, and biostratigraphy", "abstract": "ABSTRACT The dicynodont wastebasket genus Dicynodon is revised following a comprehensive review of nominal species. Most nominal species of Dicynodon pertain to other well-known dicynodont genera, especially Oudenodon and Diictodon. Of the Karoo Permian species that are referable to \u201cDicynodon\u201d sensu lato, we recognize four common, valid morphospecies: Dicynodon lacerticeps, D. leoniceps, D. woodwardi, and Dinanomodon gilli, comb. nov. Eleven additional species of \u201cDicynodon\u201d are recognized worldwide: D. alticeps, D. amalitzkii, D. bathyrhynchus, D. benjamini, D. bogdaensis, D. huenei, D. limbus, D. sinkianensis, D. traquairi, D. trautscholdi, and D. vanhoepeni. Morphometric analysis of D. lacerticeps and D. leoniceps specimens recovers statistically significant separation between these species in snout profile and squamosal shape, supporting their distinction. A new phylogenetic analysis of Anomodontia reveals that \u201cDicynodon\u201d is polyphyletic, necessitating taxonomic revision at the generic level. D. benjamini and D. limbus are basal cryptodonts, whereas the other valid \u201cDicynodon\u201d species are basal dicynodontoids. The genus Dicynodon is restricted to D. lacerticeps and D. huenei. We reinstate use of Daptocephalus, Sintocephalus, Turfanodon, Daqingshanodon, Jimusaria, and Gordonia for other species. We synonymize Vivaxosaurus permirus and Dicynodon trautscholdi (as V. trautscholdi, comb. nov.) We establish new generic names for several species formerly included in Dicynodon: Peramodon amalitzkii, comb. nov., Keyseria benjamini, comb. nov., Euptychognathus bathyrhynchus, comb. nov., Syops vanhoepeni, comb. nov., and Basilodon woodwardi, comb. nov. Of the main Karoo Permian taxa, Dicynodon, Basilodon, and Dinanomodon range throughout the Cistecephalus and Dicynodon assemblage zones, but Daptocephalus is restricted to the Dicynodon Assemblage Zone. An online version of this Memoir containing color versions of Figures 4 to 152 is available online on the publishers' website. Subscribers accessing the Memoir online may also download a high-resolution version of the pages, but due to its size please note that it is available in 4 parts in the \u201csupplemental files\u201d area. Supplemental data matrices and specimen lists are also available in the \u201csupplemental files\u201d area.", "keyphrases": ["taxonomic revision", "dicynodon", "anomodontia", "jimusaria"]}
{"id": "10.1080/02724634.2019.1599901", "title": "First Record of Sivameryx (Cetartiodactyla, Anthracotheriidae) from the Lower Miocene of Israel Highlights the Importance of the Levantine Corridor As a Dispersal Route Between Eurasia and Africa", "abstract": "ABSTRACT \n The genus Sivameryx (Cetartiodactyla: Anthracotheriidae), found in both Asia and Africa, is considered of Asian origin. Recent excavations in the Negev region of southern Israel led to the discovery of a new early Miocene site called Kamus Junction. Among the fossils recovered at Kamus Junction is an upper molar of Sivameryx palaeindicus. Although known species of Sivameryx have often been distinguished by size, comparisons of the new specimen with known Sivameryx teeth from Asia and Africa emphasize the need for caution when assigning Sivameryx fossils to species based on size alone. This record of Sivameryx highlights the importance of the Levant as a corridor connecting Eurasia and Africa. The new find, along with other recent finds, demonstrates that the Levantine Corridor facilitated faunal dispersal events that shaped modern biotas as early as the early Miocene.", "keyphrases": ["sivameryx", "cetartiodactyla", "anthracotheriidae"]}
{"id": "10.5194/cp-7-831-2011", "title": "Down the Rabbit Hole: toward appropriate discussion of methane release from gas hydrate systems during the Paleocene-Eocene thermal maximum and other past hyperthermal events", "abstract": "Abstract. Enormous amounts of 13C-depleted carbon rapidly entered the exogenic carbon cycle during the onset of the Paleocene-Eocene thermal maximum (PETM), as attested to by a prominent negative carbon isotope (\u03b413C) excursion and deep-sea carbonate dissolution. A widely cited explanation for this carbon input has been thermal dissociation of gas hydrate on continental slopes, followed by release of CH4 from the seafloor and its subsequent oxidation to CO2 in the ocean or atmosphere. Increasingly, papers have argued against this mechanism, but without fully considering existing ideas and available data. Moreover, other explanations have been presented as plausible alternatives, even though they conflict with geological observations, they raise major conceptual problems, or both. Methane release from gas hydrates remains a congruous explanation for the \u03b413C excursion across the PETM, although it requires an unconventional framework for global carbon and sulfur cycling, and it lacks proof. These issues are addressed here in the hope that they will prompt appropriate discussions regarding the extraordinary carbon injection at the start of the PETM and during other events in Earth's history.", "keyphrases": ["appropriate discussion", "methane release", "paleocene-eocene thermal maximum", "carbon"]}
{"id": "paleo.010650", "title": "Phylogenomic analysis of the bowfin (Amia calva) reveals unrecognized species diversity in a living fossil lineage", "abstract": "The Bowfin (Amia calva), as currently recognized, represents the sole living member of the family Amiidae, which dates back to approximately 150 Ma. Prior to 1896, 13 species of extant Bowfins had been described, but these were all placed into a single species with no rationale or analysis given. This situation has persisted until the present day, with little attention given to re-evaluation of those previously described nominal forms. Here, we present a phylogenomic analysis based on over 21,000 single nucleotide polymorphisms (SNPs) from 94 individuals that unambiguously demonstrates the presence of at least two independent evolutionary lineages within extant Amia populations that merit species-level standing, as well as the possibility of two more. These findings not only expand the recognizable species diversity in an iconic, ancient lineage, but also demonstrate the utility of such methods in addressing previously intractable questions of molecular systematics and phylogeography in slowly evolving groups of ancient fishes.", "keyphrases": ["bowfin", "amia calva", "phylogenomic analysis"]}
{"id": "paleo.011154", "title": "New Specimens of Yanornis Indicate a Piscivorous Diet and Modern Alimentary Canal", "abstract": "A crop adapted for an herbivorous diet of seeds has previously been documented in the Early Cretaceous birds Sapeornis and Hongshanornis. Here we report on several specimens of Yanornis that preserve a crop containing fish. One specimen preserves two whole fish in the oesophagus, indicating that Early Cretaceous birds shared trophic specializations with Neornithes for the increased energetic demands of flight \u2013 namely the storing of food for later consumption when the stomach is full. Whole fish also indicate that despite their presence, teeth were not used to orally process food, suggesting the hypertrophied dentition in this taxon were utilized in prey capture. The presence of macerated fish bones in the crop of other specimens indicates the highly efficient advanced muscular system of peristalsis responsible for moving ingested items between different segments of the alimentary canal was also in place. Despite the fact many features of the modern avian alimentary canal are inferred to compensate for the absence of teeth in birds (expandable oesophagus, grinding gizzard), the derived alimentary canal was apparently present in toothed Cretaceous birds. Although Yanornis was considered to have switched their diet from piscivorous to herbivorous, based on position and morphology we reinterpret the gastroliths reported in one specimen as sand impacted in the intestines, and reconstruct the taxon as primarily piscivorous. This is a novel interpretation for fossilized gastroliths, and the first documentation of this condition in the fossil record.", "keyphrases": ["yanornis", "crop", "peristalsis", "morphology"]}
{"id": "10.1127/nos/2018/0445", "title": "High-resolution bio- and chemostratigraphy of an expanded record of Oceanic Anoxic Event 2 (Late Cenomanian\u2013Early Turonian) at Clot Chevalier, near Barr\u00eame, SE France (Vocontian Basin)", "abstract": "A newly located exposure of the Niveau Thomel, an organic-\u00ad\u2010rich level at the Cenomanian\u2013Turonian boundary, provides a highly expanded record of Oceanic Anoxic Event (OAE) 2, excepted for the lower relatively condensed glauconite-\u00adrich part of the section. The new locality, close to Barreme in the Vocontian Basin, SE France, is developed in deep-\u00adwater hemi-\u00adpelagic facies (shales, marls, marly limestones, variably enriched in organic matter) and provides an improved understanding of palaeoceanographic events associated with OAE 2. Investigation of the biostratigraphy (nannofossils and planktonic foramininfera), organic and inorganic geochemistry (bulk carbonate \u03b418O, total organic carbon (TOC), bulk organic, biomarker-specific and carbonate \u03b413C, major and trace elements, and Rock-\u00adEval data) has allowed characterization of the sediments in great detail. The combined study further constrains the detailed relationship between bio-\u00ad and chemostratigraphy (particularly with respect to the details of the well-\u00addisplayed positive carbon-\u00ad\u2010isotope excursion) for this interval. The section also provides new evidence, in the form of a positive oxygen-\u00adisotope excursion and an offset between carbonate and organic-\u00adcarbon carbon-\u00adisotope records, which confirms the importance of cooling accompanied by a drop in dissolved CO2 in near-\u00adsurface waters during the Plenus Cold Event that characterized the early part of OAE 2. Evidence for increased oxygenation of bottom waters, together with elevated concentrations of redox-\u00adsensitive and chalcophilic elements registered elsewhere through the level of the Plenus Cold Event, may be reflected in enhanced concentrations of iron (in glauconite) and nickel in coeval strata from the Clot Chevalier section.", "keyphrases": ["chemostratigraphy", "oceanic anoxic event", "vocontian basin", "marly limestone", "organic carbon"]}
{"id": "10.1130/B30571.1", "title": "Life at the top of the greenhouse Eocene world--A review of the Eocene flora and vertebrate fauna from Canada's High Arctic", "abstract": "Early\u2013middle Eocene (ca. 53\u201338 Ma) sediments of the Eureka Sound Group in Canada\u2019s Arctic Archipelago preserve evidence of lush mixed conifer-broadleaf rain forests, inhabited at times by alligators, turtles, and diverse mammals, including primates, tapirs, brontotheres, and hippo-like Coryphodon. This biota reflects a greenhouse world, offering a climatic and ecologic deep time analog of a mild ice-free Arctic that may be our best means to predict what is in store for the future Arctic if current climate change goes unchecked. In our review of the early\u2013middle Eocene Arctic flora and vertebrate fauna, we place the Arctic fossil localities in historic, geographic, and stratigraphic context, and we provide an integrated synthesis and discussion of the paleobiology and paleoecology of these Eocene Arctic forests and their vertebrate inhabitants. The abundance and diversity of tapirs and plagiomenids (both rare elements in midlatitude faunas), and the absence of artiodactyls, early horses, and the hyopsodontid \u201ccondylarth\u201d Hyopsodus (well represented at midlatitude localities) are peculiar to the Eocene Arctic. The Eocene Arctic macrofloras reveal a forested landscape analogous to the swamp-cypress and broadleaf floodplain forests of the modern southeastern United States. Multiple climate proxies indicate a mild temperate early\u2013middle Eocene Arctic with winter temperatures at or just above freezing and summer temperatures of 20 \u00b0C (or higher), and high precipitation. At times, this high precipitation resulted in freshwater discharge into a nearly enclosed Arctic Ocean basin, sufficient to cause surface freshening of the Arctic Ocean, supporting mats of the floating fern Azolla . Fluctuating Arctic Ocean sea level due to freshwater inputs as well as tectonics produced temporary land bridges, allowing land plants and animals to disperse between North America and both Europe and Asia.", "keyphrases": ["eocene", "review", "arctic"]}
{"id": "10.1029/2019GL086046", "title": "Opportunities and Challenges for Paleoaltimetry in \u201cSmall\u201d Orogens: Insights From the European Alps", "abstract": "Many stable isotope paleoaltimetry studies have focused on paleoelevation reconstructions of orogenic plateaus such as the Tibetan or Andean Plateaus. We address the opportunities and challenges of applying stable isotope paleoaltimetry to \u201csmaller\u201d orogens. We do this using a high\u2010resolution isotope tracking general circulation model (ECHAM5\u2010wiso) and explore the precipitation \u03b418O (\u03b418Op) signal of Cenozoic paleoclimate and topographic change in the European Alps. Results predict a maximum \u03b418Op change of 4\u20135\u2030 (relative to present day) during topographic development of the Alps. This signal of topographic change has the same magnitude as changes in \u03b418Op values resulting from Pliocene and Last Glacial Maximum global climatic change. Despite the similar magnitude of the isotopic signals resulting from topographic and paleoclimate changes, their spatial patterns across central Europe differ. Our results suggest that an integration of paleoclimate modeling, multiproxy approaches, and low\u2010elevation reference proxy records distal from an orogen improve topographic reconstructions.", "keyphrases": ["european alps", "topographic change", "pliocene", "glacial maximum"]}
{"id": "paleo.004680", "title": "Environmental control on the biogeographical distribution of Desmanella (Soricomorpha, Mammalia) in the Miocene of the Iberian Peninsula", "abstract": "Abstract:\u2002 This paper reports the first record of Desmanella (Mammalia, Soricomorpha) from the Granada Basin in southern Iberian Peninsula, which represents its south\u2010westernmost occurrence in all Eurasia. It is a controversial taxon whose systematic assignment has been discussed for a long time. This genus belongs to the family Talpidae, a group of insectivores that include extant moles, shrew moles and desmans. Desmanella was very abundant in the late Miocene and early Pliocene of Eurasia, including several basins of northern Iberian Peninsula, but it has not been found until now in southern Iberia. Previous studies have shown that the faunal record and the climatic conditions during the Neogene in the Granada Basin were different from other areas of the Iberian Peninsula. The particular distribution of Desmanella supports the hypothesis that specific climatic features (wetter than neighbouring areas) prevailed in the Granada Basin during the late Turolian (late Miocene).", "keyphrases": ["mammalia", "miocene", "iberian peninsula"]}
{"id": "paleo.008888", "title": "Are the Rhizomyinae and the Spalacinae closely related? Contradistinctive conclusions between genetics and palaeontology", "abstract": "The reconstruction of the evolutionary history of the Rhizomyinae and the Spalacinae based on the fossil record strongly suggests that these do not share the same murid ancestor and developed separately since the early Oligocene. This conclusion is supported by the difference in evolutionary dynamics between these groups during the Miocene and Pliocene. Molecular genetic studies of extant representatives of the Rhizomyinae, Spalacinae and Myospalacinae, however, suggest that these subfamilies share similarities that distinguish them from all other Muridae. As a result, geneticists unite these subfamilies into the family Spalacidae and consider the Spalacidae and the Muridae to be sister lineages. Until the conflict between the two disciplines is resolved we prefer to maintain the Rhizomyinae and the Spalacinae as two subfamilies within the family Muridae (superfamily Muroidea).", "keyphrases": ["rhizomyinae", "spalacinae", "conclusion", "phylogenetic position"]}
{"id": "10.1128/microbiolspec.PoH-0006-2015", "title": "Paleopathology and Paleomicrobiology of Malaria.", "abstract": "Malaria is a disease caused by parasites of the genus Plasmodium, transmitted through the bites of female anopheles flies. Plasmodium falciparum causes severe malaria with undulating high fever (malaria tropica). Literary evidence of malarial infection dates back to the early Greek period, when Hippocrates described the typical undulating fever highly suggestive of plasmodial infection. Recent immunological and molecular analyses describe the unambiguous identification of malarial infections in several ancient Egyptian mummies and a few isolated cases in Roman and Renaissance Europe. Although the numbers of cases are low, there is evidence that the overall infection rates may have been relatively high and that this infectious disease may have had a significant impact on historical populations.", "keyphrases": ["malaria", "genus plasmodium", "infection", "typical undulating fever"]}
{"id": "paleo.012446", "title": "First Hominoid from the Late Miocene of the Irrawaddy Formation (Myanmar)", "abstract": "For over a century, a Neogene fossil mammal fauna has been known in the Irrawaddy Formation in central Myanmar. Unfortunately, the lack of accurately located fossiliferous sites and the absence of hominoid fossils have impeded paleontological studies. Here we describe the first hominoid found in Myanmar together with a Hipparion (s.l.) associated mammal fauna from Irrawaddy Formation deposits dated between 10.4 and 8.8 Ma by biochronology and magnetostratigraphy. This hominoid documents a new species of Khoratpithecus, increasing thereby the Miocene diversity of southern Asian hominoids. The composition of the associated fauna as well as stable isotope data on Hipparion (s.l.) indicate that it inhabited an evergreen forest in a C3-plant environment. Our results enlighten that late Miocene hominoids were more regionally diversified than other large mammals, pointing towards regionally-bounded evolution of the representatives of this group in Southeast Asia. The Irrawaddy Formation, with its extensive outcrops and long temporal range, has a great potential for improving our knowledge of hominoid evolution in Asia.", "keyphrases": ["late miocene", "myanmar", "first hominoid"]}
{"id": "paleo.000328", "title": "The Archean origin of oxygenic photosynthesis and extant cyanobacterial lineages", "abstract": "The record of the coevolution of oxygenic phototrophs and the environment is preserved in three forms: genomes of modern organisms, diverse geochemical signals of surface oxidation and diagnostic Proterozoic microfossils. When calibrated by fossils, genomic data form the basis of molecular clock analyses. However, different interpretations of the geochemical record, fossil calibrations and evolutionary models produce a wide range of age estimates that are often conflicting. Here, we show that multiple interpretations of the cyanobacterial fossil record are consistent with an Archean origin of crown-group Cyanobacteria. We further show that incorporating relative dating information from horizontal gene transfers greatly improves the precision of these age estimates, by both providing a novel empirical criterion for selecting evolutionary models, and increasing the stringency of sampling of posterior age estimates. Independent of any geochemical evidence or hypotheses, these results support oxygenic photosynthesis evolving at least several hundred million years before the Great Oxygenation Event (GOE), a rapid diversification of major cyanobacterial lineages around the time of the GOE, and a post-Cryogenian origin of extant marine picocyanobacterial diversity.", "keyphrases": ["archean origin", "photosynthesis", "cyanobacterial lineage", "molecular clock analysis"]}
{"id": "10.1111/gcb.13214", "title": "Synchronous genetic turnovers across Western Eurasia in Late Pleistocene collared lemmings", "abstract": "Recent palaeogenetic studies indicate a highly dynamic history in collared lemmings (Dicrostonyx spp.), with several demographical changes linked to climatic fluctuations that took place during the last glaciation. At the western range margin of D. torquatus, these changes were characterized by a series of local extinctions and recolonizations. However, it is unclear whether this pattern represents a local phenomenon, possibly driven by ecological edge effects, or a global phenomenon that took place across large geographical scales. To address this, we explored the palaeogenetic history of the collared lemming using a next\u2010generation sequencing approach for pooled mitochondrial DNA amplicons. Sequences were obtained from over 300 fossil remains sampled across Eurasia and two sites in North America. We identified five mitochondrial lineages of D. torquatus that succeeded each other through time across Europe and western Russia, indicating a history of repeated population extinctions and recolonizations, most likely from eastern Russia, during the last 50 000 years. The observation of repeated extinctions across such a vast geographical range indicates large\u2010scale changes in the steppe\u2010tundra environment in western Eurasia during the last glaciation. All Holocene samples, from across the species' entire range, belonged to only one of the five mitochondrial lineages. Thus, extant D. torquatus populations only harbour a small fraction of the total genetic diversity that existed across different stages of the Late Pleistocene. In North American samples, haplotypes belonging to both D. groenlandicus and D. richardsoni were recovered from a Late Pleistocene site in south\u2010western Canada. This suggests that D. groenlandicus had a more southern and D. richardsoni a more northern glacial distribution than previously thought. This study provides significant insights into the population dynamics of a small mammal at a large geographical scale and reveals a rather complex demographical history, which could have had bottom\u2010up effects in the Late Pleistocene steppe\u2010tundra ecosystem.", "keyphrases": ["western eurasia", "late pleistocene", "lemming"]}
{"id": "10.1139/z90-297", "title": "Classification of Tertiary fossil Donaciinae of North America and their implications about evolution of Donaciinae (Coleoptera: Chrysomelidae)", "abstract": "Specimens of Donacia primaeva Wickham from the Oligocene Florissant shales of Colorado are indistinguishable from male specimens of the extant species Plateumaris nitida (Germar), and are assigned to the P. nitida group. A fossil from the Late Paleocene Paskapoo Formation of Alberta (Donacia wightoni n.sp.) is the oldest fossil of Donaciinae, assigned to Donacia (Donacia), an ecologically and structurally highly derived subgenus. Both species are assigned to small groups of extant species which are not the most primitive Donaciinae. They are similar to extant taxa, which suggests they have maintained considerable structural stasis over a long period of time.", "keyphrases": ["donaciinae", "coleoptera", "chrysomelidae"]}
{"id": "10.1371/journal.pone.0052625", "title": "A New Genus of Aplodontid Rodent (Mammalia, Rodentia) from the Late Oligocene of Northern Junggar Basin, China", "abstract": "A new genus and species of aplodontid rodent, Proansomys dureensis, from the late Oligocene of the northern Junggar Basin of China is described. The new genus is referred to as Ansomyinae because the ectoloph on the upper cheek teeth, although not fully crested, has attained the same characteristic bucket-handle-shaped configuration as other members of the subfamily. It represents the earliest record of the subfamily yet discovered in Asia and is more plesiomorphic than species of the genus Ansomys in having a partly crested ectoloph, a lower degree of lophodonty, and less complex tooth basins (lacking accessory lophules). Proansomys has transitional features between Prosciurus and Ansomys, suggesting that the Ansomyinae derived from a group of aplodontids related to Prosciurus, as did other advanced aplodontid rodents. This provides new light on the paleobiogeography of the Ansomyinae.", "keyphrases": ["new genus", "aplodontid rodent", "late oligocene"]}
{"id": "10.1029/97pa00318", "title": "Strontium/calcium ratios in modern porites corals From the Great Barrier Reef as a proxy for sea surface temperature: Calibration of the thermometer and monitoring of ENSO", "abstract": "High-precision Sr/Ca ratios are reported for Porites corals from Davies Reef, at \u223c19\u00b0S on the midshelf of the Great Barrier Reef, Australia. Skeletal growth parameters were also determined from coral slabs using X ray photographs and \u03b3-densitometry measurements. A calibration of the Sr/Ca thermometer has been obtained, using in situ measured sea surface temperatures, which gives Sr/Ca \u00d7 10\u00b3 = 10.48 (\u00b10.01) \u2212 0.0615 (\u00b10.0004) \u00d7 T, whereT is in \u00b0C. This calibration applies to different species of Porites and a large range of annual extension and calcification rates, provided sampling follows a major growth axis. Biases of 1\u00b0\u20132\u00b0C have been observed in the low-density margins where growth is hampered by interfering fans of corallites. The analytical and the long-term reproducibility of Sr/Ca-derived temperatures are both better than \u00b10.3\u00b0C (2\u03c3). Coral growth parameters such as the extension rate or density generally appear to respond to environmental changes such as rainfall but do not affect the Sr/Ca partitioning between coralline aragonite and seawater. No correlation has been found between calcification rate and Sr/Ca variations, consistent with Sr/Ca being mainly controlled by temperature. In the Great Barrier Reef, the interannual variability in SST is primarily related to the El Nino-Southern Oscillation phenomenon and is typically marked by a cold anomaly during the winter preceding the mature warm phase. Instrumental records show that the surface waters of the Coral Sea around 19\u00b0S have experienced a significant cooling associated with the El Ninos of 1965, 1972, and 1982-1983 which the Porites corals record faithfully. The coral-derived temperatures for the period from 1965 to 1993 show an increase of 1.3\u00b0C, which has occurred mainly since 1979. This warming is larger in magnitude but consistent with the trend for the southern hemisphere land and marine temperature records, which shows an increase of around 0.4\u00b0C.", "keyphrases": ["great barrier reef", "sea surface temperature", "calibration"]}
{"id": "10.18563/journal.m3.99", "title": "3D model related to the publication: The endocranial anatomy of the stem turtle Naomichelys speciosa from the Early Cretaceous of North America", "abstract": "The present 3D Dataset contains the 3D model analyzed in the following publication: Paulina-Carabajal, A., Sterli, J., Werneburg, I., 2019. The endocranial anatomy of the stem turtle Naomichelys speciosa from the Early Cretaceous of North America. Acta Palaeontologica Polonica, https://doi.org/10.4202/app.00606.2019", "keyphrases": ["publication", "endocranial anatomy", "early cretaceous"]}
{"id": "10.1006/jhev.1998.0219", "title": "Late Pleistocene human population bottlenecks, volcanic winter, and differentiation of modern humans.", "abstract": "The \"Weak Garden of Eden\" model for the origin and dispersal of modern humans (Harpending et al., 1993) posits that modern humans spread into separate regions from a restricted source, around 100 ka (thousand years ago), then passed through population bottlenecks. Around 50 ka, dramatic growth occurred within dispersed populations that were genetically isolated from each other. Population growth began earliest in Africa and later in Eurasia and is hypothesized to have been caused by the invention and spread of a more efficient Later Stone Age/Upper Paleolithic technology, which developed in equatorial Africa. Climatic and geological evidence suggest an alternative hypothesis for Late Pleistocene population bottlenecks and releases. The last glacial period was preceded by one thousand years of the coldest temperatures of the Later Pleistocene (approximately 71-70 ka), apparently caused by the eruption of Toba, Sumatra. Toba was the largest known explosive eruption of the Quaternary. Toba's volcanic winter could have decimated most modern human populations, especially outside of isolated tropical refugia. Release from the bottleneck could have occurred either at the end of this hypercold phase, or 10,000 years later, at the transition from cold oxygen isotope stage 4 to warmer stage 3. The largest populations surviving through the bottleneck should have been found in the largest tropical refugia, and thus in equatorial Africa. High genetic diversity in modern Africans may thus reflect a less severe bottleneck rather than earlier population growth. Volcanic winter may have reduced populations to levels low enough for founder effects, genetic drift and local adaptations to produce rapid population differentiation. If Toba caused the bottlenecks, then modern human races may have differentiated abruptly, only 70 thousand years ago.", "keyphrases": ["population bottleneck", "volcanic winter", "modern human", "africa"]}
{"id": "paleo.002169", "title": "The early Turolian (late Miocene) Cervidae (Artiodactyla, Mammalia) from the fossil site of Dorn-D\u00fcrkheim 1 (Germany) and implications on the origin of crown cervids", "abstract": "Dental and cranial appendage remains of Cervidae from the fossil site of Dorn-D\u00fcrkheim are studied in detail. The material mainly includes isolated teeth, isolated pedicles and antler pieces. Neither tooth rows nor complete appendages are recorded. Comparative morphology and statistics of morphometrics (principal component analysis and discriminant analysis) allow for the classification of small and large dentitions, small cranial appendages, two morphotypes of large pedicles and two morphotypes of large antlers.\nPossible combinations of the classified units document the sympatric occurrence of three species, namely, Procapreolus sp., Muntiacinae gen. and sp. indet., cf. Cervavitulus mimus, but the fragmentary condition of the material leads to ambiguity regarding their composition and, consequently, to a certain extent regarding the taxonomic identification. However, these remains indicate the contemporaneous occurrence of early Turolian members of the crown cervids Muntiacinae and Capreolinae and close a previous spatiotemporal gap in the European cervid record. In addition, their presence proves the progressive turnover from dichotomous-antlered muntiacines to early monopodialantlered crown cervids from NE to SW Europe in the late Miocene. The taxonomical assignment challenges the recent hypothesis on the origin of crown Cervidae around the middle/late Miocene border since Dorn-D\u00fcrkheim cervids provide further evidence for the successive achievement of derived characters in cranial appendages of crown cervids (mediopostorbital position and backwards orientation of pedicles, coronet development, shaft development/elongation, beam development and increase in number of antler tines) in the lineage of crown cervids, which originated during the middle Miocene.", "keyphrases": ["cervidae", "fossil site", "crown cervid"]}
{"id": "paleo.009306", "title": "Megalictis, the Bone-Crushing Giant Mustelid (Carnivora, Mustelidae, Oligobuninae) from the Early Miocene of North America", "abstract": "We describe cranial and mandibular remains of three undescribed individuals of the giant mustelid Megalictis ferox Matthew, 1907 from the latest Arikareean (Ar4), Early Miocene mammal fauna of Nebraska, and Wyoming (USA) housed at the American Museum of Natural History (New York, USA). Our phylogenetic hypothesis indicates that Ar4 specimens assigned to M. ferox constitute a monophyletic group. We assign three additional species previously referred to Paroligobunis to Megalictis: M. simplicidens, M. frazieri, and \u201cM.\u201d petersoni. The node containing these four species of Megalictis and Oligobunis forms the Oligobuninae. We test the hypothesis that Oligobuninae (Megalictis and Oligobunis) is a stem mustelid taxon. Our results indicate that the Oligobuninae form the sister clade to the crown extant mustelids. Based on the cranium, M. ferox is a jaguar-size mustelid and the largest terrestrial mustelid known to have existed. This new material also sheds light on a new ecomorphological interpretation of M. ferox as a bone-crushing durophage (similar to hyenas), rather than a cat-like hypercarnivore, as had been previously described. The relative large size of M. ferox, together with a stout rostrum and mandible made it one of the more powerful predators of the Early Miocene of the Great Plains of North America.", "keyphrases": ["oligobuninae", "early miocene", "megalictis"]}
{"id": "paleo.008108", "title": "Soft-tissue anatomy of the Plesiosaur pectoral girdle inferred from basal Eosauropterygia taxa and the extant phylogenetic bracket", "abstract": "Plesiosaurians are highly derived secondarily-adapted organisms (if fishes are primarily-adapted) with a long evolutionary history, and they are closely related with basal eosauropterygians. Attempts to reconstruct soft-tissue anatomy can be complicated due to the lack of extant closely-related species, thus various lines of evidence must be considered. This study aims to reconstruct the pectoral girdle myology of eosauropterygians. Information derived from the extant phylogenetic bracket method was not sufficient to clarify muscle attachments in the pectoral girdle of plesiosaurians. To correctly infer muscle homologies, the extant phylogenetic bracket information had to be complemented with developmental and osteological information, and osteological transformations had to be traced back to Permian basal neodiapsids. The reconstructed pectoral girdle musculature presented here is, thus, significantly different from previous attempts. As in secondarily-adapted aquatic modern analogues, several muscles atrophied (e.g., pectoralis, episternocleidomastoideus) and others specialized (e.g., coracobrachialis, clavodeltoideus) in order to attain a more influential role to the stringent conditions of subaquatic locomotion. The subcoracoscapularis, scapulodeltoideus, scapulohumeralis and supracoracoideus are inferred to be glenohumeral stabilizers. The clavodeltoideus acted as the main protractor muscle and the coracobrachialis as a major retractor muscle, possibly in conjunction with the latissimus dorsi. Several heads of the triceps possibly atrophied, as in whales, serving mainly as a cubital joint stabilizer. The trapezius, serratus and levator scapulae served as pectoral girdle stabilizers.", "keyphrases": ["pectoral girdle", "plesiosaurian", "soft-tissue anatomy"]}
{"id": "10.3390/geosciences9120514", "title": "The Fossil Record of Darkling Beetles (Insecta: Coleoptera: Tenebrionidae)", "abstract": "The fossil record of Tenebrionidae (excluding the Quartenary) is presented. In total, 122 fossil species, clearly belonging to the family, are known; some beetles were determined only to genus; 78 genera are listed in the fossil record, including 29 extinct genera. The great diversity of tenebrionids occurs in the Lower Cretaceous Lagerst\u00e4tte of China (Yixian Formation), Middle Paleocene of France (Menat), Lower Eocene deposits of Germany (Geiseltal), Upper Eocene Baltic amber (Eastern Europe), Upper Eocene deposits of Florissant Formation (USA) and Miocene (Dominican amber). Tenebrionids of the following major lineages, including seven subfamilies, are currently known in the fossil record. These include the lagrioid branch (Lagriinae, Nilioninae), pimelioid branch (Pimeliinae), and tenebrioid branch (Alleculinae, Tenebrioninae, Diaperinae, Stenochiinae). The importance of the fossil record for evolutionary reconstructions and phylogenetic patterns is discussed. The oldest Jurassic and Early Cretaceous darkling beetles of the tenebrionoid branch consist of humid-adapted groups from the extant tribes Alleculini, Ctenopodiini (Alleculinae), and Alphitobiini (Tenebrioninae). Thus, paleontological evidence suggests that differentiation of the family started at least by the Middle Jurassic but does not indicate that xerophilic darkling beetles differentiated much earlier than mesophilic groups.", "keyphrases": ["beetle", "tenebrionidae", "fossil specie", "jurassic", "cenozoic amber"]}
{"id": "paleo.010862", "title": "Osteology of the first skull of Aetosauroides scagliai Casamiquela 1960 (Archosauria: Aetosauria) from the Upper Triassic of southern Brazil (Hyperodapedon Assemblage Zone) and its phylogenetic importance", "abstract": "Aetosauria, which includes 30 species, is a diverse group of armored pseudosuchian archosaurs restricted to Upper Triassic beds. Three species occur in Brazil, and one of these, Aetosauroides scagliai Casamiquela, 1960, also occurs in Argentina. The specimen UFSM 11505, found at Faixa Nova\u2013Cerrito I Outcrop, Santa Maria Formation (Hyperodapedon Assemblage Zone), Santa Maria, Rio Grande do Sul State, Brazil, is here referred to as Aetosauroides scagliai. This specimen preserves most of the skull with both hemimandibles in association with most of the postcranium, thus representing one of the most complete aetosaur skeletons found in Brazil. The premaxilla, one of the key elements of the cranial morphology of aetosaurs, along with the posterior portion of the mandible, was not described until now for A. scagliai. In contrast to the typothoracinae aetosaurs, the premaxilla of UFSM 11505 presents a shovel-shaped tip, but it is not as prominent as the lateral expansion of desmatosuchian aetosaurs, including both species of Stagonolepis, S. robertsoni Agassiz, 1844 and S. olenkae Sulej, 2010. The retroarticular process of the mandible is elongate and not tall, as in Stenomity huangae Small & Martz, 2013 and other typothoracinae aetosaurs. Unlike previous descriptions of A. scagliai, the maxillary teeth are recurved ziphodont-like with serrations on the entire length of both margins. Premaxillary teeth are also present, being less recurved than the maxillary teeth and cylindrical. We recovered Aetosauroides scagliai as the most basal taxon within Aetosauria, like previous phylogenetic analyses. Furthermore, our analyses reinforce that recurved and unconstricted maxillary teeth, the shovel-shaped premaxilla and the presence of a tuber on the surangular are plesiomorphic features of Aetosauria.", "keyphrases": ["skull", "aetosauroides scagliai casamiquela", "aetosauria"]}
{"id": "10.1890/06-0644.1", "title": "SEDIMENTS TELL THE HISTORY OF EUTROPHICATION AND HYPOXIA IN THE NORTHERN GULF OF MEXICO", "abstract": "We examined a suite of paleoindicators in 210Pb-dated sediment cores to determine the historical course of primary production, eutrophication, and oxygen stress in the coastal ocean adjacent to the plumes of the Mississippi and Atchafalaya rivers. The assumption that hypoxia is a natural feature of the coastal ecosystem in the northern Gulf of Mexico influenced by the discharge of the Mississippi River system is not supported by paleoindicators in accumulated sediments. There is a propensity for the ecosystem to develop hypoxia because of the high discharge of the Mississippi River and physical dynamics on the continental shelf that support stratification. However, paleoindicators of eutrophication and oxygen conditions record recent anthropogenic influences. The evidence for increased carbon production and accumulation comes from diatoms and their remnants, marine-origin carbon in the sediments, and phytoplankton pigments. Surrogates for oxygen condition, including mineral, isotopic, microfossil, and phytoplankton pigment indicators, indicate worsening oxygen stress. The changes are more apparent in areas of present chronic hypoxia and are coincident with the increasing nitrogen loads from the Mississippi River system beginning in the 1950s. Longer-term shifts in offshore ecology parallel landscape changes within the watershed in the last two centuries. The temporal shifts in this coastal ecosystem parallel the time sequence of similarly eutrophied coastal waters globally and coincide nicely with sediment analyses from other locations.", "keyphrases": ["eutrophication", "hypoxia", "northern gulf", "watershed"]}
{"id": "paleo.010946", "title": "Extreme warmth and heat-stressed plankton in the tropics during the Paleocene-Eocene Thermal Maximum", "abstract": "During rapid global warming 56 million years ago, tropical sea surface temperatures exceeded 36\u00b0C and stressed eukaryotic plankton. Global ocean temperatures rapidly warmed by ~5\u00b0C during the Paleocene-Eocene Thermal Maximum (PETM; ~56 million years ago). Extratropical sea surface temperatures (SSTs) met or exceeded modern subtropical values. With these warm extratropical temperatures, climate models predict tropical SSTs >35\u00b0C\u2014near upper physiological temperature limits for many organisms. However, few data are available to test these projected extreme tropical temperatures or their potential lethality. We identify the PETM in a shallow marine sedimentary section deposited in Nigeria. On the basis of planktonic foraminiferal Mg/Ca and oxygen isotope ratios and the molecular proxy TEX86H, latest Paleocene equatorial SSTs were ~33\u00b0C, and TEX86H indicates that SSTs rose to >36\u00b0C during the PETM. This confirms model predictions on the magnitude of polar amplification and refutes the tropical thermostat theory. We attribute a massive drop in dinoflagellate abundance and diversity at peak warmth to thermal stress, showing that the base of tropical food webs is vulnerable to rapid warming.", "keyphrases": ["warmth", "plankton", "paleocene-eocene thermal maximum"]}
{"id": "paleo.005386", "title": "Competition between encrusters on marine hard substrates and its fossil record", "abstract": "Many animals and plants that colonize hard surfaces in the sea are sessile and either bore into, or cement themselves permanently to the substrate surface. Because they retain their life positions after fossilization, these sclerobionts offer scope for studying biotic interactions in the fossil record. Encrusting sclerobionts compete actively for living space, with dominant competitors overgrowing the edges of subordinates. In addition to such marginal overgrowths, spatial competition may also occur through fouling in which larvae recruit directly onto the living surfaces of established sclerobionts. Spatial competition has been studied extensively in modern marine communities but there has been little research on competition between encrusters in ancient communities. This reflects poor knowledge of the taxonomy of the sclerobionts involved, as well as problems in distinguishing between overgrowth in vivo and post\u2010mortem. Nevertheless, if carefully interpreted, the fossil record of sclerobionts can provide an as yet largely unexploited resource for studying the long\u2010term ecological and evolutionary dynamics of competition.", "keyphrases": ["hard substrate", "biotic interaction", "fouling", "competition", "bryozoan"]}
{"id": "10.1017/s0094837300012215", "title": "Taphonomic bias and the evolutionary history of the family Cidaridae (Echinodermata: Echinoidea)", "abstract": "The class Echinoidea apparently originated during the Ordovician Period and diversified slowly through the Paleozoic Era. The clade then mushroomed in diversity beginning in Late Triassic time and continued expanding into the present. Although this evolutionary history is generally accepted, the taphonomic overprint affecting it has not been explored. To gain a more accurate perception of the evolutionary history of the group, I have compared the diversity history of the family Cidaridae (Echinodermata: Echinoidea) with the preservational style of fossil type species using literature-derived data. The Cidaridae apparently originated in Middle Triassic time and diversified slowly through the Neocomian (Early Cretaceous). Diversity was maintained through the remainder of the Cretaceous and Tertiary Periods, reflecting the diversity history of the subclass. Characterization of the preservational style of type fossil material for the family revealed the following breakdown of preservational states: 60% of species were described on the basis of disarticulated skeletal material, primarily spines; 20% based on intact coronas denuded of spines, apical system, Aristotle's lantern and peristomial plates; 10% based on large coronal fragments; and 10% based on other skeletal elements. This distribution may represent the effect of a disarticulation threshold on the condition of echinoid carcasses before final burial and suggests that preservation of intact specimens may be very unlikely. For cidaroids, previous work has suggested that this threshold is likely to be reached after 7 days of decay. Comparison of the diversity history of the Cidaridae with the preservation data reveals that characteristic patterns of taphonomic overprint have affected the group since its origination in Middle Triassic time, and the nature of that overprint has changed over time: the early diversity history of the group is characterized by occurrences of fragmented fossil material, with spines predominant; further radiation of the group in mid-Jurassic time coincided with an increase in modes of preservation, ranging between exceptionally well-preserved material and disarticulated skeletal elements. Finally, type material is more rarely described from younger stratigraphic intervals (Miocene\u2013Pleistocene) and consists predominantly of disarticulated skeletal elements and coronal fragments larger than an interambulacrum in size. Intact, denuded coronas are noticeably lacking. The number of type species of Cidaridae described in each stratigraphic interval has not been consistent during post-Paleozoic time. Middle Triassic, Malm (Upper Jurassic), Senonian (Upper Cretaceous) and Eocene series yielded significantly (\u03b1 = .05) higher numbers of type specimens per million years, while the Lias (Lower Jurassic), Dogger (Mid-Jurassic), Lower Cretaceous and Paleocene yielded significantly (\u03b1 = .05) lower numbers of type specimens per million years. This may be the result of a combination of taxonomic, sampling, and geographical biases.", "keyphrases": ["evolutionary history", "echinodermata", "echinoidea", "fragment"]}
{"id": "paleo.000138", "title": "New specimens of the earliest European passeriform bird", "abstract": "We describe new specimens of the oldest European passeriform bird from the early Oligocene of Germany. This bird has hitherto been known only from a poorly preserved skeleton and we report here a second slab of the same specimen and an additional fragmentary skull. The new specimens allow the description of a new species, Wieslochia weissi gen. et. sp. nov., which lacks apomorphies of crown group Oscines, the taxon including most extant and all European passeriform species. In overall osteology, Wieslochia most closely resembles extant Suboscines but these similarities may be plesiomorphic for Passeriformes. W. weissi differs from the stem species pattern hypothesized for Eupasseres in the morphology of the distal carpometacarpus, the absence of a hooked processus acrocoracoideus (coracoid), and the presence of furrows instead of certain canals on the hypotarsus, and may even be outside crown group Eupasseres, the clade including Oscines and Suboscines. Because the earliest European fossil record of oscine passerines is from the late Oligocene, passerines outside crown group Oscines may have colonized Europe before the arrival of Oscines from the Australian continental plate.", "keyphrases": ["european passeriform bird", "passeriformes", "new specimen"]}
{"id": "10.11646/zootaxa.4243.2.2", "title": "Exceptionally preserved Leptolepidae (Actinopterygii, Teleostei) from the late Early Jurassic Fossil-Lagerst\u00e4tten of Grimmen and Dobbertin\u00a0(Mecklenburg-Western Pomerania, Germany).", "abstract": "Exceptionally well-preserved fishes of the family Leptolepidae (Actinopterygii, Teleostei) from the late Early Jurassic Fossil-Lagerst\u00e4tten of Grimmen and Dobbertin (Mecklenburg-Western Pomerania, NE Germany) are reported and detailed anatomical descriptions are given. The described material specifically derives from the \"Green Series\", which represents a specific facies that falls within the lower part of the early Toarcian Harpoceras falciferum ammonite Zone. Complete skeletons are rare, and most specimens are represented by isolated skulls. Most of the skulls are fully articulated and show only a low degree of compaction, while some specimens are almost three-dimensionally preserved. The leptolepid fauna comprises Leptolepis coryphaenoides, L. normandica, L. jaegeri, a possible Proleptolepis, and two other taxa, which are described in open nomenclature. Several anatomical characters, such as the shape of premaxilla, maxilla, dentary, preopercle, the cephalic sensory canals, and the dentition of the jaws, are discussed and compared to former studies. The new material provides novel insights into morphology, diversity and palaeobiogeography of leptolepid fishes. The records of Leptolepis coryphaenoides, L. normandica and L. jaegeri from Grimmen and Dobbertin represent the northeastern-most occurrences of these species from Europe, suggesting that they inhabited the whole central European epicontinental sea during the early Toarcian. The possible occurrence of Proleptolepis in the lower Toarcian of Grimmen suggests that this genus might have had a much wider palaeobiogeographical and temporal distribution, since specimens attributed to Proleptolepis have previously been reported only from the Sinemurian of western Europe.", "keyphrases": ["actinopterygii", "teleostei", "mecklenburg-western pomerania"]}
{"id": "paleo.007682", "title": "COMPUTED TOMOGRAPHY OF AN ANOLIS LIZARD IN DOMINICAN AMBER: SYSTEMATIC, TAPHONOMIC, BIOGEOGRAPHIC, AND EVOLUTIONARY IMPLICATIONS", "abstract": "The cranial morphology of an Anolis lizard preserved in Dominican amber, observed using pseudo-three-dimensional reconstructed images derived from highresolution X-ray computed tomography (CT) data, demonstrates the lack of a splenial in the lower jaw. The specimen is referred to T-clade anoles, the clade that includes the A. chlorocyanus species group, to which two other Dominican anoles in amber have been referred. The pattern of bone breakage and loss suggests trauma followed by decomposition prior to entombment. The trunk-crown ecomorph of A. chlorocyanus species group anoles was established on what was to become Hispaniola between approximately 33 and 20 million years ago.", "keyphrases": ["tomography", "anolis lizard", "dominican amber"]}
{"id": "paleo.000506", "title": "Endemicity and palaeobiogeography of the Osteostraci and Galeaspida: a test of scenarios of gnathostome evolution", "abstract": "Abstract:\u2002 Armoured stem\u2010gnathostomes (jawless vertebrates previously termed \u2018ostracoderms\u2019) have long been assumed to exhibit strong endemicity. This assumption has underpinned their utility in many palaeobiogeographic studies as well as scenarios regarding the evolution and dominance of jawed vertebrates over their jawless relatives. The hypothesis of endemicity in stem\u2010gnathostomes is investigated for the first time in the light of the phylogeny of the closest relatives of jawed vertebrates \u2013 Osteostraci and Galeaspida. Palaeobiogeography of each is reconstructed using Fitch optimization and modified Brooks Parsimony Analysis. Palaeobiogeographic distributions corroborate phylogeny. Results, along with consideration of the Heterostraci, enable identification of similar patterns across groups (broad ancestral range, Early Devonian expansion, endemic and pandemic clades within each, and Middle Devonian radiation events) and inferences to the palaeogeographic relationship between major terranes (i.e. Laurentia, Baltica, Avalonia, Kara, Altaids, South China, Tarim). Comparison of basin and terrane level analyses identifies the different palaeogeographic processes responsible for the distributions of each group: sea\u2010level changes in the case of the Osteostraci and rifting in the case of the Galeaspida. The general endemic nature of the Osteostraci and Galeaspida is confirmed, and thus the hypothesis that the demise and extinction of stem\u2010gnathostomes was because of their limited dispersal capacity is supported.", "keyphrases": ["palaeobiogeography", "galeaspida", "baltica", "endemicity"]}
{"id": "10.1080/02724634.1991.10011416", "title": "New early Barstovian (middle Miocene) vertebrates from the upper Torreya Formation, eastern Florida panhandle", "abstract": "ABSTRACT A new vertebrate fauna has been recovered from the Dogtown Member of the Torreya Formation, Hawthorn Group (early to middle Miocene), northern Gadsden County, Florida. Fossils were recovered from four fuller's earth clay mines. This new fauna, called the Willacoochee Creek Fauna (WCF), contains at least 68 vertebrate taxa, including 29 mammals, from marine, freshwater, and terrestrial environments. The WCF is restricted to the early Barstovian land-mammal age based on the presence of Copemys, Perognathus, Rakomeryx, and Ticholeptus, and the overlapping chronologic ranges of 8 other mammals. Lanthanotherium, Perognathus, and a squalodont whale are reported from the southeastern U.S. for the first time. Biochronological range extensions into the early Barstovian are proposed for Lanthanotherium, Anchitherium clarencei and \u201cMerychippus\u201d primus. The WCF is the first well documented early Barstovian fauna in the southeastern U.S., thus filling a large gap in the temporal distribution of vertebrate fau...", "keyphrases": ["early barstovian", "middle miocene", "torreya formation"]}
{"id": "paleo.003592", "title": "Shell microstructure of the early bivalve Pojetaia and the independent origin of nacre within the mollusca", "abstract": "Abstract:\u2002 Pojetaia and Fordilla are the oldest bivalve molluscs, occurring in roughly co\u2010eval rocks from the Tommotian, and are the only undisputed, well\u2010known bivalves from the Cambrian. New specimens reveal that Pojetaia had a laminar inner shell microstructure reminiscent of the foliated aragonite of modern monoplacophorans, and the same is true for Fordilla. A similar shell microstructure is seen in Anabarella and Watsonella, providing support for the hypothesis that they are the ancestors of bivalves. Foliated aragonite shares many similarities with nacre, and it may have been the precursor to nacre in bivalves. No cases of undisputed nacre occur in the Cambrian, in spite of much shell microstructure data from molluscs of this time period. Thus, although considered by many to be homologous among molluscs, we conclude that nacre convergently evolved in monoplacophorans, gastropods, bivalves, and cephalopods. This independent origin of nacre appears to have taken place during, or just prior to, the Great Ordovician Biodiversification Event and represents a significant step in the arms race between predators and molluscan prey.", "keyphrases": ["independent origin", "nacre", "shell microstructure"]}
{"id": "10.4202/app.00870.2020", "title": "The endemic radiodonts of the Cambrian Stage 4 Guanshan biota of South China", "abstract": "The Guanshan Biota (South China, Cambrian, Stage 4) contains a diverse assemblage of biomineralizing and non-biomineralizing animals. Sitting temporally between the Stage 3 Chengjiang and Wuliuan Kaili Biotas, the Guanshan Biota contains numerous fossil organisms that are exclusive to this exceptional deposit. The Guanshan Konservat-Lagerst\u00e4tte is also unusual amongst Cambrian strata that preserve non-biomineralized material, as it was deposited in a relatively shallow water setting. In this contribution we double the diversity of radiodonts known from the Guanshan Biota from two to four, and describe the second species of Paranomalocaris . In addition, we report the first tamisiocaridid from South China, and confirm the presence of a tetraradial oral cone bearing small and large plates in \u201cAnomalocaris\u201d kunmingensis , the most abundant radiodont from the deposit. All four radiodont species, and three genera, are apparently endemic to the Guanshan Biota. When considered in the wider context of geographically and temporally comparable radiodont faunas, endemism in Guanshan radiodonts is most likely a consequence of the shallower and more proximal environment in which they lived. The strong coupling of free-swimming radiodonts and benthic communities underlines the complex relationship between the palaeobiogeographic and environmental distributions of prey and predators. This local adaptation of radiodonts to their prey is highlighted by the frontal appendage morphology of the two species of Paranomalocaris , apparently specialised to different feeding modes, while the recognition of the limited geographic range of some radiodont faunas highlights the importance of exploring as many deposits as possible to fully understand this group.", "keyphrases": ["cambrian stage", "guanshan biota", "south china"]}
{"id": "10.1371/journal.pone.0044762", "title": "A Remarkable New Family of Jurassic Insects (Neuroptera) with Primitive Wing Venation and Its Phylogenetic Position in Neuropterida", "abstract": "Background Lacewings (insect order Neuroptera), known in the fossil record since the Early Permian, were most diverse in the Mesozoic. A dramatic variety of forms ranged in that time from large butterfly-like Kalligrammatidae to minute two-winged Dipteromantispidae. Principal Findings We describe the intriguing new neuropteran family Parakseneuridae fam. nov. with three new genera and 15 new species from the Middle Jurassic of Daohugou (Inner Mongolia, China) and the Early/Middle Jurassic of Sai-Sagul (Kyrgyzstan): Parakseneura undula gen. et sp. nov., P. albomacula gen. et sp. nov., P. curvivenis gen. et sp. nov., P. nigromacula gen. et sp. nov., P. nigrolinea gen. et sp. nov., P. albadelta gen. et sp. nov., P. cavomaculata gen. et sp. nov., P. inflata gen. et sp. nov., P. metallica gen. et sp. nov., P. emarginata gen. et sp. nov., P. directa gen. et sp. nov., Pseudorapisma jurassicum gen. et sp. nov., P. angustipenne gen. et sp. nov., P. maculatum gen. et sp. nov. (Daohugou); Shuraboneura ovata gen. et sp. nov. (Sai-Sagul). The family comprises large neuropterans with most primitive wing venation in the order indicated by the presence of ScA and AA1+2, and the dichotomous branching of MP, CuA, CuP, AA3+4, AP1+2. The phylogenetic position of Parakseneuridae was investigated using a phylogenetic analysis of morphological scoring for 33 families of extinct and extant Neuropterida combined with DNA sequence data for representatives of all extant families. Parakseneuridae were recovered in a clade with Osmylopsychopidae, Prohemerobiidae, and Ithonidae. Conclusions/Significance The presence of the presumed AA1+2 in wings of Parakseneuridae is a unique plesiomorphic condition hitherto unknown in Neuropterida, the clade comprising Neuroptera, Megaloptera, Raphidioptera. The relative uncertainty of phylogenetic position of Parakseneuridae and the majority of other families of Neuroptera reflects deficient paleontological data, especially from critical important periods for the order, earliest Triassic and latest Triassic/earliest Jurassic.", "keyphrases": ["primitive wing venation", "phylogenetic position", "neuropterida", "ithonidae"]}
{"id": "10.1111/1475-4983.00284", "title": "Structure, ontogeny, and moulting of the olenid trilobite Ctenopyge (Eoctenopyge) angusta Westerg\u00e5rd, 1922 from the upper Cambrian of V\u00e4sterg\u00f6tland, Sweden", "abstract": "The genus Ctenopyge is known mainly from disarticulated sclerites and from rare complete specimens flattened in shales. Hitherto, very few specimens have been found preserved intact and in three dimensions. In a recently discovered fauna, however, in the Peltura minor Subzone in V\u00e4sterg\u00f6tland, central Sweden, there occur several species of Ctenopyge, of which many are complete and superbly preserved; moreover they occur at all stages of growth. Of these the abundant Ctenopyge (Eoctenopyge) angusta Westerg\u00e5rd, 1922 is described and reconstructed here as an adult, and the entire ontogeny is documented for all post\u2013protaspid growth stages. Many characters typical of the adult, such as the long genal spines and the caudal spine, develop very early in ontogeny, and the relative dimensions of the cranidium do not greatly change during growth. Macropleural spines, however, develop later. The transitory pygidium, relatively large and shield\u2013shaped in the early meraspid, later becomes very small as the ten thoracic segments are liberated; a median spine develops on the last thoracic segment only at the holaspid stage. Instar groupings can be clearly distinguished for the early stages. Recurrent associations of sclerites are interpreted as moulting configurations. As reconstructed, the genal spines are horizontal and parallel with the extended thorax; an adaptation which presumably allowed the trilobite to rest on the sea floor.", "keyphrases": ["ontogeny", "moulting", "eoctenopyge"]}
{"id": "10.1128/AEM.01332-19", "title": "Membrane Lipid Composition of the Moderately Thermophilic Ammonia-Oxidizing Archaeon \u201cCandidatus Nitrosotenuis uzonensis\u201d at Different Growth Temperatures", "abstract": "For Thaumarchaeota, the ratio of their glycerol dialkyl glycerol tetraether (GDGT) lipids depends on growth temperature, a premise that forms the basis of the widely applied TEX86 paleotemperature proxy. A thorough understanding of which GDGTs are produced by which Thaumarchaeota and what the effect of temperature is on their GDGT composition is essential for constraining the TEX86 proxy. \u201cCa. Nitrosotenuis uzonensis\u201d is a moderately thermophilic thaumarchaeote enriched from a thermal spring, setting it apart in its environmental niche from the other marine mesophilic members of its order. Indeed, we found that the GDGT composition of \u201cCa. Nitrosotenuis uzonensis\u201d cultures was distinct from those of other members of its order and was more similar to those of other thermophilic, terrestrial Thaumarchaeota. This suggests that while phylogeny has a strong influence on GDGT distribution, the environmental niche that a thaumarchaeote inhabits also shapes its GDGT composition. ABSTRACT \u201cCandidatus Nitrosotenuis uzonensis\u201d is the only cultured moderately thermophilic member of the thaumarchaeotal order Nitrosopumilales (NP) that contains many mesophilic marine strains. We examined its membrane lipid composition at different growth temperatures (37\u00b0C, 46\u00b0C, and 50\u00b0C). Its lipids were all membrane-spanning glycerol dialkyl glycerol tetraethers (GDGTs), with 0 to 4 cyclopentane moieties. Crenarchaeol (cren), the characteristic thaumarchaeotal GDGT, and its isomer (cren\u02b9) were present in high abundance (30 to 70%). The GDGT polar headgroups were mono-, di-, and trihexoses and hexose/phosphohexose. The ratio of glycolipid to phospholipid GDGTs was highest in the cultures grown at 50\u00b0C. With increasing growth temperatures, the relative contributions of cren and cren\u02b9 increased, while those of GDGT-0 to GDGT-4 (including isomers) decreased. TEX86 (tetraether index of tetraethers consisting of 86 carbons)-derived temperatures were much lower than the actual growth temperatures, further demonstrating that TEX86 does not accurately reflect the membrane lipid adaptation of thermophilic Thaumarchaeota. As the temperature increased, specific GDGTs changed relative to their isomers, possibly representing temperature adaption-induced changes in cyclopentane ring stereochemistry. Comparison of a wide range of thaumarchaeotal core lipid compositions revealed that the \u201cCa. Nitrosotenuis uzonensis\u201d cultures clustered separately from other members of the NP order and the Nitrososphaerales (NS) order. While phylogeny generally seems to have a strong influence on GDGT distribution, our analysis of \u201cCa. Nitrosotenuis uzonensis\u201d demonstrates that its terrestrial, higher-temperature niche has led to a lipid composition that clearly differentiates it from other NP members and that this difference is mostly driven by its high cren\u02b9 content. IMPORTANCE For Thaumarchaeota, the ratio of their glycerol dialkyl glycerol tetraether (GDGT) lipids depends on growth temperature, a premise that forms the basis of the widely applied TEX86 paleotemperature proxy. A thorough understanding of which GDGTs are produced by which Thaumarchaeota and what the effect of temperature is on their GDGT composition is essential for constraining the TEX86 proxy. \u201cCa. Nitrosotenuis uzonensis\u201d is a moderately thermophilic thaumarchaeote enriched from a thermal spring, setting it apart in its environmental niche from the other marine mesophilic members of its order. Indeed, we found that the GDGT composition of \u201cCa. Nitrosotenuis uzonensis\u201d cultures was distinct from those of other members of its order and was more similar to those of other thermophilic, terrestrial Thaumarchaeota. This suggests that while phylogeny has a strong influence on GDGT distribution, the environmental niche that a thaumarchaeote inhabits also shapes its GDGT composition.", "keyphrases": ["candidatus nitrosotenuis uzonensis", "different growth temperature", "membrane lipid composition"]}
{"id": "10.1126/SCIENCE.AAA3716", "title": "Evolutionary innovation and ecology in marine tetrapods from the Triassic to the Anthropocene", "abstract": "Similar shapes inhabit the sea Over biological history, several different groups of vertebrate tetrapods have reinvaded the marine environment. Although these groups are widely distributed among reptiles, mammals, amphibians, and birds, the shapes they have evolved are remarkably similar. Kelley and Pyenson review the literature on marine vertebrate groups over time and describe the innovations that facilitated the evolution of these marine forms, the environmental conditions that selected for such convergence of form, and the threats they face from future environment change. Science, this issue 10.1126/science.aaa3716 The demands of a marine environment induced similar adaptations across multiple invasions of different vertebrate groups. BACKGROUND More than 30 different lineages of amphibians, reptiles, birds, and mammals have independently invaded oceans ecosystems. Prominent examples include ichthyosaurs and mosasaurs during the Mesozoic (252 to 66 million years ago) and penguins and sea otters during the Cenozoic (66 million years ago to the present). In today\u2019s oceans, marine tetrapods are ecologically important consumers with trophic influence disproportionate to their abundance. They have occupied apex roles in ocean food webs for more than 250 million years, through major changes in ocean and climate, and through mass extinctions. Major paleontological discoveries in the past 40 years have clarified the early land-sea transitions for some marine tetrapods (e.g., whales, sea cows), although the terrestrial origins of many lineages remain obscure. Incipient invasions appear frequently in marine tetrapod history, but such early transitions account for only a small proportion of the total fossil record of successful marine lineages, which in some cases persist for hundreds of millions of years. ADVANCES Marine tetrapods provide ideal models for testing macroevolutionary hypotheses because the repeated transitions between land and sea have driven innovation, convergence, and diversification against a backdrop of changing marine ecosystems and mass extinctions. Recent investigations across a broad range of scales\u2014from molecules to food webs\u2014have clarified the phylogenetic scope, timing, and ecological consequences of these repeated innovations. Studies of the physiology and functional morphology of living species have illuminated the constraints and tradeoffs that shape the pathway of initial marine invasions. Comparative studies on muscle myoglobin concentration or the evolution of sex determination mechanisms, for example, have revealed rampant convergence for these adaptive traits in the marine realm. Exceptionally preserved fossils have also revealed insights into reproductive biology, soft tissue structures, and trophic interactions. Fossils provide critical baselines for understanding historical changes in marine communities and diversity through time, and these baselines remain vital for evaluating the ongoing and severe anthropogenic disturbance to marine tetrapod populations and marine ecosystems as a whole. OUTLOOK Technological advances in remote sensing and biologging will continue to provide crucial insights into the macroecology of marine tetrapods below the water\u2019s edge. Field data, when combined with extensive vouchers represented in museum collections, provide the basis for integrative models of the function and ecology of these logistically challenging organisms. Placed in a phylogenetic comparative framework, these data can enable tests of hypotheses about macroevolutionary patterns. Although perpetually incomplete, new fossil discoveries continue to improve our understanding of the early land-sea transitions in lineages and reveal past ecologies that could not have otherwise been predicted. Emerging imaging, molecular, and isotopic techniques provide an opportunity to expand the investigational scope for studying extinct taxa and to inform our understanding of how living species evolved. Lastly, resolving the full evolutionary scope of marine tetrapod history provides context for the origins of modern ecological patterns and interactions, which are fundamentally being altered by human activities. A unified view of marine tetrapod evolution. Circles mark initial invasions of marine tetrapod groups. Extinct and extant lineages are denoted by open and solid circles, respectively (yellow, amphibians; green, nonavian reptiles; blue, birds; red, mammals). Top curve summarizes marine tetrapod fossil richness through time. Schematic limb drawings demonstrate convergent hydrodynamic forelimbs in marine tetrapods (top to bottom): sea lion, whale, penguin, sea turtle, mosasaur, ichthyosaur. Ma, millions of years ago. Many top consumers in today\u2019s oceans are marine tetrapods, a collection of lineages independently derived from terrestrial ancestors. The fossil record illuminates their transitions from land to sea, yet these initial invasions account for a small proportion of their evolutionary history. We review the history of marine invasions that drove major changes in anatomy, physiology, and ecology over more than 250 million years. Many innovations evolved convergently in multiple clades, whereas others are unique to individual lineages. The evolutionary arcs of these ecologically important clades are framed against the backdrop of mass extinctions and regime shifts in ocean ecosystems. Past and present human disruptions to marine tetrapods, with cascading impacts on marine ecosystems, underscore the need to link macroecology with evolutionary change.", "keyphrases": ["ecology", "marine tetrapod", "mesozoic"]}
{"id": "10.1098/rstb.2015.0282", "title": "Biodiversity\u2013ecosystem functioning relationships in long-term time series and palaeoecological records: deep sea as a test bed", "abstract": "The link between biodiversity and ecosystem functioning (BEF) over long temporal scales is poorly understood. Here, we investigate biological monitoring and palaeoecological records on decadal, centennial and millennial time scales from a BEF framework by using deep sea, soft-sediment environments as a test bed. Results generally show positive BEF relationships, in agreement with BEF studies based on present-day spatial analyses and short-term manipulative experiments. However, the deep-sea BEF relationship is much noisier across longer time scales compared with modern observational studies. We also demonstrate with palaeoecological time-series data that a larger species pool does not enhance ecosystem stability through time, whereas higher abundance as an indicator of higher ecosystem functioning may enhance ecosystem stability. These results suggest that BEF relationships are potentially time scale-dependent. Environmental impacts on biodiversity and ecosystem functioning may be much stronger than biodiversity impacts on ecosystem functioning at long, decadal\u2013millennial, time scales. Longer time scale perspectives, including palaeoecological and ecosystem monitoring data, are critical for predicting future BEF relationships on a rapidly changing planet.", "keyphrases": ["palaeoecological record", "deep sea", "test bed", "time-series data"]}
{"id": "10.1002/ar.a.20360", "title": "Biomechanics of the rostrum in crocodilians: a comparative analysis using finite-element modeling.", "abstract": "This article reports the use of simple beam and finite-element models to investigate the relationship between rostral shape and biomechanical performance in living crocodilians under a range of loading conditions. Load cases corresponded to simple biting, lateral head shaking, and twist feeding behaviors. The six specimens were chosen to reflect, as far as possible, the full range of rostral shape in living crocodilians: a juvenile Caiman crocodilus, subadult Alligator mississippiensis and Crocodylus johnstoni, and adult Caiman crocodilus, Melanosuchus niger, and Paleosuchus palpebrosus. The simple beam models were generated using morphometric landmarks from each specimen. Three of the finite-element models, the A. mississippiensis, juvenile Caiman crocodilus, and the Crocodylus johnstoni, were based on CT scan data from respective specimens, but these data were not available for the other models and so these--the adult Caiman crocodilus, M. niger, and P. palpebrosus--were generated by morphing the juvenile Caiman crocodilus mesh with reference to three-dimensional linear distance measured from specimens. Comparison of the mechanical performance of the six finite-element models essentially matched results of the simple beam models: relatively tall skulls performed best under vertical loading and tall and wide skulls performed best under torsional loading. The widely held assumption that the platyrostral (dorsoventrally flattened) crocodilian skull is optimized for torsional loading was not supported by either simple beam theory models or finite-element modeling. Rather than being purely optimized against loads encountered while subduing and processing food, the shape of the crocodilian rostrum may be significantly affected by the hydrodynamic constraints of catching agile aquatic prey. This observation has important implications for our understanding of biomechanics in crocodilians and other aquatic reptiles.", "keyphrases": ["crocodilian", "finite-element modeling", "assumption", "biomechanic"]}
{"id": "paleo.004397", "title": "Australia's first fossil marsupial mole (Notoryctemorphia) resolves controversies about their evolution and palaeoenvironmental origins", "abstract": "Fossils of a marsupial mole (Marsupialia, Notoryctemorphia, Notoryctidae) are described from early Miocene deposits in the Riversleigh World Heritage Area, northwestern Queensland, Australia. These represent the first unequivocal fossil record of the order Notoryctemorphia, the two living species of which are among the world's most specialized and bizarre mammals, but which are also convergent on certain fossorial placental mammals (most notably chrysochlorid golden moles). The fossil remains are genuinely \u2018transitional', documenting an intermediate stage in the acquisition of a number of specializations and showing that one of these\u2014the dental morphology known as zalambdodonty\u2014was acquired via a different evolutionary pathway than in placentals. They, thus, document a clear case of evolutionary convergence (rather than parallelism) between only distantly related and geographically isolated mammalian lineages\u2014marsupial moles on the island continent of Australia and placental moles on most other, at least intermittently connected continents. In contrast to earlier presumptions about a relationship between the highly specialized body form of the blind, earless, burrowing marsupial moles and desert habitats, it is now clear that archaic burrowing marsupial moles were adapted to and probably originated in wet forest palaeoenvironments, preadapting them to movement through drier soils in the xeric environments of Australia that developed during the Neogene.", "keyphrases": ["marsupial mole", "notoryctemorphia", "australia"]}
{"id": "paleo.012652", "title": "The Still Bay and Howiesons Poort at Sibudu and Blombos: Understanding Middle Stone Age Technologies", "abstract": "The classification of archaeological assemblages in the Middle Stone Age of South Africa in terms of diversity and temporal continuity has significant implications with respect to recent cultural evolutionary models which propose either gradual accumulation or discontinuous, episodic processes for the emergence and diffusion of cultural traits. We present the results of a systematic technological and typological analysis of the Still Bay assemblages from Sibudu and Blombos. A similar approach is used in the analysis of the Howiesons Poort (HP) assemblages from Sibudu seen in comparison with broadly contemporaneous assemblages from Rose Cottage and Klasies River Cave 1A. Using our own and published data from other sites we report on the diversity between stone artifact assemblages and discuss to what extent they can be grouped into homogeneous lithic sets. The gradual evolution of debitage techniques within the Howiesons Poort sequence with a progressive abandonment of the HP technological style argues against the saltational model for its disappearance while the technological differences between the Sibudu and Blombos Still Bay artifacts considerably weaken an interpretation of similarities between the assemblages and their grouping into the same cultural unit. Limited sampling of a fragmented record may explain why simple models of cultural evolution do not seem to apply to a complex reality.", "keyphrases": ["still bay", "howiesons poort", "middle stone age"]}
{"id": "10.1111/j.1096-3642.1999.tb00154.x", "title": "What makes an ophiuroid? A morphological study of the problematic Ordovician stelleroid Stenaster and the palaeobiology of the earliest asteroids and ophiuroids", "abstract": "Abstract Extant asteroids and ophiuroids [Echinodermata] are distinguished by differences in arm support, water vascular system structures and in details of arm and jaw structure. However, some lower Palaeozoic taxa show combinations of both asteroid-like and ophiuroid-like characters and their morphology and functional biology is poorly understood. This paper redescribes one such taxon, the middle-upper Ordovician stellate echinoderm Stenaster and clarifies its phylogenetic status. Characters in common with extant and Ordovician ophiuroids, include arm support due primarily to ambulacral ossicles, presence of extensive longitudinal arm musculature, a mobile jaw and an internalised radial water vessel with internalised podial pores. In addition, Stenaster lacks several characters which are conventionally considered to be asteroid-like, for example an axillary, madreporite, marginal ossicles and a true ambulacral groove. However, in overall shape Stenaster is remarkably asteroid-like, showing short, broad-based arms shared podial basins and a small disc. A cladistic analysis of early asteroids, ophiuroids and somasteroid taxa consistently places Stenaster within the ophiuroids and suggests secondary convergence to asteroids. In functional terms, Stenaster is interpreted as an ophiuroid which has secondarily adopted a semi-infaunal, deposit-feeding mode of life, analogous to that of some extant paxillosid asteroids.", "keyphrases": ["ophiuroid", "stenaster", "early asteroid"]}
{"id": "10.1111/j.1475-4983.2010.01002.x", "title": "A new turtle from the La Colonia Formation (Campanian\u2013Maastrichtian), Patagonia, Argentina, with remarks on the evolution of the vertebral column in turtles", "abstract": "Abstract:\u2002 Patagoniaemys gasparinae gen. et sp. nov. is a new stem turtle found in central Patagonia, Chubut Province, Argentina, in outcrops of the La Colonia Formation (Campanian\u2013Maastrichtian). This is a turtle of relatively large size (carapace length c. 70\u2003cm), and the preserved remains of the holotype consist of skull fragments and several postcranial elements including a nearly complete vertebral column. A phylogenetic analysis shows Patagoniaemys gasparinae gen. et sp. nov. forming a monophyletic group with Otwayemys cunicularius and Mongolochelys efremovi, as a sister group to Meiolaniidae. A comprehensive review confirms that formed cervical vertebrae appeared independently several times during turtle evolution: in the clade that includes Patagoniaemys gasparinae gen. et sp. nov. and Meiolaniidae, in some baenids, in the total group Pleurodira and in crown group Cryptodira. Likewise, formed caudal vertebrae appeared several times in turtle evolution.", "keyphrases": ["turtle", "campanian\u2013maastrichtian", "vertebral column"]}
{"id": "paleo.000241", "title": "A large mimotonid from the Middle Eocene of China sheds light on the evolution of lagomorphs and their kin", "abstract": "Mimotonids share their closest affinity with lagomorphs and were a rare and endemic faunal element of Paleogene mammal assemblages of central Asia. Here we describe a new species, Mimolagus\naurorae from the Middle Eocene of Nei Mongol (China). This species belongs to one of the most enigmatic genera of fossil Glires, previously known only from the type and only specimen from the early Oligocene of Gansu (China). Our finding extends the earliest occurrence of the genus by at least 10 million years in the Paleogene of Asia, which closes the gap between Mimolagus and other mimotonids that are known thus far from middle Eocene or older deposits. The new species is one of the largest known pre-Oligocene Glires. As regards duplicidentates, Mimolagus is comparable with the largest Neogene continental leporids, namely hares of the genus Lepus. Our results suggest that ecomorphology of this species was convergent on that of small perissodactyls that dominated faunas of the Mongolian Plateau in the Eocene, and probably a result of competitive pressure from other Glires, including a co-occurring mimotonid, Gomphos.", "keyphrases": ["mimotonid", "middle eocene", "lagomorph"]}
{"id": "paleo.008592", "title": "An antiarch placoderm shows that pelvic girdles arose at the root of jawed vertebrates", "abstract": "Almost all gnathostomes or jawed vertebrates (including osteichthyans, chondrichthyans, \u2018acanthodians\u2019 and most placoderms) possess paired pectoral and pelvic fins. To date, it has generally been believed that antiarch placoderms (extinct armoured jawed fishes from the Silurian\u2013Devonian periods) lacked pelvic fins. The putative absence of pelvic fins is a key character bearing on the monophyly or paraphyly of placoderms. It also has far-reaching implications for studying the sequence of origin of pelvic girdles versus that of movable jaws in the course of vertebrate evolution. Parayunnanolepis xitunensis represents the only example of a primitive antiarch with extensive post-thoracic preservation, and its original description has been cited as confirming the primitive lack of pelvic fins in early antiarchs. Here, we present a revised description of Parayunnanolepis and offer the first unambiguous evidence for the presence of pelvic girdles in antiarchs. As antiarchs are placed at the base of the gnathostome radiation in several recent studies, our finding shows that all jawed vertebrates (including antiarch placoderms) primitively possess both pectoral and pelvic fins and that the pelvic fins did not arise within gnathostomes at a point subsequent to the origin of jaws.", "keyphrases": ["antiarch placoderm", "pelvic girdle", "osteichthyan"]}
{"id": "10.3732/ajb.94.9.1534", "title": "Seed morphology of modern and fossil Ampelocissus (Vitaceae) and implications for phytogeography.", "abstract": "Seeds are useful in distinguishing among extant genera of Vitaceae and provide a good basis for interpretation of fossil remains in reconstructing the evolutionary and phytogeographic history of this putatively basal Rosid family. Seeds of Ampelocissus s.l. including Pterisanthes and Nothocissus are distinguished from those of all other vitaceous genera by long, parallel ventral infolds and a centrally positioned oval chalazal scar. Principal component analysis facilitates recognition of four Ampelocissus s.l. seed morphotypes differentiated by dorsiventral thickness, width of ventral infolds, chalazal depth, and degree of dorsal surface rugosity. While these intergrade, their end-member morphologies are distinctive and coincide well with inflorescence morphology, extant geographic distribution, and ecology. Seven fossil morphospecies are recognized. Ampelocissus parvisemina sp. n. (Paleocene of North Dakota; Eocene of Oregon) and A. auriforma Manchester (Eocene of Oregon) resemble extant Central American species; A. bravoi Berry (Eocene of Peru) is similar to one group of Old World extant species; and A. parachandleri sp. n. (Eocene of Oregon) and the three European fossil species A. chandleri (Kirchheimer) comb. n., A. lobatum (Chandler) comb. n., and A. wildei sp. n. (Eocene to Miocene) resemble another group of extant Old World Ampelocissus. All these fossils occur outside the present geographic range of the genus, reflecting warmer climates and former intercontinental links.", "keyphrases": ["vitaceae", "ventral infold", "oval chalazal scar", "seed"]}
{"id": "10.1130/G32785.1", "title": "Clay assemblage and oxygen isotopic constraints on the weathering response to the Paleocene-Eocene thermal maximum, east coast of North America", "abstract": "The Paleocene-Eocene thermal maximum, a transient global warming event, is character- ized by extensive evidence of a more active hydrological cycle. This includes a widespread pulse of kaolinite accumulation on continental margins, viewed as the by-product of either enhanced chemical weathering consistent with much more humid conditions and/or increased erosion of previously deposited laterites. The former would be more consistent with year- round humid conditions, whereas the latter might be indicative of extreme seasonal precipi- tation patterns. To assess these hypotheses, we present a new high-resolution clay mineral assemblage and oxygen isotope record from Bass River, a site on the New Jersey margin (east coast of North America), which shows a sharp rise in the abundance of kaolinite beginning a few thousand years before the onset of the carbon isotope excursion (CIE). The \u03b4 18 O of the <2-\u00b5m-size fraction exhibits a shift toward lower values during the event. On the basis of a coeval shift in clay assemblages, the shift in \u03b4 18 O Clays can be explained by a shift in the relative percent of the primary clay phases rather than a change in the isotopic composition of kaolinite, as would be expected if the kaolinite had been produced primarily during the Paleocene-Eocene thermal maximum. This fi nding points to accelerated exhumation and ero- sion of kaolinitic soils, most likely Cretaceous laterites.", "keyphrases": ["paleocene-eocene thermal maximum", "east coast", "chemical weathering", "clay assemblage"]}
{"id": "10.1017/jpa.2017.78", "title": "Craniodental morphology and diet of Leptarctus oregonensis (Mammalia, Carnivora, Mustelidae) from the Mascall Formation (Miocene) of central Oregon", "abstract": "Abstract. \n The Leptarctinae are an enigmatic subfamily of mustelids present in North America and Eurasia during the Miocene (Arikareean to Hemphillian North American Land Mammal Ages). Their diet and ecology have been particularly controversial. Some workers have suggested they were similar to koalas, whereas others suggested they were crushing omnivores analogous to raccoons. Leptarctus oregonensis Stock, 1930, a poorly known leptarctine from the early Barstovian, is represented by fragmented cranial elements and isolated teeth from the Mascall Formation of Oregon, and some fairly complete but undescribed material from the Olcott Formation of western Nebraska. Herein, we describe the first well-preserved skull of L. oregonensis from the type formation. Based on this new specimen, we confirm that L. oregonensis is a distinct species from L. primus Leidy, 1856 and L. ancipidens White, 1941 that is characterized by a distinct morphology of its tympanic projections and first upper molars. We are also able to describe intraspecific variation within L. oregonensis coinciding with the geographic distribution of the specimens (Oregon and Nebraska). The most variable characters are concentrated in the morphology of the frontals and the upper fourth premolar. Additional specimens will be needed to settle the debate over sexual dimorphism in this species, but this new specimen suggests that Leptarctus oregonensis, despite being one of the smallest members of the Leptarctinae, was an animal-dominated omnivore with considerable crushing ability.", "keyphrases": ["leptarctus oregonensis", "carnivora", "miocene"]}
{"id": "10.3390/geosciences4010001", "title": "Cretaceous-Paleogene Dinoflagellate Biostratigraphy and the Age of the Clayton Formation, Southeastern Missouri, USA", "abstract": "Sedimentary deposits in Stoddard County, southeastern Missouri, reveal a K-Pg transition sequence represented by the uppermost Maastrichtian Owl Creek Formation and the Paleocene Clayton Formation. The Clayton Formation is characterized by a basal fossiliferous coquinite that contains reworked late Maastrichtian macrofossils. Dinoflagellate biostratigraphy is used to determine the age of the coquinite layer and specifically whether or not it is an end-K tsunamite deposit resulting from the Chicxulub impact event. Results indicate a mixed assemblage of late Maastrichtian and early Danian dinocysts within the basal coquinite of the Clayton Formation. Maastrichtian dinocyst taxa identified are Riculacysta amplexa, Pierceites pentagonus, Phelodinium tricuspe and Dinogymnium sp. and dinocysts utilized as global indicators of the basal Danian, also present in the coquinite, consist of Senoniasphaera inornata, Carpatella cornuta, Damassadinium californicum, and Lanternosphaeridium reinhardtii. A gray mud occurring above the coquinite in the middle of the Clayton Formation contains the mid-Danian dinoflagellate Senegalinium iterlaaense. Collectively, these data suggest that the coquinite was deposited well after the K-Pg event but before the middle Danian. The mixed assemblage of Late Cretaceous and Paleocene dinocysts preserved in the coquinite weakens the hypothesis that it is an end-K tsunamite deposit and suggests instead that it may result from a long-term transgressive lag. We also extend the stratigraphic range of the Paleocene Senegalinium simplex downward into the uppermost Maastrichtian.", "keyphrases": ["dinoflagellate biostratigraphy", "clayton formation", "owl creek formation"]}
{"id": "paleo.005481", "title": "Evolution of reproductive strategies in dictyopteran insects \u2013 clues from ovipositor morphology of extinct roachoids", "abstract": "Dictyoptera, which comprises cockroaches, termites and mantids, is a quite successful group of insects in evolutionary terms with a long fossil record\u2014roachoid insects were already abundant 315 million years ago in the Carboniferous forests. One of the most remarkable autapomorphies of extant dictyopterans, and possibly a major factor for their persisting success, is the ability to produce oothecae. Despite the robustness of this sort of egg package, fossils of oothecae are very rare, the oldest direct evidences being from the Cretaceous Crato Formation in Brazil (115 mya). The ability to produce oothecae is presumably linked to a specific ovipositor morphology, including a significant length reduction. Hence, ovipositor morphology can indirectly inform about the reproductive strategy of a species. Herein we describe the ovipositor morphology of various fossil forms of dictyopteran insects. Early fossil roachoids, in contrast to the modern forms, possessed a very long and prominent ovipositor, reminiscent of the ovipositor in orthopterans (Ensifera), indicating that these forms laid individual, rather small eggs into a substrate. We present examples from different fossil deposits, which show the entire range of ovipositor morphologies, from very long forms over forms with ovipositors partly reduced in length to modern-appearing morphologies. Most remarkably, different shapes of ovipositors seem to be present in roachoids in the fauna of the 115 million years old Crato Formation\u2014species with long prominent ovipositors co-existed with species with a reduced short and broad ovipositor. Additionally, females that carry oothecae attached to their abdomen indicate a third type of ovipositor: a further reduced ovipositor as seen in modern forms, which already allowed the internal production of oothecae.", "keyphrases": ["reproductive strategy", "dictyopteran insect", "ovipositor morphology", "cockroach", "abdoman"]}
{"id": "paleo.006954", "title": "Dental microwear texture reflects dietary tendencies in extant Lepidosauria despite their limited use of oral food processing", "abstract": "Lepidosauria show a large diversity in dietary adaptations, both among extant and extinct tetrapods. Unlike mammals, Lepidosauria do not engage in sophisticated mastication of their food and most species have continuous tooth replacement, further reducing the wear of individual teeth. However, dietary tendency estimation of extinct lepidosaurs usually rely on tooth shape and body size, which allows only for broad distinction between faunivores and herbivores. Microscopic wear features on teeth have long been successfully applied to reconstruct the diet of mammals and allow for subtle discrimination of feeding strategies and food abrasiveness. Here, we present, to our knowledge, the first detailed analysis of dental microwear texture on extant lepidosaurs using a combination of 46 surface texture parameters to establish a framework for dietary tendency estimation of fossil reptilian taxa. We measured dental surface textures of 77 specimens, belonging to herbivorous, algaevorous, frugivorous, carnivorous, ovivorous, insectivorous, molluscivorous, as well as omnivorous species. Carnivores show low density and shallow depth of furrows, whereas frugivores are characterized by the highest density of furrows. Molluscivores show the deepest wear features and highest roughness, herbivores have lower surface roughness and shallower furrows compared to insectivores and omnivores, which overlap in all parameters. Our study shows that despite short food\u2013tooth interaction, dental surface texture parameters enable discrimination of several feeding strategies in lepidosaurs. This result opens new research avenues to assess diet in a broad variety of extant and extinct non-mammalian taxa including dinosaurs and early synapsids.", "keyphrases": ["lepidosauria", "dental microwear texture", "reptile", "dietary guild", "dmta"]}
{"id": "paleo.012648", "title": "Influence of Microbial Biofilms on the Preservation of Primary Soft Tissue in Fossil and Extant Archosaurs", "abstract": "Background Mineralized and permineralized bone is the most common form of fossilization in the vertebrate record. Preservation of gross soft tissues is extremely rare, but recent studies have suggested that primary soft tissues and biomolecules are more commonly preserved within preserved bones than had been presumed. Some of these claims have been challenged, with presentation of evidence suggesting that some of the structures are microbial artifacts, not primary soft tissues. The identification of biomolecules in fossil vertebrate extracts from a specimen of Brachylophosaurus canadensis has shown the interpretation of preserved organic remains as microbial biofilm to be highly unlikely. These discussions also propose a variety of potential mechanisms that would permit the preservation of soft-tissues in vertebrate fossils over geologic time. Methodology/Principal Findings This study experimentally examines the role of microbial biofilms in soft-tissue preservation in vertebrate fossils by quantitatively establishing the growth and morphology of biofilms on extant archosaur bone. These results are microscopically and morphologically compared with soft-tissue extracts from vertebrate fossils from the Hell Creek Formation of southeastern Montana (Latest Maastrichtian) in order to investigate the potential role of microbial biofilms on the preservation of fossil bone and bound organic matter in a variety of taphonomic settings. Based on these analyses, we highlight a mechanism whereby this bound organic matter may be preserved. Conclusions/Significance Results of the study indicate that the crystallization of microbial biofilms on decomposing organic matter within vertebrate bone in early taphonomic stages may contribute to the preservation of primary soft tissues deeper in the bone structure.", "keyphrases": ["microbial biofilm", "primary soft tissue", "organic matter", "crystallization", "vertebrate bone"]}
{"id": "10.1098/rspb.2001.1877", "title": "A Gondwanan origin of passerine birds supported by DNA sequences of the endemic New Zealand wrens", "abstract": "Zoogeographic, palaeontological and biochemical data support a Southern Hemisphere origin for passerine birds, while accumulating molecular data suggest that most extant avian orders originated in the mid\u2013Late Cretaceous. We obtained DNA sequence data from the nuclear c\u2013myc and RAG\u20131 genes of the major passerine groups and here we demonstrate that the endemic New Zealand wrens (Acanthisittidae) are the sister taxon to all other extant passerines, supporting a Gondwanan origin and early radiation of passerines. We propose that (i) the acanthisittids were isolated when New Zealand separated from Gondwana (ca. 82\u201385 Myr ago), (ii) suboscines, in turn, were derived from an ancestral lineage that inhabited western Gondwana, and (iii) the ancestors of the oscines (songbirds) were subsequently isolated by the separation of Australia from Antarctica. The later spread of passerines into the Northern Hemisphere reflects the northward migration of these former Gondwanan elements.", "keyphrases": ["gondwanan origin", "passerine bird", "new zealand wren"]}
{"id": "10.1002/9781118452547.ch34", "title": "A protocol for a geological sea-level database", "abstract": "A sea-level index point (SLIP) estimates relative sea level (RSL) at a specified time and place, with an associated uncertainty. In the preceding chapters, numerous examples have been provided detailing how to collect sea-level indicators from different geomorphic settings (Chapters 3\u201310) and the means to interpret them (Chapters 12\u201322). Various methods of dating SLIPs (Chapters 23\u201327) have been discussed, as well as how to use modeling to account for compaction or changes in tidal range (Chapters 29 and 30). In order to compare SLIPs collected by differing techniques, it is necessary to analyze their associated errors in an objective and uniform way. SLIPs that are represented as discrete, errorless data points in age/ elevation space may lead to erroneous inferences of RSL fluctuations that often reflect inherent uncertainties in the underlying data. The usefulness of geological sea-level data increases significantly if they are subjected to a rigorous error analysis with well-quantified uncertainties. As a consequence, SLIPs have played a major role in the last decades in estimating future sea-level change by establishing long-term background rates of vertical land motion (e.g., Engelhart et al., 2009) and in refining glacial isostatic adjustment (GIA) models (e.g., Lambeck et al., 1998; Peltier et al., 2002; Milne et al., 2005; Vink et al., 2007). The database approach is a method for analyzing large numbers of SLIPs with all data stored according to a well-defined error protocol. A sea-level database can elucidate regional variations in past RSL which are of interest to a wide range of topics such as ice-sheet dynamics, archeology, Earth rheology, and future sea-level change. Multiple approaches to database construction have been used worldwide (e.g., Flemming, 1982; Shennan and Horton, 2002; Toscano and Macintyre, 2003; Dutton and Lambeck, 2012; Engelhart and Horton, 2012; Yu et al., 2012), all with unique strategies and emphases. In this chapter we present a comprehensive protocol for analyzing and standardizing sealevel data, including a format for constructing a sea-level database that captures all the relevant variables. In particular, we build on the work initiated by the Durham University group in the 1980s (e.g., Shennan, 1989) that culminated in a comprehensive sea-level database for the UK (Shennan and Horton, 2002). The hallmark of the UK sea-level database is the evaluation in a systematic fashion of a large range of variables to produce SLIPs and limiting data points. Here we expand upon this approach, especially by quantifying dating errors and by incorporating both modern-day and paleotidal modeling. The overarching philosophy is to include as much of the original, \u201craw\u201d data as possible, and to maximize caution in assigning errors. The latter implies that assigned errors are often larger than in previous analyses of similar data. The database described here was developed within the framework of studies of RSL change since the Last Glacial Maximum (LGM) along the US Gulf and Atlantic coasts. However, the methods can be applied worldwide as they are suitable for a Chapter 34 A protocol for a geological sea-level database", "keyphrases": ["protocol", "geological sea-level database", "uncertainty"]}
{"id": "10.2475/ajs.294.1.56", "title": "Geocarb III: A Revised Model of Atmospheric CO2 over Phanerozoic Time", "abstract": "Revision of the GEOCARB model (Berner, 1991, 1994) for paleolevels of atmospheric CO2, has been made with emphasis on factors affecting CO2 uptake by continental weathering. This includes: (1) new GCM (general circulation model) results for the dependence of global mean surface temperature and runoff on CO2, for both glaciated and non-glaciated periods, coupled with new results for the temperature response to changes in solar radiation; (2) demonstration that values for the weathering-uplift factor fR(t) based on Sr isotopes as was done in GEOCARB II are in general agreement with independent values calculated from the abundance of terrigenous sediments as a measure of global physical erosion rate over Phanerozoic time; (3) more accurate estimates of the timing and the quantitative effects on Ca-Mg silicate weathering of the rise of large vascular plants on the continents during the Devonian; (4) inclusion of the effects of changes in paleogeography alone (constant CO2 and solar radiation) on global mean land surface temperature as it affects the rate of weathering; (5) consideration of the effects of volcanic weathering, both in subduction zones and on the seafloor; (6) use of new data on the d 13 C values for Phanerozoic limestones and organic matter; (7) consideration of the relative weather- ing enhancement by gymnosperms versus angiosperms; (8) revision of paleo land area based on more recent data and use of this data, along with GCM-based paleo-runoff results, to calculate global water discharge from the continents over time. Results show a similar overall pattern to those for GEOCARB II: very high CO2 values during the early Paleozoic, a large drop during the Devonian and Carbonifer- ous, high values during the early Mesozoic, and a gradual decrease from about 170 Ma to low values during the Cenozoic. However, the new results exhibit considerably higher CO2 values during the Mesozoic, and their downward trend with time agrees with the independent estimates of Ekart and others (1999). Sensitivity analysis shows that results for paleo-CO2 are especially sensitive to: the effects of CO2 fertilization and temperature on the acceleration of plant-mediated chemical weathering; the quantitative effects of plants on mineral dissolution rate for constant temperature and CO2; the relative roles of angiosperms and gymnosperms in accelerating rock weather- ing; and the response of paleo-temperature to the global climate model used. This emphasizes the need for further study of the role of plants in chemical weathering and the application of GCMs to study of paleo-CO2 and the long term carbon cycle.", "keyphrases": ["atmospheric co2", "phanerozoic time", "geocarb model"]}
{"id": "paleo.001288", "title": "A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation", "abstract": "The terrestrial Judith River Formation of northern Montana was deposited over an approximately 4 Myr interval during the Campanian (Late Cretaceous). Despite having been prospected and collected continuously by palaeontologists for over a century, few relatively complete dinosaur skeletons have been recovered from this unit to date. Here we describe a new genus and species of ankylosaurine dinosaur, Zuul crurivastator, from the Coal Ridge Member of the Judith River Formation, based on an exceptionally complete and well-preserved skeleton (ROM 75860). This is the first ankylosaurin skeleton known with a complete skull and tail club, and it is the most complete ankylosaurid ever found in North America. The presence of abundant soft tissue preservation across the skeleton, including in situ osteoderms, skin impressions and dark films that probably represent preserved keratin, make this exceptional skeleton an important reference for understanding the evolution of dermal and epidermal structures in this clade. Phylogenetic analysis recovers Zuul as an ankylosaurin ankylosaurid within a clade of Dyoplosaurus and Scolosaurus, with Euoplocephalus being more distantly related within Ankylosaurini. The occurrence of Z. crurivastator from the upper Judith River Formation fills a gap in the ankylosaurine stratigraphic and geographical record in North America, and further highlights that Campanian ankylosaurines were undergoing rapid evolution and stratigraphic succession of taxa as observed for Laramidian ceratopsids, hadrosaurids, pachycephalosaurids and tyrannosaurids.", "keyphrases": ["ankylosaurine dinosaur", "judith river formation", "exceptional skeleton"]}
{"id": "10.1666/09-035.1", "title": "A Revision of Plesiobaena (Testudines: Baenidae) and an Assessment of Baenid Ecology Across the K/T Boundary", "abstract": "Abstract Over the course of the last two decades, the baenid taxon Plesiobaena has typically been thought to consist of two named species, Plesiobaena antiqua (Campanian) and Plesiobaena putorius (Paleocene), along with an unnamed species from the Maastrichtian, but the interrelationship of these three taxa was never explored in an explicit phylogenetic context. Herein we present or re-describe a number of relevant specimens and provide a cladistic analysis of Baenidae using species only as terminal taxa. The phylogenetic analysis clearly reveals that Plesiobaena in the traditional sense is a paraphyletic assemblage relative to the clade formed by Gamerabaena sonsalla and Palatobaena spp., thus demanding some nomenclatural adjustments. In particular, Plesiobaena putorius is moved to a new genus, Cedrobaena, and the unnamed taxon from the Maastrichtian is formally named Peckemys brinkman. Many of the new Cedrobaena putorius and Peckemys brinkman specimens described herein were found at the Turtle Graveyard locality in Slope County, North Dakota, along with four other turtle taxa, increasing the turtle diversity of this locality to at least six taxa. Although this indicates that Turtle Graveyard is the world's most diverse fossil turtle thanatocoenosis, a comparable diversity is found in modern river systems in the southeastern United States today. Our phylogenetic analysis indicates that seven out of nine latest Cretaceous baenid turtle lineages survived into the Paleocene, four of which are interpreted as being durophagous.", "keyphrases": ["plesiobaena", "baenidae", "phylogenetic analysis"]}
{"id": "10.1029/94jc01882", "title": "The long\u2010lived mollusc Arctica islandica: A new paleoceanographic tool for the reconstruction of bottom temperatures for the continental shelves of the northern North Atlantic Ocean", "abstract": "The carbonate shell of the bivalve Arctica islandica has been recognized, for more than a decade, as a potentially important marine geochemical biorecorder owing to this species' great longevity (200+ years) and wide geographic distribution throughout the northern North Atlantic Ocean, a region vital to global climate and ocean circulation. However, until now this potential has not been realized owing to the difficulty of precisely sampling the shell of this slow growing species. Using newly available automated microsampling techniques combined with micromass stable isotope mass spectrometry, a stable oxygen isotope record (1956\u20131957 and 1961\u20131970) has been obtained from a live-captured, 38-year-old A. islandica specimen collected near the former position of the Nantucket Shoals Lightship (41\u00b0N. 69\u00b0W). The shell's \u03b418O signal is compared with an expected signal derived from ambient bottom temperature and salinity data recorded at the lightship for the same period. The results show that A islandica's \u03b418O record (1) is in phase with its growth banding, confirming the annual periodicity of this species' growth bands, (2) is in oxygen isotopic equilibrium with the ambient seawater, (3) shows a consistent shell growth shutdown temperature of \u223c6\u00b0C. which translates into an \u223c8-month (May\u2013December) shell growth period at this location, and (4) records the ambient bottom temperature with a precision of \u223c\u00b11.2\u00b0C. These results add important information on the life history of this commercially important shellfish species and demonstrate that A. islandica shells can be used to reconstruct inter- and intra-annual records of the continental shelf bottom temperature.", "keyphrases": ["bottom temperature", "north atlantic ocean", "oxygen", "continental shelf"]}
{"id": "10.1002/spp2.1259", "title": "Redescription of Arganasaurus (Metoposaurus) azerouali (Dutuit) comb. nov. from the Upper Triassic of the Argana Basin (Morocco), and the first phylogenetic analysis of the Metoposauridae (Amphibia, Temnospondyli)", "abstract": "A systematic revision of the temnospondyl \u2018Metoposaurus\u2019 azerouali Dutuit from the Late Triassic of the Argana Basin (Western High Atlas, Morocco) is presented. The type material is redescribed in detail, and a preliminary phylogenetic analysis \u2013 the first one dealing with all metoposaurid species \u2013 is also conducted in order to test its position within the Metoposauridae. Our analysis places \u2018Metoposaurus\u2019 azerouali as sister\u2010taxon to Arganasaurus lyazidi in a robust clade supported by two unambiguous synapomorphies (bulge\u2010like tabular horn and exoccipital process visible in dorsal view) and two ambiguous synapomorphies (cultriform process of uniform width and subtriangular posterior Meckelian fenestra). We therefore propose the new combination Arganasaurus azerouali comb. nov. for the species \u2018M.\u2019 azerouali. Our analysis also confirms that the central Laurasian genus Metoposaurus is monophyletic but not the genus Koskinonodon, which deserves its own systematic revision. By consequent, the Late Triassic rich vertebrate fauna from the Argana Basin comprises the metoposauroid Almasaurus habazzi, the basal metoposaurid Dutuitosaurus ouazzoui, and the genus Arganasaurus which is represented by the type species A. lyazidi and A. azerouali comb. nov. Combined with the stratigraphical and geographical occurrences of the taxa, our phylogenetic analysis suggests that metoposaurids may have appeared during the Longobardian (late Ladinian) in central Pangea. Their diversification may be linked to the Carnian Pluvial Episode. At least, their extinction may have occurred during the Rhaetian because of the aridification of the climate and/or competition with amniotes.", "keyphrases": ["argana basin", "phylogenetic analysis", "metoposauridae"]}
{"id": "paleo.009649", "title": "Molecular Decay of the Tooth Gene Enamelin (ENAM) Mirrors the Loss of Enamel in the Fossil Record of Placental Mammals", "abstract": "Vestigial structures occur at both the anatomical and molecular levels, but studies documenting the co-occurrence of morphological degeneration in the fossil record and molecular decay in the genome are rare. Here, we use morphology, the fossil record, and phylogenetics to predict the occurrence of \u201cmolecular fossils\u201d of the enamelin (ENAM) gene in four different orders of placental mammals (Tubulidentata, Pholidota, Cetacea, Xenarthra) with toothless and/or enamelless taxa. Our results support the \u201cmolecular fossil\u201d hypothesis and demonstrate the occurrence of frameshift mutations and/or stop codons in all toothless and enamelless taxa. We then use a novel method based on selection intensity estimates for codons (\u03c9) to calculate the timing of iterated enamel loss in the fossil record of aardvarks and pangolins, and further show that the molecular evolutionary history of ENAM predicts the occurrence of enamel in basal representatives of Xenarthra (sloths, anteaters, armadillos) even though frameshift mutations are ubiquitous in ENAM sequences of living xenarthrans. The molecular decay of ENAM parallels the morphological degeneration of enamel in the fossil record of placental mammals and provides manifest evidence for the predictive power of Darwin's theory.", "keyphrases": ["enamel", "placental mammal", "aardvark", "sloth", "molecular decay"]}
{"id": "10.1029/2006PA001391", "title": "Coupling of millennial\u2010scale changes in sea surface temperature and precipitation off northeastern Brazil with high\u2010latitude climate shifts during the last glacial period", "abstract": "[1]\u00a0High-resolution records of alkenone-derived sea surface temperatures and elemental Ti/Ca ratios from a sediment core retrieved off northeastern Brazil (4\u00b0S) reveal short-term climate variability throughout the past 63,000 a. Large pulses of terrigenous sediment discharge, caused by increased precipitation in the Brazilian hinterland, coincide with Heinrich events and the Younger Dryas period. Terrigenous input maxima related to Heinrich events H6\u2013H2 are characterized by rapid cooling of surface water ranging between 0.5\u00b0 and 2\u00b0C. This signature is consistent with a climate model experiment where a reduction of the Atlantic meridional overturning circulation (AMOC) and related North Atlantic cooling causes intensification of NE trade winds and a southward movement of the Intertropical Convergence Zone, resulting in enhanced precipitation off northeastern Brazil. During deglaciation the surface temperature evolution at the core site predominantly followed the Antarctic warming trend, including a cooling, prior to the Younger Dryas period. An abrupt temperature rise preceding the onset of the Bolling/Allerod transition agrees with model experiments suggesting a Southern Hemisphere origin for the abrupt resumption of the AMOC during deglaciation caused by Southern Ocean warming and associated with northward flow anomalies of the South Atlantic western boundary current.", "keyphrases": ["sea surface temperature", "precipitation", "northeastern brazil", "sediment core"]}
{"id": "paleo.008472", "title": "Global late Quaternary megafauna extinctions linked to humans, not climate change", "abstract": "The late Quaternary megafauna extinction was a severe global-scale event. Two factors, climate change and modern humans, have received broad support as the primary drivers, but their absolute and relative importance remains controversial. To date, focus has been on the extinction chronology of individual or small groups of species, specific geographical regions or macroscale studies at very coarse geographical and taxonomic resolution, limiting the possibility of adequately testing the proposed hypotheses. We present, to our knowledge, the first global analysis of this extinction based on comprehensive country-level data on the geographical distribution of all large mammal species (more than or equal to 10 kg) that have gone globally or continentally extinct between the beginning of the Last Interglacial at 132 000 years BP and the late Holocene 1000 years BP, testing the relative roles played by glacial\u2013interglacial climate change and humans. We show that the severity of extinction is strongly tied to hominin palaeobiogeography, with at most a weak, Eurasia-specific link to climate change. This first species-level macroscale analysis at relatively high geographical resolution provides strong support for modern humans as the primary driver of the worldwide megafauna losses during the late Quaternary.", "keyphrases": ["quaternary megafauna extinction", "climate change", "mammal specie", "pleistocene"]}
{"id": "10.1017/jpa.2017.44", "title": "Revision of the oryctocephalid trilobite genera Arthricocephalus Bergeron and Oryctocarella Tomashpolskaya and Karpinski (Cambrian) from South China and Siberia", "abstract": "Abstract. \n Restudy of the limestone slab containing the type suite of Arthricocephalus chauveaui Bergeron, 1899 (Trilobita), the type species of Arthricocephalus Bergeron, 1899, shows that specimens of three species, each representing a separate genus, are present on the slab and were likely included in the original concept of the species. Besides A. chauveaui, the slab contains specimens of Oryctocarella duyunensis (Qian, 1961) and Duyunaspis duyunensis Zhang and Qian in Zhou et al., 1977. Bergeron (1899) illustrated one exoskeleton from the type suite of A. chauveaui only and apparently based much of his written description on that specimen. This specimen was clearly intended to be the type specimen of A. chauveaui. Subsequently, Lane et al. (1988) designated another specimen, which was not originally illustrated, as the lectotype, and this specimen is referable to Oryctocarella duyunensis. As revised here, Bergeron's illustrated specimen should be regarded as the lectotype of A. chauveaui. Such designation stabilizes the concepts of both Arthricocephalus and A. chauveaui. Arthricocephalites Qian in Lu et al., 1974 and Haliplanktos Blaker and Peel, 1997 are regarded as junior synonyms of Arthricocephalus. Oryctocarella Tomashpolskaya and Karpinski, 1961, which was previously regarded as a junior synonym of Arthricocephalus, is revived as a valid genus. Oryctocarella includes a number of species previously assigned to Arthricocephalus. The type species of both Arthricocephalus and Oryctocarella, together with related species, are described on the basis of new material.", "keyphrases": ["oryctocarella tomashpolskaya", "karpinski", "south china", "balangia"]}
{"id": "10.1002/spp2.1347", "title": "Small carbonaceous fossils (SCFs) from North Greenland: new light on metazoan diversity in early Cambrian shelf environments", "abstract": "The Sirius Passet Lagerst\u00e4tte of North Greenland is one of the oldest records of soft\u2010bodied metazoan\u2010dominated ecosystems from the early Cambrian. The Lagerst\u00e4tte site itself is restricted to just a single c. 1\u2010km\u2010long outcrop located offshore from the shelf margin, in an area affected by metamorphic alteration during the Ellesmerian Orogeny (Devonian \u2013 Early Carboniferous). The recent recovery of small carbonaceous fossils (SCFs) to the south, in areas that escaped the effects of this deformation, has substantially expanded the known coverage of organic preservation into shallower water depositional settings in this region. Here, we describe additional SCF assemblages from the siliciclastic shelf succession of the Buen Formation (Cambrian Series 2, stages 3\u20134; c. 515 Ma), expanding the previously documented SCF biota. Newly recovered material indicates a rich diversity of non\u2010mineralizing metazoans, chiefly represented by arthropod remains. These include the filtering and grinding elements of a sophisticated crustacean feeding apparatus (the oldest crustacean remains reported to date), alongside an assortment of bradoriid sclerites, including almost complete, 3D valves, which tie together a number of SCFs previously found in isolation. Other metazoan remains include various trilobite cuticles, diverse scalidophoran sclerites, and a range of metazoan fragments of uncertain affinity. This shallower water assemblage differs substantially from the Sirius Passet biota, which is dominated by problematic euarthropod stem\u2010group members and sponges. Although some of these discrepancies are attributable to taphonomic or temporal factors, these lateral variations in taxonomic composition also point to significant palaeoenvironmental and/or palaeoecological controls on early Cambrian metazoan communities.", "keyphrases": ["north greenland", "cambrian series", "small carbonaceous fossil"]}
{"id": "paleo.004951", "title": "A new varanopid synapsid from the early Permian of Oklahoma and the evolutionary stasis in this clade", "abstract": "Varanopids are a basal clade of small- to medium-sized non-therapsid synapsids, whose range extends from the late Pennsylvanian to the late middle Permian, and are found in North America, Russia, Europe and South Africa. The greatest varanopid diversity is observed at the fossiliferous cave deposits near Richards Spur, Oklahoma, well known for the preservation of a complex early Permian upland community. Two previously described varanopids, Mycterosaurus and Varanops, are known only from fragmentary disarticulated material at Richards Spur. A third putative varanopid, Basicranodon fortsillensis, represented by a partial parasphenoid, has been synonymized with Mycterosaurus longiceps. This study reports on a new varanopid taxon, represented by substantially more complete material, including three nearly complete skulls. Such comprehensive cranial material allows for a detailed study of the taxon and its relationship to other varanopids. This new varanopid bears great morphological similarity to Mesenosaurus romeri from the middle Permian Mezen River Basin of northern Russia. Phylogenetic analysis recovers a sister relationship between this taxon and Me. romeri. This relationship, in conjunction with a detailed morphological comparison, supports the placement of this taxon within Mesenosaurus, as a new species, Me. efremovi. These results reveal an unexpected extension of the geographical and temporal range of Mesenosaurus, contributing to our understanding of varanopid dispersal. The extended persistence of this basal clade of predatory synapsids, underscored by the apparent evolutionary stasis of this genus, is unusual among Palaeozoic tetrapods. This phenomenon implies an exceptionally high degree of extended ecological resilience across major faunal and environmental transitions.", "keyphrases": ["varanopid", "permian", "evolutionary stasis"]}
{"id": "paleo.010542", "title": "Lichen mimesis in mid-Mesozoic lacewings", "abstract": "Animals mimicking other organisms or using camouflage to deceive predators are vital survival strategies. Modern and fossil insects can simulate diverse objects. Lichens are an ancient symbiosis between a fungus and an alga or a cyanobacterium that sometimes have a plant-like appearance and occasionally are mimicked by modern animals. Nevertheless, lichen models are almost absent in fossil record of mimicry. Here, we provide the earliest fossil evidence of a mimetic relationship between the moth lacewing mimic Lichenipolystoechotes gen. nov. and its co-occurring fossil lichen model Daohugouthallus ciliiferus. We corroborate the lichen affinity of D. ciliiferus and document this mimetic relationship by providing structural similarities and detailed measurements of the mimic\u2019s wing and correspondingly the model\u2019s thallus. Our discovery of lichen mimesis predates modern lichen-insect associations by 165 million years, indicating that during the mid-Mesozoic, the lichen-insect mimesis system was well established and provided lacewings with highly honed survival strategies.", "keyphrases": ["lacewing", "fossil insect", "lichen mimesis"]}
{"id": "10.1111/j.1475-4983.2011.01117.x", "title": "A new genus of Devonian tetrapod from North\u2010East Greenland, with new information on the lower jaw of Ichthyostega", "abstract": "Abstract:\u2002 A new genus and species of Devonian tetrapod has been identified from material collected in 1947 from the southern slope of Mt. Celsius, Ymer \u00d8, North\u2010East Greenland. The specimen preserves both lower jaws, partial palate, premaxillae and maxillae, with a natural mould of parts of the shoulder girdle. The new taxon, Ymeria denticulata, shows differences in dentition, skull ornament and lateral line expression from both Acanthostega and Ichthyostega, but it shows a closer resemblance to the latter. A cladistic analysis not only suggests that Ymeria lies adjacent to Ichthyostega on the tetrapod stem, but also reveals substantial topological instability. As the third genus and the fifth species of tetrapod identified from North\u2010East Greenland, it demonstrates the high diversity of Devonian tetrapods in that region.", "keyphrases": ["new genus", "ichthyostega", "ymeria denticulata", "low jaw"]}
{"id": "paleo.004315", "title": "First Mesozoic Record of the Stingray Myliobatis wurnoensis from Mali and a Phylogenetic Analysis of Myliobatidae Incorporating Dental Characters", "abstract": "New specimens, including the first record of lower dental plates, of the extinct myliobatid Myliubatis wurnoensis were recovered from the Maastrichtian (Late Cretaceous) of the Iullemmeden Basin, Mali, and are the oldest record of the taxon. We evaluated the phylogenetic position of this taxon with reference to other myliobatids (extinct and extant) using osteology and dentition. Our results indicate that Myliobatinae and Myliobatis are each paraphyletic, and that Aetobatus and Rhinoptera are monophyletic. We also found that taxa known only from the Cretaceous, Brachyrhizodus and Igdabatis, are highly nested within Myliobatidae. The phylogenetic position of these taxa unambiguously extends the origin of Myliobatidae and most of its representative taxa into the Mesozoic.", "keyphrases": ["myliobatis", "mali", "myliobatidae", "dental plate", "maastrichtian"]}
{"id": "10.7717/peerj.7562", "title": "A new alligatoroid from the Eocene of Vietnam highlights an extinct Asian clade independent from extant Alligator sinensis", "abstract": "During systematic paleontological surveys in the Na Duong Basin in North Vietnam between 2009 and 2012, well-preserved fossilized cranial and postcranial remains belonging to at least 29 individuals of a middle to late Eocene (late Bartonian to Priabonian age (39\u201335 Ma)) alligatoroid were collected. Comparative anatomical study of the material warrants the diagnosis of a new taxon, Orientalosuchus naduongensis gen. et sp. nov. The combined presence of an enlarged fifth maxillary tooth, prominent preorbital ridges, a large supraoccipital exposure on the skull table, a palatine-pterygoid suture anterior to the posterior end of the suborbital fenestra, and a pterygoid forming a neck surrounding the choana is unique to this species. Unlike previous phylogenies, our parsimony analysis recovers a monophyletic Late Cretaceous to Paleogene East to Southeastern Asian alligatoroid group, here named Orientalosuchina. The group includes Orientalosuchus naduongensis, Krabisuchus siamogallicus, Eoalligator chunyii, Jiangxisuchus nankangensis and Protoalligator huiningensis, all of them sharing a medial shifted quadrate foramen aerum. The recognition of this clade indicates at least two separate dispersal events from North America to Asia: one during the Late Cretaceous by Orientalosuchina and one by the ancestor of Alligator sinensis during the Paleogene or Neogene, the timing of which is poorly constrained.", "keyphrases": ["alligatoroid", "eocene", "alligator sinensis"]}
{"id": "paleo.009378", "title": "Torvosaurus gurneyi n. sp., the Largest Terrestrial Predator from Europe, and a Proposed Terminology of the Maxilla Anatomy in Nonavian Theropods", "abstract": "The Lourinh\u00e3 Formation (Kimmeridgian-Tithonian) of Central West Portugal is well known for its diversified dinosaur fauna similar to that of the Morrison Formation of North America; both areas share dinosaur taxa including the top predator Torvosaurus, reported in Portugal. The material assigned to the Portuguese T. tanneri, consisting of a right maxilla and an incomplete caudal centrum, was briefly described in the literature and a thorough description of these bones is here given for the first time. A comparison with material referred to Torvosaurus tanneri allows us to highlight some important differences justifying the creation of a distinct Eastern species. Torvosaurus gurneyi n. sp. displays two autapomorphies among Megalosauroidea, a maxilla possessing fewer than eleven teeth and an interdental wall nearly coincidental with the lateral wall of the maxillary body. In addition, it differs from T. tanneri by a reduced number of maxillary teeth, the absence of interdental plates terminating ventrally by broad V-shaped points and falling short relative to the lateral maxillary wall, and the absence of a protuberant ridge on the anterior part of the medial shelf, posterior to the anteromedial process. T. gurneyi is the largest theropod from the Lourinh\u00e3 Formation of Portugal and the largest land predator discovered in Europe hitherto. This taxon supports the mechanism of vicariance that occurred in the Iberian Meseta during the Late Jurassic when the proto-Atlantic was already well formed. A fragment of maxilla from the Lourinh\u00e3 Formation referred to Torvosaurus sp. is ascribed to this new species, and several other bones, including a femur, a tibia and embryonic material all from the Kimmeridgian-Tithonian of Portugal, are tentatively assigned to T. gurneyi. A standard terminology and notation of the theropod maxilla is also proposed and a record of the Torvosaurus material from Portugal is given.", "keyphrases": ["terminology", "theropod", "torvosaurus material"]}
{"id": "10.1111/j.1502-3931.2010.00226.x", "title": "The Quilon Limestone, Kerala Basin, India: an archive for Miocene Indo-Pacific seagrass beds", "abstract": "The facies of the fossiliferous Quilon Limestone in SW India is described for the first time in detail at the Padappakkara-type locality. Facies (fossiliferous, micrite-rich, bioturbated sediment with intercalated sand pockets) and faunal composition (epiphytic foraminifers, seagrass feeding Smaragdia gastropods, bioimmuration of celleporiform bryozoan colonies) indicate a seagrass environment. The large discoidal archaiasin foraminifer Pseudotaberina malabarica, in particular, is considered as a proxy for seagrass communities. Recent seagrasses have their centre of generic richness in the Indo-Pacific where they cover wide areas in the tidal and shallow sub-tidal zones. However, their geological record is only fragmentary and their palaeobiogeographic distribution has a big stratigraphical gap in the Miocene Western Indo-Pacific region. The described nannoplankton flora and planktonic foraminifers from the Quilon Formation demonstrate that the deposition of the studied seagrass bed occurred in nannoplankton biozone NN3. This timing suggests formation during the closure of the Tethyan Seaway. The Quilon Limestone is thus an early Western Indo-Pacific seagrass bed and an important step in reconstructing the history of seagrass communities. h Quilon Formation, Pseudotaberina malabarica, seagrass facies, Burdigalian, Indo-Pacific.", "keyphrases": ["quilon limestone", "kerala basin", "seagrass environment"]}
{"id": "10.1080/00241160025100053", "title": "Experimental studies on microbial bioerosion at Lee Stocking Island, Bahamas and One Tree Island, Great Barrier Reef, Australia: implications for paleoecological reconstructions", "abstract": "Different kinds of experimental calcareous substrates were exposed at Lee Stocking Island (Bahamas) and One Tree Island (Great Barrier Reef, Australia) to study which endolithic bacteria, algae and fungi contribute to bioerosion and what their bioerosion rates are. The sites at Lee Stocking Island were several leeward shallow water and several windward shallow and deep-water positions (from the Acropora palmata reef at 2 m down to 275 m depth). At One Tree Island, the experiments were conducted in patch reefs treated with P and N to study the influence of mineral nutrients on bioerosion. The exposure periods ranged from 1 week to 2 years. The micritic carbonate substrates exposed on Lee Stocking Island contained 6 genera with 15 species of cyanobacteria, green and red algae, and different kinds of microendolithic heterotrophs. The mean values of bioerosion rates measured between 1 to 2 g/m 2 /y at 275 m and 520 g/m 2 /y at one of the leeward sites. The composition of the endolithic community and the bioerosion rates changed over time. At One Tree Island, shell pieces of Tridacna were used as substrate exposed for 5 months to endolith activity. Five genera and 6 species of cyanobacteria, green and red algae and different kinds of heterotrophic microendoliths were found with bioerosion rates of 20\u201330 g/m 2 /y. There are differences in abundance of taxa between Lee Stocking Island and One Tree Island. The introduction of nutrients had no apparent impact on the microborer community. Controlling factors for the distribution and abundance of microborers are mainly light, but also the kind of substrate and, possibly, the biogeographic position. The results support the paleoecological importance of microendoliths.", "keyphrases": ["bioerosion", "lee stocking island", "great barrier reef"]}
{"id": "paleo.005429", "title": "A New Saurolophine Dinosaur from the Latest Cretaceous of Far Eastern Russia", "abstract": "Background Four main dinosaur sites have been investigated in latest Cretaceous deposits from the Amur/Heilongjiang Region: Jiayin and Wulaga in China (Yuliangze Formation), Blagoveschensk and Kundur in Russia (Udurchukan Formation). More than 90% of the bones discovered in these localities belong to hollow-crested lambeosaurine saurolophids, but flat-headed saurolophines are also represented: Kerberosaurus manakini at Blagoveschensk and Wulagasaurus dongi at Wulaga. Methodology/Principal Findings Herein we describe a new saurolophine dinosaur, Kundurosaurus nagornyi gen. et sp. nov., from the Udurchukan Formation (Maastrichtian) of Kundur, represented by disarticulated cranial and postcranial material. This new taxon is diagnosed by four autapomorphies. Conclusions/Significance A phylogenetic analysis of saurolophines indicates that Kundurosaurus nagornyi is nested within a rather robust clade including Edmontosaurus spp., Saurolophus spp., and Prosaurolophus maximus, possibly as a sister-taxon for Kerberosaurus manakini also from the Udurchukan Formation of Far Eastern Russia. The high diversity and mosaic distribution of Maastrichtian hadrosaurid faunas in the Amur-Heilongjiang region are the result of a complex palaeogeographical history and imply that many independent hadrosaurid lineages dispersed without any problem between western America and eastern Asia at the end of the Cretaceous.", "keyphrases": ["new saurolophine dinosaur", "far eastern russia", "kerberosaurus manakini"]}
{"id": "10.1111/1475-4983.00330", "title": "Spinicaudatans and ostracods (Crustacea) from the Montceau Lagerst\u00e4tte (Late Carboniferous, France): morphology and palaeoenvironmental significance", "abstract": "Spinicaudatans and ostracods form two components of the diverse arthropod fauna from the Montceau Lagerst\u00e4tte (Stephanian, France). Spinicaudatans are represented by Montcestheria orri gen. and sp. nov. and Euestheria feysi sp. nov., and ostracods by a single species, Carbonita sp. aff. salteriana (Jones, 1862). Allied forms such as Montcestheria sp. aff. orri, Montcestheria sp. and Euestheria cebennensis (Grand'Eury, 1890), all from coeval localities in France, are also described. Montcestheria gen. nov. has carapace features, external (possibly sexual) dimorphism, preserved soft parts (e.g. appendages, gut) and resting eggs similar to those of Recent spinicaudatans, suggesting comparable lifestyles, reproductive strategies and feeding modes. Detailed anatomical comparisons are made with Cyzicus tetracerus from Recent ephemeral freshwater ponds. The ostracods belong to the Superfamily Carbonitoidea, which is a recurrent component of Carboniferous non\u2010marine biotas. Spinicaudatan\u2010rich assemblages typically occur in several Westphalian\u2013Stephanian Lagerst\u00e4tten (including Montceau) and localities from Europe and North America, where freshwater conditions prevailed, indicating that the group had already colonized continental waters by the Late Carboniferous. Similarities with the fauna from Recent temporary freshwater ponds (e.g. low diversity/high density spinicaudatan\u2010ostracod populations, synchronous spinicaudatan populations developing from resting eggs, high diversity/low density insects, amphibians) suggest the presence of temporary or ephemeral aquatic environments at Montceau as part of a complex limnic ecosystem. Flooding may have been the main driving force by which faunal and floral elements drifted away from their respective biotopes into the depositional areas, thus explaining the co\u2010occurrence of terrestrial (e.g.\u2003myriapods, scorpions, plants), amphibian and aquatic (e.g. conchostracans and syncarids from temporary and permanent settings, respectively) elements in fossil assemblages.", "keyphrases": ["ostracod", "montceau lagerst\u00e4tte", "late carboniferous"]}
{"id": "10.1111/1365-2745.12195", "title": "Looking forward through the past: identification of 50 priority research questions in palaeoecology", "abstract": "Priority question exercises are becoming an increasingly common tool to frame future agendas in conservation and ecological science. They are an effective way to identify research foci that advance the field and that also have high policy and conservation relevance. To date, there has been no coherent synthesis of key questions and priority research areas for palaeoecology, which combines biological, geochemical and molecular techniques in order to reconstruct past ecological and environmental systems on time\u2010scales from decades to millions of years. We adapted a well\u2010established methodology to identify 50 priority research questions in palaeoecology. Using a set of criteria designed to identify realistic and achievable research goals, we selected questions from a pool submitted by the international palaeoecology research community and relevant policy practitioners. The integration of online participation, both before and during the workshop, increased international engagement in question selection. The questions selected are structured around six themes: human\u2013environment interactions in the Anthropocene; biodiversity, conservation and novel ecosystems; biodiversity over long time\u2010scales; ecosystem processes and biogeochemical cycling; comparing, combining and synthesizing information from multiple records; and new developments in palaeoecology. Future opportunities in palaeoecology are related to improved incorporation of uncertainty into reconstructions, an enhanced understanding of ecological and evolutionary dynamics and processes and the continued application of long\u2010term data for better\u2010informed landscape management. Synthesis. Palaeoecology is a vibrant and thriving discipline, and these 50 priority questions highlight its potential for addressing both pure (e.g. ecological and evolutionary, methodological) and applied (e.g. environmental and conservation) issues related to ecological science and global change.", "keyphrases": ["priority research question", "palaeoecology", "dynamic"]}
{"id": "10.1111/brv.12203", "title": "\u2018Fish\u2019 (Actinopterygii and Elasmobranchii) diversification patterns through deep time", "abstract": "Actinopterygii (ray\u2010finned fishes) and Elasmobranchii (sharks, skates and rays) represent more than half of today's vertebrate taxic diversity (approximately 33000 species) and form the largest component of vertebrate diversity in extant aquatic ecosystems. Yet, patterns of \u2018fish\u2019 evolutionary history remain insufficiently understood and previous studies generally treated each group independently mainly because of their contrasting fossil record composition and corresponding sampling strategies. Because direct reading of palaeodiversity curves is affected by several biases affecting the fossil record, analytical approaches are needed to correct for these biases. In this review, we propose a comprehensive analysis based on comparison of large data sets related to competing phylogenies (including all Recent and fossil taxa) and the fossil record for both groups during the Mesozoic\u2013Cainozoic interval. This approach provides information on the \u2018fish\u2019 fossil record quality and on the corrected \u2018fish\u2019 deep\u2010time phylogenetic palaeodiversity signals, with special emphasis on diversification events. Because taxonomic information is preserved after analytical treatment, identified palaeodiversity events are considered both quantitatively and qualitatively and put within corresponding palaeoenvironmental and biological settings. Results indicate a better fossil record quality for elasmobranchs due to their microfossil\u2010like fossil distribution and their very low diversity in freshwater systems, whereas freshwater actinopterygians are diverse in this realm with lower preservation potential. Several important diversification events are identified at familial and generic levels for elasmobranchs, and marine and freshwater actinopterygians, namely in the Early\u2013Middle Jurassic (elasmobranchs), Late Jurassic (actinopterygians), Early Cretaceous (elasmobranchs, freshwater actinopterygians), Cenomanian (all groups) and the Paleocene\u2013Eocene interval (all groups), the latter two representing the two most exceptional radiations among vertebrates. For each of these events along with the Cretaceous\u2010Paleogene extinction, we provide an in\u2010depth review of the taxa involved and factors that may have influenced the diversity patterns observed. Among these, palaeotemperatures, sea\u2010levels, ocean circulation and productivity as well as continent fragmentation and environment heterogeneity (reef environments) are parameters that largely impacted on \u2018fish\u2019 evolutionary history, along with other biotic constraints.", "keyphrases": ["actinopterygii", "elasmobranchii", "diversification pattern", "vertebrate"]}
{"id": "10.1017/S1477201904001506", "title": "Pederpes finneyae, an articulated tetrapod from the tournaisian of Western Scotland", "abstract": "Synopsis The Tournaisian tetrapod Pederpes finneyae is described in detail, from the holotype and only specimen. The specimen derives from the Ballagan Formation, Tournaisian CM palynozone and is the earliest post\u2010Devonian tetrapod known from articulated remains. It is preserved almost complete except for the tail, some skull regions and a few limb extremities. The animal resembles Whatcheeria deltae from the Vis\u00e9an of Iowa, especially in the skull morphology, although the two differ in characters such as the lateral line expression, dermal ornament expression, proportions of the sub\u2010orbital portion of the jugal and several other dermal skull characters. The postcranial skeleton of Pederpes shows several unique features, including the structure of the leading edges of the cleithrum and clavicle, the form of the rib flanges and a possible supernumerary digit on the manus. The humerus is also unusual in possessing a spike\u2010like latissimus dorsi process, most like that of Baphetes. An investigation of the phylogenetic position of the whatcheeriids is carried out by comparing the results from two recently published databases. The clade lies very close to the base of the tetrapod stem group, although according to the dataset employed, the whatcheeriids compete with Crassigyrinus for the next most basal node after the Devonian forms. Possible whatcheeriids also occur in the Vis\u00e9an of Australia and the Tournaisian of Ireland and less certainly elsewhere, making the whatcheeriids a long\u2010lasting clade, widely distributed in time and space.", "keyphrases": ["tetrapod", "tournaisian", "pederpes finneyae"]}
{"id": "10.1098/rspb.2015.0136", "title": "Mountain uplift explains differences in Palaeogene patterns of mammalian evolution and extinction between North America and Europe", "abstract": "Patterns of late Palaeogene mammalian evolution appear to be very different between Eurasia and North America. Around the Eocene\u2013Oligocene (EO) transition global temperatures in the Northern Hemisphere plummet: following this, European mammal faunas undergo a profound extinction event (the Grande Coupure), while in North America they appear to pass through this temperature event unscathed. Here, we investigate the role of surface uplift to environmental change and mammalian evolution through the Palaeogene (66\u201323 Ma). Palaeogene regional surface uplift in North America caused large-scale reorganization of precipitation patterns, particularly in the continental interior, in accord with our combined stable isotope and ecometric data. Changes in mammalian faunas reflect that these were dry and high-elevation palaeoenvironments. The scenario of Middle to Late Eocene (50\u201337 Ma) surface uplift, together with decreasing precipitation in higher-altitude regions of western North America, explains the enigma of the apparent lack of the large-scale mammal faunal change around the EO transition that characterized western Europe. We suggest that North American mammalian faunas were already pre-adapted to cooler and drier conditions preceding the EO boundary, resulting from the effects of a protracted history of surface uplift.", "keyphrases": ["mammalian evolution", "north america", "europe"]}
{"id": "paleo.009593", "title": "Endocast morphology of Homo naledi from the Dinaledi Chamber, South Africa", "abstract": "Significance The new species Homo naledi was discovered in 2013 in a remote cave chamber of the Rising Star cave system, South Africa. This species survived until between 226,000 and 335,000 y ago, placing it in continental Africa at the same time as the early ancestors of modern humans were arising. Yet, H. naledi was strikingly primitive in many aspects of its anatomy, including the small size of its brain. Here, we have provided a description of endocast anatomy of this primitive species. Despite its small brain size, H. naledi shared some aspects of human brain organization, suggesting that innovations in brain structure were ancestral within the genus Homo. Hominin cranial remains from the Dinaledi Chamber, South Africa, represent multiple individuals of the species Homo naledi. This species exhibits a small endocranial volume comparable to Australopithecus, combined with several aspects of external cranial anatomy similar to larger-brained species of Homo such as Homo habilis and Homo erectus. Here, we describe the endocast anatomy of this recently discovered species. Despite the small size of the H. naledi endocasts, they share several aspects of structure in common with other species of Homo, not found in other hominins or great apes, notably in the organization of the inferior frontal and lateral orbital gyri. The presence of such structural innovations in a small-brained hominin may have relevance to behavioral evolution within the genus Homo.", "keyphrases": ["homo", "dinaledi chamber", "south africa"]}
{"id": "paleo.011517", "title": "A comprehensive diagnostic approach combining phylogenetic disease bracketing and CT imaging reveals osteomyelitis in a Tyrannosaurus rex", "abstract": "Traditional palaeontological techniques of disease characterisation are limited to the analysis of osseous fossils, requiring several lines of evidence to support diagnoses. This study presents a novel stepwise concept for comprehensive diagnosis of pathologies in fossils by computed tomography imaging for morphological assessment combined with likelihood estimation based on systematic phylogenetic disease bracketing. This approach was applied to characterise pathologies of the left fibula and fused caudal vertebrae of the non-avian dinosaur Tyrannosaurus rex. Initial morphological assessment narrowed the differential diagnosis to neoplasia or infection. Subsequent data review from phylogenetically closely related species at the clade level revealed neoplasia rates as low as 3.1% and 1.8%, while infectious-disease rates were 32.0% and 53.9% in extant dinosaurs (birds) and non-avian reptiles, respectively. Furthermore, the survey of literature revealed that within the phylogenetic disease bracket the oldest case of bone infection (osteomyelitis) was identified in the mandible of a 275-million-year-old captorhinid eureptile Labidosaurus. These findings demonstrate low probability of a neoplastic aetiology of the examined pathologies in the Tyrannosaurus rex and in turn, suggest that they correspond to multiple foci of osteomyelitis.", "keyphrases": ["phylogenetic disease bracketing", "osteomyelitis", "tyrannosaurus rex"]}
{"id": "10.1111/pala.12328", "title": "Integrating 2D and 3D shell morphology to disentangle the palaeobiology of ammonoids: a virtual approach", "abstract": "Based on data derived from computed tomography, we demonstrate that integrating 2D and 3D morphological data from ammonoid shells represents an important new approach for investigating the palaeobiology of ammonoids. Characterization of ammonite morphology has long been constrained to 2D data, with only a few studies collecting ontogenetic data in 180\u00b0 steps. Here we combine this traditional approach with 3D data collected from high\u2010resolution nano\u2010computed tomography. Ontogenetic morphological data on the hollow shell of a juvenile ammonite Kosmoceras (Jurassic, Callovian) was collected. 2D data was collected in 10\u00b0 steps and show significant changes in shell morphology. Preserved hollow spines show multiple mineralized membranes never reported before, representing temporal changes in the ammonoid mantle tissue. 3D data show that chamber volumes do not always increase exponentially, as was generally assumed, but may represent a proxy for life events, such as stress phases. Furthermore, chamber volume cannot be simply derived from septal spacing in forms comparable to Kosmoceras. Vogel numbers represent a 3D parameter for chamber shape, and those for Kosmoceras are similar to other ammonoids (Arnsbergites, Amauroceras) and modern cephalopods (Nautilus, Spirula). Two methods to virtually document the suture line ontogeny, used to document phylogenetic relationships of larger taxonomic entities, were applied for the first time and present a promising alternative to hand drawings. The curvature of the chamber surfaces increases during ontogeny due to increasing strength of ornamentation and septal complexity. As this may allow for faster handling of cameral liquid, it could compensate for decreasing SA/V ratios through ontogeny.", "keyphrases": ["shell morphology", "palaeobiology", "ammonoid", "kosmoceras"]}
{"id": "10.7717/peerj.1754", "title": "A large abelisaurid (Dinosauria, Theropoda) from Morocco and comments on the Cenomanian theropods from North Africa", "abstract": "We describe the partially preserved femur of a large-bodied theropod dinosaur from the Cenomanian \u201cKem Kem Compound Assemblage\u201d (KKCA) of Morocco. The fossil is housed in the Museo Geologico e Paleontologico \u201cGaetano Giorgio Gemmellaro\u201d in Palermo (Italy). The specimen is compared with the theropod fossil record from the KKCA and coeval assemblages from North Africa. The combination of a distally reclined head, a not prominent trochanteric shelf, distally placed lesser trochanter of stout, alariform shape, a stocky shaft with the fourth trochanter placed proximally, and rugose muscular insertion areas in the specimen distinguishes it from Carcharodontosaurus, Deltadromeus and Spinosaurus and supports referral to an abelisaurid. The estimated body size for the individual from which this femur was derived is comparable to Carnotaurus and Ekrixinatosaurus (up to 9 meters in length and 2 tons in body mass). This find confirms that abelisaurids had reached their largest body size in the \u201cmiddle Cretaceous,\u201d and that large abelisaurids coexisted with other giant theropods in Africa. We review the taxonomic status of the theropods from the Cenomanian of North Africa, and provisionally restrict the Linnean binomina Carcharodontosaurus iguidensis and Spinosaurus aegyptiacus to the type specimens. Based on comparisons among the theropod records from the Aptian-Cenomanian of South America and Africa, a partial explanation for the so-called \u201cStromer\u2019s riddle\u201d (namely, the coexistence of many large predatory dinosaurs in the \u201cmiddle Cretaceous\u201d record from North Africa) is offered in term of taphonomic artifacts among lineage records that were ecologically and environmentally non-overlapping. Although morphofunctional and stratigraphic evidence supports an ecological segregation between spinosaurids and the other lineages, the co-occurrence of abelisaurids and carcharodontosaurids, two groups showing several craniodental convergences that suggest direct resource competition, remains to be explained.", "keyphrases": ["abelisaurid", "theropod", "north africa"]}
{"id": "paleo.005453", "title": "Synchrotron-radiation computed tomography uncovers ecosystem functions of fly larvae in an Eocene forest", "abstract": "We report a hitherto unprecedented diversity of fly larvae (Diptera) from Eocene Baltic amber and the use of these to address palaeo-ecosystem functions and processes in the surrounding forests. Fly larvae have been considered exceptionally rare by the research community and have, like most insect larvae, been deemed of limited utility owing to challenges in identification. Herein, however, using synchrotron-x-ray radiation CT (SR-\u03bcCT) allowed us to detect and identify dozens of fly larvae from Baltic amber, and to infer their ecological interactions. One particular piece of amber contains 56 fly larvae and apparent mammalian feces. This fossil is of great interest for our understanding of carbon cycling in the Eocene forest. The occurrence of such a large number of fly larvae on the fecal remains indicates an important role of flies in recycling organic matter in the Eocene forest, much as some larvae do today. Analysis of the fly palaeo-communities also allowed us to hypothesize a mechanism by which massive, geologically relevant deposits of amber were formed in the Baltic region. Scanning allowed us to identify seven larvae closely related to the extant Syrphidae, whose larvae inhabit nests of eusocial Hymenoptera, or, sometimes, flows of sap dripping from trees damaged by other burrowing insect larvae. Viktor A. Baranov. Biology II, Ludwig-Maximilians-Universit\u00e4t M\u00fcnchen, Planegg, Bayern, Germany. Correspondence author. baranow@biologie.uni-muenchen.de Michael S. Engel. Natural Sciences and Mathematics Ecology & Evolutionary Biology, KU Biodiversity Institute, Kansas, USA. msengel@ku.edu J\u00f6rg Hammel. Institute of Materials Research, Helmholtz-Zentrum Geesthacht, Geesthacht, Germany. joerg.hammel@hzg.de Marie K. H\u00f6rnig. University of Greifswald, Zoological Institute and Museum,Cytology and Evolutionary Biology, Greifswald, Germany. marie.hoernig@palaeo-evo-devo.info Thomas van de Kamp. Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany and BARANOV ET AL.: DIPTERA LARVAE IN BALTIC AMBER 2 Laboratory for Applications of Synchrotron Radiation (LAS), Karlsruhe Institute of Technology (KIT), Kaiserstr. 1, 76131 Karlsruhe, Germany. thomas.vandekamp@kit.edu Marcus Zuber. Institute for Photon Science and Synchrotron Radiation (IPS), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany and Laboratory for Applications of Synchrotron Radiation (LAS), Karlsruhe Institute of Technology (KIT), Kaiserstr. 1, 76131 Karlsruhe, Germany. marcus.zuber@kit.edu Joachim T. Haug. Biology II, Ludwig-Maximilians-Universit\u00e4t M\u00fcnchen, Planegg, Bayern, Germany and Geobio-Center, Ludwig-Maximilians-Universit\u00e4t M\u00fcnchen, M\u00fcnchen, Bayern, Germany. jhaug@biologie.uni-muenchen.de", "keyphrases": ["fly", "eocene forest", "amber", "syrphidae", "wood-borer larvae"]}
{"id": "10.1006/jhev.2001.0535", "title": "Faunal change, environmental variability and late Pliocene hominin evolution.", "abstract": "Global change during the late Pliocene was manifested in declining temperatures, increased amplitude of climate cycles, and shifts in the periodicity of orbital climate forcing. Linking these changes to the evolution of African continental faunas and to hominin evolution requires well-documented fossil evidence that can be examined through substantial periods of time. The Omo sequence of southern Ethiopia provides such a database, and we use it to analyze change in the abundances of mammal taxa at different levels of temporal and taxonomic resolution between 4 and 2 Ma. This study provides new evidence for shifts through time in the ecological dominance of suids, cercopithecids, and bovids, and for a trend from more forested to more open woodland habitats. Superimposed on these long-term trends are two episodes of faunal change, one involving a marked shift in the abundances of different taxa at about 2.8+/-0.1 Ma, and the second the transition at 2.5 Ma from a 200-ka interval of faunal stability to marked variability over intervals of about 100 ka. The first appearance of Homo, the earliest artefacts, and the extinction of non-robust Australopithecus in the Omo sequence coincide in time with the beginning of this period of high variability. We conclude that climate change caused significant shifts in vegetation in the Omo paleo-ecosystem and is a plausible explanation for the gradual ecological change from forest to open woodland between 3.4 and 2.0 Ma, the faunal shift at 2.8 +/-0.1 Ma, and the change in the tempo of faunal variability of 2.5 Ma. Climate forcing in the late Pliocene is more clearly indicated by population shifts within the Omo mammal community than by marked turnover at the species level.", "keyphrases": ["variability", "bovid", "faunal change"]}
{"id": "10.1029/2003PA000950", "title": "Black shale deposition on the northwest African Shelf during the Cenomanian/Turonian oceanic anoxic event: Climate coupling and global organic carbon burial", "abstract": "High-resolution geochemical records from a depth transect through the Cenomanian/Turonian (C/T) Tarfaya Basin (northwest African Shelf) reveal high-amplitude fluctuations in accumulation rates of organic carbon (OC), redox-sensitive and sulphide-forming trace metals, and biomarkers indicative of photic zone euxinia. These fluctuations are in general coeval and thus imply a strong relationship of OC burial and water column redox conditions. The pacing and regularity of the records and the absence of a prominent continental signature suggest a dynamic depositional setting linked to orbital and higher-frequency forcing. Determining the dominant frequency depends on the definition of the most pronounced oceanic anoxic event (OAE2) and its duration. We propose that eccentricity is the main forcing factor at Tarfaya and controlled fluctuations in wind-driven upwelling of nutrient-rich, oxygen-depleted intermediate waters from the adjacent Atlantic and the periodic development of photic zone and bottom water euxinia on the mid-Cretaceous northwest African shelf. Accumulation records clearly identify the basin center as the primary site of sediment deposition with highest temporal variability and an up to six-fold increase in OC burial from similar to2 g/m(2) . yr prior to the OAE2 to similar to12 g/m(2) . yr during the OAE2. Photic zone and bottom water euxinia alternated with periods of greater oxygenation of the water column in response to climate forcing. Mass balance calculations imply that similar to2% of the overall global excess OC burial associated with the OAE2 was deposited in the Tarfaya Basin, an area that represented only similar to0.05% of the total global C/T ocean floor. In fact, the lateral extent of similar black shales along the African continental margin indicates that this part of the ocean contributed significantly to the global increase in organic carbon burial during the OAE2.", "keyphrases": ["northwest african shelf", "oceanic anoxic event", "organic carbon burial", "tarfaya basin"]}
{"id": "paleo.006238", "title": "Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared", "abstract": "The skull of a newly prepared Tarbosaurus bataar is described bone by bone and compared with a disarticulated skull of Tyrannosaurus rex. Both Tarbosaurus bataar and Tyrannosaurus rex skulls are deep in lateral view. In dorsal view, the skull of T. rex is extremely broad posteriorly but narrows towards the snout; in Ta. bataar the skull is narrower (especially in its ventral part: the premaxilla, maxilla, jugal, and the quadrate complex), and the expansion of the posterior half of the skull is less abrupt. The slender snout of Ta. bataar is reminiscent of more primitive North American tyrannosaurids. The most obvious difference between T. rex and Ta. bataar is the doming of the nasal in Ta. bataar which is high between the lacrimals and is less attached to the other bones of the skull, than in most tyrannosaurids. This is because of a shift in the handling of the crushing bite in Ta. bataar. We propose a paleogeographically based division of the Tyrannosaurinae into the Asiatic forms (Tarbosaurus and possibly Alioramus) and North American forms (Daspletosaurus and Tyrannosaurus). The division is supported by differences in anatomy of the two groups: in Asiatic forms the nasal is excluded from the major series of bones participating in deflecting the impact in the upper jaw and the dentary-angular interlocking makes a more rigid lower jaw.", "keyphrases": ["skull", "tarbosaurus bataar", "tyrannosaurus rex"]}
{"id": "10.1002/ecy.3864", "title": "Integrated evidence-based extent of occurrence for North American bison (Bison bison) since 1500 CE and before.", "abstract": "Following the near extinction of bison (Bison bison) from its historic range across North America in late 19th century, novel bison conservation efforts in the early 20th century catalyzed a popular widespread conservation movement to protect and restore bison among other species and places. Since Allen's initial delineation (1876) of the historic distribution of North American bison, subsequent attempts have been hampered by knowledge gaps about bison distribution and abundance previous to and following colonial arrival and settlement. For the first time, we apply a multi-disciplinary approach to assemble a comprehensive, integrated geographic database and meta-analysis of bison occurrences over the last 200,000\u2009years BCE, with particular emphasis over the last 450\u2009years before present. We combined paleontology, archaeology, and historical ecology data for our database totaling 6,438 observations. We derived the observations from existing online databases, published literature, and first-hand exploration journal entries. To illustrate the conservative maximum historical extent of occurrence of bison, we created a concave hull using observations occurring over the last 450\u2009years (n =\u20093,379 observations) which is the broadly accepted historical benchmark at 1500 CE covering 59% of the North American continent. While this distribution represents a historic extent of occurrence - merely delineating the maximum margins of the near-continental distribution - it does not replace a density-based approach reconstructing potential historical range distributions which identifies core and marginal ranges. However, we envision the contained observations of this database will contribute to further research in the increasingly evidence-based disciplines of bison ecology, evolution, rewilding, management, and conservation. There are no copyright or proprietary restrictions on this data, and this data paper should be cited when these data are reused.", "keyphrases": ["extent", "north american bison", "bison bison"]}
{"id": "paleo.008576", "title": "Digital Cranial Endocast of Hyopsodus (Mammalia, \u201cCondylarthra\u201d): A Case of Paleogene Terrestrial Echolocation?", "abstract": "We here describe the endocranial cast of the Eocene archaic ungulate Hyopsodus lepidus AMNH 143783 (Bridgerian, North America) reconstructed from X-ray computed microtomography data. This represents the first complete cranial endocast known for Hyopsodontinae. The Hyopsodus endocast is compared to other known \u201ccondylarthran\u201d endocasts, i. e. those of Pleuraspidotherium (Pleuraspidotheriidae), Arctocyon (Arctocyonidae), Meniscotherium (Meniscotheriidae), Phenacodus (Phenacodontidae), as well as to basal perissodactyls (Hyracotherium) and artiodactyls (Cebochoerus, Homacodon). Hyopsodus presents one of the highest encephalization quotients of archaic ungulates and shows an \u201cadvanced version\u201d of the basal ungulate brain pattern, with a mosaic of archaic characters such as large olfactory bulbs, weak ventral expansion of the neopallium, and absence of neopallium fissuration, as well as more specialized ones such as the relative reduction of the cerebellum compared to cerebrum or the enlargement of the inferior colliculus. As in other archaic ungulates, Hyopsodus midbrain exposure is important, but it exhibits a dorsally protruding largely developed inferior colliculus, a feature unique among \u201cCondylarthra\u201d. A potential correlation between the development of the inferior colliculus in Hyopsodus and the use of terrestrial echolocation as observed in extant tenrecs and shrews is discussed. The detailed analysis of the overall morphology of the postcranial skeleton of Hyopsodus indicates a nimble, fast moving animal that likely lived in burrows. This would be compatible with terrestrial echolocation used by the animal to investigate subterranean habitat and/or to minimize predation during nocturnal exploration of the environment.", "keyphrases": ["cranial endocast", "hyopsodus", "endocranial cast", "x-ray", "morphology"]}
{"id": "paleo.002127", "title": "A Computational Analysis of Limb and Body Dimensions in Tyrannosaurus rex with Implications for Locomotion, Ontogeny, and Growth", "abstract": "The large theropod dinosaur Tyrannosaurus rex underwent remarkable changes during its growth from <10 kg hatchlings to >6000 kg adults in <20 years. These changes raise fascinating questions about the morphological transformations involved, peak growth rates, and scaling of limb muscle sizes as well as the body's centre of mass that could have influenced ontogenetic changes of locomotion in T. rex. Here we address these questions using three-dimensionally scanned computer models of four large, well-preserved fossil specimens as well as a putative juvenile individual. Furthermore we quantify the variations of estimated body mass, centre of mass and segment dimensions, to characterize inaccuracies in our reconstructions. These inaccuracies include not only subjectivity but also incomplete preservation and inconsistent articulations of museum skeletons. Although those problems cause ambiguity, we conclude that adult T. rex had body masses around 6000\u20138000 kg, with the largest known specimen (\u201cSue\u201d) perhaps \u223c9500 kg. Our results show that during T. rex ontogeny, the torso became longer and heavier whereas the limbs became proportionately shorter and lighter. Our estimates of peak growth rates are about twice as rapid as previous ones but generally support previous methods, despite biases caused by the usage of scale models and equations that underestimate body masses. We tentatively infer that the hindlimb extensor muscles masses, including the large tail muscle M. caudofemoralis longus, may have decreased in their relative size as the centre of mass shifted craniodorsally during T. rex ontogeny. Such ontogenetic changes would have worsened any relative or absolute decline of maximal locomotor performance. Regardless, T. rex probably had hip and thigh muscles relatively larger than any extant animal's. Overall, the limb \u201cantigravity\u201d muscles may have been as large as or even larger than those of ratite birds, which themselves have the most muscular limbs of any living animal.", "keyphrases": ["tyrannosaurus rex", "locomotion", "muscle"]}
{"id": "paleo.005794", "title": "The evolution of tail weaponization in amniotes", "abstract": "Weaponry, for the purpose of intraspecific combat or predator defence, is one of the most widespread animal adaptations, yet the selective pressures and constraints governing its phenotypic diversity and skeletal regionalization are not well understood. Here, we investigate the evolution of tail weaponry in amniotes, a rare form of weaponry that nonetheless evolved independently among a broad spectrum of life including mammals, turtles and dinosaurs. Using phylogenetic comparative methods, we test for links between morphology, ecology and behaviour in extant amniotes known to use the tail as a weapon, and in extinct taxa bearing osseous tail armaments. We find robust ecological and morphological correlates of both tail lashing behaviour and bony tail weaponry, including large body size, body armour and herbivory, suggesting these life-history parameters factor into the evolution of antipredator behaviours and tail armaments. We suggest that the evolution of tail weaponry is rare because large, armoured herbivores are uncommon in extant terrestrial faunas, as they have been throughout evolutionary history.", "keyphrases": ["amniote", "weaponry", "rare form", "dinosaur tail club"]}
{"id": "paleo.010660", "title": "Cascading trend of Early Paleozoic marine radiations paused by Late Ordovician extinctions", "abstract": "Significance The first 120 million years of Phanerozoic life witnessed significant changes in biodiversity levels. Attempts to correlate these changes to potential short-term environmental drivers have been hampered by the crude temporal resolution of current biodiversity estimates. We present a biodiversity curve for the Early Paleozoic with high temporal precision. It shows that once equatorial sea-surface temperatures fell to present-day levels during the early Mid Ordovician, marine biodiversity accumulation accelerated dramatically. However, this acceleration ceased as increased volcanism commenced during the mid-Late Ordovician. Since biodiversity levels were not restored for at least \u223c35 million years, this finding redefines the nature of the end Ordovician mass extinctions and further reframes the Silurian as a prolonged recovery interval. The greatest relative changes in marine biodiversity accumulation occurred during the Early Paleozoic. The precision of temporal constraints on these changes is crude, hampering our understanding of their timing, duration, and links to causal mechanisms. We match fossil occurrence data to their lithostratigraphical ranges in the Paleobiology Database and correlate this inferred taxon range to a constructed set of biostratigraphically defined high-resolution time slices. In addition, we apply capture\u2013recapture modeling approaches to calculate a biodiversity curve that also considers taphonomy and sampling biases with four times better resolution of previous estimates. Our method reveals a stepwise biodiversity increase with distinct Cambrian and Ordovician radiation events that are clearly separated by a 50-million-year-long period of slow biodiversity accumulation. The Ordovician Radiation is confined to a 15-million-year phase after which the Late Ordovician extinctions lowered generic richness and further delayed a biodiversity rebound by at least 35 million years. Based on a first-differences approach on potential abiotic drivers controlling richness, we find an overall correlation with oxygen levels, with temperature also exhibiting a coordinated trend once equatorial sea surface temperatures fell to present-day levels during the Middle Ordovician Darriwilian Age. Contrary to the traditional view of the Late Ordovician extinctions, our study suggests a protracted crisis interval linked to intense volcanism during the middle Late Ordovician Katian Age. As richness levels did not return to prior levels during the Silurian\u2014a time of continental amalgamation\u2014we further argue that plate tectonics exerted an overarching control on biodiversity accumulation.", "keyphrases": ["early paleozoic", "mass extinction", "fossil occurrence data", "richness", "intense volcanism"]}
{"id": "paleo.003068", "title": "Understanding the ecology of host plant\u2013insect herbivore interactions in the fossil record through bipartite networks", "abstract": "Abstract. Plant\u2013insect associations have been a significant component of terrestrial ecology for more than 400 Myr. Exploring these interactions in the fossil record through novel perspectives provides a window into understanding evolutionary and ecological forces that shaped these interactions. For the past several decades, researchers have documented, described, and categorized fossil evidence of these interactions. Drawing on powerful tools from network science, we propose here a bipartite network representation of fossilized plants and their herbivore-induced leaf damage to understand late Paleozoic plant\u2013insect interactions at the local community level. We focus on four assemblages from north-central Texas, but the methods used in this work are general and can be applied to any well-preserved fossil flora. Network analysis can address key questions in the evolution of insect herbivory that often would be difficult to summarize using standard herbivory metrics.", "keyphrases": ["ecology", "network", "herbivory"]}
{"id": "10.1111/1365-2745.13565", "title": "What drives biodiversity patterns? Using long\u2010term multidisciplinary data to discern centennial\u2010scale change", "abstract": "Biodiversity plays an important role in ecosystem functioning, habitat recovery following disturbance and resilience to global environmental change. Long\u2010term ecological records can be used to explore biodiversity patterns and trends over centennial to multi\u2010millennial time\u2010scales across broad regions. Fossil pollen grains preserved in sediment over millennia reflect palynological richness and diversity, which relates to changes in landscape diversity. Other long\u2010term environmental data, such as fossil insects, palaeoclimate and archaeologically inferred palaeodemographic (population) data, hold potential to address questions about the drivers and consequences of diversity change when combined with fossil pollen records. This study tests a model of Holocene palynological diversity change through a synthesis of pollen and insect records from across the British Isles along with palaeodemographic trends and palaeoclimate records. We demonstrate relationships between human population change, insect faunal group turnover, palynological diversity and climate trends through the Holocene. Notable increases in population at the start of the British Neolithic (~6,000 calendar years before present [bp]) and Bronze Age (~4,200 bp) coincided with the loss of forests, increased agricultural activity and changes in insect faunal groups to species associated with human land use. Pollen diversity and evenness increased, most notably since the Bronze Age, as landscapes became more open and heterogeneous. However, regionally distinctive patterns are also evident within the context of these broad\u2010scale trends. Palynological diversity is correlated with population while diversity and population are correlated with some climate datasets during certain time periods (e.g. Greenland temperature in the mid\u2010late Holocene). Synthesis. This study has demonstrated that early human societies contributed to shaping palynological diversity patterns over millennia within the context of broader climatic influences upon vegetation. The connections between population and palynological diversity become increasingly significant in the later Holocene, implying intensifying impacts of human activity, which may override climatic effects. Patterns of palynological diversity trends are regionally variable and do not always follow expected trajectories. To fully understand the long\u2010term drivers of biodiversity change on regionally relevant ecological and management scales, future research needs to focus on amalgamating diverse data types, along with multi\u2010community efforts to harmonise data across broad regions.", "keyphrases": ["biodiversity pattern", "long\u2010term", "consequence"]}
{"id": "10.1098/rsta.2003.1240", "title": "Evidence for rapid climate change in the Mesozoic\u2013Palaeogene greenhouse world", "abstract": "The best\u2013documented example of rapid climate change that characterized the so\u2013called \u2018greenhouse world\u2019 took place at the time of the Palaeocene\u2013Eocene boundary: introduction of isotopically light carbon into the ocean\u2013atmosphere system, accompanied by global warming of 5\u20138 \u00b0C across a range of latitudes, took place over a few thousand years. Dissociation, release and oxidation of gas hydrates from continental\u2013margin sites and the consequent rapid global warming from the input of greenhouses gases are generally credited with causing the abrupt negative excursions in carbon\u2013 and oxygen\u2013isotope ratios. The isotopic anomalies, as recorded in foraminifera, propagated downwards from the shallowest levels of the ocean, implying that considerable quantities of methane survived upward transit through the water column to oxidize in the atmosphere. In the Mesozoic Era, a number of similar events have been recognized, of which those at the Triassic\u2013Jurassic boundary, in the early Toarcian (Jurassic) and in the early Aptian (Cretaceous) currently carry the best documentation for dramatic rises in temperature. In these three examples, and in other less well\u2013documented cases, the lack of a definitive time\u2013scale for the intervals in question hinders calculation of the rate of environmental change. However, comparison with the Palaeocene\u2013Eocene thermal maximum (PETM) suggests that these older examples could have been similarly rapid. In both the early Toarcian and early Aptian cases, the negative carbon\u2013isotope excursion precedes global excess carbon burial across a range of marine environments, a phenomenon that defines these intervals as oceanic anoxic events (OAEs). Osmium\u2013isotope ratios (187Os/188Os) for both the early Toarcian OAE and the PETM show an excursion to more radiogenic values, demonstrating an increase in weathering and erosion of continental crust consonant with elevated temperatures. The more highly buffered strontium\u2013isotope system (87Sr/86Sr) also shows relatively more radiogenic signatures during the early Toarcian OAE, but the early Aptian and Cenomanian\u2013Turonian OAEs show the reverse effect, implying that increased rates of sea\u2013floor spreading and hydrothermal activity dominated over continental weathering in governing sea\u2013water chemistry. The Cretaceous climatic optimum (late Cenomanian to mid Turonian) also shows evidence for abrupt cooling episodes characterized by episodic invasion of boreal faunas into temperate and subtropical regions and changes in terrestrial vegetation; drawdown of CO2 related to massive marine carbon burial (OAE) may be implicated here. The absence of a pronounced negative carbon\u2013isotope excursion preceding the Cenomanian\u2013Turonian OAE indicates that methane release is not necessarily connected to global deposition of marine organic carbon, but relative thermal maxima are common to all OAEs. \u2018Cold snaps\u2019 have also been identified from the Mesozoic record but their duration, causes and effects are poorly documented.", "keyphrases": ["rapid climate change", "rise", "greenhouse gas"]}
{"id": "10.1111/j.1365-2699.2006.01680.x", "title": "Reliability of pollen ratios for environmental reconstructions on the Tibetan Plateau", "abstract": "Aim\u2002 Pollen ratios are widely used to gain palaeovegetation and palaeoclimatic information from fossil pollen spectra, although their applicability has seldom been tested with modern pollen data. I used a data set of 113 lake\u2010surface sediments from the eastern Tibetan Plateau to test the reliability of several pollen ratios.", "keyphrases": ["pollen ratio", "tibetan plateau", "reliability"]}
{"id": "paleo.003781", "title": "ENVIRONMENTAL CONTROL OF DIVERSITY, EVOLUTIONARY RATES AND TAXA LONGEVITIES IN ANTARCTIC NEOGENE RADIOLARIA", "abstract": "Antarctic Neogene deep sea sediments preserve excellent species-level records of faunal evolution that can be compared to equivalent records of environmental change from stable isotopes of carbon and oxygen, and to changes in the planktonic biota as recorded by carbonate/biosilica values in the sediment. A synthesis of paleoenvironmental data and radiolarian occurrence data from three authors analyses of ODP Legs 119 and 120 to the Kerguelen Plateau shows an inverse correlation between overall radiolarian diversity and the inferred productivity of the environment. Higher diversity, spumellarian (presumed partly symbiont bearing) faunas are seen in lower productivity, earlier Neogene carbonate phytoplankton rich sediment, but give way to lower diversity, presumably deeper dwelling, nassellarian dominated faunas (mostly without symbionts) in the later Neogene, in synchrony with the development of higher productivity in the late Neogene Southern Ocean. Major turnover events and increases in average extinction rates are associated with the mid-Miocene (ca. 15-13 Ma) and end-Miocene (ca. 7-4 Ma) increased glaciation and increased productivity shifts on or around Antarctica. Species longevities also decrease substantially during the Neogene, a phenomenon not previously reported for Cenozoic microfossils. In older sediments a bimodal distribution of taxon longevities is observed, although this latter phenomenon may be an artifact of the data analysis. Although environmental change appears to be the primary determinant of evolutionary change in these faunas, biologically mediated secondary effects caused by change in the physical environment (e.g., productivity and nutrient availability), are inferred to be the proximal causes driving evolution.", "keyphrases": ["evolutionary rate", "antarctic neogene", "environmental control"]}
{"id": "paleo.002799", "title": "A Morphometric Approach to the Specific Separation of the Humeri and Femora of Dicraeosaurus from the Late Jurassic of Tendaguru,Tanzania", "abstract": "The two species of dicraeosaurid dinosaurs Dicraeosaurus, Dicraeosaurus hansemanni, and Dicraeosaurus sattleri, have been distinguished mainly by their differences in size and geological age, as they occur in different members of the Late Jurassic Tendaguru Formation of Tanzania. Linear and geometric morphometric measurements distinguish between the humeri and femora of both species. Linear measurements and Principal Component Analysis of Thin-plate Splines reveal strong differences in size and shape between their humeri and weak differences between their femora, also supported by a Discriminant Factor Analysis. Generally, the humerus and femur of D. hansemanni are slightly longer and more robust than those of D. sattleri. Further, the humerus is shorter in relation to the femur in D. sattleri, related to its more distally positioned deltopectoral crest, resulting in differences in its arc of movement and mechanical power. Thus, a morphological separation between the humeri and femora of D. hansemanni from the Middle Dinosaur Member and D. sattleri from the Upper Dinosaur Member of the Tendaguru Formation can be confirmed. Morphometric comparisons of the humeri and femora of Dicraeosaurus with the single known humerus and femur of Amargasaurus cazaui reveal many shape differences between the two genera, which are especially well marked in the Thin-plate Splines analysis and affect in particular the humerus. These results suggest a closer relationship between D. hansemanni and D. sattleri than between D. sattleri and A. cazaui, and a clear separation between the two genera.", "keyphrases": ["humeri", "femora", "dicraeosaurus"]}
{"id": "paleo.002010", "title": "ROLE OF CONSTRAINT AND SELECTION IN THE MORPHOLOGIC EVOLUTION OF CARYOCORBULA (MOLLUSCA: CORBULIDAE) FROM THE CARIBBEAN NEOGENE", "abstract": "We examined patterns of morphologic evolution in Caryocorbula, a common bivalve genus of the Caribbean Neogene, to evaluate the roles that constraint and selection play in its apparent morphologic conservatism. With multivariate analyses using landmark-based geometric morphometrics, we examined the relationship of valve size and outline shape within the Caryocorbula + (Bothrocorbula + Hexacorbula) clade, and within 21 morphospecies of Caryocorbula, all from Neogene deposits of the Caribbean region. We found that each genus is morphologically distinct both in shape and size, and that Caryocorbula shows strong interspecific allometry that persists despite species turnover and the vagaries of geographic and temporal sample coverage.\nPersistence of this allometric trend indicates that constraints shape Caryocorbula morphology. Constraint mechanisms may relate to 1) space limitations in the inequivalved shells that characterize Corbulidae, and/or 2) the need for functional articulation of unequal valves through a complex shell accretion history. Alternatively, environmental conditions, particularly nutrient availability, may control the spatial and temporal distribution of large Caryocorbula, but constraint via pleiotropy could restrict the shape of these bivalves. Finally, although constraints appear to play an important role in the morphologic evolution of Neogene Caryocorbula, an adaptive relationship of size and shape to environment is not precluded, as illustrated for Caryocorbula species from the late Miocene-early Pliocene of the northern Dominican Republic. The morphology of these species falls along the interspecific allometric curve, but each is also characteristic of a particular paleoenvironmental setting, with valve size and shape tracking with inferred depth and physical energy gradients.", "keyphrases": ["morphologic evolution", "corbulidae", "caribbean neogene", "bivalve"]}
{"id": "paleo.003815", "title": "No mass extinction for land plants at the Permian\u2013Triassic transition", "abstract": "The most severe mass extinction among animals took place in the latest Permian (ca. 252 million years ago). Due to scarce and impoverished fossil floras from the earliest Triassic, the common perception has been that land plants likewise suffered a mass extinction, but doubts remained. Here we use global occurrence data of both plant macro- and microfossils to analyse plant biodiversity development across the Permian\u2013Triassic boundary. We show that the plant fossil record is strongly biased and that evidence for a mass extinction among plants in the latest Permian is not robust. The taxonomic diversities of gymnosperm macrofossils and of the pollen produced by this group are particularly incongruent. Our results indicate that gymnosperm macrofossils are considerably undersampled for the Early Triassic, which creates the impression of increased gymnosperm extinction in the latest Permian.", "keyphrases": ["mass extinction", "land plant", "taxonomic diversity"]}
{"id": "10.1130/G23666A.1", "title": "Large-scale hydrological change drove the late Miocene C4 plant expansion in the Himalayan foreland and Arabian Peninsula", "abstract": "Carbon isotope changes in paleosols from Siwalik, Pakistan, and marine sediments from the Bengal Fan indicate a major C 4 plant expansion in the Himalayan foreland during the late Miocene. However, the timing and mechanisms behind the C 4 plant expansion remain enigmatic. Here we present high-resolution (\u223c60 k.y.) biomarker and compound-specific isotope data spanning the past 11 m.y. from Ocean Drilling Program Site 722 in the Arabian Sea. An \u223c5\u2030\u20136\u2030 increase in leaf wax \u03b4 13 C values indicates a marked rise of C 4 plants from 10 to 5.5 Ma, with accelerated expansion from 7.9 to 5.5 Ma. A concurrent \u223c50\u2030 rise in leaf wax \u03b4D values is attributed to a combined effect of changes in precipitation amount and evaporation, indicating that source regions for the plant waxes became progressively drier from 10 to 5.5 Ma. In contrast to earlier reports, our isotope records, biomarker abundances, alkenone U K\u2032 37 , and Globigerina bulloides abundance data do not suggest enhanced summer monsoon circulation during this time interval. Rather, our results suggest that large-scale hydrological changes drove the late Miocene expansion of C 4 plants in the Himalayan foreland and Arabian Peninsula.", "keyphrases": ["miocene", "foreland", "arabian peninsula", "large-scale hydrological change"]}
{"id": "paleo.006396", "title": "Reductions in body size of benthic macroinvertebrates as a precursor of the early Toarcian (Early Jurassic) extinction event in the Lusitanian Basin, Portugal", "abstract": "Reduction of body size is a common response of organisms to environmental stress. Studying the early Toarcian succession in the Lusitanian Basin of Portugal, we tested whether the shell size of benthic marine communities of bivalves and brachiopods changed at and before the global, warming-related Toarcian oceanic anoxic event (T-OAE). Statistical analyses of shell size over time show that the mean shell size of communities decreased significantly before the T-OAE. This trend is distinct in brachiopods and is caused by larger-sized species becoming less abundant over time, whereas it is not significant in bivalves, suggesting a decoupled response to environmental stress. Reductions in shell size precede the decline in standardized sample-level species richness associated with the early Toarcian extinction event. Such decreases in the shell size of marine invertebrates, well before the onset of biodiversity change, suggest that reductions in body size more generally may be a precursor of a subsequent loss of species and turnover at the community level caused by climate change. Sedimentological evidence is against hypoxia as a driver of extinction and the preceding size decrease in the brachiopod fauna in the studied succession, although low oxygen levels are widely held responsible for elevated early Toarcian extinction rates globally. Reduction of mean shell size in brachiopods but stasis in bivalves is difficult to explain with ocean acidification, because experimental work shows that brachiopods can be resilient to lowered pH, albeit long-term metabolic costs and potential evolutionary adaptations are unknown. Rising early Toarcian temperatures in the Lusitanian Basin seem to be a plausible factor in both diversity decline associated with the T-OAE and the preceding reductions in mean shell size, because thermal tolerances in modern bivalves are among the highest within marine invertebrates.", "keyphrases": ["body size", "extinction event", "lusitanian basin"]}
{"id": "10.1080/00222939800771101", "title": "Fossil stomatopods (Crustacea: Malacostraca) and their phylogenetic impact", "abstract": "The Stomatopoda form a distinctive order within the Malacostraca. It is an ancient group of benthic, obligate carnivorous crustaceans. Various studies have focused on stomatopods, mainly in regard to their taxonomy, their complex behaviour patterns, and the advanced neurophysiology of their visual systems. The \u03b1-taxonomy of this group seems well established; their phylogeny, however, still remains unclear. Palaeontological information can contribute significantly to the resolution of this group's phylogeny. Fossil evidence has already indicated that the ancestors of stomatopods probably diverged from other malacostracans in the Devonian. The first true stomatopods appear in the Carboniferous. The Mesozoic stomatopod families Sculdidae and Pseudosculdidae were studied more than a century ago. These early investigations on fossil stomatopods are of excellent quality. Unfortunately these sources were underestimated in later work on fossil stomatopods. The Cenozoic fossil stomatopod record appears to be riche...", "keyphrases": ["malacostraca", "pseudosculdidae", "fossil stomatopod"]}
{"id": "10.1080/10420940.2012.664056", "title": "New Sauropod Tracks (Brontopodus pentadactylus ichnosp. nov.) from the Early Cretaceous Haman Formation of Jinju Area, Korea: Implications for Sauropods Manus Morphology", "abstract": "New sauropod tracks are described herein as Brontopodus pentadactylus ichnosp. nov. from the Early Cretaceous Haman Formation of Jinju area, Korea. B. pentadactylus is characterized by a medium gauged trackway with wide pentadactyl manus tracks revealing hitherto unreported morphology. Thus, B. pentadactylus provides new insight into the morphology of the fleshed-out manus of sauropods showing that, unlike most semi-circular manus tracks that lack discrete digit traces, some indicate trackmakers with clearly differentiated, well-defined, and very wide manus digits. Manus tracks sometimes appear as tridactyl impressions that appear outwardly rotated at right angles to the midline of the trackway. This track morphology appears to reflect greater weight distribution on the outer, postero-lateral part of the manus. The pes is elongate, pentadactyl, outwardly rotated, and typical of Brontopodus. The manus pes heteropody ratio is about 1:2. These sauropod tracks are associated with thousands of bird footprints in a lakeshore paleoenvironment.", "keyphrases": ["brontopodus pentadactylus ichnosp", "haman formation", "jinju area"]}
{"id": "10.1080/03115518.2016.1164402", "title": "New damselflies (Odonata: Zygoptera: Hemiphlebiidae, Dysagrionidae) from mid-Cretaceous Burmese amber", "abstract": "Zheng, D., Zhang, Q., Nel, A., Jarzembowski, E.A., Zhou, Z., Chang, S.-C. & Wang, B., May 2016. New damselflies (Odonata: Zygoptera: Hemiphlebiidae, Dysagrionidae) from mid-Cretaceous Burmese amber. Alcheringa XX, xxx\u2013xxx. ISSN 0311-5518 Two damselflies, Burmahemiphlebia zhangi gen. et sp. nov. and Palaeodysagrion cretacicus gen. et sp. nov., are described from the mid-Cretaceous Burmese amber. Burmahemiphlebia zhangi is the first record of Hemiphlebiidae from this amber, although the family was cosmopolitan during the Mesozoic. It can be readily distinguished from all other members of Hemiphlebiidae in having very short MP and CuA veins, and in its rectangular discoidal cell. The new fossils support the view that hemiphlebiid damselflies were one of the dominant groups of Zygoptera during the Mesozoic. Palaeodysagrion cretacicus is the first dysagrionid damselfly from Burmese amber and the second Mesozoic representative of this predominantly Paleogene group. It differs from other members of Dysagrionidae in having a unique elongate discoidal cell. These new finds increase the diversity of damselflies in mid-Cretaceous Burmese amber. Daran Zheng* [dranzheng@gmail.com], Su-Chin Chang [suchin@hku.hk], Department of Earth Sciences, The University of Hong Kong, Hong Kong Special Administrative Region, PR China; Qingqing Zhang [qqzhang@nigpas.ac.cn], Edmund A. Jarzembowski\u2020 [edj@nigpas.ac.cn], Bo Wang\u2021 [bowang@nigpas.ac.cn], State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, PR China; Andr\u00e9 Nel [anel@mnhn.fr], Institut de Syst\u00e9matique, \u00c9volution, Biodiversit\u00e9, ISYEB-UMR 7205-CNRS, MNHN, UPMC, EPHE, Mus\u00e9um national d\u2019Histoire naturelle, Sorbonne Universit\u00e9s, 57 rue Cuvier, CP 50, Entomologie, F-75005, Paris, France; Zhicheng Zhou [172692308@qq.com], The PLA Information Engineering University, 62 Kexue Ave, Gaoxin District, Zhengzhou 450002, Henan, PR China. *Also affiliated with State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, 39 East Beijing Road, Nanjing 210008, PR China. \u2020Also affiliated with Department of Earth Sciences, The Natural History Museum, London SW7 5BD, UK. \u2021Also affiliated with Key Laboratory of Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, PR China.", "keyphrases": ["damselfly", "zygoptera", "hemiphlebiidae"]}
{"id": "paleo.010434", "title": "Ostrich eggshell bead diameter in the Holocene: Regional variation with the spread of herding in eastern and southern Africa", "abstract": "Despite their ubiquity in Holocene African archaeological assemblages, ostrich eggshell (OES) beads are rarely studied in detail. An exception is in southern Africa, where there is a proposed relationship between OES bead diameter and the arrival of herding ~2000 years before present. In 1987, Leon Jacobson first observed that beads from forager sites in Namibia tended to be smaller than those associated with herder sites. Studies examining bead size around the Western Cape have generally confirmed Jacobson\u2019s findings, though the driving forces of the diameter change remain unknown. Since this time, diameter has become an informal way of distinguishing forager and herder assemblages in southern Africa, but no large-scale studies of OES bead variation have been undertaken. Here we present an expanded analysis of Holocene OES bead diameters from southern, and for the first time, eastern Africa. Results reveal distinct patterns in OES bead size over time, reflecting different local dynamics associated with the spread of herding. In southern Africa, OES diameters display low variability and smaller absolute size through time. While larger beads begin to appear <2000 years ago, most beads in our study remained smaller. In contrast, eastern African OES bead diameters are consistently larger over the last 10,000 years and show no appreciable size change with the introduction of herding. Notably, larger beads thought to be associated with herders in southern Africa fall within the range of eastern African beads, indicating a potential connection between these regions in the Late Holocene consistent with genetic findings. Regional differences in bead size are subtle, on the order of millimeters, yet offer a potentially important line of evidence for investigating the spread of herding in sub-Saharan Africa. In order to understand the meaning of these changes, we encourage additional studies of OES bead assemblages and urge researchers to report individual bead diameters, rather than averages by level.", "keyphrases": ["diameter", "holocene", "oes bead assemblage", "ostrich eggshell"]}
{"id": "paleo.003119", "title": "Mammalian tooth marks on the bones of dinosaurs and other Late Cretaceous vertebrates", "abstract": "Abstract:\u2002 We describe bones from the Late Cretaceous of Alberta \u2013 including bones of large dinosaurs, a femur from the aquatic reptile Champsosaurus, and a dentary from the marsupial Eodelphis\u2013 that bear tooth marks made by animals with opposing pairs of teeth. Of the animals known from the Late Cretaceous of North America, only mammals are capable of making such tooth marks. In particular, multituberculates, which have paired upper and lower incisors, are the most likely candidates for the makers of these traces. The traces described here represent the oldest known mammalian tooth marks. Although it is possible that some of these tooth marks represent feeding traces, the tooth marks often penetrate deep into the dense cortices of the bone. This raises the possibility that, much as extant mammals gnaw bone and antler, some Cretaceous mammals may have consumed the bones of dinosaurs and other vertebrates as a source of minerals. However, none of the tooth marks described here resemble the extensive gnaw traces produced by Cenozoic multituberculates or rodents. This suggests that specialized gnawing forms may have been rare or absent in the Late Cretaceous of North America.", "keyphrases": ["vertebrate", "feeding trace", "mammalian tooth mark"]}
{"id": "paleo.001121", "title": "Red Devonian trilobites with green eyes from Morocco and the silicification of the trilobite exoskeleton", "abstract": "Latest Emsian (Early Devonian) sediments at the famous mud-mound-and trilobite-locality Hamar Laghdad (Tafilalt, Morocco) yielded some red-coloured remains of phacopid trilobites. Closer examination revealed that the eyes of these phacopids are often greenish in colour. EDX-analyses showed that the lenses retained their original calcitic composition, possibly greenish due to Fe-and Mn-impurities, while most of the exoskeleton was silicified. The silicified parts contain elevated concentrations of iron which causes the red colour. This phenomenon is explained by the porosity of the exoskeleton in contrast to the homogeneous and massive construction of the lenses and their Mg-content. These incompletely silicified trilobites enabled a reconstruction of the silicification process in trilobites. Their diagenetic alteration probably occurred as a result of events associated with the Cretaceous transgression.", "keyphrases": ["devonian", "eye", "exoskeleton"]}
{"id": "paleo.005174", "title": "Killing in the Pliocene: shark attack on a dolphin from Italy", "abstract": "Abstract:\u2002 Shark bite marks, including striae, sulci and abrasions, in a well\u2010preserved fossil dolphin skeleton referred to Astadelphis gastaldii (Cetacea, Delphinidae) from Pliocene sediments of Piedmont (northern Italy), are described in detail. The exceptional combination of a fossil dolphin having a significant part of the skeleton preserved and a large number of bite marks on the bones represents one of the few detailed documentations of shark attack in the past. Most bite marks have been referred to a shark about 4\u2003m long with unserrated teeth, belonging to Cosmopolitodus hastalis, on the basis of their shape and their general disposition on the dolphin skeleton. According to our hypothesis, the shark attacked the dolphin with an initial mortal bite to the abdomen from the rear and right, in a similar way as observed for the living white shark when attacking pinnipeds. A second, less strong, bite was given on the dorsal area when the dolphin, mortally injured, probably rolled to the left. The shark probably released the prey, dead or dying, and other sharks or fishes probably scavenged the torn body of the dolphin.", "keyphrases": ["shark attack", "dolphin", "italy", "cetacean bone"]}
{"id": "10.1017/S0016756800010451", "title": "Carbon- and oxygen-isotope stratigraphy of the English Chalk and Italian Scaglia and its palaeoclimatic significance", "abstract": "Abstract A detailed carbon- and oxygen-isotope stratigraphy has been generated from Upper Cretaceous coastal Chalk sections in southern England (East Kent; Culver Cliff, Isle of Wight; Eastbourne and Seaford Head, Sussex; Norfolk Coast) and the British Geological Survey (BGS) Trunch borehole, Norfolk. Data are also presented from a section through the Scaglia facies exposed near Gubbio, Italian Apennines. Wherever possible the sampling interval has been one metre or less. Both the Chalk and Scaglia carbon-isotopic curves show minor positive excursions in the mid-Cenomanian, mid- and high Turonian, basal Coniacian and highest Santonian\u2013lowest Campanian; there is a negative excursion high in the Campanian in Chalk sections that span that interval. The well-documented Cenomanian\u2013Turonian boundary \u2018spike\u2019 is also well displayed, as is a broad positive excursion centred on the upper Coniacian. A number of these positive excursions correlate with records of organic-carbon-rich deposition in the Atlantic Ocean and elsewhere. The remarkable similarity in the carbon-isotope curves from England and Italy enables cross-referencing of macrofossil and microfossil zones and pinpoints considerable discrepancy in the relative positions of the Turonian, Coniacian and Santonian stages. The oxygen-isotope values of the various Chalk sections, although showing different absolute values that are presumably diagenesis-dependent, show nonetheless a consistent trend. The East Kent section, which is very poorly lithified, indicates a warming up to the Cenomanian\u2013Turonian boundary interval, then cooling thereafter. Regional organic-carbon burial, documented for this period, is credited with causing drawdown of CO2 and initiating climatic deterioration (inverse greenhouse effect). Data from other parts of the world are consistent with the hypothesis that the Cenomanian\u2013Turonian temperature optimum was a global phenomenon and that this interval represents a major turning point in the climatic history of the earth.", "keyphrases": ["oxygen-isotope stratigraphy", "turonian", "carbon-"]}
{"id": "10.1098/rstb.2015.0510", "title": "Biogeochemical significance of pelagic ecosystem function: an end-Cretaceous case study", "abstract": "Pelagic ecosystem function is integral to global biogeochemical cycling, and plays a major role in modulating atmospheric CO2 concentrations (pCO2). Uncertainty as to the effects of human activities on marine ecosystem function hinders projection of future atmospheric pCO2. To this end, events in the geological past can provide informative case studies in the response of ecosystem function to environmental and ecological changes. Around the Cretaceous\u2013Palaeogene (K\u2013Pg) boundary, two such events occurred: Deccan large igneous province (LIP) eruptions and massive bolide impact at the Yucatan Peninsula. Both perturbed the environment, but only the impact coincided with marine mass extinction. As such, we use these events to directly contrast the response of marine biogeochemical cycling to environmental perturbation with and without changes in global species richness. We measure this biogeochemical response using records of deep-sea carbonate preservation. We find that Late Cretaceous Deccan volcanism prompted transient deep-sea carbonate dissolution of a larger magnitude and timescale than predicted by geochemical models. Even so, the effect of volcanism on carbonate preservation was slight compared with bolide impact. Empirical records and geochemical models support a pronounced increase in carbonate saturation state for more than 500 000 years following the mass extinction of pelagic carbonate producers at the K\u2013Pg boundary. These examples highlight the importance of pelagic ecosystems in moderating climate and ocean chemistry.", "keyphrases": ["pelagic ecosystem function", "case study", "volcanism"]}
{"id": "paleo.002599", "title": "Early vertebrate evolution", "abstract": "Debate over the origin and evolution of vertebrates has occupied biologists and palaeontologists alike for centuries. This debate has been refined by molecular phylogenetics, which has resolved the place of vertebrates among their invertebrate chordate relatives, and that of chordates among their deuterostome relatives. The origin of vertebrates is characterized by wide\u2010ranging genomic, embryologic and phenotypic evolutionary change. Analyses based on living lineages suggest dramatic shifts in the tempo of evolutionary change at the origin of vertebrates and gnathostomes, coincident with whole\u2010genome duplication events. However, the enriched perspective provided by the fossil record demonstrates that these apparent bursts of anatomical evolution and taxic richness are an artefact of the extinction of phylogenetic intermediates whose fossil remains evidence the gradual assembly of crown gnathostome characters in particular. A more refined understanding of the timing, tempo and mode of early vertebrate evolution rests with: (1) better genome assemblies for living cyclostomes; (2) a better understanding of the anatomical characteristics of key fossil groups, especially the anaspids, thelodonts, galeaspids and pituriaspids; (3) tests of the monophyly of traditional groups; and (4) the application of divergence time methods that integrate not just molecular data from living species, but also morphological data and extinct species. The resulting framework will provide for rigorous tests of rates of character evolution and diversification, and of hypotheses of long\u2010term trends in ecological evolution that themselves suffer for lack of quantitative functional tests. The fossil record has been silent on the nature of the transition from jawless vertebrates to the jawed vertebrates that have dominated communities since the middle Palaeozoic. Elucidation of this most formative of episodes likely rests with the overhaul of early vertebrate systematics that we propose, but perhaps more fundamentally with fossil grades that await discovery.", "keyphrases": ["cyclostome", "anaspid", "early vertebrate evolution"]}
{"id": "paleo.012872", "title": "Palaeoecology and palaeophytogeography of the Rhynie chert plants: further evidence from integrated analysis of in situ and dispersed spores", "abstract": "The remarkably preserved Rhynie chert plants remain pivotal to our understanding of early land plants. The extraordinary anatomical detail they preserve is a consequence of exceptional preservation, by silicification, in the hot-springs environment they inhabited. However, this has prompted questions as to just how typical of early land plants the Rhynie chert plants really are. Some have suggested that they were highly adapted to the unusual hot-springs environment and are unrepresentative of \u2018normal\u2019 plants of the regional flora. New quantitative analysis of dispersed spore assemblages from the stratigraphical sequence of the Rhynie outlier, coupled with characterization of the in situ spores of the Rhynie chert plants, permits investigation of their palaeoecology and palaeophytogeography. It is shown that the Rhynie inland intermontane basin harboured a relatively diverse flora with only a small proportion of these plants actually inhabiting the hot-springs environment. However, the flora of the Rhynie basin differed from coeval lowland floodplain deposits on the same continent, as it was less diverse, lacked some important spore groups and contained some unique elements. At least some of the Rhynie plants (e.g. Horneophyton lignieri) existed outside the hot-springs environment, inhabiting the wider basin, and were indeed palaeogeographically widespread. They probably existed in the hot-springs environment because they were preadapted to this unstable and harsh setting. This article is part of a discussion meeting issue \u2018The Rhynie cherts: our earliest terrestrial ecosystem revisited\u2019.", "keyphrases": ["palaeophytogeography", "situ", "spore assemblage"]}
{"id": "paleo.001615", "title": "Testing models of dental development in the earliest bony vertebrates, Andreolepis and Lophosteus", "abstract": "Theories on the development and evolution of teeth have long been biased by the fallacy that chondrichthyans reflect the ancestral condition for jawed vertebrates. However, correctly resolving the nature of the primitive vertebrate dentition is challenged by a dearth of evidence on dental development in primitive osteichthyans. Jaw elements from the Silurian\u2013Devonian stem-osteichthyans Lophosteus and Andreolepis have been described to bear a dentition arranged in longitudinal rows and vertical files, reminiscent of a pattern of successional development. We tested this inference, using synchrotron radiation X-ray tomographic microscopy (SRXTM) to reveal the pattern of skeletal development preserved in the sclerochronology of the mineralized tissues. The tooth-like tubercles represent focal elaborations of dentine within otherwise continuous sheets of the dermal skeleton, present in at least three stacked generations. Thus, the tubercles are not discrete modular teeth and their arrangement into rows and files is a feature of the dermal ornamentation that does not reflect a polarity of development or linear succession. These fossil remains have no bearing on the nature of the dentition in osteichthyans and, indeed, our results raise questions concerning the homologies of these bones and the phylogenetic classification of Andreolepis and Lophosteus.", "keyphrases": ["dental development", "andreolepis", "lophosteus", "tooth"]}
{"id": "10.1017/pab.2017.38", "title": "Spinosity, regeneration, and targeting among Paleozoic crinoids and their predators", "abstract": "Abstract. \n Evolving interactions between predators and prey constitute one of the major adaptive influences on marine animals during the Paleozoic. Crinoids and fish constitute a predator\u2014prey system that may date back to at least the Silurian, as suggested by patterns of crinoid regeneration and spinosity in concert with changes in the predatory fauna. Here we present data on the frequency of breakage and regeneration in the spines of the Middle Devonian camerate Gennaeocrinus and late Paleozoic cladids, as well as an expanded survey of the prevalence of spinosity and infestation by platyceratid gastropods on crinoid genera during the Paleozoic. Spine regeneration frequency in the measured populations is comparable to arm regeneration frequencies from Mississippian Rhodocrinites and from modern deepwater crinoid populations. The prevalence of spinosity varies by taxon, time, and anatomy among Paleozoic crinoids; notably, spinosity in camerates increased from the Silurian through the Mississippian and decreased sharply during the Pennsylvanian, whereas spines were uncommon in cladids until their Late Mississippian diversification. Among camerates, tegmen spinosity is positively correlated with the presence of infesting platyceratid gastropods. These results allow us to evaluate several hypotheses for the effects of predation on morphological differences between early, middle, and late Paleozoic crinoid faunas. Our data corroborate the hypothesis that predators targeted epibionts on camerate crinoids and anal sacs on advanced cladids and suggest that the replacement of shearing predators by crushing predators after the Hangenberg extinction affected the locations of spines in Mississippian camerates.", "keyphrases": ["paleozoic crinoid", "predator", "camerate crinoid", "spinosity"]}
{"id": "10.1144/SP306.3", "title": "Present-day stresses, seismicity and Neogene-to-Recent tectonics of Australia's \u2018passive\u2019 margins: intraplate deformation controlled by plate boundary forces", "abstract": "Abstract Neogene-to-Recent deformation is widespread on and adjacent to Australia's \u2018passive\u2019 margins. Elevated historical seismic activity and relatively high levels of Neogene-to-Recent tectonic activity are recognized in the Flinders and Mount Lofty Ranges, the SE Australian Passive Margin, SW Western Australia and the North West Shelf. In all cases the orientation of palaeostresses inferred from Neogene-to-Recent structures is consistent with independent determinations of the orientation of the present-day stress field. Present-day stress orientations (and neotectonic palaeostress trends) vary across the Australian continent. Plate-scale stress modelling that incorporates the complex nature of the convergent plate boundary of the Indo-Australian Plate (with segments of continent\u2013continent collision, continent\u2013arc collision and subduction) indicates that present-day stress orientations in the Australian continent are consistent with a first-order control by plate-boundary forces. The consistency between the present-day, plate-boundary-sourced stress orientations and the record of deformation deduced from neotectonic structures implicates plate boundary forces in the ongoing intraplate deformation of the Australian continent. Deformation rates inferred from seismicity and neotectonics (as high as 10\u221216 s\u22121) are faster than seismic strain rates in many other \u2018stable\u2019 intraplate regions, suggestive of unusually high stress levels imposed on the Australian intraplate environment from plate boundary interactions many thousands of kilometres distant. The spatial overlap of neotectonic structures and zones of concentrated historical seismicity with ancient fault zones and/or regions of enhanced crustal heat flow indicates that patterns of active deformation in Australia are in part, governed, by prior tectonic structuring and are also related to structural and thermal weakening of continental crust. Neogene-to-Recent intraplate deformation within the Australian continent has had profound and under-recognized effects on hydrocarbon occurrence, both by amplifying some hydrocarbon-hosting structures and by inducing leakage from pre-existing traps due to fault reactivation or tilting.", "keyphrases": ["seismicity", "intraplate deformation", "boundary force"]}
{"id": "10.1111/pala.12451", "title": "A quantitative method for inferring locomotory shifts in amniotes during ontogeny, its application to dinosaurs and its bearing on the evolution of posture", "abstract": "Evolutionary transitions between quadrupedal and bipedal postures are pivotal to the diversification of amniotes on land, including in our own lineage (Hominini). Heterochrony is suggested as a macroevolutionary mechanism for postural transitions but understanding postural evolution in deep time is hindered by a lack of methods for inferring posture in extinct species. Dinosaurs are an excellent natural laboratory for understanding postural transitions because they demonstrate at least four instances of quadrupedality evolving from bipedality, and heterochronic processes have been put forward as an explanatory model for these transitions. We extend a quantitative method for reliably inferring posture in tetrapods to the study of ontogenetic postural transitions using measurements of proportional limb robusticity. We apply this to ontogenetic series of living and extinct amniotes, focusing on dinosaurs. Our method correctly predicts the general pattern of ontogenetic conservation of quadrupedal and bipedal postures in many living amniote species and infers the same pattern in some dinosaurs. Furthermore, it correctly predicts the ontogenetic postural shift from quadrupedal crawling to bipedal walking in humans. We also infer a transition from early ontogenetic quadrupedality to late\u2010ontogenetic bipedality in the transitional sauropodomorph dinosaur Mussaurus patagonicus and possibly in the early branching ceratopsian Psittacosaurus lujiatunensis but not in the sauropodomorph Massospondylus carinatus. The phylogenetic positions of these ontogenetic shifts suggest that heterochrony may play a role in the macroevolution of posture, at least in dinosaurs. Our method has substantial potential for testing evolutionary transitions between locomotor modes, especially in elucidating the role of evolutionary mechanisms like heterochrony.", "keyphrases": ["quantitative method", "amniote", "posture", "ontogenetic shift"]}
{"id": "paleo.011723", "title": "The timescale of early land plant evolution", "abstract": "Significance Establishing the timescale of early land plant evolution is essential to testing hypotheses on the coevolution of land plants and Earth\u2019s System. Here, we establish a timescale for early land plant evolution that integrates over competing hypotheses on bryophyte\u2212tracheophyte relationships. We estimate land plants to have emerged in a middle Cambrian\u2013Early Ordovocian interval, and vascular plants to have emerged in the Late Ordovician\u2212Silurian. This timescale implies an early establishment of terrestrial ecosystems by land plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land plants, or attempt to explain their impact, must consider a much earlier, middle Cambrian\u2013Early Ordovician, origin. Establishing the timescale of early land plant evolution is essential for testing hypotheses on the coevolution of land plants and Earth\u2019s System. The sparseness of early land plant megafossils and stratigraphic controls on their distribution make the fossil record an unreliable guide, leaving only the molecular clock. However, the application of molecular clock methodology is challenged by the current impasse in attempts to resolve the evolutionary relationships among the living bryophytes and tracheophytes. Here, we establish a timescale for early land plant evolution that integrates over topological uncertainty by exploring the impact of competing hypotheses on bryophyte\u2212tracheophyte relationships, among other variables, on divergence time estimation. We codify 37 fossil calibrations for Viridiplantae following best practice. We apply these calibrations in a Bayesian relaxed molecular clock analysis of a phylogenomic dataset encompassing the diversity of Embryophyta and their relatives within Viridiplantae. Topology and dataset sizes have little impact on age estimates, with greater differences among alternative clock models and calibration strategies. For all analyses, a Cambrian origin of Embryophyta is recovered with highest probability. The estimated ages for crown tracheophytes range from Late Ordovician to late Silurian. This timescale implies an early establishment of terrestrial ecosystems by land plants that is in close accord with recent estimates for the origin of terrestrial animal lineages. Biogeochemical models that are constrained by the fossil record of early land plants, or attempt to explain their impact, must consider the implications of a much earlier, middle Cambrian\u2013Early Ordovician, origin.", "keyphrases": ["timescale", "land plant evolution", "ordovician", "fossil calibration", "calibration"]}
{"id": "10.1093/sysbio/syaa069", "title": "A Total-Evidence Dated Phylogeny of Echinoidea Combining Phylogenomic and Paleontological Data.", "abstract": "Phylogenomic and paleontological data constitute complementary resources for unravelling the phylogenetic relationships and divergence times of lineages, yet few studies have attempted to fully integrate them. Several unique properties of echinoids (sea urchins) make them especially useful for such synthetizing approaches, including a remarkable fossil record that can be incorporated into explicit phylogenetic hypotheses. We revisit the phylogeny of crown group Echinoidea using a total-evidence dating approach that combines the largest phylogenomic dataset for the clade, a large-scale morphological matrix with a dense fossil sampling, and a novel compendium of tip and node age constraints. To this end, we develop a novel method for subsampling phylogenomic datasets that selects loci with high phylogenetic signal, low systematic biases and enhanced clock-like behavior. Our results demonstrate that combining different data sources increases topological accuracy and helps resolve conflicts between molecular and morphological data. Notably, we present a new hypothesis for the origin of sand dollars, and restructure the relationships between stem and crown echinoids in a way that implies a long stretch of undiscovered evolutionary history of the crown group in the late Paleozoic. Our efforts help bridge the gap between phylogenomics and phylogenetic paleontology, providing a model example of the benefits of combining the two.", "keyphrases": ["total-evidence", "phylogeny", "paleontological data", "sea urchin"]}
{"id": "10.1080/02724634.2015.1040118", "title": "Persiatherium rodleri, gen. et sp. nov. (Mammalia, Rhinocerotidae) from the Upper Miocene of Maragheh (Northwestern Iran)", "abstract": "ABSTRACT \n A new genus and species of Rhinocerotidae, Persiatherium rodleri, gen. et sp. nov., a new acerathere rhinocerotid from the early upper Miocene (ca. 9 Ma) locality of Kopran, Maragheh (northwestern Iran), is described. The new taxon can be clearly distinguished from the three species previously reported at Maragheh: Iranotherium morgani, Ceratotherium neumayri, and Chilotherium persiae. Moreover, P. rodleri can be distinguished from the latest middle and late Miocene elasmotheres, teleoceratins, and rhinoceroses recorded in Eurasia and Africa. The new taxon displays morphological characters close to Aceratheriini. However, the presence of plesiomorphic characters on the teeth (presence of P1, continuous lingual cingula on the premolars, labial cingula on the premolars, lingual cingula on the molars, weak protocone constriction on the molars, absence of crista and antecrochet on the molars), of peculiar morphological characters (e.g., lingual side of the protoloph and metaloph directed disto-lingually on P2 with the presence of a lingual groove on the hypocone), as well as some derived characters (e.g., short metaloph on the molars), enable its distinction from other Aceratheriini. A cladistic analysis shows that P. rodleri is the sister taxon to \u2018Aceratherium huadeensis'. Though the latter displays more derived features than P. rodleri, their phylogenetic relationships allow inclusion of both species in the same new genus.", "keyphrases": ["rhinocerotidae", "upper miocene", "persiatherium rodleri"]}
{"id": "10.1080/10420940390256212", "title": "Preliminary Report on the Courtedoux Dinosaur Tracksite from the Kimmeridgian of Switzerland", "abstract": "In 2002 a new dinosaur tracksite was discovered in calcareous laminites of early Late Kimmeridgian age along the future course of the \u201cTransjurane\u201d highway in Courtedoux, Canton Jura, Northern Switzerland. The site has an extraordinary scientific potential, as the laminites, which have been deposited in an intertidal to supratidal environment, contain at least 6 track-bearing levels in a total thickness of about 1 m. The laminites are being systematically excavated by the \u201cSection de paleontologie\u201d over an area of approximately 1500 m2. So far the main track level has been uncovered over an area of about 650 m2, which reveals 2 trackways of theropods and 17 trackways of sauropods. The sauropod tracks are the smallest known in the Kimmeridgian so far, and the trackways belong to the ichnogenus Parabrontopodus, which has been revealed for the first time in Switzerland. The tracksite belongs to the \u201cMiddle Kimmeridgian megatracksite\u201d sensu Meyer (2000), and represents the most important dinosaur tracksite in Switzerland, perhaps with the potential for development into one of the world's largest sauropod tracksites. It will be protected in situ underneath an especially constructed highway-bridge, thus offering opportunities for future research and the development of an interpretative center for education and tourism.", "keyphrases": ["dinosaur tracksite", "kimmeridgian", "switzerland"]}
{"id": "10.1525/auk.2012.11227", "title": "A Marabou (Ciconiidae: Leptoptilos) from the Middle Pleistocene of Northeastern China", "abstract": "ABSTRACT. \n A new species of marabou, Leptoptilos l\u00fci sp. nov., is described on the basis of a cranium, distal humerus, and proximal phalanx of the major digit, from the Middle Pleistocene Jinniushan locality, Liaoning Province of northeastern China. Fossil crania of the genus Leptoptilos are rare, and that of the new bird is distinct from the crania of its extant relatives. The forelimb elements are the largest and most robust among living and fossil species of Leptoptilos and are characterized by autapomorphic characters. Leptoptilos l\u00fci, like the African Marabou Stork (L. crumeniferus), probably possessed a considerable flight capability and fed mainly on pieces of carrion torn from carcasses by other, sympatric large scavengers. The new stork aids in our understanding of the paleoecology and paleoenvironment of northeastern China in the Middle Pleistocene, helps us characterize the scavenger guild that fed on the Middle Pleistocene megafauna, and shows that the genus Leptoptilos, now restricted to the Old World tropics, extended into higher latitudes in the Middle Pleistocene.", "keyphrases": ["leptoptilos", "middle pleistocene", "northeastern china"]}
{"id": "10.1111/boj.12357", "title": "Is post-polyploidization diploidization the key to the evolutionary success of angiosperms?", "abstract": "Advances in recent years have revolutionized our understanding of both the context and occurrence of polyploidy in plants. Molecular phylogenetics has vastly improved our understanding of plant relationships, enabling us to better understand trait and character evolution, including chromosome number changes. This, in turn, has allowed us to appreciate better the frequent occurrence and extent of polyploidy throughout the history of angiosperms, despite the occurrence of low chromosome numbers in some groups, such as in Arabidopsis (A.\u2009thaliana was the first plant genome to be sequenced and assembled). In tandem with an enhanced appreciation of phylogenetic relationships, the accumulation of genomic data has led to the conclusion that all angiosperms are palaeopolyploids, together with better estimates of the frequency and type of polyploidy in different angiosperm lineages. The focus therefore becomes when a lineage last underwent polyploidization, rather than simply whether a plant is \u2018diploid\u2019 or \u2018polyploid\u2019. This legacy of past polyploidization in plants is masked by large-scale genome reorganization involving repetitive DNA loss, chromosome rearrangements (including fusions and fissions) and complex patterns of gene loss, a set of processes that are collectively termed \u2018diploidization\u2019. We argue here that it is the diploidization process that is responsible for the \u2018lag phase\u2019 between polyploidization events and lineage diversification. If so, diploidization is important in determining chromosome structure and gene content, and has therefore made a significant contribution to the evolutionary success of flowering plants. \u00a9 2015 The Authors. Botanical Journal of the Linnean Society published by John Wiley & Sons Ltd on behalf of The Linnean Society of London, Botanical Journal of the Linnean Society, 2015, \u25cf\u25cf, \u25cf\u25cf\u2013\u25cf\u25cf.", "keyphrases": ["diploidization", "evolutionary success", "angiosperm"]}
{"id": "paleo.008043", "title": "The Upper Cretaceous belemnite Praeactinocamax plenus (Blainville, 1827) from Lower Saxony (Upper Cenomanian, northwest Germany) and its distribution pattern in Europe", "abstract": "Occurrences of the Upper Cenomanian (Upper Cretaceous) belemnite Praeactinocamax plenus from the plenus Bed of northwest Germany (So \u00a8hlde-Loges working quarry near Salzgitter, Lower Saxony) are documented and described for the first time on the basis of two in situ finds. The find horizon and its surrounding beds are re-evaluated in a sequence stratigraphical context. In contrast to the interpretations of other authors, the plenus Bed is seen as a pelagization event in a parasequence of transgressively stacked beds, delimited by two significant erosion surfaces below and above. The exclusive occurrence of P. plenus in the top part of the plenus Bed and its absence from the post-plenus Bed succession, in the equivalent of which (higher part of the Plenus Marls Member) it is very common in southern England (Anglo-Paris Basin), is explained by ecological factors in stratigraphically complete sections (intra-shelf depressions) and by gaps in the stratigraphic records in swell settings. The distribution pattern of P. plenus suggests a preference for nearshore settings and a demersal mode of life.", "keyphrases": ["belemnite praeactinocamax plenu", "lower saxony", "upper cenomanian"]}
{"id": "10.1130/G48696.1", "title": "Maturation experiments reveal bias in the chemistry of fossil melanosomes", "abstract": "Fossil melanosomes are a major focus of paleobiological research because they can inform on the original coloration, phylogenetic affinities, and internal anatomy of ancient animals. Recent studies of vertebrate melanosomes revealed tissue-specific trends in melanosome-metal associations that can persist in fossils. In some fossil vertebrates, however, melanosomes from all body regions are enriched only in Cu, suggesting diagenetic overprinting of original chemistry. We tested this hypothesis using laboratory experiments on melanosomes from skin and liver of the African clawed frog Xenopus laevis. After maturation in Cu-rich media, the metal chemistry of melanosomes from these tissues converged toward a common composition, and original differences in Cu oxidation state were lost. Elevated Cu concentrations and a pervasive Cu(II) signal are likely indicators of diagenetically altered melanosomes. These results provide a robust experimental basis for interpretating the chemistry of fossil melanosomes.", "keyphrases": ["chemistry", "fossil melanosome", "signal"]}
{"id": "10.1017/pab.2019.33", "title": "Aragonite bias exhibits systematic spatial variation in the Late Cretaceous Western Interior Seaway, North America", "abstract": "Abstract. Preferential dissolution of the biogenic carbonate polymorph aragonite promotes preservational bias in shelly marine faunas. While field studies have documented the impact of preferential aragonite dissolution on fossil molluscan diversity, its impact on regional and global biodiversity metrics is debated. Epicontinental seas are especially prone to conditions that both promote and inhibit preferential dissolution, which may result in spatially extensive zones with variable preservation. Here we present a multifaceted evaluation of aragonite dissolution within the Late Cretaceous Western Interior Seaway of North America. Occurrence data of mollusks from two time intervals (Cenomanian/Turonian boundary, early Campanian) are plotted on new high-resolution paleogeographies to assess aragonite preservation within the seaway. Fossil occurrences, diversity estimates, and sampling probabilities for calcitic and aragonitic fauna were compared in zones defined by depth and distance from the seaway margins. Apparent range sizes, which could be influenced by differential preservation potential of aragonite between separate localities, were also compared. Our results are consistent with exacerbated aragonite dissolution within specific depth zones for both time slices, with aragonitic bivalves additionally showing a statistically significant decrease in range size compared with calcitic fauna within carbonate-dominated Cenomanian\u2013Turonian strata. However, we are unable to conclusively show that aragonite dissolution impacted diversity estimates. Therefore, while aragonite dissolution is likely to have affected the preservation of fauna in specific localities, time averaging and instantaneous preservation events preserve regional biodiversity. Our results suggest that the spatial expression of taphonomic biases should be an important consideration for paleontologists working on paleobiogeographic problems.", "keyphrases": ["western interior seaway", "north america", "dissolution"]}
{"id": "paleo.007756", "title": "A new basal sauropod from the pre-Toarcian Jurassic of South Africa: evidence of niche-partitioning at the sauropodomorph\u2013sauropod boundary?", "abstract": "The early evolution of sauropod dinosaurs remains poorly understood, with a paucity of unequivocal sauropod taxa known from the first twenty million years of the Jurassic. Recently, the Early Jurassic of South Africa has yielded an assemblage of dental and post-cranial remains displaying a more apomorphic character suite than any other similarly aged sauropodomorph. These remains are interpreted as a new species of basal sauropod and recovered cladistically as the sister taxon to Vulcanodon +more derived Sauropoda, underscoring its importance for our understanding of this pivotal period of sauropod evolution. Key changes in the dentition, axial skeleton and forelimb of this new species suggest a genuine functional distinction occurring at the sauropodiform-sauropod boundary. With reference to these changes, we propose a scenario in which interdependent refinements of the locomotory and feeding apparatus occurred in tandem with, or were effected by, restrictions in the amount of vertical forage initially available to the earliest sauropods. The hypothesized instance of niche-partitioning between basal sauropodan taxa and higher-browsing non-sauropodan sauropodomorphs may partially explain the rarity of true sauropods in the basal rocks of the Jurassic, while having the added corollary of couching the origins of Sauropoda in terms of an ecologically delimited \u2018event\u2019.", "keyphrases": ["basal sauropod", "jurassic", "early evolution"]}
{"id": "paleo.002089", "title": "A new docodont mammal from the Late Jurassic of the Junggar Basin in Northwest China", "abstract": "Fieldwork in the early Late Jurassic (Oxfordian) Qigu Formation of the Junggar Basin in Northwest China (Xinjiang Autonomous Region) produced teeth and mandibular fragments of a new docodont. The new taxon has a large \"pseudotalonid\" on the lower molars, and by retention of crest b-g exhibits closer affinities to Simpsonodon and Krusatodon from the Middle Jurassic of Europe than to the other known Asian docodonts Tashkumyrodon, Tegotherium, and Sibirotherium. It differs from the Haldanodon-Docodon-lineage by the \"pseudotalonid\" and large cusps b and g. A PAUP analysis based on lower molar characters produced a single most parsimonious tree with two main clades. One clade comprises Docodon, Haldanodon, and Borealestes, and the other Dsungarodon, Simpsonodon, and Krusatodon plus the Asian tegotheriids. Analysis of the molar occlusal relationships using epoxy casts mounted on a micromanipulator revealed a four-phase chewing cycle with transverse component. The molars of the new docodont exhibit a well developed grinding function besides cutting and shearing, probably indicating an omnivorous or even herbivorous diet. A grinding and crushing function is also present in the molars of Simpsonodon, Krusatodon, and the Asian tegotheriids, whereas Borealestes, Haldanodon, and Docodon retain the plesiomorphic molar pattern with mainly piercing and cutting function.", "keyphrases": ["junggar basin", "crocodilian", "isolated dinosaur tooth", "turtle"]}
{"id": "10.1130/B25275.1", "title": "The Geology of the Darien, Panama, and the late Miocene-Pliocene collision of the Panama arc with northwestern South America", "abstract": "The geology of the Darien province of eastern Panama is presented through a new geologic map and detailed biostratigraphic and paleobathymetric analysis of its Upper Cretaceous to upper Miocene sediments. The sequence of events inferred from the stratigraphic record includes the collision of the Panama arc (the southwestern margin of the Caribbean plate) and South American continent. Three tectonostratigraphic units underlie the Darien region: (1) Precollisional Upper Cretaceous\u2013Eocene crystalline basement rocks of the San Blas Complex form a series of structurally complex topographic massifs along the northeastern and southwestern margins of the Darien province. These rocks formed part of a >20 m.y. submarine volcanic arc developed in a Pacific setting distant from the continental margin of northwestern South America. The northerly basement rocks are quartz diorites, granodiorites, and basaltic andesites, through dacites to rhyolites, indicating the presence of a magmatic arc. The southerly basement rocks are an accreted suite of diabase, pillow basalt, and radiolarian chert deposited at abyssal depths. Precollisional arc-related rocks, of Eocene to lower Miocene age, consist of 4000 m of pillow basalts and volcaniclastics, and biogenic calcareous and siliceous deep-water sediments. They consist of the Eocene-Oligocene Darien Formation, the Oligocene Porcona Formation and the lower-middle Miocene Clarita Formation. Postcollisional deposits are mostly coarse- to fine-grained siliciclastic sedimentary rocks and turbiditic sandstone of upper middle to latest Miocene age. This 3000 m thick sedimentary sequence is deformed as part of a complexly folded and faulted synclinorium that forms the central Chucunaque-Tuira Basin of the Darien. The sedimentary package reveals general shallowing of the basin from bathyal to inner neritic depths during the 12.8\u22127.1 Ma collision of the Panama arc with South America. The sediments are divided into the upper middle Miocene Tapaliza Formation, the lower upper Miocene Tuira and Membrillo Formations, the middle upper Miocene Yaviza Formation, and the middle to upper Miocene Chucunaque Formation.\n\nThe precollisional open marine units of Late Cretaceous\u2013middle Miocene age are separated from the overlying postcollisional sequence of middle to late Miocene age by a regional unconformity at 14.8\u221212.8 Ma. This unconformity marks the disappearance of radiolarians, the changeover of predominantly silica deposition from the Atlantic to the Pacific, the initiation of the uplift of the isthmus of Panama, and the onset of shallowing upward, coarser clastic deposition. This pattern is also recorded from the southern Limon Basin of Caribbean Costa Rica to the Atrato Basin of northwestern Colombia. By the middle late Miocene, neritic depths were widespread throughout the Darien region, and a regional unconformity suggests completion of the Central American arc collision with South America by 7.1 Ma. No Pliocene deposits are recorded from either the Darien or the Panama Canal Basin, and no sediments younger than 4.8 Ma have been identified in the Atrato Basin of Colombia, suggesting rapid uplift and extensive emergence of the Central American isthmus in the latest Miocene.\n\nNorthward movement of the eastern segment of the Panama arc along a now quiescent Panama Canal Zone fault during Eocene-Oligocene time may have dislocated the pre-collision arc. Since collision, the portion west of this fault (Chorotega Block) has remained stable, without rotation; to the east, in the Darien region, compression has been accommodated through formation of a Panama microplate with convergent boundaries to the north (North Panama deformed belt) and south (South Panama deformed belt), and suturing with South America along the Atrato Valley. Deformation within the microplate has been accommodated in the Darien province by several major left-lateral strike-slip faults that were active until the early Pliocene, since when the plate has behaved rigidly.", "keyphrases": ["geology", "northwestern south america", "late miocene"]}
{"id": "paleo.005516", "title": "The predatory behaviour of the thylacine: Tasmanian tiger or marsupial wolf?", "abstract": "The extinct thylacine (Thylacinus cynocephalus) and the extant grey wolf (Canis lupus) are textbook examples of convergence between marsupials and placentals. Craniodental studies confirm the thylacine's carnivorous diet, but little attention has been paid to its postcranial skeleton, which would confirm or refute rare eyewitness reports of a more ambushing predatory mode than the pack-hunting pursuit mode of wolves and other large canids. Here we show that thylacines had the elbow morphology typical of an ambush predator, and propose that the \u2018Tasmanian tiger\u2019 vernacular name might be more apt than the \u2018marsupial wolf\u2019. The \u2018niche overlap hypothesis\u2019 with dingoes (Canis lupus dingo) as a main cause of thylacine extinction in mainland Australia is discussed in the light of this new information.", "keyphrases": ["thylacine", "tiger", "marsupial wolf"]}
{"id": "paleo.001108", "title": "Cougars\u2019 key to survival through the Late Pleistocene extinction: insights from dental microwear texture analysis", "abstract": "Cougars (Puma concolor) are one of only two large cats in North America to have survived the Late Pleistocene extinction (LPE), yet the specific key(s) to their relative success remains unknown. Here, we compare the dental microwear textures of Pleistocene cougars with sympatric felids from the La Brea Tar Pits in southern California that went extinct at the LPE (Panthera atrox and Smilodon fatalis), to clarify potential dietary factors that led to the cougar's persistence through the LPE. We further assess whether the physical properties of food consumed have changed over time when compared with modern cougars in southern California. Using dental microwear texture analysis (DMTA), which quantifies surface features in three dimensions, we find that modern and Pleistocene cougars are not significantly different from modern African lions in any DMTA attributes, suggesting moderate durophagy (i.e. bone processing). Pleistocene cougars from La Brea have significantly greater complexity and textural fill volume than Panthera atrox (inferred to have primarily consumed flesh from fresh kills) and significantly greater variance in complexity values than S. fatalis. Ultimately, these results suggest that cougars already used or adopted a more generalized dietary strategy during the Pleistocene that may have been key to their subsequent success.", "keyphrases": ["late pleistocene extinction", "microwear texture analysis", "complexity", "cougar"]}
{"id": "paleo.009396", "title": "The oldest known digestive system consisting of both paired digestive glands and a crop from exceptionally preserved trilobites of the Guanshan Biota (Early Cambrian, China)", "abstract": "The early Cambrian Guanshan biota of eastern Yunnan, China, contains exceptionally preserved animals and algae. Most diverse and abundant are the arthropods, of which there are at least 11 species of trilobites represented by numerous specimens. Many trilobite specimens show soft-body preservation via iron oxide pseudomorphs of pyrite replacement. Here we describe digestive structures from two species of trilobite, Palaeolenus lantenoisi and Redlichia mansuyi. Multiple specimens of both species contain the preserved remains of an expanded stomach region (a \u201ccrop\u201d) under the glabella, a structure which has not been observed in trilobites this old, despite numerous examples of trilobite gut traces from other Cambrian Lagerst\u00e4tten. In addition, at least one specimen of Palaeolenus lantenoisi shows the preservation of an unusual combination of digestive structures: a crop and paired digestive glands along the alimentary tract. This combination of digestive structures has also never been observed in trilobites this old, and is rare in general, with prior evidence of it from one juvenile trilobite specimen from the late Cambrian Orsten fauna of Sweden and possibly one adult trilobite specimen from the Early Ordovician Fezouata Lagerst\u00e4tte. The variation in the fidelity of preservation of digestive structures within and across different Lagerst\u00e4tten may be due to variation in the type, quality, and point of digestion of food among specimens in addition to differences in mode of preservation. The presence and combination of these digestive features in the Guanshan trilobites contradicts current models of how the trilobite digestive system was structured and evolved over time. Most notably, the crop is not a derived structure as previously proposed, although it is possible that the relative size of the crop increased over the evolutionary history of the clade.", "keyphrases": ["digestive gland", "crop", "guanshan biota", "trilobite speciman"]}
{"id": "10.1146/annurev-ecolsys-110617-062231", "title": "Dinosaur Macroevolution and Macroecology", "abstract": "Dinosaurs were large-bodied land animals of the Mesozoic that gave rise to birds. They played a fundamental role in structuring Jurassic\u2013Cretaceous ecosystems and had physiology, growth, and reproductive biology unlike those of extant animals. These features have made them targets of theoretical macroecology. Dinosaurs achieved substantial structural diversity, and their fossil record documents the evolutionary assembly of the avian body plan. Phylogeny-based research has allowed new insights into dinosaur macroevolution, including the adaptive landscape of their body size evolution, patterns of species diversification, and the origins of birds and bird-like traits. Nevertheless, much remains unknown due to incompleteness of the fossil record at both local and global scales. This presents major challenges at the frontier of paleobiological research regarding tests of macroecological hypotheses and the effects of dinosaur biology, ecology, and life history on their macroevolution.", "keyphrases": ["macroecology", "ecology", "dinosaur macroevolution", "interest"]}
{"id": "10.1080/00438243.2015.1073119", "title": "Pleistocene rainforests: barriers or attractive environments for early human foragers?", "abstract": "Abstract In the 1980s, anthropologists argued that tropical rainforests were unattractive environments for long-term human navigation, subsistence and occupation. Meanwhile, archaeologists have traditionally held that Homo sapiens only intensively colonized rainforests during the Holocene, from c. 11 thousand years ago (ka). New discoveries and re-appraisal of Pleistocene (c. 200\u201312 ka) archaeological sites in Africa, Southeast Asia, Melanesia, and Sri Lanka, have, however, indicated the possibility for human occupation of rainforests from c. 45 ka and, more controversially, c. 200 ka. We critically review the archaeological evidence for Pleistocene human rainforest occupation from several regions. We argue that clear evidence exists for human adaptation to rainforest ecologies from c. 45 ka, with tantalizing hints of even earlier colonization. More research, however, is needed in order to understand the dynamism and diversity of palaeoecologies commonly classified as \u2018rainforest\u2019, as well as the regional extent, nature, and longevity of early human rainforest habitations.", "keyphrases": ["rainforest", "environment", "archaeologist", "southeast asia", "human occupation"]}
{"id": "10.1644/08-MAMM-A-347R1.1", "title": "When teeth and bones disagree: body mass estimation of a giant extinct rodent", "abstract": "Abstract Body size is correlated with virtually every morphological, physiological, and life-history trait in mammal species. As a consequence, estimates of body size of fossil species are often used for paleoecological reconstructions. Characters used as proxies for body mass in extinct species include teeth, skull, and skeletal measurements. We show that the body-mass estimates of extinct species from living taxa can be misleading and depend largely on the morphological variable selected as a proxy for body mass. We also discuss statistical tools that are available to assess the accuracy of body-mass estimates in extinct species. Here, we focus on the revision of the mass estimate of the giant Miocene fossil rodent Phoberomys pattersoni (Venezuela), the 2nd largest rodent ever reported, with an estimated body mass between 436 and 741 kg. This is far beyond the range of average body masses in living rodents, which vary from several grams to 40 kg. We conclude that body mass of Phoberomys was most likely overestimated. The species P. pattersoni likely weighed between 220 kg and 280 kg, the mass of a horse or a large antelope.", "keyphrases": ["mass estimate", "rodent", "tooth"]}
{"id": "paleo.004811", "title": "Increase in metazoan ecosystem engineering prior to the Ediacaran\u2013Cambrian boundary in the Nama Group, Namibia", "abstract": "The disappearance of the soft-bodied Ediacara biota at the Ediacaran\u2013Cambrian boundary potentially represents the earliest mass extinction of complex life, although the precise driver(s) of this extinction remain unresolved. The \u2018biotic replacement\u2019 model proposes that an evolutionary radiation of metazoan ecosystem engineers in the latest Ediacaran profoundly altered marine palaeoenvironments, resulting in the extinction of Ediacara biota and setting the stage for the subsequent Cambrian Explosion. However, metazoan ecosystem engineering across the Ediacaran\u2013Cambrian transition has yet to be quantified. Here, we test this key tenet of the biotic replacement model by characterizing the intensity of metazoan bioturbation and ecosystem engineering in trace fossil assemblages throughout the latest Ediacaran Nama Group in southern Namibia. The results illustrate a dramatic increase in both bioturbation and ecosystem engineering intensity in the latest Ediacaran, prior to the Cambrian boundary. Moreover, our analyses demonstrate that the highest-impact ecosystem engineering behaviours were present well before the onset of the Cambrian. These data provide the first support for a fundamental prediction of the biotic replacement model, and evidence for a direct link between the early evolution of ecosystem engineering and the extinction of the Ediacara biota.", "keyphrases": ["metazoan ecosystem engineering", "ediacaran\u2013cambrian boundary", "namibia", "biotic replacement"]}
{"id": "paleo.000109", "title": "PATTERN MATCHING: CLASSIFICATION OF AMMONITIC SUTURES USING GIS", "abstract": "Geographic Information Systems (GIS) is utilized to apply spatial analysis techniques to visually and quantitatively match ammonoid suture patterns for classification. The Turonian ammonite family Coilopoceratidae was chosen as the basis for this project, because the similar suture patterns within the family make species-level identification a challenge. A Coilopoceras springeri suture template was created by overlaying 10 different Coilopoceras springeri suture patterns, using the right holotype suture pattern as the basal or designation guide. Templates for Coilopoceras colleti and Hoplitoides sandovalensis sutures were constructed in the same manner. Sutures of known and unknown specimens were tested within the templates in order to identify species. The sutures of known specimens matched with the correct templates and did not compare well with other species' templates. Sutures of unknown specimens clearly fit within one template better than within others and, hence, could be reliably classified to the species level. In addition to species classification, the GIS method provides a mechanism for both visual and quantitative comparisons of individual sutures. This GIS method will aid professional and avocational paleontologists, biostratigraphers, and geologists in classifying ammonite species, and may help further our understanding of suture morphogenesis and function by providing a standard basis for morphological comparison of complex sutural patterns.", "keyphrases": ["gis", "geographic information systems", "suture pattern"]}
{"id": "paleo.004726", "title": "Data from: Spinosity, regeneration, and targeting among Paleozoic crinoids and their predators", "abstract": "Evolving interactions between predators and prey constitute one of the major adaptive influences on marine animals during the Paleozoic. Crinoids and fish constitute a predator-prey system that may date back to at least the Silurian, as suggested by patterns of crinoid regeneration and spinosity in concert with changes in the predatory fauna. Here we present data on the frequency of breakage and regeneration in the spines of the Middle Devonian camerate Gennaeocrinus and late Paleozoic cladids, as well as an expanded survey of the prevalence of spinosity and infestation by platyceratid gastropods on crinoid genera during the Paleozoic. Spine regeneration frequency in the measured populations is comparable to arm regeneration frequencies from Mississippian Rhodocrinites and from modern deepwater crinoid populations. The prevalence of spinosity varies by taxon, time, and anatomy among Paleozoic crinoids; notably, spinosity in camerates increased from the Silurian through the Mississippian and decreased sharply during the Pennsylvanian, whereas spines were uncommon in cladids until their Late Mississippian diversification. Among camerates, tegmen spinosity is positively correlated with the presence of infesting platyceratid gastropods. These results allow us to evaluate several hypotheses for the effects of predation on morphological differences between early, middle, and late Paleozoic crinoid faunas. Our data corroborate the hypothesis that predators targeted epibionts on camerate crinoids and anal sacs on advanced cladids and suggest that the replacement of shearing predators by crushing predators after the Hangenberg extinction affected the locations of spines in Mississippian camerates.", "keyphrases": ["spinosity", "paleozoic crinoid", "predator", "spine"]}
{"id": "paleo.009808", "title": "The Origin of the Legumes is a Complex Paleopolyploid Phylogenomic Tangle Closely Associated with the Cretaceous\u2013Paleogene (K\u2013Pg) Mass Extinction Event", "abstract": "Abstract The consequences of the Cretaceous\u2013Paleogene (K\u2013Pg) boundary (KPB) mass extinction for the evolution of plant diversity remain poorly understood, even though evolutionary turnover of plant lineages at the KPB is central to understanding assembly of the Cenozoic biota. The apparent concentration of whole genome duplication (WGD) events around the KPB may have played a role in survival and subsequent diversification of plant lineages. To gain new insights into the origins of Cenozoic biodiversity, we examine the origin and early evolution of the globally diverse legume family (Leguminosae or Fabaceae). Legumes are ecologically (co-)dominant across many vegetation types, and the fossil record suggests that they rose to such prominence after the KPB in parallel with several well-studied animal clades including Placentalia and Neoaves. Furthermore, multiple WGD events are hypothesized to have occurred early in legume evolution. Using a recently inferred phylogenomic framework, we investigate the placement of WGDs during early legume evolution using gene tree reconciliation methods, gene count data and phylogenetic supernetwork reconstruction. Using 20 fossil calibrations we estimate a revised timeline of legume evolution based on 36 nuclear genes selected as informative and evolving in an approximately clock-like fashion. To establish the timing of WGDs we also date duplication nodes in gene trees. Results suggest either a pan-legume WGD event on the stem lineage of the family, or an allopolyploid event involving (some of) the earliest lineages within the crown group, with additional nested WGDs subtending subfamilies Papilionoideae and Detarioideae. Gene tree reconciliation methods that do not account for allopolyploidy may be misleading in inferring an earlier WGD event at the time of divergence of the two parental lineages of the polyploid, suggesting that the allopolyploid scenario is more likely. We show that the crown age of the legumes dates to the Maastrichtian or early Paleocene and that, apart from the Detarioideae WGD, paleopolyploidy occurred close to the KPB. We conclude that the early evolution of the legumes followed a complex history, in which multiple auto- and/or allopolyploidy events coincided with rapid diversification and in association with the mass extinction event at the KPB, ultimately underpinning the evolutionary success of the Leguminosae in the Cenozoic. [Allopolyploidy; Cretaceous\u2013Paleogene (K\u2013Pg) boundary; Fabaceae, Leguminosae; paleopolyploidy; phylogenomics; whole genome duplication events]", "keyphrases": ["cretaceous\u2013paleogene", "k\u2013pg", "mass extinction event"]}
{"id": "paleo.012796", "title": "Insights into the 400 million-year-old eyes of giant sea scorpions (Eurypterida) suggest the structure of Palaeozoic compound eyes", "abstract": "Sea scorpions (Eurypterida, Chelicerata) of the Lower Devonian (~400 Mya) lived as large, aquatic predators. The structure of modern chelicerate eyes is very different from that of mandibulate compound eyes [Mandibulata: Crustacea and Tracheata (Hexapoda, such as insects, and Myriapoda)]. Here we show that the visual system of Lower Devonian (~400 Mya) eurypterids closely matches that of xiphosurans (Xiphosura, Chelicerata). Modern representatives of this group, the horseshoe crabs (Limulidae), have cuticular lens cylinders and usually also an eccentric cell in their sensory apparatus. This strongly suggests that the xiphosuran/eurypterid compound eye is a plesiomorphic structure with respect to the Chelicerata, and probably ancestral to that of Euchelicerata, including Eurypterida, Arachnida and Xiphosura. This is supported by the fact that some Palaeozoic scorpions also possessed compound eyes similar to those of eurypterids. Accordingly, edge enhancement (lateral inhibition), organised by the eccentric cell, most useful in scattered light-conditions, may be a very old mechanism, while the single-lens system of arachnids is possibly an adaptation to a terrestrial life-style.", "keyphrases": ["sea scorpion", "compound eye", "arachnid"]}
{"id": "10.1073/pnas.262659599", "title": "Biological skeletal carbonate records changes in major-ion chemistry of paleo-oceans", "abstract": "The history of the chemical evolution of seawater is of first-order importance given its fundamental role in a broad spectrum of geologic, geochemical, and paleontologic phenomena. A growing body of evidence for a more dynamic evolution of seawater chemistry than previously considered has been building over the past two decades. Central to this body of evidence are oscillating global trends, on a 100- to 200-million-year time scale, in the mineralogy of marine carbonate cements (1), late-stage salts in marine evaporites (2), and calcifying organisms that are interpreted to record secular change in seawater chemistry (3, 4). The degree to which the basic seawater signal has varied over the past 550 million years is, however, an issue that has been strongly debated in the literature (e.g., refs. 5\u20139). This primarily reflects the arguably equivocal nature of the evidence used to infer secular changes in seawater chemistry and the mechanisms for driving that change. Reconstructions of seawater chemical composition based on marine inorganic precipitate and fossil proxy records may be compromised by the influence of various environmental factors, and by the geochemical insults of diagenesis on their mineralogy and chemical composition (5, 10, 11). Complimentary modeling efforts that focus on constraining the mechanism(s) for driving substantial chemical change in seawater are challenged by the uncertainties associated with defining model input parameters (2, 5, 9). The degree to which the basic seawater signal has varied over the past 550 million years is an issue that has been strongly debated. \n\nIn a recent issue of PNAS, Stanley et al. (12) provide compelling, experimentally derived evidence that the skeletal carbonate of biologically simple marine organisms, analogous to inorganic marine carbonate, has the potential to record faithfully changes in the major-ion chemistry of paleo-oceans. Their results, in concert with recently published \u2026", "keyphrases": ["major-ion chemistry", "paleo-ocean", "seawater chemistry", "biomineralogy", "simple clade"]}
{"id": "10.1111/j.1502-3931.2012.00329.x", "title": "Large tetrapod burrows from the Middle Triassic of Argentina: a behavioural adaptation to seasonal semi-arid climate?", "abstract": "Krapovickas, V., Mancuso, A.C., Marsicano, C.A., Domnanovich, N.S. & Schultz, C.L. 2013: Large tetrapod burrows from the Middle Triassic of Argentina: a behavioural adaptation to seasonal semi-arid climate? Lethaia, Vol. 46, pp. 154\u2013169. \n \n \n \nWe report the discovery of large burrow casts in the early Middle Triassic Tarjados Formation, at Talampaya National Park, north-western Argentina. Facies analysis indicates the burrows are preserved in sandbars deposited by an ephemeral river under semi-arid and seasonal climatic conditions. The structures are mostly preserved in longitudinal cross-section and consist of an opening, an inclined tunnel (ramp), and a terminal chamber. The ramp is 8\u201314\u00a0cm in height, up to 130\u00a0cm in length and penetrates 49\u201363\u00a0cm bellow the palaeosurface with an inclination of 22\u00b0\u201330\u00b0. We studied burrow cast dimensions, overall architectural morphology, surficial marks, and compared them with other large burrows of both invertebrate and vertebrate origin. A tetrapod origin of the burrow casts was established based on: distinctive architecture, and size, which is more than twice the most common size range for large terrestrial invertebrate burrows. Comparison with other Upper Permian and Triassic tetrapod burrows allows us to identify three general morphological groups: (1) simple inclined burrows; (2) helical burrows; and (3) burrow network complexes, representing different behaviours. A study of tetrapod body fossils preserved within other Upper Permian and Triassic burrows shows that the Tarjados structures were most likely produced by non-mammalian cynodonts. The environmental and climatic context suggests that aridity and seasonality played a fundamental role selecting burrowing behaviour in therapsids and that by the Early\u2013Middle Triassic their burrowing behaviour attained a complexity comparable to modern mammals. \u25a1Argentina, behaviour, palaeoclimate, Permo-Triassic, Tarjados Formation, Tetrapod burrows.", "keyphrases": ["tetrapod burrow", "middle triassic", "behaviour", "seasonal semi-arid climate"]}
{"id": "10.5194/gmd-8-2465-2015", "title": "PISCES-v2: an ocean biogeochemical model for carbon and ecosystem studies", "abstract": "Abstract. PISCES-v2 (Pelagic Interactions Scheme for Carbon and Ecosystem Studies volume 2) is a biogeochemical model which simulates the lower trophic levels of marine ecosystems (phytoplankton, microzooplankton and mesozooplankton) and the biogeochemical cycles of carbon and of the main nutrients (P, N, Fe, and Si). The model is intended to be used for both regional and global configurations at high or low spatial resolutions as well as for short-term (seasonal, interannual) and long-term (climate change, paleoceanography) analyses. There are 24 prognostic variables (tracers) including two phytoplankton compartments (diatoms and nanophytoplankton), two zooplankton size classes (microzooplankton and mesozooplankton) and a description of the carbonate chemistry. Formulations in PISCES-v2 are based on a mixed Monod\u2013quota formalism. On the one hand, stoichiometry of C / N / P is fixed and growth rate of phytoplankton is limited by the external availability in N, P and Si. On the other hand, the iron and silicon quotas are variable and the growth rate of phytoplankton is limited by the internal availability in Fe. Various parameterizations can be activated in PISCES-v2, setting, for instance, the complexity of iron chemistry or the description of particulate organic materials. So far, PISCES-v2 has been coupled to the Nucleus for European Modelling of the Ocean (NEMO) and Regional Ocean Modeling System (ROMS) systems. A full description of PISCES-v2 and of its optional functionalities is provided here. The results of a quasi-steady-state simulation are presented and evaluated against diverse observational and satellite-derived data. Finally, some of the new functionalities of PISCES-v2 are tested in a series of sensitivity experiments.", "keyphrases": ["ocean", "biogeochemical model", "nutrient", "availability", "pisces-v2"]}
{"id": "paleo.001981", "title": "Simulating Miocene Warmth: Insights From an Opportunistic Multi\u2010Model Ensemble (MioMIP1)", "abstract": "The Miocene epoch, spanning 23.03\u20135.33 Ma, was a dynamic climate of sustained, polar amplified warmth. Miocene atmospheric CO2 concentrations are typically reconstructed between 300 and 600 ppm and were potentially higher during the Miocene Climatic Optimum (16.75\u201314.5 Ma). With surface temperature reconstructions pointing to substantial midlatitude and polar warmth, it is unclear what processes maintained the much weaker\u2010than\u2010modern equator\u2010to\u2010pole temperature difference. Here, we synthesize several Miocene climate modeling efforts together with available terrestrial and ocean surface temperature reconstructions. We evaluate the range of model\u2010data agreement, highlight robust mechanisms operating across Miocene modeling efforts and regions where differences across experiments result in a large spread in warming responses. Prescribed CO2 is the primary factor controlling global warming across the ensemble. On average, elements other than CO2, such as Miocene paleogeography and ice sheets, raise global mean temperature by \u223c2\u00b0C, with the spread in warming under a given CO2 concentration (due to a combination of the spread in imposed boundary conditions and climate feedback strengths) equivalent to \u223c1.2 times a CO2 doubling. This study uses an ensemble of opportunity: models, boundary conditions, and reference data sets represent the state\u2010of\u2010art for the Miocene, but are inhomogeneous and not ideal for a formal intermodel comparison effort. Acknowledging this caveat, this study is nevertheless the first Miocene multi\u2010model, multi\u2010proxy comparison attempted so far. This study serves to take stock of the current progress toward simulating Miocene warmth while isolating remaining challenges that may be well served by community\u2010led efforts to coordinate modeling and data activities within a common analytical framework.", "keyphrases": ["miocene warmth", "miomip1", "surface temperature reconstruction", "global warming", "ice sheet"]}
{"id": "10.1159/000487248", "title": "Identification of in vivo Sulci on the External Surface of Eight Adult Chimpanzee Brains: Implications for Interpreting Early Hominin Endocasts", "abstract": "The only direct source of information about hominin brain evolution comes from the fossil record of endocranial casts (endocasts) that reproduce details of the external morphology of the brain imprinted on the walls of the braincase during life. Surface traces of sulci that separate the brain\u2019s convolutions (gyri) are reproduced sporadically on early hominin endocasts. Paleoneurologists rely heavily on published descriptions of sulci on brains of great apes, especially chimpanzees (humans\u2019 phylogenetically closest living relatives), to guide their identifications of sulci on ape-sized hominin endocasts. However, the few comprehensive descriptions of cortical sulci published for chimpanzees usually relied on post mortem brains, (now) antiquated terminology for some sulci, and photographs or line drawings from limited perspectives (typically right or left lateral views). The shortage of adequate descriptions of chimpanzee sulcal patterns partly explains why the identities of certain sulci on australopithecine endocasts (e.g., the inferior frontal and middle frontal sulci) have been controversial. Here, we provide images of lateral and dorsal surfaces of 16 hemispheres from 4 male and 4 female adult chimpanzee brains that were obtained using in vivo magnetic resonance imaging. Sulci on the exposed surfaces of the frontal, parietal, temporal, and occipital lobes are identified on the images based on their locations, positions relative to each other, and homologies known from comparative studies of cytoarchitecture in primates. These images and sulcal identifications exceed the quantity and quality of previously published illustrations of chimpanzee brains with comprehensively labeled sulci and, thus, provide a larger number of examples for identifying sulci on hominin endocasts than hitherto available. Our findings, even in a small sample like the present one, overturn published claims that australopithecine endocasts reproduce derived configurations of certain sulci in their frontal lobes that never appear on chimpanzee brains. The sulcal patterns in these new images also suggest that changes in two gyri that bridge between the parietal and occipital lobes may have contributed to cortical reorganization in early hominins. It is our hope that these labeled in vivo chimpanzee brains will assist future researchers in identifying sulci on hominin endocasts, which is a necessary first step in the quest to learn how and when the external morphology of the human cerebral cortex evolved from apelike precursors.", "keyphrases": ["sulci", "chimpanzee", "identification"]}
{"id": "paleo.003821", "title": "Large, unwebbed bird and bird\u2010like footprints from the Mesozoic and Cenozoic: a review of ichnotaxonomy and trackmaker affinity", "abstract": "The Mesozoic and Cenozoic track record of large birds (avian theropods) with footprint lengths (FL) > 10.0 cm is quite limited, whereas small tracks (FL < 10.0 cm) are abundant from the Early Cretaceous onwards. This large versus small threshold value is consistent with the track record of extant birds among which only \u02dc10% are large, and so is scaled appropriately to Class Aves. The proportion of large pachydactylous (thick-toed) or robust non-avian theropod ichnotaxa reported from the Mesozoic considerably exceeds the few large leptodactylous (thin-toed) or gracile forms such as Archaeornithipus and Magnoavipes, named, albeit controversially, to suggest avian affinity. The Cenozoic record of large avian tracks is quite different, with large pachydactylous tracks limited to a few Eocene-Oligocene (Palaeogene) ichnogenera (Ornithoformipes and Rivavipes), and rare unnamed Neogene and Holocene dinornithiform tracks. Thus, large flightless species are less well represented by tracks than body fossils. This suggests probable preservational bias in favour of waterbird or shorebird-like tracks in shoreline facies. However, the Cenozoic record of large leptodactylous tracks attributable to cranes, herons and related trackmakers is quite extensive, mostly confined to the Neogene and formally named to suggest representatives of extant avian clades capable of flight. These distribution patterns apparently reflect the dominance of large pachydactylous non-avian and avian theropods in the Mesozoic and early Palaeogene, and contrast with the rise of large, as well ongoing diversification of smaller leptodactylous Aequornithes in the Neogene. These distribution patterns in space and time likely reflect changing selection pressures as today's modern avifauna evolved. \u25a1bird, Cenozoic, footprints, ichnospecies, ichnotaxabase.", "keyphrases": ["footprint", "cenozoic", "avian track"]}
{"id": "10.1080/14772019.2016.1149115", "title": "A new family of gymnodont fish (Tetraodontiformes) from the earliest Eocene of the Peri-Tethys (Kabardino-Balkaria, northern Caucasus, Russia)", "abstract": "The environmental changes that occurred during the Paleocene\u2013Eocene transition are crucial for the interpretation of the patterns and processes of diversification of vertebrate clades. A prominent increase of the number of vertebrate families occurred between the late Paleocene and early Eocene, resulting in the appearance of many in the earliest representatives of extant lineages, including a number of marine fish groups. Tetraodontiforms are a monophyletic group of derived teleost fishes encompassing a variety of bizarre morphologies. Even though the earliest members of this order appeared in the Late Cretaceous, most of the crown lineages date back to the Eocene. One of the crown tetraodontiform groups that appeared in the fossil record during the Eocene are the gymnodonts (pufferfishes, porcupinefishes, ocean sunfishes and their allies), which include a variety of species characterized by highly modified teeth incorporated into beak-like jaws and scales usually modified into prickly spines. Herein, we describe \u2020Balkaria histiopterygia gen. et sp. nov., a gymnodont fish characterized by a strikingly peculiar morphology. The single available specimen in part and counterpart documented herein was recovered from the sapropelitic deposits that originated in the northern Peri-Tethys during the transition between the Paleocene and Eocene. Today, these deposits are exposed near the village of Gerpegezh, Republic of Kabardino-Balkaria, Russia. The skeletal structure reveals an extreme mosaicism of primitive and derived characters that result in a very bizarre and unexpected morphology. \u2020Balkaria histiopterygia gen. et sp. nov. is unique among the extant and other fossil gymnodont fishes by, among many other features, the huge size of its spiny-dorsal fin and the position of these spines on the top of the head. \u2020Balkaria histiopterygia gen. et sp. nov. is the earliest unequivocal gymnodont fish, representing the sole member of the new family \u2020Balkariidae. More particularly, \u2020Balkaria histiopterygia gen. et sp. nov. is shown herein to be the oldest and arguably the most informative fossil of the gymnodont suborder Tetraodontoidei. The phylogenetic placement of this new taxon has been assessed based on both morphology alone and on a combination of morphological and molecular data that strongly supports the close relationship of \u2020Balkaria gen. nov. to the herein restricted Tetraodontoidei. However, its position within Tetraodontoidei is unstable depending on the type of method of phylogenetic inference. Significantly younger ages, during the Late Cretaceous, are estimated for the diversification of Tetraodontiformes than in previous tip-dating analyses (Jurassic and Early Cretaceous) using the fossilized birth-death process; these new age estimates are in better agreement with the tetraodontiform fossil record. http://zoobank.org/urn:lsid:zoobank.org:pub:41764800-B0D8-4CA4-A111-5F4C4A281C37", "keyphrases": ["gymnodont fish", "tetraodontiformes", "vertebrate family", "early eocene"]}
{"id": "10.1111/2041-210X.13299", "title": "layeranalyzer: Inferring correlative and causal connections from time series data in r", "abstract": "Distinguishing correlative and causal connections among time series is an important challenge in evolutionary biology, ecology, macroevolution and palaeobiology. Here, we present layeranalyzer, an r package that uses linear stochastic differential equations as a tool for parametrically describing evolutionary and ecological processes and for modelling temporal correlation and Granger causality between two or more time series. We describe the basic functions in layeranalyzer and briefly discuss modelling strategies by demonstrating our tool with three disparate case studies. First, we model a single time series of phenotypic evolution in a bird species; second, we extract cyclical connections in the well\u2010known hare\u2010lynx dataset; third, we infer the correlative and causal connections among the genus origination and extinction rates of brachiopods and bivalves. We summarize the advantages and limitations of using linear stochastic differential equations and layeranalyzer for studying correlative and causal connections.", "keyphrases": ["causal connection", "equation", "extinction rate", "layeranalyzer"]}
{"id": "paleo.008366", "title": "Covariance of sutural complexity with whorl shape: evidence from intraspecific analyses of the Cretaceous ammonoid Desmoceras", "abstract": "In order to test the hypothesis that complex suture lines in ammonoids reinforced their shell strength, intraspecific variation of sutural complexity and shell morphologies (whorl shape and septal thickness) of the Cretaceous ammonoid Desmoceras latidorsatum (including three forms) from Madagascar were analyzed. The comparison between the sutural complexity and the whorl shape demonstrated that the more compressed or depressed forms have more complex suture lines than intermediate forms.\nThe more compressed or depressed shells are generally expected to be weaker than intermediate ones that have almost circular whorl cross-sections. A comparison between sutural complexity balance (the ratio of the sutural complexities of the ventral and lateral parts) with the whorl shape demonstrated that the suture lines are more complex in the lateral area of the compressed shells and in the ventral area of the depressed shells. These relationships suggest that the suture lines were more complex in relatively more flattened parts of phragmocones, supporting that the complex suture reinforced the phragmocone against hydrostatic pressure.", "keyphrases": ["sutural complexity", "whorl shape", "intraspecific variation"]}
{"id": "paleo.012043", "title": "New Data on the Clevosaurus (Sphenodontia: Clevosauridae) from the Upper Triassic of Southern Brazil", "abstract": "The sphenodontian fossil record in South America is well known from Mesozoic and Paleogene deposits of Argentinean Patagonia, mainly represented by opisthodontians, or taxa closely related to the modern Sphenodon. In contrast, the Brazilian fossil record is restricted to the Caturrita Formation, Late Triassic of Rio Grande do Sul, represented by several specimens of Clevosauridae, including Clevosaurus brasiliensis Bonaparte and Sues, 2006. Traditionally, Clevosauridae includes several Late Triassic to Early Jurassic taxa, such as Polysphenodon, Brachyrhinodon, and Clevosaurus, the latter well-represented by several species. The detailed description of the specimen MCN-PV 2852 allowed the first systematic revision of most Clevosaurus species. Within Clevosauridae, Polysphenodon is the most basal taxon, and an IterPCR analysis revealed Brachrhynodon as a possible Clevosaurus; C. petilus, C. wangi, and C. mcgilli as possibly distinct taxonomic entities; and the South African Clevosaurus sp. is not closely related to C. brasiliensis. These data indicate the need of a deep phylogenetic review of Clevosauridae, in order to discover synapomorphic characters among the diversity of these Triassic/Jurassic sphenodontians.", "keyphrases": ["clevosaurus", "clevosauridae", "opisthodontian", "review", "phylogenetic analysis"]}
{"id": "10.1002/dep2.204", "title": "Palaeocene to Miocene southern Tethyan carbonate factories: A meta\u2010analysis of the successions of South\u2010western and Western Central Asia", "abstract": "One hundred and forty\u2010four published successions of shallow\u2010water carbonates, deposited between the Palaeocene and the Miocene, from the Levant to the Himalayas, have been re\u2010analysed using a standardised approach to investigate the distribution of carbonate facies and carbonate\u2010producing organisms. Large benthic foraminifera were found to be the volumetrically most important group of carbonate producers during the whole period, with a peak in abundance during the Eocene. Colonial corals are relatively abundant during the Palaeocene and Miocene, their abundance peaks during the Oligocene and has a minimum during the Eocene. Red calcareous algae have a similar pattern although their peak in abundance covers both the Oligocene and Miocene. Green calcareous algae decrease from the Palaeocene onward. Facies related to very shallow and/or restricted marine conditions peak during the Miocene and in particular during the Aquitanian. Both the pattern of large benthic foraminifera and of colonial corals seems to be related to temperature, with warm periods favouring the former group and cool periods the latter group. Red calcareous algae display a pattern similar to that of colonial corals suggesting that the periods favourable for one group are, on a large scale, also favourable for the other. The progressive decrease of green calcareous alga could be tentatively related to a preservation bias connected to the transition from Palaeogene assemblages that included presumably calcitic taxa of green algae to Neogene assemblages entirely constituted by aragonitic taxa with limited preservation potential. The Aquitanian peak in facies related to very shallow and/or restricted marine conditions is most likely connected to the progressive narrowing of the Tethys related to the collision between Arabia and Eurasia. These results denote an overall agreement between the abundance of the various types of shallow\u2010water carbonate facies and large\u2010scale environmental and geological processes, highlighting the potential for palaeoenvironmental reconstruction locked in the shallow\u2010water record.", "keyphrases": ["succession", "carbonate producer", "palaeocene"]}
{"id": "paleo.011189", "title": "Bony labyrinth morphology clarifies the origin and evolution of deer", "abstract": "Deer are an iconic group of large mammals that originated in the Early Miocene of Eurasia (ca. 19 Ma). While there is some consensus on key relationships among their members, on the basis of molecular- or morphology-based analyses, or combined approaches, many questions remain, and the bony labyrinth has shown considerable potential for the phylogenetics of this and other groups. Here we examine its shape in 29 species of living and fossil deer using 3D geometric morphometrics and cladistics. We clarify several issues of the origin and evolution of cervids. Our results give new age estimates at different nodes of the tree and provide for the first time a clear distinction of stem and crown Cervidae. We unambiguously attribute the fossil Euprox furcatus (13.8 Ma) to crown Cervidae, pushing back the origin of crown deer to (at least) 4 Ma. Furthermore, we show that Capreolinae are more variable in bony labyrinth shape than Cervinae and confirm for the first time the monophyly of the Old World Capreolinae (including the Chinese water deer Hydropotes) based on morphological characters only. Finally, we provide evidence to support the sister group relationship of Megaloceros giganteus with the fallow deer Dama.", "keyphrases": ["deer", "morphometric", "bony labyrinth"]}
{"id": "10.1139/cjes-2014-0057", "title": "Isotopic characterization of organic matter from the Danek Bonebed (Edmonton, Alberta, Canada) with special reference to amber", "abstract": "During the course of excavating the Maastrichtian Danek Bonebed in the city of Edmonton, a range of well-preserved organic materials was recovered alongside vertebrate remains, including amber, coal, and unpermineralized plant fragments. Herein, we report carbon and hydrogen stable isotopic characterizations of these materials to provide ancillary insights into genesis of the fossil deposit. These analyses permit isotopic comparisons between the various organic fractions at the Danek locality, as well as with other Late Cretaceous localities in Alberta. The investigation of amber proves particularly informative, with carbon stable isotope ratios that are regionally consistent and furthermore conform to the larger, global-scale isotopic trend for this material, and hydrogen results that inform paleoclimatic conditions at the time of amber formation. When coupled with chemotaxonomic information from amber Fourier-transform infrared spectroscopy, the isotopic results indicate a consistent taxodioid forest composition and relatively stable environmental conditions across the three horizons that encap- sulate the Danek bonebed. Resume : Au cours de l'excavation du Danek Bonebed (Maastrichtien) dans la ville d'Edmonton, une gamme de materiaux organiques bien conserves a ete recuperee tout pres de restes de vertebres; ces materiaux comprennent de l'ambre, du charbon et des fragments de plantes non permineralises. Dans cet article, nous presentons les caracterisations des isotopes stables carbone et hydrogene de ces materiaux afin de fournir des points de vue supplementaires sur la genese du depot fossilifere. Ces analyses permettent de comparer les isotopes des diverses fractions organiques al'emplacement Danek et ad'autres localites du Cretace tardif en Alberta. L'etude de l'ambre s'est averee particulierement informative. En effet, les rapports stables des isotopes du carbone sont constants atravers la region et, de plus, ils concordent avec la tendance isotopique aplus grande echelle pour ce materiau et avec les resultats pour l'hydrogene qui donnent des indices quant aux conditions paleoclimatiques au moment de la formation de l'ambre. Lorsque jumeles al'information chimiotaxonomique d'une spectroscopie infrarouge atransformation de Fourier de l'ambre, les resultats isotopiques indiquent une composition de foret taxodioide et des conditions environnemen- tales relativement stables atravers les trois horizons qui contiennent le \u00ab lit d'os \u00bb de Danek. (Traduit par le Redaction)", "keyphrases": ["danek bonebed", "alberta", "isotopic characterization"]}
{"id": "paleo.001528", "title": "Another one bites the dust: faecal silica levels in large herbivores correlate with high-crowned teeth", "abstract": "The circumstances of the evolution of hypsodonty (= high-crowned teeth) are a bone of contention. Hypsodonty is usually linked to diet abrasiveness, either from siliceous phytoliths (monocotyledons) or from grit (dusty environments). However, any empirical quantitative approach testing the relation of ingested silica and hypsodonty is lacking. In this study, faecal silica content was quantified as acid detergent insoluble ash and used as proxy for silica ingested by large African herbivores of different digestive types, feeding strategies and hypsodonty levels. Separate sample sets were used for the dry (n = 15 species) and wet (n = 13 species) season. Average faecal silica contents were 17\u201346 g kg\u22121 dry matter (DM) for browsing and 52\u2013163 g kg\u22121 DM for grazing herbivores. No difference was detected between the wet (97.5 \u00b1 14.4 g kg\u22121 DM) and dry season (93.5 \u00b1 13.7 g kg\u22121 DM) faecal silica. In a phylogenetically controlled analysis, a strong positive correlation (dry season r = 0.80, p < 0.0005; wet season r = 0.74, p < 0.005) was found between hypsodonty index and faecal silica levels. While surprisingly our results do not indicate major seasonal changes in silica ingested, the correlation of faecal silica and hypsodonty supports a scenario of a dominant role of abrasive silica in the evolution of high-crowned teeth.", "keyphrases": ["faecal silica level", "herbivore", "ash", "dry matter", "high-crowned tooth"]}
{"id": "paleo.006736", "title": "\u2018CLAMP Online\u2019: a new web-based palaeoclimate tool and its application to the terrestrial Paleogene and Neogene of North America", "abstract": "CLAMP Online is a new form-driven web facility enabling Climate Leaf Analysis Multivariate Program (CLAMP) palaeoclimate determinations to be conducted in their entirety without the need for additional software. This facility is demonstrated using physiognomic data from 82 Eocene to Pliocene fossil sites in North America, the Physg3brc CLAMP calibration file, and both locally derived climate data (Met3br) and 0.5\u00b0\u00d70.5\u00b0gridded climate data (GRIDMet3br). All the fossil sites fall within the physiognomic space defined by the Physg3brc dataset showing the versatility of this calibration for Paleogene to Present sites in North America. The fossil sites also plot in the mesic part of physiognomic space confirming that the source of the fossil material was vegetation growing under conditions where water was not growth-limiting to any significant degree. Regression equations are derived relating the local to the gridded climate predictions showing the relative predictive capabilities of each dataset, as well as offering ways to convert previously published data between the two calibrations. Palaeoclimate data (mean annual, warm month mean and cold month mean temperatures, growing season length, growing season and mean monthly growing season precipitation, precipitation during the three consecutive wettest and three consecutive driest months, and annual averages for relative and specific humidities and enthalpy) are given for all 82 sites.", "keyphrases": ["clamp online", "paleogene", "north america", "vegetation"]}
{"id": "10.1080/14772011003594870", "title": "A reappraisal of the Cretaceous non-avian dinosaur faunas from Australia and New Zealand: evidence for their Gondwanan affinities", "abstract": "It has often been assumed that Australasian Cretaceous dinosaur faunas were for the most part endemic, but with some Laurasian affinities. In this regard, some Australasian dinosaurs have been considered Jurassic relicts, while others were thought to represent typical Laurasian forms or endemic taxa. Furthermore, it has been proposed that some dinosaurian lineages, namely oviraptorosaurians, dromaeosaurids, ornithomimosaurians and protoceratopsians, may have originated in Australia before dispersing to Asia during the Early Cretaceous. Here we provide a detailed review of Cretaceous non-avian dinosaurs from Australia and New Zealand, and compare them with taxa from other Gondwanan landmasses. Our results challenge the traditional view of Australian dinosaur faunas, with the majority of taxa displaying affinities that are concordant with current palaeobiogeographic models of Gondwanan terrestrial vertebrate faunal distribution. We reinterpret putative Australian \u2018hypsilophodontids\u2019 as basal ornithopods (some of them probably related to South American forms), and the recently described protoceratopsians are referred to Genasauria indet. and Ornithopoda indet. Among Theropoda, the Australian pigmy \u2018Allosaurus\u2019 is referred to the typical Gondwanan clade Abelisauroidea. Similarities are also observed between the enigmatic Australian theropod Rapator, Australovenator and the South American carcharodontosaurian Megaraptor. Timimus and putative oviraptorosaurians are referred to Dromaeosauridae. The present revision demonstrates that Australia's non-avian Cretaceous dinosaurian faunas were reminiscent of those found in other, roughly contemporaneous, Gondwanan landmasses, and are suggestive of faunal interchange with these regions via Antarctica.", "keyphrases": ["dinosaur faunas", "new zealand", "fulgurotherium australe"]}
{"id": "10.1098/rspb.2012.1473", "title": "Stable isotopes provide independent support for the use of mesowear variables for inferring diets in African antelopes", "abstract": "We examine the relationship between mesowear variables and carbon and nitrogen isotopes in 16 species of African antelope (Mammalia: Bovidae). We show significant differences in carbon and nitrogen isotope values between individuals exhibiting sharp versus round cusps, and high versus low occlusal relief. We show significant correlations between mesowear variables and both carbon and nitrogen isotopes. We find significant correlations between mesowear score and nitrogen, but not carbon isotopes. Finally, we find no significant correlations between hypsodonty index and either isotope examined. Our results provide strong support for the use of mesowear variables in palaeodietary reconstructions of antelopes. Our results further suggest that for the antelopes examined here, mesowear signals are a direct result of diet, while hyposodonty may be the result of phylogenetic legacy.", "keyphrases": ["isotope", "mesowear variable", "african antelope"]}
{"id": "10.7717/peerj.12094", "title": "Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem", "abstract": "First appearing in the latest Cretaceous, Crocodylia is a clade of semi-aquatic, predatory reptiles, defined by the last common ancestor of extant alligators, caimans, crocodiles, and gharials. Despite large strides in resolving crocodylian interrelationships over the last three decades, several outstanding problems persist in crocodylian systematics. Most notably, there has been persistent discordance between morphological and molecular datasets surrounding the affinities of the extant gharials, Gavialis gangeticus and Tomistoma schlegelii. Whereas molecular data consistently support a sister taxon relationship, in which they are more closely related to crocodylids than to alligatorids, morphological data indicate that Gavialis is the sister taxon to all other extant crocodylians. Here we present a new morphological dataset for Crocodylia based on a critical reappraisal of published crocodylian character data matrices and extensive firsthand observations of a global sample of crocodylians. This comprises the most taxonomically comprehensive crocodylian dataset to date (144 OTUs scored for 330 characters) and includes a new, illustrated character list with modifications to the construction and scoring of characters, and 46 novel characters. Under a maximum parsimony framework, our analyses robustly recover Gavialis as more closely related to Tomistoma than to other extant crocodylians for the first time based on morphology alone. This result is recovered regardless of the weighting strategy and treatment of quantitative characters. However, analyses using continuous characters and extended implied weighting (with high k-values) produced the most resolved, well-supported, and stratigraphically congruent topologies overall. Resolution of the gharial problem reveals that: (1) several gavialoids lack plesiomorphic features that formerly drew them towards the stem of Crocodylia; and (2) more widespread similarities occur between species traditionally divided into tomistomines and gavialoids, with these interpreted here as homology rather than homoplasy. There remains significant temporal incongruence regarding the inferred divergence timing of the extant gharials, indicating that several putative gavialids (\u2018thoracosaurs\u2019) are incorrectly placed and require future re-appraisal. New alligatoroid interrelationships include: (1) support for a North American origin of Caimaninae in the latest Cretaceous; (2) the recovery of the early Paleogene South American taxon Eocaiman as a \u2018basal\u2019 alligatoroid; and (3) the paraphyly of the Cenozoic European taxon Diplocynodon. Among crocodyloids, notable results include modifications to the taxonomic content of Mekosuchinae, including biogeographic affinities of this clade with latest Cretaceous\u2013early Paleogene Asian crocodyloids. In light of our new results, we provide a comprehensive review of the evolutionary and biogeographic history of Crocodylia, which included multiple instances of transoceanic and continental dispersal.", "keyphrases": ["new morphological dataset", "crocodylia", "problem", "gavialis"]}
{"id": "paleo.008550", "title": "Dietary diversity and evolution of the earliest flying vertebrates revealed by dental microwear texture analysis", "abstract": "Pterosaurs, the first vertebrates to evolve active flight, lived between 210 and 66 million years ago. They were important components of Mesozoic ecosystems, and reconstructing pterosaur diets is vital for understanding their origins, their roles within Mesozoic food webs and the impact of other flying vertebrates (i.e. birds) on their evolution. However, pterosaur dietary hypotheses are poorly constrained as most rely on morphological-functional analogies. Here we constrain the diets of 17 pterosaur genera by applying dental microwear texture analysis to the three-dimensional sub-micrometre scale tooth textures that formed during food consumption. We reveal broad patterns of dietary diversity (e.g. Dimorphodon as a vertebrate consumer; Austriadactylus as a consumer of \u2018hard\u2019 invertebrates) and direct evidence of sympatric niche partitioning (Rhamphorhynchus as a piscivore; Pterodactylus as a generalist invertebrate consumer). We propose that the ancestral pterosaur diet was dominated by invertebrates and later pterosaurs evolved into piscivores and carnivores, shifts that might reflect ecological displacements due to pterosaur-bird competition.", "keyphrases": ["vertebrate", "pterosaur", "dietary diversity"]}
{"id": "10.1126/science.1253451", "title": "Whole-genome analyses resolve early branches in the tree of life of modern birds", "abstract": "To better determine the history of modern birds, we performed a genome-scale phylogenetic analysis of 48 species representing all orders of Neoaves using phylogenomic methods created to handle genome-scale data. We recovered a highly resolved tree that confirms previously controversial sister or close relationships. We identified the first divergence in Neoaves, two groups we named Passerea and Columbea, representing independent lineages of diverse and convergently evolved land and water bird species. Among Passerea, we infer the common ancestor of core landbirds to have been an apex predator and confirm independent gains of vocal learning. Among Columbea, we identify pigeons and flamingoes as belonging to sister clades. Even with whole genomes, some of the earliest branches in Neoaves proved challenging to resolve, which was best explained by massive protein-coding sequence convergence and high levels of incomplete lineage sorting that occurred during a rapid radiation after the Cretaceous-Paleogene mass extinction event about 66 million years ago.", "keyphrases": ["early branch", "modern bird", "sister"]}
{"id": "paleo.010608", "title": "Estimating Impact Forces of Tail Club Strikes by Ankylosaurid Dinosaurs", "abstract": "Background It has been assumed that the unusual tail club of ankylosaurid dinosaurs was used actively as a weapon, but the biological feasibility of this behaviour has not been examined in detail. Ankylosaurid tail clubs are composed of interlocking vertebrae, which form the handle, and large terminal osteoderms, which form the knob. Methodology/Principal Findings Computed tomographic (CT) scans of several ankylosaurid tail clubs referred to Dyoplosaurus and Euoplocephalus, combined with measurements of free caudal vertebrae, provide information used to estimate the impact force of tail clubs of various sizes. Ankylosaurid tails are modeled as a series of segments for which mass, muscle cross-sectional area, torque, and angular acceleration are calculated. Free caudal vertebrae segments had limited vertical flexibility, but the tail could have swung through approximately 100\u00b0 laterally. Muscle scars on the pelvis record the presence of a large M. longissimus caudae, and ossified tendons alongside the handle represent M. spinalis. CT scans showed that knob osteoderms were predominantly cancellous, which would have lowered the rotational inertia of the tail club and made it easier to wield as a weapon. Conclusions/Significance Large knobs could generate sufficient force to break bone during impacts, but average and small knobs could not. Tail swinging behaviour is feasible in ankylosaurids, but it remains unknown whether the tail was used for interspecific defense, intraspecific combat, or both.", "keyphrases": ["impact force", "tail club", "ankylosaurid dinosaur", "weapon", "theropod"]}
{"id": "10.1371/journal.pone.0257041", "title": "Adaptive capacity and flexibility of the Neanderthals at Heidenschmiede (Swabian Jura) with regard to core reduction strategies", "abstract": "The branched reduction system at the Heidenschmiede described here is hitherto exceptional for the Middle Paleolithic of the Swabian Jura. By means of refits and supporting objects, we are able to describe a superordinate reduction system that combines several individual reduction concepts, such as Levallois and blade production, within one volume. In the Middle Paleolithic of the Swabian Jura, blade technology has thus far played a rather minor role. On the one hand, it is possible to split a selected volume (nodule) into three parts, which are reduced separately according to individual concepts. On the other hand, it is also possible to reduce parts of a volume with one concept first and then with another. The hypothetical reduction system can be branched or linear, thus emphasizing the technological flexibility in core reduction, which requires a high degree of cognitive skills of three-dimensional imagination.", "keyphrases": ["flexibility", "heidenschmiede", "swabian jura"]}
{"id": "paleo.009207", "title": "Convergent Evolution in Aquatic Tetrapods: Insights from an Exceptional Fossil Mosasaur", "abstract": "Mosasaurs (family Mosasauridae) are a diverse group of secondarily aquatic lizards that radiated into marine environments during the Late Cretaceous (98\u201365 million years ago). For the most part, they have been considered to be simple anguilliform swimmers \u2013 i.e., their propulsive force was generated by means of lateral undulations incorporating the greater part of the body \u2013 with unremarkable, dorsoventrally narrow tails and long, lizard-like bodies. Convergence with the specialized fusiform body shape and inferred carangiform locomotory style (in which only a portion of the posterior body participates in the thrust-producing flexure) of ichthyosaurs and metriorhynchid crocodyliform reptiles, along with cetaceans, has so far only been recognized in Plotosaurus, the most highly derived member of the Mosasauridae. Here we report on an exceptionally complete specimen (LACM 128319) of the moderately derived genus Platecarpus that preserves soft tissues and anatomical details (e.g., large portions of integument, a partial body outline, putative skin color markings, a downturned tail, branching bronchial tubes, and probable visceral traces) to an extent that has never been seen previously in any mosasaur. Our study demonstrates that a streamlined body plan and crescent-shaped caudal fin were already well established in Platecarpus, a taxon that preceded Plotosaurus by 20 million years. These new data expand our understanding of convergent evolution among marine reptiles, and provide insights into their evolution's tempo and mode.", "keyphrases": ["aquatic tetrapod", "mosasaur", "ichthyosaur", "cetacean", "convergent evolution"]}
{"id": "paleo.008589", "title": "The fossil record of lissamphibians from Africa, Madagascar, and the Arabian Plate", "abstract": "Lissamphibians (frogs, salamanders, caecilians, and the extinct Albanerpetontidae) have a near global distribution. Africa, its associated islands (especially Madagascar and the Seychelles) and the Arabian Plate are home to about 27 families (including 15 endemic) and 1135 species of extant lissamphibians or about 38 and 15 %, respectively, of the global totals. The region also contains an extensive, but patchy and somewhat under-appreciated fossil record. Based on published and unpublished information, we provide here the most comprehensive review to date of the lissamphibian fossil record from the region. We also discuss the insights those occurrences provide into past distributions and diversities of lissamphibians in the region and the establishment of the modern fauna. Our review relies on occurrence data from 93 sets of localities of basal Triassic through Holocene age, distributed across 23 countries. As with the modern lissamphibian fauna of the region, the fossil record is dominated by frogs, but there also are notable occurrences of other lissamphibians, including several genera of enigmatic Cretaceous salamanders, one of two known stem caecilians, and the only Gondwanan records for albanerpetontids. Africa is one of only two continents (the other being North America) to have occurrences for all four lissamphibian clades. Twenty named and currently accepted fossil lissamphibian species are recognised from the region: one stem and 14 crown frogs (11 or possibly 12 of which are pipimorphs, 1 alytid, and 1 neobatrachian possibly referable to the otherwise exclusively South American families Ceratophryidae or Calyptocephalellidae); three salamanders; one stem caecilian; and one albanerpetontid. Additional and as yet unnamed taxa are represented in existing collections, and others undoubtedly remain to be discovered. Of the 27 extant lissamphibian families currently recognised from the region, 12 of 22 frog families (including five endemics: Brevicipitidae, Heleophrynidae, Hyperoliidae, Ptychadenidae, and Pyxicephalidae) and the sole salamander family (Salamandridae) have fossil records; at present, none of the known caecilian fossils can be assigned with confidence to any of the four extant families currently recognised in the region. The biogeographic histories of lissamphibians in Africa, its associated islands and the Arabian Plate are characterised by vicariant and dispersal events related to the complex palaeogeographic history of the region.", "keyphrases": ["lissamphibian", "madagascar", "arabian plate", "albanerpetontidae", "fossil specimen"]}
{"id": "10.1111/j.1475-4983.2011.01090.x", "title": "The Rhaetian flora of R\u00f6gla, northern Scania, Sweden", "abstract": "Abstract:\u2002 R\u00f6gla is the northernmost locality yielding Mesozoic plant fossils in Scania, southern Sweden, and is one of the northernmost Rhaetian assemblages in Europe. The assemblage consists of over 500 specimens collected 50\u201360\u2003years ago, of which 139 yielded identifiable plant remains referable to 15 plant species; another 19 specimens are tentatively assigned to four species because of their fragmentary preservation. The flora includes sphenophytes, ferns, cycads, bennettitaleans, seed ferns of uncertain alliance, conifers and some leaf remains that are tentatively assigned to ginkgophytes based on their epidermal anatomy. The species\u2010level composition of the assemblage is consistent with a Rhaetian age and is similar to well\u2010known floras from nearby H\u00f6gan\u00e4s and Bjuv, except for the absence of cycads belonging to Nilssonia, which are very common in most other Scanian floras. The fossil assemblage is interpreted to derive from multi\u2010storey vegetation occupying moist habitats on a coastal plain. Strong affinities are evident with the coeval floras of Jameson Land, Greenland, reinforcing the concept of a distinctive North Atlantic floristic sub\u2010province at the close of the Triassic.", "keyphrases": ["flora", "r\u00f6gla", "sweden"]}
{"id": "paleo.010767", "title": "Regional Environmental Breadth Predicts Geographic Range and Longevity in Fossil Marine Genera", "abstract": "Background Geographic range is a good indicator of extinction susceptibility in fossil marine species and higher taxa. The widely-recognized positive correlation between geographic range and taxonomic duration is typically attributed to either accumulating geographic range with age or an extinction buffering effect, whereby cosmopolitan taxa persist longer because they are reintroduced by dispersal from remote source populations after local extinction. The former hypothesis predicts that all taxa within a region should have equal probabilities of extinction regardless of global distributions while the latter predicts that cosmopolitan genera will have greater survivorship within a region than endemics within the same region. Here we test the assumption that all taxa within a region have equal likelihoods of extinction. Methodology/Principal Findings We use North American and European occurrences of marine genera from the Paleobiology Database and the areal extent of marine sedimentary cover in North America to show that endemic and cosmopolitan fossil marine genera have significantly different range-duration relationships and that broad geographic range and longevity are both predicted by regional environmental breadth. Specifically, genera that occur outside of the focal region are significantly longer lived and have larger geographic ranges and environmental breadths within the focal region than do their endemic counterparts, even after controlling for differences in sampling intensity. Analyses of the number of paleoenvironmental zones occupied by endemic and cosmopolitan genera suggest that the number of paleoenvironmental zones occupied is a key factor of geographic range that promotes genus survivorship. Conclusions/Significance Wide environmental tolerances within a single region predict both broad geographic range and increased longevity in marine genera over evolutionary time. This result provides a specific driving mechanism for the spatial and temporal distributions of marine genera at regional and global scales and is consistent with the niche-breadth hypothesis operating on macroevolutionary timescales.", "keyphrases": ["longevity", "fossil marine genera", "extent"]}
{"id": "10.1029/2011PA002211", "title": "North Atlantic ventilation of \"southern-sourced\" deep water in the glacial ocean", "abstract": "One potential mechanism for lowering atmospheric CO2 during glacial times is an increase in the fraction of the global ocean ventilated by the North Atlantic, which produces deep water with a low concentration of unused nutrients and thus drives the ocean's biological pump to a high efficiency. However, the data indicate that during glacial times, a water mass low in 13C/12C and 14C/C occupied the deep Atlantic, apparently at the expense of North Atlantic Deep Water (NADW). This water is commonly referred to as \u201csouthern-sourced\u201d because of its apparent entry into the Atlantic basin from the South, prompting the inference that it was ventilated at the Southern Ocean surface. Here, we propose that this deep Atlantic water mass actually included a large fraction of North Atlantic-ventilated water, the chemical characteristics of which were altered by recirculation in the deep Southern and Indo-Pacific oceans. In an ocean model sensitivity experiment that reduces Antarctic Bottom Water formation and weakens its overturning circulation, we find that a much greater fraction of NADW is transported into the Southern Ocean without contacting the surface and is entrained and mixed into the southern-sourced deep water that spreads into the global abyssal ocean. Thus, North Atlantic ventilation takes over more of the ocean interior, lowering atmospheric CO2, and yet the abyssal Atlantic is filled from the South with old water low in 13C/12C and 14C/C, consistent with glacial data.", "keyphrases": ["deep water", "ocean", "nutrient", "north atlantic ventilation"]}
{"id": "10.1130/G35615.1", "title": "Thresholds for Paleozoic ice sheet initiation", "abstract": "Continental drift and atmospheric greenhouse gas concentrations have each, in turn, been proposed to explain the evolution of Paleozoic climate from early era ice-free conditions to late era continental-scale glaciation, despite continually increasing solar luminosity. To assess the relative roles of continental configuration and atmospheric p CO 2 on the formation of continental-scale ice sheets, we use a coupled ice sheet\u2013climate model to simulate ice sheet initiation at eight different Paleozoic time slices using uniform topography. For each time slice, we simulate the climate at three atmospheric pCO 2 levels (560, 840, and 1120 ppm) and both constant (97.5% of modern) and time-appropriate solar luminosity values. Under constant luminosity, our results indicate that continental configurations favor ice sheet initiation in the mid-Paleozoic (400\u2013340 Ma). After accounting for solar brightening, ice sheet initiation is favored in the early Paleozoic (480\u2013370 Ma) simulations. Neither of these results is consistent with geological evidence of continental-scale glaciation. Changes in atmospheric pCO 2 can reconcile these differences. Sufficiently high ( \u22651120 ppm) or low (\u2264560 ppm) pCO 2 overcomes paleogeographic and luminosity predispositions to ice-free or ice age conditions. Based on our simulations and geological evidence of glaciation and atmospheric composition, we conclude that atmospheric pCO 2 was the primary control on Paleozoic continental-scale glaciation, while paleogeographic configurations and solar irradiance were of secondary importance.", "keyphrases": ["glacial episode", "greenhouse condition", "palaeozoic oscillating climate"]}
{"id": "10.1111/brv.12829", "title": "Morphology and distribution of scales, dermal ossifications, and other non\u2010feather integumentary structures in non\u2010avialan theropod dinosaurs", "abstract": "Modern birds are typified by the presence of feathers, complex evolutionary innovations that were already widespread in the group of theropod dinosaurs (Maniraptoriformes) that include crown Aves. Squamous or scaly reptilian\u2010like skin is, however, considered the plesiomorphic condition for theropods and dinosaurs more broadly. Here, we review the morphology and distribution of non\u2010feathered integumentary structures in non\u2010avialan theropods, covering squamous skin and naked skin as well as dermal ossifications. The integumentary record of non\u2010averostran theropods is limited to tracks, which ubiquitously show a covering of tiny reticulate scales on the plantar surface of the pes. This is consistent also with younger averostran body fossils, which confirm an arthral arrangement of the digital pads. Among averostrans, squamous skin is confirmed in Ceratosauria (Carnotaurus), Allosauroidea (Allosaurus, Concavenator, Lourinhanosaurus), Compsognathidae (Juravenator), and Tyrannosauroidea (Santanaraptor, Albertosaurus, Daspletosaurus, Gorgosaurus, Tarbosaurus, Tyrannosaurus), whereas dermal ossifications consisting of sagittate and mosaic osteoderms are restricted to Ceratosaurus. Naked, non\u2010scale bearing skin is found in the contentious tetanuran Sciurumimus, ornithomimosaurians (Ornithomimus) and possibly tyrannosauroids (Santanaraptor), and also on the patagia of scansoriopterygids (Ambopteryx, Yi). Scales are surprisingly conservative among non\u2010avialan theropods compared to some dinosaurian groups (e.g. hadrosaurids); however, the limited preservation of tegument on most specimens hinders further interrogation. Scale patterns vary among and/or within body regions in Carnotaurus, Concavenator and Juravenator, and include polarised, snake\u2010like ventral scales on the tail of the latter two genera. Unusual but more uniformly distributed patterning also occurs in Tyrannosaurus, whereas feature scales are present only in Albertosaurus and Carnotaurus. Few theropods currently show compelling evidence for the co\u2010occurrence of scales and feathers (e.g. Juravenator, Sinornithosaurus), although reticulate scales were probably retained on the mani and pedes of many theropods with a heavy plumage. Feathers and filamentous structures appear to have replaced widespread scaly integuments in maniraptorans. Theropod skin, and that of dinosaurs more broadly, remains a virtually untapped area of study and the appropriation of commonly used techniques in other palaeontological fields to the study of skin holds great promise for future insights into the biology, taphonomy and relationships of these extinct animals.", "keyphrases": ["dermal ossification", "integumentary structure", "theropod dinosaur", "skin"]}
{"id": "paleo.000510", "title": "A new genus and species of thorny lacewing from Upper Cretaceous Kuji amber, northeastern Japan (Neuroptera, Rhachiberothidae)", "abstract": "Abstract Kujiberothateruyukiigen. et sp. n., a remarkable new genus and species of Rhachiberothidae, is described from Upper Cretaceous amber from the Kuji area in northeastern Japan. This discovery represents the first record of this family both from Japan and from East Asia. This fossil taxon has the largest foreleg in the subfamily Paraberothinae found to date and its discovery implies that this group had higher morphological diversity in the Cretaceous than it does now. This finding also stresses the importance of the insect inclusions in Kuji amber, which have not been well explored in spite of their potential abundance.", "keyphrases": ["new genus", "northeastern japan", "rhachiberothidae"]}
{"id": "10.2517/2019PR005", "title": "Madygella Humioi sp. nov. from the Upper Triassic Mine Group, Southwest Japan: The Oldest Record of a Sawfly (Hymenoptera: Symphyta) in East Asia", "abstract": "Abstract. A primitive sawfly, Madygella humioi sp. nov., belonging to the family Xyelidae (Hymenoptera: Symphyta), is newly described from the Upper Triassic Mine Group, Yamaguchi Prefecture, southwest Japan. The new species differs from the five previously known Madygella species in having a cell length of 1r plus 2r shorter than that of 3r + 4r and a cell height of 3r + 4r lower than 2r plus pterostigma in a forewing. To date, this is the oldest fossil record of sawflies in East Asia. Regarding genus Madygella, this is the first example found outside of the Kyrgyz Republic. This discovery provides an insight into the early evolution of the order Hymenoptera and suggests a widespread distribution of the pioneering genus Madygella during the Triassic period.", "keyphrases": ["southwest japan", "sawfly", "hymenoptera"]}
{"id": "paleo.006669", "title": "The record of Aplodontidae (Rodentia, Mammalia) in the Oligocene and Miocene of the Valley of Lakes (Central Mongolia) with some comments on the morphologic variability", "abstract": "The present publication reports new discoveries of Oligocene and early Miocene aplodontid rodents from the Taatsiin Gol area (Valley of Lakes) in Mongolia. The fossil aplodontids recovered in this area are mainly composed of dental remains, some fragmentary jaws plus one partially preserved skull. Aplodontid rodents have been found from the early Oligocene (local biozone A) to the early middle Miocene (local biozone D). Altogether, eight taxa belonging to five genera have been identified in the investigated deposits: Ninamys arboraptus, Ninamys kazimierzi, Promeniscomys cf. sinensis, Prosciurus? mongoliensis and Prosciurus? sp. nov. in the early Oligocene; N. arboraptus, Proansomys badamae sp. nov. and Ansomyinae indet. in the late Oligocene; and Ansomys sp.1 in the early Miocene. In addition, although outside of the topic of the present special issue, one additional taxon, Ansomys sp.2, is reported from the ?middle Miocene. The material of aplodontids is usually relatively scarce in Asian localities. For the first time, with a sample size of 81 specimens, the material from Central Mongolia (mainly from the Oligocene) now allows a more accurate description of the morphological and size variability and resolves some systematic problems. The study of these aplodontids reveals that they are more abundant and diverse in the early Oligocene and that the diversity decreases during the late Oligocene and Miocene. One hypothesis, to explain the opposite diversity trend observed previously for sciurids in the same region, is that both Sciuromorpha families might have competed for the same resources from the early Oligocene to the middle Miocene in Central Mongolia.", "keyphrases": ["miocene", "lakes", "central mongolia"]}
{"id": "paleo.008147", "title": "A large hyaenodont from the Lutetian of Switzerland expands the body mass range of the European mammalian predators during the Eocene", "abstract": "We here present a new hyaenodont genus and species from the Lutetian locality of Egerkingen \u03b3 (Switzerland; MP13?): Cartierodon egerkingensis gen. et sp. nov. The new taxon is represented by numerous dental elements, mostly isolated teeth. The molars show typical features of a hypercarnivorous predator such as the strong reduction of the crushing (talonid/protocone) and puncturing (metaconid) structures. The calculation of several dental indices indicates that this hyaenodont may have been a bone-cracking predator. The new taxon differs from all the hyaenodonts previously known in Europe during the Ypresian and Lutetian by its larger size, with an estimated mass of almost 29 kg (the size of the extant African wild dog, Lycaon pictus ). Other hyaenodonts known for this period do not exceed 20 kg. Previous authors proposed the hypothesis of an ecological limitation of the body mass, but the description of Cartierodon egerkingensis indicates instead that the European hyaenodonts continuously increased in size throughout the Eocene. We also performed a phylogenetic analysis in order to test the relationships of this new taxon: the new hyaenodont appears to be closely related to the Lutetian hyaenodont Prodissopsalis eocaenicus .", "keyphrases": ["hyaenodont", "predator", "eocene"]}
{"id": "10.5194/gmd-12-3149-2019", "title": "The DeepMIP contribution to PMIP4: methodologies for selection, compilation and analysis of latest Paleocene and early Eocene climate proxy data, incorporating version 0.1 of the DeepMIP database", "abstract": "Abstract. The early Eocene (56 to 48 million years ago) is inferred to have\nbeen the most recent time that Earth's atmospheric CO2 concentrations\nexceeded 1000\u2009ppm. Global mean temperatures were also substantially warmer\nthan those of the present day. As such, the study of early Eocene climate provides insight\ninto how a super-warm Earth system behaves and offers an opportunity to\nevaluate climate models under conditions of high greenhouse gas forcing. The\nDeep Time Model Intercomparison Project (DeepMIP) is a systematic\nmodel\u2013model and model\u2013data intercomparison of three early Paleogene time\nslices: latest Paleocene, Paleocene\u2013Eocene thermal maximum (PETM) and early\nEocene climatic optimum (EECO). A previous article outlined the model\nexperimental design for climate model simulations. In this article, we\noutline the methodologies to be used for the compilation and analysis of\nclimate proxy data, primarily proxies for temperature and CO2. This\npaper establishes the protocols for a concerted and coordinated effort to\ncompile the climate proxy records across a wide geographic range. The\nresulting climate \u201catlas\u201d will be used to constrain and evaluate climate\nmodels for the three selected time intervals and provide insights into the\nmechanisms that control these warm climate states. We provide version 0.1 of\nthis database, in anticipation that this will be expanded in subsequent\npublications.\n", "keyphrases": ["deepmip", "methodology", "paleocene", "climate proxy data", "petm"]}
{"id": "10.1163/9789004210714_014", "title": "A new technique for preparation of small-sized amber samples with application to mites", "abstract": "Small preparations are necessary to receive high-resolution morphological data on minute amber inclusions, like mites, tiny insects, pollen, and fungi. For mites, observations from four to six sides are often necessary for an accurate identification and systematic description. The main difficulty of such preparation is that human hand is not precise enough for holding and manipulating minute objects. This chapter describes tools and protocol for routine preparation of voluminous amber samples of submillimeter size, including artificial resin embedding after vacuum treatment, trimming, grinding, and preparation for light microscopy under immersion oil. A review of received results in paleontology of amber mite inclusions is provided along with a discussion on the conservation problems raised by small size of pieces. Keywords:amber samples; fossil mites; light microscopy", "keyphrases": ["preparation", "amber sample", "mite"]}
{"id": "10.2113/gsrocky.46.2.165", "title": "Stratigraphic revision of the Green River Formation in Fossil Basin, WyomingOverfilled to underfilled lake evolution", "abstract": "The Eocene Green River Formation in Fossil Basin, Wyoming provides a detailed record of the paleoecology and depositional history of ancient Fossil Lake. Fossil Lake was one of three Eocene lakes that formed an extensive lake system in Wyoming, Utah, and Colorado. It began as a flood-plain lake in the southern part of Fossil Basin and expanded northward as the lake evolved. Fossil Lake went through the major stages of lake evolution, including the overfilled (Road Hollow Member), balanced-fill (Fossil Butte Member), and underfilled (Angelo Member) stages. These stages are represented in the sedimentary record by a complete suite of lake-margin to lake-center facies. This study establishes the Road Hollow Member of the Green River Formation as representing the earliest stage of lake evolution in Fossil Lake. We also revise the boundaries for the Fossil Butte and Angelo Members of the Green River Formation, which clearly delineate the latest two stages of lake evolution. These revisions not only describe and add a previously unrecognized and thick sequence of lacustrine rocks in Fossil Basin, but help us to better understand the depositional systems that existed during each stage of lake evolution.", "keyphrases": ["green river formation", "fossil basin", "lake"]}
{"id": "10.1080/02724634.2021.1901730", "title": "Panzhousaurus rotundirostris Jiang et al., 2019 (Diapsida: Sauropterygia) and the Recovery of the Monophyly of Pachypleurosauridae", "abstract": "ABSTRACT Panzhousaurus rotundirostris Jiang, Lin, Rieppel, Motani and Sun, 2019, is restudied on the basis of a second specimen from the Upper Member of the Guanling Formation near Panzhou City, Guizhou Province, China. The second specimen offers hitherto unknown or unconfirmed information regarding the dermal palate, the ventral aspect of the cervical vertebrae, and the hind limbs, thus permitting a refinement of the diagnosis. Newly added or modified diagnostic characters include paired frontals with no posterolateral process, elongated and slender phalanges in the manus and pes, and a phalangeal formula of 3-4-5-4-3 for the manus, and 2-3-4-5-3 for the pes. A new phylogenetic analysis of Eosauropterygia demonstrates that Pachypleurosauridae is the sister taxon of Eusauropterygia, and the monophyly of these groups as traditionally upheld is confirmed. Panzhousaurus is most closely related to Dianopachysaurus and Keichousaurus within Pachypleurosauridae. In this study, the monophyletic Pistosauroidea excludes Corosaurus and Cymatosaurus. The latter two genera are found to form a monophyletic clade that represents the basal-most members of Eusauropterygia, which is in accordance with their stratigraphic distribution.", "keyphrases": ["monophyly", "eusauropterygia", "dianopachysaurus", "pachypleurosaur", "panzhousaurus"]}
{"id": "10.1073/pnas.1521478113", "title": "Dinosaurs in decline tens of millions of years before their final extinction", "abstract": "Significance Whether dinosaurs were in decline before their final extinction 66 Mya has been debated for decades with no clear resolution. This dispute has not been resolved because of inappropriate data and methods. Here, for the first time to our knowledge, we apply a statistical approach that models changes in speciation and extinction through time. We find overwhelming support for a long-term decline across all dinosaurs and within all three major dinosaur groups. Our results highlight that dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event 66 Mya. Whether dinosaurs were in a long-term decline or whether they were reigning strong right up to their final disappearance at the Cretaceous\u2013Paleogene (K-Pg) mass extinction event 66 Mya has been debated for decades with no clear resolution. The dispute has continued unresolved because of a lack of statistical rigor and appropriate evolutionary framework. Here, for the first time to our knowledge, we apply a Bayesian phylogenetic approach to model the evolutionary dynamics of speciation and extinction through time in Mesozoic dinosaurs, properly taking account of previously ignored statistical violations. We find overwhelming support for a long-term decline across all dinosaurs and within all three dinosaurian subclades (Ornithischia, Sauropodomorpha, and Theropoda), where speciation rate slowed down through time and was ultimately exceeded by extinction rate tens of millions of years before the K-Pg boundary. The only exceptions to this general pattern are the morphologically specialized herbivores, the Hadrosauriformes and Ceratopsidae, which show rapid species proliferations throughout the Late Cretaceous instead. Our results highlight that, despite some heterogeneity in speciation dynamics, dinosaurs showed a marked reduction in their ability to replace extinct species with new ones, making them vulnerable to extinction and unable to respond quickly to and recover from the final catastrophic event.", "keyphrases": ["million", "final extinction", "long-term decline"]}
{"id": "10.1073/pnas.1324002111", "title": "Tectonic-driven climate change and the diversification of angiosperms", "abstract": "Significance Angiosperm range expansion and diversification have been major biotic upheavals in the Earth history. Mechanisms involved in their successful diversification have mainly called upon intrinsic processes at the plant level, leaving the influence of the global tectonics poorly explored. We investigate evolution of paleogeography and climate and correlate it with the diversification of angiosperms by using a general circulation model. We show that Pangea breakup induced an important expansion of temperate zones during the late Cretaceous which was concomitant to the rise of angiosperms. We suggest that the breakup of Pangea led to the onset of new humid bioclimatic continents, which in turn may have provided new external conditions for ecological expansion of the angiosperms and their diversification. In 1879, Charles Darwin characterized the sudden and unexplained rise of angiosperms during the Cretaceous as an \u201cabominable mystery.\u201d The diversification of this clade marked the beginning of a rapid transition among Mesozoic ecosystems and floras formerly dominated by ferns, conifers, and cycads. Although the role of environmental factors has been suggested [Coiffard C, G\u00f3mez B (2012) Geol Acta 10(2):181\u2013188], Cretaceous global climate change has barely been considered as a contributor to angiosperm radiation, and focus was put on biotic factors to explain this transition. Here we use a fully coupled climate model driven by Mesozoic paleogeographic maps to quantify and discuss the impact of continental drift on angiosperm expansion and diversification. We show that the decrease of desertic belts between the Triassic and the Cretaceous and the subsequent onset of long-lasting humid conditions during the Late Cretaceous were driven by the breakup of Pangea and were contemporaneous with the first rise of angiosperm diversification. Positioning angiosperm-bearing fossil sites on our paleobioclimatic maps shows a strong match between the location of fossil-rich outcrops and temperate humid zones, indicating that climate change from arid to temperate dominance may have set the stage for the ecological expansion of flowering plants.", "keyphrases": ["climate change", "diversification", "angiosperm"]}
{"id": "paleo.009413", "title": "Long-distance connections in the Copper Age: New evidence from the Alpine Iceman\u2019s copper axe", "abstract": "25 years after the discovery in the \u00d6tztal Italian Alps, the 5,300-year-old mummy keeps providing key information on human biological and medical conditions, aspects of everyday life and societal organization in the Copper Age. The hand axe found with the body of the Alpine Iceman is one of the rare copper objects that is firmly dated to the early Copper Age because of the radiocarbon dating of the axe wooden shaft. Here we report the measurement of the lead isotope ratios of the copper blade. The results unambiguously indicate that the source of the metal is the ore-rich area of Southern Tuscany, despite ample evidence that Alpine copper ore sources were known and exploited at the time. The experimental results are discussed within the framework of all the available coeval archaeometallurgical data in Central-Southern Europe: they show that the Alps were a neat cultural barrier separating distinct metal circuits. The direct evidence of raw metal or object movement between Central Italy and the Alps is surprising and provides a new perspective on long-distance relocation of goods and relationships between the early Copper Age cultures in the area. The result is in line with the recent investigations re-evaluating the timing and extent of copper production in Central Italy in the 4th millennium BC.", "keyphrases": ["copper age", "alpine iceman", "central italy"]}
{"id": "10.1073/pnas.1904260116", "title": "Radiokrypton unveils dual moisture sources of a deep desert aquifer", "abstract": "Significance Paleoprecipitation records and subsurface water storage properties are essential data ingredients for accurate hydroclimate and water balance projections. Although both types of data could be extracted from groundwater, their application over long timescales had been limited by the lack of appropriate chronometers. We used a long-lived radiokrypton isotope and identified two distinct moisture source contributions to a deep desert aquifer from low eccentricity periods, one recent and the other 360 ky ago. The groundwater recharge periods show the sensitivity of the moisture transport processes to orbital forcing, whereas the long storage reflects subsurface flow attenuation exerted by faults. Krypton-81 enables groundwater to serve as a direct record of paleoprecipitation over land and of subsurface water storage for the past 1,300 ky. In arid regions, groundwater is a vital resource that can also provide a long-term record of the regional water cycle. However, the use of groundwater as a paleoclimate proxy has been limited by the complex hydrology and the lack of appropriate chronometers to determine the recharge time without complication. Applying 81Kr, a long-lived radioisotope tracer, we investigate the paleohydroclimate and subsurface water storage properties of the Nubian Sandstone Aquifer in the Negev Desert, Israel. Based on the spatial distributions of stable isotopes and the abundance of 81Kr, we resolve subsurface mixing and identify two distinct moisture sources of the recharge: one recent (<38 ky ago) from the Mediterranean and the other 361 \u00b1 30 ky ago from the tropical Atlantic, both of which occurred under conditions of low orbital eccentricity comparable to that of the present. The recent recharge provided by the moisture from Mediterranean cyclones can be attributed to the southward shift of the storm track during the Last Glacial Maximum, and the earlier recharge can be attributed to moisture from the Atlantic delivered as tropical plumes under a climate colder than the present. Furthermore, the residence time of the latter reveals that tectonically active terrain can store groundwater for an unexpectedly long period, likely due to strongly attenuated groundwater flow across the fault zones. With this tracer, groundwater can now serve as a direct record of paleoprecipitation over land and of subsurface water storage from the mid-Pleistocene and onward.", "keyphrases": ["moisture source", "deep desert", "groundwater"]}
{"id": "paleo.011956", "title": "A New Baurusuchid (Crocodyliformes, Mesoeucrocodylia) from the Late Cretaceous of Brazil and the Phylogeny of Baurusuchidae", "abstract": "Background Baurusuchidae is a group of extinct Crocodyliformes with peculiar, dog-faced skulls, hypertrophied canines, and terrestrial, cursorial limb morphologies. Their importance for crocodyliform evolution and biogeography is widely recognized, and many new taxa have been recently described. In most phylogenetic analyses of Mesoeucrocodylia, the entire clade is represented only by Baurusuchus pachecoi, and no work has attempted to study the internal relationships of the group or diagnose the clade and its members. Methodology/Principal Findings Based on a nearly complete skull and a referred partial skull and lower jaw, we describe a new baurusuchid from the Vale do Rio do Peixe Formation (Bauru Group), Late Cretaceous of Brazil. The taxon is diagnosed by a suite of characters that include: four maxillary teeth, supratemporal fenestra with equally developed medial and anterior rims, four laterally visible quadrate fenestrae, lateral Eustachian foramina larger than medial Eustachian foramen, deep depression on the dorsal surface of pterygoid wing. The new taxon was compared to all other baurusuchids and their internal relationships were examined based on the maximum parsimony analysis of a discrete morphological data matrix. Conclusion The monophyly of Baurusuchidae is supported by a large number of unique characters implying an equally large morphological gap between the clade and its immediate outgroups. A complex phylogeny of baurusuchids was recovered. The internal branch pattern suggests two main lineages, one with a relatively broad geographical range between Argentina and Brazil (Pissarrachampsinae), which includes the new taxon, and an endemic clade of the Bauru Group in Brazil (Baurusuchinae).", "keyphrases": ["new baurusuchid", "crocodyliformes", "phylogeny", "skull"]}
{"id": "paleo.001770", "title": "First levantine fossil murines shed new light on the earliest intercontinental dispersal of mice", "abstract": "Recent extensive field prospecting conducted in the Upper Miocene of Lebanon resulted in the discovery of several new fossiliferous localities. One of these, situated in the Zahleh area (Bekaa Valley, central Lebanon) has yielded a particularly diverse vertebrate fauna. Micromammals constitute an important part of this assemblage because not only do they represent the first Neogene rodents and insectivores from Lebanon, but they are also the only ones from the early Late Miocene of the Arabian Peninsula and circumambient areas. Analyses of the murines from Zahleh reveal that they belong to a small-sized early Progonomys, which cannot be assigned to any of the species of the genus hitherto described. They are, thereby, shown to represent a new species: Progonomys manolo. Morphometric analyses of the outline of the first upper molars of this species suggest a generalist and omnivorous diet. This record sheds new light onto a major phenomenon in the evolutionary history of rodents, which is the earliest dispersal of mice. It suggests that the arrival of murines in Africa got under way through the Levant rather than via southern Europe and was monitored by the ecological requirements of Progonomys.", "keyphrases": ["new light", "dispersal", "mouse"]}
{"id": "10.1017/S1755691017000329", "title": "Earwigs (Dermaptera) from the Mesozoic of England and Australia, described from isolated tegmina, including the first species to be named from the Triassic", "abstract": "ABSTRACT Dermaptera (earwigs) are described from the Triassic of Australia and England, and from the Jurassic and Cretaceous of England. Phanerogramma heeri (Giebel) is transferred from Coleoptera and it and Brevicula gradus Whalley are re-described. Seven new taxa are named based on tegmina: Phanerogramma australis sp. nov. and P. dunstani sp. nov. from the Late Triassic of Australia; P. gouldsbroughi sp. nov. from the Triassic/Jurassic of England; Brevicula maculata sp. nov. and Trivenapteron moorei gen. et sp. nov. from the Early Jurassic of England; and Dimapteron corami gen et sp. nov. and Valdopteron woodi gen. et sp. nov. from the Early Cretaceous of England. Phanerogramma, Dimapteron and Valdopteron are tentatively placed in the family Dermapteridae, and Trivenapteron is incertae sedis. Most of the specimens of Phanerogramma heeri are from the Brodie Collection and labelled \u2018Lower Lias'; however, some were collected from the underlying Penarth Group, thus this species spans the Triassic/Jurassic boundary. The palaeobiogeography of the Late Triassic and Early Jurassic of England is discussed.", "keyphrases": ["dermaptera", "tegmina", "earwig"]}
{"id": "paleo.007014", "title": "Fenestrapora (Fenestrata, Bryozoa) from the Middle Devonian of Germany", "abstract": "Two species of the fenestrate genus Fenestrapora Hall, 1885 are described from the Middle Devonian (middle Eifelian-lower Givetian) of the Rhenish Massif, Germany. The species Fenestrapora transcaucasica Morozova and Lavrentjeva, 1998 is known from the Middle Devonian (Eifelian) of Transcaucasia, Azerbaijan, and from the Middle Devonian (Eifelian) of Sauerland, Germany. One species is new: Fenestrapora tuberculata sp. nov. Numerical statistics were tested for species discrimination of the studied material of three Fenestrapora species from the Lower Devonian of Spain and Middle Devonian of Germany. Discrepancies in the taxonomical and numerical assignment of the studied samples are explained by restriction of the involved characters and their affection by environmental conditions.", "keyphrases": ["middle devonian", "fenestrapora", "bryozoan"]}
{"id": "paleo.012536", "title": "Timing the Evolutionary Advent of Cyanobacteria and the Later Great Oxidation Event Using Gene Phylogenies of a Sunscreen", "abstract": "The advent of cyanobacteria, with their invention of oxygenic photosynthesis, and the Great Oxidation Event are arguably among the most important events in the evolutionary history of life on Earth. Oxygen is a significant toxicant to all life, but its accumulation in the atmosphere also enabled the successful development and proliferation of many aerobic organisms, especially metazoans. The currently favored dating of the Great Oxidation Event is based on the geochemical rock record. Similarly, the advent of cyanobacteria is also often drawn from the same estimates because in older rocks paleontological evidence is scarce or has been discredited. Efforts to obtain molecular evolutionary alternatives have offered widely divergent estimates. Our analyses provide a novel means to circumvent these limitations and allow us to estimate the large time gap between the two events. ABSTRACT The biosynthesis of the unique cyanobacterial (oxyphotobacterial) indole-phenolic UVA sunscreen, scytonemin, is coded for in a conserved operon that contains both core metabolic genes and accessory, aromatic amino acid biosynthesis genes dedicated to supplying scytonemin\u2019s precursors. Comparative genomics shows conservation of this operon in many, but not all, cyanobacterial lineages. Phylogenetic analyses of the operon\u2019s aromatic amino acid genes indicate that five of them were recruited into the operon after duplication events of their respective housekeeping cyanobacterial cognates. We combined the fossil record of cyanobacteria and relaxed molecular clock models to obtain multiple estimates of these duplication events, setting a minimum age for the evolutionary advent of scytonemin at 2.1\u2009\u00b1\u20090.3 billion years. The same analyses were used to estimate the advent of cyanobacteria as a group (and thus the appearance of oxygenic photosynthesis), at 3.6\u2009\u00b1\u20090.2 billion years before present. Post hoc interpretation of 16S rRNA-based Bayesian analyses was consistent with these estimates. Because of physiological constraints on the use of UVA sunscreens in general, and the biochemical constraints of scytonemin in particular, scytonemin\u2019s age must postdate the time when Earth\u2019s atmosphere turned oxic, known as the Great Oxidation Event (GOE). Indeed, our biological estimate is in agreement with independent geochemical estimates for the GOE. The difference between the estimated ages of oxygenic photosynthesis and the GOE indicates the long span (on the order of a billion years) of the era of \u201coxygen oases,\u201d when oxygen was available locally but not globally. IMPORTANCE The advent of cyanobacteria, with their invention of oxygenic photosynthesis, and the Great Oxidation Event are arguably among the most important events in the evolutionary history of life on Earth. Oxygen is a significant toxicant to all life, but its accumulation in the atmosphere also enabled the successful development and proliferation of many aerobic organisms, especially metazoans. The currently favored dating of the Great Oxidation Event is based on the geochemical rock record. Similarly, the advent of cyanobacteria is also often drawn from the same estimates because in older rocks paleontological evidence is scarce or has been discredited. Efforts to obtain molecular evolutionary alternatives have offered widely divergent estimates. Our analyses provide a novel means to circumvent these limitations and allow us to estimate the large time gap between the two events.", "keyphrases": ["evolutionary advent", "cyanobacteria", "minimum age"]}
{"id": "paleo.010720", "title": "Debris-carrying camouflage among diverse lineages of Cretaceous insects", "abstract": "A diverse insect assemblage of exceptionally preserved debris carriers is reported from Cretaceous Burmese, French, and Lebanese ambers. Insects have evolved diverse methods of camouflage that have played an important role in their evolutionary success. Debris-carrying, a behavior of actively harvesting and carrying exogenous materials, is among the most fascinating and complex behaviors because it requires not only an ability to recognize, collect, and carry materials but also evolutionary adaptations in related morphological characteristics. However, the fossil record of such behavior is extremely scarce, and only a single Mesozoic example from Spanish amber has been recorded; therefore, little is known about the early evolution of this complicated behavior and its underlying anatomy. We report a diverse insect assemblage of exceptionally preserved debris carriers from Cretaceous Burmese, French, and Lebanese ambers, including the earliest known chrysopoid larvae (green lacewings), myrmeleontoid larvae (split-footed lacewings and owlflies), and reduviids (assassin bugs). These ancient insects used a variety of debris material, including insect exoskeletons, sand grains, soil dust, leaf trichomes of gleicheniacean ferns, wood fibers, and other vegetal debris. They convergently evolved their debris-carrying behavior through multiple pathways, which expressed a high degree of evolutionary plasticity. We demonstrate that the behavioral repertoire, which is associated with considerable morphological adaptations, was already widespread among insects by at least the Mid-Cretaceous. Together with the previously known Spanish specimen, these fossils are the oldest direct evidence of camouflaging behavior in the fossil record. Our findings provide a novel insight into early evolution of camouflage in insects and ancient ecological associations among plants and insects.", "keyphrases": ["camouflage", "insect", "amber", "green lacewing", "chrysopidae"]}
{"id": "paleo.009641", "title": "Pathological survey on Temnodontosaurus from the Early Jurassic of southern Germany", "abstract": "Paleopathologies document skeletal damage in extinct organisms and can be used to infer the causes of injury, as well as aspects of related biology, ecology and behavior. To date, few studies have been undertaken on Jurassic marine reptiles, while ichthyosaur pathologies in particular have never been systematically evaluated. Here we survey 41 specimens of the apex predator ichthyosaur Temnodontosaurus from the Early Jurassic of southern Germany in order to document the range and absolute frequency of pathologies observed in this taxon as a function of the number of specimens examined. According to our analysis, most observed pathologies in Temnodontosaurus are force-induced traumas with signs of healing, possibly inflicted during aggressive interactions with conspecifics. When the material is preserved, broken ribs are correlated in most of the cases with traumas elsewhere in the skeleton such as cranial injuries. The range of cranial pathologies in Temnodontosaurus is similar to those reported for extinct cetaceans and mosasaurs, which were interpreted as traces of aggressive encounters. Nevertheless, Temnodontosaurus differs from these other marine amniotes in the absence of pathologies in the vertebral column, consistent with the pattern previously documented in ichthyosaurs. We did not detect any instances of avascular necrosis in Temnodontosaurus from southern Germany, which may reflect a shallow diving life style. This study is intended to provide baseline data for the various types of observed pathologies in large ichthyosaurs occupying the \u2018apex predator\u2019 niche, and potentially clarifies aspects of species-specific behavior relative to other ichthyosaurs and marine amniotes.", "keyphrases": ["temnodontosaurus", "early jurassic", "southern germany", "ichthyosaur", "pathology"]}
{"id": "10.1002/.22599", "title": "Amphibian skull evolution: The developmental and functional context of simplification, bone loss and heterotopy.", "abstract": "Despite their divergent morphology, extant and extinct amphibians share numerous features in the timing and spatial patterning of dermal skull elements. Here, I show how the study of these features leads to a deeper understanding of morphological evolution. Batrachians (salamanders and frogs) have simplified skulls, with dermal bones appearing rudimentary compared with fossil tetrapods, and open cheeks resulting from the absence of other bones. The batrachian skull bones may be derived from those of temnospondyls by truncation of the developmental trajectory. The squamosal, quadratojugal, parietal, prefrontal, parasphenoid, palatine, and pterygoid form rudimentary versions of their homologs in temnospondyls. In addition, failure to ossify and early fusion of bone primordia both result in the absence of further bones that were consistently present in Paleozoic tetrapods. Here, I propose a new hypothesis explaining the observed patterns of bone loss and emargination in a functional context. The starting observation is that jaw-closing muscles are arranged in a different way than in ancestors from the earliest ontogenetic stage onwards, with muscles attaching to the dorsal side of the frontal, parietal, and squamosal. The postparietal and supratemporal start to ossify in a similar way as in branchiosaurids, but are fused to neighboring elements to form continuous attachment areas for the internal adductor. The postfrontal, postorbital, and jugal fail to ossify, as their position is inconsistent with the novel arrangement of adductor muscles. Thus, rearrangement of adductors forms the common theme behind cranial simplification, driven by an evolutionary flattening of the skull in the batrachian stem. J. Exp. Zool. (Mol. Dev. Evol.) 9999B: XX-XX, 2014. \u00a9 2014 Wiley Periodicals, Inc.", "keyphrases": ["functional context", "simplification", "bone loss"]}
{"id": "paleo.000810", "title": "Pigmented anatomy in Carboniferous cyclostomes and the evolution of the vertebrate eye", "abstract": "The success of vertebrates is linked to the evolution of a camera-style eye and sophisticated visual system. In the absence of useful data from fossils, scenarios for evolutionary assembly of the vertebrate eye have been based necessarily on evidence from development, molecular genetics and comparative anatomy in living vertebrates. Unfortunately, steps in the transition from a light-sensitive \u2018eye spot\u2019 in invertebrate chordates to an image-forming camera-style eye in jawed vertebrates are constrained only by hagfish and lampreys (cyclostomes), which are interpreted to reflect either an intermediate or degenerate condition. Here, we report\u2014based on evidence of size, shape, preservation mode and localized occurrence\u2014the presence of melanosomes (pigment-bearing organelles) in fossil cyclostome eyes. Time of flight secondary ion mass spectrometry analyses reveal secondary ions with a relative intensity characteristic of melanin as revealed through principal components analyses. Our data support the hypotheses that extant hagfish eyes are degenerate, not rudimentary, that cyclostomes are monophyletic, and that the ancestral vertebrate had a functional visual system. We also demonstrate integument pigmentation in fossil lampreys, opening up the exciting possibility of investigating colour patterning in Palaeozoic vertebrates. The examples we report add to the record of melanosome preservation in Carboniferous fossils and attest to surprising durability of melanosomes and biomolecular melanin.", "keyphrases": ["cyclostome", "vertebrate eye", "melanosome"]}
{"id": "10.1590/S0036-46652009000300001", "title": "Animal helminths in human archaeological remains: a review of zoonoses in the past.", "abstract": "The authors present a review of records of intestinal parasitic helminths from animals in human archaeological remains, reported since the emergence of paleopathological studies. The objective was to relate paleoparasitological findings to geographic, biotic, and abiotic factors from the environment in which the prehistoric populations lived, and understand some aspects related to the process of human dispersion and biological and cultural evolution. Modification of eating habits and the incorporation of new cultural practices are analyzed from the perspective of zoonoses from prehistory to the present day, especially in Brazilian indigenous populations. Three tables identifying the helminths, their natural hosts, dates, and sites of archaeological findings complete this review. In conclusion, various zoonoses known today have occurred since antiquity, and these data, combined with studies on the emergence and reemergence of diseases, could make possible to compose scenarios for the future.", "keyphrases": ["helminth", "human archaeological remain", "review", "zoonosis"]}
{"id": "10.4202/app.00259.2016", "title": "Earliest True Moth Lacewing from the Middle Jurassic of Inner Mongolia, China", "abstract": "A new moth lacewing Guithone bethouxi gen. et sp. nov., is described from the Middle Jurassic Jiulongshan Formation (Inner Mongolia, China). This taxon is characterized by robust body, head retracted under pronotum, and remarkable costal space (expanded basad, narrowed distad). Herein, we propose a detailed definition of the lineages of Ithonidae sensu lato (moth lacewings, giant lacewings, and montane lacewings) based on extant groups in order to clarify the systematics of fossil species within the taxon. The comparison shows that Guithone bethouxi gen. et sp. nov. unquestionably represents the earliest true moth lacewing, implying that lineage differentiations within Ithonidae sensu lato must have taken place before the Middle Jurassic. Furthermore the new genus possessing some particular venation characters, such as irrecurrent humeral veinlet and simplified crossveination in radial sector, represents an important intermediate group in the evolution of Ithonidae sensu lato.", "keyphrases": ["moth lacewing", "middle jurassic", "china"]}
{"id": "10.1111/2041-210X.12226", "title": "Body mass estimation in non\u2010avian bipeds using a theoretical conversion to quadruped stylopodial proportions", "abstract": "Body mass is strongly related to both physiological and ecological properties of living organisms. As a result, generating robust, broadly applicable models for estimating body mass in the fossil record provides the opportunity to reconstruct palaeobiology and investigate evolutionary ecology on a large temporal scale. A recent study provided strong evidence that the minimum circumference of stylopodial elements (humerus and femur) is conservatively associated with body mass in living quadrupeds. Unfortunately, this model is not directly applicable to extinct bipeds, such as non\u2010avian dinosaurs. This study presents a new equation that mathematically corrects the quadruped equation for use in bipeds. It is derived from the systemic difference in the circumference\u2010to\u2010area scaling relationship of two circles (hypothetical quadruped) and one circle (hypothetical biped), which represent the cross\u2010section of the main weight\u2010bearing limb bones. When applied to a newly constructed data set of femoral circumferences and body masses in living birds, the new equation reveals errors that are significantly lower than other published equations, but significantly higher than the error inherent in the avian data set. Such errors, however, are expected given the unique overall femoral circumference\u2013body mass scaling relationship found in birds. Body mass estimates for a sample of bipedal dinosaurs using the new model are consistent with recent estimates based on volumetric life reconstructions, but, in contrast, this equation is simpler to use, with the concomitant potential to provide a wider set of body mass estimates for extinct bipeds. Although it is evident that no one estimation model is flawless, the combined use of the corrected quadrupedal equations and the previously published quadrupedal equation offer a consistent approach with which to estimate body masses in both quadrupeds and bipeds. These models have implications for conducting large\u2010scale macroevolutionary analyses of body size throughout the evolutionary history of terrestrial vertebrates, and, in particular, across major changes in body plan, such as the evolution of bipedality in archosaurs and quadrupedality in dinosaurs.", "keyphrases": ["biped", "femur", "body mass"]}
{"id": "paleo.004558", "title": "Fossilization of melanosomes via sulfurization", "abstract": "Fossil melanin granules (melanosomes) are an important resource for inferring the evolutionary history of colour and its functions in animals. The taphonomy of melanin and melanosomes, however, is incompletely understood. In particular, the chemical processes responsible for melanosome preservation have not been investigated. As a result, the origins of sulfur\u2010bearing compounds in fossil melanosomes are difficult to resolve. This has implications for interpretations of original colour in fossils based on potential sulfur\u2010rich phaeomelanosomes. Here we use pyrolysis gas chromatography mass spectrometry (Py\u2010GCMS), fourier transform infrared spectroscopy (FTIR) and time of flight secondary ion mass spectrometry (ToF\u2010SIMS) to assess the mode of preservation of fossil microstructures, confirmed as melanosomes based on the presence of melanin, preserved in frogs from the Late Miocene Libros biota (NE Spain). Our results reveal a high abundance of organosulfur compounds and non\u2010sulfurized fatty acid methyl esters in both the fossil tissues and host sediment; chemical signatures in the fossil tissues are inconsistent with preservation of phaeomelanin. Our results reflect preservation via the diagenetic incorporation of sulfur, i.e. sulfurization (natural vulcanization), and other polymerization processes. Organosulfur compounds and/or elevated concentrations of sulfur have been reported from melanosomes preserved in various invertebrate and vertebrate fossils and depositional settings, suggesting that preservation through sulfurization is likely to be widespread. Future studies of sulfur\u2010rich fossil melanosomes require that the geochemistry of the host sediment is tested for evidence of sulfurization in order to constrain interpretations of potential phaeomelanosomes and thus of original integumentary colour in fossils.", "keyphrases": ["melanosomes", "sulfurization", "tissue", "fossilization", "chemistry"]}
{"id": "paleo.011467", "title": "A globally distributed durophagous marine reptile clade supports the rapid recovery of pelagic ecosystems after the Permo-Triassic mass extinction", "abstract": "Marine ecosystem recovery after the Permo-Triassic mass extinction (PTME) has been extensively studied in the shallow sea, but little is known about the nature of this process in pelagic ecosystems. Omphalosauridae, an enigmatic clade of open-water durophagous marine reptiles, potentially played an important role in the recovery, but their fragmentary fossils and uncertain phylogenetic position have hindered our understanding of their role in the process. Here we report the large basal ichthyosauriform Sclerocormus from the Early Triassic of China that clearly demonstrates an omphalosaurid affinity, allowing for the synonymy of the recently erected Nasorostra with Omphalosauridae. The skull also reveals the anatomy of the unique feeding apparatus of omphalosaurids, likely an adaptation for feeding on hard-shelled pelagic invertebrates, especially ammonoids. Morphofunctional analysis of jaws shows that omphalosaurids occupy the morphospace of marine turtles. Our discovery adds another piece of evidence for an explosive radiation of marine reptiles into the ocean in the Early Triassic and the rapid recovery of pelagic ecosystems after the PTME.", "keyphrases": ["rapid recovery", "pelagic ecosystem", "permo-triassic mass extinction", "early triassic"]}
{"id": "paleo.003664", "title": "Multivariate and Cladistic Analyses of Isolated Teeth Reveal Sympatry of Theropod Dinosaurs in the Late Jurassic of Northern Germany", "abstract": "Remains of theropod dinosaurs are very rare in Northern Germany because the area was repeatedly submerged by a shallow epicontinental sea during the Mesozoic. Here, 80 Late Jurassic theropod teeth are described of which the majority were collected over decades from marine carbonates in nowadays abandoned and backfilled quarries of the 19th century. Eighteen different morphotypes (A\u2014R) could be distinguished and 3D models based on micro-CT scans of the best examples of all morphotypes are included as supplements. The teeth were identified with the assistance of discriminant function analysis and cladistic analysis based on updated datamatrices. The results show that a large variety of theropod groups were present in the Late Jurassic of northern Germany. Identified specimens comprise basal Tyrannosauroidea, as well as Allosauroidea, Megalosauroidea cf. Marshosaurus, Megalosauridae cf. Torvosaurus and probably Ceratosauria. The formerly reported presence of Dromaeosauridae in the Late Jurassic of northern Germany could not be confirmed. Some teeth of this study resemble specimens described as pertaining to Carcharodontosauria (morphotype A) and Abelisauridae (morphotype K). This interpretation is however, not supported by discriminant function analysis and cladistic analysis. Two smaller morphotypes (N and Q) differ only in some probably size-related characteristics from larger morphotypes (B and C) and could well represent juveniles of adult specimens. The similarity of the northern German theropods with groups from contemporaneous localities suggests faunal exchange via land-connections in the Late Jurassic between Germany, Portugal and North America.", "keyphrases": ["late jurassic", "northern germany", "theropod tooth"]}
{"id": "10.1029/91PA02022", "title": "Opening the carbon isotope \"vital effect\" black box, 2, Quantitative model for interpreting foramini", "abstract": "Interpretation of carbon isotope records from late Quaternary planktonic foraminifers are confounded due to the presence of a significant physiological component in the carbon isotopic signal. A quantitative carbon isotope (QC) model is presented which relates the carbon isotopic composition of a foraminiferal shell to the physiological processes of respiration and symbiont photosynthesis and to the \u03b413C value of seawater \u03a3CO2. The QC model is calibrated with physiological and stable isotopic data from laboratory experiments with living planktonic foraminifers. Model simulations of chamber and shell \u03b413C values with the symbiont-bearing foraminifers, Orbulina universa and Globigerinoides sacculifer, suggest (1) variations in symbiont density and photosynthetic rate (light level or habitat depth) are the primary physiological parameters controlling intraspecific carbon isotopic variability in these species, (2) respiration has little effect on the \u03b413C of O. universa, and (3) each chamber in a multichambered foraminiferal test will have a distinct \u03b413C value depending on its position in the test whorl. Size:\u03b413C value relationships reported for G. sacculifer from fossil assemblages can be explained as a function of increasing symbiont density during ontogenetic development.", "keyphrases": ["carbon isotope", "vital effect", "foraminiferal shell"]}
{"id": "paleo.006372", "title": "The sauropodomorph biostratigraphy of the Elliot Formation of southern Africa: Tracking the evolution of Sauropodomorpha across the Triassic\u2013Jurassic boundary", "abstract": "The latest Triassic is notable for coinciding with the dramatic decline of many previously dominant groups, followed by the rapid radiation of Dinosauria in the Early Jurassic. Among the most common terrestrial vertebrates from this time, sauropodomorph dinosaurs provide an important insight into the changing dynamics of the biota across the Triassic\u2013Jurassic boundary. The Elliot Formation of South Africa and Lesotho preserves the richest assemblage of sauropodomorphs known from this age, and is a key index assemblage for biostratigraphic correlations with other similarly-aged global terrestrial deposits. Past assessments of Elliot Formation biostratigraphy were hampered by an overly simplistic biozonation scheme which divided it into a lower \u201c Euskelosaurus \u201d Range Zone and an upper Massospondylus Range Zone. Here we revise the zonation of the Elliot Formation by: (i) synthesizing the last three decades\u2019 worth of fossil discoveries, taxonomic revision, and lithostratigraphic investigation; and (ii) systematically reappraising the stratigraphic provenance of important fossil locations. We then use our revised stratigraphic information in conjunction with phylogenetic character data to assess morphological disparity between Late Triassic and Early Jurassic sauropodomorph taxa. Our results demonstrate that the Early Jurassic upper Elliot Formation is considerably more taxonomically and morphologically diverse than previously thought. In contrast, the sauropodomorph fauna of the Late Triassic lower Elliot Formation remains relatively poorly understood due to the pervasive incompleteness of many key specimens, as well as the relative homogeneity of their diagnostic character suites. Our metrics indicate that both Elliot Formation and global sauropodomorph assemblages had greater morphological disparity within the Early Jurassic than the Late Triassic. This result is discussed in the context of changing palaeoclimatic conditions, as well as macroevolutionary events associated with the end-Triassic extinction.", "keyphrases": ["elliot formation", "sauropodomorpha", "triassic\u2013jurassic boundary", "early jurassic"]}
{"id": "10.5194/cp-16-1667-2020", "title": "Surface-circulation change in the southwest Pacific Ocean across the Middle Eocene Climatic Optimum: inferences from dinoflagellate cysts and biomarker paleothermometry", "abstract": "Abstract. Global climate cooled from the early Eocene hothouse (\u223c52\u201350\u2009Ma) to the latest\nEocene (\u223c34\u2009Ma). At the same time, the tectonic evolution of the Southern Ocean was\ncharacterized by the opening and deepening of circum-Antarctic gateways, which affected both\nsurface- and deep-ocean circulation. The Tasmanian Gateway played a\u00a0key role in regulating ocean\nthroughflow between Australia and Antarctica. Southern Ocean surface currents through and around\nthe Tasmanian Gateway have left recognizable tracers in the spatiotemporal distribution of\nplankton fossils, including organic-walled dinoflagellate cysts. This spatiotemporal distribution\ndepends on both the physicochemical properties of the water masses and the path of surface-ocean\ncurrents. The extent to which climate and tectonics have influenced the distribution and\ncomposition of surface currents and thus fossil assemblages has, however, remained unclear. In\nparticular, the contribution of climate change to oceanographic changes, superimposed on long-term\nand gradual changes induced by tectonics, is still poorly understood. To disentangle the effects of tectonism and climate in the southwest Pacific Ocean, we target\na\u00a0climatic deviation from the long-term Eocene cooling trend: the Middle Eocene Climatic Optimum\n(MECO; \u223c40\u2009Ma). This 500\u2009kyr phase of global warming was unrelated\nto regional tectonism, and thus provides a\u00a0test case to investigate the ocean's physicochemical\nresponse to climate change alone. We reconstruct changes in surface-water circulation and\ntemperature in and around the Tasmanian Gateway during the MECO through new palynological and\norganic geochemical records from the central Tasmanian Gateway (Ocean Drilling Program Site 1170),\nthe Otway Basin (southeastern Australia), and the Hampden Beach section (New Zealand). Our results\nconfirm that dinocyst communities track specific surface-ocean currents, yet the variability\nwithin the communities can be driven by superimposed temperature change. Together with published\nresults from the east of the Tasmanian Gateway, our new results suggest a\u00a0shift in surface-ocean\ncirculation during the peak of MECO warmth. Simultaneous with high sea-surface temperatures in\nthe Tasmanian Gateway area, pollen assemblages indicate warm temperate rainforests with\nparatropical elements along the southeastern margin of Australia. Finally, based on new age\nconstraints, we suggest that a\u00a0regional southeast Australian transgression might have been\ncoincident with the MECO.\n", "keyphrases": ["southwest pacific ocean", "dinoflagellate cyst", "current"]}
{"id": "paleo.012869", "title": "Fossil Fishes from China Provide First Evidence of Dermal Pelvic Girdles in Osteichthyans", "abstract": "Background The pectoral and pelvic girdles support paired fins and limbs, and have transformed significantly in the diversification of gnathostomes or jawed vertebrates (including osteichthyans, chondrichthyans, acanthodians and placoderms). For instance, changes in the pectoral and pelvic girdles accompanied the transition of fins to limbs as some osteichthyans (a clade that contains the vast majority of vertebrates \u2013 bony fishes and tetrapods) ventured from aquatic to terrestrial environments. The fossil record shows that the pectoral girdles of early osteichthyans (e.g., Lophosteus, Andreolepis, Psarolepis and Guiyu) retained part of the primitive gnathostome pectoral girdle condition with spines and/or other dermal components. However, very little is known about the condition of the pelvic girdle in the earliest osteichthyans. Living osteichthyans, like chondrichthyans (cartilaginous fishes), have exclusively endoskeletal pelvic girdles, while dermal pelvic girdle components (plates and/or spines) have so far been found only in some extinct placoderms and acanthodians. Consequently, whether the pectoral and pelvic girdles are primitively similar in osteichthyans cannot be adequately evaluated, and phylogeny-based inferences regarding the primitive pelvic girdle condition in osteichthyans cannot be tested against available fossil evidence. Methodology/Principal Findings Here we report the first discovery of spine-bearing dermal pelvic girdles in early osteichthyans, based on a new articulated specimen of Guiyu oneiros from the Late Ludlow (Silurian) Kuanti Formation, Yunnan, as well as a re-examination of the previously described holotype. We also describe disarticulated pelvic girdles of Psarolepis romeri from the Lochkovian (Early Devonian) Xitun Formation, Yunnan, which resemble the previously reported pectoral girdles in having integrated dermal and endoskeletal components with polybasal fin articulation. Conclusions/Significance The new findings reveal hitherto unknown similarity in pectoral and pelvic girdles among early osteichthyans, and provide critical information for studying the evolution of pelvic girdles in osteichthyans and other gnathostomes.", "keyphrases": ["dermal pelvic girdle", "osteichthyan", "acanthodian", "placoderm", "holotype"]}
{"id": "paleo.005809", "title": "No (Cambrian) explosion and no (Ordovician) event: A single long-term radiation in the early Palaeozoic", "abstract": "The Cambrian 'Explosion', located by many authors between 540 and 520 million years ago (Ma), is considered to be an abrupt appearance in the fossil record of most animal phyla, with a sudden increase of complex morphologies across metazoan groups. In a few recent papers, the Great Ordovician Biodiversification 'Event' (GOBE) has similarly been restricted to a single dramatic biodiversification 'event' in the Darriwilian Stage of the Middle Ordovician Series, between 470 and 455 Ma, although historically the biodiversification is considered as an aggregation of radiation 'events' capturing a large and complex increase of taxonomic diversity of marine invertebrates covering the entire Ordovician. A review of biodiversity curves of marine organisms during the early Palaeozoic, including some based on data in the Paleobiology Database (PBDB) and the Geobiodiversity Database (GBDB), points towards a single, large-scale, long-term early Palaeozoic radiation of life that already started in the late Precambrian. An abrupt 'explosion' of diversity in the Cambrian or a significant 'event' in the Ordovician are not visible in our biodiversity studies, because they are either regional, or only reflect a single group of organisms. It is evident that the datasets remain incomplete, in particular those for many geographical areas and for several fossil groups, that are not covered by the PBDB and GBDB; also, such areas remain so far poorly or entirely unstudied. Some recently published biodiversity curves have to be considered with care, as the truly global diversity estimates of marine organisms during the early Palaeozoic remain elusive. Here, we argue that published curves of taxonomic richness, which show distinct periods of diversification, cannot sufficiently be disentangled from biases. We therefore question the existence of a distinct Cambrian 'Explosion' and global Ordovician 'Event' in the global datasets. Both terms, Cambrian 'Explosion' and Great Ordovician Biodiversification 'Event should be used as conceptional terms only. The first represents the appearance of almost all animal phyla during the late Precambrian and early Cambrian, whereas the second term embraces the numerous and complex radiations that occurred during the entire Ordovician.", "keyphrases": ["explosion", "early palaeozoic", "gobe"]}
{"id": "paleo.003013", "title": "New discoveries of glirids and eomyids (Mammalia, Rodentia) in the Early Miocene of the Junggar basin (Northern Xinjiang province, China)", "abstract": "We report herein new discoveries of Gliridae and Eomyidae (Mammalia, Rodentia) from the new Early Miocene locality XJ 200604, located northwest to the Burqin city, northern Xinjiang province, China. These specimens represent three taxa of Gliridae, including a new species (Miodyromys asiamediae nov. sp., Microdyromys aff. orientalis and Eliomys? sp.), and four taxa of Eomyidae (Asianeomys aff. engesseri, Asianeomys sp., Keramidomys sp. and Eomyidae indet). The identification of two forms that are closely related to Microdyromys orientalis and Asianeomys engesseri suggests an Early Miocene age of the locality but does not allow a more precise age determination. The new discoveries of Gliridae and Eomyidae again reveal the relative scarcity of the two families in the Early Miocene of Central Asia, in contrast to the coeval rich European record. Such a discrepancy in taxonomic diversity and abundance is hypothesized as resulting from different environmental evolutions during the Early Miocene, most notably the onset of a mid-latitude dry climate in Central Asia linked to combine effects of the Tibetan Plateau uplift and the retreat of the Paratethys Sea.", "keyphrases": ["mammalia", "rodentia", "early miocene"]}
{"id": "10.1073/pnas.1200644109", "title": "Late Middle Eocene primate from Myanmar and the initial anthropoid colonization of Africa", "abstract": "Reconstructing the origin and early evolutionary history of anthropoid primates (monkeys, apes, and humans) is a current focus of paleoprimatology. Although earlier hypotheses frequently supported an African origin for anthropoids, recent discoveries of older and phylogenetically more basal fossils in China and Myanmar indicate that the group originated in Asia. Given the Oligocene-Recent history of African anthropoids, the colonization of Africa by early anthropoids hailing from Asia was a decisive event in primate evolution. However, the fossil record has so far failed to constrain the nature and timing of this pivotal event. Here we describe a fossil primate from the late middle Eocene Pondaung Formation of Myanmar, Afrasia djijidae gen. et sp. nov., that is remarkably similar to, yet dentally more primitive than, the roughly contemporaneous North African anthropoid Afrotarsius. Phylogenetic analysis suggests that Afrasia and Afrotarsius are sister taxa within a basal anthropoid clade designated as the infraorder Eosimiiformes. Current knowledge of eosimiiform relationships and their distribution through space and time suggests that members of this clade dispersed from Asia to Africa sometime during the middle Eocene, shortly before their first appearance in the African fossil record. Crown anthropoids and their nearest fossil relatives do not appear to be specially related to Afrotarsius, suggesting one or more additional episodes of dispersal from Asia to Africa. Hystricognathous rodents, anthracotheres, and possibly other Asian mammal groups seem to have colonized Africa at roughly the same time or shortly after anthropoids gained their first toehold there.", "keyphrases": ["middle eocene", "myanmar", "colonization", "anthropoid primate", "african origin"]}
{"id": "10.1111/bij.12731", "title": "Eutherian morphological disparity across the end\u2010Cretaceous mass extinction", "abstract": "\u00a9 2015 The Linnean Society of London. In the aftermaths of mass extinction events, during radiations of clades, and in several other evolutionary scenarios, there is often a decoupling of taxonomic diversity and morphological disparity. The placental mammal radiation after the end-Cretaceous mass extinction is one of the archetypal adaptive radiations, but the change in morphological disparity of the entire skeleton has never been quantified across this important boundary. We reconstruct ancestral morphologies of 680 discrete morphological characters onto dated phylogenies of 177 mostly Cretaceous and Palaeogene eutherians (placental mammals and their stem relatives). Using a new approach to incorporate morphologies representing ghost lineages, we assess three measures of morphological disparity (sum of ranges, sum of variances and mean pairwise dissimilarity) across stage-level time bins within the Cretaceous and Palaeogene. We find that the range-based metric suggests that eutherian disparity increased immediately after the end-Cretaceous mass extinction, while both variance-based metrics declined from the Campanian to the Maastrichtian, but showed no change in disparity from the Maastrichtian to the Puercan - the first North American Land Mammal Age of the Paleocene. Increases in variance-based metrics lag behind the range-based metric and per-lineage accumulation rate, suggesting that the response of mammals to the Cretaceous-Palaeogene event was characterized by an early radiation that increased overall morphospace occupation, followed later by specialization that resulted in increased dissimilarity.", "keyphrases": ["morphological disparity", "mass extinction", "entire skeleton"]}
{"id": "10.1144/SP379.9", "title": "Non-dinosaurian Dinosauromorpha", "abstract": "Abstract Ichnological evidence suggests that dinosauromorphs originated by the Early Triassic, and skeletal remains of non-dinosaur representatives of the clade occur from the Anisian to the end of the Triassic. These taxa are small- to medium-sized, vary in feeding and locomotor features, and occurred over most of western Pangaea. They include the small lagerpetids from the Mid\u2013Late Triassic of Argentina and the United States, and the larger, quadrupedal Silesauridae, with records in the Middle Triassic of Africa and Argentina, and in the Late Triassic of Europe, the Americas and northern Africa. The former group represents the earliest diverging dinosauromorphs, whereas silesaurids are more closely related to Dinosauria. Other dinosauromorphs include the archetypal early dinosauriform Marasuchus lilloensis (Middle Triassic of Argentina) and poorly known/controversial taxa such as Lewisuchus admixtus and Saltopus elginensis. The earliest diverging dinosauromorphs may have preyed on small animals (including insects), but cranio-dental remains are rare; by contrast, most silesaurids probably included plant material in their diet, as indicated by their modified jaw apparatus and teeth. Our knowledge of the anatomy and thus relationships of non-dinosaurian Dinosauromorpha is still deficient, and we suspect that future discoveries will continue to reveal novel patterns and hypotheses of palaeobiology and biogeography.", "keyphrases": ["triassic", "silesauridae", "non-dinosaurian dinosauromorpha"]}
{"id": "paleo.009865", "title": "Revisiting the origin and diversification of vascular plants through a comprehensive Bayesian analysis of the fossil record", "abstract": "Summary Plants have a long evolutionary history, during which mass extinction events dramatically affected Earth's ecosystems and its biodiversity. The fossil record can shed light on the diversification dynamics of plant life and reveal how changes in the origination\u2013extinction balance have contributed to shaping the current flora. We use a novel Bayesian approach to estimate origination and extinction rates in plants throughout their history. We focus on the effect of the \u2018Big Five\u2019 mass extinctions and on estimating the timing of origin of vascular plants, seed plants and angiosperms. Our analyses show that plant diversification is characterized by several shifts in origination and extinction rates, often matching the most important geological boundaries. The estimated origin of major plant clades predates the oldest macrofossils when considering the uncertainties associated with the fossil record and the preservation process. Our findings show that the commonly recognized mass extinctions have affected each plant group differently and that phases of high extinction often coincided with major floral turnovers. For instance, after the Cretaceous\u2013Paleogene boundary we infer negligible shifts in diversification of nonflowering seed plants, but find significantly decreased extinction in spore\u2010bearing plants and increased origination rates in angiosperms, contributing to their current ecological and evolutionary dominance.", "keyphrases": ["diversification", "vascular plant", "mass extinction event"]}
{"id": "10.1029/PA001i003p00339", "title": "Late Quaternary paleoceanography of the tropical Atlantic, 2: The seasonal cycle of sea surface temperatures, 0\u201320,000 years B.P.", "abstract": "Foraminiferal species abundances are used to estimate seasonal variability of late Quaternary sea surface temperatures in the tropical Atlantic Ocean. Empirical orthogonal functions analysis of 28 time series isolates two patterns (modes) of variation. The dominant mode 1 reflects seasonal temperature contrast of the South Equatorial Current region 5\u00b0\u20136\u00b0C higher at the glacial maximum than at present, probably indicating larger seasonal variations of the southern trade winds. Forcing for this pattern may have come from equatorward compression of glacial climate zones due to high-latitude cooling in both hemispheres and/or suppression of meridional monsoonal circulation via feedback from northern hemisphere ice cover. When compared with CLIMAP estimates of lower seasonal variations of glacial age sea ice fronts in Antarctica, mode 1 suggests decoupling of low- and high- latitude seasonal cycles in the southern hemisphere on a glacial-interglacial scale. Mode 2 variations reflect seasonal contrast in sea surface temperature of 2\u00b0\u20133\u00b0C less 9000 to 14,000 years B.P. than at present along the equator and in the eastern subtropical Atlantic, perhaps related to an equatorial position of the Intertropical Convergence Zone, weakened trade winds, and/or strengthened monsoonal circulation during deglaciation. Our findings emphasize the need to isolate spatially coherent (and thus dynamically linked) patterns of climate change from a complex record of multiple climatic effects. Only then can effective tests of hypotheses be made with a coupled strategy of data acquisition and climate modeling.", "keyphrases": ["seasonal cycle", "sea surface temperature", "year b.p.", "cooling"]}
{"id": "paleo.010356", "title": "Evaluation of a New Method of Fossil Retrodeformation by Algorithmic Symmetrization: Crania of Papionins (Primates, Cercopithecidae) as a Test Case", "abstract": "Diagenetic distortion can be a major obstacle to collecting quantitative shape data on paleontological specimens, especially for three-dimensional geometric morphometric analysis. Here we utilize the recently -published algorithmic symmetrization method of fossil reconstruction and compare it to the more traditional reflection & averaging approach. In order to have an objective test of this method, five casts of a female cranium of Papio hamadryas kindae were manually deformed while the plaster hardened. These were subsequently \u201cretrodeformed\u201d using both algorithmic symmetrization and reflection & averaging and then compared to the original, undeformed specimen. We found that in all cases, algorithmic retrodeformation improved the shape of the deformed cranium and in four out of five cases, the algorithmically symmetrized crania were more similar in shape to the original crania than the reflected & averaged reconstructions. In three out of five cases, the difference between the algorithmically symmetrized crania and the original cranium could be contained within the magnitude of variation among individuals in a single subspecies of Papio. Instances of asymmetric distortion, such as breakage on one side, or bending in the axis of symmetry, were well handled, whereas symmetrical distortion remained uncorrected. This technique was further tested on a naturally deformed and fossilized cranium of Paradolichopithecus arvernensis. Results, based on a principal components analysis and Procrustes distances, showed that the algorithmically symmetrized Paradolichopithecus cranium was more similar to other, less-deformed crania from the same species than was the original. These results illustrate the efficacy of this method of retrodeformation by algorithmic symmetrization for the correction of asymmetrical distortion in fossils. Symmetrical distortion remains a problem for all currently developed methods of retrodeformation.", "keyphrases": ["retrodeformation", "algorithmic symmetrization", "crania"]}
{"id": "paleo.011741", "title": "Subfamily Limoniinae Speiser, 1909 (Diptera, Limoniidae) from Baltic Amber (Eocene): The Genus Elephantomyia Osten Sacken, 1860", "abstract": "A revision of the genus Elephantomyia Osten Sacken (Diptera: Limoniidae) from Baltic amber (Eocene) is presented. Four species--E. baltica Alexander, E. brevipalpa Loew, E. longirostris Loew, and E. pulchella Loew--are redescribed and documented with photographs and drawings. In addition, two new species of the genus are described: Elephantomyia bozenae sp. nov., and Elephantomyia irinae sp. nov. All these fossil species are placed within the subgenus Elephantomyia. A key to the extinct species of Elephantomyia is provided, and the genus' ecological pattern and evolutionary aspects are discussed.", "keyphrases": ["diptera", "limoniidae", "eocene", "elephantomyia"]}
{"id": "10.1371/journal.pone.0175594", "title": "Dietary resilience among hunter-gatherers of Tierra del Fuego: Isotopic evidence in a diachronic perspective", "abstract": "The native groups of Patagonia have relied on a hunter-gatherer economy well after the first Europeans and North Americans reached this part of the world. The large exploitation of marine mammals (i.e., seals) by such allochthonous groups has had a strong impact on the local ecology in a way that might have forced the natives to adjust their subsistence strategies. Similarly, the introduction of new foods might have changed local diet. These are the premises of our isotopic-based analysis. There is a large set of paleonutritional investigations through isotopic analysis on Fuegians groups, however a systematic exploration of food practices across time in relation to possible pre- and post-contact changes is still lacking. In this paper we investigate dietary variation in hunter-gatherer groups of Tierra del Fuego in a diachronic perspective, through measuring the isotopic ratio of carbon (\u220213C) and nitrogen (\u220215N) in the bone collagen of human and a selection of terrestrial and marine animal samples. The data obtained reveal an unexpected isotopic uniformity across prehistoric and recent groups, with little variation in both carbon and nitrogen mean values, which we interpret as the possible evidence of resilience among these groups and persistence of subsistence strategies, allowing inferences on the dramatic contraction (and extinction) of Fuegian populations.", "keyphrases": ["resilience", "tierra del fuego", "diachronic perspective"]}
{"id": "10.1017/s0022336000040439", "title": "The skull of Ekaltadeta ima (Marsupialia, Hypsiprymnodontidae?): An analysis of some marsupial cranial features and a re-investigation of propleopine phylogeny, with notes on the inference of carnivory in mammals", "abstract": "The near-complete skull of the Giant Rat-kangaroo Ekaltadeta ima is described from a middle Miocene deposit at Riversleigh, north western Queensland. Surprisingly, the results of phylogenetic analysis indicate no special relationship with the only other hypsiprymnodontids for which substantial cranial material is known (Hypsiprymnodon moschatus, H. bartholomaii), but within Macropodoidea, a number of derived features present in E. ima are found only in another extinct taxon, the Balbarinae. Recent studies have suggested that Balbarinae may not represent a basal macropodid clade as thought by most previous authors and furthermore that the subfamily is perhaps distinct from all other kangaroos. In light of these findings an interesting possibility is noted, i.e., that Propleopinae and Balbarinae may represent a monophyletic clade to the exclusion of all other taxa. Preliminary results of investigation into dietary habitus indicate that Propleopinae represents a radiation of medium- to large-sized omnivorous kangaroos. Within this clade it is reiterated that a tendency toward carnivory might be inferred from the relative importance of high amplitude vertical shearing versus horizontal shearing and/or crushing elements in the dentition.", "keyphrases": ["skull", "carnivory", "hypsiprymnodontid"]}
{"id": "10.1073/pnas.0808468106", "title": "Ecomorphological selectivity among marine teleost fishes during the end-Cretaceous extinction", "abstract": "Despite the attention focused on mass extinction events in the fossil record, patterns of extinction in the dominant group of marine vertebrates\u2014fishes\u2014remain largely unexplored. Here, I demonstrate ecomorphological selectivity among marine teleost fishes during the end-Cretaceous extinction, based on a genus-level dataset that accounts for lineages predicted on the basis of phylogeny but not yet sampled in the fossil record. Two ecologically relevant anatomical features are considered: body size and jaw-closing lever ratio. Extinction intensity is higher for taxa with large body sizes and jaws consistent with speed (rather than force) transmission; resampling tests indicate that victims represent a nonrandom subset of taxa present in the final stage of the Cretaceous. Logistic regressions of the raw data reveal that this nonrandom distribution stems primarily from the larger body sizes of victims relative to survivors. Jaw mechanics are also a significant factor for most dataset partitions but are always less important than body size. When data are corrected for phylogenetic nonindependence, jaw mechanics show a significant correlation with extinction risk, but body size does not. Many modern large-bodied, predatory taxa currently suffering from overexploitation, such billfishes and tunas, first occur in the Paleocene, when they appear to have filled the functional space vacated by some extinction victims.", "keyphrases": ["marine teleost fish", "end-cretaceous extinction", "body size", "extinction risk", "ecomorphological selectivity"]}
{"id": "10.7717/peerj.3706", "title": "Dinosaur origin of egg color: oviraptors laid blue-green eggs", "abstract": "Protoporphyrin (PP) and biliverdin (BV) give rise to the enormous diversity in avian egg coloration. Egg color serves several ecological purposes, including post-mating signaling and camouflage. Egg camouflage represents a major character of open-nesting birds which accomplish protection of their unhatched offspring against visually oriented predators by cryptic egg coloration. Cryptic coloration evolved to match the predominant shades of color found in the nesting environment. Such a selection pressure for the evolution of colored or cryptic eggs should be present in all open nesting birds and relatives. Many birds are open-nesting, but protect their eggs by continuous brooding, and thus exhibit no or minimal eggshell pigmentation. Their closest extant relatives, crocodiles, protect their eggs by burial and have unpigmented eggs. This phylogenetic pattern led to the assumption that colored eggs evolved within crown birds. The mosaic evolution of supposedly avian traits in non-avian theropod dinosaurs, however, such as the supposed evolution of partially open nesting behavior in oviraptorids, argues against this long-established theory. Using a double-checking liquid chromatography ESI-Q-TOF mass spectrometry routine, we traced the origin of colored eggs to their non-avian dinosaur ancestors by providing the first record of the avian eggshell pigments protoporphyrin and biliverdin in the eggshells of Late Cretaceous oviraptorid dinosaurs. The eggshell parataxon Macroolithus yaotunensis can be assigned to the oviraptor Heyuannia huangi based on exceptionally preserved, late developmental stage embryo remains. The analyzed eggshells are from three Late Cretaceous fluvial deposits ranging from eastern to southernmost China. Reevaluation of these taphonomic settings, and a consideration of patterns in the porosity of completely preserved eggs support an at least partially open nesting behavior for oviraptorosaurs. Such a nest arrangement corresponds with our reconstruction of blue-green eggs for oviraptors. According to the sexual signaling hypothesis, the reconstructed blue-green eggs support the origin of previously hypothesized avian paternal care in oviraptorid dinosaurs. Preserved dinosaur egg color not only pushes the current limits of the vertebrate molecular and associated soft tissue fossil record, but also provides a perspective on the potential application of this unexplored paleontological resource.", "keyphrases": ["egg color", "oviraptor", "biliverdin"]}
{"id": "paleo.004398", "title": "CALIBRATED DIVERSITY, TREE TOPOLOGY AND THE MOTHER OF MASS EXTINCTIONS: THE LESSON OF TEMNOSPONDYLS", "abstract": "Abstract:\u2002 Three family\u2010level cladistic analyses of temnospondyl amphibians are used to evaluate the impact of taxonomic rank, tree topology, and sample size on diversity profiles, origination and extinction rates, and faunal turnover. Temnospondyls are used as a case study for investigating replacement of families across the Permo\u2010Triassic boundary and modality of recovery in the aftermath of the end\u2010Permian mass extinction. Both observed and inferred (i.e. tree topology\u2010dependent) values of family diversity have a negligible effect on the shape of the diversity curve. However, inferred values produce both a flattening of the curve throughout the Cisuralian and a less pronounced increase in family diversity from Tatarian through to Induan than do observed values. Diversity curves based upon counts of genera and species display a clearer distinction between peaks and troughs. We use rarefaction techniques (specifically, rarefaction of the number of genera and species within families) to evaluate the effect of sampling size on the curve of estimated family\u2010level diversity during five time bins (Carboniferous; Cisuralian; Guadalupian\u2013Lopingian; Early Triassic; Middle Triassic\u2013Cretaceous). After applying rarefaction, we note that Cisuralian and Early Triassic diversity values are closer to one another than they are when the observed number of families is used; both values are also slightly higher than the Carboniferous estimated diversity. The Guadalupian\u2013Lopingian value is lower than raw data indicate, reflecting in part the depauperate land vertebrate diversity from the late Cisuralian to the middle Guadalupian (Olson\u2019s gap). The time\u2010calibrated origination and extinction rate trajectories plot out close to one another and show a peak in the Induan, regardless of the tree used to construct them. Origination and extinction trajectories are disjunct in at least some Palaeozoic intervals, and background extinctions exert a significant role in shaping temnospondyl diversity in the lowermost Triassic. Finally, species\u2010, genus\u2010, and family trajectories consistently reveal a rapid increase in temnospondyl diversity from latest Permian to earliest Triassic as well as a decline near the end of the Cisuralian. However, during the rest of the Cisuralian family diversity increases slightly and there is no evidence for a steady decline, contrary to previous reports.", "keyphrases": ["tree", "mass extinction", "amphibian", "triassic", "olson"]}
{"id": "10.1666/09050.1", "title": "The use of MSR (Minimum Sample Richness) for sample assemblage comparisons", "abstract": "Abstract Minimum Sample Richness (MSR) is defined as the smallest number of taxa that must be recorded in a sample to achieve a given level of inter-assemblage classification accuracy. MSR is calculated from known or estimated richness and taxonomic similarity. Here we test MSR for strengths and weaknesses by using 167 published mammalian local faunas from the Paleogene and early Neogene of the Quercy and Limagne area (Massif Central, southwestern France), and then apply MSR to 84 Oligo-Miocene faunas from Riversleigh, northwestern Queensland, Australia. In many cases, MSR is able to detect the assemblages in the data set that are potentially too incomplete to be used in a similarity-based comparative taxonomic analysis. The results show that the use of MSR significantly improves the quality of the clustering of fossil assemblages. We conclude that this method can screen sample assemblages that are not representative of their underlying original living communities. Ultimately, it can be used to identify which assemblages require further sampling before being included in a comparative analysis.", "keyphrases": ["msr", "minimum sample richness", "local faunas", "riversleigh"]}
{"id": "10.1029/2007PA001545", "title": "Bottom water anoxia, inoceramid colonization, and benthopelagic coupling during black shale deposition on Demerara Rise (Late Cretaceous western tropical North Atlantic)", "abstract": "[1]\u00a0The bulk rock geochemistry and inoceramid isotopic composition from Cenomanian to Santonian, finely laminated, organic-rich black shales, recovered during Ocean Drilling Program Leg 207 on Demerara Rise (western tropical North Atlantic), suggest persistent anoxic (free H2S) conditions within the sediments and short-term variations within a narrow range of anoxic to episodically dysoxic bottom waters over a \u223c15 Ma time interval. In addition to being organic-rich, the 50\u201390 m thick sections examined exhibit substantial bulk rock enrichments of Si, P, Ba, Cu, Mo, Ni, and Zn relative to World Average Shale. These observations point to high organic burial fluxes, likely driven by high primary production rates, which led to the establishment of intensely sulfidic pore waters and possibly bottom waters, as well as to the enrichments of Cr, Mo, U, and V in the sediments. At the same time, the irregular presence of benthic inoceramids and foraminifera in this facies demonstrates that the benthic environment could not have been continuously anoxic. The \u03b413C and \u03b415N values of the inoceramid shell organics provide no evidence of chemosymbiosis and are consistent with pelagic rain as being a significant food source. Demerara Rise inoceramids also exhibit well-defined, regularly spaced growth lines that are tracked by \u03b413C and \u03b418O variations in shell carbonate that cannot be simply explained by diagenesis. Instead, productivity variations in surface waters may have paced the growth of the shells during brief oxygenation events suitable for benthic inoceramid settlement. These inferences imply tight benthopelagic coupling and more dynamic benthic conditions than generally portrayed during black shale deposition. By invoking different temporal scales for geochemical and paleontological data, this study resolves recent contradictory conclusions (e.g., sulfidic sedimentary conditions versus dysoxic to suboxic benthic waters) drawn from studies of either sediment geochemistry or fossil distributions alone on Demerara Rise. This variability may be relevant for discussions of black shales in general.", "keyphrases": ["benthopelagic coupling", "black shale deposition", "tropical north atlantic"]}
{"id": "paleo.004718", "title": "The variations in the East Asian summer monsoon over the past 3 kyrs and the controlling factors", "abstract": "the mechanisms driving the variations in the centennial-scale east Asian summer monsoon (eAsM) remain unclear. Here, we use the \u03b4 18 o records from adult ostracode shells to reconstruct the eAsM variations over the last 3 kyrs in southwestern Japan. A common variation with a 200 yr periodicity among the Asian monsoonal regions was recognized between BC 800 and BC 100. Since then, neither a correlation between the eAsM variation and solar activity or a common eAsM variation through eAsM regions has been identified. The evidence reveals that solar activity dominantly affected the centennialscale EASM variations throughout Asian monsoonal regions until BC 100. Furthermore, factors other than solar activity that varied and differed in specific regions controlled the EASM intensity due to decreasing summer solar insolation in the Northern Hemisphere after BC 100. These relations indicate that the dominant factor that affects the EASM variations shifts according to the solar insolation intensity.\nClimates in Asia are strongly controlled by monsoons that are linked to the global climate 1,2 . The East Asian monsoon, which is one of the largest monsoon systems, covers the regions including China, the Korean Peninsula and Japan 3 . The East Asian monsoon is composed of southeastern winds in summer and northwestern winds in winter. The summer monsoon transports a large volume of water vapour to the continents, providing important water resources. High-resolution speleothem records from caves have clarified the variations in the East Asian summer monsoon (EASM) and their relations to other climate and sun patterns. In particular, new records from various regions over the last two decades have improved the understanding of monsoon mechanisms and the driving forces during the Quaternary 4,5 . Numerous EASM records, particularly those from stalagmites in Chinese caves, have indicated that both the orbital-scale and millennial-scale EASM variations are mainly due to solar insolation [4] [5] [6] [7] [8] [9] . In addition to sun activity, CO 2 concentrations 10 , the El Ni\u00f1o-Southern Oscillation (ENSO) 11 , and climate in the high latitudes of the Northern Hemisphere 4,12 have been proposed to be strongly linked to the intensity of the Asian summer monsoon. However, due to the small number of centennial-scale EASM records compared to the number of orbital-and millennial-scale records, coherent centennial-scale EASM variations and the relationships between the centennial-scale EASM variations and solar activity remain vague.\nRegardless of the significance and usefulness of the \u03b4 18 O records in stalagmites, their inconsistencies between nearby caves have been recognized 7, 13 . Furthermore, there are controversies that the \u03b4 18 O records in stalagmites from southern China reflect the isotopic compositions of water vapour from the upstream source region and not the EASM intensity in southern China 12,14-17 . Thus, the EASM records derived from other materials are required.\nOstracoda is a microcrustacea that inhabits aquatic environments throughout the world. The calcareous shells of Ostracoda are well preserved in the bottom sediments of freshwater lakes, brackish lakes and marine environments 18 . The \u03b4 18 O of the adult shell of a brackish species Bicornucythere bisanensis has been used as a tool to reconstruct the past summer precipitation induced by the EASM in Lake Nakaumi, southwest Japan 19 (Fig. 1 ). According to the EASM records based on this method, centennial-scale EASM variations with periodicities of 300-500 yrs and no relationship with solar activity during the last 1.8 kyrs were defined. This result disagreed with the previous observations that the EASM was strongly linked to solar activities, as found in orbital-and millennial-scale EASM variations. In the present study, we reconstructed the centennial-scale EASM intensity over the last 3 kyrs to reveal the common EASM intensity and its relation to solar activity.", "keyphrases": ["east", "summer monsoon", "japan"]}
{"id": "paleo.003364", "title": "Primates in the Eocene", "abstract": "The mammalian order Primates made its first appearance in the fossil record during the Paleocene-Eocene thermal maximum (PETM), the global greenhouse warming event that marks the beginning of the Eocene. Two primate superfamilies, Tarsioidea and Adapoidea, dominate early and middle Eocene primate faunas. Warm climates enabled primates to thrive, and warming events within the Eocene facilitated cosmopolitan dispersal. Declining diversity at the end of the Eocene reflects environmental cooling. Fossils of earliest Tarsioidea and Adapoidea are similar dentally, often confused, and appear closely related as stem or crown Haplorhini. The superfamily Tarsioidea is represented by a single genus, Tarsius, living today, while Adapoidea appear to be ancestral to living Anthropoidea. Little is known of the Eocene history of strepsirrhine Lemuroidea and Lorisoidea. Temporal scaling of molecular clock ages suggests that Strepsirrhini appeared before Haplorhini in the Paleocene or possibly with Haplorhini at the beginning of the Eocene. Substantial skeletons of Eocene primates like those of adapoid Darwinius and Europolemur from Messel in Germany and Notharctus and Smilodectes from western North America constrain phylogenetic interpretation of primate relationships much more than dental remains ever can. A specialised grasping foot distinguishes early primates from other mammals. Traits associated in a functional complex include replacement of claws by nails on all digits; movement of the pedal fulcrum from the metatarsals to the tarsals; elongation of digit IV relative to digit III, with reduction of digit II and sometimes III; and then secondary development of a grooming claw or claws on digits II and sometimes III. The specialised grasping foot of early primates was later moderated in the emergence of anthropoid primates.", "keyphrases": ["eocene", "adapoidea", "notharctus", "primate"]}
{"id": "10.1080/14772019.2016.1267666", "title": "A new otter of giant size, Siamogale melilutra sp. nov. (Lutrinae: Mustelidae: Carnivora), from the latest Miocene Shuitangba site in north-eastern Yunnan, south-western China, and a total-evidence phylogeny of lutrines", "abstract": "Otters (subfamily Lutrinae) are semi-aquatic predators in the family Mustelidae. Modern otters have a worldwide distribution but their fossil record is poor, often consisting of fragmentary jaws and teeth. Multiple lineages have developed bunodont dentitions with enlargements of molars, usually for cracking molluscs or other hard foods. Some lineages have evolved badger-like teeth and, as a result, were often confused with melines (Old World badger clade). Siamogale thailandica Ginsburg, Invagat, & Tassy, 1983 from the middle Miocene basin of Mae Moh in northern Thailand is one such species, whose fragmentary dental remains have thus far impeded our understanding. A new species of fossil otter, Siamogale melilutra sp. nov., represented by a nearly complete cranium, mandible and partial skeletons of at least three individuals, was recovered from the latest Miocene (\u223c6.2 Ma) lignite beds of the Shuitangba Site in north-eastern Yunnan Province, south-western China. Computed tomography (CT) restoration of the crushed skull reveals a combination of otter-like and badger-like cranial and dental characteristics. The new species belongs to the Lutrinae because of its possession of a large infraorbital canal and ventral expansion of the mastoid process, among other traits. A distally expanded M1, however, gives a badger-like appearance. In overall morphology the Shuitangba otter is closest to Siamogale thailandica. A previously described jaw (\u2018Lutra\u2019 aonychoides) from the early Pliocene of the Yushe Basin in north China is also here referred to S. melilutra. No previous attempt has been made to provide a global phylogenetic framework for otters. We present the first combined morphological and molecular (nuclear and mitochondrial DNAs) character matrices of five extant (Pteronura, Lontra, Enhydra, Aonyx, Lutra) and eight extinct genera (Tyrrhenolutra, Paralutra, Paludolutra, Enhydritherium, Siamogale, Vishnuonyx, Sivaonyx, Enhydriodon) to better understand the evolution of bunodont otters. Parsimony and Bayesian analyses consistently recover an eastern Asian clade that includes forms from Shuitangba, Yushe and Mae Moh, all of which are referred to Siamogale. http://zoobank.org/urn:lsid:zoobank.org:pub:5C637018-0772-4C78-AA4B-783B71085D9D", "keyphrases": ["otter", "lutrinae", "south-western china"]}
{"id": "paleo.000837", "title": "Automatic taxonomic identification based on the Fossil Image Dataset (>415,000 images) and deep convolutional neural networks", "abstract": "Abstract. The rapid and accurate taxonomic identification of fossils is of great significance in paleontology, biostratigraphy, and other fields. However, taxonomic identification is often labor-intensive and tedious, and the requisition of extensive prior knowledge about a taxonomic group also requires long-term training. Moreover, identification results are often inconsistent across researchers and communities. Accordingly, in this study, we used deep learning to support taxonomic identification. We used web crawlers to collect the Fossil Image Dataset (FID) via the Internet, obtaining 415,339 images belonging to 50 fossil clades. Then we trained three powerful convolutional neural networks on a high-performance workstation. The Inception-ResNet-v2 architecture achieved an average accuracy of 0.90 in the test dataset when transfer learning was applied. The clades of microfossils and vertebrate fossils exhibited the highest identification accuracies of 0.95 and 0.90, respectively. In contrast, clades of sponges, bryozoans, and trace fossils with various morphologies or with few samples in the dataset exhibited a performance below 0.80. Visual explanation methods further highlighted the discrepancies among different fossil clades and suggested similarities between the identifications made by machine classifiers and taxonomists. Collecting large paleontological datasets from various sources, such as the literature, digitization of dark data, citizen-science data, and public data from the Internet may further enhance deep learning methods and their adoption. Such developments will also possibly lead to image-based systematic taxonomy to be replaced by machine-aided classification in the future. Pioneering studies can include microfossils and some invertebrate fossils. To contribute to this development, we deployed our model on a server for public access at www.ai-fossil.com.", "keyphrases": ["taxonomic identification", "fossil image dataset", "convolutional neural network", "training", "web crawler"]}
{"id": "10.1002/gea.20234", "title": "A micromorphological analysis of stratigraphic integrity and site formation at Cactus Hill, an Early Paleoindian and hypothesized pre\u2010Clovis occupation in south\u2010central Virginia, USA", "abstract": "Twenty thin sections were studied from Cactus Hill, a ca. 20 ka stratified sand dune site in Virginia, USA, with a Clovis and hypothesized pre\u2010Clovis component. The high\u2010resolution soil micromorphology investigation focused on testing the integrity of Clovis and pre\u2010Clovis stratigraphy from one location where there is a high density of artifacts. Site formation processes were dominated by eolian (dune) sand formation. There was also ephemeral topsoil development and associated occupation, along with their penecontemporaneous disturbance and dispersal by scavenging animals (assumed) and localized down\u2010working by small invertebrate mesofauna (as evidenced by aggregates of fine phytolith\u2010rich humic soil and fine soil\u2010coated charcoal fragments). Partial erosion of these occupation soils (deflation?) was followed by successive sand burial. Post\u2010depositional processes affecting these sand\u2010buried occupations involved only small\u2010scale bioturbation and overprinting of clay lamellae, suggesting site stratigraphy has been stable for a long time. Soil micromorphological analysis has defined a difference between occupational units (pre\u2010Clovis and Clovis) and sterile units found between these units as well as above and below. In summary, according to this analysis, the site appears intact with only minor disturbances affecting the long\u2010term integrity of the stratigraphy. \u00a9 2008 Wiley Periodicals, Inc.", "keyphrases": ["micromorphological analysis", "integrity", "cactus hill"]}
{"id": "paleo.004889", "title": "A well-preserved respiratory system in a Silurian ostracod", "abstract": "Ostracod crustaceans are diverse and ubiquitous in aqueous environments today but relatively few known species have gills. Ostracods are the most abundant fossil arthropods but examples of soft-part preservation, especially of gills, are exceptionally rare. A new ostracod, Spiricopia aurita (Myodocopa), from the marine Silurian Herefordshire Lagerst\u00e4tte (430 Mya), UK, preserves appendages, lateral eyes and gills. The respiratory system includes five pairs of gill lamellae with hypobranchial and epibranchial canals that conveyed haemolymph. A heart and associated vessels had likely evolved in ostracods by the Mid-Silurian.", "keyphrases": ["respiratory system", "ostracod", "silurian herefordshire lagerst\u00e4tte"]}
{"id": "10.1098/rstb.1978.0066", "title": "Aspects of the adaptive morphology and evolution of the Trigoniidae", "abstract": "During the Jurassic and Early Cretaceous, the Trigoniidae were the dominant family of shallow-burrowing bivalves of warm, shallow seas. Neotrigonia is the only genus that survives today. Judging from the biology of Neotrigonia and the functional morphology and occurrence of extinct genera, the Trigoniidae represent an advanced family of burrowing Bivalvia. The family has been characterized by efficient locomotion, owing in large part to the presence of an unusually muscular foot, resembling that of the living Cardiidae. Other unusual features of the Trigoniidae relate to the presence of the foot. Complex hinge teeth with secondary dentition evolved to maintain valve alignment at the wide angles of gape required for extrusion of the foot. Myophorous buttresses evolved to support the large anterior hinge teeth. These anterior features seem to have obstructed the evolution of a prosogyrous shape of the kind that facilitates burrowing within many other bivalve taxa. Alternatively, there evolved in the Trigoniidae various kinds of external shell ornamentation that aided in burrowing. Thus, the many unusual morphological features of the Trigoniidae have been strongly coadaptive. The Mesozoic Trigoniidae seem to have been more advanced animals than any shallow-burrowing, suspension-feeding bivalves of the Palaeozoic and also than certain successful living groups with similar modes of life. Though slightly less advanced than the Cardiidae, they can be regarded as the cockles of the Mesozoic. Had the group not suddenly been decimated by environmental deterioration at the end of the Mesozoic, it would undoubtedly flourish today. Neotrigonia has, in fact, speciated at a high rate in comparison with other living genera of bivalves. A relatively recent origin and lack of primitive features disqualify Neotrigonia from status as a living fossil genus. It is the sole survivor of its family, but an advanced and modern animal nonetheless.", "keyphrases": ["morphology", "trigoniidae", "foot"]}
{"id": "10.1080/14772019.2017.1336579", "title": "Skull and postcranium of the bystrowianid Bystrowiella schumanni from the Middle Triassic of Germany, and the position of chroniosuchians within Tetrapoda", "abstract": "Chroniosuchians form a mainly terrestrial or semi-terrestrial clade of Permian and Triassic crocodile- or varanid-like tetrapods, usually considered stem amniotes, but with disputed affinities within that grade. Two groups can be distinguished, the chroniosuchids and bystrowianids. Whereas the chroniosuchid skull and postcranium are well known, our knowledge of bystrowianids is restricted mainly to isolated vertebrae and osteoderms. The Middle Triassic bystrowianid Bystrowiella schumanni from south-western Germany was identified as the first taxon of this clade outside Russia and China, based on the morphology of its vertebrae and osteoderms. Here we expand on a full description of cranial and postcranial remains from this taxon, based on a partially articulated specimen and further isolated material. The material comprises large parts of the dermal skull roof, the pectoral girdle, ribs and limbs, and sheds light on many anatomical regions formerly unknown in bystrowianids. Among the autapomorphic features of Bystrowiella are the premaxilla with an edentulous crest lateral to the choana, the premaxillary teeth with conspicuous size differences, the jugal with an extremely long, narrow anterior process, and the enlarged postparietals and tabulars forming facets for articulation with the anteriormost osteoderm. As in chroniosuchids, the pre- and postfrontal are not in contact, but unlike in chroniosuchids, the internarial fontanelle and the antorbital fenestra are absent. In the amniote-like postcranium, the interclavicle is slender and has a conspicuous parasternal process, the humerus is waisted and bears a short supinator process, and the long, curved trunk ribs have widely separated rib heads and a slender shaft without blades or processes. Phylogenetic analysis, particularly based on numerous new postcranial features, supports the monophyly of chroniosuchians, even when the constituent synapomorphies (osteoderm and vertebral characters) are excluded from the matrix. Chroniosuchians nest at the base of the amniote stem, forming an unresolved polytomy with Silvanerpeton, embolomeres and more advanced stem amniotes.", "keyphrases": ["postcranium", "germany", "chroniosuchian"]}
{"id": "10.1086/383062", "title": "Adaptation, Niche Conservatism, and Convergence: Comparative Studies of Leaf Evolution in the California Chaparral", "abstract": "Small leaves and low specific leaf area (SLA) have long been viewed as adaptations to Mediterranean\u2010type climates in many species of evergreen woody plants. However, paleobotanical and floristic evidence suggests that in many cases these traits originated prior to the advent of the summer\u2010drought climate regime. In this study, molecular phylogenies and ancestral state reconstructions were used to test the hypothesis of adaptive leaf evolution in 12 lineages of evergreen shrubs in the California chaparral. Across all lineages there was a small but significant shift toward lower SLA, but there were no trends in leaf size evolution. For individual lineages, adaptive changes were detected in only three cases for SLA and in one case for leaf size. Three of these cases of evolutionary change were observed in taxa derived from cool temperate ancestors (e.g., Heteromeles). In contrast, most lineages originating from subtropical ancestors exhibited relative stasis in leaf trait evolution (e.g., Ceanothus). The absence of change suggests that ancestors of chaparral taxa had already acquired appropriate traits that contributed to their success under Mediterranean\u2010type climates. These results illustrate how biogeographic history may influence patterns of trait evolution and adaptation and highlight the contribution of ecological sorting processes to the assembly and functional ecology of regional biotas.", "keyphrases": ["leaf evolution", "california chaparral", "ancestral state reconstruction"]}
{"id": "10.1017/S0094837300011702", "title": "Locomotor diversity within past and present guilds of large predatory mammals", "abstract": "The impact of environment, interspecific competition, and, to a lesser extent history, on the structure of the guild of large predatory mammals is explored in one fossil and four Recent communities. Two aspects are emphasized: (1) the number of species within each guild and (2) the extent of locomotor convergence as inferred from morphology among the constituent species. Locomotor behavior reflects habitat choice, hunting mode, and escape strategy, all of which appear to be important avenues of adaptive divergence among coexisting predators. Locomotor behavior in extinct and extant predators is determined from body weight and five measured characteristics of the postcranial skeleton, including ungual shape, elbow shape, and limb proportions. Results indicate that levels of morphologic and inferred ecologic similarity between large predators are higher in the tropical grassland guild of East Africa than in the equivalent guilds of either tropical or temperate forest. This may be due to the great density and diversity of terrestrial herbivores in the productive grasslands. The fossil guild, from the Late Chadron\u2013Orellan (Oligocene) of North America, appears most similar to the tropical forest guilds, but the predators seem to have been slower and more robust than their modern counterparts. Since the Orellan represents an early stage in the evolution of large, fissiped carnivores, both ancestry and time could have influenced Orellan guild structure.", "keyphrases": ["guild", "large predatory mammal", "postcranial skeleton"]}
{"id": "paleo.003566", "title": "An unusual new genus of istiodactylid pterosaurfrom China based on a near complete specimen", "abstract": "A new genus and species of istiodactylid pterosaur, Luchibang xingzhe gen. et sp. nov., from the Lower Cretaceous Yixian Formation of China is erected based on a near complete specimen lacking only the posterior of the skull and the tail. The holotype individual is skeletally immature and already bigger than most istiodactylids suggesting a large wingspan at adult. This is the most complete istiodactylid specimen known to date and provides new information on the anatomy of this group and their putative ecology. The animal is unusual in having postcranial robust and elongate hindlimbs, which marks it as different to other istiodactylids and other pteranodontoids.", "keyphrases": ["new genus", "istiodactylid", "near complete speciman"]}
{"id": "paleo.003430", "title": "Tetrapod distribution and temperature rise during the Permian\u2013Triassic mass extinction", "abstract": "The Permian\u2013Triassic mass extinction (PTME) had an enormous impact on life in three ways: by substantially reducing diversity, by reshuffling the composition of ecosystems and by expelling life from the tropics following episodes of intense global warming. But was there really an \u2018equatorial tetrapod gap', and how long did it last? Here, we consider both skeletal and footprint data, and find a more complex pattern: (i) tetrapods were distributed both at high and low latitudes during this time; (ii) there was a clear geographic disjunction through the PTME, with tetrapod distribution shifting 10\u201315\u00b0 poleward; and (iii) there was a rapid expansion phase across the whole of Pangea following the PTME. These changes are consistent with a model of generalized migration of tetrapods to higher latitudinal, cooler regions, to escape from the superhot equatorial climate in the earliest Triassic, but the effect was shorter in time scale, and not as pronounced as had been proposed. In the recovery phase following the PTME, this episode of forced range expansion also appears to have promoted the emergence and radiation of entirely new groups, such as the archosaurs, including the dinosaurs.", "keyphrases": ["low latitude", "migration", "tetrapod distribution", "early triassic"]}
{"id": "10.7717/peerj.6088", "title": "The Early Pliocene extinction of the mega-toothed shark Otodus megalodon: a view from the eastern North Pacific", "abstract": "The extinct giant shark Otodus megalodon is the last member of the predatory megatoothed lineage and is reported from Neogene sediments from nearly all continents. The timing of the extinction of Otodus megalodon is thought to be Pliocene, although reports of Pleistocene teeth fuel speculation that Otodus megalodon may still be extant. The longevity of the Otodus lineage (Paleocene to Pliocene) and its conspicuous absence in the modern fauna begs the question: when and why did this giant shark become extinct? Addressing this question requires a densely sampled marine vertebrate fossil record in concert with a robust geochronologic framework. Many historically important basins with stacked Otodus-bearing Neogene marine vertebrate fossil assemblages lack well-sampled and well-dated lower and upper Pliocene strata (e.g., Atlantic Coastal Plain). The fossil record of California, USA, and Baja California, Mexico, provides such an ideal sequence of assemblages preserved within well-dated lithostratigraphic sequences. This study reviews all records of Otodus megalodon from post-Messinian marine strata from western North America and evaluates their reliability. All post-Zanclean Otodus megalodon occurrences from the eastern North Pacific exhibit clear evidence of reworking or lack reliable provenance; the youngest reliable records of Otodus megalodon are early Pliocene, suggesting an extinction at the early-late Pliocene boundary (\u223c3.6 Ma), corresponding with youngest occurrences of Otodus megalodon in Japan, the North Atlantic, and Mediterranean. This study also reevaluates a published dataset, thoroughly vetting each occurrence and justifying the geochronologic age of each, as well as excluding several dubious records. Reanalysis of the dataset using optimal linear estimation resulted in a median extinction date of 3.51 Ma, somewhat older than a previously proposed Pliocene-Pleistocene extinction date (2.6 Ma). Post-middle Miocene oceanographic changes and cooling sea surface temperature may have resulted in range fragmentation, while alongside competition with the newly evolved great white shark (Carcharodon carcharias) during the Pliocene may have led to the demise of the megatoothed shark. Alternatively, these findings may also suggest a globally asynchronous extinction of Otodus megalodon.", "keyphrases": ["pliocene", "shark otodus megalodon", "eastern north pacific"]}
{"id": "paleo.004476", "title": "SPECIES DISCRIMINATION AND EVOLUTIONARY MODE OF BUCHIA (BIVALVIA: BUCHIIDAE) FROM UPPER JURASSIC\u2013LOWER CRETACEOUS STRATA OF GRASSY ISLAND, BRITISH COLUMBIA, CANADA", "abstract": "Abstract:\u2002 Buchiid bivalves are geographically widespread in Upper Jurassic and Lower Cretaceous strata of the Northern Hemisphere. They are often abundant and their short stratigraphic ranges make them ideal biostratigraphic index fossils; these characteristics also render them useful for study of evolutionary patterns. We used multivariate methods to determine if we could discriminate between species of Buchia and examine how morphological characters change through time within the genus. Using ten morphological characters to describe shell shape and size, we tested for taxonomic differences and morphologic change in populations of buchiids collected from a single stratigraphic section on Grassy Island, located along the west coast of Vancouver Island, British Columbia. Morphometric analysis utilized traditional morphological metrics and techniques, including linear and angular measurements as well as Fourier (outline shape) analyses. Phenetic discrimination revealed considerable overlap among the recognized species in the morphospace, as well as a fairly low discriminatory power between species when compared as a group using a step\u2010wise canonical variate analysis. Step\u2010wise discriminant analyses between species pairs gave rise to much higher classification rates, suggesting that different characters are important for distinguishing between different species pairs. Our results also indicate that single individuals and small sample sizes of Buchia specimens are insufficient for biostratigraphic discrimination (unless other rarely preserved features such as the hinge and bysuss ear are available) and that a number of previously described species variants may not be taxonomically valid. A biolog using the multivariate axis that best discriminates between species (CV1) and a random walk\u2010based test using a Hurst estimate analysis indicate a gradualistic evolutionary mode for the Buchia species of Grassy Island. Shell shape and size of buchiids do not appear to be closely tied to lithofacies changes over the c. 10 myr time interval, suggesting that ecophenotypic variation (as it relates to substrate changes) probably had minimal influence on morphology.", "keyphrases": ["evolutionary mode", "buchia", "grassy island"]}
{"id": "10.1017/qua.2018.84", "title": "A review of climate reconstructions from terrestrial climate archives covering the first millennium AD in northwestern Europe", "abstract": "Abstract Large changes in landscape, vegetation, and culture in northwestern (NW) Europe during the first millennium AD seem concurrent with climatic shifts. Understanding of this relation requires high-resolution palaeoclimate reconstructions. Therefore, we compiled available climate reconstructions from sites across NW Europe (extent research area: 10\u00b0W\u201320\u00b0E, 45\u00b0\u201360\u00b0N) through review of literature and the underlying data, to identify supraregional climatic changes in this region. All reconstructions cover the period from AD 1 to 1000 and have a temporal resolution of \u226450 yr. This resulted in 22 climate reconstructions/proxy records based on different palaeoclimate archives: chironomids (1), pollen (6), Sphagnum mosses (1), stalagmites (8), testate amoebae (4), and tree rings (2). Comparing all temperature reconstructions, we conclude that summer temperatures between AD 1 and 250 were relatively high, and the period between AD 250 and 700 was characterised by colder summer conditions. The period from AD 700 to 1000 was again characterised by warmer summers. These temperature shifts occurred in the whole of NW Europe. In contrast, the compilation of precipitation reconstructions does not show a common pattern across NW Europe either as a result of a heterogeneous precipitation pattern or the lack of suitable and consistent precipitation proxies.", "keyphrases": ["climate reconstruction", "europe", "proxy record"]}
{"id": "paleo.005270", "title": "Diversity of tissues in acanthodians with Nostolepis-type histological structure", "abstract": "Acanthodian scales with Nostolepis-type histological structure are separated into five groups based on the presence/absence and extent of stranggewebe, odontocytic and syncitial mesodentine networks, cellular unipolar mesodentine, bone-like mesodentine and durodentine in scale crowns. Two new families of acanthodians are erected, based primarily on histological structure of scales: the Vesperaliidae (stranggewebe extending throughout the scale crown) and the Acritolepidae (bone-like mesodentine in the scale crown). The latter family includes species erected for articulated fish. The families Tchunacanthidae and Lenacanthidae are united in the single family Tchunacanthidae, characterized by having scale crowns with mesodentine formed mainly by unipolar cells. A sixth group, which we exclude from the Nostolepis-type, has scale crowns composed of dentine without lacunae, plus durodentine, and bases with only rare osteocyte cavities. The new groups promote the revision and reassignment of many \"nostolepid\" taxa, in particular removing many species from the genus Nostolepis. Four new genera are erected: Pechoralepis (including part of Nostolepis), assigned to Acritolepidae nov.; and three genera assigned to an indeterminate family, which scales are composed of only odontocytic mesodentine without stranggewebe: Nostovicina (including part of Nostolepis), Nobilesquama (including part of Nostolepis), and Peregrinosquama (including part of Watsonacanthus). Histological structures are considered the primary characters of taxonomical value when based on isolated scales. Unfortunately, scale histology is unknown for most articulated acanthodians.", "keyphrases": ["tissue", "acanthodians", "nostolepis-type histological structure", "mesodentine"]}
{"id": "paleo.000678", "title": "Males Resemble Females: Re-Evaluating Sexual Dimorphism in Protoceratops andrewsi (Neoceratopsia, Protoceratopsidae)", "abstract": "Background Protoceratops andrewsi (Neoceratopsia, Protoceratopsidae) is a well-known dinosaur from the Upper Cretaceous of Mongolia. Some previous workers hypothesized sexual dimorphism in the cranial shape of this taxon, using qualitative and quantitative observations. In particular, width and height of the frill as well as the development of a nasal horn have been hypothesized as potentially sexually dimorphic. Methodology/Principal Findings Here, we reassess potential sexual dimorphism in skulls of Protoceratops andrewsi by applying two-dimensional geometric morphometrics to 29 skulls in lateral and dorsal views. Principal Component Analyses and nonparametric MANOVAs recover no clear separation between hypothetical \u201cmales\u201d and \u201cfemales\u201d within the overall morphospace. Males and females thus possess similar overall cranial morphologies. No differences in size between \u201cmales\u201d and \u201cfemales\u201d are recovered using nonparametric ANOVAs. Conclusions/Significance Sexual dimorphism within Protoceratops andrewsi is not strongly supported by our results, as previously proposed by several authors. Anatomical traits such as height and width of the frill, and skull size thus may not be sexually dimorphic. Based on PCA for a data set focusing on the rostrum and associated ANOVA results, nasal horn height is the only feature with potential dimorphism. As a whole, most purported dimorphic variation is probably primarily the result of ontogenetic cranial shape changes as well as intraspecific cranial variation independent of sex.", "keyphrases": ["sexual dimorphism", "neoceratopsia", "protoceratopsidae"]}
{"id": "paleo.012757", "title": "Habitat suitability and the genetic structure of human populations during the Last Glacial Maximum (LGM) in Western Europe", "abstract": "Human populations in Western Europe during the Last Glacial Maximum were geographically constrained to glacial refugia by the severity of the climate and ecological risk factors. In this research we use an agent-based model of human mobility and interaction, based on ethnographic and archaeological data, to explore the impact of ecological risk on human population structure via a reconstructed landscape of habitat suitability. The agent-based model allows us to evaluate the size and location of glacial refugia, the size of the populations occupying them and the degree of genetic relatedness between people occupying these areas. To do this, we model the probability of an agent foraging groups\u2019 survival as a function of habitat suitability. The model\u2019s simulated \u201cgenomes\u201d (composed of regionally specific genetic markers) allow us to track long-term trends of inter-regional interaction and mobility. The results agree with previous archaeological studies situating a large glacial refugium spanning southern France and northeastern Spain, but we expand on those studies by demonstrating that higher rates of population growth in this central refugium led to continuous out-migration and therefore genetic homogeneity across Western Europe, with the possible exception of the Italian peninsula. These results concur with material culture data from known archaeological sites dating to the Last Glacial Maximum and make predictions for future ancient DNA studies.", "keyphrases": ["human population", "glacial maximum", "refugia", "survival", "habitat suitability"]}
{"id": "10.1126/sciadv.abe7377", "title": "The trilobite upper limb branch is a well-developed gill", "abstract": "The trilobite upper limb branch served as a gill, resolving a long-standing debate about its function. Whether the upper limb branch of Paleozoic \u201cbiramous\u201d arthropods, including trilobites, served a respiratory function has been much debated. Here, new imaging of the trilobite Triarthrus eatoni shows that dumbbell-shaped filaments in the upper limb branch are morphologically comparable with gill structures in crustaceans that aerate the hemolymph. In Olenoides serratus, the upper limb\u2019s partial articulation to the body via an extended arthrodial membrane is morphologically comparable to the junction of the respiratory book gill of Limulus and differentiates it from the typically robust exopod junction in Chelicerata or Crustacea. Apparently limited mechanical rotation of the upper branch may have protected the respiratory structures. Partial attachment of the upper branch to the body wall may represent an intermediate state in the evolution of limb branch fusion between dorsal attachment to the body wall, as in Radiodonta, and ventral fusion to the limb base, as in extant Euarthropoda.", "keyphrases": ["upper limb branch", "gill", "filament"]}
{"id": "paleo.005746", "title": "Life History of Rhamphorhynchus Inferred from Bone Histology and the Diversity of Pterosaurian Growth Strategies", "abstract": "Background Rhamphorhynchus from the Solnhofen Limestones is the most prevalent long tailed pterosaur with a debated life history. Whereas morphological studies suggested a slow crocodile-like growth strategy and superprecocial volant hatchlings, the only histological study hitherto conducted on Rhamphorhynchus concluded a relatively high growth rate for the genus. These controversial conclusions can be tested by a bone histological survey of an ontogenetic series of Rhamphorhynchus. Methodology/Principal Findings Our results suggest that Bennett's second size category does not reflect real ontogenetic stage. Significant body size differences of histologically as well as morphologically adult specimens suggest developmental plasticity. Contrasting the \u2018superprecocial hatchling\u2019 hypothesis, the dominance of fibrolamellar bone in early juveniles implies that hatchlings sustained high growth rate, however only up to the attainment of 30\u201350% and 7\u201320% of adult wingspan and body mass, respectively. The early fast growth phase was followed by a prolonged, slow-growth phase indicated by parallel-fibred bone deposition and lines of arrested growth in the cortex, a transition which has also been observed in Pterodaustro. An external fundamental system is absent in all investigated specimens, but due to the restricted sample size, neither determinate nor indeterminate growth could be confirmed in Rhamphorhynchus. Conclusions/Significance The initial rapid growth phase early in Rhamphorhynchus ontogeny supports the non-volant nature of its hatchlings, and refutes the widely accepted \u2018superprecocial hatchling\u2019 hypothesis. We suggest the onset of powered flight, and not of reproduction as the cause of the transition from the fast growth phase to a prolonged slower growth phase. Rapidly growing early juveniles may have been attended by their parents, or could have been independent precocial, but non-volant arboreal creatures until attaining a certain somatic maturity to get airborne. This study adds to the understanding on the diversity of pterosaurian growth strategies.", "keyphrases": ["rhamphorhynchus", "pterosaurian growth strategy", "hatchling", "life history"]}
{"id": "10.5194/bg-10-7927-2013", "title": "Evidence from \"K\u00f6ppen signatures\" of fossil plant assemblages for effective heat transport of Gulf Stream to subarctic North Atlantic during Miocene cooling", "abstract": "Shallowing of the Panama Sill and the closure of the Central American Seaway initiated the modern Loop Current\u2013Gulf Stream circulation pattern during the Miocene, but no direct evidence has yet been provided for effective heat transport to the northern North Atlantic during that time. Climatic signals from 11 precisely dated plant-bearing sedimentary rock formations in Iceland, spanning 15\u20130.8 million years (Myr), resolve the impacts of the developing Miocene global thermohaline circulation on terrestrial vegetation in the subarctic North Atlantic region. \"Koppen signatures\" were implemented to express climatic properties of fossil plant taxa and their potential modern analogues using the principal concept of the generic Koppen\u2013Geiger climate system, which is based on plant distribution patterns. Using Koppen signatures and the correlation between Koppen climate zones and major global vegetation zones, fossil assemblages were used to trace major vegetation shifts. This evidence was combined with evidence from tectonics and palaeoceanography. In contrast to the global climatic trend, the vegetation record reveals no cooling between ~ 15 and 12 Myr, whereas periods of climatic deterioration between 12 and 10 Myr, 8 and 4 Myr, and in the Pleistocene are in phase with increased pulses of ice-rafted debris in the Northern Hemisphere. The observed sequence of climate change in the northern North Atlantic can most likely be explained by an effective Gulf Stream-mediated heat transport from the middle Miocene onwards.", "keyphrases": ["effective heat transport", "north atlantic", "miocene"]}
{"id": "10.1073/pnas.1212997109", "title": "The Miocene mammal Necrolestes demonstrates the survival of a Mesozoic nontherian lineage into the late Cenozoic of South America", "abstract": "The early Miocene mammal Necrolestes patagonensis from Patagonia, Argentina, was described in 1891 as the only known extinct placental \u201cinsectivore\u201d from South America (SA). Since then, and despite the discovery of additional well-preserved material, the systematic status of Necrolestes has remained in flux, with earlier studies leaning toward placental affinities and more recent ones endorsing either therian or specifically metatherian relationships. We have further prepared the best-preserved specimens of Necrolestes and compared them with newly discovered nontribosphenic Mesozoic mammals from Argentina; based on this, we conclude that Necrolestes is related neither to marsupials nor placentals but is a late-surviving member of the recently recognized nontherian clade Meridiolestida, which is currently known only from SA. This conclusion is supported by a morphological phylogenetic analysis that includes a broad sampling of therian and nontherian taxa and that places Necrolestes within Meridiolestida. Thus, Necrolestes is a remnant of the highly endemic Mesozoic fauna of nontribosphenic mammals in SA and extends the known record of meridiolestidans by almost 45 million years. Together with other likely relictual mammals from earlier in the Cenozoic of SA and Antarctica, Necrolestes demonstrates the ecological diversity of mammals and the mosaic pattern of fauna replacement in SA during the Cenozoic. In contrast to northern continents, the Cenozoic faunal history of SA was characterized by a long period of interaction between endemic mammalian lineages of Mesozoic origin and metatherian and eutherian lineages that probably dispersed to SA during the latest Cretaceous or earliest Paleocene.", "keyphrases": ["necrolestes", "cenozoic", "south america"]}
{"id": "10.1080/14772019.2014.960486", "title": "Earliest known European mammals: a review of the Morganucodonta from Saint-Nicolas-de-Port (Upper Triassic, France)", "abstract": "The Rhaetian locality of Saint-Nicolas-de-Port (France) has yielded the most abundant and diverse mammalian assemblage known from the Late Triassic. Most of the material remains undescribed. We review here the morganucodonts from Saint-Nicolas-de-Port. We identify the upper and lower molariforms of the genus Brachyzostrodon. We also identify in the site Morganucodon peyeri, previously known from the Late Triassic of Hallau (Switzerland), as well as the genera Paceyodon and Paikasigudodon. The description of the new species Megazostrodon chenali sp. nov. extends the stratigraphical and geographical range of the genus, previously known from the Early Jurassic of southern Africa. Finally, another new morganucodont, Rosierodon anceps gen. et sp. nov., is described. The Morganucodonta is recognized as the most diverse order of Late Triassic mammals. Current fossil data suggest that Europe was the centre of initial diversification of morganucodonts at the end of the Triassic, and that morganucodonts were not much affected by the extinction event at the Triassic/Jurassic transition. http://zoobank.org/urn:lsid:zoobank.org:pub:0D30F723-7D65-49B7-8375-BF916BFA0BBA", "keyphrases": ["morganucodonta", "saint-nicolas-de-port", "france"]}
{"id": "10.1126/science.1252243", "title": "Sustained miniaturization and anatomical innovation in the dinosaurian ancestors of birds", "abstract": "Turning large dinosaurs into small birds Most paleontologists agree that birds are descended from dinosaurs. How did such large terrestrial or aquatic animals evolve into small feathered fliers? Lee et al. used two large databases of theropod morphology to explore possible evolutionary patterns that may have driven this dramatic transformation (see the Perspective by Benton). They found no clear pattern of miniaturization across the entire clade of Theropoda. However, several lines of evidence suggested that the lineage leading to birds underwent sustained miniaturization. Within that lineage, body sizes decreased and species evolved faster. They also developed ecological and morphological innovations linked to smaller body sizes. Science, this issue p. 562; see also p. 508 Birds evolved from their dinosaurian ancestors through a period characterized by sustained and repeated decreases in size. [Also see Perspective by Benton] Recent discoveries have highlighted the dramatic evolutionary transformation of massive, ground-dwelling theropod dinosaurs into light, volant birds. Here, we apply Bayesian approaches (originally developed for inferring geographic spread and rates of molecular evolution in viruses) in a different context: to infer size changes and rates of anatomical innovation (across up to 1549 skeletal characters) in fossils. These approaches identify two drivers underlying the dinosaur-bird transition. The theropod lineage directly ancestral to birds undergoes sustained miniaturization across 50 million years and at least 12 consecutive branches (internodes) and evolves skeletal adaptations four times faster than other dinosaurs. The distinct, prolonged phase of miniaturization along the bird stem would have facilitated the evolution of many novelties associated with small body size, such as reorientation of body mass, increased aerial ability, and paedomorphic skulls with reduced snouts but enlarged eyes and brains.", "keyphrases": ["miniaturization", "anatomical innovation", "dinosaurian ancestor", "small body size", "skull"]}
{"id": "10.2307/2992086", "title": "Quaternary history of deciduous forests of eastern North America and Europe", "abstract": "The temperate deciduous forest of North America is more diverse than the deciduous forest of western Europe. This difference has traditionally been explained by greater survival in North America of deciduous species during the Quaternary. More recent investigations have shown, however, that late-Tertiary forests of Europe had already become dominated by conifers, with deciduous angiosperms a minor component. During the Quaternary, coniferous species and genera were lost from the European flora, leaving a few species and genera of angiosperms as the dominant trees. Cold, dry, continental climate during the glaciations caused the extinction of conifers; deciduous trees apparently survived these climatic conditions in pockets of favorable habitat in the eastern Mediterranean region. In eastern North America, in contrast, temperate deciduous forests are quite similar to the forests that were present in the late Tertiary. During the Quaternary, relatively few extinctions occurred, although deciduous angiosperms were displaced from the Appalachian mountains, surviving in small populations in the lower Mississippi valley or on the southern coastal plain. Coniferous forests dominated by spruce grew in the Great Plains, and forests dominated by pine grew on the southern part of the Atlantic coastal plain. At the opening of the Holocene, and presumably at the beginning of all the previous interglacials, tree distributions changed dramatically as temperate species rapidly extended their ranges northward. Range boundaries have continued to change throughout the Holocene, as expansions and contractions of range have occurred as the result of climatic change. Quaternary climatic history caused dramatic changes in the forests of both areas, indicating that modern species distributions can no longer be considered relicts of Tertiary distributions. Throughout the Quaternary, species ranges have changed in response to changes in regional climate; many forest communities are of recent origin, having received their present complements of tree species within the last 5,000 years. Forest communities in Eastern North America and in Western Europe as well have been invaded repeatedly during the Holocene by forest species expanding from refuges far to the south. Temperate deciduous forest grows over a wide area of eastern North America. The forest is rich in numbers of species, especially the mixed mesophytic forest communities of the southern Appalachians. These forests were traditionally compared with forests of the Tertiary Period (Reid, 1935; Braun, 1947, 1950; Campbell, 1982), when the so-called Arcto-Tertiary geoflora was supposed to have been widespread throughout the northern hemisphere (Chaney, 1944). Reid (1935) and Chaney (1944) believed that severe climate during the Quaternary Period eliminated the Arcto-Tertiary geoflora entirely from many regions, such as western North America, while in others, such as western Europe, extinctions eliminated all but a few species and genera. The modern deciduous forests were thus seen as remnants of an originally widespread, uniform vegetation. The geoflora concept has been challenged recently by Wolfe (1978, 1979) who argued that a uniform broad-leaved forest never existed. His analysis of the paleobotanical data shows that Tertiary floras were diverse, with evergreen gymnosperms such as Sequoia dominant in some regions, and evergreen angiosperms present elsewhere. He argued that a number of major climatic changes occurred during the Tertiary, especially during the Oligocene; these changes led to local changes in abundances of various components of the Tertiary flora. Thus changes of climate caused local adaptations rather than migrations of intact plant communities from one latitude to another as Chaney hypothesized (Wolfe, 1979). Before the end of the Tertiary Period, the forests of western United States were already dominated by conifers. A similar change had also occurred in Europe, where Pliocene floras contained many genera and species of conifers (Wolfe, 1979). Sequoia was the dominant tree in some regions (Traverse, 1982). Mixed coniferous-deciduous forest in Europe during the Pliocene is a new interpretation of forest history that stands in marked contrast to the traditional view. The traditional view held that deciduous forest persisted in Europe into the early Quaternary Period, when increasing se1 This work was supported by the National Science Foundation. 2 Department of Ecology and Behavioral Biology, University of Minnesota, Minneapolis, Minnesota 55455. ANN. MISSOURI BOT. GARD. 70:550-563. 1983. This content downloaded from 157.55.39.181 on Thu, 29 Sep 2016 05:51:40 UTC All use subject to http://about.jstor.org/terms 1983] DAVIS-QUATERNARY HISTORY 551 verity of climate caused extinctions of many angiosperm trees (Tralau, 1973; Campbell, 1982). In contrast, Wolfe emphasized that coniferous species and genera were the important losses from the European flora during the Quaternary. The Taxodiaceae, for example, once so important in the Black Sea region, were eliminated entirely (Traverse, 1982). The angiospermous genera that remain today represent differential survival of one component of what had been mixed coniferous-deciduous forest (Wolfe, 1979). Wolfe pointed out that Europe today has the type of climatic regime that elsewhere in the world supports mixed coniferous forest; the dominance of deciduous species in the region today is therefore anomalous. Eastern North America, in contrast, has a climatic regime typical of deciduous forest regions. Today it supports forests dominated by deciduous angiosperms, just as it did during the late Tertiary (Wolfe, 1979). The Quaternary pollen record adds a useful perspective to these differing views of the origin of the European deciduous forest and the relationship of deciduous forests in eastern North America and Europe. First, the Quaternary record shows that dramatic changes in the geographical ranges of forest species occurred during the Quaternary. We can no longer speak of Tertiary forest \"remaining\" in a region throughout the Quaternary, because many tree species were repeatedly displaced during the Quaternary from the geographical region where they now occur. For this reason, modern geographical ranges cannot be used to identify the locations of \"relict\" Tertiary forests. Second, the response of temperate forest trees to Quaternary climatic change was individualistic, supporting Wolfe's contention that Tertiaryfloras would not have migrated as units in response to climatic events. Third, the extinctions that occurred during the Quaternary, especially the differential extinctions of conifers and deciduous angiosperms document that the differential severity of Quaternary climate affectedforests differently in Europe and North America. These three factors contributed to the makeup of the modem temperate forest floras of North America and Europe. In considering how Quaternary climate changed Pliocene floras into modem floras, the two phases of Quaternary climate, glacial climates and interglacial climates, are important. The two phases appear to have had quite different effects. -Glacial phases, i.e., times when ice sheets were more extensive than at present, comprised about 90 percent of the time during the Quaternary period. During these long, cold intervals, temperate species survived in small populations that were susceptible to extinction. The severity of the climate, both in terms of average temperature, continentality, and drought; the extent of geographical displacement of plant species; the sizes of populations; and the community composition of forests in refuge areas; all had an effect on the probability of extinction for individual species. Interglacial intervals comprised a much smaller proportion (about 10 percent) of the Quaternary period. They were characterized by climates similar to those of today, which in Europe and eastern North America seem to bear a general resemblance to late-Tertiary climate. Each interglacial was short, lasting only 10,000 to 1 5,000 years, and began and ended with a sudden, major climatic change (Emiliani, 1972; Broecker & Van Donk, 1970). The interglacials, although favorable for survival and population expansion of temperate forest trees both in Europe and eastern North America, were times of vegetational instability. During interglacials the geographical distributions of temperate species shifted many hundreds of kilometers, and the composition of forest comunities changed rapidly. GEOLOGICAL EVIDENCE OF EVENTS DURING THE QUATERNARY PERIOD The exploration of the deep sea by geologists in the last twenty years has led to a new understanding of Quaternary events, revolutionizing our thinking about the time scale of glaciation. Many marine cores include sediment extending through the entire Quaternary Period. Previously, four major glaciations were recognized within the Quaternary. We now know that there were 18 or 20 glaciations during the last 2 million years, the time interval now assigned to the Quaternary. Each of these glacial cycles lasted about 100,000 years (Hays et al., 1969). Figure 1 shows oxygen-isotope paleoclimatic records for the last 800,000 years. The climatic events are well dated: the last interglacial (the earliest part of stage 5) started 125,000 years ago, lasted about 15,000 years, and ended with a sharp decline in temperature that initiated the last glaciation. Warm conditions returned, followed by a cold period, then a short warm interval. Seventy thousand years ago a long cold interval (stages 2-4) began, which culminated in the glacial maximum 18,000 to 20,000 years ago (Broecker & Van Donk, 1970). This content downloaded from 157.55.39.181 on Thu, 29 Sep 2016 05:51:40 UTC All use subject to http://about.jstor.org/terms 552 ANNALS OF THE MISSOURI BOTANICAL GARDEN [VOL. 70", "keyphrases": ["deciduous forest", "eastern north america", "climatic change"]}
{"id": "paleo.006830", "title": "Synapsid tracks with skin impressions illuminate the terrestrial tetrapod diversity in the earliest Permian of equatorial Pangea", "abstract": "Lower Permian deposits of the Boskovice Basin in the Czech Republic have long been renowned for extraordinarily abundant specimens of discosauriscid seymouriamorphs, some of which showing exceptional preservation, including widespread soft tissues. The only other tetrapods from the strata are represented by rare temnospondyls. However, recent fieldwork in the Asselian (lowermost Permian) of the Boskovice Basin has yielded a diverse assemblage of tetrapod tracks, illuminating a hidden terrestrial tetrapod diversity. Here, we describe well-preserved isolated tracks, manus-pes couples, and a slab with trackways composed of approximately 20 tracks in at least four different directions belonging to early-diverging, or \u2018pelycosaur-grade\u2019, synapsids. The material originates from three localities situated within the Letovice and Padochov formations and is assignable to the ichnotaxon Dimetropus. The best-preserved specimen further shows rare skin impressions, which have not been observed from the hands or feet of early-diverging mammal-line amniotes before. The new material adds to the scarce record of synapsids from the Carboniferous/Permian transitional interval of equatorial Pangea. At the same time, it highlights the significance of the ichnological record of the Boskovice Basin which has long been neglected despite offering evidence for the presence of diverse faunal components that have not been reported from these basinal deposits before.", "keyphrases": ["skin impression", "terrestrial tetrapod diversity", "pangea", "temnospondyls", "faunal component"]}
{"id": "10.1073/pnas.0806314106", "title": "Two-phase increase in the maximum size of life over 3.5 billion years reflects biological innovation and environmental opportunity", "abstract": "The maximum size of organisms has increased enormously since the initial appearance of life >3.5 billion years ago (Gya), but the pattern and timing of this size increase is poorly known. Consequently, controls underlying the size spectrum of the global biota have been difficult to evaluate. Our period-level compilation of the largest known fossil organisms demonstrates that maximum size increased by 16 orders of magnitude since life first appeared in the fossil record. The great majority of the increase is accounted for by 2 discrete steps of approximately equal magnitude: the first in the middle of the Paleoproterozoic Era (\u22481.9 Gya) and the second during the late Neoproterozoic and early Paleozoic eras (0.6\u20130.45 Gya). Each size step required a major innovation in organismal complexity\u2014first the eukaryotic cell and later eukaryotic multicellularity. These size steps coincide with, or slightly postdate, increases in the concentration of atmospheric oxygen, suggesting latent evolutionary potential was realized soon after environmental limitations were removed.", "keyphrases": ["maximum size", "innovation", "cell"]}
{"id": "paleo.010225", "title": "Identifying Archaeological Bone via Non-Destructive ZooMS and the Materiality of Symbolic Expression: Examples from Iroquoian Bone Points", "abstract": "Today, practical, functional and symbolic choices inform the selection of raw materials for worked objects. In cases where we can discern the origin of worked bone, tooth, ivory and antler objects in the past, we assume that similar choices are being made. However, morphological species identification of worked objects is often impossible due to the loss of identifying characteristics during manufacture. Here, we describe a novel non-destructive ZooMS (Zooarchaeology by Mass Spectrometry) method which was applied to bone points from Pre-Contact St. Lawrence Iroquoian village sites in southern Quebec, Canada. The traditional ZooMS technique requires destructive analysis of a sample, which can be problematic when dealing with artefacts. Here we instead extracted proteins from the plastic bags in which the points had been stored. ZooMS analysis revealed hitherto unexpected species, notably black bear (Ursus americanus) and human (Homo sapiens sapiens), used in point manufacture. These surprising results (confirmed through genomic sequencing) highlight the importance of advancing biomolecular research in artefact studies. Furthermore, they unexpectedly and exceptionally allow us to identify and explore the tangible, material traces of the symbolic relationship between bears and humans, central to past and present Iroquoian cosmology and mythology.", "keyphrases": ["non-destructive zooms", "bone point", "protein"]}
{"id": "10.1002/spp2.1238", "title": "Caspary's fungi from Baltic amber: historic specimens and new evidence", "abstract": "Amber is a valuable source of Mesozoic and Cenozoic fossil fungi. The earliest amber\u2010preserved fungi were described in the nineteenth and early twentieth centuries from Eocene Baltic amber. In 1907, Richard Klebs summarized the legacy of Robert Caspary based on his specimens, research notes and publications. This treatise contains descriptions and illustrations of 13 morphologies of fossil fungi which have not been investigated since. We managed to locate six of Caspary's amber specimens and imaged and re\u2010investigated the fossil fungi within. We provide amended descriptions of these six specimens, select new specimens from historic and recent collections which are probably conspecific with five fossils that appear to have been lost, and finally also describe and evaluate five newly found fossil fungi from Baltic amber. The fungi belong to the phylum Ascomycota (Subkingdom Dikarya). Only two of Caspary's fungi can be confidently assigned to modern genera, Metacapnodium (Metacapnodiaceae) and Calicium (Caliciaceae). The new combination Calicium succini (Caspary) Rikkinen & A. R. Schmidt is made. The fossils originally placed in Acremonium, Cetraria, Gonatobotrys, Ramularia, Stilbum and Torula cannot be assigned to these genera, and should not be used as minimum age constrains for the respective lineages.", "keyphrases": ["baltic amber", "fungus", "caspary"]}
{"id": "10.1002/oa.662", "title": "Trophic Level Isotopic Enrichment of Carbon and Nitrogen in Bone Collagen: Case Studies from Recent and Ancient Terrestrial Ecosystems", "abstract": "Prey-predator collagen enrichment values for carbon and nitrogen isotopic compositions are investigated. New enrichment values are given for the well-monitored ecosystem of Bialowieza primeval forest (Poland) for lynx and wolf. The impact of using different approximations in calculating such enrichment values is discussed. Several case studies of ancient vertebrate communities from Upper Palaeolithic sites in southwestern France are presented to check whether the enrichment values estimated for these past ecosystems are consistent with those measured in well-monitored modern ecosystems. The use of ranges of values rather than average ones is recommended, tentatively 0 to 2\u2030 for \u03b413C and 3 to 5\u2030 for \u03b415N. Copyright \u00a9 2003 John Wiley & Sons, Ltd.", "keyphrases": ["carbon", "bone collagen", "case study", "trophic level"]}
{"id": "paleo.011295", "title": "Digital restoration of the pectoral girdles of two Early Cretaceous birds and implications for early-flight evolution", "abstract": "The morphology of the pectoral girdle, the skeletal structure connecting the wing to the body, is a key determinant of flight capability, but in some respects is poorly known among stem birds. Here, the pectoral girdles of the Early Cretaceous birds Sapeornis and Piscivorenantiornis are reconstructed for the first time based on computed tomography and three-dimensional visualization, revealing key morphological details that are important for our understanding of early-flight evolution. Sapeornis exhibits a double articulation system (widely present in non-enantiornithine pennaraptoran theropods including crown birds), which involves, alongside the main scapula-coracoid joint, a small subsidiary joint, though variation exists with respect to the shape and size of the main and subsidiary articular contacts in non-enantiornithine pennaraptorans. This double articulation system contrasts with Piscivorenantiornis in which a spatially restricted scapula-coracoid joint is formed by a single set of opposing articular surfaces, a feature also present in other members of Enantiornithines, a major clade of stem birds known only from the Cretaceous. The unique single articulation system may reflect correspondingly unique flight behavior in enantiornithine birds, but this hypothesis requires further investigation from a functional perspective. Our renderings indicate that both Sapeornis and Piscivorenantiornis had a partially closed triosseal canal (a passage for muscle tendon that plays a key role in raising the wing), and our study suggests that this type of triosseal canal occurred in all known non-euornithine birds except Archaeopteryx, representing a transitional stage in flight apparatus evolution before the appearance of a fully closed bony triosseal canal as in modern birds. Our study reveals additional lineage-specific variations in pectoral girdle anatomy, as well as significant modification of the pectoral girdle along the line to crown birds. These modifications produced diverse pectoral girdle morphologies among Mesozoic birds, which allowed a commensurate range of capability levels and styles to emerge during the early evolution of flight.", "keyphrases": ["pectoral girdle", "early-flight evolution", "sapeornis"]}
{"id": "10.1080/02724634.1992.10011474", "title": "The stapes of Lambdopsalis bulla (Multituberculata) and transformational analyses on some stapedial features in Mammaliaformes", "abstract": "ABSTRACT The stapes of the Paleocene multituberculate Lambdopsalis bulla, recovered from a unique intra-vestibuli circumstance, is small and columelliform. It has a slim shaft, a slit-like stapedial foramen, a distinct head, and a well-developed, nearly circular footplate. With new evidence of the stapes from Lambdopsalis bulla and those reported recently from Sinoconodon, Haldanodon, and Pachygenelus, stapedial characters are analyzed in a selected group consisting of Placentalia, Marsu-pialia, Monotremata, Multituberculata, Morganucodontidae, Sinoconodon, Haldanodon, and the tritheledontid Pachygenelus. Stapedial characters discussed include relative size of the stapes, shape of the stapes, development of stapedial footplate, shape of the stapedial footplate, the stapedial foramen, position of the stapedial artery, and orientation of the stapes. Conclusions are: 1) the relative size of the stapes does not differentiate multituberculates from morganucodontids; 2) stapes are divided into three basic types...", "keyphrases": ["stape", "lambdopsalis bulla", "multituberculata"]}
{"id": "paleo.013037", "title": "Palaeontological Evidence for the Last Temporal Occurrence of the Ancient Western Amazonian River Outflow into the Caribbean", "abstract": "Fossil catfishes from fluvio-lacustrine facies of late Miocene Urumaco, early Pliocene Castilletes and late Pliocene San Gregorio formations provide evidence of a hydrographic connection in what is today desert regions of northern Colombia and Venezuela. New discoveries and reevaluation of existing materials leads to the recognition of two new records of the pimelodid Brachyplatystoma cf. vaillantii, and of three distinct doradid taxa: Doraops sp., Rhinodoras sp., and an unidentified third form. The presence of fossil goliath long-whiskered catfishes and thorny catfishes are indicative of the persistence of a fluvial drainage system inflow into the South Caribbean during the Pliocene/Pleistocene boundary, complementary to the previous western Amazonian hydrographic system described from the Middle Miocene Villavieja Formation in central Colombia and Late Miocene Urumaco Formation in northwestern Venezuela. The Pliocene Castilletes and San Gregorio formations potentially represent the last lithostratigraphic units related with an ancient western Amazonian fish fauna and that drainage system in the Caribbean. Alternatively, it may preserve faunas from a smaller, peripheral river basin that was cut off earlier from the Amazon-Orinoco, today found in the Maracaibo basin and the Magdalena Rivers.", "keyphrases": ["caribbean", "hydrographic system", "vertebrate fauna", "turtle", "south america"]}
{"id": "10.5194/cp-6-461-2010", "title": "Mid-Tertiary paleoenvironments in Thailand: pollen evidence", "abstract": "Abstract. Only few well-dated records document the evolution of Southeast Asian paleoenvironments during the Cenozoic. Here we analyse continental pollen assemblages from Late Oligocene and Miocene fossil sites of Thailand. In agreement with previous studies, palynoflora from the Oligocene suggests warm temperate forested habitats at 24\u201326 Ma, whereas Middle Miocene assemblages are made of thermophilous taxa. This change can be linked to the major climate reorganization that brought warmer and wetter conditions over Southeast Asia around 22 Ma. This study also provides the first submillional records from the Middle Miocene of Thailand. Thirteen samples of lignite layers from the sivaladapid-bearing Mae Moh site, dated between 13.3 and 13.1 Ma, and six samples from the hominoid-bearing Chiang Muan deposit, dated between 12.4 and 12.2 Ma, document oscillations between tropical woodlands and grasslands in northern Thailand. These pollen records likely reflect climate variations linked to insolation variations. Late Miocene palynological assemblages from Khorat, northeastern Thailand, document fluviolacustrine paleoenvironments alternatively covered by thermophilous trees and grasslands. These records show that both sivaladapids and early hominoids from Thailand have evolved in tropical environments with high variability in the vegetation cover.", "keyphrases": ["paleoenvironment", "thailand", "pollen record"]}
{"id": "10.1017/S0022336000034946", "title": "A statistical study of Rhamphorhynchus from the Solnhofen Limestone of Germany: Year-classes of a single large species", "abstract": "A statistical and morphological study of the pterosaur Rhamphorhynchus from the Solnhofen Limestone of Germany shows that specimens fall into discrete size-classes that are year-classes resulting from seasonal mortality or preservation of specimens. Taxonomic characters used in the past to separate species of Rhamphorhynchus are all related to size and ontogeny, and all specimens belong to a single species, R. muensteri. Thus, the collections of Rhamphorhynchus provide an unequaled record of the growth and development of a Jurassic rhamphorhynchoid pterosaur. Rhamphorhynchus did not have rapid determinate growth; the growth rate was comparable to that of extant crocodilians, and growth continued over the course of at least three years after individuals began to fly.", "keyphrases": ["solnhofen limestone", "germany", "year-classe", "pterosaur"]}
{"id": "10.1080/14772019.2019.1682696", "title": "New toothed Early Cretaceous ornithuromorph bird reveals intraclade diversity in pattern of tooth loss", "abstract": "The earliest record of the Ornithuromorpha, which includes crown birds, is currently known from the Early Cretaceous Jehol Biota in north-eastern China. Here we describe a new ornithuromorph bird, Mengciusornis dentatus gen. et sp. nov., from the Jiufotang Formation of this biota. Mengciusornis preserves a suite of morphological features exclusively observed among ornithuromorphs in the sympatric taxon Schizooura, including a robust and \u2018V\u2019-shaped furcula with a short hypocleidium, and a humerus with a large, rectangular deltopectoral crest in which the distodorsal corner is distinctively developed into a sharp, angular point. The results of our phylogenetic analysis recover these two species together in a clade, positioned stemward within the Ornithuromorpha. Mengciusornis has toothed premaxillae, in stark contrast with the edentulous jaws of Schizooura, demonstrating that dentition varied considerably between some closely related species. Furthermore, all previously known Jehol ornithuromorphs with toothed premaxillae have an edentulous rostral portion of the element, suggesting that tooth loss in this clade proceeded from the rostral end caudally, whereas in Mengciusornis the premaxilla lacks this edentulous rostral tip although the maxilla and dentary are toothless, indicating that the pattern of tooth loss, not unexpectedly, varied between lineages of ornithuromorphs. This observation suggests a strong degree of plasticity in the developmental mechanisms regulating tooth and beak formation, which is supported by earlier evidence that indicates teeth have been lost multiple times within Aves and Dinosauria. Mengciusornis preserves a ventrally hooked scapular acromion that is convergently evolved in parallel with some enantiornithines and neornithines, providing further evidence of the homoplasy that characterizes avian evolution. http://zoobank.org/urn:lsid:zoobank.org:pub:311B34B9-1CBF-47A6-B821-650C04560137", "keyphrases": ["ornithuromorph bird", "tooth loss", "jiufotang formation"]}
{"id": "10.1080/02724634.2014.904323", "title": "Jaw Mechanics and Evolutionary Paleoecology of Megaherbivorous Dinosaurs from the Dinosaur Park Formation (Upper Campanian) of Alberta, Canada", "abstract": "ABSTRACT \n The question of what role differential jaw mechanics may have played in facilitating dietary niche partitioning among Late Cretaceous megaherbivorous dinosaurs from Laramidia is examined, using the fossil assemblage of the Dinosaur Park Formation as a test case. We use phylogenetic inference to reconstruct the mandibular adductor musculature of these animals, which we then apply to the construction of biomechanical lever models of the mandible to estimate relative bite forces. Our findings reveal predictably weak bite forces in ankylosaurs, and comparatively high bite forces in ceratopsids and hadrosaurids, both of which possessed a mechanical advantage that produced bite forces 2\u20133 times higher than those forces exerted by the adductor musculature. The impressive jaw mechanism shared by the last two taxa evolved in a stepwise fashion, independently in each lineage. There is tentative evidence to suggest that nodosaurids had more powerful bites than ankylosaurids, but the overall mechanical diversity among megaherbivores from the Dinosaur Park Formation is low, suggesting that differential jaw mechanics could have played only a subsidiary role in niche partitioning. Such mechanical conservatism may have may have been selected for, or it may simply reflect the limits imposed by evolutionary constraints. Regardless, mechanical disparity patterns remained stable throughout the \u223c1.5 Ma evolution of the Dinosaur Park Formation megaherbivore chronofauna.", "keyphrases": ["megaherbivorous dinosaur", "dinosaur park formation", "jaw mechanism"]}
{"id": "10.1002/oa.962", "title": "Human mummified brain from a medieval tomb with lime\u2010soil mixture barrier of the Joseon Dynasty, Korea", "abstract": "Although all of the Korean medieval mummies found up to the present time have shown relatively well-preserved brains, relevant biomedical information has been difficult to acquire owing to the obstacles to obtaining permission to conduct invasive investigations. However, recently we were able to secure permission to investigate, through various forms of examination including dissection, a well-preserved brain found in a lime-soil mixture barrier (LSMB) tomb in Yongin, Korea, because the remains found within the tomb were mostly skeletal. As in the cases of mummified brains from tombs found in other countries, the current Yongin case showed well-preserved grey and white matter within well demarcated brain lobes, on which sulci and gyri could be identified. On histological examination, we found that the remaining brain tissue was composed mainly of lipids, which seems to correspond to the preserved myelin sheath. The present paper is the first report on the general preservation status of a mummified brain found in Korea. Moreover, because mummified brains are found quite frequently in LSMB medieval tombs, this study could provide a good basis upon which further such palaeo-neuropathological studies can be progressed. Copyright \u00a9 2008 John Wiley & Sons, Ltd.", "keyphrases": ["brain", "medieval tomb", "korea"]}
{"id": "10.1017/S0022336000032145", "title": "Trilobite malformations and the fossil record of behavioral asymmetry", "abstract": "Malformations of trilobites are classified as healed injuries, teratological conditions, and pathological conditions. An improved method of recognizing such malformations combines information about the conditions under which cell injury can occur, the processes by which animal tissues react to injury, and trilobite morphology. Study of healed injuries of polymeroid trilobites shows that injuries attributed to sublethal predation tend to be most commonly preserved on the pleural lobes, the posterior half of the body, and the right side. Statistically significant differences in the number of predation scars between the right and left sides is interpreted as evidence of right-left behavioral asymmetry in some predators of trilobites or the trilobites themselves. Asymmetrical, or lateralized, behavior in present-day animals is one manifestation of handedness, and is usually related to a functional lateralization of the nervous system. Evidence of behavioral lateralization in some Paleozoic predators or prey suggests that those organisms also possessed lateralized nervous systems. Right-left differences in preserved predation scars on trilobites date from the Early Cambrian (Olenellus Zone), and are the oldest known evidence of behavioral asymmetry in the fossil record. Other examples of structural or behavioral asymmetry from the fossil record of animals are cited. Lateralization is recognized in representatives of the Arthropoda, Annelida, Bryozoa, Echinodermata, Cnidaria, Mollusca, Chordata, and Conodonta, and in trace fossils.", "keyphrases": ["malformation", "behavioral asymmetry", "injury", "trilobite morphology", "predator"]}
{"id": "10.1073/pnas.1616744114", "title": "Genomic evidence reveals a radiation of placental mammals uninterrupted by the KPg boundary", "abstract": "Significance We produced a genome-scale dataset from representatives of all placental mammal orders to infer diversification timing relative to the Cretaceous\u2013Paleogene (KPg) boundary. Our sensitivity analyses show that divergence time estimates within placentals are considerably biased by the specific way in which a given dataset is processed. We examined the performance of various dating approaches using a comprehensive scheme of likelihood analyses and computational simulations, allowing us to identify the optimal molecular clock parameters, gene sets, and gene partitioning schemes for reliable dating. Based on the optimal methodology, we present a hypothesis of mammalian divergence timing that is more consistent with the fossil record than previous molecular clock reconstructions, suggesting that placental mammals underwent a continuous radiation across the KPg boundary. The timing of the diversification of placental mammals relative to the Cretaceous\u2013Paleogene (KPg) boundary mass extinction remains highly controversial. In particular, there have been seemingly irreconcilable differences in the dating of the early placental radiation not only between fossil-based and molecular datasets but also among molecular datasets. To help resolve this discrepancy, we performed genome-scale analyses using 4,388 loci from 90 taxa, including representatives of all extant placental orders and transcriptome data from flying lemurs (Dermoptera) and pangolins (Pholidota). Depending on the gene partitioning scheme, molecular clock model, and genic deviation from molecular clock assumptions, extensive sensitivity analyses recovered widely varying diversification scenarios for placental mammals from a given gene set, ranging from a deep Cretaceous origin and diversification to a scenario spanning the KPg boundary, suggesting that the use of suboptimal molecular clock markers and methodologies is a major cause of controversies regarding placental diversification timing. We demonstrate that reconciliation between molecular and paleontological estimates of placental divergence times can be achieved using the appropriate clock model and gene partitioning scheme while accounting for the degree to which individual genes violate molecular clock assumptions. A birth-death-shift analysis suggests that placental mammals underwent a continuous radiation across the KPg boundary without apparent interruption by the mass extinction, paralleling a genus-level radiation of multituberculates and ecomorphological diversification of both multituberculates and therians. These findings suggest that the KPg catastrophe evidently played a limited role in placental diversification, which, instead, was likely a delayed response to the slightly earlier radiation of angiosperms.", "keyphrases": ["placental mammal", "kpg boundary", "diversification"]}
{"id": "10.1080/09853111.2013.877237", "title": "Spatial distribution of climatic conditions from the Middle Eocene to Late Miocene based on palynoflora in Central, Eastern and Western Anatolia", "abstract": "The continental climatic evolution of Anatolia has been reconstructed quantitatively for the last 45 million years using the coexistence approach. Although there were some regional effects, the Anatolian Cenozoic continental climate record correlated with the European climatic condition and the global oxygen isotope record from marine environments. From middle Eocene to late Miocene, continental warming in Anatolia was pronounced for inferred winter temperature and mean annual temperature as in Europe. Generally, the palaeoclimatic property of Anatolia resembles the European climatic changing and marine temperature changing based on the oxygen isotope record; however, climatic values of the terrestrial area in Anatolia are higher from Lutetian to Aquitanian and these values are lower than European values from Aquitanian to Tortonian. Correspondingly, Cenozoic climatic cooling in Anatolia is directly associated with an increase of seasonality, palaeogeographic position and terrestrial condition. Furthermore, mean annual precipitation values of Anatolia remained relatively stable during the Eocene\u2013Oligocene; however, these values indicated changing throughout middle\u2013late Miocene. Moreover, in this study, decline of abundance and variables for the mangrove and back mangrove palaeocommunities during the last 45 million years is recorded because of the decreasing of humidity, temperature and increasing of terrestrial condition.", "keyphrases": ["climatic condition", "middle eocene", "anatolia"]}
{"id": "10.4404/hystrix-28.2-12048", "title": "Deer in an arid habitat: dental microwear textures track feeding adaptability", "abstract": "Teeth constitute a bridge between an organism and its environment. Dental wear is a good proxy for (paleo) ecologists to better comprehend the ecology and habitat of modern and extinct species. In this study, we showed Dental Microwear Texture Analysis to be a useful tool, integrating not only specific plant selection but also dietary quality and digestibility in order to understand resource use. Resource-partitioning, seasonal and sexual variations in the diet of two deer species on a Spanish game estate are explored here through Dental Microwear Texture Analysis. This Mediterranean area is on the fringes of the average European environments in terms of constraints and diet for extant red and fallow deer, resulting in an opportunity to understand their ability to live in harsh conditions and the feeding strategies they developed. These two taxa already experienced harsh living conditions during the Pleistocene. Dental microwear texture shows both deer feeding differently on the herbaceous layer in a context where it is the main resource consumed annually. These differences are linked to body mass. With its smaller incisor arcade, Dama dama is able to be more selective, hence focusing on less fibrous parts of forages. Cervus elaphus is more plastic, with dietary variations corresponding to seasonal plant availability and the physiological requirements of stags and does. In general, C. elaphus consumes a more fibrous and less digestible vegetable material than D. dama . This study brings light on the feeding behavior of the two game species under constraint conditions. The results of this study are discussed in terms of realized vs potential ecological niche.", "keyphrases": ["dental microwear texture", "tool", "deer"]}
{"id": "paleo.004200", "title": "A new trackway possibly made by a trotting theropod at the Las Hoyas fossil site (Early Cretaceous, Cuenca Province, Spain): Identification, bio-dynamics and palaeoenvironmental implications", "abstract": "Dinosaur footprints have recently been identified at the Las Hoyas fossil site, renewing interest in its trace fossils as aids in the interpretation of the area's palaeoenvironment and palaeocommunity. The varied tetrapod print morphologies found seem to have been influenced by the contemporaneous presence of microbial mats. This paper updates the information on tetrapod traces at the site and describes a new dinosaur trackway containing four tridactyl footprints. Although the trackway is not particularly well-preserved, the morphology of the toe marks, the heel surface, and the general morphology of the prints strongly suggest they were produced by a theropod dinosaur of medium size. Further, the ratio between the stride length and the deduced hip height suggest the trackmaker was trotting. Interestingly, the footprints are very similar in size to the pes of Concavenator, a carcharodontosaurid dinosaur known from skeletal material at the same locality. This new ichnological evidence reveals tetrapod prints to be more abundant toward the top of the site\u02bcs stratigraphic succession. This suggests that, over time, the ecosystem evolved toward more frequent dry periods the dinosaurs present became able to walk in areas with shallow water and big dinosaurs walked across the ponding zone of Las Hoyas. J.J. Moratalla. Instituto Geol\u00f3gico y Minero de Espa\u00f1a (Igme), Museo Geominero, R\u00edos Rosas 23, 28003 Madrid, Spain. j.moratalla@igme.es J. Marug\u00e1n-Lob\u00f3n. Unidad de Paleontolog\u00eda, Universidad Aut\u00f3noma de Madrid, Cantoblanco, 28049 Madrid, Spain and Dinosaur Institute, Natural History Museum of Los Angeles County, Los Angeles, CA, USA. jesus.marugan@uam.es H. Mart\u00edn-Abad. Jurassica Museum, Route de Fontenais 21, 2900 Porrentruy, Switzerland. hugo.martin.abad@gmail.com and Department of Geosciences, University of Fribourg, Chemin du Mus\u00e9e 6, 1700 Fribourg, Switzerland E. Cuesta. Unidad de Paleontolog\u00eda, Universidad Aut\u00f3noma de Madrid, Cantoblanco, 28049 Madrid, Spain. elena.cuesta@uam.es Moratalla, J.J., Marug\u00e1n-Lob\u00f3n, J., Mart\u00edn-Abad, H., Cuesta, E. and Buscalioni, A.D. 2017. A new trackway possibly made by a trotting theropod at the Las Hoyas fossil site (Early Cretaceous, Cuenca Province, Spain): Identification, bio-dynamics, and palaeoenvironmental implications. Palaeontologia Electronica 20.3.59A: 1-14. https://doi.org/10.26879/770 palaeo-electronica.org/content/2017/2073-theropod-trackway-at-las-hoyas Copyright: November 2017 Palaeontological Association. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ MORATALLA ET AL.: THEROPOD TRACKWAY AT LAS HOYAS A.D. Buscalioni. Unidad de Paleontolog\u00eda, Universidad Aut\u00f3noma de Madrid, Cantoblanco, 28049 Madrid, Spain. angela.delgado@uam.es.", "keyphrases": ["trotting theropod", "bio-dynamic", "palaeoenvironmental implication", "succession"]}
{"id": "10.1080/02724634.1987.10011653", "title": "Grades and clades in hornless ruminant evolution: the reality of the Gelocidae and the systematic position of Lophiomeryx and Bachitherium", "abstract": "ABSTRACT The phylogenetic relationships of hornless ruminants are reassessed in light of consideration of the systematic position of the genera Lophiomeryx (previously assigned to the Gelocidae), and Bachitherium (previously assigned to the Leptomerycidae or Hypertragulidae), and the reality of the Gelocidae as a cladistically valid taxon is questioned. It is concluded that Lophiomeryx should be placed in its own family, the Lophiomeryicidae (along with the genera Cryptomeryx and Iberomeryx, previously assigned to the Tragulidae), and that the family forms the sister group to the Pecora. Bachitherium is also best placed in its own family, the Bachitheriidae, forming the sister group to the Pecora plus the Lophiomeryicidae. The Gelocidae cannot be united by any unique character, and are best considered a polyphyletic assemblage of primitive pecorans, from among which the higher pecoran families may be derived.", "keyphrases": ["systematic position", "lophiomeryx", "bachitherium"]}
{"id": "10.1017/S0003598X00088335", "title": "A Levallois point embedded in the vertebra of a wild ass (Equus africanus): hafting, projectiles and Mousterian hunting weapons", "abstract": "The hunting methods of the Neanderthals are rarely evident in detail in the archaeological record. Here, the rare and important discovery of a fragment of broken Levallois point, embedded in the neck-bones of a wild ass, provokes plenty of discussion of the methods of hafting and killing game in the Middle Palaeolithic of Syria.", "keyphrases": ["levallois point", "hafting", "weapon"]}
{"id": "paleo.000480", "title": "Unveiling biases in soft\u2010tissue phosphatization: extensive preservation of musculature in the Cretaceous (Cenomanian) polychaete Rollinschaeta myoplena (Annelida: Amphinomidae)", "abstract": "The process of soft\u2010tissue phosphatization (the replication of labile tissues by calcium phosphate) is responsible for many instances of high\u2010resolution soft tissue preservation, often revealing anatomical insights into the animals that so preserved. However, while much work has gone into exploring key issues such as biases and micro\u2010controls, phosphatization remains poorly understood as a taphonomic process. Here, using camera lucida, plain\u2010light microscopy and SEM imagery, we address this issue by describing the taphonomy and fidelity of the musculature of Rollinschaeta myoplena Parry et al., a phosphatized annelid from the Cretaceous Konservat\u2010Lagerst\u00e4tten of Hakel and Hjoula, Lebanon, with an unprecedented quantity of three\u2010dimensional soft\u2010tissue preservation. Analysis highlights two strong, previously recognized biases affecting the process of phosphatization: (1) a taxonomic bias restricted to R. myoplena that triggers unusually extensive phosphatization; and (2) a tissue bias whereby longitudinal and parapodial musculature show markedly higher fidelity in comparison to the musculature of the intestine and body wall circular muscles. Potential explanations for these biases include internal phosphate\u2010enrichment by relative muscle density, the relative rate of decay and the physiology of musculature. Incongruence between experimental decay series for polychaetes and the prevalence of labile tissue preservation over recalcitrant tissues in R. myoplena exposes the limits of decay experiments for understanding exceptional preservation.", "keyphrases": ["soft\u2010tissue phosphatization", "musculature", "tissue"]}
{"id": "paleo.012329", "title": "High frequencies of theropod bite marks provide evidence for feeding, scavenging, and possible cannibalism in a stressed Late Jurassic ecosystem", "abstract": "Bite marks provide direct evidence for trophic interactions and competition in the fossil record. However, variations in paleoecological dynamics, such as trophic relationships, feeding behavior, and food availability, govern the frequency of these traces. Theropod bite marks are particularly rare, suggesting that members of this clade might not often focus on bone as a resource, instead preferentially targeting softer tissues. Here, we present an unusually large sample of theropod bite marks from the Upper Jurassic Mygatt-Moore Quarry (MMQ). We surveyed 2,368 vertebrate fossils from MMQ in this analysis, with 684 specimens (28.885% of the sample) preserving at least one theropod bite mark. This is substantially higher than in other dinosaur-dominated assemblages, including contemporaneous localities from the Morrison Formation. Observed bite marks include punctures, scores, furrows, pits, and striations. Striated marks are particularly useful, diagnostic traces generated by the denticles of ziphodont teeth, because the spacing of these features can be used to provide minimum estimates of trace maker size. In the MMQ assemblage, most of the striations are consistent with denticles of the two largest predators known from the site: Allosaurus and Ceratosaurus. One of the bite marks suggests that a substantially larger theropod was possibly present at the site and are consistent with large theropods known from other Morrison Formation assemblages (either an unusually large Allosaurus or a separate, large-bodied taxon such as Saurophaganax or Torvosaurus). The distribution of the bite marks on skeletal elements, particularly those found on other theropods, suggest that they potentially preserve evidence of scavenging, rather than active predation. Given the relative abundances of the MMQ carnivores, partnered with the size-estimates based on the striated bite marks, the feeding trace assemblage likely preserves the first evidence of cannibalism in Allosaurus.", "keyphrases": ["frequency", "theropod bite mark", "cannibalism", "morrison formation"]}
{"id": "10.26879/1062", "title": "Geometric morphometric assessment of Guanshan trilobites (Yunnan Province, China) reveals a limited diversity of palaeolenid taxa", "abstract": "The Guanshan Biota is a typical Burgess Shale-type Cambrian-aged Lagerst\u00e4tte with diverse trilobites. As such, the taxonomy of trilobites from the Guanshan Biota, especially the palaeolenid group, has been the focus of research over the last decade. To develop this research, we present a geometric morphometric analysis of cranidial shape in 60 specimens from three sections of the Guanshan Biota from the Wulongqing Formation (Cambrian Series 2, Stage 4), Yunnan Province, South China. We show that cranidia of Megapalaeolenus deprati and Palaeolenus douvillei occupy distinct regions of morphospaces and that P. douvillei and P. \u201clantenoisi\u201d occupy the same region of morphospace. Combined with qualitative observation on the thorax, P. \u201clantenoisi\u201d is here considered a junior synonym of P. douvillei. Megapalaeolenus deprati is still considered valid and is distinguished from P. douvillei by its rounded glabella, longer palpebral lobes, shorter ocular ridges, and more developed posterolateral projections. Its pleural spines are more curved, and pleural lobes are markedly wider than P. douvillei. These results highlight that the supposed diversity of palaeolenid taxa in lower Cambrian deposits need reconsideration, potentially using similar morphometric methods. Wenyu Zhao. Early Life Institute, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi\u2019an, Shaanxi, China. zhaowenyunwu@126.com Jianni Liu. Early Life Institute, State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi\u2019an, Shaanxi, China. liujianni@126.com Russell D.C. Bicknell. Palaeoscience Research Centre, School of Environmental and Rural Science, University of New England, Armidale, New South Wales, Australia, 2351. rdcbicknell@gmail.com", "keyphrases": ["trilobite", "yunnan province", "china", "palaeolenid taxa"]}
{"id": "paleo.002887", "title": "Coccolithophore calcification response to past ocean acidification and climate change", "abstract": "Anthropogenic carbon dioxide emissions are forcing rapid ocean chemistry changes and causing ocean acidification (OA), which is of particular significance for calcifying organisms, including planktonic coccolithophores. Detailed analysis of coccolithophore skeletons enables comparison of calcite production in modern and fossil cells in order to investigate biomineralization response of ancient coccolithophores to climate change. Here we show that the two dominant coccolithophore taxa across the Paleocene\u2013Eocene Thermal Maximum (PETM) OA global warming event (~56 million years ago) exhibited morphological response to environmental change and both showed reduced calcification rates. However, only Coccolithus pelagicus exhibits a transient thinning of coccoliths, immediately before the PETM, that may have been OA-induced. Changing coccolith thickness may affect calcite production more significantly in the dominant modern species Emiliania huxleyi, but, overall, these PETM records indicate that the environmental factors that govern taxonomic composition and growth rate will most strongly influence coccolithophore calcification response to anthropogenic change.", "keyphrases": ["calcification response", "ocean acidification", "climate change", "coccolithus pelagicus"]}
{"id": "paleo.003478", "title": "Understanding Eocene primate palaeobiology using a comprehensive analysis of living primate ecology, biology and behaviour", "abstract": "The comparative method is central to interpretations of Eocene primate palaeobiology. This method rests upon a thorough study of analogous living forms. With a rapidly increasing knowledge of such forms, most notably the Malagasy lemurs, our ability to advance the study of Eocene primate ecology, biology and behaviour far exceeds that of even just a few years ago. Here we present such a comparison. Based on our data collected from both living lemurs and extant lemur skeletal specimens, we are able to make a number of comparisons that provide insight into middle Eocene primate ecology and palaeobiology. At the Beza Mahafaly Special Reserve, Madagascar, omnivorous living ring-tailed lemurs that feed on large, hard and tough fruits display a pattern of frequent post-canine tooth wear laterality (62 %) when compared to sympatric, folivorous Verreaux's sifaka (4 %). Our results indicate that Notharctus does not display a high frequency of tooth wear laterality (7 %), indicating folivory without processing large, hard fruits with its postcanines. Our data on Notharctus tooth wear also indicate, similar to living ring-tailed lemurs at Beza Mahafaly, that numerous individuals (21 %) survived long enough to experience heavy tooth wear, contrary to the assumption that heavy tooth wear leads to the rapid death of the individual. Finally, our data on trauma and injury from a living lemur population suggest that the reported wrist injury in Darwinius masillae (i.e. \"Ida\") did not necessarily lead to her death, as numerous ring-tailed lemurs at Beza Mahafaly survive with similar or even more traumatic injuries and maintain the ability to climb. Thus, our data from living primates provide a broad comparative framework for interpreting the ecology, biology and behaviour of Eocene forms.", "keyphrases": ["eocene primate palaeobiology", "behaviour", "lemur population"]}
{"id": "10.1073/pnas.2022466118", "title": "Reevaluating the timing of Neanderthal disappearance in Northwest Europe", "abstract": "Significance Understanding when Neanderthals disappeared is a hotly debated topic. When radiocarbon dating placed the Spy Neanderthals amongst the latest surviving in Northwest Europe, questions were raised regarding the reliability of the dates. Using a procedure more efficient in removing contamination and ancient genomic analysis, we show that previous dates produced on Neanderthal specimens from Spy are too young by up to 10,000 y. Our direct radiocarbon dates on the Neanderthals from Spy and those from Engis and Fonds-de-For\u00eat show a reduction of the uncertainty for the time window corresponding to Neanderthal disappearance in Northwest Europe. This population disappeared at 44,200 to 40,600 cal B.P. (at 95.4% probability). This is also earlier than previous suggestions based on dates on bulk collagen. Elucidating when Neanderthal populations disappeared from Eurasia is a key question in paleoanthropology, and Belgium is one of the key regions for studying the Middle to Upper Paleolithic transition. Previous radiocarbon dating placed the Spy Neanderthals among the latest surviving Neanderthals in Northwest Europe with reported dates as young as 23,880 \u00b1 240 B.P. (OxA-8912). Questions were raised, however, regarding the reliability of these dates. Soil contamination and carbon-based conservation products are known to cause problems during the radiocarbon dating of bulk collagen samples. Employing a compound-specific approach that is today the most efficient in removing contamination and ancient genomic analysis, we demonstrate here that previous dates produced on Neanderthal specimens from Spy were inaccurately young by up to 10,000 y due to the presence of unremoved contamination. Our compound-specific radiocarbon dates on the Neanderthals from Spy and those from Engis and Fonds-de-For\u00eat demonstrate that they disappeared from Northwest Europe at 44,200 to 40,600 cal B.P. (at 95.4% probability), much earlier than previously suggested. Our data contribute significantly to refining models for Neanderthal disappearance in Europe and, more broadly, show that chronometric models regarding the appearance or disappearance of animal or hominin groups should be based only on radiocarbon dates obtained using robust pretreatment methods.", "keyphrases": ["neanderthal disappearance", "northwest europe", "procedure"]}
{"id": "paleo.002499", "title": "Homology problems in cephalopod morphology: deceptive (dis)similarities between different types of 'caecum'", "abstract": "Homoplasy is a common phenomenon in the evolution of the Cephalopoda. Many homology problems accordingly light up phylogenetic debates. The initial segment of the siphuncle, the so-called 'caecum', is one of these characters difficult to be unambiguously evaluated. Although rarely discussed, the caecum of the endocochleate decabrachian Spirula is traditionally seen as a plesiomorphy directly inherited from its ectocochleate ancestors. However, the Spirula caecum must be-according to recent phylogenetic analyses-derived from a substructure of the belemnoid protoconch. Here, I review the morphology of different types of ectocochleate and endocochleate protoconchs. Detailed comparisons show that belemnoid protoconchs are structurally closer to the bactritoid/ammonoid protoconch than to the spiruloid protoconch. The most striking difference between the caecum of Spirula and bactritoids or ammonoids concerns its ultrastructure, which is lamello-fibrillar nacre (Spirula nacre or nacre type II) in the former and organic in the latter. The Spirula caecum is consequently equivalent to the first septum, while in bactritoids/ammonoids, the caecum is a separate structure independent of the proseptum. To conclude, the spiruloid protoconch (including caecum) has been derived either from a belemnitid or diplobelid protoconch. Similarities between the bactritoid/ammonoid and spiruloid caecum are superficial and only concern its shape.", "keyphrases": ["morphology", "caecum", "initial segment", "homology problem"]}
{"id": "10.1029/2003GB002140", "title": "Biological fractionation of silicon isotopes in Southern Ocean surface waters", "abstract": "The fractionation of silicon isotopes by diatoms during silicification (i.e., opaline cell wall formation) provides a new tool for paleoceanographic studies of the silicon cycle. Here we examine the natural variations of the 30Si:28Si ratio in silicic acid (Si(OH)4) and biogenic silica (bSiO2) in surface waters of the Antarctic Circumpolar Current (ACC) along 170\u00b0W. The results provide direct evidence of biologically mediated fractionation of silicon isotopes, with an enrichment factor (\u025b) of between \u22121.1 and \u22121.9\u2030, depending on the model employed. Comparison of the mass flux of bSiO2 captured in sediment traps deployed in the study area with the silicon isotopic composition of that material establishes a direct linkage between diatom dynamics in surface waters and the isotopic signature of exported particles. We calculated Si(OH)4:NO3\u2212 utilization ratios from variations in silicon and nitrogen isotopic ratios in surface waters and sediment traps that agree well with direct observations of 4:1 in this region. This work supports the use of variations in silicon isotopes in sedimentary opal as a proxy for relative Si(OH)4 utilization in surface waters.", "keyphrases": ["fractionation", "silicon isotope", "surface water"]}
{"id": "10.1080/02724634.2016.1095201", "title": "A Skull of Plesiaceratherium gracile (Rhinocerotidae, Perissodactyla) from a New Lower Miocene Locality in Shandong Province, China, and the Phylogenetic Position of Plesiaceratherium", "abstract": "ABSTRACT \n A well-preserved fossil skull from a new locality in Jijiazhuang, Changle County, Shandong Province, China, is attributable to Plesiaceratherium gracile. Other rhinoceroses from the nearby Shanwang Basin of Linqu County, Shandong, formerly described as Aceratherium sp. and Plesiaceratherium shanwangensis are also referable to P. gracile. The new skull demonstrates the presence in P. gracile of the following characters: continuous labial cingula on lower cheek teeth; skull roof with nearly flat profile; and external auditory pseudomeatus ventrally closed, proceeding dorsocaudally in a shallow groove. Comparison of Plesiaceratherium with Brachypotherium pugnator Matsumoto, 1921, suggests that referral of the latter to Plesiaceratherium should be reconsidered. A phylogenetic analysis based on 314 characters scored for 39 terminal taxa places Plesiaceratherium mirallesi in a basal position within Rhinocerotidae, and recovers other species of Plesiaceratherium as a clade that is well separated from B. pugnator and is sister to the [Subchilotherium [Acerorhinus [Shansirhinus, B. pugnator [Chilotherium]]]] grouping. Based on this result and a reevaluation of the anatomy of \u2018P.\u2019 mirallesi, we propose that the genus Dromoceratherium should be revived to accommodate this species as D. mirallesi. The occurrence of P. gracile at Jijiazhuang indicates that the fossiliferous diatomaceous shales of this locality were deposited during the lower Miocene.", "keyphrases": ["skull", "plesiaceratherium gracile", "rhinocerotidae"]}
{"id": "10.1671/039.029.0216", "title": "First Record and a New Species of Seriema (Aves: Ralliformes: Cariamidae) from Santacrucian (Early-Middle Miocene) Beds of Patagonia", "abstract": "Living seriemas (Ralliformes, Cariamidae) are long-legged cursorial birds that comprise only two very closely related, and perhaps congeneric, species (Gonzaga, 1996): Cariama cristata and Chunga burmeisteri. They are endemic to South America and may represent surviving Neotropical relicts of an early ralli form radiation within the suborder Cariamae. Phorusrhacids, idiornithids, and bathornithids are also extinct components of ralliforms, a large terrestrial stock of predator or scavenger birds, which were abundant during the Tertiary of South and North America, and Europe (Mourer Chauvire, 1981, 1983; Alvarenga and H?fling, 2003). The phylogenetic relation ships and paleobiogeographic history of phorusrhacids, idior nithids, and bathornithids are still far from being resolved. Tertiary fossils of the cariamid subtaxon Cariaminae are scarce and restricted to the questionable record of Riacama caliginea Ameghino 1899 from the late Oligocene (Deseadan age) of Santa Cruz Province (see Brodkorb, 1967; Tonni, 1980; Tambussi and Noriega, 1996; Agnolin, 2004), and the early-middle Pliocene (Montehermosan age) record of Chunga incerta Tonni (1974) from Buenos Aires Province, both in Argentina. In this contribution we present new remains of seriemas re covered in 2005 by a joint expedition of the Museo de La Plata, Argentina, and Duke University, USA. They come from the middle levels of the Santa Cruz Formation (Upper-middle Mio cene) along the Atlantic coast of southernmost continental Pata gonia, Argentina, between the Coyle and Gallegos rivers. These localities are situated at about 52 degrees South latitude, about 100 km north to the Magallanes Strait (Fig. 1). In the mentioned area, the Santa Cruz Formation bears a terrestrial vertebrate fauna exceptional in its richness with over 70 species recorded in about 30 fossiliferous levels (Tauber, 1997a, Tauber 1997b; Tauber et al., 2004) that represents the richest assemblage of pre-Pleistocene mammalian skulls and ar ticulated skeletons known in the continent (Hatcher, 1903). A description of the localities and horizons that produced the fossils reported here is provided in the following section. Although still far fewer than mammals, these localities have provided quite a number of bird remains. Many of them were described and beautifully figured in the extensive Reports of the Princeton University Expeditions to Patagonia (Sinclair and Farr, 1932). They include Phorusrhacos longissimus Ameghino 1887, Brontornis burmeisteri Moreno and Mercerat 1891, Patagornis marshi Moreno and Mercerat 1891, Psilopterus bachmanni (Moreno and Mercerat 1891), and Psilopterus lemoinei (Moreno and Mercerat 1891), among the Phorusrhacids. Other bird taxa recorded at the Santa Cruz Formation include Tinamidae (Chiappe, 1991), Rheidae (Opisthodactylus patagonicus Ame ghino 1891), Pelecanidae (Liptornis hesternus Ameghino 1895), Plataleidae (Protibis cnemialis Ameghino 1891), Anatidae (Eone ornis australis Ameghino 1895; Eutelornis patagonicus Ameghino 1895), Aramidae (Anisolornis excavatus Ameghino 1891), and Falconiformes (Badiostes patagonicus Ameghino 1895; Thegornis debilis Ameghino 1895 and T. musculosus Ameghino 1899). Most of these taxa were erected on the basis of very fragmentary and eroded specimens, together with brief and poorly illustrated descriptions, that make difficult to assess their validity (Olson, 1981, 1985; Tonni, 1980; Tambussi and Noriega, 1996). Some of them have been recently revised (Alvarenga and H?fling, 2003; Agnolin, 2004, 2006, 2007).", "keyphrases": ["ralliformes", "cariamidae", "patagonia"]}
{"id": "10.1002/2014PA002702", "title": "I/Ca evidence for upper ocean deoxygenation during the PETM", "abstract": "Anthropogenic global warming affects marine ecosystems in complex ways, and declining ocean oxygenation is a growing concern. Forecasting the geographical and bathymetric extent, rate, and intensity of future deoxygenation and its effects on oceanic biota, however, remains highly challenging because of the complex feedbacks in the Earth-ocean biota system. Information on past global warming events such as the Paleocene-Eocene Thermal Maximum (PETM, ~55.5\u2009Ma), a potential analog for present and future global warming, may help in such forecasting. Documenting past ocean deoxygenation, however, is hampered by the lack of sensitive proxies for past oceanic oxygen levels throughout the water column. As yet no evidence has been presented for pervasive deoxygenation in the upper water column through expansion of oxygen minimum zones (OMZs). We apply a novel proxy for paleoredox conditions, the iodine to calcium ratio (I/Ca) in bulk coarse fraction sediment and planktonic foraminiferal tests from pelagic sites in different oceans, and compared our reconstruction with modeled oxygen levels. The reconstructed iodate gradients indicate that deoxygenation occurred in the upper water column in the Atlantic, Indian Oceans, and possibly the Pacific Ocean, as well during the PETM, due to vertical and potentially lateral expansion of OMZs.", "keyphrases": ["ocean deoxygenation", "petm", "oxygen minimum zone"]}
{"id": "paleo.010552", "title": "The Origin and Early Evolution of Sauria: Reassessing the Permian Saurian Fossil Record and the Timing of the Crocodile-Lizard Divergence", "abstract": "Sauria is the crown-group of Diapsida and is subdivided into Lepidosauromorpha and Archosauromorpha, comprising a high percentage of the diversity of living and fossil tetrapods. The split between lepidosauromorphs and archosauromorphs (the crocodile-lizard, or bird-lizard, divergence) is considered one of the key calibration points for molecular analyses of tetrapod phylogeny. Saurians have a very rich Mesozoic and Cenozoic fossil record, but their late Paleozoic (Permian) record is problematic. Several Permian specimens have been referred to Sauria, but the phylogenetic affinity of some of these records remains questionable. We reexamine and review all of these specimens here, providing new data on early saurian evolution including osteohistology, and present a new morphological phylogenetic dataset. We support previous studies that find that no valid Permian record for Lepidosauromorpha, and we also reject some of the previous referrals of Permian specimens to Archosauromorpha. The most informative Permian archosauromorph is Protorosaurus speneri from the middle Late Permian of Western Europe. A historically problematic specimen from the Late Permian of Tanzania is redescribed and reidentified as a new genus and species of basal archosauromorph: Aenigmastropheus parringtoni. The supposed protorosaur Eorasaurus olsoni from the Late Permian of Russia is recovered among Archosauriformes and may be the oldest known member of the group but the phylogenetic support for this position is low. The assignment of Archosaurus rossicus from the latest Permian of Russia to the archosauromorph clade Proterosuchidae is supported. Our revision suggests a minimum fossil calibration date for the crocodile-lizard split of 254.7 Ma. The occurrences of basal archosauromorphs in the northern (30\u00b0N) and southern (55\u00b0S) parts of Pangea imply a wider paleobiogeographic distribution for the group during the Late Permian than previously appreciated. Early archosauromorph growth strategies appear to be more diverse than previously suggested based on new data on the osteohistology of Aenigmastropheus.", "keyphrases": ["sauria", "divergence", "archosauromorph", "paleozoic"]}
{"id": "10.1111/j.1502-3931.1988.tb01745.x", "title": "Dasyclads, cyclocrinitids and receptaculitids: comparative morphology and paleoecology", "abstract": "The cyclocrinitids are an extinct tribe of dasycladacean green algae. They were anatomically very similar to certain Recent dasyclads, even at early growth stages. The morphology and preservation of cyclocrinitids strongly suggest that they had a siphonous cellular organization with extracellular, aragonitic calcification; these features are characteristic of living dasyclads. The light surficial calcification of cyclocrinitids and other dasyclads had important paleoecological effects. It restricted them to low-energy waters, as it provided relatively little structural support. It also confined them to warm, tropical waters; they are good paleoequatorial indicators. The decline of these algae during the late Ordovician and early Silurian may therefore reflect the simultaneous cooling and glaciation. Receptaculitids are entirely unrelated organisms. Their meroms have several distinctive features; they are not homologous to the lateral branches of cyclocrinitids or dasyclads. Receptaculitid calcification was extensive and their thalli were apparently quite sturdy; they often occurred in reefs. Receptaculitids also lived in high-latitude, cold-water environments. Thus, they were ecologically unlike any calcareous green algae, and cannot be used as paleoequatorial indicators. Receptaculitids remain problematical, although the arrangement of meroms suggests plant affinities. \u25a1Calcareous algae, Problematica, Dasycladales, Cyclocriniteae, Receptaculitales, morphology, classification, paleoecology, paleogeography.", "keyphrases": ["receptaculitid", "paleoecology", "algae", "dasyclad"]}
{"id": "10.1111/j.1365-3121.1991.tb00200.x", "title": "Bustylus (Eutheria, Adapisoriculidae) and the absence of ascertained marsupials in the Palaeocene of Europe", "abstract": "The recent description of the new adapisoriculid placental Bustylus cernaysi from the Thanetian of Cernay, and possibly of Walbeck, permits a new assessment of the systematic position of the supposed marsupial \u2018Peradectes\u2019 marandati from the Montian of Hainin (Belgium). The affinity between the two species is demonstrated and the species \u2018P.\u2019 marandati is included in the genus Bustylus (family Adapisoriculidae) and is excluded from the direct ancestry of B. cernaysi only because of the apparent absence of the D cusp in the known sample. Comparison with the oldest known placental, Prokennalestes (otlestid), supports the eutherian nature of Bustylus marandati and B. cernaysi. It also shows that the adapisoriculids are morphologically closer to the primitive otlestids than to the paleoryctids, which are more specialized in several respects. One general conclusion is the absence of known marsupials in the Palaeocene of Europe, their occurrence in this continent being ascertained only from the beginning of the Eocene (i.e. early Sparnacian or MP 7 reference level).", "keyphrases": ["marsupial", "palaeocene", "europe", "genus bustylus"]}
{"id": "paleo.006653", "title": "A giant nektobenthic radiodont from the Burgess Shale and the significance of hurdiid carapace diversity", "abstract": "Radiodonts, stem-group euarthropods that evolved during the Cambrian explosion, were among the largest and most diversified lower palaeozoic predators. These animals were widespread geographically, occupying a variety of ecological niches, from benthic foragers to nektonic suspension feeders and apex predators. Here, we describe the largest Cambrian hurdiid radiodont known so far, Titanokorys gainesi, gen. et sp. nov., from the Burgess Shale (Marble Canyon, Kootenay National Park, British Columbia). Estimated to reach half a metre in length, this new species bears a very large ovoid-shaped central carapace with distinct short posterolateral processes and an anterior spine. Geometric morphometric analyses highlight the high diversity of carapace shapes in hurdiids and show that Titanokorys bridges a morphological gap between forms with long and short carapaces. Carapace shape, however, is prone to homoplasy and shows no consistent relationship with trophic ecology, as demonstrated by new data, including a reappraisal of the poorly known Pahvantia. Despite distinct carapaces, Titanokorys shares similar rake-like appendages for sediment-sifting with Cambroraster, a smaller but much more abundant sympatric hurdiid from the Burgess Shale. The co-occurrence of these two species on the same bedding planes highlights potential competition for benthic resources and the high diversity of large predators sustained by Cambrian communities.", "keyphrases": ["radiodont", "burgess shale", "carapace shape"]}
{"id": "10.1017/S0094837300010198", "title": "A functional interpretation of the masticatory system and paleoecology of entelodonts", "abstract": "Entelodonts are medium to large (perhaps 150\u2013750 kg) Oligocene\u2013Miocene bunodont artiodactyls with unique crania but typical artiodactyl postcrania. Functional and ecological interpretations are difficult because there is no clear modern analog to an entelodont in size, dentition, and cranial morphology. Entelodont crania combine primitive and derived features, including laterally expanded zygomatic arch/large temporal fossa (suggesting a large temporalis muscle), unreduced dental formula, long premolar row, fused mandibular symphysis, isognathy, and subcylindrical dentary condyles. Furthermore, the cranium has unique architectural and ontogenetic aspects unparalleled in extant mammals. Canines show heavy, carnivoran-like, apical wear in old individuals, suggesting regular contact with food. Conical premolars and associated diastemata dominate the tooth row. Premolars are often apically worn, in a fashion somewhat like those of carnivorans (e.g., Crocuta, Borophagus). Molars are low-cusped crushing teeth. Wide gape, indicated by the form of the coronoid process and temporal fossa, facilitated canine and premolar use, probably both in feeding and in social behavior. Jaw mechanics, tooth morphology, and tooth wear are compatible with omnivory and probable scavenging, an intriguing proposition for the huge Dinohyus hollandi.", "keyphrases": ["entelodont", "dentition", "cranial morphology", "canine", "wide gape"]}
{"id": "10.1144/GSL.SP.2003.217.01.16", "title": "Pterosaur tracks from the latest Campanian Cerro del Pueblo Formation of southeastern Coahuila, Mexico", "abstract": "Abstract A new vertebrate tracksite in southeastern Coahuila, northern M\u00e9xico, known as the El Pelillal tracksite (Latest Campanian, Cerro del Pueblo Formation) has yielded an important ichnofauna that includes the tracks of turtles, crocodilians, a small theropod dinosaur, a mammal-like organism and the tracks of pterosaurs. The pterosaurian manus impressions share an extraordinary similarity, in size and morphology, with the Jurassic ichnogenus Pteraichnus Stokes 1957 and are referred to Pteraichnus sp.; however, the pes impressions differ in that they are rather very elongated. According to the geological features and ichnofauna the El Pelillal tracksite represents a shallow, freshwater or lacustrine deposit, which agrees with our knowledge about the habitat preference of Cretaceous pterosaurs. This newly discovered tracksite in southeastern Coahuila, Mexico, offers great potential for palaeoichnological research and is thus becoming important in the understanding of the palaeoecosystems during the Late Cretaceous in southern North America.", "keyphrases": ["track", "southeastern coahuila", "mexico"]}
{"id": "10.1111/jse.12534", "title": "Northern Hemisphere megafossil of Dacrycarpus (Podocarpaceae) from the Miocene of South China and its evolutionary and paleoecological implications", "abstract": "The modern genus Dacrycarpus (Endl.) de Laub. of the family Podocarpaceae, containing nine species, is mainly distributed in tropical mountain rainforests of the southwestern Pacific region, ranging from New Zealand to low\u2010latitude Asia. This genus has abundant fossil records in both hemispheres, but all the known megafossils were limited to Australasia and South America. Here we report on Dacrycarpus guipingensis sp. nov. from the Miocene Erzitang Formation of Guangxi, South China. This is the first megafossil of Dacrycarpus in the Northern Hemisphere. The new species is represented by mummified dimorphic foliage, ovuliferous shoots, and a male cone with in situ pollen. It resembles the extant Dacrycarpus imbricatus (Blume) de Laub., which is common in rainforests from southern China and northern Myanmar to Fiji. This paper presents the first data on the anatomical structure of seed cone and exine ultrastructure of Dacrycarpus in situ pollen grains from a fossil material by using computed tomography scanning and ultrathin sectioning. For comparative purpose, data on the pollen morphology and ultrastructure were obtained for modern D. imbricatus for the first time. The D. guipingensis fossils strongly suggest the Miocene arrival of Dacrycarpus in Asia from the Southern Hemisphere. Based on the modern ecological niche and related fossil elements, this fossil locality was probably covered by conifer\u2013broad\u2010leaved mountain rainforests during the Miocene.", "keyphrases": ["dacrycarpus", "miocene", "rainforest"]}
{"id": "10.1029/2007PA001531", "title": "A modeling assessment of the interplay between aeolian iron fluxes and iron-binding ligands in controlling carbon dioxide fluctuations during Antarctic warm events", "abstract": "[1]\u00a0We add a prognostic biogeochemical model to the Bern3D ocean circulation model to test the impact of increased aeolian iron fluxes in various regions of the ocean on long time scales. Atmospheric CO2 is most sensitive when modern dust flux is increased 100-fold in the Southern Ocean for 1000 years, resulting in a reduction of 10 ppmv. Seeding the Indian Ocean and South Pacific results in increased export production and CO2 drawdown in the Southern Ocean due to interbasinal transport of iron. The non-sea-salt calcium record from Dome C, Antarctica, is used to scale aeolian iron deposition in the Southern Ocean in transient simulations over four Antarctic warm events of the last glacial period. Our results suggest changes in dust flux to the Southern Ocean played a limited role in modulating CO2 variations. The impact of iron fluxes on CO2 is dependent on parameter values chosen for the iron-binding ligand.", "keyphrases": ["aeolian iron flux", "iron-binding ligand", "antarctic warm event", "ocean"]}
{"id": "10.2110/palo.2009.p09-129r", "title": "LEAF MARGIN ANALYSIS: A NEW EQUATION FROM HUMID TO MESIC FORESTS IN CHINA", "abstract": "Abstract Leaf margin analysis (LMA) is a widely used method that applies present-day linear correlation between the proportion of woody dicotyledonous species with untoothed leaves (P) and mean annual temperature (MAT) to estimate paleotemperatures from fossil leaf floras. Previous works demonstrate that LMA shows regional constraints and to date, no equation has been modeled directly from Chinese forests. Fifty humid to mesic Chinese forests were chosen to understand the relationship between percentage of untoothed leaf species and MAT in China. Consistent with previous studies, the Chinese data indicate that P shows a strong linear correlation with MAT, but the actual relationship is a little different from those recognized from other regions. Among the several currently used LMA equations, the one resulting from North and Central American and Japanese data, rather than the widely used East Asian LMA equation, yields the closest values to the actual MATs of the Chinese samples (mean absolute error = 1.9 \u00b0C). A new equation derived from the Chinese forests is therefore developed, where MAT = 1.038 + 27.6 \u00d7 P. This study not only demonstrates the similarity of the relationship between P and MAT in the Northern Hemisphere, but also improves the reliability of LMA for paleoclimate reconstructions of Chinese paleofloras.", "keyphrases": ["new equation", "china", "lma", "annual temperature", "leaf margin analysis"]}
{"id": "paleo.009844", "title": "Anatomy and Taxonomic Status of the Chasmosaurine Ceratopsid Nedoceratops hatcheri from the Upper Cretaceous Lance Formation of Wyoming, U.S.A", "abstract": "Background The validity of Nedoceratops hatcheri, a chasmosaurine ceratopsid dinosaur known from a single skull recovered in the Lance Formation of eastern Wyoming, U.S.A., has been debated for over a century. Some have argued that the taxon is an aberrant Triceratops, and most recently it was proposed that N. hatcheri represents an intermediate ontogenetic stage between \u201cyoung adult\u201d and \u201cold adult\u201d forms of a single taxon previously split into Triceratops and Torosaurus. Methodology/Principal Findings The holotype skull of Nedoceratops hatcheri was reexamined in order to map reconstructed areas and compare the specimen with other ceratopsids. Although squamosal fenestrae are almost certainly not of taxonomic significance, some other features are unique to N. hatcheri. These include a nasal lacking a recognizable horn, nearly vertical postorbital horncores, and relatively small parietal fenestrae. Thus, N. hatcheri is tentatively considered valid, and closely related to Triceratops spp. The holotype of N. hatcheri probably represents an \u201cold adult,\u201d based upon bone surface texture and the shape of the horns and epiossifications on the frill. In this study, Torosaurus is maintained as a genus distinct from Triceratops and Nedoceratops. Synonymy of the three genera as ontogenetic stages of a single taxon would require cranial changes otherwise unknown in ceratopsids, including additions of ossifications to the frill and repeated alternation of bone surface texture between juvenile and adult morphotypes. Conclusions/Significance Triceratops, Torosaurus, and likely Nedoceratops, are all distinct taxa, indicating that species richness for chasmosaurine ceratopsids in the Lance Formation just prior to the Cretaceous-Paleocene extinction was roughly equivalent to that earlier in the Cretaceous.", "keyphrases": ["nedoceratops hatcheri", "ontogenetic stage", "torosaurus"]}
{"id": "10.1073/pnas.1202629109", "title": "Border Cave and the beginning of the Later Stone Age in South Africa", "abstract": "The transition from the Middle Stone Age (MSA) to the Later Stone Age (LSA) in South Africa was not associated with the appearance of anatomically modern humans and the extinction of Neandertals, as in the Middle to Upper Paleolithic transition in Western Europe. It has therefore attracted less attention, yet it provides insights into patterns of technological evolution not associated with a new hominin. Data from Border Cave (KwaZulu-Natal) show a strong pattern of technological change at approximately 44\u201342 ka cal BP, marked by adoption of techniques and materials that were present but scarcely used in the previous MSA, and some novelties. The agent of change was neither a revolution nor the advent of a new species of human. Although most evident in personal ornaments and symbolic markings, the change from one way of living to another was not restricted to aesthetics. Our analysis shows that: (i) at Border Cave two assemblages, dated to 45\u201349 and >49 ka, show a gradual abandonment of the technology and tool types of the post-Howiesons Poort period and can be considered transitional industries; (ii) the 44\u201342 ka cal BP assemblages are based on an expedient technology dominated by bipolar knapping, with microliths hafted with pitch from Podocarpus bark, worked suid tusks, ostrich eggshell beads, bone arrowheads, engraved bones, bored stones, and digging sticks; (iii) these assemblages mark the beginning of the LSA in South Africa; (iv) the LSA emerged by internal evolution; and (v) the process of change began sometime after 56 ka.", "keyphrases": ["later stone age", "south africa", "border cave"]}
{"id": "paleo.004074", "title": "A taxonomic revision of orthosternous scorpions from the English Coal Measures aided by x-ray micro-tomography (XMT)", "abstract": "Fossil scorpion systematics -particularly that of the diverse assemblage found in Carboniferous Coal Measure deposits -are problematic, being characterised by a large number of frequently monotypic taxa, based on a limited set of characters. These Palaeozoic scorpions have the potential to elucidate the nature of the scorpion stemgroup and hence to inform long running debates regarding the origin of the crown group and relationships between extant lineages. Carboniferous taxa are often found in siderite concretions and can be preserved in three dimensions. This study investigates two such fossils of the species Compsoscorpius buthiformis (Pocock, 1911) with the aid of X-ray Micro-Tomography (XMT) and computer reconstruction. These scans reveal important new details of the anatomy, such as the walking legs, that allow more detailed comparison with coeval taxa. Many of these taxa are revealed here to be junior synonyms of C. buthiformis and previous taxonomic practice, as it relates to Coal Measures scorpions, is criticised. The ecology of C. buthiformis is also reviewed in light of the new evidence from XMT. In particular, aspects of its walking leg and metastomal anatomy are analogous to that of extant lithophilic and 'errant' leaf-litter scorpions.", "keyphrases": ["scorpion", "x-ray micro-tomography", "xmt", "synonym"]}
{"id": "10.1029/2010pa001976", "title": "Meridional shifts in the marine ITCZ and the tropical hydrologic cycle over the last three glacial cycles", "abstract": "[1]\u00a0Paleoproxy studies show a strong correlation between tropical climate and high-latitude temperature variability recorded in the Greenland ice cores over the last glacial cycle. In particular, abrupt cooling events in the Greenland Ice Sheet Project II \u03b418O ice record appear synchronous with a southward migration of the Intertropical Convergence Zone (ITCZ) in the Atlantic, a weakening of the Indian and East Asian monsoon systems, and a strengthening of the South American monsoon system. Because this high-to-low-latitude climate teleconnection significantly alters the tropical hydrologic cycle around the globe, it plays a critical role in regulating global climate on glacial-interglacial time scales. We compare \u03b418Oseawater reconstructions (a salinity proxy generated from previously published Mg/Ca and oxygen isotope data on Globigerinoides ruber (white var.)) obtained from western Caribbean core ODP 999A and western equatorial Pacific core 806B across the last three glacial cycles to show that systematic variations in surface salinity at these sites suggest the tropical Hadley cell hydrologic system undergoes systematic reorganizations that differ dramatically between warm interglacial and cold glacial periods. Furthermore, cross-spectral and phase angle analyses of the ice-volume-corrected Caribbean and western Pacific \u03b418OSW records reveal a 100 kyr frequency in both records that is almost 180\u00b0 out of phase and a 23 kyr frequency that is nearly in phase. This results in the development of a very large \u03b418OSW gradient between the Caribbean and the western equatorial Pacific on glacial-interglacial time scales that is best explained by a southward shift in both the Atlantic and Pacific ITCZ during North Atlantic cold phases.", "keyphrases": ["itcz", "tropical hydrologic cycle", "glacial cycle", "intertropical convergence zone"]}
{"id": "10.11646/palaeoentomology.2.1.5", "title": "Burmese (Myanmar) amber checklist and bibliography 2018", "abstract": "A list of all known taxa described or recorded from Burmese amber from the published literature up to the end of 2018 is given, along with a comprehensive bibliography. The history of the study of inclusions is summarised, and demonstrates that the number of species has risen exponentially over the past two decades. The first three species were named in 1916 and by the end of 1920 a total of 42 species had been named by T.D.A. Cockerell. Only three more species were named by 1999 though by the end of 2018 the total had risen to an incredible 1,192 species, of which over half were named in the past three years. Some 320 species were named in 2018, the highest number described from one type of amber in any one year in the entire history of amber studies.", "keyphrases": ["myanmar", "bibliography", "burmese amber", "arthropod"]}
{"id": "10.3389/fevo.2022.958032", "title": "Carbon, nitrogen, and oxygen stable isotopes in modern tooth enamel: A case study from Gorongosa National Park, central Mozambique", "abstract": "The analyses of the stable isotope ratios of carbon (\u03b413C), nitrogen (\u03b415N), and oxygen (\u03b418O) in animal tissues are powerful tools for reconstructing the feeding behavior of individual animals and characterizing trophic interactions in food webs. Of these biomaterials, tooth enamel is the hardest, most mineralized vertebrate tissue and therefore least likely to be affected by chemical alteration (i.e., its isotopic composition can be preserved over millions of years), making it an important and widely available archive for biologists and paleontologists. Here, we present the first combined measurements of \u03b413C, \u03b415N, and \u03b418O in enamel from the teeth of modern fauna (herbivores, carnivores, and omnivores) from the well-studied ecosystem of Gorongosa National Park (GNP) in central Mozambique. We use two novel methods to produce high-precision stable isotope enamel data: (i) the \u201coxidation-denitrification method,\u201d which permits the measurement of mineral-bound organic nitrogen in tooth enamel (\u03b415Nenamel), which until now, has not been possible due to enamel\u2019s low organic content, and (ii) the \u201ccold trap method,\u201d which greatly reduces the sample size required for traditional measurements of inorganic \u03b413Cenamel and \u03b418Oenamel (from \u22650.5 to \u22640.1 mg), permitting analysis of small or valuable teeth and high-resolution serial sampling of enamel. The stable isotope results for GNP fauna reveal important ecological information about the trophic level, dietary niche, and resource consumption. \u03b415Nenamel values clearly differentiate trophic level (i.e., carnivore \u03b415Nenamel values are 4.0\u2030 higher, on average, than herbivores), \u03b413Cenamel values distinguish C3 and/or C4 biomass consumption, and \u03b418Oenamel values reflect local meteoric water (\u03b418Owater) in the park. Analysis of combined carbon, nitrogen, and oxygen stable isotope data permits geochemical separation of grazers, browsers, omnivores, and carnivores according to their isotopic niche, while mixed-feeding herbivores cannot be clearly distinguished from other dietary groups. These results confirm that combined C, N, and O isotope analyses of a single aliquot of tooth enamel can be used to reconstruct diet and trophic niches. Given its resistance to chemical alteration, the analysis of these three isotopes in tooth enamel has a high potential to open new avenues of research in (paleo)ecology and paleontology.", "keyphrases": ["tooth enamel", "mozambique", "herbivore", "carbon"]}
{"id": "paleo.007303", "title": "Phylogenetic position of the crocodylian Megadontosuchus arduini and tomistomine palaeobiogeography", "abstract": "A cladistic analysis of Megadontosuchus arduini from the middle Eocene of Monte Duello (NE Italy) confirms its tomistomine relationships, but the low number of scorable characters determines a low resolution within the tomistomine clade. However, Megadontosuchus is clearly distinct from the other Eocene European or North African tomistomines, in having a moderate elongated but robust rostrum, massive maxillary and dentary teeth and large supratemporal fenestrae. The rostrum and teeth characteristics could indicate that M. arduini had a degree of feeding specialization intermediate between Maroccosuchus zennaroi and the Eocene European tomistomines. A summary of tomistomine palaeobiogeography suggests that despite only one species with a rather restricted range survives at present, such a clade had a glorious past with a world wide distribution documented by a conspicuous fossil record that starts at least in the early Eocene. At present, a detailed knowledge of tomistomine palaeobiogeography is hindered by the lack of modern taxonomic revisions of some fossil remains and therefore by the poor understanding of phylogenetic relationships.", "keyphrases": ["megadontosuchus arduini", "tomistomine palaeobiogeography", "eocene"]}
{"id": "10.1144/gsjgs.153.6.0853", "title": "Glaciation and sea-level change for Ireland and the Irish Sea since Late Devensian/Midlandian time", "abstract": "The sea-level change around the coast of Ireland and the Irish Sea for the past 20 000 years is primarily the combined result of the glacio-isostatic adjustment of the crust to the removal of ice over the British Isles and the total eustatic change from the global ice sheets. However, the isostatic effects due to the removal of ice from northern Europe and North America and the addition of meltwater into the oceans also make a significant contribution. Predictions of sea-level change, based on glacio-hydro-isostatic models are compared with observations to constrain the ice volume over Ireland at the time of the last glacial maximum and the maximum ice height appears to have been of the order of 600 m. The models predict well the spatial variability in sea-level change observed across the region for Holocene and Lateglacial time, with levels above present being predicted only for northeastern Ireland and north of about Morecambe Bay. The models do not support suggestions that Lateglacial levels along the east coast of Ireland or the coast of Wales were 50\u2013150 m above their present levels. Consistent models that would produce such large Lateglacial highstands are incompatible with all other sea level and glacial evidence for the British Isles. Palaeobathymetry and palaeoshoreline reconstructions for the Irish Sea indicates that a tenuous landbridge between Britain and Ireland developed only across the Celtic Sea, between about 18000 and 14000 years bp.", "keyphrases": ["sea-level change", "irish sea", "ice sheet", "glacial maximum"]}
{"id": "10.1080/14772019.2012.686927", "title": "New proviverrine genus from the Early Eocene of Europe and the first phylogeny of Late Palaeocene\u2013Middle Eocene hyaenodontidans (Mammalia)", "abstract": "A new genus and new species of Proviverrinae from the Early Eocene of Europe, Morlodon vellerei, is described. This new taxon is morphologically close to the Middle Eocene genus Matthodon, with which it shares tendencies towards a robust dentition; the two genera also share the reduction of P1. In order to examine the phylogenetic relationships of the new genus Morlodon with Early and Middle Eocene European Proviverrinae, a phylogenetic analysis of the earliest hyaenodontidans was conducted. The taxa analysed range from Late Palaeocene to Middle Eocene and are from Africa, Asia, Europe and North America. The new phylogeny of earliest hyaenodontans clarifies the systematics of the paraphyletic assemblage \u2018Proviverrinae\u2019 and results in the recognition of five major clades. The monophyly of the Limnocyoninae and Koholiinae is supported, and two new subfamilies are erected from the \u2018Proviverrinae\u2019: Sinopaninae and Arfianinae. A new definition of the Proviverrinae is proposed: only European hyaenodontidans from Early and Middle Eocene are included in this subfamily. However, the phylogenetic relationships between the five subfamilies remain to be established. An ancestral morphotype for the Hyaenodontida is proposed in order to identify the different subfamilies. On the basis of the analysis and of data presently available, an African origin for Hyaenodontida is proposed. Hyaenodontidans are involved in the faunal dispersals that occurred around the Palaeocene\u2013Eocene (P/E) boundary. They dispersed from Africa to Asia during the Late Palaeocene (Limnocyoninae), and at the P/E boundary from Africa to Europe (Proviverrinae) and to North America through Europe (Sinopaninae and Arfianinae). Proviverrinae remain an endemic European group, whereas Sinopaninae, Limnocyoninae and Arfianinae mainly evolved in North America. Koholiinae represents the sole endemic African group. The probable African origin of the Hyaenodontida supports the diphyletism of \u2018Creodonta\u2019 and abandonment of this taxon. http://zoobank.org/urn:lsid:zoobank.org:pub:450D4FAB-42F0-4824-9DE0-DEED591C0D14", "keyphrases": ["early eocene", "phylogeny", "hyaenodontidan", "proviverrinae"]}
{"id": "10.1029/2003PA000915", "title": "Respiration, dissolution, and the lysocline", "abstract": "[1]\u00a0Here I synthesize the results of several types of measurements of organic carbon respiration and calcium carbonate dissolution rates in pelagic seafloor sediments. Measurements of pore water oxygen demonstrate that most of the respiration takes place very near the sediment-water interface, with a scale depth of a few millimeters. The remainder of the oxic respiration occurs much deeper in the sediments, with a scale depth of several centimeters. All measures of respiration from locations as disparate as the tropical Pacific and Atlantic, and the subtropical North Atlantic agree that pelagic seafloor rates of oxic respiration of organic carbon are relatively independent of depth and location, with the exception of sediments beneath the Pacific eastern equatorial upwelling zone. Calcite dissolution in seafloor sediments requires forcing by respiration-produced CO2, and rates are consistent with a first-order dependence on pore water undersaturation, solubility as determined by Mucci [1983] at atmospheric pressure, and locally variable mass-specific dissolution rate constants. Respiration-driven calcite dissolution fluxes predicted by this combination of respiration and dissolution rate expressions are significantly lower than many previous estimates. Comparison of dissolution fluxes in the oligotrophic open ocean measured by other researchers with benthic chamber incubation techniques with those predicted by this combination of rate expressions is, within stated uncertainties, in agreement in all but one case, questioning the need for complicated mechanisms such as surface buffering or authigenic precipitation to explain seafloor calcite diagenesis. Applying these kinetics to a simple one-dimensional, steady state model of the bulk calcite content and sediment accumulation rates of the sediment mixed layer yields results consistent with observations of the seafloor lysocline, the region of transition from high calcite to low-calcite sediments, on the Ceara Rise in the western tropical North Atlantic and the Ontong-Java Plateau in the western equatorial Pacific. Scenarios ignoring dissolution driven by respiration-produced CO2 in pore waters and using the high-order dependence on undersaturation and very large dissolution rate constants implied by some earlier laboratory studies do not simulate these observations. While the scheme represented here does, in fact, imply a strong shift in the locus of carbonate dissolution toward the sediment water interface as bottom-water saturation decreases, as implied by the observations of Martin et al. [2000], no simple combination of sediment transport coefficients and reaction kinetics can reproduce the observation of increasing 14C age as dissolution progresses. These results emphasize the importance of accurate knowledge of the kinetics of respiration and dissolution to interpretation of either the present-day or paleolysocline.", "keyphrases": ["dissolution", "lysocline", "carbonate dissolution", "seafloor sediment", "respiration"]}
{"id": "paleo.004145", "title": "Computational biomes: The ecometrics of large mammal teeth", "abstract": "As organisms are adapted to their environments, assemblages of taxa can be used to describe environments in the present and in the past. Here, we use a data mining method, namely redescription mining, to discover and analyze patterns of association between large herbivorous mammals and their environments via their functional traits. We focus on functional properties of animal teeth, characterized using a recently developed dental trait scoring scheme. The teeth of herbivorous mammals serve as an interface to obtain energy from food, and are therefore expected to match the types of plant food available in their environment. Hence, dental traits are expected to carry a signal of environmental conditions. We analyze a global compilation of occurrences of large herbivorous mammals and of bioclimatic conditions. We identify common patterns of association between dental traits distributions and bioclimatic conditions and discuss their implications. Each pattern can be considered as a computational biome. Our analysis distinguishes three global zones, which we refer to as the boreal-temperate moist zone, the tropical moist zone and the tropical-subtropical dry zone. The boreal-temperate moist zone is mainly characterized by seasonal cold temperatures, a lack of hypsodonty and a high share of species with obtuse lophs. The tropical moist zone is mainly characterized by high temperatures, high isothermality, abundant precipitation and a high share of species with acute rather than obtuse lophs. Finally, the tropical dry zone is mainly characterized by a high seasonality of temperatures and precipitation, as well as high hypsodonty and horizodonty. We find that the dental traits signature of African rain forests is quite different from the signature of climatically similar sites in North America and Asia, where hypsodont species and species with obtuse lophs are mostly absent. In terms of climate and dental signatures, the African seasonal tropics share many similarities with Central-South Asian sites. Interestingly, the Tibetan plateau is covered both by redescriptions from the tropical-subtropical dry group and by redescriptions from the boreal-temperate moist group, suggesting a combination of features from both zones in its dental traits and climate.", "keyphrases": ["computational biome", "tooth", "evolutionary framework", "palaeobiology", "functional interpretation"]}
{"id": "paleo.008003", "title": "Paoliida, a Putative Stem-Group of Winged Insects: Morphology of New Taxa from the Upper Carboniferous of Poland", "abstract": "New representatives of a stem group Paoliida attributed to family Paoliidae (Insecta: Protoptera) are described from the Upper Carboniferous (Langsettian) sphero-sideritic concretions of the Upper Silesian Coal Basin (USCB) in Poland. Zdenekia silesiensis sp. nov. is based on forewing venation and supplemented by material of isolated hindwing similar in venation pattern. Darekia sanguinea gen. et sp. nov. differs from all other paoliid genera by the presence of a short contact between veins MP and CuA behind the division CuA and CuP. Composition of insect fauna exhibits high abundance of paoliid insects in the early Late Carboniferous ecosystems known also from other European localities such as Hagen Vorhalle in Ruhr Basin (Germany), and South Limbourg (Belgium and the Netherlands). It is the first record of true paoliids from the Polish part of paralic USCB supplementing a single historical record of Stygne roemeri considered as a taxon closely related to Paoliidae. The high abundance of paoliid insects from sphero-sideritic concretions in Sosnowiec and coal deposits previously known from the Czech part of Upper Silesian Coal Basin indicates considerable similarity of both faunas supported as well by their close stratigraphical correlation. Morphology of basal wing parts with remnants of articular sclerites preserved supports neopteran relationships of paoliids. Discovery of the first paoliid immature wing is reported suggesting similar living habitat for larvae and adults.", "keyphrases": ["morphology", "upper carboniferous", "poland"]}
{"id": "paleo.011595", "title": "Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact", "abstract": "Significance Debate lingers over what caused the last mass extinction 66 million years ago, with intense volcanism and extraterrestrial impact the most widely supported hypotheses. However, without empirical evidence for either\u2019s exact environmental effects, it is difficult to discern which was most important in driving extinction. It is also unclear why recovery of biodiversity and carbon cycling in the oceans was so slow after an apparently sudden extinction event. In this paper, we show (using boron isotopes and Earth system modeling) that the impact caused rapid ocean acidification, and that the resulting ecological collapse in the oceans had long-lasting effects for global carbon cycling and climate. Our data suggest that impact, not volcanism, was key in driving end-Cretaceous mass extinction. Mass extinction at the Cretaceous\u2013Paleogene (K-Pg) boundary coincides with the Chicxulub bolide impact and also falls within the broader time frame of Deccan trap emplacement. Critically, though, empirical evidence as to how either of these factors could have driven observed extinction patterns and carbon cycle perturbations is still lacking. Here, using boron isotopes in foraminifera, we document a geologically rapid surface-ocean pH drop following the Chicxulub impact, supporting impact-induced ocean acidification as a mechanism for ecological collapse in the marine realm. Subsequently, surface water pH rebounded sharply with the extinction of marine calcifiers and the associated imbalance in the global carbon cycle. Our reconstructed water-column pH gradients, combined with Earth system modeling, indicate that a partial \u223c50% reduction in global marine primary productivity is sufficient to explain observed marine carbon isotope patterns at the K-Pg, due to the underlying action of the solubility pump. While primary productivity recovered within a few tens of thousands of years, inefficiency in carbon export to the deep sea lasted much longer. This phased recovery scenario reconciles competing hypotheses previously put forward to explain the K-Pg carbon isotope records, and explains both spatially variable patterns of change in marine productivity across the event and a lack of extinction at the deep sea floor. In sum, we provide insights into the drivers of the last mass extinction, the recovery of marine carbon cycling in a postextinction world, and the way in which marine life imprints its isotopic signal onto the geological record.", "keyphrases": ["chicxulub impact", "mass extinction", "rapid ocean acidification"]}
{"id": "10.1111/j.1502-3885.2008.00071.x", "title": "Extinction chronology and palaeobiology of the cave bear (Ursus spelaeus)", "abstract": "The cave bear (Ursus spelaeus) was one of several spectacular megafaunal species that became extinct in northern Eurasia during the late Quaternary. Vast numbers of their remains have been recovered from many cave sites, almost certainly representing animals that died during winter hibernation. On the evidence of skull anatomy and low \u03b415N values of bone collagen, cave bears appear to have been predominantly vegetarian. The diet probably included substantial high quality herbaceous vegetation. In order to address the reasons for the extinction of the cave bear, we have constructed a chronology using only radiocarbon dates produced directly on cave bear material. The date list is largely drawn from the literature, and as far as possible the dates have been audited (screened) for reliability. We also present new dates from our own research, including results from the Urals. U. spelaeus probably disappeared from the Alps and adjacent areas \u2013 currently the only region for which there is fairly good evidence \u2013c. 24 000 radiocarbon years BP (c. 27 800\u2003cal. yr BP), approximately coincident with the start of Greenland Stadial 3 (c. 27 500\u2003cal. yr BP). Climatic cooling and inferred decreased vegetational productivity were probably responsible for its disappearance from this region. We are investigating the possibility that cave bear survived significantly later elsewhere, for example in southern or eastern Europe.", "keyphrases": ["palaeobiology", "cave bear", "ursus spelaeus"]}
{"id": "10.1080/14772019.2021.1881177", "title": "A new Late Cretaceous leaf mine Leucopteropsa spiralae gen. et sp. nov. (Lepidoptera: Lyonetiidae) represents the first confirmed fossil evidence of the Cemiostominae", "abstract": "A new fossil leaf mine ichnogenus and species, Leucopteropsa spiralae gen. et sp. nov. (Lepidoptera: Lyonetiidae), from the Upper Cretaceous Kaiparowits Formation (Campanian age, c. 76.6 to 74.5\u2009Ma) in Utah, USA, is the earliest record (75.6\u2009\u00b1\u20090.18\u2009Ma) and only fossil evidence of a lyonetiid-like leaf-mining moth, as well as one of the oldest known fossils within the Yponomeutoidea-Gracillarioidea clade. The blotch-style mine consists of a central oviposition, or egg laying, site with a spiral trail packed with faecal pellets that concentrically spirals outwards. The trail increases in width from oviposition site to terminus, the trajectory of the trail does not cross itself, and there is no apparent pupation chamber present. The morphology of the fossil mine is reliably associated with Cemiostominae and is most similar to mines produced by extant members of the genus Leucoptera, such as the mountain ash bent-wing moth, Leucoptera malifoliella, and the laburnum leaf miner L. laburnella. The leaf-mining moth responsible for L. spiralae may be an early member of the genus Leucoptera or other Cemiostominae genera, and the new ichnogenus Leucopteropsa is erected because the morphology, and therefore the taxonomy, of the moth specifically responsible for L. spiralae mines was not preserved in association with the leaf mine. Despite the phylogenetic analysis of 15 lyonetiids undertaken in this study and the need for further phylogenetic work for the Lepidoptera, particularly the placement of the family Lyonetiidae and the subfamily Cemiostominae within the larger Yponomeutoidea-Gracillarioidea phylogeny, this fossil provides an important Late Cretaceous (\u223c76\u2009Ma) calibration point for lepidopteran phylogeny and serves as an indicator for the antiquity of the most diverse lepidopteran group, Ditrysia. Because lepidopteran body fossils are extremely rare, owing to their small and lightly sclerotized bodies, this discovery also underscores the importance of ichnofossils in the lepidopteran fossil record. http://zoobank.org/urn:lsid:zoobank.org:pub:52B20B15-5C1A-4916-9096-A490DFED7D1C", "keyphrases": ["lepidoptera", "lyonetiidae", "fossil evidence"]}
{"id": "paleo.009505", "title": "Early Gnathostome Phylogeny Revisited: Multiple Method Consensus", "abstract": "A series of recent studies recovered consistent phylogenetic scenarios of jawed vertebrates, such as the paraphyly of placoderms with respect to crown gnathostomes, and antiarchs as the sister group of all other jawed vertebrates. However, some of the phylogenetic relationships within the group have remained controversial, such as the positions of Entelognathus, ptyctodontids, and the Guiyu-lineage that comprises Guiyu, Psarolepis and Achoania. The revision of the dataset in a recent study reveals a modified phylogenetic hypothesis, which shows that some of these phylogenetic conflicts were sourced from a few inadvertent miscodings. The interrelationships of early gnathostomes are addressed based on a combined new dataset with 103 taxa and 335 characters, which is the most comprehensive morphological dataset constructed to date. This dataset is investigated in a phylogenetic context using maximum parsimony (MP), Bayesian inference (BI) and maximum likelihood (ML) approaches in an attempt to explore the consensus and incongruence between the hypotheses of early gnathostome interrelationships recovered from different methods. Our findings consistently corroborate the paraphyly of placoderms, all \u2018acanthodians\u2019 as a paraphyletic stem group of chondrichthyans, Entelognathus as a stem gnathostome, and the Guiyu-lineage as stem sarcopterygians. The incongruence using different methods is less significant than the consensus, and mainly relates to the positions of the placoderm Wuttagoonaspis, the stem chondrichthyan Ramirosuarezia, and the stem osteichthyan Lophosteus\u2014the taxa that are either poorly known or highly specialized in character complement. Given that the different performances of each phylogenetic approach, our study provides an empirical case that the multiple phylogenetic analyses of morphological data are mutually complementary rather than redundant.", "keyphrases": ["jawed vertebrate", "antiarch", "chondrichthyan", "stem gnathostome", "morphological data"]}
{"id": "paleo.006627", "title": "Body Size Distribution of the Dinosaurs", "abstract": "The distribution of species body size is critically important for determining resource use within a group or clade. It is widely known that non-avian dinosaurs were the largest creatures to roam the Earth. There is, however, little understanding of how maximum species body size was distributed among the dinosaurs. Do they share a similar distribution to modern day vertebrate groups in spite of their large size, or did they exhibit fundamentally different distributions due to unique evolutionary pressures and adaptations? Here, we address this question by comparing the distribution of maximum species body size for dinosaurs to an extensive set of extant and extinct vertebrate groups. We also examine the body size distribution of dinosaurs by various sub-groups, time periods and formations. We find that dinosaurs exhibit a strong skew towards larger species, in direct contrast to modern day vertebrates. This pattern is not solely an artefact of bias in the fossil record, as demonstrated by contrasting distributions in two major extinct groups and supports the hypothesis that dinosaurs exhibited a fundamentally different life history strategy to other terrestrial vertebrates. A disparity in the size distribution of the herbivorous Ornithischia and Sauropodomorpha and the largely carnivorous Theropoda suggests that this pattern may have been a product of a divergence in evolutionary strategies: herbivorous dinosaurs rapidly evolved large size to escape predation by carnivores and maximise digestive efficiency; carnivores had sufficient resources among juvenile dinosaurs and non-dinosaurian prey to achieve optimal success at smaller body size.", "keyphrases": ["vertebrate group", "herbivorous dinosaur", "body size distribution"]}
{"id": "paleo.008434", "title": "A perspective on the evidence for keratin protein preservation in fossils: An issue of replication versus validation", "abstract": "The preservation potential of biomolecules within vertebrate integument through deep time has recently been subject to much research and controversy. In particular, the preservation potential of proteins, such as collagen and keratin, is currently debated. Here, we examine claims from a recent study (Schweitzer et al., 2018, PLoS One), which concludes that feather keratin has a high preservation potential. We argue that this work provides insufficient evidence for protein preservation due to issues of methodology and data interpretation. Additionally, we contrast their approach and claims to those of other recently published studies in relation to the question of keratin protein preservation in fossils. We worry that most of the perceived evidence for Mesozoic polypeptide survival stems from repeated replication of methods prone to false detection, rather than triangulation by validating these claims with alternative methods that provide independent lines of evidence. When alternative explanations exist for the evidence cited as support for dinosaur proteins far exceeding their predicted preservation limits, it is most parsimonious to reject the more extreme taphonomic hypotheses. The evidence is instead more consistent with a mode of preservation in which keratinous structures do not fossilize organically as polypeptides, but rather as largely pigment and/or calcium phosphate remnants, which were originally held within the keratin matrix that is now lost. Unsupported taphonomic models (e.g., keratin polypeptide preservation) have the potential to influence our interpretation of fossil data, potentially resulting in erroneous paleobiological or evolutionary conclusions, as illustrated in another recent paper (Pan et al., 2019 , PNAS) that we also discuss.", "keyphrases": ["keratin protein preservation", "issue", "replication", "biomolecule"]}
{"id": "paleo.006128", "title": "Small carbonaceous fossils (SCFs) from North Greenland: new light on metazoan diversity in early Cambrian shelf environments", "abstract": "The Sirius Passet Lagerst\u00e4tte of North Greenland is one of the oldest records of soft\u2010bodied metazoan\u2010dominated ecosystems from the early Cambrian. The Lagerst\u00e4tte site itself is restricted to just a single c. 1\u2010km\u2010long outcrop located offshore from the shelf margin, in an area affected by metamorphic alteration during the Ellesmerian Orogeny (Devonian \u2013 Early Carboniferous). The recent recovery of small carbonaceous fossils (SCFs) to the south, in areas that escaped the effects of this deformation, has substantially expanded the known coverage of organic preservation into shallower water depositional settings in this region. Here, we describe additional SCF assemblages from the siliciclastic shelf succession of the Buen Formation (Cambrian Series 2, stages 3\u20134; c. 515 Ma), expanding the previously documented SCF biota. Newly recovered material indicates a rich diversity of non\u2010mineralizing metazoans, chiefly represented by arthropod remains. These include the filtering and grinding elements of a sophisticated crustacean feeding apparatus (the oldest crustacean remains reported to date), alongside an assortment of bradoriid sclerites, including almost complete, 3D valves, which tie together a number of SCFs previously found in isolation. Other metazoan remains include various trilobite cuticles, diverse scalidophoran sclerites, and a range of metazoan fragments of uncertain affinity. This shallower water assemblage differs substantially from the Sirius Passet biota, which is dominated by problematic euarthropod stem\u2010group members and sponges. Although some of these discrepancies are attributable to taphonomic or temporal factors, these lateral variations in taxonomic composition also point to significant palaeoenvironmental and/or palaeoecological controls on early Cambrian metazoan communities.", "keyphrases": ["north greenland", "scf assemblage", "crustacean", "small carbonaceous fossil"]}
{"id": "paleo.002443", "title": "Anthropologically introduced biases in natural history collections, with a case study on the invertebrate paleontology collections from the middle Cambrian Spence Shale Lagerst\u00e4tte", "abstract": "Natural history collections are critical for modern scientific investigations, which are greatly expanding on the potential data applications of historic specimens. However, using these specimens outside their original intent introduces biases and potential misinterpretations. Anthropogenic biases can be introduced at any point during the life of museum specimens, from collection, preparation, and accession, to digitization. These biases can cause significant effects when the user is unaware of the collection context, as specific collection biases are often known anecdotally, but not ubiquitously. In this case study, the University of Kansas collection of Spence Shale Lagerst\u00e4tte material was examined for anthropogenic biases using a collections inventory, interviews with stakeholders, and a literature review. Biases were found related to collector interest, locality preference, and researcher interest and specialization. These biases create a distorted view on the diversity and ecology of the Spence Shale, and need to be considered in future research. Anna F. Whitaker. Department of Chemical and Physical Sciences, University of Toronto Mississauga, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada. annawhitaker01@gmail.com Julien Kimmig. Earth and Mineral Sciences Museum & Art Gallery, Pennsylvania State University, University Park, Pennsylvania, 16802, USA. jkimmig@psu.edu", "keyphrases": ["natural history collection", "case study", "anthropogenic bias"]}
{"id": "10.1093/mollus/eyv063", "title": "A review of the ecology, palaeontology and distribution of atlantid heteropods (Caenogastropoda: Pterotracheoidea: Atlantidae)", "abstract": "Fewer than 1% of marine gastropod species live a holoplanktic life. Of these, the shelled heteropods of the family Atlantidae are among the most poorly understood. The atlantids potentially make up an important part of the ocean zooplankton, composing up to 69% of shelled holoplanktic gastropods in the Late Pleistocene to Recent fossil record. They are also likely to be at high risk from current and future global changes, including anthropogenic ocean acidification. However, due to their small size (<12 mm), difficulty of sampling and complicated morphology, we still lack key information about atlantid taxonomy and ecology. This makes it difficult to understand how important they are in the ocean foodweb and how they will be affected by environmental change. Although many studies have been carried out on the atlantids, these have generally been broad and unconnected. Here, we draw together this previous research, summarizing what is currently known about atlantid taxonomy, palaeontology, ecology and biogeography, and aiming to provide a foundation for future research on this group. The data indicate complex behaviours involving seasonal and vertical migration, and demonstrate extended geographical ranges, with implications for understanding the role of atlantids in the ocean foodweb and their sensitivity to environmental changes. This review highlights the urgent need for further taxonomic research on the atlantids, including molecular analysis, and for improved sampling techniques.", "keyphrases": ["ecology", "palaeontology", "heteropod", "atlantidae", "recent fossil record"]}
{"id": "10.1086/319574", "title": "Trifoliolate Leaves of Platanus bella (Heer) comb. n. from the Paleocene of North America, Greenland, and Asia and Their Relationships among Extinct and Extant Platanaceae", "abstract": "Trifoliolate leaves of Platanus bella (Heer) comb. n., a species previously known only from the Paleocene of western Greenland, are newly recognized from the Paleocene of northern Wyoming, U.S.A., and Altai of Xinjiang Province, northwestern China, indicating that the species was circumboreal in the early Tertiary. Epidermal anatomy preserved in specimens from all three areas confirms that these compound leaves belong to the Platanaceae. Platanus bella (Heer) comb. n. differs from modern species of Platanus but resembles the European Tertiary species Platanus fraxinifolia (Johnson & Gilmore) Walther and Platanus neptuni (Ettingshausen) B\u016f\u017eek, Hol\u00fd & Z. Kva\u010dek, in the presence of large peltate glandular trichomes. We erect a new subgenus, Glandulosa, to accommodate P. bella, P. fraxinifolia, and P. neptuni. Each of these species possesses similar leaf epidermal structure, with the characteristic platanaceous stomatal apparatus and compound hair bases. In addition, the fossils bear peltate glandular trichomes on the epidermal surfaces that are not known among extant Platanus species. Reproductive structures linked to P. neptuni indicate that subgenus Glandulosa is properly placed in the Platanaceae but that it is a distinct clade from those of the extant subgenera Platanus and Castaneophyllum Leroy. We also review the status of the fossil genera Debeya and Dewalquea, to which some Cretaceous and Tertiary leaves of similar morphology have been placed, and reject the use of either of these names to accommodate leaves of subgenus Glandulosa.", "keyphrases": ["platanus bella", "paleocene", "greenland"]}
{"id": "paleo.011687", "title": "Parasites in the Fossil Record: A Cretaceous Fauna with Isopod-Infested Decapod Crustaceans, Infestation Patterns through Time, and a New Ichnotaxon", "abstract": "Parasites are common in modern ecosystems and are also known from the fossil record. One of the best preserved and easily recognisable examples of parasitism in the fossil record concerns isopod-induced swellings in the branchial chamber of marine decapod crustaceans. However, very limited quantitative data on the variability of infestation percentages at the species, genus, and family levels are available. Here we provide this type of data for a mid-Cretaceous (upper Lower Cretaceous, upper Albian) reef setting at Koskobilo, northern Spain, on the basis of 874 specimens of anomurans and brachyurans. Thirty-seven specimens (4.2%), arranged in ten species, are infested. Anomurans are more heavily infested than brachyurans, variability can be high within genera, and a relationship may exist between the number of specimens and infestation percentage per taxon, possibly suggesting host-specificity. We have also investigated quantitative patterns of infestation through geological time based on 88 infested species (25 anomurans, 55 brachyurans, seven lobsters, and one shrimp), to show that the highest number of infested species can be found in the Late Jurassic, also when corrected for the unequal duration of epochs. The same Late Jurassic peak is observed for the percentage of infested decapod species per epoch. This acme is caused entirely by infested anomurans and brachyurans. Biases (taphonomic and otherwise) and causes of variability with regard to the Koskobilo assemblage and infestation patterns through time are discussed. Finally, a new ichnogenus and -species, Kanthyloma crusta, are erected to accommodate such swellings or embedment structures (bioclaustrations).", "keyphrases": ["decapod crustacean", "chamber", "late jurassic", "kanthyloma crusta", "parasite"]}
{"id": "paleo.005066", "title": "Crystallographic orientations of structural elements in skeletons of Syringoporicae (tabulate corals, Carboniferous): implications for biomineralization processes in Palaeozoic corals", "abstract": "The crystallographic orientation of structural elements in skeletons of representatives of Carboniferous Syringoporicae (Auloporida) has been analysed by scanning electron microscopy (SEM), petrographic microscopy and electron backscatter diffraction (EBSD) on specimens from the Iberian Peninsula. The skeletons of the tabulate corals of the Syringoporicae consist of biogenic calcite crystals, and their microstructure is composed of lamellae, fibres and granules, or of a combination of these. Independent of the microstructure, the c\u2010axis is oriented towards the lumen, quasi\u2010perpendicular to the growth direction of the skeleton (perpendicular to the morphological axis lamellae, parallel to fibres). Most phaceloid taxa have a turbostratic distribution, as a biogenic response to prevent the cleavage of crystals. Cerioid and some phaceloid corals, whose microstructure is conditioned by wall elements, do not exhibit turbostratic distribution. Wall elements are determined by the biology of each taxon. Holacanth septal spines are composed of fibres arranged in a cone\u2010shape structure, sometimes clamped to the external part of the corallite and show a complex crystallography. Monacanth septal spines are spindle shaped and composed of bundles of fibres. Tabulae are composed of lamellae. Their development and crystallographic orientation depends on the position of the epithelium in each case. Shared walls are formed by a combination of the walls of two independent corallites with a median lamina, composed of granules; these have a crystallographic orientation between that of the two corallites. The growth of the microstructure is derived by a coordinated stepping mode of growth, similar to other groups of organisms such as molluscs and scleractinians. The nucleation and formation of packages of co\u2010oriented microcrystals suggest a growth mode similar to mineral bridges with a competitive growth mode between each crystal. The growth pattern of corallites suggests that the growth direction is divided into two main components: a horizontal growth direction towards the lumen and a vertical direction towards the top.", "keyphrases": ["structural element", "coral", "crystallographic orientation"]}
{"id": "paleo.004666", "title": "The eomyid rodents (Mammalia) from the Oligocene and Miocene of the Valley of Lakes (Central Mongolia)", "abstract": "We report new discoveries of eomyid rodents from the Valley of Lakes (Central Mongolia) yielded by diverse layers ranging in age from the Early Oligocene (local biozone A) to the Late Miocene (local biozone E). The remains of eomyid rodents are relatively rare compared to other groups of fossil rodents found in the same region. All together, eight taxa have been identified: Eomys cf. orientalis (biozone A), Eomys aff. orientalis and Eomys sp. (biozone B), cf. Asianeomys bolligeri (biozone C), Asianeomys dangheensis (biozones C1 and D), Eomyops/ Leptodontomys sp. and Keramidomys sp. (biozone D1/2), and Omboomys builstynensis gen. nov., sp. nov. (biozone E). A progressive change of dental morphology and size indicates that the genus Asianeomys represents a local evolution of the genus Eomys in Asia, but also suggests the possible existence of a lineage including Eomys cf. orientalis, Eomys aff. orientalis, cf. Asianeomys bolligeri, and Asianeomys dangheensis.", "keyphrases": ["eomyid rodent", "lakes", "central mongolia"]}
{"id": "paleo.001198", "title": "Cope's Rule and Romer's theory: patterns of diversity and gigantism in eurypterids and Palaeozoic vertebrates", "abstract": "Gigantism is widespread among Palaeozoic arthropods, yet causal mechanisms, particularly the role of (abiotic) environmental factors versus (biotic) competition, remain unknown. The eurypterids (Arthropoda: Chelicerata) include the largest arthropods; gigantic predatory pterygotids (Eurypterina) during the Siluro-Devonian and bizarre sweep-feeding hibbertopterids (Stylonurina) from the Carboniferous to end-Permian. Analysis of family-level originations and extinctions among eurypterids and Palaeozoic vertebrates show that the diversity of Eurypterina waned during the Devonian, while the Placodermi radiated, yet Stylonurina remained relatively unaffected; adopting a sweep-feeding strategy they maintained their large body size by avoiding competition, and persisted throughout the Late Palaeozoic while the predatory nektonic Eurypterina (including the giant pterygotids) declined during the Devonian, possibly out-competed by other predators including jawed vertebrates.", "keyphrases": ["gigantism", "eurypterid", "palaeozoic vertebrate", "large body size", "predator"]}
{"id": "10.1111/zoj.12094", "title": "Redescription of the phytosaurs Paleorhinus (\u2018Francosuchus\u2019) angustifrons and Ebrachosuchus neukami from Germany, with implications for Late Triassic biochronology", "abstract": "Phytosaurs are a diverse and morphologically distinctive clade of superficially crocodile-like archosauriforms that had a near global distribution during the Late Triassic. Because their remains are among the most abundant vertebrate remains recovered in many Upper Triassic terrestrial formations, phytosaurs are used extensively in long-range biochronological and biostratigraphic correlations. The biochronologically oldest and earliest branching known phytosaurs include an array of nominal species from the early Late Triassic of the United States, Germany, Poland, Morocco, and India that have been synonymized within the genus Paleorhinus, and subsequently used to define a global \u2018Paleorhinus biochron\u2019. However, recent phylogenetic work suggested that the North American species previously referred to Paleorhinus are paraphyletic. Here, we reassess the systematics and anatomy of putative specimens of Paleorhinus from southern Germany. Two well-preserved basal phytosaur skulls from the Blasensandstein (Carnian) of Bavaria form the holotypes of Francosuchus angustifrons and Ebrachosuchus neukami, both of which were synonymized with Paleorhinus by previous workers. We demonstrate that Francosuchus angustifrons shares unique synapomorphies with specimens referred to Paleorhinus bransoni from the Late Triassic of Texas, and thus refer the species to Paleorhinus. By contrast, the longirostrine Ebrachosuchus is highly distinctive in morphology, and our new cladistic analysis of Phytosauria demonstrates that it represents a valid taxon that is more closely related to Phytosauridae than to Paleorhinus. We provide the first autapomorphy-based support for a monophyletic but restricted Paleorhinus (supported by a nodal row on the jugal, and low paired ridges on the squamosal) and confirm that previous broader conceptions of Paleorhinus are likely to be paraphyletic.\u00a0\u00a9 2013 The Linnean Society of London", "keyphrases": ["paleorhinus", "ebrachosuchus neukami", "germany"]}
{"id": "10.1080/02724634.1993.10011511", "title": "Phylogeny of the Crocodylotarsi, with reference to archosaurian and crurotarsan monophyly", "abstract": "ABSTRACT The Crocodylotarsi are a group erected by Benton and Clark (1988) for archosaurs that share the \u201ccrocodile-normal\u201d ankle structure. In this study, the phylogeny of the Crocodylotarsi was re-examined based on study of most relevant fossil material of the early non\u2013crocodyliform members of the clade. Relationships among the major archosaurian taxa (Ornithodira, Ornithosuchidae, and Crocodylotarsi) and their proximal outgroups (Proterochampsidae, Euparkeria) were also considered. The monophyly of the Archosauria, Crurotarsi, and Crocodylotarsi is supported by the current analysis. The Parasuchia are the most plesiomorphic clade within the Crocodylotarsi. The Suchia comprise the crocodylotarsans excluding the phytosaurs. The taxon Prestosuchidae is placed near the base of this clade, as are Lewisuchus and Turfanosuchus dabanensis. The new taxon Rauisuchiformes includes the last common ancestor of Aetosauria and Crocodylia and its descendants. Rauisuchia (new combination) includes Rauisuchidae, Gracil...", "keyphrases": ["crocodylotarsi", "euparkeria", "archosauria", "phylogeny"]}
{"id": "10.1111/j.1469-7998.2007.00365.x", "title": "Hypsodonty in ungulates: an adaptation for grass consumption or for foraging in open habitat?", "abstract": "Hypsodont (i.e. high-crowned) teeth have been interpreted as an indicator of feeding preferences and habitat selection in ungulates. For this reason, the degree of hypsodonty has been used for estimating the diet of ancient taxa and in palaeoenvironmental reconstructions. The goal of this study is to elucidate the relative importance of grass consumption and open habitat foraging in the development of hypsodont teeth, using novel computer techniques of knowledge discovery applied to a dataset of 134 species of artiodactyls and perissodactyls distributed among thirteen families. The results obtained suggest that highcrowned teeth represent an adaptation for feeding in an open habitat, although the minimum threshold of hypsodonty seems to increase with the relative length of the anterior part of the jaw. On the contrary, there is no direct relationship between the degree of hypsodonty and the percentage of grass consumed, except for the correspondence between grazing and dwelling in open habitats. A relatively wide muzzle evidences an adaptation for grass foraging in open and mixed habitats, but there are some non-grazing species from a closed habitat that also show wide muzzles. Thus, the hypsodonty index, combined with the length of the anterior part of the jaw and the width of the muzzle, allows accurate inferences on the ecological preferences of extinct ungulates.", "keyphrases": ["ungulate", "grass consumption", "open habitat", "hypsodont"]}
{"id": "paleo.000369", "title": "First bird footprints from the lower Miocene Ler\u00edn Formation, Ebro Basin, Spain", "abstract": "A new tracksite with bird footprints, found in the Bardenas Reales de Navarra Natural Park (Navarre, Spain), is presented in this study. The footprints are preserved in four sandstone blocks of the Ler\u00edn Formation from the northwest sector of the Ebro Basin. According to the magnetostratigraphic data, the age of these blocks is 20.4 Ma (Agenian, lower Miocene). The footprints are more than 100 mm in length, mesaxonic, and tridactyl, and have a prominent central pad impression with the digit impressions not jointed proximally. These features allow classifying them as Uvaichnites riojana. Some of the studied footprints are better preserved than the type series of Uvaichnites, which were found also in the northwest sector of the Ebro Basin. Therefore, the original diagnosis has been emended. Available chronostratigraphic data for these localities as well as for other footprints from China indicate a latest Oligocene-earliest Miocene age (from about 23 to 20 Ma) for Uvaichnites-like footprints. Sedimentological data also indicate similar continental environments, namely perilacustrine deltaic systems and distal alluvial systems. The information about early Miocene avian remains (bones, eggs and footprints) in the Iberian Peninsula is scarce. The skeletal and oological record of this age has been included within the families Phoenicopteridae, Phaisanidae and Cathartidae (or incertae sedis), while the ichnological record was related with trackmakers belonging to Charadriiformes, Ardeidae and Gruidae taxa. For this scenario, in which there are few avian remains, the ichnological diversity shown in this paper complements and improves the knowledge about the Iberian avian diversity in the early Miocene.", "keyphrases": ["bird footprint", "miocene", "ebro basin"]}
{"id": "paleo.012842", "title": "Feeding biomechanics suggests progressive correlation of skull architecture and neck evolution in turtles", "abstract": "The origin of turtles is one of the most long-lasting debates in evolutionary research. During their evolution, a series of modifications changed their relatively kinetic and anapsid skull into an elongated akinetic structure with a unique pulley system redirecting jaw adductor musculature. These modifications were thought to be strongly correlated to functional adaptations, especially to bite performance. We conducted a series of Finite Element Analyses (FEAs) of several species, including that of the oldest fully shelled, Triassic stem-turtle Proganochelys, to evaluate the role of force distribution and to test existing hypotheses on the evolution of turtle skull architecture. We found no support for a relation between the akinetic nature of the skull or the trochlear mechanisms with increased bite forces. Yet, the FEAs show that those modifications changed the skull architecture into an optimized structure, more resistant to higher loads while allowing material reduction on specific regions. We propose that the skull of modern turtles is the result of a complex process of progressive correlation between their heads and highly flexible necks, initiated by the origin of the shell.", "keyphrases": ["progressive correlation", "skull architecture", "turtle", "performance"]}
{"id": "10.1073/pnas.1012722107", "title": "Radiometric dating of the type-site for Homo heidelbergensis at Mauer, Germany", "abstract": "The Mauer mandible, holotype of Homo heidelbergensis, was found in 1907 in fluvial sands deposited by the Neckar River 10 km southeast of Heidelberg, Germany. The fossil is an important key to understanding early human occupation of Europe north of the Alps. Given the associated mammal fauna and the geological context, the find layer has been placed in the early Middle Pleistocene, but confirmatory chronometric evidence has hitherto been missing. Here we show that two independent techniques, the combined electron spin resonance/U-series method used with mammal teeth and infrared radiofluorescence applied to sand grains, date the type-site of Homo heidelbergensis at Mauer to 609 \u00b1 40 ka. This result demonstrates that the mandible is the oldest hominin fossil reported to date from central and northern Europe and raises questions concerning the phyletic relationship of Homo heidelbergensis to more ancient populations documented from southern Europe and in Africa. We address the paleoanthropological significance of the Mauer jaw in light of this dating evidence.", "keyphrases": ["type-site", "homo heidelbergensis", "germany"]}
{"id": "paleo.007706", "title": "A revision of \"pediomyid\" marsupials from the Late Cretaceous of North America", "abstract": "Pediomyids\" are a diverse group of small-to medium-sized marsupials which comprise a significant portion of many Late Cretaceous North American mammalian faunas. Known almost exclusively from isolated teeth and jaw fragments, \"pediomyids\" exhibit far more diversity than any other contemporaneous group of North American mammals. This has led some to suggest that the family \"Pediomyidae\" is an artificial, polyphyletic assemblage composed of multiple lineages that independently acquired various traditionally-recognized \"pediomyid\" molar characters, such as a reduction of the anterior stylar shelf, reduction of the stylocone and a labial shift in the attachment of the cristid obliqua. The present study seeks to elucidate the interrelationships of \"pediomyid\" marsupials and test the monophyly of the group using cladistic methodology, including a broad sampling of Late Cretaceous North American taxa and a comprehensive set of qualitative molar characters. Results suggest that the family \"Pediomyidae\" and the genus \"Pediomys\" are both polyphyletic and are in need of systematic revision. Iqualadelphis lactea (Aquilan) appears to be unrelated to the \"pediomyid\" radiation, and rests as a stem taxon near the base of the cladogram. The large Aquilan Aquiladelphis nests in a trichotomy with a strictly-defined \"Pediomyidae\" and the enigmatic Lancian taxon Glasbius, suggesting the possibility of a distant relationship (above the familial level). Three clades are recognized within the \"Pediomyidae\": a restricted Pediomys, Leptalestes gen. nov. (containing the three smallest species), and Protolambda (containing the remaining three larger species). Results suggest that \"Pediomys\" exiguus is a stem taxon lacking a close relationship to Pediomyidae sensu stricto, and is removed to permit recognition of the family as monophyletic. The results carry implications for the role \"pediomyids\" might have played in the initial North American marsupial radiation sometime prior to the Campanian, and the pattern of molar evolution throughout major Late Cretaceous lineages.", "keyphrases": ["pediomyid", "marsupial", "north american taxa"]}
{"id": "paleo.005824", "title": "Biotic interchange between the Indian subcontinent and mainland Asia through time", "abstract": "Biotic interchange after the connection of previously independently evolving floras and faunas is thought to be one of the key factors that shaped global biodiversity as we see it today. However, it was not known how biotic interchange develops over longer time periods of several million years following the secondary contact of different biotas. Here we present a novel method to investigate the temporal dynamics of biotic interchange based on a phylogeographical meta-analysis by calculating the maximal number of observed dispersal events per million years given the temporal uncertainty of the underlying time-calibrated phylogenies. We show that biotic influx from mainland Asia onto the Indian subcontinent after Eocene continental collision was not a uniform process, but was subject to periods of acceleration, stagnancy and decrease. We discuss potential palaeoenvironmental causes for this fluctuation.", "keyphrases": ["mainland asia", "biota", "biotic interchange", "middle miocene", "molecular phylogenetic data"]}
{"id": "paleo.008994", "title": "The Lithic Assemblages of Xiaochangliang, Nihewan Basin: Implications for Early Pleistocene Hominin Behaviour in North China", "abstract": "Xiaochangliang (XCL), located in the Nihewan Basin of North China, is a key archaeological locality for understanding the behavioural evolution of early humans. XCL dates to ca. 1.36 Ma, making it one of the earliest sites in Northeast Asia. Although XCL represents the first excavation of an Early Pleistocene site in the Nihewan Basin, identified and excavated in the 1970\u2019s, the lithic assemblages have never been published in full detail. Here we describe the lithic assemblages from XCL, providing information on stone tool reduction techniques and the influence of raw materials on artefact manufacture. The XCL hominins used both bipolar and freehand reduction techniques to manufacture small flakes, some of which show retouch. Bipolar reduction methods at XCL were used more frequently than previously recognized. Comparison of XCL with other Early Pleistocene sites in the Nihewan Basin indicates the variable use of bipolar and freehand reduction methods, thereby indicating a flexible approach in the utilization of raw materials. The stone tools from XCL and the Nihewan sites are classifiable as Mode I lithic assemblages, readily distinguished from bifacial industries manufactured by hominins in Eastern Asia by ca. 800 ka.", "keyphrases": ["lithic assemblage", "nihewan basin", "north china"]}
{"id": "paleo.008158", "title": "A skull of a new pelecaniform bird from the Middle Eocene of Messel, Germany", "abstract": "A skull of a new pelecaniform bird is described from the Middle Eocene of Messel (Germany). Masillastega rectirostris gen. et sp. nov. is tentatively referred to the Sulidae (boobies and gannets). If this assignment is correct, the new taxon would represent the earliest fossil record of the family, preceding Sula ronzoni Milne-Edwards, 1867 from the lowermost Oligocene of France by about 15 million years. Masillastega rectirostris most distinctly differs from extant Sulidae in the proportionally longer beak which indicates that the Eocene taxon was not adapted to plunge-diving. Contrary to extant Sulidae, which are exclusively marine birds, Masillastega rectirostris was found in a freshwater deposit. It is the first pelecaniform bird known from Messel and one of the few large birds discovered at this site.", "keyphrases": ["skull", "new pelecaniform bird", "middle eocene", "sulidae"]}
{"id": "10.1098/rspb.2019.2806", "title": "Early Oligocene chinchilloid caviomorphs from Puerto Rico and the initial rodent colonization of the West Indies", "abstract": "By their past and present diversity, rodents are among the richest components of Caribbean land mammals. Many of these became extinct recently. Causes of their extirpation, their phylogenetic affinities, the timing of their arrival in the West Indies and their biogeographic history are all ongoing debated issues. Here, we report the discovery of dental remains from Lower Oligocene deposits (ca 29.5 Ma) of Puerto Rico. Their morphology attests to the presence of two distinct species of chinchilloid caviomorphs, closely related to dinomyids in a phylogenetic analysis, and thus of undisputable South American origin. These fossils represent the earliest Caribbean rodents known thus far. They could extend back to 30 Ma the lineages of some recently extinct Caribbean giant rodents (Elasmodontomys and Amblyrhiza), which are also retrieved here as chinchilloids. This new find has substantial biogeographic implications because it demonstrates an early dispersal of land mammals from South America to the West Indies, perhaps via the emergence of the Aves Ridge that occurred ca 35\u201333 Ma (GAARlandia hypothesis). Considering both this new palaeontological evidence and recent molecular divergence estimates, the natural colonization of the West Indies by rodents probably occurred through multiple and time-staggered dispersal events (chinchilloids, then echimyid octodontoids (spiny rats/hutias), caviids and lastly oryzomyin muroids (rice rats)).", "keyphrases": ["caviomorph", "puerto rico", "colonization"]}
{"id": "paleo.008330", "title": "Intraskeletal histovariability, allometric growth patterns, and their functional implications in bird-like dinosaurs", "abstract": "With their elongated forelimbs and variable aerial skills, paravian dinosaurs, a clade also comprising modern birds, are in the hotspot of vertebrate evolutionary research. Inferences on the early evolution of flight largely rely on bone and feather morphology, while osteohistological traits are usually studied to explore life-history characteristics. By sampling and comparing multiple homologous fore-and hind limb elements, we integrate for the first time qualitative and quantitative osteohistological approaches to get insight into the intraskeletal growth dynamics and their functional implications in five paravian dinosaur taxa, Anchiornis, Aurornis, Eosinopteryx, Serikornis, and Jeholornis. Our qualitative assessment implies a considerable diversity in allometric/isometric growth patterns among these paravians. Quantitative analyses show that neither taxa nor homologous elements have characteristic histology, and that ontogenetic stage, element size and the newly introduced relative element precocity only partially explain the diaphyseal histovariability. Still, Jeholornis, the only avialan studied here, is histologically distinct from all other specimens in the multivariate visualizations raising the hypothesis that its bone tissue characteristics may be related to its superior aerial capabilities compared to the nonavialan paravians. Our results warrant further research on the osteohistological correlates of flight and developmental strategies in birds and bird-like dinosaurs.\nStudying bone histology of extinct paravian dinosaurs (all dinosaurs closer to modern birds than to Oviraptor 1 ) is a powerful tool to infer the biology of these feathered theropods and to better understand the early evolution of birds. Previous studies focusing on ontogenetic stage, growth rate, age, and sexual maturation in dinosaur-bird transitional forms either based their conclusions on the histology of a single element, usually the femur 2-4 , or multiple, but often non-homologous bones were investigated across different studies 5-10 rendering interspecific comparisons difficult. As osteohistological traits vary extensively among different individuals as well as within the skeleton [11] [12] [13] , single-element analyses and comparison of non-homologous bones may lead to different interpretations on the overall growth patterns depending on the elements studied. By contrast, assessing the extent of intraskeletal histovariability gives a more complete picture on ontogenetic stages and growth trajectories, and provides new insights into allometric skeletal growth dynamics and potentially locomotor aspects. Limb morphometrics combined with growth dynamics-related osteohistological traits have been used to infer functional shifts among different elements during the ontogeny in Psittacosaurus 14 . However, up to now, no attempt was made for applying this approach to explore the interelemental dynamics of skeletal development in paravian dinosaurs.\nApart from lineages with secondarily reduced forelimbs, paravian dinosaurs are characterized by disproportionately long and robust arms compared with other theropods. Contrasting with other bipedal dinosaurs, the length of the humerus, radius and ulna in these paravians is comparable with, or may even exceed, that of the femur, and the total forelimb to hind limb length ratio is close to or exceeds one [15] [16] [17] [18] . This implies heterochronic allometry with the fore-and hind limb elements having differential growth rates in different phases of ontogeny, which may also reflect locomotor aspects of the precocial -altricial developmental spectrum of ontogenetic", "keyphrases": ["growth pattern", "bird-like dinosaur", "ontogenetic stage", "intraskeletal histovariability"]}
{"id": "10.1080/02724634.2018.1552156", "title": "Astragalus of Pondaungimys (Rodentia, Anomaluroidea) from the late middle Eocene Pondaung Formation, central Myanmar", "abstract": "ABSTRACT A well-preserved astragalus of the anomaluroid rodent Pondaungimys anomaluropsis is described from the late middle Eocene Pondaung Formation of central Myanmar. This specimen is the first postcranial element of a rodent from the Pondaung Formation and the oldest postcranial fossil currently known for Anomaluroidea. It illuminates plesiomorphous postcranial conditions in early anomaluroids and provides a basis for reconstructing the evolution of arboreal locomotion in this group of rodents. In contrast to those of living anomaluroids, the astragalus of Pondaungimys bears features indicating a less mobile ankle, specifically including a reduced range of plantarflexion at the upper ankle joint and a diminished capacity for inversion at the lower ankle joint. Its anatomy suggests that early anomaluroids were generalized quadrupeds, with intermediate arboreal adaptations between those of paramyids and modern anomaluroids. A cladistic analysis based on astragalar characters corroborates a basal position for Pondaungimys among anomaluroids. The phylogenetic signal derived from astragalar morphology is consistent with recent assessments of relationships among living anomaluroids based on craniodental characters and molecular data. Stem anomaluroids such as Pondaungimys apparently lacked the ability to glide, a locomotor pattern that is retained in extant Zenkerella.", "keyphrases": ["pondaungimys", "anomaluroidea", "astragalus"]}
{"id": "paleo.012299", "title": "Molecular analysis of black coatings and anointing fluids from ancient Egyptian coffins, mummy cases, and funerary objects", "abstract": "Significance Previous studies of ritual black coatings on coffins from ancient Egypt have taken single small samples from objects of wide-ranging time periods and have conflated different types of application. This study takes 100 samples of black ritual liquids identified by type of application and precisely located on the objects, to allow the results to be fully contextualized within the wider discipline. It shows that black coatings on coffins were made using a remarkably consistent selection of natural products. The molecules identified in these black coatings overlap with those used in Egyptian mummification balms, which may suggest a link among separate applications: preparation of the body for burial, decoration of the coffin, and rites performed during the funeral. Black organic coatings and ritual deposits on ancient Egyptian coffins and cartonnage cases are important and understudied sources of evidence about the rituals of funerary practice. Sometimes, the coatings were applied extensively over the surface of the coffin, resembling paint; in other cases, they were poured over the mummy case or wrapped body, presumably as part of a funerary ritual. For this study, multiple samples of black coatings and ritual liquids were taken from 20 Egyptian funerary items dating to a specific time period (c. 943 to 716 BC). Multiple sampling from each object enabled several comparisons to be made: the variability of the black coating within one application, the variability between two applications on one object, and the variability from object to object. All samples were analyzed for lipids using gas chromatography\u2013mass spectrometry (GC-MS), and 51 samples from across the 20 items were further analyzed for the presence of bitumen using solid phase separation followed by selected ion monitoring GC-MS. The majority of the black substances were found to comprise a complex mixture of organic materials, including bitumen from the Dead Sea, conifer resin, and Pistacia resin, providing evidence for a continuation in international trade between Egypt and the eastern Mediterranean after the Late Bronze Age. Both the coating and the anointing liquid are very similar to mummification balms, pointing to parallels with Egyptian embalming rituals and raising questions about the practical aspects of Egyptian funerary practice.", "keyphrases": ["black coating", "ancient egyptian coffin", "mummy case", "lipid"]}
{"id": "paleo.001642", "title": "A revision of European Plesiosminthus (Rodentia, Dipodidae), and new material from the upper Oligocene of Teruel (Spain)", "abstract": "The European record of the rodent genus Plesiosminthus is revised, and two new species are described. Plesiosminthus promyarion is found to be a nomen dubium in the sense of the International Code of Zoological Nomenclature and that name should therefore no longer be used. Until now the genus was hardly known from localities older than MP28; for the first time we describe rich samples from the upper Oligocene (MP 27) of Spain. By now, 10 European species are known, one from the lower Miocene, and the other ones from the upper Oligocene. For most of them it is not possible to establish ancestor-descendant relationships.", "keyphrases": ["european plesiosminthus", "upper oligocene", "stratigraphical range", "mosaic history"]}
{"id": "paleo.006578", "title": "Systematics, morphology, and appendages of Anacheirurus (Pilekiinae, Trilobita) from the Fezouata Shale and the early diversification of Cheiruridae", "abstract": "Pilekiines are the earliest diverging members of the successful trilobite family Cheiruridae. The pilekiine genus Anacheirurus is characterized by sub-quadratic to sub-oval glabella, pitted genae, and a distinct trunk with elongated pleural spines in its posterior part. Anacheirurus adserai is a common component of the Fezouata Shale (Lower Ordovician, Morocco), where it was intially included into several species of the genus Lehua. This assignment and taxonomic over-splitting created confusion, overestimated cheirurid diversity at this locality, and simultaneously underestimated morphological variability within A. adserai. In this contribution we examine new material of A. adserai from the Fezouata Shale, clarifying its morphology and systematics. A detailed re-description of the species shows that Anacheirurus is distinct from Lehua, the latter being a more derived member of Cheiruridae. The comparison of Anacheirurus with other pilekiines shows that morphological variability within this subfamily is mostly constrained to the trunk region. Exceptionally preserved specimens of A. adserai from the Fezouata Shale show details of appendages, revealing the endopodite and exopodite morphologies in early members of Cheiruridae. The endopodite of A. adserai is unique among trilobites in possessing comparatively longer distal podomeres 5 and 6, but otherwise, it has the same general morphology as other described trilobite endopodites. The exopodite morphology of A. adserai shows characters typical of some Cambrian species but differs in several aspects from those known in post-Cambrian taxa. It is concluded that trilobite exopodite morphology was probably more variable than the endopodite morphology, which remains rather conservative across different taxa. Morphological diversity of trilobite exopodites in post-Cambrian taxa might be related to ecological escalations during the Ordovician biodiversification and the transition between Cambrian and Ordovician trilobite faunas.", "keyphrases": ["anacheirurus", "fezouata shale", "cheiruridae", "trilobite", "long locomotory endopod"]}
{"id": "10.1080/02724634.1984.10012024", "title": "The skull and pectoral girdle of the parasemionotid fish Watsonulus eugnathoides from the Early Triassic Sakamena Group of Madagascar, with comments on the relationships of the holostean fishes", "abstract": "ABSTRACT Watsonulus eugnathoides (Piveteau, 1935) is a parasemionotid fish from Early Triassic rocks of Madagascar. The skull and pectoral girdle of this holostean are described from new material. The braincase retains a number of primitive chondrostean-like characters such as an open lateral cranial fissure and frequently open vestibular fontanelle, presence of an endochondral intercalar without membranous outgrowths, and fusion between most of the the endochondral bones in the adult, but is otherwise similar to \u201ccaturids\u201d such as Heterolepidotus. The dermal skull retains one major, putatively primitive, feature shared with chondrosteans, a preopercular with a broad dorsal edge. The dermal shoulder girdle retains a chondrostean-style clavicle, but the endochondral shoulder girdle is most similar to teleosts among actinopterygians. Watsonulus also has an Amia-style jaw joint. The non-reduced clavicle and dorsally expanded preoperculum are lost in all other non-parasemionotid neopte-rygians (the reductions...", "keyphrases": ["skull", "pectoral girdle", "madagascar"]}
{"id": "paleo.001468", "title": "The unexpected survival of an ancient lineage of anseriform birds into the Neogene of Australia: the youngest record of Presbyornithidae", "abstract": "Presbyornithids were the dominant birds in Palaeogene lacustrine assemblages, especially in the Northern Hemisphere, but are thought to have disappeared worldwide by the mid-Eocene. Now classified within Anseriformes (screamers, ducks, swans and geese), their relationships have long been obscured by their strange wader-like skeletal morphology. Reassessment of the late Oligocene South Australian material attributed to Wilaru tedfordi, long considered to be of a stone-curlew (Burhinidae, Charadriiformes), reveals that this taxon represents the first record of a presbyornithid in Australia. We also describe the larger Wilaru prideauxi sp. nov. from the early Miocene of South Australia, showing that presbyornithids survived in Australia at least until ca 22\u2009Ma. Unlike on other continents, where presbyornithids were replaced by aquatic crown-group anatids (ducks, swans and geese), species of Wilaru lived alongside these waterfowl in Australia. The morphology of the tarsometatarsus of these species indicates that, contrary to other presbyornithids, they were predominantly terrestrial birds, which probably contributed to their long-term survival in Australia. The morphological similarity between species of Wilaru and the Eocene South American presbyornithid Telmabates antiquus supports our hypothesis of a Gondwanan radiation during the evolutionary history of the Presbyornithidae. Teviornis gobiensis from the Late Cretaceous of Mongolia is here also reassessed and confirmed as a presbyornithid. These findings underscore the temporal continuance of Australia\u2019s vertebrates and provide a new context in which the phylogeny and evolutionary history of presbyornithids can be examined.", "keyphrases": ["survival", "australia", "presbyornithidae"]}
{"id": "paleo.012537", "title": "Exceptional preservation of mid-Cretaceous marine arthropods and the evolution of novel forms via heterochrony", "abstract": "A \u201cbeautiful chimera\u201d from the mid-Cretaceous sheds light on the evolution of novel forms and forces a rethink of what a crab is. Evolutionary origins of novel forms are often obscure because early and transitional fossils tend to be rare, poorly preserved, or lack proper phylogenetic contexts. We describe a new, exceptionally preserved enigmatic crab from the mid-Cretaceous of Colombia and the United States, whose completeness illuminates the early disparity of the group and the origins of novel forms. Its large and unprotected compound eyes, small fusiform body, and leg-like mouthparts suggest larval trait retention into adulthood via heterochronic development (pedomorphosis), while its large oar-like legs represent the earliest known adaptations in crabs for active swimming. Our phylogenetic analyses, including representatives of all major lineages of fossil and extant crabs, challenge conventional views of their evolution by revealing multiple convergent losses of a typical \u201ccrab-like\u201d body plan since the Early Cretaceous. These parallel morphological transformations may be associated with repeated invasions of novel environments, including the pelagic/necto-benthic zone in this pedomorphic chimera crab.", "keyphrases": ["marine arthropod", "novel form", "crab", "exceptional preservation"]}
{"id": "10.1111/brv.12556", "title": "The deforestation of Easter Island", "abstract": "Easter Island deforestation has traditionally been viewed as an abrupt island\u2010wide event caused by the prehistoric Rapanui civilization, which precipitated its own cultural collapse. This view emerges from early palaeoecological analyses of lake sediments, which showed a sudden and total replacement of palm pollen by grass pollen shortly after Polynesian settlement (800\u20131200 CE). However, further palaeoecological research has challenged this view, showing that the apparent abruptness and island\u2010wide synchronicity of forest removal was an artefact due to the occurrence of a sedimentary gap of several millennia that prevented a detailed record of the replacement of palm\u2010dominated forests by grass meadows. During the last decade, several continuous (gap\u2010free) and chronologically coherent sediment cores encompassing the last millennia have been retrieved and analysed, providing a new picture of forest removal on Easter Island. According to these analyses, deforestation was not abrupt but gradual and occurred at different times and rates, depending on the site. Regarding the causes, humans were not the only factors responsible for forest clearing, as climatic droughts as well as climate\u2013human\u2013landscape feedbacks and synergies also played a role. In summary, the deforestation of Easter Island was a complex process that was spatially and temporally heterogeneous and took place under the actions and interactions of both natural and anthropogenic drivers. In addition, archaeological evidence shows that the Rapanui civilization was resilient to deforestation and remained healthy until European contact, which contradicts the occurrence of a cultural collapse. Further research should aim to obtain new continuous cores and make use of recently developed biomarker analyses to advance towards a holistic view of the patterns, causes and consequences of Easter Island deforestation.", "keyphrases": ["deforestation", "easter island", "drought", "european contact"]}
{"id": "paleo.002863", "title": "Skeletal material from larger Eusauropterygia (Reptilia: Eosauropterygia) with nothosaurian and cymatosaurian affinities from the Lower Muschelkalk of Winterswijk, The Netherlands", "abstract": "Eusauropterygian elements from the Lower Muschelkalk (Vossenveld Formation) of Winterswijk, The Netherlands, comprising three mandibles and a selection of postcranial material, are described. The new mandibles correspond to crania larger than eusauropterygian cranial material previously known from this locality. The postcranial material represents a selection of isolated and associated material of comparably large size. Two of the mandibles conform to the morphology commonly recognized in Nothosaurus from the Lower Muschelkalk, but the third mandible accommodates five fangs per ramus in the symphyseal domain and exhibits a symphyseal ratio of 1.04, a condition not yet described for Eusauropterygia from the Vossenveld Formation. Body length for the animals represented by the finds was estimated through dimensional comparison with MB.R.27, a nearly complete skeleton from the lower Middle Muschelkalk locality of Ru \u00a8dersdorf (Germany) assigned to Nothosaurus marchicus. Body length estimates for the individuals represented by the largest mandible and by a selection of associated postcranial material exceed 1,500 mm; approximately 50 % larger than the eusauropterygian taxa from Winterswijk described so far. Furthermore, certain morphological characters identified in one mandible and in the postcranial elements suggest a cymatosaurian affinity over a nothosaurian affinity. The present study indicates eusauropterygian diversity during the Lower Muschelkalk was greater than traditionally believed. This challenges the concept of a slow paced, gradual biotic response to the origination and expansion of the Muschelkalk Sea, which commenced only 5 million years after the Permian-Triassic mass extinction event.", "keyphrases": ["eusauropterygia", "cymatosaurian affinity", "lower muschelkalk"]}
{"id": "paleo.011779", "title": "Calcified Pulmonary Nodules Identified in a 350-Year-Old-Joseon Mummy: the First Report on Ancient Pulmonary Tuberculosis from Archaeologically Obtained Pre-modern Korean Samples", "abstract": "We found calcified pulmonary nodules in a middle-aged female mummy discovered from 350-yr-old Joseon tomb of Korea. In the CT scan, we found six radiopaque nodules in right lung, through the levels of thoracic vertebrae 1 to 6. We also found presumptive pleural adhesions in right thoracic cavity of CT images. We re-confirmed radiological findings by our post-factum dissection on the same mummy. By the differential diagnosis, we speculate that the radiopaque calcification nodules and associated pleural adhesion could have been caused by tuberculosis. This is the first-ever report on the pulmonary tuberculosis identified in archaeologically obtained, pre-modern Korean samples.", "keyphrases": ["pulmonary nodule", "ancient pulmonary tuberculosis", "pre-modern korean sample"]}
{"id": "10.1080/14772019.2017.1359689", "title": "A new odontocete (toothed cetacean) from the Early Miocene of Peru expands the morphological disparity of extinct heterodont dolphins", "abstract": "A key step in the evolutionary history of Odontoceti (echolocating toothed cetaceans) is the transition from the ancestral heterodont condition \u2013 characterized by the presence of double-rooted cheek teeth bearing accessory denticles \u2013 to the homodont dentition displayed by most extant odontocete species. During the last few decades, new finds and the reassessment of specimens in collections revealed an increased morphological disparity amongst the Oligo\u2013Miocene heterodont odontocetes. Based on a partly articulated skeleton from late Early Miocene (Burdigalian, 18.8\u201318.0 Ma) beds of the Chilcatay Formation (Pisco Basin, Peru), we describe a new genus and species of heterodont odontocete, Inticetus vertizi, in the new family Inticetidae. This large dolphin is characterized by, amongst other things, a long and robust rostrum bearing at least 18 teeth per quadrant; the absence of procumbent anterior teeth; many large, broad-based accessory denticles in double-rooted posterior cheek teeth; a reduced ornament of dental crowns; the styliform process of the jugal being markedly robust; a large fovea epitubaria on the periotic, with a correspondingly voluminous accessory ossicle of the tympanic bulla; and a shortened tuberculum of the malleus. Phylogenetic analyses (with and without molecular constraint; with and without down-weighting of homoplastic characters) yielded contrasting results, with Inticetus falling either as a stem Odontoceti or as an early branching member of a large Platanistoidea clade. With its large size, robust rostrum and unusual dental morphology, and the absence of conspicuous tooth wear, Inticetus increases the morphological and ecological disparity of Late Oligocene\u2013Early Miocene heterodont odontocetes. Finally, this new taxon calls for caution when attempting to identify isolated cetacean cheek teeth, even at the suborder level. http://zoobank.org/urn:lsid:zoobank.org:pub:5B306B49-EB1B-42F9-B755-B0B05B4F938F", "keyphrases": ["odontocete", "cetacean", "early miocene", "phylogenetic analysis"]}
{"id": "10.1093/aob/mct053", "title": "Post-Boreotropical dispersals explain the pantropical disjunction in Paederia (Rubiaceae).", "abstract": "BACKGROUND AND AIMS\nPantropical intercontinental disjunction is a common biogeographical pattern in flowering plants exhibiting a discontinuous distribution primarily in tropical Asia, Africa and the Americas. Only a few plant groups with this pattern have been investigated at the generic level with molecular phylogenetic and biogeographical methods. Paederia (Rubiaceae) is a pantropical genus of 31 species of woody lianas, with the greatest species diversity in continental Asia and Madagascar and only two species from tropical America. The aim of this study was to reconstruct the biogeographical history of Paederia based on phylogenetic analyses to explore how the genus attained its pantropical distribution.\n\n\nMETHODS\nMaximum parsimony and Bayesian inference were used for phylogenetic analyses using sequences of five plastid markers (the rbcL gene, rps16 intron, trnT-F region, atpB-rbcL spacer and psbA-trnH spacer). Biogeographical inferences were based on a Bayesian uncorrelated lognormal relaxed molecular clock together with both Bayesian and likelihood ancestral area reconstructions.\n\n\nKEY RESULTS\nThe data suggest an early diverged Asian lineage sister to the clade of the remaining species consisting of a predominantly Asian sub-clade and a primarily Malagasy sub-clade. Paederia is inferred to have originated in the Oligocene in tropical continental Asia. It then reached Africa in the early to middle Miocene, most probably via long-distance dispersal across the Indian Ocean. The two Neotropical species are inferred to have derived independently in the late Miocene from ancestors of Asia and East Africa, respectively.\n\n\nCONCLUSIONS\nThe results demonstrate the importance of post-Boreotropical long-distance dispersals (across three major oceans) in shaping the global pantropical disjunction in some plants, such as Paederia, with small, winged diaspores adapted to long-distance dispersal by various agents including wind, ocean currents or birds. Overland migration is less likely to explain its palaeotropical disjunction between Asia and Africa.", "keyphrases": ["dispersal", "paederia", "rubiaceae"]}
{"id": "paleo.005495", "title": "A large new leanchoiliid from the Burgess Shale and the influence of inapplicable states on stem arthropod phylogeny", "abstract": "Characterized by atypical frontalmost appendages, leanchoiliids are early arthropods whose phylogenetic placement has been much debated. Morphological interpretations have differed, some of which concern critical characters such as the number of eyes and head appendages, but methodological approaches also have diverged. Here, we describe a new leanchoiliid, Yawunik kootenayi gen. et sp. nov., based on 42 specimens from the newly discovered Marble Canyon locality of the Burgess Shale (Kootenay National Park, British Columbia; middle Cambrian). This new morphotype demonstrates the presence of a four\u2010segmented head in leanchoiliids, along with two small antero\u2010median eyes in addition to lateral eyes. Yawunik is characterized by a 12\u2010segmented trunk and a carinate, lanceolate telson adorned with minute spines. The \u2018great appendages\u2019 of the animal bear teeth on their two distal rami, which would have enhanced their ability to grasp prey. Attitudes of specimens, resulting from burial at multiple aspects of bedding, suggest the \u2018great appendages\u2019 were flexible and capable of antero\u2010posterior rotation. We also discuss the nature of intersegmental tissues and filaments present within the \u2018great appendages\u2019. Our phylogenetic analyses extend the monophyly of leanchoiliids to include Haikoucaris and Yohoia in a new clade, the Cheiromorpha nom. nov. (within Heptopodomera nom. nov.). Other nodes are poorly resolved unless implied weights are used, and in this case, the topology is critically sensitive to the coding prerogative of inapplicable states (NAs). Both the traditional \u2018Arachnomorpha\u2019 hypothesis (NAs as additional states) and the more recently favoured \u2018Artiopoda + Crustacea\u2019 (NAs as uncertainties) were obtained using the same data set and outgroup. This result stresses, first, the historical importance of polarization over data content in scenarios of early arthropod evolution, and second, a pressing need to investigate the impacts of coding inapplicables, especially given the inflating effect of implied weights.", "keyphrases": ["new leanchoiliid", "burgess shale", "arthropod", "phylogeny"]}
{"id": "10.1111/j.1475-4983.2010.01019.x", "title": "Taphonomy and affinity of an enigmatic Silurian vertebrate, Jamoytius kerwoodi White", "abstract": "Abstract:\u2002 The anatomy and affinities of Jamoytius kerwoodi White have long been controversial, because its complex taphonomy makes unequivocal interpretation impossible with the methodology used in previous studies. Topological analysis, model reconstruction and elemental analysis, followed by anatomical interpretation, allow features to be identified more rigorously and support the hypothesis that Jamoytius is a jawless vertebrate. The preserved features of Jamoytius include W\u2010shaped phosphatic scales, 10 or more pairs of branchial openings, optic capsules, a circular, subterminal mouth and a single terminal nasal opening. Interpretations of paired \u2018appendages\u2019 remain equivocal. Phylogenetic analysis places Jamoytius and Euphanerops together (Jamoytiiformes), as stem\u2010gnathostomes rather than lamprey related or sister taxon to Anaspida.", "keyphrases": ["vertebrate", "jamoytius kerwoodi white", "taphonomy"]}
{"id": "paleo.001965", "title": "Taphonomy and affinity of an enigmatic Silurian vertebrate, Jamoytius kerwoodi White", "abstract": "Abstract:\u2002 The anatomy and affinities of Jamoytius kerwoodi White have long been controversial, because its complex taphonomy makes unequivocal interpretation impossible with the methodology used in previous studies. Topological analysis, model reconstruction and elemental analysis, followed by anatomical interpretation, allow features to be identified more rigorously and support the hypothesis that Jamoytius is a jawless vertebrate. The preserved features of Jamoytius include W\u2010shaped phosphatic scales, 10 or more pairs of branchial openings, optic capsules, a circular, subterminal mouth and a single terminal nasal opening. Interpretations of paired \u2018appendages\u2019 remain equivocal. Phylogenetic analysis places Jamoytius and Euphanerops together (Jamoytiiformes), as stem\u2010gnathostomes rather than lamprey related or sister taxon to Anaspida.", "keyphrases": ["vertebrate", "jamoytius kerwoodi white", "taphonomy"]}
{"id": "paleo.011985", "title": "Bird neurocranial and body mass evolution across the end-Cretaceous mass extinction: The avian brain shape left other dinosaurs behind", "abstract": "Ecological or sensory system shifts associated with brain shape and size change may have contributed to unique avian survivorship. Birds today are the most diverse clade of terrestrial vertebrates, and understanding why extant birds (Aves) alone among dinosaurs survived the Cretaceous-Paleogene mass extinction is crucial to reconstructing the history of life. Hypotheses proposed to explain this pattern demand identification of traits unique to Aves. However, this identification is complicated by a lack of data from non-avian birds. Here, we interrogate survivorship hypotheses using data from a new, nearly complete skull of Late Cretaceous (~70 million years) bird Ichthyornis and reassess shifts in bird body size across the Cretaceous-Paleogene boundary. Ichthyornis exhibited a wulst and segmented palate, previously proposed to have arisen within extant birds. The origin of Aves is marked by larger, reshaped brains indicating selection for relatively large telencephala and eyes but not by uniquely small body size. Sensory system differences, potentially linked to these shifts, may help explain avian survivorship relative to other dinosaurs.", "keyphrases": ["mass extinction", "brain shape", "other dinosaur", "extant bird", "ichthyornis"]}
{"id": "10.1111/j.1365-294X.2005.02644.x", "title": "Ancient DNA from pollen: a genetic record of population history in Scots pine", "abstract": "Assessments of plant population dynamics in space and time have depended on dated records of fossil pollen synthesized on a subcontinental scale. Genetic analyses of extant populations have revealed spatial relationships that are indicative of past spatial dynamics, but lack an explicit timescale. Synthesis of these data requires genetic analyses from abundant dated fossil material, and this has hitherto been lacking. Fossil pollen is the most abundant material with which to fill this data gap. Here we report genetic analyses of fossil pollen retrieved from Holtj\u00e4rnen postglacial lake sediment in Sweden and show that plastid DNA is recoverable from Scots Pine and Norway spruce pollen grains that are 100 and 10 000 years old. By sequencing clones from two short plastid PCR products and by using multiple controls we show that the ancient sequences were endogenous to the fossil grains. Comparison of ancient sequences and those obtained from an extant population of Scots pine establishes the first genetic link between extant and fossil samples in this species, providing genetic continuity through time. The finding of one common haplotype present in modern, 100\u2010year old and 10 000\u2010year old samples suggests that it may have persisted near Holtj\u00e4rnen throughout the postglacial period. This retrieval of ancient DNA from pollen has major implications for plant palaeoecology in conifer species by allowing direct estimates of population dynamics in space and time.", "keyphrases": ["pollen", "scots pine", "sweden", "common haplotype", "ancient dna"]}
{"id": "paleo.007203", "title": "Origins and early evolution of arthropods", "abstract": "Phylogenomics reconstructs an arthropod tree in which a monophyletic Arthropoda splits into Pycnogonida + Euchelicerata and Myriapoda + Pancrustacea. The same chelicerate\u2013mandibulate groups are retrieved with morphological data sets, including those encompassing most taxa known from Palaeozoic Konservat\u2010Lagerst\u00e4tten. With respect to the interrelationships of the three extant clades of Panarthropoda, a sister group relationship between Onychophora and Arthropoda is endorsed by transcriptomics and microRNAs, although this hypothesis forces homoplasy in characters of the segmental ganglia that are shared by tardigrades and arthropods. Cambrian lobopodians, dinocaridids, bivalved arthropods and fuxianhuiids document the successive appearance of characteristic arthropod features in the stem lineage of Euarthropoda (crown\u2010group arthropods). Molecular dating suggests that arthropods had their origin and initial diversification in the Ediacaran, but no convincing palaeontological evidence for Panarthropoda is available until the earliest Cambrian.", "keyphrases": ["arthropod", "interrelationship", "phylogeny", "major pancrustacean group", "debate"]}
{"id": "10.5194/cp-13-759-2017", "title": "From monsoon to marine productivity in the Arabian Sea: insights from glacial and interglacial climates", "abstract": "Abstract. The current-climate Indian monsoon is known to boost biological productivity in the Arabian Sea. This paradigm has been extensively used to reconstruct past monsoon variability from palaeo-proxies indicative of changes in surface productivity. Here, we test this paradigm by simulating changes in marine primary productivity for eight contrasted climates from the last glacial\u2013interglacial cycle. We show that there is no straightforward correlation between boreal summer productivity of the Arabian Sea and summer monsoon strength across the different simulated climates. Locally, productivity is fuelled by nutrient supply driven by Ekman dynamics. Upward transport of nutrients is modulated by a combination of alongshore wind stress intensity, which drives coastal upwelling, and by a positive wind stress curl to the west of the jet axis resulting in upward Ekman pumping. To the east of the jet axis there is however a strong downward Ekman pumping due to a negative wind stress curl. Consequently, changes in coastal alongshore stress and/or curl depend on both the jet intensity and position. The jet position is constrained by the Indian summer monsoon pattern, which in turn is influenced by the astronomical parameters and the ice sheet cover. The astronomical parameters are indeed shown to impact wind stress intensity in the Arabian Sea through large-scale changes in the meridional gradient of upper-tropospheric temperature. However, both the astronomical parameters and the ice sheets affect the pattern of wind stress curl through the position of the sea level depression barycentre over the monsoon region (20\u2013150\u00b0\u202fW, 30\u00b0\u202fS\u201360\u00b0\u202fN). The combined changes in monsoon intensity and pattern lead to some higher glacial productivity during the summer season, in agreement with some palaeo-productivity reconstructions.", "keyphrases": ["monsoon", "arabian sea", "upwelling"]}
{"id": "10.1073/pnas.1117039109", "title": "Climate change and the selective signature of the Late Ordovician mass extinction", "abstract": "Selectivity patterns provide insights into the causes of ancient extinction events. The Late Ordovician mass extinction was related to Gondwanan glaciation; however, it is still unclear whether elevated extinction rates were attributable to record failure, habitat loss, or climatic cooling. We examined Middle Ordovician-Early Silurian North American fossil occurrences within a spatiotemporally explicit stratigraphic framework that allowed us to quantify rock record effects on a per-taxon basis and assay the interplay of macrostratigraphic and macroecological variables in determining extinction risk. Genera that had large proportions of their observed geographic ranges affected by stratigraphic truncation or environmental shifts at the end of the Katian stage were particularly hard hit. The duration of the subsequent sampling gaps had little effect on extinction risk, suggesting that this extinction pulse cannot be entirely attributed to rock record failure; rather, it was caused, in part, by habitat loss. Extinction risk at this time was also strongly influenced by the maximum paleolatitude at which a genus had previously been sampled, a macroecological trait linked to thermal tolerance. A model trained on the relationship between 16 explanatory variables and extinction patterns during the early Katian interval substantially underestimates the extinction of exclusively tropical taxa during the late Katian interval. These results indicate that glacioeustatic sea-level fall and tropical ocean cooling played important roles in the first pulse of the Late Ordovician mass extinction in Laurentia.", "keyphrases": ["late", "ordovician mass extinction", "thermal tolerance"]}
{"id": "10.1029/2007PA001502", "title": "A 28\u2010ka history of sea surface temperature, primary productivity and planktonic community variability in the western Arabian Sea", "abstract": "[1]\u00a0Uranium series radionuclides and organic biomarkers, which represent major groups of planktonic organisms, were measured in western Arabian Sea sediments that span the past 28 ka. Variability in the past strength of the southwest and northeast monsoons and its influence on primary productivity, sea surface temperature (SST), and planktonic community structure were investigated. The average alkenone-derived SST for the last glacial period was \u223c3\u00b0C lower than that measured for the Holocene. Prior to the deglacial, the lowest SSTs coincide with the highest measured fluxes of organic biomarkers, which represent primarily a planktonic suite of diatoms, coccolithophorids, dinoflagellates, and zooplankton. We propose that intensification of winter northeast monsoon winds during the last glacial period resulted in deep convective mixing, cold SSTs and enhanced primary productivity. In contrast, postdeglacial (<17 ka) SSTs are warmer during times in which biomarker fluxes are high. Associated with this transition is a planktonic community structure change, in which the ratio of the average cumulative flux of diatom biomarkers to the cumulative flux of coccolithophorid biomarkers is twice as high during the deglacial and Holocene than the average ratio during the last glacial period. We suggest that this temporal transition represents a shift from a winter northeast monsoon-dominated (pre-17 ka) to a summer southwest monsoon-dominated (post-17 ka) wind system.", "keyphrases": ["sea surface temperature", "primary productivity", "glacial period"]}
{"id": "paleo.007637", "title": "Cranial Growth and Variation in Edmontosaurs (Dinosauria: Hadrosauridae): Implications for Latest Cretaceous Megaherbivore Diversity in North America", "abstract": "The well-sampled Late Cretaceous fossil record of North America remains the only high-resolution dataset for evaluating patterns of dinosaur diversity leading up to the terminal Cretaceous extinction event. Hadrosaurine hadrosaurids (Dinosauria: Ornithopoda) closely related to Edmontosaurus are among the most common megaherbivores in latest Campanian and Maastrichtian deposits of western North America. However, interpretations of edmontosaur species richness and biostratigraphy have been in constant flux for almost three decades, although the clade is generally thought to have undergone a radiation in the late Maastrichtian. We address the issue of edmontosaur diversity for the first time using rigorous morphometric analyses of virtually all known complete edmontosaur skulls. Results suggest only two valid species, Edmontosaurus regalis from the late Campanian, and E. annectens from the late Maastrichtian, with previously named taxa, including the controversial Anatotitan copei, erected on hypothesized transitional morphologies associated with ontogenetic size increase and allometric growth. A revision of North American hadrosaurid taxa suggests a decrease in both hadrosaurid diversity and disparity from the early to late Maastrichtian, a pattern likely also present in ceratopsid dinosaurs. A decline in the disparity of dominant megaherbivores in the latest Maastrichtian interval supports the hypothesis that dinosaur diversity decreased immediately preceding the end Cretaceous extinction event.", "keyphrases": ["dinosauria", "north america", "hadrosaurid", "edmontosaurus"]}
{"id": "paleo.003495", "title": "First report on the occurrence of Neseuretinus and Ovalocephalus trilobites in the Middle Ordovician of Iran", "abstract": "In the Derenjal Mountains of east Central Iran, the upper part of the Shirgesht Formation (uppermost Darriwilian) contains a distinct trilobite assemblage that includes Neseuretinus birmanicus and Ovalocephalus aff. obsoletus among others. Both genera were previously unknown in Iran. The occurrence of Ovalocephalus represents the earliest sign of westward taxon migration from China towards higher latitudes along the West Gondwanan margin, which may be related to global warming, after a short episode of cooler climate in the early to mid Darriwilian. Patterns of biogeographical distribution of Ovalocephalus and Neseuretinus suggest that Central Iran was part of an \"overlap zone\" where tropical and high latitude benthic taxa mingled.", "keyphrases": ["neseuretinus", "ovalocephalus", "middle ordovician"]}
{"id": "paleo.008653", "title": "A NEW SPECIES OF MOERITHERIUM (PROBOSCIDEA, MAMMALIA) FROM THE EOCENE OF ALGERIA: NEW PERSPECTIVES ON THE ANCESTRAL MORPHOTYPE OF THE GENUS", "abstract": "Abstract:\u2002 A new species of Moeritherium (Proboscidea, Mammalia), M.\u2003chehbeurameuri sp. nov., is described from remains discovered in the early late Eocene locality of Bir El Ater, Algeria. Although mainly represented by isolated teeth, it shows distinct synapomorphies which justify its attribution to the genus Moeritherium, together with exclusive features that led to the creation of the new species. The main characteristic of this new taxon is the almost complete lophodonty shown by its molars, while Moeritherium is commonly regarded as a bunolophodont to bunodont taxon. In addition to this lophodonty, this new taxon shows anatomical features as yet unknown for the genus, but often met within lophodont early proboscidean taxa such as Phosphatherium escuilliei and Numidotherium koholense. Although a revision of the whole genus Moeritherium is outside the scope of this paper, the main controversies and discussion about the definition of species within the genus Moeritherium are discussed. The surprising lophodonty of M.\u2003chehbeurameuri, together with its small size, its early late Eocene age and the weak molarization of its P3 support the hypothesis of a lophodont hypothetical ancestor for moeritheres, and therefore strengthen the growing hypothesis of a lophodont dental ancestral morphotype for proboscideans.", "keyphrases": ["moeritherium", "mammalia", "ancestral morphotype", "lophodont"]}
{"id": "10.1111/brv.12038", "title": "Faunal turnover of marine tetrapods during the Jurassic\u2013Cretaceous transition", "abstract": "Marine and terrestrial animals show a mosaic of lineage extinctions and diversifications during the Jurassic\u2013Cretaceous transition. However, despite its potential importance in shaping animal evolution, few palaeontological studies have focussed on this interval and the possible climate and biotic drivers of its faunal turnover. In consequence evolutionary patterns in most groups are poorly understood. We use a new, large morphological dataset to examine patterns of lineage diversity and disparity (variety of form) in the marine tetrapod clade Plesiosauria, and compare these patterns with those of other organisms. Although seven plesiosaurian lineages have been hypothesised as crossing the Jurassic\u2013Cretaceous boundary, our most parsimonious topology suggests the number was only three. The robust recovery of a novel group including most Cretaceous plesiosauroids (Xenopsaria, new clade) is instrumental in this result. Substantial plesiosaurian turnover occurred during the Jurassic\u2013Cretaceous boundary interval, including the loss of substantial pliosaurid, and cryptoclidid diversity and disparity, followed by the radiation of Xenopsaria during the Early Cretaceous. Possible physical drivers of this turnover include climatic fluctuations that influenced oceanic productivity and diversity: Late Jurassic climates were characterised by widespread global monsoonal conditions and increased nutrient flux into the opening Atlantic\u2010Tethys, resulting in eutrophication and a highly productive, but taxonomically depauperate, plankton. Latest Jurassic and Early Cretaceous climates were more arid, resulting in oligotrophic ocean conditions and high taxonomic diversity of radiolarians, calcareous nannoplankton and possibly ammonoids. However, the observation of discordant extinction patterns in other marine tetrapod groups such as ichthyosaurs and marine crocodylomorphs suggests that clade\u2010specific factors may have been more important than overarching extrinsic drivers of faunal turnover during the Jurassic\u2013Cretaceous boundary interval.", "keyphrases": ["jurassic\u2013cretaceous transition", "plesiosaurian lineage", "faunal turnover", "polycotylidae", "marine reptile"]}
{"id": "10.2307/1381862", "title": "Mammals as a Key to Evolutionary Theory", "abstract": "Mammalogy provides exceptionally fertile grounds for advancing evolutionary theory, because its data spans from diverse researches on living forms to a rich fossil record. I illustrate this by integrating interdisciplinary evidence and hypotheses in the habitat theory, including : 1) the context of paleoclimatic changes, and how species' distributions responded to them; 2) geographical biases in turnover rates of species; 3) the turnover-pulse hypothesis; 4) breadth of resource use as a cause of phylogenetic turnover rates. Preliminary tests using the late Neogene records of the Americas and Africa suggest that major aspects of the Great American Interchange have parallels in the African record, as predicted by the habitat theory", "keyphrases": ["evolutionary theory", "habitat theory", "turnover-pulse hypothesis"]}
{"id": "paleo.003389", "title": "Retention of fish-like odontode overgrowth in Permian tetrapod dentition supports outside-in theory of tooth origins", "abstract": "Teeth are often thought of as structures that line the margins of the mouth; however, tooth-like structures called odontodes are commonly found on the dermal bones of many Palaeozoic vertebrates including early jawless fishes. \u2018Odontode\u2019 is a generalized term for all tooth-like dentine structures that have homologous tissues and development. This definition includes true teeth and the odontodes of early \u2018fishes\u2019, which have been recently examined to gain new insights into the still unresolved origin of teeth. Two leading hypotheses are frequently referenced in this debate: the \u2018outside-in\u2019 hypothesis, which posits that dermal odontodes evolutionarily migrate into the oral cavity, and the \u2018inside-out\u2019 hypothesis, which posits that teeth originated in the oropharyngeal cavity and then moved outwards into the oral cavity. Here, we show that, unlike the well-known one-to-one replacement patterns of marginal dentition, the palatal dentition of the early Permian tetrapods, including the dissorophoid amphibian Cacops and the early reptile Captorhinus, is overgrown by a new layer of bone to which the newest teeth are then attached. This same overgrowth pattern has been well documented in dermal and oral odontodes (i.e. teeth) of early fishes. We propose that this pattern represents the primitive condition for vertebrates and may even predate the origin of jaws. Therefore, this pattern crosses the fish\u2013tetrapod transition, and the retention of this ancestral pattern in the palatal dentition of early terrestrial tetrapods provides strong support for the \u2018outside-in\u2019 hypothesis of tooth origins.", "keyphrases": ["odontode", "dentition", "tooth origin"]}
{"id": "paleo.005939", "title": "The \u2018Unicorn\u2019 Dinosaur That Wasn\u2019t: A New Reconstruction of the Crest of Tsintaosaurus and the Early Evolution of the Lambeosaurine Crest and Rostrum", "abstract": "The lambeosaurine Tsintaosaurus spinorhinus has traditionally been reconstructed with an elevated, hollow, spike-like crest composed entirely of the nasal bones, although this has been disputed. Here, we provide a new reconstruction of the skull of this species based on reexamination and reinterpretation of the morphology and articular relationships of the type and Paratype skulls and a fragmentary crest. We confirm the presence of a supracranial crest composed of the elevated nasal bones, but also including the premaxillae. We hypothesize that the crest is a tall, lobate, hollow structure that projects dorsally and slightly caudally a distance greater than the height of the skull along the quadrate. In our reconstruction, the nasal passage passes through the crest, but enters the skull rostral to the tubular process of the nasals, not through it. Tsintaosaurus spinorhinus is rediagnosed on the basis of a suite of cranial autapomorphies including a circumnarial fossa subdivided into three accessory fossae, prefrontal with ascending rostral process and lateral flange, nasals fused sagittally to form elongate tubular process that rises dorsally from skull roof, each nasal being expanded rostrocaudally into a rhomboid distal process, and medial processes of premaxillae at the summit of the cranial crest inserted between rhomboid processes of nasals. Tsintaosaurus spinorhinus lacks characters that are present in more derived lambeosaurines (parasaurolophins and lambeosaurins), such as rotation of the caudal margin of the crest to an acute angle with the skull roof, lateral processes of the nasals that enclose part of the intracranial cavity and participate in the formation of the walls of the common median chamber, and a smooth narial fossa lacking ridges and accessory fossae. We hypothesize that ancestrally the rostrum of lambeosaurines may have been more similar to that in Saurolophinae, and became subsequently reduced in complexity during evolution of the group.", "keyphrases": ["new reconstruction", "crest", "rostrum"]}
{"id": "paleo.006308", "title": "Frond orientations with independent current indicators demonstrate the reclining rheotropic mode of life of several Ediacaran rangeomorph taxa", "abstract": "Abstract.\u2014 Fossils from the deep-sea Ediacaran biotas of Newfoundland are among the oldest architecturally complex soft-bodied macroorganisms on Earth. Most organisms in the Mistaken Point\u2013type biotas of Avalonia\u2014particularly the fractal-branching frondose Rangeomorpha\u2014 have been traditionally interpreted as living erect within the water column during life. However, due to the scarcity of documented physical sedimentological proxies associated with fossiliferous beds, Ediacaran paleocurrents have been inferred in some instances from the preferential orientation of fronds. This calls into question the relationship between frond orientation and paleocurrents. In this study, we present an integrated approach from a newly described fossiliferous surface (the \u201cMelrose Surface\u201d in the Fermeuse Formation at Melrose, on the southern portion of the Catalina Dome in the Discovery UNESCO Global Geopark) combining: (1) physical sedimentological evidence for paleocurrent direction in the form of climbing ripple cross-lamination and (2) a series of statistical analyses based on modified polythetic and monothetic clustering techniques reflecting the circular nature of the recorded orientation of Fractofusus misrai specimens. This study demonstrates the reclining rheotropic mode of life of the Ediacaran rangeomorph taxon Fractofusus misrai and presents preliminary inferences suggesting a similar mode of life for Bradgatia sp. and Pectinifrons abyssalis based on qualitative evidence. These results advocate for the consideration of an alternative conceptual hypothesis for position of life of Ediacaran organisms in which they are interpreted as having lived reclined on the seafloor, in the position that they are preserved.", "keyphrases": ["reclining rheotropic mode", "water column", "frond orientation"]}
{"id": "10.1002/ajpa.22657", "title": "Reconstruction of breastfeeding and weaning practices using stable isotope and trace element analyses: A review.", "abstract": "Biogeochemical methods using stable isotopes and trace elements have been increasingly developed and applied to reconstruct modern and ancient breastfeeding and weaning practices of mammals, including humans, because they offer direct proxies for the dietary intake of subadults. Carbon, nitrogen, and oxygen isotopes have been used to evaluate breast milk lipid, protein, and water intake, respectively. Carbon and sulfur isotopes have been used to estimate the content of weaning foods. The elemental concentrations of Sr and Ba in subadult tissues differ because of the dietary change during the weaning process. For analyses, various tissues have been used, such as hair, nail, blood, and feces for modern mammals and bone and teeth for ancient ones. Of these, trace element analysis of tooth enamel offers a good opportunity for the reconstruction of breastfeeding and weaning practices of the more distant past at finer resolution, although further understanding of the metabolism of trace elements is necessary. There are various tissue- and element-specific advantages and disadvantages, and a combination of different proxies can illuminate practices from various viewpoints. Finally, applying the geochemical reconstruction of breastfeeding and weaning practices to human ecology, primatology, and paleoanthropology is important; basic studies of the underlying physiological mechanisms and technical improvements in the analyses will further highlight avenues for future research.", "keyphrases": ["weaning practice", "stable isotope", "tissue", "element analysis"]}
{"id": "10.1080/14772019.2021.1995907", "title": "Northern Eurasian rhinocerotines (Mammalia, Perissodactyla) by the Pliocene\u2013Pleistocene transition: phylogeny and historical biogeography", "abstract": "Pliocene and earliest Pleistocene Northern Eurasian rhinocerotines are poorly documented and understudied in comparison to Pleistocene and Miocene ones. However, they represent a key-group of species for understanding the phylogeny and historical biogeography of their Pleistocene relatives. In the present paper, we revise the abundant material from the late Pliocene locality of Kvabebi, Georgia from a systematic, phylogenetic and palaeobiogeographical perspective. The specimens from Kvabebi are documented by two partially preserved skulls, one mandible and several postcranial remains. Morphological and morphometric comparison with the type material assigned to Pliocene and earliest Pleistocene Northern Eurasian Rhinocerotinae reveal that the specimens from Kvabebi have close affinities with the poorly known Dicerorhinus miguelcrusafonti Gu\u00e9rin & Santaf\u00e9-Llopis, 1978, described from Layna (Spain). The latter species, represented by scanty remains from the Iberian Peninsula, is usually excluded from morphological and morphometrical comparisons and no findings were reported after the 1990s. Pliocene rhinocerotine species have monotonous dental and postcranial morphologies and only a few features allow us to discern the different species. The material from Layna and Kvabebi is somewhat smaller than that of other Pliocene taxa, except for the largest representatives of Stephanorhinus etruscus (Falconer, 1868). Accordingly, the earliest specimens assigned to S. etruscus on morphometric grounds should be revised in the light of the new data here presented. A cladistic analysis performed on 280 characters and 30 species suggests that the emblematic early Pliocene European species, \u2018Dihoplus\u2019 megarhinus (de Christol, 1834), is sister taxon to the Layna and Kvabebi rhinoceroses. Accordingly, both species are here assigned to a new genus named Pliorhinus gen. nov. Although distinct, this clade has close affinities with the paraphyletic genus Stephanorhinus, therefore suggesting the co-occurrence of at least two distinct rhinocerotine lineages raised in the late Miocene interval in Northern Eurasia. http://zoobank.org/urn:lsid:zoobank.org:pub:D3A1AB6D-EFE7-4813-AE74-A27D204A18CA", "keyphrases": ["phylogeny", "historical biogeography", "stephanorhinus etruscus", "northern eurasian rhinocerotine"]}
{"id": "10.1126/science.aac7575", "title": "Deposition, exhumation, and paleoclimate of an ancient lake deposit, Gale crater, Mars", "abstract": "Ancient lake system at Gale crater Since 2012, the Curiosity rover has been diligently studying rocky outcrops on Mars, looking for clues about past water, climate, and habitability. Grotzinger et al. describe the analysis of a huge section of sedimentary rocks near Gale crater, where Mount Sharp now stands (see the Perspective by Chan). The features within these sediments are reminiscent of delta, stream, and lake deposits on Earth. Although individual lakes were probably transient, it is likely that there was enough water to fill in low-lying depressions such as impact craters for up to 10,000 years. Wind-driven erosion removed many of these deposits, creating Mount Sharp. Science, this issue p.10.1126/science.aac7575, see also p. 167 Mount Sharp now stands where there was once a large intercrater lake system. [Also see Perspective by Chan] INTRODUCTION Remote observational data suggest that large bodies of standing water existed on the surface of Mars in its early history. This would have required a much wetter climate than that of the present, implying greater availability of water on a global basis and enhanced potential for global habitability. However, based on assumptions of a vast water inventory and models of atmospheric erosion, theoretical studies suggest a climate that was wetter but not by enough to sustain large lakes, even in depressions such as impact craters. RATIONALE The Mars Science Laboratory mission\u2019s rover, Curiosity, provides the capability to test hypotheses about Mars\u2019s past climate. The focus of the mission is the exploration of a ~5-km-high mountain, Aeolis Mons (informally known as Mount Sharp), located near the center of the ~140-km-wide Gale impact crater. Mount Sharp is underlain by hundreds of meters of sedimentary rock strata deposited ~3.6 billion to 3.2 billion years ago. These sediments accumulated in aqueous environments, recording the history of Mars\u2019s ancient climate. Because of Curiosity\u2019s ability to study these strata where they are exposed near the base of Mount Sharp, we can directly test the hypothesis that large impact craters were capable of accumulating and storing water as lakes for substantial periods of time. RESULTS Over the course of 2 years, Curiosity studied dozens of outcrops distributed along a ~9-km transect that also rose ~75 m in elevation. Image data were used to measure the geometry and grain sizes of strata and to survey the textures associated with sediment deposition and diagenesis. Erosion of Gale\u2019s northern crater wall and rim generated gravel and sand that were transported southward in shallow streams. Over time, these stream deposits advanced toward the crater interior, transitioning downstream into finer-grained (sand-sized), southward-advancing delta deposits. These deltas marked the boundary of an ancient lake where the finest (mud-sized) sediments accumulated, infilling both the crater and its internal lake basin. After infilling of the crater, the sedimentary deposits in Gale crater were exhumed, probably by wind-driven erosion, creating Mount Sharp. The ancient stream and lake deposits are erosional remnants of superimposed depositional sequences that once extended at least 75 m, and perhaps several hundreds of meters, above the current elevation of the crater floor. Although the modern landscape dips northward away from Mount Sharp, the ancient sedimentary deposits were laid down along a profile that projected southward beneath Mount Sharp and indicate that a basin once existed where today there is a mountain. CONCLUSION Our observations suggest that individual lakes were stable on the ancient surface of Mars for 100 to 10,000 years, a minimum duration when each lake was stable both thermally (as liquid water) and in terms of mass balance (with inputs effectively matching evaporation and loss of water to colder regions). We estimate that the stratigraphy traversed thus far by Curiosity would have required 10,000 to 10,000,000 years to accumulate, and even longer if overlying strata are included. Though individual lakes may have come and gone, they were probably linked in time through a common groundwater table. Over the long term, this water table must have risen at least tens of meters to enable accumulation of the delta and lake deposits observed by Curiosity in Gale crater. Inclined strata in the foreground dip southward toward Mount Sharp and represent ancient delta deposits. These deposits transition into strata in the mid-field that were deposited in ancient lakes. The buttes and mesas in the background contain younger deposits that overlie and postdate the lake deposits beneath Mount Sharp. The outcrop in the foreground is about 6 m wide, and the buttes and mesas in the background are hundreds of meters wide and tens of meters high. The image has been white-balanced. [Credit: NASA/Caltech/JPL/MSSS] The landforms of northern Gale crater on Mars expose thick sequences of sedimentary rocks. Based on images obtained by the Curiosity rover, we interpret these outcrops as evidence for past fluvial, deltaic, and lacustrine environments. Degradation of the crater wall and rim probably supplied these sediments, which advanced inward from the wall, infilling both the crater and an internal lake basin to a thickness of at least 75 meters. This intracrater lake system probably existed intermittently for thousands to millions of years, implying a relatively wet climate that supplied moisture to the crater rim and transported sediment via streams into the lake basin. The deposits in Gale crater were then exhumed, probably by wind-driven erosion, creating Aeolis Mons (Mount Sharp).", "keyphrases": ["lake deposit", "gale crater", "mars", "diagenesis"]}
{"id": "10.1086/673861", "title": "Change and Stasis in the Iberian Middle Paleolithic", "abstract": "The European Mousterian has traditionally been portrayed as a long period of technological stasis as opposed to the technotypological dynamism of Upper Paleolithic cultures. The classic debate on Mousterian variability explained interassemblage differences either by ethnic, cultural, functional, and chronological or by paleoenvironmental causes, but variability was based on typological considerations. Recently, technological factors have been introduced in discussions over time trends and geographic differences in the Mousterian. This paper will address the topic by reviewing technological strategies in the Iberian Middle Paleolithic. Three sites from northeastern Spain are chosen as a case study to address the existence of directional patterns in the Iberian Mousterian. We conclude that albeit diachronic variability exists, it does not show patterning, which suggests stochastic variation rather than directional change in the technological strategies of Iberian Neanderthals.", "keyphrases": ["stasis", "iberian middle paleolithic", "strategy"]}
{"id": "paleo.003699", "title": "VARIATIONS IN THE MORPHOLOGY OF EMU (DROMAIUS NOVAEHOLLANDIAE) TRACKS REFLECTING DIFFERENCES IN WALKING PATTERN AND SUBSTRATE CONSISTENCY: ICHNOTAXONOMIC IMPLICATIONS", "abstract": "Abstract:\u2002 Fossil footprints appear in a variety of preservational states, each revealing a different morphology that can give rise to misidentification and misinterpretations. Comparative ichnological work was conducted using living emus (Dromaius novaehollandiae). It was clearly demonstrated that the morphological variation that occurred in footprints of the same animal, walking in the same manner, was caused by variation in substrate consistency. Dry sand substrates are unlikely to preserve any anatomical details of the foot, whereas damp sand or mud of firm consistency preserves a high level of anatomical detail. The finest anatomical details, such as skin impressions, are only preserved in firm mud or clay. In semi\u2010fluid to fluid mud the track walls collapse, destroying the shape of the footprint. Increased speed of progression affects the shape of the footprint dramatically as the distal ends of the digits become more deeply impressed in the substrate during acceleration. Plantigrade stance adopted by the emu while feeding produces highly elongated footprints. Applying these observations to the study of fossil footprints demonstrates that great care should be paid to the original sedimentary conditions at the time of track making, as well as to the stance and gait of the trackmaker.", "keyphrases": ["morphology", "dromaius novaehollandiae", "substrate consistency", "trackmaker"]}
{"id": "10.2307/3514695", "title": "Counting individuals in mammalian fossil assemblages from fluvial environments", "abstract": "Many paleoecological analyses utilize estimates of the relative abundances of taxa in fossil or subfossil assemblages. Such estimates depend upon determination of the number of individuals present or some other measure of the amount of material collected for each taxon. I assess the validity of methods currently used to estimate numbers of individuals per taxon in mammalian assemblages. For any method of counting selected, the underlying assumptions about the probability of association among skeletal elements should correspond to processes of accumulation for the assemblage, as inferred from its taphonomic characteristics. No method is appropriate for all mammalian assemblages. Equating the number of individuals with the number of specimens per taxon is the appropriate method when formerly articulated material has been widely dispersed and has accumulated as isolated specimens. Determining the minimum number of individuals represented by multiple skeletal elements is appropriate when material originally accumulated in articulation. For mammalian assemblages from Middle Siwalik (late Miocene) sediments of Pakistan, different methods of counting are appropriate for assemblages from different sedimentary environments. For assemblages produced by current transport, I counted each specimen as a single individual. For assemblages produced by the activities of predators and scavengers, I determined the minimum number of individuals. Two taphonomic processes that influence the degree of association among skeletal remains are mortality and transport. Taphonomic histories that combine different causes of mortality and different conditions of transport produce fossil assemblages with expected taphonomic characteristics. These include the amount of articulated material, the spatial distribution of specimens, the presence of hydraulic sorting, the frequency of juvenile remains, and patterns of bone damage. Taphonomic characteristics of fossil assemblages do not permit all combinations of mortality and transport to be distinguished. Processes of transport generally obscure taphonomic characteristics imposed by different agents of mortality. INTRODUCTION", "keyphrases": ["fossil assemblage", "environment", "minimum number"]}
{"id": "10.1002/2017PA003237", "title": "Warming and Cooling: The Medieval Climate Anomaly in Africa and Arabia", "abstract": "The Medieval Climate Anomaly (MCA) is a well-recognized climate perturbation in many parts of the world, with a core period of 1000\u20131200\u00a0Common Era. Here we present a palaeotemperature synthesis for the MCA in Africa and Arabia, based on 44 published localities. The data sets have been thoroughly correlated and the MCA trends palaeoclimatologically mapped. The vast majority of available Afro-Arabian onshore sites suggest a warm MCA, with the exception of the southern Levant where the MCA appears to have been cold. MCA cooling has also been documented in many segments of the circum-Africa-Arabian upwelling systems, as a result of changes in the wind systems which were leading to an intensification of cold water upwelling. Offshore cores from outside upwelling systems mostly show warm MCA conditions. The most likely key drivers of the observed medieval climate change are solar forcing and ocean cycles. Conspicuous cold spikes during the earliest and latest MCA may help to discriminate between solar (Oort Minimum) and ocean cycle (Atlantic Multidecadal Oscillation, AMO) influence. Compared to its large share of nearly one quarter of the world's landmass, data from Africa and Arabia are significantly underrepresented in global temperature reconstructions of the past 2,000\u00a0years. Onshore data are still absent for most regions in Africa and Arabia, except for regional data clusters in Morocco, South Africa, the East African Rift, and the Levant coast. In order to reconstruct land palaeotemperatures more robustly over Africa and Arabia, a systematic research program is needed.", "keyphrases": ["medieval climate anomaly", "arabia", "mca"]}
{"id": "10.1080/14772019.2013.852903", "title": "Ontogeny and intraspecific variation of the early Cambrian trilobite Olenellus gilberti, with implications for olenelline phylogeny and macroevolutionary trends in phenotypic canalization", "abstract": "Morphological variation within the Early Cambrian olenelline trilobite Olenellus gilberti from the Pioche Formation of Nevada is partitioned into ontogenetic, static (non-ontogenetic), and taphonomic components, providing clearer understanding of the nature and sources of the variation. Such understanding is crucial for improved systematic, phylogenetic and evolutionary analyses of early trilobites. Compaction caused a significant change in mean form and an increase in shape variance, distorting many aspects of biological shape and shape variation. Morphologically mature specimens exhibited variation in many quantitative and qualitative aspects of cephalic morphology, in the distribution of prothoracic axial nodes, and in the number of opisthothoracic segments. The variance of two log-transformed size measures does not significantly increase over the first five sampled instars, a pattern interpretable either as the oldest known case of targeted growth in animal history, or as evidence of strong selection during early ontogeny. The magnitude of static cephalic shape variation does not significantly change during late ontogeny, also indicative either of developmental regulation of form or of selection against deviant phenotypes. The dominant structure of cephalic static shape variation is similar to the pattern of shape change during late portions of ontogeny: intraspecific heterochrony might therefore have been an important contributor to size-independent shape variation. For many traits, the developmental system was not well buffered against internal and/or external variation so that the resulting phenotype was not tightly canalized in the condition of those traits. Intraspecific variation in such traits is rarely documented in later (especially post-Cambrian) trilobites, consistent with the claim that developmental systems of early trilobites were relatively poorly canalized. However, other aspects of cephalic growth are consistent with having been under tight developmental regulation, which would not be indicative of general developmental \u2018sloppiness\u2019. This cautions against generalizing observations from a limited number of traits to the entire organism.", "keyphrases": ["intraspecific variation", "trilobite", "ontogeny"]}
{"id": "10.1111/j.0031-0239.2004.00388.x", "title": "Cryptospore Assemblages from the Ordovician/silurian Boundary in the Puna Region, North\u2010west Argentina", "abstract": "Palynomorph assemblages have been recovered from deposits believed to straddle the Ordovician/Silurian boundary, from the upper member of the Salar del Rinc\u00f3n Formation, in the Puna region of north\u2010west Argentina. The palynomorph assemblages are dominated by terrestrial cryptospores, but also contain marine elements (acritarchs, prasinophycean algae and chitinozoans). The cryptospore assemblages are similar in composition to those described from coeval deposits worldwide, suggesting that the producers were cosmopolitan and tolerated a wide range of climatic conditions. They are correlated with the Imperfectotriletes spp. Interval Biozone (sub\u2010biozone \u03b1) of the Imperfectotriletes spp.\u2010Laevolancis divellomedia Assemblage Biozone, indicating a Hirnantian (latest Ordovician) age. Acritarchs include late Ordovician species such as Eupoikilosusa striata and Villosacapsula cf. setosapellicula, that coexist with the Llandovery species Dactylofusa estillis. Based on lithological and palynological evidence, an early Llandovery, or a late Hirnantian (post\u2010glacial) age is proposed for the basal part of the upper member of the Salar del Rinc\u00f3n Formation.", "keyphrases": ["ordovician", "silurian boundary", "north\u2010w argentina"]}
{"id": "paleo.007958", "title": "Calcium isotopes offer clues on resource partitioning among Cretaceous predatory dinosaurs", "abstract": "Large predators are overabundant in mid-Cretaceous continental dinosaur assemblages of North Africa. Such unbalanced ecosystem structure involves, among predatory dinosaurs, typical abelisaurid or carcharodontosaurid theropods co-occurring with long-snouted spinosaurids of debated ecology. Here, we report calcium (Ca) isotope values from tooth enamel (expressed as \u03b444/42Ca) to investigate resource partitioning in mid-Cretaceous assemblages from Niger (Gadoufaoua) and Morocco (Kem Kem Beds). In both assemblages, spinosaurids display a distinct isotopic signature, the most negative in our dataset. This distinct taxonomic clustering in Ca isotope values observed between spinosaurids and other predators provides unambiguous evidence for niche partitioning at the top of the trophic chains: spinosaurids foraged on aquatic environments while abelisaurid and carcharodontosaurid theropods relied almost exclusively on terrestrial resources.", "keyphrases": ["resource", "predatory dinosaur", "calcium"]}
{"id": "10.1002/ajpa.23337", "title": "Dental microwear textural analysis as an analytical tool to depict individual traits and reconstruct the diet of a primate.", "abstract": "OBJECTIVES\nDental microwear is a promising tool to reconstruct animals' diet because it reflects the interplay between the enamel surface and the food items recently consumed. This study examines the sources of inter-individual variations in dietary habits in a free-ranging population of mandrills (Mandrillus sphinx) using a combination of feeding monitoring and in vivo dental microwear textural analysis (DMTA).\n\n\nMETHODS\nWe investigated the impact of seasonality and individual traits on four DMTA parameters. In parallel, we further studied the influence of the physical properties of the food items consumed on these four parameters, using three proxies (mechanical properties, estimates of phytolith and external grit contents).\n\n\nRESULTS\nWe found that seasonality, age, and sex all impact DMTA parameters but those results differ depending on the facet analyzed (crushing vs. shearing facets). Three DMTA parameters (anisotropy, complexity, and heterogeneity of complexity) appear sensitive to seasonal variations and anisotropy also differs between the sexes while textural fill volume tends to vary with age. Moreover, the physical properties of the food items consumed vary seasonally and also differ depending on individual sex and age.\n\n\nCONCLUSION\nConsidering the interplay between the tested variables and both dental microwear and diet, we reaffirm that food physical properties play a major role in microwear variations. These results suggest that DMTA parameters may provide valuable hints for paleoecological reconstruction using fragmentary fossil dental remains.", "keyphrases": ["tool", "individual trait", "dmta", "dental microwear"]}
{"id": "paleo.001815", "title": "Tooth histology, attachment, and replacement in the Ichthyopterygia reviewed in an evolutionary context", "abstract": "Ichthyosaurs, an extinct group of Mesozoic marine diapsids, show a relatively small range of tooth crown morphologies. With few exceptions, members of the group bear a large number of conical teeth and show only minor heterodonty within a jaw. This uniformity in gross morphology masks a high degree of variation in both the quantity and arrangement of the mineralized tooth tissues. Here, we describe tooth tissue structure and distribution in derived ichthyosaurs. We synthesize these new observations with the historical literature, to map changes in the quantity and arrangement of tooth tissues. These changes affected tooth attachment, tooth replacement, plicidentine morphology, and the amount and distribution of cellular cementum. The amount of variation detected in features relating to ichthyosaurian dentition is not surprising given the geological longevity and morphological disparity of the group, but does emphasize the importance of extensive taxon sampling in studies of tooth histology and evolution. This study is important in that it incorporates morphological and histological information in a phylogenetic and developmental context, something that is rarely done for marine reptile dentitions.", "keyphrases": ["attachment", "dentition", "tooth histology"]}
{"id": "paleo.000417", "title": "Evolutionary origins and development of saw-teeth on the sawfish and sawshark rostrum (Elasmobranchii; Chondrichthyes)", "abstract": "A well-known characteristic of chondrichthyans (e.g. sharks, rays) is their covering of external skin denticles (placoid scales), but less well understood is the wide morphological diversity that these skin denticles can show. Some of the more unusual of these are the tooth-like structures associated with the elongate cartilaginous rostrum \u2018saw\u2019 in three chondrichthyan groups: Pristiophoridae (sawsharks; Selachii), Pristidae (sawfish; Batoidea) and the fossil Sclerorhynchoidea (Batoidea). Comparative topographic and developmental studies of the \u2018saw-teeth\u2019 were undertaken in adults and embryos of these groups, by means of three-dimensional-rendered volumes from X-ray computed tomography. This provided data on development and relative arrangement in embryos, with regenerative replacement in adults. Saw-teeth are morphologically similar on the rostra of the Pristiophoridae and the Sclerorhynchoidea, with the same replacement modes, despite the lack of a close phylogenetic relationship. In both, tooth-like structures develop under the skin of the embryos, aligned with the rostrum surface, before rotating into lateral position and then attaching through a pedicel to the rostrum cartilage. As well, saw-teeth are replaced and added to as space becomes available. By contrast, saw-teeth in Pristidae insert into sockets in the rostrum cartilage, growing continuously and are not replaced. Despite superficial similarity to oral tooth developmental organization, saw-tooth spatial initiation arrangement is associated with rostrum growth. Replacement is space-dependent and more comparable to that of dermal skin denticles. We suggest these saw-teeth represent modified dermal denticles and lack the \u2018many-for-one\u2019 replacement characteristic of elasmobranch oral dentitions.", "keyphrases": ["saw-teeth", "sawfish", "sawshark", "placoid scale", "oral dentition"]}
{"id": "10.1006/jhev.1997.0141", "title": "Holes and grooves: the contribution of microscopy and taphonomy to the problem of art origins.", "abstract": "Optical and scanning electron microscopy, comparative anatomy, data from modern and Pleistocene carnivore accumulations, and analysis of archeological materials show that some of the pieces interpreted by various scholars as engraved or perforated bones from European Lower and Middle Paleolithic sites (such as Pech de l'Az\u00e9 II, Str\u00e1nska Sk\u00e1la, Kulna, Bois Roche and Cueva Morin) are not early manifestations of non-utilitarian behavior. Putative engravings are in fact vascular grooves, while perforated pieces are partially-digested bones regurgitated by hyenas. The current debate on art origins has often been centered on the symbolic value and cognitive implications of these and similar pieces without a first-hand analysis of the objects to provide convincing demonstration of the human origins of the marks. Such demonstration is a necessary prerequisite to any discussion of their significance for the evolution of symbolic behavior.", "keyphrases": ["groove", "art origin", "object"]}
{"id": "10.1130/SPE243-p187", "title": "Rodents of the Bridgerian (Middle Eocene) Elderberry Canyon Local Fauna of Eastern Nevada", "abstract": "Emry, Robert J., and William W. Korth. Rodents of the Bridgerian (Middle Eocene) Elderberry Canyon Local Fauna of Eastem Nevada. Smithsonian Contributions to Paleobiology, number 67, 14 pages, 5 figures, 1989.\u2014The Elderberry Canyon Local Fauna, presently represented by more than 40 vertebrate taxa, including at least 30 mammals, occurs in carbonate rocks assigned to the Sheep Pass Formation, near Ely, Nevada. Among the mammals, nine rodent species, representing four families, are recognized. Reithroparamys delicatissimus, and R. cf. R. huerfanensis are species previously known from the Rocky Mountain region; Microparamys sambucus and Pauromys exallos are new species assigned to genera commonly occurring in Eocene faimas elsewhere; Elymys complexus is a new genus and species of minute rodent thought to be related to Simimys and questionably assigned to the family Zapodidae; Sciuravus, Mattimys, and Knightomys are represented by material not assignable to species; and another unidentified ischyromyid completes the roster of rodents presently known in the assemblage. The fauna as a whole, and the rodents in particular, share the greatest homotaxial similarity with early Bridgerian (early middle Eocene) faimas elsewhere, allowing a confident early Bridgerian age assignment for the Elderberry Canyon Local Fauna. The composition of this rodent assemblage suggests that faunal interchange was relatively unrestricted from southem California through Nevada to the Rocky Mountain region in Bridgerian time. OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The trilobite Phaecops rana Green. Lilwary of Cwigrcss Cataloging in Publication DaU Emry, Robert J. Rodents of the Bridgerian (middle Eocene) Elderberry Canyon local fauna of Eastern Nevada. (Smithsonian COTitributions to paleobiology ; no. 67) Bibliography p. SupL of Docs, no.: SI 1.30:67 1. Rodents, Fossil\u2014Nevada\u2014Elderberry Canyoa 2. Paleontology\u2014^Eocene. I. Korth, William W. II. Title. III. Series. QE701.S56 no. 67 560 s [569'.323] 89-600114 [QE882.R6]", "keyphrases": ["middle eocene", "eastern nevada", "rodent"]}
{"id": "10.1029/98pa00670", "title": "Direct correlation of millennial\u2010scale changes in western North American vegetation and climate with changes in the California Current System over the past \u223c60 kyr", "abstract": "Terrestrial (pollen) and marine climate proxies from seven sediment cores taken on the continental margin of western North America between 32\u00b0 and 43\u00b0N show systematically related short-term changes superposed on Milankovitch-scale oscillations of the past 60 kyr. During oxygen isotope stage 3, brief warming events in California and Oregon appear correlative with interstadial events in waters offshore, as do the rapid climate oscillations of the last glacial transition (\u223c14\u2013\u223c10 ka). Estimated temperature depression of the coastal lowlands ranges from >10\u00b0C in southern California to \u223c5\u00b0C in Oregon during the last glacial. The absence of long-distance migration of Pacific coastal plant assemblages concurs with marine evidence that southward movement of the polar front during the last glacial maximum was limited. Correlative changes in terrestrial and marine ecosystems imply that broad reorganizations of circulation in the northeast Pacific Ocean were synchronous with reorganizations of atmospheric circulation over western North America.", "keyphrases": ["vegetation", "kyr", "glacial maximum"]}
{"id": "paleo.004345", "title": "New paromomyids (Mammalia, Primates) from the Paleocene of southwestern Alberta, Canada, and an analysis of paromomyid interrelationships", "abstract": "Abstract. Paromomyidae are one of several families of plesiadapiforms that flourished during the Paleocene in North America soon after the extinction of non-avian dinosaurs some 66 million years ago. Although they are often among the best-represented plesiadapiforms in mammalian faunas in both North America and Europe, the early history of paromomyids is poorly understood, and their fossil record at higher latitudes is comparatively depauperate. We report here on the discovery of two new species of paromomyids from Paleocene deposits in southwestern Alberta: Edworthia greggi new species is the second known species of the basal paromomyid Edworthia Fox, Scott, and Rankin, 2010 whereas Ignacius glenbowensis new species is among the most abundantly represented species of Ignacius Matthew and Granger, 1921. These new discoveries document, for the first time, parts of the upper dentition of Edworthia, and the new species of Ignacius represents the first new, pre-Clarkforkian species of the genus to be described in nearly 100 years. A comprehensive phylogenetic analysis of nearly all known paromomyid taxa (including the new species described herein) recovered both species of Edworthia near the base of the paromomyid tree in a polytomy with Paromomys depressidens Gidley, 1923 and a paraphyletic Ignacius. The new paromomyids from Alberta not only increase the known taxonomic diversity of Edworthia and Ignacius but also add significantly to knowledge of the dental anatomy of these poorly known genera and further add to a uniquely Canadian complement of Paleocene plesiadapiforms.", "keyphrases": ["paleocene", "southwestern alberta", "plesiadapiform", "new paromomyid"]}
{"id": "paleo.003698", "title": "Diversity dynamics of Ordovician bryozoa", "abstract": "This study presents a compilation of the temporal distribution of 200 bryozoan genera during the Ordovician. Bryozoans appeared in the earliest Ordovician (Tremadoc), diversified rapidly until the late Sandbian, and then suffered three distinct extinctions in the Late Ordovician. In the early Katian, the first significant extinction eliminated 22.7% of bryozoan genera. That was the highest taxonomic loss in the Ordovician; however, due to high origination rates, the magnitude of this extinction was the lowest among the three extinctions. The second extinction wave occurred in the late Katian, resulting in taxonomic loss of 22.4%. This event can be estimated as the most severe for bryozoans during the Ordovician because of extremely low origination rates what resulted in the highest net decrease of diversity. The third extinction of bryozoans occurred during the Hirnantian resulting in the lowest taxonomic loss (16.5%) and intermediate net decrease of diversity. The diversity dynamics of bryozoans in the Ordovician was apparently controlled by climatic changes, provinciality and food availability.", "keyphrases": ["bryozoa", "sandbian", "diversity dynamic", "ordovician period"]}
{"id": "10.1080/03115511003669944", "title": "The Winton Formation flora (Albian\u2013Cenomanian, Eromanga Basin): implications for vascular plant diversification and decline in the Australian Cretaceous", "abstract": "The youngest Australian equisetaleans and bennettitaleans are identified within the latest Albian to early Cenomanian Winton Formation flora based on new impression fossils from the Winton district, Eromanga Basin, western Queensland. Typical Winton Formation floras are also confirmed near Isisford and Morney Plains in eastern and central Eromanga Basin. The Winton Formation flora contains over 50 macrofossil plant taxa and marks the transition from seed-fern/conifer to angiosperm dominance in the Australian floristic succession. The pattern of clade representation in Australian late Mesozoic fossil assemblages suggests a causal link between angiosperm diversification and the decline of key understorey and mid-storey plants, particularly equisetaleans, seed-ferns, ginkgophytes and some fern families, through the mid-Cretaceous.", "keyphrases": ["winton formation flora", "eromanga basin", "conifer"]}
{"id": "paleo.006362", "title": "The oldest specialized tetrapod herbivore: A new eupelycosaur from the Permian of New Mexico, USA", "abstract": "Gordodon kraineri is a new genus and species of edaphosaurid eupelycosaur known from an associated skull, lower jaw and incomplete postcranium found in the early Permian Bursum Formation of Otero County, New Mexico, USA. It has a specialized dental apparatus consisting of large, chisel-like incisors in the front of the jaws separated by a long diastema from relatively short rows of peg-like maxillary and dentary cheek teeth. The dorsal vertebrae of Gordodon have long neural spines that bear numerous, randomly arranged, small, thorn-like tubercles. The tubercles on long neural spines place Gordodon in the Edaphosauridae, and the dental apparatus and distinctive tubercles on the neural spines distinguish it from the other edaphosaurid genera\u2014Edaphosaurus, Glaucosaurus, Lupeosaurus and Ianthasaurus. Gordodon is the oldest known tetrapod herbivore with a dentary diastema, extending the temporal range of that anatomical feature back 95 million years from the Late Triassic. The dental apparatus of Gordodon indicates significantly different modes of ingestion and intraoral transport of vegetable matter than took place in Edaphosaurus and thus represents a marked increase in disparity among edaphosaurids. There were two very early pathways to tetrapod herbivory in edaphosaurid evolution, one toward generalized browsing on high-fiber plant items (Edaphosaurus) and the other (Gordodon) toward more specialized browsing, at least some of it likely on higher nutrient, low fiber plant items. Gordodon shows a surprisingly early specialization of the dental apparatus and indicates how incomplete our knowledge is of edaphosaurid evolution, disparity and diversity. Spencer G. Lucas. New Mexico Museum of Natural History, 1801 Mountain Road N. W., Albuquerque, 87104 New Mexico, USA. spencer.lucas@state.nm.us Larry F. Rinehart. New Mexico Museum of Natural History, 1801 Mountain Road N. W., Albuquerque, http://zoobank.org/BA32DBE6-21CD-4CA3-A663-CB750B1A723F Lucas, Spencer G., Rinehart, Larry F., and Celeskey, Matthew D. 2018. The oldest specialized tetrapod herbivore: A new eupelycosaur from the Permian of New Mexico, USA. Palaeontologia Electronica 21.3.39A 1-42. https://doi.org/10.26879/899 palaeo-electronica.org/content/2018/2343-new-eupelycosaur Copyright: November 2018 Paleontological Society. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ LUCAS, RINEHART, & CELESKEY: NEW EUPELYCOSAUR 87104 New Mexico, USA. larry.rinehart@earthlink.net Matthew D. Celeskey. New Mexico Museum of Natural History, 1801 Mountain Road N. W., Albuquerque, 87104 New Mexico, USA. matt.celeskey@hmnh.org", "keyphrases": ["tetrapod herbivore", "new eupelycosaur", "gordodon", "edaphosauridae"]}
{"id": "paleo.000559", "title": "Dinosaur Speed Demon: The Caudal Musculature of Carnotaurus sastrei and Implications for the Evolution of South American Abelisaurids", "abstract": "In the South American abelisaurids Carnotaurus sastrei, Aucasaurus garridoi, and, to a lesser extent Skorpiovenator bustingorryi, the anterior caudal ribs project at a high dorsolateral inclination and have interlocking lateral tips. This unique morphology facilitated the expansion of the caudal hypaxial musculature at the expense of the epaxial musculature. Distinct ridges on the ventrolateral surfaces of the caudal ribs of Aucasaurus garridoi are interpreted as attachment scars from the intra caudofemoralis/ilio-ischiocaudalis septa, and confirm that the M. caudofemoralis of advanced South American abelisaurids originated from a portion of the caudal ribs. Digital muscle models indicate that, relative to its overall body size, Carnotaurus sastrei had a substantially larger M. caudofemoralis than any other theropod yet studied. In most non-avian theropods, as in many extant sauropsids, the M. caudofemoralis served as the primary femoral retractor muscle during the locomotive power stroke. This large investment in the M. caudofemoralis suggests that Carnotaurus sastrei had the potential for great cursorial abilities, particularly short-burst sprinting. However, the tightly interlocking morphology of the anterior caudal vertebrae implies a reduced ability to make tight turns. Examination of these vertebral traits in evolutionary context reveals a progressive sequence of increasing caudofemoral mass and tail rigidity among the Abelisauridae of South America.", "keyphrases": ["carnotaurus sastrei", "abelisaurid", "caudal vertebrae"]}
{"id": "10.1111/j.0031-0239.2004.00389.x", "title": "Revision of the Athyrisininae, Siluro\u2010devonian Brachiopods from China and Russia", "abstract": "Athyrisinine brachiopods from the Upper Silurian of Russia and the Lower\u2013Middle Devonian of China and north Vietnam include over 70 species belonging to Athyrisina and Parathyrisina; generic and subfamilial diagnoses are emended. Five genera are considered synonyms of Athyrisina and three of Parathyrisina. A neotype is selected and illustrated for Athyrisina squamosa, the type species of Athyrisina. Four nomina nova, Athyrisinaxui, Parathyrisina wani, P. minima, and P. cheni, are suggested as new substitute names for Athyrisina tumida Wang, in Xu et al. 1978 (primary homonymy), Athyrisinoides ganxiensis Wan, in Xu et al. 1978, Parathyrisina minor Zhang, in Zhang and Fu 1983, and Athyrisinoides tudilingensis Chen, 1979 (secondary homonyms) respectively. A new genus, Bruntosina, is described from the Emsian to Eifelian of the Qinling region. A new subfamily, Homeathyridinae, is erected within the Athyrididae with Homeathyris, Pseudohomeospira, and Squamathyris included, revised and their diagnoses emended. Homeathyris incisus sp. nov. is described from the Ludfordian of Novaya Zemlya. Ikella is revised and excluded from the athyrisinins. The origin and dispersal of the homeathyridins and the athyrisinins are discussed.", "keyphrases": ["athyrisininae", "brachiopod", "china"]}
{"id": "10.1029/94PA01455", "title": "Benthic phosphorus regeneration, net primary production, and ocean anoxia: A model of the coupled marine biogeochemical cycles of carbon and phosphorus", "abstract": "We examine the relationships between ocean ventilation, primary production, water column anoxia, and benthic regeneration of phosphorus using a mass balance model of the coupled marine biogeochemical cycles of carbon (C) and phosphorus (P). The elemental cycles are coupled via the Redfield C/P ratio of marine phytoplankton and the C/P ratio of organic matter preserved in marine sediments. The model assumes that on geologic timescales, net primary production in the oceans is limited by the upwelling of dissolved phosphorus to the photic zone. The model incorporates the dependence on bottom water oxygenation of the regeneration of nutrient phosphorus from particulate matter deposited at the water-sediment interface. Evidence from marine and lacustrine settings, modern and ancient, demonstrates that sedimentary burial of phosphorus associated with organic matter and ferric oxyhydroxides decreases when bottom water anoxia-dysoxia expands. Steady state simulations show that a reduction in the rate of thermohaline circulation, or a decrease of the oxygen content of downwelling water masses, intensifies water column anoxia-dysoxia and at the same time increases surface water productivity. The first effect reflects the declining supply of oxygen to the deeper parts of the ocean. The second effect is caused by the enhanced benthic regeneration of phosphorus from organic matter and ferric oxyhydroxides. Sedimentary burial of organic carbon and authigenic calcium phosphate mineral (francolite), on the other hand, is promoted by reduced ocean ventilation. According to the model, global-scale anoxia-dysoxia leads to a more efficient recycling of reactive phosphorus within the ocean system. Consequently, higher rates of primary production and organic carbon burial can be achieved, even when the continental supply of reactive phosphorus to the oceans remains unchanged.", "keyphrases": ["phosphorus", "regeneration", "net primary production", "ocean", "marine biogeochemical cycle"]}
{"id": "paleo.006601", "title": "Mesozoic salamanders and albanerpetontids of Middle Asia, Kazakhstan, and Siberia", "abstract": "Mesozoic terrestrial deposits containing diverse vertebrate assemblages are widely distributed in Siberia (central and eastern part of Russia), Middle Asia (Kyrgyzstan, Tajikistan, Turkmenistan and Uzbekistan), and Kazakhstan. Twelve formations of Middle Jurassic (Bathonian) to Late Cretaceous (Campanian) age in the region contain salamanders (six in Middle Asia, two in Siberia and four in Kazakhstan). In contrast to the situation in Euramerica, albanerpetontids are extremely rare in the Mesozoic of Asia, where their fossil record is limited to the Khodzhakul (Cenomanian) and Bissekty (Turonian) formations, both in Uzbekistan. Salamanders in Siberia are known from the Bathonian Itat Formation in the Krasnoyarsk Region (the stem salamander Urupia monstrosa and two undescribed taxa-a new stem salamander and a possible crown-group salamander) and from the Aptian-Albian Ilek Formation in Kemerovo Province and the Krasnoyarsk Region (the crown-group salamander Kiyatriton leshchinskiyi and Caudata indet.). In the Jurassic of Middle Asia, the stem salamanders Kokartus honorarius and Karauridae indet. are known from the Bathonian-Callovian Balabansai Formation in Kyrgyzstan. Younger records in Middle Asia are restricted to only two Late Cretaceous genera of crown-group salamanders: the possible cryptobranchoid Nesovtriton in the Bissekty Formation (Turonian) and the cryptobranchid Eoscapherpeton in the Khodzhakul, Dzharakuduk, Bissekty, and Aitym formations (collectively Cenomanian-Campanian) in Uzbekistan and the Yalovach Formation (Santonian) in Tajikistan. In Kazakhstan, salamanders are known from the Kimmeridgian Karabastau Formation (the stem salamander Karaurus sharovi), the Turonian Zhirkindek Formation (Caudata indet.), the Santonian-Campanian Bostobe Formation (the cryptobranchid Eoscapherpeton, the possible proteid \"Bishara backa\" and Caudata indet.) and the Campanian Darbasa Formation (the cryptobranchid Eoscapherpeton). Cenomanian-Campanian vertebrate assemblages in Middle Asia and Kazakhstan are characterised by dominance of the cryptobranchid Eoscapherpeton.", "keyphrases": ["salamander", "albanerpetontid", "kazakhstan"]}
{"id": "10.1111/j.1759-6831.2009.00007.x", "title": "Male spike strobiles with Gnetum affinity from the Early Cretaceous in western Liaoning, Northeast China", "abstract": "A fossil with Gnetum affinity was found in the Jianshangou Member (Barremian Age) of the Yixian Formation (Lower Cretaceous Epoch) of the Jehol Group in western Liaoning, northeastern China. The single fossil specimen is represented by both elongate\u2010cylindrical male spike strobiles which borne within a nodal bract of cauliflorous branch. The spike strobiles have apparent nodes, invisible internodes, and numerous verticillate involucral collars. The microsporangiate units within involucral collars are not seen. The male spike strobiles with verticillate involucral collars occur exclusively in Gnetum; hence, the fossil strobiles are attributed to a new taxon, Khitania columnispicata gen. & sp. nov., being closely related to Gnetum. The general isotopic dating suggests an age of Barremian, ca. 125\u2013122 million years (Myr) ago for the Jianshangou Member. The palaeoecological and palaeoclimatic inference based on the compositions of flora and fauna, and lithological characters of the fossil locality suggests that the fossil plants grew in a subtropical mesophytic forest and under a warmer climate. The remains of male spike strobiles are the first record of gnetalean macrofossil. It documents the evolution of the distinct gnetoid morphology and indicates a wider range of distribution of Gnetaceae in the Early Cretaceous than present day.", "keyphrases": ["gnetum affinity", "western liaoning", "gnetaceae", "male spike strobile"]}
{"id": "10.1111/1755-0998.12679", "title": "Ancient DNA analysis identifies marine mollusc shells as new metagenomic archives of the past", "abstract": "Marine mollusc shells enclose a wealth of information on coastal organisms and their environment. Their life history traits as well as (palaeo\u2010) environmental conditions, including temperature, food availability, salinity and pollution, can be traced through the analysis of their shell (micro\u2010) structure and biogeochemical composition. Adding to this list, the DNA entrapped in shell carbonate biominerals potentially offers a novel and complementary proxy both for reconstructing palaeoenvironments and tracking mollusc evolutionary trajectories. Here, we assess this potential by applying DNA extraction, high\u2010throughput shotgun DNA sequencing and metagenomic analyses to marine mollusc shells spanning the last ~7,000 years. We report successful DNA extraction from shells, including a variety of ancient specimens, and find that DNA recovery is highly dependent on their biomineral structure, carbonate layer preservation and disease state. We demonstrate positive taxonomic identification of mollusc species using a combination of mitochondrial DNA genomes, barcodes, genome\u2010scale data and metagenomic approaches. We also find shell biominerals to contain a diversity of microbial DNA from the marine environment. Finally, we reconstruct genomic sequences of organisms closely related to the Vibrio tapetis bacteria from Manila clam shells previously diagnosed with Brown Ring Disease. Our results reveal marine mollusc shells as novel genetic archives of the past, which opens new perspectives in ancient DNA research, with the potential to reconstruct the evolutionary history of molluscs, microbial communities and pathogens in the face of environmental changes. Other future applications include conservation of endangered mollusc species and aquaculture management.", "keyphrases": ["dna", "marine mollusc shell", "archive"]}
{"id": "10.1080/08912963.2017.1326111", "title": "A Serravallian (Middle Miocene) shark fauna from Southeastern Spain and its palaeoenvironment significance", "abstract": "Abstract The study of a new Serravallian (Middle Miocene) locality from the Southeastern Spain has yielded a shark assemblage characterized by microremains of at least seven taxa (Deania calcea, \u2020Isistius triangulus, \u2020Squaliolus cf. S. schaubi, \u2020Paraetmopterus sp., Pristiophorus sp., Scyliorhinus sp. and a cf. Squaliformes indet) of three different orders (Squaliformes, Pristiophoriformes and Carcharhiniformes). In addition, associated macroremains have also been found, including teeth of \u2020Cosmopolitodus hastalis, Isurus sp., Hemipristis serra, Odontaspis sp., Carcharhinus spp. and \u2020Otodus (Megaselachus) megalodon. The assemblage contains taxa with disparate environmental preferences including not only neritic and epipelagic sharks but also an important number of meso and bathypelagic representatives. The migration of deep water taxa to shallower waters through submarine canyons/coastal upwelling is proposed as the most plausible cause for explaining the origin of such assemblage. Interestingly, the composition of the deep-water taxa here reported contrast with the chondrichthyans assemblages from the Pliocene and extant Mediterranean communities. This entails a complex biogeographic history, where the Messinian salinity crisis strongly affected the posterior evolution of the Mediterranean ecosystems but some other factors, such us the existence of anoxic events during the Quaternary, could have also played an important role.", "keyphrases": ["middle miocene", "southeastern spain", "extensive fossil record"]}
{"id": "10.1002/ajb2.1772", "title": "Quantifying the effect of shade on cuticle morphology and carbon isotopes of sycamores: present and past", "abstract": "Abstract Premise Reconstructing the light environment and architecture of the plant canopy from the fossil record requires the use of proxies, such as those derived from cell wall undulation, cell size, and carbon isotopes. All approaches assume that plant taxa will respond predictably to changes in light environments. However, most species\u2010level studies looking at cell wall undulation only consider \u201csun\u201d or \u201cshade\u201d leaves; therefore, we need a fully quantitative taxon\u2010specific method. Methods We quantified the response of cell wall undulation, cell size, and carbon isotopes of Platanus occidentalis using two experimental setups: (1) two growth chambers at low and high light and (2) a series of outdoor growth experiments using green and black shade cloth at different densities. We then developed and applied a proxy for daily light integral (DLI) to fossil Platanites leaves from two early Paleocene floras from the San Juan Basin in New Mexico. Results All traits responded to light environment. Cell wall undulation was the most useful trait for reconstructing DLI in the geological record. Median reconstructed DLI from early Paleocene leaves was ~44\u2009mol\u2009m\u22122\u2009d\u22121, with values from 28 to 54\u2009mol\u2009m\u22122\u2009d\u22121. Conclusions Cell wall undulation of P. occidentalis is a robust, quantifiable measurement of light environment that can be used to reconstruct the paleo\u2010light environment from fossil leaves. The distribution of high DLI values from fossil leaves may provide information on canopy architecture; indicating that either (1) most of the canopy mass is within the upper portion of the crown or (2) leaves exposed to more sunlight are preferentially preserved.", "keyphrases": ["shade", "carbon isotope", "measurement"]}
{"id": "paleo.004929", "title": "Climate change, not human population growth, correlates with Late Quaternary megafauna declines in North America", "abstract": "The disappearance of many North American megafauna at the end of the Pleistocene is a contentious topic. While the proposed causes for megafaunal extinction are varied, most researchers fall into three broad camps emphasizing human overhunting, climate change, or some combination of the two. Understanding the cause of megafaunal extinctions requires the analysis of through-time relationships between climate change and megafauna and human population dynamics. To do so, many researchers have used summed probability density functions (SPDFs) as a proxy for through-time fluctuations in human and megafauna population sizes. SPDFs, however, conflate process variation with the chronological uncertainty inherent in radiocarbon dates. Recently, a new Bayesian regression technique was developed that overcomes this problem-Radiocarbon-dated Event-Count (REC) Modelling.\nHere we employ REC models to test whether declines in North American megafauna species could be best explained by climate changes, increases in human population densities, or both, using the largest available database of megafauna and human radiocarbon dates. Our results suggest that there is currently no evidence for a persistent through-time relationship between human and megafauna population levels in North America. There is, however, evidence that decreases in global temperature correlated with megafauna population declines.", "keyphrases": ["decline", "north america", "cause", "megafaunal extinction", "climate change"]}
{"id": "10.1017/S0263593300010488", "title": "Trilobite abnormalities", "abstract": "ABSTRACT There is abundant evidence of injury, teratology and pathological conditions in trilobites although it is commonly difficult to distinguish between their morphological results. Many injuries were probably sustained during moulting, with spines, bilamellar fringes and narrow gaps between dorsal exoskeleton and doublure being most vulnerable. Some injuries were the result of predaceous attack and provide important clues to the trophic structure of Palaeozoic communities. Many injuries show evidence of repair. Some supposedly teratological conditions, most notably the number of paradoxidid thoracic segments, are so common that they must be considered part of normal variation. Others represent genetic mutation or ontogenetic malfunction, the latter possibly externally induced. Undoubted pathological conditions are restricted to swellings and borings presumably caused by parasitic infestation. Abnormalities affecting lateral areas are more common than those involving the rachis and glabella and this probably reflects both greater mortality when the axial region is involved, and greater vulnerability of peripheral regions to predaceous and moulting damage. The first explanation also accounts for the rarity of cephalic abnormalities compared to those of the pygidium.", "keyphrases": ["abnormality", "injury", "teratology", "trilobite"]}
{"id": "paleo.006602", "title": "The locomotory apparatus and paraxial swimming in fossil and living marine reptiles: comparing Nothosauroidea, Plesiosauria, and Chelonioidea", "abstract": "The terrestrial origins of the diapsid Sauropterygia and Testudines are uncertain, with the latter being highly controversially discussed to this day. For only 15 Ma, Nothosauroidea lived in shallow-marine seas of the Triassic. Contrastingly, the pelagic Plesiosauria evolved in the Late Triassic, dispersed globally, and inhabited the oceans of the Jurassic and Cretaceous for approximately 135 Ma. Since the Cretaceous (~ 100 Ma), Chelonioidea, the modern sea turtles, have populated the oceans. All three groups evolved aquatic paraxial locomotion. Nothosaurs swam with their foreflippers, supported by the swimming tail. Plesiosaurs are the only tetrapods to have ever evolved four hydrofoil-like flippers. The plesiosaur flipper beat cycle has been debated for nearly two centuries. The different proposed locomotory styles (rowing, rowing-flight, underwater flight) are discussed in this review. A fourth gait that is employed by Carettochelys insculpta, which combines rowing and flying, is introduced. The osteology of the locomotory apparatus of nothosaurs and plesiosaurs is reviewed and compared to that of extant underwater-flying Chelonioidea. In conclusion, underwater flight remains the favoured locomotory style for plesiosaurs. Also, the review reveals that nothosaur locomotion has largely remained unstudied. Further, our understanding of joint morphologies and mobilities of the foreflipper in nothosaurs, plesiosaurs, and even recent sea turtles, and of the hindflipper in plesiosaurs, is very limited. It is crucial to the discussion of locomotion, to find out, if certain limb cycles were even possible, as evidence seems to point to the improbability of a rowing motion because of limited humerus and femur long axis rotation in plesiosaurs.\nNothosauroidea \u2022 Plesiosauria \u2022 Chelonioidea \u2022 Mode of locomotion \u2022 Rowing \u2022 Underwater flight\nEvolution of Nothosauroidea and Plesiosauria (Eosauropterygia) and Chelonioidea\nSauropterygia were amongst the first fossil reptiles subjected to paleontological research (de la Beche and Conybeare 1821; Owen 1840; von Meyer 1847-1855). Since then, researchers have studied not only their morphology and phylogeny, but also different aspects of their biology (", "keyphrases": ["locomotory apparatus", "plesiosauria", "chelonioidea", "flipper"]}
{"id": "paleo.001903", "title": "Siphonal zone structure in the cuttlebone of Sepia officinalis", "abstract": "The evolutionary process through which the siphonal zone of the cuttlebone of Sepia replaced the tubular siphuncle seen in other shelled cephalopods is poorly understood. Recently, porous connecting stripes, interpreted as homologous to connecting rings of tubular siphuncles, were revealed in Sepia (Acanthosepion) cf. savignyi (Geobios, 45:13-17, 2012). New data on the siphonal zone structure are herein demonstrated through SEM testing of 16 beach-collected cuttlebones of Sepia officinalis from Vale do Lobo, southern Portugal. In examined cuttlebones, the organic connecting stripes are mineralized along their peripheries where they are attached to septa by inorganic-organic porous contacting ridges. The contacting ridges consist of globular crystalline units within an organic matrix; each globule is a stack of rounded alternating organic and mineralized microlaminas parallel to the septal surface; mineralized microlaminas contain carbonate microgranules. Porous connecting stripes together with the contacting ridges may serve as transport routes for the cameral liquid used in buoyancy regulation. The contacting ridges appear to reinforce contacts between the connecting stripes and septa, and may strengthen shell resistance to changing environments. Lamella-fibrillar nacre in septa is demonstrated in Sepia for the first time. Comparison of Sepia and Spirula reveals the common character of their phragmocones, the slit-like shape of the permeable zones between chambers and the siphuncle. Narrowing of the permeable zones may provide shell resistance to high hydrostatic pressure; however, the essentially dissimilar relative length of the permeable zones may results in different capabilities of two genera for buoyancy regulation. In Sepia, long narrow porous inorganic-organic permeable connecting stripes and contacting ridges may allow for rapid buoyancy regulation which would lead to environmental plasticity and higher species diversity.", "keyphrases": ["cuttlebone", "sepia", "siphonal zone structure"]}
{"id": "10.1002/2015PA002810", "title": "Optimized coral reconstructions of the Indian Ocean Dipole: An assessment of location and length considerations", "abstract": "The Indian Ocean Dipole (IOD; or Indian Ocean Zonal Mode) is a coupled ocean-atmosphere climate oscillation that has profound impacts on rainfall distribution across the Indian Ocean region. Instrumental records provide a reliable representation of IOD behavior since 1958, while coral reconstructions currently extend the IOD history back to 1846. Large fluctuations in the number and intensity of positive IOD events over time are evident in these records, but it is unclear to what extent this represents multidecadal modulation of the IOD or an anthropogenically forced change in IOD behavior. In this study we explore the suitability of coral records from single-site locations in the equatorial Indian Ocean for capturing information about the occurrence and magnitude of positive IOD (pIOD) events. We find that the optimum location for coral reconstructions of the IOD occurs in the southeastern equatorial Indian Ocean, along the coast of Java and Sumatra between ~3 and 7\u00b0S. Here the strong ocean cooling and atmospheric drying during pIOD events are unambiguously recorded in coral oxygen isotope records, which capture up to 50% of IOD variance. Unforced experiments with coupled climate models suggest that potential biases in coral estimates of pIOD frequency are skewed toward overestimating pIOD recurrence intervals and become larger with shorter reconstruction windows and longer pIOD recurrence times. Model output also supports the assumption of stationarity in sea surface temperature relationships in the optimum IOD location that is necessary for paleoclimate reconstructions. This study provides a targeted framework for the future generation of paleoclimate records, including optimized coral reconstructions of past IOD variability.", "keyphrases": ["coral reconstruction", "indian ocean dipole", "paleoclimate reconstruction", "iod variability"]}
{"id": "10.1002/ajpa.22086", "title": "Dental microwear and stable isotopes inform the paleoecology of extinct hominins.", "abstract": "Determining the diet of an extinct species is paramount in any attempt to reconstruct its paleoecology. Because the distribution and mechanical properties of food items may impact postcranial, cranial, mandibular, and dental morphologies related to their procurement, ingestion, and mastication, these anatomical attributes have been studied intensively. However, while mechanical environments influence skeletal and dental features, it is not clear to what extent they dictate particular morphologies. Although biomechanical explanations have been widely applied to extinct hominins in attempts to retrodict dietary proclivities, morphology may say as much about what they were capable of eating, and perhaps more about phylogenetic history, than about the nature of the diet. Anatomical attributes may establish boundary limits, but direct evidence left by the foods that were actually (rather than hypothetically) consumed is required to reconstruct diet. Dental microwear and the stable light isotope chemistry of tooth enamel provide such evidence, and are especially powerful when used in tandem. We review the foundations for microwear and biogeochemistry in diet reconstruction, and discuss this evidence for six early hominin species (Ardipithecus ramidus, Australopithecus anamensis, Au. afarensis, Au. africanus, Paranthropus robustus, and P. boisei). The dietary signals derived from microwear and isotope chemistry are sometimes at odds with inferences from biomechanical approaches, a potentially disquieting conundrum that is particularly evident for several species.", "keyphrases": ["paleoecology", "extinct hominin", "paranthropus robustus", "several specie", "dental microwear"]}
{"id": "paleo.008274", "title": "Ancient mitochondrial genomes from Chinese cave hyenas provide insights into the evolutionary history of the genus Crocuta", "abstract": "Cave hyenas (genus Crocuta) are extinct bone-cracking carnivores from the family Hyaenidae and are generally split into two taxa that correspond to a European/Eurasian and an (East) Asian lineage. They are close relatives of the extant African spotted hyenas, the only extant member of the genus Crocuta. Cave hyenas inhabited a wide range across Eurasia during the Pleistocene, but became extinct at the end of the Late Pleistocene. Using genetic and genomic datasets, previous studies have proposed different scenarios about the evolutionary history of Crocuta. However, causes of the extinction of cave hyenas are widely speculative and samples from China are severely understudied. In this study, we assembled near-complete mitochondrial genomes from two cave hyenas from northeastern China dating to 20 240 and 20 253 calBP, representing the youngest directly dated fossils of Crocuta in Asia. Phylogenetic analyses suggest a monophyletic clade of these two samples within a deeply diverging mitochondrial haplogroup of Crocuta. Bayesian analyses suggest that the split of this Asian cave hyena mitochondrial lineage from their European and African relatives occurred approximately 1.85 Ma (95% CI 1.62\u20132.09 Ma), which is broadly concordant with the earliest Eurasian Crocuta fossil dating to approximately 2 Ma. Comparisons of mean genetic distance indicate that cave hyenas harboured higher genetic diversity than extant spotted hyenas, brown hyenas and aardwolves, but this is probably at least partially due to the fact that their mitochondrial lineages do not represent a monophyletic group, although this is also true for extant spotted hyenas. Moreover, the joint female effective population size of Crocuta (both cave hyenas and extant spotted hyenas) has sustained two declines during the Late Pleistocene. Combining this mitochondrial phylogeny, previous nuclear findings and fossil records, we discuss the possible relationship of fossil Crocuta in China and the extinction of cave hyenas.", "keyphrases": ["mitochondrial genome", "hyena", "evolutionary history", "genus crocuta", "late pleistocene"]}
{"id": "paleo.012396", "title": "Comparative Taphonomy, Taphofacies, and Bonebeds of the Mio-Pliocene Purisima Formation, Central California: Strong Physical Control on Marine Vertebrate Preservation in Shallow Marine Settings", "abstract": "Background Taphonomic study of marine vertebrate remains has traditionally focused on single skeletons, lagerst\u00e4tten, or bonebed genesis with few attempts to document environmental gradients in preservation. As such, establishment of a concrete taphonomic model for shallow marine vertebrate assemblages is lacking. The Neogene Purisima Formation of Northern California, a richly fossiliferous unit recording nearshore to offshore depositional settings, offers a unique opportunity to examine preservational trends across these settings. Methodology/Principal Findings Lithofacies analysis was conducted to place vertebrate fossils within a hydrodynamic and depositional environmental context. Taphonomic data including abrasion, fragmentation, phosphatization, articulation, polish, and biogenic bone modification were recorded for over 1000 vertebrate fossils of sharks, bony fish, birds, pinnipeds, odontocetes, mysticetes, sirenians, and land mammals. These data were used to compare both preservation of multiple taxa within a single lithofacies and preservation of individual taxa across lithofacies to document environmental gradients in preservation. Differential preservation between taxa indicates strong preservational bias within the Purisima Formation. Varying levels of abrasion, fragmentation, phosphatization, and articulation are strongly correlative with physical processes of sediment transport and sedimentation rate. Preservational characteristics were used to delineate four taphofacies corresponding to inner, middle, and outer shelf settings, and bonebeds. Application of sequence stratigraphic methods shows that bonebeds mark major stratigraphic discontinuities, while packages of rock between discontinuities consistently exhibit onshore-offshore changes in taphofacies. Conclusions/Significance Changes in vertebrate preservation and bonebed character between lithofacies closely correspond to onshore-offshore changes in depositional setting, indicating that the dominant control of preservation is exerted by physical processes. The strong physical control on marine vertebrate preservation and preservational bias within the Purisima Formation has implications for paleoecologic and paleobiologic studies of marine vertebrates. Evidence of preservational bias among marine vertebrates suggests that careful consideration of taphonomic overprint must be undertaken before meaningful paleoecologic interpretations of shallow marine vertebrates is attempted.", "keyphrases": ["bonebed", "marine vertebrate preservation", "shark"]}
{"id": "10.1029/1999pa000487", "title": "Correlation of Late Miocene to Early Pliocene sequences between the Mediterranean and North Atlantic", "abstract": "Ocean Drilling Program (ODP) Site 982 in the North Atlantic contains a complete latest Miocene to early Pliocene section that was tuned to the astronomical timescale by correlating the record of gamma ray attenuation (GRA) bulk density to summer insolation at 65\u00b0N and the benthic \u03b418O signal to orbital obliquity for the interval from 4.6 to 7.5 Ma. The astronomical tuning of the Site 982 record permits a direct bed-to-bed correlation to the cyclostratigraphy of Messinian sections in the Mediterranean [Krijgsman et al., 1999a, 2001]. The benthic \u03b418O signal at Site 982 records a latest Miocene glacial period that lasted from \u223c6.26 to 5.50 Ma and consisted of 18 glacial-to-interglacial oscillations that were controlled by the 41-kyr cycle of obliquity. Although the intensification of glaciation at 6.26 Ma may have contributed to the restriction of the Mediterranean, it preceded the depositional onset of the lower evaporite unit at 5.96 Ma by some 300 kyr. The transition from Stage TG12 to TG11 at 5.5 Ma marks the end of the latest Miocene glacial period and precedes the Miocene/Pliocene boundary by 170 kyr. Although benthic \u03b418O values are relatively low and \u03b418O of bulk carbonate reaches a minimum at the Miocene/Pliocene boundary at 5.33 Ma, there is no single \u201cevent\u201d that would indicate deglaciation and sea level rise as the cause of the reflooding of the Mediterranean. We conclude that glacioeustatic changes alone were not responsible for either the start or end of evaporite deposition during the Messinian, suggesting that tectonic or local climate changes in the Mediterranean region were the dominant cause(s).", "keyphrases": ["late miocene", "mediterranean", "north atlantic", "glaciation"]}
{"id": "10.7717/peerj.1331", "title": "An investigation of the genus Mesacanthus (Chordata: Acanthodii) from the Orcadian Basin and Midland Valley areas of Northern and Central Scotland using traditional morphometrics", "abstract": "Mesacanthus is a common and speciose genus of acanthodian fish from Lower Old Red Sandstone and Middle Old Red Sandstone assemblages (representing the Lower Devonian and Middle Devonian respectively) and is well represented in many palaeoichthyology collections in the UK. Based upon descriptions given during the 19th century, specimens of the genus Mesacanthus from the Orcadian Basin and Midland Valley areas of Northern and Central Scotland have historically been referred to a number of different species; of these, the most frequently discussed in the literature are M. mitchelli, M. peachi and M. pusillus. In order to test the validity of these three species, traditional morphometric analyses were carried out on over 100 specimens of Mesacanthus, from both the Lower Devonian and the Middle Devonian, that cover the full range of known localities for these taxa in Northern and Central Scotland. Based upon morphological and morphometric comparisons, this investigation has found that at least two species of Mesacanthus are valid (M. mitchelli and M. pusillus) as specimens from the Lower Devonian and Middle Devonian have been shown to differ significantly in a number of important ways. However, no evidence has been found for the validity of the second and distinct Middle Devonian species, M. peachi.", "keyphrases": ["genus mesacanthus", "orcadian basin", "central scotland", "middle devonian specie"]}
{"id": "10.1111/pala.12226", "title": "A new family of Cambrian rhynchonelliformean brachiopods (Order Naukatida) with an aberrant coral\u2010like morphology", "abstract": "Tomteluva perturbata gen. et sp. nov. and Nasakia thulensis gen. et sp. nov., two new rhynchonelliformean brachiopod taxa, are described from carbonate beds from the lower middle Cambrian (Series 3, Stage 5) basinal Stephen Formation, Canada, and the upper lower Cambrian (Series 2, Stage 4) Henson Gletscher Formation, North Greenland, respectively. The two taxa are characterized by an unusual coral\u2010like morphology typified by a high conical ventral valve with an anteriorly curved umbo and a tube\u2010like structure inside the ventral valve, interpreted as pedicle tube. Both resemble the problematic late middle Cambrian (Drumian) species Anomalocalyx cawoodi Brock from Australia, whose systematic affiliation is controversial. Together, the three genera are interpreted as representatives of a new family of rhynchonelliformean brachiopods, the Tomteluvidae fam. nov., which is interpreted as an aberrant or derived taxon within the Order Naukatida. Convergence between the Tomteluvidae and the coralla of small solitary Cambrian coralimorphs, as well as the late Palaeozoic reef\u2010building richthofenioid brachiopods, might indicate adaptation to a similar life habits and environments. However, their small size (length 4 mm), well\u2010developed pedicle and perfect morphological symmetry make it more likely that tomteluvids lived attached to frondose algae or sponges, above the seafloor, in a similar fashion to the acrotretoid brachiopods with which they show a high degree of morphological convergence. Morphological features of the pedicle tube of N. thulensis suggest that the tomteluvid pedicle is homologous to that in modern rhynchonelliformean brachiopods. This is the first evidence of the pedicle type within the Naukatida and represents the oldest confirmation of a rhynchonellate pedicle.", "keyphrases": ["new family", "rhynchonelliformean brachiopod", "order naukatida"]}
{"id": "paleo.006427", "title": "Patterning of a compound eye on an extinct dipteran wing", "abstract": "We have discovered unexpected similarities between a novel and characteristic wing organ in an extinct biting midge from Baltic amber, Eohelea petrunkevitchi, and the surface of a dipteran's compound eye. Scanning electron microscope images now reveal vestigial mechanoreceptors between the facets of the organ. We interpret Eohelea's wing organ as the blending of these two developmental systems: the formation and patterning of the cuticle in the eye and of the wing. Typically, only females in the genus carry this distinctive, highly organized structure. Two species were studied (E. petrunkevitchi and E. sinuosa), and the structure differs in form between them. We examine Eohelea's wing structures for modes of fabrication, material properties and biological functions, and the effective ecological environment in which these midges lived. We argue that the current view of the wing organ's function in stridulation has been misconstrued since it was described half a century ago.", "keyphrases": ["compound eye", "wing", "female"]}
{"id": "paleo.006036", "title": "Ordovician ostracods from east central Iran", "abstract": "Ordovician ostracods are described for the first time from Iran, enhancing the record of this group from the Lower Palaeozoic of the Middle East. The ostracods occur in the Shirgesht Formation, in the east central part of the country, and comprise Ogmoopsis achaemenid sp. nov., Cerninella aryana sp. nov., Ordovizona amyitisae sp. nov., cf. Aechmina? ventadorni, Vogdesella sp., and podocope taxa tentatively identified as species of Longiscula, Pullvillites, and Rectella. These taxa were hitherto unknown from this region. The ostracod-bearing interval is associated with trilobites (Neseuretinus) and brachiopods (Nicolella) that suggest a late Middle Ordovician age. Although the ostracod fauna is small, it demonstrates biogeographical links at genus-level, and possibly at species-level, with the fauna of the late Middle Ordovician Travesout Formation of western France, which also lay in a peri-Gondwanan palaeogeographical setting. It also suggests the potential use of some ostracods as stratigraphical tools for correlating Ordovician rock successions between Europe and the Middle East.", "keyphrases": ["shirgesht formation", "ostracod fauna", "ordovician ostracod"]}
{"id": "10.18476/pale.v13.a3", "title": "New trilophosaurid species demonstrates a decline in allokotosaur diversity across the Adamanian-Revueltian boundary in the Late Triassic of western North America", "abstract": "Abstract Allokotosauria, including Trilophosauridae and Azendohsauridae, is an extinct archosauromorph group that reached a near-Pangean distribution in the Middle Triassic to Late Triassic and evolved a broad range of cranial and dental morphologies. Within the Chinle Formation of western North America, allokotosaurs span the Norian-aged Blue Mesa Member (Adamanian estimated holochronozone) and Sonsela Member (Adamanian and Revueltian estimated holochronozone). The Adamanian-Revueltian faunal assemblage transition is hypothesized to represent extinction and faunal turnover in large-bodied archosauromorphs, but poor sampling of known localities has obscured any similar patterns in tetrapods <1 m long. Trilophosaurids are the most common smaller-bodied herbivorous taxa found in Adamanian microvertebrate sites, with four species previously reported (Trilophosaurus buettneri, T. jacobsi, T. dornorum, and Spinosuchus caseanus). The presence of three new allokotosaur taxa in Adamanian microvertebrate sites, including a new species of trilophosaurid described here (Trilophosaurus phasmalophos sp. nov.) demonstrates the high diversity of this group in the Adamanian. Trilophosaurus phasmalophos occurs in microvertebrate-bearing horizons in the Jim Camp Wash beds of the Sonsela Member, making it the first unambiguous trilophosaurid reported from the Revueltian estimated holochronozone. Unlike in other trilophosaurids, the teeth are bicuspid, but the cusp and cingulum structure and complexity are similar to those of Trilophosaurus dornorum and T. jacobsi. The Adamanian-Revueltian boundary marks a reduction in allokotosaur diversity from five Adamanian taxa to one Revueltian taxon. This pattern of faunal turnover and extinction is similar to those of other large-bodied archosauromorph clades across the Adamanian-Revueltian boundary in the American Southwest. Systematic sampling of microvertebrate bonebeds at stratigraphic intervals across this boundary demonstrates that this turnover in allokotosaurs may reveal similar patterns in other groups that have been missed because of collecting biases towards larger-bodied vertebrate fossils.", "keyphrases": ["allokotosaur diversity", "late triassic", "western north america", "cusp"]}
{"id": "10.2478/s13386-011-0023-8", "title": "Upper Cretaceous volcanoclastic deposits from the Ha\u0163eg basin, south Carpathians (Romania): K-Ar ages and intrabasinal correlation", "abstract": "In order to constrain the age of the Upper Cretaceous continental Densu\u015f-Ciula Formation from the Ha\u0163eg basin, South Carpathians, and correlate it with the other continental unit that occurs in the region, the S\u00e2npetru Formation, we separated and dated by the K-Ar method biotites and amphiboles from volcanoclastic deposits. The mineral phases analysed are from two tuff layers and volcanic bombs cropping out near Rachitova village. Two tuff layers from the Densu\u015f-Ciula Formation give early Maastrichtian ages of 69.8\u00b11.3 and 71.3\u00b11.6 Ma, respectively. The ages determined for the tuff layers constrain the age of deposition for the Densu\u015f-Ciula Formation and enable further correlations with the available palaeomagnetic data from the deposits occurring along the Sibi\u015fel Valley that belong to the S\u00e2npetru Formation. The volcanic bombs collected near to R\u0103chitova village are andesites and dacites. The age determined by K-Ar method on hornblende separated from a volcanic bomb is 82.7\u00b11.5 Ma, which is older than the underlying Campanian marine deposits in turbidite facies. This suggests that the volcanic bombs were re-deposited during the early Maastrichtian. Thus, the volcanics found at R\u0103chitova have at least two origins: one type is related to an explosive synsedimentary volcanic activity, and the other type is represented by older andesitic/dacitic bombs, which most probably originate from a volcanic centre situated in the Ha\u0163eg region.", "keyphrases": ["volcanoclastic deposit", "ha\u0163eg basin", "south carpathians", "maastrichtian age"]}
{"id": "10.1111/j.1096-0031.2003.tb00387.x", "title": "The deep divergences of neornithine birds: a phylogenetic analysis of morphological characters", "abstract": "Consensus is elusive regarding the phylogenetic relationships among neornithine (crown clade) birds. The ongoing debate over their deep divergences is despite recent increases in available molecular sequence data and the publication of several larger morphological data sets. In the present study, the phylogenetic relationships among 43 neornithine higher taxa are addressed using a data set of 148 osteological and soft tissue characters, which is one of the largest to date. The Mesozoic non\u2010neornithine birds Apsaravis, Hesperornis, and Ichthyornis are used as outgroup taxa for this analysis. Thus, for the first time, a broad array of morphological characters (including both cranial and postcranial characters) are analyzed for an ingroup densely sampling Neornithes, with crown clade outgroups used to polarize these characters. The strict consensus cladogram of two most parsimonious trees resultant from 1000 replicate heuristic searches (random stepwise addition, tree\u2010bisection\u2010reconnection) recovered several previously identified clades; the at\u2010one\u2010time contentious clades Galloanseres (waterfowl, fowl, and allies) and Palaeognathae were supported. Most notably, our analysis recovered monophyly of Neoaves, i.e., all neognathous birds to the exclusion of the Galloanseres, although this clade was weakly supported. The recently proposed sister taxon relationship between Steatornithidae (oilbird) and Trogonidae (trogons) was recovered. The traditional taxon \u201cFalconiformes\u201d (Cathartidae, Sagittariidae, Accipitridae, and Falconidae) was not found to be monophyletic, as Strigiformes (owls) are placed as the sister taxon of (Falconidae + Accipitridae). Monophyly of the traditional \u201cGruiformes\u201d (cranes and allies) and \u201dCiconiiformes\u201d (storks and allies) was also not recovered. The primary analysis resulted in support for a sister group relationship between Gaviidae (loons) and Podicipedidae (grebes)\u2014foot\u2010propelled diving birds that share many features of the pelvis and hind limb. Exclusion of Gaviidae and reanalysis of the data set, however, recovered the sister group relationship between Phoenicopteridae (flamingos) and grebes recently proposed from molecular sequence data.", "keyphrases": ["deep divergence", "phylogenetic analysis", "morphological character", "present study", "mayr"]}
{"id": "paleo.012510", "title": "Chitinase genes (CHIAs) provide genomic footprints of a post-Cretaceous dietary radiation in placental mammals", "abstract": "Mammal genomes retain remnants of chitinase genes, pointing to dietary shifts in the wake of the K/Pg mass extinction. The end-Cretaceous extinction led to a massive faunal turnover, with placental mammals radiating in the wake of nonavian dinosaurs. Fossils indicate that Cretaceous stem placentals were generally insectivorous, whereas their earliest Cenozoic descendants occupied a variety of dietary niches. It is hypothesized that this dietary radiation resulted from the opening of niche space, following the extinction of dinosaurian carnivores and herbivores. We provide the first genomic evidence for the occurrence and timing of this dietary radiation in placental mammals. By comparing the genomes of 107 placental mammals, we robustly infer that chitinase genes (CHIAs), encoding enzymes capable of digesting insect exoskeletal chitin, were present as five functional copies in the ancestor of all placental mammals, and the number of functional CHIAs in the genomes of extant species positively correlates with the percentage of invertebrates in their diets. The diverse repertoire of CHIAs in early placental mammals corroborates fossil evidence of insectivory in Cretaceous eutherians, with descendant lineages repeatedly losing CHIAs beginning at the Cretaceous/Paleogene (K/Pg) boundary as they radiated into noninsectivorous niches. Furthermore, the timing of gene loss suggests that interordinal diversification of placental mammals in the Cretaceous predates the dietary radiation in the early Cenozoic, helping to reconcile a long-standing debate between molecular timetrees and the fossil record. Our results demonstrate that placental mammal genomes, including humans, retain a molecular record of the post-K/Pg placental adaptive radiation in the form of numerous chitinase pseudogenes.", "keyphrases": ["chias", "placental mammal", "enzyme", "early cenozoic", "chitinase gene"]}
{"id": "paleo.007089", "title": "Mode of life and hydrostatic stability of orthoconic ectocochleate cephalopods: hydrodynamic analyses of restoring moments from 3D-printed, neutrally buoyant models", "abstract": "Theoretical 3D models were digitally reconstructed from a phragmocone section of Baculites compressus in order to investigate the hydrostatic properties of the orthoconic morphotype. These virtual models all had the capacity for neutral buoyancy (or nearly so) and were highly stable with vertical syn vivo orientations. Body chamber lengths exceeding approximately 40% of the shell length cause buoyancy to become negative with the given modeled proportions. The distribution of cameral liquid within the phragmocone does not change orientation and only slightly influences hydrostatic stability. The mass of cameral liquid required to completely reduce stability, permitting a non-vertical static orientation, would cause the living cephalopod to become negatively buoyant. A concave dorsum does not significantly change the mass distribution and results in a 5\u00b0 dorsal rotation of the aperture from vertical. The restoring moments acting to return neutrally buoyant objects to their equilibrium position were investigated using 3D-printed models of Nautilus pompilius and Baculites compressus with theoretically equal masses and hydrostatic stabilities to their virtual counterparts. The N. pompilius behaved as an underdamped harmonic oscillator during restoration due to its low hydrostatic stability and drag relative to the B. compressus model. In contrast, the B. compressus model more quickly returns to its equilibrium position without oscillating (overdamped system). The thrust required to overcome such a large restoring moment was explored using several extant cephalopod analogues. Significant angles of displacement were only achieved with coleoid-like thrusts, which were unrealistically high despite the probable similarities in their locomotor design. These maximum bursts of thrust may have been too energetically expensive and would preclude an unusual form of locomotion in a non-vertical orientation. These results suggest baculitids and other orthocones with similar hydrostatic stabilities probably lived a nektic to quasiplanktic mode of life with a primarily vertical orientation and mobility.", "keyphrases": ["hydrostatic stability", "moment", "buoyancy"]}
{"id": "paleo.006290", "title": "A new Early Triassic gastropod genus and the recovery of gastropods from the Permian/Triassic extinction", "abstract": "The common Early Triassic (Olenekian) gastropod Turbo rectecostatus from the upper Werfen Formation of the Alps is placed in the new genus Werfenella. Elimination of the wrong or outdated generic assignments of Late Palaeozoic and Early Mesozoic gastropods to archetypical genera such as Turbo, Trochus, or Natica (all with Recent type species) represents an important step toward understanding the evolutionary history of the gastropods across the Permian/Triassic mass-extinction event. The first appearance of Werfenella in the Olenekian, as well as the origination of other groups of gastropods, suggests an early turnover in the aftermath of the end-Permian mass extinction event. The relatively large size of Werfenella (up to 35 mm) sheds doubt on assertions that all Early Triassic gastropods are microgastropods (Lilliput effect). The new genus is placed in the caenogastropod family Purpurinidae and represents its earliest occurrence. However, a placement of Werfenella in the Archaeogastropoda (Vetigastropoda) is also possible because it resembles the paraturbinid genus Chartronella. The characteristic Werfenella rectecostata-Natiria costata gastropod association from the Werfen Formation is not found in the approximately contemporaneous Sinbad Limestone of the Moenkopi Formation (Utah, USA) nor elsewhere outside Europe. This suggests that the similarities between Olenekian gastropod faunas from the Tethys and western North America are more limited than previously thought.", "keyphrases": ["early triassic", "gastropod", "permian", "lilliput effect"]}
{"id": "paleo.004801", "title": "Carnian (Late Triassic) ostracods from the Sorgun Ophiolitic M\u00e9lange (Southern Turkey): Taxonomy, palaeoenvironment, and evidence of predation", "abstract": "The Mersin Ophiolitic Complex is situated in southern Turkey and contains the relics of the Palaeotethys and Neotethys Oceans and of the Huglu-Pindos basin. The succession exposed at the Tavus\u00e7ayiri Block has been intensely studied but ostracods are still poorly documented. This paper illustrates and discusses the ostracods extracted from a radiolarian-rich limestone of the lower Tuvalian Spongotortilispinus moixi radiolarian Zone (Carnian, Late Triassic) intercalated with thick green tuffs. The moderately abundant assemblage (40 specimens) is composed of 29 species, 16 genera of seven families, including one new species: Bairdiacypris sorgunensis Forel sp. nov. This assemblage points to a moderately shallow subtidal environment submitted to short-lived environmental instabilities. In regards to the slightly older ostracods recently reported from the Tavus\u00e7ayiri Block, the present record illustrates an upwards shallowing trend for the Carnian succession. All the taxa found are of typical MesozoicCenozoic affinity, in contrast to the slightly older assemblage from the Julian of the Tavus\u00e7ayiri Block (Kilek section), which also include Palaeozoic taxa. This different pattern could relate either to the disappearance of Palaeozoic taxa during the intervening interval or to their survival only in relatively deeper waters. Finally, we also report the oldest known record of a boring trace on the surface of an ostracod valve, probably of predatory origin. It represents the first evidence of predation on micro-benthos in the Triassic and is in line with several recent studies attesting the establishment of boring predation in the Late Triassic. Marie-B\u00e9atrice Forel. MNHN-CNRS-SU, Mus\u00e9um national d\u2019Histoire naturelle, 8 rue Buffon (CP38), 75005 Paris, France. marie-beatrice.forel@mnhn.fr P\u00e9ter Ozsv\u00e1rt. MTA-MTM-ELTE, Research Group for Paleontology, P.O. Box 137, H 1431 Budapest, Hungary. ozsvart.peter@nhmus.hu Patrice Moix. Rue de la Combe 55, 1969 Eison, Switzerland. patricemoix@gmail.com http://zoobank.org/BDBCC335-201C-4197-949A-81747E64B3B8 Forel, Marie-B\u00e9atrice, Ozsv\u00e1rt, P\u00e9ter, and Moix, Patrice. 2018. Carnian (Late Triassic) ostracods from the Sorgun Ophiolitic M\u00e9lange (Southern Turkey): Taxonomy, palaeoenvironment, and evidence of predation. Palaeontologia Electronica 21.2.26A 1-23. https:// doi.org/10.26879/852 palaeo-electronica.org/content/2018/2262-carnian-ostracods-from-turkey Copyright: July 2018 Paleontological Society. This is an open access article distributed under the terms of Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0), which permits users to copy and redistribute the material in any medium or format, provided it is not used for commercial purposes and the original author and source are credited, with indications if any changes are made. creativecommons.org/licenses/by-nc-sa/4.0/ FOREL, OZSV\u00c1RT, & MOIX: CARNIAN OSTRACODS FROM TURKEY", "keyphrases": ["triassic", "ostracod", "southern turkey", "palaeoenvironment"]}
{"id": "paleo.010291", "title": "A New Morphological Phylogeny of the Ophiuroidea (Echinodermata) Accords with Molecular Evidence and Renders Microfossils Accessible for Cladistics", "abstract": "Ophiuroid systematics is currently in a state of upheaval, with recent molecular estimates fundamentally clashing with traditional, morphology-based classifications. Here, we attempt a long overdue recast of a morphological phylogeny estimate of the Ophiuroidea taking into account latest insights on microstructural features of the arm skeleton. Our final estimate is based on a total of 45 ingroup taxa, including 41 recent species covering the full range of extant ophiuroid higher taxon diversity and 4 fossil species known from exceptionally preserved material, and the Lower Carboniferous Aganaster gregarius as the outgroup. A total of 130 characters were scored directly on specimens. The tree resulting from the Bayesian inference analysis of the full data matrix is reasonably well resolved and well supported, and refutes all previous classifications, with most traditional families discredited as poly- or paraphyletic. In contrast, our tree agrees remarkably well with the latest molecular estimate, thus paving the way towards an integrated new classification of the Ophiuroidea. Among the characters which were qualitatively found to accord best with our tree topology, we selected a list of potential synapomorphies for future formal clade definitions. Furthermore, an analysis with 13 of the ingroup taxa reduced to the lateral arm plate characters produced a tree which was essentially similar to the full dataset tree. This suggests that dissociated lateral arm plates can be analysed in combination with fully known taxa and thus effectively unlocks the extensive record of fossil lateral arm plates for phylogenetic estimates. Finally, the age and position within our tree implies that the ophiuroid crown-group had started to diversify by the Early Triassic.", "keyphrases": ["phylogeny", "ophiuroidea", "lateral arm plate"]}
{"id": "10.1111/j.1469-7998.2010.00758.x", "title": "Bizarre structures in dinosaurs: species recognition or sexual selection? A response to Padian and Horner", "abstract": "Since the mid-1970s, most investigators have agreed that the \u2018bizarre\u2019 structures (here referred to as \u2018exaggerated\u2019 structures) of dinosaurs \u2013 for example, the horns and frills of ceratopsids, the crests of lambeosaurine hadrosaurids, the domes of pachycephalosaurs \u2013 functioned first and foremost as signalling and combat structures used in mate competition (Farlow D Hopson, 1975; Molnar, 1977; Spassov, 1979; Ostrom & Wellnhoffer, 1986; Sampson, 1997, 2001; Dodson, Forster & Sampson, 2004). Padian & Horner (2010) argue that the mate competition hypothesis is not supported by available evidence, citing in particular the lack of data documenting sexual dimorphism within dinosaur species. In place of the mate competition model, they present a challenging and novel alternative, suggesting these traits functioned as species recognition features for identifying conspecifics, thereby facilitating social interactions such as herding, mating and parental care. Padian & Horner offer a pair of tests for distinguishing paleontological examples of exaggerated traits evolving under the influence of species recognition from those resulting primarily from sexual selection. The first test relates to the patterns of diversification of exaggerated structures, predicted to be random under the influence of species recognition and directional if driven by sexual selection. The second test invokes evidence of geographic overlap of closely related, contemporaneous species, thought to be a necessary condition for the evolution of exaggerated structures under the influence of species recognition (in part so as to avoid unwanted matings). These authors argue that known examples of exaggerated structures among dinosaurs pass both of these tests, indicating that species recognition is the preferred (though not necessarily sole) explanation. Padian & Horner highlight a major problem common to most previous studies addressing the function of dinosaurian exaggerated structures \u2013 lack of phylogenetic context. Comprehensive testing of adaptation hypotheses requires mapping of relevant characters onto independently derived phylogenies in order to search for evidence of evolutionary assembly of the purported adaptation. They also underline the importance of assessing the full range of alternative hypotheses as rigorously as possible, rather than accepting one explanation as the default. We fully support both of these contentions. Nevertheless, we disagree with several of the paper\u2019s central conclusions, including: (1) the necessary correlation of overt sexual dimorphism and sexual selection; (2) the required linkage between sexual selection with a directional pattern of diversification; (3) evidence for the geographical overlap of multiple closely related dinosaur taxa bearing exaggerated structures. In addition to countering these claims, we propose two alternative predictions that allow putative species recognition traits to be distinguished from sexually selected ones. With regard to the exaggerated structures of dinosaurs, the species recognition hypothesis fails both of these tests, and the sexual selection hypothesis remains by far the best-supported explanation. Citing Darwin (1871), Padian & Horner claim that sexual dimorphism is effectively the sine qua non of sexual selection. They argue further that the apparent absence of sexual dimorphism in dinosaurian exaggerated characters is Journal of Zoology", "keyphrases": ["sexual selection", "padian", "horner", "specie recognition trait"]}
{"id": "10.1017/pab.2018.13", "title": "Hyena as a predator of small mammals? Taphonomic analysis from the site of Bois Roche, France", "abstract": "Abstract. Feeding behaviors may differ between past and current predators due to differences in the environments inhabited by these species at different times. We provide an example of this behavioral variability in spotted hyena (Crocuta crocuta), for which our analysis of a late Pleistocene micromammal assemblage indicates that hyenas preyed upon small rodents, a feeding habit that is rarely observed today among hyenas. The Bois Roche cave site is situated at the edge of a low bluff overlooking the floodplain of a small stream in Cherves-Richemont (Charente, France). The deposits are dated by electron spin resonance (ESR) to about 69.7 \u00b1 4.1 Ka. Excavations at the site recovered fossil bones and teeth of large and small mammals, together with hyena coprolites. Water screening of the sediments produced large accumulations of rodent remains with low taxonomic diversity. Small mammal bones were recovered from hyena coprolites as well. Descriptions of small mammal bone modification, both from the sediments and coprolites, are reported here. The analysis yielded a distinct taphonomic pattern representative of large carnivores (over 30 kg), which differs from any other modern or fossil predator-accumulated microfaunal assemblage taphonomically analyzed to date. To our knowledge, previous studies of hyena diet have not recorded high concentrations of a single-rodent prey species. Weconclude that the lowspecies diversity of this small mammal assemblage most likely relates to a local abundance of the prey species due to an outbreak in the rodent population, rather than from specialist predator behavior and hunting technique.", "keyphrases": ["predator", "small mammal", "fossil bone", "hyena"]}
{"id": "paleo.000710", "title": "A new glimpse on trophic interactions of 100-million-year old lacewing larvae", "abstract": "Larvae of lacewings (Neuroptera) are known to be fierce predators. According to the morphology of fossil forms thisseems to have been the case already in the Early Cretaceous. While being predators, lacewing larvae are also food itemsfor other organisms. Here we report two pieces of amber from Myanmar providing instances of such cases. In one amberpiece several isolated stylets of lacewing larvae are preserved closely associated together. The most likely interpretationis that a predator preying on lacewing larvae has regurgitated or defecated these non-digestible pieces, yet the identityof the predator remains unclear. The other amber piece preserves a larva resembling modern day larvae of split-footedlacewings (Nymphidae). The larva has projections on its trunk, allowing it to wear a camouflaging cloak. In the headregion, a mite (Acari) is attached to the larva; more precisely, the entire anterior body region of the mite is apparentlyinserted into the lacewing larva. The mite is smaller than the larva. It is known from the modern fauna that stage 1 larvaeof Ascalaphidae can be attacked also by rather small predators, such as ants. The mite can therefore well be interpretedas a true predator instead of a parasite, especially considering the unusual mode of attachment. We briefly review interactionsof lacewing larvae with other organisms represented in amber from Myanmar and add two new pieces to thepuzzle of reconstructing the trophic interactions in the 100-million-year old amber forest.", "keyphrases": ["trophic interaction", "amber", "discussion"]}
{"id": "10.1029/2003PA000993", "title": "Nd and Pb isotope signatures of the clay-size fraction of Labrador Sea sediments during the Holocene: Implications for the inception of the modern deep circulation pattern", "abstract": "Holocene on the basis of sediment supply variations. For the last 12 kyr, three sources have contributed to the sediment mixture: the North American Shield, the Pan-African and Variscan crusts, and the Mid-Atlantic Ridge. Clay isotope signatures indicate two mixtures of sediment sources. The first mixture (12.2\u20136.5 ka) is composed of material derived from the North American shield and from a \u2018\u2018young\u2019\u2019 crustal source. From 6.5 ka onward the mixture is characterized by a young crustal component and by a volcanic component characteristic of the MidAtlantic Ridge. Since the significant decrease in proximal deglacial supplies, the evolution of the relative contributions of the sediment sources suggests major changes in the relative contributions of the deep water masses carried by the Western Boundary Undercurrent over the past 8.4 kyr. The progressive intensification of the Western Boundary Undercurrent was initially associated mainly with the transport of the Northeast Atlantic Deep Water mass until 6.5 ka and with the Denmark Strait Overflow Water thereafter. The establishment of the modern circulation at 3 ka suggests a reduced influence of the Denmark Strait Overflow Water, synchronous with the full appearance of the Labrador Seawater mass. Our isotopic data set emphasizes several changes in the relative contribution of the two major components of North Atlantic Deep Water throughout the Holocene. INDEX TERMS: 4267 Oceanography: General: Paleoceanography; 4558 Oceanography: Physical: Sediment transport; 1040 Geochemistry: Isotopic composition/chemistry; 9325 Information Related to Geographic Region: Atlantic Ocean; 9604 Information Related to Geologic Time: Cenozoic; KEYWORDS: clay-size fraction, sedimentary mixings, deep circulation, Nd and Pb isotopes, North Atlantic, Labrador Sea", "keyphrases": ["clay-size fraction", "holocene", "western boundary undercurrent"]}
{"id": "10.1130/B26269.1", "title": "Eocene climate record of a high southern latitude continental shelf: Seymour Island, Antarctica", "abstract": "A high-resolution record of Eocene paleotemperature variation is preserved within the high southern latitude, marine shelf succession of the La Meseta Formation on Seymour Island, off the NE side of the Antarctic Peninsula. 87 Sr/ 86 Sr ratios of bivalve shell carbonate indicate that the La Meseta Formation spans virtually the entire Eocene, and suggest the presence of an early middle Eocene unconformity. Paleoclimatic and paleoceanographic inferences are based on the stable oxygen and carbon isotope values of two genera of bivalves collected with a high degree of stratigraphic resolution within the formation, and with multiple replicate samples from each horizon. \u03b4 18 O data indicate roughly 10 \u00b0C of cooling from the early Eocene climatic optimum (~15 \u00b0C) through the end of the Eocene (minimum ~5 \u00b0C), much of which took place in two comparatively short intervals at ca. 52 and ca. 41 Ma. Many features of the isotope curves generated from this Eocene shelf section are apparent in \u03b4 18 O and \u03b4 13 C data from the Southern and global oceans, including warm intervals that likely correspond to the early and middle Eocene climatic optima (EECO and MECO). A rapid middle Eocene shift to much more positive values is the most signifi cant in the section and refl ects a drop to universally cooler temperatures in the late middle and late Eocene that might also be associated with a short-lived glacial advance. However, even using a somewhat depleted value for \u03b4 18 O of seawater in the Antarctic peninsular region, average Seymour Island shelf-water paleotemperatures did not reach freezing before the end of the Eocene. \u03b4 13 C data similarly refl ect the documented middle Eocene surface ocean enrichment followed by more negative values, but depletion is much more pronounced on Seymour Island and persists for the remainder of the Eocene, suggesting a combination of upwelling, metabolic effects, and/or atypical carbon cycling on the shelf in this region. Isotope data capture information about changes in the paleoenvironment that also had consequences for the biota, as published paleontological records document marked change in the nature of terrestrial and marine biota at this time. The fact that middle Eocene cooling and biotic turnover in the Peninsular region correspond well in time to the proposed initial opening of Drake Passage suggests that the formation of gateways, in addition to changes in pCO 2 , had signifi cant consequences for the Earth\u2019s climate system during the Paleogene.", "keyphrases": ["southern latitude", "seymour island", "early eocene"]}
{"id": "10.1111/j.1475-4983.2010.00936.x", "title": "New observations and reinterpretation on the enigmatic taxon Colombitherium (?Pyrotheria, Mammalia) from Colombia", "abstract": "Abstract:\u2002 The controversial taxon Colombitherium tolimense (Mammalia) (probably Late Eocene in age) from Colombia, although known for nearly 40\u2003years, still bears much mystery. Aside from the problematic ordinal attribution of the holotype and only specimen, its determination as an upper or lower jaw remains a highly debated issue. New observations include the presence of a contact facet on the distal face of the most posterior tooth, which indicates that the fragmentary jaw preserves three premolars and two molars; the M3, unpreserved but present, being most probably reduced. This new interpretation completely fits the morphology of the teeth. Furthermore, the shape of these latter and the deeper wear encompassed by their lingual part relative to the labial one is typical of upper dentition. This is in agreement with the internal curving of the roots of the anterior premolars and with several other arguments that lead interpreting the holotype of C. tolimense as a maxillary bearing P2\u2010M2. This new interpretation deepens the morphological gap between Colombitherium and other pyrotherians (except Proticia) and challenges further its referral to Pyrotheria. The peculiar morphology of Colombitherium relative to other pyrotherians is indeed striking. In fact, Colombitherium has nothing in common with pyrotherians but bilophodont cheek teeth, a feature largely widespread in placental mammals. It is here referred to ?Pyrotheria until additional evidence of its relationships is known. Associated with the putative removal of Proticia from Pyrotheria as argued by some authors, the hypothetical removal of Colombitherium from the order would adjust the widely accepted assumption that the pyrotherian bilophodont cheek teeth originated from bunodont cheek teeth. It would also make an origin from lophodont forms plausible. This in turn would have critical relevance, especially to the hypothesis that pyrotherians are notoungulates.", "keyphrases": ["pyrotheria", "mammalia", "new observation"]}
{"id": "10.1130/G31648.1", "title": "Molecular signature of chitin-protein complex in Paleozoic arthropods", "abstract": "The conventional geochemical view holds that the chitin and structural protein are not preserved in ancient fossils because they are readily degradable through microbial chitinolysis and proteolysis. Here we show a molecular signature of a relict chitin-protein complex preserved in a Pennsylvanian (310 Ma) scorpion cuticle and a Silurian (417 Ma) eurypterid cuticle via analysis with carbon, nitrogen, and oxygen X-ray absorption near edge structure (XANES) spectromicroscopy. High-resolution X-ray microscopy reveals the complex laminar variation in major biomolecule concentration across modern cuticle; XANES spectra highlight the presence of the characteristic functional groups of the chitin-protein complex. Modification of this complex is evident via changes in organic functional groups. Both fossil cuticles contain considerable aliphatic carbon relative to modern cuticle. However, the concentration of vestigial chitin-protein complex is high, 59% and 53% in the fossil scorpion and eurypterid, respectively. Preservation of a high-nitrogen-content chitin-protein residue in organic arthropod cuticle likely depends on condensation of cuticle-derived fatty acids onto a structurally modified chitin-protein molecular scaffold, thus preserving the remnant chitin-protein complex and cuticle from degradation by microorganisms.", "keyphrases": ["chitin-protein complex", "degradation", "molecular signature"]}
{"id": "10.1111/j.1096-3642.2008.00387.x", "title": "Taxonomy and palaeobiology of the largest-ever marsupial, Diprotodon Owen, 1838 (Diprotodontidae, Marsupialia)", "abstract": "To determine accurately the rates of late Pleistocene megafaunal loss, it is fundamentally important to have accurate taxonomic information for every species. In Australia, accurate taxonomic information is lacking for several Pleistocene groups, including the largest marsupial ever to live, Diprotodon Owen, 1838. Diprotodon taxonomy has been complicated by early nomenclatural problems and by the occurrence of two distinct size classes of individuals that do not reflect an ontogenetic series. Traditionally, the two size classes have been regarded as separate species. However, a taxonomic investigation of large samples (> 1000 teeth) of Diprotodon material from several different fossil localities in Queensland, New South Wales, South Australia and Victoria suggests that there is little evidence for the discrimination of more than one morphospecies. Thus, Diprotodon is here considered a monotypic genus and the single morphospecies, D. optatum Owen, 1838 is considered to have been highly sexually dimorphic. By drawing analogy with extant sexually dimorphic megaherbivores and marsupials, the large form was probably male, and the small form was probably female. Diprotodon optatum probably moved in small, gender-segregated herds, and exhibited a polygynous breeding strategy. As a single morphospecies, D. optatum had a near-continental geographical distribution, similar to that of extant megaherbivores, possibly indicating its niche as a habitat generalist. (c) 2008 The Linnean Society of London.", "keyphrases": ["marsupial", "diprotodon owen", "australia"]}
{"id": "paleo.005596", "title": "Proterozoic photosynthesis \u2013 a critical review", "abstract": "Chlorophyll\u2010based photosynthesis has fuelled the biosphere since at least the early Archean, but it was the ecological takeover of oxygenic cyanobacteria in the early Palaeoproterozoic, and of photosynthetic eukaryotes in the late Neoproterozoic, that gave rise to a recognizably modern ocean\u2013atmosphere system. The fossil record offers a unique view of photosynthesis in deep time, but is deeply compromised by differential preservation and non\u2010diagnostic morphologies. The pervasively polyphyletic expression of modern cyanobacterial phenotypes means that few Proterozoic fossils are likely to be members of extant clades; rather than billion\u2010year stasis, their similarity to modern counterparts is better interpreted as a combination of serial convergence and extinction, facilitated by high levels of horizontal gene transfer. There are few grounds for identifying cyanobacterial akinetes or crown\u2010group Nostocales in the Proterozoic record. Such recognition undermines the results of various ancestral state reconstruction analyses, as well as molecular clock estimates calibrated against demonstrably problematic Proterozoic fossils. Eukaryotic organisms are likely to have acquired their (stem\u2010group nostocalean) photoendosymbionts/plastids by at least the Palaeoproterozoic, but remained ecologically marginalized by incumbent cyanobacteria until the late Neoproterozoic appearance of suspension\u2010feeding animals.", "keyphrases": ["cyanobacteria", "eukaryote", "extant clade"]}
{"id": "10.1029/2009PA001831", "title": "Holocene marine 14C reservoir age variability: Evidence from 230Th\u2010dated corals in the South China Sea", "abstract": "The South China Sea (SCS) is well connected with the western Pacific and influenced by the East Asian monsoon. We have examined temporal variations in radiocarbon marine reservoir ages (R) and regional marine reservoir corrections (Delta R) of the SCS during the Holocene using paired measurements of AMS C-14 and TIMS Th-230 on 20 pristine corals. The results show large fluctuations in both R and Delta R values over the past 7500 years (yrs) with two distinct plateaus during 7.5-5.6 and 3.5-2.5 thousand calendar years before present (cal ka BP). The respective weighted mean Delta R values of these plateaus are 151 +/- 85 and 89 +/- 59 yrs, which are significantly higher than its modern value of -23 +/- 52 yrs. This suggests that using a constant modern Delta R value to calibrate C-14 dates of the SCS marine samples will introduce additional errors to the calibrated ages. Our results provide the first database for the Holocene R and Delta R values of the SCS for improved radiocarbon calibration of marine samples. We interpret the two Delta R plateaus as being related to two intervals with weakened El Nino - Southern Oscillation (ENSO) and intensified East Asian summer monsoon (EASM). This is because the C-14 content of the SCS surface water is controlled by both the C-14 concentration of the Pacific North Equatorial Current (NEC) which is in turn influenced by ENSO-induced upwelling along the Pacific equator and vertical upwelling within the SCS as a result of moisture transportation to midlatitude region to supply the EASM rainfall.", "keyphrases": ["coral", "south china sea", "holocene"]}
{"id": "10.1111/joa.12775", "title": "Developmental patterns and variation among early theropods", "abstract": "Understanding ontogenetic patterns is important in vertebrate paleontology because the assessed skeletal maturity of an individual often has implications for paleobiogeography, species synonymy, paleobiology, and body size evolution of major clades. Further, for many groups the only means of confidently determining ontogenetic status of an organism is through the destructive process of histological sampling. Although the ontogenetic patterns of Late Jurassic and Cretaceous dinosaurs are better understood, knowledge of the ontogeny of the earliest dinosaurs is relatively poor because most species\u2010level growth series known from these groups are small (usually, maximum of n ~ 5) and incomplete. To investigate the morphological changes that occur during ontogeny in early dinosaurs, I used ontogenetic sequence analysis (OSA) to reconstruct developmental sequences of morphological changes in the postcranial ontogeny of the early theropods Coelophysis bauri and Megapnosaurus rhodesiensis, both of which are known from large sample sizes (n = 174 and 182, respectively). I found a large amount of sequence polymorphism (i.e. intraspecific variation in developmental patterns) in both taxa, and especially in C. bauri, which possesses this variation in every element analyzed. Megapnosaurus rhodesiensis is similar, but it possesses no variation in the sequence of development of ontogenetic characters in the tibia and tarsus. Despite the large amount of variation in development, many characters occur consistently earlier or later in ontogeny and could therefore be important morphological features for assessing the relative maturity of other early theropods. Additionally, there is a phylogenetic signal to the order in which homologous characters appear in ontogeny, with homologous characters appearing earlier or later in developmental sequences of early theropods and the close relatives of dinosaurs, silesaurids. Many of these morphological features are important characters for the reconstruction of archosaurian phylogeny (e.g. trochanteric shelf). Because these features vary in presence or appearance with ontogeny, these characters should be used with caution when undertaking phylogenetic analyses in these groups, since a specimen may possess certain character states owing to ontogenetic stage, not evolutionary relationships.", "keyphrases": ["early theropod", "growth series", "ontogenetic sequence analysis", "megapnosaurus rhodesiensis", "developmental pattern"]}
{"id": "10.1111/pala.12060", "title": "Tommotiids from the early Cambrian (Series 2, Stage 3) of Morocco and the evolution of the tannuolinid scleritome and setigerous shell structures in stem group brachiopods", "abstract": "An assemblage of tannuolinid sclerites is described from the Amouslek Formation (Souss Basin) of the Anti\u2010Atlas Mountains in Morocco. The assemblage contains two species, Tannuolina maroccana n. sp., which is represented by a small number of mitral and sellate sclerites, and Micrina sp., represented by a single mitral sclerite. Tannuolina maroccana differs from other species of the genus in the presence of both bilaterally symmetrical and strongly asymmetrical sellate sclerites. This observation suggests that the scleritome of Tannuolina was more complex than previously thought and that this tommotiid may have held a more basal position in the brachiopod stem group than previously assumed. The shell structure of both T. maroccana and Micrina sp. is well preserved and exhibits two fundamentally different sets of tubular structures, only one of which was likely to contain shell\u2010penetrating setae. Based on these observations, the structure of the tannuolinid shell is discussed and its implications for the evolution of tubular microstructures in stem and crown group brachiopods are analysed.", "keyphrases": ["morocco", "shell structure", "tommotiid"]}
{"id": "paleo.004932", "title": "The endocranium of the theropod dinosaur Ceratosaurus studied with computed tomography", "abstract": "A well preserved specimen of the theropod Ceratosaurus from the Upper Jurassic Morrison Formation of western Colorado was recently described and given the name C. magnicornis. The systematics of the genus is outside the scope of the present study but, as a generally accepted basal tetanuran, the braincase was CT scanned to provide a description of the endocranium, inner ear, pneumatic, and venous sinus systems in a primitive member of this clade. Five major subregions of the theropod endocranium are distinguished for the purpose of simplifying cranial computed tomographic interpretation and to provide a systematic means of comparison to other endocrania. The skull morphology of Ceratosaurus influences the overall braincase morphology and the number and distribution of the major foramina. The low pontine angle and relatively unflexed braincase is considered a more primitive character. The orientation of the horizontal semicircular canal confirms a rather horizontal and unerect posture of the head and neck. As in birds, the narrower skull morphology of Ceratosaurus is associated with fewer cranial nerve foramina. Additionally, the maxillary dominated dentigerous upper jaw of Ceratosaurus is felt to share with the alligator a large rostrally directed maxillary division of the trigeminal nerve and a small ophthalmic branch. The upper bill of birds, being dominated by the premaxillary and lacking teeth, is innervated predominantly by the ophthalmic division of the trigeminal nerve. For this reason, avian-based cranial nerve reconstructions are felt to be inappropriate for basal theropods. Ceratosaurus skull pneumatization and possible evidence of olfactory conchal structures is on the other hand very avian in character. Based on computed tomography, Ceratosaurus is determined to have possessed a typical basal theropod endocranium and bipedal vestibular system similar to Allosaurus.", "keyphrases": ["endocranium", "ceratosaurus", "tomography"]}
{"id": "10.1130/b35646.1", "title": "A Chronostratigraphic Framework for the Rise of the Ediacaran Macrobiota: New Constraints from Mistaken Point Ecological Reserve, Newfoundland", "abstract": "\n The Conception and St. John\u2019s Groups of southeastern Newfoundland contain some of the oldest known fossils of the Ediacaran macrobiota. The Mistaken Point Ecological Reserve UNESCO World Heritage Site is an internationally recognized locality for such fossils and hosts early evidence for both total group metazoan body fossils and metazoan-style locomotion. The Mistaken Point Ecological Reserve sedimentary succession includes \u223c1500 m of fossil-bearing strata containing numerous dateable volcanogenic horizons, and therefore offers a crucial window into the rise and diversification of early animals. Here we present six stratigraphically coherent radioisotopic ages derived from zircons from volcanic tuffites of the Conception and St. John\u2019s Groups at Mistaken Point Ecological Reserve. The oldest architecturally complex macrofossils, from the upper Drook Formation, have an age of 574.17 \u00b1 0.66 Ma (including tracer calibration and decay constant uncertainties). The youngest rangeomorph fossils from Mistaken Point Ecological Reserve, in the Fermeuse Formation, have a maximum age of 564.13 \u00b1 0.65 Ma. Fossils of the famous \u201cE\u201d Surface are confirmed to be 565.00 \u00b1 0.64 Ma, while exceptionally preserved specimens on the \u201cBrasier\u201d Surface in the Briscal Formation are dated at 567.63 \u00b1 0.66 Ma. We use our new ages to construct an age-depth model for the sedimentary succession, constrain sedimentary accumulation rates, and convert stratigraphic fossil ranges into the time domain to facilitate integration with time-calibrated data from other successions. Combining this age model with compiled stratigraphic ranges for all named macrofossils within the Mistaken Point Ecological Reserve succession, spanning 76 discrete fossil-bearing horizons, enables recognition and interrogation of potential evolutionary signals. Peak taxonomic diversity is recognized within the Mistaken Point and Trepassey Formations, and uniterminal rangeomorphs with undisplayed branching architecture appear several million years before multiterminal, displayed forms. Together, our combined stratigraphic, paleontological, and geochronological approach offers a holistic, time-calibrated record of evolution during the mid\u2013late Ediacaran Period and a framework within which to consider other geochemical, environmental, and evolutionary data sets.", "keyphrases": ["ediacaran macrobiota", "newfoundland", "rangeomorph fossil"]}
{"id": "10.1017/S0094837300016158", "title": "Limited membership in Pleistocene reef coral assemblages from the Huon Peninsula, Papua New Guinea: constancy during global change", "abstract": "One of the most intriguing questions in community ecology remains unanswered: Are ecological communities open assemblages with each species reacting individually to environmental change, or are they integrated units consisting of multispecies assemblages acting in concert? I address this question for marine organisms by examining the taxonomic composition and diversity of Indo-Pacific reef coral communities that have undergone repeated global change between 125 and 30 Ka (thousand years before present). Investigation of community constancy through time relies on two critical questions: (1) Are there significant differences in taxonomic composition among communities from different times? and if not, (2) Are the observed patterns in temporal similarity significantly different from expected patterns resulting from a random sampling of the available within-habitat species pool? Constancy in taxonomic composition and species richness of Pleistocene reef coral assemblages is maintained through a 95-k.y. interval in the raised reef terraces of the Huon Peninsula, Papua New Guinea. Fossil reef coral assemblages show limited membership in species composition despite repeated exposure to marked fluctuations in sea level (up to 120 m) and sea-surface temperatures (up to 6\u00b0). During the 95-k.y. interval, the reefs experienced nine cycles of perturbation and subsequent reassembly with similar species composition. Spatial differences in reef coral species composition were greater among the three study sites than among reefs of different ages. Thus local environmental parameters associated with riverine and terrestrial sources had a greater influence on reef coral composition than global climate and sea level changes. The ecological dynamics of reef communities from Papua New Guinea are in marked contrast to those of Quaternary terrestrial and level bottom marine communities which appear to show unlimited community membership on both larger and smaller time scales. Differences in community assembly among ecosystems mean either that coral reefs are fundamentally different or that different ecological patterns and processes are occurring at different temporal scales.", "keyphrases": ["huon peninsula", "global change", "limited membership"]}
{"id": "paleo.010564", "title": "Birds of a Feather: Neanderthal Exploitation of Raptors and Corvids", "abstract": "The hypothesis that Neanderthals exploited birds for the use of their feathers or claws as personal ornaments in symbolic behaviour is revolutionary as it assigns unprecedented cognitive abilities to these hominins. This inference, however, is based on modest faunal samples and thus may not represent a regular or systematic behaviour. Here we address this issue by looking for evidence of such behaviour across a large temporal and geographical framework. Our analyses try to answer four main questions: 1) does a Neanderthal to raptor-corvid connection exist at a large scale, thus avoiding associations that might be regarded as local in space or time?; 2) did Middle (associated with Neanderthals) and Upper Palaeolithic (associated with modern humans) sites contain a greater range of these species than Late Pleistocene paleontological sites?; 3) is there a taphonomic association between Neanderthals and corvids-raptors at Middle Palaeolithic sites on Gibraltar, specifically Gorham's, Vanguard and Ibex Caves? and; 4) was the extraction of wing feathers a local phenomenon exclusive to the Neanderthals at these sites or was it a geographically wider phenomenon?. We compiled a database of 1699 Pleistocene Palearctic sites based on fossil bird sites. We also compiled a taphonomical database from the Middle Palaeolithic assemblages of Gibraltar. We establish a clear, previously unknown and widespread, association between Neanderthals, raptors and corvids. We show that the association involved the direct intervention of Neanderthals on the bones of these birds, which we interpret as evidence of extraction of large flight feathers. The large number of bones, the variety of species processed and the different temporal periods when the behaviour is observed, indicate that this was a systematic, geographically and temporally broad, activity that the Neanderthals undertook. Our results, providing clear evidence that Neanderthal cognitive capacities were comparable to those of Modern Humans, constitute a major advance in the study of human evolution.", "keyphrases": ["feather", "neanderthals", "raptor", "ornament", "middle palaeolithic site"]}
{"id": "10.1002/jez.b.21115", "title": "Origin of dental occlusion in tetrapods: signal for terrestrial vertebrate evolution?", "abstract": "Evolutionary changes of the dentition in tetrapods can be associated with major events in the history of terrestrial vertebrates. Dental occlusion, the process by which teeth from the upper jaw come in contact with those in the lower jaw, appears first in the fossil record in amniotes and their close relatives near the Permo-Carboniferous boundary approximately 300 million years ago. This evolutionary innovation permitted a dramatic increase in the level of oral processing of food in these early tetrapods, and has been generally associated with herbivory. Whereas herbivory in extinct vertebrates is based on circumstantial evidence, dental occlusion provides direct evidence about feeding strategies because jaw movements can be reconstructed from the wear patterns of the teeth. Examination of the evolution of dental occlusion in Paleozoic tetrapods within a phylogenetic framework reveals that this innovation developed independently in several lineages of amniotes, and is represented by a wide range of dental and mandibular morphologies. Dental occlusion also developed within diadectomorphs, the sister taxon of amniotes. The independent, multiple acquisition of this feeding strategy represents an important signal in the evolution of complex terrestrial vertebrate communities, and the first steps in the profound changes in the pattern of trophic interactions in terrestrial ecosystems.", "keyphrases": ["dental occlusion", "tetrapod", "tooth"]}
{"id": "10.1002/rcm.7878", "title": "Carbonate clumped isotope analyses with the long-integration dual-inlet (LIDI) workflow: scratching at the lower sample weight boundaries.", "abstract": "RATIONALE\nClumped isotope analyses (\u039447 ) of carbonates by dual inlet (DI) mass spectrometry require long integration times to reach the necessary high precision due to the low abundance of the rare isotopologue 13 C18 O16 O. Traditional DI protocols reach this only with large amounts of sample and/or a large number of replicates as a large portion of the analyte gas is wasted. We tested an improved analytical workflow that significantly reduces the sample sizes and total analysis time per sample while preserving precision and accuracy.\n\n\nMETHODS\nWe implemented the LIDI (long-integration dual-inlet) protocol to measure carbonates in micro-volume mode using a Kiel IV carbonate device coupled to a Thermo Scientific 253 Plus isotope ratio mass spectrometer without the new 1013 ohm amplifier technology. The LIDI protocol includes a single measurement of the sample gas (600\u00a0s integration) followed by a single measurement of the working gas (WG) with the same integration time.\n\n\nRESULTS\nThe \u039447 measurements of four calcite standards over a period of 5\u00a0weeks demonstrate excellent long-term stability with a standard deviation of \u00b10.021 to \u00b10.025 \u2030 for the final values of the individual aliquots. The \u039447 analyses of a coral, four foraminifera and a calcite precipitated in the laboratory demonstrate that 14 replicates of 90 to 120\u00a0\u03bcg are sufficient to achieve an external precision of \u00b10.007 \u2030 (1SE) or of \u00b10.013 \u2030 at the 95% confidence level.\n\n\nCONCLUSIONS\nThis study demonstrates that by using a Kiel IV-253 Plus system with LIDI it is possible to achieve the same analytical precision as conventional DI measurements with at least a factor of 40 less sample material. With the new 1013 ohm resistor technology there is the potential to reduce the required sample material even more. This opens new avenues of research in paleoceanography, paleoclimatology, low-temperature diagenesis and other currently sample size limited applications. Copyright \u00a9 2017 John Wiley & Sons, Ltd.", "keyphrases": ["long-integration dual-inlet", "workflow", "large number", "carbonate"]}
{"id": "10.1666/09029.1", "title": "Permian\u2013Triassic land-plant diversity in South China: Was there a mass extinction at the Permian/Triassic boundary?", "abstract": "Abstract Diversity dynamics of the Permian\u2013Triassic land plants in South China are studied by analyzing paleobotanical data. Our results indicate that the total diversity of land-plant megafossil genera and species across the Permian/Triassic boundary (PTB) of South China underwent a progressive decline from the early Late Permian (Wuchiapingian) to the Early-Middle Triassic. In contrast, the diversity of land-plant microfossil genera exhibited only a small fluctuation across the PTB of South China, showing an increase at the PTB. Overall, land plants across the PTB of South China show a greater stability in diversity dynamics than marine faunas. The highest extinction rate (90.91%) and the lowest origination rate (18.18%) of land-plant megafossil genera occurred at the early Early Triassic (Induan), but the temporal duration of the higher genus extinction rates (>60%) in land plants was about 23.4 Myr, from the Wuchiapingian to the early Middle Triassic (Anisian), which is longer than that of the coeval marine faunas (3\u201311 Myr). Moreover, the change of genus turnover rates in land-plant megafossils steadily fluctuated from the late Early Permian to the Late Triassic. More stable diversity and turnover rate as well as longer extinction duration suggest that land plants near the PTB of South China may have been involved in a gradual floral reorganization and evolutionary replacement rather than a mass extinction like those in the coeval marine faunas.", "keyphrases": ["south china", "mass extinction", "triassic boundary", "land plant"]}
{"id": "10.7717/peerj.1509", "title": "A late-surviving apatemyid (Mammalia: Apatotheria) from the latest Oligocene of Florida, USA", "abstract": "A new species of Apatemyidae, Sinclairella simplicidens, is based on four isolated teeth that were screenwashed from fissure fillings at the late Oligocene Buda locality, Alachua County, Florida. Compared to its only congener Sinclairella dakotensis, the new species is characterized by upper molars with more simplified crowns, with the near absence of labial shelves and stylar cusps except for a strong parastyle on M1, loss of paracrista and paraconule on M2 (paraconule retained but weak on M1), lack of anterior cingulum on M1\u2013M3, straighter centrocristae, smaller hypocone on M1 and M2, larger hypocone on M3, distal edge of M2 continuous from hypocone to postmetacrista supporting a large posterior basin, and with different tooth proportions in which M2 is the smallest rather than the largest molar in the toothrow. The relatively rare and poorly-known family Apatemyidae has a long temporal range in North America from the late Paleocene (early Tiffanian) to early Oligocene (early Arikareean). The new species from Florida significantly extends this temporal range by roughly 5 Ma to the end of the Paleogene near the Oligocene-Miocene boundary (from early Arikareean, Ar1, to late Arikareean, Ar3), and greatly extends the geographic range of the family into eastern North America some 10\u00b0 of latitude farther south and 20\u00b0 of longitude farther east (about 2,200 km farther southeast) than previously known. This late occurrence probably represents a retreat of this subtropically adapted family into the Gulf Coastal Plain subtropical province at the end of the Paleogene and perhaps the end of the apatemyid lineage in North America.", "keyphrases": ["oligocene", "florida", "apatemyidae"]}
{"id": "10.1080/02724634.1993.10011489", "title": "Trilophosuchus Rackhami gen. et sp. nov., a New Crocodilian from the Early Miocene Limestones of Riversleigh, Northwestern Queensland", "abstract": "ABSTRACT A new crocodilian from the Miocene of northwestern Queensland is described as Trilophosuchus rackhami, gen. et sp. nov. This is a small crocodilian reminiscent of Osteolaemus and Paleosuchus. However, resemblance to these forms appears to be the result of convergence on a short-snouted adaptive form. Trilophosuchus also resembles extinct taxa such as Notosuchus, Araripesuchus, Libycosuchus, Theriosuchus, and Protosuchus. Trilophosuchus displays some striking autapomorphies such as three longitudinal crests on the skull roof and narrow, elongate supratemporal fenestrae. The structure of the occipital surface suggests that Trilophosuchus held its head above the body. The insertions of muscles on the occipital surface are more consistent with a terrestrial, rather than aquatic, mode of life. A phylogenetic analysis suggest that Trilophosuchus is most closely related to four other Australian taxa of extinct crocodilians and should be included in the Australian Tertiary crocodilian radiation.", "keyphrases": ["new crocodilian", "northwestern queensland", "trilophosuchus"]}
{"id": "10.1080/14772019.2012.693954", "title": "Lower Cretaceous origin of long-distance mate finding behaviour in Hymenoptera (Insecta)", "abstract": "Flabellate antennae have evolved numerous times in males of several insect groups where they carry olfactory receptor neurons enabling the individuals to locate females over long distances. In Recent Hymenoptera, one of the largest species radiations among the Animalia, flabellate antennae are relatively uncommon. Here we describe Atefia rasnitsyni gen. et sp. nov. from the Lower Cretaceous Crato Formation of Brazil, representing the first fossil hymenopteran with a biflabellate antenna. The fossil indicates that long-distance mate finding behaviour in Hymenoptera was already well established in the Lower Cretaceous. The new fossil is taxonomically challenging and shares morphological characters with Recent Pergidae and Diprionidae. However, it lacks definite diagnostic features of either family and is here left unplaced as an early lineage of Tenthredinoidea. The occurrence and structural diversity of flabellate antennae in Recent Tenthredinoidea is discussed in a phylogenetic framework. http://zoobank.org/urn:lsid:zoobank.org:pub:D69866FA-831C-4B72-8E18-1CFA5B87D3DA", "keyphrases": ["long-distance mate", "behaviour", "hymenoptera", "biflabellate antennae", "female attractant"]}
{"id": "10.2307/1382445", "title": "Dietary adaptation of some extinct ruminants determined by premaxillary shape", "abstract": "Extant ungulates can be divided into three dietary categories: browsers, grazers, and mixed feeders. Dietary adaptations can be differentiated in extant ruminants based upon analysis of premaxillary shape. This study applies methods to determine the dietary adaptations of extinct ungulates through analysis of premaxillary shapes. While browsers have pointed premaxillae and grazers have square premaxillae, mixed feeders have premaxillae that are a shape intermediate to the browsers and grazers, sometimes accompanied by an indentation on either side of the incisive foramen, which results in a club-shaped premaxilla. Cranioceras skinneri (Palaeomerycidae), Dromomeryx whitfordi (Palaeomerycidae), Palaeotragus coelophrys, \"Palaeotragus\" primaevus, an undetermined species from the Baringo Basin of Kenya (Giraffidae), Texoceros guimonensis (Antilocapridae), and Turcocerus grangeri (Bovidae) were found browsers; Aletomeryx gracilis (Palaeomerycidae), Bramatherium megacephalum (Giraffidae), Cosoryx furcatus (Antilocapridae), Honanotherium schlosseri (Giraffidae), Samotherium boissieri (Giraffidae), Samotherium neumayri (Giraffidae), Samotherium sp. nov., Sivatherium giganteum (Giraffidae), and Synthetoceras tricornatus (Protoceratidae) were grazers; and Merycodus necatus (Antilocapridae) and Palaeotragus rouenii (Giraffidae) were mixed feeders.", "keyphrases": ["ruminant", "premaxillary shape", "ungulate", "grazer", "dietary adaptation"]}
{"id": "paleo.006761", "title": "Hierarchical complexity and the size limits of life", "abstract": "Over the past 3.8 billion years, the maximum size of life has increased by approximately 18 orders of magnitude. Much of this increase is associated with two major evolutionary innovations: the evolution of eukaryotes from prokaryotic cells approximately 1.9 billion years ago (Ga), and multicellular life diversifying from unicellular ancestors approximately 0.6 Ga. However, the quantitative relationship between organismal size and structural complexity remains poorly documented. We assessed this relationship using a comprehensive dataset that includes organismal size and level of biological complexity for 11 172 extant genera. We find that the distributions of sizes within complexity levels are unimodal, whereas the aggregate distribution is multimodal. Moreover, both the mean size and the range of size occupied increases with each additional level of complexity. Increases in size range are non-symmetric: the maximum organismal size increases more than the minimum. The majority of the observed increase in organismal size over the history of life on the Earth is accounted for by two discrete jumps in complexity rather than evolutionary trends within levels of complexity. Our results provide quantitative support for an evolutionary expansion away from a minimal size constraint and suggest a fundamental rescaling of the constraints on minimal and maximal size as biological complexity increases.", "keyphrases": ["complexity", "cell", "organismal size"]}
{"id": "10.5194/gmd-4-571-2011", "title": "Pliocene Model Intercomparison Project (PlioMIP): experimental design and boundary conditions (Experiment 2)", "abstract": "Abstract. The Palaeoclimate Modelling Intercomparison Project has expanded to include a model intercomparison for the mid-Pliocene warm period (3.29 to 2.97 million yr ago). This project is referred to as PlioMIP (the Pliocene Model Intercomparison Project). Two experiments have been agreed upon and together compose the initial phase of PlioMIP. The first (Experiment 1) is being performed with atmosphere-only climate models. The second (Experiment 2) utilises fully coupled ocean-atmosphere climate models. Following on from the publication of the experimental design and boundary conditions for Experiment 1 in Geoscientific Model Development, this paper provides the necessary description of differences and/or additions to the experimental design for Experiment 2.", "keyphrases": ["pliomip", "experimental design", "boundary condition", "warm period"]}
{"id": "10.1163/1937240X-00002124", "title": "Neotropical Macrobrachium (Caridea: Palaemonidae): on the biology, origin, and radiation of freshwater-invading shrimp.", "abstract": "Comprising >240 extant species, Macrobrachium Bate, 1868 is the most speciose caridean genus in Palaemonidae. It is generally considered as a monophyletic clade that lives exclusively in limnic and brackish habitats. Thus, it may provide a suitable model for the reconstruction of evolutionary transitions of euryhaline shrimp from ancestral state of living in the sea towards invasions of freshwater environments. Reviewing patterns of the biology (adaptative physiological and reproductive traits) and modern biogeographic distribution of this clade, I propose here a scenario for its tentative origin and evolutionary invasion of limnic inland waters, especially in the Americas. Macrobrachium shows: 1) a world-wide tropical to subtropical distribution, with only few species occurring in temperate regions and none in cold waters at high latitudes; 2) a clear preference for low salinity conditions (based on strong osmoregulatory capacities); 3) larval export strategies in coastal species (with diadromous migrations and invariably an extended larval development in estuaries); and 4) almost exclusively an abbreviated and lecithotrophic mode of larval development in hololimnetic inland species. The extant patterns of geographic distribution of this genus are strikingly disjunct, with completely separate groups of species occurring in the Indo-Pacific region (where maximum diversity occurs), inWest Africa, and in the Americas. In a clade with common ancestry, this pattern can only be explained with a Tethyan origin and dispersal. Hence, I suggest an origin of ancestral Macrobrachium in theMesozoic. As a consequence of the breakup of Gondwana and fragmentation of the Tethys Sea, mainly during the Late Cretaceous and Palaeogene, Neotropical and West African clades became isolated from the remaining congeners and thus can be considered as Tethyan relicts. In the Neotropics, the closure of the Central American landbridge in the Late Pliocene was a significant vicariant event that caused diversification of coastal Macrobrachium in the Caribbean region, so that two separate groups of extant species live now in the Atlantic and Pacific drainage systems. The distribution of hololimnetic inland species can be explained by continental floodings occurring during the Miocene sea level highstand. Due to concomitant sub-Andean subsidence and impounded by the uplift of the Andes, the huge Pebas wetland system was formed at that time, covering the vast proto-Amazonas-Orinoco catchment area with sub-Andean lowlands reaching from Columbia to southern Bolivia. This allowed for incursions of marine-derived lineages of euryhaline shrimp and other coastal animals throughout northern and central South America, followed by adaptive radiations in freshwater. After the breaching of the continental divide (mainly the Purus Arch) in central Amazonia, probably in the Late Miocene, the modern eastward flow of the Amazon developed, draining to the Atlantic Ocean. Fluctuation but trending to a general decrease in global sea levels during the Pliocene and Pleistocene caused fragmentation of previously interconnected inland waters, promoting vicariant diversification of hololimnetic lineages. However, some hydrological connections between different catchment areas remained transitorily open, providing limited dispersal routes that also may have influenced speciation, e.g., through hybridisation. Thus, the modern distribution patterns of Neotropical Macrobrachium reflect interacting effects of tectonic events including Andean orogeny and the closure of the Panamaian landbridge, Miocene marine incursions, and possible cross-drainage dispersal through historical connections between river basins.", "keyphrases": ["palaemonidae", "shrimp", "sea", "freshwater environment", "neotropical macrobrachium"]}
{"id": "paleo.010578", "title": "Climate-driven environmental changes around 8,200 years ago favoured increases in cetacean strandings and Mediterranean hunter-gatherers exploited them", "abstract": "Cetacean mass strandings occur regularly worldwide, yet the compounded effects of natural and anthropogenic factors often complicate our understanding of these phenomena. Evidence of past stranding episodes may, thus, be essential to establish the potential influence of climate change. Investigations on bones from the site of Grotta dell\u2019Uzzo in North West Sicily (Italy) show that the rapid climate change around 8,200 years ago coincided with increased strandings in the Mediterranean Sea. Stable isotope analyses on collagen from a large sample of remains recovered at this cave indicate that Mesolithic hunter-gatherers relied little on marine resources. A human and a red fox dating to the 8.2-kyr-BP climatic event, however, acquired at least one third of their protein from cetaceans. Numerous carcasses should have been available annually, for at least a decade, to obtain these proportions of meat. Our findings imply that climate-driven environmental changes, caused by global warming, may represent a serious threat to cetaceans in the near future.", "keyphrases": ["stranding", "climate-driven environmental change", "isotope analysis"]}
{"id": "paleo.013128", "title": "Early Triassic marine reptile representing the oldest record of unusually small eyes in reptiles indicating non-visual prey detection", "abstract": "The end-Permian mass extinction (EPME) led to reorganization of marine predatory communities, through introduction of air-breathing top predators, such as marine reptiles. We report two new specimens of one such marine reptile, Eretmorhipis carrolldongi, from the Lower Triassic of Hubei, China, revealing superficial convergence with the modern duckbilled platypus (Ornithorhynchus anatinus), a monotreme mammal. Apparent similarities include exceptionally small eyes relative to the body, snout ending with crura with a large internasal space, housing a bone reminiscent of os paradoxum, a mysterious bone of platypus, and external grooves along the crura. The specimens also have a rigid body with triangular bony blades protruding from the back. The small eyes likely played reduced roles during foraging in this animal, as with extant amniotes (group containing mammals and reptiles) with similarly small eyes. Mechanoreceptors on the bill of the animal were probably used for prey detection instead. The specimens represent the oldest record of amniotes with extremely reduced visual capacity, utilizing non-visual cues for prey detection. The discovery reveals that the ecological diversity of marine predators was already high in the late Early Triassic, and challenges the traditional view that the ecological diversification of marine reptiles was delayed following the EPME.", "keyphrases": ["reptile", "small eye", "prey detection", "mass extinction", "ecological diversity"]}
{"id": "paleo.007300", "title": "Ancient whales did not filter feed with their teeth", "abstract": "The origin of baleen whales (Mysticeti), the largest animals on Earth, is closely tied to their signature filter-feeding strategy. Unlike their modern relatives, archaic whales possessed a well-developed, heterodont adult dentition. How these teeth were used, and what role their function and subsequent loss played in the emergence of filter feeding, is an enduring mystery. In particular, it has been suggested that elaborate tooth crowns may have enabled stem mysticetes to filter with their postcanine teeth in a manner analogous to living crabeater and leopard seals, thereby facilitating the transition to baleen-assisted filtering. Here we show that the teeth of archaic mysticetes are as sharp as those of terrestrial carnivorans, raptorial pinnipeds and archaeocetes, and thus were capable of capturing and processing prey. By contrast, the postcanine teeth of leopard and crabeater seals are markedly blunter, and clearly unsuited to raptorial feeding. Our results suggest that mysticetes never passed through a tooth-based filtration phase, and that the use of teeth and baleen in early whales was not functionally connected. Continued selection for tooth sharpness in archaic mysticetes is best explained by a feeding strategy that included both biting and suction, similar to that of most living pinnipeds and, probably, early toothed whales (Odontoceti).", "keyphrases": ["whale", "tooth", "mysticete"]}
{"id": "10.1126/science.1193221", "title": "Loss of Carbon from the Deep Sea Since the Last Glacial Maximum", "abstract": "Moving Carbon During the last glacial maximum, approximately 23,000 years ago, both the atmosphere and the terrestrial biosphere contained much less carbon than in the immediately preindustrial era. The carbon must have been stored in the deep ocean, and the transfer of carbon to the air and land during deglaciation must have affected the carbonate chemistry and carbon isotopic composition of the sea. Yu et al. (p. 1084) estimated how deep-water carbonate concentrations changed over the course of the last deglaciation and combined their results with 13C/12C data to show that carbon released by the deep ocean between 17.5 and 14.5 thousand years ago mostly stayed in the atmosphere as CO2, while between 14 and 10 thousand years ago, a substantial fraction was absorbed by the terrestrial biosphere. Carbon loss from the ocean to the atmosphere and terrestrial biosphere occurred at different rates in the last deglaciation. Deep-ocean carbonate ion concentrations ([CO32\u2013]) and carbon isotopic ratios (\u03b413C) place important constraints on past redistributions of carbon in the ocean-land-atmosphere system and hence provide clues to the causes of atmospheric CO2 concentration changes. However, existing deep-sea [CO32\u2013] reconstructions conflict with one another, complicating paleoceanographic interpretations. Here, we present deep-sea [CO32\u2013] for five cores from the three major oceans quantified using benthic foraminiferal boron/calcium ratios since the last glacial period. Combined benthic \u03b413C and [CO32\u2013] results indicate that deep-sea-released CO2 during the early deglacial period (17.5 to 14.5 thousand years ago) was preferentially stored in the atmosphere, whereas during the late deglacial period (14 to 10 thousand years ago), besides contributing to the contemporary atmospheric CO2 rise, a substantial portion of CO2 released from oceans was absorbed by the terrestrial biosphere.", "keyphrases": ["carbon", "glacial maximum", "boron"]}
{"id": "paleo.006170", "title": "Global climate change driven by soot at the K-Pg boundary as the cause of the mass extinction", "abstract": "The mass extinction of life 66 million years ago at the Cretaceous/Paleogene boundary, marked by the extinctions of dinosaurs and shallow marine organisms, is important because it led to the macroevolution of mammals and appearance of humans. The current hypothesis for the extinction is that an asteroid impact in present-day Mexico formed condensed aerosols in the stratosphere, which caused the cessation of photosynthesis and global near-freezing conditions. Here, we show that the stratospheric aerosols did not induce darkness that resulted in milder cooling than previously thought. We propose a new hypothesis that latitude-dependent climate changes caused by massive stratospheric soot explain the known mortality and survival on land and in oceans at the Cretaceous/ Paleogene boundary. The stratospheric soot was ejected from the oil-rich area by the asteroid impact and was spread globally. The soot aerosols caused sufficiently colder climates at mid-high latitudes and drought with milder cooling at low latitudes on land, in addition to causing limited cessation of photosynthesis in global oceans within a few months to two years after the impact, followed by surfacewater cooling in global oceans in a few years. The rapid climate change induced terrestrial extinctions followed by marine extinctions over several years.", "keyphrases": ["climate change", "soot", "mass extinction", "aerosol", "stratosphere"]}
{"id": "paleo.000292", "title": "Body mass estimation in Triassic cynodonts from Argentina based on limb variables", "abstract": "in from based on Body mass estimations for extinct taxa are fundamental in palaeobiological reconstructions, but little work has been done on this topic for non-mammaliaform cynodonts (NMC), the diverse and abundant Permo-Cretaceous forerunners of mammals. Here, we estimated the body mass of five species of NMC cynognathians by linear measurements and circumferences of postcranial elements (humeri and femora) from 14 specimens from Triassic units of the Ischigualasto-Villa Union Basin located between San Juan and La Rioja provinces, and the Cuyo and San Rafael basins, both in Mendoza province, Argentina. For this purpose, we used predictive formulas available in the literature based on variables on appendicular skeleton of different extant groups of mammals and reptiles. Geometric similarity using skull length was applied to provide an estimation of adult masses for species with only samples of juvenile and subadult limb bones. A broad body mass range was recorded. Small traversodontids such as Andescynodon mendozensis and Pascualgnathus polanskii were between 1 to 3.5 kg. Medium-sized traversodontids include adult Massetognathus pascuali with masses from 20 to 40 kg, and the adult forms of large-sized cynognathians like Cynognathus crateronotus and Exaeretodon argentinus reached or surpassed 100 kg. The morphological variations in the skull and the different body sizes observed between traversodontids are interpreted as reflecting different types of diets where small-sized traversodontids had a generalist diet, and the medium/large-sized traversodontids were herbivorous. Finally, palaeoecological working hypotheses regarding cranial and dental morphology, body mass, and their possible relation with diet in non-mammaliaform cynodonts of South America are offered. which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.", "keyphrases": ["cynodont", "argentina", "body mass estimation"]}
{"id": "paleo.009910", "title": "Controls on Gut Phosphatisation: The Trilobites from the Weeks Formation Lagerst\u00e4tte (Cambrian; Utah)", "abstract": "Despite being internal organs, digestive structures are frequently preserved in Cambrian Lagerst\u00e4tten. However, the reasons for their fossilisation and their biological implications remain to be thoroughly explored. This is particularly true with arthropods \u2013 typically the most diverse fossilised organisms in Cambrian ecosystems \u2013 where digestive structures represent an as-yet underexploited alternative to appendage morphology for inferences on their biology. Here we describe the phosphatised digestive structures of three trilobite species from the Cambrian Weeks Formation Lagerst\u00e4tte (Utah). Their exquisite, three-dimensional preservation reveals unique details on trilobite internal anatomy, such as the position of the mouth and the absence of a differentiated crop. In addition, the presence of paired pygidial organs of an unknown function is reported for the first time. This exceptional material enables exploration of the relationships between gut phosphatisation and the biology of organisms. Indeed, soft-tissue preservation is unusual in these fossils as it is restricted to the digestive structures, which indicates that the gut played a central role in its own phosphatisation. We hypothesize that the gut provided a microenvironment where special conditions could develop and harboured a source of phosphorus. The fact that gut phosphatization has almost exclusively been observed in arthropods could be explained by their uncommon ability to store ions (including phosphorous) in their digestive tissues. However, in some specimens from the Weeks Formation, the phosphatisation extends to the entire digestive system, suggesting that trilobites might have had some biological particularities not observed in modern arthropods. We speculate that one of them might have been an increased capacity for ion storage in the gut tissues, related to the moulting of their heavily-mineralised carapace.", "keyphrases": ["gut phosphatisation", "trilobite", "utah", "anatomy", "digestive system"]}
{"id": "10.1098/rspb.2001.1639", "title": "Stable isotopes data (\u03b413C, \u03b415N) from the cave bear (Ursus spelaeus): a new approach to its palaeoenvironment and dormancy", "abstract": "Palaeoclimatic data that can be extracted from the isotopic signatures of \u03b413C and \u03b415N, which are found in fossil bone collagen, should be analysed according to the specific metabolism of each species. Although Ursus spelaeus is an extinct species, its metabolism is assimilated to current, closely related species of bear. In this study, bone collagen isotopic signatures (\u03b413C and \u03b415N) of cave bears from Late Pleistocene Alpine sites were compared to those that have already been documented. The \u03b413C signature did not seem to follow a systematic trend according to climatic conditions, probably as a consequence of the high variability present in the values of C3 plants, which were the basis of feeding. On the contrary, the \u03b415N signature displayed higher values in sites corresponding to colder periods in which the \u03b415N signature appeared to be dominated by the physiology of dormancy. Then, due to the reuse of urea in synthesizing amino acids, the \u03b415N signature systematically increased along with dormancy duration. This was related to the length of winter and, in turn, depended on climate.", "keyphrases": ["cave bear", "ursus spelaeus", "dormancy"]}
{"id": "10.1080/20555563.2019.1703167", "title": "Revisiting East\u2013West Skull Patterns and the Role of Random Factors in South America: Cranial Reconstruction and Morphometric Analysis of the Facial Skeleton from Cuncaicha Rockshelter (Southern Peru)", "abstract": "ABSTRACT The aim of this paper is to evaluate the craniometric affinities of the only Cuncaicha cranial specimen with other early, middle, and late Holocene South American samples. To do so, the skull was first reconstructed by using computer-aided techniques applied to several \u03bc-CT-scanned fragments. Linear measurements were calculated in the facial skeleton and compared to specimens from a previously available database. We conducted Principal Component and Discriminant Analysis, calculated Mahalanobis distances to evaluate the similarities of the Cuncaicha specimen with early/middle Holocene samples from South America, and estimated a \u0394 statistic for testing the neutral hypothesis among Peruvian samples. The results show that Cuncaicha presents shape similarities with Lagoa Santa and Lauricocha, mostly in masticatory and respiratory components. Finally, directional selection explains most of the diversification of Peruvian populations. We discuss our results in the context of migratory pathways, as well as the evolutionary processes behind human diversification in the Americas.", "keyphrases": ["south america", "facial skeleton", "evolutionary process"]}
{"id": "10.1002/ajpa.1330930305", "title": "New early eocene anaptomorphine primate (Omomyidae) from the Washakie Basin, Wyoming, with comments on the phylogeny and paleobiology of anaptomorphines.", "abstract": "Recent paleontological collecting in the Washakie Basin, southcentral Wyoming, has resulted in the recovery of over 100 specimens of omomyid primates from the lower Eocene Wasatch Formation. Much of what is known about anaptomorphine omomyids is based upon work in the Bighorn and Wind River Basins of Wyoming. This new sample documents greater taxonomic diversity of omomyids during the early Eocene and contributes to our understanding of the phylogeny and adaptations of some of these earliest North American primates. A new middle Wasatchian (Lysitean) anaptomorphine, Anemorhysis savagei, n. sp., is structurally intermediate between Teilhardina americana and other species of Anemorhysis and may be a sister group of other Anemorhysis and Trogolemur. Body size estimates for Anemorhysis, Tetonoides, Trogolemur, and Teilhardina americana indicate that these animals were extremely small, probably less than 50 grams. Analysis of relative shearing potential of lower molars of these taxa indicates that some were primarily insectivorous, some primarily frugivorous, and some may have been more mixed feeders. Anaptomorphines did not develop the extremes of molar specialization for frugivory or insectivory seen in extant prosimians. Incisor enlargement does not appear to be associated with specialization in either fruits or insects but may have been an adaptation for specialized grooming or food manipulation.", "keyphrases": ["anaptomorphine", "washakie basin", "phylogeny"]}
{"id": "paleo.003748", "title": "Devonian Pearls and Ammonoid-Endoparasite Co-Evolution", "abstract": "Raised shell projections on the inner shell walls that form pits on the internal moulds of Devonian ammonoids have been known for several decades. New specimens from Morocco reveal novel details of these structures; most, if not all, of which consist of a capsule of ammonoid shell that covers tiny tubes attached to the outer (= lateral or ventral) shell wall from the inside. In accordance with comparable Recent occurrences of similar structures in molluscs, we use the term \u201cpearls\u201d for these structures and the pits they form on the internal moulds. The nature of these encapsulated tubes is described and discussed. Because of the presence of these tubes inside the pearls, pearl arrangement, and their similarity to Recent mollusc occurrences, the tubes are interpreted as traces of parasitoses. The pearls and pits were grouped into five types based on differences in morphology, size, and arrangement. Then, having used these traits to perform a simple cladistic analysis, the resulting cladogram was compared to the phylogeny of ammonoids. Based on this comparison, it appears likely that the parasites underwent a co-evolution with the ammonoids, which lasted 10 to 15 Ma. Patterns of evolutionary events include co-speciation, \u201cdrowning on arrival\u201d (end of parasite lineage near base of a new host clade), and \u201cmissing the boat\u201d (parasite lineage does not adapt to a new host clade, thus not evolving a new parasite clade). Because of the lack of fossilised soft tissue, only speculations can be made about the systematic affiliation of the parasites, their life-cycle, infection strategy, and ecological framework. Some co-occurring bivalves also have pits reminiscent to structures caused by trematodes in Recent forms. Based on the available information, the tubes are interpreted as artefacts of trematode infestations, which, if correct, would extend the fossil record of parasitic trematodes into the Early Devonian.", "keyphrases": ["pearl", "co-evolution", "parasite", "ammonite"]}
{"id": "10.1029/2010PA002081", "title": "Black shale deposition, atmospheric CO2 drawdown, and cooling during the Cenomanian-Turonian Oceanic Anoxic Event", "abstract": "[1]\u00a0Oceanic Anoxic Event 2 (OAE2), spanning the Cenomanian-Turonian boundary (CTB), represents one of the largest perturbations in the global carbon cycle in the last 100 Myr. The \u03b413Ccarb, \u03b413Corg, and \u03b418O chemostratigraphy of a black shale\u2013bearing CTB succession in the Vocontian Basin of France is described and correlated at high resolution to the European CTB reference section at Eastbourne, England, and to successions in Germany, the equatorial and midlatitude proto-North Atlantic, and the U.S. Western Interior Seaway (WIS). \u039413C (offset between \u03b413Ccarb and \u03b413Corg) is shown to be a good pCO2 proxy that is consistent with pCO2 records obtained using biomarker \u03b413C data from Atlantic black shales and leaf stomata data from WIS sections. Boreal chalk \u03b418O records show sea surface temperature (SST) changes that closely follow the \u039413C pCO2 proxy and confirm TEX86 results from deep ocean sites. Rising pCO2 and SST during the Late Cenomanian is attributed to volcanic degassing; pCO2 and SST maxima occurred at the onset of black shale deposition, followed by falling pCO2 and cooling due to carbon sequestration by marine organic productivity and preservation, and increased silicate weathering. A marked pCO2 minimum (\u223c25% fall) occurred with a SST minimum (Plenus Cold Event) showing >4\u00b0C of cooling in \u223c40 kyr. Renewed increases in pCO2, SST, and \u03b413C during latest Cenomanian black shale deposition suggest that a continuing volcanogenic CO2 flux overrode further drawdown effects. Maximum pCO2 and SST followed the end of OAE2, associated with a falling nutrient supply during the Early Turonian eustatic highstand.", "keyphrases": ["oceanic anoxic event", "plenus cold event", "black shale deposition", "organic carbon"]}
{"id": "10.1002/spp2.1244", "title": "First monodontid cetacean (Odontoceti, Delphinoidea) from the early Pliocene of the north\u2010western Pacific Ocean", "abstract": "Monodontids are among the most enigmatic cetaceans due to their scarcity in the fossil record. Previously, except for fragmentary materials, only three skulls were known from the pre\u2010Pleistocene; these came from the east coast of the Pacific and both east and west coasts of the Atlantic. Haborodelphis japonicus, a new early Pliocene monodontid cetacean from the north\u2010west Pacific, significantly expands the palaeobiogeographical extent of the ancestral monodontids. The new taxon differs from all other monodontids in the following character states: the robust postorbital process for the skull size; the short rostrum relative to the whole skull length; the anterior dorsal infraorbital foramina posterior to the level of the antorbital notch; the premaxillary foramen on the level of the antorbital notch; the dorsally gently convex premaxillary sac fossa; the palatines wedged into the maxillae anteriorly on the midline; and the presence of the clearly excavated posteromedial sulcus. Monodontids were almost certainly adapted to warmer waters than their living counterparts Delphinapterus leucas and Monodon monoceros, both of which are confined to the high latitudes of the northern hemisphere. However, closer inspection (based mainly on fossil invertebrates) of the palaeoenvironments from which the monodontid fossils were produced, reveals that they may have preferred cooler conditions than previously thought. Due to the short climatic fluctuation cycles during the Pliocene in the northern hemisphere, and the increase of heterogeneity and regionality of the coastal environments, the dating of layers within a formation is critical for understanding palaeoenvironment in terms of the sea surface temperatures.", "keyphrases": ["cetacean", "pliocene", "haborodelphis japonicus"]}
{"id": "10.1666/10015.1", "title": "Fossil evidence for low gas exchange capacities for Early Cretaceous angiosperm leaves", "abstract": "Abstract The photosynthetic gas exchange capacities of early angiosperms remain enigmatic. Nevertheless, many hypotheses about the causes of early angiosperm success and how angiosperms influenced Mesozoic ecosystem function hinge on understanding the maximum capacity for early angiosperm metabolism. We applied structure-functional analyses of leaf veins and stomatal pore geometry to determine the hydraulic and diffusive gas exchange capacities of Early Cretaceous fossil leaves. All of the late Aptian\u2013early Albian angiosperms measured possessed low vein density and low maximal stomatal pore area, indicating low leaf gas exchange capacities in comparison to modern ecologically dominant angiosperms. Gas exchange capacities for Early Cretaceous angiosperms were equivalent or lower than ferns and gymnosperms. Fossil leaf taxa from Aptian to Paleocene sediments previously identified as putative stem-lineages to Austrobaileyales and Chloranthales had the same gas exchange capacities and possibly leaf water relations of their living relatives. Our results provide fossil evidence for the hypothesis that high leaf gas exchange capacity is a derived feature of later angiosperm evolution. In addition, the leaf gas exchange functions of austrobaileyoid and chloranthoid fossils support the hypothesis that comparative research on the biology of living basal angiosperm lineages reveals genuine signals of Early Cretaceous angiosperm ecophysiology.", "keyphrases": ["gas exchange capacity", "gymnosperm", "fossil evidence"]}
{"id": "paleo.009393", "title": "Cartilaginous Epiphyses in Extant Archosaurs and Their Implications for Reconstructing Limb Function in Dinosaurs", "abstract": "Extinct archosaurs, including many non-avian dinosaurs, exhibit relatively simply shaped condylar regions in their appendicular bones, suggesting potentially large amounts of unpreserved epiphyseal (articular) cartilage. This \u201clost anatomy\u201d is often underappreciated such that the ends of bones are typically considered to be the joint surfaces, potentially having a major impact on functional interpretation. Extant alligators and birds were used to establish an objective basis for inferences about cartilaginous articular structures in such extinct archosaur clades as non-avian dinosaurs. Limb elements of alligators, ostriches, and other birds were dissected, disarticulated, and defleshed. Lengths and condylar shapes of elements with intact epiphyses were measured. Limbs were subsequently completely skeletonized and the measurements repeated. Removal of cartilaginous condylar regions resulted in statistically significant changes in element length and condylar breadth. Moreover, there was marked loss of those cartilaginous structures responsible for joint architecture and congruence. Compared to alligators, birds showed less dramatic, but still significant changes. Condylar morphologies of dinosaur limb bones suggest that most non-coelurosaurian clades possessed large cartilaginous epiphyses that relied on the maintenance of vascular channels that are otherwise eliminated early in ontogeny in smaller-bodied tetrapods. A sensitivity analysis using cartilage correction factors (CCFs) obtained from extant taxa indicates that whereas the presence of cartilaginous epiphyses only moderately increases estimates of dinosaur height and speed, it has important implications for our ability to infer joint morphology, posture, and the complicated functional movements in the limbs of many extinct archosaurs. Evidence suggests that the sizes of sauropod epiphyseal cartilages surpassed those of alligators, which account for at least 10% of hindlimb length. These data suggest that large cartilaginous epiphyses were widely distributed among non-avian archosaurs and must be considered when making inferences about locomotor functional morphology in fossil taxa.", "keyphrases": ["archosaur", "cartilage", "joint surface", "cartilaginous epiphysis", "limb length"]}
{"id": "paleo.010963", "title": "Growth Dynamics of Australia's Polar Dinosaurs", "abstract": "Analysis of bone microstructure in ornithopod and theropod dinosaurs from Victoria, Australia, documents ontogenetic changes, providing insight into the dinosaurs' successful habitation of Cretaceous Antarctic environments. Woven-fibered bone tissue in the smallest specimens indicates rapid growth rates during early ontogeny. Later ontogeny is marked by parallel-fibered tissue, suggesting reduced growth rates approaching skeletal maturity. Bone microstructure similarities between the ornithopods and theropods, including the presence of LAGs in each group, suggest there is no osteohistologic evidence supporting the hypothesis that polar theropods hibernated seasonally. Results instead suggest high-latitude dinosaurs had growth trajectories similar to their lower-latitude relatives and thus, rapid early ontogenetic growth and the cyclical suspensions of growth inherent in the theropod and ornithopod lineages enabled them to successfully exploit polar regions.", "keyphrases": ["australia", "polar dinosaur", "bone microstructure", "high-latitude dinosaur", "growth mark"]}
{"id": "10.1002/ecy.1531", "title": "The functional extinction of Andean megafauna.", "abstract": "Controversy exists over the cause and timing of the extinction of the Pleistocene megafauna. In the tropical Andes, deglaciation and associated rapid climate change began ~8,000\u00a0years before human arrival, providing an opportunity to separate the effects of climate change from human hunting on megafaunal extinction. We present a paleoecological record spanning the last 25,000\u00a0years from Lake Pacucha, Peru (3,100\u00a0m elevation). Fossil pollen, charcoal, diatoms, and the dung fungus Sporormiella, chronicle a two-stage megaherbivore population collapse. Sporormiella abundance, the proxy for megafaunal presence, fell sharply at ~21,000\u00a0years ago, but rebounded prior to a permanent decline between ~16,800 and 15,800\u00a0years ago. This two-stage decline in megaherbivores resulted in a functional extinction by ~15,800\u00a0years ago, 3,000\u00a0years earlier than known human occupation of the high Andes. Declining\u00a0megaherbivore populations coincided with warm, wet intervals. Climatic instability and megafaunal population collapse triggered an ecological cascade that resulted in novel floral assemblages, and increases in woody species, fire frequency, and plant species that were sensitive to trampling. Our data revealed that Andean megafaunal populations collapsed due to positive feedbacks between habitat quality and climate change rather than human activity.", "keyphrases": ["functional extinction", "megafauna", "fire frequency"]}
{"id": "paleo.005233", "title": "A new Paleocene nyctitheriid insectivore from Inner Mongolia (China) and the origin of Asian nyctitheriids", "abstract": "Nyctitheriids are primitive insectivores that were relatively abundant and diverse in North America and Europe during the middle Paleocene through to the middle Oligocene. The nyctitheriids from Asia are poorly known and show several distinctive characters. Here we describe the late Paleocene Asionyctia guoi gen. et sp. nov., the first fairly well known Asian nyctitheriid, from the Subeng locality near the city of Erlianhot (Erenhot) in Inner Mongolia, China. Among its most conspicuous features are the paraconid positioned high on p4, the rather primitive morphology and size of p3, the premolariform P4/p4 and the transverse upper molars with a small, straight postcingulum. Except for the paraconid positioned high on p4, these combined features are also present in other Asian nyctitheriids, but absent in North American or European forms. We performed a cladistic analysis, based on a set of 20 dental characters, to resolve higher-level phylogenetic relations within Nyctitheriidae. The strict consensus tree groups all Asian forms in a single clade, for which we propose the rank of a subfamily and the name Asionyctiinae subfam. nov. Within Nyctitheriidae, a semimolariform P4/p4, as in Leptacodon tener, is considered primitive, and we consider the morphologically simplified P4/p4 of Asionyctiinae derived within Nyctitheriidae. Asionyctiinae can be derived from an American, primitive Leptacodon-like ancestor migrating into Asia, with the reduction of P4/p4 occurring on the Asian continent. Considering the derived morphology and the relatively high diversity of Asionyctiinae during the Asian late Paleocene, and the inferred conservative nature of the family Nyctitheriidae, we suggest an early Tiffanian time for the migration of nyctitheriids into Asia.", "keyphrases": ["paleocene", "insectivore", "asian nyctitheriid", "asionyctiinae"]}
{"id": "10.4202/app.00171.2015", "title": "Functional Morphology and Biomechanics of the Cynodont Trucidocynodon riograndensis from the Triassic of Southern Brazil: Pectoral Girdle and Forelimb", "abstract": "Non-mammalian cynodonts provide insights on several points about mammalian evolution, such as the postural change and locomotory advances within the group. Unfortunately, complete skeletons of Triassic cynodonts are rather uncommon and where more complete specimens are found they can offer a global vision on some traits not available from partial specimens. This is the case of the cynodont Trucidocynodon riograndensis, from the Triassic of Brazil, that has preserved its forelimbs providing some insights into locomotory properties. The movements between interclavicle and clavicle must have been limited, as such as those occurring between the latter and the scapulocoracoid although the long acromion process of this should have permitted a greater degree of freedom. Some of the more significant movements were those on the shoulder joint, in which the maximum adduction should have been ca. 35\u00b0 relative to the parasagittal plane and the greater abduction ca. 55\u00b0. The maximum adduction occurred when the humerus was in the more retracted position during stride and the variation in the adduction/abduction should have been significant to the limb posture during its recovery stroke. The long olecranon and the distal overlapping between radius and ulna suggest the predominance of simple flexion/extension on the forearm without significant pronation/supination. The poorly preserved hand suggests that Trucidocynodon could have evolved a slight semidigitigrad condition in its forelimbs. All these features give to this cynodont an important role in the evolution of the mammalian locomotory properties indicating that some features, such as the possibility of greater humeral adduction, evolved early in cynodont lineage.", "keyphrases": ["cynodont trucidocynodon riograndensis", "triassic", "forelimb"]}
{"id": "paleo.006890", "title": "Systematics and convergent evolution of multiple reef-associated Jurassic and Cretaceous crabs (Decapoda, Brachyura)", "abstract": "The Late Jurassic marks the first major radiation among true crabs (Brachyura) in reef environments, followed by another diversification in the midto Late Cretaceous in multiple habitats. We studied brachyuran carapaces from Mesozoic spongeand coralassociated limestones in Europe. Six new taxa are described: Late Jurassic Europrosopon gen. nov., Eodromites bernchrisdomiorum sp. nov., Prosopon josephcollinsi sp. nov., Tanidromites nightwishorum sp. nov., and T. weinschenki sp. nov.; and midCretaceous Eodromites cristinarobinsae sp. nov. Furthermore, we recognize four junior synonyms: Eodromites grandis (=E. guenteri), Tanidromites scheffnerae (=T. wysokaensis), and Europrosopon aculeatum (=E. verrucosum and E. barbulescuae). Five taxa are reassigned: Eodromites aequilatus to Tanidromites, Tanidromites rotundus to Eodromites, Nodoprosopon dzhafarberdensis to ?Abyssophthalmus, Nodoprosopon from Nodoprosopidae to Homolodromiidae, and Rathbunopon from Glaessneropsidae to Prosopidae. Several other taxa are redescribed. The latter reassignment indicates that Rathbunopon does not represent an example of extreme convergent evolution as implied previously. Conversely, the frontal structure consisting of a rostrum with two diverging spines and outer orbital spines appears a remarkable example of convergent evolution of the goniodromitid Navarradromites toward members of Homolodromiidae, for which this frontal structure is characteristic. Rostral spines represent another example of convergent evolution. Some specimens are extraordinary: A specimen of Abyssophthalmus cf. A. spinosus represents the largest complete reported Jurassic brachyuran thus far and one specimen of Planoprosopon aff. P. hystricosus bears one of the largest known parasitic isopod-induced swellings (ichnotaxon Kanthyloma crusta) relative to carapace size. Overall, our results indicate that biodiversity and convergent evolution in Mesozoic brachyurans remain understudied. KLOMPMAKER ET AL.: MESOZOIC REEF CRABS 2 Adi\u00ebl A. Klompmaker. Department of Museum Research and Collections & Alabama Museum of Natural History, The University of Alabama, Box 870340, Tuscaloosa, Alabama 35487, USA; Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, 1005 Valley Life Sciences Building #3140, Berkeley, California 94720, USA. adielklompmaker@gmail.com Natalia Starzyk. Institute of Systematics and Evolution of Animals, Polish Academy of Sciences, ul. S\u0142awkowska 17, 31-016 Krak\u00f3w, Poland. natalia_slaby@wp.pl Ren\u00e9 H.B. Fraaije. Oertijdmuseum, Bosscheweg 80, NL-5283 WB Boxtel, The Netherlands. info@oertijdmuseum.nl G\u00fcnter Schweigert. Staatliches Museum f\u00fcr Naturkunde, Rosenstein 1, 70191 Stuttgart, Germany. guenter.schweigert@smns-bw.de", "keyphrases": ["convergent evolution", "brachyura", "prosopidae"]}
{"id": "10.1073/pnas.1705378114", "title": "Mercury evidence for pulsed volcanism during the end-Triassic mass extinction", "abstract": "Significance The end of the Triassic Period (\u223c201.5 million years ago) witnessed one of the largest mass extinctions of animal life known from Earth history. This extinction is suggested to have coincided with and been caused by one of the largest known episodes of volcanic activity in Earth\u2019s history. This study examines mercury concentrations of sediments from around the world that record this extinction. Mercury is emitted in gaseous form during volcanism, and subsequently deposited in sediments. We find numerous pulsed elevations of mercury concentrations in end-Triassic sediments. These peaks show that the mass extinction coincided with large-scale, episodic, volcanism. Such episodic volcanism likely perturbed the global environment over a long period of time and strongly delayed ecological recovery. The Central Atlantic Magmatic Province (CAMP) has long been proposed as having a causal relationship with the end-Triassic extinction event (\u223c201.5 Ma). In North America and northern Africa, CAMP is preserved as multiple basaltic units interbedded with uppermost Triassic to lowermost Jurassic sediments. However, it has been unclear whether this apparent pulsing was a local feature, or if pulses in the intensity of CAMP volcanism characterized the emplacement of the province as a whole. Here, six geographically widespread Triassic\u2013Jurassic records, representing varied paleoenvironments, are analyzed for mercury (Hg) concentrations and Hg/total organic carbon (Hg/TOC) ratios. Volcanism is a major source of mercury to the modern environment. Clear increases in Hg and Hg/TOC are observed at the end-Triassic extinction horizon, confirming that a volcanically induced global Hg cycle perturbation occurred at that time. The established correlation between the extinction horizon and lowest CAMP basalts allows this sedimentary Hg excursion to be stratigraphically tied to a specific flood basalt unit, strengthening the case for volcanic Hg as the driver of sedimentary Hg/TOC spikes. Additional Hg/TOC peaks are also documented between the extinction horizon and the Triassic\u2013Jurassic boundary (separated by \u223c200 ky), supporting pulsatory intensity of CAMP volcanism across the entire province and providing direct evidence for episodic volatile release during the initial stages of CAMP emplacement. Pulsatory volcanism, and associated perturbations in the ocean\u2013atmosphere system, likely had profound implications for the rate and magnitude of the end-Triassic mass extinction and subsequent biotic recovery.", "keyphrases": ["volcanism", "end-triassic mass extinction", "mercury concentration", "province"]}
{"id": "10.1017/jpa.2017.54", "title": "Dental eruption sequence and hypsodonty index of a Pleistocene macraucheniid from the Brazilian Intertropical Region", "abstract": "Abstract. \n Litopterna is represented in the Pleistocene of the Brazilian Intertropical Region by a monospecific genus of Macraucheniidae, Xenorhinotherium. Although most of the knowledge about this family is derived from the dentition, some dental features still remain unknown. This study describes the eruption sequence of permanent dentition and classifies the hypsodonty status of X. bahiense. The specimens studied are from Toca dos Ossos, a limestone cave located in Bahia State. We perform qualitative macroscopic analysis to describe the eruption dental sequence. Additionally, we perform quantitative analysis to determine the hypsodonty index. The dental eruption sequence of the juvenile specimen is M1, M2, I1, I2, M3, I3, P1, P2, P3, and P4. In addition, the analysis of tooth wear in adult specimens provides similar results. The hypsodonty index assigns a mesodont tooth crown for X. bahiense. The dental eruption sequence is most similar to a rapid-growth extant mammal. Moreover, our results do not support afrotherian-like delayed dental eruption to Litopterna. The hypsodonty index can be related to data on vegetation of the Brazilian Intertropical Region and the shape of the premaxilla of X. bahiense, both of which suggest a browsing diet for this macraucheniid.", "keyphrases": ["hypsodonty index", "macraucheniid", "dental eruption sequence"]}
{"id": "paleo.006580", "title": "Testing for a facultative locomotor mode in the acquisition of archosaur bipedality", "abstract": "Bipedal locomotion is a defining characteristic of humans and birds and has a profound effect on how these groups interact with their environment. Results from extensive hominin research indicate that there exists an intermediate stage in hominin evolution\u2014facultative bipedality\u2014between obligate quadrupedality and obligate bipedality that uses both forms of locomotion. It is assumed that archosaur locomotor evolution followed this sequence of functional and hence character-state evolution. However, this assumption has never been tested in a broad phylogenetic context. We test whether facultative bipedality is a transitionary state of locomotor mode evolution in the most recent early archosaur phylogenies using maximum-likelihood ancestral state reconstructions for the first time. Across a total of seven independent transitions from quadrupedality to a state of obligate bipedality, we find that facultative bipedality exists as an intermediary mode only once, despite being acquired a total of 14 times. We also report more independent acquisitions of obligate bipedality in archosaurs than previously hypothesized, suggesting that locomotor mode is more evolutionarily fluid than expected and more readily experimented with in these reptiles.", "keyphrases": ["locomotor mode", "acquisition", "archosaur"]}
{"id": "10.3998/jar.0521004.0067.104", "title": "ON THE QUESTION OF SHORT-TERM NEANDERTHAL SITE OCCUPATIONS: Payre, France (MIS 8-7), and Taubach/Weimar, Germany (MIS 5)", "abstract": "We analyze and compare the evidence of human behavior from two Middle Paleolithic localities with short-term (seasonal) occupations: Payre in France (level F, correlated to MIS 8-7) and Taubach in Germany (correlated to MIS 5e). We focus on the lithic assemblages from these occupation levels. Our analysis takes the density of lithic material, technological choices, and the typological composition of the assemblages in the two localities into account. In light of previously published models, the results are partially consistent with various types of land-use as supported by analysis of the lithic assemblages. Our results confirm that Neanderthals were able to develop diverse behaviors in different locations. Although flexible and highly adaptable among the different seasons and landscapes of Western Europe, different types of short occupations may indicate the same kinds of technical and typological strategies.", "keyphrases": ["occupation", "payre", "mis", "germany"]}
{"id": "10.1080/02724634.1997.10010951", "title": "Redescription of the dentition of Grippia longirostris (Ichthyosauria) with a comparison with Utatsusaurus hataii", "abstract": "ABSTRACT Reexamination of the dentition of Grippia longirostris (Ichthyosauria) provides new information, and also reveals errors in the original descriptions. A dental groove is present in G. longirostris, with shallow sockets at the bottom; hence, the implantation is subthecodont, at least in the posterior part of the mandible. There are two rows of maxillary teeth as originally described, but it seems that the lingual row comprises replacement teeth for the labial row, and that each replacement tooth is positioned distolingual of its predecessor. The anterior teeth are not well preserved in any of the specimens. The posterior teeth are blunt but rarely spherical, and are small both absolutely and relative to the skull width. The dentition and the jaw structure suggest a wide range of prey items, rather than strict durophagy as previously proposed. The dentition of G. longirostris is similar to that of Utatsusaurus hataii in general tooth structure, tooth implantation and replacement, and in relative to...", "keyphrases": ["dentition", "ichthyosauria", "utatsusaurus hataii", "skull"]}
{"id": "10.3390/d15020233", "title": "Basal Anseriformes from the Early Paleogene of North America and Europe", "abstract": "We describe nearly complete skeletons of basal Anseriformes from the Latest Paleocene to the early Eocene of North America and Europe. Collectively, these birds appear to be representative of anseriforms near the divergence of Anhimae and Anseres, but their exact positions relative to these clades remains uncertain. A new family, Anachronornithidae nov. fam., is erected on the basis of one of these, Anachronornis anhimops nov. gen., nov. gen. et sp., to which the others cannot be confidently assigned. The new fossils augment a growing collection of early Pan-Anseriformes, which in their diversity do not paint an unambiguous picture of phylogeny or character state evolution on the path to or within crown-Anseriformes. Anachronornis nov. gen. is similar in some aspects of both cranial and postcranial anatomy to other well-represented early Paleogene Anseriformes and members of Anseres, such as Presbyornis Wetmore, 1926. However, it exhibits a more landfowl-like bill, like that of Anhimae and unlike the spatulate bill of Anseres. Additional specimens of similar basal Anseriformes of uncertain affinities from the early Eocene of North America and Europe further complicate interpretation of character state polarity due to the mosaicism of primitive and derived characters they exhibit.", "keyphrases": ["north america", "eocene", "basal anseriformes"]}
{"id": "10.1111/j.1469-7580.2006.00637.x", "title": "Endoscopic investigation of the internal organs of a 15th\u2010century child mummy from Yangju, Korea", "abstract": "Our previous reports on medieval mummies in Korea have provided information on their preservation status. Because invasive techniques cannot easily be applied when investigating such mummies, the need for non\u2010invasive techniques incurring minimal damage has increased among researchers. Therefore, we wished to confirm whether endoscopy, which has been used in non\u2010invasive and minimally invasive studies of mummies around the world, is an effective tool for study of Korean mummies as well. In conducting an endoscopic investigation on a 15th\u2010century child mummy, we found that well\u2010preserved internal organs remained within the thoracic, abdominal and cranial cavities. The internal organs \u2013 including the brain, spinal cord, lung, muscles, liver, heart, intestine, diaphragm and mesentery \u2013 were easily investigated by endoscopy. Even the stool of the mummy, which accidentally leaked into the abdominal cavity during an endoscopic biopsy, was clearly observed. In addition, unusual nodules were found on the surface of the intestines and liver. Our current study therefore showed that endoscopic observation could provide an invaluable tool for the palaeo\u2010pathological study of Korean mummies. This technique will continue to be used in the study of medieval mummy cases in the future.", "keyphrases": ["internal organ", "invasive technique", "endoscopic investigation"]}
{"id": "10.1080/02724634.2011.621797", "title": "Osteohistology of the Triassic Archosauromorphs Prolacerta, Proterosuchus, Euparkeria, and Erythrosuchus from the Karoo Basin of South Africa", "abstract": "ABSTRACT The South African non-archosauriform archosauromorph Prolacerta and the archosauriforms Proterosuchus, Erythrosuchus, and Euparkeria were important constituents of the Early to early Middle Triassic Karoo ecosystem following the end-Permian mass extinction. We present new data on the osteohistology of these stem archosaurs and provide insight into their paleobiology. Bone tissues of the Early Triassic Prolacerta contain a poorly defined fibro-lamellar complex, with parallelfibered bone in some regions, whereas the contemporaneous Proterosuchus exhibits rapidly forming uninterrupted fibrolamellar bone early in its ontogeny, which becomes slow forming lamellar-zonal bone with increasing age. The early Middle Triassic Erythrosuchus deposited highly vascularized, uninterrupted fibro-lamellar bone throughout ontogeny, whereas the growth of the contemporaneous Euparkeria was relatively slow and cyclical. When our data are combined with those of previous studies, preliminary results reveal that Early and Middle Triassic non-crown group archosauromorphs generally exhibit faster growth rates than many of those of the Late Triassic. Early rapid growth and rapid attainment of sexual maturity are consistent with life history expectations for taxa living in the unpredictable conditions following the end-Permian mass extinction. Further research with larger sample sizes will be required to determine the nature of the environmental pressures on these basal archosaurs.", "keyphrases": ["euparkeria", "erythrosuchus", "basal archosaur", "osteohistology"]}
{"id": "10.1073/pnas.1708023114", "title": "Heterochronic truncation of odontogenesis in theropod dinosaurs provides insight into the macroevolution of avian beaks", "abstract": "Significance We identified truncation of tooth development during postnatal ontogeny in two theropod dinosaurs, a caenagnathid oviraptorosaur and the Early Cretaceous bird Sapeornis. Developmental and paleontological evidence each suggests dental reduction and beak evolution are coupled, and a sequence of common morphologies is identified that characterizes the multiple transitions to toothless beaks in theropod dinosaurs and birds. Shifts toward earlier cessation of postnatal tooth development can be identified in fish, amphibians, and mammals that are edentulous as adults; therefore the identification of similar transitions in multiple Mesozoic theropod dinosaur lineages strongly implies that heterochronic truncation of odontogenesis played an important role in the macroevolution of beaks in modern birds. Beaks are innovative structures characterizing numerous tetrapod lineages, including birds, but little is known about how developmental processes influenced the macroevolution of these important structures. Here we provide evidence of ontogenetic vestigialization of alveoli in two lineages of theropod dinosaurs and show that these are transitional phenotypes in the evolution of beaks. One of the smallest known caenagnathid oviraptorosaurs and a small specimen of the Early Cretaceous bird Sapeornis both possess shallow, empty vestiges of dentary alveoli. In both individuals, the system of vestiges connects via foramina with a dorsally closed canal homologous to alveoli. Similar morphologies are present in Limusaurus, a beaked theropod that becomes edentulous during ontogeny; and an analysis of neontological and paleontological evidence shows that ontogenetic reduction of the dentition is a relatively common phenomenon in vertebrate evolution. Based on these lines of evidence, we propose that progressively earlier postnatal and embryonic truncation of odontogenesis corresponds with expansion of rostral keratin associated with the caruncle, and these progenesis and peramorphosis heterochronies combine to drive the evolution of edentulous beaks in nonavian theropods and birds. Following initial apomorphic expansion of rostral keratinized epithelia in perinatal toothed theropods, beaks appear to inhibit odontogenesis as they grow postnatally, resulting in a sequence of common morphologies. This sequence is shifted earlier in development through phylogeny until dentition is absent at hatching, and odontogenesis is inhibited by beak formation in ovo.", "keyphrases": ["odontogenesis", "theropod dinosaur", "ontogeny", "dentition", "heterochronic truncation"]}
{"id": "10.1073/pnas.1822038116", "title": "Opinion: To curate the molecular past, museums need a carefully considered set of best practices", "abstract": "Biomolecular research has sparked a methodological revolution in the field of anthropology, and museums are now faced with the curatorial challenge of conserving and evaluating materials for these new methods. Since 2010, hundreds of genome-wide datasets from ancient human samples have been published, and thousands more have been generated; doubling the amount of data in the field of paleogenomics now requires less time than the publication of a single article (1). Technological advances in laboratory and bioinformatic approaches have also led to a new era in paleomicrobiology, in which entire ancient microbial communities can be recovered from various substrates, such as calcified dental calculus (2). Increasingly, large-scale datasets for other biomolecules, such as proteins and metabolites, are generated and integrated into multi-omic understandings of the human past (2).\n\n\n\nFig. 1. \nMuseum collections staff stand among the anthropological collections at the Smithsonian's National Museum of Natural History. Museums are responsible for preserving collections and the information they contain for future generations. But in recent years, they\u2019ve been given the increasingly challenging task of curating and conserving biomolecular data. Image credit: Chip Clark (Smithsonian Institution, Washington, DC).\n\n\n\nAnthropological collections are important for science and society for reasons that include their potential applications for biomolecular research (3, 4). Ethical issues are central in the changing circumstances for ancient biomolecular information. Potential negative impacts on indigenous communities (such as when paleogenomic studies contradict traditional histories and undermine territorial or repatriation claims) have magnified the importance of community-based practices (5). Competition among ancient-DNA laboratories for museum samples has been likened to \u201cthe Wild West\u201d (6), and more strictly regulating access to samples has been advocated to prevent \u201choarding\u201d (7). As stewards of collections that contain ancient biomolecules (e.g., isotopes, proteins, DNA, and metabolites), museums play a critical role among stakeholders in biomolecular research and should \u2026 \n\n[\u21b5][1]2To whom correspondence may be addressed. Email: sholtss{at}si.edu or courtney.hofman{at}ou.edu.\n\n [1]: #xref-corresp-1-1", "keyphrases": ["past", "museum", "practice", "ethical issue", "issue"]}
{"id": "paleo.000074", "title": "A large aberrant stem ichthyosauriform indicating early rise and demise of ichthyosauromorphs in the wake of the end-Permian extinction", "abstract": "Contrary to the fast radiation of most metazoans after the end-Permian mass extinction, it is believed that early marine reptiles evolved slowly during the same time interval. However, emerging discoveries of Early Triassic marine reptiles are questioning this traditional view. Here we present an aberrant basal ichthyosauriform with a hitherto unknown body design that suggests a fast radiation of early marine reptiles. The new species is larger than coeval marine reptiles and has an extremely small head and a long tail without a fluke. Its heavily-built body bears flattened and overlapping gastral elements reminiscent of hupehsuchians. A phylogenetic analysis places the new species at the base of ichthyosauriforms, as the sister taxon of Cartorhynchus with which it shares a short snout with rostrally extended nasals. It now appears that ichthyosauriforms evolved rapidly within the first one million years of their evolution, in the Spathian (Early Triassic), and their true diversity has yet to be fully uncovered. Early ichthyosauromorphs quickly became extinct near the Early-Middle Triassic boundary, during the last large environmental perturbation after the end-Permian extinction involving redox fluctuations, sea level changes and volcanism. Marine reptile faunas shifted from ichthyosauromorph-dominated to sauropterygian-dominated composition after the perturbation.", "keyphrases": ["end-permian extinction", "marine reptile", "early triassic", "phylogenetic analysis", "ichthyopterygia"]}
{"id": "paleo.000181", "title": "First early Eocene lizards from Spain and a study of the compositional changes between late Mesozoic and early Cenozoic Iberian lizard assemblages", "abstract": "Lizard and amphisbaenian fossil material is described for the first time from early Eocene localities in Spain, more specifically from Catalonia (north-eastern Iberian Peninsula). Material is fragmentary and scarce, but diagnostic enough to provide a first approach to the composition of lizard assemblages. The following taxa are recorded: Geiseltaliellus and a second indeterminate pleurodont iguanid; an agamid similar to \"Tinosaurus\"; an indeterminate gekkotan; a scincoid, possibly scincid lizard; a lacertid similar to Dormaalisaurus; an indeterminate amphisbaenian; a glyptosaurin glyptosaurine (cf. Placosaurus); an indeterminate anguine; and, finally, an indeterminate \"necrosaur.\" The studied localities range from the MP8+9 to the MP10, and thus complement the only previously known lizard locality of the Iberian early Eocene, the Portuguese locality of Silveirinha, which corresponds to the MP7. An analysis of the composition of these new assemblages suggests a great amount of homogeneity through the different levels of the early Eocene, and also between Iberian and contemporaneous assemblages from the rest of Europe. The lack of an Iberian Paleocene record for lizards strengthens the importance of the study of early Eocene assemblages because these are the only ones available for comparison with Cretaceous associations, providing critical information on the changes in composition between Mesozoic and early Cenozoic lizard faunas related to the K/Pg extinction event.", "keyphrases": ["spain", "lizard assemblage", "europe"]}
{"id": "10.1029/90JB01916", "title": "Revised and synthetic apparent polar wander paths of the African, Eurasian, North American and Indian Plates, and true polar wander since 200 Ma", "abstract": "We have reviewed paleomagnetic data available for the Eurasian, African, North American and Indian plates over the last 200 Ma. Selection criteria are those generally accepted, with an emphasis on evidence for lack of remagnetization, accurate dating and proper structural analysis. This results in 23, 35, 51 and 2 poles for Eurasia, Africa, North America and India, respectively. We believe that this limited set of higher quality data is more likely to reveal key features of apparent polar wander (APW) paths than averaging of larger data sets involving less stringent selection criteria. We propose and describe revised APW paths, but more importantly, we next use relative motion models to transfer all data in a common reference frame. We find good agreement between transferred data, when they are averaged separately for each plate in independent 20-Ma windows. This is a check on consistency of paleomagnetic data, kinematic models, and of the geocentric dipole hypothesis. Transferred data from all plates are averaged in 20-Ma windows to generate synthetic APW paths for all plates studied. These synthetic paths are in agreement with the original (revised) APW paths that use only data from a single plate. Moreover, both geographic and time resolution are improved (spatial confidence intervals are of the order of 5\u00b0). The synthetic paths display interesting features, such as a previously ill-recognized APW loop for Eurasia. Paleomagnetic and hotspot APW are next compared, and a determination of true polar wander (TPW) is derived. We find significant TPW, amounting to over 20\u00b0 in the last 200 Ma. TPW appears to be episodic, with a standstill between 180 and 110 Ma. There is general agreement with a previous study of Livermore et al. (1984). The TPW standstill appears to correlate with a time of decreasing reversal frequency, ending with the Cretaceous Long Normal Superchron. Other periods of fast TPW would seem to correspond to increasing reversal frequency. However, it is suggested that the major TPW hairpin at 50 Ma might correspond to the collision of India with Eurasia. Tentative correlations with core or mantle indicators can be understood as a result of couplings between the core, mantle and lithosphere, we believe primarily related to episodic evolution of the D\u2033 layer.", "keyphrases": ["eurasian", "true polar wander", "northern alaska"]}
{"id": "10.1017/S0022336000027529", "title": "Dianulites Eichwald, 1829: An unusual Ordovician bryozoan with a high-magnesium calcite skeleton", "abstract": "The \u2018granular\u2019 wall microstructure of the Ordovician stenolaemate bryozoan Dianulites Eichwald, 1829, has been studied using ultrathin sections, scanning electron microscopy (SEM), analytical SEM, and cathodoluminescence. The timing of recrystallization and the presence of microdolomite inclusions in the skeletal walls implies that the original skeleton consisted of high-magnesium calcite (HMC). Although found in some modern cheilostomes, HMC has not been recorded in living stenolaemate bryozoans, but appears to have also been present in Nicholsonella and a few other Ordovician genera traditionally assigned to the trepostomes or cystoporates. The Russian type species of Dianulites, D. fastigiatus Eichwald, 1829, is revised and recorded for the first time in North America from the Fillmore Formation (Lower Ordovician) of Utah. Unusually among bryozoans, D. fastigiatus has turbinate, cone- or horn-shaped colonies, straight to slightly curved, with zooids opening on the flat, broad end of the cone; the sides of the cone comprise calcified exterior walls. This growth-form resembles some solitary rugose corals and other benthic animals thought to have lived with all but their tops buried in soft sediment. Such an interpretation is supported in Dianulites by the scarcity of epibionts on the exterior walls of the cone and by the occurrence of specimens comprising stacks of subcolonies, suggesting periods of partial burial of the living tissues by sediment.", "keyphrases": ["ordovician", "bryozoan", "nicholsonella", "low-mg calcite"]}
{"id": "10.1080/02724634.2018.1555164", "title": "Tarsal morphology and locomotor adaptation of some late middle Eocene caviomorph rodents from Peruvian Amazonia reveal early ecological diversity", "abstract": "ABSTRACT In rodents, and other vertebrates in general, the morphology of tarsal bones, especially the astragalus and calcaneus, has been shown to be tightly linked to locomotor movements. As a result, it has been used to infer locomotor behaviors in extinct species. Recent expeditions in Peruvian Amazonia have led to the discovery of the oldest caviomorph rodent fossils in South America, including two calcanei and one astragalus. The morphologies of these three tarsal bones are described in detail and compared with other extant and extinct caviomorphs. In order to assess and infer the locomotor behaviors of these rodents, linear measurements were taken on these tarsal bones and analyzed via multivariate analyses based on a previously assembled large data set. Both qualitative and quantitative analyses consistently suggest that the osteological adaptations of the astragalus enhance movements for climbing, those of one calcaneus rather enhance movements indicating terrestrial and partly fossorial lifestyle, whereas the other calcaneus may have belonged to a generalist form with a tendency toward a semiaquatic lifestyle. These results fit well with the associated paleoenvironments and hint at ecological diversity early in caviomorph history.", "keyphrases": ["rodent", "peruvian amazonia", "ecological diversity"]}
{"id": "paleo.007851", "title": "First discovery of the soft\u2010body imprint of an Oligocene fossil squid indicates its piscivorous diet", "abstract": "The first well-preserved soft-body imprint of a fossil squid was discovered from the Lower Oligocene of the Krasnodar region, Russia. The squid is perfectly preserved, with many details of its body available for study, such as imprints of eyes and head, a pair of statoliths, jaws, and stomach contents. Statoliths of this squid are the first finds of in situ statoliths in fossil non-belemnoid coleoids, and their shape is characteristic of the genus Loligo (family Loliginidae). Although some Mesozoic coleoids were previously classified as teuthids, these finds remain controversial and the squid described herein is the first unquestionable representative of fossil Teuthida known to date. It should be noted that the squid is preserved not due to phosphatization, which is typical for fossil coleoids, but by pyritization and carbonization. Numerous fish remains in the stomach contents of the squid indicate its piscivorous diet. A small cutlassfish Anenchelum angustum, which was buried together with the squid and whose bones are located near the squid's jaws, sheds light on the circumstances of the death of this animal. Most likely, the squid suffocated in the anoxic bottom waters, where it drowned along with its last prey (distraction sinking).", "keyphrases": ["imprint", "oligocene", "piscivorous diet"]}
{"id": "10.1515/geoca-2016-0030", "title": "Diversity and distribution patterns of the Oligocene and Miocene decapod crustaceans (Crustacea: Malacostraca) of the Western and Central Paratethys", "abstract": "Abstract Decapod associations have been significant components of marine habitats throughout the Cenozoic when the major diversification of the group occurred. In this respect, the circum-Mediterranean area is of particular interest due to its complex palaeogeographic history. During the Oligo-Miocene, it was divided in two major areas, Mediterranean and Paratethys. Decapod crustaceans from the Paratethys Sea have been reported in the literature since the 19th century, but only recent research advances allow evaluation of the diversity and distribution patterns of the group. Altogether 176 species-level taxa have been identified from the Oligocene and Miocene of the Western and Central Paratethys. Using the three-dimensional NMDS analysis, the composition of decapod crustacean faunas of the Paratethys shows significant differences through time. The Ottnangian and Karpatian decapod associations were similar to each other both taxonomically and in the mode of preservation, and they differed taxonomically from the Badenian ones. The Early Badenian assemblages also differed taxonomically from the Late Badenian ones. The time factor, including speciation, immigration from other provinces and/or (local or global) extinction, can explain temporal differences among assemblages within the same environment. High decapod diversity during the Badenian was correlated with the presence of reefal settings. The Badenian was the time with the highest decapod diversity, which can, however, be a consequence of undersampling of other time slices. Whereas the Ottnangian and Karpatian decapod assemblages are preserved virtually exclusively in the siliciclastic \u201cSchlier\u201d-type facies that originated in non-reefal offshore environments, carbonate sedimentation and the presence of reefal environments during the Badenian in the Central Paratethys promoted thriving of more diverse reef-associated assemblages. In general, Paratethyan decapods exhibited homogeneous distribution during the Oligo-Miocene among the basins in the Paratethys. Based on the co-occurrence of certain decapod species, migration between the Paratethys and the North Sea during the Early Miocene probably occurred via the Rhine Graben. At larger spatial scales, our results suggest that the circum-Mediterranean marine decapod taxa migrated in an easterly direction during the Oligocene and/or Miocene, establishing present-day decapod communities in the Indo-West Pacific.", "keyphrases": ["distribution pattern", "oligocene", "decapod crustacean"]}
{"id": "10.1017/S0094837300003778", "title": "A factor analytic description of the Phanerozoic marine fossil record", "abstract": "Data on numbers of marine families within 91 metazoan classes known from the Phanerozoic fossil record are analyzed. The distribution of the 2800 fossil families among the classes is very uneven, with most belonging to a small minority of classes. Similarly, the stratigraphic distribution of the classes is very uneven, with most first appearing early in the Paleozoic and with many of the smaller classes becoming extinct before the end of that era. However, despite this unevenness, a Q-mode factor analysis indicates that the structure of these data is rather simple. Only three factors are needed to account for more than 90% of the data. These factors are interpreted as reflecting the three great \u201cevolutionary faunas\u201d of the Phanerozoic marine record: a trilobite-dominated Cambrian fauna, a brachiopod-dominated later Paleozoic fauna, and a mollusc-dominated Mesozoic-Cenozoic, or \u201cmodern,\u201d fauna. Lesser factors relate to slow taxonomic turnover within the major faunas through time and to unique aspects of particular taxa and times. Each of the three major faunas seems to have its own characteristic diversity so that its expansion or contraction appears as being intimately associated with a particular phase in the history of total marine diversity. The Cambrian fauna expands rapidly during the Early Cambrian radiations and maintains dominance during the Middle to Late Cambrian \u201cequilibrium.\u201d The Paleozoic fauna then ascends to dominance during the Ordovician radiations, which increase diversity dramatically; this new fauna then maintains dominance throughout the long interval of apparent equilibrium that lasts until the end of the Paleozoic Era. The modern fauna, which slowly increases in importance during the Paleozoic Era, quickly rises to dominance with the Late Permian extinctions and maintains that status during the general rise in diversity to the apparent maximum in the Neogene. The increase in diversity associated with the expansion of each new fauna appears to coincide with an approximately exponential decline of the previously dominant fauna, suggesting possible displacement of each evolutionary fauna by its successor.", "keyphrases": ["phanerozoic", "class", "paleozoic", "evolutionary faunas", "sepkoski"]}
{"id": "paleo.002890", "title": "Multibody dynamics model of head and neck function in Allosaurus (Dinosauria, Theropoda)", "abstract": "We present a multibody dynamics model of the feeding apparatus of the large Jurassic theropod dinosaur Allosaurus that enables testing of hypotheses about the animal's feeding behavior and about how anatomical parameters influence function. We created CT-and anatomical-inference-based models of bone, soft tissue, and air spaces which we use to provide inertial properties for musculoskeletal dynamics. Estimates of bone density have a surprisingly large effect on head inertial properties, and trachea diameter strongly affects moments of inertia of neck segments for dorsoventral movements. The ventrally-placed insertion of m. longissimus capitis superficialis in Allosaurus imparted over twice the ventroflexive accelerations of a proxy control insertion lateral to the occipital condyle, the latter being its position in nearly all other theropods. A feeding style that involved defleshing a carcass by avian-raptor-like retraction of the head in Allosaurus is more probable than is lateroflexive shake-feeding, such as that seen in crocodilians and inferred for tyrannosaurids.", "keyphrases": ["head", "allosaurus", "acceleration", "multibody dynamic model"]}
{"id": "paleo.001310", "title": "A \u2018giant\u2019 purgatoriid (Plesiadapiformes) from the Paleocene of Montana, USA: mosaic evolution in the earliest primates", "abstract": "Ursolestes perpetior gen. et sp. nov. is a large purgatoriid plesiadapiform primate from the middle/late Puercan (earliest Paleocene) Simpson Quarry, Montana, USA. It differs from Purgatorius Van Valen and Sloan, 1965, the only other known purgatoriid and the oldest discovered primate, in its substantially larger body size as inferred from the dimensions of the known parts of its dentition, while resembling Purgatorius in possessing a large lower canine, unreduced p1, and in the upper molars, a protocone twist and weakly developed postprotocone fold; moreover, the m3 of U. perpetior possesses an expanded, plesiadapiform\u2010like posterior lobe of the talonid that supports the hypoconulid. The large lower canine and the greater development of trenchant molar crests suggest that U. perpetior was more insectivorous, differing appreciably from the omnivorous niche long hypothesized for Purgatorius and purportedly marking the insectivore\u2013primate transition. Hence, U. perpetior adds significant new knowledge regarding the breadth of the adaptive zone occupied by purgatoriids in their position at the very beginnings of primate evolution.", "keyphrases": ["purgatoriid", "paleocene", "primate", "dimension"]}
{"id": "10.1017/pab.2017.8", "title": "Temporal dynamics of encrusting communities during the Late Devonian: a case study from the Central Devonian Field, Russia", "abstract": "Abstract. \n In this study we focused on the dynamics of encrusting assemblages preserved on brachiopod hosts collected from upper Frasnian and lower Famennian deposits of the Central Devonian Field, Russia. Because the encrusted brachiopods come from deposits bracketing the Frasnian/Famennian (F/F) boundary, the results also shed some light on ecological differences in encrusting communities before and after the Frasnian\u2014Famennian (F-F) event. To explore the diversity dynamics of encrusting assemblages, we analyzed more than 1300 brachiopod valves (substrates) from two localities. Taxon accumulation plots and shareholder quorumsubsampling (SQS) routines indicated that a reasonably small sample of brachiopod host valves (n=50) is sufficient to capture themajority of the encrusting genera recorded at a given site. The richness of encrusters per substrate declined simultaneously with the number of encrusting taxa in the lower Famennian, accompanied by a decrease in epibiont abundance, with a comparable decrease in mean encrustation intensity (percentage of bioclasts encrusted by one or more epibionts). Epibiont abundance and occupancy roughlymirror each other. Strikingly, few ecological characteristics are correlated with substrate size, possibly reflecting random settlement of larvae. Evenness, which is negatively correlated with substrate size, shows greater within-stage variability among samples than between Frasnian and Famennian intervals and may indicate the instability of early Famennian biocenoses following the faunal turnover. The occurrence distribution of encrusters points to nonrandomassociations and exclusions among several encrusting taxa. However, abundance and occupancy of microconchids remained relatively stable throughout the sampled time interval. The notable decline in abundance (\u223c60%) and relatively minor decline in diversity (\u223c30%) suggest jointly that encrusting communities experienced ecological collapse rather than a major mass extinction event. The differences between the upper Frasnian and lower Famennian encrusting assemblages may thus record a turnover associated with the F-F event.", "keyphrases": ["dynamic", "encruster", "central devonian field"]}
{"id": "10.2110/palo.2011.p11-112r", "title": "A SNAPSHOT OF AN EARLY PERMIAN ECOSYSTEM PRESERVED BY EXPLOSIVE VOLCANISM: NEW RESULTS FROM THE CHEMNITZ PETRIFIED FOREST, GERMANY", "abstract": "ABSTRACT A recently excavated locality in the Chemnitz Petrified Forest, lower Permian in age and occurring within the Leukersdorf Formation of the Chemnitz Basin, Germany, provides evidence for an outstanding fossil assemblage buried in situ by pyroclastics. The environment is interpreted as forested lowland that sheltered a dense hygrophilous vegetation of ferns, sphenophytes, and gymnosperms, as well as a diverse fauna of reptiles, amphibians, arthropods, and gastropods. A detailed measured section of the outcrop documents the early volcanic history of the Chemnitz fossil forest, including a paleosol that shows the root systems of Psaronius tree ferns, Arthropitys calamitaleans, and Medullosa and Cordaixylon gymnosperms in the same horizon. Fifty-three trunks are still standing upright and rooted at their place of growth, providing evidence that the top of the paleosol was the land surface on which the forest grew, thereby offering insights into the original plant community structure and density. Taphonomic analysis of both the petrified and adpression-fossil assemblages enable us to reconstruct the direction, estimate the violence and extent of the volcanic events, and their effects on the entire ecosystem. A complete dataset of three-dimensional coordinates resulting from three and one-half years of continuing excavation and study permits the recognition of organ connections and results in the first reconstructions of the excavation site, the floral elements, and the plant community as a whole.", "keyphrases": ["ecosystem", "chemnitz petrified forest", "germany"]}
{"id": "10.1080/02724634.2017.1343250", "title": "The Second Titanosaurian (Dinosauria: Sauropoda) from the Middle Cretaceous Galula Formation, Southwestern Tanzania, with Remarks on African Titanosaurian Diversity", "abstract": "ABSTRACT \n The paleobiogeographic significance of continental Africa during the middle and Late Cretaceous is not well understood, in part due to incomplete sampling from large portions of the landmass during these intervals. Intensified field efforts in the Galula Formation exposed in southwestern Tanzania have revealed a diverse vertebrate fauna, including the novel titanosaurian Shingopana songwensis, gen. et sp. nov., described herein. Based on a left angular, cervical vertebrae, cervical and dorsal ribs, a left humerus, and a partial left pubis, Shingopana exhibits morphology indicating affinities with the Late Cretaceous aeolosaurine titanosaurians of South America. The bulbous expansion of the cervical vertebral neural spine is similar to the condition in Bonitasaura salgadoi, Overosaurus paradasorum, and Trigonosaurus pricei. The dorsal ribs of Shingopana also present proximal anterior and posterior flanges that previously were proposed to be unique to Overosaurus. Furthermore, Shingopana is diagnosed by a divided spinoprezygapophyseal lamina in the middle-to-posterior cervical vertebrae. Parsimony and both uncalibrated and tip-dated Bayesian phylogenetic approaches support Shingopana as the first African titanosaurian that is closely related to aeolosaurines. Comparisons with other African titanosaurians, such as the co-occurring Rukwatitan bisepultus and geographically proximate Malawisaurus dixeyi, suggest that southern African forms represent diverse taxa rather than forming a monophyletic group. Moreover, southern African forms exhibit stronger affinities with South American clades than with representative northern African form, suggesting that tectonically driven separation of the two landmasses may have influenced the development of progressively isolated southern African faunas throughout the Cretaceous.", "keyphrases": ["titanosaurian", "southwestern tanzania", "aeolosaurine"]}
{"id": "10.1098/rspb.2009.1339", "title": "Anthropoid versus strepsirhine status of the African Eocene primates Algeripithecus and Azibius: craniodental evidence", "abstract": "Recent fossil discoveries have demonstrated that Africa and Asia were epicentres for the origin and/or early diversification of the major living primate lineages, including both anthropoids (monkeys, apes and humans) and crown strepsirhine primates (lemurs, lorises and galagos). Competing hypotheses favouring either an African or Asian origin for anthropoids rank among the most hotly contested issues in paleoprimatology. The Afrocentric model for anthropoid origins rests heavily on the >45 Myr old fossil Algeripithecus minutus from Algeria, which is widely acknowledged to be one of the oldest known anthropoids. However, the phylogenetic position of Algeripithecus with respect to other primates has been tenuous because of the highly fragmentary fossils that have documented this primate until now. Recently recovered and more nearly complete fossils of Algeripithecus and contemporaneous relatives reveal that they are not anthropoids. New data support the idea that Algeripithecus and its sister genus Azibius are the earliest offshoots of an Afro\u2013Arabian strepsirhine clade that embraces extant toothcombed primates and their fossil relatives. Azibius exhibits anatomical evidence for nocturnality. Algeripithecus has a long, thin and forwardly inclined lower canine alveolus, a feature that is entirely compatible with the long and procumbent lower canine included in the toothcomb of crown strepsirhines. These results strengthen an ancient African origin for crown strepsirhines and, in turn, strongly challenge the role of Africa as the ancestral homeland for anthropoids.", "keyphrases": ["algeripithecus", "azibius", "anthropoid"]}
{"id": "paleo.004332", "title": "Abrupt changes in distance between succeeding septa at the hatching time in modern coleoids Sepiella japonica and Spirula spirula", "abstract": "Analyses of distances between succeeding septa throughout ontogeny of modern coleoids Sepiella japonica and Spirula spirula reveal that the first several septa (until ca. 6th-8th septa in Sepiella japonica and until ca. 2nd-3rd septa in Spirula spirula) have relatively larger septal distances than the following septa and then the distances between succeeding septa abruptly decrease at the time of hatching for both species, which are known from previous rearing observations and stable isotopic analyses. If this relationship holds in fossil cephalopods preserving internal shells, their paleo-hatching timings could be reconstructed through the ontogenetic analyses of their septal distances.", "keyphrases": ["coleoid sepiella japonica", "spirula spirula", "septum", "ontogenetic analysis"]}
{"id": "10.5194/cp-9-1053-2013", "title": "Heinrich event 4 characterized by terrestrial proxies in southwestern Europe", "abstract": "Abstract. Heinrich event 4 (H4) is well documented in the North Atlantic Ocean as a cooling event that occurred between 39 and 40 Ka. Deep-sea cores around the Iberian Peninsula coastline have been analysed to characterize the H4 event, but there are no data on the terrestrial response to this event. Here we present for the first time an analysis of terrestrial proxies for characterizing the H4 event, using the small-vertebrate assemblage (comprising small mammals, squamates and amphibians) from Terrassa Riera dels Canyars, an archaeo-palaeontological deposit located on the seaboard of the northeastern Iberian Peninsula. This assemblage shows that the H4 event is characterized in northeastern Iberia by harsher and drier terrestrial conditions than today. Our results were compared with other proxies such as pollen, charcoal, phytolith, avifauna and large-mammal data available for this site, as well as with the general H4 event fluctuations and with other sites where H4 and the previous and subsequent Heinrich events (H5 and H3) have been detected in the Mediterranean and Atlantic regions of the Iberian Peninsula. We conclude that the terrestrial proxies follow the same patterns as the climatic and environmental conditions detected by the deep-sea cores at the Iberian margins.", "keyphrases": ["terrestrial proxy", "iberian peninsula", "environmental condition", "heinrich event"]}
{"id": "paleo.003096", "title": "Common species link global ecosystems to climate change: dynamical evidence in the planktonic fossil record", "abstract": "Common species shape the world around us, and changes in their commonness signify large-scale shifts in ecosystem structure and function. However, our understanding of long-term ecosystem response to environmental forcing in the deep past is centred on species richness, neglecting the disproportional impact of common species. Here, we use common and widespread species of planktonic foraminifera in deep-sea sediments to track changes in observed global occupancy (proportion of sampled sites at which a species is present and observed) through the turbulent climatic history of the last 65 Myr. Our approach is sensitive to relative changes in global abundance of the species set and robust to factors that bias richness estimators. Using three independent methods for detecting causality, we show that the observed global occupancy of planktonic foraminifera has been dynamically coupled to past oceanographic changes captured in deep-ocean temperature reconstructions. The causal inference does not imply a direct mechanism, but is consistent with an indirect, time-delayed causal linkage. Given the strong quantitative evidence that a dynamical coupling exists, we hypothesize that mixotrophy (symbiont hosting) may be an ecological factor linking the global abundance of planktonic foraminifera to long-term climate changes via the relative extent of oligotrophic oceans.", "keyphrases": ["climate change", "proportion", "common specie"]}
{"id": "paleo.003600", "title": "REMOTE SENSING APPLIED TO PALEONTOLOGY: EXPLORATION OF UPPER CRETACEOUS SEDIMENTS IN KAZAKHSTAN FOR POTENTIAL FOSSIL SITES", "abstract": "Here we show that low-cost analysis of satellite image data (derived from Landsat ETM+) can be used efficiently for the 'remote prospecting' of a large field area, in this test case in Kazakhstan. By developing a spectral library to characterize the sedimentary profiles in our field area, we outline a simple method that can be used to quickly identify the locations of potentially fossiliferous strata that can subsequently be prospected first-hand by paleontologists on the ground. We have successfully tested this remote approach to search for fossils in the Lower Syrdarya Uplift in southern Kazakhstan -an area that encompasses more than 17,000 square kilometers. As image capture and analysis technologies develop, remote prospecting (sensing) applications are likely to become more and more prevalent in paleontology, especially in the development of remote field areas.", "keyphrases": ["sensing", "paleontology", "kazakhstan"]}
{"id": "paleo.005995", "title": "A new ichnogenus for Teredolites longissimus Kelly and Bromley", "abstract": "Ichnotaxobases that provide internally consistent classification schemes for trace fossils such as burrows and borings include general form, branching, orientation, ornamentation, internal structure and fill, and boundaries. Substrate is a poor ichnotaxobase but it has been widely used for some ichnogenera, most notably the clavate (clubshaped) borings commonly produced by bivalves. The ichnogenus Teredolites Leymerie includes only two ichnospecies, both limited to xylic (woody) substrates; Teredolites clavatus Leymerie, the type species; and Teredolites longissimus Kelly and Bromley. Teredolites clavatus are club-shaped and short, whereas T. longissimus are long and straight to sinuous to worm-like. Although both are (commonly) bivalve borings in wood substrates, they are morphologically highly dissimilar. Teredolites longissimus Kelly and Bromley is made the type ichnospecies of Apectoichnus igen. nov. herein. Apectoichnus includes elongate borings, commonly circular in section, smooth-sided, sinuous to contorted and intertwined, and with or without a calcareous lining; they are found in wood.", "keyphrases": ["teredolite", "kelly", "wood"]}
{"id": "10.1073/pnas.1107450108", "title": "Strong reproductive isolation between humans and Neanderthals inferred from observed patterns of introgression", "abstract": "Recent studies have revealed that 2\u20133% of the genome of non-Africans might come from Neanderthals, suggesting a more complex scenario of modern human evolution than previously anticipated. In this paper, we use a model of admixture during a spatial expansion to study the hybridization of Neanderthals with modern humans during their spread out of Africa. We find that observed low levels of Neanderthal ancestry in Eurasians are compatible with a very low rate of interbreeding (<2%), potentially attributable to a very strong avoidance of interspecific matings, a low fitness of hybrids, or both. These results suggesting the presence of very effective barriers to gene flow between the two species are robust to uncertainties about the exact demography of the Paleolithic populations, and they are also found to be compatible with the observed lack of mtDNA introgression. Our model additionally suggests that similarly low levels of introgression in Europe and Asia may result from distinct admixture events having occurred beyond the Middle East, after the split of Europeans and Asians. This hypothesis could be tested because it predicts that different components of Neanderthal ancestry should be present in Europeans and in Asians.", "keyphrases": ["neanderthals", "introgression", "hybridization"]}
{"id": "10.1098/rspb.2017.1979", "title": "Long-term archives reveal shifting extinction selectivity in China's postglacial mammal fauna", "abstract": "Ecosystems have been modified by human activities for millennia, and insights about ecology and extinction risk based only on recent data are likely to be both incomplete and biased. We synthesize multiple long-term archives (over 250 archaeological and palaeontological sites dating from the early Holocene to the Ming Dynasty and over 4400 historical records) to reconstruct the spatio-temporal dynamics of Holocene\u2013modern range change across China, a megadiverse country experiencing extensive current-day biodiversity loss, for 34 mammal species over three successive postglacial time intervals. Our combined zooarchaeological, palaeontological, historical and current-day datasets reveal that both phylogenetic and spatial patterns of extinction selectivity have varied through time in China, probably in response both to cumulative anthropogenic impacts (an \u2018extinction filter\u2019 associated with vulnerable species and accessible landscapes being affected earlier by human activities) and also to quantitative and qualitative changes in regional pressures. China has experienced few postglacial global species-level mammal extinctions, and most species retain over 50% of their maximum estimated Holocene range despite millennia of increasing regional human pressures, suggesting that the potential still exists for successful species conservation and ecosystem restoration. Data from long-term archives also demonstrate that herbivores have experienced more historical extinctions in China, and carnivores have until recently displayed greater resilience. Accurate assessment of patterns of biodiversity loss and the likely predictive power of current-day correlates of faunal vulnerability and resilience is dependent upon novel perspectives provided by long-term archives.", "keyphrases": ["extinction selectivity", "china", "holocene range", "long-term archive"]}
{"id": "paleo.002541", "title": "Parasitic gastropod bioerosion trace fossil on Cenomanian oysters from Le Mans, France and its ichnologic and taphonomic context.", "abstract": "We describe and name Loxolenichnus stellatocinctus Breton and Wisshak igen. et isp. nov., a bioerosion trace fossil on an Upper Cenomanian oyster from Le Mans (France). This trace is attributed here to a parasitic gastropod. The characteristics of this ichnospecies are a combination of one or several, vertical or oblique, complete penetrations, and an asymmetrical attachment etching (fixichnion) with a diagnostic set of stellate grooves increasingly distinct towards the margin of the trace. By including two former Oichnus ichnospecies, Loxolenichnus halo comb. nov. and Loxolenichnus taddei comb. nov., Oichnus, is now constrained to pure predation traces (praedichnia). The numerous oysters collected from the Marnes \u00e0 Pycnodonte biauriculata Formation show associated epibionts and encrusters as well as borers and scrapers. Encrusters comprise 24 taxa while bioerosion trace fossils comprise 17 ichnotaxa ranging from very rare (Gnathichnus and Entobia ichnofacies are represented on the shellgrounds, presumably alternatingly.", "keyphrases": ["gastropod", "bioerosion trace fossil", "oyster"]}
{"id": "paleo.011645", "title": "The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile \u2013 Marine sources and diagenetic effects", "abstract": "Seabird excrements (guano) have been preserved in the arid climate of Northern Chile since at least the Pliocene. The deposits of marine organic material in coastal areas potentially open a window into the present and past composition of the coastal ocean and its food web. We use the stable isotope composition of nitrogen and carbon as well as element contents to compare the principal prey of the birds, the Peruvian anchovy, with the composition of modern guano. We also investigate the impact of diagenetic changes on the isotopic composition and elemental contents of the pure ornithogenic sediments, starting with modern stratified deposits and extending to fossil guano. Where possible, 14C systematics is used for age information. The nitrogen and carbon isotopic composition of the marine prey (Peruvian anchovy) of the birds is complex as it shows strong systematic variations with latitude. The detailed study of a modern profile that represents a few years of guano deposition up to present reveals systematic changes in nitrogen and carbon isotopic composition towards heavier values that increase with age, i.e. depth. Only the uppermost, youngest layers of modern guano show compositional affinity to the prey of the birds. In the profile, the simultaneous loss of nitrogen and carbon occurs by degassing, and non-volatile elements like phosphorous and calcium are passively enriched in the residual guano. Fossil guano deposits are very low in nitrogen and low in carbon contents, and show very heavy nitrogen isotopic compositions. One result of the study is that the use of guano for tracing nitrogen and carbon isotopic and elemental composition in the marine food web of the birds is restricted to fresh material. Despite systematic changes during diagenesis, there is little promise to retrieve reliable values of marine nitrogen and carbon signatures from older guano. However, the changes in isotopic composition from primary marine nitrogen isotopic signatures towards very heavy values generate a compositionally unique material. These compositions trace the presence of guano in natural ecosystems and its use as fertilizer in present and past agriculture.", "keyphrases": ["stable isotope composition", "nitrogen", "guano", "northern chile"]}
{"id": "10.1029/2000PA000502", "title": "Variability of the western Mediterranean Sea surface temperature during the last 25,000 years and its connection with the Northern Hemisphere climatic changes", "abstract": "Sea surface temperature (SST) profiles over the last 25 kyr derived from alkenone measurements are studied in four cores from a W-E latitudinal transect encompassing the Gulf of Cadiz (Atlantic Ocean), the Alboran Sea, and the southern Tyrrhenian Sea (western Mediterranean). The results document the sensitivity of the Mediterranean region to the short climatic changes of the North Atlantic Ocean, particularly those involving the latitudinal position of the polar front. The amplitude of the SST oscillations increases toward the Tyrrhenian Sea, indicating an amplification effect of the Atlantic signal by the climatic regime of the Mediterranean region. All studied cores show a shorter cooling phase (700 years) for the Younger Dryas (YD) than that observed in the North Atlantic region (1200 years). This time diachroneity is related to an intra-YD climatic change documented in the European continent. Minor oscillations in the southward displacement of the North Atlantic polar front may also have driven this early warming in the studied area. During the Holocene a regional diachroneity propagating west to east is observed for the SST maxima, 11.5\u201310.2 kyr B.P. in the Gulf of Cadiz, 10\u20139 kyr B.P. in the Alboran Sea, and 8.9\u20138.4 kyr B.P. in the Thyrrenian Sea. A general cooling trend from these SST maxima to present day is observed during this stage, which is marked by short cooling oscillations with a periodicity of 730\u00b140 years and its harmonics.", "keyphrases": ["mediterranean", "climatic change", "variability"]}
{"id": "paleo.006088", "title": "Biomechanical analyses of Cambrian euarthropod limbs reveal their effectiveness in mastication and durophagy", "abstract": "Durophagy arose in the Cambrian and greatly influenced the diversification of biomineralized defensive structures throughout the Phanerozoic. Spinose gnathobases on protopodites of Cambrian euarthropod limbs are considered key innovations for shell-crushing, yet few studies have demonstrated their effectiveness with biomechanical models. Here we present finite-element analysis models of two Cambrian trilobites with prominent gnathobases\u2014Redlichia rex and Olenoides serratus\u2014and compare these to the protopodites of the Cambrian euarthropod Sidneyia inexpectans and the modern American horseshoe crab, Limulus polyphemus. Results show that L. polyphemus, S. inexpectans and R. rex have broadly similar microstrain patterns, reflecting effective durophagous abilities. Conversely, low microstrain values across the O. serratus protopodite suggest that the elongate gnathobasic spines transferred minimal strain, implying that this species was less well-adapted to masticate hard prey. These results confirm that Cambrian euarthropods with transversely elongate protopodites bearing short, robust gnathobasic spines were likely durophages. Comparatively, taxa with shorter protopodites armed with long spines, such as O. serratus, were more likely restricted to a soft food diet. The prevalence of Cambrian gnathobase-bearing euarthropods and their various feeding specializations may have accelerated the development of complex trophic relationships within early animal ecosystems, especially the \u2018arms race' between predators and biomineralized prey.", "keyphrases": ["cambrian euarthropod limb", "effectiveness", "durophagy", "trilobite"]}
{"id": "10.12789/geocanj.2013.40.008", "title": "Great Canadian Lagerst\u00e4tten 4. The Devonian Miguasha Biota (Qu\u00e9bec): UNESCO World Heritage Site and a Time Capsule in the Early History of Vertebrates", "abstract": "Over the past 170 years, the Late Devonian Miguasha biota from eastern Canada has yielded a diverse aquatic assemblage including 20 species of lower vertebrates (anaspids, osteostracans, placoderms, acanthodians, actinopterygians and sarcopterygians), a more limited invertebrate assemblage, and a continental component including plants, scorpions and millipedes. Originally interpreted as a freshwater lacustrine environment, recent paleontological, taphonomic, sedimentological and geochemical evidence corroborates a brackish estuarine setting. Over 18,000 fish specimens have been recovered showing various modes of fossilization, including uncompressed material and soft-tissue preservation. Most vertebrates are known from numerous, complete, articulated specimens. Exceptionally well-preserved larval and juvenile specimens have been identified for 14 out of the 20 species of fishes, allowing growth studies. Numerous horizons within the Escuminac Formation are now interpreted as either\u00a0 Konservat\u2013\u00a0 or\u00a0 Konzentrat\u2013Lagerstatten . SOMMAIRE Au cours des 170 dernieres annees, le biote du Devonien superieur de Miguasha de l\u2019Est du Canada a fourni un assemblage aquatique diversifie, comprenant 20 especes de vertebres inferieurs (anaspides, osteostraces, placodermes, acanthodiens, actinopterygiens et sarcopterygiens) et un assemblage peu diversifie d\u2019invertebres ainsi qu\u2019une composante continentale, representee par des plantes, des scorpions et des mille-pattes. A l\u2019origine interprete comme un milieu lacustre d\u2019eau douce, les dernieres preuves paleontologiques, taphonomiques, sedimentologiques et geochimiques confirment un environnement saum\u00e2tre rappelant celui d\u2019un estuaire. Plus de 18,000 fossiles de poissons ont ete decouverts montrant differents etats de conservation, notamment en trois dimensions et la preservation de tissus mous. La plupart des vertebres sont connus par de nombreux specimens complets et articules. Des specimens de larves et de juveniles, exceptionnellement bien conserves, ont ete identifiees pour 14 des 20 especes de poissons permettant des etudes detaillees de leur croissance. De nombreux horizons au sein de la Formation d\u2019Escuminac sont interpretes soit comme des\u00a0 Konservat\u2013\u00a0 ou\u00a0 Konzentrat\u2013Lagerstatten .", "keyphrases": ["devonian miguasha biota", "vertebrate", "canada", "escuminac formation"]}
{"id": "paleo.001876", "title": "Elevated Extinction Rates as a Trigger for Diversification Rate Shifts: Early Amniotes as a Case Study", "abstract": "Tree shape analyses are frequently used to infer the location of shifts in diversification rate within the Tree of Life. Many studies have supported a causal relationship between shifts and temporally coincident events such as the evolution of \u201ckey innovations\u201d. However, the evidence for such relationships is circumstantial. We investigated patterns of diversification during the early evolution of Amniota from the Carboniferous to the Triassic, subjecting a new supertree to analyses of tree balance in order to infer the timing and location of diversification shifts. We investigated how uneven origination and extinction rates drive diversification shifts, and use two case studies (herbivory and an aquatic lifestyle) to examine whether shifts tend to be contemporaneous with evolutionary novelties. Shifts within amniotes tend to occur during periods of elevated extinction, with mass extinctions coinciding with numerous and larger shifts. Diversification shifts occurring in clades that possess evolutionary innovations do not coincide temporally with the appearance of those innovations, but are instead deferred to periods of high extinction rate. We suggest such innovations did not cause increases in the rate of cladogenesis, but allowed clades to survive extinction events. We highlight the importance of examining general patterns of diversification before interpreting specific shifts.", "keyphrases": ["amniote", "case study", "extinction event"]}
{"id": "10.1017/S0016774600000986", "title": "From river valley to estuary: the evolution of the Rhine mouth in the early to middle Holocene (western Netherlands, Rhine-Meuse delta)", "abstract": "Abstract The aim of this paper is to reconstruct the evolution of the early to middle Holocene Rhine-Meuse river mouths in the western Netherlands and to understand the observed spatial and temporal changes in facies. This is achieved by constructing three delta wide cross-sections using a newly accumulated database with thousands of core descriptions and cone penetration test results, together with a large set of pollen/diatom analyses and OSL/14C-dates. Most of the studied deposits accumulated in the fluvial-to-marine transition zone, a highly complex area due to the interaction of terrestrial and marine processes. Understanding how the facies change within this zone, is necessary to make correct palaeogeographic interpretations. We find a well preserved early to middle Holocene coastal prism resting on lowstand valley floors. Aggradation started after 9 ka cal BP as a result of rapid sea-level rise. Around 8 ka most parts of the study area were permanently flooded and under tidal influence. After 8 ka a bay-head delta was formed near Delft, meaning that little sand could reach the North Sea. Several subsequent avulsions resulted in a shift from the constantly retreating Rhine river mouth to the north. When after 6.5 ka the most northerly river course was formed (Oude Rijn), the central part of the palaeovalley was quickly transgressed and transformed into a large tidal basin. Shortly before 6 ka retrogradation of the coastline halted and tidal inlets began to close, marking the end of the early-middle Holocene transgression. This paper describes the transition from a fluvial valley to an estuary in unprecedented detail and enables more precise palaeo-reconstructions, evaluation of relative importance of fluvial and coastal processes in rapid transgressed river mouths, and more accurate sediment-budget calculations. The described and well illustrated (changes in) facies are coupled to lithogenetic units. This will aid detailed palaeogeographic interpretations from sedimentary successions, not only in the Netherlands, but also in other estuarine and deltaic regions.", "keyphrases": ["valley", "middle holocene", "western netherlands"]}
{"id": "10.1111/j.1502-3931.2012.00314.x", "title": "A taphonomic approach to the genetic interpretation of clypeasteroid accumulations from the Miocene of Tarragona, NE Spain", "abstract": "Belaustegui, Z., Nebelsick, J.H., Gibert, J.M. de, Domenech, R. & Martinell, J. 2012: A taphonomic approach to the genetic interpretation of clypeasteroid accumulations from the Miocene of Tarragona, NE Spain. Lethaia, Vol. 45, pp. 548\u2013565. \n \n \n \nClypeasteroid accumulations are common in Cenozoic shallow marine sediments, particularly in the Neogene, as they are also in analogue modern environments. In this article, four clypeasteroid accumulations from Miocene (Serravallian) shallow marine carbonates of the El Camp de Tarragona Basin (NE Spain) are studied. Two of them are dominated by flat-shaped Parascutella, whereas the other two consist exclusively of bell-shaped Clypeaster. The combination of the taphonomic analysis of the tests, the palaeoecological and taphonomic information provided by the associated fossils, and the stratigraphical and sedimentological context of each one of these beds allows interpreting them as autochthonous/parautochthonous accumulations resulting from in situ reworking in moderate energy settings, except for one that constitutes a true sand dollar coquina deposited by a storm event. This contribution explores the potential of thorough taphonomic analysis of marine invertebrate skeletal concentrations and substantiates the importance of clypeasteroid echinoids as producers of shell beds in the Neogene. \u25a1Clypeasteroids, Echinoids, Miocene, Taphonomy, Tarragona.", "keyphrases": ["genetic interpretation", "clypeasteroid accumulation", "miocene", "echinoid"]}
{"id": "paleo.000989", "title": "The ontogeny of cinctans (stem\u2010group Echinodermata) as revealed by a new genus, GraciaCystis, from the middle Cambrian of Spain", "abstract": "Abstract: A new cinctan echinoderm, Graciacystis ambigua gen. et sp. nov. from Cambrian Series 3 rocks of Spain, is described based on more than 100 articulated specimens that range from 6 to 14.5\u2003mm in thecal length. This material shows that Graciacystis ambigua, while plastic in thecal shape, is highly conservative in its thecal construction, with a fixed number of marginal plates and very limited addition of plates in the stele and ventral membrane through ontogeny. Ventral swellings on marginal elements are absent from the smallest specimens and become gradually more marked during growth. A cladistic analysis shows Graciacystis to be a basal cinctan, more derived than Sotocinctus and the Trochocystitidae and as sister group to a large clade formed by Sucocystidae\u2003+\u2003Gyrocystidae. The determinate growth pattern seen in Graciacystis seems to be the general pattern for all cinctans.", "keyphrases": ["ontogeny", "cinctan", "graciacystis"]}
{"id": "paleo.008678", "title": "A NEW RECONSTRUCTION OF ONYCHOSELACHE TRAQUAIRI, COMMENTS ON EARLY CHONDRICHTHYAN PECTORAL GIRDLES AND HYBODONTIFORM PHYLOGENY", "abstract": "Abstract:\u2002 A new, third, specimen of Onychoselache traquairi from the Vis\u00e9an (Holkerian) of Scotland allows a significant revision of the anatomy of this stem\u2010group elasmobranch. This first report of material from the Mumbie Quarry exposure of the Glencartholm fish beds presents a new reconstruction of Onychoselache showing broad\u2010based cephalic and nuchal spines, and exceptionally large pectoral fins. Details of the jaws, braincase and postcranial skeleton demonstrate that Onychoselache is a well\u2010characterized member of the Hybodontiformes. Comparisons of the pectoral skeleton with other early chondrichthyan examples, including new material of Tristychius arcuatus and Plesioselachus macracanthus, highlight a range of early chondrichthyan conditions that are incorporated into a revised hybodontiform phylogeny. Close resemblance between Onychoselache and Mesozoic and late Palaeozoic hybodonts implies that these clades diverged within the Carboniferous and Permian. Major differences between Onychoselache and the coeval Tristychius (a modified reconstruction of which is included) indicate that the Neoselachii\u2010Hybodontiformes split is probably Late Devonian, consistent with records of isolated teeth. The pectoral fins of Onychoselache, while unique among Palaeozoic forms, resemble those of Recent bamboo and epaulette sharks (Orectolobiformes). The functional corollary of this convergence is that Onychoselache represents an instance of a non\u2010tetrapod early vertebrate with a near\u2010walking gait.", "keyphrases": ["new reconstruction", "onychoselache traquairi", "hybodontiform phylogeny", "mesozoic"]}
{"id": "10.1371/journal.pone.0003703", "title": "Phylotyping and Functional Analysis of Two Ancient Human Microbiomes", "abstract": "Background The Human Microbiome Project (HMP) is one of the U.S. National Institutes of Health Roadmap for Medical Research. Primary interests of the HMP include the distinctiveness of different gut microbiomes, the factors influencing microbiome diversity, and the functional redundancies of the members of human microbiotas. In this present work, we contribute to these interests by characterizing two extinct human microbiotas. Methodology/Principal Findings We examine two paleofecal samples originating from cave deposits in Durango Mexico and dating to approximately 1300 years ago. Contamination control is a serious issue in ancient DNA research; we use a novel approach to control contamination. After we determined that each sample originated from a different human, we generated 45 thousand shotgun DNA sequencing reads. The phylotyping and functional analysis of these reads reveals a signature consistent with the modern gut ecology. Interestingly, inter-individual variability for phenotypes but not functional pathways was observed. The two ancient samples have more similar functional profiles to each other than to a recently published profile for modern humans. This similarity could not be explained by a chance sampling of the databases. Conclusions/Significance We conduct a phylotyping and functional analysis of ancient human microbiomes, while providing novel methods to control for DNA contamination and novel hypotheses about past microbiome biogeography. We postulate that natural selection has more of an influence on microbiome functional profiles than it does on the species represented in the microbial ecology. We propose that human microbiomes were more geographically structured during pre-Columbian times than today.", "keyphrases": ["functional analysis", "modern human", "phylotyping"]}
{"id": "10.1080/08120090902806347", "title": "Age constraints on Oligocene sedimentation in the Torquay Basin, southeastern Australia", "abstract": "The Otway, Gippsland and central coast basins (including the Torquay Basin, Sorrento Graben and Port Phillip Basin) preserve one of the most complete records of Mesozoic and Cenozoic sedimentation in southern Australia. However, robust age constraints on sedimentation are scarce. Strontium isotope analysis of calcitic bioclasts from the Jan Juc Marl of the Torquay Group, Torquay Basin, gives a range of possible ages between 24.2 and 27.9 Ma for the Jan Juc Marl, and an age of 24.24 Ma (+1.3 Ma, \u22121.2 Ma) for the base of the Point Addis Limestone. These data demonstrate that the Jan Juc Marl and the lower Point Addis Limestone are age-equivalent facies representing deep- and shallow-water sedimentation, respectively. 40Ar/39Ar whole-rock analysis of the underlying Angahook Formation basalt of the Demons Bluff Group gives an eruption age of 28.7 \u00b1 0.2 Ma. The upper boundary of the Angahook Formation is a subaerial exposure surface and paleoshore platform over which younger marine sediment onlapped during subsequent marine transgression. These new age constraints provide an improved age datum, of around 28.7 Ma, for the base of the Janjukian Stage. This age is very close to the European Rupelian\u2013Chattian boundary, which is the accepted boundary between the Early and Late Oligocene with an estimated age of 28.4 Ma.", "keyphrases": ["sedimentation", "torquay basin", "late oligocene"]}
{"id": "10.1111/j.1469-185X.1994.tb01273.x", "title": "ALTERNATION OF GENERATIONS IN LAND PLANTS: NEW PHYLOGENETIC AND PALAEOBOTANICAL EVIDENCE", "abstract": "Current ideas on the evolution of alternation of generations in land plants are reviewed in the context of important recent advances in plant systematics and the discovery of remarkable new palaeobotanical evidence on early embryophyte life cycles. An overview of relationships in major groups of green plants is presented together with a brief review of the early fossil record as a prelude to discussing hypotheses of life cycle evolution. Recent discoveries of life cycles in the early fossil record are described and assessed. The newly discovered gametophyte and sporophyte associations are based on exceptionally well\u2010preserved material from the Rhynie Chert, Scotland (Middle Devonian: 380\u2013408 Myr) and compression fossils from other Devonian localities. These data document diplobiontic life cycles in plants at the \u2018protracheophyte\u2019 and early tracheophyte level of organization. Furthermore, the early fossils have a more or less isomorphic alternation of generations, a striking departure from life cycles in extant embryophytes. This unexpected similarity between gametophyte and sporophyte calls for a cautious approach in identifying ploidy level in early groups. Viewed in a systematic context, the neontological and palaeontological data contribute towards the formulation of a coherent hypothesis of life cycle evolution in major, early embryophyte groups. Evidence from extant groups strongly supports a single direct origin of the diplobiontic life cycles of land plants from haploid, haplobiontic life cycles in ancestral \u2018charophycean algae\u2019. The interest of the new palaeobotanical data lies in its relevance to life cycle evolution at the restricted level of vascular plants rather than at the more general level of embryophytes (vascular plants plus \u2018bryophytes\u2019). The occurrence of morphologically complex, axial gametophytes in early vascular plants is consistent with the moss sister\u2010group proposed in some cladistic analyses. Similarities of moss gametophytes to fossils in the vascular plant stem\u2010group are discussed, and it is argued that the late appearance of mosses in the macrofossil record may be due to the problem of recognizing stem\u2010group taxa. The new palaeobotanical evidence conflicts with previous hypotheses based on extant groups that interpret morphological simplicity as the plesiomorphic condition in the gametophytes of vascular plants. These new data indicate that a significant elaboration of both gametophyte and sporophyte occurred early in the tracheophyte lineage, and that the gametophytes of extant \u2018pteridophytes\u2019 are highly reduced compared to those of some of the earliest \u2018protracheophytes\u2019. Vestiges of this early morphological complexity may remain in the gametophytes of some extant groups such as Lycopodiaceae.", "keyphrases": ["land plant", "palaeobotanical evidence", "gametophyte"]}
{"id": "paleo.002688", "title": "Congruence, fossils and the evolutionary tree of rodents and lagomorphs", "abstract": "Given an evolutionary process, we expect distinct categories of heritable data, sampled in ever larger amounts, to converge on a single tree of historical relationships. We tested this assertion by undertaking phylogenetic analyses of a new morphology-DNA dataset for mammals, focusing on Glires and including the oldest known skeletons of geomyoid and Ischyromys rodents. Our results support geomyoids in the mouse-related clade (Myomorpha) and a ricochetal locomotor pattern for the common ancestor of geomyoid rodents. They also support Ischyromys in the squirrel-related clade (Sciuromorpha) and the evolution of sciurids and Aplodontia from extinct, \u2018protrogomorph\u2019-grade rodents. Moreover, ever larger samples of characters from our dataset increased congruence with an independent, well-corroborated tree. Addition of morphology from fossils increased congruence to a greater extent than addition of morphology from extant taxa, consistent with fossils' temporal proximity to the common ancestors of living species, reflecting the historical, phylogenetic signal present in our data, particularly in morphological characters from fossils. Our results support the widely held but poorly tested intuition that fossils resemble the common ancestors shared by living species, and that fossilizable hard tissues (i.e. bones and teeth) help to reconstruct the evolutionary tree of life.", "keyphrases": ["evolutionary tree", "rodent", "ischyromys", "mouse-related clade", "congruence"]}
{"id": "paleo.000748", "title": "Revised Vertebral Count in the \u201cLongest-Necked Vertebrate\u201d Elasmosaurus platyurus Cope 1868, and Clarification of the Cervical-Dorsal Transition in Plesiosauria", "abstract": "Elasmosaurid plesiosaurians are renowned for their immensely long necks, and indeed, possessed the highest number of cervical vertebrae for any known vertebrate. Historically, the largest count has been attributed to the iconic Elasmosaurus platyurus from the Late Cretaceous of Kansas, but estimates for the total neck series in this taxon have varied between published reports. Accurately determining the number of vertebral centra vis-\u00e0-vis the maximum length of the neck in plesiosaurians has significant implications for phylogenetic character designations, as well as the inconsistent terminology applied to some osteological structures. With these issues in mind, we reassessed the holotype of E. platyurus as a model for standardizing the debated cervical-dorsal transition in plesiosaurians, and during this procedure, documented a \u201clost\u201d cervical centrum. Our revision also advocates retention of the term \u201cpectorals\u201d to describe the usually three or more distinctive vertebrae close to the cranial margin of the forelimb girdle that bear a functional rib facet transected by the neurocentral suture, and thus conjointly formed by both the parapophysis on the centrum body and diapophysis from the neural arch (irrespective of rib length). This morphology is unambiguously distinguishable from standard cervicals, in which the functional rib facet is borne exclusively on the centrum, and dorsals in which the rib articulation is situated above the neurocentral suture and functionally borne only by the transverse process of the neural arch. Given these easily distinguishable definitions, the maximum number of neck vertebrae preserved in E. platyurus is 72; this is only three vertebrae shorter than the recently described Albertonectes, which together with E. platyurus constitute the \u201clongest necked\u201d animals ever to have lived.", "keyphrases": ["vertebrate", "count", "cervical-dorsal transition"]}
{"id": "10.2113/gsjfr.46.2.124", "title": "FORAMINIFERAL RESPONSE TO ECOLOGICAL PERTURBATIONS ALONG THE EASTERN MARGIN OF THE CANADIAN WESTERN INTERIOR SEAWAY, CENOMANIAN-TURONIAN INTERVAL", "abstract": "Ecological perturbations during the Cenomanian-Turonian boundary interval along the eastern margin of the Canadian Western Interior Seaway (WIS) were investigated in a subsurface core from eastern Saskatchewan (distal) and outcrop at the Manitoba Escarpment (proximal). Paleoecological controls on biota included transgressive/regressive cyclicity, the Oceanic Anoxic Event 2, frequent ashfalls, and a stratified water column. Changes in foraminiferal assemblage composition, species richness, and abundance can be correlated between the core and outcrop. The lower Turonian biofacies at both sites is made up exclusively of planktic species, reflecting the persistent bottom water anoxia in the Canadian WIS. The low-diversity assemblage is nearly entirely composed of opportunistic, surface-dwelling species of the genera Muricohedbergella and Heterohelix , responding to water turbidity, reduced salinity, and shallow water depth. Abundances of planktic species are significantly higher in the distal core section. During the early Turonian, diversity slightly increased, with the presence of Whiteinella aprica reflecting periodic improvement of the water column conditions at both sites. The appearance of the clavate species, Clavihedbergella simplex , reflects an expanded oxygen minimum zone, also confirmed by biomarkers, particularly in outcrop. Dwarfing of foraminiferal tests is interpreted as a response to frequent ashfalls that affected the water column. Lowering of sea level during the middle Turonian allowed for seafloor winnowing and caused a brief disappearance of planktic foraminifera. The north-south temperature gradient in the WIS resulted in a lower planktic foraminiferal diversity in what is now Canada compared to the waters that covered what is now the United States and the absence of benthic and deeper-dwelling, keeled planktic species can be attributed to an increasingly well-developed oxygen minimum zone or increasingly stratified water column. The appearance datum of planktic foraminifera is distinctly diachronous along a south to north transect.", "keyphrases": ["ecological perturbation", "eastern margin", "western interior seaway", "oceanic anoxic event", "foraminifera"]}
{"id": "10.1046/j.1365-3091.2000.00293.x", "title": "Evolving turbidite systems on a deforming basin floor, Tabernas, SE Spain", "abstract": "The Tabernas\u2010Sorbas basin was a narrow, east\u2010west trending, marine trough of Late Miocene age. Sediment gravity flow deposits dominate the basin fill and provide a record of changing bathymetry in response to tectonically induced sea bed deformation. A reanalysis of the western end of the basin in the vicinity of Tabernas establishes an upward evolution involving: (1) sand\u2010starved marls that were incised by axial channels recording a period of bypass, during which sand deposition took place in a depocentre further to the east; (2) punctuated infilling of the incisions, locally by high\u2010sinuosity embedded channels. Channel filling is related to a gradient reduction, which presaged collapse of the axial slope as the depocentre began to migrate westwards into the Tabernas area; (3) draping of the earlier incision fills by laterally extensive sheet turbidites, which were initially contained in structurally controlled depressions. These \u2018deeps\u2019 opened up as active faults propagated through the former axial slope. Flow containment is inferred on account of the unusual structure of the sheet sandstone beds, complex palaeoflow relationships and thick mudstone caps; (4) fault\u2010controlled topography was subsequently healed, and further sheet turbidites showing evidence of longer range containment and progressive slope onlap were emplaced. These record mixed supply from both seismically trigged \u2018axial\u2019 failures and a reactivated, fault\u2010controlled slope building out from the northern margin of the basin. Flows traversing the trough floor were strongly reflected off slopes marking the southern limit of the basin. The studied succession is capped by (5) the Gordo megabed event, a large, probably seismically triggered, failure which blanketed the basin floor, demonstrating an enlarged but still contained basin now devoid of significant intrabasinal fault topography. Tectonics played a key role in driving the evolution of the turbidite systems in this basin. Deformation of the basin floor had an important impact on gradients, slope stability, bathymetry and the ability of flows to bypass along the trough axis. Westward migration of the depocentre into the Tabernas area led to a change from incision and bypass to conduit backfilling to flow containment, as fault\u2010induced subsidence generated a \u2018sump\u2019, which trapped flows moving along the basin axis.", "keyphrases": ["turbidite system", "basin floor", "marl"]}
{"id": "paleo.012943", "title": "Allometries of Maximum Growth Rate versus Body Mass at Maximum Growth Indicate That Non-Avian Dinosaurs Had Growth Rates Typical of Fast Growing Ectothermic Sauropsids", "abstract": "We tested if growth rates of recent taxa are unequivocally separated between endotherms and ectotherms, and compared these to dinosaurian growth rates. We therefore performed linear regression analyses on the log-transformed maximum growth rate against log-transformed body mass at maximum growth for extant altricial birds, precocial birds, eutherians, marsupials, reptiles, fishes and dinosaurs. Regression models of precocial birds (and fishes) strongly differed from Case\u2019s study (1978), which is often used to compare dinosaurian growth rates to those of extant vertebrates. For all taxonomic groups, the slope of 0.75 expected from the Metabolic Theory of Ecology was statistically supported. To compare growth rates between taxonomic groups we therefore used regressions with this fixed slope and group-specific intercepts. On average, maximum growth rates of ectotherms were about 10 (reptiles) to 20 (fishes) times (in comparison to mammals) or even 45 (reptiles) to 100 (fishes) times (in comparison to birds) lower than in endotherms. While on average all taxa were clearly separated from each other, individual growth rates overlapped between several taxa and even between endotherms and ectotherms. Dinosaurs had growth rates intermediate between similar sized/scaled-up reptiles and mammals, but a much lower rate than scaled-up birds. All dinosaurian growth rates were within the range of extant reptiles and mammals, and were lower than those of birds. Under the assumption that growth rate and metabolic rate are indeed linked, our results suggest two alternative interpretations. Compared to other sauropsids, the growth rates of studied dinosaurs clearly indicate that they had an ectothermic rather than an endothermic metabolic rate. Compared to other vertebrate growth rates, the overall high variability in growth rates of extant groups and the high overlap between individual growth rates of endothermic and ectothermic extant species make it impossible to rule out either of the two thermoregulation strategies for studied dinosaurs.", "keyphrases": ["maximum growth rate", "body mass", "ectothermic", "endothermic metabolic rate"]}
{"id": "10.1080/01916122.2010.501164", "title": "Palynoflora of the Late Paleocene Silicified Shale at Almont, North Dakota, USA", "abstract": "A pollen and spore assemblage of 50 species was recovered from the late Paleocene (pollen zone P5) Almont locality in the Williston Basin, central North Dakota, USA. This palynoflora was extracted from the same layer containing a diverse megaflora preserved in a silicified shale with compressed leaves, and anatomically preserved fruits and seeds. More than 44 megafossil genera assignable to 26 extant plant families thus far have been recognized. The palynomorphs, which are of exceptional preservation, were examined using the same-grain technique with both light microscopy (LM) and scanning electron microscopy (SEM). Additional LM and SEM studies augmented the same grain studies to provide an understanding of sculptural features, and additional, rare taxa. Of particular note are the in situ pollen types known from catkins and pollen cones, allowing for confirmation of the dispersed pollen's systematic position by tying it to its parent plant. Taxa for which in situ pollen is known from Almont include taxodiaceous conifers, Betulaceae, Hamamelidaceae, Juglandaceae, and Platanaceae, and several catkins of uncertain affinities, some with monosulcate grains. This study emphasizes the role of palynology in providing an expanded view of the flora from palynomorphs for comparison with a rich megafossil assemblage.", "keyphrases": ["paleocene", "palynoflora", "reliable fossil record"]}
{"id": "paleo.005378", "title": "Morphological and functional changes in the vertebral column with increasing aquatic adaptation in crocodylomorphs", "abstract": "The lineage leading to modern Crocodylia has undergone dramatic evolutionary changes in morphology, ecology and locomotion over the past 200+\u2009Myr. These functional innovations may be explained in part by morphological changes in the axial skeleton, which is an integral part of the vertebrate locomotor system. Our objective was to estimate changes in osteological range of motion (RoM) and intervertebral joint stiffness of thoracic and lumbar vertebrae with increasing aquatic adaptation in crocodylomorphs. Using three-dimensional virtual models and morphometrics, we compared the modern crocodile Crocodylus to five extinct crocodylomorphs: Terrestrisuchus, Protosuchus, Pelagosaurus, Steneosaurus and Metriorhynchus, which span the spectrum from terrestrial to fully aquatic. In Crocodylus, we also experimentally measured changes in trunk flexibility with sequential removal of osteoderms and soft tissues. Our results for the more aquatic species matched our predictions fairly well, but those for the more terrestrial early crocodylomorphs did not. A likely explanation for this lack of correspondence is the influence of other axial structures, particularly the rigid series of dorsal osteoderms in early crocodylomorphs. The most important structures for determining RoM and stiffness of the trunk in Crocodylus were different in dorsoventral versus mediolateral bending, suggesting that changes in osteoderm and rib morphology over crocodylomorph evolution would have affected movements in some directions more than others.", "keyphrases": ["vertebral column", "aquatic adaptation", "crocodylomorph", "evolutionary change", "locomotion"]}
{"id": "paleo.001350", "title": "Fossil snake preserving three trophic levels and evidence for an ontogenetic dietary shift", "abstract": "We report a fossil snake from the middle Eocene (48 Ma) Messel Pit, in whose stomach is a lizard, in whose stomach is an insect. This is the second known vertebrate fossil containing direct evidence of three trophic levels. The snake is identified as a juvenile of Palaeopython fischeri on the basis of new characters of the skull; the lizard is identified as Geiseltaliellus maarius, a stem-basilisk; and the insect, despite preserved structural colouration, could not be identified more precisely. G. maarius is thought to have been an arboreal species, but like its extant relatives may have foraged occasionally on the ground. Another, larger specimen of G. maarius preserves plant remains in the digestive tract, suggesting that omnivory in this species may have been common in larger individuals, as in extant Basiliscus and Polychrus. A general picture of the trophic ecology of P. fischeri is not yet possible, although the presence of a lizard in the stomach of a juvenile individual suggests that this snake could have undergone a dietary shift, as in many extant boines.", "keyphrases": ["trophic level", "dietary shift", "lizard", "insect", "fossil snake"]}
{"id": "paleo.010391", "title": "Testing Adaptive Hypotheses of Convergence with Functional Landscapes: A Case Study of Bone-Cracking Hypercarnivores", "abstract": "Morphological convergence is a well documented phenomenon in mammals, and adaptive explanations are commonly employed to infer similar functions for convergent characteristics. I present a study that adopts aspects of theoretical morphology and engineering optimization to test hypotheses about adaptive convergent evolution. Bone-cracking ecomorphologies in Carnivora were used as a case study. Previous research has shown that skull deepening and widening are major evolutionary patterns in convergent bone-cracking canids and hyaenids. A simple two-dimensional design space, with skull width-to-length and depth-to-length ratios as variables, was used to examine optimized shapes for two functional properties: mechanical advantage (MA) and strain energy (SE). Functionality of theoretical skull shapes was studied using finite element analysis (FEA) and visualized as functional landscapes. The distribution of actual skull shapes in the landscape showed a convergent trend of plesiomorphically low-MA and moderate-SE skulls evolving towards higher-MA and moderate-SE skulls; this is corroborated by FEA of 13 actual specimens. Nevertheless, regions exist in the landscape where high-MA and lower-SE shapes are not represented by existing species; their vacancy is observed even at higher taxonomic levels. Results highlight the interaction of biomechanical and non-biomechanical factors in constraining general skull dimensions to localized functional optima through evolution.", "keyphrases": ["convergence", "case study", "fea"]}
{"id": "10.1098/rsos.160518", "title": "Whence the beardogs? Reappraisal of the Middle to Late Eocene \u2018Miacis\u2019 from Texas, USA, and the origin of Amphicyonidae (Mammalia, Carnivora)", "abstract": "The Middle to Late Eocene sediments of Texas have yielded a wealth of fossil material that offers a rare window on a diverse and highly endemic mammalian fauna from that time in the southern part of North America. These faunal data are particularly significant because the narrative of mammalian evolution in the Paleogene of North America has traditionally been dominated by taxa that are known from higher latitudes, primarily in the Rocky Mountain and northern Great Plains regions. Here we report on the affinities of two peculiar carnivoraforms from the Chambers Tuff of Trans-Pecos, Texas, that were first described 30 years ago as Miacis cognitus and M. australis. Re-examination of previously described specimens and their inclusion in a cladistic analysis revealed the two taxa to be diminutive basal amphicyonids; as such, they are assigned to new genera Gustafsonia and Angelarctocyon, respectively. These two taxa fill in some of the morphological gaps between the earliest-known amphicyonid genus, Daphoenus, and other Middle-Eocene carnivoraforms, and lend additional support for a basal caniform position of the beardogs outside the Canoidea. The amphicyonid lineage had evidently given rise to at least five rather distinct forms by the end of the Middle Eocene. Their precise geographical origin remains uncertain, but it is plausible that southern North America served as an important stage for a very early phase of amphicyonid radiation.", "keyphrases": ["beardog", "middle", "texas"]}
{"id": "10.1073/pnas.0408921102", "title": "Stable isotopes (\u03b413C and \u03b415N) of organic matrix from coral skeleton", "abstract": "The evolutionary success of reef-building corals in nutrient-poor tropical waters is attributed to endosymbiotic dinoflagellates. The algae release photosynthetic products to the coral animal cells, augment nutrient flux, and enhance the rate of coral calcification. Natural abundance of stable isotopes (\u03b413C and \u03b418O) provides answers to modern and paleobiological questions about the effect of photosymbiosis on sources of carbon and oxygen in coral skeletal calcium carbonate. Here we compare 17 species of symbiotic and nonsymbiotic corals to determine whether evidence for photosymbiosis appears in stable isotopes (\u03b413C and \u03b415N) of an organic skeletal compartment, the coral skeletal organic matrix (OM). Mean OM \u03b413C in symbiotic and nonsymbiotic corals was similar (-26.08\u2030 vs. -24.31\u2030), but mean OM \u03b415N was significantly depleted in 15N in the former (4.09\u2030) relative to the latter (12.28\u2030), indicating an effect of the algae on OM synthesis and revealing OM \u03b415N as a proxy for photosymbiosis. To answer an important paleobiological question about the origin of photosymbiosis in reef-building corals, we applied this proxy test to a fossil coral (Pachythecalis major) from the Triassic (240 million years ago) in which OM is preserved. Mean OM \u03b415N was 4.66\u2030, suggesting that P. major was photosymbiotic. The results show that symbiotic algae augment coral calcification by contributing to the synthesis of skeletal OM and that they may have done so as early as the Triassic.", "keyphrases": ["organic matrix", "photosymbiosis", "fossil coral", "stable isotope"]}
{"id": "10.1080/14772019.2017.1391342", "title": "Discovery of a long-term refuge for ostracods (Crustacea) after the end-Permian extinction: a unique Carnian (Late Triassic) fauna from the Mersin M\u00e9lange, southern Turkey", "abstract": "The Mersin M\u00e9lange, located in southern Turkey north-west of the city of Mersin, includes blocks and tectonic slices of different origins. The Kilek section in the Mersin M\u00e9lange was sampled for a thorough examination of its lithology, biostratigraphy and fossil content. Two samples from the cherty limestone layers within the Huglu Tuffites at the top of the section yielded a rich silicified ostracod fauna of late Early Carnian (based on a two-fold Carnian subdivision) or middle Middle Carnian age (based on a three-fold Carnian subdivision), deposited in an open marine environment, in the outer platform-upper slope zone. We report 121 ostracod species belonging to 53 genera. Two new genera are described: Edithobairdia Forel gen. nov. and Gencella Forel gen. nov., as well as 16 new species: Acanthoscapha mersinella Forel sp. nov., Bairdia hugluensis Forel sp. nov., Acratia kollmanni Forel sp. nov., Citrella? carniana Forel sp. nov., Cytheropteron? schornikovi Forel sp. nov., Eucytherura lacerata Forel sp. nov., Gencella taurensis Forel sp. nov., Kerocythere dorsidenticulata Forel sp. nov., Kerocythere tricostata Forel sp. nov., Monoceratina praevulsaformis Forel sp. nov., Patellacythere tourkosella Forel sp. nov., Polycope kilekensis Forel sp. nov., Ptychobairdia praekristanae Forel sp. nov., Simeonella daginikella Forel sp. nov., Spinomicrocheilinella reliquiaella Forel sp. nov. and Triassocythere tavuscayiriensis Forel sp. nov. The diagnosis of Acratia goemoeryi Kozur is emended. The Kilek fauna retains primitive characteristics illustrated by the first known occurrence of Palaeocopida and Rectonariidae (typical Palaeozoic forms) in the Late Triassic, associated with typical Triassic\u2013modern elements such as thick-shelled and ornamented Bairdiidae and diverse Cytheroidea known from the Middle and Late Triassic worldwide. The unique composition of Palaeozoic and Mesozoic taxa from the Kilek section illustrates unexpected long-term survival in a deep-sea refuge zone following the end-Permian extinction, and the diachronous character of the ostracod recovery in different environments. http://zoobank.org/urn:lsid:zoobank.org.pub:662C3D5C\u20132B86\u20134D7B\u2013BDB5\u20138F8B6A1AD1E7", "keyphrases": ["ostracod", "end-permian extinction", "late triassic", "kilek section"]}
{"id": "10.1017/jpa.2017.49", "title": "A problematic cnidarian (Cambroctoconus; Octocorallia?) from the Cambrian (Series 2\u20133) of Laurentia", "abstract": "Abstract. The problematic calcified cnidarian Cambroctoconus is described from the Henson Gletscher Formation (Cambrian Series 2, Stage 4\u2014Series 3, Stage 5) of North Greenland, representing the first record from Laurentia of a genus otherwise recently described from China, Kyrgyzstan, and Korea. Internal molds produced by penetrative phosphatization mirror the pervasive pore system of the calice walls and septa. The pore system is compared to the network of gastrodermal solenia that distributes nutrients between polyps and surrounding stolon tissues in present day octocorals. In conjunction with the octagonal form of the individual coralla and eight-fold symmetry of septa, the pore system promotes assignment of Cambroctoconus to the Octocorallia, a basal clade in cnidarian phylogeny. Octocorals (\u2018soft corals\u2019) are diverse in present day seas, but have a poor fossil record despite the general development of distinctive calcareous spicules. New taxa: Order Cambroctoconida new; Cambroctoconus koori new species.", "keyphrases": ["cambroctoconus", "octocorallia", "laurentia", "north greenland"]}
{"id": "10.1002/2016PA002940", "title": "Environmental perturbations at the early Eocene ETM2, H2, and I1 events as inferred by Tethyan calcareous plankton (Terche section, northeastern Italy)", "abstract": "Several early Eocene hyperthermals have been recently investigated and characterized in terms of temperature anomalies and oceanographic changes. The effects of these climatic perturbations on biotic communities are much less constrained. Here we present new records from the Terche section (northeastern Italy) that, for the first time, integrates data on planktic foraminifera and calcareous nannofossils across three post Paleocene-Eocene Thermal Maximum (PETM) negative carbon isotope excursions (CIEs). The bio-magnetostratigraphic framework generated at Terche allows us to confidently relate such CIEs to the Eocene Thermal Maximum 2 (ETM2), H2, and I1 events. Each of these events coincides with lithological anomalies characterized by significantly lower calcium carbonate content (marly-units, MUs). We interpret these MUs as mainly linked to an effect of increased terrigenous dilution, as dissolution proxies do not display significant variations. Calcareous plankton assemblages change significantly across these events and radiolarians increase. Observed changes suggest that transient warming and environmental perturbations, though more intense during ETM2, occurred during each of the three investigated perturbations. Variations among calcareous plankton suggest increase in surface-water eutrophication with respect to the pre-events conditions, coupled with a weakening of the upper water-column thermal stratification. Higher nutrient discharge was related to intensification of the hydrological cycle as a consequence of the warmer climate. These conditions persisted during the early CIE recovery, implying slower recovery rates for the environment and biota than for the carbon cycle.", "keyphrases": ["calcareous plankton", "warming", "environmental perturbation"]}
{"id": "10.1144/SP342.4", "title": "Aeolian sediment evidence that global cooling has driven late Cenozoic stepwise aridification in central Asia", "abstract": "Abstract It has been a long held view that uplift of the Tibetan Plateau dominated stepwise climatic drying in central Asia during the late Cenozoic. On the other hand, global cooling may also have forced Asian drying and the subsequent formation of aeolian deposits in north China. Until now, whether the Tibetan uplift or the global cooling has been the first-order driver controlling stepwise Asian drying has remained a contentious issue. In this study, we examine the thick aeolian silt deposit, which is regarded as a good archive of palaeoclimatic changes in central Asia and north China, in order to qualitatively reconstruct the drying process in Asia during the late Cenozoic. On the basis of our long-term field surveys, laboratory analyses and previous investigations, we have obtained time sequences of Asian drying from the early Miocene to late Pleistocene; we compare this newly reconstructed time series of Asian aridification with the time series of global cooling and Tibetan uplift to identify the first-order driver of stepwise Asian aridification. A good match between the drying and global cooling might indicate that global cooling was the most likely driver of stepwise drying in interior Asia. On the other hand, controversy regarding timing and amplitude of Tibetan uplift during the late Cenozoic suggests that the prevailing conclusion that Tibetan uplift forces Asian drying should be regarded as immature. A mechanism that global cooling drove the Asian drying is tentatively suggested.", "keyphrases": ["global cooling", "cenozoic", "aridification"]}
{"id": "10.1080/09853111.2000.11105377", "title": "The Ligurian Helminthoid flysch units of the Emilian Apennines: stratigraphic and petrographic features, paleogeographic restoration and structural evolution", "abstract": "Abstract This work deals with the Cretaceous-Tertiary Helminthoid flysch successions of the Emilian Apennines and related basal complexes (Mt. Caio, Val Baganza, Solignano, Mt. Venere-Monghidoro and Mt. Cassio Units): it is based on an integrated approach which included stratigraphic, petrographic and structural observations. Detailed stratigraphic sections measured in the various successions evidenced the specific features of the different flysch formations. The main framework composition analysis of the arenites pointed out a partly \u2018oceanic\u2019 alimentation for the Mt. Caio Flysch Fm; the Mt. Venere-Monghidoro, and Mt. Cassio Flysch Fms have been alimented exclusively by a terrigenous detritus mainly derived from continental basement source areas. The heavy mineral assemblage of the Mt. Caio Flysch Fm is characterized by picotite, that of the Mt. Venere-Monghidoro, Solignano and Mt. Cassio Flysch Fms commonly contains straurolite, garnet and chloritoid, generally considered to be typical products of the Adriatic continental margin. The calcareous nannofossils biostratigraphy indicated that the flysch sedimentation started during the Late Campanian and ended between the Paleocene (Mt. Cassio Flysch Fm and Mt. Venere-Monghidoro Fms) and the Middle Eocene (Mt. Caio Flysch Fm). We propose a schematic paleogeographic restoration for the External Ligurian Domain which implies a more internal position for the Mt. Caio succession and a more external one for the Mt. Venere-Monghidoro and Mt. Cassio successions. The Helminthoid flyschs sedimented after and during deformation and subduction phases in perched and fore-arc basins partly overlying the marginal part of the Adriatic plate. The External Ligurian nappes\u2019 stacking consists, in the study area, from the bottom, of the following units: Caio Unit, Val Baganza Ophiolitic Unit, Monghidoro Unit, Cassio Unit. This pile of thrust-nappes, sealed by the Epiligurian succession, has been already realized before Late Eocene. In our opinion it was generated by a frontal west-verging frontal accretion process (offscraping), which let the flysch successions remain, in this phase, quite undeformed. This westverging thrusting phase, starting from the Middle-Late Eocene, has been followed by an important folding event which generated striking hectometric and kilometric \u2018Apenninic\u2019 reverse folds, sometimes associated with NE-verging thrust surfaces. The Oligocene and post-Oligocene evolution is characterized by a block-translation of the Ligurian staking over the Subligurian, Tuscan and Umbrian Domains, associated with a new generation of minor thrusts and thrust related Apenninic folds. \u00a9 2000 \u00c9ditions scientifiques et m\u00e9dicales Elsevier SAS", "keyphrases": ["helminthoid", "emilian apennines", "paleogeographic restoration", "calcareous nannofossil biostratigraphy", "middle eocene"]}
{"id": "10.1098/rsbl.2020.0809", "title": "A new somasteroid from the Fezouata Lagerst\u00e4tte in Morocco and the Early Ordovician origin of Asterozoa", "abstract": "The somasteroids are Lower Palaeozoic star-shaped animals widely regarded as ancestors of Asterozoa, the group of echinoderms that includes brittle stars and starfish. However, the origin of asterozoans, the assembly of their distinctive body organization, and their relationships with other Cambrian and Ordovician echinoderms remain problematic owing to the difficulties of comparing the endoskeleton between disparate groups. Here, we describe the new somasteroid Cantabrigiaster fezouataensis, a primitive asterozoan from the Early Ordovician Fezouata Lagerst\u00e4tte in Morocco. Cantabrigiaster shares with other somasteroids a unique endoskeletal arm organization and the presence of rod-like virgal ossicles that articulate with the ambulacrals, but differs from all other known asterozoans in the absence of adambulacral ossicles defining the arm margins, evoking parallels with non-asterozoan echinoderms. Developmentally informed Bayesian and parsimony phylogenetic analyses, which reflect the homology of the biserial ambulacral ossicles in Palaeozoic echinoderms according to the extraxial\u2013axial theory, recover Cantabrigiaster as the earliest divergent stem-group asterozoan. Our results illuminate the ancestral morphology of Asterozoa, and clarify the affinities of problematic Ordovician Asterozoa. Bayesian inference and parsimony demonstrate that somasteroids represent a paraphyletic grade within stem- and crown-group Asterozoa, whereas stenuroids are paraphyletic within stem-group Ophiuroidea. Our results also offer potential insights on the evolutionary relationships between asterozoans, crinoids and potential Cambrian stem-group representatives.", "keyphrases": ["somasteroid", "asterozoa", "phylogenetic analysis"]}
{"id": "paleo.011128", "title": "An Early Triassic sauropterygian and associated fauna from South China provide insights into Triassic ecosystem health", "abstract": "The timing and pattern of biotic recovery from the Permo-Triassic Mass Extinction remains elusive. Here we report new material of the Early Triassic sauropterygian Lariosaurus sanxiaensis and associated fauna from the Jialingjiang Formation in Hubei Province, South China. Phylogenetic analysis based on a novel data matrix of sauropterygians recognizes L. sanxiaensis as a basal nothosaur. Stratigraphic congruence analysis shows that the new phylogenetic consensus tree matches to the stratigraphic distribution of sauropterygians very well. The diversified reptilian fauna and inferred simple food web in the Nanzhang-Yuan\u2019an fauna where L. sanxiaensis was discovered suggest that the Triassic biotic recovery adopted a top-down pattern, in contrast to the prevailing view. Comparison with the Middle Triassic Luoping biota from the same carbonate platform suggests that the Triassic biotic recovery is delayed and healthy ecosystems were not established until the Middle Triassic in South China.", "keyphrases": ["associated fauna", "south china", "jialingjiang formation", "phylogenetic analysis", "middle triassic"]}
{"id": "10.3732/ajb.1500004", "title": "Assessing the evolutionary history of the class Synurophyceae (Heterokonta) using molecular, morphometric, and paleobiological approaches.", "abstract": "PREMISE OF THE STUDY\nHeterokont algae of the class Synurophyceae, characterized by distinctive siliceous scales that cover the surface of the cell, are ecologically important in inland waters, yet their evolutionary history remains enigmatic. We explore phylogenetic relationships within this group of algae relative to geologic time, with a focus on evolution of siliceous components.\n\n\nMETHODS\nWe combined an expansive five-gene and time-calibrated molecular phylogeny of synurophyte algae with an extensive array of fossil specimens from the middle Eocene to infer evolutionary trends within the group.\n\n\nKEY RESULTS\nThe group originated in the Jurassic approximately 157 million years ago (Ma), with the keystone genera Mallomonas and Synura diverging during the Early Cretaceous at 130 Ma. Mallomonas further splits into two major subclades, signaling the evolution of the V-rib believed to aid in the spacing and organization of scales on the cell covering. Synura also diverges into two primary subclades, separating taxa with forward-projecting spines on the scale from those with a keel positioned on the scale proper. Approximately one third of the fossil species are extinct, whereas the remaining taxa are linked to modern congeners.\n\n\nCONCLUSIONS\nThe taxonomy of synurophytes, which relies extensively on the morphology of the siliceous components, is largely congruent with molecular analyses. Scales of extinct synurophytes were significantly larger than those of modern taxa and may have played a role in their demise. In contrast, many fossil species linked to modern lineages were smaller in the middle Eocene, possibly reflecting growth in the greenhouse climatic state that characterized this geologic interval.", "keyphrases": ["evolutionary history", "class synurophyceae", "synurophyte", "synura", "fossil specie"]}
{"id": "paleo.003203", "title": "The Taxonomy and Anatomy of Rauisuchian Archosaurs from the Late Triassic of Germany and Poland", "abstract": "The German Late Triassic archosaur Teratosaurus suevicus is a historically important taxon, being the first described rauisuchian. Unfortunately the holotype is a single element, a maxilla, which is poorly preserved and incomplete. We redescribe this maxilla and identify a single potential autapomorphy. The fragmentary type specimen complicates attempts to refer additional material to this taxon, and other unassociated archosaur and rauisuchian specimens from the Mittlerer Stubensandstein of Germany cannot be referred to T. suevicus with any degree of confidence. The stratigraphically older T. silesiacus, from the upper Carnian of Poland, is represented by a much more complete and better preserved specimen. Comparison of the maxillae of T. suevicus and T. silesiacus reveals that the two are distinct taxa, contra recent suggestions, but also that they do not share any synapomorphies or a unique combination of characters relative to Postosuchus kirkpatricki and other rauisuchians. Thus, the Polish material must be transferred to a new genus, Polonosuchus gen. nov. Both Polonosuchus and Teratosaurus are very similar to Postosuchus kirkpatricki, and the three taxa are likely closely related.", "keyphrases": ["archosaur", "germany", "poland"]}
{"id": "paleo.009464", "title": "Extended dilation of the radiocarbon time scale between 40,000 and 48,000 y BP and the overlap between Neanderthals and Homo sapiens", "abstract": "The new radiocarbon calibration curve (IntCal20) allows us to calculate the gradient of the relationship between 14C age and calendar age over the past 55 millennia before the present (55 ka BP). The new gradient curve exhibits a prolonged and prominent maximum between 48 and 40 ka BP during which the radiocarbon clock runs almost twice as fast as it should. This radiocarbon time dilation is due to the increase in the atmospheric 14C/12C ratio caused by the 14C production rise linked to the transition into the Laschamp geomagnetic excursion centered around 41 ka BP. The major maximum in the gradient from 48 to 40 ka BP is a new feature of the IntCal20 calibration curve, with far-reaching impacts for scientific communities, such as prehistory and paleoclimatology, relying on accurate ages in this time range. To illustrate, we consider the duration of the overlap between Neanderthals and Homo sapiens in Eurasia.", "keyphrases": ["overlap", "neanderthals", "radiocarbon calibration curve"]}
{"id": "paleo.012190", "title": "The rise of angiosperms pushed conifers to decline during global cooling", "abstract": "Significance Competition for common resources can make some species groups thrive and others decline. Flowering plants rose to dominance between 125 and 80 Ma, undergoing an explosive radiation that is believed to have impacted long-established plant groups like gymnosperms. Here, we show that the decline of conifers is strongly and directly linked to the increasing diversity of flowering plants. Both the fossil record and molecular data converge in clarifying the effects of abiotic or biotic factors on the speciation and extinction rates of conifers. These results imply that long-term biological interactions through clade competition can play a more important role in the rise and demise of major organism groups than mass extinctions. Competition among species and entire clades can impact species diversification and extinction, which can shape macroevolutionary patterns. The fossil record shows successive biotic turnovers such that a dominant group is replaced by another. One striking example involves the decline of gymnosperms and the rapid diversification and ecological dominance of angiosperms in the Cretaceous. It is generally believed that angiosperms outcompeted gymnosperms, but the macroevolutionary processes and alternative drivers explaining this pattern remain elusive. Using extant time trees and vetted fossil occurrences for conifers, we tested the hypotheses that clade competition or climate change led to the decline of conifers at the expense of angiosperms. Here, we find that both fossil and molecular data show high congruence in revealing 1) low diversification rates, punctuated by speciation pulses, during warming events throughout the Phanerozoic and 2) that conifer extinction increased significantly in the Mid-Cretaceous (100 to 110 Ma) and remained high ever since. Their extinction rates are best explained by the rise of angiosperms, rejecting alternative models based on either climate change or time alone. Our results support the hypothesis of an active clade replacement, implying that direct competition with angiosperms increased the extinction of conifers by pushing their remaining species diversity and dominance out of the warm tropics. This study illustrates how entire branches on the Tree of Life may actively compete for ecological dominance under changing climates.", "keyphrases": ["angiosperm", "conifer", "diversification"]}
{"id": "paleo.006445", "title": "Palaeodiversity of Cricetodontini during the late Aragonian (middle Miocene) from the European basins", "abstract": "The results of our study on the record of the tribe Cricetodontini (Cricetidae, Rodentia, Mammalia) from the European latest middle Miocene (Calatayud-Daroca and Vall\u00e8s-Pened\u00e8s basins from Spain, several fissure fillings from France and several basins and karstic sites from central and eastern Europe) is presented here. We have analysed the morphological and diversity patterns of the Cricetodontini and compared them with those described in the Calatayud-Daroca Basin in order to evaluate the presence of a general pattern of the tribe on a European scale. Our findings show the presence of a high diversity of Cricetodontini during the late Aragonian (13.80-10.77 Ma) in all of the areas studied in Europe to date, and that this period of high diversity followed an interval of low diversity of species with basal morphology. The Cricetodontini shows a high morphological diversity during the late Aragonian, and the species present different combinations of features as well as a high degree of endemicity. These results are in accordance with the evolutionary patterns recently described from the Spanish Calatayud-Daroca Basin. The late Aragonian, throughout all of Europe, represents a dramatic and important interval for the evolutionary history of the Cricetodontini.", "keyphrases": ["cricetodontini", "late aragonian", "middle miocene", "eurasian rodent"]}
{"id": "paleo.009367", "title": "Tracking down the White Plague. Chapter two: The role of endocranial abnormal blood vessel impressions and periosteal appositions in the paleopathological diagnosis of tuberculous meningitis", "abstract": "Although endocranial abnormal blood vessel impressions (ABVIs) and periosteal appositions (PAs) have been considered as paleopathological diagnostic criteria for tuberculous meningitis (TBM) based on findings of previous studies, they are not pathognomonic for tuberculosis (TB). Therefore, their utilization in the paleopathological practice can be questioned, especially in consideration that most of the previous studies were not performed on identified skeletal collections but on osteoarchaeological material and did not include statistical data analysis. To fill the aforementioned research gap, for the first time, a macroscopic investigation was conducted on identified pre-antibiotic era skeletons from the Terry Collection. A sample set of 234 individuals who died of TB (TB group) and 193 individuals who died of non-tuberculous causes (NTB group) were examined. The frequency of ABVIs and PAs, as well as other probable TB-related lesions was recorded. To determine the significance of difference (if any) in the frequencies of ABVIs and PAs between the two groups, \u03c72 testing of our data was performed. We found that ABVIs, PAs, and their co-occurrence with each other and with other probable TB-related lesions were more common in the TB group than in the NTB group. In addition, the \u03c72 comparative frequencies of ABVIs and PAs revealed a statistically significant difference between individuals who died of TB and individuals who died of NTB causes. Our findings strengthen those of previous studies that ABVIs and PAs are not specific to TBM but can be of tuberculous origin. Therefore, they do have a diagnostic value in the identification of TB in human osteoarchaeological material, especially when they simultaneously occur with other probable TB-related lesions. Their prudent utilization provides paleopathologists with a stronger basis for diagnosing TB and consequently, a more sensitive means of assessing TB frequency in past human populations.", "keyphrases": ["blood vessel impression", "periosteal apposition", "paleopathological diagnosis", "skeletal collection"]}
{"id": "paleo.001830", "title": "Impact of the Late Triassic mass extinction on functional diversity and composition of marine ecosystems", "abstract": "Mass extinctions have profoundly influenced the history of life, not only through the death of species but also through changes in ecosystem function and structure. Importantly, these events allow us the opportunity to study ecological dynamics under levels of environmental stress for which there are no recent analogues. Here, we examine the impact and selectivity of the Late Triassic mass extinction event on the functional diversity and functional composition of the global marine ecosystem, and test whether post\u2010extinction communities in the Early Jurassic represent a regime shift away from pre\u2010extinction communities in the Late Triassic. Our analyses show that, despite severe taxonomic losses, there is no unequivocal loss of global functional diversity associated with the extinction. Even though no functional groups were lost, the extinction event was, however, highly selective against some modes of life, in particular sessile suspension feeders. Although taxa with heavily calcified skeletons suffered higher extinction than other taxa, lightly calcified taxa also appear to have been selected against. The extinction appears to have invigorated the already ongoing faunal turnover associated with the Mesozoic Marine Revolution. The ecological effects of the Late Triassic mass extinction were preferentially felt in the tropical latitudes, especially amongst reefs, and it took until the Middle Jurassic for reef ecosystems to fully recover to pre\u2010extinction levels.", "keyphrases": ["functional diversity", "marine ecosystem", "sessile suspension feeder", "reef"]}
{"id": "paleo.006606", "title": "Small within the largest: brain size and anatomy of the extinct Neoepiblema acreensis, a giant rodent from the Neotropics", "abstract": "The ecomorphological diversity of caviomorph rodents in South America included giant forms, such as the chinchilloid Neoepiblema acreensis from the Upper Miocene of Brazil. The evolution of the brain anatomy and size of these animals can be now studied with non-invasive imaging techniques and exceptional fossils. Caviomorphs show diversity in the traits of the olfactory bulbs, cerebrum, cerebellum, cranial nerves, and blood vessels. Neoepiblema acreensis had a gyrencephalic brain, with an expansion of the frontal lobe, lacking an evident paraflocculus. Compared to the predictions based on extant taxa, even when considering taphonomical effects, N. acreensis, a rodent that weighted almost 80 kg, had a very low encephalization quotient compared to other rodents. The adaptive value of a low energetic cost and other ecological factors could explain the presence of a small brain in this giant rodent\u2013\u2013a pattern we also hypothesize for other Neogene giant rodents.", "keyphrases": ["neoepiblema acreensis", "giant rodent", "caviomorph"]}
{"id": "paleo.005970", "title": "Failed prey or peculiar necrolysis? Isolated ammonite soft body from the Late Jurassic of Eichst\u00e4tt (Germany) with complete digestive tract and male reproductive organs", "abstract": "Ammonoid soft parts have been rarely described. Here, we document the soft parts of a perisphinctid ammonite from the early Tithonian of Wintershof near Eichst\u00e4tt (Germany). This exceptional preservation was enabled by the special depositional conditions in the marine basins of the Solnhofen Archipelago. Here, we document this find and attempt to homologize its parts with various organs such as the digestive tract, reproductive organs, the mantle cavity with gills, and the hyponome, with differing degrees of reservation. Alternative interpretations are also taken into account. We suggest that the soft parts were separated from the conch either taphonomically (following necrolytical processes affecting the attachment structures) or during a failed predation, where a predator (fish or coleoid) removed the soft parts from the conch but then dropped them. This find is interesting because it adds to the knowledge of ammonite anatomy, which is normally hidden in the conch. The reproductive organs show traces of what might have been spermatophores, thus supporting the hypothesis that the microconchs represented the males.", "keyphrases": ["germany", "digestive tract", "reproductive organ"]}
{"id": "paleo.009964", "title": "Morphometry, Bite-Force, and Paleobiology of the Late Miocene Caiman Purussaurus brasiliensis", "abstract": "Purussaurus brasiliensis thrived in the northwestern portion of South America during the Late Miocene. Although substantial material has been recovered since its early discovery, this fossil crocodilian can still be considered as very poorly understood. In the present work, we used regression equations based on modern crocodilians to present novel details about the morphometry, bite-force and paleobiology of this species. According to our results, an adult Purussaurus brasiliensis was estimated to reach around 12.5 m in length, weighing around 8.4 metric tons, with a mean daily food intake of 40.6 kg. It was capable of generating sustained bite forces of 69,000 N (around 7 metric tons-force). The extreme size and strength reached by this animal seems to have allowed it to include a wide range of prey in its diet, making it a top predator in its ecosystem. As an adult, it would have preyed upon large to very large vertebrates, and, being unmatched by any other carnivore, it avoided competition. The evolution of a large body size granted P. brasiliensis many advantages, but it may also have led to its vulnerability. The constantly changing environment on a large geological scale may have reduced its long-term survival, favoring smaller species more resilient to ecological shifts.", "keyphrases": ["bite-force", "paleobiology", "wide range", "body size", "morphometry"]}
{"id": "10.2113/50.Suppl_1.5", "title": "From living communities to fossil assemblages: origin and fate of coccolithophores in the northern Arabian Sea", "abstract": "The use of coccolithophores as proxies for past environmental conditions in the Arabian Sea is critically evaluated based on a number of recent studies. We investigated coccolithophores in terms of their production in the photic zone, their transformation to settling assemblages, their accumulation on the seafloor, and their final burial in the sediments. The living coccolithophore communities reflect local oceanographic conditions and seem to be more dependent on mixed layer depth and nutrient availability than on temperature and/or salinity changes. We found a strong seasonality in coccolithophore fluxes corresponding to the seasonal monsoonal development. Several species showed specific annual trends, however, the annual cycles of the majority of living species are not preserved and only a smoothed signal with gradual intraannual changes characterize the settling assemblages. In the surface sediments the distribution of species and species groups reflect the environmental parameters of the overlying water masses and may be successfully used to improve paleoclimatic reconstructions. Even though sediments in the Arabian Sea are annually laminated within an expanded oxygen minimum zone, no seasonal signal is preserved due to the event-like deposition of light laminae. However, interannual variability can be studied with a unique resolution. Differences in the species compositions of living coccolithophore communities, settling, and sediment assemblages result from taxonomical and preservational factors. Interpretation of variations of species compositions and abundances in the fossil record are further complicated by evolutionary shifts and events and changing environmental conditions (e.g. fluctuation of sedimentation rate). Despite all limitations and constraints, it is shown that the fossil coccolithophore core records bear great potentials to successfully monitor and reconstruct paleoenvironmental changes.", "keyphrases": ["coccolithophore", "arabian sea", "great potential"]}
{"id": "paleo.009425", "title": "Paleogenomics illuminates the evolutionary history of the extinct Holocene \u201chorned\u201d crocodile of Madagascar, Voay robustus", "abstract": "Ancient DNA is transforming our ability to reconstruct historical patterns and mechanisms shaping modern diversity and distributions. In particular, molecular data from extinct Holocene island faunas have revealed surprising biogeographic scenarios. Here, we recovered partial mitochondrial (mt) genomes for 1300\u20131400 year old specimens (n = 2) of the extinct \u201chorned\u201d crocodile, Voay robustus, collected from Holocene deposits in southwestern Madagascar. Phylogenetic analyses of partial mt genomes and tip-dated timetrees based on molecular, fossil, and stratigraphic data favor a sister group relationship between Voay and Crocodylus (true crocodiles). These well supported trees conflict with recent morphological systematic work that has consistently placed Voay within Osteolaeminae (dwarf crocodiles and kin) and provide evidence for likely homoplasy in crocodylian cranial anatomy and snout shape. The close relationship between Voay and Crocodylus lends additional context for understanding the biogeographic origins of these genera and refines competing hypotheses for the recent extinction of Voay from Madagascar.", "keyphrases": ["crocodile", "madagascar", "voay robustus"]}
{"id": "10.1073/pnas.0503108102", "title": "Anterior tooth growth periods in Neandertals were comparable to those of modern humans.", "abstract": "A longstanding controversy in paleoanthropology surrounds the question of whether Neandertals shared the prolonged growth periods of modern humans. To address this question, this investigation compares the duration of enamel formation in Neandertals with that of three comparative modern human groups. Because dental and somatic growth are correlated with each other, dental growth periods are indicative of overall periods of growth. Growth increments on the anterior teeth of Neandertals, modern Inuit, and modern people from Newcastle and southern Africa were counted and their means compared. In addition, potential variation in the time spans represented by growth increments was considered and incorporated into the analysis of enamel formation times. These analyses show that Neandertal imbricational enamel formation times, although likely to have been faster than those of the Inuit, are not likely to have been faster than those of the Newcastle sample and for some teeth are clearly slower than those of the southern African sample. Thus, Neandertal tooth growth and, by extension, somatic growth, appears to be encompassed within the modern human range of interpopulation variation.", "keyphrases": ["tooth", "neandertals", "modern human"]}
{"id": "paleo.001912", "title": "The meaning of birth and death (in macroevolutionary birth\u2013death models)", "abstract": "Birth\u2013death models are central to much macroevolutionary theory. The fundamental parameters of these models concern durations. Different species concepts realize different species durations because they represent different ideas of what birth (speciation) and death (extinction) mean. Here, we use Cenozoic macroperforate planktonic foraminifera as a case study to ask: what are the dynamical consequences of changing the definition of birth and death? We show strong evidence for biotic constraints on diversification using evolutionary species, but less with morphospecies. Discussing reasons for this discrepancy, we emphasize that clarity of species concept leads to clarity of meaning when interpreting macroevolutionary birth\u2013death models.", "keyphrases": ["birth", "macroevolutionary birth\u2013death model", "parameter", "species concept", "evolutionary specie"]}
{"id": "paleo.012787", "title": "Empirical Evaluation of Bone Extraction Protocols", "abstract": "The application of high-resolution analytical techniques to characterize ancient bone proteins requires clean, efficient extraction to obtain high quality data. Here, we evaluated many different protocols from the literature on ostrich cortical bone and moa cortical bone to evaluate their yield and relative purity using the identification of antibody-antigen complexes on enzyme-linked immunosorbent assay and gel electrophoresis. Moa bone provided an ancient comparison for the effectiveness of bone extraction protocols tested on ostrich bone. For the immunological part of this study, we focused on collagen I, osteocalcin, and hemoglobin because collagen and osteocalcin are the most abundant proteins in the mineralized extracellular matrix and hemoglobin is common in the vasculature. Most of these procedures demineralize the bone first, and then the remaining organics are chemically extracted. We found that the use of hydrochloric acid, rather than ethylenediaminetetraacetic acid, for demineralization resulted in the cleanest extractions because the acid was easily removed. In contrast, the use of ethylenediaminetetraacetic acid resulted in smearing upon electrophoretic separation, possibly indicating these samples were not as pure. The denaturing agents sodium dodecyl sulfate, urea, and guanidine HCl have been used extensively for the solubilization of proteins in non-biomineralized tissue, but only the latter has been used on bone. We show that all three denaturing agents are effective for extracting bone proteins. One additional method tested uses ammonium bicarbonate as a solubilizing buffer that is more appropriate for post-extraction analyses (e.g., proteomics) by removing the need for desalting. We found that both guanidine HCl and ammonium bicarbonate were effective for extracting many bone proteins, resulting in similar electrophoretic patterns. With the increasing use of proteomics, a new generation of scientists are now interested in the study of proteins from not only extant bone but also from ancient bone.", "keyphrases": ["bone extraction protocol", "demineralization", "hydrochloric acid"]}
{"id": "10.1144/SP326.4", "title": "Late Proterozoic plate tectonics and palaeogeography: a tale of two supercontinents, Rodinia and Pannotia", "abstract": "Abstract The plate tectonic and palaeogeographic history of the late Proterozoic is a tale of two supercontinents: Rodinia and Pannotia. Rodinia formed during the Grenville Event (c. 1100 Ma) and remained intact until its collision with the Congo continent (800\u2013750 Ma). This collision closed the southern part of the Mozambique Seaway, and triggered the break-up of Rodinia. The Panthalassic Ocean opened as the supercontinent of Rodinia split into a northern half (East Gondwana, Cathyasia and Cimmeria) and a southern half (Laurentia, Amazonia\u2013NW Africa, Baltica, and Siberia). Over the next 150 Ma, North Rodinia rotated counter-clockwise over the North Pole, while South Rodinia rotated clockwise across the South Pole. In the latest Precambrian (650\u2013550 Ma), the three Neoproterozoic continents \u2013 North Rodinia, South Rodinia and the Congo continents \u2013 collided during the Pan-Africa Event forming the second Neoproterozoic supercontinent, Pannotia (Greater Gondwanaland). Pan-African mountain building and the fall in sea level associated with the assembly of Pannotia may have triggered the extreme Ice House conditions that characterize the middle and late Neoproterozoic. Although the palaeogeographic maps presented here do not prohibit a Snowball Earth, the mapped extent of Neoproterozoic ice sheets favour a bipolar Ice House World with a broad expanse of ocean at the equator. Soon after it was assembled (c. 560 Ma), Pannotia broke apart into the four principal Palaeozoic continents: Laurentia (North America), Baltica (northern Europe), Siberia and Gondwana. The amalgamation and subsequent break-up of Pannotia may have triggered the \u2018Cambrian Explosion\u2019. The first economically important accumulations of hydrocarbons are from Neoproterozoic sources. The two major source rocks of this age (Nepa of Siberia and Huqf of Oman) occur in association with massive Neoproterozoic evaporite deposits and in the warm equatorial\u2013subtropical belt, within 30\u00b0 of the equator.", "keyphrases": ["tale", "supercontinent", "rodinia"]}
{"id": "paleo.005404", "title": "Shell structure of helically coiled microconchids from the Middle Triassic (Anisian) of Germany", "abstract": "Microconchid affinity of helically coiled tubes of Microconchus aberrans (Hohenstein, 1913) from the early Anisian of southern Germany is supported by an SEM study of shell structure. There are probable pseudopunctae in the shell of M. aberrans. Helically coiled and some substrate-cemented planispiral microconchids have similar microlamellar tube structures in the Triassic. The structure of the morphologically aberrant M. aberrans is characteristic of Palaeozoic to Middle Triassic microconchids. Allochthonous tube fragments of M. aberrans in the Wellenkalk presumably originate from a microconchid biostrome.", "keyphrases": ["microconchid", "triassic", "germany", "shell structure"]}
{"id": "paleo.005637", "title": "A new turtle from the La Colonia Formation (Campanian\u2013Maastrichtian), Patagonia, Argentina, with remarks on the evolution of the vertebral column in turtles", "abstract": "Abstract:\u2002 Patagoniaemys gasparinae gen. et sp. nov. is a new stem turtle found in central Patagonia, Chubut Province, Argentina, in outcrops of the La Colonia Formation (Campanian\u2013Maastrichtian). This is a turtle of relatively large size (carapace length c. 70\u2003cm), and the preserved remains of the holotype consist of skull fragments and several postcranial elements including a nearly complete vertebral column. A phylogenetic analysis shows Patagoniaemys gasparinae gen. et sp. nov. forming a monophyletic group with Otwayemys cunicularius and Mongolochelys efremovi, as a sister group to Meiolaniidae. A comprehensive review confirms that formed cervical vertebrae appeared independently several times during turtle evolution: in the clade that includes Patagoniaemys gasparinae gen. et sp. nov. and Meiolaniidae, in some baenids, in the total group Pleurodira and in crown group Cryptodira. Likewise, formed caudal vertebrae appeared several times in turtle evolution.", "keyphrases": ["turtle", "campanian\u2013maastrichtian", "vertebral column", "mongolochelys efremovi"]}
{"id": "paleo.004601", "title": "Brief oxygenation events in locally anoxic oceans during the Cambrian solves the animal breathing paradox", "abstract": "Oxygen is a prerequisite for all large and motile animals. It is a puzzling paradox that fossils of benthic animals are often found in black shales with geochemical evidence for deposition in marine environments with anoxic and sulfidic bottom waters. It is debated whether the geochemical proxies are unreliable, affected by diagenesis, or whether the fossils are transported from afar or perhaps were not benthic. Here, we improved the stratigraphic resolution of marine anoxia records 100\u20131000 fold using core-scanning X-Ray Fluorescence and established a centennial resolution record of oxygen availability at the seafloor in an epicontinental sea that existed ~501\u2013494 million years ago. The study reveals that anoxic bottom-water conditions, often with toxic hydrogen sulfide present, were interrupted by brief oxygenation events of 600\u20133000 years duration, corresponding to 1\u20135 mm stratigraphic thickness. Fossil shells occur in some of these oxygenated intervals suggesting that animals invaded when conditions permitted an aerobic life style at the seafloor. Although the fauna evidently comprised opportunistic species adapted to low oxygen environments, these findings reconcile a long-standing debate between paleontologists and geochemists, and shows the potential of ultra-high resolution analyses for reconstructing redox conditions in past oceans.", "keyphrases": ["ocean", "shale", "brief oxygenation event"]}
{"id": "paleo.012393", "title": "Enamel Ultrastructure in Fossil Cetaceans (Cetacea: Archaeoceti and Odontoceti)", "abstract": "The transition from terrestrial ancestry to a fully pelagic life profoundly altered the body systems of cetaceans, with extreme morphological changes in the skull and feeding apparatus. The Oligocene Epoch was a crucial time in the evolution of cetaceans when the ancestors of modern whales and dolphins (Neoceti) underwent major diversification, but details of dental structure and evolution are poorly known for the archaeocete-neocete transition. We report the morphology of teeth and ultrastructure of enamel in archaeocetes, and fossil platanistoids and delphinoids, ranging from late Oligocene (Waitaki Valley, New Zealand) to Pliocene (Caldera, Chile). Teeth were embedded in epoxy resin, sectioned in cross and longitudinal planes, polished, etched, and coated with gold palladium for scanning electron microscopy (SEM) observation. SEM images showed that in archaeocetes, squalodontids and Prosqualodon (taxa with heterodont and nonpolydont/limited polydont teeth), the inner enamel was organized in Hunter-Schreger bands (HSB) with an outer layer of radial enamel. This is a common pattern in most large-bodied mammals and it is regarded as a biomechanical adaptation related to food processing and crack resistance. Fossil Otekaikea sp. and delphinoids, which were polydont and homodont, showed a simpler structure, with inner radial and outer prismless enamel. Radial enamel is regarded as more wear-resistant and has been retained in several mammalian taxa in which opposing tooth surfaces slide over each other. These observations suggest that the transition from a heterodont and nonpolydont/limited polydont dentition in archaeocetes and early odontocetes, to homodont and polydont teeth in crownward odontocetes, was also linked to a marked simplification in the enamel Schmelzmuster. These patterns probably reflect functional shifts in food processing from shear-and-mastication in archaeocetes and early odontocetes, to pierce-and-grasp occlusion in crownward odontocetes, with the implication of less demanding feeding biomechanics as seen in most extant odontocetes.", "keyphrases": ["cetacea", "archaeocete", "fossil platanistoid", "enamel ultrastructure"]}
{"id": "paleo.010899", "title": "Multiple hominin dispersals into Southwest Asia over the past 400,000 years", "abstract": "Pleistocene hominin dispersals out of, and back into, Africa necessarily involved traversing the diverse and often challenging environments of Southwest Asia1\u20134. Archaeological and palaeontological records from the Levantine woodland zone document major biological and cultural shifts, such as alternating occupations by Homo sapiens and Neanderthals. However, Late Quaternary cultural, biological and environmental records from the vast arid zone that constitutes most of Southwest Asia remain scarce, limiting regional-scale insights into changes in hominin demography and behaviour1,2,5. Here we report a series of dated palaeolake sequences, associated with stone tool assemblages and vertebrate fossils, from the Khall Amayshan 4 and Jubbah basins in the Nefud Desert. These findings, including the oldest dated hominin occupations in Arabia, reveal at least five hominin expansions into the Arabian interior, coinciding with brief \u2018green\u2019 windows of reduced aridity approximately 400, 300, 200, 130\u201375 and 55 thousand years ago. Each occupation phase is characterized by a distinct form of material culture, indicating colonization by diverse hominin groups, and a lack of long-term Southwest Asian population continuity. Within a general pattern of African and Eurasian hominin groups being separated by Pleistocene Saharo-Arabian aridity, our findings reveal the tempo and character of climatically modulated windows for dispersal and admixture.", "keyphrases": ["dispersal", "southwest asia", "africa"]}
{"id": "10.1073/pnas.1211526110", "title": "Mass extinction of lizards and snakes at the Cretaceous\u2013Paleogene boundary", "abstract": "The Cretaceous\u2013Paleogene (K-Pg) boundary is marked by a major mass extinction, yet this event is thought to have had little effect on the diversity of lizards and snakes (Squamata). A revision of fossil squamates from the Maastrichtian and Paleocene of North America shows that lizards and snakes suffered a devastating mass extinction coinciding with the Chicxulub asteroid impact. Species-level extinction was 83%, and the K-Pg event resulted in the elimination of many lizard groups and a dramatic decrease in morphological disparity. Survival was associated with small body size and perhaps large geographic range. The recovery was prolonged; diversity did not approach Cretaceous levels until 10 My after the extinction, and resulted in a dramatic change in faunal composition. The squamate fossil record shows that the end-Cretaceous mass extinction was far more severe than previously believed, and underscores the role played by mass extinctions in driving diversification.", "keyphrases": ["snake", "north america", "mass extinction"]}
{"id": "paleo.011620", "title": "The origin of heredity in protocells", "abstract": "Here we develop a computational model that examines one of the first major biological innovations\u2014the origin of heredity in simple protocells. The model assumes that the earliest protocells were autotrophic, producing organic matter from CO2 and H2. Carbon fixation was facilitated by geologically sustained proton gradients across fatty acid membranes, via iron\u2013sulfur nanocrystals lodged within the membranes. Thermodynamic models suggest that organics formed this way should include amino acids and fatty acids. We assume that fatty acids partition to the membrane. Some hydrophobic amino acids chelate FeS nanocrystals, producing three positive feedbacks: (i) an increase in catalytic surface area; (ii) partitioning of FeS nanocrystals to the membrane; and (iii) a proton-motive active site for carbon fixing that mimics the enzyme Ech. These positive feedbacks enable the fastest-growing protocells to dominate the early ecosystem through a simple form of heredity. We propose that as new organics are produced inside the protocells, the localized high-energy environment is more likely to form ribonucleotides, linking RNA replication to its ability to drive protocell growth from the beginning. Our novel conceptualization sets out conditions under which protocell heredity and competition could arise, and points to where crucial experimental work is required. This article is part of the themed issue \u2018Process and pattern in innovations from cells to societies\u2019.", "keyphrases": ["heredity", "protocell", "organic", "matter", "environment"]}
{"id": "10.1098/rspb.2006.0229", "title": "Early Tertiary mammals from North Africa reinforce the molecular Afrotheria clade", "abstract": "The phylogenetic pattern and timing of the radiation of mammals, especially the geographical origins of major crown clades, are areas of controversy among molecular biologists, morphologists and palaeontologists. Molecular phylogeneticists have identified an Afrotheria clade, which includes several taxa as different as tenrecs (Tenrecidae), golden moles (Chrysochloridae), elephant-shrews (Macroscelididae), aardvarks (Tubulidentata) and paenungulates (elephants, sea cows and hyracoids). Molecular data also suggest a Cretaceous African origin for Afrotheria within Placentalia followed by a long period of endemic evolution on the Afro-Arabian continent after the mid-Cretaceous Gondwanan breakup (approx. 105\u201325\u200aMyr ago). However, there was no morphological support for such a natural grouping so far. Here, we report new dental and postcranial evidence of Eocene stem hyrax and macroscelidid from North Africa that, for the first time, provides a congruent phylogenetic view with the molecular Afrotheria clade. These new fossils imply, however, substantial changes regarding the historical biogeography of afrotheres. Their long period of isolation in Africa, as assumed by molecular inferences, is now to be reconsidered inasmuch as Eocene paenungulates and elephant-shrews are here found to be related to some Early Tertiary Euramerican \u2018hyopsodontid condylarths\u2019 (archaic hoofed mammals). As a result, stem members of afrotherian clades are not strictly African but also include some Early Paleogene Holarctic mammals.", "keyphrases": ["north africa", "afrotheria clade", "golden mole"]}
{"id": "10.1002/ajpa.20870", "title": "Isotopic and dental evidence for infant and young child feeding practices in an imperial Roman skeletal sample.", "abstract": "This study integrates isotopic, palaeopathological, and historical evidence to investigate infant and young child feeding practices in a Roman period (1st to 3rd centuries AD) skeletal sample from the Isola Sacra necropolis (Rome, Italy). Stable isotope analysis of bone collagen from 37 rib samples indicates that transitional feeding began by the end of the first year and weaning occurred by 2-2.5 years of age. Both delta(15)N and delta(13)C data clearly show the trophic level effect associated with breastfeeding. Childhood diet is investigated using dental pathology data in the deciduous dentitions of 78 individuals aged between 1 and 12 years. The presence of calculus, caries, and tooth wear in young children suggests that individuals were provided complementary foods and other items that impacted their dental health at an early age. The isotopic and dental data are generally consistent with the historical evidence from the Roman period with respect to the general timetable of weaning and the character of complementary foods. This is the first study to integrate isotopic and deciduous dental pathology data to explore infant and young child feeding practices in the Roman world.", "keyphrases": ["infant", "child feeding practice", "skeletal sample", "food"]}
{"id": "paleo.001200", "title": "Head and Neck Posture in Sauropod Dinosaurs Inferred from Extant Animals", "abstract": "The neck posture of sauropod dinosaurs has long been controversial. Recent reconstructions position the cervical vertebrae and skull in an \u201costeological neutral pose\u201d (ONP), the best fit arrived at by articulating the vertebrae with the zygapophyses in maximum contact. This approach in isolation suggests that most or all sauropods held their necks horizontally. However, a substantial literature on extant amniotes (mammals, turtles, squamates, crocodilians and birds) shows that living animals do not habitually maintain their necks in ONP. Instead, the neck is maximally extended and the head is maximally flexed, so that the mid-cervical region is near vertical. Unless sauropods behaved differently from all extant amniote groups, they must have habitually held their necks extended and their heads flexed. The life orientation of the heads of sauropods has been inferred from the inclination of the semi-circular canals. However, extant animals show wide variation in inclination of the \u201chorizontal\u201d semi-circular canal: the orientation of this structure is not tightly constrained and can give only a general idea of the life posture of extinct animals' heads.", "keyphrases": ["neck posture", "extant animal", "osteological neutral pose", "amniote", "head"]}
{"id": "paleo.007968", "title": "Reexamination of the Mandibular and Dental Morphology of the Early Jurassic Mammaliaform Hadrocodium wui", "abstract": "Reexamination of the mandibular and dental morphology of the Early Jurassic mammaliaform Hadrocodium wui. CT visualization of the mandible and dentition of Hadrocodium wui , a stem mammaliaform from the Lower Jurassic Lower Lufeng Formation of Yunnan, China has revealed new features not accessible by previous microscopic study of the fossil. Its mandible shows a postdentary trough with an overhanging medial ridge and a short Meckel\u2019s sulcus. An incomplete part of the ectotympanic and possibly a remnant of Meckel\u2019s element are preserved in the postdentary trough. Thus, Hadrocodium is similar to other mammaliaforms in retaining a mandibular middle ear, contrary to our earlier interpretation. The mandible exhibits a large postcanine diastema from shedding of anterior premolars without replacement, an age-dependent feature better developed in older adults. Another adult feature is the alignment of the ultimate molar to the coronoid process. This is consistent with age-dependent changes in other mammaliaforms where the last molars of the toothrow shift from medial of the coronoid process in the juvenile, to a position in front of the coronoid process in the adult. The mandible has a short mobile symphysis. The dentition consists of I5, C1 (two-rooted), P3 (including P1 position) and M2 (M2 with confluent roots), and i4, c1 (partially two-rooted), p3, and m2 (m2 with partially confluent roots). The two-rooted upper canines are more derived than other Early Jurassic mammaliaforms from the same fauna, although similar to docodontans. Hadrocodium is unique in that the lower m2 cusp a occludes in the embrasure between upper M1\u2013M2, but the posterior part of m2 shows between-cusp occlusion with upper M2 main cusp A. M2 is half the size of the lower m2, and occludes only with the distal half of m2. The upper postcanines show a steep gradient of posteriorly decreasing tooth size, more so than other mammaliaforms. The CT examination corroborates that there are no unerupted teeth in the upper or lower jaws, and the holotype of H. wui is dentally and osteologically mature and capable of independent feeding.", "keyphrases": ["dental morphology", "hadrocodium wui", "reexamination"]}
{"id": "paleo.012988", "title": "Paleomicrobiology: Revealing Fecal Microbiomes of Ancient Indigenous Cultures", "abstract": "Coprolites are fossilized feces that can be used to provide information on the composition of the intestinal microbiota and, as we show, possibly on diet. We analyzed human coprolites from the Huecoid and Saladoid cultures from a settlement on Vieques Island, Puerto Rico. While more is known about the Saladoid culture, it is believed that both societies co-existed on this island approximately from 5 to 1170 AD. By extracting DNA from the coprolites, followed by metagenomic characterization, we show that both cultures can be distinguished from each other on the basis of their bacterial and fungal gut microbiomes. In addition, we show that parasite loads were heavy and also culturally distinct. Huecoid coprolites were characterized by maize and Basidiomycetes sequences, suggesting that these were important components of their diet. Saladoid coprolite samples harbored sequences associated with fish parasites, suggesting that raw fish was a substantial component of their diet. The present study shows that ancient DNA is not entirely degraded in humid, tropical environments, and that dietary and/or host genetic differences in ancient populations may be reflected in the composition of their gut microbiome. This further supports the hypothesis that the two ancient cultures studied were distinct, and that they retained distinct technological/cultural differences during an extended period of close proximity and peaceful co-existence. The two populations seemed to form the later-day Ta\u00ednos, the Amerindians present at the point of Columbian contact. Importantly, our data suggest that paleomicrobiomics can be a powerful tool to assess cultural differences between ancient populations.", "keyphrases": ["ancient indigenous culture", "coprolite", "dna"]}
{"id": "10.1089/ast.2005.5.333", "title": "Raman imagery: a new approach to assess the geochemical maturity and biogenicity of permineralized precambrian fossils.", "abstract": "Laser-Raman imagery is a non-intrusive, non-destructive analytical technique, recently introduced to Precambrian paleobiology, that can be used to demonstrate a one-to-one spatial correlation between the optically discernible morphology and kerogenous composition of permineralized fossil microorganisms. Made possible by the submicron-scale resolution of the technique and its high sensitivity to the Raman signal of carbonaceous matter, such analyses can be used to determine the chemical-structural characteristics of organic-walled microfossils and associated sapropelic carbonaceous matter in acid-resistant residues and petrographic thin sections. Here we use this technique to analyze kerogenous microscopic fossils and associated carbonaceous sapropel permineralized in 22 unmetamorphosed or little-metamorphosed fine-grained chert units ranging from approximately 400 to approximately 2,100 Ma old. The lineshapes of the Raman spectra acquired vary systematically with five indices of organic geochemical maturation: (1) the mineral-based metamorphic grade of the fossil-bearing units; (2) the fidelity of preservation of the fossils studied; (3) the color of the organic matter analyzed; and both the (4) H/C and (5) N/C ratios measured in particulate kerogens isolated from bulk samples of the fossil-bearing cherts. Deconvolution of relevant spectra shows that those of relatively well-preserved permineralized kerogens analyzed in situ exhibit a distinctive set of Raman bands that are identifiable also in hydrated organic-walled microfossils and particulate carbonaceous matter freed from the cherts by acid maceration. These distinctive Raman bands, however, become indeterminate upon dehydration of such specimens. To compare quantitatively the variations observed among the spectra measured, we introduce the Raman Index of Preservation, an approximate measure of the geochemical maturity of the kerogens studied that is consistent both with the five indices of organic geochemical alteration and with spectra acquired from fossils experimentally heated under controlled laboratory conditions. The results reported provide new insight into the chemical-structural characteristics of ancient carbonaceous matter, the physicochemical changes that accompany organic geochemical maturation, and a new criterion to be added to the suite of evidence by which to evaluate the origin of minute fossil-like objects of possible but uncertain biogenicity.", "keyphrases": ["geochemical maturity", "biogenicity", "kerogen"]}
{"id": "10.1306/13331504M983503", "title": "The Great American Carbonate Bank in Eastern Canada: An Overview", "abstract": "The postrifted margin of Laurentia in eastern Canada had a rugged paleomorphology, with major salients and recesses formed during the long-lasting (Ediacaran to late Early Cambrian) breakup of Rodinia. After short-lived carbonate production during the Early Cambrian, the great American carbonate bank (GACB) was firmly established in the earliest Middle Cambrian as the last rift-related event (Hawke Bay event, late Early Cambrian), and was followed by mostly passive thermal subsidence of the continental crust of Laurentia. Middle to Upper Cambrian carbonates are well preserved in the Port au Port Group in western Newfoundland (St. Lawrence promontory). Scattered outcrops of upper Middle to Upper Cambrian sedimentary rocks are found in southern and eastern Quebec (Quebec reentrant), although most of the preserved Upper Cambrian facies in the reentrant consist of nearshore to fluvial clastics unconformably overlying the Grenvillian basement. The Cambrian shallow-marine carbonates are dominated by high-energy facies with significant thrombolite reefs at the platform margin. The succession consists of large-scale transgressive-regressive cycles known as Cambrian grand cycles. Some anomalies in stacking patterns are suggestive of local tectonic events that were hypothesized based on the nature (facies and age) of carbonate clasts that accumulated on the continental slope. The Cambrian\u2013Ordovician transition occurred at a time of a major sea level lowstand that resulted in a significant unconformity in southern Quebec and Ontario. In western Newfoundland, this sea level fall is recorded in the regressive facies of the last Cambrian grand cycle but did not culminate in subaerial exposure. The duration of the depositional hiatus at the Cambrian\u2013Ordovician transition increases toward the west from an early Skullrockian gap in the Philipsburg thrust slice in southeastern Quebec; the hiatus covered the entire Skullrockian in eastern Ontario. A major sea level rise at or near the base of the Ordovician resulted in sedimentation on an extensive peritidal, mud-dominated, low-energy carbonate platform. This platform is known as the St. George Group (western Newfoundland), the Beekmantown Group (southwestern Quebec and Ontario), the School House Hill Group (southeastern Quebec), and the Romaine Formation (Anticosti Island). The carbonate facies are characterized by large- and small-scale depositional cycles. Two third-order cycles are well documented in western Newfoundland. The presence of such cycles is also proposed farther south, although their precise character still has to be documented. Multiple fifth-order meter-scale peritidal-dominated cycles have been documented in the Lower Ordovician carbonates. A diachronous change in depositional style occurred along the margin of Laurentia near the base of the Middle Ordovician. Facies patterns became controlled by faulting and accumulation rates increased significantly. These changes occurred first in the late Ibexian in southeastern Quebec and in the early Whiterockian elsewhere. At most localities, this transition is also expressed in a significant subaerial unconformity that is recognized along the entire eastern (paleosouthern) margin of Laurentia. This subaerial event is interpreted as resulting from lithosphere upwarping in front of the migrating Taconic orogenic wedge. The west-directed migration of the tectonic peripheral bulge resulted in the final destruction of the GACB as sedimentation resumed in a tectonically active foreland basin.", "keyphrases": ["american carbonate bank", "eastern canada", "unconformity", "succession"]}
{"id": "paleo.010834", "title": "Estimating Mass Properties of Dinosaurs Using Laser Imaging and 3D Computer Modelling", "abstract": "Body mass reconstructions of extinct vertebrates are most robust when complete to near-complete skeletons allow the reconstruction of either physical or digital models. Digital models are most efficient in terms of time and cost, and provide the facility to infinitely modify model properties non-destructively, such that sensitivity analyses can be conducted to quantify the effect of the many unknown parameters involved in reconstructions of extinct animals. In this study we use laser scanning (LiDAR) and computer modelling methods to create a range of 3D mass models of five specimens of non-avian dinosaur; two near-complete specimens of Tyrannosaurus rex, the most complete specimens of Acrocanthosaurus atokensis and Strutiomimum sedens, and a near-complete skeleton of a sub-adult Edmontosaurus annectens. LiDAR scanning allows a full mounted skeleton to be imaged resulting in a detailed 3D model in which each bone retains its spatial position and articulation. This provides a high resolution skeletal framework around which the body cavity and internal organs such as lungs and air sacs can be reconstructed. This has allowed calculation of body segment masses, centres of mass and moments or inertia for each animal. However, any soft tissue reconstruction of an extinct taxon inevitably represents a best estimate model with an unknown level of accuracy. We have therefore conducted an extensive sensitivity analysis in which the volumes of body segments and respiratory organs were varied in an attempt to constrain the likely maximum plausible range of mass parameters for each animal. Our results provide wide ranges in actual mass and inertial values, emphasizing the high level of uncertainty inevitable in such reconstructions. However, our sensitivity analysis consistently places the centre of mass well below and in front of hip joint in each animal, regardless of the chosen combination of body and respiratory structure volumes. These results emphasize that future biomechanical assessments of extinct taxa should be preceded by a detailed investigation of the plausible range of mass properties, in which sensitivity analyses are used to identify a suite of possible values to be tested as inputs in analytical models.", "keyphrases": ["body mass", "sensitivity analysis", "volume", "uncertainty"]}
{"id": "10.1073/pnas.1604787113", "title": "Earliest land plants created modern levels of atmospheric oxygen", "abstract": "Significance The rise of atmospheric oxygen over Earth\u2019s history has received much recent interdisciplinary attention. However, the puzzle of when and how atmospheric oxygen reached modern levels remains unresolved. Many recent studies have argued for a major oxygenation event\u2014of uncertain cause\u2014in the Neoproterozoic Era >541 Ma, enabling the rise of animals. Previous modelling work has predicted a late Paleozoic oxygen rise (<380 Ma) due to the rise of forests. Here we show that neither scenario is correct. Instead, the earliest plants, which colonized the land from 470 Ma onward, first increased atmospheric oxygen to present levels by 400 Ma, and this instigated fire-mediated feedbacks that have stabilized high oxygen levels ever since, shaping subsequent evolution. The progressive oxygenation of the Earth\u2019s atmosphere was pivotal to the evolution of life, but the puzzle of when and how atmospheric oxygen (O2) first approached modern levels (\u223c21%) remains unresolved. Redox proxy data indicate the deep oceans were oxygenated during 435\u2013392 Ma, and the appearance of fossil charcoal indicates O2 >15\u201317% by 420\u2013400 Ma. However, existing models have failed to predict oxygenation at this time. Here we show that the earliest plants, which colonized the land surface from \u223c470 Ma onward, were responsible for this mid-Paleozoic oxygenation event, through greatly increasing global organic carbon burial\u2014the net long-term source of O2. We use a trait-based ecophysiological model to predict that cryptogamic vegetation cover could have achieved \u223c30% of today\u2019s global terrestrial net primary productivity by \u223c445 Ma. Data from modern bryophytes suggests this plentiful early plant material had a much higher molar C:P ratio (\u223c2,000) than marine biomass (\u223c100), such that a given weathering flux of phosphorus could support more organic carbon burial. Furthermore, recent experiments suggest that early plants selectively increased the flux of phosphorus (relative to alkalinity) weathered from rocks. Combining these effects in a model of long-term biogeochemical cycling, we reproduce a sustained +2\u2030 increase in the carbonate carbon isotope (\u03b413C) record by \u223c445 Ma, and predict a corresponding rise in O2 to present levels by 420\u2013400 Ma, consistent with geochemical data. This oxygen rise represents a permanent shift in regulatory regime to one where fire-mediated negative feedbacks stabilize high O2 levels.", "keyphrases": ["modern level", "atmospheric oxygen", "bryophyte", "early plant", "rock"]}
{"id": "paleo.011759", "title": "Kretzoiarctos gen. nov., the Oldest Member of the Giant Panda Clade", "abstract": "The phylogenetic position of the giant panda, Ailuropoda melanoleuca (Carnivora: Ursidae: Ailuropodinae), has been one of the most hotly debated topics by mammalian biologists and paleontologists during the last century. Based on molecular data, it is currently recognized as a true ursid, sister-taxon of the remaining extant bears, from which it would have diverged by the Early Miocene. However, from a paleobiogeographic and chronological perspective, the origin of the giant panda lineage has remained elusive due to the scarcity of the available Miocene fossil record. Until recently, the genus Ailurarctos from the Late Miocene of China (ca. 8\u20137 mya) was recognized as the oldest undoubted member of the Ailuropodinae, suggesting that the panda lineage might have originated from an Ursavus ancestor. The role of the purported ailuropodine Agriarctos, from the Miocene of Europe, in the origins of this clade has been generally dismissed due to the paucity of the available material. Here, we describe a new ailuropodine genus, Kretzoiarctos gen. nov., based on remains from two Middle Miocene (ca. 12\u201311 Ma) Spanish localities. A cladistic analysis of fossil and extant members of the Ursoidea confirms the inclusion of the new genus into the Ailuropodinae. Moreover, Kretzoiarctos precedes in time the previously-known, Late Miocene members of the giant panda clade from Eurasia (Agriarctos and Ailurarctos). The former can be therefore considered the oldest recorded member of the giant panda lineage, which has significant implications for understanding the origins of this clade from a paleobiogeographic viewpoint.", "keyphrases": ["giant panda clade", "ailuropoda", "carnivora", "agriarctos", "kretzoiarctos"]}
{"id": "paleo.008635", "title": "Geology and lithology of the Tagay-1 section at Olkhon Island (Lake Baikal, Eastern Siberia), and description of Aplodontidae, Mylagaulidae and Sciuridae (Rodentia, Mammalia)", "abstract": "Excavations along the Tagay-1 section shed light into the composition of small mammal assemblages of the Tagay site. The present paper focuses on the geology and geomorphology of Olkhon Island, the lithology and fossil evidence along the Tagay-1 section and descriptions of the aplodontid, mylagaulid and sciurid rodents. The described fossils are isolated teeth of four taxa, Ansomys sp. (Aplodontidae), Lamugaulus olkhonensis Tesakov and Lopatin, 2015 (Mylagaulidae), Sciuridae indet. and Spermophilinus debruijni nov. spec. (Sciuridae). The archaic tooth pattern of these rodents suggests an age around the Early/ Middle Miocene transition.", "keyphrases": ["olkhon island", "mylagaulidae", "geology", "fossil collection", "lagomorpha"]}
{"id": "paleo.012896", "title": "First bone-cracking dog coprolites provide new insight into bone consumption in Borophagus and their unique ecological niche", "abstract": "Borophagine canids have long been hypothesized to be North American ecological \u2018avatars\u2019 of living hyenas in Africa and Asia, but direct fossil evidence of hyena-like bone consumption is hitherto unknown. We report rare coprolites (fossilized feces) of Borophagus parvus from the late Miocene of California and, for the first time, describe unambiguous evidence that these predatory canids ingested large amounts of bone. Surface morphology, micro-CT analyses, and contextual information reveal (1) droppings in concentrations signifying scent-marking behavior, similar to latrines used by living social carnivorans; (2) routine consumption of skeletons; (3) undissolved bones inside coprolites indicating gastrointestinal similarity to modern striped and brown hyenas; (4) B. parvus body weight of ~24 kg, reaching sizes of obligatory large-prey hunters; and (5) prey size ranging ~35\u2013100 kg. This combination of traits suggests that bone-crushing Borophagus potentially hunted in collaborative social groups and occupied a niche no longer present in North American ecosystems.", "keyphrases": ["bone consumption", "borophagus", "ecosystem"]}
{"id": "10.1080/02724634.2018.1525390", "title": "Late Pleistocene Glyptodontinae (Mammalia, Xenarthra, Glyptodontidae) from southern South America: a comprehensive review", "abstract": "ABSTRACT Glyptodon Owen is one of the most frequently recorded glyptodonts in the Pleistocene of South America, especially between 20\u00b0S and 38\u00b0S. A high specific diversity has traditionally been proposed for the genus, including some species of assumed biostratigraphic importance (e.g., G. perforatus and G. clavipes). However, most of these species are poorly characterized, and the morphological variability in the different regions of the dorsal carapace has not been considered. Recent reviews have indicated that its diversity was lower than previously supposed, particularly in the late Pleistocene. In this scenario, this contribution aims to (1) review the late Pleistocene Glyptodon species from southern South America and (2) discuss the primary aspects of the geographic and chronological distribution of the species that are deemed as valid. Morphological and morphometric analyses indicate that the diversity in the late Pleistocene of southern South America is reduced to a single well-characterized species, G. reticulatus Owen. This species is recorded in MIS 3 and MIS 2 and is distributed in the Pampean, Mesopotamian, and north-central regions of Argentina, southern Bolivia, and Uruguay (\u223c20\u00b0S\u201338\u00b0S). In summary, the diversity of Glyptodontinae in the Pleistocene of southern South America was limited to two well-characterized species: G. munizi in the early\u2013middle Pleistocene and G. reticulatus in the late Pleistocene\u2013early Holocene.", "keyphrases": ["southern south america", "review", "glyptodon owen"]}
{"id": "10.1017/RDC.2020.41", "title": "The IntCal20 Northern Hemisphere Radiocarbon Age Calibration Curve (0\u201355 cal kBP)", "abstract": "ABSTRACT Radiocarbon (14C) ages cannot provide absolutely dated chronologies for archaeological or paleoenvironmental studies directly but must be converted to calendar age equivalents using a calibration curve compensating for fluctuations in atmospheric 14C concentration. Although calibration curves are constructed from independently dated archives, they invariably require revision as new data become available and our understanding of the Earth system improves. In this volume the international 14C calibration curves for both the Northern and Southern Hemispheres, as well as for the ocean surface layer, have been updated to include a wealth of new data and extended to 55,000 cal BP. Based on tree rings, IntCal20 now extends as a fully atmospheric record to ca. 13,900 cal BP. For the older part of the timescale, IntCal20 comprises statistically integrated evidence from floating tree-ring chronologies, lacustrine and marine sediments, speleothems, and corals. We utilized improved evaluation of the timescales and location variable 14C offsets from the atmosphere (reservoir age, dead carbon fraction) for each dataset. New statistical methods have refined the structure of the calibration curves while maintaining a robust treatment of uncertainties in the 14C ages, the calendar ages and other corrections. The inclusion of modeled marine reservoir ages derived from a three-dimensional ocean circulation model has allowed us to apply more appropriate reservoir corrections to the marine 14C data rather than the previous use of constant regional offsets from the atmosphere. Here we provide an overview of the new and revised datasets and the associated methods used for the construction of the IntCal20 curve and explore potential regional offsets for tree-ring data. We discuss the main differences with respect to the previous calibration curve, IntCal13, and some of the implications for archaeology and geosciences ranging from the recent past to the time of the extinction of the Neanderthals.", "keyphrases": ["intcal20", "calibration curve", "tree ring", "marine20"]}
{"id": "paleo.008095", "title": "Digital reconstruction of the Ceprano calvarium (Italy), and implications for its interpretation", "abstract": "The Ceprano calvarium was discovered in fragments on March 1994 near the town of Ceprano in southern Latium (Italy), embedded in Middle Pleistocene layers. After reconstruction, its morphological features suggests that the specimen belongs to an archaic variant of H. heidelbergensis, representing a proxy for the last common ancestor of the diverging clades that respectively led to H. neanderthalensis and H. sapiens. Unfortunately, the calvarium was taphonomically damaged. The postero-lateral vault, in particular, appears deformed and this postmortem damage may have influenced previous interpretations. Specifically, there is a depression on the fragmented left parietal, while the right cranial wall is warped and angulated. This deformation affected the shape of the occipital squama, producing an inclination of the transverse occipital torus. In this paper, after X-ray microtomography (\u03bcCT) of both the calvarium and several additional fragments, we analyze consistency and pattern of the taphonomic deformation that affected the specimen, before the computer-assisted retrodeformation has been performed; this has also provided the opportunity to reappraise early attempts at restoration. As a result, we offer a revised interpretation for the Ceprano calvarium\u2019s original shape, now free from the previous uncertainties, along with insight for its complex depositional and taphonomic history.", "keyphrases": ["ceprano calvarium", "italy", "restoration"]}
{"id": "paleo.001075", "title": "Conicocassis, a new genus of Arcellinina (testate lobose amoebae)", "abstract": "Superfamily Arcellinina (informally known as thecamoebians or testate lobose amoebae) are a group of shelled benthic protists common in most Quaternary lacustrine sediments. They are found worldwide, from the equator to the poles, living in a variety of fresh to brackish aquatic and terrestrial habitats. More than 130 arcellininid species and strains are ascribed to the genus Centropyxis Stein, 1857 within the family Centropyxidae Jung, 1942, which includes species that are distinguished by having a dorsoventral-oriented and flattened beret-like test (shell). Conicocassis, a new arcellininid genus of Centropyxidae differs from other genera of the family, specifically genus Centropyxis and its type species C. aculeata (Ehrenberg, 1932), by having a unique test comprised of two distinct components; a generally ovoid to subspherical, dorsoventral-oriented test body, with a pronounced asymmetrically positioned, funnellike flange extending from a small circular aperture. The type species of the new genus, Conicocassis pontigulasiformis (Beyens et al., 1986) has previously been reported from peatlands in Germany, the Netherlands and Austria, as well as very wet mosses and aquatic environments in High Arctic regions of Europe and North America. The occurrence of the species in lacustrine environments in the central Northwest Territories extends the known geographic distribution of the genus in North America considerably southward.", "keyphrases": ["new genus", "testate lobose amoebae", "equator", "terrestrial habitat", "conicocassis"]}
{"id": "paleo.000645", "title": "NEW METHODS TO DOCUMENT FOSSILS FROM LITHOGRAPHIC LIMESTONES OF SOUTHERN GERMANY AND LEBANON", "abstract": "We present different documentation methods tested on fossil specimens from Solnhofen-type lithographic limestones (Upper Jurassic, southern Germany) and from the related deposits from the Upper Cretaceous of Lebanon. One of the principles is composite imaging. This combines image fusion, i.e., coalescing several images of the same area but at different focal planes, resulting in a single image of high depth of field, and image stitching, i.e., combining fused images of several areas to a high resolution image of the complete specimen. The basis for the composite images can be normal light images, but most fossils from Solnhofen-type lithographic limestones are autofluorescent under UV light such that UV-fluorescence images can be equally well applied. In this context, we report a new fluorescence type for specimens not showing good UV fluorescence, i.e., those from the Zandt lagerst\u00e4tte or some from Lebanon. These specimens fluoresce orange when exposed to green light. Specimens from Lebanon exhibiting green-orange fluorescence have been documented under a confocal laser scanning microscope (cLSM). Fossils showing a relatively high relief can be documented with stereo images; based on these surfaces, 3D models can be produced. A large specimen preserved uncompressed has been documented using a medical X-ray computer tomography scanner. All these methods facilitate the high-resolution documentation of complete specimens (= \"virtual specimens\"). Specimens from both Solnhofen-type lithographic limestones and Lebanon have further been examined for their elemental composition using energy dispersive X-ray spectroscopy (EDX). The fossils differ significantly from the surrounding matrix by containing 6-14% phosphorus.", "keyphrases": ["lithographic limestone", "southern germany", "lebanon"]}
{"id": "10.1017/S1755691016000256", "title": "Hind limb morphometry of terror birds (Aves, Cariamiformes, Phorusrhacidae): functional implications for substrate preferences and locomotor lifestyle", "abstract": "ABSTRACT The hind limbs of birds have long been considered a key feature in the conquest of different environments. However, the high level of morphological diversity encountered complicates the foundation of a good theoretical correlation between morphology, locomotor habits and substrate preference and this, in turn, complicates palaeobiological interpretations. Phorusrhacids (Aves, Cariamiformes) are a good example, since they have been unequivocally categorised as terrestrial birds due to their reduced forelimbs; and as apex predators with the ability to pursue prey based only on their hind limb morphology. Multivariate techniques (PCA and discriminant analysis), based on traditional metrics and geomorphometrics of the hind limb and pelvis, were applied in order to explore terrestriality and cursoriality in phorusrhacids. Although several groups of birds could be identified, when looking solely at hind limb metrics, some phorusrhacids appear to be associated with walking birds, while others are associated with cursorial birds. However, the pelvis separates cursorial birds and phorusrhacids from walking and wading birds. This scenario is complicated further by a lack of clear definition of the different locomotor modes and substrate preferences in extant birds, and this makes it difficult to confirm phorusrhacid cursoriality based solely on morphometrics. However, some qualitative features of the pelvis and foot make the picture a little clearer. To study limb adaptations in fossil birds, a more holistic study, with an emphasis on qualitative features of the whole posterior locomotor module, is necessary, since morphometrics leaves some issues unresolved. A comparison with the wings is also needed, in order to make a more complete analysis of locomotor behaviour.", "keyphrases": ["cariamiformes", "phorusrhacidae", "substrate preference", "cursorial bird", "hind limb"]}
{"id": "paleo.011102", "title": "Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage", "abstract": "Early dinosaurs showed rapid evolutionary rates, which were sustained on the line leading to birds. Maintenance of evolvability in key lineages might explain the uneven distribution of trait diversity among groups of animal species.", "keyphrases": ["body size", "sauropodomorpha", "macroevolutionary study", "numerous study", "oviraptorosaur"]}
{"id": "10.2307/3515465", "title": "Mammal track assemblages from the early Tertiary of China, Peru, Europe and North America", "abstract": "Recent discovery of small, tridactyl vertebrate tracks in a remote region of northwestern China has expanded the data set for the interpretation of similar trackways elsewhere in the world. Previously, similar tracks reported found in Peru from the Formation des Couches Rouges, were attributed to ornithopod dinosaurs, and then used to reinterpret the age of the section as Late Cretaceous. Similarly, the Chinese trackways were, prior to this study, assigned to the very broad chronological interval Cretaceous through Oligocene. Comparison with the similar ichnofaunas in North America and Europe where the age of the tracks is well constrained to Paleogene, and where the tracks are attributed to odd-toed ungulates (perissodactyls), necessitates careful analysis of the affinity and age of the Chinese and Peruvian trackways. In all regions the track assemblages are mammalian (i.e., of ungulate affinity). The Northern hemisphere tracks maybe be attributed to perissodactyls, but the South American tracks probably represent native ungulate groups such as the Notungulata and Litopterna, that show convergent foot morphology. Even at the high taxonomic level of odd toed ungulate such broad biostratigraphic (palichno-stratigraphic) correlations are useful in providing insights into the geologic and tectonic history of terrestrial successions, where the age and faunas are poorly known.", "keyphrases": ["track", "china", "north america"]}
{"id": "paleo.002768", "title": "Mesozoic and Palaeocene lissamphibian assemblages of North America: a comprehensive review", "abstract": "The Mesozoic and Palaeocene record of lissamphibians (i.e. anurans, caudates, gymnophionans and albanerpetontids) in North America is reviewed on the basis of over 400 published and unpublished occurrences from 61 geological formations. The record is heavily biased towards isolated bones, although some associated and articulated skeletons and rare tracks and trackways are known. Most of the localities are in the Western Interior: in central and southern Alberta and southern Saskatchewan, Canada, extending southwards through the USA and into northern Mexico. Outside of that region, records are limited to one Late Cretaceous age formation in Baja California and several Late Triassic and Cretaceous age formations in the eastern USA. Putative lissamphibians have been reported from the Late Triassic (middle Carnian and early Norian). Unambiguous lissamphibians are known from the Early Jurassic (Sinemurian-Pliensbachian), the Late Jurassic (Kimmeridgian-earliest Tithonian), the basal Cretaceous (late Berriasian-Valanginian) and a nearly continuous sequence extending from the Aptian through to the terminal Palaeocene. The Early Jurassic (Sinemurian-Pliensbachian) of Arizona documents the oldest global occurrences of an anuran (i.e. crown frog) and a stem caecilian; the latter also is the only North American fossil occurrence for Gymnophiona prior to the Quaternary. Late Jurassic (Kimmeridgian-earliest Tithonian) age deposits in Colorado, Utah and Wyoming contain a moderate diversity of anurans, urodeles (i.e. crown salamanders) and possibly stem salamanders. A basal Cretaceous locality (late Berriasian-Valanginian) in South Dakota contains a urodele and the first North American occurrence for Albanerpetontidae. Aptian/Albian age localities in Montana, Wyoming, Texas and Oklahoma contain a mixture of anurans, urodeles and albanerpetontidsthat tripartite lissamphibian composition persists in North America through the remainder of the Cretaceous and intermittently through the Palaeocene. Most of the anurans are of uncertain familial affinities. The urodeles contain a mixture of extinct families (Scapherpetontidae and Batrachosauroididae) that were prominent through the Cretaceous into the early Palaeogene, along with the earliest appearances of several extant families, specifically sirenids in the Santonian, amphiumids and proteids in the late Maastrichtian and dicamptodontids and unequivocal cryptobranchids in the late Palaeocene. The albanerpetontid genus Albanerpeton was moderately diverse during the Cretaceous and Palaeocene, before vanishing from the North American record near the end of the Palaeocene. Temporal richness estimates of North American lissamphibians were calculated based on taxic and minimum lineage level occurrence data per 5 million year time interval beginning in the Early Jurassic and though to the end of the Palaeocene. The resulting richness curves demonstrate a general pattern of increasing richness leading up to the Cretaceous-Palaeogene (K-Pg) boundary, with peak values during the Campanian and Maastrichtian and a decline thereafter. The latter part of that pattern suggests higher extinction rates for lissamphibians across the K-Pg boundary compared to previous estimates, This article is a contribution to the special issue \"Mesozoic and Cenozoic lissamphibian and squamate assemblages of Laurasia\" Electronic supplementary material The online version of this article", "keyphrases": ["palaeocene", "north america", "upper shale member", "few fragmentary specimen"]}
{"id": "paleo.002820", "title": "Dinosaur diversification linked with the Carnian Pluvial Episode", "abstract": "Dinosaurs diversified in two steps during the Triassic. They originated about 245 Ma, during the recovery from the Permian-Triassic mass extinction, and then remained insignificant until they exploded in diversity and ecological importance during the Late Triassic. Hitherto, this Late Triassic explosion was poorly constrained and poorly dated. Here we provide evidence that it followed the Carnian Pluvial Episode (CPE), dated to 234\u2013232 Ma, a time when climates switched from arid to humid and back to arid again. Our evidence comes from a combined analysis of skeletal evidence and footprint occurrences, and especially from the exquisitely dated ichnofaunas of the Italian Dolomites. These provide evidence of tetrapod faunal compositions through the Carnian and Norian, and show that dinosaur footprints appear exactly at the time of the CPE. We argue then that dinosaurs diversified explosively in the mid Carnian, at a time of major climate and floral change and the extinction of key herbivores, which the dinosaurs opportunistically replaced.", "keyphrases": ["carnian pluvial episode", "arid", "herbivore"]}
{"id": "10.1098/rsos.161086", "title": "A new ankylosaurine dinosaur from the Judith River Formation of Montana, USA, based on an exceptional skeleton with soft tissue preservation", "abstract": "The terrestrial Judith River Formation of northern Montana was deposited over an approximately 4 Myr interval during the Campanian (Late Cretaceous). Despite having been prospected and collected continuously by palaeontologists for over a century, few relatively complete dinosaur skeletons have been recovered from this unit to date. Here we describe a new genus and species of ankylosaurine dinosaur, Zuul crurivastator, from the Coal Ridge Member of the Judith River Formation, based on an exceptionally complete and well-preserved skeleton (ROM 75860). This is the first ankylosaurin skeleton known with a complete skull and tail club, and it is the most complete ankylosaurid ever found in North America. The presence of abundant soft tissue preservation across the skeleton, including in situ osteoderms, skin impressions and dark films that probably represent preserved keratin, make this exceptional skeleton an important reference for understanding the evolution of dermal and epidermal structures in this clade. Phylogenetic analysis recovers Zuul as an ankylosaurin ankylosaurid within a clade of Dyoplosaurus and Scolosaurus, with Euoplocephalus being more distantly related within Ankylosaurini. The occurrence of Z. crurivastator from the upper Judith River Formation fills a gap in the ankylosaurine stratigraphic and geographical record in North America, and further highlights that Campanian ankylosaurines were undergoing rapid evolution and stratigraphic succession of taxa as observed for Laramidian ceratopsids, hadrosaurids, pachycephalosaurids and tyrannosaurids.", "keyphrases": ["ankylosaurine dinosaur", "judith river formation", "exceptional skeleton", "ankylosaurid tail club"]}
{"id": "10.1029/2002PA000793", "title": "A comparison between excess barium and barite as indicators of carbon export", "abstract": "[1] Since Dymond et al. [1992] proposed the paleoproductivity algorithm based on \u2018\u2018Bio-Ba,\u2019\u2019 which relies on a strong correlation between Ba and organic carbon fluxes in sediment traps, this proxy has been applied in many paleoproductivity studies. Barite, the main carrier of particulate barium in the water column and the phase associated with carbon export, has also been suggested as a reliable paleoproductivity proxy in some locations. We demonstrate that Baexcess (total barium minus the fraction associated with terrigenous material) frequently overestimates Babarite (barium associated with the mineral barite), most likely due to the inclusion of barium from phases other than barite and terrigenous silicates (e.g., carbonate, organic matter, opal, Fe-Mn oxides, and hydroxides). A comparison between overlying oceanic carbon export and carbon export derived from Baexcess shows that the Dymond et al. [1992] algorithm frequently underestimates carbon export but is still a useful carbon export indicator if all caveats are considered before the algorithm is applied. Babarite accumulation rates from a wide range of core top sediments from different oceanic settings are highly correlated to surface ocean 14 C and Chlorophyll a measurements of primary production. This relationship varies by ocean basin, but with the application of the appropriate f ratio to 14 C and Chlorophyll a primary production estimates, the plot of Babarite accumulation and carbon export for the equatorial Pacific, Atlantic, and Southern Ocean converges to a global relationship that can be used to reconstruct paleo carbon export. INDEX TERMS: 3022 Marine Geology and Geophysics: Marine sediments\u2014processes and transport; 4267 Oceanography: General: Paleoceanography; 4825 Oceanography: Biological and Chemical: Geochemistry; KEYWORDS: paleoproductivity, barite, export production, excess barium, marine sediments Citation: Eagle, M., A. Paytan, K. R. Arrigo, G. van Dijken, and R. W. Murray, A comparison between excess barium and barite as indicators of carbon export, Paleoceanography, 18(1), 1021, doi:10.1029/2002PA000793, 2003.", "keyphrases": ["excess barium", "carbon export", "strong correlation", "accumulation"]}
{"id": "10.1080/14772019.2010.484650", "title": "A new early dinosaur (Saurischia: Sauropodomorpha) from the Late Triassic of Argentina: a reassessment of dinosaur origin and phylogeny", "abstract": "It was traditionally thought that the oldest known dinosaur assemblages were not diverse, and that their early diversification and numerical dominance over other tetrapods occurred during the latest Triassic. However, new evidence gathered from the lower levels of the Ischigualasto Fm. of Argentina challenges this view. New dinosaur remains are described from this stratigraphical unit, including the new species Chromogisaurus novasi. This taxon is distinguished from other basal dinosauriforms by the presence of proximal caudals without median notch separating the postzygapophyses, femoral lateral surface with deep and large fossa immediately below the trochanteric shelf, and metatarsal II with strongly dorsoventrally asymmetric distal condyles. A phylogenetic analysis found Chromogisaurus to lie at the base of Sauropodomorpha, as a member of Guaibasauridae, an early branch of basal sauropodomorphs composed of Guaibasaurus, Agnosphitys, Panphagia, Saturnalia and Chromogisaurus. Such an affinity is for the first time suggested for Guaibasaurus, whereas Panphagia is not recovered as the most basal sauropodomorph. Furthermore, Chromogisaurus is consistently located as more closely related to Saturnalia than to any other dinosaur. Thus, the Saturnalia + Chromogisaurus clade is named here as the new subfamily Saturnaliinae. In addition, Eoraptor is found to be the sister-taxon of Neotheropoda, and herrerasaurids to be non-eusaurischian saurischians. The new evidence presented here demonstrates that dinosaurs first appeared in the fossil record as a diverse group, although they were a numerically minor component of faunas in which they occur. Accordingly, the early increase of dinosaur diversity and their numerical dominance over other terrestrial tetrapods were diachronous processes, with the latter preceded by a period of low abundance but high diversity.", "keyphrases": ["sauropodomorpha", "argentina", "phylogenetic analysis"]}
{"id": "10.5027/andgeov41n1-a02", "title": "Onset of the Middle Eocene global cooling and expansion of open-vegetation habitats in central Patagonia", "abstract": "Climate-driven changes in terrestrial environments and biomes after the Early Eocene Climatic Optimum are poorly documented from southern continents. Particularly, Middle Eocene-Early Oligocene leaf and pollen data from Central Patagonia (46oS, Argentina) are not sufficient to characterize floristic paleocommunities. Paleosols of the Canadon Vaca (~45-42 Ma) and Gran Barranca (42-38.5 Ma) members (Sarmiento Formation), studied at Canadon Vaca, solve such deficiency and help to reconstruct Middle Eocene landscapes in the beginning of the Cenozoic cooling-drying trend. Vitric Entisols, mollic Andisols and andic Alfisols, showing granular structure and diverse micropeds, are cyclically arranged mainly in response to variation in fine volcaniclastic eolian supply, which in turn governed ecosystem stability and maturity. Soils formed in loessic plains crossed by minor ephemeral rivers, supported open herbaceous-arboreal communities which grew in seasonal, subhumid and warmtemperate conditions. Phytoliths produced by Arecaceae, megathermic graminoids, sedges and dicots, from the upper part of the studied unit, represent subtropical savannas with grasses and variable number of palms and other trees. Considering the abundant paleobotanical and paleopedological antecedents of Late Paleocene-Early Eocene warm and humid forested environments in the same region, the lower Sarmiento Formation records the initial expansion of open herbaceous communities and the appearance of grassy habitats during the greenhouse to icehouse transition in the Middle Eocene.", "keyphrases": ["middle eocene", "patagonia", "paleosol"]}
{"id": "paleo.009853", "title": "Eccentricity and obliquity paced carbon cycling in the Early Triassic and implications for post-extinction ecosystem recovery", "abstract": "The timing of marine ecosystem recovery following the End Permian Mass Extinction (EPME) remains poorly constrained given the lack of radiometric ages. Here we develop a high-resolution carbonate carbon isotope (\u03b413Ccarb) record for 3.20 million years of the Olenekian in South China that defines the astronomical time-scale for the critical interval of major evolutionary and oceanic events in the Spathian. \u03b413Ccarb documents eccentricity modulation of carbon cycling through the period and a strong obliquity signal. A shift in phasing between short and long eccentricity modulation, and amplification of obliquity, is nearly coincident with a 2% decrease in seawater \u03b413CDIC, the last of a longer-term stepped decrease through the Spathian. The mid-Spathian shift in seawater \u03b413CDIC to typical thermocline values is interpreted to record a major oceanic reorganization with global climate amelioration. Coincidence of the phasing shift with the first occurrence of marine reptiles (248.81 Ma), suggests that their invasion into the sea and the onset of a complex ecosystem were facilitated by restoration of deep ocean ventilation linked mechanistically to a change in the response of the oceanic carbon reservoir to astronomical forcing. Together these records place the first constraints on the duration of the post-extinction recovery to 3.35 myr.", "keyphrases": ["obliquity", "carbon cycling", "ecosystem recovery", "marine reptile", "myr"]}
{"id": "paleo.010460", "title": "No Reliable Evidence for a Neanderthal-Ch\u00e2telperronian Association at La Roche-\u00e0-Pierrot, Saint-C\u00e9saire", "abstract": "The demise of Neanderthals and their interaction with dispersing anatomically modern human populations remain some of the most contentious issues in palaeoanthropology. The Ch\u00e2telperronian, now generally recognized as the first genuine Upper Palaeolithic industry in Western Europe and commonly attributed to the Neanderthals, plays a pivotal role in these debates. The Neanderthal authorship of this techno-complex is based on reported associations of Neanderthal skeletal material with Ch\u00e2telperronian assemblages at only two sites, La Roche-\u00e0-Pierrot (Saint-C\u00e9saire) and the Grotte du Renne (Arcy-sur-Cure). The reliability of such an association has, however, been the subject of heated controversy. Here we present a detailed taphonomic, spatial and typo-technological reassessment of the level (EJOP sup) containing the Neanderthal skeletal material at Saint-C\u00e9saire. Our assessment of a new larger sample of lithic artifacts, combined with a systematic refitting program and spatial projections of diagnostic artifacts, produced no reliable evidence for a Neanderthal-Ch\u00e2telperronian association at the site. These results significantly impact current models concerning the Middle-to-Upper Palaeolithic transition in Western Europe and force a critical reappraisal of who exactly were the makers of the Ch\u00e2telperronian.", "keyphrases": ["reliable evidence", "neanderthal-ch\u00e2telperronian association", "saint-c\u00e9saire", "debate", "researcher"]}
{"id": "10.1029/2009GC002788", "title": "Geochemistry of oceanic anoxic events", "abstract": "Oceanic anoxic events (OAEs) record profound changes in the climatic and paleoceanographic state of the planet and represent major disturbances in the global carbon cycle. OAEs that manifestly caused major chemical change in the Mesozoic Ocean include those of the early Toarcian (Posidonienschiefer event, T\u2010OAE, \u223c183 Ma), early Aptian (Selli event, OAE 1a, \u223c120 Ma), early Albian (Paquier event, OAE 1b, \u223c111 Ma), and Cenomanian\u2013Turonian (Bonarelli event, C/T OAE, OAE 2, \u223c93 Ma). Currently available data suggest that the major forcing function behind OAEs was an abrupt rise in temperature, induced by rapid influx of CO2 into the atmosphere from volcanogenic and/or methanogenic sources. Global warming was accompanied by an accelerated hydrological cycle, increased continental weathering, enhanced nutrient discharge to oceans and lakes, intensified upwelling, and an increase in organic productivity. An increase in continental weathering is typically recorded by transient increases in the seawater values of 87Sr/86Sr and 187Os/188Os ratios acting against, in the case of the Cenomanian\u2010Turonian and early Aptian OAEs, a longer\u2010term trend to less radiogenic values. This latter trend indicates that hydrothermally and volcanically sourced nutrients may also have stimulated local increases in organic productivity. Increased flux of organic matter favored intense oxygen demand in the water column, as well as increased rates of marine and lacustrine carbon burial. Particularly in those restricted oceans and seaways where density stratification was favored by paleogeography and significant fluvial input, conditions could readily evolve from poorly oxygenated to anoxic and ultimately euxinic (i.e., sulfidic), this latter state being geochemically the most significant. The progressive evolution in redox conditions through phases of denitrification/anammox, through to sulfate reduction accompanied by water column precipitation of pyrite framboids, resulted in fractionation of many isotope systems (e.g., N, S, Fe, Mo, and U) and mobilization and incorporation of certain trace elements into carbonates (Mn), sulfides, and organic matter. Sequestration of CO2 in organic\u2010rich black shales and by reaction with silicate rocks exposed on continents would ultimately restore climatic equilibrium but at the expense of massive chemical change in the oceans and over time scales of tens to hundreds of thousands of years.", "keyphrases": ["oceanic anoxic event", "sequestration", "black shale"]}
{"id": "paleo.002090", "title": "Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics", "abstract": "Bite mechanics and feeding behaviour in Tyrannosaurus rex are controversial. Some contend that a modest bite mechanically limited T. rex to scavenging, while others argue that high bite forces facilitated a predatory mode of life. We use dynamic musculoskeletal models to simulate maximal biting in T. rex. Models predict that adult T. rex generated sustained bite forces of 35 000\u201357 000 N at a single posterior tooth, by far the highest bite forces estimated for any terrestrial animal. Scaling analyses suggest that adult T. rex had a strong bite for its body size, and that bite performance increased allometrically during ontogeny. Positive allometry in bite performance during growth may have facilitated an ontogenetic change in feeding behaviour in T. rex, associated with an expansion of prey range in adults to include the largest contemporaneous animals.", "keyphrases": ["bite performance", "tyrannosaurus rex", "bite force"]}
{"id": "paleo.000732", "title": "Micro\u2010computed tomography reveals a diversity of Peramuran mammals from the Purbeck Group (Berriasian) of England", "abstract": "Abstract: The known sample of the important pretribosphenic mammal Peramus tenuirostris, housed in the Natural History Museum (London, UK), was imaged using micro\u2010computed tomography (CT). Substantial morphological diversity was discovered, prompting establishment (and resurrection) of additional taxa from within the existing hypodigm of Peramus tenuirostris: Peramus dubius comb. nov., Kouriogenys minor gen. nov. and Peramuroides tenuiscus gen. et sp. nov. The Peramura are revised; this group is restricted to taxa with clear evidence of a fully functional upper molar embrasure for the dominant lower molar talonid cusp (hypoconid), either through development of wear facet 4 or through differentiation of a distinct hypoconulid. The Peramura are the most likely sister taxon to the Tribosphenida (including living marsupials and placentals) and represent a distinct molar morphotype, transitional between primitive lineages characterized by dominant orthal shear (e.g. dryolestoids) and those with modern, multi\u2010functional tribospheny. A very large masseteric foramen is identified in peramurans, but this feature appears to be autapomorphic and of uncertain function.", "keyphrases": ["tomography", "tribosphenida", "masseteric foraman"]}
{"id": "10.1093/icb/43.1.178", "title": "The Ordovician Radiation: A Follow-up to the Cambrian Explosion?1", "abstract": "Abstract There was a major diversification known as the Ordovician Radiation, in the period immediately following the Cambrian. This event is unique in taxonomic, ecologic and biogeographic aspects. While all of the phyla but one were established during the Cambrian explosion, taxonomic increases during the Ordovician were manifest at lower taxonomic levels although ordinal level diversity doubled. Marine family diversity tripled and within clade diversity increases occurred at the genus and species levels. The Ordovician radiation established the Paleozoic Evolutionary Fauna; those taxa which dominated the marine realm for the next 250 million years. Community structure dramatically increased in complexity. New communities were established and there were fundamental shifts in dominance and abundance. Over the past ten years, there has been an effort to examine this radiation at different scales. In comparison with the Cambrian explosion which appears to be more globally mediated, local and regional studies of Ordovician faunas reveal sharp transitions with timing and magnitudes that vary geographically. These transitions suggest a more episodic and complex history than that revealed through synoptic global studies alone. Despite its apparent uniqueness, we cannot exclude the possibility that the Ordovician radiation was an extension of Cambrian diversity dynamics. That is, the Ordovician radiation may have been an event independent of the Cambrian radiation and thus requiring a different set of explanations, or it may have been the inevitable follow-up to the Cambrian radiation. Future studies should focus on resolving this issue.", "keyphrases": ["ordovician radiation", "follow-up", "diversification", "cambrian explosion"]}
{"id": "10.3201/eid1406.070707", "title": "Chagas disease in ancient hunter-gatherer population, Brazil.", "abstract": "To the Editor: Chagas disease, caused by the protozoan Trypanosoma cruzi, and first described by Carlos Chagas in 1909, is endemic to Latin America. As a results of multinational control initiatives launched in the 1990s, the disease prevalence has been reduced. This campaign was focused on the interruption of T. cruzi vectorial transmission by eliminating domiciled triatomines. In 2006, Brazil was declared to be free from T. cruzi transmission by Triatoma infestans (1). T. cruzi is a heterogeneous taxon with multiple mammal hosts and vectors, besides alternative routes of infection and infective forms. In the Brazilian Amazon region, where domiciled triatomines have not been reported, human cases of Chagas disease have been increasing (2). This increase has been attributed to uncontrolled migration and deforestation (2). Additionally, recent outbreaks of Chagas disease attributed to oral transmission in previously non\u2013disease-endemic areas out of the Amazon region (3) indicate that a new epidemiologic profile is emerging in Brazil. \n \nT. cruzi has 2 main genotypes, T. cruzi I and T. cruzi II, and these subpopulations display distinct biologic, biochemical, and genetic profiles. In Brazil, T. cruzi I is widespread among wild mammals and sylvatic vectors of all biomes. Moreover, this genotype is commonly isolated from humans and wild mammals in the Amazon Basin. In contrast, T. cruzi II, has a focal distribution in nature but is the main agent of human infection in other Brazilian regions (4). \n \nIn this report, we describe the finding of T. cruzi in human remains dating back 4,500\u20137,000 years that were obtained from a Brazilian archeological site and, the recovery of an ancient DNA (aDNA) sequence corresponding to the parasite lineage type I. The mummy, called AM1, was a woman \u224835 years of age from a hunter-gatherer population. She was found in Abrigo do Malhador archeological site, Peruacu Valley, Minas Gerais State (5). This region, where the semiarid ecosystem is predominant, has a dry climate, karst relief (an area of limestone terrain characterized by sinks, ravines, and underground streams), and soil with a basic pH. These conditions have contributed to the preservation of specimens. \n \nThe remains were excavated in 1985 and maintained in an environment protected from light and humidity. In 2005, after taking precautions to avoid contamination with exogenous DNA or cross-contamination between samples, we collected \u22486 cm of a rib fragment from AM1. All experiments were conducted in a restricted area that was isolated from the major laboratory, where post-PCR experiments were performed. T. cruzi had never been used in either laboratory. Mitochondrial DNA haplotypes of laboratory staff were determined to control contamination. PCR-positive controls (T. cruzi) were not used. The rib surface was gently scraped to remove impurities and decontaminated with bleach (6% NaOCl) and UV light (15 min for each side). We processed 300 mg of bone powder according to the extraction protocol of dehybernation B solution of the Geneclean Kit for Ancient DNA (Bio101, La Jolla, CA, USA). By using specific set of primers (6), a 350-bp miniexon gene fragment was successfully recovered by PCR (Figure); the fragment corresponded to the T. cruzi I lineage, according to miniexon gene typing assay (6). Moreover, nucleotide sequence analysis (341 bp) (GenBank accession no. {\"type\":\"entrez-nucleotide\",\"attrs\":{\"text\":\"EF626693\",\"term_id\":\"157003901\"}}EF626693), showed 98% similarity with T. cruzi I sequences in GenBank. Additionally, total aDNA hybridization with T. cruzi probes (miniexon and total kinetoplast DNA) confirmed the infection. Sequence analysis of the human mitochondrial DNA HVS-I region characterized this person as belonging to haplogroup B (GenBank accession no. {\"type\":\"entrez-nucleotide\",\"attrs\":{\"text\":\"EU359272\",\"term_id\":\"164597965\"}}EU359272), one of the founder human haplogroups in the Americas. \n \n \n \nFigure \n \nTrypanosoma cruzi miniexon gene typing assay. Lanes 1 and 2, T. cruzi II (300 bp) and T. cruzi I (350 bp) markers, respectively; lane 3, T. cruzi I cloned fragment recovered from Brazilian mummy; lane 4, 100-bp ladder. \n \n \n \nThe antiquity of human T. cruzi infection in South America has been demonstrated on the basis of paleonthologic studies. Clinical manifestations of Chagas disease were observed in Chilean mummies from pre-Columbian times (7). Moreover, a T. cruzi kinetoplast DNA region was recovered in Chilean and Peruvian mummies from up to 9,000 years ago (8,9). \n \nIn Brazil, the current epidemiologic scenario concerning Chagas disease in indigenous populations involves ecologic aspects of their settlements, along with nomad habits, which prevent triatomine nesting and, therefore, the infection. The beginning of T. cruzi transmission to humans is attributed to the domiciliation of T. infestans as a consequence of precarious mud dwellings, built after European colonization (10). In this report, we showed that T. cruzi human infection in Brazil is ancient, dating back at least 4,500 years, and therefore occurring in hunter-gatherer populations largely preceding T. infestans domiciliation. The presence of the T. cruzi I genotype infecting humans 4,500\u20137,000 years ago in Minas Gerais State, where this genotype is currently absent (6), suggests that the distribution pattern of T. cruzi genotypes in humans has changed in time and place. Moreover, the recovery of an aDNA sequence and the possibility of genotyping parasites from human remains make it possible to reconstruct the early dispersion patterns of T. cruzi subpopulations. On the basis of our results, one may speculate that the current outbreaks of human T. cruzi infection, independent of triatomine domiciliation, are the reemergence of the ancient epidemiologic scenario of Chagas disease in Brazil.", "keyphrases": ["hunter-gatherer population", "parasite", "chagas disease"]}
{"id": "10.1098/rspb.2016.0593", "title": "Peptide sequences from the first Castoroides ohioensis skull and the utility of old museum collections for palaeoproteomics", "abstract": "Vertebrate fossils have been collected for hundreds of years and are stored in museum collections around the world. These remains provide a readily available resource to search for preserved proteins; however, the vast majority of palaeoproteomic studies have focused on relatively recently collected bones with a well-known handling history. Here, we characterize proteins from the nasal turbinates of the first Castoroides ohioensis skull ever discovered. Collected in 1845, this is the oldest museum-curated specimen characterized using palaeoproteomic tools. Our mass spectrometry analysis detected many collagen I peptides, a peptide from haemoglobin beta, and in vivo and diagenetic post-translational modifications. Additionally, the identified collagen I sequences provide enough resolution to place C. ohioensis within Rodentia. This study illustrates the utility of archived museum specimens for both the recovery of preserved proteins and phylogenetic analyses.", "keyphrases": ["castoroides ohioensis skull", "museum collection", "peptide"]}
{"id": "10.1093/biolinnean/blw044", "title": "First palaeohistological inference of resting metabolic rate in an extinct synapsid, Moghreberia nmachouensis (Therapsida: Anomodontia)", "abstract": "The independent acquisition of endothermy in synapsids and diapsids are major events in vertebrate evolution since they were the driving force of a suite of correlated changes in anatomical, physiological, behavioural and ecological traits. While avian endothermy is assumed to have occurred at the archosauriform node, the acquisition of mammalian endothermy is poorly constrained both temporally and phylogenetically. Among the many unequivocal anatomical correlates of endothermy in synapsids, the presence of insulative pelage or respiratory turbinates only allows discrete inferences of presence/absence of endothermy. The analysis of bone histology allows richer palaeobiological inferences. We described the osteohistology and growth patterns of Moghreberia nmachouensis and two related taxa (Lystrosaurus and Oudenodon) for comparative purposes. Our observations suggest increasing growth rates from Moghreberia [the presence of incipient fibrolamellar bone (FLB) in humerus and femur], to Lystrosaurus (the presence of well-developed FLB in the femur but the presence of incipient FLB in the humerus), to Oudenodon (the presence of well-developed FLB in humerus and femur). However, qualitative histology does not allow reliable inferences about the occurrence of endothermy. We performed the first quantitative inferences of resting metabolic rates on fossil synapsids (M. nmachouensis as a model and Lystrosaurus and Oudenodon for comparative purposes) using quantitative histology (size, shape and density of osteocyte lacunae) combined with phylogenetic eigenvector maps. Our inferences are consistent with our qualitative histological observations: the mass-independent resting metabolic rate inferred for M. nmachouensis (2.58 mLO2 h\u22121 g\u22120.67) is lower than the value inferred for Lystrosaurus (3.80 mLO2 h\u22121 g\u22120.67), which is lower than that inferred for Oudenodon (4.58 mLO2 h\u22121 g\u22120.67). Optimization of these inferences onto a phylogenetic tree of tetrapods using the parsimony method allowed us to better constrain the temporal (more than 260 Myr ago) and phylogenetic (Neotherapsida) frames of the acquisition of mammalian endothermy.", "keyphrases": ["metabolic rate", "synapsid", "moghreberia nmachouensis", "oudenodon"]}
{"id": "paleo.012559", "title": "Ancient DNA Analysis of the Oldest Canid Species from the Siberian Arctic and Genetic Contribution to the Domestic Dog", "abstract": "Modern Arctic Siberia provides a wealth of resources for archaeological, geological, and paleontological research to investigate the population dynamics of faunal communities from the Pleistocene, particularly as the faunal material coming from permafrost has proven suitable for genetic studies. In order to examine the history of the Canid species in the Siberian Arctic, we carried out genetic analysis of fourteen canid remains from various sites, including the well-documented Upper Paleolithic Yana RHS and Early Holocene Zhokhov Island sites. Estimated age of samples range from as recent as 1,700 years before present (YBP) to at least 360,000 YBP for the remains of the extinct wolf, Canis cf. variabilis. In order to examine the genetic affinities of ancient Siberian canids species to the domestic dog and modern wolves, we obtained mitochondrial DNA control region sequences and compared them to published ancient and modern canid sequences. The older canid specimens illustrate affinities with pre-domestic dog/wolf lineages while others appear in the major phylogenetic clades of domestic dogs. Our results suggest a European origin of domestic dog may not be conclusive and illustrates an emerging complexity of genetic contribution of regional wolf breeds to the modern Canis gene pool.", "keyphrases": ["siberian arctic", "genetic contribution", "domestic dog", "pleistocene"]}
{"id": "10.1017/S1477201904001518", "title": "Phylogeny of the carnivora: Basal relationships among the carnivoramorphans, and assessment of the position of \u2018miacoidea\u2019 relative to carnivora", "abstract": "Synopsis The relationships between the earliest members of the Carnivoramorpha and the crown\u2010clade Carnivora are more firmly resolved. The data set for the phylogenetic analyses includes 99 cranial and dental characters from 40 taxa, representing a wide range of early Cenozoic fossil carni\u2010voramorphan taxa traditionally included within the \u2018Miacoidea\u2019, representatives of extant Carnivora and outgroups. New fossils of Tapocyon and O\u00f6dectes, and more thorough anatomical analyses, significantly increase the taxon and character sampling available for the earliest members of the Carnivoramorpha. The first auditory region known for O\u00f6dectes is described. We test the monophyly of the Carnivoramorpha and various subclades, as well as interrelationships of \u2018Miacoidea\u2019 taxa relative to each other and to the Carnivora. The monophyly of the Carnivora and Carnivoramorpha is supported, relative to other Ferae (two hyaenodontid \u2018creodonts') and Eutherian outgroups. There is compelling evidence that \u2018Miacidae\u2019 and Viverravidae are not basal members of the Caniformia and Feliformia but rather are excluded from the Carnivora (as phylogenetically defined, Wyss & Flynn 1993, emended by Bryant 1996). A monophyletic Viverravidae is strongly supported, forming the nearest outgroup to all other Carnivoramorpha. \u2018Miacidae\u2019 is not monophyletic; rather it appears to represent a paraphyletic array of stem taxa, basal to the Carnivora. We discuss character evolution and transformations in the light of these new phylogenetic hypotheses. Basicranial characters are not significantly more useful (less homoplasious) than dental features and thus do not represent a \u2018holy grail\u2019 morphological character system for reconstructing carnivoramorphan phylogeny. The results indicate that the split between the Feliformia and Caniformia, now estimated at a minimum age of \u223c43 Ma, appears to have taken place more recently than many earlier studies suggested (see also Flynn 1996).", "keyphrases": ["carnivora", "miacoidea", "relative", "outgroup"]}
{"id": "10.1017/s0094837300006527", "title": "Constructional morphology of sand dollars", "abstract": "This paper analyzes an aberrant group of echinoids in terms of constructional morphology, i.e., as modification of an established \u201cBauplan\u201d by a set of new functional and morphogenetic constraints and possibilities. The characteristics of sand dollars (flat test, spine differentiation, branched food grooves, lunules) are related to a particular combination of burrowing and sieve feeding in sandy sediments. It has independently evolved from less specialized Clypeasteroids in at least three lineages (Scutellina, Rotulidae, Arachnoididae), which have solved inherent problems differently (sutural interlocking; growth patterning of food grooves and canal systems; lunule formation; weight belts). These three groups have radiated in different degrees due to their different palegeographic histories.", "keyphrases": ["sand dollar", "echinoid", "constructional morphology"]}
{"id": "10.1126/science.aaa0114", "title": "Genomic structure in Europeans dating back at least 36,200 years", "abstract": "The origin of contemporary Europeans remains contentious. We obtained a genome sequence from Kostenki 14 in European Russia dating from 38,700 to 36,200 years ago, one of the oldest fossils of anatomically modern humans from Europe. We find that Kostenki 14 shares a close ancestry with the 24,000-year-old Mal\u2019ta boy from central Siberia, European Mesolithic hunter-gatherers, some contemporary western Siberians, and many Europeans, but not eastern Asians. Additionally, the Kostenki 14 genome shows evidence of shared ancestry with a population basal to all Eurasians that also relates to later European Neolithic farmers. We find that Kostenki 14 contains more Neandertal DNA that is contained in longer tracts than present Europeans. Our findings reveal the timing of divergence of western Eurasians and East Asians to be more than 36,200 years ago and that European genomic structure today dates back to the Upper Paleolithic and derives from a metapopulation that at times stretched from Europe to central Asia. An ancient human genome illuminates human demography in Eurasia and Europe. Secrets of human ancestor evolution revealed Studies of ancient humans help us understand the movement and evolution of modern populations of humans. Seguin-Orlando et al. present the genome of an ancient individual, K14, from northern Russia who lived over 36,000 years ago. K14 is more similar to west Eurasians and Europeans than to east Asians, indicating that these populations had already diverged. Science, this issue p. 1113", "keyphrases": ["europeans", "dna", "human genome"]}
{"id": "paleo.003986", "title": "The oldest dairoidid crab (Decapoda, Brachyura, Parthenopoidea) from the Eocene of Spain", "abstract": "Eubrachyurans, or \u2018higher\u2019 true crabs, are the most speciose group of decapod crustaceans and have a rich fossil record extending into the Early Cretaceous. However, most extant families are first found in the fossil record in the Palaeogene, and particularly in the Eocene. Unfortunately, fossils of many early eubrachyuran groups are often fragmentary, and only a few studies have combined extinct and extant taxa in a phylogenetic context using different optimality criteria. Here, we report the dairoidid crab Phrynolambrus sagittalis sp. nov., an enigmatic eubrachyuran from the upper Eocene of Huesca (northern Spain), whose completeness and exquisite preservation permit examination of its anatomy in a phylogenetic context. Dairoidids have previously been considered among the oldest stone crabs (Eriphioidea) or elbow crabs (Parthenopoidea), two disparate and distantly related groups of true crabs living today. Mechanical preparation and computed tomography of the fossil material revealed several diagnostic features that allow a detailed comparison with families across the crab tree of life, and test hypotheses about its phylogenetic affinities. Phrynolambrus sagittalis is the first record of the genus in the Iberian Peninsula, and represents one of the oldest crown parthenopoidean crabs worldwide, expanding our knowledge of the biogeographical distribution of elbow crabs during the Palaeogene, as well as their early origins, anatomical diversity and systematic affinities. Understanding the disparity of Eocene eubrachyurans is pivotal to disentangling the systematic relationships among crown families, and interpreting the spatio\u2010temporal patterns leading to the evolution of modern faunas.", "keyphrases": ["crab", "parthenopoidea", "eocene", "decapod crustacean"]}
{"id": "paleo.000619", "title": "The first fossil parrot (Aves, Psittaciformes) from Siberia and its implications for the historical biogeography of Psittaciformes", "abstract": "Modern parrots (crown Psittaciformes) are a species-rich group of mostly tropical and subtropical birds with a very limited fossil record. A partial tarsometatarsus from the late Early Miocene of Siberia (Baikal Lake) is the first pre-Quaternary find of crown Psittaciformes in Asia (and Siberia in particular) and is also the northern-most find of this bird order worldwide. This find documents a broad geographical distribution of parrots during the warmest phase of the Miocene (the so-called \u2018Miocene Climatic Optimum\u2019), which has implications for the historical biogeography of Psittaciformes. The presence of parrots on both sides of the Pacific Ocean at the end of the Early Miocene implies a (most probably eastwards) trans-Beringian dispersal which likely took place about 16\u201318 Ma. The broad Eurasian distribution of parrots in the past further supports a hypothesis that ancestors of modern genera Coracopsis and Agapornis could reach Africa from Eurasia.", "keyphrases": ["psittaciformes", "siberia", "historical biogeography", "passeriformes", "pandionidae"]}
{"id": "10.1017/S0022336000025312", "title": "Ecdysis in Flexicalymene meeki (Trilobita)", "abstract": "The ecdysial style of Flexicalymene meeki (Foerste) from the Upper Ordovician of the Cincinnati arch (Ohio) is best characterized by a spectrum of configurations. Recurring patterns of displaced tergites and points of disarticulation indicate differential susceptibility of the exoskeleton to disarticulation during ecdysis. Specimens identified as exuviae are characterized by one or more of the following: thoracic segments displaced (unevenly spaced, disarticulated or telescoped); pygidia and/or cephala rotated away from the sagittal line; cephalon sharply bent ventrally at first thoracic segment; librigenae separated or folded ventrally along facial sutures; \u201cextra\u201d tergites (exuvia) superposed on the new exoskeleton; and missing elements, especially librigenae and hypostomae. The range of exuvial configurations suggests a variety of ecdysial behavior in this trilobite.", "keyphrases": ["flexicalymene meeki", "exuviae", "ecdysis"]}
{"id": "10.1126/science.aax0612", "title": "Solar System chaos and the Paleocene\u2013Eocene boundary age constrained by geology and astronomy", "abstract": "Filling a dating hole The periodic nature of Earth's orbit around the Sun produces cycles of insolation reflected in climate records. Conversely, these climate records can be used to infer changes in the dynamics of the Solar System, which is inherently chaotic and not always similarly periodic. A particular obstacle is the lack of well-defined planetary orbital constraints between 50 and 60 million years ago. Zeebe and Lourens found an astronomical solution for that interval showing that the Solar System experienced a specific resonance transition pattern. These data provide a measure of the duration of the Paleocene-Eocene Thermal Maximum. Science, this issue p. 926 Astronomical calculations reveal that a resonant transition in the Solar System occurred between 50 and 60 million years ago. Astronomical calculations reveal the Solar System\u2019s dynamical evolution, including its chaoticity, and represent the backbone of cyclostratigraphy and astrochronology. An absolute, fully calibrated astronomical time scale has hitherto been hampered beyond ~50 million years before the present (Ma) because orbital calculations disagree before that age. Here, we present geologic data and a new astronomical solution (ZB18a) showing exceptional agreement from ~58 to 53 Ma. We provide a new absolute astrochronology up to 58 Ma and a new Paleocene\u2013Eocene boundary age (56.01 \u00b1 0.05 Ma). We show that the Paleocene\u2013Eocene Thermal Maximum (PETM) onset occurred near a 405-thousand-year (kyr) eccentricity maximum, suggesting an orbital trigger. We also provide an independent PETM duration (170 \u00b1 30 kyr) from onset to recovery inflection. Our astronomical solution requires a chaotic resonance transition at ~50 Ma in the Solar System\u2019s fundamental frequencies.", "keyphrases": ["paleocene\u2013eocene boundary age", "petm", "onset"]}
{"id": "paleo.002955", "title": "Palaeohistology and external microanatomy of rauisuchian osteoderms (Archosauria: Pseudosuchia)", "abstract": "Abstract:\u2002 The presence of postcranial dermal armour is plesiomorphic for Archosauria. Here, we survey the external microanatomy and histology of postcranial osteoderms (i.e. dorsal paramedian and caudal osteoderms) of rauisuchians, a widely distributed assemblage of extinct predatory pseudosuchians from the Triassic. The osteoderms of eight rauisuchian taxa were found to be rather compact bones, which usually lack significant bone remodelling or large areas of cancellous bone. The presence of highly vascularized woven or fibrolamellar bone tissue deposited in the core areas indicates higher growth rates during earlier life stages, whereas a more compact parallel\u2010fibred bone matrix indicates reduced growth rates in later development. This pattern of change corroborates earlier studies on long bone histology. With the exception of a bone tissue found in the sample of Batrachotomus kupferzellensis, which might be the result of metaplastic ossification, the general mode of skeletogenesis is comparable with intramembraneous ossification. The lack of cancellous bone tissue and remodelling processes associated with bone ornamentation, as well as the predominantly intramembraneous mode of ossification, indicates that rauisuchian osteoderm formation differs profoundly from that of the osteoderms of the only extant pseudosuchian lineage, the crocodylians.", "keyphrases": ["external microanatomy", "osteoderm", "archosauria"]}
{"id": "10.1111/j.1475-4983.2011.01098.x", "title": "Palaeohistology and external microanatomy of rauisuchian osteoderms (Archosauria: Pseudosuchia)", "abstract": "Abstract:\u2002 The presence of postcranial dermal armour is plesiomorphic for Archosauria. Here, we survey the external microanatomy and histology of postcranial osteoderms (i.e. dorsal paramedian and caudal osteoderms) of rauisuchians, a widely distributed assemblage of extinct predatory pseudosuchians from the Triassic. The osteoderms of eight rauisuchian taxa were found to be rather compact bones, which usually lack significant bone remodelling or large areas of cancellous bone. The presence of highly vascularized woven or fibrolamellar bone tissue deposited in the core areas indicates higher growth rates during earlier life stages, whereas a more compact parallel\u2010fibred bone matrix indicates reduced growth rates in later development. This pattern of change corroborates earlier studies on long bone histology. With the exception of a bone tissue found in the sample of Batrachotomus kupferzellensis, which might be the result of metaplastic ossification, the general mode of skeletogenesis is comparable with intramembraneous ossification. The lack of cancellous bone tissue and remodelling processes associated with bone ornamentation, as well as the predominantly intramembraneous mode of ossification, indicates that rauisuchian osteoderm formation differs profoundly from that of the osteoderms of the only extant pseudosuchian lineage, the crocodylians.", "keyphrases": ["external microanatomy", "osteoderm", "archosauria"]}
{"id": "paleo.002962", "title": "Keratolite\u2013stromatolite consortia mimic domical and branched columnar stromatolites", "abstract": "The term keratolite is proposed for keratosan sponge carbonate dominated by vermiform fabric that preserves the outlines of the original spongin skeleton. Thinly (<~2 cm) interlayered keratosan-microbial carbonate consortia in peritidal sediments near the Cambrian-Ordovician boundary in Newfoundland, Canada, are macroscopically indistinguishable from stromatolites. These carbonate domes and columns consist of approximately equal proportions of keratolite and stromatolite. The keratolite is characterized by pervasive microscopic vermiform fabric, which reflects the original spongin framework. The stromatolite is characterized by fine-grained carbonate with cross-cutting laminae, which primarily formed by sediment trapping. The intimate association of keratolite and stromatolite in these deposits indicates that the sponges and microbes involved shared similar environmental tolerances and requirements. Synchronicity of sponge colonization, followed by stromatolite regrowth, across adjacent columns suggests coordinated responses by both sponges and microbes to local ecophysiological stimuli. Due to their macroscopic similarity, keratolite and fine-grained stromatolite may commonly have been confused with one-another throughout the Phanerozoic, and possibly longer.", "keyphrases": ["stromatolite", "sponge", "keratose", "carbonate microspar", "post-mortem calcification"]}
{"id": "paleo.011426", "title": "A new model for ancient DNA decay based on paleogenomic meta-analysis", "abstract": "The persistence of DNA over archaeological and paleontological timescales in diverse environments has led to revolutionary body of paleogenomic research, yet the dynamics of DNA degradation are still poorly understood. We analyzed 185 paleogenomic datasets and compared DNA survival with environmental variables and sample ages. We find cytosine deamination follows a conventional thermal age model, but we find no correlation between DNA fragmentation and sample age over the timespans analyzed, even when controlling for environmental variables. We propose a model for ancient DNA decay wherein fragmentation rapidly reaches a threshold, then subsequently slows. The observed loss of DNA over time is likely due to a bulk diffusion process, highlighting the importance of tissues and environments creating effectively closed systems for DNA preservation.", "keyphrases": ["ancient dna decay", "dna survival", "fragmentation"]}
{"id": "paleo.002861", "title": "THREE-DIMENSIONAL RECONSTRUCTION OF \"PHYCOSIPHONIFORM\" BURROWS: IMPLICATIONS FOR IDENTIFICATION OF TRACE FOSSILS IN CORE", "abstract": "Phycosiphon-like trace fossils are some of the most common and important ichnofabric forming trace fossils in marine facies. This study was conducted to reconstruct the three-dimensional (3D) morphology of a Phycosiphon-like trace fossil from Cretaceous turbidites in Mexico in order to test the validity of criteria used to recognize such fossils in vertical cross sections similar to those seen in cores through hydrocarbon reservoir intervals. The geometry of the trace fossil was computer-modeled using a series of consecutive images obtained by serial grinding. The recognition of Phycosiphon in cross section is usually based on comparison with hypothetical cross sections of bedding-parallel specimens. The authors critically reassess Phycosiphon-like burrows in the light of existing conceptual and deterministic models, for comparison with three-dimensional reconstruction of Phycosiphon-like trace fossils from the Cretaceous Rosario Formation of Baja California, Mexico.\nObserved morphological differences between our material and typical Phycosiphon suggest that the characteristic \"frogspawn\" ichnofabric that is usually attributed to Phycosiphon (sensu stricto) can be produced by other similar taxa. Our palaeobiological model for the formation of the studied Phycosiphon-like trace fossil is fundamentally different to that proposed for Phycosiphon, but produces remarkably similar vertical cross sections. We consider that identification of Phycosiphon incertum in core is not possible without detailed 3D examination of burrow geometry. We propose the term \"phycosiphoniform\" for this group of ichnofabric-forming trace fossils.", "keyphrases": ["burrow", "identification", "phycosiphon", "three-dimensional reconstruction"]}
{"id": "paleo.012099", "title": "Ediacaran developmental biology", "abstract": "Rocks of the Ediacaran System (635\u2013541 Ma) preserve fossil evidence of some of the earliest complex macroscopic organisms, many of which have been interpreted as animals. However, the unusual morphologies of some of these organisms have made it difficult to resolve their biological relationships to modern metazoan groups. Alternative competing phylogenetic interpretations have been proposed for Ediacaran taxa, including algae, fungi, lichens, rhizoid protists, and even an extinct higher\u2010order group (Vendobionta). If a metazoan affinity can be demonstrated for these organisms, as advocated by many researchers, they could prove informative in debates concerning the evolution of the metazoan body axis, the making and breaking of axial symmetries, and the appearance of a metameric body plan. Attempts to decipher members of the enigmatic Ediacaran macrobiota have largely involved study of morphology: comparative analysis of their developmental phases has received little attention. Here we present what is known of ontogeny across the three iconic Ediacaran taxa Charnia masoni, Dickinsonia costata and Pteridinium simplex, together with new ontogenetic data and insights. We use these data and interpretations to re\u2010evaluate the phylogenetic position of the broader Ediacaran morphogroups to which these taxa are considered to belong (rangeomorphs, dickinsoniomorphs and erniettomorphs). We conclude, based on the available evidence, that the affinities of the rangeomorphs and the dickinsoniomorphs lie within Metazoa.", "keyphrases": ["biology", "body plan", "ediacara biota"]}
{"id": "10.1017/jpa.2021.4", "title": "An updated generic classification of Cenozoic pleurotomariid gastropods, with new records from the Oligocene and early Miocene of India", "abstract": "Abstract. Although taxonomically distinct, the Cenozoic pleurotomariids are the bottlenecked remnants of the Mesozoic members of the family in terms of morphology, with only conical forms surviving the end-Cretaceous mass extinction. Here, we propose an updated classification scheme for the Cenozoic representatives of this group, based on data from the entire Cenozoic pleurotomariid fossil record. We consider all conventional as well as several new characters so that this scheme can readily help to distinguish Cenozoic pleurotomariid genera. Following the new classification scheme, a revision of the generic status of Cenozoic species previously assigned to \u2018Pleurotomaria\u2019 Defrance, 1826 is presented. Only a few Cenozoic pleurotomariid gastropods have been reported from the Indian subcontinent. Here we report four species from the Oligocene of the Kutch Basin and the early Miocene (Burdigalian) of the Dwarka Basin of Gujarat, western India, of which two are described as new: Perotrochus bermotiensis n. sp., Entemnotrochus kathiawarensis n. sp., Entemnotrochus cf. E. bianconii, and Entemnotrochus? sp. 1.", "keyphrases": ["cenozoic pleurotomariid gastropod", "miocene", "india", "marine deposit", "conotomaria"]}
{"id": "paleo.000268", "title": "A bony-crested Jurassic dinosaur with evidence of iridescent plumage highlights complexity in early paravian evolution", "abstract": "The Jurassic Yanliao theropods have offered rare glimpses of the early paravian evolution and particularly of bird origins, but, with the exception of the bizarre scansoriopterygids, they have shown similar skeletal and integumentary morphologies. Here we report a distinctive new Yanliao theropod species bearing prominent lacrimal crests, bony ornaments previously known from more basal theropods. It shows longer arm and leg feathers than Anchiornis and tail feathers with asymmetrical vanes forming a tail surface area even larger than that in Archaeopteryx. Nanostructures, interpreted as melanosomes, are morphologically similar to organized, platelet-shaped organelles that produce bright iridescent colours in extant birds. The new species indicates the presence of bony ornaments, feather colour and flight-related features consistent with proposed rapid character evolution and significant diversity in signalling and locomotor strategies near bird origins.", "keyphrases": ["early paravian evolution", "melanosome", "feather colour"]}
{"id": "paleo.001273", "title": "On the identification of feather structures in stem-line representatives of birds: evidence from fossils and actuopalaeontology", "abstract": "Dinosaurs with fossilized filamentous integument structures are usually preserved in a highly flattened state. Several different feather types have been described on this basis, but the two-dimensional preservation of specimens during fossilization makes the identification of single feather structures difficult due to overlapping feather structures in vivo. Morphological comparison with the diversity of recent feather types is therefore absolutely vital to avoid misinterpretation. To simulate the preservation process, a cadaver of recent Carduelis spinus (European siskin) was flattened in a printing press. Afterwards, the structure of the plumage was compared with the morphology of a single body feather from the same specimen. In comparison with the single feather, the body plumage of the flattened bird looked rather filamentous. It was almost impossible to identify single structures, and in their place, various artefacts were produced. The investigation of plumage in a specimen of the Mesozoic bird Confuciusornis sanctus reveals similar structures. This indicates that flattening of specimens during fossilization amplifies the effect of overlapping among feathers and also causes a loss of morphological detail which can lead to misinterpretations. The results are discussed in connection with some dubious feather morphologies in recently described theropods and basal birds. Based on recent feather morphology, the structure of so-called proximal ribbon-like pennaceous feathers (PRPFs) found in many basal birds is reinterpreted. Furthermore, the morphology of a very similarlooking feather type found in the forelimb and tail of an early juvenile oviraptorosaur is discussed and diagnosed as the first feather generation growing out of the feather sheath. Thus, the whole plumage of this theropod might represent neoptile plumage.", "keyphrases": ["identification", "feather structure", "press", "artefact"]}
{"id": "paleo.009761", "title": "Tectonic blocks and molecular clocks", "abstract": "Evolutionary timescales have mainly used fossils for calibrating molecular clocks, though fossils only really provide minimum clade age constraints. In their place, phylogenetic trees can be calibrated by precisely dated geological events that have shaped biogeography. However, tectonic episodes are protracted, their role in vicariance is rarely justified, the biogeography of living clades and their antecedents may differ, and the impact of such events is contingent on ecology. Biogeographic calibrations are no panacea for the shortcomings of fossil calibrations, but their associated uncertainties can be accommodated. We provide examples of how biogeographic calibrations based on geological data can be established for the fragmentation of the Pangaean supercontinent: (i) for the uplift of the Isthmus of Panama, (ii) the separation of New Zealand from Gondwana, and (iii) for the opening of the Atlantic Ocean. Biogeographic and fossil calibrations are complementary, not competing, approaches to constraining molecular clock analyses, providing alternative constraints on the age of clades that are vital to avoiding circularity in investigating the role of biogeographic mechanisms in shaping modern biodiversity. This article is part of the themed issue \u2018Dating species divergences using rocks and clocks\u2019.", "keyphrases": ["molecular clock", "evolutionary timescale", "tree"]}
{"id": "paleo.012628", "title": "European Bison as a Refugee Species? Evidence from Isotopic Data on Early Holocene Bison and Other Large Herbivores in Northern Europe", "abstract": "According to the refugee species concept, increasing replacement of open steppe by forest cover after the last glacial period and human pressure had together forced European bison (Bison bonasus)\u2014the largest extant terrestrial mammal of Europe\u2014into forests as a refuge habitat. The consequent decreased fitness and population density led to the gradual extinction of the species. Understanding the pre-refugee ecology of the species may help its conservation management and ensure its long time survival. In view of this, we investigated the abundance of stable isotopes (\u03b413C and \u03b415N) in radiocarbon dated skeletal remains of European bison and other large herbivores\u2014aurochs (Bos primigenius), moose (Alces alces), and reindeer (Rangifer tarandus)\u2014from the Early Holocene of northern Europe to reconstruct their dietary habits and pattern of habitat use in conditions of low human influence. Carbon and nitrogen isotopic compositions in collagen of the ungulate species in northern central Europe during the Early Holocene showed significant differences in the habitat use and the diet of these herbivores. The values of the \u03b413C and \u03b415N isotopes reflected the use of open habitats by bison, with their diet intermediate between that of aurochs (grazer) and of moose (browser). Our results show that, despite the partial overlap in carbon and nitrogen isotopic values of some species, Early Holocene large ungulates avoided competition by selection of different habitats or different food sources within similar environments. Although Early Holocene bison and Late Pleistocene steppe bison utilized open habitats, their diets were significantly different, as reflected by their \u03b415N values. Additional isotopic analyses show that modern populations of European bison utilize much more forested habitats than Early Holocene bison, which supports the refugee status of the species.", "keyphrases": ["holocene bison", "northern europe", "habitat use"]}
{"id": "10.1002/ggge.20257", "title": "The Giant Pacific Oyster (Crassostrea gigas) as a modern analog for fossil ostreoids: Isotopic (Ca, O, C) and elemental (Mg/Ca, Sr/Ca, Mn/Ca) proxies", "abstract": "Modern analogs are an essential part of palaeoclimate studies, because they provide the basis for the understanding of geochemical signatures of fossils. Ostreoids are common in many sedimentary sequences and because of their fast growth, high temporal resolution sampling of past seasonal variability is possible. Here, two shell structures of modern Giant Pacific Oysters (Crassostrea gigas), the chalky substance and foliate layers, have been sampled for trace element distributions (Mg, Sr, Mn) and stable isotope variability (C, O, Ca). Oxygen isotopes exhibit a clear seasonal signature. Mean carbon isotope values of different oysters agree within 0.1\u2030, but ontogenic variability is complicated by shell growth patterns and potential small vital effects. The calcium isotope ratios are found to be constant throughout ontogeny within analytical precision at a value of \u03b444/40Ca\u2009=\u20090.68\u2009\u00b1\u20090.16\u2030 (2 sd) SRM\u2013915a which is consistent with other bivalve species. Calcium isotope ratios in oyster shell material might thus be a possible proxy for palaeo seawater calcium isotope ratios. Element/Ca ratios are significantly higher in the chalky substance than in the foliate layers and especially high Sr/Ca and Mn/Ca ratios are observed for the first growth season of the oysters. Mg/Ca ratios in the chalky substance show a negative correlation with \u03b418O values, compatible with a temperature dependence, whereas this correlation is absent in the foliate layers. Seasonal changes of Sr/Ca are controlled by metabolic processes, whereas for Mn/Ca an additional environmental control is evident.", "keyphrases": ["crassostrea gigas", "modern analog", "oyster shell material"]}
{"id": "paleo.003828", "title": "STALKED CRINOID LOCOMOTION, AND ITS ECOLOGICAL AND EVOLUTIONARY IMPLICATIONS", "abstract": "In the past two decades, much direct evidence has been gathered on active crawling by stalked crinoids, a group generally thought to be sessile. Detailed descriptions of crawling mechanics of isocrinids in aquaria revealed only exceedingly slow movements (~0.1 mm sec -1 ). Crawling at such speeds severely restricted the range of roles that this behavior could play in stalked crinoid biology and, consequently, in its potential impact on their ecology and evolutionary history. Here, we provide evidence collected in situ by submersible near Grand Bahama Island at a depth of 420 m for a different mode of crawling in stalked crinoids. Its most striking feature is a speed two orders of magnitude greater (~10-30 mm sec -1 ) than previously observed. The biomechanical cause for the differences in speeds between the two crawling modes is related to the difference in the number of articulations, and thus length of the arm, involved in the power stroke. We suggest that the high speed mode may represent an escape strategy from benthic enemies such as cidaroid echinoids, which occur with stalked crinoids and have been shown to ingest them. A first-order tally of crinoid genera possessing morphological traits required for crawling is provided. Crawling may have characterized some Paleozoic taxa, such as some of the advanced cladids (a group very closely related to post-Paleozoic crinoids), but the Permo-Triassic extinction represents a major threshold between the largely sessile crinoid faunas of the Paleozoic and the increasingly dominant motile crinoids of the post-Paleozoic.", "keyphrases": ["crinoid", "isocrinid", "speed"]}
{"id": "10.1127/0078-0421/2006/0042-0075", "title": "Cyclostratigraphy concepts, definitions, and applications", "abstract": "Cyclostratigraphy is the subdiscipline of stratigraphy that deals with the identification, characterization, correlation, and interpretation of cyclic variations in the stratigraphic record and, in particular, with their application in geochronology by improving the accuracy and resolution of time-stratigraphic frameworks. As such it uses astronomical cycles of known periodicities to date and interpret the sedimentary record. The most important of these cycles are the Earth\u2019s orbital cycles of precession, obliquity, and eccentricity (Milankovitch cycles), which result from perturbations of the Earth\u2019s orbit and its rotational axis. They have periods ranging from 20 to 400 kyr, and even up to millions of years. These cycles translate (via orbital-induced changes in insolation) into climatic, oceanographic, sedimentary, and biological changes that are potentially recorded in the sedimentary archives through geologic time. Many case studies have demonstrated that detailed analysis of the sedimentary record (stacking patterns of beds, disconformities, facies changes, fluctuations in biological composition, and/or changes in geochemical composition) enables identification of these cycles with high confidence. Once the relationship between the sedimentary record and the orbital forcing is established, an unprecedented high time resolution becomes available, providing a precise and accurate framework for the timing of Earth system processes. For the younger part of the geologic past, astronomical time scales have been constructed by tuning cyclic palaeoclimatic records to orbital and insolation target curves; these time scales are directly tied to the Present. In addition, the astronomical tuning has been used to calibrate the 40Ar/39Ar dating method. In the older geologic past, \u201cfloating\u201d astronomical time scales provide a high time resolution for stratigraphic intervals, even if their radiometric age is subject to the error margins of the dating techniques. Because the term \u201csedimentary cycle\u201d is used in many different ways by the geologic community and does not always imply time significance, we propose using \u201castrocycle\u201d once the cycle periodicity has been demonstrated by a thorough cyclostratigraphic analysis. Authors\u2019 addresses: Andr\u00e9 Strasser, Department of Geosciences, University of Fribourg, CH-1700 Fribourg, Switzerland, e-mail: andreas.strasser@unifr.ch; Frederik J. Hilgen, Faculty of Earth Sciences, University of Utrecht, 3584 CD Utrecht, The Netherlands, e-mail: fhilgen@geo.uu.nl; Philip H. Heckel, Department of Geoscience, University of Iowa, Iowa City, Iowa 52242, U.S.A., e-mail: philip-heckel@uiowa.edu DOI: 10.1127/0078-0421/2006/0042-0075 0078-00421/06/0042-0075 $ 10.00 \u00a9 2007 Gebr\u00fcder Borntraeger, D-14129 Berlin \u00b7 D-70176 Stuttgart", "keyphrases": ["application", "sedimentary archive", "archive"]}
{"id": "paleo.001477", "title": "Extinction of herbivorous dinosaurs linked to Early Jurassic global warming event", "abstract": "Sauropods, the giant long-necked dinosaurs, became the dominant group of large herbivores in terrestrial ecosystems after multiple related lineages became extinct towards the end of the Early Jurassic (190\u2013174 Ma). The causes and precise timing of this key faunal change, as well as the origin of eusauropods (true sauropods), have remained ambiguous mainly due to the scarce dinosaurian fossil record of this time. The terrestrial sedimentary successions of the Ca\u00f1ad\u00f3n Asfalto Basin in central Patagonia (Argentina) document this critical interval of dinosaur evolution. Here, we report a new dinosaur with a nearly complete skull that is the oldest eusauropod known to date and provide high-precision U\u2013Pb geochronology that constrains in time the rise of eusauropods in Patagonia. We show that eusauropod dominance was established after a massive magmatic event impacting southern Gondwana (180\u2013184 Ma) and coincided with severe perturbations to the climate and a drastic decrease in the floral diversity characterized by the rise of conifers with small scaly leaves. Floral and faunal records from other regions suggest these were global changes that impacted the terrestrial ecosystems during the Toarcian warming event and formed part of a second-order mass extinction event.", "keyphrases": ["warming event", "terrestrial ecosystem", "eusauropoda"]}
{"id": "paleo.011782", "title": "Neogene sharks and rays from the Brazilian \u2018Blue Amazon\u2019", "abstract": "The lower Miocene Pirabas Formation in the North of Brazil was deposited under influence of the proto-Amazon River and is characterized by large changes in the ecological niches from the early Miocene onwards. To evaluate these ecological changes, the elasmobranch fauna of the fully marine, carbonate-rich beds was investigated. A diverse fauna with 24 taxa of sharks and rays was identified with the dominant groups being carcharhiniforms and myliobatiforms. This faunal composition is similar to other early Miocene assemblages from the proto-Carribbean bioprovince. However, the Pirabas Formation has unique features compared to the other localities; being the only Neogene fossil fish assemblage described from the Atlantic coast of Tropical Americas. Phosphate oxygen isotope composition of elasmobranch teeth served as proxies for paleotemperatures and paleoecology. The data are compatible with a predominantly tropical marine setting with recognized inshore and offshore habitats with some probable depth preferences (e.g., Aetomylaeus groups). Paleohabitat of taxa particularly found in the Neogene of the Americas (\u2020Carcharhinus ackermannii, \u2020Aetomylaeus cubensis) are estimated to have been principally coastal and shallow waters. Larger variation among the few analyzed modern selachians reflects a larger range for the isotopic composition of recent seawater compared to the early Miocene. This probably links to an increased influence of the Amazon River in the coastal regions during the Holocene.", "keyphrases": ["shark", "ray", "isotopic composition"]}
{"id": "paleo.011221", "title": "New evidence of megafaunal bone damage indicates late colonization of Madagascar", "abstract": "The estimated period in which human colonization of Madagascar began has expanded recently to 5000\u20131000 y B.P., six times its range in 1990, prompting revised thinking about early migration sources, routes, maritime capability and environmental changes. Cited evidence of colonization age includes anthropogenic palaeoecological data 2500\u20132000 y B.P., megafaunal butchery marks 4200\u20131900 y B.P. and OSL dating to 4400 y B.P. of the Lakaton\u2019i Anja occupation site. Using large samples of newly-excavated bone from sites in which megafaunal butchery was earlier dated >2000 y B.P. we find no butchery marks until ~1200 y B.P., with associated sedimentary and palynological data of initial human impact about the same time. Close analysis of the Lakaton\u2019i Anja chronology suggests the site dates <1500 y B.P. Diverse evidence from bone damage, palaeoecology, genomic and linguistic history, archaeology, introduced biota and seafaring capability indicate initial human colonization of Madagascar 1350\u20131100 y B.P.", "keyphrases": ["bone damage", "colonization", "madagascar", "butchery mark"]}
{"id": "paleo.012658", "title": "A Systematic Study on Tooth Enamel Microstructures of Lambdopsalis bulla (Multituberculate, Mammalia) - Implications for Multituberculate Biology and Phylogeny", "abstract": "Tooth enamel microstructure is a reliable and widely used indicator of dietary interpretations and data for phylogenetic reconstruction, if all levels of variability are investigated. It is usually difficult to have a thorough examination at all levels of enamel structures for any mammals, especially for the early mammals, which are commonly represented by sparse specimens. Because of the random preservation of specimens, enamel microstructures from different teeth in various species are often compared. There are few examples that convincingly show intraspecific variation of tooth enamel microstructure in full dentition of a species, including multituberculates. Here we present a systematic survey of tooth enamel microstructures of Lambdopsalis bulla, a taeniolabidoid multituberculate from the Late Paleocene Nomogen Formation, Inner Mongolia. We examined enamel structures at all hierarchical levels. The samples are treated differently in section orientations and acid preparation and examined using different imaging methods. The results show that, except for preparation artifacts, the crystallites, enamel types, Schmelzmuster and dentition types of Lambdopsalis are relatively consistent in all permanent teeth, but the prism type, including the prism shape, size and density, may vary in different portions of a single tooth or among different teeth of an individual animal. The most common Schmelzmuster of the permanent teeth in Lambdopsalis is a combination of radial enamel in the inner and middle layers, aprismatic enamel in the outer layer, and irregular decussations in tooth crown area with great curvature. The prism seam is another comparably stable characteristic that may be a useful feature for multituberculate taxonomy. The systematic documentation of enamel structures in Lambdopsalis may be generalized for the enamel microstructure study, and thus for taxonomy and phylogenetic reconstruction, of multituberculates and even informative for the enamel study of other early mammals.", "keyphrases": ["enamel", "lambdopsalis bulla", "bulla", "multituberculate"]}
{"id": "10.1126/sciadv.1701450", "title": "Radiocarbon chronology of Manot Cave, Israel and Upper Paleolithic dispersals", "abstract": "Manot Cave radiocarbon dates establish Levantine chronology, which is critical for understanding Upper Paleolithic dispersals. The timing of archeological industries in the Levant is central for understanding the spread of modern humans with Upper Paleolithic traditions. We report a high-resolution radiocarbon chronology for Early Upper Paleolithic industries (Early Ahmarian and Levantine Aurignacian) from the newly excavated site of Manot Cave, Israel. The dates confirm that the Early Ahmarian industry was present by 46,000 calibrated years before the present (cal BP), and the Levantine Aurignacian occurred at least between 38,000 and 34,000 cal BP. This timing is consistent with proposed migrations or technological diffusions between the Near East and Europe. Specifically, the Ahmarian could have led to the development of the Protoaurignacian in Europe, and the Aurignacian in Europe could have spread back to the Near East as the Levantine Aurignacian.", "keyphrases": ["manot cave", "upper paleolithic dispersal", "early ahmarian"]}
{"id": "10.1080/14772019.2018.1541485", "title": "Morphology, palaeoecology and phylogenetic interpretation of the Cambrian echinoderm Vyscystis (Barrandian area, Czech Republic)", "abstract": "The lepidocystoid echinoderm Vyscystis is known from the mid-Cambrian (Drumian) Jince Formation of the P\u0159\u00edbram-Jince Basin (Czech Republic). Recently collected specimens of this genus, which are very well preserved, provide important new information, resulting in an improved understanding of their morphology (particularly the oral surface), growth trends and an assessment of their phylogenetic position and palaeoecology. Vyscystis is characterized by an aboral imbricate cup and a flattened tessellate oral surface, bearing exotomous curved ambulacra supporting coiled brachioles. A phylogenetic analysis suggests a basal position of lepidocystoids among blastozoans. Vyscystis shares plesiomorphic characters with other lepidocystoids (e.g. calyx) and some edrioasteroids (curvature of the ambulacra). It shows homoplasies (exotomous ambulacral pattern and coiled brachioles) with more derived eocrinoids (e.g. Gogia). Vyscystis was probably a low-level suspension feeder, living attached to hard debris on a soft substrate. Attachment to skeletal fragments was probably achieved by some sort of \u2018biogluing\u2019.", "keyphrases": ["palaeoecology", "echinoderm vyscystis", "phylogenetic analysis"]}
{"id": "10.1017/jpa.2021.22", "title": "New sphenodontian (Reptilia: Lepidosauria) from a novel Late Triassic paleobiota in western North America sheds light on the earliest radiation of herbivorous lepidosaurs", "abstract": "Abstract. Herbivory is a common ecological function among extant lepidosaurs, but little is known about the origin of this feeding strategy within Lepidosauria. Here we describe a sphenodontian (Lepidosauria) from the Late Triassic of western North America, Trullidens purgatorii n. gen. n. sp., that reveals new aspects of the earliest radiation of herbivorous lepidosaurs. This taxon is represented by an isolated lower jaw with robust structure bearing transversely widened dentition and extensive wear facets, suggesting a masticatory apparatus specialized for herbivory. An unusual \u2018incisor-like\u2019 tooth is present at the anterior end of the jaw; a unique feature among lepidosaurs, this tooth is convergent with the incisors of extant rodents and lagomorphs. Phylogenetic analyses support the placement of this taxon within opisthodontian sphenodontians, a group sharing derived cranio-dental morphologies specialized for herbivory. The new taxon was recovered in a recently discovered and unnamed series of Upper Triassic strata in southeastern Colorado, USA, exposed in Canyons incised by the Purgatoire River and its tributaries. These strata comprise a dominantly red-bed sequence of conglomerates, sandstones, and siltstones deposited in a fluvio-lacustrine setting, preserving a Late Triassic biota of invertebrate and vertebrate ichnofossils, plant macrofossils, bony fish, temnospondyl amphibians, and reptiles. We use aetosaur osteoderms as biostratigraphic links to the nearby Chinle Formation of Arizona, USA, establishing a middle Norian age for these strata. The presence of an opisthodontian from western equatorial Pangaea in the Norian Stage reveals a near-global radiation of this clade across the Pangaean supercontinent during the Late Triassic.", "keyphrases": ["sphenodontian", "lepidosauria", "late triassic", "herbivorous lepidosaur"]}
{"id": "10.1029/2012PA002351", "title": "Nutrients as the dominant control on the spread of anoxia and euxinia across the Cenomanian-Turonian oceanic anoxic event (OAE2): Model-data comparison", "abstract": "[1]\u00a0The Cenomanian-Turonian oceanic anoxic event (OAE2) is characterized by large perturbations in the oxygen and sulfur cycles of the ocean, potentially resulting from changes in oxygen supply (via oxygen solubility and ocean circulation) and in marine productivity. We assess the relative impact of these mechanisms, comparing model experiments with a new compilation of observations for seafloor dysoxia/anoxia and photic zone euxinia. The model employed is an intermediate-complexity Earth system model which accounts for the main ocean dynamics and biogeochemistry of the Cretaceous climate. The impact of higher temperature and marine productivity is evaluated in the model as a result of higher atmospheric carbon dioxide and oceanic nutrient concentrations. The model shows that temperature is not alone able to reproduce the observed patterns of oceanic redox changes associated with OAE2. Observations are reproduced in the model mainly via enhanced marine productivity due to higher nutrient content (responsible for 85% of the change). Higher phosphate content could have been sustained by increased chemical weathering and phosphorus regeneration from anoxic sediments, which in turn induced an enhanced nitrogen nutrient content of the ocean via nitrogen fixation. The model also shows that the presence of seafloor anoxia, as suggested by black-shale deposition in the proto-North Atlantic Ocean before the event, might be the result of the silled shape and lack of deep-water formation of this basin at the Late Cretaceous. Overall our model-data comparison shows that OAE2 anoxia was quasi-global spreading from 5% of the ocean volume before the event to at least 50% during OAE2.", "keyphrases": ["anoxia", "oceanic anoxic event", "ocean", "marine productivity"]}
{"id": "10.1002/gj.1082", "title": "The Xichong flora of Yunnan, China: diversity in late Mid Devonian plant assemblages", "abstract": "Over the past 10 years, significant progress has been made in our understanding of late Mid Devonian floras of Yunnan Province, China. Based on new collections and a restudy of existing specimens, most of the old taxa have been emended, and some new taxa described. The late Mid Devonian Xichong flora of Yunnan is dominated by lycopsids, including prelycopsids, homosporous and herbaceous protolepidodendrids. The \u2018fern\u2019\u2010like and cladoxylopsid plants are important and are mainly endemic. A few small plants have also been reported. The Xichong flora is divided into two ecological levels: small tree and ground cover levels. The palaeoclimate of late Mid Devonian Yunnan belonged to the tropical zone. There are noticeable differences between the fossil plants of Yunnan and those of the late Mid Devonian in Laurussia and Venezuela. The Xichong flora is a special, endemic flora in a palaeogeographically isolated tropical area, controlled by local palaeoclimate. The sequence of floras developed in pre\u2010Carboniferous time in South China includes the Posongchong (Pragian), the Xichong (late Givetian) and the Wutung (late Famennian) floras. These floras are treated as pre\u2010Cathaysian floras. Further work is required to establish how much influence these pre\u2010Cathaysian floras had in the Carboniferous\u2010Permian development of the Cathaysian Flora. Copyright \u00a9 2007 John Wiley & Sons, Ltd.", "keyphrases": ["xichong flora", "china", "lycopsid"]}
{"id": "paleo.001234", "title": "The Early Cambrian (Botomian) stem group brachiopod Mickwitzia from Northeast Greenland", "abstract": "The problematic brachiopod Mickwitzia Schmidt, 1888 is re-described based on new material of M. cf. occidens Walcott, 1908 from the Early Cambrian (Botomian) Bastion and Ella Island formations of Northeast Greenland. Etched material demonstrates that Mickwitzia has a lingulid-like juvenile (\"larval\") shell with trails of nick-points, reflecting the movement of marginal setae. Juvenile and early mature ventral valves have a lingulid-like pseudointerarea with a pedicle groove. The shell of M. cf. occidens is only partially phosphatic, in particular around the juvenile-early mature shell in both valves. The phosphatic shell includes at least two types of cylindrical structures: (1) slender columns identical with the columns of acrotretoid brachiopods and (2) relatively thicker tubes which may be open to the exterior surface and have internal striations (on the ventral pseudointerarea). The striations are most likely imprints of microvilli and these tubes can be inferred to have contained setae. The thinner linguliform columns and thicker setigerous striated tubes are considered to be homologous with identical structures in the sellate and mitral sclerites of the problematic Micrina, which has been identified as a probable primitive stem group of the Brachiopoda. Mickwitzia represents a more derived member of the stem group Brachiopoda.", "keyphrases": ["botomian", "northeast greenland", "brachiopoda"]}
{"id": "paleo.008561", "title": "Geographic contingency, not species sorting, dominates macroevolutionary dynamics in an extinct clade of neogastropods (Volutospina; Volutidae)", "abstract": "Abstract. Rates of speciation and extinction are often linked to many ecological factors, traits (emergent and nonemergent) such as environmental tolerance, body size, feeding type, and geographic range. Marine gastropods in particular have been used to examine the role of larval dispersal in speciation. However, relatively few studies have been conducted placing larval modes in species-level phylogenetic context. Those that have, have not incorporated fossil data, while landmark macroevolutionary studies on fossil clades have not considered both phylogenetic context and net speciation (speciation\u2013extinction) rates. This study utilizes Eocene volutid Volutospina species from the U.S. Gulf Coastal Plain and the Hampshire Basin, U.K., to explore the relationships among larval mode, geographic range, and duration. Based on the phylogeny of these Volutospina, we calculated speciation and extinction rates in order to compare the macroevolutionary effects of larval mode. Species with planktotrophic larvae had a median duration of 9.7 Myr, which compared significantly to 4.7 Myr for those with non-planktotrophic larvae. Larval mode did not significantly factor into geographic-range size, but U.S. and U.K. species do differ, indicating a locality-specific component to maximum geographic-range size. Non-planktotrophs (NPTs)were absent among the Volutospina species during the Paleocene\u2013early Eocene. The relative proportions of NPTs increased in the early middle Eocene, and the late Eocene was characterized by disappearance of planktotrophs (PTs). The pattern of observed lineage diversity shows an increasing preponderance of NPTs; however, this is clearly driven by a dramatic extinction of PTs, rather than higher NPT speciation rates during the late Eocene. This study adds nuance to paleontology's understanding of the macroevolutionary consequences of larval mode.", "keyphrases": ["volutospina", "macroevolutionary study", "geographic contingency"]}
{"id": "10.1146/annurev-earth-050212-124217", "title": "Splendid and Seldom Isolated: The Paleobiogeography of Patagonia", "abstract": "The idea that South America was an island continent over most of the Cenozoic, during which its unusual mammalian faunas evolved in isolation, is outstandingly influential in biogeography. Although large numbers of recent fossil discoveries and related advances require that the original isolation concept be significantly modified, it is still repeated in much current literature. The persistence of the idea inspired us to present here an integrated paleobiogeographic account of mammals, reptiles, and plants from the Jurassic to the Paleogene of Patagonia, which has by far the richest fossil record on the continent. All three groups show distribution patterns that are broadly consistent with South America's long separation history, first from Laurasia by the Late Jurassic, then from Africa and India-Madagascar during the late Early Cretaceous, and finally from Antarctica and Australia during the early-middle Eocene, after which \u201cisolation\u201d finally commenced. We highlight areas of promising future research a...", "keyphrases": ["patagonia", "south america", "cenozoic", "fossil discovery"]}
{"id": "10.1242/jeb.118406", "title": "Controlled feeding trials with ungulates: a new application of in vivo dental molding to assess the abrasive factors of microwear", "abstract": "ABSTRACT Microwear, the quantification of microscopic scratches and pits on the occlusal surfaces of tooth enamel, is commonly used as a paleodietary proxy. For ungulates (hoofed mammals), scratch-dominant microwear distinguishes modern grazers from browsers, presumably as a result of abrasion from grass phytoliths (biogenic silica). However, it is also likely that exogenous grit (i.e. soil, dust) is a contributing factor to these scratch-dominant patterns, which may reflect soil ingestion that varies with feeding height and/or environmental conditions (e.g. dust production in open and/or arid habitats). This study assessed the contribution of exogenous grit to tooth wear by measuring the effects of fine- and medium-grained silica sand on tooth enamel using a novel live-animal tooth-molding technique. It therefore constitutes the first controlled feeding experiment using ungulates and the first in vivo experiment using abrasives of different sizes. Four sheep were fed three diet treatments: (1) a mixture of Garrison and Brome hay (control), (2) hay treated with fine-grained silica sand (180\u2013250\u2005\u00b5m) and (3) hay treated with medium-grained silica sand (250\u2013425\u2005\u00b5m). We found a significant increase in pit features that was correlated with an increase in grain size of grit, corroborating earlier chewing simulation experiments that produced pits through grit-induced abrasion (i.e. the \u2018grit effect\u2019). Our results support an interpretation of large silica grains fracturing to create smaller, more abundant angular particles capable of abrasion, with jaw movement defining feature shape (i.e. scratch or pit). Summary: Controlled feeding trials illustrate the effects of exogenous grit on the microscopic tooth wear of hoofed mammals, with implications for paleoecological analyses.", "keyphrases": ["feeding trial", "ungulate", "microwear", "tooth wear", "brome hay"]}
{"id": "paleo.005862", "title": "Fusion Patterns in the Skulls of Modern Archosaurs Reveal That Sutures Are Ambiguous Maturity Indicators for the Dinosauria", "abstract": "The sutures of the skulls of vertebrates are generally open early in life and slowly close as maturity is attained. The assumption that all vertebrates follow this pattern of progressive sutural closure has been used to assess maturity in the fossil remains of non-avian dinosaurs. Here, we test this assumption in two members of the Extant Phylogenetic Bracket of the Dinosauria, the emu, Dromaius novaehollandiae and the American alligator, Alligator mississippiensis, by investigating the sequence and timing of sutural fusion in their skulls. As expected, almost all the sutures in the emu skull progressively close (i.e., they get narrower) and then obliterate during ontogeny. However, in the American alligator, only two sutures out of 36 obliterate completely and they do so during embryonic development. Surprisingly, as maturity progresses, many sutures of alligators become wider in large individuals compared to younger, smaller individuals. Histological and histomorphometric analyses on two sutures and one synchondrosis in an ontogenetic series of American alligator confirmed our morphological observations. This pattern of sutural widening might reflect feeding biomechanics and dietary changes through ontogeny. Our findings show that progressive sutural closure is not always observed in extant archosaurs, and therefore suggest that cranial sutural fusion is an ambiguous proxy for assessing maturity in non-avian dinosaurs.", "keyphrases": ["suture", "maturity", "dinosauria", "sutural closure"]}
{"id": "paleo.012620", "title": "Ardipithecus hand provides evidence that humans and chimpanzees evolved from an ancestor with suspensory adaptations", "abstract": "The suspensory hand of Ardipithecus untangles the relationship between bipedalism and stone tool use in human evolution. The morphology and positional behavior of the last common ancestor of humans and chimpanzees are critical for understanding the evolution of bipedalism. Early 20th century anatomical research supported the view that humans evolved from a suspensory ancestor bearing some resemblance to apes. However, the hand of the 4.4-million-year-old hominin Ardipithecus ramidus purportedly provides evidence that the hominin hand was derived from a more generalized form. Here, we use morphometric and phylogenetic comparative methods to show that Ardipithecus retains suspensory adapted hand morphologies shared with chimpanzees and bonobos. We identify an evolutionary shift in hand morphology between Ardipithecus and Australopithecus that renews questions about the coevolution of hominin manipulative capabilities and obligate bipedalism initially proposed by Darwin. Overall, our results suggest that early hominins evolved from an ancestor with a varied positional repertoire including suspension and vertical climbing, directly affecting the viable range of hypotheses for the origin of our lineage.", "keyphrases": ["chimpanzee", "bipedalism", "early hominin"]}
{"id": "10.2478/geoca-2019-0008", "title": "Sedimentological Characteristics And Paleoenvironmental Implication Of Triassic Vertebrate Localities In Vill\u00e1ny (Vill\u00e1ny Hills, Southern Hungary)", "abstract": "Abstract There are two Triassic vertebrate sites in Vill\u00e1ny Hills (Southern Hungary), where productive and continuous excavations have been carried out in the last six years resulting in a rich and diversified assemblage of shallow marine to coastal animals. The studied formations belong to the Vill\u00e1ny\u2013Bihor Unit of the Tisza Megaunit, which was located at the passive margin of the European Plate during the Triassic. The relatively diverse vertebrate assemblage was collected from a Road-cut on Templom Hill and a newly discovered site at a construction zone located on the Somssich Hill. Four main lithofacies were identified and interpreted in the newly discovered Construction vertebrate site consisting of dolomite (deposited in a shallow, restricted lagoon environment), dolomarl (shallow marine sediments with enhanced terrigenous input), reddish silty claystone (paleosol) and sandstone (terrigenous provenance) indicating that the sediments of the Construction vertebrate site were formed in a subtidal to peritidal zone of the inner ramp environment, where the main controlling factor of the alternating sedimentation was the climate change. However, the recurring paleosol formation in the middle part of the section also indicates a rapid sea-level fall when the marine sediments were repeatedly exposed to subaerial conditions. In the Road-cut site the siliciclastic sediments of the M\u00e9szhegy Sandstone Formation are exposed, representing a nearshore, shallow marine environment characterized by high siliciclastic input from the mainland.", "keyphrases": ["lithofacie", "m\u00e9szhegy sandstone formation", "fossiliferous layer", "depositional environment", "bone-bearing rock"]}
{"id": "paleo.010139", "title": "How many dinosaur species were there? Fossil bias and true richness estimated using a Poisson sampling model", "abstract": "The fossil record is a rich source of information about biological diversity in the past. However, the fossil record is not only incomplete but has also inherent biases due to geological, physical, chemical and biological factors. Our knowledge of past life is also biased because of differences in academic and amateur interests and sampling efforts. As a result, not all individuals or species that lived in the past are equally likely to be discovered at any point in time or space. To reconstruct temporal dynamics of diversity using the fossil record, biased sampling must be explicitly taken into account. Here, we introduce an approach that uses the variation in the number of times each species is observed in the fossil record to estimate both sampling bias and true richness. We term our technique TRiPS (True Richness estimated using a Poisson Sampling model) and explore its robustness to violation of its assumptions via simulations. We then venture to estimate sampling bias and absolute species richness of dinosaurs in the geological stages of the Mesozoic. Using TRiPS, we estimate that 1936 (1543\u20132468) species of dinosaurs roamed the Earth during the Mesozoic. We also present improved estimates of species richness trajectories of the three major dinosaur clades: the sauropodomorphs, ornithischians and theropods, casting doubt on the Jurassic\u2013Cretaceous extinction event and demonstrating that all dinosaur groups are subject to considerable sampling bias throughout the Mesozoic.", "keyphrases": ["true richness", "sampling", "temporal dynamic", "trips", "dinosaur group"]}
{"id": "10.1098/rspb.2008.1075", "title": "Olfactory acuity in theropods: palaeobiological and evolutionary implications", "abstract": "This research presents the first quantitative evaluation of the olfactory acuity in extinct theropod dinosaurs. Olfactory ratios (i.e. the ratio of the greatest diameter of the olfactory bulb to the greatest diameter of the cerebral hemisphere) are analysed in order to infer the olfactory acuity and behavioural traits in theropods, as well as to identify phylogenetic trends in olfaction within Theropoda. A phylogenetically corrected regression of olfactory ratio to body mass reveals that, relative to predicted values, the olfactory bulbs of (i) tyrannosaurids and dromaeosaurids are significantly larger, (ii) ornithomimosaurs and oviraptorids are significantly smaller, and (iii) ceratosaurians, allosauroids, basal tyrannosauroids, troodontids and basal birds are within the 95% CI. Relative to other theropods, olfactory acuity was high in tyrannosaurids and dromaeosaurids and therefore olfaction would have played an important role in their ecology, possibly for activities in low-light conditions, locating food, or for navigation within large home ranges. Olfactory acuity was the lowest in ornithomimosaurs and oviraptorids, suggesting a reduced reliance on olfaction and perhaps an omnivorous diet in these theropods. Phylogenetic trends in olfaction among theropods reveal that olfactory acuity did not decrease in the ancestry of birds, as troodontids, dromaeosaurids and primitive birds possessed typical or high olfactory acuity. Thus, the sense of smell must have remained important in primitive birds and its presumed decrease associated with the increased importance of sight did not occur until later among more derived birds.", "keyphrases": ["theropod", "hemisphere", "olfactory acuity", "great diameter"]}
{"id": "paleo.003266", "title": "Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions", "abstract": "The megatooth shark, Otodus megalodon, is widely accepted as the largest macrophagous shark that ever lived; and yet, despite over a century of research, its size is still debated. The great white shark, Carcharodon carcharias, is regarded as the best living ecological analog to the extinct megatooth shark and has been the basis for all body length estimates to date. The most widely accepted and applied method for estimating body size of O. megalodon was based upon a linear relationship between tooth crown height and total body length in C. carcharias. However, when applying this method to an associated dentition of O. megalodon (UF-VP-311000), the estimates for this single individual ranged from 11.4 to 41.1 m. These widely variable estimates showed a distinct pattern, in which anterior teeth resulted in lower estimates than posterior teeth. Consequently, previous paleoecological analyses based on body size estimates of O. megalodon may be subject to misinterpretation. Herein, we describe a novel method based on the summed crown width of associated fossil dentitions, which mitigates the variability associated with different tooth positions. The method assumes direct proportionality between the ratio of summed crown width to body length in ecologically and taxonomically related fossil and modern species. Total body lengths were estimated from 11 individuals, representing five lamniform species: Otodus megalodon, Otodus chubutensis, Carcharodon carcharias, Carcharodon hubbelli, and Carcharodon hastalis. The method was extrapolated for the largest known isolated upper tooth of O. megalodon, resulting in a maximum body length estimate of 20 m.", "keyphrases": ["otodus", "fossil dentition", "body length"]}
{"id": "paleo.012975", "title": "Tooth fracture frequency in gray wolves reflects prey availability", "abstract": "Exceptionally high rates of tooth fracture in large Pleistocene carnivorans imply intensified interspecific competition, given that tooth fracture rises with increased bone consumption, a behavior that likely occurs when prey are difficult to acquire. To assess the link between prey availability and dental attrition, we documented dental fracture rates over decades among three well-studied populations of extant gray wolves that differed in prey:predator ratio and levels of carcass utilization. When prey:predator ratios declined, kills were more fully consumed, and rates of tooth fracture more than doubled. This supports tooth fracture frequency as a relative measure of the difficulty of acquiring prey, and reveals a rapid response to diminished food levels in large carnivores despite risks of infection and reduced fitness due to dental injuries. More broadly, large carnivore tooth fracture frequency likely reflects energetic stress, an aspect of predator success that is challenging to quantify in wild populations.", "keyphrases": ["prey availability", "interspecific competition", "carcass utilization", "tooth", "wolf"]}
{"id": "paleo.006788", "title": "Revisiting the Estimation of Dinosaur Growth Rates", "abstract": "Previous growth-rate studies covering 14 dinosaur taxa, as represented by 31 data sets, are critically examined and reanalyzed by using improved statistical techniques. The examination reveals that some previously reported results cannot be replicated by using the methods originally reported; results from new methods are in many cases different, in both the quantitative rates and the qualitative nature of the growth, from results in the prior literature. Asymptotic growth curves, which have been hypothesized to be ubiquitous, are shown to provide best fits for only four of the 14 taxa. Possible reasons for non-asymptotic growth patterns are discussed; they include systematic errors in the age-estimation process and, more likely, a bias toward younger ages among the specimens analyzed. Analysis of the data sets finds that only three taxa include specimens that could be considered skeletally mature (i.e., having attained 90% of maximum body size predicted by asymptotic curve fits), and eleven taxa are quite immature, with the largest specimen having attained less than 62% of predicted asymptotic size. The three taxa that include skeletally mature specimens are included in the four taxa that are best fit by asymptotic curves. The totality of results presented here suggests that previous estimates of both maximum dinosaur growth rates and maximum dinosaur sizes have little statistical support. Suggestions for future research are presented.", "keyphrases": ["dinosaur growth rate", "growth-rate study", "error", "mature specimen"]}
{"id": "paleo.012904", "title": "Selective incorporation of proteinaceous over nonproteinaceous cationic amino acids in model prebiotic oligomerization reactions", "abstract": "Significance One of the long-standing questions in origins-of-life research centers on how the proteinaceous side chains and the protein backbone were selected during the earliest phases of evolution. Here we have studied oligomerization reactions of a group of positively charged amino acids, both proteinaceous and nonproteinaceous. Amino acids spontaneously oligomerized without the use of enzymes or activating agents, under mild, hydroxy acid-catalyzed, dry-down conditions. We observed that the proteinaceous amino acids oligomerized more extensively and with greater preference for reactivity through their \u03b1-amine compared with nonproteinaceous amino acids, forming predominantly linear, protein-like backbone topologies. These findings provide a purely chemical basis for selection of the positively charged amino acids found in today\u2019s proteins. Numerous long-standing questions in origins-of-life research center on the history of biopolymers. For example, how and why did nature select the polypeptide backbone and proteinaceous side chains? Depsipeptides, containing both ester and amide linkages, have been proposed as ancestors of polypeptides. In this paper, we investigate cationic depsipeptides that form under mild dry-down reactions. We compare the oligomerization of various cationic amino acids, including the cationic proteinaceous amino acids (lysine, Lys; arginine, Arg; and histidine, His), along with nonproteinaceous analogs of Lys harboring fewer methylene groups in their side chains. These analogs, which have been discussed as potential prebiotic alternatives to Lys, are ornithine, 2,4-diaminobutyric acid, and 2,3-diaminopropionic acid (Orn, Dab, and Dpr). We observe that the proteinaceous amino acids condense more extensively than these nonproteinaceous amino acids. Orn and Dab readily cyclize into lactams, while Dab and Dpr condense less efficiently. Furthermore, the proteinaceous amino acids exhibit more selective oligomerization through their \u03b1-amines relative to their side-chain groups. This selectivity results in predominantly linear depsipeptides in which the amino acids are \u03b1-amine\u2212linked, analogous to today\u2019s proteins. These results suggest a chemical basis for the selection of Lys, Arg, and His over other cationic amino acids for incorporation into proto-proteins on the early Earth. Given that electrostatics are key elements of protein\u2212RNA and protein\u2212DNA interactions in extant life, we hypothesize that cationic side chains incorporated into proto-peptides, as reported in this study, served in a variety of functions with ancestral nucleic acid polymers in the early stages of life.", "keyphrases": ["incorporation", "cationic amino acid", "oligomerization reaction", "depsipeptide", "dry-down reaction"]}
{"id": "10.2110/palo.2011.p11-028r", "title": "DECOMPOSING LITHIFICATION BIAS: PRESERVATION OF LOCAL DIVERSITY STRUCTURE IN RECENTLY CEMENTED STORM-BEACH CARBONATE SANDS, SAN SALVADOR ISLAND, BAHAMAS", "abstract": "ABSTRACT Lithification with related diagenetic phenomena is an important step in a complex transition from living communities to fossil assemblages and a major taphonomic filter distorting the record of past biodiversity. Apart from direct diagenetic culling of fossils, cementation of fossiliferous deposits induces changes in sampling procedures used to extract paleontological data. This study explores the effects of this methodological shift on recorded fine-scale paleoecological patterns by using subfossil mollusk assemblages occurring in the unlithified and recently cemented storm-beach carbonate sands at Sand Dollar Beach, San Salvador Island, Bahamas, which experienced limited diagenetic alteration. Results show that consistent differences in relative abundance patterns of particular taxa can be observed between unlithified and lithified samples due to collection failure. Magnitude of this distortion is controlled in a large part by a degree of transport-related size sorting, with well-sorted assemblages dominated by small gastropods being more affected. This bias, however, is of limited importance and can be mitigated by selective exclusion of the smallest size classes (<5 mm) from the analysis. Moreover, unlithified and poorly lithified deposits record very similar rarefied richness estimates and patterns of diversity partitioning. This contrasts strongly with earlier estimates of lithification-related diversity loss, suggesting greater importance of diagenetic over methodological filters in creating lithification bias observed in the older rock record. Poorly lithified carbonate rocks\u2014present in many late Neogene successions\u2014may yield biodiversity data directly comparable to those recorded by unlithified sediments if careful collecting methods based on bulk samples are employed.", "keyphrases": ["lithification bias", "san salvador island", "unlithified sediment"]}
{"id": "paleo.006348", "title": "Pyritized tube feet in a protasterid ophiuroid from the Upper Ordovician of Kentucky, U.S.A", "abstract": "A single specimen of the protasterid ophiuroid Protasterina flexuosa from the Kope Formation (Cincinnatian, Upper Ordovician) of Kentucky exhibits three-dimensionally pyritized tube feet. This represents the first report of soft-tissue preservation in an echinoderm from the type-Cincinnatian series. The tube feet are solid and lack all internal structure. They consist of aggregated masses of small euhedral to subhedral pyrite crystals suggesting that pyritization, although decay-induced and mediated, did not necessarily replicate soft-tissues but might instead have formed inside the void-spaces left behind during the decay process. The discovery of pyritized soft-tissue as delicate as ophiuroid tube feet suggests that similar forms of soft-tissue preservation might be found in other taxa in the Kope Formation. Perhaps much more importantly, this unexpected occurrence demonstrates the incompleteness of our knowledge of permissible conditions for the preservation of soft-tissues and it thereby indicates promise for discovery of other such occurrences in diverse organisms in unexpected settings. Systematics of Paleozoic ophiuroids remains problematic in spite of many years of study by capable paleontologists. The incomplete but well-preserved specimens treated here include the types of Protasterina flexuosa and Protasterina fimbriata as well as previously undescribed specimens. Together they permit a revised diagnosis and detailed description of the genus Protasterina. Protasterina fimbriata is the type species of the genus but is a subjective junior synonym of Protaster flexuosus (= Protasterina flexuosa). The genus is clearly differentiated from the only other known protasterid ophiuroid from the Cincinnatian series, Taeniaster spinosus, and from all other protasterid genera.", "keyphrases": ["protasterid ophiuroid", "upper ordovician", "cincinnatian", "tube foot"]}
{"id": "10.1002/ajpa.22530", "title": "Technical Note: Calcium and carbon stable isotope ratios as paleodietary indicators.", "abstract": "Calcium stable isotope ratios are hypothesized to vary as a function of trophic level. This premise raises the possibility of using calcium stable isotope ratios to study the dietary behaviors of fossil taxa and to test competing hypotheses on the adaptive origins of euprimates. To explore this concept, we measured the stable isotope composition of contemporary mammals in northern Borneo and northwestern Costa Rica, two communities with functional or phylogenetic relevance to primate origins. We found that bone collagen \u03b4(13) C and \u03b4(15) N values could differentiate trophic levels in each assemblage, a result that justifies the use of these systems to test the predicted inverse relationship between bioapatite \u03b4(13) C and \u03b4(44) Ca values. As expected, taxonomic carnivores (felids) showed a combination of high \u03b4(13) C and low \u03b4(44) Ca values; however, the \u03b4(44) Ca values of other faunivores were indistinguishable from those of primary consumers. We suggest that the trophic insensitivity of most bioapatite \u03b4(44) Ca values is attributable to the negligible calcium content of arthropod prey. Although the present results are inconclusive, the tandem analysis of \u03b4(44) Ca and \u03b4(13) C values in fossils continues to hold promise for informing paleodietary studies and we highlight this potential by drawing attention to the stable isotope composition of the Early Eocene primate Cantius.", "keyphrases": ["calcium", "stable isotope ratio", "trophic level", "consumer"]}
{"id": "paleo.010856", "title": "Early Arrival and Climatically-Linked Geographic Expansion of New World Monkeys from Tiny African Ancestors", "abstract": "&NA; New World Monkeys (NWM) (platyrrhines) are one of the most diverse groups of primates, occupying today a wide range of ecosystems in the American tropics and exhibiting large variations in ecology, morphology, and behavior. Although the relationships among the almost 200 living species are relatively well understood, we lack robust estimates of the timing of origin, ancestral morphology, and geographic range evolution of the clade. Herein, we integrate paleontological and molecular evidence to assess the evolutionary dynamics of extinct and extant platyrrhines. We develop novel analytical frameworks to infer the evolution of body mass, changes in latitudinal ranges through time, and species diversification rates using a phylogenetic tree of living and fossil taxa. Our results show that platyrrhines originated 5\u201010 million years earlier than previously assumed, dating back to the Middle Eocene. The estimated ancestral platyrrhine was small\u2014weighing 0.4 kg\u2014and matched the size of their presumed African ancestors. As the three platyrrhine families diverged, we recover a rapid change in body mass range. During the Miocene Climatic Optimum, fossil diversity peaked and platyrrhines reached their widest latitudinal range, expanding as far South as Patagonia, favored by warm and humid climate and the lower elevation of the Andes. Finally, global cooling and aridification after the middle Miocene triggered a geographic contraction of NWM and increased their extinction rates. These results unveil the full evolutionary trajectory of an iconic and ecologically important radiation of monkeys and showcase the necessity of integrating fossil and molecular data for reliably estimating evolutionary rates and trends.", "keyphrases": ["new world monkeys", "african ancestor", "latitudinal range"]}
{"id": "10.1139/cjes-2013-0185", "title": "The first substantive evidence of Utatsusaurus (Ichthyopterygia) from the Sulphur Mountain Formation (Lower\u2013Middle Triassic) of British Columbia, Canada: a skull roof description in comparison with other early taxa", "abstract": "We describe the skull roof anatomy of PRPRC 2007.08.81, a new specimen of late Olenekian (Spathian) ichthyopterygian from the Vega-Phroso Siltstone Member of the Sulphur Mountain Formation of British Columbia, Canada. Based on the presence of a well-developed anterolateral prefrontal process, parietal that is deeply excavated along its posteromedial margin, and skull roof sutural patterns, PRPRC 2007.08.81 closely resembles other Olenekian forms such as Utatsusaurus, Grippia, Chaohusaurus, and Gulosaurus (a new taxon recently described from British Columbia, Canada). However, due to their shared apomorphic supratemporal terrace morphology, PRPRC 2007.08.81 is identified as Utatsusaurus sp. With the only other known conclusive Utatsusaurus material retrieved from the Osawa Formation (Lower Triassic) of Japan, the broad palaeogeographic distribution of this taxon suggests a radiation event for Ichthyopterygia occurring prior to the latter part of the Olenekian. However, despite this inference, the palaeogeo...", "keyphrases": ["utatsusaurus", "ichthyopterygia", "sulphur mountain formation", "spathian"]}
{"id": "paleo.001724", "title": "HOW BIG WAS 'BIG AL'? QUANTIFYING THE EFFECT OF SOFT TISSUE AND OSTEOLOGICAL UNKNOWNS ON MASS PREDICTIONS FOR ALLOSAURUS (DINOSAURIA:THEROPODA)", "abstract": "MOR693, nicknamed 'Big Al,' is the most complete skeleton of the non-avian theropod Allosaurus and therefore provides the best opportunity to investigate the mass properties of this important Jurassic theropod through accurate physical or digital volumetric models. In this study, laser scanning and computer modelling software have been used to construct volumetric models of MOR693. A long-range laser scanner has been used to digitize the mounted cast of MOR693, allowing the reconstruction of body volumes and respiratory structures around and within the three-dimensional (3D) skeletal model. The digital medium offered the facility to modify model properties nondestructively in a detailed sensitivity analysis to quantify the effects of the many unknown parameters involved in such reconstructions. In addition to varying the volumes of body segments and respiratory structures, we also extend the sensitivity analysis to include uncertainties regarding osteological articulations in non-avian dinosaurs, including effects of inter-vertebral spacing and the orientation or 'flare' of the rib cage in MOR693. Results suggest body mass and inertial values are extremely uncertain and show a wide range in plausible values, whilst the CM (centre of mass) position is well constrained immediately in front and below the hip joint in MOR693, consistent with similar reconstructions of non-avian theropods.", "keyphrases": ["allosaurus", "volume", "sensitivity analysis", "uncertainty", "body mass"]}
{"id": "10.1371/journal.pone.0020834", "title": "The Oldest Anatomically Modern Humans from Far Southeast Europe: Direct Dating, Culture and Behavior", "abstract": "Background Anatomically Modern Humans (AMHs) are known to have spread across Europe during the period coinciding with the Middle to Upper Paleolithic transition. Whereas their dispersal into Western Europe is relatively well established, evidence of an early settlement of Eastern Europe by modern humans are comparatively scarce. Methodology/Principal Finding Based on a multidisciplinary approach for the study of human and faunal remains, we describe here the oldest AMH remains from the extreme southeast Europe, in conjunction with their associated cultural and paleoecological background. We applied taxonomy, paleoecology, and taphonomy combined with geomorphology, stratigraphy, archeology and radiocarbon dating. More than 160 human bone remains have been discovered. They originate from a well documented Upper Paleolithic archeological layer (Gravettian cultural tradition) from the site of Buran-Kaya III located in Crimea (Ukraine). The combination of non-metric dental traits and the morphology of the occipital bones allow us to attribute the human remains to Anatomically Modern Humans. A set of human and faunal remains from this layer has been radiocarbon dated by Accelerator Mass Spectrometry. The direct-dating results of human bone establish a secure presence of AMHs at 31,900+240/\u2212220 BP in this region. They are the oldest direct evidence of the presence of AMHs in a well documented archeological context. Based on taphonomical observations (cut marks and distribution of skeletal elements), they represent the oldest Upper Paleolithic modern humans from Eastern Europe, showing post-mortem treatment of the dead as well. Conclusion/Significance These findings are essential for the debate on the spread of modern humans in Europe during the Upper Paleolithic, as well as their cultural behaviors.", "keyphrases": ["anatomically modern humans", "behavior", "eastern europe", "layer", "old amh"]}
{"id": "paleo.007734", "title": "WILL DOWNS AND THE ZINDA PIR DOME", "abstract": "Will Downs pioneered paleontological study of deposits near Dalana in the Zinda Pir Dome in 1989 and worked there for over a decade thereafter. He was especially skilled in constructing a sequence of microsites spanning the oldest part of the Chitarwata Formation into the lower levels of the Vihowa Formation. The project he inspired also employed magnetostratigraphy to correlate with the Global Polarity Time Scale. At present, fossils remain the most informative indicator of age of the Chitarwata Formation arguing for Oligocene correlation of the base of the section, earliest Miocene for the upper part of the Chitarwata Formation, and early Miocene for the base of the Vihowa Formation, antedating Siwalik deposits on the Potwar Plateau of Pakistan. The magnetostratigraphic data are less conclusive. We developed two alternative interpretations to illustrate constraints on the age of the Chitarwata Formation. One interpretation places the base of the formation in Chron 7Ar, about 25.8 Ma; the other places it in Chron 11n.1r, about 29.8 Ma.", "keyphrases": ["zinda pir dome", "chitarwata formation", "base"]}
{"id": "paleo.011964", "title": "Tracing intensive fish and meat consumption using Zn isotope ratios: evidence from a historical Breton population (Rennes, France)", "abstract": "Here we report Sr and Zn isotope ratios of teeth of medieval to early modern Breton people a population whose diet is known from historical, archeological and collagen isotope data. Most of the population, buried in the Dominican convent of Rennes, France, consists of parliamentary nobles, wealthy commoners and ecclesiastics, who had a diet rich in animal products. Our aim is to assess how the Zn isotope ratios of their teeth compare to those of other French historical populations previously studied, which were characterized by cereal-based diets, and those of modern French individuals, who daily eat animal products. We describe a clear offset (\u223c0.35\u2030) between local and non-local human individuals in Zn isotope ratios. The \u03b466Zntooth values of local individuals overlap that of modern French people, and are lower than those of local carnivores. Non-local \u03b466Zn values are similar to those of historical individuals analyzed previously. We conclude the lower Zn isotope ratios of local humans relative to the associated fauna can be explained by the consumption of carnivorous fish and pork, in agreement with historical, zooarchaeological and collagen (C, N, S) isotope data. Zn isotopes could therefore be a tracer of fish and/or substantial meat consumption in ancient populations.", "keyphrases": ["meat consumption", "france", "\u03b466zn value"]}
{"id": "paleo.008208", "title": "A New Basal Sauropodomorph (Dinosauria: Saurischia) from Quebrada del Barro Formation (Marayes-El Carrizal Basin), Northwestern Argentina", "abstract": "Background Argentinean basal sauropodomorphs are known by several specimens from different basins; Ischigualasto, El Tranquilo, and Mogna. The Argentinean record is diverse and includes some of the most primitive known sauropodomorphs such as Panphagia and Chromogisaurus, as well as more derived forms, including several massospondylids. Until now, the Massospondylidae were the group of basal sauropodomorphs most widely spread around Pangea with a record in almost all continents, mostly from the southern hemisphere, including the only record from Antarctica. Methodology/Principal Finding We describe here a new basal sauropodomorph, Leyesaurus marayensis gen. et sp. nov., from the Quebrada del Barro Formation, an Upper Triassic-Lower Jurassic unit that crops out in northwestern Argentina. The new taxon is represented by a partial articulated skeleton that includes the skull, vertebral column, scapular and pelvic girdles, and hindlimb. Leyesaurus is diagnosed by a set of unique features, such as a sharply acute angle (50 degrees) formed by the ascending process of the maxilla and the alveolar margin, a straight ascending process of the maxilla with a longitudinal ridge on its lateral surface, noticeably bulging labial side of the maxillary teeth, greatly elongated cervical vertebrae, and proximal articular surface of metatarsal III that is shelf-like and medially deflected. Phylogenetic analysis recovers Leyesaurus as a basal sauropodomorph, sister taxon of Adeopapposaurus within the Massospondylidae. Moreover, the results suggest that massospondylids achieved a higher diversity than previously thought. Conclusions/Significance Our phylogenetic results differ with respect to previous analyses by rejecting the massospondylid affinities of some taxa from the northern hemisphere (e.g., Seitaad, Sarahsaurus). As a result, the new taxon Leyesaurus, coupled with other recent discoveries, suggests that the diversity of massospondylids in the southern hemisphere was higher than in other regions of Pangea. Finally, the close affinities of Leyesaurus with the Lower Jurassic Massospondylus suggest a younger age for the Quebrada del Barro Formation than previously postulated.", "keyphrases": ["new basal sauropodomorph", "northwestern argentina", "adeopapposaurus"]}
{"id": "10.1111/sed.12474", "title": "Controls on tidal sedimentation and preservation: Insights from numerical tidal modelling in the Late Oligocene\u2013Miocene South China Sea, Southeast Asia", "abstract": "Numerical tidal modelling, when integrated with other geological datasets, can significantly inform the analysis of physical sedimentation processes and the depositional and preservational record of ancient tide\u2010influenced shoreline\u2013shelf systems. This is illustrated in the Oligo\u2013Miocene of the South China Sea, which experienced significant changes in basin physiography and where tide\u2010influenced, shoreline\u2013shelf deposition is preserved in ca 10 sub\u2010basins. Palaeogeographic reconstructions, palaeotidal modelling and regional sedimentary facies analysis have been integrated in order to evaluate the spatial\u2013temporal evolution and physiographic controls on tidal sedimentation and preservation during the ca 25 Myr Oligo\u2013Miocene record in the South China Sea. Palaeotidal modelling, using an astronomically\u2010forced and global tidal model (Fluidity) at a maximum 10 km resolution, indicates that spring tides along Late Oligocene to Middle Miocene coastlines were predominantly mesotidal\u2013macrotidal and capable of transporting sand, which reflects two main conditions: (i) increased tidal inflow through wider ocean connections to the Pacific Ocean; and (ii) tidal amplification resulting from constriction of the tidal wave in a \u2018blind gulf\u2019 type of basin morphology. Since the Middle to Late Miocene, a reduction in the amplitude and strength of tides in the South China Sea was mainly due to diminishing tidal inflow from the Pacific Ocean caused by the northward movement of the Philippines and Izu\u2013Bonin\u2013Mariana arc. Sensitivity tests to palaeogeographic and palaeobathymetric uncertainty indicate that regional\u2010scale (hundreds to thousands of kilometres) palaeogeographic changes influencing tidal inflow versus outflow can override local\u2010scale (one to hundreds of kilometres) changes to tidal resonance and convergence effects (funnelling and shoaling), such as shelf width and shoreline geometry. Palaeotidal model results compare favourably to the distribution and sedimentary fabric of Oligo\u2013Miocene, tide\u2010influenced, shoreline\u2013shelf successions in peripheral South China Sea basins. However, the preservation potential of tidal deposits is lower in open coastline environments, probably due to enhanced reworking during storms and river floods.", "keyphrases": ["tidal sedimentation", "south china sea", "late miocene"]}
{"id": "paleo.004634", "title": "Ecomorphological diversification of the Late Palaeozoic Palaeodictyopterida reveals different larval strategies and amphibious lifestyle in adults", "abstract": "The Late Palaeozoic insect superorder Palaeodictyopterida exhibits a remarkable disparity of larval ecomorphotypes, enabling these animals to occupy diverse ecological niches. The widely accepted hypothesis presumed that their immature stages only occupied terrestrial habitats, although authors more than a century ago hypothesized they had specializations for amphibious or even aquatic life histories. Here, we show that different species had a disparity of semiaquatic or aquatic specializations in larvae and even the supposed retention of abdominal tracheal gills by some adults. While a majority of mature larvae in Palaeodictyoptera lack unambiguous lateral tracheal gills, some recently discovered early instars had terminal appendages with prominent lateral lamellae like in living damselflies, allowing support in locomotion along with respiratory function. These results demonstrate that some species of Palaeodictyopterida had aquatic or semiaquatic larvae during at least a brief period of their post-embryonic development. The retention of functional gills or gill sockets by adults indicates their amphibious lifestyle and habitats tightly connected with a water environment as is analogously known for some modern Ephemeroptera or Plecoptera. Our study refutes an entirely terrestrial lifestyle for all representatives of the early diverging pterygote group of Palaeodictyopterida, a greatly varied and diverse lineage which probably encompassed many different biologies and life histories.", "keyphrases": ["amphibious lifestyle", "adult", "century"]}
{"id": "10.1111/j.1095-8312.2011.01635.x", "title": "Middle Triassic horseshoe crab reproduction areas on intertidal flats of Europe with evidence of predation by archosaurs", "abstract": "A systematically excavated track site in a 243.5\u00a0Myr old Middle Triassic (Karlstadt Formation, Pelsonian, middle Anisian) intertidal carbonate mud-flat palaeoenvironment at Bernburg (Saxony-Anhalt, central Germany) has revealed extensive horseshoe crab trackways attributable to the KouphichniumNopsca, 1923 ichnogenus. The exposed track bed of a Germanic Basin-wide spanned intertidal megatrack site is a mud-cracked biolaminate surface on which detailed tracks have been preserved because of rapid drying and cementation as a result of high temperatures, followed by rapid covering with a protective layer of arenitic storm or tsunami sediments. The different trackway types and their orientations have allowed a tidal sequence to be reconstructed, with the initial appearance of swimming horseshoe crabs followed by half-swimming/half-hopping limulids under the shallowest water conditions. The Bernburg trackways, which have mapped lengths of up to 40\u00a0m, were all produced by adult animals and exhibit a variety of shapes and patterns that reflect a range of subaquatic locomotion behaviour more typical of mating than of feeding activities. The closest match to the proportions and dimensions of the horseshoe crab tracks at Bernburg is provided by the largest known Middle Triassic limulid Tachypleus gadeai, which is known from the north-western Tethys in Spain. The horseshoe crab body fossils recognized in the German Mesozoic intertidal zones, instead, are from juveniles. The uniformly adult size indicated by the trackways therefore suggests that they may record the oldest intertidal reproductive zones of horseshoe crabs known from anywhere in the world, with the track-makers having possibly migrated thousands of kilometres from shallow marine areas of the north-western Tethys to reproduce in the intertidal palaeoenvironments of the Germanic Basin. Chirotherium trackways of large thecodont archosaurs also appeared on these flats where they appear to have fed on the limulids. With the tidal ebb, smaller reptiles such as Macrocnemus (Rhynchosauroides trackways) appeared on the dry intertidal flats, probably feeding on marine organisms and possibly also on horseshoe crab eggs.\u00a0\u00a9 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103, 76\u2013105.", "keyphrases": ["intertidal flat", "archosaur", "middle triassic"]}
{"id": "10.1073/pnas.1603348113", "title": "Thermogenic methane release as a cause for the long duration of the PETM", "abstract": "Significance The Paleocene\u2013Eocene Thermal Maximum (PETM) was a period of global warming associated with rapid massive 13C-depleted carbon input, often mentioned as a paleoanalog for future climate change and associated feedbacks. One hypothesized carbon source is intrusive volcanism in the North Atlantic region, but rigid dating lacks. We date thermogenic methane release from a hydrothermal vent and find that it postdates the onset of the PETM but correlates to a period of additional carbon injection within the PETM. This study provides evidence of carbon release during the PETM from a reservoir (i.e., organic matter in sedimentary rocks) and implies that carbon release from the vent systems should be included in all future considerations regarding PETM carbon cycling. The Paleocene\u2013Eocene Thermal Maximum (PETM) (\u223c56 Ma) was a \u223c170,000-y (\u223c170-kyr) period of global warming associated with rapid and massive injections of 13C-depleted carbon into the ocean\u2013atmosphere system, reflected in sedimentary components as a negative carbon isotope excursion (CIE). Carbon cycle modeling has indicated that the shape and magnitude of this CIE are generally explained by a large and rapid initial pulse, followed by \u223c50 kyr of 13C-depleted carbon injection. Suggested sources include submarine methane hydrates, terrigenous organic matter, and thermogenic methane and CO2 from hydrothermal vent complexes. Here, we test for the contribution of carbon release associated with volcanic intrusions in the North Atlantic Igneous Province. We use dinoflagellate cyst and stable carbon isotope stratigraphy to date the active phase of a hydrothermal vent system and find it to postdate massive carbon release at the onset of the PETM. Crucially, however, it correlates to the period within the PETM of longer-term 13C-depleted carbon release. This finding represents actual proof of PETM carbon release from a particular reservoir. Based on carbon cycle box model [i.e., Long-Term Ocean\u2013Atmosphere\u2013Sediment Carbon Cycle Reservoir (LOSCAR) model] experiments, we show that 4\u201312 pulses of carbon input from vent systems over 60 kyr with a total mass of 1,500 Pg of C, consistent with the vent literature, match the shape of the CIE and pattern of deep ocean carbonate dissolution as recorded in sediment records. We therefore conclude that CH4 from the Norwegian Sea vent complexes was likely the main source of carbon during the PETM, following its dramatic onset.", "keyphrases": ["petm", "onset", "vent system", "thermogenic methane release"]}
{"id": "10.1080/02724634.2021.2023168", "title": "Diverse Assemblage of Middle Triassic Continental Tetrapods from the Newark Supergroup of Nova Scotia (Canada)", "abstract": "ABSTRACT Triassic strata of the Economy Member of the Wolfville Formation (Newark Supergroup) exposed along the shorelines in Colchester County, Nova Scotia, have yielded an assemblage of continental tetrapods that is clearly different from other Triassic tetrapod communities in eastern North America, including the Late Triassic (Carnian) one from the overlying Evangeline Member of the Wolfville Formation. Although dissociated and fragmentary, the skeletal elements document the presence of a lonchorhynchine trematosaurid and at least two taxa of capitosauroid temnospondyls, procolophonid parareptiles, several taxa of archosauromorph reptiles, and a kannemeyeriiform dicynodont synapsid. Particularly noteworthy is the first definite record of the long-necked archosauromorph Tanystropheus from eastern North America. The strata of the Economy Member were deposited in a semiarid setting but the presence of various temnospondyls indicates the existence of perennial bodies of water. The age of this unit has long been regarded as Middle Triassic (Anisian to Ladinian) based on the tetrapod record, and the present study supports this assessment. The tetrapod assemblage most closely resembles those from the upper Moenkopi Formation of the American Southwest and the upper Middle to Upper Buntsandstein of Germany. The Economy Member is the oldest known Triassic tetrapod-bearing stratigraphic unit as well as the first occurrence of Middle Triassic continental tetrapods in eastern North America.", "keyphrases": ["newark supergroup", "nova scotia", "wolfville formation"]}
{"id": "10.11646/zootaxa.96.1.1", "title": "Venation pattern and revision of Orthoptera sensu nov. and sister groups. Phylogeny of Palaeozoic and Mesozoic Orthoptera sensu nov.", "abstract": "After the revision of several fossils and observations of recent taxa, we propose a new interpretation of the wing venation pattern for the \u2018orthopteroid lineage\u2019. The Orthoptera and several taxa previously assigned to the paraphyletic group \u2018Protorthoptera\u2019 are included in a common clade, Archaeorthoptera taxon nov. The Orthoptera and some closest relative groups are included in the Panorthoptera sensu nov. These assignments are based on new autapomorphies based on venation patterns. A cladistic phylogenetic analysis of the Orthoptera is performed for the first time on the fossil record of this group, based on 74 characters (131 informative states). Three taxa assigned to the Archaeorthoptera nec Panorthoptera compose the outgroup. The ingroup is composed of three Panorthoptera nec Orthoptera and 63 Orthoptera, mainly from the Palaeozoic and Mesozoic. Following this initial phylogeny, we propose several nomenclatural changes; the Ensifera are redefined and the relationships between Caelifera and Ensifera sensu nov., and those between the major clades of modern Ensifera sensu nov., are clarified. Relationships within the \u2018oedischioid\u2019 stem-group remain unclear. The evolution of the venational structures within the Orthoptera is discussed and in this analysis the Orthoptera were not clearly affected by the Permo-Triassic biodiversity \u201ccrisis\u201d. The capacity of the fossil taxa to be used in phylogenetic analyses is discussed, using the example of the \u2018orthopteroid\u2019 insects.", "keyphrases": ["phylogeny", "palaeozoic", "wing venation", "caelifera", "venation pattern"]}
{"id": "10.1080/02724634.2015.1054936", "title": "Nasutoceratops titusi (Ornithischia, Ceratopsidae), a Basal Centrosaurine Ceratopsid from the Kaiparowits Formation, Southern Utah", "abstract": "ABSTRACT The skull and associated postcrania of Nasutoceratops titusi, a basal centrosaurine ceratopsid from the Upper Cretaceous (Campanian) Kaiparowits Formation of Grand Staircase\u2014Escalante National Monument, southern Utah, are herein described. Autapomorphies of this taxon include: an ectonaris that comprises 75% of preorbital skull length; pneumatic nasals; a hyper-robust premaxilla\u2014maxilla contact; a double-faceted, medial flange on the maxilla contributing to the hard palate; and unique supraorbital horncores that are anterolaterally directed, anteriorly curved, torsionally twisted, and relatively enormous. A Bayesian analysis, the first conducted for ceratopsians, is coupled with a parsimony phylogenetic analysis of Centrosaurinae, with both analyses recovering Nasutoceratops as the sister taxon to Avaceratops lammersi from the late Campanian of Montana. Nasutoceratops titusi provides insights into the origins of Centrosaurinae and suggests the existence of a previously unknown clade of short-snouted, long-horned centrosaurines that we here hypothesize to have originated in the southern Western Interior Basin of North America.", "keyphrases": ["basal centrosaurine ceratopsid", "ceratopsian", "nasutoceratops titusi"]}
{"id": "10.1073/pnas.1323666111", "title": "Genomic and cranial phenotype data support multiple modern human dispersals from Africa and a southern route into Asia", "abstract": "Significance Current consensus indicates that modern humans originated from an ancestral African population between \u223c100\u2013200 ka. The ensuing dispersal pattern is controversial, yet has important implications for the demographic history and genetic/phenotypic structure of extant human populations. We test for the first time to our knowledge the spatiotemporal dimensions of competing out-of-Africa dispersal models, analyzing in parallel genomic and craniometric data. Our results support an initial dispersal into Asia by a southern route beginning as early as \u223c130 ka and a later dispersal into northern Eurasia by \u223c50 ka. Our findings indicate that African Pleistocene population structure may account for observed plesiomorphic genetic/phenotypic patterns in extant Australians and Melanesians. They point to an earlier out-of-Africa dispersal than previously hypothesized. Despite broad consensus on Africa as the main place of origin for anatomically modern humans, their dispersal pattern out of the continent continues to be intensely debated. In extant human populations, the observation of decreasing genetic and phenotypic diversity at increasing distances from sub-Saharan Africa has been interpreted as evidence for a single dispersal, accompanied by a series of founder effects. In such a scenario, modern human genetic and phenotypic variation was primarily generated through successive population bottlenecks and drift during a rapid worldwide expansion out of Africa in the Late Pleistocene. However, recent genetic studies, as well as accumulating archaeological and paleoanthropological evidence, challenge this parsimonious model. They suggest instead a \u201csouthern route\u201d dispersal into Asia as early as the late Middle Pleistocene, followed by a separate dispersal into northern Eurasia. Here we test these competing out-of-Africa scenarios by modeling hypothetical geographical migration routes and assessing their correlation with neutral population differentiation, as measured by genetic polymorphisms and cranial shape variables of modern human populations from Africa and Asia. We show that both lines of evidence support a multiple-dispersals model in which Australo-Melanesian populations are relatively isolated descendants of an early dispersal, whereas other Asian populations are descended from, or highly admixed with, members of a subsequent migration event.", "keyphrases": ["dispersal", "southern route", "asia", "drift"]}
{"id": "10.1098/rsbl.2019.0441", "title": "Resilience: nitrogen limitation, mycorrhiza and long-term palaeoecological plant\u2013nutrient dynamics", "abstract": "Ecosystem dynamics are driven by both biotic and abiotic processes, and perturbations can push ecosystems into novel dynamical regimes. Plant\u2013plant, plant\u2013soil and mycorrhizal associations all affect plant ecosystem dynamics; however, the direction and magnitude of these effects vary by context and their contribution to ecosystem resilience over long time periods remains unknown. Here, using a mathematical framework, we investigate the effects of plant feedbacks and mycorrhiza on plant\u2013nutrient interactions. We show evidence for strong nutrient controlled feedbacks, moderation by mycorrhiza and influence on ecological resilience. We use this model to investigate the resilience of a longitudinal palaeoecological birch\u2013\u03b415N interaction to plant\u2013soil feedbacks and mycorrhizal associations. The birch\u2013\u03b415N system demonstrated high levels of resilience. Mycorrhiza were predicted to increase resilience by supporting plant\u2013nitrogen uptake and immobilizing excess nitrogen; in contrast, long-term enrichment in available nitrogen by plant\u2013soil feedbacks is expected to decrease ecological resilience.", "keyphrases": ["mycorrhiza", "feedback", "plant\u2013nutrient interaction", "resilience"]}
{"id": "paleo.012718", "title": "Variation, Variability, and the Origin of the Avian Endocranium: Insights from the Anatomy of Alioramus altai (Theropoda: Tyrannosauroidea)", "abstract": "The internal braincase anatomy of the holotype of Alioramus altai, a relatively small-bodied tyrannosauroid from the Late Cretaceous of Mongolia, was studied using high-resolution computed tomography. A number of derived characters strengthen the diagnosis of this taxon as both a tyrannosauroid and a unique, new species (e.g., endocranial position of the gasserian ganglion, internal ramification of the facial nerve). Also present are features intermediate between the basal theropod and avialan conditions that optimize as the ancestral condition for Coelurosauria\u2014a diverse group of derived theropods that includes modern birds. The expression of several primitive theropod features as derived character states within Tyrannosauroidea establishes previously unrecognized evolutionary complexity and morphological plasticity at the base of Coelurosauria. It also demonstrates the critical role heterochrony may have played in driving patterns of endocranial variability within the group and potentially reveals stages in the evolution of neuroanatomical development that could not be inferred based solely on developmental observations of the major archosaurian crown clades. We discuss the integration of paleontology with variability studies, especially as applied to the nature of morphological transformations along the phylogenetically long branches that tend to separate the crown clades of major vertebrate groups.", "keyphrases": ["variability", "tyrannosauroidea", "theropod"]}
{"id": "paleo.006054", "title": "The Miocene Tagay locality of Olkhon Island (Lake Baikal, Eastern Siberia)a multidisciplinary approach", "abstract": "Lake Baikal is the largest intracontinental freshwater basin of Central Asia and the deepest lake on earth. It stands out for its geologic history ranging back to the Late Cretaceous, and for the development of its unique aquatic fauna including numerous endemic elements (Mats et al. 2011) . The biggest island of Lake Baikal, the Olkhon Island, is part of the Baikal National Park, which is included in the list of the UNESCO World Heritage Sites (Fig. 1 ).\nIn Paleogene and Neogene times the Olkhon Island was still part of the Siberian mainland at the western margin of the Baikal depression. Similar geologic and geomorphologic features characterise the landscapes, such as denudated plateaus, where streams had deeply cut into the crystalline basement. The valleys and shallow basins were filled by reworked terrigenous sediments, locally producing rich fossil deposits. The uplift of landscapes around the Baikal depression and deepening of Lake Baikal was driven by tectonic processes in the course of the Neogene. Successively, the Olkhon Island started to separate from the Siberian hinterland, and became completely isolated during the Pleistocene (Mats et al. 2011) .\nTagay, one of the most important Miocene fossil sites, is located at the Tagay Bay of Lake Baikal, at the north-western part of Olkhon Island. For a long time this region has been known for its interesting geology and geomorphology and for the highly diverse fossil fauna and flora preserved in lacustrine sediments of the Miocene Tagay Formation (Logatchev et al.", "keyphrases": ["olkhon island", "issue", "mylagaulidae", "fossiliferous horizon", "rodent fauna"]}
{"id": "10.1130/B35646.1", "title": "A Chronostratigraphic Framework for the Rise of the Ediacaran Macrobiota: New Constraints from Mistaken Point Ecological Reserve, Newfoundland", "abstract": "\n The Conception and St. John\u2019s Groups of southeastern Newfoundland contain some of the oldest known fossils of the Ediacaran macrobiota. The Mistaken Point Ecological Reserve UNESCO World Heritage Site is an internationally recognized locality for such fossils and hosts early evidence for both total group metazoan body fossils and metazoan-style locomotion. The Mistaken Point Ecological Reserve sedimentary succession includes \u223c1500 m of fossil-bearing strata containing numerous dateable volcanogenic horizons, and therefore offers a crucial window into the rise and diversification of early animals. Here we present six stratigraphically coherent radioisotopic ages derived from zircons from volcanic tuffites of the Conception and St. John\u2019s Groups at Mistaken Point Ecological Reserve. The oldest architecturally complex macrofossils, from the upper Drook Formation, have an age of 574.17 \u00b1 0.66 Ma (including tracer calibration and decay constant uncertainties). The youngest rangeomorph fossils from Mistaken Point Ecological Reserve, in the Fermeuse Formation, have a maximum age of 564.13 \u00b1 0.65 Ma. Fossils of the famous \u201cE\u201d Surface are confirmed to be 565.00 \u00b1 0.64 Ma, while exceptionally preserved specimens on the \u201cBrasier\u201d Surface in the Briscal Formation are dated at 567.63 \u00b1 0.66 Ma. We use our new ages to construct an age-depth model for the sedimentary succession, constrain sedimentary accumulation rates, and convert stratigraphic fossil ranges into the time domain to facilitate integration with time-calibrated data from other successions. Combining this age model with compiled stratigraphic ranges for all named macrofossils within the Mistaken Point Ecological Reserve succession, spanning 76 discrete fossil-bearing horizons, enables recognition and interrogation of potential evolutionary signals. Peak taxonomic diversity is recognized within the Mistaken Point and Trepassey Formations, and uniterminal rangeomorphs with undisplayed branching architecture appear several million years before multiterminal, displayed forms. Together, our combined stratigraphic, paleontological, and geochronological approach offers a holistic, time-calibrated record of evolution during the mid\u2013late Ediacaran Period and a framework within which to consider other geochemical, environmental, and evolutionary data sets.", "keyphrases": ["ediacaran macrobiota", "newfoundland", "zircon"]}
{"id": "10.1073/pnas.1501529112", "title": "New chronology for Ks\u00e2r \u2018Akil (Lebanon) supports Levantine route of modern human dispersal into Europe", "abstract": "Significance Bayesian modeling of AMS radiocarbon dates on the marine mollusk Phorcus turbinatus from Ks\u00e2r \u2018Akil (Lebanon) indicates that the earliest presence of Upper Paleolithic (UP) modern humans in the Levant predates 45,900 cal B.P. Similarities in early UP lithic technology and material culture suggest population dispersals between the Levant and Europe around 50,000\u201340,000 cal B.P. Our data confirm the presence of modern humans carrying a UP toolkit in the Levant prior to any known European modern human fossils and allow rejection of recent claims that European UP modern humans predate those in the Levant. This result, in turn, suggests the Levant served as a corridor for the dispersal of modern humans out of Africa and into Eurasia. Modern human dispersal into Europe is thought to have occurred with the start of the Upper Paleolithic around 50,000\u201340,000 y ago. The Levantine corridor hypothesis suggests that modern humans from Africa spread into Europe via the Levant. Ks\u00e2r \u2018Akil (Lebanon), with its deeply stratified Initial (IUP) and Early (EUP) Upper Paleolithic sequence containing modern human remains, has played an important part in the debate. The latest chronology for the site, based on AMS radiocarbon dates of shell ornaments, suggests that the appearance of the Levantine IUP is later than the start of the first Upper Paleolithic in Europe, thus questioning the Levantine corridor hypothesis. Here we report a series of AMS radiocarbon dates on the marine gastropod Phorcus turbinatus associated with modern human remains and IUP and EUP stone tools from Ks\u00e2r \u2018Akil. Our results, supported by an evaluation of individual sample integrity, place the EUP layer containing the skeleton known as \u201cEgbert\u201d between 43,200 and 42,900 cal B.P. and the IUP-associated modern human maxilla known as \u201cEthelruda\u201d before \u223c45,900 cal B.P. This chronology is in line with those of other Levantine IUP and EUP sites and demonstrates that the presence of modern humans associated with Upper Paleolithic toolkits in the Levant predates all modern human fossils from Europe. The age of the IUP-associated Ethelruda fossil is significant for the spread of modern humans carrying the IUP into Europe and suggests a rapid initial colonization of Europe by our species.", "keyphrases": ["chronology", "ks\u00e2r", "modern human dispersal", "colonization"]}
{"id": "10.1002/ajpa.23815", "title": "Dental microwear texture analysis of Homo sapiens sapiens: Foragers, farmers, and pastoralists.", "abstract": "OBJECTIVES\nThe current study seeks to determine if a sample of foragers, farmers, and pastoralists are distinguishable based on their dental microwear texture signatures.\n\n\nMATERIALS AND METHODS\nThe study included a sample of 719 individuals from 51 archeological sites (450 farmers, 192 foragers, 77 pastoralists). All were over age 12 and sexes were pooled. Using a Sensofar\u00ae white-light confocal profiler we collected dental microwear texture analysis (DMTA) data from a single first or second molar from each individual. We leveled and cleaned data clouds following standard procedures and analyzed the data with Sfrax\u00ae and Toothfrax\u00ae software. The DMTA variables were complexity and anisotropy. Statistics included ANOVA with partial eta squared and Hedges's g. We also performed a follow-up K-means cluster analysis.\n\n\nRESULTS\nWe found significant differences between foragers and farmers and pastoralists for complexity and anisotropy, with foragers having greater complexity than either the farmers or the pastoralists. The farmers and pastoralists had greater anisotropy than the foragers. The Old World foragers had significantly higher anisotropy values than New World foragers. Old and New World farmers did not differ. Among the Old World farmers, those dating from the Neolithic through the Late Bronze Age had higher complexity values than those from the Iron Age through the medieval period. The cluster analysis discerned foragers and farmers but also indicated similarity between hard food foragers and hard food farmers.\n\n\nDISCUSSION\nOur findings reaffirm that DMTA is capable of distinguishing human diets. We found that foragers and farmers, in particular, differ in their microwear signatures across the globe. There are some exceptions, but nothing that would be unexpected given the range of human diets and food preparation techniques. This study indicates that in general DMTA is an efficacious means of paleodietary reconstruction in humans.", "keyphrases": ["forager", "pastoralist", "dental microwear", "microwear pattern", "dietary habit"]}
{"id": "10.1666/12-042.1", "title": "Early Asterozoan (Echinodermata) Diversification: A Paleontologic Quandary", "abstract": "Abstract The Asterozoa as traditionally recognized is monophyletic, although ancestry within the Echinodermata is unknown. The asterozoan class Somasteroidea is most readily recognized by presence of series of simple ossicles termed virgals that extend laterally from each ambulacral ossicle. Virgal series reduction to two or three together with ossicular specializations provide apomorphies of the class Stenuroidea (new ranking). Both asteroid-like and ophiuroid-like configurations as well as expressions less suggestive of those of the surviving classes emerged within stenuroids during an early period of diversification. The classes Ophiuroidea and Asteroidea are separate lineages marked by virgal series reduction to a single ossicle and other ambulacral column specializations. It is uncertain whether one or both surviving classes were derived directly from somasteroids or originated through stenuroids. All three of the derived asterozoan classes can be argued to be either monophyletic and thereby justifying class status, or alternatively either paraphyletic or polyphyletic and thereby indicative of multiple plesions; here, monophyletic class-level status is favored for all three.", "keyphrases": ["echinodermata", "diversification", "asteroidea"]}
{"id": "paleo.009624", "title": "Evolution of high tooth replacement rates in theropod dinosaurs", "abstract": "Tooth replacement rate is an important contributor to feeding ecology for polyphyodont animals. Dinosaurs exhibit a wide range of tooth replacement rates, mirroring their diverse craniofacial specializations, but little is known about broad-scale allometric or evolutionary patterns within the group. In the current broad but sparse dinosaurian sample, only three non-avian theropod tooth replacement rates have been estimated. We estimated tooth formation and replacement rates in three additional non-avian theropod dinosaurs, the derived latest Cretaceous abelisaurid Majungasaurus and the more generalized Late Jurassic Allosaurus and Ceratosaurus. We created the largest dental histological and CT dataset for any theropod dinosaur, sectioning and scanning over a dozen toothed elements of Majungasaurus and several additional elements from the other two genera. Using this large sample, we created models of tooth formation time that allow for theropod replacement rates to be estimated non-destructively. In contrast to previous results for theropods, we found high tooth replacement rates in all three genera, with Allosaurus and Ceratosaurus rates of ~100 days and 56 days for Majungasaurus. The latter rate is on par with those of derived herbivorous dinosaurs including some neosauropods, hadrosaurids, and ceratopsians. This elevated rate may be a response to high rates of tooth wear in Majungasaurus. Within Dinosauria, there is no relationship between body mass and tooth replacement rate and no trends in replacement rate over time. Rather, tooth replacement rate is clade-specific, with elevated rates in abelisaurids and diplodocoids and lower rates in coelurosaurs.", "keyphrases": ["tooth replacement rate", "theropod dinosaur", "dinosauria", "body mass", "tooth development"]}
{"id": "paleo.003211", "title": "CASTING, REPLICATION, AND ANAGLYPH STEREO IMAGING OF MICROSCOPIC DETAIL IN FOSSILS, WITH EXAMPLES FROM CONODONTS AND OTHER JAWLESS VERTEBRATES", "abstract": "Sophisticated techniques, such as computed tomography and scanning light microscopy, now allow palaeontologists to image the microscopic details of fossils even when scanning electron microscopy cannot be used. Occasionally these techniques are not always applicable, and where this is the case, methods involving fossil replication offer an alternative. I describe here a series of techniques for moulding, casting, imaging, and three-dimensional illustration of microfossils (or microscopic details of larger fossils). For moulding fossils (or casting mouldic specimens), room temperature vulcanizing silicon rubber provides a strong and flexible medium with low levels of shrinkage. RTV rubbers are also capable of replicating microscopic details of only a few micrometres. Similarly, epoxy resins are rigid, durable, and long lasting. In combination with RTV silicon rubber moulds, epoxy casts offer higher levels of resolution than any other medium. Details of specific RTV rubbers and epoxy resins that are widely available and work well with small fossils are provided.\nFor imaging, the advantages of stereophotography to illustrate fossils have long been appreciated, but the use of stereo-pairs is limited by their maximum size (generally only 5 or 6 centimetres). With the widespread availability of powerful image editing software, it is now a straightforward matter to produce anaglyph stereo images of any size. I provide step-by-step instructions and a set of actions to automate the process in Adobe Photoshop\u00ae. Anaglyph stereo images can be extremely useful research tools in their own right, but combined with electronic communication and publication they offer a simple and inexpensive means for illustrating fossils, and their microscopic details, in three-dimensions.", "keyphrases": ["microscopic detail", "conodont", "advantage", "instruction"]}
{"id": "10.1139/E08-027", "title": "Late Pleistocene northward-dispersing Bison antiquus from the Bighill Creek Formation, Gallelli Gravel Pit, Alberta, Canada, and the fate of Bison occidentalis", "abstract": "Late Pleistocene bison skeletal remains from the Gallelli Gravel Pit in the Bighill Creek Formation at Calgary, Alberta, document at least two individuals, including the largest postglacial bison reported from North America south of Beringia. Two partial crania, dated to 11 290 and 10 100 14 C years BP, are referred to the southern species Bison antiquus Leidy, indicating northward movement from the midcontinent as ice retreat opened a corridor between Laurentide and Cor- dilleran ice. Their large size suggests a dispersal phenotype exploiting newly available territory. DNA evidence links the 11 290-year-old bison to Clade 1, which includes modern B. bison. This supports in situ evolution of B. bison from B. antiquus through the intermediate usually called B.''occidentalis''. Bison of B. ''occidentalis'' character appeared in Al- berta about 10 ka BP, and the DNA evidence counters the suggestion of a migratory wave from Beringia. The B. occiden- talis type specimen is from Alaska, so this name may be inappropriate for southern populations. Radiocarbon dates suggest that the Bighill Creek Formation paleofauna comprises two faunules separated in time by the Younger Dryas cli- matic episode. Resume\u00b4 : Les restes de squelettes de bisons datant du Pleistocene tardif trouves dans la graviere Gallelli dans la Formation de Bighill Creek aCalgary, en Alberta, representent au moins deux individus, dont le plus gros bison postglaciaire trouve\u00b4 en Amerique du Nord au sud de la Beringie. Deux cranes partiels, datesa ` 11 290 et 10 100 annees 14 C avant le present correspondraient a l'espece meridionale Bison antiquus Leidy, indiquant un mouvement vers le nord a partir du milieu du continent alors que le retrait de la glace ouvrait un corridor entre la glace laurentidienne et la glace de la Cordillere. Leur grande taille suggere un phenotype de dispersion exploitant un territoire recemment disponible. Les preuves fournies par l'ADN relient le bison de 11 290 ans au Clade 1, lequel comprend le B. bison moderne. Cela soutient l'evolution in situ du B. bison apartir de B. antiquus en passant par l'intermediaire habituellement appeleB. \u00ab occidentalis \u00bb. Un bison B. \u00ab occidentalis \u00bb s'est retrouveen Alberta il y environ 10 ka avant le present et les preuves d'ADN opposent la suggestion d'une vague migratoire a partir de la Beringie. Le specimen de type B. occidentalis provient de l'Alaska; ce nom ne con- viendrait donc pas aux populations du sud. Selon les datations au radiocarbone, la paleofaune de la Formation de Bighill Creek comprendrait deux faunules separees dans le temps par l'episode climatique du Dryas recent. (Traduit par la Redaction)", "keyphrases": ["bison", "bighill creek formation", "gallelli gravel pit", "alberta"]}
{"id": "10.1002/2013JC009594", "title": "Twentieth century sea surface temperature and salinity variations at Timor inferred from paired coral \u03b418O and Sr/Ca measurements", "abstract": "The Indonesian Throughflow (ITF), which represents the global ocean circulation connecting the Pacific Warm Pool to the Indian Ocean, strongly influences the Indo-Pacific climate. ITF monitoring since the late 1990s using mooring buoys have provided insights on seasonal and interannual time scales. However, the absence of longer records limits our perspective on its evolution over the past century. Here, we present sea surface temperature (SST) and salinity (SSS) proxy records from Timor Island located at the ITF exit passage via paired coral \u03b418O and Sr/Ca measurements spanning the period 1914\u20132004. These high-resolution proxy based climate data of the last century highlights improvements and cautions when interpreting paleoclimate records of the Indonesian region. If the seasonality of SST and SSS is not perfectly in phase, the application of coral Sr/Ca thermometry improves SST reconstructions compared to estimates based on coral \u03b418O only. Our records also underline the importance of ocean advection besides rainfall on local SSS in the region. Although the El Nino/Southern Oscillation (ENSO) causes larger anomalies relative to the Indian Ocean Dipole (IOD), Timor coral-based SST and SSS records robustly correlate with IOD on interannual time scales, whereas ENSO only modifies Timor SST. Similarly, Timor SST and SSS are strongly linked to Indian Ocean decadal-scale variations that appear to lead Timor oceanographic conditions by about 1.6\u20132 years. Our study sheds new light on the complex signatures of Indo-Pacific climate modes on SST and SSS dynamics of the ITF.", "keyphrases": ["timor", "coral \u03b418o", "indian ocean", "sss"]}
{"id": "paleo.000232", "title": "High Diversity, Low Disparity and Small Body Size in Plesiosaurs (Reptilia, Sauropterygia) from the Triassic\u2013Jurassic Boundary", "abstract": "Invasion of the open ocean by tetrapods represents a major evolutionary transition that occurred independently in cetaceans, mosasauroids, chelonioids (sea turtles), ichthyosaurs and plesiosaurs. Plesiosaurian reptiles invaded pelagic ocean environments immediately following the Late Triassic extinctions. This diversification is recorded by three intensively-sampled European fossil faunas, spanning 20 million years (Ma). These provide an unparalleled opportunity to document changes in key macroevolutionary parameters associated with secondary adaptation to pelagic life in tetrapods. A comprehensive assessment focuses on the oldest fauna, from the Blue Lias Formation of Street, and nearby localities, in Somerset, UK (Earliest Jurassic: 200 Ma), identifying three new species representing two small-bodied rhomaleosaurids (Stratesaurus taylori gen et sp. nov.; Avalonnectes arturi gen. et sp. nov) and the most basal plesiosauroid, Eoplesiosaurus antiquior gen. et sp. nov. The initial radiation of plesiosaurs was characterised by high, but short-lived, diversity of an archaic clade, Rhomaleosauridae. Representatives of this initial radiation were replaced by derived, neoplesiosaurian plesiosaurs at small-medium body sizes during a more gradual accumulation of morphological disparity. This gradualistic modality suggests that adaptive radiations within tetrapod subclades are not always characterised by the initially high levels of disparity observed in the Paleozoic origins of major metazoan body plans, or in the origin of tetrapods. High rhomaleosaurid diversity immediately following the Triassic-Jurassic boundary supports the gradual model of Late Triassic extinctions, mostly predating the boundary itself. Increase in both maximum and minimum body length early in plesiosaurian history suggests a driven evolutionary trend. However, Maximum-likelihood models suggest only passive expansion into higher body size categories.", "keyphrases": ["plesiosaur", "late triassic", "plesiosauria"]}
{"id": "10.4319/lo.1999.44.8.1968", "title": "The fate of nitrogen in the Orbulina universa foraminifera\u2010symbiont system determined by nitrogen isotope analyses of shell\u2010bound organic matter", "abstract": "To trace the flow of nitrogen through the foraminifera\u2010symbiont system, juvenile specimens of the symbiont\u2010bearing planktonic foraminifera, Orbulina universa were collected by SCUBA divers off the coast of Santa Catalina Island, California, and grown in filtered seawater solutions spiked with 15N\u2010labeled nitrate. Our work isolated each pathway of this symbiotic system to determine the amount of nitrogen translocated to the foraminifera from its endosymbionts and its captured diet. Our model results show that when the nitrate uptake by the symbionts is at a maximum, between 50 and 57% of the foraminiferal nitrogen was translocated from the symbionts and the remainder was derived from the captured diet. In nitrate\u2010deficient environments, when the symbiont nitrate uptake was at a minimum, \u223c90\u2013100% of the nitrogen was transferred to the foraminifer by the symbionts from the recycled nitrogen (NH4+) pool. In nitrate\u2010deficient conditions, the primary role of the captured diet may be to provide the system with phosphorous. Highly efficient nutrient use is particularly important to the foraminifera\u2010symbiont system, especially when nutrient concentrations are low. The results indicate a limited correlation between the isotopic composition of the NO3\u2212 in the culture solutions and the \u039415n values of the foraminifera. However, the \u03b415n values of the foraminifera much more strongly reflect the \u03b415n values of the NH4+ recycled through the system. It appears that recycled nitrogen (NH4+) is a more important source of nitrogen to the symbionts and the foraminifera than nitrate; therefore, the \u03b415n values of the foraminifera may not reflect the isotopic composition of the surface\u2010water nutrients. Understanding the nitrogen flow within modern foraminifera\u2010symbiont associations is also important to ancient marine systems, because symbiont\u2010bearing foraminifera are ubiquitous in the fossil record. This study shows that analysis of individual, symbiont\u2010bearing foraminifera species is a necessary first step toward the development of more reliable use of nitrogen isotopes for paleoceanographic reconstructions.", "keyphrases": ["nitrogen", "foraminifera\u2010symbiont system", "foraminifera", "endosymbiont"]}
{"id": "paleo.004037", "title": "The craniomandibular anatomy of the early archosauriform Euparkeria capensis and the dawn of the archosaur skull", "abstract": "Archosauria (birds, crocodilians and their extinct relatives) form a major part of terrestrial ecosystems today, with over 10 000 living species, and came to dominate the land for most of the Mesozoic (over 150 Myr) after radiating following the Permian\u2013Triassic extinction. The archosaur skull has been essential to this diversification, itself diversified into myriad forms. The archosauriform Euparkeria capensis from the Middle Triassic (Anisian) of South Africa has been of great interest since its initial description in 1913, because its anatomy shed light on the origins and early evolution of crown Archosauria and potentially approached that of the archosaur common ancestor. Euparkeria has been widely used as an outgroup in phylogenetic analyses and when investigating patterns of trait evolution among archosaurs. Although described monographically in 1965, subsequent years have seen great advances in the understanding of early archosaurs and in imaging techniques. Here, the cranium and mandible of Euparkeria are fully redescribed and documented using all fossil material and computed tomographic data. Details previously unclear are fully described, including vomerine dentition, the epiptergoid, number of premaxillary teeth and palatal arrangement. A new diagnosis and cranial and braincase reconstruction is provided, and an anatomical network analysis is performed on the skull of Euparkeria and compared with other amniotes. The modular composition of the cranium suggests a flexible skull well adapted to feeding on agile food, but with a clear tendency towards more carnivorous behaviour, placing the taxon at the interface between ancestral diapsid and crown archosaur ecomorphology, corresponding to increases in brain size, visual sensitivity, upright locomotion and metabolism around this point in archosauriform evolution. The skull of Euparkeria epitomizes a major evolutionary transition, and places crown archosaur morphology in an evolutionary context.", "keyphrases": ["anatomy", "archosauriform euparkeria capensis", "archosaur skull", "archosauria"]}
{"id": "paleo.004232", "title": "Terrestrial Origin of Viviparity in Mesozoic Marine Reptiles Indicated by Early Triassic Embryonic Fossils", "abstract": "Viviparity in Mesozoic marine reptiles has traditionally been considered an aquatic adaptation. We report a new fossil specimen that strongly contradicts this traditional interpretation. The new specimen contains the oldest fossil embryos of Mesozoic marine reptile that are about 10 million years older than previous such records. The fossil belongs to Chaohusaurus (Reptilia, Ichthyopterygia), which is the oldest of Mesozoic marine reptiles (ca. 248 million years ago, Early Triassic). This exceptional specimen captures an articulated embryo in birth position, with its skull just emerged from the maternal pelvis. Its headfirst birth posture, which is unlikely to be a breech condition, strongly indicates a terrestrial origin of viviparity, in contrast to the traditional view. The tail-first birth posture in derived ichthyopterygians, convergent with the conditions in whales and sea cows, therefore is a secondary feature. The unequivocally marine origin of viviparity is so far not known among amniotes, a subset of vertebrate animals comprising mammals and reptiles, including birds. Therefore, obligate marine amniotes appear to have evolved almost exclusively from viviparous land ancestors. Viviparous land reptiles most likely appeared much earlier than currently thought, at least as early as the recovery phase from the end-Permian mass extinction.", "keyphrases": ["viviparity", "early triassic", "ichthyopterygian", "terrestrial origin"]}
{"id": "10.1130/G32529.1", "title": "Global decline in ocean ventilation, oxygenation, and productivity during the Paleocene-Eocene Thermal Maximum: Implications for the benthic extinction", "abstract": "The prominent global warming event at the Paleocene-Eocene boundary (55 Ma), referred to as the Paleocene-Eocene Thermal Maximum (PETM), was characterized by rapid temperature increase and changes in the global carbon cycle in", "keyphrases": ["productivity", "paleocene-eocene thermal maximum", "petm"]}
{"id": "10.1006/jhev.1999.0359", "title": "Adults only. Reindeer hunting at the middle palaeolithic site salzgitter lebenstedt, northern Germany.", "abstract": "The Middle Palaeolithic site Salzgitter Lebenstedt (northern Germany), excavated in 1952, is well known because of its well-preserved faunal remains, dominated by adult reindeer (Rangifer tarandus). The archaeological assemblage accumulated in an arctic setting in an earlier part of the last (Weichsel) glacial (OIS5-3). The site is remarkable because of the presence of unique Middle Palaeolithic bone tools and the occurrence of the northernmost Neanderthal remains, but this paper focuses on an analysis of its reindeer assemblage. The results indicate autumn hunting of reindeer by Middle Palaeolithic hominids. After the hunt, carcasses were butchered and in subsequent marrow processing of the bones a selection against young and sub-adult animals occurred. Adults were clearly preferred, and from their bones, again, poorer marrow bones were neglected. This focus on primeness of resources has been documented in other domains of Neanderthal behaviour, but Salzgitter Lebenstedt is the best example yet known in terms of systematic and routinized processing of game. The Salzgitter Lebenstedt assemblage displays some remarkable similarities to the Late Glacial reindeer assemblages from the Ahrensburg tunnel valley sites. The subsequent review of the evidence on subsistence strategies from earlier periods of the European Palaeolithic shows that hunting of large mammals may have been a part of the behavioural repertoire of the Middle Pleistocene occupants of Europe from the earliest occupation onwards. At the same time, it is suggested that these early hunting strategies were incorporated in ways of moving through landscapes (\"settlement systems\") which were different from what we know from the middle parts of the Upper Palaeolithic onwards.", "keyphrases": ["reindeer", "northern germany", "occupation", "adult"]}
{"id": "paleo.006087", "title": "Computational biomechanical analyses demonstrate similar shell-crushing abilities in modern and ancient arthropods", "abstract": "The biology of the American horseshoe crab, Limulus polyphemus, is well documented\u2014including its dietary habits, particularly the ability to crush shell with gnathobasic walking appendages\u2014but virtually nothing is known about the feeding biomechanics of this iconic arthropod. Limulus polyphemus is also considered the archetypal functional analogue of various extinct groups with serial gnathobasic appendages, including eurypterids, trilobites and other early arthropods, especially Sidneyia inexpectans from the mid-Cambrian (508 Myr) Burgess Shale of Canada. Exceptionally preserved specimens of S. inexpectans show evidence suggestive of durophagous (shell-crushing) tendencies\u2014including thick gnathobasic spine cuticle and shelly gut contents\u2014but the masticatory capabilities of this fossil species have yet to be compared with modern durophagous arthropods. Here, we use advanced computational techniques, specifically a unique application of 3D finite-element analysis (FEA), to model the feeding mechanics of L. polyphemus and S. inexpectans: the first such analyses of a modern horseshoe crab and a fossil arthropod. Results show that mechanical performance of the feeding appendages in both arthropods is remarkably similar, suggesting that S. inexpectans had similar shell-crushing capabilities to L. polyphemus. This biomechanical solution to processing shelly food therefore has a history extending over 500 Myr, arising soon after the first shell-bearing animals. Arrival of durophagous predators during the early phase of animal evolution undoubtedly fuelled the Cambrian \u2018arms race\u2019 that involved a rapid increase in diversity, disparity and abundance of biomineralized prey species.", "keyphrases": ["arthropod", "horseshoe crab", "finite-element analysis", "fea", "mechanical performance"]}
{"id": "paleo.004120", "title": "Computer Simulations Imply Forelimb-Dominated Underwater Flight in Plesiosaurs", "abstract": "Plesiosaurians are an extinct group of highly derived Mesozoic marine reptiles with a global distribution that spans 135 million years from the Early Jurassic to the Late Cretaceous. During their long evolutionary history they maintained a unique body plan with two pairs of large wing-like flippers, but their locomotion has been a topic of debate for almost 200 years. Key areas of controversy have concerned the most efficient biologically possible limb stroke, e.g. whether it consisted of rowing, underwater flight, or modified underwater flight, and how the four limbs moved in relation to each other: did they move in or out of phase? Previous studies have investigated plesiosaur swimming using a variety of methods, including skeletal analysis, human swimmers, and robotics. We adopt a novel approach using a digital, three-dimensional, articulated, free-swimming plesiosaur in a simulated fluid. We generated a large number of simulations under various joint degrees of freedom to investigate how the locomotory repertoire changes under different parameters. Within the biologically possible range of limb motion, the simulated plesiosaur swims primarily with its forelimbs using an unmodified underwater flight stroke, essentially the same as turtles and penguins. In contrast, the hindlimbs provide relatively weak thrust in all simulations. We conclude that plesiosaurs were forelimb-dominated swimmers that used their hind limbs mainly for maneuverability and stability.", "keyphrases": ["underwater flight", "flipper", "forelimb"]}
{"id": "paleo.001578", "title": "A New Fossil Species of Boa Linnaeus, 1758 (Squamata, Boidae), from the Pleistocene of Marie-Galante Island (French West Indies)", "abstract": "ABSTRACT \n Several studies have reported the occurrence of fossil remains of a now extinct Boa snake from the upper Pleistocene of Marie-Galante Island, French West Indies. However, these remains have never been fully investigated and no complete description of this possible new species has been published. In this paper, we try to bridge this gap by providing a detailed morphological study of the Boa remains discovered in the three major fossil deposits of Marie-Galante Island. Our study reveals the specific morphological aspects of this fossil snake and allows us to identify it as a new species, Boa blanchardensis. We also reconstructed its body size, carried out a paleohistological investigation, and suggest that this snake may have been a dwarf species. We then discuss the possible explanation for the extinction of this snake on Marie-Galante Island and possibly also on other Guadeloupe islands.", "keyphrases": ["pleistocene", "marie-galante island", "fossil snake"]}
{"id": "paleo.009653", "title": "When Did Carcharocles megalodon Become Extinct? A New Analysis of the Fossil Record", "abstract": "Carcharocles megalodon (\u201cMegalodon\u201d) is the largest shark that ever lived. Based on its distribution, dental morphology, and associated fauna, it has been suggested that this species was a cosmopolitan apex predator that fed on marine mammals from the middle Miocene to the Pliocene (15.9\u20132.6 Ma). Prevailing theory suggests that the extinction of apex predators affects ecosystem dynamics. Accordingly, knowing the time of extinction of C. megalodon is a fundamental step towards understanding the effects of such an event in ancient communities. However, the time of extinction of this important species has never been quantitatively assessed. Here, we synthesize the most recent records of C. megalodon from the literature and scientific collections and infer the date of its extinction by making a novel use of the Optimal Linear Estimation (OLE) model. Our results suggest that C. megalodon went extinct around 2.6 Ma. Furthermore, when contrasting our results with known ecological and macroevolutionary trends in marine mammals, it became evident that the modern composition and function of modern gigantic filter-feeding whales was established after the extinction of C. megalodon. Consequently, the study of the time of extinction of C. megalodon provides the basis to improve our understanding of the responses of marine species to the removal of apex predators, presenting a deep-time perspective for the conservation of modern ecosystems.", "keyphrases": ["shark", "pliocene", "early paleocene", "apex predatory selachian"]}
{"id": "paleo.007811", "title": "Commensal anomiid bivalves on Late Cretaceous heteromorph ammonites from south\u2010west Japan", "abstract": "The heteromorph ammonite Pravitoceras sigmoidale from the Upper Cretaceous Seidan Formation (Izumi Group) in south\u2010west Japan is frequently encrusted by sessile anomiid bivalves. Fossils of P. sigmoidale with anomiids are often concentrated at the top of or just above turbidite sandstones. Projecting retroversal hooks and apertures of P. sigmoidale are usually intact, and some individuals are associated with jaw apparatuses near apertures. Anomiids are found on both sides and ventral peripheries of P. sigmoidale conchs, attached predominantly to body chambers. These modes of occurrence suggest that the encrustation by anomiids occurred not on post\u2010mortem floating or sunken carcasses but on live conchs and that these organisms were rapidly buried by turbidity current deposits shortly after death. Attachment to both flanks and ventral peripheries of the retroversal hooks may indicate that at least adult individuals of P. sigmoidale did not lie on the sea floor and did not drag their body chambers. It is suggested that fully mature individuals of this ammonite species lived for a long period of time after having formed the retroversal hook because a few generations of anomiids have colonized a single body chamber. Such colonization by anomiids is also observed on Didymoceras awajiense, which is considered to be the closely related ancestral species of P. sigmoidale. This anomiid\u2013heteromorph ammonite commensal relationship might continue to persist in descendants during the course of evolution of these heteromorph ammonites.", "keyphrases": ["anomiid bivalve", "heteromorph", "south\u2010w japan"]}
{"id": "10.1029/2011gl048280", "title": "The role of ocean thermal expansion in Last Interglacial sea level rise", "abstract": "A compilation of paleoceanographic data and a coupled atmosphere\u2010ocean climate model were used to examine global ocean surface temperatures of the Last Interglacial (LIG) period, and to produce the first quantitative estimate of the role that ocean thermal expansion likely played in driving sea level rise above present day during the LIG. Our analysis of the paleoclimatic data suggests a peak LIG global sea surface temperature (SST) warming of 0.7 \u00b1 0.6\u00b0C compared to the late Holocene. Our LIG climate model simulation suggests a slight cooling of global average SST relative to preindustrial conditions (\u0394SST = \u22120.4\u00b0C), with a reduction in atmospheric water vapor in the Southern Hemisphere driven by a northward shift of the Intertropical Convergence Zone, and substantially reduced seasonality in the Southern Hemisphere. Taken together, the model and paleoceanographic data imply a minimal contribution of ocean thermal expansion to LIG sea level rise above present day. Uncertainty remains, but it seems unlikely that thermosteric sea level rise exceeded 0.4 \u00b1 0.3 m during the LIG. This constraint, along with estimates of the sea level contributions from the Greenland Ice Sheet, glaciers and ice caps, implies that 4.1 to 5.8 m of sea level rise during the Last Interglacial period was derived from the Antarctic Ice Sheet. These results reemphasize the concern that both the Antarctic and Greenland Ice Sheets may be more sensitive to temperature than widely thought.", "keyphrases": ["ocean", "thermal expansion", "sst"]}
{"id": "paleo.007829", "title": "The Palaeozoic colonization of the water column and the rise of global nekton", "abstract": "The colonization of the water column is among the most important transformations in the evolution of animal life and global ecosystems. The Devonian nekton revolution has been identified as a major macroevolutionary event signifying the rapid occupation of the water column by independent radiations of swimming animals. Using new data, an expanded taxonomic coverage, sample standardization and increased ecological resolution, we analysed patterns of nektonization during the Palaeozoic. We find that nekton and eunekton were well established prior to the Devonian and did not diversify dramatically during any Palaeozoic interval. Relative nektic diversity and occurrences decreased rather than increased during the Devonian. Eunektic diversity and occurrences increased throughout the Palaeozoic, but this rise was protracted and cannot be attributed to any single interval. Our new data indicate that the metazoan colonization of the water column was considerably more complex and gradual than previously understood.", "keyphrases": ["water column", "nekton", "devonian nekton revolution"]}
{"id": "paleo.007601", "title": "Revision and re-description of Micropeltis isseli Airaghi, 1901 (Echinodermata: Echinoidea)", "abstract": "Re-discovery of the holotype of ''Micropeltis '' isseli Airaghi, 1901, in the collection of the Museo di Paleontologia (University of Genova), allowed for a reassessment of its morphological features and revision of its systematic placement. The discovery of ambulacral plate compounding that is compatible with that of phymosomatids, in combination with its pore arrangement and tuberculation pattern, indicates that this species should be transferred to the genus Phymotaxis. Comparison with museum collections from the type area allowed for clarification of the type-locality and stratum. The specimen most likely derives from the Tortonian Marne di S. Agata Fossili beds exposed at Bocca d'Asino, northeast of Stazzano, which is in line with Airaghi's statement in the original description (in contrast to the original plate caption). This indicates that Phymotaxis isseli is the youngest representative of the echinoid order phymosomatida known to date, extending its range to the Late Miocene.", "keyphrases": ["micropeltis", "isseli airaghi", "revision"]}
{"id": "paleo.008078", "title": "Small Theropod Teeth from the Late Cretaceous of the San Juan Basin, Northwestern New Mexico and Their Implications for Understanding Latest Cretaceous Dinosaur Evolution", "abstract": "Studying the evolution and biogeographic distribution of dinosaurs during the latest Cretaceous is critical for better understanding the end-Cretaceous extinction event that killed off all non-avian dinosaurs. Western North America contains among the best records of Late Cretaceous terrestrial vertebrates in the world, but is biased against small-bodied dinosaurs. Isolated teeth are the primary evidence for understanding the diversity and evolution of small-bodied theropod dinosaurs during the Late Cretaceous, but few such specimens have been well documented from outside of the northern Rockies, making it difficult to assess Late Cretaceous dinosaur diversity and biogeographic patterns. We describe small theropod teeth from the San Juan Basin of northwestern New Mexico. These specimens were collected from strata spanning Santonian \u2013 Maastrichtian. We grouped isolated theropod teeth into several morphotypes, which we assigned to higher-level theropod clades based on possession of phylogenetic synapomorphies. We then used principal components analysis and discriminant function analyses to gauge whether the San Juan Basin teeth overlap with, or are quantitatively distinct from, similar tooth morphotypes from other geographic areas. The San Juan Basin contains a diverse record of small theropods. Late Campanian assemblages differ from approximately co-eval assemblages of the northern Rockies in being less diverse with only rare representatives of troodontids and a Dromaeosaurus-like taxon. We also provide evidence that erect and recurved morphs of a Richardoestesia-like taxon represent a single heterodont species. A late Maastrichtian assemblage is dominated by a distinct troodontid. The differences between northern and southern faunas based on isolated theropod teeth provide evidence for provinciality in the late Campanian and the late Maastrichtian of North America. However, there is no indication that major components of small-bodied theropod diversity were lost during the Maastrichtian in New Mexico. The same pattern seen in northern faunas, which may provide evidence for an abrupt dinosaur extinction.", "keyphrases": ["late cretaceous", "northwestern new mexico", "theropod tooth"]}
{"id": "10.1126/science.1200803", "title": "The Magnitude and Duration of Late Ordovician\u2013Early Silurian Glaciation", "abstract": "Carbonate isotopes reveal a link between past ocean temperatures and mass extinction. Understanding ancient climate changes is hampered by the inability to disentangle trends in ocean temperature from trends in continental ice volume. We used carbonate \u201cclumped\u201d isotope paleothermometry to constrain ocean temperatures, and thereby estimate ice volumes, through the Late Ordovician\u2013Early Silurian glaciation. We find tropical ocean temperatures of 32\u00b0 to 37\u00b0C except for short-lived cooling by ~5\u00b0C during the final Ordovician stage. Evidence for ice sheets spans much of the study interval, but the cooling pulse coincided with a glacial maximum during which ice volumes likely equaled or exceeded those of the last (Pleistocene) glacial maximum. This cooling also coincided with a large perturbation of the carbon cycle and the Late Ordovician mass extinction.", "keyphrases": ["silurian glaciation", "cooling", "ice sheet"]}
{"id": "paleo.010404", "title": "Phylogeography of the second plague pandemic revealed through analysis of historical Yersinia pestis genomes", "abstract": "The second plague pandemic, caused by Yersinia pestis, devastated Europe and the nearby regions between the 14th and 18th centuries AD. Here we analyse human remains from ten European archaeological sites spanning this period and reconstruct 34 ancient Y. pestis genomes. Our data support an initial entry of the bacterium through eastern Europe, the absence of genetic diversity during the Black Death, and low within-outbreak diversity thereafter. Analysis of post-Black Death genomes shows the diversification of a Y. pestis lineage into multiple genetically distinct clades that may have given rise to more than one disease reservoir in, or close to, Europe. In addition, we show the loss of a genomic region that includes virulence-related genes in strains associated with late stages of the pandemic. The deletion was also identified in genomes connected with the first plague pandemic (541\u2013750 AD), suggesting a comparable evolutionary trajectory of Y. pestis during both events.", "keyphrases": ["second plague pandemic", "yersinia pestis", "genome"]}
{"id": "10.1002/evan.21854", "title": "Issues of theory and method in the analysis of Paleolithic mortuary behavior: A view from Shanidar Cave", "abstract": "Mortuary behavior (activities concerning dead conspecifics) is one of many traits that were previously widely considered to have been uniquely human, but on which perspectives have changed markedly in recent years. Theoretical approaches to hominin mortuary activity and its evolution have undergone major revision, and advances in diverse archeological and paleoanthropological methods have brought new ways of identifying behaviors such as intentional burial. Despite these advances, debates concerning the nature of hominin mortuary activity, particularly among the Neanderthals, rely heavily on the rereading of old excavations as new finds are relatively rare, limiting the extent to which such debates can benefit from advances in the field. The recent discovery of in situ articulated Neanderthal remains at Shanidar Cave offers a rare opportunity to take full advantage of these methodological and theoretical developments to understand Neanderthal mortuary activity, making a review of these advances relevant and timely.", "keyphrases": ["mortuary behavior", "shanidar cave", "neanderthals", "excavation"]}
{"id": "10.2475/09.2009.01", "title": "Quantitative uncertainty analyses of ancient atmospheric CO2 estimates from fossil leaves", "abstract": "The relationship between atmospheric CO2 and ancient climate is of fundamental importance for gauging the climate sensitivity of the Earth system to a changing CO2 regime. One of the most widely adopted paleobiological CO2 proxies for reconstructing Earth's atmospheric CO2 history exploits the inverse relationship between leaf stomatal index, the fraction of leaf epidermal cells that are stomatal structures, and atmospheric CO2. However, fossil leaf-based CO2 reconstructions make a priori assumptions about the form of the empirical relationship between SI and CO2 required for transfer functions and have failed to correctly propagate error terms. These effects can translate into erroneous interpretations that undermine the value of the proxy. Here we report the development and application of a rigorous generalized statistical framework overcoming these limitations that generates probability density functions for each atmospheric CO2 estimate. The utility of our statistical tools is demonstrated by showing how they revise earlier atmospheric CO2 estimates from fossil cuticles of Ginkgo and Metasequoia trees during the early Eocene and middle Miocene warm periods upwards by +150 to 250 ppm to 450 to 700 ppm. The revised CO2 reconstructions therefore help to resolve the paradox of warm Paleogene and Neogene \u201cgreenhouse\u201d climates co-existing with near present-day levels of CO2 and support the emerging view from independent paleoclimate studies for a high climate sensitivity of the Earth system. The statistical tools presented are sufficiently versatile to permit their use in other investigations of paleoCO2 estimates from fossil leaves.", "keyphrases": ["atmospheric co2 estimate", "fossil leave", "middle miocene", "ppm"]}
{"id": "10.1017/S0016756809006451", "title": "Carbon isotope stratigraphy across the Silurian\u2013Devonian transition in Podolia, Ukraine: evidence for a global biogeochemical perturbation", "abstract": "Abstract The carbon and oxygen isotope composition of marine carbonates (\u03b413C and \u03b418O, respectively) are studied in the fossiliferous, stratigraphically well-constrained and remarkably expanded successions of Podolia, SW Ukraine, spanning the Silurian\u2013Devonian transition. Significant isotopic shifts are directly comparable to previously published global secular trends in well-preserved brachiopod calcite isotopic ratios from this region, and therefore may be taken as a reliable primary record of seawater \u03b413C changes. The sections reveal a major positive \u03b413C excursion, with an amplitude above 6 \u2030, beginning in the upper Pridoli and reaching peak values as heavy as +4.2 \u2030 in the lowermost Lochkovian. This turnover in carbon cycling is followed by a general trend toward more negative \u03b413C values in the upper Lochkovian. The Podolian isotopic signals provide strong support for the previously inferred global biogeochemical perturbation across the Silurian\u2013Devonian transition, reflecting a complex combination of palaeogeographical, biogeochemical and evolutionary processes in the late Caledonian geodynamic setting, with a likely undervalued role of the expanding vegetation in vast near-coastal shallows and deltas.", "keyphrases": ["silurian\u2013devonian transition", "global biogeochemical perturbation", "succession"]}
{"id": "paleo.006851", "title": "What big eyes you have: the ecological role of giant pterygotid eurypterids", "abstract": "Eurypterids are a group of extinct chelicerates that ranged for over 200 Myr from the Ordovician to the Permian. Gigantism is common in the group; about 50% of families include taxa over 0.8 m in length. Among these were the pterygotids (Pterygotidae), which reached lengths of over 2 m and were the largest arthropods that ever lived. They have been interpreted as highly mobile visual predators on the basis of their large size, enlarged, robust chelicerae and forward-facing compound eyes. Here, we test this interpretation by reconstructing the visual capability of Acutiramus cummingsi (Pterygotidae) and comparing it with that of the smaller Eurypterus sp. (Eurypteridae), which lacked enlarged chelicerae, and other arthropods of similar geologic age. In A. cummingsi, there is no area of lenses differentiated to provide increased visual acuity, and the interommatidial angles (IOA) do not fall within the range of high-level modern arthropod predators. Our results show that the visual acuity of A. cummingsi is poor compared with that of co-occurring Eurypterus sp. The ecological role of pterygotids may have been as predators on thin-shelled and soft-bodied prey, perhaps in low-light conditions or at night.", "keyphrases": ["ecological role", "chelicerae", "lense", "acuity", "ioa"]}
{"id": "paleo.012170", "title": "Calibrated Tree Priors for Relaxed Phylogenetics and Divergence Time Estimation", "abstract": "Abstract The use of fossil evidence to calibrate divergence time estimation has a long history. More recently, Bayesian Markov chain Monte Carlo has become the dominant method of divergence time estimation, and fossil evidence has been reinterpreted as the specification of prior distributions on the divergence times of calibration nodes. These so-called \u201csoft calibrations\u201d have become widely used but the statistical properties of calibrated tree priors in a Bayesian setting hashave not been carefully investigated. Here, we clarify that calibration densities, such as those defined in BEAST 1.5, do not represent the marginal prior distribution of the calibration node. We illustrate this with a number of analytical results on small trees. We also describe an alternative construction for a calibrated Yule prior on trees that allows direct specification of the marginal prior distribution of the calibrated divergence time, with or without the restriction of monophyly. This method requires the computation of the Yule prior conditional on the height of the divergence being calibrated. Unfortunately, a practical solution for multiple calibrations remains elusive. Our results suggest that direct estimation of the prior induced by specifying multiple calibration densities should be a prerequisite of any divergence time dating analysis.", "keyphrases": ["divergence time estimation", "calibration", "choice"]}
{"id": "10.2973/odp.proc.sr.183.015.2003", "title": "Leg 183 synthesis: Kerguelen plateau-broken ridge-a large igneous province", "abstract": "The Kerguelen Plateau and Broken Ridge form a large igneous \nprovince (LIP) in the southern Indian Ocean. The main objectives of \nOcean Drilling Program Leg 183 were to understand the origin and evolution \nof this LIP and the impact of its formation on the environment. \nIgneous basement (33 to 233 m of penetration) has been recovered \nfrom 11 drill sites on the LIP, and 7 are Leg 183 sites. Studies of the basement \nand sediment cores lead to the following conclusions. \n1. Formation of the LIP postdated breakup between India and Antarctica, \nwith eruption ages (40Ar/39Ar) ranging from ~119 Ma in the southern Kerguelen Plateau (SKP) to ~34 Ma in the northern Kerguelen Plateau. Apparently, peaks in magmatic output (~0.9 km3/yr) occurred in the intervals of 119\u2013110 and 105\u201395 Ma. \nAlthough an important caveat is that we have access only to \nuppermost basement of a thick (~20 km) igneous crust, these \nresults are inconsistent with massive volcanism associated with \na single plume head and continental breakup. \n2. The uppermost igneous basement is dominantly tholeiitic \nbasalt. Based on the physical characteristics of the lava flows, \nwhich indicate subaerial eruption, and the occurrence of overlying \nterrestrially derived sediments containing wood fragments, \nfern remains, and terrestrial palynoflora, much of the LIP was \nabove sea level when magmatic output was high. \n3. The geochemical characteristics of basalt forming the LIP are unlike mid-ocean-ridge basalt (MORB). There are, however significant geochemical differences between tholeiitic basalt \nerupted at each site. These differences are attributed to varying \nproportions of components derived from the Kerguelen plume, \ndepleted MORB-related asthenosphere, and continental lithosphere. \n4. Based on radiogenic isotopic ratios and incompatible element \nabundances, tholeiitic basalt of Cretaceous age from spatially \ndiverse locations (Site 738 in the SKP, Site 1137 on Elan Bank, \nSite 747 in the Central Kerguelen Plateau (CKP), and Site 1142 \non Broken Ridge) contains up to ~5% of a component derived \nfrom continental crust. The Proterozoic-age zircon and monazite \nin clasts of garnet-biotite gneiss in a conglomerate intercalated \nwith basalt at Site 1137 demonstrate that continental crust fragments \nare present in the Indian Ocean lithosphere. \n5. Surprising new results for oceanic LIPs are the dominance of \nalkalic lavas, trachybasalt to trachyte and rhyolite, at Skiff Bank \nand the pyroclastic deposits present on Skiff Bank, Elan Bank, \nand the CKP. Explosive subaerial volcanism at high latitudes can \ncontribute volatiles to the stratosphere; therefore, LIP volcanism \nmay have had a significant environmental impact. \n6. Flora and fauna preserved in Kerguelen Plateau sediments \nprovide a long-term record of the plateau\u2019s environment, beginning \nwith terrestrial and shallow-marine deposition followed by \nequable Cretaceous paleoceanographic conditions, the abrupt \nCretaceous/Tertiary boundary, the Late Paleocene Thermal \nMaximum, and cooling of the Southern Ocean through Tertiary \ntime.", "keyphrases": ["province", "oceanic lip", "leg"]}
{"id": "10.1080/00379271.2010.10697669", "title": "The Wagner Parsimony using morphological characters: a new method for palaeosynecological studies", "abstract": "Abstract The limits and difficulties related to the tools currently in use for palaeosynecological comparisons of faunas or floras of different geological periods are discussed. The new method of the Wagner parsimony Applied to Palaeosynecology Using Morphology (WAPUM method), is defined and tested on morphological characters gathered from two insect groups Odonatoptera and Thripida. The difficulties related to the monophyly of the taxonomic groups used in the more traditional approaches are no longer a problem when using the WAPUM method. In the WAPUM a character is \u2018presence versus absence of species bearing a morphological structure\u2019. The results obtained from use of the WAPUM minimize the number of changes among character states. Application of the WAPUM could reveal signals to confirm or object the currently available scenarios for the global changes in the evolution of past diversity and disparity of organisms (major changes or global crises of diversity).", "keyphrases": ["wagner parsimony", "palaeosynecology", "geological period", "thripida"]}
{"id": "10.1098/rsos.200305", "title": "Dietary palaeoecology of an Early Cretaceous armoured dinosaur (Ornithischia; Nodosauridae) based on floral analysis of stomach contents", "abstract": "The exceptionally well-preserved holotype of the armoured dinosaur Borealopelta markmitchelli (Ornithischia; Nodosauridae) from the Early Cretaceous (Clearwater Formation) of northern Alberta preserves a distinct mass within the abdominal cavity. Fourteen independent criteria (including: co-allochthony, anatomical position, gastroliths) support the interpretation of this mass as ingested stomach contents\u2014a cololite. Palynomorphs in the cololite are a subset of the more diverse external sample. Analysis of the cololite documents well-preserved plant material dominated by leaf tissue (88%), including intact sporangia, leaf cross-sections and cuticle, but also including stems, wood and charcoal. The leaf fraction is dominated (85%) by leptosporangiate ferns (subclass Polypodiidae), with low cycad\u2013cycadophyte (3%) and trace conifer foliage. These data represent the most well-supported and detailed direct evidence of diet in an herbivorous dinosaur. Details of the dietary palaeoecology of this nodosaur are revealed, including: selective feeding on ferns; preferential ingestion of leptosporangiate ferns to the exclusion of Osmundaceae and eusporangiate ferns such as Marattiaceae; and incidental consumption of cycad\u2013cycadophyte and conifer leaves. The presence of significant (6%) charcoal may represent the dietary use of recently burned conifer forest undergoing fern succession, early evidence of a fire succession ecology, as is associated with many modern large herbivores.", "keyphrases": ["nodosauridae", "stomach content", "plant material", "herbivorous dinosaur", "dietary palaeoecology"]}
{"id": "paleo.008905", "title": "Revision of the Early Devonian psammosteids from the \u201cPlacoderm Sandstone\u201d: Implications for their body shape reconstruction", "abstract": "The Early Devonian psammosteid agnathans (Guerichosteus and Hariosteus) originally described by Tarlo (1964, 1965) from the so-called \u201cPlacoderm Sandstone\u201d are revised. The newly collected material from the Holy Cross Mountains allows detailed reexamination and provides new anatomical information. The morphology and ornamentation of the plates supports the establishment of the genera Guerichosteus and Hariosteus. However, G. kotanskii, G. kulczyckii and G. lefeldi should be considered as junior synonyms of Guerichosteus kozlowskii. Hariosteus lobanowskii, erected by Tarlo (1964), is considered here as invalid (nomen dubium) and H. kotanskii is included with Hariosteus kielanae. The three-dimensional scanning of plates belonging to Guerichosteus allows for a more detailed description and reconstruction. In cross section the deep ventral part of the trunk is V-shaped in contrast to previous U-shaped restorations. Probably, the Early Devonian psammosteid, Drepanaspis gemuendenesis in particular, shared this body shape. Marek Dec. Institute of Palaeobiology, Polish Academy of Sciences, Twarda 51/55, 00-818 Warszawa, Poland. mdec@wp.pl", "keyphrases": ["psammosteids", "placoderm sandstone", "body shape", "guerichosteus kozlowskii"]}
{"id": "paleo.010550", "title": "The Great American Biotic Interchange revisited: a new perspective from the stable isotope record of Argentine Pampas fossil mammals", "abstract": "This study aims at assessing resource and habitat use, niche occupation and trophic interactions from a stable isotope perspective on fossil mammals from the Argentine Pampas during the Great American Biotic Interchange (GABI). We present stable isotope data of more than 400 samples belonging to 10 mammalian orders and spanning a temporal range from ~9.5 Ma to ~12 ky. Rodents, notoungulates and pilosians record an increase in the consumption of C4 plants, whereas litopterns and cingulates show \u03b413C values that remain mostly within a C3-dominated diet. Our stable isotope data indicates that the expansion of C4 vegetation opened up new niche opportunities, probably alleviating resource competition among endemic taxa. Gomphothere, equid and camelid \u03b413C records show a broad variability pointing to consumption of C3 and mixed C3-C4 vegetation. This flexible dietary behavior may have facilitated the successful settlement of immigrant groups in South America. In the case of carnivorous taxa, Late Miocene pre-GABI endemic sparassodonts consumed prey from C3 environments, whereas immigrant carnivorans preferred prey from mixed C3-C4 areas. Our research contributes to the study of the GABI from a different perspective as stable isotope records permit to characterize, from a (semi)quantitative standpoint, ecological traits within extinct fauna.", "keyphrases": ["american biotic interchange", "stable isotope record", "south america", "new discovery"]}
{"id": "paleo.005946", "title": "The dawn of a dynasty : life strategies of Cambrian and Ordovician brachiopods.", "abstract": "Brachiopods are among the first animal phyla to emerge from the Cambrian Explosion, rapidly diversifying to all major palaeocontinental blocks within 20 million years. The group underwent another steep rise in diversity during the Ordovician, and their relative abundance and diversity made them one of the most successful invertebrate groups during the entire Palaeozoic. During this time, brachiopods lived in a range of environments and represented a significant component of marine ecosystems, yet information regarding their modes of life and ecology is somewhat limited. Recent studies, primarily from the Chengjiang and Burgess Shale Lagerstatten, have revealed that by the Middle Cambrian (Series 3, Stage 5) brachiopods from across the phylum had already developed a range of ecological strategies and life modes. Cambrian brachiopods occupied distinct trophic niches on soft and hard substrates and exhibited at least five types of lifestyles: pedicle attachment, pedicle anchoring, cemented, free\u2010lying and semi\u2010infaunal. Comparisons with Ordovician benthic assemblages show that despite the explosion of brachiopod taxa witnessed in the Ordovician, with the exception of the appearance of burrowing brachiopods, life strategies of brachiopods remained largely the same. Indicating that the majority of life modes observed in brachiopods had rapidly evolved and was already in place prior to the Great Ordovician Biodiversity Event.", "keyphrases": ["life strategy", "ordovician", "brachiopod", "palaeozoic"]}
{"id": "paleo.010619", "title": "Evolution, Systematics, and Phylogeography of Pleistocene Horses in the New World: A Molecular Perspective", "abstract": "The rich fossil record of horses has made them a classic example of evolutionary processes. However, while the overall picture of equid evolution is well known, the details are surprisingly poorly understood, especially for the later Pliocene and Pleistocene, c. 3 million to 0.01 million years (Ma) ago, and nowhere more so than in the Americas. There is no consensus on the number of equid species or even the number of lineages that existed in these continents. Likewise, the origin of the endemic South American genus Hippidion is unresolved, as is the phylogenetic position of the \u201cstilt-legged\u201d horses of North America. Using ancient DNA sequences, we show that, in contrast to current models based on morphology and a recent genetic study, Hippidion was phylogenetically close to the caballine (true) horses, with origins considerably more recent than the currently accepted date of c. 10 Ma. Furthermore, we show that stilt-legged horses, commonly regarded as Old World migrants related to the hemionid asses of Asia, were in fact an endemic North American lineage. Finally, our data suggest that there were fewer horse species in late Pleistocene North America than have been named on morphological grounds. Both caballine and stilt-legged lineages may each have comprised a single, wide-ranging species.", "keyphrases": ["horse", "north america", "genetic study", "stilt-legged horse", "mitochondrial dna"]}
{"id": "10.1080/02724634.1997.10011021", "title": "The osteology and paleoecology of the giant otter Enhydritherium terraenovae", "abstract": "ABSTRACT The giant otter Enhydritherium terraenovae, a New World taxon thought to be related to both the Old World otter Enhydriodon and the extant sea otter Enhydra, was originally described on the basis of relatively limited material, mostly dental. However, an incomplete skeleton of E. terraenovae recovered from the early Hemphillian Moss Acres Racetrack site in northern Florida includes a skull, mandible, part of the axial skeleton, and most of both the fore- and hindlimbs, adding greatly to knowledge of this animal. On the basis of this new material, the osteology of this species is described in detail for the first time, with its diagnosis revised accordingly. This new osteological information, along with information about the nature of the Moss Acres Racetrack site, allows such paleoecological and functional aspects of E. terraenovae as habitat preference, mode of swimming, and diet to be inferred or interpreted in a detail previously impossible. E. terraenovae: 1) was a habitat generalist rather t...", "keyphrases": ["osteology", "otter enhydritherium terraenovae", "florida"]}
{"id": "paleo.007804", "title": "EOCENE RECORDS OF BEE FLIES (INSECTA, DIPTERA, BOMBYLIIDAE, COMPTOSIA): THEIR PALAEOBIOGEOGRAPHIC IMPLICATIONS AND REMARKS ON THE EVOLUTIONARY HISTORY OF BOMBYLIIDS", "abstract": "Abstract:\u2002 The first fossil records of Holarctic representatives of the genus Comptosia Macquart, 1840 from the middle Eocene Messel Pit, Germany, and the upper Eocene of Florissant, USA, are reported. The fossil from Messel, Comptosia pria sp. nov., is represented by a well\u2010preserved wing, displaying characteristic wing venation, remains of the second wing and elements of the thorax. The Florissant fossil, C. miranda comb. nov., is preserved almost completely with both wings and most parts of the body visible. Extant members of the genus Comptosia are currently found only in Australia, and close relatives are known from southern South America. Previously this group of genera has been thought to be of Gondwanan origin, but these Eocene fossil representatives of Comptosia from the Holarctic region argue against this interpretation, and suggest that Comptosia and its relatives were more widespread in both Northern and Southern hemispheres during the Palaeogene. The fossil record of bee flies suggests a major radiation of bombyliids in the late Cretaceous or early Cenozoic. This assumption is supported by the comparatively young geological age of many bombyliid host taxa. A key factor driving the specialization of many bombyliid larvae on ground\u2010dwelling hosts may have been avoidance of competition with tachinid flies and parasitic hymenopterans.", "keyphrases": ["bee fly", "bombyliid", "eocene"]}
{"id": "paleo.004747", "title": "A \u2018Terror of Tyrannosaurs\u2019: The First Trackways of Tyrannosaurids and Evidence of Gregariousness and Pathology in Tyrannosauridae", "abstract": "The skeletal record of tyrannosaurids is well-documented, whereas their footprint record is surprisingly sparse. There are only a few isolated footprints attributed to tyrannosaurids and, hitherto, no reported trackways. We report the world\u2019s first trackways attributable to tyrannosaurids, and describe a new ichnotaxon attributable to tyrannosaurids. These trackways are from the Upper Cretaceous (Campanian - Maastrichtian) of northeastern British Columbia, Canada. One trackway consists of three tridactyl footprints, and two adjacent trackways consist of two footprints each. All three trackways show animals bearing southeast within an 8.5 meter-wide corridor. Similarities in depth and preservation of the tyrannosaurid tracks indicate that these three trackways were made by track-makers walking concurrently in the same direction. These trackways add significantly to previous osteology-based hypotheses of locomotion and behavior in Tyrannosauridae by providing ichnologic support for gregariousness in tyrannosaurids, and the first record of the walking gait of tyrannosaurids.", "keyphrases": ["gregariousness", "tyrannosauridae", "footprint", "british columbia"]}
{"id": "paleo.004346", "title": "Chaetopterid Tubes from Vent and Seep Sites: Implications for Fossil Record and Evolutionary History of Vent and Seep Annelids", "abstract": "Vestimentiferan tube worms living at deep-sea hydrothermal vents and cold seeps have been considered as a clade with a long and continuing evolutionary history in these ecosystems. Whereas the fossil record appears to support this view, molecular age estimates do not. The two main features that are used to identify vestimentiferan tubes in the fossil record are longitudinal ridges on the tube's surface and a tube wall constructed of multiple layers. It is shown here that chaetopterid tubes from modern vents and seeps\u2014as well as a number of fossil tubes from shallow-water environments\u2014also show these two features. This calls for a more cautious interpretation of tubular fossils from ancient vent and seep deposits. We suggest that: current estimates for a relatively young evolutionary age based on molecular clock methods may be more reliable than the inferences of ancient \u201cvestimentiferans\u201d based on putative fossils of these worms; not all of these putative fossils actually belong to this group; and that tubes from fossil seeps should be investigated for chitinous remains to substantiate claims of their potential siboglinid affinities.", "keyphrases": ["vent", "evolutionary history", "vestimentiferan"]}
{"id": "paleo.003885", "title": "Redescription and palaeobiology of Palaeoscorpius devonicus Lehmann, 1944 from the Lower Devonian Hunsr\u00fcck Slate of Germany", "abstract": "Abstract:\u2002 Palaeoscorpius devonicus Lehmann, 1944 is known from only a single specimen, found in the Eschenbach Pit near Bundenbach in the Lower Devonian Hunsr\u00fcck Slate of Germany. It is a key fossil, having been interpreted both as the most basal member of the Scorpiones and as one of the order\u2019s most likely candidates for an aquatic mode of life. Prepared both ventrally and dorsally, some aspects of its morphology remain problematic. Here, with the aid of new techniques, including computed tomography, we present a re\u2010investigation of this scorpion\u2019s anatomy and a new reconstruction, with a particular focus on the species\u2019 original habitat. On the basis of the environmental interpretation of the Hunsr\u00fcck Slate and the completeness of the specimen, previous authors concluded that P. devonicus was marine, but none offered convincing morphological evidence. Recent studies of the deposit\u2019s environment suggest that the Hunsr\u00fcck Sea was part of an intrashelf basin, relatively close to the coastline, and fossils of land plants show that terrestrial wash\u2010in occasionally occurred. Our revised interpretation of the fossil\u2019s morphology demonstrates that the scorpion was most probably terrestrial. Internal mesosomal organs are interpreted as book lungs, but other terrestrial adaptations are lacking. The absence of both coxapophyses and gnathobases makes determining the scorpion\u2019s feeding mechanism difficult. Interpreting the scorpion\u2019s character states within a phylogenetic framework, especially the possible presence of book lungs, implies either that the plesiomorphic position of P. devonicus is no longer supported or that the development of book lungs had already taken place early in the scorpion lineage.", "keyphrases": ["palaeoscorpius devonicus lehmann", "germany", "scorpion", "possible presence"]}
{"id": "10.5710/PEAPA.15.06.2015.103", "title": "THE ALLIGATOROIDEA OF ARGENTINA: AN UPDATE OF ITS FOSSIL RECORD", "abstract": "The fossil record of Alligatoroidea in Argentina is mainly represented by Caimaninae alligatorids. This lineage recorded two impor- tant moments in its natural history, one at the beginning of the Paleogene (Late Paleocene\u2013Middle Eocene) and the other in the Neogene (Late Miocene). The most ancient record of alligatoroids in South America comes from the Early Paleocene of Patagonia. It includes basal forms of caimanines such as Necrosuchus ionensis, Eocaiman palaeocenicus, Eocaiman cavernensis, and probably a new species of alligatoroid, which provide key morphological information on the evolutionary and biogeographic history of these crocodylians. Another important moment of the evolutionary history of caimanines is the diversification of the lineage observed during the Miocene. Although there is some isolated cranial material of caimanines from the Late Miocene of northwestern Argentina, the most abundant and diverse fossil Miocene material comes from the northeast, from a level informally called \u201cConglomerado Osifero\u201d. Two genera of caimanines are known from this stratigraphic level (Caiman and Mourasuchus) with at least five valid species. Here we present an update of the knowledge of Cenozoic alligatorids of Argentina, as a tribute to Zulma Gasparini for her invaluable contribution to the understanding of the crocodilian evolution in South America.", "keyphrases": ["alligatoroidea", "argentina", "update", "miocene", "south america"]}
{"id": "10.1371/journal.pone.0206483", "title": "Fine Endmesolithic fish caviar meal discovered by proteomics in foodcrusts from archaeological site Friesack 4 (Brandenburg, Germany)", "abstract": "The role of aquatic resources in ancient economies and paleodiet is important for understanding the evolution of prehistorical societies. Charred food remains from ancient pottery are valuable molecular evidence of dietary habits in antiquity. However, conventional archaeometric approaches applied in their analysis lack organismal specificity, are affected by abundant environmental contaminants, do not elucidate food processing recipes and are limited in the inland regions where diverse dietary resources are available. We performed proteomics analysis of charred organic deposits adhered on early ceramics from Mesolithic-Neolithic inland site Friesack 4 (Brandenburg, Germany). One of pots\u2014a small coarse bowl radiocarbon dated to the end of the 5th millennium BC\u2014was attributed to Endmesolithic pottery. Proteomics of foodcrust from this vessel identified fine carp roe meal and revealed details of a prehistorical culinary recipe. Ancient proteins were unequivocally distinguished from contemporary contaminants by computing deamidation ratios of glutamine residues. These data paint a broader picture of the site-specific exploitation of aquatic resources and contribute to better understanding of the dietary context of Neolithic transition in European inland.", "keyphrases": ["proteomic", "foodcrust", "germany"]}
{"id": "paleo.001474", "title": "Intra-Trackway Morphological Variations Due to Substrate Consistency: The El Frontal Dinosaur Tracksite (Lower Cretaceous, Spain)", "abstract": "An ichnological and sedimentological study of the El Frontal dinosaur tracksite (Early Cretaceous, Cameros basin, Soria, Spain) highlights the pronounced intra-trackway variation found in track morphologies of four theropod trackways. Photogrammetric 3D digital models revealed various and distinct intra-trackway morphotypes, which reflect changes in footprint parameters such as the pace length, the track length, depth, and height of displacement rims. Sedimentological analyses suggest that the original substrate was non-homogenous due to lateral changes in adjoining microfacies. Multidata analyses indicate that morphological differences in these deep and shallow tracks represent a part of a continuum of track morphologies and geometries produced by a gradient of substrate consistencies across the site. This implies that the large range of track morphologies at this site resulted from similar trackmakers crossing variable facies. The trackways at the El Frontal site present an exemplary case of how track morphology, and consequently potential ichnotaxa, can vary, even when produced by a single trackmaker.", "keyphrases": ["substrate consistency", "spain", "trackway"]}
{"id": "10.1073/pnas.1523951113", "title": "Early farmers from across Europe directly descended from Neolithic Aegeans", "abstract": "Significance One of the most enduring and widely debated questions in prehistoric archaeology concerns the origins of Europe\u2019s earliest farmers: Were they the descendants of local hunter-gatherers, or did they migrate from southwestern Asia, where farming began? We recover genome-wide DNA sequences from early farmers on both the European and Asian sides of the Aegean to reveal an unbroken chain of ancestry leading from central and southwestern Europe back to Greece and northwestern Anatolia. Our study provides the coup de gr\u00e2ce to the notion that farming spread into and across Europe via the dissemination of ideas but without, or with only a limited, migration of people. Farming and sedentism first appeared in southwestern Asia during the early Holocene and later spread to neighboring regions, including Europe, along multiple dispersal routes. Conspicuous uncertainties remain about the relative roles of migration, cultural diffusion, and admixture with local foragers in the early Neolithization of Europe. Here we present paleogenomic data for five Neolithic individuals from northern Greece and northwestern Turkey spanning the time and region of the earliest spread of farming into Europe. We use a novel approach to recalibrate raw reads and call genotypes from ancient DNA and observe striking genetic similarity both among Aegean early farmers and with those from across Europe. Our study demonstrates a direct genetic link between Mediterranean and Central European early farmers and those of Greece and Anatolia, extending the European Neolithic migratory chain all the way back to southwestern Asia.", "keyphrases": ["europe", "neolithic individual", "early farmer"]}
{"id": "10.1080/11250000903143885", "title": "Mitochondrial DNA sequence analysis reveals multiple Pleistocene glacial refugia for Podarcis muralis (Laurenti, 1768) in the Italian Peninsula", "abstract": "Abstract The genetic variability of the wall lizard, Podarcis muralis, was analysed in that part of its range regarded as its area of origin and also its expansion centre. The analysis was performed on partial cytochrome b sequences (405 bp) of 117 specimens representing 31 sampling locations from southern, central and northern Italy. The results of this study revealed 30 haplotypes in the Italian sample belonging to three main genetic lineages. The genetic divergence among haplotypes ranged from 0.2 to 6.6%, whereas the estimation of divergence times among mtDNA lineages highlighted a complex pattern of genetic differentiation with both Pleistocene and Pliocene divergences (3.2\u20130.7 Ma). These results put in evidence the role played by the pre-Pleistocene and Pleistocene palaeogeographic and palaeoclimatic events in shaping the genetic diversity of the wall lizard in Italy and confirm the role of this peninsula as glacial refuge. In addition, AMOVA analysis revealed the presence of geographically structured clades indicating the occurrence of multiple glacial refugia in Italy, thus supporting a refugia-within-refugia scenario for the wall lizard in Italy. Finally, the results of this study seem to indicate a lack of congruence between the four morphological subspecies currently recognised in the Italian Peninsula and the main genetic lineages detected.", "keyphrases": ["glacial refugia", "podarcis muralis", "italian peninsula", "genetic lineage"]}
{"id": "paleo.011726", "title": "Early Human Speciation, Brain Expansion and Dispersal Influenced by African Climate Pulses", "abstract": "Early human evolution is characterised by pulsed speciation and dispersal events that cannot be explained fully by global or continental paleoclimate records. We propose that the collated record of ephemeral East African Rift System (EARS) lakes could be a proxy for the regional paleoclimate conditions experienced by early hominins. Here we show that the presence of these lakes is associated with low levels of dust deposition in both West African and Mediterranean records, but is not associated with long-term global cooling and aridification of East Africa. Hominin expansion and diversification seem to be associated with climate pulses characterized by the precession-forced appearance and disappearance of deep EARS lakes. The most profound period for hominin evolution occurs at about 1.9 Ma; with the highest recorded diversity of hominin species, the appearance of Homo (sensu stricto) and major dispersal events out of East Africa into Eurasia. During this period, ephemeral deep-freshwater lakes appeared along the whole length of the EARS, fundamentally changing the local environment. The relationship between the local environment and hominin brain expansion is less clear. The major step-wise expansion in brain size around 1.9 Ma when Homo appeared was coeval with the occurrence of ephemeral deep lakes. Subsequent incremental increases in brain size are associated with dry periods with few if any lakes. Plio-Pleistocene East African climate pulses as evinced by the paleo-lake records seem, therefore, fundamental to hominin speciation, encephalisation and migration.", "keyphrases": ["dispersal", "african climate pulse", "lake", "hominin evolution"]}
{"id": "10.1671/1870", "title": "THE ANTIQUITY OF AFRICAN TORTOISES", "abstract": "Tortoises (Testudinidae) are a diverse and highly specialized clade of terrestrial turtles that currently inhabit five continents. The global radiation of tortoises in the Paleogene, part of an explosive radiation of testudinoid turtles out of Asia, is poorly understood. The oldest known tortoises are from the late Paleocene of Mongolia (Parham, pers. obs. at PIN), and early in the Eocene they are known to have colonized North America and Europe (e.g., Hutchison, 1998; Lapparent de Broin, 2001). At some point in the early Paleogene they marched or floated to Africa. Today, the ancestors of those first invaders have evolved into the most diverse tortoise fauna in the world; Africa is home to 10 of the 13 extant genera (Iverson, 1992; Lapparent de Broin, 2000). One of the most poorly understood episodes in the early testudinid range expansion is the dispersal of tortoises into Africa. Fossil tortoises have been known from Africa since the beginning of the last century, when Andrews (1902) noted that a \u2018\u2018gigantic land-tortoise\u2019\u2019 had been found by H. J. L. Beadnell. However, the age of these tortoises has never been firmly established, because early collecting records were not precise with regard to the specific quarries from which they were collected. Three species of Testudo were described (Andrews and Beadnell, 1903; Andrews, 1906) as having come from the upper Eocene \u2018\u2018Fluviomarine\u2019\u2019 deposits of the Jebel Qatrani Formation in the Fayum Province of Egypt. In the intervening years, the Jebel Qatrani Formation came to be regarded as early Oligocene in age (e.g., Simons, 1968), then partly late Eocene and partly early Oligocene (Kappelman, 1992; Kappelman et al., 1992). No further testudinids have been reported from Egypt, although fragmentary testudinid fossils possibly close to the Egyptian taxon have been recovered from lower Oligocene sediments in Oman (Thomas et al., 1989; Lapparent de Broin, 2000). Most recently, Lapparent de Broin (2000) reviewed the African fossil record of turtles and conservatively reported the age of the Fayum tortoises as early Oligocene. Resolution of the age of Africa\u2019s oldest tortoises has been difficult because specimens housed in European institutions (Natural History Museum, London, and Staatliches Museum, Stuttgart) lack detailed locality data, and more recent fieldwork in the area by E. L. Simons and crews (materials housed at Yale Peabody Museum, Cairo Geological Museum, and Duke University Primate Center, Durham, North Carolina) has not yielded remains of these comparatively rare reptiles. Reevaluation of older collections from the Jebel Qatrani Formation has uncovered the only African tortoise with associated stratigraphic data indicating a late Eocene age, allowing us to place this taxon in an updated geochronologic context and providing us with the opportunity to resolve several taxonomic issues regarding these specimens. Abbreviations Used AMNH, American Museum of Natural History, New York; BMNH, The Natural History Museum, London; CGM, Cairo Geological Museum, Cairo; PIN, Paleontological Institute, Moscow.", "keyphrases": ["african tortoise", "eocene", "africa"]}
{"id": "10.7554/eLife.17092", "title": "Protein sequences bound to mineral surfaces persist into deep time", "abstract": "Proteins persist longer in the fossil record than DNA, but the longevity, survival mechanisms and substrates remain contested. Here, we demonstrate the role of mineral binding in preserving the protein sequence in ostrich (Struthionidae) eggshell, including from the palaeontological sites of Laetoli (3.8 Ma) and Olduvai Gorge (1.3 Ma) in Tanzania. By tracking protein diagenesis back in time we find consistent patterns of preservation, demonstrating authenticity of the surviving sequences. Molecular dynamics simulations of struthiocalcin-1 and -2, the dominant proteins within the eggshell, reveal that distinct domains bind to the mineral surface. It is the domain with the strongest calculated binding energy to the calcite surface that is selectively preserved. Thermal age calculations demonstrate that the Laetoli and Olduvai peptides are 50 times older than any previously authenticated sequence (equivalent to ~16 Ma at a constant 10\u00b0C). DOI: http://dx.doi.org/10.7554/eLife.17092.001", "keyphrases": ["mineral surface", "longevity", "eggshell", "tanzania", "protein sequence"]}
{"id": "10.1029/2006PA001322", "title": "On the duration of magnetochrons C24r and C25n and the timing of early Eocene global warming events: Implications from the Ocean Drilling Program Leg 208 Walvis Ridge depth transect", "abstract": "[1]\u00a0Five sections drilled in multiple holes over a depth transect of more than 2200 m at the Walvis Ridge (SE Atlantic) during Ocean Drilling Program (ODP) Leg 208 resulted in the first complete early Paleogene deep-sea record. Here we present high-resolution stratigraphic records spanning a \u223c4.3 million yearlong interval of the late Paleocene to early Eocene. This interval includes the Paleocene-Eocene thermal maximum (PETM) as well as the Eocene thermal maximum (ETM) 2 event. A detailed chronology was developed with nondestructive X-ray fluorescence (XRF) core scanning records and shipboard color data. These records were used to refine the shipboard-derived spliced composite depth for each site and with a record from ODP Site 1051 were then used to establish a continuous time series over this interval. Extensive spectral analysis reveals that the early Paleogene sedimentary cyclicity is dominated by precession modulated by the short (100 kyr) and long (405 kyr) eccentricity cycles. Counting of precession-related cycles at multiple sites results in revised estimates for the duration of magnetochrons C24r and C25n. Direct comparison between the amplitude modulation of the precession component derived from XRF data and recent models of Earth's orbital eccentricity suggests that the onset of the PETM and ETM2 are related to a 100-kyr eccentricity maximum. Both events are approximately a quarter of a period offset from a maximum in the 405-kyr eccentricity cycle, with the major difference that the PETM is lagging and ETM2 is leading a 405-kyr eccentricity maximum. Absolute age estimates for the PETM, ETM2, and the magnetochron boundaries that are consistent with recalibrated radiometric ages and recent models of Earth's orbital eccentricity cannot be precisely determined at present because of too large uncertainties in these methods. Nevertheless, we provide two possible tuning options, which demonstrate the potential for the development of a cyclostratigraphic framework based on the stable 405-kyr eccentricity cycle for the entire Paleogene.", "keyphrases": ["duration", "magnetochron c24r", "eocene"]}
{"id": "10.1002/ajpa.22281", "title": "Viewpoints: feeding mechanics, diet, and dietary adaptations in early hominins.", "abstract": "Inference of feeding adaptation in extinct species is challenging, and reconstructions of the paleobiology of our ancestors have utilized an array of analytical approaches. Comparative anatomy and finite element analysis assist in bracketing the range of capabilities in taxa, while microwear and isotopic analyses give glimpses of individual behavior in the past. These myriad approaches have limitations, but each contributes incrementally toward the recognition of adaptation in the hominin fossil record. Microwear and stable isotope analysis together suggest that australopiths are not united by a single, increasingly specialized dietary adaptation. Their traditional (i.e., morphological) characterization as \"nutcrackers\" may only apply to a single taxon, Paranthropus robustus. These inferences can be rejected if interpretation of microwear and isotopic data can be shown to be misguided or altogether erroneous. Alternatively, if these sources of inference are valid, it merely indicates that there are phylogenetic and developmental constraints on morphology. Inherently, finite element analysis is limited in its ability to identify adaptation in paleobiological contexts. Its application to the hominin fossil record to date demonstrates only that under similar loading conditions, the form of the stress field in the australopith facial skeleton differs from that in living primates. This observation, by itself, does not reveal feeding adaptation. Ontogenetic studies indicate that functional and evolutionary adaptation need not be conceptually isolated phenomena. Such a perspective helps to inject consideration of mechanobiological principles of bone formation into paleontological inferences. Finite element analysis must employ such principles to become an effective research tool in this context.", "keyphrases": ["dietary adaptation", "morphology", "tooth", "assumption"]}
{"id": "10.1073/pnas.1416072111", "title": "American mastodon extirpation in the Arctic and Subarctic predates human colonization and terminal Pleistocene climate change", "abstract": "Significance New radiocarbon (14C) dates on American mastodon (Mammut americanum) fossils in Alaska and Yukon suggest this species suffered local extirpation before terminal Pleistocene climate changes or human colonization. Mastodons occupied high latitudes during the Last Interglacial (\u223c125,000\u201375,000 y ago) when forests were established. Ecological changes during the Wisconsinan glaciation (\u223c75,000 y ago) led to habitat loss and population collapse. Thereafter, mastodons were limited to areas south of the continental ice sheets, where they ultimately died out \u223c10,000 14C years B.P. Extirpation of mastodons and some other megafaunal species in high latitudes was thus independent of their later extinction south of the ice. Rigorous pretreatment was crucial to removing contamination from fossils that originally yielded erroneously \u201cyoung\u201d 14C dates. Existing radiocarbon (14C) dates on American mastodon (Mammut americanum) fossils from eastern Beringia (Alaska and Yukon) have been interpreted as evidence they inhabited the Arctic and Subarctic during Pleistocene full-glacial times (\u223c18,000 14C years B.P.). However, this chronology is inconsistent with inferred habitat preferences of mastodons and correlative paleoecological evidence. To establish a last appearance date (LAD) for M. americanum regionally, we obtained 53 new 14C dates on 36 fossils, including specimens with previously published dates. Using collagen ultrafiltration and single amino acid (hydroxyproline) methods, these specimens consistently date to beyond or near the \u223c50,000 y B.P. limit of 14C dating. Some erroneously \u201cyoung\u201d 14C dates are due to contamination by exogenous carbon from natural sources and conservation treatments used in museums. We suggest mastodons inhabited the high latitudes only during warm intervals, particularly the Last Interglacial [Marine Isotope Stage (MIS) 5] when boreal forests existed regionally. Our 14C dataset suggests that mastodons were extirpated from eastern Beringia during the MIS 4 glacial interval (\u223c75,000 y ago), following the ecological shift from boreal forest to steppe tundra. Mastodons thereafter became restricted to areas south of the continental ice sheets, where they suffered complete extinction \u223c10,000 14C years B.P. Mastodons were already absent from eastern Beringia several tens of millennia before the first humans crossed the Bering Isthmus or the onset of climate changes during the terminal Pleistocene. Local extirpations of mastodons and other megafaunal populations in eastern Beringia were asynchrononous and independent of their final extinction south of the continental ice sheets.", "keyphrases": ["arctic", "human colonization", "pleistocene climate change", "continental ice sheet"]}
{"id": "10.1130/G34164.1", "title": "Evidence for an African-Iberian mammal dispersal during the pre-evaporitic Messinian", "abstract": "The accurate timing of biogeographic dispersal can be determined by examining the age of fossiliferous strata on either side of a physical barrier. Here we show that African mammals migrated to Iberia and European mammals migrated to North Africa at the same time before isolation of the Mediterranean Sea during the Messinian. The fossil site of Venta del Moro (Spain) exhibits western Europe\u2019s most complete vertebrate fauna for the latest Miocene. Its uniquely cosmopolitan assemblage is evidence of faunal dispersals from Africa and Asia to Europe during the latest Miocene glaciation. A preliminary paleomagnetic study suggested an age of 5.8 Ma for this site, but our expanded magnetostratigraphy dates the site at 6.23 Ma. In addition, we recalibrated the paleomagnetic age of the Librilla site (Spain) and the North Africa site of Afoud-1 (Morocco) using the Astronomical Tuned Neogene Time Scale. Our results show a two-way African-Iberian mammal dispersal just before 6.2 Ma. These new ages indicate that an ephemeral land corridor existed between the two continents 250 k.y. before the onset of the Messinian Salinity Crisis, reflecting a tentative initial isolation of the Mediterranean Sea. This corridor developed after tectonics closed the Betic Seaway at 6.3 Ma and during the intensification of the latest Miocene glaciation at 6.26 Ma, when water circulation in the Mediterranean became very restricted.", "keyphrases": ["african-iberian mammal dispersal", "venta del moro", "late miocene"]}
{"id": "10.1098/rspb.2010.1280", "title": "Pseudogenization of the tooth gene enamelysin (MMP20) in the common ancestor of extant baleen whales", "abstract": "Whales in the suborder Mysticeti are filter feeders that use baleen to sift zooplankton and small fish from ocean waters. Adult mysticetes lack teeth, although tooth buds are present in foetal stages. Cladistic analyses suggest that functional teeth were lost in the common ancestor of crown-group Mysticeti. DNA sequences for the tooth-specific genes, ameloblastin (AMBN), enamelin (ENAM) and amelogenin (AMEL), have frameshift mutations and/or stop codons in this taxon, but none of these molecular cavities are shared by all extant mysticetes. Here, we provide the first evidence for pseudogenization of a tooth gene, enamelysin (MMP20), in the common ancestor of living baleen whales. Specifically, pseudogenization resulted from the insertion of a CHR-2 SINE retroposon in exon 2 of MMP20. Genomic and palaeontological data now provide congruent support for the loss of enamel-capped teeth on the common ancestral branch of crown-group mysticetes. The new data for MMP20 also document a polymorphic stop codon in exon 2 of the pygmy sperm whale (Kogia breviceps), which has enamel-less teeth. These results, in conjunction with the evidence for pseudogenization of MMP20 in Hoffmann's two-toed sloth (Choloepus hoffmanni), another enamel-less species, support the hypothesis that the only unique, non-overlapping function of the MMP20 gene is in enamel formation.", "keyphrases": ["common ancestor", "baleen whale", "tooth-specific gene", "frameshift mutation", "pseudogenization"]}
{"id": "paleo.001155", "title": "Ontogenetic variability in crystallography and mosaicity of conodont apatite: implications for microstructure, palaeothermometry and geochemistry", "abstract": "X-ray diffraction data from Silurian conodonts belonging to various developmental stages of the species Dapsilodus obliquicostatus demonstrate changes in crystallography and degree of nanocrystallite ordering (mosaicity) in both lamellar crown tissue and white matter. The exclusive use of a single species in this study, combined with systematic testing of each element type at multiple locations, provided insight into microstructural and crystallographic differentiation between element type (Sa, Sb-c, M) as well as between juveniles and adults. A relative increase in the unit cell dimensions a/c ratio of nanocrystallites during growth was apparent in areas demonstrating single-crystal behaviour, but no such relationship was seen in dominantly polycrystalline areas. Systematic variations in mosaicity were identified, with mosaicity (as a proxy for disorder) increasing during growth, as well as along elements from tip to base. These results provide potential insight into the integrity of conodont apatite as a recorder of palaeoseawater chemistry, as well as demonstrate the need to consider the influence of ontogeny and element type on the use of conodonts in palaeothermometry and geochemical investigations.", "keyphrases": ["crystallography", "conodont apatite", "palaeothermometry", "lamellar crown tissue"]}
{"id": "paleo.005585", "title": "The most basal ankylosaurine dinosaur from the Albian\u2013Cenomanian of China, with implications for the evolution of the tail club", "abstract": "The tail club knob is a highly specialized structure thought to characterize a subgroup of the ankylosaurine ankylosaurians, and the oldest documented tail club knob in the fossil record occurred in the Campanian ankylosaurine Pinacosaurus. Here we report a new ankylosaurid Jinyunpelta sinensis, gen. et sp. nov., from the Albian\u2013Cenomanian Liangtoutang Formation, Jinyun County, Zhejiang, China. This is the first definitive and the best preserved ankylosaurid dinosaur ever found in southern China. Jinyunpelta possesses unique cranial features differs from other ankylosaurs including two paranasal apertures level with and posterior to the external naris, a triangular fossa on the anterodorsal edge of the maxilla, an antorbital fossa in the junction between the maxilla, lacrimal and jugal, and an anterior process of the prearticular that lies ventral to the splenial. Our phylogenetic analysis suggests Jinyunpelta as the most basal ankylosaurine dinosaur. Jinyunpelta has a tail club with interlocking caudal vertebrae and a well-developed tail club knob, it represents the oldest and the most basal ankylosaurian known to have a well-developed tail club knob. The new discovery thus demonstrates that a large and highly modified tail club evolved at the base of the ankylosaurine ankylosaurs at least about 100 million years ago.", "keyphrases": ["basal ankylosaurine dinosaur", "albian\u2013cenomanian liangtoutang formation", "ankylosaur"]}
{"id": "10.1098/rspb.2009.1494", "title": "Lower limits of ornithischian dinosaur body size inferred from a new Upper Jurassic heterodontosaurid from North America", "abstract": "The extremes of dinosaur body size have long fascinated scientists. The smallest (<1 m length) known dinosaurs are carnivorous saurischian theropods, and similarly diminutive herbivorous or omnivorous ornithischians (the other major group of dinosaurs) are unknown. We report a new ornithischian dinosaur, Fruitadens haagarorum, from the Late Jurassic of western North America that rivals the smallest theropods in size. The largest specimens of Fruitadens represent young adults in their fifth year of development and are estimated at just 65\u201375 cm in total body length and 0.5\u20130.75 kg body mass. They are thus the smallest known ornithischians. Fruitadens is a late-surviving member of the basal dinosaur clade Heterodontosauridae, and is the first member of this clade to be described from North America. The craniodental anatomy and diminutive body size of Fruitadens suggest that this taxon was an ecological generalist with an omnivorous diet, thus providing new insights into morphological and palaeoecological diversity within Dinosauria. Late-surviving (Late Jurassic and Early Cretaceous) heterodontosaurids are smaller and less ecologically specialized than Early (Late Triassic and Early Jurassic) heterodontosaurids, and this ecological generalization may account in part for the remarkable 100-million-year-long longevity of the clade.", "keyphrases": ["ornithischian dinosaur", "dinosaur body size", "theropod"]}
{"id": "paleo.003490", "title": "Bacteria or melanosomes? A geochemical analysis of micro-bodies on a tadpole from the Oligocene Enspel Formation of Germany", "abstract": "Many exceptionally preserved fossils have long been thought the product of preservation by bacterial autolithification, based largely upon the presence of, micronsized, spherical or elongate bodies on their surface. This has recently been challenged by studies of similar fossils which cite morphological and geochemical evidence that these structures could be fossilized melanosomes, melanin-containing organelles. We geochemically analysed a tadpole from the Oligocene Enspel Formation, Germany, which displays such spherical bodies on its surface. Pyrolysis gas chromatography mass spectroscopy (Py-GCMS) and Fourier transform infrared spectrometry (FTIR) indicate that the organic remains of the tadpole are original and are not the result of external contamination, shown by the different chemical compositions of the fossil and its enclosing matrix. Py-GCMS also demonstrates the presence of bacterial and plant biomarkers in the matrix but not the tadpole, suggesting that the spherical bodies are unlikely to be bacterial, and also that such fossils do not develop their dark colour from incorporating plant material, as has been suggested. X-ray absorption spectroscopy (XAS)\nshows high levels of organically bound Zn(II) in the fossilized soft tissue, a metal known to chelate both eu-and pheomelanin. The zinc in the tadpole shows greater similarity to that bound in pheomelanized extant samples than to that in eumelanized ones. Though further geochemical analysis of both pure pheomelanin and bacterial samples is required to completely exclude a bacterial origin, these results are in line with a pheomelanic origin for the spherical bodies on the tadpole.", "keyphrases": ["melanosome", "geochemical analysis", "oligocene enspel formation", "x-ray absorption spectroscopy", "xas"]}
{"id": "10.1002/ajpa.21489", "title": "Comparing Dirichlet normal surface energy of tooth crowns, a new technique of molar shape quantification for dietary inference, with previous methods in isolation and in combination.", "abstract": "Inferred dietary preference is a major component of paleoecologies of extinct primates. Molar occlusal shape correlates with diet in living mammals, so teeth are a potentially useful structure from which to reconstruct diet in extinct taxa. We assess the efficacy of Dirichlet normal energy (DNE) calculated for molar tooth surfaces for reflecting diet. We evaluate DNE, which uses changes in normal vectors to characterize curvature, by directly comparing this metric to metrics previously used in dietary inference. We also test whether combining methods improves diet reconstructions. The study sample consisted of 146 lower (mandibular) second molars belonging to 24 euarchontan taxa. Five shape quantification metrics were calculated on each molar: DNE, shearing quotient, shearing ratio, relief index, and orientation patch count rotated (OPCR). Statistical analyses were completed for each variable to assess effects of taxon and diet. Discriminant function analysis was used to assess ability of combinations of variables to predict diet. Values differ significantly by diets for all variables, although shearing ratios and OPCR do not distinguish statistically between insectivores and folivores or omnivores and frugivores. Combined analyses were much more effective at predicting diet than any metric alone. Alone, relief index and DNE were most effective at predicting diet. OPCR was the least effective alone but is still valuable as the only quantitative measure of surface complexity. Of all methods considered, DNE was the least methodologically sensitive, and its effectiveness suggests it will be a valuable tool for dietary reconstruction.", "keyphrases": ["dirichlet", "dietary inference", "dne"]}
{"id": "10.3176/earth.2010.1.01", "title": "Hirnantian (latest Ordovician) bio- and chemostratigraphy of the Stirnas-18 core, western Latvia", "abstract": "Integrated study of the uppermost Ordovician Porkuni Stage in the Stirnas-18 core, western Latvia, has revealed one of the most complete Hirnantian successions in the eastern Baltic region. The interval is characterized by two shallowing upwards depositional sequences that correspond to the Kuldiga and Saldus formations. The whole-rock carbon stable isotope curve indicates a long rising segment of the Hirnantian carbon isotope excursion, with the highest peak in the upper part of the Kuldiga Formation. The bioclast carbon and oxygen curves fit well with the whole-rock carbon data. Microand macrofossil data enabled seven combined associations to be distinguished within the Hirnantian strata. The early Porkuni fauna of the Spinachitina taugourdeaui Biozone, with pre-Hirnantian affinities, is succeeded by an interval with a Hindella\u0096Cliftonia brachiopod association, a specific polychaete fauna, the chitinozoan Conochitina scabra, and the conodont Noixodontus girardeauensis. The middle part of the Kuldiga Formation is characterized by a low-diversity Dalmanella testudinaria brachiopod association, high diversity of scolecodonts, and the occurrence of the chitinozoan Lagenochitina prussica. From the middle part of the Kuldiga Formation the youngest occurrence yet known of the conodont Amorphognathus ordovicicus is reported. Also typical of the Kuldiga Formation is the occurrence of the trilobite Mucronaspis mucronata. The uppermost Hirnantian Saldus Formation contains no shelly fauna, but yields redeposited conodonts and at least partly indigenous chitinozoans and scolecodonts. Palaeontological criteria and stable isotope data enable correlation of the Stirnas section with other Hirnantian successions in the Baltic region and elsewhere.", "keyphrases": ["ordovician", "western latvia", "chitinozoan"]}
{"id": "paleo.001732", "title": "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans", "abstract": "The Late Cretaceous (\u223c95\u201366 million years ago) western North American landmass of Laramidia displayed heightened non-marine vertebrate diversity and intracontinental regionalism relative to other latest Cretaceous Laurasian ecosystems. Processes generating these patterns during this interval remain poorly understood despite their presumed role in the diversification of many clades. Tyrannosauridae, a clade of large-bodied theropod dinosaurs restricted to the Late Cretaceous of Laramidia and Asia, represents an ideal group for investigating Laramidian patterns of evolution. We use new tyrannosaurid discoveries from Utah\u2014including a new taxon which represents the geologically oldest member of the clade\u2014to investigate the evolution and biogeography of Tyrannosauridae. These data suggest a Laramidian origin for Tyrannosauridae, and implicate sea-level related controls in the isolation, diversification, and dispersal of this and many other Late Cretaceous vertebrate clades.", "keyphrases": ["late cretaceous", "laramidia", "tyrannosaurid", "biogeography", "genealogy"]}
{"id": "paleo.011855", "title": "Rapid Recovery of Life at Ground Zero of the End Cretaceous Mass Extinction", "abstract": "The Cretaceous-Paleogene (K-Pg) mass extinction eradicated 76% of species on Earth1,2. It was caused by the impact of an asteroid3,4 on the Yucat\u00e1n carbonate platform in the southern Gulf of Mexico at 66.0 Ma5 which formed the Chicxulub impact crater6,7. Following the mass extinction, recovery of the global marine ecosystem, measured in terms of primary productivity, was geographically heterogeneous8, as export production in the Gulf of Mexico and North Atlantic/Tethys took 300 kyr to return to Late Cretaceous quantities, slower than most other regions8\u201311. Delayed recovery of marine productivity closer to the crater implies an impact-related environmental control, like toxic metal poisoning12, on recovery times. Conversely, if no such geographic pattern exists, the best explanation for the observed heterogeneity is ecological, based on trophic interactions13, species incumbency and competitive exclusion by opportunists14, and \u201cchance\u201d8,15,16. Importantly, this question has bearing on the inherent predictability (or lack thereof) of future patterns of recovery in modern anthropogenically perturbed ecosystems. If there is a relationship between the distance from the impact and the recovery of marine productivity, we would expect recovery rates to be slowest in the crater itself. Here, we present the first record of foraminifera, calcareous nannoplankton, trace fossils, and elemental abundance data from the first ~200 kyr of the Paleocene within the Chicxulub Crater. We show that life reappeared in the basin just years after the impact and a thriving, high-productivity ecosystem was established within 30 kyr, faster than many sites across the globe. This is a clear indication that proximity to the impact did not delay recovery and thus there was no impact-related environmental control on recovery. Ecological processes likely controlled the recovery of productivity after the K-Pg mass extinction and are therefore likely to be significant in the response of the ocean ecosystem to other rapid extinction events.", "keyphrases": ["recovery", "trace fossil", "extinction event"]}
{"id": "paleo.002748", "title": "Convergence and functional evolution of longirostry in crocodylomorphs", "abstract": "During the Mesozoic, Crocodylomorpha had a much higher taxonomic and morphological diversity than today. Members of one particularly successful clade, Thalattosuchia, are well\u2010known for being longirostrine: having long, slender snouts. It has generally been assumed that Thalattosuchia owed their success in part to the evolution of longirostry, leading to a feeding ecology similar to that of the living Indian gharial, Gavialis. Here, we compare form and function of the skulls of the thalattosuchian Pelagosaurus and Gavialis using digital reconstructions of the skull musculoskeletal anatomy and finite element models to show that they had different jaw muscle arrangements and biomechanical behaviour. Additionally, the relevance of feeding\u2010related mandibular traits linked to longirostry in the radiation of crocodylomorph clades was investigated by conducting an evolutionary rates analysis under the variable rates model. We find that, even though Pelagosaurus and Gavialis share similar patterns of stress distribution in their skulls, the former had lower mechanical resistance. This suggests that compared to Gavialis, Pelagosaurus was unable to process large, mechanically less tractable prey, instead operating as a specialized piscivore that fed on softer and smaller prey. Secondly, innovation of feeding strategies was achieved by rate acceleration of functional characters of the mandible, a key mechanism for the diversification of certain clades like thalattosuchians and eusuchians. Different rates of functional evolution suggest divergent diversification dynamics between teleosaurids and metriorhynchids in the Jurassic.", "keyphrases": ["functional evolution", "longirostry", "snout", "ecology"]}
{"id": "paleo.005363", "title": "Rearfoot posture of Australopithecus sediba and the evolution of the hominin longitudinal arch", "abstract": "The longitudinal arch is one of the hallmarks of the human foot but its evolutionary history remains controversial due to the fragmentary nature of the fossil record. In modern humans, the presence of a longitudinal arch is reflected in the angular relationships among the major surfaces of the human talus and calcaneus complex, which is also known as the rearfoot. A complete talus and calcaneus of Australopithecus sediba provide the opportunity to evaluate rearfoot posture in an early hominin for the first time. Here I show that A. sediba is indistinguishable from extant African apes in the angular configuration of its rearfoot, which strongly suggests that it lacked a longitudinal arch. Inferences made from isolated fossils support the hypothesis that Australopithecus afarensis possessed an arched foot. However, tali attributed to temporally younger taxa like Australopithecus africanus and Homo floresiensis are more similar to those of A. sediba. The inferred absence of a longitudinal arch in A. sediba would be biomechanically consistent with prior suggestions of increased midtarsal mobility in this taxon. The morphological patterns in talus and calcaneus angular relationships among fossil hominins suggest that there was diversity in traits associated with the longitudinal arch in the Plio-Pleistocene.\nThe longitudinal arch of the human foot aids in propulsion and represents an energy-saving and shock-absorbing mechanism that is part of a suite of midfoot stabilizing morphologies associated with a commitment to terrestrial locomotion 1-3 . Great apes lack these specializations for terrestrial locomotion and instead have much more mobile feet that are more suited to vertical climbing and arboreality 4,5 . Whether or not early hominins possessed a modern human-like longitudinal arch is controversial, in large part because few of the relevant foot fossils have been recovered. Of the hominin species that do preserve the relevant morphology, Ardipithecus ramidus (4.4 Ma) possessed an abducted hallux, which precludes a modern human-like longitudinal arch 6 . Foot fossils attributed to A. afarensis are found at Afar Locality 333 at Hadar, Ethiopia 7,8 , although there is a talus and two phalanges associated with the A.L. 288-1 partial skeleton. The A. afarensis foot skeleton has a mix of some ape-like traits (e.g., long, curved phalanges), and several traits derived in the direction of modern humans (e.g., talocrural joint orthogonal to tibia, robust calcaneal tuber). Previous researchers have suggested that A. afarensis lacked a longitudinal arch based on prominent tuberosities on the lateral cuneiform (A.L. 333-79) and naviculars (A.L. 333-36, -47) 9-11 . However, Australopithecus afarensis (3.8-2.9 Ma) is now generally agreed to have had a longitudinal arch, as demonstrated most clearly in the morphology of a complete fourth metatarsal 2,8 (but see ref. 12 for an alternative view) and the attribution of the Laetoli fossil footprints (3.7 Ma) to this taxon 13, 14 .", "keyphrases": ["australopithecus sediba", "hominin", "locomotion", "rearfoot posture"]}
{"id": "paleo.005234", "title": "Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time", "abstract": "Isolated small theropod teeth are abundant in vertebrate microfossil assemblages, and are frequently used in studies of species diversity in ancient ecosystems. However, determining the taxonomic affinities of these teeth is problematic due to an absence of associated diagnostic skeletal material. Species such as Dromaeosaurus albertensis, Richardoestesia gilmorei, and Saurornitholestes langstoni are known from skeletal remains that have been recovered exclusively from the Dinosaur Park Formation (Campanian). It is therefore likely that teeth from different formations widely disparate in age or geographic position are not referable to these species. Tooth taxa without any associated skeletal material, such as Paronychodon lacustris and Richardoestesia isosceles, have also been identified from multiple localities of disparate ages throughout the Late Cretaceous. To address this problem, a dataset of measurements of 1183 small theropod teeth (the most specimen-rich theropod tooth dataset ever constructed) from North America ranging in age from Santonian through Maastrichtian were analyzed using multivariate statistical methods: canonical variate analysis, pairwise discriminant function analysis, and multivariate analysis of variance. The results indicate that teeth referred to the same taxon from different formations are often quantitatively distinct. In contrast, isolated teeth found in time equivalent formations are not quantitatively distinguishable from each other. These results support the hypothesis that small theropod taxa, like other dinosaurs in the Late Cretaceous, tend to be exclusive to discrete host formations. The methods outlined have great potential for future studies of isolated teeth worldwide, and may be the most useful non-destructive technique known of extracting the most data possible from isolated and fragmentary specimens. The ability to accurately assess species diversity and turnover through time based on isolated teeth will help illuminate patterns of evolution and extinction in these groups and potentially others in greater detail than has previously been thought possible without more complete skeletal material.", "keyphrases": ["theropod tooth", "statistical method", "future study", "isolated tooth"]}
{"id": "10.1017/S0016756818000110", "title": "Palaeolatitudinal distribution of lithologic indicators of climate in a palaeogeographic framework", "abstract": "Abstract Whether the latitudinal distribution of climate-sensitive lithologies is stable through greenhouse and icehouse regimes remains unclear. Previous studies suggest that the palaeolatitudinal distribution of palaeoclimate indicators, including coals, evaporites, reefs and carbonates, has remained broadly similar since the Permian period, leading to the conclusion that atmospheric and oceanic circulation control their distribution rather than the latitudinal temperature gradient. Here we revisit a global-scale compilation of lithologic indicators of climate, including coals, evaporites and glacial deposits, back to the Devonian period. We test the sensitivity of their latitudinal distributions to the uneven distribution of continental areas through time and to global tectonic models, correct the latitudinal distributions of lithologies for sampling- and continental area-bias, and use statistical methods to fit these distributions with probability density functions and estimate their high-density latitudinal ranges with 50% and 95% confidence intervals. The results suggest that the palaeolatitudinal distributions of lithologies have changed through deep geological time, notably a pronounced poleward shift in the distribution of coals at the beginning of the Permian. The distribution of evaporites indicates a clearly bimodal distribution over the past ~400 Ma, except for Early Devonian, Early Carboniferous, the earliest Permian and Middle and Late Jurassic times. We discuss how the patterns indicated by these lithologies change through time in response to plate motion, orography, evolution and greenhouse/icehouse conditions. This study highlights that combining tectonic reconstructions with a comprehensive lithologic database and novel data analysis approaches provide insights into the nature and causes of shifting climatic zones through deep time.", "keyphrases": ["indicator", "evaporite", "glacial deposit", "palaeolatitudinal distribution"]}
{"id": "paleo.002942", "title": "OLDEST PLACENTAL MAMMAL FROM SUB-SAHARAN AFRICA: EOCENE MICROBAT FROM TANZANIA -EVIDENCE FOR EARLY EVOLUTION OF SOPHISTICATED ECHOLOCATION", "abstract": "A partial skeleton of a new fossil microbat, Tanzanycteris mannardi, is the oldest placental mammal found in sub-Saharan Africa. It came from early Lutetian (46 Ma) lake sediments in north-central Tanzania. T. mannardi has enlarged cochleae indicating it was capable of a highly derived form of echolocation. Modern bats sharing similar morphology are capable of precise navigation in dense forest undergrowth. The phylogenetic relationships of T. mannardi are unclear. It shares character states with Eocene Hassianycterididae, with extant Microchiroptera, and with Rhinolophoidea within Microchiroptera. T. mannardi is important in documenting early evolution of sophisticated bat echolocating abilities and demonstrating that Tanzanian crater lakes offer an opportunity for future discoveries of Eocene mammals from the African interior.", "keyphrases": ["tanzania", "early evolution", "echolocation"]}
{"id": "10.1146/annurev-earth-042711-105515", "title": "Paleobiology of Herbivorous Dinosaurs", "abstract": "Herbivorous dinosaurs were abundant, species-rich components of Late Triassic\u2013Cretaceous terrestrial ecosystems. Obligate high-fiber herbivory evolved independently on several occasions within Dinosauria, through the intermediary step of omnivory. Anatomical character complexes associated with this diet exhibit high levels of convergence and morphological disparity, and may have evolved by correlated progression. Dinosaur faunas changed markedly during the Mesozoic, from early faunas dominated by taxa with simple, uniform feeding mechanics to Cretaceous biomes including diverse sophisticated sympatric herbivores; the environmental and biological drivers causing these changes remain unclear. Isotopic, taphonomic, and anatomical evidence implies that niche partitioning reduced competition between sympatric herbivores, via morphological differentiation, dietary preferences, and habitat selection. Large body size in dinosaur herbivores is associated with low plant productivity, and gave these animals prominen...", "keyphrases": ["herbivorous dinosaur", "ecosystem", "mesozoic", "body size", "sauropod"]}
{"id": "paleo.003270", "title": "Evolution of parental incubation behaviour in dinosaurs cannot be inferred from clutch mass in birds", "abstract": "A recent study proposed that incubation behaviour (i.e. type of parental care) in theropod dinosaurs can be inferred from an allometric analysis of clutch volume in extant birds. However, the study in question failed to account for factors known to affect egg and clutch size in living bird species. A new scaling analysis of avian clutch mass demonstrates that type of parental care cannot be distinguished by conventional allometry because of the confounding effects of phylogeny and hatchling maturity. Precociality of young but not paternal care in the theropod ancestors of birds is consistent with the available data.", "keyphrases": ["incubation behaviour", "clutch mass", "parental care", "extant bird", "egg"]}
{"id": "paleo.000291", "title": "ORIGIN, EVOLUTION AND CLASSIFICATION OF THE NEW SUPERORDER NEPIOMORPHIA (MOLLUSCA, BIVALVIA, LOWER PALAEOZOIC)", "abstract": "Abstract:\u2002 A number of bivalve taxa defined in the past as \u2018Cryptodonten\u2019 by Neumayr, 1884 were grouped together in the high\u2010level taxon Palaeoconchae Neumayr, 1884. Cox (1969) noted that Palaeoconchae and Cryptodonta were synonymous and Newell (1969) used Cryptodonta as a subclass of bivalves. However, for the past 120\u2003years, the Cryptodonta has been poorly conceptualized and the name was used for poorly understood genera or those lacking dentition. As used by Newell, Cryptodonta included taxa now placed in the subclasses Protobranchia Pelseneer and Autolamellibranchiata Grobben, and to the class Rostroconchia Pojeta, Runnegar, Morris and Newell. The bulk of Newell's use of Cryptodonta was made up of Silurian and Devonian taxa first described by Barrande (1881) from Bohemia; Newell placed these in the order Praecardioida Newell. In effect, Cryptodonta became a \u2018wastebasket\u2019 grouping for what, at the time, were poorly understood taxa. Many of the formerly poorly understood praecardioids are now better known and are herein placed in the new superorder Nepiomorphia. The Nepiomorphia contains two orders: (1) order Praecardioida that includes the families Slavidae K\u0159\u00ed\u017e, Cardiolidae Hoernes, Praecardiidae Hoernes and Buchiolidae Grimm; and (2) new order Antipleuroida that includes the families Stolidotidae fam. nov., Spanilidae fam. nov. and Antipleuridae Neumayr. The Nepiomorphia originated probably in the early Silurian as result of r\u2010selection progenesis. When the marine current system became re\u2010established after the late Ordovician glaciation and in the early Silurian, an at least temporary ventilation of the shallow waters by surface currents was renewed in higher latitudes of peri\u2010Gondwana and Siberia, producing acceptable sea\u2010bottom environments. Larvae were distributed by surface currents from the warm tropical regions of Laurentia and Baltica and were among the first benthic organisms to colonize the new environments. Temporary ventilation created frequent density\u2010independent catastrophic mortalities of early ontogenetic stages, with no competitors and with super\u2010abundant resources. During the Silurian and early Devonian, the Nepiomorphia underwent several diversifications in the recurring cephalopod limestone biofacies characteristic of peri\u2010Gondwana, and evolved infaunal, semi\u2010infaunal and epifaunal modes of life in several lineages. The Nepiomorphia most probably became extinct during the early Carboniferous and had no role in the future evolution of the Bivalvia.", "keyphrases": ["new superorder nepiomorphia", "bivalvia", "phylogenetic remark", "family cardiolidae"]}
{"id": "10.2110/palo.2010.p10-135r", "title": "REEF RECOVERY FOLLOWING THE FRASNIAN\u2013FAMENNIAN (LATE DEVONIAN) MASS EXTINCTION: EVIDENCE FROM THE DUGWAY RANGE, WEST-CENTRAL UTAH", "abstract": "ABSTRACT The temporally extensive late Middle through Late Devonian biotic crisis involved at least three distinct peaks of elevated extinction intensity during an interval spanning \u223c25 myr and resulted in the preferential elimination of certain shallow-marine, warm-water taxa, especially members of reef communities. By the end of the second peak, delimited by the Frasnian\u2013Famennian (F\u2013F) boundary, the stromatoporoids, members of the dominant constructor guild in mid-Paleozoic reefal ecosystems, had ceased building reefs in most parts of the world. The northern Dugway Range in west-central Utah, United States, however, represents one of the few locations globally where stromatoporoids continued reef building into the Famennian. Two measured sections there, which are constrained biostratigraphically using conodonts, indicate that the biohermal sequences occur within the middle Palmatolepis crepida biozone and are early Famennian in age. The post-F\u2013F extinction Dugway reefal faunas are depauperate and dominated by labechiid and stylostromid stromatoporoids, as is characteristic of other early Famennian reefs. In this region, evidence for reefal development is episodic, with stromatoporoid-bearing units interbedded with peloidal and coated-grain carbonate units lacking evidence of reef construction. The stromatoporoid survivors, although fairly minor constituents of Frasnian reef communities, belong to long-ranging clades and may represent so-called extinction-resistant taxa that flourished, albeit locally in Laurentia, following the F\u2013F mass extinction.", "keyphrases": ["frasnian\u2013famennian", "dugway range", "west-central utah", "biotic crisis"]}
{"id": "10.1017/pab.2015.19", "title": "Maiasaura, a model organism for extinct vertebrate population biology: a large sample statistical assessment of growth dynamics and survivorship", "abstract": "Abstract \n Fossil bone microanalyses reveal the ontogenetic histories of extinct tetrapods, but incomplete fossil records often result in small sample sets lacking statistical strength. In contrast, a histological sample of 50 tibiae of the hadrosaurid dinosaur Maiasaura peeblesorum allows predictions of annual growth and ecological interpretations based on more histologic data than any previous large sample study. Tibia length correlates well (R2 > 0.9) with diaphyseal circumference, cortical area, and bone wall thickness, thereby allowing longitudinal predictions of annual body size increases based on growth mark circumference measurements. With an avian level apposition rate of 86.4 \u00b5m/day, Maiasaura achieved over half of asymptotic tibia diaphyseal circumference within its first year. Mortality rate for the first year was 89.9% but a seven year period of peak performance followed, when survivorship (mean mortality rate = 12.7%) was highest. During the third year of life, Maiasaura attained 36% (x = 1260 kg) of asymptotic body mass, growth rate was decelerating (18.2 \u00b5m/day), cortical vascular orientation changed, and mortality rate briefly increased. These transitions may indicate onset of sexual maturity and corresponding reallocation of resources to reproduction. Skeletal maturity and senescence occurred after 8 years, at which point the mean mortality rate increased to 44.4%. Compared with Alligator, an extant relative, Maiasaura exhibits rapid cortical increase early in ontogeny, while Alligator cortical growth is much lower and protracted throughout ontogeny. Our life history synthesis of Maiasaura utilizes the largest histological sample size for any extinct tetrapod species thus far, demonstrating how large sample microanalyses strengthen paleobiological interpretations.", "keyphrases": ["survivorship", "growth rate", "maiasaura", "crocodylian"]}
{"id": "paleo.005627", "title": "Longibelus gen. nov., a new Cretaceous coleoid genus linking Belemnoidea and early Decabrachia", "abstract": "The phylogenetic origin and the timing of origination of the Decabrachia are controversial. This is due to a poor understanding of character complexes relating to the shell, which causes difficulties in establishing homologies among different taxa. One central problem concerns a clear differentiation between belemnoids and early spirulids. A comparative analysis of shell structures of well\u2010preserved specimens including types and new material of Cretaceous spirulids Groenlandibelus, Naefia and Cyrtobelus, as well as selected taxa of aulacocerid, belemnitid and diplobelid belemnoids, revealed a set of 14 characters. Seven characters (apical angle, chamber length, dorsal and ventral sutures, orientation of septa, direction of the dorsal part of the septal neck, primordial rostrum) are not or less diagnostic, whereas the seven remaining characters can be reliably used to distinguish between the Decabrachia on the one hand and Belemnitida and Aulacocerida on the other hand. These diagnostic characters are as follows: (1) presence/absence of a mural flap; (2) position of the siphuncle; (3) shape of the dorsal soft tissue attachment scar; (4) presence/absence of tabular nacre in the conotheca; (5) presence/absence of a rostrum proper; (6) presence/absence of a narrow rod\u2010like proostracum; and (7) presence/absence of a caecum. Diplobelida and \u2018Naefia\u2019 matsumotoi, however, exhibit a mosaic of decabrachian and belemnoid characters. Owing to striking differences between N. neogaiea, the type species of Naefia, and \u2018N.\u2019 matsumotoi, the new genus Longibelus has been erected. Besides a redescription of Longibelus (\u2018Naefia\u2019) matsumotoi, we describe the first Maastrichtian occurrences of this species from Hokkaido (northern Japan) and Alaska. Among the type material of N. neogaiea from the Maastrichtian of Chile, we found one specimen that unambiguously belongs to Longibelus gen. nov. Similarly, two specimens from the Maastrichtian of Mexico previously determined as N. neogaiea also belong to the new genus. Also, we can reinterpret material from the Cenomanian of India as Longibelus gen. nov. New material from the Albian of India likewise assignable to Longibelus is described for the first time. Finally, we introduce the first records of coleoids from Zululand (South Africa). These specimens belong to Longibelus as do specimens from the Aptian of Caucasus (previously described as \u2018Naefia\u2019 kabanovi). A phylogenetic approach suggests that Longibelus gen. nov. is derived from diplobelid\u2010like belemnoids and gave rise for the Decabrachia or at least groenlandibelid spirulids. This strongly supports earlier ideas on a close relationship between Cretaceous Decabrachia and belemnites and simultaneously challenges opinions that Decabrachia originated in the Carboniferous.", "keyphrases": ["coleoid", "belemnoidea", "diplobelida", "northern japan", "longibelus"]}
{"id": "10.1111/j.1755-6724.2010.00258.x", "title": "Review of the El Soplao Amber Outcrop, Early Cretaceous of Cantabria, Spain", "abstract": "El Soplao outcrop, an Early Cretaceous amber deposit recently discovered in northern Spain (Cantabria), has been shown to be the largest site of amber with arthropod inclusions that has been found in Spain so far. Relevant data provided herein for biogeochemistry of the amber, palynology, taphonomy and arthropod bioinclusions complement those previously published. This set of data suggests at least two botanical sources for the amber of El Soplao deposit. The \u00f1rst (type A amber) strongly supports a source related to Cheirolepidiaceae, and the second (type B amber) shows non\u2010specific conifer biomarkers. Comparison of molecular composition of type A amber with Frenelopsis leaves (Cheirolepidiaceae) strongly suggests a biochemical affinity and a common botanical origin. A preliminary palynologlcal study indicates a regional high taxonomical diversity, mainly of pteridophyte spores and gymnosperm pollen grains. According to the preliminary palynologlcal data, the region was inhabited by conifer forests adapted to a dry season under a subtropical climate. The abundant charcoalified wood associated with the amber in the same beds is evidence of paleofires that most likely promoted both the resin production and an intensive erosion of the litter, and subsequent great accumulation of amber plus plant cuticles. In addition, for the first time in the fossil record, charcoalified plant fibers as bioinclusions in amber are reported. Other relevant taphonomic data are the exceptional presence of serpulids and bryozoans on the surfaces of some amber pieces indicating both a long exposure on marine or brackish\u2010water and a mixed assemblage of amber. Lastly, new findings of insect bioinclusions, some of them uncommon in the fossil record or showing remarkable adaptations, are reported. In conclusion, a documented scenario for the origin of the El Soplao amber outcrop is provided.", "keyphrases": ["cantabria", "spain", "bioinclusion"]}
{"id": "paleo.001190", "title": "TEASING FOSSILS OUT OF SHALES WITH CAMERAS AND COMPUTERS", "abstract": "Simple yet effective methods are available to enhance photographic images of low-contrast and lowrelief specimens, such as fossils in shales, without manipulating or retouching the photographs. By applying polarizing filters to camera and light-source(s) in a way analogous to crossing nicols in a petrographic microscope, dramatic results can be achieved where there is a difference in reflectance between fossil and matrix, as with many coalified fossils. For example, this method is ideal for bringing out the shiny films representing soft tissues of Middle Cambrian Burgess Shale fossils. It is also useful in reducing reflections and increasing contrast in specimens that cannot be immersed in liquid (e.g., the Lower Cambrian Chengjiang fauna). Plants and graptolites in shales are other examples of suitable objects for this method. In addition, the use of digital imaging now makes it very easy to use interference between two versions to bring out differences. In this way, images of the same object taken with and without crossed nicols can be contrasted, as well as different colour channels. The result may be a dramatic improvement in the definition of hard-to-see or hard-to-image structures.", "keyphrases": ["photograph", "filter", "burgess shale fossil", "liquid", "polarised light"]}
{"id": "10.1017/s0022336000036076", "title": "Neural spine elongation in dinosaurs: sailbacks or buffalo-backs?", "abstract": "Several dinosaurs, notably Ouranosaurus and Spinosaurus, have vertebral columns marked by prominent arrays of elongated neural spines. Using pelycosaurian sailbacks like Dimetrodon as analogies, popular orthodoxy holds that the tall spines served as supporting struts for dorsal sails of purported thermoregulatory function, especially heat dissipation in tropical climates. It is argued here that the neural spines of Ouranosaurus, Spinosaurus, and several other long-spined dinosaurs favor bison-like humps rather than sails: 1) in functional morphology and relative elongation they are dissimilar to pelycosaur spines but homoplastically converge on the spines of high-withered ungulates; 2) the usefulness of a sail in thermoregulation has been exaggerated\u2014in large tetrapods it would have been fairly efficient as a thermal amplifier but ineffective as a radiator; hence large sail-bearing dinosaurs in open tropical climates are improbable; 3) the insulation properties of humps favor gigantothermy, the most likely thermobiological model for large dinosaurs. Dinosaur humps are probable adaptations for: 1) energy storage, maintenance of gigantothermy, and heat-shielding in unshaded habitats; 2) long-distance migration from feeding to nesting grounds across terrains of variable productivity; and 3) lipid conservation for production of large clutches of eggs at the nesting site. Because sacral, caudal, or dorsal humps were relatively common traits among certain groups, the fashionably anorexic image of many large dinosaurs must be emended.", "keyphrases": ["elongation", "sailback", "thermoregulation", "neural spine"]}
{"id": "10.1073/pnas.1320156111", "title": "Effect of a Jurassic oceanic anoxic event on belemnite ecology and evolution", "abstract": "Significance The Toarcian oceanic anoxic event (OAE; \u223c183 million y ago) is marked by one of the largest carbon cycle perturbations in Earth history, rapid climate change, widespread ocean oxygen deficiency, and strong changes in marine ecosystems. The temporal links between increasing atmospheric pCO2, changes in ocean oxygen availability, and marine biotic response during this event are still poorly understood. Here we use isotopic analyses of calcite and organic matter from belemnites, marine predators of that time, to address their response to bottom water anoxia during the OAE. We infer that some belemnite taxa showed resilience to a strong reduction in ocean oxygen availability and occupied ecological niches in the Cleveland Basin (United Kingdom), enabling a strong evolutionary diversification after the event. The Toarcian oceanic anoxic event (T-OAE; \u223c183 million y ago) is possibly the most extreme episode of widespread ocean oxygen deficiency in the Phanerozoic, coinciding with rapid atmospheric pCO2 increase and significant loss of biodiversity in marine faunas. The event is a unique past tipping point in the Earth system, where rapid and massive release of isotopically light carbon led to a major perturbation in the global carbon cycle as recorded in organic and inorganic C isotope records. Modern marine ecosystems are projected to experience major loss in biodiversity in response to enhanced ocean anoxia driven by anthropogenic release of greenhouse gases. Potential consequences of this anthropogenic forcing can be approximated by studying analog environmental perturbations in the past such as the T-OAE. Here we present to our knowledge the first organic carbon isotope record derived from the organic matrix in the calcite rostra of early Toarcian belemnites. We combine both organic and calcite carbon isotope analyses of individual specimens of these marine predators to obtain a refined reconstruction of the early Toarcian global exogenic carbon cycle perturbation and belemnite paleoecology. The organic carbon isotope data combined with measurements of oxygen isotope values from the same specimens allow for a more robust interpretation of the interplay between the global carbon cycle perturbation, environmental change, and biotic response during the T-OAE. We infer that belemnites adapted to environmental change by shifting their habitat from cold bottom waters to warm surface waters in response to expanded seafloor anoxia.", "keyphrases": ["oceanic anoxic event", "organic matter", "belemnite taxa"]}
{"id": "paleo.011104", "title": "Floral Assemblages and Patterns of Insect Herbivory during the Permian to Triassic of Northeastern Italy", "abstract": "To discern the effect of the end-Permian (P-Tr) ecological crisis on land, interactions between plants and their insect herbivores were examined for four time intervals containing ten major floras from the Dolomites of northeastern Italy during a Permian\u2013Triassic interval. These floras are: (i) the Kungurian Tregiovo Flora; (ii) the Wuchiapingian Bletterbach Flora; (iii) three Anisian floras; and (iv) five Ladinian floras. Derived plant\u2013insect interactional data is based on 4242 plant specimens (1995 Permian, 2247 Triassic) allocated to 86 fossil taxa (32 Permian, 56 Triassic), representing lycophytes, sphenophytes, pteridophytes, pteridosperms, ginkgophytes, cycadophytes and coniferophytes from 37 million-year interval (23 m.yr. Permian, 14 m.yr. Triassic). Major Kungurian herbivorized plants were unaffiliated taxa and pteridosperms; later during the Wuchiapingian cycadophytes were predominantly consumed. For the Anisian, pteridosperms and cycadophytes were preferentially consumed, and subordinately pteridophytes, lycophytes and conifers. Ladinian herbivores overwhelming targeted pteridosperms and subordinately cycadophytes and conifers. Throughout the interval the percentage of insect-damaged leaves in bulk floras, as a proportion of total leaves examined, varied from 3.6% for the Kungurian (N = 464 leaves), 1.95% for the Wuchiapingian (N = 1531), 11.65% for the pooled Anisian (N = 1324), to 10.72% for the pooled Ladinian (N = 923), documenting an overall herbivory rise. The percentage of generalized consumption, equivalent to external foliage feeding, consistently exceeded the level of specialized consumption from internal feeding. Generalized damage ranged from 73.6% (Kungurian) of all feeding damage, to 79% (Wuchiapingian), 65.5% (pooled Anisian) and 73.2% (pooled Ladinian). Generalized-to-specialized ratios show minimal change through the interval, although herbivore component community structure (herbivore species feeding on a single plant-host species) increasingly was partitioned from Wuchiapingian to Ladinian. The Paleozoic plant with the richest herbivore component community, the coniferophyte Pseudovoltzia liebeana, harbored four damage types (DTs), whereas its Triassic parallel, the pteridosperm Scytophyllum bergeri housed 11 DTs, almost four times that of P. liebeana. Although generalized DTs of P. liebeana were similar to S. bergeri, there was expansion of Triassic specialized feeding types, including leaf mining. Permian\u2013Triassic generalized herbivory remained relatively constant, but specialized herbivores more finely partitioned plant-host tissues via new feeding modes, especially in the Anisian. Insect-damaged leaf percentages for Dolomites Kungurian and Wuchiapingian floras were similar to those of lower Permian, north-central Texas, but only one-third that of southeastern Brazil. Global herbivore patterns for Early Triassic plant\u2013insect interactions remain unknown.", "keyphrases": ["herbivory", "triassic", "northeastern italy"]}
{"id": "10.1671/039.029.0223", "title": "New Data on the Moschidae (Mammalia, Ruminantia) from the Upper Miocene of Spain (MN 10- MN 11)", "abstract": "ABSTRACT \n New data on the last representatives of the Spanish Miocene Moschidae (Mammalia, Ruminantia) are presented and discussed. A new species of Micromeryx, Micromeryx soriae, is described on the basis of fossil material from the locality of La Roma-2 (upper Vallesian; MN 10, Teruel province, Spain, previously assigned to Micromeryx sp.), Batallones-1, and Batallones-10 (upper Vallesian; local zone J, MN 10, Madrid province, Spain). The new species is characterized by possessing relatively hypsodont lower molars of advanced morphology and a unique type of Palaeomeryx-fold. M. soriae gives insight to the last representatives of the genus, which achieved an overall lower molar morphology that mimics to certain degree that of Hispanomeryx. several characters of the upper molars of the Miocene moschids Micromeryx and Hispanomeryx are described that are useful for characterizing both genera. These characters are used to solve the taxonomic problems of PM-659, an upper molar from Puente Minero (MN 11, Teruel province, Spain) that represents one of the last survivors of the Moschidae in the Iberian Peninsula. The systematic utility of the upper molars of Hispanomeryx and Micromeryx is demonstrated, and the use of size as the only way to distinguish between the two genera is refuted. Finally, the study of the morphological characters of PM-659 clearly supports its generic change from Micromeryx sp. to Hispanomeryx sp., thus recording the presence of Hispanomeryx in the Iberian Peninsula as late as the lower Turolian.", "keyphrases": ["moschidae", "mammalia", "hispanomeryx", "evolutionary history"]}
{"id": "10.1111/j.1469-185X.2010.00162.x", "title": "Evolving between land and water: key questions on the emergence and history of the Hippopotamidae (Hippopotamoidea, Cetancodonta, Cetartiodactyla)", "abstract": "The fossil record of the Hippopotamidae can shed light on three major issues in mammalian evolution. First, as the Hippopotamidae are the extant sister group of Cetacea, gaining a better understanding of the origin of the Hippopotamidae and of their Paleogene ancestors will be instrumental in clarifying phylogenetic relationships within Cetartiodactyla. Unfortunately, the data relevant to hippopotamid origins have generally been ignored in phylogenetic analyses of cetartiodactyls. In order to obtain better resolution, future analyses should consider hypotheses of hippopotamid Paleogene relationships. Notably, an emergence of the Hippopotamidae from within anthracotheriids has received growing support, leading to reconciliation between genetic and morphological evidence for the clade Cetancodonta (Hippopotamidae + Cetacea). Secondly, full account needs to be taken of the Hippopotamidae when studying the impact of environmental change on faunal evolution. This group of semi\u2010aquatic large herbivores has a clear and distinct ecological role and a diverse and abundant fossil record, particularly in the African Neogene. We examine three major phases of hippopotamid evolution, namely the sudden appearance of hippopotamines in the late Miocene (the \u201cHippopotamine Event\u201d), the subsequent rampant endemism in African basins, and the Pleistocene expansion of Hippopotamus. Each may have been influenced by multiple factors, including: late Miocene grass expansion, African hydrographical network disruption, and a unique set of adaptations that allowed Hippopotamus to respond efficiently to early Pleistocene environmental change. Thirdly, the fossil record of the Hippopotamidae documents the independent emergence of adaptive character complexes in relation to semiaquatic habits and in response to insular isolation. The semiaquatic specializations of fossil hippopotamids are particularly useful in interpreting the functional morphology and ecology of other, extinct groups of large semiaquatic herbivores. Hippopotamids can also serve as models to elucidate the evolutionary dynamics of island mammals.", "keyphrases": ["emergence", "hippopotamidae", "cetartiodactyla", "phylogenetic relationship"]}
{"id": "10.1146/annurev-earth-040610-133431", "title": "The Paleocene-Eocene Thermal Maximum: A Perturbation of Carbon Cycle, Climate, and Biosphere with Implications for the Future", "abstract": "During the Paleocene-Eocene Thermal Maximum (PETM), \u223c56 Mya, thousands of petagrams of carbon were released into the ocean-atmosphere system with attendant changes in the carbon cycle, climate, ocean chem- istry, and marine and continental ecosystems. The period of carbon release is thought to have lasted <20 ka, the duration of the whole event was \u223c200 ka, and the global temperature increase was 5-8 \u25e6 C. Terrestrial and marine or- ganisms experienced large shifts in geographic ranges, rapid evolution, and changes in trophic ecology, but few groups suffered major extinctions with the exception of benthic foraminifera. The PETM provides valuable insights into the carbon cycle, climate system, and biotic responses to environmental change that are relevant to long-term future global changes.", "keyphrases": ["paleocene-eocene thermal maximum", "carbon cycle", "carbonate", "petm", "ecosystem"]}
{"id": "paleo.010781", "title": "Convergent Evidence of Eagle Talons Used by Late Neanderthals in Europe: A Further Assessment on Symbolism", "abstract": "To contribute to have a better understanding of the symbolic or not use of certain items by Neanderthals, this work presents new evidence of the deliberate removal of raptor claws occurred in Mediterranean Europe during the recent phases of the Mousterian. Rio Secco Cave in the north-east of Italy and Mandrin Cave in the Middle Rh\u00f4ne valley have recently produced two golden eagle pedal phalanges from contexts not younger than 49.1\u201348.0 ky cal BP at Rio Secco and dated around 50.0 ky cal BP at Mandrin. The bones show cut-marks located on the proximal end ascribable to the cutting of the tendons and the incision of the cortical organic tissues. Also supported by an experimental removal of large raptor claws, our reconstruction explains that the deliberate detachment occurred without damaging the claw, in a way comparable at a general level with other Mousterian contexts across Europe. After excluding that these specimens met the nutritional requirements for human subsistence, we discuss the possible implications these findings perform in our current knowledge of the European Middle Palaeolithic context.", "keyphrases": ["neanderthals", "europe", "cut-mark"]}
{"id": "10.1098/rspb.2009.0173", "title": "A new tarkadectine primate from the Eocene of Inner Mongolia, China: phylogenetic and biogeographic implications", "abstract": "Tarka and Tarkadectes are Middle Eocene mammals known only from the Rocky Mountains region of North America. Previous work has suggested that they are members of the Plagiomenidae, an extinct family often included in the order Dermoptera. Here we describe a new primate, Tarkops mckennai gen. et sp. nov., from the early Middle Eocene Irdinmanha Formation of Inner Mongolia, China. The new taxon is particularly similar to Tarka and Tarkadectes, but it also displays many features observed in omomyids. A phylogenetic analysis based on a data matrix including 59 taxa and 444 dental characters suggests that Tarkops, Tarka and Tarkadectes form a monophyletic group\u2014the Tarkadectinae\u2014that is nested within the omomyid clade. Within Omomyidae, tarkadectines appear to be closely related to Macrotarsius. Dermoptera, including extant and extinct flying lemurs and plagiomenids, is recognized as a clade nesting within the polyphyletic group of plesiadapiforms, therefore supporting the previous suggestion that the relationship between dermopterans and primates is as close as that between plesiadapiforms and primates. The distribution of tarkadectine primates on both sides of the Pacific Ocean basin suggests that palaeoenvironmental conditions appropriate to sustain primates occurred across a vast expanse of Asia and North America during the Middle Eocene.", "keyphrases": ["tarkadectine", "inner mongolia", "china"]}
{"id": "10.1126/science.aba1135", "title": "A parapithecid stem anthropoid of African origin in the Paleogene of South America", "abstract": "A South American anthropoid Although there are many primate lineages in the Old World, it is thought that the New World is home to just one group, the platyrrhine monkeys, which appear to have colonized the region during the Eocene. Seiffert et al. describe a new primate species on the basis of fossil molars found in the Peruvian Amazon that appears to belong to the Parapithecidae, a group of stem anthropoid primates best known from northern Africa (see the Perspective by Godinot). The fossils appear to be from a well-differentiated lineage, suggesting that this species had been evolving within South America for some time. It is likely that the ancestors of this new species arrived via a transatlantic rafting event when sea levels dropped at the Eocene\u2013Oligocene transition \u223c32 to 35 million years ago. Science, this issue p. 194; see also p. 136 Fossils of molars suggest the existence of a South American stem anthropoid primate. Phylogenetic evidence suggests that platyrrhine (or New World) monkeys and caviomorph rodents of the Western Hemisphere derive from source groups from the Eocene of Afro-Arabia, a landmass that was ~1500 to 2000 kilometers east of South America during the late Paleogene. Here, we report evidence for a third mammalian lineage of African origin in the Paleogene of South America\u2014a newly discovered genus and species of parapithecid anthropoid primate from Santa Rosa in Amazonian Per\u00fa. Bayesian clock\u2013based phylogenetic analysis nests this genus (Ucayalipithecus) deep within the otherwise Afro-Arabian clade Parapithecoidea and indicates that transatlantic rafting of the lineage leading to Ucayalipithecus likely took place between ~35 and ~32 million years ago, a dispersal window that includes the major worldwide drop in sea level that occurred near the Eocene-Oligocene boundary.", "keyphrases": ["african origin", "paleogene", "south america", "eocene", "afro-arabia"]}
{"id": "paleo.009773", "title": "A Review of Shamosuchus and Paralligator (Crocodyliformes, Neosuchia) from the Cretaceous of Asia", "abstract": "The crocodyliform Shamosuchus is known from numerous Late Cretaceous localities in southern and eastern Mongolia and fragmentary remains from Uzbekistan. Seven species of Shamosuchus have been named from six localities in Mongolia and three in Uzbekistan. Six species originally described as Paralligator were later referred to Shamosuchus. Only the type species, Shamosuchus djadochtaensis has been examined in detail. Many of the named species of Shamosuchus show striking similarity in size and cranial morphology but most are based on partial remains suggesting that the true species diversity is overestimated. A review of all species referred to Shamosuchus recognizes three valid taxa: Shamosuchus djadochtaensis, S. gradilifrons, and S. major. Shamosuchus sungaricus, S. borealis, and S. karakalpakensis are nomena dubia, whereas S. ancestralis, S. ulgicus, S. tersus, and S. ulanicus are junior subjective synonyms of S. gradilifrons. Phylogenetic analysis of 318 phenotypic characters recovers a Paralligatoridae clade consisting of Shamosuchus, Rugosuchus, Batrachomimus, Glen Rose Form, and Wannchampsus. Shamosuchus is non-monophyletic: S. djadochtaensis is near the base of Paralligatoridae whereas S. gradilifrons + S. major are the most deeply nested. The name Paralligator is resurrected for this clade. Rugosuchus and Batrachomimus are sister taxa to Paralligator. Paralligatoridae is closely related to Theriosuchus, hylaeochampsids and a speciose Allodaposuchus clade, which together are the sister group of Borealosuchus plus Crocodylia. These results support the presence of a diverse clade in eastern Asia and western North America throughout the Cretaceous with origins in the Late Jurassic.", "keyphrases": ["shamosuchus", "paralligator", "cretaceous", "jurassic"]}
{"id": "10.7203/sjp.32.1.17033", "title": "Periostracum and fibrous shell microstructure in the unusual Cambrian hyolith Cupitheca", "abstract": "Cupitheca is an enigmatic tubular fossil common in early Cambrian deposits worldwide. It has recently been argued to be a hyolith, probably orthothecid. Cupitheca had a dense network of mantle-filled tubules that connected to what we interpret as a continuous organic periostracum. The innermost shell layer consists of horizontal or slightly inclined bundles of fibres elongated along the a-axis and offset from other bundles at aragonitic twin angles, confirming aragonite as the original mineralogy for the shell of Cupitheca. This is a similar Shell microstructure to that inferred for Cambrian hyoliths, strengthening the claim that Cupitheca is a hyolith. This shell microstructure of bundled aragonite fibres and the tubule systems can also be seen in many Cambrian molluscs and other lophotrochozoans. In some lineages this shell texture evolved into fracture-resistant crossed lamellar microstructure and in others nacre. These transitions began to occur sometime between the mid-Cambrian and Ordovician, and nacre and crossed lamellar microstructure were the most common constituents of the inner shell layer of molluscs by the middle or late Palaeozoic Era.", "keyphrases": ["shell microstructure", "cupitheca", "tubule", "periostracum"]}
{"id": "10.1130/G38498.1", "title": "The overlooked human influence in historic and prehistoric floods in the European Alps", "abstract": "Understanding the role of climate and humans in generating mountain slope instability is crucial because such instability influences downstream fluvial activity and is a major threat to societies. Here, we use the sedimentary archive of Lake Allos (southeastern France), a mountain lake in the European Alps, to characterize mountain flood deposits and vegetation dynamics over the past 7000 yr. Our results support the interpretation of a critical threshold in catchment sensitivity to erosion at 1700 calibrated (cal.) yr B.P. (A.D. 250) probably resulting from long-term, uninterrupted impacts of human activity. The frequency and severity of floods increased dramatically after this date. These results demonstrate that underestimation of human impacts over the Holocene may pose a challenge to a clear understanding of past climate changes because paleoflood records are highly likely to have been affected by geomorphic thresholds. Natural reforestation since the end of the 19th century does not appear to be sufficient to induce a flood regime comparable to that which occurred prior to 1700 cal. yr B.P. This poses the question as to whether forest restoration in high-altitude environments is liable to foster a return to a low-erosion regime over the next decades, or whether the overall severity of soil degradation has been such as to preclude a return to previous conditions.", "keyphrases": ["flood", "european alps", "human activity"]}
{"id": "10.1127/homo/2020/1063", "title": "Cone-Beam Computed Tomography vs. Multi-Slice Computed Tomography in paleoimaging: where we stand.", "abstract": "Paleopathology and anthropology are fields of research which have benefited from the use of diagnostic imaging since its introduction in the clinical setting. The deriving discipline, that is, paleoimaging, has effectively employed several diagnostic techniques. However, while Multi-Slice Computed Tomography (MSCT) has found its role in paleoimaging, Cone-Beam Computed Tomography (CBCT), despite its several advantages with regard to MSCT, is still struggling to find a clear position in this field. The aim of our study is to evaluate the possible advantages CBCT could bring to paleoimaging. We describe the characteristics and role of CBCT in clinical applications, in forensic and legal medicine, and in paleopathology. We report the study of an ancient mandible by means of CBCT and MSCT, in order to compare the quality of the images in terms of spatial resolution. CBCT allows to obtain good quality images of mineralized tissues. Moreover, the possibility of imaging metallic manufacts makes the technique suitable for the study not only of bony remains, but also of museum and archaeological artifacts. Our study highlights the strengths of CBCT as a valid imaging technique for the study of ancient bone remains and manufacts. A revision of the current uses of CBCT is provided and gives insights into the possible role it can cover in bioarchaeological studies. Further evaluation is needed in terms of possible applications of this technique to paleopathology. We strongly encourage the use of CBCT in paleoimaging, and suggest a broader application of the technique to the study of archaeological samples.", "keyphrases": ["paleopathology", "medicine", "cone-beam computed tomography"]}
{"id": "10.2307/2845616", "title": "Area-cladograms of Circum-Mediterranean taxa in relation to Mediterranean palaeogeography", "abstract": "Biogeographic characteristics of nine taxon- area-cladograms of various Circum-Mediterranean terres- trial animal groups are compared. Correlation with palaeo- geographic reconstructions suggests Oligocene and especially Miocene diversification within these groups. The oldest faunal elements are found in the western part of the region which dates from well before the Miocene. Origin of younger lineages is considered linked with the Late Oligocene-Early Miocene formation of a landmass which separated Tethys and Paratethys. Major divergence is hypothesized to have been achieved by subsequent vicariant and distributional events throughout the Mediter- ranean during the Miocene. The palaeo-biogeographic cor- relation results in estimates of the ages of lineages for the newt genus Triturus which largely correspond to the esti- mates obtained from various biochemical and molecular studies.", "keyphrases": ["tethys", "paratethys", "several circum-mediterranean faunae", "neogene palaeogeography", "entomofauna"]}
{"id": "paleo.010149", "title": "Dinosaurian Soft Tissues Interpreted as Bacterial Biofilms", "abstract": "A scanning electron microscope survey was initiated to determine if the previously reported findings of \u201cdinosaurian soft tissues\u201d could be identified in situ within the bones. The results obtained allowed a reinterpretation of the formation and preservation of several types of these \u201ctissues\u201d and their content. Mineralized and non-mineralized coatings were found extensively in the porous trabecular bone of a variety of dinosaur and mammal species across time. They represent bacterial biofilms common throughout nature. Biofilms form endocasts and once dissolved out of the bone, mimic real blood vessels and osteocytes. Bridged trails observed in biofilms indicate that a previously viscous film was populated with swimming bacteria. Carbon dating of the film points to its relatively modern origin. A comparison of infrared spectra of modern biofilms with modern collagen and fossil bone coatings suggests that modern biofilms share a closer molecular make-up than modern collagen to the coatings from fossil bones. Blood cell size iron-oxygen spheres found in the vessels were identified as an oxidized form of formerly pyritic framboids. Our observations appeal to a more conservative explanation for the structures found preserved in fossil bone.", "keyphrases": ["bacterial biofilm", "blood vessel", "fossil bone"]}
{"id": "10.1080/14772019.2017.1313323", "title": "Discovery of the oldest Gobius (Teleostei, Gobiiformes) from a marine ecosystem of Early Miocene age", "abstract": "Gobiidae (Gobiiformes, Teleostei) is among the largest families of vertebrates. These fishes are distributed worldwide and contribute significantly to species diversity in marine habitats and reefs. However, their fossil record is sparse prior to the Miocene and little is known about the course of diversification of the clade. Here we report exceptionally well-preserved skeletal remains of the oldest known Gobius from an Early Miocene (Burdigalian) marine ecosystem of Central Europe (Czech Republic). Gobius jarosi P\u0159ikryl & Reichenbacher sp. nov. is dated to 19.1\u201320.4 Ma by biostratigraphical analysis of calcareous nannoplankton from small fragments of the holotype matrix. Gobius jarosi sp. nov. is characterized by a pterygiophore formula of 3-22110 and a premaxilla with a distinctive postmaxillary process, has 11 abdominal and 16\u201317 caudal vertebrae, six thin spines in the first dorsal fin and one spine and 12 soft rays in the second dorsal fin, one spine and 11 rays in the anal fin, and two anal fin pterygiophores preceding the first haemal spine. Large ctenoid scales cover the body except for its anterior portion and the head. A comparative analysis of meristic and osteological data suggests close affinities between G. jarosi sp. nov. and the extant species G. niger, G. roulei and G. vittatus. Accompanying fish fossils and nannoplankton assemblages indicate that G. jarosi sp. nov., like G. roulei and G. vittatus, lived in an inshore to offshore marine ecosystem. The discovery of such an early member of the lineage leading to the present-day species of Gobius has important implications for the origin and evolution of the Gobiidae, and indicates that diversification of the European Gobiidae began in, but not before, the Early Miocene. http://zoobank.org/urn:lsid:zoobank.org:pub:3229739B-3428-4DFB-9588-4CE875D732D8", "keyphrases": ["gobiiformes", "marine ecosystem", "diversification", "gobioid"]}
{"id": "paleo.008847", "title": "Silurian retiolitid graptolites: Morphology and evolution", "abstract": "Developmental mode and proximal structures are commonly accepted as the best for the recognition of high-level taxonomic categories within the Graptoloidea. The petalolithids and retiolitids are unique in possessing a virgellar ancora and in the latter, distal ancora development. The ancora structures are considered homologous, and the ancorate petalolithids are considered to be the direct ancestors to the retiolitids. The Retiolitidae are unique among the diplograptoids in possessing (1) outer, lateral, ancora sleeve walls (derived from distal extension of the ancora), and (2) a skeletal framework of bandaged lists between which are a succession of very thin and rarely preserved fusellar layers. Retiolitids possess different kinds of thecal profiles and two types of micro-ornamentation on the lists, and these have served to distinguish between the subfamilies Retiolitinae and Plectograptinae. Complete retiolitid morphological terminology is clarified and explained. Cladistic analysis of the retiolitids provides some measure of a better understanding of retiolitid evolution, but adds only modest support for the retention of the two subfamily categories.", "keyphrases": ["ancora", "list", "holoretiolites", "rotaretiolites", "early taxa"]}
{"id": "10.1163/15685403-00003289", "title": "Family level classification within Thylacocephala, with comments on their evolution and possible relationships", "abstract": "Thylacocephala are among the most problematic of arthropod fossils. Various authors have allied them with all manner of crustacean groups, including branchiopods, cirripedes, remipedes, and malacostracans. They have a very apomorphic body plan often marked by hypertrophy of the compound eyes, three pairs of large raptorial subchelate limbs, eight sets of well-developed phyllobranch gills, and from 8 to at least 16 posterior trunk somites bearing paddle-like limbs. They have been thought of as a distinct class composed of two orders, Concavicarida and Conchyliocarida, but membership within the orders varies according to authors, and no familial divisions have been proposed within the orders until now. This lack of taxonomic structure inhibits organization of available information concerning the paleoecology, paleogeography, and phylogenetic relationships of thylacocephalans. A working hypothesis for the higher taxonomy within the class is proposed here. This entails a redefinition of the two orders, and recognition of seven families, five of them new: Austriocarididae Glaessner, 1931, Clausocarididae Arduini, 1992 (new status), Concavicarididae n. fam., Dollocarididae, n. fam., Microcarididae n. fam., Ostenocarididae n. fam. and Protozoeidae n. fam.", "keyphrases": ["thylacocephala", "compound eye", "appendage"]}
{"id": "10.5479/si.00810266.59.1", "title": "Two new Oligocene desmostylians and a discussion of tethytherian systematics", "abstract": "Domning, Daryl P., Clayton E. Ray, and Malcolm C. McKenna. Two New Oligocene Desmostylians and a Discussion of Tethytherian Systematics. Smithsonian Contributions to Paleobiology, number 59, 56 pages, 23 figures, 1986.\u2014 A new genus, comprising two new species of desmostylians, is described from marine Oligocene deposits of the Pacific Northwest. Behemotops proteus, new genus, new species, is based on an immature mandibular ramus and apparently associated skeletal fragments from the middle or (more likely) upper Oligocene lower part of the Pysht Formation of Clallam County, Washington. A related new species, Behemotops emlongi, is founded on a mandibular ramus of an old individual and a mandibular fragment with canine tusk from the uppermost Oligocene (early Arikareean equivalent) Yaquina Formation of Lincoln County, Oregon. The two new species are the most primitive known desmostylians and compare favorably with the primitive Eocene proboscideans Anthracobune and Moeritherium, and to the still more primitive tethythere Minchenella from the Paleocene of China. For many years the Desmostylia were widely regarded as members of the mammalian order Sirenia before being accepted as a taxon coordinate with the Sirenia and Proboscidea (Reinhart, 1953). On the basis of cladistic analysis we go a step further and regard the Desmostylia as more closely related to Proboscidea than to Sirenia because the Desmostylia and Proboscidea are interpreted herein to share a more recent common ancestor than either order does with the Sirenia. This analysis also suggests that the common ancestor of the Proboscidea and Desmostylia (but not the Sirenia) had suppressed P5 and the original last molar. These characters may be convergent with some other mammals. The Superorder Tokotheria McKenna, 1975, was originally thought to be characterized by loss of both P5 and M3. However, because early sirenians do not show these losses, they may have occurred independently in the common ancestor of proboscideans and desmostylians and in various other tokotheres. The late Paleocene genus Minchenella Zhang, 1980, from China, is a suitable candidate to be the common ancestor of both the Desmostylia and the Proboscidea. It possesses a small entoconid II on M:<. The Eocene genus Lammidhania Gingerich, 1977, from Pakistan, and the late Paleocene and/ or early Eocene Chinese and Mongolian phenacolophids had not acquired an entoconid II on M^ but are otherwise similar to Minchenella and the anthracobunids. The Asiatic occurrence of phenacolophids, Lammidhania, Minchenella, and anthracobunids suggests an Asian origin for the Proboscidea and is in accord with the exclusively Pacific distribution of the Desmostylia. We believe that desmostylians were amphibious herbivores that fed on marine algae and angiosperms, and that at least the earlier taxa depended to a large extent on plants exposed in the intertidal zone. OFFICIAL PUBLICATION DATE i.s handstamped in a limited number of initial copies and is recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: The trilobite Phacops rana Green. Library of Congress Cataloging in Publication Data Domning, Daryl P. Two new Oligocene desmostylians and a discussion of tethytherian systematics. (Smithsonian contributions to paleobiology ; no. 59) Bibliography: p. Supt. of Docs, no.: SI 1.30:59 1. Behemotops proteus. 2. Beheniotopsemlongi. 3. Desmostylia. 4. Proboscidea, Fossil. 5. Paleontology\u2014Oligocene. 6. Paleontology\u2014Washington(State)\u2014Clallam County. 7. Paleontology\u2014Oregon\u2014Lincoln County. 1. Ray, Clayton Edward. II. McKenna Malcolm C. 111. Title. IV. Series. QE701.S56no. 59 [QE882.D45J 560 s [569'.6] 85-600322", "keyphrases": ["new oligocene desmostylian", "tethytherian systematic", "desmostylia", "other mammal"]}
{"id": "paleo.003648", "title": "The latitudinal diversity gradient of tetrapods across the Permo-Triassic mass extinction and recovery interval", "abstract": "The decline in species richness from the equator to the poles is referred to as the latitudinal diversity gradient (LDG). Higher equatorial diversity has been recognized for over 200 years, but the consistency of this pattern in deep time remains uncertain. Examination of spatial biodiversity patterns in the past across different global climate regimes and continental configurations can reveal how LDGs have varied over Earth history and potentially differentiate between suggested causal mechanisms. The Late Permian\u2013Middle Triassic represents an ideal time interval for study, because it is characterized by large-scale volcanic episodes, extreme greenhouse temperatures and the most severe mass extinction event in Earth history. We examined terrestrial and marine tetrapod spatial biodiversity patterns using a database of global tetrapod occurrences. Terrestrial tetrapods exhibit a bimodal richness distribution throughout the Late Permian\u2013Middle Triassic, with peaks in the northern low latitudes and southern mid-latitudes around 20\u201340\u00b0 N and 60\u00b0 S, respectively. Marine reptile fossils are known almost exclusively from the Northern Hemisphere in the Early and Middle Triassic, with highest diversity around 20\u00b0 N. Reconstructed terrestrial LDGs contrast strongly with the generally unimodal gradients of today, potentially reflecting high global temperatures and prevailing Pangaean super-monsoonal climate system during the Permo-Triassic.", "keyphrases": ["latitudinal diversity gradient", "tetrapod", "equator", "low latitude"]}
{"id": "10.1098/rspb.2006.0443", "title": "First trace and body fossil evidence of a burrowing, denning dinosaur", "abstract": "A fossil discovery in the mid-Cretaceous Blackleaf Formation of southwest Montana, USA, has yielded the first trace and body fossil evidence of burrowing behaviour in a dinosaur. Skeletal remains of an adult and two juveniles of Oryctodromeus cubicularis gen. et sp. nov., a new species of hypsilophodont-grade dinosaur, were found in the expanded distal chamber of a sediment-filled burrow. Correspondence between burrow and adult dimensions supports Oryctodromeus as the burrow maker. Additionally, Oryctodromeus exhibits features of the snout, shoulder girdle and pelvis consistent with digging habits while retaining cursorial hindlimb proportions. Association of adult and young within a terminal chamber provides definitive evidence of extensive parental care in the Dinosauria. As with modern vertebrate cursors that dig, burrowing in Oryctodromeus may have been an important adaptation for the rearing of young. Burrowing also represents a mechanism by which small dinosaurs may have exploited the extreme environments of polar latitudes, deserts and high mountain areas. The ability among dinosaurs to find or make shelter may contradict some scenarios of the Cretaceous\u2013Paleogene impact event. Burrowing habits expand the known range of nonavian dinosaur behaviours and suggest that the cursorial ancestry of dinosaurs did not fully preclude the evolution of different functional regimes, such as fossoriality.", "keyphrases": ["body fossil evidence", "burrowing", "usa", "behaviour", "first trace"]}
{"id": "10.1130/G21053.1", "title": "Timing of Early Cretaceous angiosperm diversification and possible links to major paleoenvironmental change", "abstract": "Palynological records from the Western Portuguese and Algarve basins (Portugal) provide new insights on the timing and pattern of the early diversification of angiosperms (flowering plants) and its relationship to global environmental perturbations during the late Early Cretaceous. Angiosperm pollen displays a stepwise increase in both diversity and relative abundance during the late Barremian to middle Albian interval (ca. 124\u2013104 Ma), reflecting the incipient radiation of flowering plants in lower midlatitude floras. Our results provide new evidence for the age interpretation of the previously described angiosperm mesofossil floras and associated in situ pollen assemblages from the Western Portuguese basin, until now interpreted as Barremian or possibly Aptian in age. Biostratigraphic and sedimentologic evidence indicates a post-Aptian age for these assemblages, hence demonstrating a major radiation phase of angiosperms during the early Albian. Correlation of the angiosperm pollen record with data on global paleoenvironmental changes suggests a link between the rapid adaptive radiation of flowering plants and major climatic and oceanographic perturbations during the late Early Cretaceous.", "keyphrases": ["diversification", "link", "paleoenvironmental change"]}
{"id": "10.1080/02724634.2017.1410483", "title": "New Varanid Remains from the Miocene (MN4\u2013MN5) of France: Inferring Fossil Lizard Phylogeny from Subsets of Large Morphological Data Sets", "abstract": "ABSTRACT \n Fossil vertebrae from the early Miocene of France (Loire Basin) are described. They show several characters generally regarded as varanid synapomorphies. A phylogenetic analysis of these vertebrae is performed with a subset of morphological data taken from several large morphological data sets (vertebral characters) and it confirms an attribution to varanid lizards. Moreover, referral of isolated vertebrae from the Eocene-Oligocene of Egypt to varanids is confirmed. The use of subsets of large morphological data sets in phylogenetic analysis of fossils (especially incomplete remains) is discussed and advocated for, and we argue that convergence between tree topologies obtained from different kinds of data sets is a key issue in inferring the phylogenetic position of fossil taxa.", "keyphrases": ["miocene", "france", "vertebral character", "fossil taxa"]}
{"id": "10.1111/j.1469-7580.2008.00863.x", "title": "Fins into Limbs - Edited by B. K. Hall", "abstract": "For those of us whose careers in developmental biology stretch back a long way, the most exciting insights in the last forty years have, without doubt, been in the area of evolutional developmental biology, or evo-devo. The story has a history. Erasmus Darwin and others at the end of the 18th century advanced the possibility of evolution and in 1859, Charles Darwin published the core mechanism in The Origin of Species. He was, however, very thin on the relationship between evolution and embryology and was not always right, for example: \u2018From what we know of the embryos of mammals, birds, fishes and vertebrates, these animals are the modified descendents of some ancient progenitor, which was furnished in its adult state with branchiae, a swim-bladder, four fish-like limbs, and a long tail, all fitted for aquatic life\u2019. Haeckel, the major comparative anatomist at the end of the 19th century, got it wrong with his biogenetic law, which essentially states that evolution adds to, rather than modifies, embryonic development. \n \nIt seems to have been Waddington, harking back to von Baer, who was the first person to emphasize that the roots of anatomical variation lay in mutations that affected development. At a more practical level, a great deal of anatomical and palaeontological data on the relationships between development and evolution has been collected during the last two centuries. It was not until the early 1980s, however, with the rise of eukaryotic molecular genetics and the recognition that hox patterning underpinned so much of axial organization across the Bilateria, that the field could start to put molecular flesh on the bare bones of the earlier theoretical and anatomical insights. \n \nFrom these beginnings, the results of a lot of hard work over the last 25 years linking molecular biology, palaeontology, bioinformatics, evolutional homologies and experimental embryology have been that we now understand something of the molecular details of the development and evolution of biological structure. Nowhere, however, have the successes been as great as in the evolution of fins into limbs, a homology that first seems to have been pointed out by Carl Gegenbaur in 1865 and most recently analysed in Jenny Clack's monograph Gaining Ground. \n \nThe publication of the multi-authored Fins into Limbs carries on where Gaining Ground ended: its three sections and 19 chapters explore almost every aspect of limb evolution and development. The first section discusses evolutional history, skeletal changes in the fin-to-limb transition (obviously written before the publication of Tiktaalik roseae), locomotion and evolutional novelties. The eight chapters on development (the only section with molecular data) cover everything in the area from patterning mechanisms to postnatal growth to regeneration. The last section on transformation has seven chapters that review the evolution of the amphibian and mammalian appendicular skeletons, sesamoids and ossicles, limb diversity, and adaptations for flying, digging and swimming. \n \nLet me not beat about the bush: I think Fins into Limbs is the best and most enjoyable multi-author book that I have come across in years. It will be a standard in the field for some time and anyone with the slightest interest in evo-devo, as well as anyone with even a passing interest in fins and/or limbs, should read it. Why am I so enthusiastic? There are several reasons and the first is the general high scientific quality of the chapters, several of which contain important reference material. The second is the way that the chapters cohere to give such a rich picture of a fascinating area, building on their historical roots where appropriate while being, so far as I can see, pretty well up to date. The third is the way that knowledge in so many areas of science is brought together to illuminate one or another aspect of the story \u2013 it is a very modern book. For all this, much credit goes of course to the editor, but to use the quote from William Harvey that Joseph Needham cites in the dedication of his wonderful book A History of Embryology, \u2018all did well\u2019. Actually there is a different sort of reason for being so uncritical: if something is enjoyable to read, it disarms the critical instincts of the reader, and I felt disarmed! \n \nMany of the chapters are of general interest (evolution, development), although this may just mean that I had the appropriate background to read them without the need to run to my reference books and wikis. Some seemed to me to be more specialized (almost anything to do with the anatomical details of adaptation was new to me) but I enjoyed finding out about some wonderful obscurities: there are, for example, more than 20 sesamoids and inconstant ossicles in the human foot, the first time-lapse study of aquatic motion was first carried out by Marey in 1890 on a tethered skate (the pictures were good!), and there are four types and three grades of joints \u2013 a challenge to those who investigate molecular pathways and systems. \n \nGiven that so much is good in this book, it may seem ungenerous for a reviewer to think about the next edition and what it will contain, but, with the intention of encouraging it, I will. It is hard to think that there is much more to be said on the anatomical side but I did come away with the feeling that our knowledge of the molecular underpinnings of limb development is still rudimentary. On the basis of expression and transgenic studies, we know the roles of many genes involved in limb development and understand the basics of the networks in which they participate, but there is a large gap between our knowledge of the regulatory pathways and the anatomical structures that they generate. Similarly, we have little insight into how mutation leads to the quantitative changes in pathway kinetics that, in turn, lead to the wide range of limb forms among vertebrates. It is not unreasonable to expect, in the near future, a great deal of research into the dynamics of the molecular events downstream of transcriptional activation and in pathway kinetics. \n \nIt is only in this area of computational biology that Fins into Limbs is thin. Network dynamics is one aspect where we can expect progress; modelling of mutation rates to changes in phenotype will be another and the linking of anatomical change to functional change will be a third. The considerable progress currently being made in the quantitative modelling of musculo-skeletal anatomy to predict running and jumping activity is allowing us to link changes in limb anatomy to changes in behaviour, and this in turn will increase our knowledge of how extinct animals lived and evolved. We can look forward to real progress being made in this area of biomechanics in the next few years, and incorporated into the next edition of Fins into Limbs\u2013 for now, it is enough to enjoy a very good and important book.", "keyphrases": ["limbs", "field", "appendicular skeleton", "biomechanic", "fin"]}
{"id": "paleo.010219", "title": "The RNA world and the origin of metabolic enzymes", "abstract": "An RNA world has been placed centre stage for explaining the origin of life. Indeed, RNA is the most plausible molecule able to form both a (self)-replicator and to inherit information, necessities for initiating genetics. However, in parallel with self-replication, the proto-organism had to obtain the ability to catalyse supply of its chemical constituents, including the ribonucleotide metabolites required to replicate RNA. Although the possibility of an RNA-catalysed metabolic network has been considered, it is to be questioned whether RNA molecules, at least on their own, possess the required catalytic capacities. An alternative scenario for the origin of metabolism involves chemical reactions that are based on environmental catalysts. Recently, we described a non-enzymatic glycolysis and pentose phosphate pathway-like reactions catalysed by metal ions [mainly Fe(II)] and phosphate, simple inorganic molecules abundantly found in Archaean sediments. While the RNA world can serve to explain the origin of genetics, the origin of the metabolic network might thus date back to constraints of environmental chemistry. Interestingly, considering a metal-catalysed origin of metabolism gives rise to an attractive hypothesis about how the first enzymes could have formed: simple RNA or (poly)peptide molecules could have bound the metal ions, and thus increased their solubility, concentration and accessibility. In a second step, this would have allowed substrate specificity to evolve.", "keyphrases": ["rna world", "enzyme", "reaction"]}
{"id": "10.4436/JASS.96004", "title": "Grotta del Cavallo (Apulia-Southern Italy). The Uluzzian in the mirror.", "abstract": "The Uluzzian techno-complex is commonly considered to be a \"transitional industry\" mostly on the basis of some inferred characteristics such as a chiefly flake-based production, a small amount of Upper Palaeolithic-like tools and a combination of Middle and Upper Palaeolithic elements both in the toolkit and in the technical systems. Following its discovery, the Uluzzian was identified as the Italian counterpart of the French Ch\u00e2telperronian and attributed to Neandertals. However, a study issued in 2011 has established the modern character of the two deciduous teeth found in 1964 in the Uluzzian deposit of Grotta del Cavallo, fostering renewed interests to the Uluzzian culture, which real nature is almost unknown to the international scientific community. Here we provide preliminary results of the study on the lithic assemblage from the earliest Uluzzian layer and on backed pieces from the whole Uluzzian sequence of Grotta del Cavallo (Apulia, Italy), the type site of the Uluzzian. Moreover, besides a thorough review on the stratigraphy of Grotta del Cavallo (Supplementary Materials), we provide updated information on the human remains by presenting two unpublished teeth from the reworked deposit of the same cave. We conclude that the early Uluzzians demonstrate original technological behavior and innovations devoid of any features deriving or directly linked with the late Mousterian of Southern Italy. Therefore, the novelty nature of the Uluzzian techno-complex (with respect to the preceding Mousterian) complies with the recent reassessment of the two deciduous teeth from Grotta del Cavallo in suggesting an earliest migration of modern humans in southern Europe around 45,000 years ago.", "keyphrases": ["italy", "uluzzian", "transitional industry", "industry"]}
{"id": "paleo.001995", "title": "Systematics and phylogeny of Vasseuromys (Mammalia, Rodentia, Gliridae) with a description of a new species from the late Miocene of eastern Europe", "abstract": "Vasseuromys is a species\u2010rich genus of small\u2010 to medium\u2010sized glirids spanning the latest Oligocene to late Miocene of Europe and western Asia. Despite extensive discoveries over the past 50 years, little phylogenetic work has been done on Vasseuromys. This study presents the first phylogenetic analysis of the genus that includes all the described species and a new taxon Vasseuromys tectus sp. nov. from the late Miocene of eastern Europe, providing the first insights into the evolutionary relationships within the clade. Results suggest that the genus is clearly paraphyletic. Two strongly supported genus\u2010level clades are recognized within \u2018Vasseuromys\u2019: a restricted Vasseuromys clade (containing the three species, V. pannonicus, V. rugosus and V. tectus) and the Glirulus clade that includes \u2018Vasseuromys\u2019 duplex. The remaining \u2018Vasseuromys\u2019 species are found to constitute a set of paraphyletic taxa, with the polyphyletic \u2018Ramys\u2019 nested within it. The genus Gliruloides is synonymized with Glirulus. Vasseuromys tectus sp. nov. is the most derived member of the genus in having a greater number of cheek teeth ridges including constantly present anterotrope, centrotrope, second prototrope on M1\u20132, third metatrope on M2, two to three posterotropids on p4 and strong ectolophids on lower molars. The results of the study confirm a European origin for Vasseuromys while suggesting that the late Miocene species of the genus dispersed from the east in the early Turolian.", "keyphrases": ["vasseuromys", "late miocene", "europe", "phylogenetic analysis"]}
{"id": "paleo.008143", "title": "Taxonomy of the proterosuchid archosauriforms (Diapsida: Archosauromorpha) from the earliest Triassic of South Africa, and implications for the early archosauriform radiation", "abstract": "Proterosuchidae is one of the first clades of Archosauriformes (archosaurs and closely related species) to appear in the fossil record, with the richest sample of the group coming from the Lystrosaurus Assemblage Zone (earliest Triassic) of South Africa. Four nominal proterosuchid species were described from South Africa during the twentieth century (Proterosuchus fergusi, Chasmatosaurus vanhoepeni, Chasmatosaurus alexanderi and Elaphrosuchus rubidgei), but interpretations of their taxonomy have been widely disparate. The most recent taxonomic revision concluded that P. fergusi is the only valid species and that the other nominal species are junior subjective synonyms of this taxon. This proposal was based on the interpretation that anatomical differences between the nominal species could be explained as a result of ontogenetic changes and/or post\u2010mortem deformation. The recent discoveries of multiple new South African proterosuchid specimens provide an impetus to revisit their taxonomy. Based upon a comprehensive re\u2010examination of all known specimens, as well as examination of other proterosuchid taxa in collections worldwide, we conclude that the holotype of Proterosuchus fergusi is undiagnostic. As a result, we propose a neotype (RC 846) for the species. \u2018Chasmatosaurus vanhoepeni\u2019 and \u2018Elaphrosuchus rubidgei\u2019 are considered subjective junior synonyms of P. fergusi. \u2018Chasmatosaurus\u2019 alexanderi is considered a valid species, for which we propose the new combination P. alexanderi comb. nov. A third species, P. goweri sp. nov., is erected on the basis of a single specimen (NMQR 880). All three species recognized here are taxonomically distinct from a previously described archosauriform maxilla from the lower Lystrosaurus AZ. As a result, we recognize a minimum of four archosauriform species following the Permo\u2010Triassic mass extinction in South Africa. Our results suggest a greater species richness of earliest Triassic archosauriforms than previously appreciated, but that archosauriform morphological disparity remained low and did not expand until the late Early Triassic \u2013 early Mid\u2010Triassic.", "keyphrases": ["proterosuchid specimen", "early triassic", "taxonomy"]}
{"id": "10.1093/sysbio/syy009", "title": "Testing the role of the Red Queen and Court Jester as drivers of the macroevolution of Apollo butterflies", "abstract": "In macroevolution, the Red Queen (RQ) model posits that biodiversity dynamics depend mainly on species-intrinsic biotic factors such as interactions among species or life-history traits, while the Court Jester (CJ) model states that extrinsic environmental abiotic factors have a stronger role. Until recently, a lack of relevant methodological approaches has prevented the unraveling of contributions from these two types of factors to the evolutionary history of a lineage. Here we take advantage of the rapid development of new macroevolution models that tie diversification rates to changes in paleoenvironmental (extrinsic) and/or biotic (intrinsic) factors. We inferred a robust and fully-sampled species-level phylogeny, as well as divergence times and ancestral geographic ranges, and related these to the radiation of Apollo butterflies (Parnassiinae) using both extant (molecular) and extinct (fossil/morphological) evidence. We tested whether their diversification dynamics are better explained by a RQ or CJ hypothesis, by assessing whether speciation and extinction were mediated by diversity-dependence (niche filling) and clade-dependent host-plant association (RQ) or by large-scale continuous changes in extrinsic factors such as climate or geology (CJ). For the RQ hypothesis, we found significant differences in speciation rates associated with different host-plants but detected no sign of diversity-dependence. For CJ, the role of Himalayan-Tibetan building was substantial for biogeography but not a driver of high speciation, while positive dependence between warm climate and speciation/extinction was supported by continuously varying maximum-likelihood models. We find that rather than a single factor, the joint effect of multiple factors (biogeography, species traits, environmental drivers, and mass extinction) is responsible for current diversity patterns, and that the same factor might act differently across clades, emphasizing the notion of opportunity. This study confirms the importance of the confluence of several factors rather than single explanations in modeling diversification within lineages.", "keyphrases": ["red queen", "court jester", "macroevolution", "abiotic factor", "diversification"]}
{"id": "10.1098/rsta.2012.0006", "title": "Long-term legacy of massive carbon input to the Earth system: Anthropocene versus Eocene", "abstract": "Over the next few centuries, with unabated emissions of anthropogenic carbon dioxide (CO2), a total of 5000\u2009Pg C may enter the atmosphere, causing CO2 concentrations to rise to approximately 2000\u2009ppmv, global temperature to warm by more than 8\u00b0C and surface ocean pH to decline by approximately 0.7 units. A carbon release of this magnitude is unprecedented during the past 56 million years\u2014and the outcome accordingly difficult to predict. In this regard, the geological record may provide foresight to how the Earth system will respond in the future. Here, we discuss the long-term legacy of massive carbon release into the Earth's surface reservoirs, comparing the Anthropocene with a past analogue, the Palaeocene\u2013Eocene Thermal Maximum (PETM, approx. 56\u2009Ma). We examine the natural processes and time scales of CO2 neutralization that determine the atmospheric lifetime of CO2 in response to carbon release. We compare the duration of carbon release during the Anthropocene versus PETM and the ensuing effects on ocean acidification and marine calcifying organisms. We also discuss the conundrum that the observed duration of the PETM appears to be much longer than predicted by models that use first-order assumptions. Finally, we comment on past and future mass extinctions and recovery times of biotic diversity.", "keyphrases": ["earth system", "anthropocene", "carbon release", "petm", "long-term legacy"]}
{"id": "10.1002/jmor.11036", "title": "Traits and evolution of wing venation pattern in paraneopteran insects", "abstract": "Two different patterns of wing venation are currently supposed to be present in each of the three orders of Paraneoptera. This is unlikely compared with the situation in other insects where only one pattern exists per order. We propose for all Paraneoptera a new and unique interpretation of wing venation pattern, assuming that the convex cubitus anterior gets fused with the common stem of median and radial veins at or very near to wing base, after separation from concave cubitus posterior, and re\u2010emerges more distally from R + M stem. Thereafter, the vein between concave cubitus posterior and CuA is a specialized crossvein called \u201ccua\u2010cup,\u201d proximally concave and distally convex. We show that despite some variations, that is, cua\u2010cup can vary from absent to hypertrophic; CuA can re\u2010emerge together with M or not, or even completely disappear, this new interpretation explains all situations among all fossil and recent paraneopteran lineages. We propose that the characters \u201cCuA fused in a common stem with R and M\u201dand \u201cpresence of specialized crossvein cua\u2010cup\u201d are venation apomorphies that support the monophyly of the Paraneoptera. In the light of these characters, we reinterpret several Palaeozoic and early Mesozoic fossils that were ascribed to Paraneoptera, and confirm the attribution of several to this superorder as well as possible attribution of Zygopsocidae (Zygopsocus permianus Tillyard, 1935) as oldest Psocodea. We discuss the situation in extinct Hypoperlida and Miomoptera, suggesting that both orders could well be polyphyletic, with taxa related to Archaeorthoptera, Paraneoptera, or even Holometabola. The Carboniferous Protoprosbolidae is resurrected and retransferred into the Paraneoptera. The genus Lithoscytina is restored. The miomopteran Eodelopterum priscum Schmidt, 1962 is newly revised and considered as a fern pinnule. In addition, the new paraneopteran Bruayaphis oudardi gen. nov. et sp. nov. is described fromthe Upper Carboniferous of France (see Supporting Information). J. Morphol., 2012. \u00a9 2011 Wiley Periodicals, Inc.", "keyphrases": ["wing venation pattern", "vein", "miomoptera"]}
{"id": "paleo.005318", "title": "Likelihood reinstates Archaeopteryx as a primitive bird", "abstract": "The widespread view that Archaeopteryx was a primitive (basal) bird has been recently challenged by a comprehensive phylogenetic analysis that placed Archaeopteryx with deinonychosaurian theropods. The new phylogeny suggested that typical bird flight (powered by the front limbs only) either evolved at least twice, or was lost/modified in some deinonychosaurs. However, this parsimony-based result was acknowledged to be weakly supported. Maximum-likelihood and related Bayesian methods applied to the same dataset yield a different and more orthodox result: Archaeopteryx is restored as a basal bird with bootstrap frequency of 73 per cent and posterior probability of 1. These results are consistent with a single origin of typical (forelimb-powered) bird flight. The Archaeopteryx\u2013deinonychosaur clade retrieved by parsimony is supported by more characters (which are on average more homoplasious), whereas the Archaeopteryx\u2013bird clade retrieved by likelihood-based methods is supported by fewer characters (but on average less homoplasious). Both positions for Archaeopteryx remain plausible, highlighting the hazy boundary between birds and advanced theropods. These results also suggest that likelihood-based methods (in addition to parsimony) can be useful in morphological phylogenetics.", "keyphrases": ["archaeopteryx", "phylogenetic analysis", "probability"]}
{"id": "paleo.005776", "title": "Fossil freshwater sponges: taxonomy, geographic distribution, and critical review", "abstract": "Sponges are one of the most ancient animal phyla with about 8850 living species and about 5000 described fossil taxa. Most sponges are marine and live at all depths of all oceans. Freshwater bodies (lakes, rivers) are inhabited only by a small minority of species, ca. 240 (< 3%) comprising the order Spongillida (Demospongiae) most of which are able to produce specialized resting bodies to survive harsh terrestrial environmental conditions. This highly disproportionate ratio of marine and freshwater sponges is even more accentuated in the field of palaeontology with rare records reported up to the Miocene (< 0.4% of all known fossil sponges). Only a few fossil taxa were correctly supported by strong and convincing taxonomic morphotraits at genus and species level, thus we provide here an overview of fossil freshwater sponges focusing on their morphotraits and distribution in time and space. Each recorded taxon is described in detail following the modern taxonomy and nomenclature. All fossil data suggest a clear trend of long term conservative morphology in the evolutionary history of Spongillida, although some traits of Recent gemmules evolved in a wide array of adaptive morpho-functional novelties. The majority of accepted fossil species belongs to the cosmopolitan family Spongillidae. The genera Oncosclera and Potamophloios of the family Potamolepidae seem to have had, in the past, a much larger geographic range than today. A synthesis of fossil taxa morphotraits is also provided in an Appendix 1.", "keyphrases": ["taxonomy", "fossil specie", "family spongillidae"]}
{"id": "10.1111/j.1475-4983.2010.00961.x", "title": "Pliensbachian gastropods from Venetian Southern Alps (Italy) and their palaeobiogeographical significance", "abstract": "Abstract:\u2002 The Pliensbachian gastropods described by De Toni in 1912, coming from an isolated boulder at the foot of Mt Vedana (eastern margin of Trento Platform, Venetian Southern Alps, Italy) are revised. The fauna consists of 13 species representing nine families and eight superfamilies. Despite the low number of species, the assemblage represents the most diverse Early Jurassic gastropod fauna known for the Venetian Southern Alps. The boulder yielding the material was thought to derive from the upper part of the Early Jurassic Calcari Grigi Group, a carbonate platform unit extensively cropping out in the Mt Vedana area. The sedimentological analysis indicates a prevalently bioclastic wackstone\u2010floatstone, reflecting a lime\u2010muddy deposit undergone to an early consolidation. This and the high content of ammonoids, which is unusual for the Calcari Grigi Group, are typical aspects of a condensed pelagic sediment, presumably a fissure filling at the top of the carbonate platform succession. Palaeobiogeographical comparisons show that the fauna is composed of species occurring exclusively in pelagic limestones of the western Tethys. By contrast, it shows no relationships with the coeval faunas of the adjacent Trento platform and of the other western Tethyan carbonate platforms. These lines of evidence and the facies analysis would testify to the Pliensbachian drowning of the eastern margin of the Trento platform. In the wider context of the palaeobiogeographical history of Early Jurassic western Tethyan gastropods, the species from Vedana belong to a faunal stock which is typical for pelagic, mainly postdrowning sediments. Thus, appearance and diffusion in space and time of this stock were probably regulated by the direction, rate and pattern of the Neotethyan rifting. A new subgenus, Proarcirsa (Schafbergia) subgen. nov., and three new species, namely Ataphrus (Ataphrus) cordevolensis sp. nov., Guidonia pseudorotula sp. nov. and Proarcirsa (Schafbergia) zirettoensis sp. nov. are erected.", "keyphrases": ["venetian southern alps", "western tethys", "neotethyan rifting", "pliensbachian gastropod"]}
{"id": "10.1144/jgs2020-043", "title": "Brachiopod-dominated communities and depositional environment of the Guanshan Konservat-Lagerst\u00e4tte, eastern Yunnan, China", "abstract": "The Guanshan Biota is an unusual early Cambrian Konservat-Lagerst\u00e4tte from China and is distinguished from all other exceptionally preserved Cambrian biotas by the dominance of brachiopods and a relatively shallow depositional environment. However, the faunal composition, overturn and sedimentology associated with the Guanshan Biota are poorly understood. This study, based on collections through the best-exposed succession of the basal Wulongqing Formation at the Shijiangjun section, Wuding County, eastern Yunnan, China recovered six major animal groups with soft tissue preservation; brachiopods vastly outnumbered all other groups. Brachiopods quickly replace arthropods as the dominant fauna following a transgression at the base of the Wulongqing Formation. A transition from a botsfordiid-, eoobolid- and acrotretid- to an acrotheloid-dominated brachiopod assemblage occurs up-section. Four episodically repeated lithofacies reveal a relatively low-energy, offshore to lower shoreface sedimentary environment at the Shijiangjun section, which is very different from the Wulongqing Formation in the Malong and Kunming areas. Multiple event flows and rapid obrution are responsible for faunal overturn and fluctuation through the section. A detailed lithofacies and palaeontological investigation of this section provides a better understanding of the processes and drivers of faunal overturn during the later phase of the Cambrian Explosion. Supplementary material: Composition and comparison of the Malong Fauna and the Guanshan Biota is are available at: https://doi.org/10.6084/m9.figshare.c.5080799", "keyphrases": ["depositional environment", "eastern yunnan", "biota"]}
{"id": "10.1029/92PA01651", "title": "A high\u2010resolution diatom record of the last deglaciation from the SE Norwegian Sea: Documentation of rapid climatic changes", "abstract": "Although the pulsating nature and the abruptness of the last deglaciation are well documented in marine and land records, very few marine records have so far been able to capture the high-frequency climatic changes recorded in the Greenland ice core Dye 3. We studied high-resolution sediment cores from SE Norwegian Sea, which display a detailed climatic record during the last deglaciation comparable to that of Dye 3. Accelerator mass spectrometry age control of the cores enables us to correlate this record in detail with continental records. The results indicate that the surface waters of the SE Norwegian Sea were seasonally ice free after 13,400 B.P. The Bolling/Allerod interstadial complex (13,200\u201311,200 B.P.) was a climatically unstable period with changing Arctic-Subarctic conditions. This period was punctuated by four progressively more severe sea surface temperature (SST) minima: between 12,900\u201312,800 B.P. (BCP I); 12,500\u201312,400 B.P. (BCP II); 12,300\u201312,000 B.P. (OD I); and 11,800\u201311,500 B.P. (OD II). The Younger Dryas (YD) (11,200\u201310,200 B.P.) represents the severest and most prolonged cold episode of this series of climatic deteriorations. It was bounded by very rapid SST changes and characterized by Arctic-Polar conditions. The first true warm Atlantic water incursion to the SE Norwegian Sea took place around 10,100 B.P., followed by a brief cooler condition between 9900\u20139600 B.P. (YD II). The early Holocene climatic optimum occurred between 8000\u20135000 B.P. A conceptual model is proposed where meltwater fluxes are suggested to cause the observed instability in the SST record.", "keyphrases": ["last deglaciation", "climatic change", "younger dryas"]}
{"id": "paleo.013014", "title": "Evolutionary History of Lagomorphs in Response to Global Environmental Change", "abstract": "Although species within Lagomorpha are derived from a common ancestor, the distribution range and body size of its two extant groups, ochotonids and leporids, are quite differentiated. It is unclear what has driven their disparate evolutionary history. In this study, we compile and update all fossil records of Lagomorpha for the first time, to trace the evolutionary processes and infer their evolutionary history using mitochondrial genes, body length and distribution of extant species. We also compare the forage selection of extant species, which offers an insight into their future prospects. The earliest lagomorphs originated in Asia and later diversified in different continents. Within ochotonids, more than 20 genera occupied the period from the early Miocene to middle Miocene, whereas most of them became extinct during the transition from the Miocene to Pliocene. The peak diversity of the leporids occurred during the Miocene to Pliocene transition, while their diversity dramatically decreased in the late Quaternary. Mantel tests identified a positive correlation between body length and phylogenetic distance of lagomorphs. The body length of extant ochotonids shows a normal distribution, while the body length of extant leporids displays a non-normal pattern. We also find that the forage selection of extant pikas features a strong preference for C3 plants, while for the diet of leporids, more than 16% of plant species are identified as C4 (31% species are from Poaceae). The ability of several leporid species to consume C4 plants is likely to result in their size increase and range expansion, most notably in Lepus. Expansion of C4 plants in the late Miocene, the so-called \u2018nature\u2019s green revolution\u2019, induced by global environmental change, is suggested to be one of the major \u2018ecological opportunities\u2019, which probably drove large-scale extinction and range contraction of ochotonids, but inversely promoted diversification and range expansion of leporids.", "keyphrases": ["global environmental change", "ochotonid", "extant pikas", "late miocene", "evolutionary history"]}
{"id": "10.1017/S0094837300013099", "title": "The stratigraphic distribution of fossils", "abstract": "In several increasingly realistic steps, a model of the stratigraphic distribution of fossils is presented. The first and simplest step assumes that if a taxon was extant it will have been preserved. The second step admits that if a taxon was extant, there is some probability less than one that it will have been preserved. This step produces randomly distributed gaps, and fossil ranges that are somewhat shorter than the span of time in which a taxon actually lived. The third step assumes facies-controlled taxa and parasequence-style cyclicity. This produces randomly and nonrandomly distributed gaps, including the anomalously long gaps recognized in confidence limit studies. The final model incorporates depositional sequences and indicates that first and last occurrences will cluster at sequence boundaries and at flooding surfaces in the transgressive systems tract. Across-shelf gradients in diversity, taphonomy, or eurytopy can control the strength, but not the stratigraphic position of these peaks. Comparison of the model to data from the Upper Ordovician suggests that these modeled features are present in the fossil record. Many previously studied paleobiologic patterns may be, at least in part, an artifact of facies control and sequence architecture. Such patterns include gradual or stepwise mass extinction, punctuated morphologic and taxonomic change, iterative evolution, and the replacement of shallow water faunas by deeper water faunas at biomere boundaries.", "keyphrases": ["stratigraphic distribution", "probability", "flooding surface"]}
{"id": "10.7717/peerj.7184", "title": "Osteology and phylogeny of Robustichthys luopingensis, the largest holostean fish in the Middle Triassic", "abstract": "The extinct ray-finned fish taxon Robustichthys luopingensis from Luoping, eastern Yunnan, China represents the largest holostean known in the Middle Triassic. Despite its potential significance for investigating the holostean phylogeny and reconstructing the Triassic marine ecosystems, Robustichthys has so far not been described in detail and its phylogenetic position within the Holostei was controversy. This study provides a redescription and revision of Robustichthys based upon a comparative study of eight type specimens and nine new specimens. Newly recognized information includes a toothed parasphenoid, a pair of premaxillae not pierced by the olfactory nerve, a splint-like quadratojugal, a hatchet-shaped hyomandibula, an hourglass-shaped symplectic, anterior and posterior ceratohyals, a complete series of branchiostegal rays, and sclerotic bones. A revised reconstruction of Robustichthys is presented. Results of a cladistic analysis confirmed Robustichthys as an ionoscopiform within the Halecomorphi; the previous placements of Robustichthys as a basal ginglymodian and Ionoscopidae as a basal amiiform clade are not supported. The sister group relationship between Sinamiinae (Sinamia and Ikechaoamia) and Amiinae (Amia and Cyclurus) within the Amiidae is newly recognized. This revised topology provides new insights into the evolution and historical paleoecology of halecomorph fishes.", "keyphrases": ["phylogeny", "middle triassic", "halecomorphi"]}
{"id": "paleo.007403", "title": "Review of Devonian-Carboniferous Boundary sections in the Rhenish Slate Mountains (Germany)", "abstract": "Thirty Devonian-Carboniferous Boundary sections of the Rhenish Slate Mountains and adjacent subsurface areas are reviewed with respect to litho-, event, conodont, ammonoid, sequence, and chemostratigraphy. In the interval from the base of the uppermost Famennian (Wocklum Beds, Wocklumian) to the base of the middle Tournaisian (base Lower Alum Shale), 11 conodont and 16 ammonoid (sub)zones are distinguished. The terminology of the Hangenberg Crisis Interval is refined, with an overall regressive Crisis Prelude below the main Hangenberg Extinction, which defines the base of the transgressive Lower Crisis Interval (Hangenberg Black Shale). The glacigenic and regressive Middle Crisis Interval (Hangenberg Shale/Sandstone) is followed by the overall transgressive Upper Crisis Interval that can be subdivided into three parts (I to III) with the help of conodont stratigraphy (upper costatus-kockeli Interregnum = upper ckI, Protognathodus kockeli Zone, and lower part of Siphonodella (Eosiphonodella) sulcata s.l./Pr. kuehni Zone). Protognathodus kockeli includes currently a wide range of forms, which variabilities and precise ranges need to be established before a precise GSSP level should be selected. Returning to its original definition, the former Upper duplicata Zone is re-named as Siphonodella (S.) mehli Zone. It replaces the S. (S.) jii Zone, which is hampered by taxonomic complications. The S. (S.) quadruplicata Zone of Ji (1985) is hardly supported by Rhenish data. The entry of typical S. (S.) lobata (M1) characterises an upper subdivision (subzone) of the S. (S.) sandbergi Zone; the new S. (S.) lobata M2 enters much earlier within the S. (S.) mehli Zone. The ammonoid-defined base of the Wocklum-Stufe (Upper Devonian = UD VI) begins with the Linguaclymenia similis Zone (UD VI-A 1 ). The oldest S. (Eosiphonodella) enter within the Muessenbiaergia bisulcata Zone (UD VI-A 2 ). The traditional Parawocklumeria paradoxa Zone of Schindewolf (1937) is divided into successive P. paprothae (VI-C 1 ), P. paradoxa (VI-C 2 ), and Mayneoceras nucleus (VI-C 3 ) Subzones. In the lower Tournaisian (Lower Carboniferous = LC I), the Gattendorfia subinvoluta Zone is subdivided into G. subinvoluta (LC I-A 2 ) and \"Eocanites\" nodosus (LC I-A 3 ) Subzones. The Paprothites dorsoplanus Zone (LC I-B) can be divided into Pap. dorsoplanus (LC I-B 1 ) and Paragattendorfia sphaeroides (LC I-B 2 ) Subzones. Potential subdivisions of the Pseudarietites westfalicus (LC I-C) and Parag. patens Zones (LC I-D) are less distinctive. The unfossiliferous or argillaceous upper part of the Hangenberg Limestone and the overlying Lower Alum Shale Event Interval remain regionally unzoned for ammonoids.", "keyphrases": ["devonian-carboniferous boundary section", "assumed hangenberg limestone", "lithostratigraphic unit", "northern rhenish massif"]}
{"id": "paleo.003343", "title": "A new symmetrodont mammal (Trechnotheria: Zhangheotheriidae) from the Early Cretaceous of China and trechnotherian character evolution", "abstract": "We report the discovery of Anebodon luoi, a new genus and species of zhangheotheriid symmetrodont mammal from the Lujiatun site of the Lower Cretaceous Yixian Formation, China. The fossil is represented by an associated partial skull and dentaries with a nearly complete dentition, and with a dental formula of I4/3 C1/1 P5/4 M3/4. This new taxon lacks the high molar count typical of derived symmetrodonts, differing from the well-represented zhangheotheriids Zhangheotherium and Maotherium in having a postcanine dental formula that resembles more primitive tinodontid symmetrodonts on the one hand, and sister taxa to therians such as Peramus on the other. Upper and lower distal premolars are strongly molariform and are captured undergoing replacement, clarifying positional homology among related taxa. We also describe the rostrum and, for the first time in a symmetrodont, much of the orbital mosaic. Importantly, our new taxon occupies a basal position within the Zhangheotheriidae and permits discussion of trechnotherian character evolution, ultimately shedding additional light on the evolution of therians.", "keyphrases": ["symmetrodont", "trechnotherian character evolution", "yixian formation"]}
{"id": "paleo.011275", "title": "A Simulation-Based Evaluation of Tip-Dating Under the Fossilized Birth\u2013Death Process", "abstract": "Abstract Bayesian molecular dating is widely used to study evolutionary timescales. This procedure usually involves phylogenetic analysis of nucleotide sequence data, with fossil-based calibrations applied as age constraints on internal nodes of the tree. An alternative approach is tip-dating, which explicitly includes fossil data in the analysis. This can be done, for example, through the joint analysis of molecular data from present-day taxa and morphological data from both extant and fossil taxa. In the context of tip-dating, an important development has been the fossilized birth\u2013death process, which allows non-contemporaneous tips and sampled ancestors while providing a model of lineage diversification for the prior on the tree topology and internal node times. However, tip-dating with fossils faces a number of considerable challenges, especially, those associated with fossil sampling and evolutionary models for morphological characters. We conducted a simulation study to evaluate the performance of tip-dating using the fossilized birth\u2013death model. We simulated fossil occurrences and the evolution of nucleotide sequences and morphological characters under a wide range of conditions. Our analyses of these data show that the number and the maximum age of fossil occurrences have a greater influence than the degree of among-lineage rate variation or the number of morphological characters on estimates of node times and the tree topology. Tip-dating with the fossilized birth\u2013death model generally performs well in recovering the relationships among extant taxa but has difficulties in correctly placing fossil taxa in the tree and identifying the number of sampled ancestors. The method yields accurate estimates of the ages of the root and crown group, although the precision of these estimates varies with the probability of fossil occurrence. The exclusion of morphological characters results in a slight overestimation of node times, whereas the exclusion of nucleotide sequences has a negative impact on inference of the tree topology. Our results provide an overview of the performance of tip-dating using the fossilized birth\u2013death model, which will inform further development of the method and its application to key questions in evolutionary biology.", "keyphrases": ["tip-dating", "tree", "simulation study"]}
{"id": "paleo.004125", "title": "Calibration uncertainty in molecular dating analyses: there is no substitute for the prior evaluation of time priors", "abstract": "Calibration is the rate-determining step in every molecular clock analysis and, hence, considerable effort has been expended in the development of approaches to distinguish good from bad calibrations. These can be categorized into a priori evaluation of the intrinsic fossil evidence, and a posteriori evaluation of congruence through cross-validation. We contrasted these competing approaches and explored the impact of different interpretations of the fossil evidence upon Bayesian divergence time estimation. The results demonstrate that a posteriori approaches can lead to the selection of erroneous calibrations. Bayesian posterior estimates are also shown to be extremely sensitive to the probabilistic interpretation of temporal constraints. Furthermore, the effective time priors implemented within an analysis differ for individual calibrations when employed alone and in differing combination with others. This compromises the implicit assumption of all calibration consistency methods, that the impact of an individual calibration is the same when used alone or in unison with others. Thus, the most effective means of establishing the quality of fossil-based calibrations is through a priori evaluation of the intrinsic palaeontological, stratigraphic, geochronological and phylogenetic data. However, effort expended in establishing calibrations will not be rewarded unless they are implemented faithfully in divergence time analyses.", "keyphrases": ["evaluation", "time prior", "divergence time", "calibration"]}
{"id": "10.1029/96jb03267", "title": "Thrusting and exhumation around the margins of the western Tarim basin during the India\u2010Asia collision", "abstract": "The Cenozoic collision between India and Asia has deformed a large part of central Asia. To the north of Tibet around the margins of the western Tarim basin, major basin-vergent thrusting has uplifted and exhumed thick Jurassic to Neogene sedimentary sections; this presumably reflects the propagation of collision-induced deformation into the basin. Apatite fission track data from five sections involved in this thrusting record strong late Oligocene to middle Miocene exhumation and cooling. On the northwest margin of the basin on the piedmont of the Tian Shan, a section exhumed by thrusting yields an exhumation age of 13.6\u00b12.2 Ma (\u00b11\u03c3). Four Miocene sandstones from a second section 40 km to the east yield detrital source area cooling ages which decrease upsection from 25.0\u00b13.9 to 13.1\u00b12.2 Ma. Landsat imagery suggests that probable sediment source areas were dominated by Neogene thrusting, so these ages likely record progressive unroofing in Tian Shan thrust systems. Deformed Miocene to Pleistocene strata indicate that thrusting has continued and propagated basinward up until the present. Previously published apatite data from the Junggar basin on the northern flank of the Tian Shan yield a similar age of 24.7\u00b13.9 Ma. On the southwest margin of Tarim on the piedmont of the western Kunlun Shan, three sections yield cooling ages of 19.8\u00b10.9 Ma, 20.0\u00b13.1 Ma, and roughly 20 Ma. Farther south at Kudi, previous work has yielded apatite cooling ages of 17\u00b12 Ma and a zircon cooling age of 22\u00b12 Ma. These similar cooling ages over a \u2248250 km long belt in the western Kunlun Shan are associated with the transpressional Kumtag fault and the Main Pamir Thrust (MPT). Geologic relations within the western Kunlun Shan suggest that the MPT-Kumtag fault system offsets the originally linear trend of the Paleozoic-early Mesozoic Kunlun arc system by 200\u2013300 km, accommodating much of the Neogene northward indentation of the Pamir block. We propose that the \u224820 Ma ages slightly postdate the initiation of this indentation and consequent crustal thickening. Taken together, the Tian Shan and Kunlun Shan results indicate that crustal thickening, in part accommodated by strike-slip faulting, became the dominant mode of deformation by \u224825\u201320 Ma in a large region extending from the Pamir and west Kunlun Shan north to the Tian Shan.", "keyphrases": ["western tarim basin", "miocene", "thrusting"]}
{"id": "10.1073/pnas.1504020112", "title": "Test of Martin\u2019s overkill hypothesis using radiocarbon dates on extinct megafauna", "abstract": "Significance Coincident with the human colonization of the Western Hemisphere, dozens of genera of Pleistocene megafauna were lost to extinction. Following Martin, we argue that declines in the record of radiocarbon dates of extinct genera may be used as an independent means of detecting the first presence of humans in the New World. Our results, based on analyses of radiocarbon dates from Eastern Beringia, the contiguous United States, and South America, suggest north to south, time, and space transgressive declines in megafaunal populations as predicted by the overkill hypothesis. This finding is difficult to reconcile with other extinction hypotheses. However, it remains to be determined whether these findings will hold with larger samples of radiocarbon dates from all regions. Following Martin [Martin PS (1973) Science 179:969\u2013974], we propose the hypothesis that the timing of human arrival to the New World can be assessed by examining the ecological impacts of a small population of people on extinct Pleistocene megafauna. To that end, we compiled lists of direct radiocarbon dates on paleontological specimens of extinct genera from North and South America with the expectation that the initial decline of extinct megafauna should correspond in time with the initial evidence for human colonization and that those declines should occur first in eastern Beringia, next in the contiguous United States, and last in South America. Analyses of spacings and frequency distributions of radiocarbon dates for each region support the idea that the extinction event first commenced in Beringia, roughly 13,300\u201315,000 BP. For the United States and South America, extinctions commenced considerably later but were closely spaced in time. For the contiguous United States, extinction began at ca. 12,900\u201313,200 BP, and at ca. 12,600\u201313,900 BP in South America. For areas south of Beringia, these estimates correspond well with the first significant evidence for human presence and are consistent with the predictions of the overkill hypothesis.", "keyphrases": ["overkill hypothesis", "radiocarbon date", "south america"]}
{"id": "10.1080/11035891003597083", "title": "True Dalmanella and taxonomic implications for some Late Ordovician dalmanellid brachiopods from North America", "abstract": "Examination of topotype material of the type species of Dalmanella, D. testudinaria, from the Hirnantian strata of Borenshult, southern Sweden, revealed several diagnostic characters that distinguish the type species from some common North American species assigned previously to the genus. The typical Dalmanella testudinaria has a consistently developed, primary medial interspace in the dorsal valve, a cardinal process with an invariably bilobed myophore, punctae of two distinctly different sizes, and a lack of aditicules. In contrast, many Late Ordovician species from North America, such as \u2018Dalmanella\u2019 meeki and \u2018Dalmanella\u2019 multisecta from the Cincinnati type area, consistently have a dorsal medial costa, with a strong tendency to develop aditicules and a trilobate cardinal process. This study confirms the previous notion of many authors that true Dalmanella testudinaria, or the genus as a whole, is either rare or entirely absent in North America. Typical Dalmanella was predominant in cool-water depositional environments (such as the Hirnantia Fauna), whereas the North American dalmanellids (e.g. Cincinnati-type \u2018Dalmanella\u2019, Paucicrura, and Diceromyonia) were most abundant and diverse in tropical, epicontinental sea settings. A clear definition of the true Dalmanella, therefore, has important implications for the study of Late Ordovician\u2013Early Silurian brachiopod evolution, paleoecology, and paleobiogeography.", "keyphrases": ["dalmanella", "brachiopod", "hirnantia fauna"]}
{"id": "paleo.002356", "title": "New Insights into the Skull of Istiodactylus latidens (Ornithocheiroidea, Pterodactyloidea)", "abstract": "The skull of the Cretaceous pterosaur Istiodactylus latidens, a historically important species best known for its broad muzzle of interlocking, lancet-shaped teeth, is almost completely known from the broken remains of several individuals, but the length of its jaws remains elusive. Estimates of I. latidens jaw length have been exclusively based on the incomplete skull of NHMUK R3877 and, perhaps erroneously, reconstructed by assuming continuation of its broken skull pieces as preserved in situ. Here, an overlooked jaw fragment of NHMUK R3877 is redescribed and used to revise the skull reconstruction of I. latidens. The new reconstruction suggests a much shorter skull than previously supposed, along with a relatively tall orbital region and proportionally slender maxilla, a feature documented in the early 20th century but ignored by all skull reconstructions of this species. These features indicate that the skull of I. latidens is particularly distinctive amongst istiodactylids and suggests greater disparity between I. latidens and I. sinensis than previously appreciated. A cladistic analysis of istiodactylid pterosaurs incorporating new predicted I. latidens skull metrics suggests Istiodactylidae is constrained to five species (Liaoxipterus brachyognathus, Lonchengpterus zhoai, Nurhachius ignaciobritoi, Istiodactylus latidens and Istiodactylus sinensis) defined by their distinctive dentition, but excludes the putative istiodactylids Haopterus gracilis and Hongshanopterus lacustris. Istiodactylus latidens, I. sinensis and Li. brachyognathus form an unresolved clade of derived istiodactylids, and the similarity of comparable remains of I. sinensis and Li. brachyognathus suggest further work into their taxonomy and classification is required. The new skull model of I. latidens agrees with the scavenging habits proposed for these pterosaurs, with much of their cranial anatomy converging on that of habitually scavenging birds.", "keyphrases": ["skull", "istiodactylus latiden", "istiodactylid", "liaoxipterus"]}
{"id": "10.1017/S0094837300011519", "title": "Estimation of locomotory forces and stresses in the limb bones of Recent and extinct equids", "abstract": "The locomotory stresses acting at the midshaft of the third metacarpal of Equus are estimated from a geometrical model of the manus during peak loading, which is derived from in vivo data. The stress results compare favorably with those from in vivo strain gage experiments. The model is then modified to account for the anatomical and inferred functional differences in the feet of the two extinct, tridactyl equids Merychippus and Mesohippus, incorporating assumptions from earlier functional studies. Estimates of the stresses in the fossil metacarpals are derived, and fall within the range of values obtained in vivo for limb bones of a wide size range of mammals. The results indicate that the third metacarpal of Merychippus was the most highly stressed and that of Mesohippus the least, with stresses for Equus falling between. Thus the anatomical and functional changes in the manus between Mesohippus and Equus are not simply a result of the difference in body size.", "keyphrases": ["force", "stress", "limb bone", "third metacarpal", "merychippus"]}
{"id": "paleo.008318", "title": "A mitogenomic timetree for Darwin\u2019s enigmatic South American mammal Macrauchenia patachonica", "abstract": "The unusual mix of morphological traits displayed by extinct South American native ungulates (SANUs) confounded both Charles Darwin, who first discovered them, and Richard Owen, who tried to resolve their relationships. Here we report an almost complete mitochondrial genome for the litoptern Macrauchenia. Our dated phylogenetic tree places Macrauchenia as sister to Perissodactyla, but close to the radiation of major lineages within Laurasiatheria. This position is consistent with a divergence estimate of \u223c66 Ma (95% credibility interval, 56.64\u201377.83 Ma) obtained for the split between Macrauchenia and other Panperissodactyla. Combined with their morphological distinctiveness, this evidence supports the positioning of Litopterna (possibly in company with other SANU groups) as a separate order within Laurasiatheria. We also show that, when using strict criteria, extinct taxa marked by deep divergence times and a lack of close living relatives may still be amenable to palaeogenomic analysis through iterative mapping against more distant relatives.", "keyphrases": ["perissodactyla", "litopterna", "phylogenetic analysis"]}
{"id": "10.1371/journal.pone.0257523", "title": "Early development and coloniality in Oligophylloides from the Devonian of Morocco\u2014Are Heterocorallia Palaeozoic octocorals?", "abstract": "Heterocorals represent an enigmatic group of Palaeozoic corals, known from relatively short time intervals in the Devonian and Carboniferous periods. The major differences between Heterocorallia and other Palaeozoic corals are the lack of an external theca (epitheca), lack of calices and the presence of dichotomously dividing septa-like structures. Heterocoral skeleton was presumably externally covered by the soft tissue and each branch of their skeleton has, until now, been regarded as a corallite\u2013a skeleton of a single polyp. We investigated upper Famennian Oligophylloides from Morocco, focussing on branching processes, wall structure, previously poorly known initial growth stages and the growing tip, described here for the first time. We demonstrate that Oligophylloides shows a unique colony development not known in any group of anthozoans possessing a septate-like architecture and suggest that the previously postulated homology between true septa in hexa- and rugose corals on one hand, and Oligophylloides on the other, must be rejected. Based on the skeleton structure and branching patterns, we postulate, contrary to former ideas, that the stem and branches of heterocorals represent the skeleton of a multi-polyp colonial coral, similar to many extant octocorals. We found numerous potential homologies with octocoral skeletons (notably the Keratoisidinae within the Isididae) and, as a result, we propose the inclusion of the order Heterocorallia within the subclass Octocorallia. This suggestion requires, however, further research on the other taxa of heterocorals. We also propose some changes to the morphological terminology for the Heterocorallia.", "keyphrases": ["oligophylloides", "devonian", "epitheca"]}
{"id": "10.1029/2007PA001462", "title": "Impact of skeletal dissolution and secondary aragonite on trace element and isotopic climate proxies in Porites corals", "abstract": "Restricted zones of recent dissolution and secondary aragonite infilling were identified in a coral core collected in 1986 from a living massive Porites colony from the central Great Barrier Reef, Australia. Secondary aragonite needles, \u226520 \u03bcm long, cover skeletal surfaces deposited from 1972 to late 1974 and increase bulk density by 10%. Dissolution is observed above this zone, whereas older skeleton is pristine. We investigate the impact of both types of early marine diagenesis on skeletal geochemistry and coral paleoclimate reconstructions by comparison with similar records from eight contemporary Porites colonies collected at nearby reefs. Secondary aragonite overgrowth causes anomalies in skeletal density, Mg/Ca, Sr/Ca, U/Ca, \u03b4 O, and \u03b4C. The secondary aragonite is consistently associated with a cool temperature anomaly for each of the sea surface temperature (SST) proxies (\u03b4O-SST -1.6\u00b0C; Sr/Ca-SST -1.7\u00b0C; Mg/Ca-SST -1.9\u00b0C; U/Ca-SST -2.8\u00b0C). Dissolution, through incongruent leaching, also causes cool SST artifacts but only for trace element ratios (Mg/Ca-SST -1.2\u00b0C; Sr/Ca-SST -1.2\u00b0C; U/Ca-SST -2.1\u00b0C). The sequence of preference with respect to dissolution of coral skeleton in seawater is Mg > Ca > Sr > U. Rigorous screening of coral material for paleoclimate reconstructions is therefore necessary to detect both dissolution and the presence of secondary minerals. The excellent agreement between apparent SST anomalies generated by different modes of diagenesis means that replication of tracers within a single coral cannot be used to validate climate-proxy interpretations. Poor replication of records between different coral colonies, however, provides a strong indication of nonclimatic artifacts such as dissolution and secondary aragonite. Copyright 2007 by the American Geophysical Union.", "keyphrases": ["dissolution", "secondary aragonite", "coral"]}
{"id": "paleo.000701", "title": "Silurian craniide brachiopods from Gotland", "abstract": "Seven craniide brachiopod genera are described from the Silurian (Wenlock\u2013Ludlow) of Gotland, including one new genus and five new species. The new genus and species Thulecrania septicostata is unique among Silurian craniides as it possesses solid spines. The new species Lepidocrania multilamellosa is the first Silurian record of this poorly known Permian genus. The problematic North American Propatella Grubbs, , was originally described as a gastropod, but the new species Propatella palmaria from Gotland shows that it is a craniide with sutured hollow spines of a type not previously recorded from Silurian craniides. The dorsal valves of the new species Valdiviathyris? bicornis are remarkably similar to those of the type species and represent the first possible Palaeozoic record of this poorly known extant craniide. This first systematic study of craniide brachiopods from the Silurian of Gotland shows that the diversity is relatively high as compared to other known Silurian craniide faunas, but a more thorough comparison is not possible due to the lack of data from most parts of the world. The new data from Gotland support the view that the craniides were not affected by the end\u2010Ordovician extinction.", "keyphrases": ["craniide brachiopod", "gotland", "gastropod"]}
{"id": "10.1666/05062.1", "title": "Substrate affinity and diversity dynamics of Paleozoic marine animals", "abstract": "Abstract Short-term fluctuations in the diversification rate of Paleozoic marine animal genera are more strongly correlated with extinction-rate variation than with origination-rate variation. Diversity dynamics are strikingly different in the Mesozoic and Cenozoic, when variation in origination is more important than extinction. Data on the lithologic context of taxonomic occurrences in the Paleobiology Database are used to assess the substrate affinities of Paleozoic genera. The greater role of extinction-rate variation in the Paleozoic is found to characterize genera with an affinity for carbonate substrates but not those that prefer terrigenous clastic substrates. It is therefore plausible that the Paleozoic to post-Paleozoic shift in diversity dynamics is underlain in part by the secular decline in the relative areal extent of carbonate environments, and the concomitant decline in the relative diversity of carbonate- versus clastic-loving taxa.", "keyphrases": ["diversity dynamic", "origination", "substrate affinity"]}
{"id": "10.1126/science.abi6984", "title": "Reproductive innovations and pulsed rise in plant complexity", "abstract": "Description Evolutionary pulses of complexity The evolution of land plants has been marked by an increase in the complexity of reproductive structures. Leslie et al. analyzed the temporal pattern of this increase in a study of fossil and extant land plants across the entire paleontological record. Reproductive complexity increased in two widely separated pulses corresponding to key innovations in reproductive biology: the origin of seeds in the very late Devonian and the origin of flowering plants in the mid-Cretaceous almost 250 million years later. After the origin of flowers, there was a rapid expansion in the morphological complexity of flowering plants. In contrast to many aspects of animal morphological diversity, which expanded early in evolutionary history, most complexity in plants was achieved relatively late. \u2014AMS Increases in plant reproductive complexity in two widely separated pulses were associated with major evolutionary innovations. Morphological complexity is a notable feature of multicellular life, although whether it evolves gradually or in early bursts is unclear. Vascular plant reproductive structures, such as flowers, are familiar examples of complex morphology. In this study, we use a simple approach based on the number of part types to analyze changes in complexity over time. We find that reproductive complexity increased in two pulses separated by ~250 million years of stasis, including an initial rise in the Devonian with the radiation of vascular plants and a pronounced increase in the Late Cretaceous that reflects flowering plant diversification. These pulses are associated with innovations that increased functional diversity, suggesting that shifts in complexity are linked to changes in function regardless of whether they occur early or late in the history of vascular plants.", "keyphrases": ["innovation", "rise", "reproductive structure", "flower", "vascular plant"]}
{"id": "10.1111/cla.12212", "title": "Phylogenetic analyses with four new Cretaceous bristletails reveal inter\u2010relationships of Archaeognatha and Gondwana origin of Meinertellidae", "abstract": "Based on fifteen Archaeognatha (=Microcoryphia) specimens from Myanmar (Burmese) amber, including males, females and immatures, two new genera and four species, Cretaceomachilis longa sp.n., Unimeinertellus abundus gen. et sp.n., U. bellus sp.n. and Nullmeinertellus wenxuani gen. et sp.n., are described. Phylogenetic analyses of taxa in Archaeognatha were conducted using Maximum parsimony and Bayesian inference based on morphological characters and DNA sequence data. Our results confirm the phylogenetic position of the new genera, clarify the monophyly of Meinertellidae and indicate that the \u2018paleo\u2010types\u2019 excluding Ditrigoniophthalmus are nested within the Machilidae group, but suggest that the three subfamilies within Machilidae may be artificial. The diversity of meinertellids with derived characters found from the Cretaceous indicate that the divergence time of Machilidae and Meinertellidae is much earlier than the Cretaceous. We propose the possibility that Meinertellidae might have originated on Gondwana.", "keyphrases": ["archaeognatha", "meinertellidae", "phylogenetic analysis", "tropical forest community", "southeastern asia"]}
{"id": "10.1098/rstb.2015.0217", "title": "The uncertain role of diversity dependence in species diversification and the need to incorporate time-varying carrying capacities", "abstract": "There is no agreement among palaeobiologists or biologists as to whether, or to what extent, there are limits on diversification and species numbers. Here, we posit that part of the disagreement stems from: (i) the lack of explicit criteria for defining the relevant species pools, which may be defined phylogenetically, ecologically or geographically; (ii) assumptions that must be made when extrapolating from population-level logistic growth to macro-evolutionary diversification; and (iii) too much emphasis being placed on fixed carrying capacities, rather than taking into account the opportunities for increased species richness on evolutionary timescales, for example, owing to increased biologically available energy, increased habitat complexity and the ability of many clades to better extract resources from the environment, or to broaden their resource base. Thus, we argue that a more effective way of assessing the evidence for and against the ideas of bound versus unbound diversification is through appropriate definition of the relevant species pools, and through explicit modelling of diversity-dependent diversification with time-varying carrying capacities. Here, we show that time-varying carrying capacities, either increases or decreases, can be accommodated through changing intrinsic diversification rates (diversity-independent effects), or changing the effects of crowding (diversity-dependent effects).", "keyphrases": ["time-varying carrying capacity", "iii", "diversification rate"]}
{"id": "paleo.010251", "title": "Phloem sap in Cretaceous ambers as abundant double emulsions preserving organic and inorganic residues", "abstract": "Fossilized remains preserved in amber provide abundant data on the paleobiota surrounding the resin-producing plants, but relatively scarcer information about the resinous sources themselves. Here, dark pseudoinclusions in kidney-shaped amber pieces from the Early Cretaceous (Albian) amber from Spain are studied. This type of fossilized remain, abundant in Cretaceous ambers, was first interpreted as fossilized vacuole-bearing microorganisms, but later regarded as artifactual and probably secreted by the resinous trees, although their origin remained unclear. Using complementary microscopy (light, electron, confocal), spectroscopy (infrared, micro-Raman), mass spectrometry and elemental analysis techniques, we demonstrate that the pseudoinclusions correspond to droplets of phloem sap containing amber spheroids and preserving both organic and inorganic residues consistent with degraded components from the original sap. The amber pieces containing pseudoinclusions are fossilized, resin-in-sap-in-resin double emulsions, showing banding patterns with differential content of resin-in-sap emulsion droplets. Our findings represent the first time fossilized phloem sap, 105 million years old, has been recognized and characterized, and open new lines of paleontological research with taxonomic, taphonomic, physiological and ecological implications.", "keyphrases": ["double emulsion", "microorganism", "resinous tree", "phloem sap"]}
{"id": "paleo.005060", "title": "Neurocranial anatomy of the petalichthyid placoderm Shearsbyaspis oepiki Young revealed by X\u2010ray computed microtomography", "abstract": "Stem\u2010group gnathostomes reveal the sequence of character acquisition in the origin of modern jawed vertebrates. The petalichthyids are placoderm\u2010grade stem\u2010group gnathostomes known from both isolated skeletal material and rarer articulated specimens of one genus. They are of particular interest because of anatomical resemblances with osteostracans, the jawless sister group of jawed vertebrates. Because of this, they have become central to debates on the relationships of placoderms and the primitive cranial architecture of gnathostomes. However, among petalichthyids, only the braincase of Macropetalichthys has been studied in detail, and the diversity of neurocranial morphology in this group remains poorly documented. Using X\u2010ray computed microtomography, we investigated the endocranial morphology of Shearsbyaspis oepiki Young, a three\u2010dimensionally preserved petalichthyid from the Early Devonian of Taemas\u2010Wee Jasper, Australia. We generated virtual reconstructions of the external endocranial surfaces, orbital walls and cranial endocavity, including canals for major nerves and blood vessels. The neurocranium of Shearsbyaspis resembles that of Macropetalichthys, particularly in the morphology of the brain cavity, nerves and blood vessels. Many characters, including the morphology of the pituitary vein canal and the course of the trigeminal nerve, recall the morphology of osteostracans. Additionally, the presence of a parasphenoid in Shearsbyaspis (previously not known with confidence outside of arthrodires and osteichthyans) raises some questions about current proposals of placoderm paraphyly. Our detailed description of this specimen adds to the known morphological diversity of petalichthyids, and invites critical reappraisal of the phylogenetic relationships of placoderms.", "keyphrases": ["placoderm", "x\u2010ray", "microtomography"]}
{"id": "10.1002/evan.21560", "title": "The origins and early elaboration of projectile technology", "abstract": "The ability of Homo sapiens to kill prey at a distance is arguably one of the catalysts for our current ecological dominance. Many researchers have suggested its origins lie in the African Middle Stone Age or the European Middle Palaeolithic (\u223c300\u201030 thousand years ago), but the perishable components of armatures rarely preserve. Most research on this subject therefore emphasises analysis of armature tip size, shape, and diagnostic impacts or residues. Other lines of evidence have included human skeletal anatomy or analyses of the species composition of faunal assemblages. Projectile Impact Marks (PIMs) on archaeofaunal remains offer an ideal complement to this work, but their potential has been restricted mainly to the later Eurasian zooarchaeological record. A review of current evidence and approaches shows that systematic PIM research could add much to our understanding of early projectile technology, especially in Africa.", "keyphrases": ["projectile technology", "archaeofaunal remain", "review"]}
{"id": "10.1111/bor.12252", "title": "Spatial simulation and modelling of the early Pleistocene site of DS (Bed I, Olduvai Gorge, Tanzania): a powerful tool for predicting potential archaeological information from unexcavated areas", "abstract": "Spatial statistical models are powerful tools for creating simulation and prediction models. Here, we apply such models to the newly discovered 1.84 Ma site of DS (Bed I, Olduvai Gorge, Tanzania). Ongoing excavation has already exposed 370 m2 of the same discrete archaeological level. This is the biggest window into an Early Pleistocene anthropogenic site. With such a large area opened, modelling based on spatial trends (using coordinates) and on covariates (topography) has enabled the creation of predictions about where the densest concentrations of unexcavated materials may lie. Following this modelling, excavation has confirmed the predictions; the densest clusters of stone tools and fossils bones are palaeotopographically and palaeoecologically influenced. Spatial statistical analysis is, therefore, a powerful analytical tool to model and understand in\u2010site and off\u2010site hominin behaviour as an interaction between hominins and environments.", "keyphrases": ["modelling", "tanzania", "anthropogenic site"]}
{"id": "10.1080/14772019.2018.1466374", "title": "A skeleton of a Uintan machaeroidine \u2018creodont\u2019 and the phylogeny of carnivorous eutherian mammals", "abstract": "An edentulous partial skeleton of a carnivorous mammal from the Uinta Formation (middle Eocene) of Utah is referred to the rare and enigmatic sabre-tooth clade Machaeroidinae primarily on the basis of alveolar patterns and cranial morphology. The newly recognized skeleton includes portions of both girdles, all long bones, and the first known tarsal and phalangeal material of a machaeroidine. The specimen permits a preliminary reconstruction of the locomotor habits of machaeroidines, which appear to have been adapted to scansorial or arboreal rather than terrestrial locomotion. The new material also prompts a review of machaeroidine affinities, which have been unresolved for over a century, with consensus opinion favouring a link to either oxyaenid or limnocyonine hyaenodontid \u2018creodonts\u2019. Postcranial evidence favours a link to oxyaenids, as machaeroidines share numerous features with oxyaenids that are lacking in hyaenodontids. To test this relationship machaeroidines were included in a phylogenetic analysis broadly sampling early carnivorous eutherians, including members of both \u2018Creodonta\u2019 and Carnivoramorpha. Results place Machaeroidinae within Oxyaenidae but fail to support either \u2018creodont\u2019 or carnivoramorphan monophyly. Instead, Oxyaenidae is linked with Carnivoraformes, while Viverravidae is basally positioned among carnivorous eutherians. Reconsideration of the character evidence cited in support of Carnivoramorpha indicates that many features are ambiguous in the context of a broad sample of \u2018creodonts\u2019 and early carnivoramorphans. Hyaenodontid monophyly is also not recovered but this likely reflects the influence of one morphologically divergent genus, Arfia.", "keyphrases": ["creodont", "carnivorous eutherian mammal", "middle eocene", "machaeroidinae", "phylogenetic analysis"]}
{"id": "10.1666/09067.1", "title": "The Neogene transition from C3 to C4 grasslands in North America: assemblage analysis of fossil phytoliths", "abstract": "Abstract The rapid ecological expansion of grasses with C4 photosynthesis at the end of the Neogene (8-2 Ma) is well documented in the fossil record of stable carbon isotopes. As one of the most profound vegetation changes to occur in recent geologic time, it paved the way for modern tropical grassland ecosystems. Changes in CO2 levels, seasonality, aridity, herbivory, and fire regime have all been suggested as potential triggers for this broadly synchronous change, long after the evolutionary origin of the C4 pathway in grasses. To date, these hypotheses have suffered from a lack of direct evidence for floral composition and structure during this important transition. This study aimed to remedy the problem by providing the first direct, relatively continuous record of vegetation change for the Great Plains of North America for the critical interval (ca. 12-2 Ma) using plant silica (phytolith) assemblages. Phytoliths were extracted from late Miocene\u2013Pliocene paleosols in Nebraska and Kansas. Quantitative phytolith analysis of the 14 best-preserved assemblages indicates that habitats varied substantially in openness during the middle to late Miocene but became more uniformly open, corresponding to relatively open grassland or savanna, during the late Miocene and early Pliocene. Phytolith data also point to a marked increase of grass short cells typical of chloridoid and other potentially C4 grasses of the PACMAD clade between 8 and 5 Ma; these data suggest that the proportion of these grasses reached up to \u223c50\u201360% of grasses, resulting in mixed C3-C4 and highly heterogeneous grassland communities by 5.5 Ma. This scenario is consistent with interpretations of isotopic records from paleosol carbonates and ungulate tooth enamel. The rise in abundance of chloridoids, which were present in the central Great Plains since the early Miocene, demonstrates that the \u201cglobally\u201d observed lag between C4 grass evolution/taxonomic diversification and ecological expansion occurred at the regional scale. These patterns of vegetation alteration imply that environmental change during the late Miocene\u2013Pliocene played a major role in the C3-C4 shift in the Great Plains. Specifically, the importance of chloridoids as well as a decline in the relative abundance of forest indicator taxa, including palms, point to climatic drying as a key trigger for C4 dominance.", "keyphrases": ["grassland", "north america", "phytolith", "miocene"]}
{"id": "paleo.005822", "title": "A new neosuchian crocodylomorph (Crocodyliformes, Mesoeucrocodylia) from the Early Cretaceous of north\u2010east Brazil", "abstract": "Abstract:\u2002 A new neosuchian crocodylomorph, Susisuchus jaguaribensis sp. nov., is described based on fragmentary but diagnostic material. It was found in fluvial\u2010braided sediments of the Lima Campos Basin, north\u2010eastern Brazil, 115\u2003km from where Susisuchus anatoceps was found, in rocks of the Crato Formation, Araripe Basin. S. jaguaribensis and S. anatoceps share a squamosal\u2013parietal contact in the posterior wall of the supratemporal fenestra. A phylogenetic analysis places the genus Susisuchus as the sister group to Eusuchia, confirming earlier studies. Because of its position, we recovered the family name Susisuchidae, but with a new definition, being node\u2010based group including the last common ancestor of Susisuchus anatoceps and Susisuchus jaguaribensis and all of its descendents. This new species corroborates the idea that the origin of eusuchians was a complex evolutionary event and that the fossil record is still very incomplete.", "keyphrases": ["new neosuchian crocodylomorph", "susisuchus jaguaribensis", "lima campos basin"]}
{"id": "10.1017/S1477201905001525", "title": "Skeletal homologies, phylogeny and classification of the earliest asterozoan echinoderms", "abstract": "Synopsis A thorough reappraisal of extant and fossil asterozoan plate systems is used to construct working hypotheses of primary plate homologies for Ordovician Asterozoa. Results indicate that inferomarginal ossicles of asteroids, somasteroids and the primitive ophiuroid Phragmactis are likely to be homologous with edrioasteroid marginals. The intermediate virgals and coverplates of somasteroids are identified as modified actinals and the sub\u2010laterals of certain stenurids are axial, here termed podial plates, with laterals in these taxa homologous to true lateral plates and adambulacrals of ophiuroids and asteroids, respectively. The nature of the asterozoan mouth frame is reinvestigated as a result of new study of the mouth frames of key taxa, with a reappraisal of existing developmental and symmetry data. It is argued that primitive asterozoan mouth angle plates were entirely ambulacral and probably not spine\u2010bearing, but that mouth spines evolved in asteroids and ophiuroids either on the existing first ambulacrals or by the superposition of first adambulacrals adoral to first ambulacrals. These new data are used to undertake a cladistic analysis of all known genera of Ordovician asterozoan echinoderms (38 taxa), based on a dataset of 150 morphological characters, rooted on the Middle Cambrian edrioasteroid taxa Stromatocystites and Cambraster. The resulting tree is fully resolved although some deeper branches show poor support. It reveals that Ordovician asteroids form a monophyletic group (defined by the presence of an unpaired axillary inferomarginal, opposing ambulacrals and blocky abutting adambulacrals) and are a sister group to the remainingasterozoans, including the somasteroids. Somasteroids are monophyletic and, with the primitive taxon Phragmactis, are a sister group to the remaining ophiuroids. The class Ophiuroidea is diagnosed by the near\u2010simultaneous appearance of apomorphies including an interradial disc with highly separated arms and aboral and oral interambulacral longitudinal musculature. A phylogenetic tree constructed for asterozoans based on current stratigraphic occurrence data indicates that at the time of their first appearance, asteroids and ophiuroid body plans were already established. This suggests a significant but unobserved pre\u2010Ordovician history. Comparison of observed and phylogenetic diversity together with the appearance of relatively young taxa close to the base of the tree point to a poor asterozoan record, particularly in the Lower Ordovician. A revised classification for stem\u2010group asterozoans is proposed based on well\u2010supported clades with the new taxon Eopentaroida erected. Mapping of character states on the most parsimonious solution suggests that whilst asteroid morphological evolution was conservative in the Ordovician, ophiuroids underwent a profound morphological diversification. Functionally, these changes are linked to the adoption of carnivory by derived Ordovician ophiuroids. In contrast, asteroids probably remained dominantly deposit\u2010feeders throughout the period. Character distribution on the cladogram refutes none of the hypotheses of primary plate homology, although it suggests that podial ossicles were developed in two clades independently and that the marginals of eopentaroids may not be homologous to those of other asterozoans and edrioasteroids.", "keyphrases": ["phylogeny", "asterozoan echinoderm", "ordovician asterozoa", "ophiuroid", "arm"]}
{"id": "paleo.000928", "title": "Non\u2010traditional isotope perspectives in vertebrate palaeobiology", "abstract": "The recent development of multi\u2010collector inductively coupled plasma mass spectrometry (MC\u2010ICP\u2010MS) notably in the disciplines of earth sciences, now allows the precise measurement of isotope ratios, even at low concentration. Non\u2010traditional isotope systems, such as alkaline earth (Ca, Mg) and transition (Cu, Fe, Zn) metals are now being measured in a variety of biological tissues, including bone and teeth. Although our understanding of the environmental and biological mechanisms behind the fractionation of such elements is still in its infancy, some of these isotopes are suspected to fractionate along the food chain, as has been reported in the literature for calcium, magnesium and zinc. Other geochemical methods, such as concentration analyses, permit a prior assessment of diagenesis in the fossils and such an approach indicates that in some circumstances, not only enamel but also dentine or bone can preserve its original biogenic composition. The aims here are to: review the current knowledge surrounding these various isotopic tools; address their potential preservation in biological apatite; and provide the palaeobiologist with a guide to the different toolkits available, including a discussion of their potential applications in vertebrate palaeobiology with a case study involving two mammal assemblages from the Pleistocene of Europe.", "keyphrases": ["vertebrate palaeobiology", "fractionation", "calcium"]}
{"id": "paleo.010545", "title": "On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness", "abstract": "The size and flight mechanics of giant pterosaurs have received considerable research interest for the last century but are confused by conflicting interpretations of pterosaur biology and flight capabilities. Avian biomechanical parameters have often been applied to pterosaurs in such research but, due to considerable differences in avian and pterosaur anatomy, have lead to systematic errors interpreting pterosaur flight mechanics. Such assumptions have lead to assertions that giant pterosaurs were extremely lightweight to facilitate flight or, if more realistic masses are assumed, were flightless. Reappraisal of the proportions, scaling and morphology of giant pterosaur fossils suggests that bird and pterosaur wing structure, gross anatomy and launch kinematics are too different to be considered mechanically interchangeable. Conclusions assuming such interchangeability\u2014including those indicating that giant pterosaurs were flightless\u2014are found to be based on inaccurate and poorly supported assumptions of structural scaling and launch kinematics. Pterosaur bone strength and flap-gliding performance demonstrate that giant pterosaur anatomy was capable of generating sufficient lift and thrust for powered flight as well as resisting flight loading stresses. The retention of flight characteristics across giant pterosaur skeletons and their considerable robustness compared to similarly-massed terrestrial animals suggest that giant pterosaurs were not flightless. Moreover, the term \u2018giant pterosaur\u2019 includes at least two radically different forms with very distinct palaeoecological signatures and, accordingly, all but the most basic sweeping conclusions about giant pterosaur flight should be treated with caution. Reappraisal of giant pterosaur material also reveals that the size of the largest pterosaurs, previously suggested to have wingspans up to 13 m and masses up to 544 kg, have been overestimated. Scaling of fragmentary giant pterosaur remains have been misled by distorted fossils or used inappropriate scaling techniques, indicating that 10\u201311 m wingspans and masses of 200\u2013250 kg are the most reliable upper estimates of known pterosaur size.", "keyphrases": ["giant pterosaur", "pterosaur", "flightless", "body plan", "modification"]}
{"id": "paleo.004085", "title": "An integrated approach to understanding the role of the long neck in plesiosaurs", "abstract": "The evolution and function of the long neck in plesiosaurs, and how the problems associated with stiffness or flexibility were overcome during feeding, or rapid swimming during predator avoidance, are explored, and a new interpretation for the function of the plesiosaur neck is presented. Based on the anatomy of the articular faces of contiguous cervical vertebral centra, neural arches, and cervical ribs, the plesiosaur neck was mainly adapted for ventral bending, with dorsal, lateral and rotational movements all relatively restricted. Predominant ventral bending indicates the neck was adapted for use beneath the body, suggesting feeding in the water column, close to the sea floor, or within soft sediments on the sea floor. A new model is proposed for the plesiosaur bauplan, comprising the head as a filter, straining, sieve feeding or sediment raking apparatus, mounted on a neck which acted as a stiff but ventrally flexible feeding tube, attached to the body which acted as a highly mobile feeding platform. Numerous features of plesiosaurs, including cranial and dental form, cervical vertebral morphology, body shape and limb-based propulsion, conform to this model. Comparative data from modern organisms support this novel explanation for the structure and function of the plesiosaur long neck. This integrative analysis offers an explanation for the evolution of the plesiosaur long neck as a key evolutionary novelty, and why this apparently enigmatic feature remained a prominent feature of plesiosaurs throughout their long evolutionary history.", "keyphrases": ["long neck", "plesiosaur", "neural arch", "morphology"]}
{"id": "10.1017/S0094837300021308", "title": "Variation in dinosaur skeletochronology indicators: implications for age assessment and physiology", "abstract": "Twelve different bones from the skeleton of the holotype specimen of the hadrosaurian dinosaur Hypacrosaurus stebingeri were thin-sectioned to evaluate the significance of lines of arrested growth (LAGs) in age assessments. The presence of an external fundamental system (EFS) at the external surface of the cortex and mature epiphyses indicate that the Hypacrosaurus specimen had reached adulthood and growth had slowed considerably from earlier stages. The number of LAGs varied from none in the pedal phalanx to as many as eight in the tibia and femur. Most elements had experienced considerable Haversian reconstruction that had most likely obliterated many LAGs. The tibia was found to have experienced the least amount of reconstruction, but was still not optimal for skeletochronology because the LAGs were difficult to count near the periosteal surface. Additionally, the numbers of LAGs within the EFS vary considerably around the circumference of a single element and among elements. Counting LAGs from a single bone to assess skeletochronology appears to be unreliable, particularly when a fundamental system exists. Because LAGs are plesiomorphic for tetrapods, and because they are present in over a dozen orders of mammals, they have no particular physiological meaning that can be generalized to particular amniote groups without independent physiological evidence. Descriptions of dinosaur physiology as \u201cintermediate\u201d between the physiology of living reptiles and that of living birds and mammals may or may not be valid, but cannot be based reliably on the presence of LAGs.", "keyphrases": ["age assessment", "physiology", "different bone", "circumference", "growth mark"]}
{"id": "10.5194/fr-20-37-2016", "title": "Odyssey in the evolution of a paleopathologist", "abstract": "Abstract. A recent report suggesting perceived limitations of and opportunities in the study of paleopathology suggested the importance of incorporation of scientific methodologies. It seems reasonable to also explore how those methodologies are developed and, indeed, how one approaches paleopathology as a science. The development of one such paleopathologist is delineated from his serendipitous observations to application of hypothesis generation and subsequent testing approach developed during basic medical science education. This approach resulted in recognition of how much he thought he knew was actually contrary to the facts. A critical factor was the collaborative approach with specialists in other fields, wherein linguistic confusion was overcome and perspectives refined by point\u2013counterpoint analysis of hypotheses. The limited reliability of tertiary information was clearly exposed through examination of primary sources \u2013 original articles rather than what might be referred to as \"meta-analyses\". It became clear that linguistics was not the only challenge; application of techniques had to be observed and validated. Without validation one might obtain precision (method repeatedly reveals same results) but at the expense of accuracy (assurance that the method actually assesses the question). Paleontological studies are generally limited to examination of organisms and their traces. Archeologically based studies incorporate additional sources of information (e.g., historic), but are no less subject to such semantic and methodological issues. Proof of concept studies provided new windows to recognition not only of disease but to previous anatomical challenges (e.g., localization of direct muscle attachment sites and distribution). Trans-phylogenetic representation of disease falsified speculation that \"evolution\" would preclude analysis through time. Pathology is an intrinsic component of life and transcends both species and time. Knowledge gained in a given species and time can be applied to similar disease manifestations in other species in modern time. Once speculations were tested and either verified or falsified, paleo-epidemiologic approach allowed identification of patterns of spread and even application of that knowledge to recognition of human migration patterns. Proof of concept studies provided new windows to recognition not only of disease but to previous anatomical challenges (e.g., localization of direct muscle attachment sites and distribution).", "keyphrases": ["paleopathologist", "recognition", "disease"]}
{"id": "10.1093/zoolinnean/zlz026", "title": "Infernovenator steenae, a new serpentine recumbirostran from the \u2018Mazon Creek\u2019 Lagerst\u00e4tte further clarifies lysorophian origins", "abstract": "\n The Carboniferous (Pennsylvanian; 309\u2013307 Mya) \u2018Mazon Creek\u2019 Lagerst\u00e4tte produces some of the earliest tetrapod fossils of major Palaeozoic lineages. Previously, the Mazon Creek record of lysorophians was known from a single poorly preserved specimen consisting only of a partial vertebral column. Here we describe a new, virtually complete lysorophian genus and species, Infernovenator steenae gen. & sp. nov. on the basis of a unique combination of characters, including a near complete circumorbital series and the retention of a postfrontal. Parsimony-based phylogenetic analysis placed the new taxon in the family Molgophidae, as sister to Brachydectes newberryi. Those results and the more generalized cranial morphology present in Infernovenator further support a recumbirostran origin of Molgophidae. Co-occurrence of two morphologically and functionally distinct molgophids in the Early Moscovian suggests a rapid and underappreciated diversification of this family in the Early Pennsylvanian.", "keyphrases": ["recumbirostran", "mazon creek", "tetrapod fossil", "infernovenator"]}
{"id": "10.1111/j.1365-2117.2009.00408.x", "title": "Jurassic synorogenic basin filling in western Korea: sedimentary response to inception of the western Circum\u2010Pacific orogeny", "abstract": "This is the first sedimentologic and stratigraphic attempt to demonstrate Jurassic subduction\u2010induced basin\u2010filling processes in the early stage of the western Circum\u2010Pacific orogeny. The Chungnam Basin in western Korea was filled with a Lower to Middle Jurassic nonmarine succession, the Nampo Group, whose deposition postdated the Triassic final assembly of Chinese continental blocks. The Nampo Group consists of two repeated, fining\u2010 to coarsening\u2010upward alluvio\u2010lacustrine sequences, separated by an interval of thick breccia\u2013gravel progradation deposits and its related strong proximal unconformities. No temporal variation in the degree of chemical weathering, along with the predominance of coals and a tropic to subtropic paleoflora, reveals little or no climate fluctuations during deposition of the Nampo Group. The observed relationships provide a record of sedimentation most likely controlled by temporal variations of tectonically driven sediment flux. Such syntectonic sedimentation of the Chungnam Basin occurred at a convergent margin of continental\u2010arc setting during the Daebo orogeny, synchronous with the early subduction of the western paleo\u2010Pacific ocean that resulted in formation of an accretionary complex along the East Asian continental margin during Jurassic time. Hence, synorogenic deposition in the Chungnam Basin is interpreted as sedimentary response to subduction\u2013accretion of the western paleo\u2010Pacific plate.", "keyphrases": ["sedimentary response", "western circum\u2010pacific orogeny", "chungnam basin", "daebo orogeny"]}
{"id": "paleo.000550", "title": "Upper Palaeolithic genomes reveal deep roots of modern Eurasians", "abstract": "We extend the scope of European palaeogenomics by sequencing the genomes of Late Upper Palaeolithic (13,300 years old, 1.4-fold coverage) and Mesolithic (9,700 years old, 15.4-fold) males from western Georgia in the Caucasus and a Late Upper Palaeolithic (13,700 years old, 9.5-fold) male from Switzerland. While we detect Late Palaeolithic-Mesolithic genomic continuity in both regions, we find that Caucasus hunter-gatherers (CHG) belong to a distinct ancient clade that split from western hunter-gatherers B45 kya, shortly after the expansion of anatomically modern humans into Europe and from the ancestors of Neolithic farmers B25 kya, around the Last Glacial Maximum. CHG genomes significantly contributed to the Yamnaya steppe herders who migrated into Europe B3,000 BC, supporting a formative Caucasus influence on this important Early Bronze age culture. CHG left their imprint on modern populations from the Caucasus and also central and south Asia possibly marking the arrival of Indo-Aryan languages.", "keyphrases": ["caucasus hunter-gatherer", "chg", "upper palaeolithic"]}
{"id": "paleo.000815", "title": "THERAPSIDS FROM THE PERMIAN CHIWETA BEDS AND THE AGE OF THE KAROO SUPERGROUP IN MALAWI", "abstract": "Exposures of the Karoo Supergroup occur in the northern and southern portions of Malawi, south central Africa. The section in southern Malawi contains Lower Permian coal-bearing shales and extends upward to the Chikwawa basalt of Jurassic age (179 Ma). The Chikwawa basalt represents the northern limit of the Karoo Large Igneous Province, which signals the rifting of Gondwana. The Chiweta Beds of northern Malawi contain a Late Permian (Cistecephalus Zone; 256-258 Ma) fauna, including the dicynodont Oudenodon and a new burnetiamorph biarmosuchian more derived than Lemurosaurus and sister to Proburnetia, Burnetia, and Bullacephalus.", "keyphrases": ["chiweta beds", "karoo supergroup", "gondwana"]}
{"id": "10.1080/14772019.2012.704948", "title": "The oldest known metriorhynchid super-predator: a new genus and species from the Middle Jurassic of England, with implications for serration and mandibular evolution in predacious clades", "abstract": "The Oxford Clay Formation of England has yielded numerous sympatric species of metriorhynchid crocodylomorphs, although disagreement has persisted regarding the number of valid species. For over 140 years teeth reminiscent of the genus Dakosaurus have been known from the Oxford Clay Formation but these have never been properly described and their taxonomy and systematic affinity remain contentious. Furthermore, an enigmatic mandible and associated postcranial skeleton discovered by Alfred Leeds in the Fletton brick pits near Peterborough also remains undescribed. We show that this specimen, and several isolated teeth, represents the oldest known remains of a large-bodied predatory metriorhynchid. This material is described herein and referred to Tyrannoneustes lythrodectikos gen. et sp. nov. This species has a unique occlusal pattern: the dentition was arranged so that the posterior maxillodentary teeth interlock in the same plane and occlude mesiodistally. It is the first described crocodylomorph with microscopic denticles that are not contiguous along the carinae (forming short series of up to 10 denticles) and do not noticeably alter the height of the keel. Additionally, the dorsally expanded and curved posterior region of the mandible ventrally displaced the dentary tooth row relative to the jaw joint facilitating the enlargement of the dentition and increasing optimum gape. Therefore, Tyrannoneustes would have been a large-bodied marine predator that was well-suited to feed on larger prey than other contemporaneous metriorhynchids. A new phylogenetic analysis finds Tyrannoneustes to be the sister taxon to the subclade Geosaurini. An isolated tooth, humerus, and well-preserved mandible suggest a second species of metriorhynchid super-predator may also have lived in the Oxford Clay sea. Finally, we revise the diagnoses and descriptions of the other Oxford Clay metriorhynchid species, providing a guide for differentiating the many contemporaneous taxa from this exceptional fossil assemblage. http://zoobank.org/urn:lsid:zoobank.org:pub:C6222858-EC36-430D-8E28-1F636A6697CA", "keyphrases": ["metriorhynchid super-predator", "england", "serration", "denticle", "geosaurini"]}
{"id": "10.1080/14772019.2020.1748132", "title": "A new cymbospondylid ichthyosaur (Ichthyosauria) from the Middle Triassic (Anisian) of the Augusta Mountains, Nevada, USA", "abstract": "A new taxon, Cymbospondylus duelferi sp. nov., is described from the late Anisian of the Fossil Hill Member of the Favret Formation of the Augusta Mountains, Pershing County, Nevada, USA. The holotype and only specimen consists of a fairly complete skull associated with articulated and disarticulated postcranial material. Body length reconstruction revealed a medium-sized individual with an estimated body length of 4.3 m. Dorsal vertebrae as well as the left humerus of this specimen are associated with three strings of articulated tail and posterior dorsal vertebrae, which are on average 68% smaller than the vertebrae of the medium-sized individual. Due to the small size of these vertebrae and their position within the trunk region, they most likely represent fetuses. Cymbospondylus duelferi sp. nov. provides the second-oldest evidence for viviparity in ichthyosaurs. In the course of this study, the skull morphology of C. petrinus and C. nichollsi was reviewed, resulting in revised character scorings for both. Phylogenetic analyses demonstrate a sister-taxon relationship of the new taxon with C. petrinus, which was found in the same stratigraphic unit, the Fossil Hill Member, that also crops out at the classical Fossil Hill locality in the Humboldt Range, where the member is part of the Prida Formation. Cymbospondylus duelferi sp. nov. shares a very similar skull morphology with C. petrinus and C. nichollsi, whereas the shoulder girdle morphology differs. Because there is no evidence for ontogenetic differences or sexual dimorphism in the new specimen, a third species of Cymbospondylus \u2013 neglecting the type species C. piscosus that is only known from five vertebrae \u2013 is recognized from the Fossil Hill Member. Further occurrences of the genus in the Lower and Middle Triassic of Svalbard (Boreal Ocean) and Europe (Tethys) point to a very fast radiation and dispersal of cymbospondylids during the Middle Triassic. https://zoobank.org:pub:906F5F32-9090-496D-8FC7-680D25EED5EF", "keyphrases": ["ichthyosaur", "middle triassic", "cymbospondylus"]}
{"id": "paleo.011908", "title": "From body scale ontogeny to species ontogeny: Histological and morphological assessment of the Late Devonian acanthodian Triazeugacanthus affinis from Miguasha, Canada", "abstract": "Growth series of Palaeozoic fishes are rare because of the fragility of larval and juvenile specimens owing to their weak mineralisation and the scarcity of articulated specimens. This rarity makes it difficult to describe early vertebrate growth patterns and processes in extinct taxa. Indeed, only a few growth series of complete Palaeozoic fishes are available; however, they allow the growth of isolated elements to be described and individual growth from these isolated elements to be inferred. In addition, isolated and in situ scales are generally abundant and well-preserved, and bring information on (1) their morphology and structure relevant to phylogenetic relationships and (2) individual growth patterns and processes relative to species ontogeny. The Late Devonian acanthodian Triazeugacanthus affinis from the Miguasha Fossil-Lagerst\u00e4tte preserves one of the best known fossilised ontogenies of early vertebrates because of the exceptional preservation, the large size range, and the abundance of complete specimens. Here, we present morphological, histological, and chemical data on scales from juvenile and adult specimens (scales not being formed in larvae). Histologically, Triazeugacanthus scales are composed of a basal layer of acellular bone housing Sharpey\u2019s fibers, a mid-layer of mesodentine, and a superficial layer of ganoine. Developmentally, scales grow first through concentric addition of mesodentine and bone around a central primordium and then through superposition of ganoine layers. Ontogenetically, scales form first in the region below the dorsal fin spine, then squamation spreads anteriorly and posteriorly, and on fin webs. Phylogenetically, Triazeugacanthus scales show similarities with acanthodians (e.g. \u201cbox-in-box\u201d growth), chondrichthyans (e.g. squamation pattern), and actinopterygians (e.g. ganoine). Scale histology and growth are interpreted in the light of a new phylogenetic analysis of gnathostomes supporting acanthodians as stem chondrichthyans.", "keyphrases": ["species ontogeny", "vertebrate", "phylogenetic analysis"]}
{"id": "paleo.003237", "title": "The evolutionary history of polycotylid plesiosaurians", "abstract": "Polycotylidae is a clade of plesiosaurians that appeared during the Early Cretaceous and became speciose and abundant early in the Late Cretaceous. However, this radiation is poorly understood. Thililua longicollis from the Middle Turonian of Morocco is an enigmatic taxon possessing an atypically long neck and, as originally reported, a series of unusual cranial features that cause unstable phylogenetic relationships for polycotylids. We reinterpret the holotype specimen of Thililua longicollis and clarify its cranial anatomy. Thililua longicollis possesses an extensive, foramina-bearing jugal, a premaxilla\u2013parietal contact and carinated teeth. Phylogenetic analyses of a new cladistic dataset based on first-hand observation of most polycotylids recover Thililua and Mauriciosaurus as successive lineages at the base of the earliest Late Cretaceous polycotyline radiation. A new dataset summarizing the Bauplan of polycotylids reveals that their radiation produced an early burst of disparity during the Cenomanian\u2013Turonian interval, with marked plasticity in relative neck length, but this did not arise as an ecological release following the extinction of ichthyosaurs and pliosaurids. This disparity vanished during and after the Turonian, which is consistent with a model of \u2018early experimentation/late constraint\u2019. Two polycotylid clades, Occultonectia clade nov. and Polycotylinae, survived up to the Maastrichtian, but with low diversity.", "keyphrases": ["plesiosaurian", "polycotylidae", "phylogenetic analysis"]}
{"id": "10.1017/S009483730001191X", "title": "Swimming capabilities of Mesozoic marine reptiles: implications for method of predation", "abstract": "Body shape and mode of swimming were major factors that affected the swimming capabilities of Mesozoic marine reptiles. By estimating the total drag and the amount of energy available through metabolism, the maximum sustained swimming speed was calculated for 115 marine reptile specimens. Calculated sustained swimming speeds range from 1.8 to 2.7 m/sec, but are probably too high by as much as a factor of two. Mesozoic marine reptiles were probably much slower than modern toothed whales. The diversification of fast, agile teleost fish in the Cretaceous may have therefore contributed to the decline of the marine reptiles. Long-bodied reptiles appear to have had slower sustained swimming speeds than deep-bodied forms of the same length. For a given length, ichthyosaurs were probably faster sustained swimmers than plesiosaurs, and plesiosaurs were probably faster sustained swimmers than crocodiles and mosasaurs. This suggests that the long-bodied forms probably used an ambush technique to capture prey, to maximize the range of possible prey and to minimize competition with the faster pursuit predators.", "keyphrases": ["marine reptile", "predator", "body shape", "ichthyosaur", "swimming capability"]}
{"id": "10.1080/02724634.2015.1054036", "title": "Miocene and Early Pleistocene Rodents (Mammalia) from Denizli Basin (Southwestern Turkey) and a New Species of Fossil Mus", "abstract": "ABSTRACT \n The terrestrial Neogene Basin of Denizli, located in southwestern Turkey, yields rodent faunas from nine localities dated between MN6 and MNQ18\u201319. Arabosminthus gansus, which is known in China and Mongolia, is recorded for the first time in Turkey at the Yenicekent localities (MN8\u20139), an older stratigraphical level than it is usually known from. Another species from the same localities, Microdyromys complicatus, is described for the first time in Anatolia in a younger locality than usual known in Western Europe. Myomimus dehmi, Myocricetodon eskihisarensis, Dryomys tosyaensis, and Dryomys sp. are the other species described in the present study. A new species of fossil Mus (Mammalia, Rodentia), Mus denizliensis, sp. nov. (MNQ18\u201319), has been found at the G\u20acokp\u0131nar locality. This is the oldest fossil species of this genus known from Turkey or continental Europe.", "keyphrases": ["southwestern turkey", "fossil mus", "mus denizliensis"]}
{"id": "paleo.010674", "title": "Synchrotron Reveals Early Triassic Odd Couple: Injured Amphibian and Aestivating Therapsid Share Burrow", "abstract": "Fossorialism is a beneficial adaptation for brooding, predator avoidance and protection from extreme climate. The abundance of fossilised burrow casts from the Early Triassic of southern Africa is viewed as a behavioural response by many tetrapods to the harsh conditions following the Permo-Triassic mass-extinction event. However, scarcity of vertebrate remains associated with these burrows leaves many ecological questions unanswered. Synchrotron scanning of a lithified burrow cast from the Early Triassic of the Karoo unveiled a unique mixed-species association: an injured temnospondyl amphibian (Broomistega) that sheltered in a burrow occupied by an aestivating therapsid (Thrinaxodon). The discovery of this rare rhinesuchid represents the first occurrence in the fossil record of a temnospondyl in a burrow. The amphibian skeleton shows signs of a crushing trauma with partially healed fractures on several consecutive ribs. The presence of a relatively large intruder in what is interpreted to be a Thrinaxodon burrow implies that the therapsid tolerated the amphibian\u2019s presence. Among possible explanations for such unlikely cohabitation, Thrinaxodon aestivation is most plausible, an interpretation supported by the numerous Thrinaxodon specimens fossilised in curled-up postures. Recent advances in synchrotron imaging have enabled visualization of the contents of burrow casts, thus providing a novel tool to elucidate not only anatomy but also ecology and biology of ancient tetrapods.", "keyphrases": ["early triassic", "amphibian", "thrinaxodon"]}
{"id": "paleo.007993", "title": "New long-proboscid lacewings of the mid-Cretaceous provide insights into ancient plant-pollinator interactions", "abstract": "Many insects with long-proboscid mouthparts are among the pollinators of seed plants. Several cases of the long-proboscid pollination mode are known between fossil insects (e.g., true flies, scorpionflies, and lacewings) and various extinct gymnosperm lineages, beginning in the Early Permian and increasing during the Middle Jurassic to Early Cretaceous. However, details on the morphology of lacewing proboscides and the relevant pollination habit are largely lacking. Here we report on three lacewing species that belong to two new genera and a described genus from mid-Cretaceous (Albian-Cenomanian) amber of Myanmar. All these species possess relatively long proboscides, which are considered to be modified from maxillary and labial elements, probably functioning as a temporary siphon for feeding on nectar. Remarkably, these proboscides range from 0.4\u20131.0 mm in length and are attributed to the most diminutive ones among the contemporary long-proboscid insect pollinators. Further, they clearly differ from other long-proboscid lacewings which have a much longer siphon. The phylogenetic analysis indicates that these Burmese long-proboscid lacewings belong to the superfamily Psychopsoidea but cannot be placed into any known family. The present findings represent the first description of the mouthparts of long-proboscid lacewings preserved in amber and highlight the evolutionary diversification of the ancient plant-pollinator interactions.", "keyphrases": ["long-proboscid lacewing", "ancient plant-pollinator interaction", "insect", "cretaceous", "long proboscis"]}
{"id": "paleo.001514", "title": "Eocene fossil is earliest evidence of flower-visiting by birds", "abstract": "Birds are important pollinators, but the evolutionary history of ornithophily (bird pollination) is poorly known. Here, we report a skeleton of the avian taxon Pumiliornis from the middle Eocene of Messel in Germany with preserved stomach contents containing numerous pollen grains of an eudicotyledonous angiosperm. The skeletal morphology of Pumiliornis is in agreement with this bird having been a, presumably nectarivorous, flower-visitor. It represents the earliest and first direct fossil evidence of flower-visiting by birds and indicates a minimum age of 47 million years for the origin of bird\u2013flower interactions. As Pumiliornis does not belong to any of the modern groups of flower-visiting birds, the origin of ornithophily in some angiosperm lineages may have predated that of their extant avian pollinators.", "keyphrases": ["flower-visiting", "stomach content", "pollen grain"]}
{"id": "paleo.001438", "title": "Diversity change during the rise of tetrapods and the impact of the \u2018Carboniferous rainforest collapse\u2019", "abstract": "The Carboniferous and early Permian were critical intervals in the diversification of early four-limbed vertebrates (tetrapods), yet the major patterns of diversity and biogeography during this time remain unresolved. Previous estimates suggest that global tetrapod diversity rose continuously across this interval and that habitat fragmentation following the \u2018Carboniferous rainforest collapse\u2019 (CRC) drove increased endemism among communities. However, previous work failed to adequately account for spatial and temporal biases in sampling. Here, we reassess early tetrapod diversity and biogeography with a new global species-level dataset using sampling standardization and network biogeography methods. Our results support a tight relationship between observed richness and sampling, particularly during the Carboniferous. We found that subsampled species richness initially increased into the late Carboniferous, then decreased substantially across the Carboniferous/Permian boundary before slowly recovering in the early Permian. Our analysis of biogeography does not support the hypothesis that the CRC drove endemism; instead, we found evidence for increased cosmopolitanism in the early Permian. While a changing environment may have played a role in reducing diversity in the earliest Permian, our results suggest that the CRC was followed by increased global connectivity between communities, possibly reflecting both reduced barriers to dispersal and the diversification of amniotes.", "keyphrases": ["tetrapod", "carboniferous rainforest collapse", "biogeography", "endemism", "sampling"]}
{"id": "paleo.011446", "title": "Hagfish from the Cretaceous Tethys Sea and a reconciliation of the morphological\u2013molecular conflict in early vertebrate phylogeny", "abstract": "Significance Jawless, boneless, and virtually without fossil record, hagfish have long escaped systematists\u2019 grip on their place among other fish. Yet their systematic resolution is critical to define vertebrates as a clade. Here we report an unequivocal fossil hagfish from the Cretaceous Mediterranean. Using this fossil to calibrate the evolutionary history of the group, our analysis supports hagfish and lampreys as sister groups, which likely diverged from one another in early Paleozoic times. As a result, vertebrates have a deep dichotomy, where some fossil jawless vertebrates sit closer to hagfish and lampreys than to jawed vertebrates. We showed that morphology-based analysis converged onto molecular inferences when characters are coded nonindependently, providing a case study for morphological\u2013molecular conflicts in animal phylogeny. Hagfish depart so much from other fishes anatomically that they were sometimes considered not fully vertebrate. They may represent: (i) an anatomically primitive outgroup of vertebrates (the morphology-based craniate hypothesis); or (ii) an anatomically degenerate vertebrate lineage sister to lampreys (the molecular-based cyclostome hypothesis). This systematic conundrum has become a prominent case of conflict between morphology- and molecular-based phylogenies. To date, the fossil record has offered few insights to this long-branch problem or the evolutionary history of hagfish in general, because unequivocal fossil members of the group are unknown. Here, we report an unequivocal fossil hagfish from the early Late Cretaceous of Lebanon. The soft tissue anatomy includes key attributes of living hagfish: cartilages of barbels, postcranial position of branchial apparatus, and chemical traces of slime glands. This indicates that the suite of characters unique to living hagfish appeared well before Cretaceous times. This new hagfish prompted a reevaluation of morphological characters for interrelationships among jawless vertebrates. By addressing nonindependence of characters, our phylogenetic analyses recovered hagfish and lampreys in a clade of cyclostomes (congruent with the cyclostome hypothesis) using only morphological data. This new phylogeny places the fossil taxon within the hagfish crown group, and resolved other putative fossil cyclostomes to the stem of either hagfish or lamprey crown groups. These results potentially resolve the morphological\u2013molecular conflict at the base of the Vertebrata. Thus, assessment of character nonindependence may help reconcile morphological and molecular inferences for other major discords in animal phylogeny.", "keyphrases": ["morphological\u2013molecular conflict", "vertebrate", "lamprey", "cyclostomes", "phylogenetic analysis"]}
{"id": "paleo.002341", "title": "Modelling determinants of extinction across two Mesozoic hyperthermal events", "abstract": "The Late Triassic and Early Toarcian extinction events are both associated with greenhouse warming events triggered by massive volcanism. These Mesozoic hyperthermals were responsible for the mass extinction of marine organisms and resulted in significant ecological upheaval. It has, however, been suggested that these events merely involved intensification of background extinction rates rather than significant shifts in the macroevolutionary regime and extinction selectivity. Here, we apply a multivariate modelling approach to a vast global database of marine organisms to test whether extinction selectivity varied through the Late Triassic and Early Jurassic. We show that these hyperthermals do represent shifts in the macroevolutionary regime and record different extinction selectivity compared to background intervals of the Late Triassic and Early Jurassic. The Late Triassic mass extinction represents a more profound change in selectivity than the Early Toarcian extinction but both events show a common pattern of selecting against pelagic predators and benthic photosymbiotic and suspension-feeding organisms, suggesting that these groups of organisms may be particularly vulnerable during episodes of global warming. In particular, the Late Triassic extinction represents a macroevolutionary regime change that is characterized by (i) the change in extinction selectivity between Triassic background intervals and the extinction event itself; and (ii) the differences in extinction selectivity between the Late Triassic and Early Jurassic as a whole.", "keyphrases": ["mass extinction", "extinction selectivity", "global warming"]}
{"id": "10.1073/pnas.1504985112", "title": "New Age of Fishes initiated by the Cretaceous\u2212Paleogene mass extinction", "abstract": "Significance Ray-finned fishes are the most diverse and ecologically dominant group of vertebrates on the planet. Previous molecular phylogenies and paleontological studies have shown that modern ray-finned fishes (crown teleosts) radiated sometime in the Late Cretaceous or early Paleogene. Our data suggest that crown teleosts came into their current dominant ecological role in pelagic ecosystems immediately following the Cretaceous\u2212Paleogene mass extinction 66 million years ago by filling newly vacated ecological niches and marking the beginning of an \u201cage of ray-finned fishes.\u201d Our study is, to our knowledge, the first geographically comprehensive, high-resolution study of marine vertebrate communities across the extinction. Ray-finned fishes (Actinopterygii) comprise nearly half of all modern vertebrate diversity, and are an ecologically and numerically dominant megafauna in most aquatic environments. Crown teleost fishes diversified relatively recently, during the Late Cretaceous and early Paleogene, although the exact timing and cause of their radiation and rise to ecological dominance is poorly constrained. Here we use microfossil teeth and shark dermal scales (ichthyoliths) preserved in deep-sea sediments to study the changes in the pelagic fish community in the latest Cretaceous and early Paleogene. We find that the Cretaceous\u2212Paleogene (K/Pg) extinction event marked a profound change in the structure of ichthyolith communities around the globe: Whereas shark denticles outnumber ray-finned fish teeth in Cretaceous deep-sea sediments around the world, there is a dramatic increase in the proportion of ray-finned fish teeth to shark denticles in the Paleocene. There is also an increase in size and numerical abundance of ray-finned fish teeth at the boundary. These changes are sustained through at least the first 24 million years of the Cenozoic. This new fish community structure began at the K/Pg mass extinction, suggesting the extinction event played an important role in initiating the modern \u201cage of fishes.\u201d", "keyphrases": ["cretaceous\u2212paleogene mass extinction", "ray-finned fish", "shark", "fish community", "extinction event"]}
{"id": "10.1017/pab.2021.21", "title": "Dietary and body-mass reconstruction of the Miocene neotropical bat Notonycteris magdalenensis (Phyllostomidae) from La Venta, Colombia", "abstract": "Abstract. With 14 species recorded, the Miocene La Venta bat fauna is the most diverse bat paleocommunity in South America. It includes the oldest plant-visiting bat in the New World and some of the earliest representatives of the extant families Phyllostomidae, Thyropteridae, and Noctilionidae. La Venta's Notonycteris magdalenensis is an extinct member of the subfamily Phyllostominae, a group of modern Neotropical animalivorous bats, and is commonly included in studies of the evolution of Neotropical bats, but aspects of its biology remain unclear. In this study, we used multivariate dental topography analysis (DTA) to reconstruct the diet of N. magdalenensis by quantitatively comparing measures of molar complexity with those of 25 modern noctilionoid species representing all major dietary habits in bats. We found clear differences in molar complexity between dietary guilds, indicating that DTA is potentially an informative tool to study bat ecomorphology. Our results suggest N. magdalenensis was probably an omnivore or insectivore, rather than a carnivore like its modern relatives Chrotopterus auritus and Vampyrum spectrum. Also, we reconstructed the body mass of N. magdalenensis to be \u223c95 g, larger than most insectivorous bats, but smaller than the largest carnivorous bat (V. spectrum). Our results confirm that N. magdalenensis was not a specialized carnivore. It remains to be demonstrated that the specialized carnivory ecological niche was occupied by the same lineage of phyllostomines from at least the middle Miocene. Combining our diet and body-mass reconstructions, we suggest that N. magdalenensis exhibits morphological pre-adaptations crucial for the evolution of specialized carnivory.", "keyphrases": ["body-mass reconstruction", "miocene", "bat"]}
{"id": "10.5710/AMGH.23.06.2016.2966", "title": "Metacryphaeus Tuberculatus and Metacryphaeus australis (Trilobita, Phacopida) from the Devonian of the Paran\u00e1 Basin: Taxonomy and Paleobiogeography", "abstract": "Abstract. \n Calmoniid trilobites of the genus Metacryphaeus Reed include M. tuberculatus (Kozlowski), M. kegeli Carvalho, Edgecombe and Lieberman, M. meloi Carvalho, Edgecombe and Lieberman, M. rotundatus (Kozlowski), M. giganteus (Ulrich), M. convexus (Ulrich), M. curvigena Lieberman, M. branisai Lieberman, M. caffer (Salter), M. australis (Clarke), and M. allardyceae (Clarke). The geographic distribution of this genus comprises areas of Gondwana, including Bolivia, Peru, Brazil, the Falkland Islands, and South Africa. This study reports a new occurrence of M. tuberculatus in the Paran\u00e1 Basin (Goi\u00e1s and Paran\u00e1 states, Brazil), in both the Alto Gar\u00e7as and the Apucarana sub-basins. Metacryphaeus tuberculatus was compared with all Metacryphaeus species and, especially, with M. australis, which also represents a new record for the Paran\u00e1 Basin. These new records of M. tuberculatus imply a different dispersion interpretation from that which is known through the literature. Metacryphaeus tuberculatus seems to have originated during the Early Devonian and lived in areas such as Bolivia, Peru, and the Apucarana Sub-basin (Paran\u00e1 Basin, Brazil). The dispersion between these areas is probably related to the Emsian transgression. During the Givetian, the species presumably migrated towards the Alto Gar\u00e7as Sub-basin (Paran\u00e1 Basin, Brazil) and the Parna\u00edba Basin. These facts provide an alternative paleogeographic interpretation to that presented by Tropidoleptus Hall and Exaesiodiscus Moore and Jeffords in Gondwana and suggest a different pattern of migration during the Devonian of Brazil.", "keyphrases": ["devonian", "falkland islands", "metacryphaeus tuberculatus"]}
{"id": "paleo.008537", "title": "Decaying in different clays: implications for soft\u2010tissue preservation", "abstract": "Lagerst\u00e4tten, places where soft\u2010bodied organisms became mineralized, provide a substantial bulk of palaeobiological information, but the detailed mechanisms of how soft\u2010tissue preservation takes place remain debatable. An experimental taphonomy approach, which allows for direct study of decay and mineralization, offers a means to study the preservational potential of different soft\u2010bodied organisms under controlled conditions. Here we compare the preservational capacity of two types of clay (kaolinite and montmorillonite) through a long\u2010term (24 month) experiment involving the burial and decay of small crustaceans. Our experimental design is innovative in that it models catastrophic sedimentation in fine\u2010grained colloidal suspension, which is believed to form Lagerst\u00e4tten deposits. We demonstrated better preservation of buried organisms in clays compared to water, and in kaolinite compared to montmorillonite. As aluminium cations were present in high concentrations in kaolinite sediment but not in montmorillonite, the better preservation in kaolinite is attributed to the tanning properties of aluminium, which catalyses cross\u2010linking in proteins, protecting them from bacterial degradation. Anaerobic environments and acidification also slow down decay, but they are less effective than tanning. Kaolinite and montmorillonite replaced the crustacean integuments differently: in the remains buried in kaolinite, Al and Si were detected in equal proportions, while in those buried in montmorillonite, the Si content appeared to be much higher even in comparison with the initial sample of the clay. These variations probably arose from the different dynamics of acidic hydrolysis in the two clays associated with anaerobic decomposition of organic matter. Our results show that the preservation mechanism includes multi\u2010component interactions between the solution, mineral, sediment and organic remains; taken separately, any single component explains little. The specific conditions that occur within the colloidal clay sediments can facilitate conservation and start fast mineralization according to chemical properties and elemental content.", "keyphrases": ["clay", "soft\u2010tissue preservation", "mineralization", "decay"]}
{"id": "paleo.004183", "title": "New evidence from China for the nature of the pterosaur evolutionary transition", "abstract": "Pterosaurs are extinct flying reptiles, the first vertebrates to achieve powered flight. Our understanding of the evolutionary transition between basal, predominantly long-tailed forms to derived short-tailed pterodactyloids remained poor until the discovery of Wukongopterus and Darwinopterus in western Liaoning, China. In this paper we report on a new genus and species, Douzhanopterus zhengi, that has a reduced tail, 173% the length of the humerus, and a reduced fifth pedal digit, whose first phalange is ca. 20% the length of metatarsal III, both unique characters to Monofenestra. The morphological comparisons and phylogenetic analysis presented in this paper demonstrate that Douzhanopterus is the sister group to the \u2018Painten pro-pterodactyloid\u2019 and the Pterodactyloidea, reducing the evolutionary gap between long- and short-tailed pterosaurs.", "keyphrases": ["china", "pterosaur", "evolutionary transition", "douzhanopterus zhengi"]}
{"id": "10.1073/pnas.1110633108", "title": "Estimating the timing of early eukaryotic diversification with multigene molecular clocks", "abstract": "Although macroscopic plants, animals, and fungi are the most familiar eukaryotes, the bulk of eukaryotic diversity is microbial. Elucidating the timing of diversification among the more than 70 lineages is key to understanding the evolution of eukaryotes. Here, we use taxon-rich multigene data combined with diverse fossils and a relaxed molecular clock framework to estimate the timing of the last common ancestor of extant eukaryotes and the divergence of major clades. Overall, these analyses suggest that the last common ancestor lived between 1866 and 1679 Ma, consistent with the earliest microfossils interpreted with confidence as eukaryotic. During this interval, the Earth's surface differed markedly from today; for example, the oceans were incompletely ventilated, with ferruginous and, after about 1800 Ma, sulfidic water masses commonly lying beneath moderately oxygenated surface waters. Our time estimates also indicate that the major clades of eukaryotes diverged before 1000 Ma, with most or all probably diverging before 1200 Ma. Fossils, however, suggest that diversity within major extant clades expanded later, beginning about 800 Ma, when the oceans began their transition to a more modern chemical state. In combination, paleontological and molecular approaches indicate that long stems preceded diversification in the major eukaryotic lineages.", "keyphrases": ["eukaryote", "diversification", "fungus"]}
{"id": "paleo.006687", "title": "Dinosaur teeth from the Jurassic Qigu and Shishugou Formations of the Junggar Basin (Xinjiang/China) and their paleoecologic implications", "abstract": "The Middle and early Late Jurassic Qigu and Shishugou Formations of the southern and central Junggar Basin yielded teeth of theropods (Theropoda indet.), sauropods (Eusauropoda indet.), and stegosaurs. The dinosaur assemblage of the southern Junggar Basin is less diverse and is represented by smaller forms than in the central part of the basin. The microwear of the teeth of Eusauropoda indet. resembles that observed in Camarasaurus and may have formed as a result of biting through resistant woody materials. Carbon and oxygen isotope data of the sauropod and theropod teeth indicate feeding within a C 3 -plant ecosystem in a continental setting. Differences in enamel d 13 C and d 18 O values between Eusauropoda indet. and the theropod teeth are comparable to those observed in other herbivorous and carnivorous vertebrates, and suggest at least partial preservation of original dietary signals.", "keyphrases": ["jurassic qigu", "shishugou formations", "junggar basin", "sauropod"]}
{"id": "paleo.001152", "title": "Diversification events and the effects of mass extinctions on Crocodyliformes evolutionary history", "abstract": "The rich fossil record of Crocodyliformes shows a much greater diversity in the past than today in terms of morphological disparity and occupation of niches. We conducted topology-based analyses seeking diversification shifts along the evolutionary history of the group. Our results support previous studies, indicating an initial radiation of the group following the Triassic/Jurassic mass extinction, here assumed to be related to the diversification of terrestrial protosuchians, marine thalattosuchians and semi-aquatic lineages within Neosuchia. During the Cretaceous, notosuchians embodied a second diversification event in terrestrial habitats and eusuchian lineages started diversifying before the end of the Mesozoic. Our results also support previous arguments for a minor impact of the Cretaceous/Palaeogene mass extinction on the evolutionary history of the group. This argument is not only based on the information from the fossil record, which shows basal groups surviving the mass extinction and the decline of other Mesozoic lineages before the event, but also by the diversification event encompassing only the alligatoroids in the earliest period after the extinction. Our results also indicate that, instead of a continuous process through time, Crocodyliformes diversification was patchy, with events restricted to specific subgroups in particular environments and time intervals.", "keyphrases": ["crocodyliformes", "neosuchia", "mesozoic", "diversification event"]}
{"id": "paleo.001523", "title": "Decoding the Evolution of Melanin in Vertebrates.", "abstract": "Melanins are widespread pigments in vertebrates, with important roles in visual signaling, UV protection, and homeostasis. Fossil evidence of melanin and melanin-bearing organellesmelanosomesin ancient vertebrates may illuminate the evolution of melanin and its functions, but macroevolutionary trends are poorly resolved. Here, we integrate fossil data with current understanding of melanin function, biochemistry, and genetics. Mapping key genes onto phenotypic attributes of fossil vertebrates identifies potential genomic controls on melanin evolution. Taxonomic trends in the anatomical location, geometry, and chemistry of vertebrate melanosomes are linked to the evolution of endothermy. These shifts in melanin biology suggest fundamental links between melanization and vertebrate ecology. Tissue-specific and taxonomic trends in melanin chemistry support evidence for evolutionary tradeoffs between function and cytotoxicity.\nMelanins (see Glossary) are dark to rufous pigments that are widespread in vertebrates and underpin critical functions in physiology and behavior [1] . Fossil evidence of melanin extending to over 300 million years ago has triggered a paradigm shift in paleobiology, prompting remarkable reconstructions of the coloration and behavior of extinct vertebrates [2] [3] [4] [5] [6] . New discoveries of internal melanins in vertebrate fossils have broadened our understanding of the functional diversity of ancient melanins [7-9] and invite a re-evaluation of the macroevolutionary history of melanin and its functions. Here, we synthesize trends in the fossil record of melanin and explore fossil evidence for the evolution of melanin function and the genetic basis of melanization. This highlights the value of the fossil record as a resource for tracking melanin evolution through deep time.\nIn extant vertebrates, melanin occurs as micron-sized organelles, melanosomes, in the integument, eyes and internal tissues and functions in photoprotection, visual signaling, thermoregulation, immunity, antioxidation, mechanical strengthening, and abrasion resistance [6, 10, 11] (Figure 1 , Box 1). It is unclear which functions evolved first and which selection pressures dominate [11, 12] . Fossils preserving evidence of melanin offer a unique temporal perspective.\nMelanin has been reported from fossil vertebrates from >25 localities from the Carboniferous to the Pliocene (Table S1 in the supplemental information online). The fossils include cyclostomes, fish, frogs, lizards, and other squamates, ichthyosaurs, plesiosaurs, turtles, pterosaurs, feathered and nonfeathered dinosaurs, birds, and mammals. This phylogenetically and temporally broad dataset yields evidence for ancient functions of melanin (Figure 2 ).\nIn extant vertebrates melanin fulfils diverse roles including visual communication, photoprotection, antioxidation, and mechanical strengthening of tissues, but the evolution of these functions is debated.\nThe discovery that melanosomes in fossil and modern vertebrates are associated with tissue-specific suites of trace metals supports hypotheses that melanin has ancient functions in metal homeostasis and antioxidant regulation.\nShifts in melanosome biology across the dinosaur-bird transition reveal intimate links between adaptive and pleiotropic processes relating to the evolution of endothermy, metal homeostasis, photoprotection and the lymphatic system. Key genes can be mapped onto color pattern phenotypes in fossil vertebrates.\nMelanin-based coloration in vertebrates is dominated by melanin forms associated with low cytotoxicity, possibly reflecting selective adaptation against forms linked with greater oxidative stress or co-option of melanin forms with specific metal binding behavior for coloration.", "keyphrases": ["melanin", "visual signaling", "homeostasis"]}
{"id": "paleo.007875", "title": "An acid-free method of microfossil extraction from clay-rich lithologies using the surfactant Rewoquat", "abstract": "Marine rocks characterized by high clay content provide excellent conditions for fossil preservation, particularly for organic-walled microfossils such as retiolitid graptolites and chitinozoans. Nevertheless, the phyllosilicate minerals, which constitute the clay component, make microfossil extractions difficult. The problem results from the tendency of phyllosilicates to form aggregates in low pH values, as standard methods of microfossil extraction employ acids for rock digestion. Consequently, the use of acids for clay-rich rocks is often inefficient and time-consuming. We propose a method of rock disintegration using the surfactant Rewoquat and compare it with two commonly applied approaches: digestion in buffered acetic acid and in HCl-HF. Using examples from the Mulde Brick-clay Member from the Silurian of Gotland and the Daleje Shale from the Devonian of the Prague Basin we observed that disintegration in Rewoquat was faster (days) than digestion in acid (months), and allowed to recover calcareous in addition to organic-walled fossils. The yield and preservation was comparably good, except for conodonts, which were strongly etched after using HCl-HF. Retiolitid graptolites recovered using Rewoquat were preserved in 3D and showed a lower degree of fragmentation. The fossil content of the residue obtained using Rewoquat was higher due to dispersion of clay aggregates. For observation of delicate fossils we recommend to coat the sample with the surfactant. Application of Rewoquat can reveal the most delicate forms and growth stages, and thus provide a better insight into the ontogeny, autecology, and body size distributions of a number of fossil groups.", "keyphrases": ["microfossil extraction", "surfactant rewoquat", "disintegration"]}
{"id": "10.1002/palo.20060", "title": "Understanding long\u2010term carbon cycle trends: The late Paleocene through the early Eocene", "abstract": "(1) The late Paleocene to the early Eocene (\ufffd 58-52 Ma) was marked by significant changes in global climate and carbon cycling. The evidence for these changes includes stable isotope records that reveal prominent decreases in i 18 Oa ndi 13 C, suggesting a rise in Earth's surface temperature (\ufffd 4 i C) and a drop in net carbon output from the ocean and atmosphere. Concurrently, deep-sea carbonate records at several sites indicate a deepening of the calcite compensation depth (CCD). Here we investigate possible causes (e.g., increased volcanic degassing or decreased net organic burial) for these observations, but from a new perspective. The basic model employed is a modified version of GEOCARB III. However, we have coupled this well-known geochemical model to LOSCAR (Long-term Ocean-atmosphere Sediment CArbon cycle Reservoir model), which enables simulation of seawater carbonate chemistry, the CCD, and ocean i 13 C. We have also added a capacitor, in this case represented by gas hydrates, that can store and release 13 C-depleted carbon to and from the shallow geosphere over millions of years. We further consider accurate input data (e.g., i 13 C of carbonate) on a currently accepted timescale that spans an interval much longer than the perturbation. Several different scenarios are investigated with the goal of consistency amongst inferred changes in temperature, the CCD, and surface ocean and deep ocean i 13 C. The results strongly suggest that a decrease in net organic carbon burial drove carbon cycle changes during the late Paleocene and early Eocene, although an increase in volcanic activity might have contributed. Importantly, a drop in net organic carbon burial may represent increased oxidation of previously deposited organic carbon, such as stored in peat or gas hydrates. The model successfully recreates trends in Earth surface warming, as inferred from i 18 O records, the CCD, and i 13 C. At the moment, however, our coupled modeling effort cannot reproduce the magnitude of change in all these records collectively. Similar problems have arisen in simulations of short-term hyperthermal events during the early Paleogene (Paleocene-Eocene Thermal Maximum), suggesting one or more basic issues with data interpretation or geochemical modeling remain.", "keyphrases": ["carbon cycling", "early eocene", "ccd"]}
{"id": "paleo.000363", "title": "What nymphal morphology can tell us about parental investment -a group of cockroach hatchlings in Baltic amber documented by a multi-method approach", "abstract": "We describe a piece of Baltic amber, about 50 million years old, which contains a group of 13 small cockroach nymphs. These specimens were documented with different methods to explore the advantages and limitations of certain imaging techniques:\n(1) light-based methods, such as stereo-macro photography, composite imaging under polarised light, combined with virtual surface reconstruction, and (2) X-ray micro-computed tomography, processed as volume renderings and surface reconstructions. All nymphs within the amber piece are of the same size and do not exhibit any noticeable morphological variance. Their developmental state and the way in which they are arranged indicate that these nymphs represent hatchlings. Dictyopterans (including Mantodea and Blattodea with Isoptera as ingroup) exhibit a wide range of different types of social and brood care behaviour. The evolution of this complex set of characters has been addressed repeatedly in extant-based approaches, yet deep-time aspects of this evolutionary process have rarely been addressed. The specimens described here could represent a case of a group of blattodean nymphs hatching from an ootheca, which would represent the first fossil record of such a process, or even possibly provide the first indirect evidence of social behaviour in fossil non-termite dictyopterans, indicating that it was already developed 50 million years ago.", "keyphrases": ["morphology", "hatchling", "baltic amber", "nymph"]}
{"id": "paleo.000720", "title": "Evolutionary development of the cephalopod arm armature: a review", "abstract": "The cephalopod arm armature is certainly one of the most important morphological innovations responsible for the evolutionary success of the Cephalopoda. New palaeontological discoveries in the recent past afford to review and reassess origin and homology of suckers, sucker rings, hooks, and cirri. Since a priori character state reconstructions are still ambiguous, we suggest and discuss three different evolutionary scenarios. Each of them is based on the following assumptions: (1) Neocoleoidea uniting extant Decabrachia and Octobrachia is monophyletic (= proostracumbearing coleoids); (2) extinct Belemnitida and Diplobelida are stem decabrachians; (3) proostracum-less coleoids (Hematitida, Donovaniconida, Aulacoceratida) represent stem-neocoleoids; (4) Ammonoidea and Bactritoidea are stem coleoids. We consider a scenario where belemnoid hooks derived from primitive suckers as well-supported. Regarding belemnoid hooks and suckers as homologues implies that belemnoid, oegopsid, and probably ammonoid arm hooks arose through parallel evolution. Our conclusions challenge the widespread opinion, whereupon belemnoid hooks evolved de novo, and instead support earlier ideas formulated by Sigurd von Boletzky.", "keyphrases": ["cephalopod arm armature", "sucker", "arm hook"]}
{"id": "paleo.001962", "title": "A New Centrosaurine from the Late Cretaceous of Alberta, Canada, and the Evolution of Parietal Ornamentation in Horned Dinosaurs", "abstract": "In 1916, a centrosaurine dinosaur bonebed was excavated within the Campanian-aged deposits of what is now Dinosaur Provincial Park, Alberta, Canada. Specimens from this now-lost quarry, including two parietals, a squamosal, a skull missing the frill, and an incomplete dentary, were purchased by The Natural History Museum, London. The material was recently reprepared and identified herein as a previously unknown taxon, Spinops sternbergorum gen. et sp. nov. Based upon the available locality data and paleopalynology, the quarry lies in either the upper part of the Oldman Formation or the lower part of the Dinosaur Park Formation. The facial region of the partial skull is similar to putative mature specimens of Centrosaurus spp. and Styracosaurus albertensis, with short, rounded postorbital horncores and a large, erect nasal horncore. Parietal ornamentation is consistent on both known parietals and is unique among ceratopsids. Bilateral, procurved parietal hooks occupy the P1 (medial-most) position on the dorsal surface of the parietal and are very similar to those seen in Centrosaurus apertus. Epiparietals in the P2 or possibly P3 position (lateral to P1) manifest as extremely elongate, caudally directed spikes, unlike the condition in C. apertus, S. albertensis, or any other \u201cderived\u201d centrosaurine. Cladistic analysis suggests that S. sternbergorum is closely related to Centrosaurus and Styracosaurus. Historically, based upon the condition in Styracosaurus and related centrosaurines, it was assumed that the medial-most elongated spikes on centrosaurine parietals correspond to the P3 epiparietal position. The exception illustrated in the new taxon suggests that homologies of epiparietals among basal centrosaurines (e.g., Albertaceratops and Diabloceratops) and derived centrosaurines (e.g., Styracosaurus and \u201cpachyrhinosaurs\u201d) should be reconsidered. The medially-placed, caudally-directed \u201cP3\u201d process of basal centrosaurines may, in fact, be homologous with P2.", "keyphrases": ["centrosaurine", "alberta", "parietal ornamentation"]}
{"id": "10.1111/pala.12338", "title": "The diverse dietary profiles of MIS 3 cave bears from the Romanian Carpathians: insights from stable isotope (\u03b413C and \u03b415N) analysis", "abstract": "Late Pleistocene European cave bears (Ursus spelaeus) have been considered to be largely vegetarian, although stable isotope data (\u03b413C and \u03b415N values) from the Romanian Carpathians has suggested considerable dietary variation. Here we evaluate previous and additional adult cave bear isotopic data from four Marine Isotope Stage 3 (MIS 3) sites in the Carpathians. Pe\u015ftera Ur\u015filor (N = 35), Pe\u015ftera Cioclovina (N = 32), Pe\u015ftera Muierilor (N = 8), and Pe\u015ftera cu Oase (N = 72) provide both a dichotomy between samples suggesting vegetarian diets (from Cioclovina and Muierilor) and more omnivorous diets (from Ur\u015filor and Oase), and considerable isotopic variation within samples from each site. While an inference of a strictly vegetarian diet may apply to groups that lived in ecosystems which restricted the available animal protein for these large ursids, the within and between sample isotopic variation among the Carpathian cave bears indicates considerable flexibility in their sources of protein and hence in their dietary regimes. In addition, developmental assessment of Cioclovina isotopic profiles (neonates, juveniles, sub\u2010adults and adults) provides patterns of transfer of stable isotope signatures throughout immature life for both \u03b413C and \u03b415N (increase and decrease, respectively), whereas those from Ur\u015filor show little developmental shift.", "keyphrases": ["cave bear", "carpathians", "omnivorous diet"]}
{"id": "10.1029/2006GC001564", "title": "Foraminiferal Mg/Ca increase in the Caribbean during the Pliocene: Western Atlantic Warm Pool formation, salinity influence, or diagenetic overprint?", "abstract": "We constructed a high\u2010resolution Mg/Ca record on the planktonic foraminifer Globigerinoides sacculifer in order to explore the change in sea surface temperature (SST) due to the shoaling of the Isthmus of Panama as well as the impact of secondary factors like diagenesis and large salinity fluctuations. The study covers the latest Miocene and the early Pliocene (5.6\u20133.9 Ma) and was combined with \u03b418O to isolate changes in sea surface salinity (SSS). Before 4.5 Ma, SSTMg/Ca and SSS show moderate fluctuations, indicating a free exchange of surface ocean water masses between the Pacific and the Atlantic. The increase in \u03b418O after 4.5 Ma represents increasing salinities in the Caribbean due to the progressive closure of the Panamanian Gateway. The increase in Mg/Ca toward values of maximum 7 mmol/mol suggests that secondary influences have played a significant role. Evidence of crystalline overgrowths on the foraminiferal tests in correlation with aragonite, Sr/Ca, and productivity cyclicities indicates a diagenetic overprint on the foraminiferal tests. Laser ablation inductively coupled plasma\u2013mass spectrometry analyses, however, do not show significantly increased Mg/Ca ratios in the crystalline overgrowths, and neither do calculations based on pore water data conclusively result in significantly elevated Mg/Ca ratios in the crystalline overgrowths. Alternatively, the elevated Mg/Ca ratios might have been caused by salinity as the \u03b418O record of Site 1000 has been interpreted to represent large fluctuations in SSS, and cultivating experiments have shown an increase in Mg/Ca with increasing salinity. We conclude that the Mg/Ca record <4.5 Ma can only reliably be considered for paleoceanographical purposes when the minimum values, not showing any evidence of secondary influences, are used, resulting in a warming of central Caribbean surface water masses after 4.5 Ma of \u223c2\u00b0C.", "keyphrases": ["caribbean", "diagenetic overprint", "late miocene"]}
{"id": "paleo.001179", "title": "A lower jaw of Palaeoxonodon from the Middle Jurassic of the Isle of Skye, Scotland, sheds new light on the diversity of British stem therians", "abstract": "The Middle Jurassic was a key interval of mammalian evolutionary history that witnessed the diversification of the therian stem group. Great Britain has yielded a significant record of mammalian fossils from this interval, represented by numerous isolated jaws and teeth from the Bathonian of Oxfordshire and the Isle of Skye. This record captures a key period in early cladotherian evolution, with amphitheriids, peramurans and \u2018stem zatherians\u2019 displaying intermediate talonid morphologies that document the evolutionary assembly of tribosphenic molars. We present a mandible with near\u2010complete dentition from the late Bathonian (c. 167.4\u2013166.5 Ma) Kilmaluag Formation, near Elgol, Skye, representing the amphitheriid Palaeoxonodon ooliticus, previously known only from isolated teeth. The specimen sheds new light on the taxonomic diversity of British Middle Jurassic stem therians, as the morphological variation within the preserved tooth row encompasses that previously ascribed to three distinct species within two genera: Palaeoxonodon ooliticus, P. freemani and Kennetheridium leesi. Thus, both P. freemani and K. leesi are subjective junior synonyms of P. ooliticus. The dental formula of P. ooliticus (i4:c1:p5:m5) is intermediate between the primitively larger postcanine count (p5:m6\u20137) of Amphitherium and the reduced number in peramurans and tribosphenidans (p5:m3). Phylogenetic analyses of P. ooliticus generally confirm a close affinity with Amphitherium, but highlight the lack of strong empirical support for hypothesized patterns of divergences among early cladotherians.", "keyphrases": ["jaw", "palaeoxonodon", "early cladotherian", "phylogenetic analysis"]}
{"id": "10.1130/G20170.1", "title": "Drowning of the \u2212150 m reef off Hawaii: A casualty of global meltwater pulse 1A?", "abstract": "We present evidence that the drowning of the 2150 m coral reef around Hawaii was caused by rapid sea-level rise associated with meltwater pulse 1A (MWP-1A) during the last deglaciation. New U/Th and 14 C accelerator mass spectrometry dates, combined with reinterpretation of existing radiometric dates, constrain the age of the coral reef to 15.2-14.7 ka (U/Th age), indicating that reef growth persisted for 4.3 k.y. following the end of the Last Glacial Maximum at 19 ka. The drowning age of the reef is roughly synchronous with the onset of MWP-1A between 14.7 and 14.2 ka. Dates from coralline algal material range from 14 to 10 cal ka (calibrated radiocarbon age), 1-4 k.y. younger than the coral ages. A paleoenvironmental reconstruction incorporating all available radiometric dates, high-resolution bathymetry, dive observations, and coralgal paleobathymetry data indicates a dramatic rise in sea level around Hawaii ca. 14.7 ka. Paleowater depths over the reef crest increased rapidly above a critical depth (30-40 m), drowning the shallow reef-building Porites corals and causing a shift to deep- water coralline algal growth, preserved as a crust on the drowned reef crest.", "keyphrases": ["reef", "hawaii", "drowning"]}
{"id": "10.1002/ar.24046", "title": "Saws, Scissors, and Sharks: Late Paleozoic Experimentation with Symphyseal Dentition", "abstract": "Sharks of Late Paleozoic oceans evolved unique dentitions for catching and eating soft bodied prey. A diverse but poorly preserved clade, edestoids are noted for developing biting teeth at the midline of their jaws. Helicoprion has a continuously growing root to accommodate >100 crowns that spiraled on top of one another to form a symphyseal whorl supported and laterally braced within the lower jaw. Reconstruction of jaw mechanics shows that individual serrated crowns grasped, sliced, and pulled prey items into the esophagus. A new description and interpretation of Edestus provides insight into the anatomy and functional morphology of another specialized edestoid. Edestus has opposing curved blades of teeth that are segmented and shed with growth of the animal. Set on a long jaw the lower blade closes with a posterior motion, effectively slicing prey across multiple opposing serrated crowns. Further examples of symphyseal whorls among Edestoidae are provided from previously undescribed North American examples of Toxoprion, Campyloprion, Agassizodus, and Sinohelicoprion. The symphyseal dentition in edestoids is associated with a rigid jaw suspension and may have arisen in response to an increase in pelagic cephalopod prey during the Late Paleozoic. Anat Rec, 2018. \u00a9 2018 Wiley Periodicals, Inc. Anat Rec, 303:363\u2013376, 2020. \u00a9 2018 American Association for Anatomy", "keyphrases": ["symphyseal dentition", "crown", "low jaw"]}
{"id": "10.1146/annurev-earth-072619-060126", "title": "Splendid Innovation: The Extinct South American Native Ungulates", "abstract": "A remarkable diversity of plant-eating mammals known as South American native ungulates (SANUs) flourished in South America for most of the Cenozoic. Although some of these species likely filled ecological niches similar to those of modern hoofed mammals, others differed substantially from extant artiodactyls and perissodactyls in their skull and limb anatomy and probably also in their ecology. Notoungulates and litopterns were the longest-lived and most diverse SANU clades and survived into the Quaternary; astrapotheres went extinct in the late Miocene, whereas other SANU groups were restricted to the Paleogene. Neogene notoungulates were quite specialized in craniodental structure, but many were rather unspecialized postcranially; in contrast, litopterns evolved limb specializations early in their history while maintaining more conservative dentitions. In this article, we review the current understanding of SANU evolutionary relationships and paleoecology, provide an updated compilation of genus temporal ranges, and discuss possible directions for future research. \u25aa\u2002 South American native ungulates (SANUs) were a diverse, long-lived, and independent radiation of mammals into varied terrestrial plant-eater niches. \u25aa\u2002 We review origins, evolution, and paleoecology of the major SANU clades: Notoungulata, Litopterna, Astrapotheria, Xenungulata, and Pyrotheria. \u25aa\u2002 At their peak, during the Eocene and Oligocene, more than 40 genera of native ungulates inhabited South America at any one time. \u25aa\u2002 SANUs ranged from <1 kg to several tons and evolved many combinations of diet and locomotor adaptations not seen in living ungulates.", "keyphrases": ["sanu", "notoungulate", "litopterna", "late pleistocene", "evolutionary history"]}
{"id": "10.1017/S009483730001229X", "title": "Diversity changes in lycopsid and aquatic fern megaspores through geologic time", "abstract": "Quantitative data on lycopsid and aquatic fern megaspore taxa recovered from Carboniferous, Mesozoic, and Tertiary strata have been compiled in order to analyze the changes in diversity of the two groups of fossil plants that produced them. Numbers of species of lycopsid megaspores are similar in the Carboniferous and Mesozoic, whereas the diversity of megafossils is much lower in post-Paleozoic deposits. Our data suggest that lycopsids were more diverse in the Mesozoic than previously thought and that there is a preservational bias against the megafossils, because the plants were probably mainly herbaceous. Heterosporous aquatic ferns first appeared in the Neocomian and gradually diversified until the early Late Cretaceous, after which their numbers remained relatively stable, whereas the variety of lycopsids declined dramatically during the Late Cretaceous. These changes occurred at a time of rapid angiosperm diversification. The reduced diversity of the lycopsids may have been caused by the invasion of their aquatic and damp forest-floor habitats by heterosporous ferns and by aquatic and herbaceous angiosperms. These diversity changes do not seem to be directly related to the global events at the Cretaceous-Tertiary boundary, but the relatively few samples available and the resulting range truncation would make detection of such correlations difficult.", "keyphrases": ["lycopsid", "megaspore", "diversity change"]}
{"id": "10.1098/rspb.2013.0184", "title": "Large-scale phylogeny of chameleons suggests African origins and Eocene diversification", "abstract": "Oceanic dispersal has emerged as an important factor contributing to biogeographic patterns in numerous taxa. Chameleons are a clear example of this, as they are primarily found in Africa and Madagascar, but the age of the family is post-Gondwanan break-up. A Malagasy origin for the family has been suggested, yet this hypothesis has not been tested using modern biogeographic methods with a dated phylogeny. To examine competing hypotheses of African and Malagasy origins, we generated a dated phylogeny using between six and 13 genetic markers, for up to 174 taxa representing greater than 90 per cent of all named species. Using three different ancestral-state reconstruction methods (Bayesian and likelihood approaches), we show that the family most probably originated in Africa, with two separate oceanic dispersals to Madagascar during the Palaeocene and the Oligocene, when prevailing oceanic currents would have favoured eastward dispersal. Diversification of genus-level clades took place in the Eocene, and species-level diversification occurred primarily in the Oligocene. Plio-Pleistocene speciation is rare, resulting in a phylogeny dominated by palaeo-endemic species. We suggest that contraction and fragmentation of the Pan-African forest coupled to an increase in open habitats (savannah, grassland, heathland), since the Oligocene played a key role in diversification of this group through vicariance.", "keyphrases": ["phylogeny", "chameleon", "madagascar", "palaeocene", "eastward dispersal"]}
{"id": "paleo.012133", "title": "Widespread mermithid nematode parasitism of Cretaceous insects", "abstract": "Mermithid nematodes are obligate invertebrate parasites dating back to the Early Cretaceous. Their fossil record is sparse, especially before the Cenozoic, thus little is known about their early host associations. This study reports 16 new mermithids associated with their insect hosts from mid-Cretaceous Kachin amber, 12 of which include previously unknown hosts. These fossils indicate that mermithid parasitism of invertebrates was already widespread and played an important role in the mid-Cretaceous terrestrial ecosystem. Remarkably, three hosts (bristletails, barklice and perforissid planthoppers) were previously unknown to be parasitized by mermithids both past and present. Furthermore, our statistical analyses show that in contrast to their Cenozoic counterparts, Cretaceous nematodes including mermithids are more abundant in heterometabolous insect hosts. This result suggests that nematodes have not completely exploited the dominant Holometabola as their hosts until the Cenozoic. This study reveals what appears to be a vanished history of nematodes that parasitized Cretaceous insects.", "keyphrases": ["mermithid", "nematode", "cretaceous insect", "invertebrate"]}
{"id": "paleo.007467", "title": "First Evidence of Reproductive Adaptation to \u201cIsland Effect\u201d of a Dwarf Cretaceous Romanian Titanosaur, with Embryonic Integument In Ovo", "abstract": "Background The Cretaceous vertebrate assemblages of Romania are famous for geographically endemic dwarfed dinosaur taxa. We report the first complete egg clutches of a dwarf lithostrotian titanosaur, from Tote\u015fti, Romania, and its reproductive adaptation to the \u201cisland effect\u201d. Methodology/Findings The egg clutches were discovered in sequential sedimentary layers of the Maastrichtian S\u00e2npetru Formation, Tote\u015fti. The occurrence of 11 homogenous clutches in successive strata suggests philopatry by the same dinosaur species, which laid clutches averaging four \u223c12 cm diameters eggs. The eggs and eggshells display numerous characters shared with the positively identified material from egg-bearing level 4 of the Auca Mahuevo (Patagonia, Argentina) nemegtosaurid lithostrotian nesting site. Microscopic embryonic integument with bacterial evidences was recovered in one egg. The millimeter-size embryonic integument displays micron size dermal papillae implying an early embryological stage at the time of death, likely corresponding to early organogenesis before the skeleton formation. Conclusions/Significance The shared oological characters between the Ha\u0163eg specimens and their mainland relatives suggest a highly conservative reproductive template, while the nest decrease in egg numbers per clutch may reflect an adaptive trait to a smaller body size due to the \u201cisland effect\u201d. The combined presence of the lithostrotian egg and its embryo in the Early Cretaceous Gobi coupled with the oological similarities between the Ha\u0163eg and Auca Mahuevo oological material evidence that several titanosaur species migrated from Gondwana through the Ha\u0163eg Island before or during the Aptian/Albian. It also suggests that this island might have had episodic land bridges with the rest of the European archipelago and Asia deep into the Cretaceous.", "keyphrases": ["reproductive adaptation", "island effect", "embryonic integument", "egg", "auca mahuevo"]}
{"id": "10.1080/02724634.1995.10011259", "title": "Two new horned dinosaurs from the upper Cretaceous Two Medicine Formation of Montana; with a phylogenetic analysis of the Centrosaurinae (Ornithischia: Ceratopsidae)", "abstract": "ABSTRACT Two new ceratopsid dinosaurs, Einiosaurus procurvicornis and Achelousaurus horneri, are described from the Two Medicine Formation (Upper Cretaceous) of Montana. E. procurvicornis is known from three skulls and numerous cranial and postcranial elements from two bonebed assemblages. A. horneri is based on three skulls, one with associated postcranial elements. A phylogenetic review of the subfamily Centrosaurinae reveals two clades, one containing Centrosaurus and Styracosaurus and the other Pachyrhinosaurus plus the two new taxa from Montana. Diagnostic traits for resolving within-group relationships are found only in the skull roof in association with what appear to be secondary sexual characters, probably the result of sexual selection. In addition to illuminating the pattern of ceratopsian evolution, these taxa suggest an increased rate of evolution that may correlate with the late Campanian transgression of the Bearpaw Sea.", "keyphrases": ["montana", "centrosaurinae", "achelousaurus horneri"]}
{"id": "paleo.003786", "title": "Hypoanthraconaia: a new genus of non-marine bivalve molluscs from the Early Permian of Far East Russia", "abstract": "Early Permian continental deposits include a large number of localities containing anthracosiid-like nonmarine bivalves traditionally assigned to Anthraconaia Trueman and Weir, 1946, Palaeanodonta Amalitzky, 1895, and Palaeomutela Amalitzky, 1892. In most cases, these classifications are only tentative due to insufficient preservation in which the shells are missing their main characteristics: the ligament and the hinge. Non-marine bivalves from the Early Permian Upper Pospelovka Subformation of Russky Island (South Primorye, Far East Russia), described here as Hypoanthraconaia gen. nov., differ morphologically from the above genera by a set of external features including the initial shell, the mode of intersection of the growth lines with the dorsal margin, and the details of the sculpture. Hypoanthraconaia gen. nov. shows the most external similarity with ''atypical'' anthracosiid-like morphotypes of Anthraconaia that are widespread in the Late Pennsylvanian and Early Permian of eastern North America, and the Stephanian and Early Permian Lower Rotliegend of northwestern Europe. On this basis, the new genus is conventionally assigned to the family Naiaditidae Scarlato and Starobogatov, 1979. ", "keyphrases": ["new genus", "far east russia", "dorsal margin"]}
{"id": "10.1098/rspb.2010.1444", "title": "Spatial niche partitioning in dinosaurs from the latest cretaceous (Maastrichtian) of North America", "abstract": "We examine patterns of occurrence of associated dinosaur specimens (n = 343) from the North American Upper Cretaceous Hell Creek Formation and equivalent beds, by comparing their relative abundance in sandstone and mudstone. Ceratopsians preferentially occur in mudstone, whereas hadrosaurs and the small ornithopod Thescelosaurus show a strong association with sandstone. By contrast, the giant carnivore Tyrannosaurus rex shows no preferred association with either lithology. These lithologies are used as an indicator of environment of deposition, with sandstone generally representing river environments, and finer grained sediments typically representing floodplain environments. Given these patterns of occurrence, we argue that spatial niche partitioning helped reduce competition for resources between the herbivorous dinosaurs. Within coastal lowlands ceratopsians preferred habitats farther away from rivers, whereas hadrosaurs and Thescelosaurus preferred habitats in close proximity to rivers, and T. rex, the ecosystem's sole large carnivore, inhabited both palaeoenvironments. Spatial partitioning of the environment helps explain how several species of large herbivorous dinosaurs coexisted. This study emphasizes that different lithologies can preserve dramatically dissimilar vertebrate assemblages, even when deposited in close proximity and within a narrow window of time. The lithology in which fossils are preserved should be recorded as these data can provide unique insights into the palaeoecology of the animals they preserve.", "keyphrases": ["maastrichtian", "north america", "dinosaur specimen", "lithology"]}
{"id": "10.1017/S0016756812001057", "title": "A high-resolution, multiproxy stratigraphic analysis of the Devonian\u2013Carboniferous boundary sections in the Moravian Karst (Czech Republic) and a correlation with the Carnic Alps (Austria)", "abstract": "Abstract A multidisciplinary correlation of the Devonian\u2013Carboniferous (D\u2013C) boundary sections from the Moravian Karst (Czech Republic) and the Carnic Alps (Austria), based on conodont and foraminifer biostratigraphy, microfacies analysis, field gamma-ray spectroscopy (GRS), carbon isotopes and element geochemistry, is presented in this paper. The study is focused on the interval from the Middle Palmatolepis gracilis expansa Zone (Late Famennian) to the Siphonodella sandbergi Zone (Early Tournaisian). In Lesn\u00ed lom (Moravian Karst), a positive \u03b413C excursion in the Bisphatodus costatus \u2013 Protognathodus kockeli Interregnum from a distinct laminated carbonate horizon is correlated with a carbon isotope excursion from the Gr\u00fcne Schneid section of the Carnic Alps and is interpreted as the equivalent of the Hangenberg black shales and a local expression of the global Hangenberg Event sensu stricto. Higher up at both sections, a significant increase in the terrigenous input, which is inferred from the GRS signal and elevated concentrations of terrigenous elements (Si, Ti, Zr, Rb, Al, etc.), provides another correlation tieline and is interpreted as the equivalent of the Hangenberg sandstone. Both horizons are discussed in terms of relative sea-level fluctuations and palaeoceanographic changes. Recent studies show that conodont biostratigraphy is facing serious problems associated with the taxonomy of the first siphonodellids, their dependence on facies and discontinuous occurrences of protognathodids at the D\u2013C boundary. Therefore, the correlative potential of geochemical and petrophysical signatures is high and offers an alternative for the refining of the problematic biostratigraphic division of the D\u2013C boundary.", "keyphrases": ["boundary section", "moravian karst", "black shale"]}
{"id": "10.3140/bull.geosci.1856", "title": "Filling the gap in knowledge of early Miocene continental molluscs of southwest Europe: gastropods from Ribesalbes-Alcora Basin (Spain)", "abstract": "such as those of Vall\u00e9s-Pened\u00e9s, Ebro, Calatayud-Daroca, Teruel, Duero and Tajo, as well as smaller ones such as Cabriel, Fortuna, Guadix-Baza and Granada (Agust\u00ed 2018). Continental sediments of Aragonian age (end of the early Miocene to middle Miocene; mammal biozones MN4 to MN7/8) are represented in many of these basins (Agust\u00ed 2018). While mammal associations have been studied extensively in several palaeontological sites, the malacological record is comparatively poor documented. The few studies carried out on the malacological assemblages recorded in sediments today attributed to an Aragonian age are to some extent outdated (Vilanova y Piera 1859; Royo G\u00f3mez 1922, 1926, 1928; Jodot 1959). Also, many of sites and faunas documented in these works could not be precisely located. The available references accurately located and dated correspond to sites attributed to the middle Aragonian of the Tajo Basin (Truc 1977) and the upper Aragonian of the Duero Basin (Gonz\u00e1lez Delgado et al. 1986, Civis et al. 1989). The references from the early Aragonian are practically inexistent and correspond to isolated cites or recent multidisciplinary studies in the Ribesalbes-Alcora Basin (Pe\u00f1alver et al. 2016, \u00c1lvarezParra et al. 2021). In line with the above, the available data on the mala cological content of the sediments of the Ribesalbes-Alcora Basin (Fig. 1A) are mostly old and very scarce. The first one corresponds to Vilanova y Piera (1859) who studied the materials in the \u201cBalsa de Fanzara\u02ee (the classical name for the Cenozoic sediments of the basin) and the nearby area of Alcal\u00e1. He cited the generic presence of \u201clymneas\u02ee, \u201cplanorbis\u201d and \u201chelices\u02ee (Vilanova y Piera 1859: p. 44), and more specifically a single specimen of Planorbis rotundatus Brongniart, 1810 from the \u201cBalsa de Fanzara\u201d, which is shown on a plate alongside with four species belonging to the Alcal\u00e1 area. Royo G\u00f3mez (1922) included a brief reference to the sediments of the studied area correcting the determination of Planorbis rotundatus to", "keyphrases": ["early miocene", "ribesalbes-alcora basin", "mollusk group", "insectivore"]}
{"id": "10.1666/11-020.1", "title": "Systematics and Evolution of Paleozoic And Mesozoic Damselfly-Like Odonatoptera of the \u2018Protozygopteran\u2019 Grade", "abstract": "Abstract The Paleozoic to Mesozoic grade \u2018Protozygoptera\u2019 is revised. It appears to be composed of two main lineages, namely the superfamily Permagrionoidea, and the Archizygoptera. The latter taxon forms a monophyletic group together with Panodonata (\u200a=\u200acrown-Odonata plus their closest stem-relatives). Therefore, the \u2018Protozygoptera\u2019 as previously understood is paraphyletic. Diagnostic characters of the \u2018Protozygoptera\u2019, Permagrionoidea, and Archizygoptera are re-evaluated. The Permolestidae is considered as a junior synonym of the Permagrionidae. The following new taxa are described: Permolestes sheimogorai new species, Permolestes soyanaiensis new species, Epilestes angustapterix new species, Solikamptilon pectinatus new species (all in Permagrionidae); Lodeviidae new family (for Lodevia); Luiseiidae new family (including Luiseia breviata new genus and species); Kennedya azari new species, Kennedya pritykinae new species, Kennedya ivensis new species, Progoneura grimaldii new species (all in Kennedyidae); Engellestes chekardensis new genus and species (in Bakteniidae); and Azaroneura permiana new genus and species (in Voltzialestidae). The Kaltanoneuridae and Oboraneuridae are revised. The evolution of protozygopteran Odonatoptera during the transition from the Permian to the Triassic is discussed. The larger taxa of the permagrionoid lineage apparently did not cross through the Permian\u2013Triassic boundary, unlike the more gracile Archizygoptera. This last group shows a remarkable longevity from the late Carboniferous to the Early Cretaceous. It also presents a great taxonomic and morphological stability, with genera ranging from the Permian to the Triassic, and a wing venation pattern nearly unchanged from the late Carboniferous to the Late Triassic. The mass extinction at the end of the Permian period seemingly had a minor effect on these tiny and delicate insects.", "keyphrases": ["paleozoic", "archizygoptera", "panodonata"]}
{"id": "10.1130/G23139A.1", "title": "Chronology of Miocene-Pliocene Deposits at Split Mountain Gorge, Southern California: A Record of Regional Tectonics and Colorado River Evolution", "abstract": "Late Miocene to early Pliocene deposits at Split Mountain Gorge, California, preserve a record of basinal response to changes in regional tectonics, paleogeography, and evolution of the Colorado River. The base of the Elephant Trees Formation, magnetostratigraphically dated as 8.1 \u00b1 0.4 Ma, provides the earliest well-dated record of extension in the southwestern Salton Trough. The oldest marine sediments are ca. 6.3 Ma. The nearly synchronous timing of marine incursion in the Salton Trough and northern Gulf of California region supports a model for localization of Pacifi c\u2010North America plate motion in the Gulf ca. 6 Ma. The fi rst appearance of Colorado River sand at the Miocene-Pliocene boundary (5.33 Ma) suggests rapid propagation of the river to the Salton Trough, and supports a lake-spillover hypothesis for initiation of the lower Colorado River.", "keyphrases": ["split mountain gorge", "colorado river sand", "miocene-pliocene boundary"]}
{"id": "paleo.005278", "title": "Giant lizards occupied herbivorous mammalian ecospace during the Paleogene greenhouse in Southeast Asia", "abstract": "Mammals dominate modern terrestrial herbivore ecosystems, whereas extant herbivorous reptiles are limited in diversity and body size. The evolution of reptile herbivory and its relationship to mammalian diversification is poorly understood with respect to climate and the roles of predation pressure and competition for food resources. Here, we describe a giant fossil acrodontan lizard recovered with a diverse mammal assemblage from the late middle Eocene Pondaung Formation of Myanmar, which provides a historical test of factors controlling body size in herbivorous squamates. We infer a predominately herbivorous feeding ecology for the new acrodontan based on dental anatomy, phylogenetic relationships and body size. Ranking body masses for Pondaung Formation vertebrates indicates that the lizard occupied a size niche among the larger herbivores and was larger than most carnivorous mammals. Paleotemperature estimates of Pondaung Formation environments based on the body size of the new lizard are approximately 2\u20135\u00b0C higher than modern. These results indicate that competitive exclusion and predation by mammals did not restrict body size evolution in these herbivorous squamates, and elevated temperatures relative to modern climates during the Paleogene greenhouse may have resulted in the evolution of gigantism through elevated poikilothermic metabolic rates and in response to increases in floral productivity.", "keyphrases": ["lizard", "paleogene greenhouse", "body size"]}
{"id": "10.1098/rsif.2016.0399", "title": "Mechanical modelling of tooth wear", "abstract": "Different diets wear teeth in different ways and generate distinguishable wear and microwear patterns that have long been the basis of palaeodiet reconstructions. Little experimental research has been performed to study them together. Here, we show that an artificial mechanical masticator, a chewing machine, occluding real horse teeth in continuous simulated chewing (of 100 000 chewing cycles) is capable of replicating microscopic wear features and gross wear on teeth that resemble wear in specimens collected from nature. Simulating pure attrition (chewing without food) and four plant material diets of different abrasives content (at n = 5 tooth pairs per group), we detected differences in microscopic wear features by stereomicroscopy of the chewing surface in the number and quality of pits and scratches that were not always as expected. Using computed tomography scanning in one tooth per diet, absolute wear was quantified as the mean height change after the simulated chewing. Absolute wear increased with diet abrasiveness, originating from phytoliths and grit. In combination, our findings highlight that differences in actual dental tissue loss can occur at similar microwear patterns, cautioning against a direct transformation of microwear results into predictions about diet or tooth wear rate.", "keyphrases": ["tooth wear", "experimental research", "grit"]}
{"id": "10.1046/j.1366-9516.2001.00117.x", "title": "Cenozoic environmental change in South America as indicated by mammalian body size distributions (cenograms)", "abstract": "A cenogram is a rank\u2010ordered body size distribution of non\u2010predatory terrestrial mammal species within a community. Studies of cenograms for modern faunas have shown that certain quantifiable attributes of cenograms are correlated with environmental variables such as rainfall and vegetation structure. Based on these correlations, cenograms of fossil communities have been used to infer palaeoenvironments and palaeoenvironmental variables. The present study uses cenogram statistics to interpret palaeoenvironmental conditions for eight Cenozoic South American mammal faunas, ranging from Eocene to Pleistocene in age. Body sizes for fossil taxa were taken either from the literature or were estimated using regressions of body size on molar length (or femoral bicondylar width) for modern mammals. Cenogram statistics are calculated for the eight fossil faunas and compared to similar statistics calculated for 16 modern South American mammal faunas, allowing palaeoenvironmental interpretations to be made. The palaeoenvironmental interpretations based on cenogram analyses sometimes support and sometimes contradict interpretations based on herbivore craniodental morphology (e.g. levels of hypsodonty). Simulations of expected errors in body size estimates for fossil taxa suggest that the discrepancies do not result primarily from erroneous body size estimates. It is possible that some of the incongruity in interpretations results from certain non\u2010analogue attributes of South American faunas during much of the Cenozoic (e.g. the relatively depauperate mammalian predator diversity prior to the Great American Biotic Interchange).", "keyphrases": ["body size distribution", "cenogram", "regression", "bicondylar width"]}
{"id": "10.1111/gcb.12426", "title": "Elevation\u2010induced climate change as a dominant factor causing the late Miocene C4 plant expansion in the Himalayan foreland", "abstract": "During the late Miocene, a dramatic global expansion of C4 plant distribution occurred with broad spatial and temporal variations. Although the event is well documented, whether subsequent expansions were caused by a decreased atmospheric CO2 concentration or climate change is a contentious issue. In this study, we used an improved inverse vegetation modeling approach that accounts for the physiological responses of C3 and C4 plants to quantitatively reconstruct the paleoclimate in the Siwalik of Nepal based on pollen and carbon isotope data. We also studied the sensitivity of the C3 and C4 plants to changes in the climate and the atmospheric CO2 concentration. We suggest that the expansion of the C4 plant distribution during the late Miocene may have been primarily triggered by regional aridification and temperature increases. The expansion was unlikely caused by reduced CO2 levels alone. Our findings suggest that this abrupt ecological shift mainly resulted from climate changes related to the decreased elevation of the Himalayan foreland.", "keyphrases": ["climate change", "himalayan foreland", "deciduous forest taxa", "plant megafossil evidence", "vegetation shift"]}
{"id": "paleo.007163", "title": "Minimum convex hull mass estimations of complete mounted skeletons", "abstract": "Body mass is a critical parameter used to constrain biomechanical and physiological traits of organisms. Volumetric methods are becoming more common as techniques for estimating the body masses of fossil vertebrates. However, they are often accused of excessive subjective input when estimating the thickness of missing soft tissue. Here, we demonstrate an alternative approach where a minimum convex hull is derived mathematically from the point cloud generated by laser-scanning mounted skeletons. This has the advantage of requiring minimal user intervention and is thus more objective and far quicker. We test this method on 14 relatively large-bodied mammalian skeletons and demonstrate that it consistently underestimates body mass by 21 per cent with minimal scatter around the regression line. We therefore suggest that it is a robust method of estimating body mass where a mounted skeletal reconstruction is available and demonstrate its usage to predict the body mass of one of the largest, relatively complete sauropod dinosaurs: Giraffatitan brancai (previously Brachiosaurus) as 23200 kg.", "keyphrases": ["mounted skeleton", "alternative approach", "body mass estimation", "convex hull volume"]}
{"id": "10.1029/2001pa000730", "title": "Impact of a Tethyan circumglobal passage on ocean heat transport and \u201cequable\u201d climates", "abstract": "[1]\u00a0The presence of low-latitude circumglobal passage from the late Jurassic (\u223c160 Ma) through the Miocene (\u223c14 Ma) provides a possible mechanism for increased poleward ocean heat transport during periods of warm climate and may help explain low meridional temperature gradients of the past. Experiments using an ocean general circulation model (GCM) with an energy-balance atmosphere and idealized bathymetry reveal that, like the modern Drake Passage, a circumglobal Tethyan Passage might have induced high rates of wind-driven upwelling of relatively cold and deep water, but at low latitudes. With no change in radiative forcing, a low-latitude circumglobal passage increases simulated northern high-latitude temperatures by 3\u00b0\u20137\u00b0C, while tropical temperatures cool by up to 2\u00b0C relative to a scenario with solid meridional boundaries. Combining this mechanism of heat transport with increased radiative forcing allows substantial warming of northern high latitudes by 7\u00b0\u201311\u00b0C, while tropical temperatures remain within 3\u00b0C of present-day temperatures.", "keyphrases": ["ocean heat transport", "warming", "high latitude"]}
{"id": "10.1080/10420940.2017.1337011", "title": "A Paleopolar Dinosaur Track Site in the Cretaceous (Maastrichtian) Prince Creek Formation of Arctic Alaska: Track Characteristics and Probable Trackmakers", "abstract": "ABSTRACT For the first time a dinosaur track site is identified in Maastrichtian paleopolar coastal plain deposits of the Prince Creek Formation (PCF) along the Colville River, North Slope of Alaska. Tracks were made and preserved by trampling of an ash-covered swamp margin, subsequent filling of tracks with alluvium from nearby rivers, and modification of sediments by pedogensis. Tracks are grouped into three classes based on track width and depth, with the largest tracks (>800 mm wide) recording overstepping by multiple individuals. As no bedding plane views of the tracks are present, the true shapes of the tracks were not available and, thus, a high probability of identification is not achievable. The tracks can be interpreted, however, using hypothetical-deductive reasoning by integrating paleontological and ichnological data from local and regional outcrops. The tracks likely represent the presence of hadrosaurs based on the overwhelming percentage of hadrosaur fossils that comprise nearby bonebeds, dominated by juvenile hadrosaurs (\u223c 99%); to date no adult hadrosaur bone has been documented in the PCF. This interpretation is also supported by comparison of PCF hadrosaur track dimensions to exquisitely preserved (three-dimensional tracks with skin impressions) trackways of the coeval Cantwell Formation in Denali National Park (DENA), central Alaska. PCF track size dimensions, in comparison to DENA tracks, also represent a series of growth stages including both juvenile and adult hadrosaurs, and indicate that multiple generations and sizes of individuals lived and traveled together on the Arctic Alaska coastal plain. This is the first evidence for adult hadrosaurs in the PCF. This track site also preserves the highest latitude Maastrichtian footprints known.", "keyphrases": ["track", "maastrichtian", "prince creek formation", "arctic alaska", "colville river"]}
{"id": "10.1371/journal.pone.0146825", "title": "Was Frozen Mammoth or Giant Ground Sloth Served for Dinner at The Explorers Club?", "abstract": "Accounts of woolly mammoths (Mammuthus primigenius) preserved so well in ice that their meat is still edible have a long history of intriguing the public and influencing paleontological thought on Quaternary extinctions and climate, with some scientists resorting to catastrophism to explain the instantaneous freezing necessary to preserve edible meat. Famously, members of The Explorers Club purportedly dined on frozen mammoth from Alaska, USA, in 1951. This event, well received by the press and general public, became an enduring legend for the Club and popularized the notorious annual tradition of serving rare and exotic food at Club dinners that continues to this day. The Yale Peabody Museum holds a sample of meat preserved from the 1951 meal, interestingly labeled as a South American giant ground sloth (Megatherium), not mammoth. We sequenced a fragment of the mitochondrial cytochrome-b gene and studied archival material to verify its identity, which if genuine, would extend the range of Megatherium over 600% and alter our views on ground sloth evolution. Our results indicate that the meat was not mammoth or Megatherium but green sea turtle (Chelonia mydas). The prehistoric dinner was likely an elaborate publicity stunt. Our study emphasizes the value of museums collecting and curating voucher specimens, particularly those used for evidence of extraordinary claims.", "keyphrases": ["frozen mammoth", "explorers club", "catastrophism"]}
{"id": "paleo.012442", "title": "Acheulean technology and landscape use at Dawadmi, central Arabia", "abstract": "Despite occupying a central geographic position, investigations of hominin populations in the Arabian Peninsula during the Lower Palaeolithic period are rare. The colonization of Eurasia below 55 degrees latitude indicates the success of the genus Homo in the Early and Middle Pleistocene, but the extent to which these hominins were capable of innovative and novel behavioural adaptations to engage with mid-latitude environments is unclear. Here we describe new field investigations at the Saffaqah locality (206\u201376) near Dawadmi, in central Arabia that aim to establish how hominins adapted to this region. The site is located in the interior of Arabia over 500 km from both the Red Sea and the Gulf, and at the headwaters of two major extinct river systems that were likely used by Acheulean hominins to cross the Peninsula. Saffaqah is one of the largest Acheulean sites in Arabia with nearly a million artefacts estimated to occur on the surface, and it is also the first to yield stratified deposits containing abundant artefacts. It is situated in the unusual setting of a dense and well-preserved landscape of Acheulean localities, with sites and isolated artefacts occurring regularly for tens of kilometres in every direction. We describe both previous and recent excavations at Saffaqah and its large lithic assemblage. We analyse thousands of artefacts from excavated and surface contexts, including giant andesite cores and flakes, smaller cores and retouched artefacts, as well as handaxes and cleavers. Technological assessment of stratified lithics and those from systematic survey, enable the reconstruction of stone tool life histories. The Acheulean hominins at Dawadmi were strong and skilful, with their adaptation evidently successful for some time. However, these biface-makers were also technologically conservative, and used least-effort strategies of resource procurement and tool transport. Ultimately, central Arabia was depopulated, likely in the face of environmental deterioration in the form of increasing aridity.", "keyphrases": ["landscape", "dawadmi", "central arabia"]}
{"id": "paleo.000335", "title": "A new wing skeleton of the Jehol tapejarid Sinopterus and its implications for ontogeny and paleoecology of the Tapejaridae", "abstract": "The tapejarid pterosaurs flourished in the Jehol Biota with an abundance of immature individuals and a rarity of individuals at skeletal maturity. Most of these individuals plot well on an ontogenetic series based on the proportions of limb elements, but this has lacked histological evidence until now. Here, a new wing skeleton of Sinopterus was thin-sectioned to provide the first histological data about the ontogeny of the Jehol tapejarids. Histologically, the new specimen is an immature individual at a late juvenile stage prior to sexual maturity. It is grouped with medium-sized and medium-crested individuals, which are distinct from the small-sized and crestless individuals as well as the rare large-sized and large-crested individuals at skeletal maturity, supporting the presence of the premaxillary crest as an ontogenetic feature in the Jehol tapejarids. Furthermore, this histology indicates that the largest skeletally immature individuals might have reached the sexual maturity. Enigmatically, there is a size gap between sexual and skeletal maturity, which is at about 79% of the large size, implying a ontogenetic strategy comparable with Pteranodon and possibly with the Brazilian tapejarid Caiuajara. This size gap is consistent with lack of the larger sexually mature individuals in the Jehol Biota, which is hypothesized to be a migratory habitat for the Jehol tapejarids.", "keyphrases": ["new wing skeleton", "jehol tapejarid", "ontogeny"]}
{"id": "paleo.005892", "title": "Juvenile spinosaurs (Theropoda: Spinosauridae) from the middle Cretaceous of Morocco and implications for spinosaur ecology", "abstract": "The Spinosauridae is a specialised clade of theropod dinosaurs known from the Berriasian to the Cenomanian of Africa, South America, Europe and Asia. Spinosaurs were unusual among non-avian dinosaurs in exploiting a piscivorous niche within riverine and estuarine habitats, and they include the largest known theropod. Although fossils of giant spinosaurs are increasingly well-represented in the fossil record, little juvenile material has been described. Here, we describe new examples of juvenile spinosaurines from the middle Cretaceous (Cenomanian) Kem Kem beds of Morocco. The fossils include material from a range of sizes and are relatively common within the Kem Kem deposits, suggesting that juveniles exploited the same semiaquatic niche as the adults throughout ontogeny. This implies that the Cenomanian delta habitats supported an age-inclusive population of spinosaurs that was neither geographically or environmentally separated, though some ecological separation between juveniles and adults is likely based on the large variation in size. Bones or teeth of very small (<2 m) spinosaurs have not been found, however. This could represent a taphonomic bias, or potentially an ecological signal that the earliest ontogenetic stages inhabited distinct environments. Skeletal remains include individuals referable to Sigilmassasaurus brevicollis and a second spinosaurine taxon. Consistent with this, we also identify two distinct cranial morphs of Spinosauridae present within the Kem Kem, supporting previous recognition of distinct taxa in the assemblage.", "keyphrases": ["spinosaur", "spinosauridae", "non-avian dinosaur", "juvenile material"]}
{"id": "paleo.003969", "title": "A Jurassic stem pleurodire sheds light on the functional origin of neck retraction in turtles", "abstract": "Modern turtles are composed of two monophyletic groups, notably diagnosed by divergent neck retraction mechanisms. Pleurodires (side-necked turtles) bend their neck sideways and protect their head under the anterior margin of the carapace. Cryptodires (hidden-necked turtles) withdraw their neck and head in the vertical plane between the shoulder girdles. These two mechanisms of neck retraction appeared independently in the two lineages and are usually assumed to have evolved for protective reasons. Here we describe the neck of Platychelys oberndorferi, a Late Jurassic early stem pleurodire, and find remarkable convergent morphological and functional similarities with modern cryptodires. Partial vertical neck retraction in this taxon is interpreted to have enabled fast forward projection of the head during underwater prey capture and offers a likely explanation to the functional origin of neck retraction in modern cryptodires. Complete head withdrawal for protection may therefore have resulted from an exaptation in that group.", "keyphrases": ["jurassic", "functional origin", "neck retraction", "turtle", "platychelys oberndorferi"]}
{"id": "paleo.002277", "title": "The ammonite septum is not an adaptation to deep water: re-evaluating a centuries-old idea", "abstract": "The shells of ammonoid cephalopods are among the most recognizable fossils, whose fractally folded, internal walls (septa) have inspired many hypotheses on their adaptive value. The enduring explanation for their iterative evolution is that they strengthen the shell against pressure at increasing water depths. The fossil record does not definitively support this idea and much of the theoretical mechanical work behind it has suffered from inaccurate testing geometries and conflicting results. By using a different set of mathematical methods compared with previous studies, I generate a system of finite-element models that explore how different parameters affect the shell's response to water pressure. Increasing the number of initial folds of the septa ultimately has little to no effect on the resulting stress in the shell wall or the septum itself. The introduction of higher-order folds does reduce the tensile stress in the shell wall; however, this is coupled with a higher rate of increase of tensile stress in the septum itself. These results reveal that the increase in complexity should not be expected to have a significant effect on the shell's strength and suggests that the evolution of ammonitic septa does not reflect a persistent trend towards deeper-water habitats.", "keyphrases": ["septum", "idea", "pressure"]}
{"id": "10.1017/S0016756817000279", "title": "Appendages of an early Cambrian metadoxidid trilobite from Yunnan, SW China support mandibulate affinities of trilobites and artiopods", "abstract": "Abstract Appendage anatomy contributes crucial data for understanding the evolution and ecology of Euarthropoda. The Palaeozoic trilobites show a great diversity of exoskeletons in the fossil record. However, soft parts, especially appendages, have only been discovered from a few trilobite species. Here we report extraordinarily preserved appendages in the trilobite species Hongshiyanaspis yiliangensis Zhang & Lin in Zhang et al. 1980 (Redlichiida, Metadoxididae) from a single mudstone layer of the Xiazhuang fossil assemblage within the Hongjingshao Formation (Cambrian Series 2, Stage 3) near Kunming, Yunnan, SW China. The appendages exhibit the common architecture revealed by other trilobites and artiopods by consisting of a pair of uniramous antennae followed by a series of paired homonomous biramous limbs. The antennae in holaspid individuals comprise up to 27 spinous podomeres and their ontogeny occurs by lengthening of the podomeres. The post-antennal biramous limbs are similar to those in other polymerid trilobites and artiopods by having a single-segmented protopodite and an endopodite comprising seven segments, but possess a unique wide tripartite exopodite with long setae. Sophisticated appendage anatomy, including the body\u2013limb junction, fine setae, putative muscle bundles and duct-type tissues, are also revealed. Appendages of trilobites, artiopods and other upper stem-group euarthropods are compared and summarized. The H. yiliangensis appendages highlight the high morphological disparity of exopodites and the conservativeness of endopodites in trilobites and artiopods. This morphological pattern, together with similar body patterning seen in crustaceans but not in chelicerates, supports the mandibulate affinities of trilobites and at least some artiopods.", "keyphrases": ["trilobite", "mandibulate affinity", "euarthropod"]}
{"id": "10.1080/14772019.2012.691559", "title": "Osteology of Eubiodectes libanicus (Pictet & Humbert, 1866) and some other ichthyodectiformes (Teleostei): phylogenetic implications", "abstract": "The osteology of the ichthyodectiform Eubiodectes libanicus (Pictet & Humbert, 1866) from the Cenomanian of Lebanon is described on the basis of acid-prepared specimens. For comparative purposes, the osteology of other putative ichthyodectiforms is described or discussed. We focus on the description of hitherto poorly described species such as Chiromystus mawsoni Cope, 1885, Ghrisichthys bardacki (Cavin, 1997a), \u2018Saurodon' intermedius (Newton, 1878) and Thrissops sp. from Kimmeridge, England. Sixty-nine morphological characters are defined and analysed to infer the phylogenetic relationships within ichthyodectiforms. The main results are: (1) exclusion of Ascalabothrissops and Pachythrissops from the ichthyodectiforms; (2) redesignation of \u2018Ichthyodectes' bardacki, from the Turonian of Morocco, to Ghrisichthys gen. nov.; (3) resolution of a monophyletic family Cladocyclidae grouping mid-Cretaceous ichthyodectiforms that lived mainly along the southern margin of Tethys (Chirocentrites, Cladocyclus, Eubiodectes, Chiromystus); (4) resolution of a Late Cretaceous family Ichthyodectidae containing Ichthyodectes, Ghrisichthys and Xiphactinus from mid-northern latitude seas; and (5) a better resolved Late Cretaceous family Saurodontidae in the northern hemisphere, that includes the genus Gillicus.", "keyphrases": ["pictet", "ichthyodectiform", "osteology"]}
{"id": "paleo.000224", "title": "Inference of facultative mobility in the enigmatic Ediacaran organism Parvancorina", "abstract": "Establishing how Ediacaran organisms moved and fed is critical to deciphering their ecological and evolutionary significance, but has long been confounded by their non-analogue body plans. Here, we use computational fluid dynamics to quantitatively analyse water flow around the Ediacaran taxon Parvancorina, thereby testing between competing models for feeding mode and mobility. The results show that flow was not distributed evenly across the organism, but was directed towards localized areas; this allows us to reject osmotrophy, and instead supports either suspension feeding or detritivory. Moreover, the patterns of recirculating flow differ substantially with orientation to the current, suggesting that if Parvancorina was a suspension feeder, it would have been most efficient if it was able to re-orient itself with respect to current direction, and thus ensure flow was directed towards feeding structures. Our simulations also demonstrate that the amount of drag varied with orientation, indicating that Parvancorina would have greatly benefited from adjusting its position to minimize drag. Inference of facultative mobility in Parvancorina suggests that Ediacaran benthic ecosystems might have possessed a higher proportion of mobile taxa than currently appreciated from trace fossil studies. Furthermore, this inference of movement suggests the presence of musculature or appendages that are not preserved in fossils, but which would noneltheless support a bilaterian affinity for Parvancorina.", "keyphrases": ["facultative mobility", "osmotrophy", "suspension feeding", "inference"]}
{"id": "10.1111/j.1472-4669.2012.00332.x", "title": "Thermally\u2010induced structural and chemical alteration of organic\u2010walled microfossils: an experimental approach to understanding fossil preservation in metasediments", "abstract": "The identification and confirmation of bona fide Archean\u2013Paleoproterozoic microfossils can prove to be a challenging task, further compounded by diagenetic and metamorphic histories. While structures of likely biological origin are not uncommon in Precambrian rocks, the search for early fossil life has been disproportionately focused on lesser thermally altered rocks, typically greenschist or lower\u2010grade metamorphism. Recently, however, an increasing number of inferred micro\u2010 and macrofossils have been reported from higher\u2010grade metasediments, prompting us to experimentally test and quantify the preservability of organic\u2010walled microfossils over varying durations of controlled heating and under two differing redox conditions. Because of their relatively low\u2010intensity natural thermal alteration, acritarchs from the Mesoproterozoic Ruyang Group were chosen as subjects for experimental heating at approximately 500\u00b0C, with durations ranging from 1 to 250\u2003days and in both oxic (normal present day conditions) and anoxic conditions. Upon extraction, the opacity, reflectivity, color, microchemistry, and microstructures of the heated acritarchs were characterized using optic microscopy, scanning electron microscopy, Raman spectroscopy, and X\u2010ray photoelectron spectroscopy. The results differ for acritarchs prepared under oxic vs. anoxic conditions, with the anoxic replicates surviving experimental heating longer and retaining biological morphologies better, despite an increasing degree of carbonization with continuous heating. Conversely, the oxic replicates show aggressive degradation. In conjunction with fossils from high\u2010grade metasediments, our data illustrate the preservational potential of organic\u2010walled microfossils subjected to metamorphism in reducing conditions, offer insights into the search for microfossils in metasediments, and help to elucidate the influence of time on the carbonization/graphitization processes during thermal alteration.", "keyphrases": ["alteration", "organic\u2010walled microfossil", "metasediment", "redox condition", "laboratory experiment"]}
{"id": "10.1002/spp2.1401", "title": "The first Silurian trilobite with three\u2010dimensionally preserved soft parts\u00a0reveals novel appendage morphology", "abstract": "The first Silurian trilobite known with soft parts preserved, a Dalmanites species, is described from the Herefordshire Lagerst\u00e4tte. Biramous appendages and much of the alimentary system are evident. High\u2010fidelity three\u2010dimensional preservation reveals a novel arrangement of the exopod, in which successive filaments are connected by a presumed membrane. This morphology explains a misinterpretation of the exopod as supporting spiral structures, originally reported nearly 150 years ago. Comparison with other trilobite limbs indicates that the exopod morphology of Dalmanites is present in other members of Phacopida. The function of the exopod is considered to be primarily respiratory.", "keyphrases": ["silurian trilobite", "soft part", "morphology", "filament"]}
{"id": "10.1126/science.aba7096", "title": "Phasing of millennial-scale climate variability in the Pacific and Atlantic Oceans", "abstract": "Calving cousins Walczak et al. report that increases in Pacific Ocean ventilation and periods of rapid production of icebergs from the Cordilleran Ice Sheet during the last glacial period preceded episodic iceberg discharges into the Atlantic Ocean (see the Perspective by Jaeger and Shevenell). Marine sediments from the Gulf of Alaska show that increases in vertical mixing of the ocean there correspond with intense iceberg calving from the ice sheet that covered much of high-latitude western North America and that these changes occurred before the analogous Heinrich events in the North Atlantic. Thus, these Pacific climate system reorganizations may have been an early part of a cascade of dynamic climate events with global repercussions. Science, this issue p. 716; see also p. 662 Pacific iceberg discharge events preceded their Atlantic counterparts during the last glacial period. New radiocarbon and sedimentological results from the Gulf of Alaska document recurrent millennial-scale episodes of reorganized Pacific Ocean ventilation synchronous with rapid Cordilleran Ice Sheet discharge, indicating close coupling of ice-ocean dynamics spanning the past 42,000 years. Ventilation of the intermediate-depth North Pacific tracks strength of the Asian monsoon, supporting a role for moisture and heat transport from low latitudes in North Pacific paleoclimate. Changes in carbon-14 age of intermediate waters are in phase with peaks in Cordilleran ice-rafted debris delivery, and both consistently precede ice discharge events from the Laurentide Ice Sheet, known as Heinrich events. This timing precludes an Atlantic trigger for Cordilleran Ice Sheet retreat and instead implicates the Pacific as an early part of a cascade of dynamic climate events with global impact.", "keyphrases": ["pacific", "pacific ocean ventilation", "millennial-scale episode"]}
{"id": "paleo.002882", "title": "Asmodochelys parhami, a new fossil marine turtle from the Campanian Demopolis Chalk and the stratigraphic congruence of competing marine turtle phylogenies", "abstract": "Resolving the phylogeny of sea turtles is uniquely challenging given the high potential for the unification of convergent lineages due to systematic homoplasy. Equivocal reconstructions of marine turtle evolution subsequently inhibit efforts to establish fossil calibrations for molecular divergence estimates and prevent the accurate reconciliation of biogeographic or palaeoclimatic data with phylogenetic hypotheses. Here we describe a new genus and species of marine turtle, Asmodochelys parhami, from the Upper Campanian Demopolis Chalk of Alabama and Mississippi, USA represented by three partial shells. Phylogenetic analysis shows that A. parhami belongs to the ctenochelyids, an extinct group that shares characteristics with both pan-chelonioids and pan-cheloniids. In addition to supporting Ctenochelyidae as a sister taxon of Chelonioidea, our analysis places Protostegidae outside of the Chelonioidea crown group and recovers Allopleuron hofmanni as a stem dermochelyid. Gap excess ratio (GER) results indicate a strong stratigraphic congruence of our phylogenetic hypothesis; however, the highest GER value is associated with the phylogenetic hypothesis of marine turtles which excludes Protostegidae from the Cryptodira crown group. Ancestral range estimations derived from our phylogeny imply a European or North American origin of Chelonioidea in the middle-to-late Campanian, approximately 20 Myr earlier than current molecular divergence studies suggest.", "keyphrases": ["turtle", "stratigraphic congruence", "protostegidae", "asmodochelys parhami"]}
{"id": "10.1017/S0022336000026706", "title": "The phylogenetic position of the Tyrannosauridae: implications for theropod systematics", "abstract": "Tyrannosaurids are a well-supported clade of very large predatory dinosaurs of Late Cretaceous Asiamerica. Traditional dinosaurian systematics place these animals within the infraorder Carnosauria with the other large theropods (allosaurids, megalosaurids). A new cladistic analysis indicates that the tyrannosaurs were in fact derived members of the Coelurosauria, a group of otherwise small theropods. Despite certain gross cranial similarities with the large predators of the Jurassic and Early Cretaceous, the Late Cretaceous tyrannosaurids are shown to be the sister group to ornithomimids and troodontids, which share a derived condition of the metatarsus. This clade is found to be nested within Maniraptora, which is a more inclusive taxon than previously recognized. The atrophied carpal structure found in tyrannosaurids and ornithomimids is derived from a maniraptoran condition with a large semilunate carpal, rather than from the plesiomorphic theropod morphology. The taxa \u201cCarnosauria\u201d and \u201cDeinonychosauria\u201d (Dromaeosauridae plus Troodontidae) are shown to be polyphyletic, and the Late Jurassic African form Elaphrosaurus is found to be the sister taxon to Abelisauridae rather than a primitive ornithomimosaur. Purported allosaurid-tyrannosaurid synapomorphies are seen to be largely size-related, present in the larger members of both clades, but absent in smaller members of the Tyrannosauridae. The remaining giant tetanurine theropods (Megalosaurus and Torvosaurus) were found to be progressively distant outgroups to an allosaurid-coelurosaur clade. The inclusion of the Tyrannosauridae within Maniraptora suggests a major adaptive radiation of coelurosaurs within Cretaceous Asiamerica comparable to contemporaneous radiations in various herbivorous dinosaurian clades.", "keyphrases": ["tyrannosauridae", "jurassic", "coelurosaur"]}
{"id": "paleo.009995", "title": "Spontaneous formation and base pairing of plausible prebiotic nucleotides in water", "abstract": "The RNA World hypothesis presupposes that abiotic reactions originally produced nucleotides, the monomers of RNA and universal constituents of metabolism. However, compatible prebiotic reactions for the synthesis of complementary (that is, base pairing) nucleotides and mechanisms for their mutual selection within a complex chemical environment have not been reported. Here we show that two plausible prebiotic heterocycles, melamine and barbituric acid, form glycosidic linkages with ribose and ribose-5-phosphate in water to produce nucleosides and nucleotides in good yields. Even without purification, these nucleotides base pair in aqueous solution to create linear supramolecular assemblies containing thousands of ordered nucleotides. Nucleotide anomerization and supramolecular assemblies favour the biologically relevant \u03b2-anomer form of these ribonucleotides, revealing abiotic mechanisms by which nucleotide structure and configuration could have been originally favoured. These findings indicate that nucleotide formation and selection may have been robust processes on the prebiotic Earth, if other nucleobases preceded those of extant life.", "keyphrases": ["base pairing", "nucleotide", "melamine", "barbituric acid", "aqueous solution"]}
{"id": "10.7717/peerj.7798", "title": "Plant and insect herbivore community variation across the Paleocene\u2013Eocene boundary in the Hanna Basin, southeastern Wyoming", "abstract": "Ecosystem function and stability are highly affected by internal and external stressors. Utilizing paleobotanical data gives insight into the evolutionary processes an ecosystem undergoes across long periods of time, allowing for a more complete understanding of how plant and insect herbivore communities are affected by ecosystem imbalance. To study how plant and insect herbivore communities change during times of disturbance, we quantified community turnover across the Paleocene\u2013Eocene boundary in the Hanna Basin, southeastern Wyoming. This particular location is unlike other nearby Laramide basins because it has an abundance of late Paleocene and Eocene coal and carbonaceous shales and paucity of well-developed paleosols, suggesting perpetually high water availability. We sampled approximately 800 semi-intact dicot leaves from five stratigraphic levels, one of which occurs late in the Paleocene\u2013Eocene thermal maximum (PETM). Field collections were supplemented with specimens at the Denver Museum of Nature & Science. Fossil leaves were classified into morphospecies and herbivore damage was documented for each leaf. We tested for changes in plant and insect herbivore damage diversity using rarefaction and community composition using non-metric multidimensional scaling ordinations. We also documented changes in depositional environment at each stratigraphic level to better contextualize the environment of the basin. Plant diversity was highest during the mid-late Paleocene and decreased into the Eocene, whereas damage diversity was highest at the sites with low plant diversity. Plant communities significantly changed during the late PETM and do not return to pre-PETM composition. Insect herbivore communities also changed during the PETM, but, unlike plant communities, rebound to their pre-PETM structure. These results suggest that insect herbivore communities responded more strongly to plant community composition than to the diversity of species present.", "keyphrases": ["paleocene\u2013eocene boundary", "hanna basin", "southeastern wyoming", "fossil leave"]}
{"id": "10.1002/gj.3287", "title": "The Triassic of Traill \u00d8 and Geographical Society \u00d8, East Greenland: Implications for North Atlantic palaeogeography", "abstract": "The continental Triassic succession north of 72\u00b0 in East Greenland has seen little investigation but is key in understanding how facies belts vary towards the East Greenland Shelf, and more widely in the North Atlantic region, through this period. This study presents sedimentological analysis of exposures in northern Traill \u00d8 (the Mols Bjerge) and further north in northern Geographical Society \u00d8 (Laplace Bjerg). These sections are correlated with the more widely studied succession which lies to the south, in Jameson Land and broad scale palaeogeographical reconstructions of the North Atlantic are presented. A largely continental Triassic succession of 1445 m was recorded from the Mols Bjerge. However, a 125 m thick clean sand unit (the Vega Sund Member), which includes in its upper part the Gr\u00e5klint Beds, is re\u2010interpreted as of shallow marine origin. Over 1200 m of Triassic strata were recognized on Laplace Bjerg. Within this succession 300 m of clean, cross\u2010bedded sandstones are recorded and are correlated with the Vega Sund Member recorded in the Mols Bjerge. The northward increase in thickness of marine strata developed at this time provides evidence for a more extensive marine influence in the north. This work has important implications for regional palaeogeographies and the character of the Triassic succession in adjacent basins, in particular, constraining the southern extent of the Boreal Ocean during the Mid to Late Triassic. Furthermore, the correlations made places bitumen staining, reported from Laplace Bjerg, within Triassic strata, suggesting the viability of a Triassic play at depth in adjacent offshore basins.", "keyphrases": ["east greenland", "north", "late triassic"]}
{"id": "paleo.004010", "title": "A SPALACOLESTINE SPALACOTHERIID (MAMMALIA, TRECHNOTHERIA) FROM THE EARLY CRETACEOUS (BARREMIAN) OF SOUTHERN ENGLAND AND ITS BEARING ON SPALACOTHERIID EVOLUTION", "abstract": "Abstract:\u2002 Bulk screening of Early Cretaceous (Barremian) Wealden Group strata of the Wessex Formation exposed on the south\u2010west and south\u2010east coasts of the Isle of Wight, southern England, has resulted in the recovery of fragmentary remains pertaining to a new spalacolestine spalacotheriid mammal, Yaverlestes gassoni gen. et sp. nov. These represent the first European record of the Spalacolestinae. The remains comprise a dentulous incomplete dentary and isolated upper and lower molariforms, the former representing the most substantial mammal remains yet recovered from the Wealden Group. Hitherto, six species of spalacotheriid mammal were known from the Lower Cretaceous of Europe. All are referred to the genus Spalacotherium but in the case of taxa diagnosed on the basis of isolated lower teeth and other specimens where the post\u2010canine dentition is incompletely known, it is now evident that these referrals should be treated with caution. Furthermore, the new Wessex Formation spalacotheriid and recently described spalacotheriids from the ?Barremian of Japan, and the Barremian and Aptian of China exhibit combinations of characters that suggest that spalacotheriids were more diverse and that their evolution was more complex than previously recognized. The systematic position of an isolated tooth from the basal Cretaceous Lourinh\u00e3 Formation of Portugal is discussed and the tooth reassigned to the Spalacotheriidae. Together with the new Wessex Formation taxon, eight species are now known from the Lower Cretaceous of Europe. The discovery of a spalacolestine in the Barremian Wessex Formation supports the concept of faunal interchange between Europe, Asia and North America during the Early Cretaceous. It also supports derivation of North American spalacotheriids from a European or Eurasian ancestor.", "keyphrases": ["barremian", "southern england", "mammal remain", "spalacotheriidae"]}
{"id": "paleo.006958", "title": "Whence the beardogs? Reappraisal of the Middle to Late Eocene \u2018Miacis\u2019 from Texas, USA, and the origin of Amphicyonidae (Mammalia, Carnivora)", "abstract": "The Middle to Late Eocene sediments of Texas have yielded a wealth of fossil material that offers a rare window on a diverse and highly endemic mammalian fauna from that time in the southern part of North America. These faunal data are particularly significant because the narrative of mammalian evolution in the Paleogene of North America has traditionally been dominated by taxa that are known from higher latitudes, primarily in the Rocky Mountain and northern Great Plains regions. Here we report on the affinities of two peculiar carnivoraforms from the Chambers Tuff of Trans-Pecos, Texas, that were first described 30 years ago as Miacis cognitus and M. australis. Re-examination of previously described specimens and their inclusion in a cladistic analysis revealed the two taxa to be diminutive basal amphicyonids; as such, they are assigned to new genera Gustafsonia and Angelarctocyon, respectively. These two taxa fill in some of the morphological gaps between the earliest-known amphicyonid genus, Daphoenus, and other Middle-Eocene carnivoraforms, and lend additional support for a basal caniform position of the beardogs outside the Canoidea. The amphicyonid lineage had evidently given rise to at least five rather distinct forms by the end of the Middle Eocene. Their precise geographical origin remains uncertain, but it is plausible that southern North America served as an important stage for a very early phase of amphicyonid radiation.", "keyphrases": ["beardog", "middle", "texas", "north america"]}
{"id": "10.1144/0016-76492006-022", "title": "Tectonic models for accretion of the Central Asian Orogenic Belt", "abstract": "The Central Asian Orogenic Belt (c. 1000\u2013250 Ma) formed by accretion of island arcs, ophiolites, oceanic islands, seamounts, accretionary wedges, oceanic plateaux and microcontinents in a manner comparable with that of circum-Pacific Mesozoic\u2013Cenozoic accretionary orogens. Palaeomagnetic and palaeofloral data indicate that early accretion (Vendian\u2013Ordovician) took place when Baltica and Siberia were separated by a wide ocean. Island arcs and Precambrian microcontinents accreted to the active margins of the two continents or amalgamated in an oceanic setting (as in Kazakhstan) by roll-back and collision, forming a huge accretionary collage. The Palaeo-Asian Ocean closed in the Permian with formation of the Solonker suture. We evaluate contrasting tectonic models for the evolution of the orogenic belt. Current information provides little support for the main tenets of the one- or three-arc Kipchak model; current data suggest that an archipelago-type (Indonesian) model is more viable. Some diagnostic features of ridge\u2013trench interaction are present in the Central Asian orogen (e.g. granites, adakites, boninites, near-trench magmatism, Alaskan-type mafic\u2013ultramafic complexes, high-temperature metamorphic belts that prograde rapidly from low-grade belts, rhyolitic ash-fall tuffs). They offer a promising perspective for future investigations.", "keyphrases": ["accretion", "tectonic model", "subduction", "late palaeozoic", "metamorphic rock"]}
{"id": "10.1073/pnas.121176198", "title": "Thirty years on the \u201cBroad Spectrum Revolution\u201d and paleolithic demography", "abstract": "All Paleolithic hominids lived by hunting and collecting wild foods, an aspect of existence that began to disappear only with the emergence of the farming and herding societies of the Neolithic \u226410,000 years ago (10 KYA). What are the roots of this remarkable economic transformation? The answer lies in equally revolutionary changes that took place within certain stone age cultures several millennia before. In 1968, Lewis R. Binford noted what appeared to be substantial diversification of human diets in middle- and high-latitude Europe at the end of the Paleolithic, roughly 12\u20138 KYA (1). Rapid diversification in hunting, food processing, and food storage equipment generally accompanied dietary shifts, symptoms of intensified use of habitats, and fuller exploitation of the potential foodstuffs they contained. Some of this behavior was directed to grinding, drying, and storing nuts, but it also involved small animals (2\u20136). Kent Flannery pushed these observations further in 1969 with his \u201cBroad Spectrum Revolution\u201d (BSR) hypothesis, proposing that the emergence of the Neolithic in western Asia was prefaced by increases in dietary breadth in foraging societies just before this period (7). He argued that subsistence diversification, mainly by adding new species to the diet, raised the carrying capacity of an environment increasingly constrained by climate instability at the end of the Pleistocene.", "keyphrases": ["broad spectrum revolution", "human diet", "environment", "pleistocene"]}
{"id": "10.1017/pab.2015.34", "title": "Effects of the early Toarcian Oceanic Anoxic Event on ichthyosaur body size and faunal composition in the Southwest German Basin", "abstract": "Abstract. \n The Early Jurassic Toarcian Oceanic Anoxic Event is considered one of the most dramatic environmental perturbations of the Mesozoic. An elevated extinction rate among marine invertebrates accompanied rapid environmental changes, but effects on large vertebrates are less understood. We examined changes in ichthyosaur body size in the Posidonia Shale of the Southwest German Basin spanning the extinction interval to assess how environmental changes and biotic crisis among prey species affected large reptiles. We report no species-level extinction among the ichthyosaurs coinciding with peak invertebrate extinction. Large ichthyosaurs were absent from the fauna during the extinction interval, but became more abundant in the immediate aftermath. Stenopterygius quadriscissus, the most abundant species during the extinction interval, increased in body size after the biotic event. Rapid invasion by large taxa occurred immediately following the extinction event at the end of the first ammonite zone of the early Toarcian. Greater mobility permitting exploitation of ephemeral resources and opportunistic feeding behavior may minimize the impacts of environmental change on large vertebrates.", "keyphrases": ["ichthyosaur body size", "southwest german basin", "invertebrate", "vertebrate"]}
{"id": "10.1093/sysbio/syr047", "title": "Divergence time estimation using fossils as terminal taxa and the origins of Lissamphibia.", "abstract": "Were molecular data available for extinct taxa, questions regarding the origins of many groups could be settled in short order. As this is not the case, various strategies have been proposed to combine paleontological and neontological data sets. The use of fossil dates as node age calibrations for divergence time estimation from molecular phylogenies is commonplace. In addition, simulations suggest that the addition of morphological data from extinct taxa may improve phylogenetic estimation when combined with molecular data for extant species, and some studies have merged morphological and molecular data to estimate combined evidence phylogenies containing both extinct and extant taxa. However, few, if any, studies have attempted to estimate divergence times using phylogenies containing both fossil and living taxa sampled for both molecular and morphological data. Here, I infer both the phylogeny and the time of origin for Lissamphibia and a number of stem tetrapods using Bayesian methods based on a data set containing morphological data for extinct taxa, molecular data for extant taxa, and molecular and morphological data for a subset of extant taxa. The results suggest that Lissamphibia is monophyletic, nested within Lepospondyli, and originated in the late Carboniferous at the earliest. This research illustrates potential pitfalls for the use of fossils as post hoc age constraints on internal nodes and highlights the importance of explicit phylogenetic analysis of extinct taxa. These results suggest that the application of fossils as minima or maxima on molecular phylogenies should be supplemented or supplanted by combined evidence analyses whenever possible.", "keyphrases": ["lissamphibia", "calibration", "phylogenetic analysis", "divergence time estimation", "fossil specie"]}
{"id": "10.7717/peerj.9696", "title": "The evolution of feeding within Euchelicerata: data from the fossil groups Eurypterida and Trigonotarbida illustrate possible evolutionary pathways", "abstract": "When the evolution of Euarthropoda is discussed, often the lineage of Chelicerata s. str. is assumed to be the more \u2018primitive\u2019 or \u2018basal\u2019 part of the tree, especially when compared to the other major lineage, Mandibulata. This claimed primitiveness is (at least partly) based on the assumption that different morphological structures are still in an ancestral state and did not evolve any further. One of these sets of structures is the feeding apparatus, which has been stated to be highly advanced in Mandibulata, but not \u2018properly\u2019 developed, or at least not to such a high degree, within Chelicerata s. str. In this study, I reinvestigate the feeding apparatus of different ingroups of Euchelicerata, with a focus on assumed \u2018primitive\u2019 groups such as Eurypterida and Trigonotarbida. The basis of this study is a large amount of material from different museum collections, with fossils with the entire feeding apparatuses being exceptionally well preserved. Based on high-resolution micro-photography and three-dimensional imaging, it is possible to resolve fine details of the feeding apparatuses. The results make clear that the feeding apparatuses of different ingroups of Euchelicerata are highly specialised and often possess morphological structures comparable to those of the feeding apparatuses of representatives of Mandibulata, apparently convergently evolved. Though the reconstruction of the evolution of the feeding apparatus within Euchelicerata is to a certain degree hampered by unclear phylogenetic relationships, there was clearly a shortening of the feeding apparatus from posterior (i.e. only the anterior appendages being involved in the feeding apparatus), probably linked to the colonisation of land in Arachnida. Subjects Evolutionary Studies, Paleontology, Zoology", "keyphrases": ["euchelicerata", "trigonotarbida", "appendage"]}
{"id": "10.5710/amgh.15.02.2018.3181", "title": "Diverse Plant-Insect Associations from the Latest Cretaceous and Early Paleocene of Patagonia, Argentina", "abstract": "Abstract. \n Little is known about the recovery of terrestrial ecosystems after the end-Cretaceous extinction outside of the Western Interior of North America, relatively close to the 66 Ma bolide impact crater in Chicxulub, Mexico. A previous report showed that in Patagonia, Argentina, insect damage on fossil leaves decreased from the latest Cretaceous to early Paleocene but recovered to pre-extinction levels within ca. four million years. Here, we present the first detailed study of these Patagonian plant-insect associations, key components of terrestrial food webs, during the latest Cretaceous and three time slices from the early Paleocene recovery. The lithologic units studied are the uppermost Cretaceous portion of the Lefip\u00e1n Formation and the Danian Salamanca and Pe\u00f1as Coloradas formations in Chubut, Argentina. Seven functional feeding groups are present throughout: hole feeding, margin feeding, skeletonization, surface feeding, piercing and sucking, mining, and galling. Fifty damage types (DTs) were present at Maastrichtian localities, and 39\u201348 were found at Danian localities. Plant-insect associations that apparently went locally extinct at the end of the Cretaceous include several gall, mine, and piercingand-sucking DTs. Based on our preliminary leaf morphotypes, host plants did not provide refuge for specialized insect herbivores across the K/Pg boundary. Despite a decrease in insect damage diversity after the bolide impact, Danian floras hosted a rich array of DTs, including specialized damage such as mines and galls. Many of these early Paleocene DTs were not found in the terminal Cretaceous, providing evidence for a rapid recovery of plant-insect associations regionally.", "keyphrases": ["paleocene", "patagonia", "food webs"]}
{"id": "paleo.001929", "title": "Jaw movement in fossil mammals: analysis, description and visualization", "abstract": "A terminology for and visualizations of different mammalian mastication paths are provided, resulting from orientation of attritional and abrasional facets and striation on fossil (and extant) teeth. The occlusal motion of the left lower jaw is considered, and a moderate wear stage (IDAS 3) is used as standard. In contrast to conventional terminologies, the proposed nomenclature differentiates between the inclination and the direction of the lower jaw movement as projected onto a horizontal plane for each phase of the power stroke. The proposed mastication compass attempts to combine three aspects of the power stroke: (1) the number of phases, (2) the occlusal direction, and (3) the inclination of each phase. Descriptions and visualizations are given for several taxa in order to demonstrate its general applicability. The proposed new terminology and the mastication compass simplify comparisons of different modes of mastication in different mammalian taxa.", "keyphrases": ["visualization", "inclination", "power stroke", "jaw movement", "cycle"]}
{"id": "10.1111/pala.12200", "title": "Graptolite (Hemichordata, Pterobranchia) preservation and identification in the Cambrian Series 3", "abstract": "Due to inadequate preservation, pterobranchs are often difficult to identify in the fossil record, and a better understanding of preservational modes and diagenetic and metamorphic effects is needed for their recognition. Pterobranch hemichordates are common in Cambrian Stage 5 and younger sedimentary rocks, but are frequently overlooked. Often, pterobranch hemichordate colonies have been considered to be algal remains or hydroids. Re\u2010examination of Cambrian Burgess Shale algae reveals that the genera Yuknessia and Dalyia can be recognized as putative early representatives of pterobranch hemichordates. Distinct fusellar construction of the individual zooidal tubes and branching of the creeping proximal part of the colonies are found in the morphologically similar rhabdopleurid pterobranch genus Sphenoecium. The erect tubes of Sphenoecium do not branch and can reach a length of several centimetres. The development of the fusellar construction in this taxon shows a highly irregular development of the suture patterns, but a fairly consistent height of the individual fuselli. The taxon is widely distributed in the Cambrian Series 3, but has regularly been identified as a hydroid or an alga. Sphenoecium wheelerensis from the Cambrian Wheeler Shale of Utah is described as new.", "keyphrases": ["cambrian series", "fusellar construction", "original organic material", "tubaria", "clay template"]}
{"id": "10.1080/03115518.2015.1085749", "title": "New occurrence of Cambroclavus absonus from the lowermost Cambrian of North China and its stratigraphical importance", "abstract": "Li, L.-Y., Zhang, X.-L., Yun, H. & Li, G.-X., October 2015. New occurrence of Cambroclavus absonus from the lowermost Cambrian of North China and its stratigraphical importance. Alcheringa 40, xxx\u2013xxx. ISSN 0311-5518. The problematic Small Shelly Fossil Cambroclavus absonus is described from the Xinji Formation in the Longxian area, which is located near the southwestern margin of the North China Platform. The Xinji Formation, the basal rock unit of the Cambrian in the studied area, yields an assemblage of skeletal fossils that share many common elements with contemporary faunas from South Australia. Sclerites of C. absonus reported herein represent the first occurrence of the species outside Australia, thus extending the palaeogeographic range of the taxon to northern China. To date, palaeogeographic occurrences of Cambroclavus sclerites are restricted to the Peri-Gondwana realm, including South China, Australia, Tarim, Kazakhstan, North China and Western Europe. These occurrences are divided into a Southern Group realm and Northern Group realm. Stratigraphically, Cambroclavus occurs mostly in Cambrian Stage 3 and has three occurrences in Stage 5, separated by Stage 4 in which Cambroclavus has not yet been found. The first appearance datum of Cambroclavus in Cambrian Stage 3 is of importance for regional and inter-regional correlations. In particular, the presence of Cambroclavus absonus in North China allows species-level correlation between North China and South Australia. Luoyang Li [lly@stumail.nwu.edu.cn], Xingliang Zhang [xzhang69@nwu.edu.cn], Hao Yun [yunhao@stumail.nwu.edu.cn], Early Life Institute and State Key Laboratory Of Continental Dynamics, Department of Geology, Northwest University, Xian 710069, PR China; Guoxiang Li [gxli@nigpas.ac.cn], Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing 210008, PR China.", "keyphrases": ["cambroclavus absonus", "stratigraphical importance", "cambrian stage"]}
{"id": "10.1126/science.aas8788", "title": "Rapid Pliocene adaptive radiation of modern kangaroos", "abstract": "Secrets revealed by kangaroo teeth The teeth of mammals display complex adaptations to diet and can thus provide a window into the environments of extinct species. Couzens and Prideaux used such a window to examine the expansion and diversification of kangaroos, Australia's largest herbivores (see the Perspective by Polly). True kangaroos diversified not in response to drying in the Miocene, as suggested by molecular results, but rather as grasslands expanded during the Pliocene. Furthermore, the now-extinct short-faced kangaroos were not declining because of increases in aridity at the end of the Pleistocene but instead were experiencing an increase in dietary divergence. Science, this issue p. 72; see also p. 25 Kangaroos show unexpected patterns of diversification in response to past changes in climate. Differentiating between ancient and younger, more rapidly evolved clades is important for determining paleoenvironmental drivers of diversification. Australia possesses many aridity-adapted lineages, the origins of which have been closely linked to late Miocene continental aridification. Using dental macrowear and molar crown height measurements, spanning the past 25 million years, we show that the most iconic Australian terrestrial mammals, \u201ctrue\u201d kangaroos (Macropodini), adaptively radiated in response to mid-Pliocene grassland expansion rather than Miocene aridity. In contrast, low-crowned, short-faced kangaroos radiated into predominantly browsing niches as the late Cenozoic became more arid, contradicting the view that this was an interval of global browser decline. Our results implicate warm-to-cool climatic oscillations as a trigger for adaptive radiation and refute arguments attributing Pleistocene megafaunal extinction to aridity-forced dietary change.", "keyphrases": ["pliocene", "adaptive radiation", "late miocene"]}
{"id": "paleo.010244", "title": "Periodic Vesicle Formation in Tectonic Fault Zones\u2014an Ideal Scenario for Molecular Evolution", "abstract": "Tectonic fault systems in the continental crust offer huge networks of interconnected channels and cavities. Filled mainly with water and carbon dioxide (CO2), containing a wide variety of hydrothermal chemistry and numerous catalytic surfaces, they may offer ideal reaction conditions for prebiotic chemistry. In these systems, an accumulation zone for organic compounds will develop at a depth of approximately 1 km where CO2 turns sub-critical and dissolved components precipitate. At this point, periodic pressure changes caused for example by tidal influences or geyser activity may generate a cyclic process involving repeated phase transitions of carbon dioxide. In the presence of amphiphilic compounds, this will necessarily lead to the transient formation of coated water droplets in the gas phase and corresponding vesicular structures in the aqueous environment. During this process, the concentration of organic components inside the droplets and vesicles would be drastically increased, allowing for favorable reaction conditions and, in case of the vesicles generated, large trans-membrane concentration gradients. Altogether, the process of periodic formation and destruction of vesicles could offer a perfect environment for molecular evolution in small compartments and for the generation of protocells. The basic process of vesicle formation is reproduced experimentally with a lipid in a water/CO2 system.", "keyphrases": ["vesicle formation", "molecular evolution", "continental crust", "prebiotic chemistry", "protocell"]}
{"id": "10.2478/acpa-2018-0006", "title": "Early Eudicot flower and fruit: Dakotanthus gen. nov. from the Cretaceous Dakota Formation of Kansas and Nebraska, USA", "abstract": "Abstract An extinct plant that populated the eastern margin of the Cretaceous Midcontinental Seaway of North America about 100 million years ago has attracted interest as one of the earliest known bisexual flowers in the fossil record. Reexamination of the type specimen of Carpites cordiformis Lesq., and corresponding specimens from sandstones and clays of the Dakota Formation of Kansas and Nebraska and the correlative Woodbine Sandstone of Texas, with both light microscopy and micro CT scanning, leads to a revised concept of the morphology and affinities of the \u201cRose Creek flower\u201d. The moderately large flowers (22\u201330 mm diameter) have two perianth whorls: five basally fused sepals and five free spatulate petals. The gynoecium is pentacarpellate with five styles. A crescent-shaped nectariferous pad occurs at the base of the gynoecium aligned with each sepal. Ten stamens are inserted at the level of the nectaries, one whorl organized opposite the sepals and another opposite the petals. In situ pollen is oblate, brevitricolporate and finely verrucate. The fruits are loculicidal capsules with persistent calyx and disk. Comparing the full suite of observed characters with those of extant angiosperms indicates particularly close similarity to the monogeneric fabalean family Quillajaceae, with shared features of perianth number and morphology, nectary position and morphology, stamen number and morphology, and gynoecium merosity, although the fossil differs from extant Quillaja in fruit type (capsule vs basally syncarpous follicles) and especially in pollen morphology (10 \u03bcm oblate, microverrucate, vs 30\u201340 \u03bcm prolate, striate).", "keyphrases": ["fruit", "cretaceous dakota formation", "bisexual flower"]}
{"id": "10.1666/13-107", "title": "Developmental paleobiology of the vertebrate skeleton", "abstract": "Abstract Studies of the development of organisms can reveal crucial information on homology of structures. Developmental data are not peculiar to living organisms, and they are routinely preserved in the mineralized tissues that comprise the vertebrate skeleton, allowing us to obtain direct insight into the developmental evolution of this most formative of vertebrate innovations. The pattern of developmental processes is recorded in fossils as successive stages inferred from the gross morphology of multiple specimens and, more reliably and routinely, through the ontogenetic stages of development seen in the skeletal histology of individuals. Traditional techniques are destructive and restricted to a 2-D plane with the third dimension inferred. Effective non-invasive methods of visualizing paleohistology to reconstruct developmental stages of the skeleton are necessary. In a brief survey of paleohistological techniques we discuss the pros and cons of these methods. The use of tomographic methods to reconstruct development of organs is exemplified by the study of the placoderm dentition. Testing evidence for the presence of teeth in placoderms, the first jawed vertebrates, we compare the methods that have been used. These include inferring development from morphology, and using serial sectioning, microCT or synchrotron X-ray tomographic microscopy (SRXTM), to reconstruct growth stages and directions of growth. The ensuing developmental interpretations are biased by the methods and degree of inference. The most direct and reliable method is using SRXTM data to trace sclerochronology. The resulting developmental data can be used to resolve homology and test hypotheses on the origin of evolutionary novelties.", "keyphrases": ["vertebrate skeleton", "tissue", "placoderm"]}
{"id": "10.1017/S1477201903001032", "title": "Osteology and phylogeny of Zalmoxes (n. g.), an unusual Euornithopod dinosaur from the latest Cretaceous of Romania", "abstract": "Synopsis The dinosaurs of the Hateg Basin of Transylvania (late Maastrichtian; western Romania) include Theropoda, Sauropoda, Ornithopoda and Ankylosauria. Of these, one of the most enigmatic taxa is the ornithopod that Franz Baron Nopcsa originally described as Mochlodon suessi and M. robustus in 1902. These two species have come to be regarded as a single species of Rhabdodon, R. robustus, which is distinct from R. priscus from the Late Cretaceous of southern France and northern Spain. This study provides a detailed anatomical revision of the Rhabdodon material that was described originally by Nopcsa during the early decades of the 20th century. It also adds information on material discovered in the Hateg area of Romania since the 1930s. A phylogenetic analysis of basal euornithopods indicates that the non\u2010hadrosaurid material from Hateg comprises two distinct, but congeneric, species. These two species can be distinguished unambiguously from R. priscus. A new genus Zalmoxes is established for the Romanian ornithopod, comprising Z. robustus comb. nov. (the type\u2010species of the genus) and Z. shqiperorum sp. nov. Phylogenetic analysis indicates that the two species of Zalmoxes and R. priscus are united in the monophyletic clade Rhabdodontidae (nov.). Rhabdodontidae constitutes the sibling clade to Iguanodontia. R. septimanicus, M. suessi, and the Villeveyrac Rhabdodon also appear to be members of Rhabdodontidae. The evolutionary implications of this phylogenetic analysis include the recognition of a ghost lineage, extending from the most recent common ancestor of Rhabdodontidae and Iguanodontia, which extends for 73 million years. This extraordinarily long ghost lineage duration may reflect considerable gaps in the history of this group or the geographical isolation of Rhabdodontidae in Europe during much of the Cretaceous period. The area of origin of the Rhabdodontidae + Iguanodontia clade may be North America, while the common ancestor of Rhabdodontidae dispersed to Europe, at that time a marine\u2010dominated region with tectonically\u2010active terrestrial habitats. Adult individuals of Z. robustus are smaller than either of its two closest relatives, Z. shqiperorum and R. priscus, within the Rhabdodontidae, or with many species of Iguanodontia and, therefore, is considered a possible paedomorphic dwarf.", "keyphrases": ["zalmoxes", "romania", "new genus zalmoxes", "rhabdodontidae"]}
{"id": "10.1111/j.1558-5646.1974.tb00757.x", "title": "EVOLUTION OF THE WORLD FAUNA OF AQUATIC FREE\u2010LIVING ARTHROPODS", "abstract": "Is there a grand pattern to the evolution of global biota and ecological systems? This question, which has lately attracted much thought, can rather more easily be approached through considering the relative microcosm of a major taxonomic group evolving within a major adaptive zone. This paper examines the evolution of aquatic free-living arthropods, the occupants of one such adaptive zone, from the Cambrian to the present. Combining established ideas on arthropod evolution with new ideas on measurement, it first develops a quantitative measure of the morphological complexity of arthropod limb mechanisms which in turn provides a rough measure of ecological specialization for the respective animals. This measure is then applied to study of the evolution of the world fauna of aquatic free-living arthropods as reflected in the fossil record. The paper analyzes evolutionary patterns thus revealed, and tests the idea that, within an adaptive zone, the specialization of its occupants increases with their taxonomic diversity. Upshots from the study are surprising estimates for rates of taxonomic diversification and rough quantitative estimates for the percentage completeness of the fossil record through geologic time for taxa of different ranks. Simpson (1969) and May (1973) both wondered whether certain regularities in taxonomic diversity data from the fossil record might not reflect some grand strategy in the evolution of global ecological systems. Paleontologists have begun to further examine such patterns in the evolution of world biota and to interpret them in terms of the evolution of the ecological systems those biota may represent (e.g., Simpson, 1969; Valentine, 1969a,b, 1971, 1973a,b; Valentine and Moores, 1970, 1972; Flessa and Imbrie, 1971, 1973; Raup, 1972). The essence of the approach taken by Valentine and others are the beliefs that a biota is constituted as a hierarchy of taxonomically and ecologically structured systems, that taxonomic structure in some way reflects ecological structure, and that the history of a biota as a system can reliably be interpreted through analysis of data from the fossil record (Valentine, 1968). The kinds and number of kinds of organisms comprising a biota constitute its taxonomic structure. The functional relationships among organisms which, if strong enough, may unite populations, communities, and perhaps an entire biota", "keyphrases": ["world fauna", "arthropod", "complexity"]}
{"id": "paleo.007814", "title": "REDESCRIPTION OF PLATYCRANIELLUS ELEGANS (THERAPSIDA, CYNODONTIA) FROM THE LOWER TRIASSIC OF SOUTH AFRICA, AND THE CLADISTIC RELATIONSHIPS OF EUTHERIODONTS", "abstract": "Abstract:\u2002 Platycraniellus elegans is an enigmatic Triassic cynodont from South Africa that has only been briefly described previously. New preparation of the holotype and additional unpublished material allows a detailed redescription and comparison with different cynodonts. Platycraniellus elegans is recognized as a valid species of basal cynodont. The distinct suborbital angulation of the zygomatic process, previously considered as a diagnostic character in chiniquodontid cynodonts, and more recently observed in some galesaurids, is also present in P.\u2003elegans. A larger, second specimen was initially referred to P.\u2003elegans, but most recently considered to belong to Galesaurus planiceps. Close comparison of this specimen with the holotype of P.\u2003elegans and with galesaurid specimens allows a tentative allocation to G.\u2003planiceps. A cladistic analysis of 32 taxa (two gorgonopsians, seven therocephalians and 23 cynodonts) and 96 craniodental characters places P.\u2003elegans as sister taxon of Eucynodontia. Results from the analysis favour a dichotomy between (1) Cynognathia, including the sectorial\u2010toothed cynodonts Ecteninion, Cynognathus and the gomphodont cynodonts, and (2) Probainognathia, including most sectorial\u2010toothed eucynodonts (e.g. Lumkuia, Probainognathus, Chiniquodon), tritheledontids, tritylodontids and mammaliaforms. The Late Triassic sectorial\u2010toothed Ecteninion is the most basal member of Cynognathia, whereas the Middle Triassic Lumkuia is the basal representative of Probainognathia. Tritylodontids (Oligokyphus and Kayentatherium) are placed among Probainognathia, forming a monophyletic group with the tritheledontid Pachygenelus, whereas Brasilitherium is the sister taxon of Mammaliaformes. The cladistic analysis also indicates paraphyly for Therocephalia, with the whaitsiid Theriognathus identified as sister taxon of Cynodontia.", "keyphrases": ["cynodontia", "triassic", "sister taxon", "mammaliaformes", "redescription"]}
{"id": "10.1111/boj.12119", "title": "Contributions to the diversity in cryptogamic covers in the mid-Palaeozoic: 'Nematothallus' revisited", "abstract": "Compression fossils from the Silurian and Devonian of southern Britain, composed of cuticles and tubes, were described by W. H. Lang as the genus Nematothallus and placed, with Prototaxites, in Nematophytales, related neither to algae nor tracheophytes. Dispersed cuticles of Nematothallus and perforated forms assigned to Cosmochlaina were frequently recovered in macerates, their affinities being unresolved. New collections from a Lochkovian locality in the Welsh Borderland permitted the reconstruction of the stratified thalli of these nematophytes; they comprise a superficial cortex (which produced the cuticles) overlying a palisade zone composed of septate, parallel tubes, presumed to be hyphae, and a basal zone comprising wefts of randomly interwoven hyphae. Excellent three dimensional preservation allows the erection of a new species of Nematothallus, N.\u2009williamii. A similar anatomy is seen in a new group of fossils with either circular incisions in the cortex or complete separation of thickened cortical cells, presumably comprising a developmental sequence. By their stratified organization the nematophytes differ from extant and extinct algae and bryophytes and the enigmatic Spongiophyton. A complex anatomy and septate tubes suggest affinity with lichenized fungi. Limited data support a fungal rather than embryophyte chemistry, but a photobiont is missing. Nematophytes, globally widespread in cryptogamic covers from mid-Ordovician times, added to the biodiversity in early terrestrial ecosystems and enhanced chemical weathering.", "keyphrases": ["cryptogamic cover", "nematothallus", "silurian", "palisade zone", "parallel tube"]}
{"id": "10.1017/S0094837300012185", "title": "Rarefaction analysis of morphological and taxonomic diversity", "abstract": "Our assessment of morphological diversity is influenced by morphological extremes and therefore depends on sample size (taxonomic richness). Rarefaction predicts the morphological diversity that would probably be observed in a sample of reduced size, thereby allowing both compensation for differences in sample size that may be strictly preservational, and analysis of diversity structure, that is, the relationship between morphological and taxonomic diversity. Middle and Late Cambrian trilobites exhibit a diversity structure characterized by many variations on a few morphological themes. In contrast, Middle and Late Ordovician trilobites occupy a larger range of morphospace per unit of species richness. Diversity structure in the Devonian is similar to that in the Middle and Late Ordovician, but the magnitude of morphological diversity is lower in the Devonian, as many fewer species are observed. For blastoids, different aspects of morphological diversity (range of morphospace occupied, number of character states possessed, and number of different regions in morphospace occupied) exhibit different relationships to taxonomic richness. In all cases Permian blastoids are characterized by a diversity structure in which morphological diversity per unit of taxonomic richness is greater than for Devonian blastoids. Changes in morphological diversity in fissiculate blastoids appear to reflect evolution of continuous variation in thecal morphology more than changes in the number of character states. Saunders and Swan's data on Namurian ammonoids illustrate some significant differences in diversity structure among stratigraphic levels, but many apparent differences in morphological diversity are consistent with the possibility that they reflect the sampling of different numbers of species from the same underlying diversity structure. Rarefaction curves are also presented for idealized increases and decreases in diversity, and these are compared to some of the observed changes in trilobites, blastoids, and ammonoids.", "keyphrases": ["taxonomic diversity", "sample size", "morphospace", "sum"]}
{"id": "10.1666/08-111.1", "title": "Shell Orientation Terminology among the Bivalvia (Mollusca): Problems and Proposed Solutions", "abstract": "TRADITIONAL TERMS used to describe shell orientation in bivalves are unsatisfactory in three important ways: 1) for poorly known bivalve taxa, unbiased and directionally neutral terms are sometimes needed to replace anterior and posterior where data are incomplete; 2) there is a striking absence of simple terms to apply to the long and short ends of the shell; and 3) the term lateral is either incorrectly or inconsistently applied. In the following discussion, I shall explore each of these issues and suggest remediation. Although application of terminology describing shell orientation is unlikely to be an issue among extant bivalve taxa, identifying anterior and posterior ends of the shell can sometimes be a speculative business when dealing either with juveniles of living bivalves (Hoggarth, 1987) or, more commonly, with poorly studied or specialized fossil groups, especially where the internal morphology of the shell is either ambiguous, weakly impressed, or limited by preservation. The prevalence of posterior elongation among the Bivalvia has nurtured a disconcerting bias either: 1) to intuitively assume the long end of the shell to be posterior within published descriptions; or 2) to confuse right and left valves in figure captions and typological registers. In passing, it should be noted that the problem of distinguishing \u2018\u2018head-from-tail\u2019\u2019 is not unique to the study of bivalves, but has been a significant issue in other molluscan studies, for example, sorting out the several univalve groups within the polyphyletic \u2018\u2018Class\u2019\u2019 Monoplacophora (see Peel, 1991). Among bivalves, beaks and umbones are rarely central in position; instead, they are placed either in front of or behind the center. Bivalves are thus described as either posteriorly elongate or anteriorly elongate, implying an a priori understanding of the orientation of the soft anatomy within the shell. Whereas the greatest diversity of bivalves favors the posteriorly elongate condition, there are nevertheless significant numbers of bivalve taxa where the condition is reversed, even though the direction of elongation may not be immediately apparent from the shell morphology. For example, among the Palaeotaxodonta, nuculids and solemyids are anteriorly elongate, whereas nuculanids and mallettiids are often posteriorly elongate, yet many shell characters are otherwise broadly shared (Bradshaw and Bradshaw, 1971; Bailey, 1983). Despite their directional ambiguity, the terms equilateral and inequilateral are currently accepted in reference to relative beak placement along the anteroposterior axis. Currently, the shell is called equilateral if the beaks are placed centrally, or inequilateral if beak placement is either in front of or behind the midpoint of the anteroposterior axis, despite the fact that the shell inequality is essentially anteroposterior, not lateral. Conventional usage is problematic on etymological grounds because the original Latin root later-, refers to the sides (sideways or flanks) that is, to the left and right of the plane of commissure, perpendicular to the anteroposterior axis. A similar usage is applied to denticles called lateral teeth, which are not truly \u2018\u2018lateral,\u2019\u2019 but placed either behind or in front of the cardinal teeth. To confuse matters further, the term lateral is simultaneously applied in its proper sense to locations either left or right of the commissure. For example, left and right valves are lateral in placement relative to the commissure. Thus, lateral, when applied to bivalve morphology has a twofold meaning. I therefore recommend that, at least for poorly known bivalves (or perhaps other molluscan groups where applicable), it is desirable in formal descriptions to avoid subjective terms like anterior and posterior where they potentially represent an interpretive bias in favor of directionally neutral terms that are purely descriptive. Obviously, anterior and posterior should (and must) be freely applied once an unequivocal understanding of the anatomy is attained. I further recommend that terms such as equilateral and inequilateral be abandoned with respect to beak placement. Accordingly, I therefore offer the following revisions of orientation terms used in the description of bivalves with reference to shell axes, shell extremities, and shell dorsum and ligamental placement (Fig. 1).", "keyphrases": ["orientation", "bivalvia", "problem", "neutral term"]}
{"id": "10.1017/jpa.2019.30", "title": "Geometric morphometrics to interpret the endophytic egg-laying behavior of Odonata (Insecta) from the Eocene of Patagonia, Argentina", "abstract": "Abstract. Although the order Odonata has a rich fossil record, many questions about its reproductive biology remain unanswered. There are two strategies of egg laying among odonates, exophytic and endophytic, the latter being one of the most revealing vestiges of plant\u2013insect association in the fossil record. We assessed whether geometric morphometrics based on elliptical series of Fourier allow expression of variability of shape in traces of Odonata eggs within a leaf of Eucalyptus chubutensis (Berry) Gonz\u00e1lez (in part), Gonz\u00e1lez, 2009 (Myrtaceae) from Laguna del Hunco (Chubut, Argentina) (early Eocene) and whether this variability is consistent with the ichnotaxonomy of this material. We found that the largest variation corresponds to the compression of the shape while the remaining two components reflect variations in the apex position and its curvature, which changed according to the relative position of the traces in the leaf. There was no evidence that the hardness of the leaf would affect the shape of the egg trace. We postulate that these traces could have been produced by one single female: Variations in the pattern observable in the fossil of an originally three-dimensional structure are consistent with differences in the position of the eggs inserted by a single female who has flexed her abdomen to insert the eggs as she approaches the apex of the leaf (behavior observed also in extant dragonflies). For the first time, endophytic egg traces are analyzed with geometrical morphometrics, and this allows us to make inferences on the oviposition behavior of a female that lived around 52 million years ago.", "keyphrases": ["behavior", "eocene", "trace", "female", "geometric morphometric"]}
{"id": "10.1080/14772019.2022.2082890", "title": "Unravelling the identity of the platanistoid Notocetus vanbenedeni Moreno, 1892 (Cetacea, Odontoceti) from the early Miocene of Patagonia (Argentina)", "abstract": "Platanistoidea remains one of the most evolutionarily intriguing lineages of toothed whales (Odontoceti). The clade comprises mostly extinct species from the late Oligocene\u2013early Miocene onward and a single extant riverine genus (Platanista). There is an ongoing debate as to the membership of Platanistoidea and the causes of their near extinction. In Patagonia (Argentina), the most abundant platanistoid recorded in the lower Miocene Gaiman Formation is Notocetus vanbenedeni, first described by Moreno in 1892 based on two individuals. The goal of the present contribution is to conduct an updated anatomical, palaeobiological and phylogenetic analyses of Notocetus vanbenedeni and hence contribute to an understanding of the evolutionary history of the Platanistoidea. Our analyses, including at least 26 individuals (12 undescribed), show that Notocetus vanbenedeni is a valid platanistoid taxon, recovered as part of a new clade. Among its most outstanding features, this taxon has an elevated dorsal tubercular supraorbital crest formed mainly by the frontal, the precursor of the pneumatized crest of the extant Platanista. Notocetus vanbenedeni also shows initial stages of the plesiomorphic bony connection between the earbones and skull as in Platanista, although the functional implications for hearing remain elusive. The nasal sac system, pterygoid sinus system and morphology of the earbones suggest that this species was able to hear high-frequency sounds and echolocate underwater, similar to extant odontocetes. Thus, Notocetus vanbenedeni presents a mosaic of features that suggest an intermediate platanistoid morphotype. Anatomical differences and phylogenetic analyses suggest that Peruvian specimens could not be referred to this species. The feeding apparatus of Notocetus vanbenedeni makes it the only combination suction-feeder recorded in the early Miocene of Patagonia and among the smallest odontocetes. Finally, the abundant records of Notocetus vanbenedeni in an inner shelf environment with freshwater influence suggest a possible early preference for such protected habitats.", "keyphrases": ["odontoceti", "early miocene", "skull"]}
{"id": "paleo.005525", "title": "Caught in the act? Distraction sinking in ammonoid cephalopods", "abstract": "Two specimens of the Late Mississippian ammonoid cephalopod Metadimorphoceras sp. were recovered from the Bear Gulch Limestone in Montana. This unit was deposited in the lowest part of the Big Snowy Basin, where the bottom waters are thought to have been strongly oxygen deficient. The two nearly equally sized specimens are impressions with soft tissues preserved as brown carbonaceous smears. Diagenetic processes destroyed their aragonitic shells. The preserved soft tissues are interpreted as mandibles, remains of food in the crop, and, possibly, ovaries and eyes. The specimens are on their sides, aperture-to-aperture, and probably the male is on the left and the female is on the right. The specimens are thought to have been in the process of copulation when they died. Copulation by most (all?) externally shelled cephalopods (extinct ammonoids and fossil and extant nautiloids) was probably in a head-to-head, aperture-to-aperture position. This was probably governed in part by restricted accessibility to the female reproductive organs due to the presence of the shell and the ability of both animals to partly withdraw into their shells during copulation. The shell protected them from predators during copulation. In coleoids, which lack an external shell, copulation is a more rapid affair due to the greater vulnerability from predators including other coleoids. We suggest that the fossils from the Bear Gulch Limestone and similar finds of paired ammonoids preserved together with interlocking apertures, and including soft parts in the body chamber, represent examples of ammonoid behavior frozen in time. The two ammonoids were probably too pre-occupied with copulation to notice that they were sinking into the hypoxic bottom waters of the basin and facing suffocation (distraction sinking).", "keyphrases": ["distraction sinking", "cephalopod", "tissue"]}
{"id": "10.1111/j.1096-3642.2010.00683.x", "title": "The origin of modern amphibians: a re-evaluation", "abstract": "There are currently three competing hypotheses seeking to explain the evolutionary origins of modern amphibians. The lepospondyl hypothesis holds that the lysorophian lepospondyls constitute the sister taxon to all lissamphibians. The temnospondyl hypothesis suggests that modern amphibians are most closely related to the dissorophoid temnospondyls. Finally, the polyphyletic hypothesis posits that the modern amphibian orders have separate evolutionary origins from among different groups of Palaeozoic tetrapods. Here, we review the character matrices used in previous studies. These data sets differ significantly in choice of characters. Therefore, we built a matrix based on data from all three hypotheses and analysed key taxa phylogenetically using both Bayesian inference and parsimony. Uncorrected, the supermatrix yielded inconclusive results, demonstrating the presence of at least two phylogenetic optima. When the data were corrected according to new observations on Doleserpeton, Eocaecilia, and other fossil forms, the phylogeny supported the temnospondyl hypothesis of lissamphibian origins. This conclusion is also supported by a careful study of character changes in the individual lineages.", "keyphrases": ["modern amphibian", "temnospondyls", "dissorophoid temnospondyls"]}
{"id": "10.1371/journal.pone.0005746", "title": "Discrepancy between Cranial and DNA Data of Early Americans: Implications for American Peopling", "abstract": "Currently, one of the major debates about the American peopling focuses on the number of populations that originated the biological diversity found in the continent during the Holocene. The studies of craniometric variation in American human remains dating from that period have shown morphological differences between the earliest settlers of the continent and some of the later Amerindian populations. This led some investigators to suggest that these groups\u2014known as Paleomericans and Amerindians respectively\u2014may have arisen from two biologically different populations. On the other hand, most DNA studies performed over extant and ancient populations suggest a single migration of a population from Northeast Asia. Comparing craniometric and mtDNA data of diachronic samples from East Central Argentina dated from 8,000 to 400 years BP, we show here that even when the oldest individuals display traits attributable to Paleoamerican crania, they present the same mtDNA haplogroups as later populations with Amerindian morphology. A possible explanation for these results could be that the craniofacial differentiation was a local phenomenon resulting from random (i.e. genetic drift) and non-random factors (e.g. selection and plasticity). Local processes of morphological differentiation in America are a probable scenario if we take into consideration the rapid peopling and the great ecological diversity of this continent; nevertheless we will discuss alternative explanations as well.", "keyphrases": ["american peopling", "holocene", "craniometric variation"]}
{"id": "10.1073/pnas.1414577112", "title": "Sponge grade body fossil with cellular resolution dating 60 Myr before the Cambrian", "abstract": "Significance Phylogenomic extrapolations indicate the last common ancestor of sponges and eumetazoans existed deep in the Cryogenian, perhaps 200 million years (Myr) before the Cambrian (541 Ma). This inference implies a long Precambrian history of animals phylogenetically allied with sponges. However, there is yet little unequivocal paleontological evidence of Precambrian sponges. Here, we present a newly discovered 600-Myr-old fossil preserved at cellular resolution, displaying multiple poriferan features. The animal was covered with a dense layer of flattened cells resembling sponge pinacocytes, displaying a hollow tubular structure with apparent water inflow and outflow orifices. Although requiring additional specimens of similar form for confirmation, this finding is consistent with phylogenomic inference, and implies the presence of eumetazoan ancestors by 60 Myr before the Cambrian. An extraordinarily well preserved, 600-million-year (Myr)-old, three-dimensionally phosphatized fossil displaying multiple independent characters of modern adult sponges has been analyzed by SEM and synchrotron X-ray tomography. The fossilized animal (Eocyathispongia qiania gen. et sp. nov.) is slightly more than 1.2 mm wide and 1.1 mm tall, is composed of hundreds of thousands of cells, and has a gross structure consisting of three adjacent hollow tubes sharing a common base. The main tube is crowned with a large open funnel, and the others end in osculum-like openings to the exterior. The external surface is densely covered with flat tile-like cells closely resembling sponge pinacocytes, and this layer is punctuated with smaller pores. A dense patch of external structures that display the form of a lawn of sponge papillae has also survived. Within the main funnel, an area where features of the inner surface are preserved displays a regular pattern of uniform pits. Many of them are surrounded individually by distinct collars, mounted in a supporting reticulum. The possibility cannot be excluded that these pits are the remains of a field of choanocytes. The character set evinced by this specimen, ranging from general anatomy to cell type, uniquely indicates that this specimen is a fossil of probable poriferan affinity. So far, we have only this single specimen, and although its organized and complex cellular structure precludes any reasonable interpretation that its origin is abiogenic, confirmation that it is indeed a fossilized sponge will clearly require discovery of additional specimens.", "keyphrases": ["cellular resolution", "myr", "hundred"]}
{"id": "10.1666/06077.1", "title": "How to find a dinosaur, and the role of synonymy in biodiversity studies", "abstract": "Abstract Taxon discovery underlies many studies in evolutionary biology, including biodiversity and conservation biology. Synonymy has been recognized as an issue, and as many as 30\u201360% of named species later turn out to be invalid as a result of synonymy or other errors in taxonomic practice. This error level cannot be ignored, because users of taxon lists do not know whether their data sets are clean or riddled with erroneous taxa. A year-by-year study of a large clade, Dinosauria, comprising over 1000 taxa, reveals how systematists have worked. The group has been subject to heavy review and revision over the decades, and the error rate is about 40% at generic level and 50% at species level. The naming of new species and genera of dinosaurs is proportional to the number of people at work in the field. But the number of valid new dinosaurian taxa depends mainly on the discovery of new territory, particularly new sedimentary basins, as well as the number of paleontologists. Error rates are highest (>50%) for dinosaurs from Europe; less well studied continents show lower totals of taxa, exponential discovery curves, and lower synonymy rates. The most prolific author of new dinosaur names was Othniel Marsh, who named 80 species, closely followed by Friedrich von Huene (71) and Edward Cope (64), but the \u201csuccess rate\u201d (proportion of dinosaurs named that are still regarded as valid) was low (0.14\u20130.29) for these earlier authors, and it appears to improve through time, partly a reflection of reduction in revision time, but mainly because modern workers base their new taxa on more complete specimens. If only 50% of species are valid, evolutionary biologists and conservationists must exercise care in their use of unrevised taxon lists.", "keyphrases": ["synonymy", "discovery curve", "new taxa"]}
{"id": "10.1080/11035897.2011.622049", "title": "A new upper Middle Ordovician\u2013Lower Silurian drillcore standard succession from Borenshult in \u00d6sterg\u00f6tland, southern Sweden: 1. Stratigraphical review with regional comparisons", "abstract": "A recent drilling at Borenshult near Motala resulted in discovery of the stratigraphically most complete succession through the upper Darriwilian\u2013Rhuddanian interval known in \u00d6sterg\u00f6tland. The approximately 70 m long drillcore succession is subdivided into eight formations, the oldest being the late Darriwilian Furudal Limestone and the youngest being the Rhuddanian Motala Formation. Conodonts are used for a detailed biostratigraphic classification of the Borenshult drillcore into three subzones of the Pygodus serra Zone, two subzones of the Pygodus anserinus Zone, and three subzones of the Amorphognathus tvaerensis Zone. The base of the Amorphognathus superbus Zone is taken to be \u223c10 m above the Kinnekulle K-bentonite, that of the Amorphognathus ordovicicus just below the Fj\u00e4cka Shale, and that of the Ozarkodina hassi Zone at the base of the Middle Member of the Loka Formation. Because of its unique lithology and paleontology and its wide geographic occurrence, this member is formally named herein the Skultorp Member. The previously uncertain stratigraphical position of the internationally known \u201cBorenshult fauna\u201d is shown to correlate with the Skultorp Member. A regional comparison of the Borenshult drillcore succession shows it to be most similar to coeval successions in V\u00e4sterg\u00f6tland and Dalarna but there are some significant regional differences. The average rate of net rock accumulation during late Darriwilian and Sandbian time is calculated to be \u223c3\u20134 mm/ka.", "keyphrases": ["succession", "\u00f6sterg\u00f6tland", "kinnekulle k-bentonite"]}
{"id": "10.1073/pnas.1514828112", "title": "Postcranial morphology of the middle Pleistocene humans from Sima de los Huesos, Spain", "abstract": "Significance The middle Pleistocene Sima de los Huesos (SH) fossil collection provides the rare opportunity to thoroughly characterize the postcranial skeleton in a fossil population, comparable only to that obtained in the study of the Neandertal hypodigm and recent (and fossil) modern humans. The SH paleodeme can be characterized as relatively tall, wide, and muscular individuals, who are less encephalized than both Neandertals and modern humans. Some (but not all) Neandertal derived traits are present, which phylogenetically links this population with Neandertals. Thus, the full suite of Neandertal features did not arise all at once, and the evolution of the postcranial skeleton could be characterized as following a mosaic pattern. Current knowledge of the evolution of the postcranial skeleton in the genus Homo is hampered by a geographically and chronologically scattered fossil record. Here we present a complete characterization of the postcranium of the middle Pleistocene paleodeme from the Sima de los Huesos (SH) and its paleobiological implications. The SH hominins show the following: (i) wide bodies, a plesiomorphic character in the genus Homo inherited from their early hominin ancestors; (ii) statures that can be found in modern human middle-latitude populations that first appeared 1.6\u20131.5 Mya; and (iii) large femoral heads in some individuals, a trait that first appeared during the middle Pleistocene in Africa and Europe. The intrapopulational size variation in SH shows that the level of dimorphism was similar to modern humans (MH), but the SH hominins were less encephalized than Neandertals. SH shares many postcranial anatomical features with Neandertals. Although most of these features appear to be either plesiomorphic retentions or are of uncertain phylogenetic polarity, a few represent Neandertal apomorphies. Nevertheless, the full suite of Neandertal-derived features is not yet present in the SH population. The postcranial evidence is consistent with the hypothesis based on the cranial morphology that the SH hominins are a sister group to the later Neandertals. Comparison of the SH postcranial skeleton to other hominins suggests that the evolution of the postcranium occurred in a mosaic mode, both at a general and at a detailed level.", "keyphrases": ["morphology", "los huesos", "hominin"]}
{"id": "paleo.011424", "title": "Rise of the Earliest Tetrapods: An Early Devonian Origin from Marine Environment", "abstract": "Tetrapod fossil tracks are known from the Middle Devonian (Eifelian at ca. 397 million years ago - MYA), and their earliest bony remains from the Upper Devonian (Frasnian at 375\u2013385 MYA). Tetrapods are now generally considered to have colonized land during the Carboniferous (i.e., after 359 MYA), which is considered to be one of the major events in the history of life. Our analysis on tetrapod evolution was performed using molecular data consisting of 13 proteins from 17 species and different paleontological data. The analysis on the molecular data was performed with the program TreeSAAP and the results were analyzed to see if they had implications on the paleontological data collected. The results have shown that tetrapods evolved from marine environments during times of higher oxygen levels. The change in environmental conditions played a major role in their evolution. According to our analysis this evolution occurred at about 397\u2013416 MYA during the Early Devonian unlike previously thought. This idea is supported by various environmental factors such as sea levels and oxygen rate, and biotic factors such as biodiversity of arthropods and coral reefs. The molecular data also strongly supports lungfish as tetrapod's closest living relative.", "keyphrases": ["tetrapod", "early devonian", "marine environment"]}
{"id": "10.1073/pnas.1505596112", "title": "A superarmored lobopodian from the Cambrian of China and early disparity in the evolution of Onychophora", "abstract": "Significance Paleozoic lobopodians constitute a diverse assemblage of worm-like organisms that are known from various exceptional fossil deposits and were among the earliest animals to develop skeletonized body parts for protection. Here, we describe Collinsium ciliosum gen. et sp. nov., an armored lobopodian from the early Cambrian Xiaoshiba Lagerst\u00e4tte (South China). Collinsium belongs to an extinct clade of superarmored lobopodians characterized by supernumerary dorsal spines, and specialized limbs for filter feeding; collectively, these fossil taxa represent a well-defined group within the lineage leading to extant velvet worms (Onychophora). Despite their greater morphological variety and appendage complexity compared with other lobopodians and extant velvet worms, Collinsium and its close relatives embodied a unique, yet ultimately failed, autoecology during the Cambrian explosion. We describe Collinsium ciliosum from the early Cambrian Xiaoshiba Lagerst\u00e4tte in South China, an armored lobopodian with a remarkable degree of limb differentiation including a pair of antenna-like appendages, six pairs of elongate setiferous limbs for suspension feeding, and nine pairs of clawed annulated legs with an anchoring function. Collinsium belongs to a highly derived clade of lobopodians within stem group Onychophora, distinguished by a substantial dorsal armature of supernumerary and biomineralized spines (Family Luolishaniidae). As demonstrated here, luolishaniids display the highest degree of limb specialization among Paleozoic lobopodians, constitute more than one-third of the overall morphological disparity of stem group Onychophora, and are substantially more disparate than crown group representatives. Despite having higher disparity and appendage complexity than other lobopodians and extant velvet worms, the specialized mode of life embodied by luolishaniids became extinct during the Early Paleozoic. Collinsium and other superarmored lobopodians exploited a unique paleoecological niche during the Cambrian explosion.", "keyphrases": ["lobopodian", "onychophora", "xiaoshiba lagerst\u00e4tte", "south china", "tardigrade"]}
{"id": "paleo.009873", "title": "Utility of Marine Benthic Associations as a Multivariate Proxy of Paleobathymetry: A Direct Test from Recent Coastal Ecosystems of North Carolina", "abstract": "Benthic marine fossil associations have been used in paleontological studies as multivariate environmental proxies, with particular focus on their utility as water depth estimators. To test this approach directly, we evaluated modern marine invertebrate communities along an onshore-offshore gradient to determine the relationship between community composition and bathymetry, compare the performance of various ordination techniques, and assess whether restricting community datasets to preservable taxa (a proxy for paleontological data) and finer spatial scales diminishes the applicability of multivariate community data as an environmental proxy. Different indirect (unconstrained) ordination techniques (PCoA, CA, DCA, and NMDS) yielded consistent outcomes: locality Axis 1 scores correlated with actual locality depths, and taxon Axis 1 scores correlated with actual preferred taxon depths, indicating that changes in faunal associations primarily reflect bathymetry, or its environmental correlatives. For datasets restricted to taxa with preservable hard parts, heavily biomineralized mollusks, open ocean habitats, and a single onshore-offshore gradient, the significant correlation between water depth and Axis 1 was still observed. However, for these restricted datasets, the correlation between Axis 1 and bathymetry was reduced and, in most cases, notably weaker than estimates produced by subsampling models. Consistent with multiple paleontological studies, the direct tests carried out here for a modern habitat using known bathymetry suggests that multivariate proxies derived from marine benthic associations may serve as a viable proxy of water depth. The general applicability of multivariate paleocommunity data as an indirect proxy of bathymetry is dependent on habitat type, intrinsic ecological characteristics of dominant faunas, taxonomic scope, and spatial and temporal scales of analysis, highlighting the need for continued testing in present-day depositional settings.", "keyphrases": ["multivariate proxy", "community composition", "bathymetry", "utility"]}
{"id": "10.1029/2007GC001936", "title": "A dynamic explanation for the origin of the western Mediterranean organic\u2010rich layers", "abstract": "The eastern Mediterranean sapropels are among the most intensively investigated phenomena in the paleoceanographic record, but relatively little has been written regarding the origin of the equivalent of the sapropels in the western Mediterranean, the organic\u2010rich layers (ORLs). ORLs are recognized as sediment layers containing enhanced total organic carbon that extend throughout the deep basins of the western Mediterranean and are associated with enhanced total barium concentration and a reduced diversity (dysoxic but not anoxic) benthic foraminiferal assemblage. Consequently, it has been suggested that ORLs represent periods of enhanced productivity coupled with reduced deep ventilation, presumably related to increased continental runoff, in close analogy to the sapropels. We demonstrate that despite their superficial similarity, the timing of the deposition of the most recent ORL in the Alboran Sea is different than that of the approximately coincident sapropel, indicating that there are important differences between their modes of formation. We go on to demonstrate, through physical arguments, that a likely explanation for the origin of the Alboran ORLs lies in the response of the western Mediterranean basin to a strong reduction in surface water density and a shoaling of the interface between intermediate and deep water during the deglacial period. Furthermore, we provide evidence that deep convection had already slowed by the time of Heinrich Event 1 and explore this event as a potential agent for preconditioning deep convection collapse. Important differences between Heinrich\u2010like and deglacial\u2010like influences are highlighted, giving new insights into the response of the western Mediterranean system to external forcing.", "keyphrases": ["western mediterranean", "layer", "recent orl"]}
{"id": "10.5194/cp-11-1181-2015", "title": "Astronomical calibration of the geological timescale: closing the middle Eocene gap", "abstract": "Abstract. To explore cause and consequences of past climate change, very accurate age models such as those provided by the astronomical timescale (ATS) are needed. Beyond 40 million years the accuracy of the ATS critically depends on the correctness of orbital models and radioisotopic dating techniques. Discrepancies in the age dating of sedimentary successions and the lack of suitable records spanning the middle Eocene have prevented development of a continuous astronomically calibrated geological timescale for the entire Cenozoic Era. We now solve this problem by constructing an independent astrochronological stratigraphy based on Earth's stable 405 kyr eccentricity cycle between 41 and 48 million years ago (Ma) with new data from deep-sea sedimentary sequences in the South Atlantic Ocean. This new link completes the Paleogene astronomical timescale and confirms the intercalibration of radioisotopic and astronomical dating methods back through the Paleocene\u2013Eocene Thermal Maximum (PETM, 55.930 Ma) and the Cretaceous\u2013Paleogene boundary (66.022 Ma). Coupling of the Paleogene 405 kyr cyclostratigraphic frameworks across the middle Eocene further paves the way for extending the ATS into the Mesozoic.", "keyphrases": ["geological timescale", "eocene", "ats"]}
{"id": "paleo.012405", "title": "A New Species of Garjainia Ochev, 1958 (Diapsida: Archosauriformes: Erythrosuchidae) from the Early Triassic of South Africa", "abstract": "A new species of the erythrosuchid archosauriform reptile Garjainia Ochev, 1958 is described on the basis of disarticulated but abundant and well-preserved cranial and postcranial material from the late Early Triassic (late Olenekian) Subzone A of the Cynognathus Assemblage Zone of the Burgersdorp Formation (Beaufort Group) of the Karoo Basin of South Africa. The new species, G. madiba, differs from its unique congener, G. prima from the late Olenekian of European Russia, most notably in having large bony bosses on the lateral surfaces of the jugals and postorbitals. The new species also has more teeth and a proportionately longer postacetabular process of the ilium than G. prima. Analysis of G. madiba bone histology reveals thick compact cortices comprised of highly vascularized, rapidly forming fibro-lamellar bone tissue, similar to Erythrosuchus africanus from Subzone B of the Cynognathus Assemblage Zone. The most notable differences between the two taxa are the predominance of a radiating vascular network and presence of annuli in the limb bones of G. madiba. These features indicate rapid growth rates, consistent with data for many other Triassic archosauriforms, but also a high degree of developmental plasticity as growth remained flexible. The diagnoses of Garjainia and of Erythrosuchidae are addressed and revised. Garjainia madiba is the geologically oldest erythrosuchid known from the Southern Hemisphere, and demonstrates that erythrosuchids achieved a cosmopolitan biogeographical distribution by the end of the Early Triassic, within five million years of the end-Permian mass extinction event. It provides new insights into the diversity of the Subzone A vertebrate assemblage, which partially fills a major gap between classic \u2018faunal\u2019 assemblages from the older Lystrosaurus Assemblage Zone (earliest Triassic) and the younger Subzone B of the Cynognathus Assemblage Zone (early Middle Triassic).", "keyphrases": ["erythrosuchidae", "early triassic", "garjainia madiba"]}
{"id": "10.1029/2021PA004241", "title": "Early Paleocene Paleoceanography and Export Productivity in the Chicxulub Crater", "abstract": "The Chicxulub impact caused a crash in productivity in the world's oceans which contributed to the extinction of \u223c75% of marine species. In the immediate aftermath of the extinction, export productivity was locally highly variable, with some sites, including the Chicxulub crater, recording elevated export production. The long\u2010term transition back to more stable export productivity regimes has been poorly documented. Here, we present elemental abundances, foraminifer and calcareous nannoplankton assemblage counts, total organic carbon, and bulk carbonate carbon isotope data from the Chicxulub crater to reconstruct changes in export productivity during the first 3 Myr of the Paleocene. We show that export production was elevated for the first 320 kyr of the Paleocene, declined from 320 kyr to 1.2 Myr, and then remained low thereafter. A key interval in this long decline occurred 900 kyr to 1.2 Myr post impact, as calcareous nannoplankton assemblages began to diversify. This interval is associated with fluctuations in water column stratification and terrigenous flux, but these variables are uncorrelated to export productivity. Instead, we postulate that the turnover in the phytoplankton community from a post\u2010extinction assemblage dominated by picoplankton (which promoted nutrient recycling in the euphotic zone) to a Paleocene pelagic community dominated by relatively larger primary producers like calcareous nannoplankton (which more efficiently removed nutrients from surface waters, leading to oligotrophy) is responsible for the decline in export production in the southern Gulf of Mexico.", "keyphrases": ["paleocene", "export productivity", "chicxulub crater", "nannoplankton"]}
{"id": "10.1080/14772019.2018.1529000", "title": "A new lophocyonid, Izmirictis cani gen. et sp. nov. (Carnivora: Mammalia), from the lower Miocene of Turkey", "abstract": "Lophocyonids are one of the more enigmatic groups of Carnivora in the European Miocene fossil record. Lophocyonids are clearly distinguished from other Feliformia by their peculiar lophodont dental morphology. For this reason, the systematic relationships of the family have been controversial. Here we describe and interpret dental remains from the early Miocene of Sabuncubeli, Turkey, which we attribute to a new genus and species: Izmirictis cani. The phylogenetic analysis allows us to include Izmirictis within a monophyletic group, Lophocyonidae new rank, characterized by the molarization of the anterior premolars (P3 and p4), the lophodont adaptation of the molar dentition and the complex morphology of the incisors. The phylogenetic analysis shows a close relationship between Izmirictis and primitive hyaenids (represented herein by Protictitherium). The divergence between Lophocyonidae and Hyaenidae is estimated by biochronological data to have occurred during the early Miocene (MN2). Dental microwear analysis, although limited by poor dental enamel preservation, indicates that the pronounced lophodonty in Izmirictis cani could be connected to a herbivorous feeding habit. http://zoobank.org/urn:lsid:zoobank.org:pub:8D75382D-6C22-41C1-A47F-BA3EAF766881", "keyphrases": ["izmirictis cani", "carnivora", "miocene", "turkey"]}
{"id": "10.1371/journal.pone.0191400", "title": "A 3D anatomical atlas of appendage musculature in the chelicerate arthropod Limulus polyphemus", "abstract": "Limulus polyphemus, an archetypal chelicerate taxon, has interested both biological and paleontological researchers due to its unique suite of anatomical features and as a useful modern analogue for fossil arthropod groups. To assist the study and documentation of this iconic taxon, we present a 3D atlas on the appendage musculature, with specific focus on the muscles of the cephalothoracic appendages. As L. polyphemus appendage musculature has been the focus of extensive study, depicting the muscles in 3D will facilitate a more complete understanding thereof for future researchers. A large museum specimen was CT scanned to illustrate the major exoskeletal features of L. polyphemus. Micro-CT scans of iodine-stained appendages from fresh, non-museum specimens were digitally dissected to interactively depict appendage sections and muscles. This study has revealed the presence of two new muscles: one within the pushing leg, located dorsally relative to all other patella muscles, and the other within the male pedipalp, located in the modified tibiotarsus. This atlas increases accessibility to important internal and external morphological features of L. polyphemus and reduces the need for destructive fresh tissue dissection of specimens. Scanning, digitally dissecting, and documenting taxa in 3D is a pivotal step towards creating permanent digital records of life on Earth.", "keyphrases": ["atlas", "appendage musculature", "limulus polyphemus", "cephalothoracic appendage"]}
{"id": "10.1144/pygs.52.1.107", "title": "Isotopic variation in fossils and matrix of the Cretaceous Red Chalk at Speeton and South Ferriby, Yorkshire, England", "abstract": "SUMMARY Macro- and micro-fossils (belemnites, planktonic and benthonic foraminifera) and coccolithic matrix from the middle Cretaceous Red Chalk of Yorkshire, UK, have been examined using petrographic, isotopic, and chemical methods to investigate the conditions within which they were formed or altered. Only the belemnites ( Neohibilites sp.) attain the petrographic and geochemical criteria for being well preserved. In contrast, the foraminifera and matrix reveal evidence of diagenetic alteration. Mean belemnite \u03b4 18 O values are \u22120.97\u2030 (PDB) from South Ferriby and \u22121.28\u2030 (PDB) from Speeton. Assuming a sea water SMOW value of \u22121.0\u2030, mean palaeotemperatures calculated from the oxygen isotopic compositions are 15.9\u00b0C and 16.8\u00b0C respectively. The range of isotopic values provided by the belemnites in this study suggests that the isotopic values obtained from early studies of the Chalk, that used only petrographic and/or hand specimen descriptions to screen for diagenetic alteration, could largely represent unaltered values. The palaeotemperatures interpreted from the belemnites are comparable to recent estimates of middle Cretaceous temperature from general circulation model predictions.", "keyphrases": ["cretaceous red chalk", "south ferriby", "palaeotemperature"]}
{"id": "10.1111/let.12025", "title": "Teisseirei barattinia Roselli 1939: the first sphinx moth trace fossil from palaeosols, and its distinct type of wall", "abstract": "The trace fossil Teisseirei barattinia, found in Cenozoic formations of Uruguay and Argentina, is an elongated chamber recognizable by its depressed cross-section, antechamber, and its multi-layered lining with an inner surface texture composed of densely packed sub-rectangular to sub-triangular pits. Our recent behavioural observations on larval and pupal stages of Sphingidae (Lepidoptera), particularly on Manduca rustica, suggest that Teisseirei barattinia is the pupation chamber of a sphinx moth. Last instar larvae of Manduca rustica, Eumorpha anchemolus and E.\u00a0labruscae were placed in terraria to observe their burrowing behaviour and to recover pupation chambers. Chambers show depressed or plane convex cross-sections as T.\u00a0barattinia. The internal surface texture of walls is also similar to that of T.\u00a0barattinia. The same pattern could be obtained experimentally by pressing the true legs of Manduca rustica larva against plasticine. The multi-layered wall structure, shown by T.\u00a0barattinia, is a new type of lining for insect trace fossils in palaeosols that result from soil packing combined with discharges of abundant liquid excretion by soft-bodied larvae, as in the case of Manduca rustica. T.\u00a0barattinia is the first trace fossil documented in palaeosols attributed to sphinx moths and supported by macro and micromorphological comparisons with extant pupation chambers. The shallow emplacement of moth pupation chambers in soils suggests that T.\u00a0barattinia would be a good indicator of palaeosol upper horizons.", "keyphrases": ["trace fossil", "palaeosol", "wall", "sphingidae"]}
{"id": "paleo.010142", "title": "Early Origin for Human-Like Precision Grasping: A Comparative Study of Pollical Distal Phalanges in Fossil Hominins", "abstract": "BACKGROUND\nThe morphology of human pollical distal phalanges (PDP) closely reflects the adaptation of human hands for refined precision grip with pad-to-pad contact. The presence of these precision grip-related traits in the PDP of fossil hominins has been related to human-like hand proportions (i.e. short hands with a long thumb) enabling the thumb and finger pads to contact. Although this has been traditionally linked to the appearance of stone tool-making, the alternative hypothesis of an earlier origin--related to the freeing of the hands thanks to the advent of terrestrial bipedalism--is also possible given the human-like intrinsic hand proportion found in australopiths.\n\n\nMETHODOLOGY/PRINCIPAL FINDINGS\nWe perform morphofunctional and morphometric (bivariate and multivariate) analyses of most available hominin pollical distal phalanges, including Orrorin, Australopithecus, Paranthropous and fossil Homo, in order to investigate their morphological affinities. Our results indicate that the thumb morphology of the early biped Orrorin is more human-like than that of australopiths, in spite of its ancient chronology (ca. 6 Ma). Moreover, Orrorin already displays typical human-like features related to precision grasping.\n\n\nCONCLUSIONS\nThese results reinforce previous hypotheses relating the origin of refined manipulation of natural objects--not stone tool-making--with the relaxation of locomotor selection pressures on the forelimbs. This suggests that human hand length proportions are largely plesiomorphic, in the sense that they more closely resemble the relatively short-handed Miocene apes than the elongated hand pattern of extant hominoids. With the advent of terrestrial bipedalism, these hand proportions may have been co-opted by early hominins for enhanced manipulative capabilities that, in turn, would have been later co-opted for stone tool-making in the genus Homo, more encephalized than the previous australopiths. This hypothesis remains may be further tested by the finding of more complete hands of unequivocally biped early hominins.", "keyphrases": ["precision grasping", "hominin", "advent", "bipedalism", "pollical distal phalanx"]}
{"id": "paleo.006803", "title": "Fossilization transforms vertebrate hard tissue proteins into N-heterocyclic polymers", "abstract": "Vertebrate hard tissues consist of mineral crystallites within a proteinaceous scaffold that normally degrades post-mortem. Here we show, however, that decalcification of Mesozoic hard tissues preserved in oxidative settings releases brownish stained extracellular matrix, cells, blood vessels, and nerve projections. Raman Microspectroscopy shows that these fossil soft tissues are a product of diagenetic transformation to Advanced Glycoxidation and Lipoxidation End Products, a class of N-heterocyclic polymers generated via oxidative crosslinking of proteinaceous scaffolds. Hard tissues in reducing environments, in contrast, lack soft tissue preservation. Comparison of fossil soft tissues with modern and experimentally matured samples reveals how proteinaceous tissues undergo diagenesis and explains biases in their preservation in the rock record. This provides a target, focused on oxidative depositional environments, for finding cellular-to-subcellular soft tissue morphology in fossils and validates its use in phylogenetic and other evolutionary studies.", "keyphrases": ["tissue", "n-heterocyclic polymer", "product", "soft tissue preservation", "diagenesis"]}
{"id": "paleo.003221", "title": "Dermal Armor Histology of Saltasaurus loricatus, an Upper Cretaceous Sauropod Dinosaur from Northwest Argentina", "abstract": "The first unambiguous evidence of the presence of osteoderms in sauropod dinosaurs came from the discovery of Saltasaurus loricatus, a titanosaur from the Upper Cretaceous of Argentina. The dermal armor of Saltasaurus is composed of bony plates and small dermal ossicles. Here, we analyze the bone microstructure of these elements and provide information regarding its origin and development. The bony plates are composed almost entirely of reconstructed cancellous bone. Remains of primary bone consist of coarse bundles of mineralized collagenous fibers towards the external surface. Also, woven fibered bone tissue appears in the basal and lateral regions. Dermal ossicles lack secondary remodeling, and their matrix is formed by three orthogonal systems of collagenous fiber bundles. Growth lines are present in both bony plates and ossicles. Bone histology reveals that osteoderms mainly originated through direct mineralization (metaplasia) of the dermis, although other mechanisms are also involved (at least in the origin of dermal plates). The common features of development and integumental location of the osteoderms of Saltasaurus and other non-related vertebrates (e.g., lepidosaurs, crocodylomorphs) are linked to the intrinsic skeletogenic properties of the dermis.", "keyphrases": ["saltasaurus loricatus", "sauropod dinosaur", "osteoderm", "titanosaur", "secondary remodeling"]}
{"id": "paleo.006269", "title": "The diplacanthid fishes (Acanthodii, Diplacanthiformes, Diplacanthidae) from the Middle Devonian of Scotland", "abstract": "The Diplacanthiformes are a clade of acanthodian fishes which were widespread during the Middle and early Late Devonian. They are best represented in the Middle Devonian, by articulated fossils, fin spines, and abundant scales, the latter particularly from northern Europe. Three species of diplacanthid diplacanthiforms, Diplacanthus crassisimus, Diplacanthus tenuistriatus, and Rhadinacanthus longispinus, are found in Middle Devonian (Eifelian-Givetian) assemblages of articulated fish in northern Scotland. Our detailed study of the dermal structures and endoskeletal shoulder girdles in these fish supports the validity of Rhadinacanthus as a separate genus from Diplacanthus, with the two being differentiated by spine morphology, scale morphology, and histology, and shape and form of the pectoral girdle. In Orkney and Caithness, D. crassisimus first occurs in the Thursius macrolepidotus vertebrate biozone and disappears by the Millerosteus minor + Thursius pholidotus vertebrate biozone. Diplacanthus tenuistriatus and R. longispinus range from the Coccosteus cuspidatus biozone to the end of the Millerosteus minor + Thursius pholidotus biozone. Through comparing the results of our detailed work on the morphology and histology of fin spines and scales from the articulated fish with diplacanthid taxa based on isolated scales and fin spines from the Baltic region, Belarus, and Severnaya Zemlya, we recognize many of the latter taxa from contemporary deposits as junior synonyms of the Scottish species. Phylogenetic analysis of selected gnathostome genera shows the diplacanthiforms Diplacanthus, Rhadinacanthus, Uraniacanthus, and Culmacanthus form a well-supported clade within a larger clade comprising all acanthodian taxa plus a monophyletic Chondrichthyes.", "keyphrases": ["diplacanthiformes", "middle devonian", "phylogenetic analysis", "chondrichthyan"]}
{"id": "paleo.004819", "title": "Life habits and evolutionary biology of new two-winged long-proboscid scorpionflies from mid-Cretaceous Myanmar amber", "abstract": "Long-proboscid scorpionflies are enigmatic, mid-Mesozoic insects associated with gymnosperm pollination. One major lineage, Aneuretopsychina, consists of four families plus two haustellate clades, Diptera and Siphonaptera. One clade, Pseudopolycentropodidae, from mid-Cretaceous Myanmar amber, contains Parapolycentropus. Here, we newly establish Dualula, assigned to Dualulidae, constituting the fifth lineage. Parapolycentropus and Dualula lineages are small, two-winged, with unique siphonate mouthparts for imbibing pollination drops. A cibarial pump provides siphonal food inflow; in Dualula, the siphon base surrounds a hypopharynx housing a small, valved pump constricted to a narrow salivary duct supplying outgoing enzymes for food fluidization. Indirect evidence links long-proboscid mouthpart structure with contemporaneous tubulate ovulate organs. Direct evidence of gymnospermous Cycadopites pollen is associated with one Parapolycentropus specimen. Parapolycentropus and Dualula exhibit hind-wing reduction that would precede haltere formation, likely caused by Ultrabithorax. Distinctive, male Aneuretopsychina genitalia are evident from specimens in copulo, supplemented by mixed-sex individuals of likely male mating swarms.", "keyphrases": ["long-proboscid scorpionflie", "mid-cretaceous myanmar amber", "pseudopolycentropodidae", "dualulidae"]}
{"id": "paleo.002725", "title": "Pre- versus post-mass extinction divergence of Mesozoic marine reptiles dictated by time-scale dependence of evolutionary rates", "abstract": "The fossil record of a major clade often starts after a mass extinction even though evolutionary rates, molecular or morphological, suggest its pre-extinction emergence (e.g. squamates, placentals and teleosts). The discrepancy is larger for older clades, and the presence of a time-scale-dependent methodological bias has been suggested, yet it has been difficult to avoid the bias using Bayesian phylogenetic methods. This paradox raises the question of whether ecological vacancies, such as those after mass extinctions, prompt the radiations. We addressed this problem by using a unique temporal characteristic of the morphological data and a high-resolution stratigraphic record, for the oldest clade of Mesozoic marine reptiles, Ichthyosauromorpha. The evolutionary rate was fastest during the first few million years of ichthyosauromorph evolution and became progressively slower over time, eventually becoming six times slower. Using the later slower rates, estimates of divergence time become excessively older. The fast, initial rate suggests the emergence of ichthyosauromorphs after the end-Permian mass extinction, matching an independent result from high-resolution stratigraphic confidence intervals. These reptiles probably invaded the sea as a new ecosystem was formed after the end-Permian mass extinction. Lack of information on early evolution biased Bayesian clock rates.", "keyphrases": ["mesozoic marine reptile", "evolutionary rate", "emergence", "ichthyosauromorpha", "early triassic"]}
{"id": "10.1073/pnas.1011924108", "title": "Herbivorous ecomorphology and specialization patterns in theropod dinosaur evolution", "abstract": "Interpreting key ecological parameters, such as diet, of extinct organisms without the benefit of direct observation or explicit fossil evidence poses a formidable challenge for paleobiological studies. To date, dietary categorizations of extinct taxa are largely generated by means of modern analogs; however, for many species the method is subject to considerable ambiguity. Here we present a refined approach for assessing trophic habits in fossil taxa and apply the method to coelurosaurian dinosaurs\u2014a clade for which diet is particularly controversial. Our findings detect 21 morphological features that exhibit statistically significant correlations with extrinsic fossil evidence of coelurosaurian herbivory, such as stomach contents and a gastric mill. These traits represent quantitative, extrinsically founded proxies for identifying herbivorous ecomorphology in fossils and are robust despite uncertainty in phylogenetic relationships among major coelurosaurian subclades. The distribution of these features suggests that herbivory was widespread among coelurosaurians, with six major subclades displaying morphological evidence of the diet, and that contrary to previous thought, hypercarnivory was relatively rare and potentially secondarily derived. Given the potential for repeated, independent evolution of herbivory in Coelurosauria, we also test for repetitive patterns in the appearance of herbivorous traits within sublineages using rank concordance analysis. We find evidence for a common succession of increasing specialization to herbivory in the subclades Ornithomimosauria and Oviraptorosauria, perhaps underlain by intrinsic functional and/or developmental constraints, as well as evidence indicating that the early evolution of a beak in coelurosaurians correlates with an herbivorous diet.", "keyphrases": ["ecology", "herbivorous ecomorphology", "cranial diversity", "evolutionary process"]}
{"id": "10.1080/02724634.2017.1347570", "title": "Cranial Anatomy of Morturneria seymourensis from Antarctica, and the Evolution of Filter Feeding in Plesiosaurs of the Austral Late Cretaceous", "abstract": "ABSTRACT \n This paper redescribes the holotype skull of the aristonectine elasmosaur Morturneria seymourensis from the upper Maastrichtian of Seymour Island, Antarctica. This description supports the validity of the genus Morturneria, distinct from the genus Aristonectes from Chile and Argentina. The paroccipital process of Morturneria is plesiomorphic, similar to Alexandronectes and unlike the autapomorphic occiput of Aristonectes. The palate of Morturneria is autapomorphic in possessing a strongly developed midline keel. The cranium of Morturneria is about 60% complete and preserves the anterior skull roof and palate; both regions were previously unknown in any aristonectine. The combination of the Morturneria holotype and recent research on other aristonectines allows the first confident cranial reconstruction of an aristonectine elasmosaur. The cranial anatomy of both Morturneria and its close relatives is derived relative to all other plesiosaurs, possessing a novel suite of dental and oral cavity adaptions. The suspensorium extends far behind the occipital condyle, and the jaw is long and hoop-like; together these features allowed a large gape and oral cavity volume. The palate of Morturneria is strongly keeled, forming arched lateral oral chambers that further increased oral cavity volume. The dentition of Morturneria is similar to that of Aristonectes, and all share autapomorphic interlocking combs of needle-like teeth that occluded outside the mouth and did not meet tip to tip. The upper and lower dentition formed an oral battery that may have functioned like a sieve in straining food particles from substrate ejected from the oral cavity. We theorize that this highly derived suite of adaptations is convergent with extant gray whales and archaic mysticetes and hypothesize that it functioned similarly in sieve feeding following suction. This is the first identification of whale-like filter feeding in any marine reptile, a condition once claimed to be anatomically impossible.", "keyphrases": ["antarctica", "plesiosaur", "oral cavity", "cranial anatomy"]}
{"id": "10.1017/pab.2019.30", "title": "Evaluating Devonian bioregionalization: quantifying biogeographic areas", "abstract": "Abstract. The work of Arthur J. Boucot (vale, 1924\u20132017) is foundational to Devonian biogeography. Cited more than 1000 times and mentioned in excess of 105,000 times, his classification of the Old World, Eastern Americas, and Malvinokaffric realms has become the framework for Devonian biogeographic and faunal studies. This study is the first to test and quantify the biotic area classification using the distributional data of trilobite, brachiopod, and fish taxa across the Lower, Middle, and Late Devonian. The biotic similarity analysis of 676 genera (ca. 30,000 occurrences) of late Silurian (Ludlow\u2013Pridoli) and Devonian taxa represents the largest quantification of distributional data undertaken in Devonian biogeography. The temporal area approach (TAAp), applied here for the first time, failed to recover in the area phenogram many of the realms and regions used by Devonian biogeographers, excepting the Malvinokaffric realm, across the entirety of the Devonian. The Old World and Western Gondwana realms are found to be artificial and in need of revision. Without natural areas, bioregionalizations (area classifications) become unstable and unusable, resulting in authors creating further artificial regions and provinces. This study offers a better solution, namely, to identify artificial areas in existing area classifications using TAAp and biotic similarity analysis and revise them. Area classifications are modeled on taxonomic process (Wilson and Brown 1953; Starrett 1958) and the movement toward revision is necessary to break the cycle of reinvention of realms and regions within bioregionalization.", "keyphrases": ["bioregionalization", "devonian biogeography", "malvinokaffric realm"]}
{"id": "10.4202/app.2009.0084", "title": "Taxonomic Implications of the Residual Colour Patterns of Ampullinid Gastropods and Their Contribution to the Discrimination from Naticids", "abstract": "Caze, B., Merle, D., Le Meur, M., Pacaud, J.-M., Ledon, D., and Saint Martin, J.-P. 2011. Taxonomic implications of the residual colour patterns of ampullinid gastropods and their contribution to the discrimination from naticids. Acta Palaeontologica Polonica 56 (2): 329\u2013347. The diversity of residual colour patterns is revealed for the first time in the European fossil Ampullinidae. The colour patterns were studied under Ultraviolet (UV) light in approximately 3100 specimens belonging to 83 species, 12 genera (Ampullina, Globularia, Crommium, Amaurellina, Pachycrommium, Amauropsina, Ampullonatica, Eocernina, Ampullinopsis, Vanikoropsis, Pictavia, and Ampullospira) and three subgenera (Globularia, Deshayesia, and Cernina within the genus Globularia). Forty-six Cainozoic species revealed residual colour patterns and 29 of them, belonging to six genera (Ampullina, Globularia, Crommium, Amaurellina, Pachycrommium, Amauropsina), are described herein as examples representing the entire diversity of the encountered colour patterns. These patterns are most diverse during the Middle Eocene coincident with the period of highest taxonomic diversity of the Ampullinidae. Four basic classes, regarded as containing possible homologous colour patterns in terms of pigments incorporation modalities, are proposed. Class I, a fluorescent wide diffuse area or spiral stripes, occurs in most of the species, while the three others are more peculiar. Class II, fluorescent axial zigzagging stripes, Class III, fluorescent axial to slightly opisthocline stripes or segments, and Class IV, fluorescent patches forming axial segments by coalescence, allow an easy distinction between the genera Globularia, Pachycrommium, and three peculiar species of Ampullina. The bauplan of the colour patterns revealed in Globularia is very similar to that of the single extant species, Globularia (Cernina) fluctuata. This supports the view of previous authors who classified them in the same genus. Furthermore, at the family level, the peculiar residual patterns belonging to classes II, III, and IV have not been observed in naticid gastropods. Thus our results for the Cainozoic fossil record are consistent with the conclusions based on anatomy and feeding habits, namely that ampullinid gastropods, regarded for a long time as belonging to the family Naticidae, constitute a family apart.", "keyphrases": ["colour pattern", "ampullinid gastropod", "contribution", "naticid"]}
{"id": "10.1093/icb/icz050", "title": "The evolution of a single toe in horses: causes, consequences, and the way forward.", "abstract": "Horses are a classic example of macroevolution in three major traits-large body size, tall-crowned teeth (hypsodonty), and a single toe (monodactyly)-but how and why monodactyly evolved is still poorly understood. Existing hypotheses usually connect digit reduction in horses to the spread and eventual dominance of open-habitat grasslands, which took over from forests during the Cenozoic; digit reduction has been argued to be an adaptation for speed, locomotor economy, stability, and/or increased body size. In this review, we assess the evidence for these (not necessarily mutually exclusive) hypotheses from a variety of related fields, including paleoecology, phylogenetic comparative methods, and biomechanics. Convergent evolution of digit reduction, including in litopterns and artiodactyls, is also considered. We find it unlikely that a single evolutionary driver was responsible for the evolution of monodactyly, because changes in body size, foot posture, habitat, and substrate are frequently found to influence one another (and to connect to broader potential drivers, such as changing climate). We conclude with suggestions for future research to help untangle the complex dynamics of this remarkable morphological change in extinct horses. A path forward should combine regional paleoecology studies, quantitative biomechanical work, and make use of convergence and modern analogs to estimate the relative contributions of potential evolutionary drivers for digit reduction.", "keyphrases": ["single toe", "horse", "macroevolution", "digit reduction"]}
{"id": "paleo.003764", "title": "Mating moths (Tineidae, Ditrysia, Lepidoptera) preserved as frozen behavior inclusion in Baltic Amber (Eocene)", "abstract": "The investigation of amber inclusions provides a unique insight into the biology of animals living millions of years ago, due to their exceptional preservation in nearly lifelike conditions. This is not only true for morphological aspects, aspects of behavior can also be deduced from these fossils. Here, Microlepidoptera are reported from Eocene Baltic amber most likely as a first occurrence of fossil Lepidoptera found in copula. The moths belong to Tineidae (tineid moths includes clothes moths) and are described as a new species and new genus, Forcepsites michalskii. The clasping organ of the male is quite uncommon for moths from Baltic amber, with a ventral and dorsal part, each ending in two parallel, thorn-like protuberances, and seemingly not being formed by the valvae. The co-occurrence of male and female, most likely in copula, allowed studying their sexual dimorphism directly, and there is evidence that the habitat of this species is the site of resin production in the Baltic amber forest. From sexual dimorphism of the antennae and eye morphology it is interpreted that the female was the calling sex for mating in this species. Thilo C. Fischer. F\u00f6rderverein der Bayerischen Staatssammlung f\u00fcr Pal\u00e4ontologie und Historische Geologie M\u00fcnchen Richard-Wagner-Stra\u00dfe 10, D-80333 M\u00fcnchen, Germany. thilo.fischer@tum.de Marie K. H\u00f6rnig. University of Greifswald, Zoological Institute and Museum, Cytology and Evolutionary Biology, Soldmannstr. 23, D-17489 Greifswald, Germany. marie.hoernig@palaeo-evo-devo.info", "keyphrases": ["moth", "tineidae", "behavior", "baltic amber"]}
{"id": "10.1098/rsbl.2019.0284", "title": "Palaeo-trajectories of forest savannization in the southern Congo", "abstract": "Tropical savannah and forest are thought to represent alternative stable states in ecosystem structure in some climates. The implication is that biomes are maintained by positive feedbacks, e.g. with fire, and that historical distributions could play a role in determining modern ones. In this context, climate alone does not govern transitions between biomes, and understanding the causes and pathways of such transitions becomes crucial. Here, we use a multi-proxy analysis of a 2000-year core to evaluate modes of transition in vegetation structure and fire regimes. We demonstrate a first transition ca 1540 BP, when a cyclic fire regime entered a forested landscape, eventually resulting, by ca 1060 BP, in a transition to a more open savannah-like or mosaicked structure. This pattern may parallel currently accelerating fire regimes in tropical forests suggesting that fires can savannize forests, but perhaps more slowly than feared. Finally, ca 540 BP, a drought combined with anthropogenic influences resulted in a conclusive transition to savannah, probably resembling the modern landscape in the region. We show here that fire interacted with drought to transition forest to savannah, suggesting that disturbance by fire can be a major driver of biome change.", "keyphrases": ["forest", "southern congo", "savannah"]}
{"id": "10.1073/pnas.95.12.6893", "title": "A genetic record of population isolation in pocket gophers during Holocene climatic change.", "abstract": "A long-standing question in Quaternary paleontology is whether climate-induced, population-level phenotypic change is a result of large-scale migration or evolution in isolation. To directly measure genetic variation through time, ancient DNA and morphologic variation was measured over 2,400 years in a Holocene sequence of pocket gophers (Thomomys talpoides) from Lamar Cave, Yellowstone National Park, Wyoming. Ancient specimens and modern samples collected near Lamar Cave share mitochondrial cytochrome b sequences that are absent from adjacent localities, suggesting that the population was isolated for the entire period. In contrast, diastemal length, a morphologic character correlated with body size and nutritional level, changed predictably in response to climatic change. Our results demonstrate that small mammal populations can experience the long-term isolation assumed by many theoretical models of microevolutionary change.", "keyphrases": ["pocket gopher", "climatic change", "lamar cave"]}
{"id": "paleo.011835", "title": "Insights into the timing, intensity and natural setting of Neanderthal occupation from the geoarchaeological study of combustion structures: A micromorphological and biomarker investigation of El Salt, unit Xb, Alcoy, Spain", "abstract": "Middle Paleolithic lithic and faunal assemblages throughout Eurasia reflect short-term Neanderthal occupations, which suggest high group mobility. However, the timing of these short-term occupations, a key factor to assess group mobility and territorial range, remains unresolved. Anthropogenic combustion structures are prominent in the Middle Paleolithic record and conceal information on the timing and intensity and natural setting of their associated human occupations. This paper examines a concentration of eleven combustion structures from unit Xb of El Salt, a Middle Paleolithic site in Spain through a geoarchaeological approach, in search of temporal, human impact and paleoenvironmental indicators to assess the timing, intensity and natural setting of the associated human occupations. The study was conducted using micromorphology, lipid biomarker analysis and compound specific isotope analysis. Results show in situ hearths built on different diachronic topsoils rich in herbivore excrements and angiosperm plant residues with rare anthropogenic remains. These data are suggestive of low impact, short-term human occupations separated by relatively long periods of time, with possible indicators of seasonality. Results also show an absence of conifer biomarkers in the mentioned topsoils and presence of conifer charcoal among the fuel residues (ash), indicating that fire wood was brought to the site from elsewhere. A microscopic and molecular approach in the study of combustion structures allows us to narrow down the timescale of archaeological analysis and contributes valuable information towards an understanding of Neanderthal group mobility and settlement patterns.", "keyphrases": ["neanderthal occupation", "combustion structure", "spain", "high group mobility", "long period"]}
{"id": "10.1093/sysbio/syq054", "title": "Dating primate divergences through an integrated analysis of palaeontological and molecular data.", "abstract": "Estimation of divergence times is usually done using either the fossil record or sequence data from modern species. We provide an integrated analysis of palaeontological and molecular data to give estimates of primate divergence times that utilize both sources of information. The number of preserved primate species discovered in the fossil record, along with their geological age distribution, is combined with the number of extant primate species to provide initial estimates of the primate and anthropoid divergence times. This is done by using a stochastic forwards-modeling approach where speciation and fossil preservation and discovery are simulated forward in time. We use the posterior distribution from the fossil analysis as a prior distribution on node ages in a molecular analysis. Sequence data from two genomic regions (CFTR on human chromosome 7 and the CYP7A1 region on chromosome 8) from 15 primate species are used with the birth-death model implemented in mcmctree in PAML to infer the posterior distribution of the ages of 14 nodes in the primate tree. We find that these age estimates are older than previously reported dates for all but one of these nodes. To perform the inference, a new approximate Bayesian computation (ABC) algorithm is introduced, where the structure of the model can be exploited in an ABC-within-Gibbs algorithm to provide a more efficient analysis.", "keyphrases": ["molecular data", "fossil preservation", "posterior distribution", "molecular clock analysis"]}
{"id": "paleo.008306", "title": "Amphilagus plicadentis (Lagomorpha, Mammalia) from the Tagay locality (Olkhon Island, Baikal region, Eastern Siberia)", "abstract": "New excavations in the Tagay locality have revealed the presence of Amphilagus plicadentis Erbajeva, 2013, which belongs to the palaeolagine Lagomorpha rather than leporids, previously referred to Procaprolagus sp. (Logachev et al., 1964) . Herein, we report a comprehensive morphological description of this species and compare it with the other known species of the genus Amphilagus. The Tagay lagomorph is conspecific with the Early Miocene species Amphilagus plicadentis found at locality Unkheltseg (UNCH-A) (biozone D; Early Miocene) in the Valley of Lakes, Central Mongolia. The Tagay specimens suggest a more advanced evolutionary stage of A. plicadentis and an age around Early/Middle Miocene transition.", "keyphrases": ["lagomorpha", "palaeolagidae", "small mammal tooth", "fossil collection", "turtle"]}
{"id": "10.1590/S0074-02762003000900016", "title": "Human intestinal parasites in the past: new findings and a review.", "abstract": "Almost all known human specific parasites have been found in ancient feces. A review of the paleoparasitological helminth and intestinal protozoa findings available in the literature is presented. We also report the new paleoparasitologic findings from the examination performed in samples collected in New and Old World archaeological sites. New finds of ancylostomid, Ascaris lumbricoides, Trichuris trichiura, Enterobius vermicularis, Trichostrongylus spp., Diphyllobothrium latum, Hymenolepis nana and Acantocephalan eggs are reported. According to the findings, it is probable that A. lumbricoides was originally a human parasite. Human ancylostomids, A. lumbricoides and T. trichiura, found in the New World in pre-Columbian times, have not been introduced into the Americas by land via Beringia. These parasites could not supported the cold climate of the region. Nomadic prehistoric humans that have crossed the Bering Land Bridge from Asia to the Americas in the last glaciation, probably during generations, would have lost these parasites, which life cycles need warm temperatures in the soil to be transmitted from host to host. Alternative routes are discussed for human parasite introduction into the Americas.", "keyphrases": ["parasite", "review", "old world", "asia"]}
{"id": "paleo.007627", "title": "\u2018Nedoceratops\u2019: An Example of a Transitional Morphology", "abstract": "Background The holotype and only specimen of the chasmosaurine ceratopsid dinosaur \u2018Nedoceratops hatcheri\u2019 has been the source of considerable taxonomic debate since its initial description. At times it has been referred to its own genus while at others it has been considered synonymous with the contemporaneous chasmosaurine Triceratops. Most recently, the debate has focused on whether the specimen represents an intermediate ontogenetic stage between typical young adult Triceratops and the proposed mature morphology, which was previously considered to represent a distinct genus, \u2018Torosaurus\u2019. Methodology/Principal Findings The only specimen of \u2018Nedoceratops hatcheri\u2019 was examined and the proposed diagnostic features of this taxon were compared with other chasmosaurine ceratopsids. Every suggested autapomorphy of \u2018Nedoceratops\u2019 is found in specimens of Triceratops. In this study, Triceratops includes the adult \u2018Torosaurus\u2019 morphology. The small parietal fenestra and elongate squamosals of Nedoceratops are consistent with a transition from a short, solid parietal-squamosal frill to an expanded, fenestrated condition. Objections to this hypothesis regarding the number of epiossifications of the frill and alternations of bone surface texture were explored through a combination of comparative osteology and osteohistology. The synonymy of the three taxa was further supported by these investigations. Conclusions/Significance The Triceratops, \u2018Torosaurus\u2019, and \u2018Nedoceratops\u2019 morphologies represent ontogenetic variation within a single genus of chasmosaurine: Triceratops. This study highlights how interpretations of dinosaur paleobiology, biodiversity, and systematics may be affected by ascribing ontogenetic and other intraspecific variation a taxonomic significance.", "keyphrases": ["nedoceratop", "nedoceratops hatcheri", "ontogenetic stage", "torosaurus", "single genus"]}
{"id": "10.1126/science.1135274", "title": "Paleocene-Eocene Thermal Maximum and the Opening of the Northeast Atlantic", "abstract": "The Paleocene-Eocene thermal maximum (PETM) has been attributed to a sudden release of carbon dioxide and/or methane. 40Ar/39Ar age determinations show that the Danish Ash-17 deposit, which overlies the PETM by about 450,000 years in the Atlantic, and the Skraenterne Formation Tuff, representing the end of 1 \u00b1 0.5 million years of massive volcanism in East Greenland, are coeval. The relative age of Danish Ash-17 thus places the PETM onset after the beginning of massive flood basalt volcanism at 56.1 \u00b1 0.4 million years ago but within error of the estimated continental breakup time of 55.5 \u00b1 0.3 million years ago, marked by the eruption of mid-ocean ridge basalt\u2013like flows. These correlations support the view that the PETM was triggered by greenhouse gas release during magma interaction with basin-filling carbon-rich sedimentary rocks proximal to the embryonic plate boundary between Greenland and Europe.", "keyphrases": ["northeast atlantic", "eruption", "paleocene-eocene thermal maximum", "ash layer", "radiometric dating"]}
{"id": "10.1111/j.1469-185X.2010.00139.x", "title": "Testing the effect of the rock record on diversity: a multidisciplinary approach to elucidating the generic richness of sauropodomorph dinosaurs through time", "abstract": "The accurate reconstruction of palaeobiodiversity patterns is central to a detailed understanding of the macroevolutionary history of a group of organisms. However, there is increasing evidence that diversity patterns observed directly from the fossil record are strongly influenced by fluctuations in the quality of our sampling of the rock record; thus, any patterns we see may reflect sampling biases, rather than genuine biological signals. Previous dinosaur diversity studies have suggested that fluctuations in sauropodomorph palaeobiodiversity reflect genuine biological signals, in comparison to theropods and ornithischians whose diversity seems to be largely controlled by the rock record. Most previous diversity analyses that have attempted to take into account the effects of sampling biases have used only a single method or proxy: here we use a number of techniques in order to elucidate diversity. A global database of all known sauropodomorph body fossil occurrences (2024) was constructed. A taxic diversity curve for all valid sauropodomorph genera was extracted from this database and compared statistically with several sampling proxies (rock outcrop area and dinosaur\u2010bearing formations and collections), each of which captures a different aspect of fossil record sampling. Phylogenetic diversity estimates, residuals and sample\u2010based rarefaction (including the first attempt to capture \u2018cryptic\u2019 diversity in dinosaurs) were implemented to investigate further the effects of sampling. After \u2018removal\u2019 of biases, sauropodomorph diversity appears to be genuinely high in the Norian, Pliensbachian\u2013Toarcian, Bathonian\u2013Callovian and Kimmeridgian\u2013Tithonian (with a small peak in the Aptian), whereas low diversity levels are recorded for the Oxfordian and Berriasian\u2013Barremian, with the Jurassic/Cretaceous boundary seemingly representing a real diversity trough. Observed diversity in the remaining Triassic\u2013Jurassic stages appears to be largely driven by sampling effort. Late Cretaceous diversity is difficult to elucidate and it is possible that this interval remains relatively under\u2010sampled. Despite its distortion by sampling biases, much of sauropodomorph palaeobiodiversity can be interpreted as a reflection of genuine biological signals, and fluctuations in sea level may account for some of these diversity patterns.", "keyphrases": ["rock record", "richness", "sampling", "ornithischian", "neosauropod"]}
{"id": "10.1017/pab.2016.20", "title": "Ediacaran distributions in space and time: testing assemblage concepts of earliest macroscopic body fossils", "abstract": "Abstract. The mid-late Ediacaran Period (\u223c579\u2013541 Ma) is characterized by globally distributed marine soft-bodied organisms of unclear phylogenetic affinities colloquially called the \u201cEdiacara biota.\u201d Despite an absence of systematic agreement, previous workers have tested for underlying factors that may control the occurrence of Ediacaran macrofossils in space and time. Three taxonomically distinct \u201cassemblages,\u201d termed the Avalon, White Sea, and Nama, were identified and informally incorporated into Ediacaran biostratigraphy. After \u223c15 years of new fossil discoveries and taxonomic revision, we retest the validity of these assemblages using a comprehensive database of Ediacaran macrofossil occurrences. Using multivariate analysis, we also test the degree to which taphonomy, time, and paleoenvironment explain the taxonomic composition of these assemblages. We find that: (1) the three assemblages remain distinct taxonomic groupings; (2) there is little support for a large-scale litho-taphonomic bias present in the Ediacaran; and (3) there is significant chronostratigraphic overlap between the taxonomically and geographically distinct Avalonian and White Sea assemblages ca. 560\u2013557 Ma. Furthermore, both assemblages show narrow bathymetric ranges, reinforcing that they were paleoenvironmental\u2014ecological biotopes and spatially restricted in marine settings. Meanwhile, the Nama assemblage appears to be a unique faunal stage, defined by a global loss of diversity, coincident with a noted expansion of bathymetrically unrestricted, long-ranging Ediacara taxa. These data reinforce that Ediacaran biodiversity and stratigraphic ranges of its representative taxa must first statistically account for varying likelihood of preservation at a local scale to ultimately aggregate the Ediacaran macrofossil record into a global biostratigraphic context.", "keyphrases": ["space", "white sea", "nama assemblage"]}
{"id": "paleo.011322", "title": "Required Levels of Catalysis for Emergence of Autocatalytic Sets in Models of Chemical Reaction Systems", "abstract": "The formation of a self-sustaining autocatalytic chemical network is a necessary but not sufficient condition for the origin of life. The question of whether such a network could form \u201cby chance\u201d within a sufficiently complex suite of molecules and reactions is one that we have investigated for a simple chemical reaction model based on polymer ligation and cleavage. In this paper, we extend this work in several further directions. In particular, we investigate in more detail the levels of catalysis required for a self-sustaining autocatalytic network to form. We study the size of chemical networks within which we might expect to find such an autocatalytic subset, and we extend the theoretical and computational analyses to models in which catalysis requires template matching.", "keyphrases": ["catalysis", "autocatalytic chemical network", "sufficient condition"]}
{"id": "paleo.009284", "title": "Fossil biogeography: a new model to infer dispersal, extinction and sampling from palaeontological data", "abstract": "Methods in historical biogeography have revolutionized our ability to infer the evolution of ancestral geographical ranges from phylogenies of extant taxa, the rates of dispersals, and biotic connectivity among areas. However, extant taxa are likely to provide limited and potentially biased information about past biogeographic processes, due to extinction, asymmetrical dispersals and variable connectivity among areas. Fossil data hold considerable information about past distribution of lineages, but suffer from largely incomplete sampling. Here we present a new dispersal\u2013extinction\u2013sampling (DES) model, which estimates biogeographic parameters using fossil occurrences instead of phylogenetic trees. The model estimates dispersal and extinction rates while explicitly accounting for the incompleteness of the fossil record. Rates can vary between areas and through time, thus providing the opportunity to assess complex scenarios of biogeographic evolution. We implement the DES model in a Bayesian framework and demonstrate through simulations that it can accurately infer all the relevant parameters. We demonstrate the use of our model by analysing the Cenozoic fossil record of land plants and inferring dispersal and extinction rates across Eurasia and North America. Our results show that biogeographic range evolution is not a time-homogeneous process, as assumed in most phylogenetic analyses, but varies through time and between areas. In our empirical assessment, this is shown by the striking predominance of plant dispersals from Eurasia into North America during the Eocene climatic cooling, followed by a shift in the opposite direction, and finally, a balance in biotic interchange since the middle Miocene. We conclude by discussing the potential of fossil-based analyses to test biogeographic hypotheses and improve phylogenetic methods in historical biogeography.", "keyphrases": ["dispersal", "des", "fossil occurrence", "phylogenetic tree", "extinction rate"]}
{"id": "paleo.010269", "title": "Eggshell geochemistry reveals ancestral metabolic thermoregulation in Dinosauria", "abstract": "All major groups of Mesozoic dinosaurs exhibited metabolically mediated thermoregulation based on clumped isotopes in eggshells. Studying the origin of avian thermoregulation is complicated by a lack of reliable methods for measuring body temperatures in extinct dinosaurs. Evidence from bone histology and stable isotopes often relies on uncertain assumptions about the relationship between growth rate and body temperature, or the isotopic composition (\u03b418O) of body water. Clumped isotope (\u039447) paleothermometry, based on binding of 13C to 18O, provides a more robust tool, but has yet to be applied across a broad phylogenetic range of dinosaurs while accounting for paleoenvironmental conditions. Applying this method to well-preserved fossil eggshells demonstrates that the three major clades of dinosaurs, Ornithischia, Sauropodomorpha, and Theropoda, were characterized by warm body temperatures. Dwarf titanosaurs may have exhibited similar body temperatures to larger sauropods, although this conclusion is provisional, given current uncertainties in taxonomic assignment of dwarf titanosaur eggshell. Our results nevertheless reveal that metabolically controlled thermoregulation was the ancestral condition for Dinosauria.", "keyphrases": ["dinosauria", "body temperature", "eggshell"]}
{"id": "10.1002/ajpa.21296", "title": "The usefulness of caries frequency, depth, and location in determining cariogenicity and past subsistence: a test on early and later agriculturalists from the Peruvian coast.", "abstract": "Dental markers have been used to unravel particularities of paleodiet, subsistence, social structure, and health. This article aims to compare oral pathology among four pre-Columbian groups with different degrees of agricultural and socio-cultural development but comparable ecological conditions who lived on the coastal desert of Peru. Three of these groups are assigned to distinct phases of the Formative Period (2500-1 BC), a time critical for our understanding of the development of agriculture and social complexity. The fourth group corresponds to the Late Intermediate Period (1000-1470 AD), when agriculture had its apogee and society was highly stratified. In this study we test whether there is an increase (1) in the frequency of carious lesions and (2) in caries depth, and (3) if there is a shift from occlusal to extra-occlusal caries locations with the development of agriculture. Therefore, we analyze the frequencies of carious lesions and antemortem tooth loss (AMTL), the caries distributions by age, sex, and type of tooth, as well as the tissues affected by, and the location of the carious lesions. Since there are no significant differences in the frequencies of carious lesions and AMTL between the groups, we reject hypothesis 1. In contrast, caries depth does increase, and caries location changes from occlusal to extra-occlusal sites with agricultural development. However, we can only corroborate hypothesis 2 and 3 when taking into consideration dental wear. Thus, we recommend that caries depth and locations should be used with evaluations of dental wear to reconstruct subsistence in ancient populations.", "keyphrases": ["location", "subsistence", "carious lesion", "tissue"]}
{"id": "10.1098/rspb.2001.1921", "title": "An analysis of dinosaurian biogeography: evidence for the existence of vicariance and dispersal patterns caused by geological events", "abstract": "As the supercontinent Pangaea fragmented during the Mesozoic era, dinosaur faunas were divided into isolated populations living on separate continents. It has been predicted, therefore, that dinosaur distributions should display a branching (\u2018vicariance\u2019) pattern that corresponds with the sequence and timing of continental break\u2010up. Several recent studies, however, minimize the importance of plate tectonics and instead suggest that dispersal and regional extinction were the main controls on dinosaur biogeography. Here, in order to test the vicariance hypothesis, we apply a cladistic biogeographical method to a large dataset on dinosaur relationships and distributions. We also introduce a methodological refinement termed \u2018time\u2010slicing\u2019, which is shown to be a key step in the detection of ancient biogeographical patterns. These analyses reveal biogeographical patterns that closely correlate with palaeogeography. The results provide the first statistically robust evidence that, from Middle Jurassic to mid\u2010Cretaceous times, tectonic events had a major role in determining where and when particular dinosaur groups flourished. The fact that evolutionary trees for extinct organisms preserve such distribution patterns opens up a new and fruitful direction for palaeobiogeographical research.", "keyphrases": ["vicariance", "dinosaur faunas", "influence"]}
{"id": "paleo.007555", "title": "Evolutionary biomechanics: hard tissues and soft evidence?", "abstract": "Biomechanical modelling is a powerful tool for quantifying the evolution of functional performance in extinct animals to understand key anatomical innovations and selective pressures driving major evolutionary radiations. However, the fossil record is composed predominantly of hard parts, forcing palaeontologists to reconstruct soft tissue properties in such models. Rarely are these reconstruction approaches validated on extant animals, despite soft tissue properties being highly determinant of functional performance. The extent to which soft tissue reconstructions and biomechanical models accurately predict quantitative or even qualitative patterns in macroevolutionary studies is therefore unknown. Here, we modelled the masticatory system in extant rodents to objectively test the ability of current muscle reconstruction methods to correctly identify quantitative and qualitative differences between macroevolutionary morphotypes. Baseline models generated using measured soft tissue properties yielded differences in muscle proportions, bite force, and bone stress expected between extant sciuromorph, myomorph, and hystricomorph rodents. However, predictions from models generated using reconstruction methods typically used in fossil studies varied widely from high levels of quantitative accuracy to a failure to correctly capture even relative differences between macroevolutionary morphotypes. Our novel experiment emphasizes that correctly reconstructing even qualitative differences between taxa in a macroevolutionary radiation is challenging using current methods. Future studies of fossil taxa should incorporate systematic assessments of reconstruction error into their hypothesis testing and, moreover, seek to expand primary datasets on muscle properties in extant taxa to better inform soft tissue reconstructions in macroevolutionary studies.", "keyphrases": ["modelling", "tissue reconstruction", "muscle", "macroevolutionary morphotype"]}
{"id": "paleo.011206", "title": "Deep drilling reveals massive shifts in evolutionary dynamics after formation of ancient ecosystem", "abstract": "A volatile assemblage of short-lived endemic species developed into a stable community of long-lived species in Lake Ohrid. The scarcity of high-resolution empirical data directly tracking diversity over time limits our understanding of speciation and extinction dynamics and the drivers of rate changes. Here, we analyze a continuous species-level fossil record of endemic diatoms from ancient Lake Ohrid, along with environmental and climate indicator time series since lake formation 1.36 million years (Ma) ago. We show that speciation and extinction rates nearly simultaneously decreased in the environmentally dynamic phase after ecosystem formation and stabilized after deep-water conditions established in Lake Ohrid. As the lake deepens, we also see a switch in the macroevolutionary trade-off, resulting in a transition from a volatile assemblage of short-lived endemic species to a stable community of long-lived species. Our results emphasize the importance of the interplay between environmental/climate change, ecosystem stability, and environmental limits to diversity for diversification processes. The study also provides a new understanding of evolutionary dynamics in long-lived ecosystems.", "keyphrases": ["evolutionary dynamic", "ecosystem", "limit", "speciation"]}
{"id": "paleo.006975", "title": "Taxonomic status of the caturid genera (Halecomorphi, Caturidae) and their Late Jurassic species", "abstract": "Caturids are among the best-known predatory ray-finned fishes of the Mesozoic. Although there is consensus about their sister-group relationship to Amiidae (Holostei, Amiiformes), their diversity, ingroup phylogenetic relationships and evolutionary history are still very poorly understood. Caturidae is currently restricted to Caturus and Amblysemius, each with two species. Among them, C. furcatus has become the wastebasket taxon for the group. Our revision of nearly 40 species based on the original descriptions, type and referred material led to significant results changing the picture of caturid diversity in the Late Jurassic. Four specific names are unavailable. Due to insufficient information in the original descriptions, lack of diagnostic features in the type material, or the complete lack of type material, 13 nominal species are nomina dubia. Two species currently considered junior synonyms represent distinct taxa. Strobilodus giganteus is removed from Caturidae. Caturus cliftoni, Thlattodus and Ditaxiiodus are tentatively referred to Strobilodus. The fossil record of Caturoidea is restricted to the Jurassic and earliest Cretaceous. The group apparently underwent significant diversification during the Late Jurassic, as indicated by the increase in the number of taxa and the dispersal of the group outside Europe, which had already begun in the Middle Jurassic.", "keyphrases": ["halecomorphi", "caturidae", "amiiformes", "caturoidea", "diversification"]}
{"id": "10.1080/02724634.1993.10011501", "title": "Anatomy and relationships of Haptodus garnettensis, a Pennsylvanian synapsid from Kansas", "abstract": "ABSTRACT New, well-preserved specimens of the Upper Pennsylvanian synapsid Haptodus garnettensis from Garnett, Kansas, represent more mature individuals than those available previously and indicate that H. garnettensis is diagnosed by several autapomorphies: septomaxilla with small facial exposure; prefrontal pocket shallow; pineal ridge present; supratemporal notched; anterior end of angular overlapped dorsally and ventrally by splenial; robust, chisel-shaped teeth; teeth present on palatal ramus of premaxilla. A phylogenetic analysis of early synapsids indicates that H. garnettensis is not a sphenacodontid.", "keyphrases": ["haptodus garnettensis", "synapsid", "skull"]}
{"id": "paleo.004588", "title": "Microstructural diversity of the stylophyllid (Scleractinia) skeleton", "abstract": "Coralla of the three species of solitary corals described herein from the Sinemurian (Lower Jurassic) of Sicily, i.e., Haimeicyclus haimei (Chapuis and Dewalque, 1853), Stylophyllopsis sp. cf. S. rugosa (Duncan and Wright, 1867), and Stylophyllopsis sp. A., conform to the overall stylophyllid morphology. Their septa consist of spines that are increasingly covered with sclerenchyme and low in the calice form compact blades. The pattern of diagenetic alteration of septa is diverse but consistent within particular taxa. It suggests that the spectrum of the original microstructures is wider than traditionally suggested for stylophyllids. In H. haimei, the septa are covered with dense granulations and completely recrystallized. Granulations also cover septal faces of Stylophyllopsis cf. rugosa and have rod-like foundations. In Stylophyllopsis sp. A., vestiges of the narrow mid-septal zone (similar to that in minitrabecular corals) occur in the proximal part of larger septa, whereas septal spines which are similar to those in Stylophyllopsis cf. rugosa occur in their distal parts. Similar diversity of microstructures is reported also in Triassic stylophyllids that have aragonitic coralla. The presence of distinct septal spines along with wide-ranging microstructural diversity of traditional Triassic-Jurassic stylophyllids, casts light on their possible evolutionary relationships, and can be a useful criterion for further revision of the group. For example, Jurassic thecocyathids, considered ancestral to caryophylliinans, share similar spiny/lobate septa with stylophyllids. Also Recent deep-water anthemiphylliids with spiny/lobate septa are strikingly similar to stylophyllids. Although this may be another example of parallel evolution, the separation of anthemiphylliids from other scleractinian clades on a mitochondrial 16S RNA tree topology suggests their ancient roots and enable us to suggest a stylophyllid ancestry. The supposed cyclic pattern of protoseptal insertion in Early Jurassic H. haimei supports the hypothesis of scleractinian-like (and not rugosan) ancestory of the stylophyllid evolutionary lineage.", "keyphrases": ["stylophyllid", "scleractinia", "coral", "deep-water", "microstructural diversity"]}
{"id": "10.1080/02724634.2018.1480113", "title": "A New Anisian (Middle Triassic) Eosauropterygian (Reptilia, Sauropterygia) from Panzhou, Guizhou Province, China", "abstract": "ABSTRACT Eosauropterygians rapidly diversified in the Anisian (Middle Triassic), a period by which the invertebrates had already completely recovered from the end-Permian mass extinction. The Pelsonian (Anisian) deposits of the small Panxian and Luoping intraplatform basins in southwestern China alone yielded seven or more eosauropterygian taxa. A new Middle Triassic sauropterygian, Panzhousaurus rotundirostris, gen. et sp. nov., is here described based on an almost complete skeleton from the middle Anisian (Middle Triassic) of Panzhou (Guizhou Province, southwestern China). The upper temporal fenestra smaller than the orbit, the broad and flat parietal table, the cervical ribs with two proximal articular heads, the pachyostotic proximal ends of the dorsal ribs, and the unexpanded sacral ribs indicate that the specimen is a pachypleurosaur-like eosauropterygian. The new species also shows some differences from all other eosauropterygians, such as a rounded and shortened snout, 24 cervical and 20 dorsal vertebrae, a straight ulna with a concave posterior margin, and four distal carpals. Phylogenetic analysis also reveals that Panzhousaurus is an eosauropterygian, closely related to pachypleurosaur-like forms. The discovery of Panzhousaurus enriches our knowledge of the diversity of the Panxian fauna and provides new information to test phylogenetic relationships among known eosauropterygians.", "keyphrases": ["middle triassic", "eosauropterygian", "southwestern china"]}
{"id": "10.1080/08912963.2017.1289519", "title": "A new species of Plesiodimylus (Dimylidae, Eulipotyphla, Mammalia) from the Early Miocene of Spain", "abstract": "Abstract We report a new dimylid species, Plesiodimylus ilercavonicus sp. nov., from the Early Miocene locality of Mas d\u2019Antolino B-5 (Ribesalbes-Alcora, Castell\u00f3, Spain). This new species of Plesiodimylus is an amblyodont form of the genus and exhibits some primitive characters. The phylogenetic and palaeoenvironmental implications of this southern occurrence of Plesiodimylus in Lower Miocene sediments are discussed. http://zoobank.org/lsid:zoobank.org:pub:E78DB979-6552-4BE2-BEC9-FA2EA05B7B39", "keyphrases": ["plesiodimylus", "mollusk group", "insectivore"]}
{"id": "10.1080/02724634.2015.1025956", "title": "Phylogeny of the Ichthyopterygia Incorporating Recent Discoveries from South China", "abstract": "ABSTRACT \n During the last decade, abundant ichthyopterygian material has been found from the Triassic of South China as well as the Upper Jurassic and Lower Cretaceous of Europe and South America, significantly expanding our knowledge of ichthyopterygian diversity through the Mesozoic. Previous phylogenetic hypotheses of the group no longer account for these extensive additions, necessitating a new phylogenetic framework for the entire Ichthyopterygia to enable evolutionary studies of the group. We present here a comprehensive phylogenetic hypothesis for Ichthyopterygia based on cladistic analysis of 163 characters coded for 59 ingroup and five outgroup taxa. The monophyly of Ichthyopterygia is strongly supported by a Bremer index value of 7. Five major groups of Ichthyopterygia during the Triassic, viz., Grippioidea, Cymbospondylidae, Mixosauridae, Shastasauridae, and Toretocnemidae, are well supported by Bremer index values between 3 and 5. Major clades that evolved in the Triassic, including Merriamosauria, Euichthyosauria, and Parvipelvia, are also robustly supported, whereas most post-Triassic clades are very weakly supported with a Bremer index value of 1, with a few exceptions, such as Thunnosauria and Ophthalmosauridae. The traditional Shastasauridae is expanded to comprise six genera but excludes Callawayia, which is more closely related to Parvipelvia than to Shastasauridae. \u2018C.\u2019 wolonggangensis is a shastasaurid but does not form a monophyletic clade with Callawayia neoscapularis or Guizhouichthyosaurus tangae as previously asserted. The new phylogenetic hypothesis is generally consistent with the stratigraphic occurrences of each taxon especially for the Triassic taxa.", "keyphrases": ["ichthyopterygia", "south china", "phylogenetic framework", "thunnosauria", "early triassic"]}
{"id": "paleo.004941", "title": "Temporal and phylogenetic evolution of the sauropod dinosaur body plan", "abstract": "The colossal size and body plan of sauropod dinosaurs are unparalleled in terrestrial vertebrates. However, to date, there have been only limited attempts to examine temporal and phylogenetic patterns in the sauropod bauplan. Here, we combine three-dimensional computational models with phylogenetic reconstructions to quantify the evolution of whole-body shape and body segment properties across the sauropod radiation. Limitations associated with the absence of soft tissue preservation in fossils result in large error bars about mean absolute body shape predictions. However, applying any consistent skeleton\u2009:\u2009body volume ratio to all taxa does yield changes in body shape that appear concurrent with major macroevolutionary events in sauropod history. A caudad shift in centre-of-mass (CoM) in Middle Triassic Saurischia, associated with the evolution of bipedalism in various dinosaur lineages, was reversed in Late Triassic sauropodomorphs. A craniad CoM shift coincided with the evolution of quadrupedalism in the Late Triassic, followed by a more striking craniad shift in Late Jurassic\u2013Cretaceous titanosauriforms, which included the largest sauropods. These craniad CoM shifts are strongly correlated with neck enlargement, a key innovation in sauropod evolution and pivotal to their gigantism. By creating a much larger feeding envelope, neck elongation is thought to have increased feeding efficiency and opened up trophic niches that were inaccessible to other herbivores. However, we find that relative neck size and CoM position are not strongly correlated with inferred feeding habits. Instead the craniad CoM positions of titanosauriforms appear closely linked with locomotion and environmental distributions, potentially contributing to the continued success of this group until the end-Cretaceous, with all other sauropods having gone extinct by the early Late Cretaceous.", "keyphrases": ["sauropod", "com", "striking craniad shift", "jurassic\u2013cretaceous titanosauriform", "body mass"]}
{"id": "paleo.007113", "title": "A new species of Clevosaurus (Lepidosauria: Rhynchocephalia) from the Upper Triassic of Rio Grande do sul, Brazil", "abstract": "Abstract:\u2002 Well\u2010preserved cranial remains of a small sphenodontian lepidosaur from the Upper Triassic Caturrita Formation of Rio Grande do Sul, Brazil, are the first record of the genus Clevosaurus Swinton, 1939 from South America. They represent a new species, Clevosaurus brasiliensis, which is distinguished by a very short antorbital region of the skull (corresponding to about 20 per cent of skull length) and the presence of teeth in addition to two longitudinal rows on the pterygoid. C.\u2003brasiliensis most closely resembles C.\u2003bairdi from the Lower Jurassic of Nova Scotia (Canada) and C.\u2003mcgilli from the Lower Jurassic of Yunnan (China). The discovery of Clevosaurus in the Upper Triassic of southern Brazil provides a significant range extension of this widely distributed sphenodontian genus. Along with other recent finds, it also suggests that there may have been less biotic provincialism among terrestrial vertebrates during the Late Triassic than has previously been assumed.", "keyphrases": ["clevosaurus", "upper triassic", "vertebrate"]}
{"id": "10.1126/science.aai9067", "title": "On the origin of modern humans: Asian perspectives", "abstract": "The peopling of Asia In recent years, there has been increasing focus on the paleoanthropology of Asia, particularly the migration patterns of early modern humans as they spread out of Africa. Bae et al. review the current state of the Late Pleistocene Asian human evolutionary record from archaeology, hominin paleontology, geochronology, genetics, and paleoclimatology. They evaluate single versus multiple dispersal models and southern versus the northern dispersal routes across the Asian continent. They also review behavioral and environmental variability and how these may have affected modern human dispersals and interactions with indigenous populations. Science, this issue p. eaai9067 BACKGROUND The earliest fossils of Homo sapiens are located in Africa and dated to the late Middle Pleistocene. At some point later, modern humans dispersed into Asia and reached the far-away locales of Europe, Australia, and eventually the Americas. Given that Neandertals, Denisovans, mid-Pleistocene Homo, and H. floresiensis were present in Asia before the appearance of modern humans, the timing and nature of the spread of modern humans across Eurasia continue to be subjects of intense debate. For instance, did modern humans replace the indigenous populations when moving into new regions? Alternatively, did population contact and interbreeding occur regularly? In terms of behavior, did technological innovations and symbolism facilitate dispersals of modern humans? For example, it is often assumed that only modern humans were capable of using watercraft and navigating to distant locations such as Australia and the Japanese archipelago\u2014destinations that would not have been visible to the naked eye from the departure points, even during glacial stages when sea levels would have been much lower. Moreover, what role did major climatic fluctuations and environmental events (e.g., the Toba volcanic super-eruption) play in the dispersal of modern humans across Asia? Did extirpations of groups occur regularly, and did extinctions of populations take place? Questions such as these are paramount in understanding hominin evolution and Late Pleistocene Asian paleoanthropology. ADVANCES An increasing number of multidisciplinary field and laboratory projects focused on archaeological sites and fossil localities from different areas of Asia are producing important findings, allowing researchers to address key evolutionary questions that have long perplexed the field. For instance, technological advances have increased our ability to successfully collect ancient DNA from hominin fossils, providing proof that interbreeding occurred on a somewhat regular basis. New finds of H. sapiens fossils, with increasingly secure dating associations, are emerging in different areas of Asia, some seemingly from the first half of the Late Pleistocene. Cultural variability discerned from archaeological studies indicates that modern human behaviors did not simply spread across Asia in a time-transgressive pattern. This regional variation, which is particularly distinct in Southeast Asia, could be related at least in part to environmental and ecological variation (e.g., Palearctic versus Oriental biogeographic zones). OUTLOOK Recent findings from archaeology, hominin paleontology, geochronology, and genetics indicate that the strict \u201cout of Africa\u201d model, which posits that there was only a single dispersal into Eurasia at ~60,000 years ago, is in need of revision. In particular, a multiple-dispersal model, perhaps beginning at the advent of the Late Pleistocene, needs to be examined more closely. An increasingly robust record from Late Pleistocene Asian paleoanthropology is helping to build and establish new views about the origin and dispersal of modern humans. Map of sites with ages and postulated early and later pathways associated with modern humans dispersing across Asia during the Late Pleistocene. Regions of assumed genetic admixture are also shown. ka, thousand years ago. The traditional \u201cout of Africa\u201d model, which posits a dispersal of modern Homo sapiens across Eurasia as a single wave at ~60,000 years ago and the subsequent replacement of all indigenous populations, is in need of revision. Recent discoveries from archaeology, hominin paleontology, geochronology, genetics, and paleoenvironmental studies have contributed to a better understanding of the Late Pleistocene record in Asia. Important findings highlighted here include growing evidence for multiple dispersals predating 60,000 years ago in regions such as southern and eastern Asia. Modern humans moving into Asia met Neandertals, Denisovans, mid-Pleistocene Homo, and possibly H. floresiensis, with some degree of interbreeding occurring. These early human dispersals, which left at least some genetic traces in modern populations, indicate that later replacements were not wholesale.", "keyphrases": ["modern human", "africa", "late pleistocene", "subject"]}
{"id": "10.1111/pala.12453", "title": "The evolution of the modern avian digestive system: insights from paravian fossils from the Yanliao and Jehol biotas", "abstract": "The avian digestive system, like other aspects of avian biology, is highly modified relative to other reptiles. Together these modifications have imparted the great success of Neornithes, the most diverse clade of amniotes alive today. It is important to understand when and how aspects of the modern avian digestive system evolved among neornithine ancestors in order to elucidate the evolutionary success of this important clade and to understand the biology of stem birds and their closest dinosaurian relatives: Mesozoic Paraves. Although direct preservation of the soft tissue of the digestive system has not yet been reported, ingested remains and their anatomical location preserved in articulated fossils hint at the structure of the digestive system and its abilities. Almost all data concerning direct evidence of diet in Paraves comes from either the Upper Jurassic Yanliao Biota or the Lower Cretaceous Jehol Biota, both of which are known from deposits in north\u2010eastern China. Here, the sum of the data gleaned from the thousands of exceptionally well\u2010preserved fossils of paravians is interpreted with regards to the structure and evolution of the highly modified avian digestive system and feeding apparatus. This information suggests intrinsic differences between closely related stem lineages implying either strong homoplasy or that diet in each lineage of non\u2010ornithuromorph birds was highly specialized. Regardless, modern digestive capabilities appear to be limited to the Ornithuromorpha, although the complete set of derived feeding related characters is restricted to the Neornithes.", "keyphrases": ["avian digestive system", "biology", "stem bird"]}
{"id": "10.1073/pnas.111069498", "title": "Insect herbivory, plant defense, and early Cenozoic climate change", "abstract": "Insect damage on fossil leaves from the Central Rocky Mountains, United States, documents the response of herbivores to changing regional climates and vegetation during the late Paleocene (humid, warm temperate to subtropical, predominantly deciduous), early Eocene (humid subtropical, mixed deciduous and evergreen), and middle Eocene (seasonally dry, subtropical, mixed deciduous and thick-leaved evergreen). During all three time periods, greater herbivory occurred on taxa considered to have short rather than long leaf life spans, consistent with studies in living forests that demonstrate the insect resistance of long-lived, thick leaves. Variance in herbivory frequency and diversity was highest during the middle Eocene, indicating the increased representation of two distinct herbivory syndromes: one for taxa with deciduous, palatable foliage, and the other for hosts with evergreen, thick-textured, small leaves characterized by elevated insect resistance. Leaf galling, which is negatively correlated with moisture today, apparently increased during the middle Eocene, whereas leaf mining decreased.", "keyphrases": ["herbivory", "fossil leave", "frequency"]}
{"id": "paleo.008531", "title": "Paleobiology of the Latest Tithonian (Late Jurassic) Ammonite Salinites grossicostatum Inferred from Internal and External Shell Parameters", "abstract": "Based on material from the uppermost Tithonian La Caja Formation at Puerto Pi\u00f1ones, northeastern Mexico, the complete ontogenetic development (protoconch to adult) of the ammonite Salinites grossicostatum is outlined by a detailed morphometrical shell analysis. The embryonic stage, consisting of a small ellipsoid protoconch and ammonitella, ends at about 0.6 mm. Four major morphological changes are differentiated throughout ontogeny based on internal features such as reduced septal spacing and siphuncle position. Sexual dimorphism is reflected by shell size, siphuncular diameter, differences in the morphology of the apophysis, and by two distinct general trends in septal spacing. In addition, macroconchs are characterized by septal crowding at different stages, followed by the return to normal septum distances. Our analysis indicates a change in the mode of life after the neanic stage. A change in habitat preference is inferred for adult individuals. While microconchs persisted at Puerto Pi\u00f1ones, large mature macroconchs temporarily migrated to other areas, possibly for egg deposition. Salinites grossicostatum is endemic to the ancient Gulf of Mexico and is there restricted to outer continental shelf environments.", "keyphrases": ["ammonite salinites grossicostatum", "ammonoid", "two-dimensional measurement"]}
{"id": "10.1073/pnas.1416252111", "title": "The birth of a dinosaur footprint: Subsurface 3D motion reconstruction and discrete element simulation reveal track ontogeny", "abstract": "Significance We reconstructed the 3D foot movements of guineafowl traversing a granular substrate from biplanar X-rays, and then incorporated those kinematics into a discrete element simulation. Digital track models permitted visualization of in vivo track formation at the surface and at virtual bedding planes for the first time. Application of these volumetric data to fossil dinosaur tracks uncovered the developmental origin of previously enigmatic features. A \u201ctrack ontogeny\u201d perspective helps integrate limb and substrate dynamics into the interpretation of track morphology, from which foot anatomy cannot be read directly. Locomotion over deformable substrates is a common occurrence in nature. Footprints represent sedimentary distortions that provide anatomical, functional, and behavioral insights into trackmaker biology. The interpretation of such evidence can be challenging, however, particularly for fossil tracks recovered at bedding planes below the originally exposed surface. Even in living animals, the complex dynamics that give rise to footprint morphology are obscured by both foot and sediment opacity, which conceals animal\u2013substrate and substrate\u2013substrate interactions. We used X-ray reconstruction of moving morphology (XROMM) to image and animate the hind limb skeleton of a chicken-like bird traversing a dry, granular material. Foot movement differed significantly from walking on solid ground; the longest toe penetrated to a depth of \u223c5 cm, reaching an angle of 30\u00b0 below horizontal before slipping backward on withdrawal. The 3D kinematic data were integrated into a validated substrate simulation using the discrete element method (DEM) to create a quantitative model of limb-induced substrate deformation. Simulation revealed that despite sediment collapse yielding poor quality tracks at the air\u2013substrate interface, subsurface displacements maintain a high level of organization owing to grain\u2013grain support. Splitting the substrate volume along \u201cvirtual bedding planes\u201d exposed prints that more closely resembled the foot and could easily be mistaken for shallow tracks. DEM data elucidate how highly localized deformations associated with foot entry and exit generate specific features in the final tracks, a temporal sequence that we term \u201ctrack ontogeny.\u201d This combination of methodologies fosters a synthesis between the surface/layer-based perspective prevalent in paleontology and the particle/volume-based perspective essential for a mechanistic understanding of sediment redistribution during track formation.", "keyphrases": ["discrete element simulation", "track ontogeny", "foot", "substrate", "depth"]}
{"id": "paleo.001994", "title": "Devonian events: examples from the eastern Palaeotethys (Si Phai section, NE Vietnam)", "abstract": "Recent study of Middle to Upper Devonian deposits in the Dong Van area, northeast Vietnam, has revealed new, more detailed information of both the stratigraphic record of the Si Phai section and global Devonian bioevents. Four possible equivalents of well-known Devonian events of different magnitude were found in Vietnam, an area which is underrepresented in that respect: the (?) Ka\u010d\u00e1k Event, the (?)pumilio Events, the late Middle Givetian Taghanic Event and the Frasnian/Famennian Kellwasser Event. The stratigraphic framework of the Si Phai section allows us to recognise and assess the timing of global Devonian bioevents in Vietnam even though the section is not continuous. An overview of the sedimentological development of the Si Phai section is discussed briefly where carbonates in the section are composed of argillaceous limestones suggesting relatively deep, off-shore conditions. Due to the facies setting, the macrofauna is generally rare and the conodont record is likewise limited in some parts. Nevertheless, it is possible to pinpoint some global event intervals for the first time in Vietnam.\nKeywords Devonian events . Palaeotethys . Vietnam .\nThis article is a contribution to the special issue BClimate change and biodiversity patterns in the mid-Palaeozoic*", "keyphrases": ["dong van area", "devonian event", "southeast asia", "chinese border", "more data"]}
{"id": "paleo.008287", "title": "Evolution of retiolitid graptolites-a synopsis", "abstract": "Twenty million years of retiolitid evolution reflect environmental changes, the most severe being the Silurian Cyrtograptus lundgreni Event. Five biostratigraphically and morphologically constrained retiolitid faunas are distinguished and characterized according to their rhabdosomal modifications: (1) the oldest and long-ranging Llandovery group of mostly large and morphologically complex rhabdosomes, (2) the less diverse Telychian-Sheinwoodian group, (3) the Cyrtograptus lundgreni Biozone varied group of intermediate size, and two short-ranged (4) late Homerian, and (5) early Ludlow groups with small rhabdosomes. Although the evolutionary history of retiolitids was complex and not linear, a common tendency toward reduction of rhabdosome size in most lineages is observed. The greatest reduction in both number and volume of thecae, and in skeletal elements is demonstrated in the Gothograptus and Plectograptus faunas. Contrary to the thecal decrease, a distinctive increase of sicula size is observed in retiolitids. Two types of colonies are distinguished: L-colonies with a small sicula and numerous large thecae of similar size, and S-colonies with a long sicula and a few, small thecae. These changes imply modification of the soft body: an increase in siculozooid length and a decrease in the size of the zooids. Thus, the siculozooid probably produced great amounts of morphogen inhibiting zooid growth. In consequence the phenomenon of colony reduction occurred. The most extreme stages of rhabdosome reduction in Ludlow retiolitids can be seen in Plectodinemagraptus gracilis of the Plectograptus lineage and in the new species Holoretiolites helenaewitoldi, possibly representing the last stage of skeletal reduction in the Gothograptus lineage; the next hypothetical stage would be its total loss. The sicula length of Holoretiolites, about 2 mm, is reported herein for the first time.", "keyphrases": ["silurian", "holoretiolites", "tubarium construction"]}
{"id": "10.1144/SP455.18", "title": "New perspectives on pterosaur palaeobiology", "abstract": "Abstract Pterosaurs were the first vertebrates to evolve powered flight and occupied the skies of the Mesozoic for 160 million years. They occurred on every continent, evolved their incredible proportions and anatomy into well over 100 species, and included the largest flying animals of all time among their ranks. Pterosaurs are undergoing a long-running scientific renaissance that has seen elevated interest from a new generation of palaeontologists, contributions from scientists working all over the world and major advances in our understanding of their palaeobiology. They have especially benefited from the application of new investigative techniques applied to historical specimens and the discovery of new material, including detailed insights into their fragile skeletons and their soft tissue anatomy. Many aspects of pterosaur science remain controversial, mainly due to the investigative challenges presented by their fragmentary, fragile fossils and notoriously patchy fossil record. With perseverance, these controversies are being resolved and our understanding of flying reptiles is increasing. This volume brings together a diverse set of papers on numerous aspects of the biology of these fascinating reptiles, including discussions of pterosaur ecology, flight, ontogeny, bony and soft tissue anatomy, distribution and evolution, as well as revisions of their taxonomy and relationships.", "keyphrases": ["pterosaur", "palaeobiology", "first vertebrate", "world"]}
{"id": "10.1017/S1477201906001970", "title": "Early dinosaurs: A phylogenetic study", "abstract": "Synopsis Early dinosaur evolution has been the subject of several phylogenetic studies and the position of certain basal forms is currently debated. This is the case for the oldest known members of the group, excavated from the Late Triassic Ischigualastian beds of South America, such as Herrerasaurus, Eoraptor, Pisanosaurus, Saturnalia and Staurikosaurus. A new cladistic analysis of the early dinosaur radiation was performed to assess the relationships among the three major clades (Ornithischia, Sauropodomorpha and Theropoda) and to define the phylogenetic position of the basal members of the group. The most parsimonious hypothesis has Silesaurus opolensis as the sister taxon to a dichotomy including monophyletic Saurischia and Ornithischia. The latter includes Pisanosaurus mertii, and the former all other well\u2010known Triassic dinosaurs. Saurischia is composed of two major monophyletic groups: Herrerasauridae (including Herrerasaurus ischigualastensis and Staurikosaurus pricei) and Eusaurischia (including the theropod and sauropodomorph lineages), while Eoraptor lunensis appears to represent the sister taxon to Eusaurischia. Saturnalia tupiniquim is a stem\u2010taxon to Sauropodomorpha and Guaibasaurus candelariensis might belong to the theropod branch. Some of these hypotheses are, however, not strongly supported. Especially uncertain are the affinities of Silesaurus and Guaibasaurus. The latter can only be safely regarded as a saurischian, while the former might belong to the ornithischian lineage. The dinosaurian affinities of Eoraptor and Herrerasauridae are strongly supported. Yet, the possibility that they (especially Eoraptor) represent basal theropods, rather than basal saurischians, cannot be dismissed. In fact, basal saurischian evolution is still too poorly understood for a definitive hypothesis of relationships to be presented.", "keyphrases": ["phylogenetic study", "late triassic", "silesaurus", "archosaur"]}
{"id": "10.1080/14772019.2019.1605411", "title": "The trilobite Redlichia from the lower Cambrian Emu Bay Shale Konservat-Lagerst\u00e4tte of South Australia: systematics, ontogeny and soft-part anatomy", "abstract": "The trilobite Redlichia Cossmann, 1902 is an abundant element of the lower Cambrian (Series 2, Stage 4) Emu Bay Shale (EBS) Konservat-Lagerst\u00e4tte on Kangaroo Island, South Australia. Well-preserved, fully articulated specimens from this deposit are known to reach lengths of up to 25\u2009cm, representing one of the largest known Cambrian trilobites. Until now, all Redlichia specimens from the EBS have been referred to Redlichia takooensis Lu, 1950, a species originally described from South China. Previous work recognized considerable differences in exoskeletal morphology among specimens of varying sizes, which was attributed to ontogeny. However, close examination of a large collection of recently acquired specimens shows that this variation actually represents two distinct morphs, interpreted here as separate species: R. takooensis, and a large, new species, Redlichia rex sp. nov. An analysis of morphological variation in holaspides (\u2018adults\u2019) of the more common R. takooensis reveals considerable ontogenetic change occurred even during this later phase of growth. Some specimens of both Redlichia species from the EBS also exhibit exceptionally preserved soft-part anatomy, particularly the antennae and biramous appendages. Here, appendages (antenniform and biramous) and digestive structures are described, and biramous appendage reconstructions of R. rex sp. nov. are presented, which show a striking resemblance to some early Cambrian trilobites from South China. In particular, R. rex has a tripartite exopodite, as well as a dorsoventrally deep protopodite with gnathobasic spines used to shred or crush food items. Based on recent phylogenetic analyses, it is possible that an exopodite with tripartite subdivisions represents the plesiomorphic condition for Artiopoda (trilobites and kin). The digestive system of R. takooensis exhibits a series of paired digestive glands in the cephalon and anterior thorax, similar to those described for a number of other Cambrian and Ordovician trilobites. http://zoobank.org/urn:lsid:zoobank.org:pub:507BEAFC-4AFA-43F4-A5C4-49E4B58C658E", "keyphrases": ["emu bay shale", "south australia", "ontogeny", "soft-part anatomy", "morphology"]}
{"id": "paleo.000066", "title": "The brachiopod Eoobolus from the Early Cambrian Mural Formation (Canadian Rocky Mountains)", "abstract": "The Early Cambrian brachiopod, Eoobolus, is one of the first representatives of the superfamily, Linguloidea, the defining characteristics of which include the classical morphology of oval shells and a pedicle that emerges from between the two valves. The material described here from the Mural Formation (Jasper National Park, Canadian Rocky Mountains) provides well-preserved muscle scars and larval shells that allow a discussion of the muscle system and the larval morphology of Eoobolus. The dorsal larval shell exhibits a morphology similar to other Cambrian linguloids, but also to paterinids, Mickwitzia muralensis, and some rhynchonelliforms. This suggests that there was a lesser degree of disparity among brachiopod larvae in the Cambrian than there is today. The muscle system of Eoobolus is similar to other linguloids, but differs from that of Recent lingulids and discinids by having one or two more pairs of oblique muscles. New data on the distribution of features characteristic of the family Eoobolidae question the validity of this family.", "keyphrases": ["brachiopod", "eoobolus", "mural formation", "canadian rocky mountains", "larvae"]}
{"id": "10.1098/rsta.2017.0085", "title": "Greenhouse- and orbital-forced climate extremes during the early Eocene", "abstract": "The Palaeocene\u2013Eocene Thermal Maximum (PETM) was a significant global warming event in Earth's deep past (56\u2009Mya). The warming across the PETM boundary was driven by a rapid rise in greenhouse gases. The event also coincided with a time of maximum insolation in Northern Hemisphere summer. There is increased evidence that the mean warming was accompanied by enhanced seasonality and/or extremes in precipitation (and flooding) and drought. A high horizontal resolution (50\u2009km) global climate model is used to explore changes in the seasonal cycle of surface temperature, precipitation, evaporation minus precipitation and river run-off for regions where proxy data are available. Comparison for the regions indicates the model accurately simulates the observed changes in these climatic characteristics with North American interior warming and drying, and warming and increased river run-off at other regions. The addition of maximum insolation in Northern Hemisphere summer leads to a drier North America, but wetter conditions at most other locations. Long-range transport of atmospheric moisture plays a critical role in explaining regional changes in the water cycle. Such high-frequency variations in precipitation might also help explain discrepancies or misinterpretation of some climate proxies from the same locations, especially where sampling is coarse, i.e. at or greater than the frequency of precession. This article is part of a discussion meeting issue \u2018Hyperthermals: rapid and extreme global warming in our geological past\u2019.", "keyphrases": ["petm", "climate model", "hydrologic cycle"]}
{"id": "paleo.005049", "title": "Five hundred million years of extinction and recovery: a phanerozoic survey of large\u2010scale diversity patterns in fishes", "abstract": "Abstract:\u2002 Fishes include more than half of all living animals with backbones, but large\u2010scale palaeobiological patterns in this assemblage have not received the same attention as those for terrestrial vertebrates. Previous surveys of the fish record have generally been anecdotal, or limited either in their stratigraphic or in their taxonomic scope. Here, we provide a broad overview of the Phanerozoic history of fish diversity, placing a special emphasis on intervals of turnover, evolutionary radiation, and extinction. In particular, we provide in\u2010depth reviews of changes during, and ecological and evolutionary recovery after, the end\u2010Devonian (Hangenberg) and Cretaceous\u2013Palaeogene (K\u2013Pg) extinctions.", "keyphrases": ["recovery", "fish diversity", "diversification", "devonian"]}
{"id": "paleo.006957", "title": "The stratigraphy of mass extinction", "abstract": "Patterns of last occurrences of fossil species are often used to infer the tempo and timing of mass extinction, even though last occurrences generally precede the time of extinction. Numerical simulations with constant extinction demonstrate that last occurrences are not randomly distributed, but tend to cluster at subaerial unconformities, surfaces of forced regression, flooding surfaces and intervals of stratigraphical condensation, all of which occur in predictable stratigraphical positions. This clustering arises not only from hiatuses and non\u2010deposition, but also from changes in water depth. Simulations with intervals of elevated extinction cause such clusters of last occurrences to be enhanced within and below the interval of extinction, suggesting that the timing and magnitude of extinctions in these instances could be misinterpreted. With the possible exception of the end\u2010Cretaceous, mass extinctions in the fossil record are characterized by clusters of last occurrences at these sequence stratigraphical horizons. Although these clusters of last occurrences may represent brief pulses of elevated extinction, they are equally likely to form by stratigraphical processes during a protracted period (more than several hundred thousand years) of elevated extinction rate. Geochemical proxies of extinction causes are also affected similarly, suggesting that many local expressions of mass extinction should be re\u2010evaluated for the timing of extinction and its relation to environmental change. We propose three tests for distinguishing pulses of extinction from clusters of last occurrences produced by stratigraphical processes.", "keyphrases": ["mass extinction", "simulation", "cluster", "regression", "stratigraphic architecture"]}
{"id": "10.1002/spp2.1303", "title": "The overlooked aquatic green algal component of early terrestrial environments: Triskelia scotlandica gen. et sp. nov. from the Rhynie cherts", "abstract": "As a large majority of modern green algae are freshwater rather than marine, it can be hypothesized that algae were an important component of early terrestrial environments. However, this component remains overlooked as algal affinities are difficult to decipher, due to the lack of distinctive characters observable in standard light microscopy. Herein, we use a new approach to studying microfossils from the Devonian (407 Ma) Rhynie cherts, renowned as one of the earliest exceptionally preserved terrestrial ecosystem. Using data from confocal laser scanning microscopy, the microfossils were reconstructed in 3D allowing us to gather information on morphological and physiological traits. We document Triskelia scotlandica gen. et sp. nov., which is the resting stage of a new species of microalgae. Numerous individuals were discovered preserved inside the remains of a flooded plant aerial axis. They are shown to be spheroidal to ellipsoidal walled cells, with a pseudo\u2010reticulate surface ornamentation and occasional large openings probably resulting from the germination process. We draw comparison with fossil and modern microorganisms demonstrating morphological convergences in wall ornament and physiological traits, especially with zygospores of modern Chlorophyta. Our description of Triskelia leads us to critically evaluate the Rhynie chert fossils Cymatiosphaera and Pterospermella. We conclude that it is unlikely that the Rhynie cherts contained prasinophycean algae of these types. We suggest that our microfossils are Chlorophyta (green algae) incertae sedis that were highly adapted to the special ecological conditions encountered in a geothermal wetland.", "keyphrases": ["early terrestrial environment", "green algae", "chlorophyta"]}
{"id": "10.1144/GSL.SP.2000.179.01.03", "title": "The Late Palaeozoic relations between Gondwana and Laurussia", "abstract": "Abstract Reconstructions based on biogeography, palaeomagnetism and facies distributions indicate that, in later Palaeozoic time, there were no wide oceans separating the major continents. During the Silurian and Early Devonian time, many oceans became narrower so that only the less mobile animals and plants remained district. There were several continental collisions: the Tornquist Sea (between Baltica and Avalonia) closed in Late Ordovician time, the Iapetus Ocean (between Laurentia and the newly merged continents of Baltica and Avalonia) closed in Silurian time, and the Rheic Ocean (between Avalonia and Gondwana and the separate parts of the Armorican Terrane Assemblage) closed (at least partially) towards the end of Early Devonian time. Each of these closures was reflected by migrations of non-marine plants and animals as well as by contemporary deformation. New maps, based on palaeomagnetic and faunal data, indicate that Gondwana was close to Laurussia during the Devonian and Carboniferous periods, with fragments of Bohemia and other parts of the Armorican Terrane Assemblage interspersed between. It follows that, after Early Devonian time, the Variscan oceans of central Europe can never have been very wide. The tectonic evolution of Europe during Devonian and Carboniferous time was thus more comparable with the present-day Mediterranean Sea than with the Pacific Ocean.", "keyphrases": ["gondwana", "laurussia", "rheic ocean"]}
{"id": "10.26879/320", "title": "Fruits, seeds, and flowers from the Warman clay pit (middle Eocene Claiborne Group), western Tennessee, USA", "abstract": "In this report, we examine fossil plant reproductive materials from the Warman clay pit in western Tennessee. The investigation of about 600 specimens has resulted in the recognition of 60 species and morphotypes. Based upon comparisons of gross morphology of these specimens with available extant plant materials and the literature, we have been able to assess their affinities with 16 extant families. We are able to relate 36 species and morphotypes to the following families: Altingiaceae, Annonaceae, Araceae, Araliaceae, Bignoniaceae, Euphorbiaceae, Fabaceae, Fagaceae, Hamamelidaceae, Juglandaceae, Lauraceae, Magnoliaceae, Malpighiaceae, Moraceae, Oleaceae, and Theaceae. In addition, 24 morphotypes are not assigned to any family due to the limited number of diagnostic characters. This report represents a comprehensive review on the reproductive materials from a single locality of the Claiborne Group of the southeastern United States. Compared to traditional investigations focused primarily on leaves, this study provides a different perspective for understanding plant diversity for the middle Eocene Claiborne Group. Hongshan Wang. Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA hwang@flmnh.ufl.edu Jane Blanchard. Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611, USA Ojjhblanchard@aol.com David L. Dilcher. Departments of Biology and Geology, Indiana University, Bloomington, Indiana 47405, USA dilcher@indiana.edu", "keyphrases": ["warman clay pit", "western tennessee", "usa", "reproductive material", "morphotype"]}
{"id": "10.1073/pnas.0801507105", "title": "Dating the late prehistoric dispersal of Polynesians to New Zealand using the commensal Pacific rat", "abstract": "The pristine island ecosystems of East Polynesia were among the last places on Earth settled by prehistoric people, and their colonization triggered a devastating transformation. Overhunting contributed to widespread faunal extinctions and the decline of marine megafauna, fires destroyed lowland forests, and the introduction of the omnivorous Pacific rat (Rattus exulans) led to a new wave of predation on the biota. East Polynesian islands preserve exceptionally detailed records of the initial prehistoric impacts on highly vulnerable ecosystems, but nearly all such studies are clouded by persistent controversies over the timing of initial human colonization, which has resulted in proposed settlement chronologies varying from \u2248200 B.C. to 1000 A.D. or younger. Such differences underpin radically divergent interpretations of human dispersal from West Polynesia and of ecological and social transformation in East Polynesia and ultimately obfuscate the timing and patterns of this process. Using New Zealand as an example, we provide a reliable approach for accurately dating initial human colonization on Pacific islands by radiocarbon dating the arrival of the Pacific rat. Radiocarbon dates on distinctive rat-gnawed seeds and rat bones show that the Pacific rat was introduced to both main islands of New Zealand \u22481280 A.D., a millennium later than previously assumed. This matches with the earliest-dated archaeological sites, human-induced faunal extinctions, and deforestation, implying there was no long period of invisibility in either the archaeological or palaeoecological records.", "keyphrases": ["dispersal", "new zealand", "east polynesia", "people"]}
{"id": "10.1017/S0094837300015918", "title": "Time and taphonomy: quantitative estimates of time-averaging and stratigraphic disorder in a shallow marine habitat", "abstract": "We examined the radiocarbon age, taphonomic condition and stratigraphic position of shells of the venerid bivalve Chione spp. from the tidal flats of Bahia la Choya, Sonora, Mexico. Shells in Bahia la Choya are time-averaged. Thirty shells yielded radiocarbon dates from modern (A.D. 1950 or younger) to 3569 years before present. The median calendar age of inner flat shells is 483 years; the median age of tidal channel shells is 427 years. We interpret such long shell survival to be the result of frequent shallow burial. Such burial retards bioerosion of shells. The taphonomic condition of shells varied with environment. Shells from the surface of the inner flats were better preserved than shells from the tidal channel. Shells are more likely to be physically worn and biologically degraded in the waters of the channel than on the quieter and more frequently exposed inner tidal flat. Taphonomic condition is an unreliable indicator of a shell's time-since-death. Poorly-preserved shells on the inner flats tended to be old, but in general shell condition was much more variable than shell age. A shell's condition is more likely the result of its total residence time on the surface than its time-since-death (surface time plus burial time). Two composite short (44 cm and 50 cm) cores revealed varying degrees of stratigraphic disorder (the departure from perfect correlation between relative stratigraphic position and relative age). One of eight shells in the inner flats core was disordered; four of nine shells in the tidal channel were disordered. The actual age range of surface shells approximates the age range of shells in cores. Stratigraphic disorder is a consequence of both time-averaging and physical and biogenic mixing. Time-averaging controls the degree of precision possible in paleoecological studies. Environmental changes and ecological phenomena occurring within a span of 3500 years would not be recognized in deposits like those of Bahia la Choya. Time-averaging and stratigraphic disorder also constrain the temporal resolution possible in microstratigraphic studies of evolution. The extent of time-averaging and stratigraphic disorder will dictate an appropriate sample interval. In order to prevent temporal overlap between successive samples in deposits like Bahia la Choya, sample spacing should not be less than approximately 0.5 m.", "keyphrases": ["time-averaging", "stratigraphic disorder", "mixing", "fossil assemblage"]}
{"id": "10.1130/G23117A.1", "title": "Smithian-Spathian boundary event: Evidence for global climatic change in the wake of the end-Permian biotic crisis", "abstract": "One of the most important carbon cycle perturbations following the end-Permian mass extinction event straddles the Smithian-Spathian boundary (SSB) (Olenekian, Early Triassic). This anomaly is characterized by a prominent positive carbon isotope excursion known from Tethyan marine rocks. Its global signifi cance is established here by a new high paleolatitude record (Spitsbergen). Paleontological evidence, such as Boreal palynological data (Barents Sea, Norway) and global patterns of ammonoid distribution, indicates a synchronous major change in terrestrial and marine ecosystems near the SSB. The reestablishment of highly diverse plant ecosystems, including the rise of woody gymnosperms and decline of the formerly dominating lycopods, is interpreted as an effect of a major climate change. This hypothesis is supported by modeling of ammonoid paleobiogeography, the distribution patterns of which are interpreted as a proxy for sea surface temperatures (SST). The latest Smithian thus appears to have been a time of a warm and equable climate as expressed by an almost fl at pole to equator SST gradient. In contrast, the steep Spathian SST gradient suggests latitudinally differentiated climatic conditions. We propose that this drastic climate change and the global carbon cycle perturbation were triggered by a massive end-Smithian CO2 injection. The SSB event could therefore represent one of the causes for stepwise and delayed recovery of marine and terrestrial biotas in the wake of the end-Permian biotic crisis.", "keyphrases": ["end-permian biotic crisis", "early triassic", "smithian-spathian boundary"]}
{"id": "paleo.001124", "title": "Functional anatomy of the cervical region in the late Miocene amphicyonid Magericyon anceps (Carnivora, Amphicyonidae): implications for its feeding behaviour", "abstract": "We describe the skull and neck morphology of the late Miocene amphicyonid Magericyon anceps, focusing on aspects related to functional anatomy. This species, recorded only from the Vallesian sites of Batallones\u20101 and Batallones\u20103 (Madrid, Spain), is the last known amphicyonid in the fossil record of Western Europe, with the Batallones populations being one of the best\u2010known of the family. The morphology of its skull and cervical vertebrae allows us to infer aspects of its associated musculature, such as muscle strength and range of movement. Magericyon anceps had well\u2010developed neck muscles, suited for providing the head with a high capacity for lateral and rotatory movements, as well as for playing an important role in the extension and stabilization of the head and neck, improving its efficiency in killing and consuming prey. Magericyon anceps shared its habitat with other large carnivorans, which would have strongly influenced its behaviour. Rapid killing and processing of prey would have been an advantage for avoiding kleptoparasitism by other large predators, as well as reducing consumption time, during which M. anceps would have been more vulnerable to attack from competitors.", "keyphrases": ["amphicyonid", "skull", "functional anatomy"]}
{"id": "paleo.000881", "title": "Reassessment of the Evidence for Postcranial Skeletal Pneumaticity in Triassic Archosaurs, and the Early Evolution of the Avian Respiratory System", "abstract": "Uniquely among extant vertebrates, birds possess complex respiratory systems characterised by the combination of small, rigid lungs, extensive pulmonary air sacs that possess diverticula that invade (pneumatise) the postcranial skeleton, unidirectional ventilation of the lungs, and efficient crosscurrent gas exchange. Crocodilians, the only other living archosaurs, also possess unidirectional lung ventilation, but lack true air sacs and postcranial skeletal pneumaticity (PSP). PSP can be used to infer the presence of avian-like pulmonary air sacs in several extinct archosaur clades (non-avian theropod dinosaurs, sauropod dinosaurs and pterosaurs). However, the evolution of respiratory systems in other archosaurs, especially in the lineage leading to crocodilians, is poorly documented. Here, we use \u00b5CT-scanning to investigate the vertebral anatomy of Triassic archosaur taxa, from both the avian and crocodilian lineages as well as non-archosaurian diapsid outgroups. Our results confirm previous suggestions that unambiguous evidence of PSP (presence of internal pneumatic cavities linked to the exterior by foramina) is found only in bird-line (ornithodiran) archosaurs. We propose that pulmonary air sacs were present in the common ancestor of Ornithodira and may have been subsequently lost or reduced in some members of the clade (notably in ornithischian dinosaurs). The development of these avian-like respiratory features might have been linked to inferred increases in activity levels among ornithodirans. By contrast, no crocodile-line archosaur (pseudosuchian) exhibits evidence for unambiguous PSP, but many of these taxa possess the complex array of vertebral laminae and fossae that always accompany the presence of air sacs in ornithodirans. These laminae and fossae are likely homologous with those in ornithodirans, which suggests the need for further investigation of the hypothesis that a reduced, or non-invasive, system of pulmonary air sacs may be have been present in these taxa (and secondarily lost in extant crocodilians) and was potentially primitive for Archosauria as a whole.", "keyphrases": ["postcranial skeletal pneumaticity", "pterosaur", "outgroup", "foramina", "ornithodira"]}
{"id": "10.1080/02724634.2010.483553", "title": "The systematic position of Anourosoricini (Soricidae, Mammalia): paleontological and molecular evidence", "abstract": "ABSTRACT Two late middle Miocene to early late Miocene (12\u201311 Ma) soricid populations from Spain and Germany are re-described and assigned to Crusafontina and Darocasorex, gen. et sp. nov., primitive genera within the Anourosoricini. The relatively advanced morphology of these oldest Anourosoricini genera known suggest a much earlier date for the origin of the tribe. Molecular phylogenetics support an early origin (\u223c15 Ma), but ages up to \u223c18 Ma are possible after re-evaluating the calibration points that use early\u2013middle Miocene occurrences of Soricinae and their potential ancestors. Both molecular phylogenetics and paleontology consistently point to Anourosoricini being the sister clade of the combined Nectogalini and Notiosoricini. Synapomorphies in morphology relate to the condylar structure, the morphology of the lower premolar (p4) and reduction of the upper antemolars. The phylogenetic roots of the Anourosoricini within the Soricinae will remain elusive until more early\u2013middle Miocene rests are found. The paucity of fossils is probably related to the lack of terrestrial sedimentary rocks at northern latitudes, where primitive Anourosoricini and their soricine ancestors might have been residing during the early\u2013middle Miocene thermal optimum.", "keyphrases": ["anourosoricini", "soricidae", "tribe"]}
{"id": "10.1093/molbev/msg226", "title": "Bayesian models of episodic evolution support a late precambrian explosive diversification of the Metazoa.", "abstract": "Multicellular animals, or Metazoa, appear in the fossil records between 575 and 509 million years ago (MYA). At odds with paleontological evidence, molecular estimates of basal metazoan divergences have been consistently older than 700 MYA. However, those date estimates were based on the molecular clock hypothesis, which is almost always violated. To relax this hypothesis, we have implemented a Bayesian approach to describe the change of evolutionary rate over time. Analysis of 22 genes from the nuclear and the mitochondrial genomes under the molecular clock assumption produced old date estimates, similar to those from previous studies. However, by allowing rates to vary in time and by taking small species-sampling fractions into account, we obtained much younger estimates, broadly consistent with the fossil records. In particular, the date of protostome-deuterostome divergence was on average 582 +/- 112 MYA. These results were found to be robust to specification of the model of rate change. The clock assumption thus had a dramatic effect on date estimation. However, our results appeared sensitive to the prior model of cladogenesis, although the oldest estimates (791 +/- 246 MYA) were obtained under a suboptimal model. Bayes posterior estimates of evolutionary rates indicated at least one major burst of molecular evolution at the end of the Precambrian when protostomes and deuterostomes diverged. We stress the importance of assumptions about rates on date estimation and suggest that the large discrepancies between the molecular and fossil dates of metazoan divergences might partly be due to biases in molecular date estimation.", "keyphrases": ["precambrian", "metazoa", "divergence"]}
{"id": "paleo.003492", "title": "Recovery of benthic marine communities from the end\u2010Permian mass extinction at the low latitudes of eastern Panthalassa", "abstract": "Based on the quantitative community analysis using species\u2010level identifications, we track the restoration of benthic ecosystems after the end\u2010Permian mass extinction throughout the Lower Triassic of the western USA. New data on the palaeoecology of the Thaynes Group and Sinbad Formation are provided, which fill a gap between the recently studied palaeoecology of the Griesbachian\u2013Dienerian Dinwoody Formation and the Spathian Virgin Formation. In the Sinbad Formation and Thaynes Group, 17 species (12 genera) of bivalves, 7 species and genera of gastropods and 2 species and genera of brachiopods are recognized. The new bivalve genus Confusionella (Pteriidae) is described. A comprehensive review of the whole Lower Triassic succession of benthic ecosystems of the western USA indicates that mid\u2010 and inner shelf environments show incipient recovery signals around the Griesbachian\u2013Dienerian transition, during the Smithian and, most profound, during the early Spathian. Ecological data from youngest strata of the Dinwoody Formation as well as stratigraphic ranges of species suggest that the late Dienerian was likely a time interval of environmental stress for benthic ecosystems. Despite some evidence for short\u2010term environmental disturbances (e.g. shift of dominant taxa, transient drop in alpha\u2010diversity) during the Smithian\u2013Spathian transition, benthic ecosystems did not show any notable taxonomic turnover at that time, in contrast to the major crisis that affected ammonoids and conodonts. Whereas alpha\u2010diversity of benthic communities generally increased throughout the Early Triassic, beta\u2010diversity remained low, which reflects a persistently wide environmental range of benthic species. This observation is in accordance with a recently proposed model that predicts a time lag between increasing within\u2010habitat diversity (alpha\u2010diversity) and the onset of taxonomic differentiation between habitats (beta\u2010diversity) during biotic recoveries from mass extinction events. The observation that beta\u2010diversity had not significantly increased during the Early Triassic might also provide an explanation for the comparably sluggish increase in benthic diversity during that time, which has previously been attributed to persistent environmental stress.", "keyphrases": ["end\u2010permian mass extinction", "smithian", "benthic specie"]}
{"id": "10.1073/pnas.1600489113", "title": "Tiny individuals attached to a new Silurian arthropod suggest a unique mode of brood care", "abstract": "Significance The paper reports a remarkable arthropod from the Silurian Herefordshire Lagerst\u00e4tte of England. The fossil reveals a unique association in an early Paleozoic arthropod involving tethering of 10 tiny individuals each by a single thread to the tergites so that their appearance is reminiscent of kites. The evidence suggests that these are juveniles and that the specimen records a unique brooding strategy. This is part of a diversity of complex brooding behaviors in early arthropods heralding the variety that occurs today. The possibility that the small individuals represent a different arthropod, possibly parasitic, which colonized the larger individual, seems less likely. The \u223c430-My-old Herefordshire, United Kingdom, Lagerst\u00e4tte has yielded a diversity of remarkably preserved invertebrates, many of which provide fundamental insights into the evolutionary history and ecology of particular taxa. Here we report a new arthropod with 10 tiny arthropods tethered to its tergites by long individual threads. The head of the host, which is covered by a shield that projects anteriorly, bears a long stout uniramous antenna and a chelate limb followed by two biramous appendages. The trunk comprises 11 segments, all bearing limbs and covered by tergites with long slender lateral spines. A short telson bears long parallel cerci. Our phylogenetic analysis resolves the new arthropod as a stem-group mandibulate. The evidence suggests that the tethered individuals are juveniles and the association represents a complex brooding behavior. Alternative possibilities\u2014that the tethered individuals represent a different epizoic or parasitic arthropod\u2014appear less likely.", "keyphrases": ["arthropod", "brood care", "juvenile", "mandibulate", "tiny individual"]}
{"id": "paleo.008357", "title": "Diversity dynamics and evolutionary patterns of Devonian Bryozoa", "abstract": "Bryozoan diversity during the Devonian period displays a persistent rise from the Pragian to the early Givetian, significantly dropping in the late Givetian in the wake of the Taghanic Event. In contrast, two other important events during the Devonian, the Frasne/Famenne Event and the Hangenberg Event at the Devonian/Carboniferous boundary, were less significant and resulted mainly in shifts in faunal composition. Diversity dynamics of Devonian Bryozoa was apparently controlled by extrinsic and intrinsic factors. Global palaeogeographic settings influenced faunal provincialism to which bryozoans seem to be sensitive. Sealevel fluctuations and subsequent changes in suitability of habitats influenced biodiversification processes in bryozoans. Intrinsically, bryozoans show some patterns consistent with diffuse co-evolution with potential predators and, possibly, prey. Observed trends in the morphological evolution of Devonian bryozoans include some obvious anti-predator adaptations (protective structures, strengthened skeletal walls). Moreover, Devonian bryozoans often developed various internal modifications, which apparently influenced the activity of polypides. This pattern is regarded here as apparent improvement of feeding, possibly as a response to diminishing food in the course of the mid-Palaeozoic Phytoplankton Blackout.", "keyphrases": ["devonian bryozoa", "diversity dynamic", "shallow-water habitat", "palaeoenvironmental setting", "echinoderm"]}
{"id": "10.1206/3828.1", "title": "New Ctenodactyloid Rodents from the Erlian Basin, Nei Mongol, China, and the Phylogenetic Relationships of Eocene Asian Ctenodactyloids", "abstract": "ABSTRACT During the last decade, numerous ctenodactyloid rodent fossils have been systematically collected from at least six horizons of the strata that are distributed from the upper part of the Nomogen Formation to the lower part of the Irdin Manha Formation in the Huheboerhe-Nuhetingboerhe area of the Erlian Basin, Nei Mongol (Inner Mongolia). The ages of these fossiliferous horizons range from the Earliest Eocene to the Middle Eocene. These fossils represent the best-known ctenodactyloid assemblages with a high species diversity and reliable stratigraphic and chronological constraints from one locality in central Asia. The fossils show a relatively continuous record of ctenodactyloids and the earliest radiation of rodents in central Asia beginning from the earliest Eocene. These data are important for biostratigraphic correlation of the Paleogene in central Asia and for understanding the taxonomy of Asian ctenodactyloids and the earliest diversity and evolution of rodents. Among the new fossils, we recognized 10 species that belong to six genera and three morphotypes. Of these taxa, three new genera and species, Chenomys orientalis, gen. et sp. nov., Simplicimys bellus, gen. et sp. nov., and Yongshengomys extensus, gen. et sp. nov., are described. In addition, three new species of Tamquammys, T. robustus, sp. nov., T. longus, sp. nov., and T. fractus, sp. nov., and one new species of Yuomys, Y. huheboerhensis, sp. nov., are also named. With these new materials, we are able to briefly review some existing problems in the taxonomy of early ctenodactyloids, which has remained a difficult task in the study of this Asian rodent group. In light of the new material and taxonomic review, we conducted phylogenetic analyses of ctenodactyloids using a data matrix that contains 38 taxa and 81 characters. Our analysis shows that Chenomys, Tamquammys, and Simplicimys are placed at the base of the clade that contains the extant Ctenodactylus. Yongshengomys is the only taxon that is deeply placed within the clade containing the extant Ctenodactylus and clustered with Chuankueimys and Tsinlingomys. Our analysis supports Gobiomyidae and Ctenodactylidae as monophyletic groups, respectively, but shows that other families and subfamilies traditionally recognized, such as Cocomyinae, Advenimurinae, Tamquammyidae, Yuomyidae, and Chapattimyidae, are probably paraphyletic.", "keyphrases": ["erlian basin", "asian ctenodactyloid", "paleogene"]}
{"id": "10.1111/j.1096-3642.2008.00439.x", "title": "Neoselachians (Chondrichthyes, Elasmobranchii) from the Lower and lower Upper Cretaceous of north-eastern Spain", "abstract": "Extensive sampling of several Barremian and Albian\u2013Cenomanian levels across the Aguilon, Oliete and Aliaga subbasins of the Iberian Basin, north-east Spain, yielded abundant material of new or so far poorly known neoselachians. The faunas consist of 16 different species, five of which represent new species and two new genera: Cantioscyllium brachyplicatum sp. nov., Platypterix venustulus gen. et sp. nov., Ptychotrygon pustulata sp. nov., Ptychotrygon striata sp. nov. and Iberotrygon plagiolophus gen. et sp. nov. In addition, teeth of Heterodontus cf. H. carerens, Lamniformes indet., Pteroscyllium sp., Scyliorhinidae indet., Rhinobatos sp., Spathobatis sp., Belemnobatis sp., Ptychotrygon geyeri, Ptychotrygon sp. and Celtipristis herreroi are described. The new family Ptychotrygonidae is defined. The localities comprise palaeoenvironments ranging from lacustrine and shallow lake to open marine settings. Neoselachians are almost completely absent from continental settings in the Barremian, as a result of prevailing freshwater conditions, but became more abundant in marine strata. The Albian\u2013Cenomanian selachian assemblage is the most profuse and diverse of the three assemblages studied. It is dominated by small, benthic and near-coastal taxa, for instance Cantioscyllium and Ptychotrygon, and contains several new species, including an endemic batoid, Iberotrygon plagiolophus gen. et sp. nov.\u00a0\u00a9 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 155, 316\u2013347.", "keyphrases": ["selachian assemblage", "iberian chondricthyan", "extensive fossil record", "other cretaceous sediment"]}
{"id": "10.1073/pnas.0511296103", "title": "Rapid Asia-Europe-North America geographic dispersal of earliest Eocene primate Teilhardina during the Paleocene-Eocene Thermal Maximum.", "abstract": "True primates appeared suddenly on all three northern continents during the 100,000-yr-duration Paleocene-Eocene Thermal Maximum at the beginning of the Eocene, approximately 55.5 mya. The simultaneous or nearly simultaneous appearance of euprimates on northern continents has been difficult to understand because the source area, immediate ancestors, and dispersal routes were all unknown. Now, omomyid haplorhine Teilhardina is known on all three continents in association with the carbon isotope excursion marking the Paleocene-Eocene Thermal Maximum. Relative position within the carbon isotope excursion indicates that Asian Teilhardina asiatica is oldest, European Teilhardina belgica is younger, and North American Teilhardina brandti and Teilhardina americana are, successively, youngest. Analysis of morphological characteristics of all four species supports an Asian origin and a westward Asia-to-Europe-to-North America dispersal for Teilhardina. High-resolution isotope stratigraphy indicates that this dispersal happened in an interval of approximately 25,000 yr. Rapid geographic dispersal and morphological character evolution in Teilhardina reported here are consistent with rates observed in other contexts.", "keyphrases": ["geographic dispersal", "primate", "paleocene-eocene thermal maximum", "north america"]}
{"id": "paleo.004106", "title": "Molecular fossils within bitumens and kerogens from the\u2009~\u20091 Ga Lakhanda Lagerst\u00e4tte (Siberia, Russia) and their significance for understanding early eukaryote evolution", "abstract": "The emergence and diversification of eukaryotes during the Proterozoic is one of the most fundamental evolutionary developments in Earth's history. The ca. 1-billion-year-old Lakhanda Lagerst\u00e4tte (Siberia, Russia) contains a wealth of eukaryotic body fossils and offers an important glimpse into their ecosystem. Seeking to complement the paleontological record of this remarkable lagerst\u00e4tte, we here explored information encoded within sedimentary organic matter (total organic carbon = 0.01-1.27 wt.%). Major emphasis was placed on sedimentary hydrocarbons preserved within bitumens and kerogens, including molecular fossils (or organic biomarkers) that are specific to bacteria and eukaryotes (i.e. hopanes and regular steranes, respectively). Programmed pyrolysis and molecular organic geochemistry suggest that the organic matter in the analyzed samples is about peak oil window maturity and thus sufficiently well preserved for detailed molecular fossil studies that include hopanes and steranes. Together with petrographic evidence as well as compositional similarities of the bitumens and corresponding kerogens, the consistency of different independent maturity parameters establishes that sedimentary hydrocarbons are indigenous and syngenetic to the host rock. The possible presence of trace amounts of hopanes and absence of steranes in samples that are sufficiently well preserved to retain both types of compounds evidences an environment dominated by anaerobic bacteria with no or very little inputs by eukaryotes. In concert with the paleontological record of the Lakhanda Lagerst\u00e4tte, our study adds to the view that eukaryotes were present but not significant in Mesoproterozoic ecosystems.", "keyphrases": ["bitumen", "eukaryote", "mesoproterozoic ecosystem", "molecular fossil"]}
{"id": "10.1126/science.1143325", "title": "A Late Triassic Dinosauromorph Assemblage from New Mexico and the Rise of Dinosaurs", "abstract": "It has generally been thought that the first dinosaurs quickly replaced more archaic Late Triassic faunas, either by outcompeting them or when the more archaic faunas suddenly became extinct. Fossils from the Hayden Quarry, in the Upper Triassic Chinle Formation of New Mexico, and an analysis of other regional Upper Triassic assemblages instead imply that the transition was gradual. Some dinosaur relatives preserved in this Chinle assemblage belong to groups previously known only from the Middle and lowermost Upper Triassic outside North America. Thus, the transition may have extended for 15 to 20 million years and was probably diachronous at different paleolatitudes.", "keyphrases": ["late triassic", "new mexico", "archosaur", "terrestrial ecological niche", "ecological dominance"]}
{"id": "10.1146/annurev-earth-040610-133349", "title": "Conservation Paleobiology: Leveraging Knowledge of the Past to Inform Conservation and Restoration", "abstract": "Humans now play a major role in altering Earth and its biota. Finding ways to ameliorate human impacts on biodiversity and to sustain and restore the ecosystem services on which we depend is a grand scientific and societal challenge. Conservation paleobiology is an emerging discipline that uses geohistorical data to meet these challenges by developing and testing models of how biota respond to environmental stressors. Here we (a) describe how the discipline has already provided insights about biotic responses to key environmental stressors, (b) outline research aimed at disentangling the effects of multiple stressors, (c) provide examples of deliverables for managers and policy makers, and (d) identify methodological advances in geohistorical analysis that will foster the next major breakthroughs in conservation outcomes. We highlight cases for which exclusive reliance on observations of living biota may lead researchers to erroneous conclusions about the nature and magnitude of biotic change, vulnerabili...", "keyphrases": ["past", "biodiversity", "biotic response", "conservation paleobiology", "degradation"]}
{"id": "paleo.009689", "title": "Radiation of Extant Cetaceans Driven by Restructuring of the Oceans", "abstract": "Abstract The remarkable fossil record of whales and dolphins (Cetacea) has made them an exemplar of macroevolution. Although their overall adaptive transition from terrestrial to fully aquatic organisms is well known, this is not true for the radiation of modern whales. Here, we explore the diversification of extant cetaceans by constructing a robust molecular phylogeny that includes 87 of 89 extant species. The phylogeny and divergence times are derived from nuclear and mitochondrial markers, calibrated with fossils. We find that the toothed whales are monophyletic, suggesting that echolocation evolved only once early in that lineage some 36\u201334 Ma. The rorqual family (Balaenopteridae) is restored with the exclusion of the gray whale, suggesting that gulp feeding evolved 18\u201316 Ma. Delphinida, comprising all living dolphins and porpoises other than the Ganges/Indus dolphins, originated about 26 Ma; it contains the taxonomically rich delphinids, which began diversifying less than 11 Ma. We tested 2 hypothesized drivers of the extant cetacean radiation by assessing the tempo of lineage accumulation through time. We find no support for a rapid burst of speciation early in the history of extant whales, contrasting with expectations of an adaptive radiation model. However, we do find support for increased diversification rates during periods of pronounced physical restructuring of the oceans. The results imply that paleogeographic and paleoceanographic changes, such as closure of major seaways, have influenced the dynamics of radiation in extant cetaceans.", "keyphrases": ["restructuring", "cetacea", "diversification", "extant specie"]}
{"id": "paleo.005667", "title": "The Good, the Bad, and the Ugly: The Influence of Skull Reconstructions and Intraspecific Variability in Studies of Cranial Morphometrics in Theropods and Basal Saurischians", "abstract": "Several studies investigating macroevolutionary skull shape variation in fossil reptiles were published recently, often using skull reconstructions taken from the scientific literature. However, this approach could be potentially problematic, because skull reconstructions might differ notably due to incompleteness and/or deformation of the material. Furthermore, the influence of intraspecific variation has usually not been explored in these studies. Both points could influence the results of morphometric analyses by affecting the relative position of species to each other within the morphospace. The aim of the current study is to investigate the variation in morphometric data between skull reconstructions based on the same specimen, and to compare the results to shape variation occurring in skull reconstructions based on different specimens of the same species (intraspecific variation) and skulls of closely related species (intraspecific variation). Based on the current results, shape variation of different skull reconstructions based on the same specimen seems to have generally little influence on the results of a geometric morphometric analysis, although it cannot be excluded that some erroneous reconstructions of poorly preserved specimens might cause problems occasionally. In contrast, for different specimens of the same species the variation is generally higher than between different reconstructions based on the same specimen. For closely related species, at least with similar ecological preferences in respect to the dietary spectrum, the degree of interspecific variation can overlap with that of intraspecific variation, most probably due to similar biomechanical constraints.", "keyphrases": ["influence", "skull reconstruction", "deformation"]}
{"id": "10.1666/13-090", "title": "A review of paleontological finite element models and their validity", "abstract": "Abstract Finite element analysis (FEA) is a powerful quantitative tool that models mechanical performance in virtual reconstructions of complex structures, such as animal skeletons. The unique potential of FEA to elucidate the function, performance, and ecological roles of extinct taxa is an alluring prospect to paleontologists, and the technique has gained significant attention over recent years. However, as with all modeling approaches, FE models are highly sensitive to the information that is used to construct them. Given the imperfect quality of the fossil record, paleontologists are unlikely to ever know precisely which numbers to feed into their models, and it is therefore imperative that we understand how variation in FEA inputs directly affects FEA results. This is achieved through sensitivity and validation studies, which assess how inputs influence outputs, and compare these outputs to experimental data obtained from extant species. Although these studies are restricted largely to primates at present, they highlight both the power and the limitations of FEA. Reassuringly, FE models seem capable of reliably reproducing patterns of stresses and strains even with limited input data, but the magnitudes of these outputs are often in error. Paleontologists are therefore cautioned not to over-interpret their results. Crucially, validations show that without knowledge of skeletal material properties, which are unknowable from fossilized tissues, absolute performance values such as breaking stresses cannot be accurately determined. The true power of paleontological FEA therefore lies in the ability to manipulate virtual representations of morphology, to make relative comparisons between models, and to quantitatively assess how evolutionary changes of shape result in functional adaptations.", "keyphrases": ["finite element analysis", "fea", "mechanical performance", "complex structure", "stress"]}
{"id": "paleo.000182", "title": "Olson's Gap or Olson's Extinction? A Bayesian tip-dating approach to resolving stratigraphic uncertainty", "abstract": "Adaptive radiations and mass extinctions are of critical importance in structuring terrestrial ecosystems. However, the causes and progress of these transitions often remain controversial, in part because of debates surrounding the completeness of the fossil record and biostratigraphy of the relevant fossil-bearing formations. The early\u2013middle Permian, when a substantial faunal turnover in tetrapods coincided with a restructuring of the trophic structure of ecosystems, is such a time. Some have suggested the transition is obscured by a gap in the tetrapod fossil record (Olson's Gap), while others suggest a correlation between North American and Russian tetrapod-bearing formations allows the interval to be documented in detail. The latter biostratigraphic scheme has been used to support a mass extinction at this time (Olson's Extinction). Bayesian tip-dating methods used frequently in phylogenetics are employed to resolve this debate. Bayes factors are used to compare the results of analyses incorporating tip age priors based on different stratigraphic hypotheses, to show which stratigraphic scheme best fits the morphological data and phylogeny. Olson's Gap is rejected, and the veracity of Olson's Extinction is given further support. Tip-dating approaches have great potential to resolve debates surrounding the stratigraphic ages of critical formations where appropriate morphological data is available.", "keyphrases": ["gap", "tetrapod", "olson"]}
{"id": "10.1080/03115518.2020.1781257", "title": "New occurrence of the Guanshan Lagerst\u00e4tte (Cambrian Series 2, Stage 4) in the Kunming area, Yunnan, southwest China, with records of new taxa", "abstract": "Abstract As a classic Burgess-Shale-Type Konservat-Lagerst\u00e4tte, the Guanshan biota is well known for its abundant soft-bodied fossils with high taxonomic diversity. Here, we report a new locality of the Guanshan biota in the Kunming area, Yunnan, South China with several new forms being first documented. In particular: a naraoiid euarthropod, the dorsal exoskeleton of which has characters of both naraoiids and Emucaris; and a discoidal animal, identified as a small eldonioid-like metazoan, which has a counterpart from the Emu Bay Shale Lagerst\u00e4tte of South Australia, and which further strengths the biogeographic connection between the early Cambrian biotas of South China and Australia. Our new discoveries not only expand the palaeogeographic distribution of the Guanshan biota, but also reveal that its biodiversity is much higher than previously thought, and can be justifiably regarded as a community successor to the Chengjiang biota. Jun Zhao [zhaojunpaleo@126.com], Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, Yunnan, 650091, China; Yunnan Key Laboratory of International Rivers and Transboundary Eco-Security, Yunnan University, Kunming 650091, China; MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Institute of Palaeontology, Yunnan University, Kunming, Yunnan, 650091, China; Yujing Li [yujingli@ynu.edu.cn], Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, Yunnan, 650091, China; MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Institute of Palaeontology, Yunnan University, Kunming, Yunnan, 650091, China; Paul A. Selden [selden@ku.edu], Department of Geology, University of Kansas, 1457 Jayhawk Boulevard, Lawrence, KS 66045, USA; Natural History Museum, Cromwell Road, London SW7 5BD, UK; Peiyun Cong [cong@ynu.edu.cn], Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, Yunnan, 650091, China; MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Institute of Palaeontology, Yunnan University, Kunming, Yunnan, 650091, China.", "keyphrases": ["kunming area", "china", "guanshan biota"]}
{"id": "10.1080/02724634.1999.10011179", "title": "Ontogenetic histology of Apatosaurus (Dinosauria: Sauropoda): New insights on growth rates and longevity", "abstract": "ABSTRACT The bone microstructure of an ontogenetic series of Apatosaurus radii, ulnae, and scapulae suggests that Apatosaurus underwent three distinct osteogenic phases. Primary laminar to plexiform fibro-lamellar bone tissue, devoid of lines of arrested growth (LAG), occurs in individuals up to 91% adult size. LAGs and longitudinally vascularized lamellar tissue are deposited for the first time in the external cortices of sub-adult individuals. Slow growth and additional deposition of accretionary lamellar bone occurs in adulthood, and indicates attainment of maximum size in Apatosaurus. All scapulae examined show cyclicity in vascularity indicative of regular variation in speeds of osteogenesis. In contrast, Apatosaurus radii and ulnae show consistent bone depositional rates throughout ontogeny. Despite inter-element variability, all Apatosaurus bones sampled corroborate the hypothesis of sustained rapid growth rates for most of ontogeny, followed by gradual decline with attainment of maximum size. Esti...", "keyphrases": ["apatosaurus", "growth rate", "ontogenetic series", "tissue"]}
{"id": "paleo.011358", "title": "Respiratory Evolution Facilitated the Origin of Pterosaur Flight and Aerial Gigantism", "abstract": "Pterosaurs, enigmatic extinct Mesozoic reptiles, were the first vertebrates to achieve true flapping flight. Various lines of evidence provide strong support for highly efficient wing design, control, and flight capabilities. However, little is known of the pulmonary system that powered flight in pterosaurs. We investigated the structure and function of the pterosaurian breathing apparatus through a broad scale comparative study of respiratory structure and function in living and extinct archosaurs, using computer-assisted tomographic (CT) scanning of pterosaur and bird skeletal remains, cineradiographic (X-ray film) studies of the skeletal breathing pump in extant birds and alligators, and study of skeletal structure in historic fossil specimens. In this report we present various lines of skeletal evidence that indicate that pterosaurs had a highly effective flow-through respiratory system, capable of sustaining powered flight, predating the appearance of an analogous breathing system in birds by approximately seventy million years. Convergent evolution of gigantism in several Cretaceous pterosaur lineages was made possible through body density reduction by expansion of the pulmonary air sac system throughout the trunk and the distal limb girdle skeleton, highlighting the importance of respiratory adaptations in pterosaur evolution, and the dramatic effect of the release of physical constraints on morphological diversification and evolutionary radiation.", "keyphrases": ["pterosaur", "extinct archosaur", "respiratory system", "air sac system", "pterodactyloidea"]}
{"id": "10.1017/pab.2020.28", "title": "Verifiability of genus-level classification under quantification and parsimony theories: a case study of follicucullid radiolarians", "abstract": "Abstract. The classical taxonomy of fossil invertebrates is based on subjective judgments of morphology, which can cause confusion, because there are no codified standards for the classification of genera. Here, we explore the validity of the genus taxonomy of 75 species and morphospecies of the Follicucullidae, a late Paleozoic family of radiolarians, using a new method, Hayashi's quantification theory II (HQT-II), a general multivariate statistical method for categorical datasets relevant to discriminant analysis. We identify a scheme of 10 genera rather than the currently accepted 3 genera (Follicucullus, Ishigaconus, and Parafollicucullus). As HQT-II cannot incorporate stratigraphic data, a phylogenetic tree of Follicucullidae was reconstructed for 38 species using maximum parsimony. Six lineages emerged, roughly in concordance with the results of HQT-II. Combined with parsimony ancestral state reconstruction, the ancestral group of this family is Haplodiacanthus. Five other groups were discriminated, the Parafollicucullus, Curvalbaillella, Pseudoalbaillella, Longtanella, and Follicucullus\u2013Cariver lineages. The morphological evolution of these lineages comprises a minimum essential list of eight states of four traits. HQT-II is a novel discriminant analytical multivariate method that may be of value in other taxonomic problems of paleobiology.", "keyphrases": ["parsimony theory", "follicucullidae", "scheme", "longtanella"]}
{"id": "10.1126/science.aac4315", "title": "Abrupt warming events drove Late Pleistocene Holarctic megafaunal turnover", "abstract": "Climate killed off the megafauna The causes of the Pleistocene extinctions of large numbers of megafaunal species in the Northern Hemisphere remain unclear. A range of evidence points to human hunting, climate change, or a combination of both. Using ancient DNA and detailed paleoclimate data, Cooper et al. report a close relationship between Pleistocene megafaunal extinction events and rapid warming events at the start of interstadial periods. Their analysis strengthens the case for climate change as the key driver of megafaunal extinctions, with human impacts playing a secondary role. Science, this issue p. 602 Pleistocene megafaunal extinctions in the Northern Hemisphere were driven by rapid phases of climate warming. The mechanisms of Late Pleistocene megafauna extinctions remain fiercely contested, with human impact or climate change cited as principal drivers. We compared ancient DNA and radiocarbon data from 31 detailed time series of regional megafaunal extinctions and replacements over the past 56,000 years with standard and new combined records of Northern Hemisphere climate in the Late Pleistocene. Unexpectedly, rapid climate changes associated with interstadial warming events are strongly associated with the regional replacement or extinction of major genetic clades or species of megafauna. The presence of many cryptic biotic transitions before the Pleistocene/Holocene boundary revealed by ancient DNA confirms the importance of climate change in megafaunal population extinctions and suggests that metapopulation structures necessary to survive such repeated and rapid climatic shifts were susceptible to human impacts.", "keyphrases": ["warming event", "northern hemisphere", "biotic transition"]}
{"id": "paleo.004956", "title": "Osteology and relationships of Thaiichthys nov. gen.: a Ginglymodi from the Late Jurassic \u2013 Early Cretaceous of Thailand", "abstract": "Abstract:\u2002 The osteology of Thaiichthys buddhabutrensis, nov. gen., from the Late Jurassic \u2013 Early Cretaceous of Thailand is described on the basis of a collection of well\u2010preserved specimens. The mode of preservation of the material allows describing the external anatomy, as well as some elements of the internal anatomy (braincase, elements of the vertebral column). Most of the cranial and postcranial skeleton shows a rather conservative anatomy for \u2018semionotiformes\u2019, but the jaw apparatus displays specializations. Variations observed in the ossification pattern of the skull roof and of the cheek, in the morphology of the median dorsal scales and in fin rays\u2019 count indicate that caution should be applied when these characters are used in diagnoses and in phylogenetic analyses. A phylogenetic analysis including a set of gars, of \u2018semionotiformes\u2019, of Macrosemiiformes and of Halecomorphi shows the following features: (1) the monophyly of Holostei; (2) sister\u2010pair relationships between Tlayuamichin/Semiolepis, Isanichthys/\u2019Lepidotes\u2019 latifrons and Araripelepidotes/Pliodetes; (3) the latter pair, together with Thaiichthys and possibly \u2018Lepidotes\u2019 mantelli, are resolved as stem Lepisosteiformes; and (4) the \u2018semionotiformes\u2019 (a group gathering species of Semionotus and Lepidotes) do not form a clade.", "keyphrases": ["late jurassic", "macrosemiiformes", "osteology"]}
{"id": "paleo.007528", "title": "The Ontogenetic Osteohistology of Tenontosaurus tilletti", "abstract": "Tenontosaurus tilletti is an ornithopod dinosaur known from the Early Cretaceous (Aptian-Albian) Cloverly and Antlers formations of the Western United States. It is represented by a large number of specimens spanning a number of ontogenetic stages, and these specimens have been collected across a wide geographic range (from central Montana to southern Oklahoma). Here I describe the long bone histology of T. tilletti and discuss histological variation at the individual, ontogenetic and geographic levels. The ontogenetic pattern of bone histology in T. tilletti is similar to that of other dinosaurs, reflecting extremely rapid growth early in life, and sustained rapid growth through sub-adult ontogeny. But unlike other iguanodontians, this dinosaur shows an extended multi-year period of slow growth as skeletal maturity approached. Evidence of termination of growth (e.g., an external fundamental system) is observed in only the largest individuals, although other histological signals in only slightly smaller specimens suggest a substantial slowing of growth later in life. Histological differences in the amount of remodeling and the number of lines of arrested growth varied among elements within individuals, but bone histology was conservative across sampled individuals of the species, despite known paleoenvironmental differences between the Antlers and Cloverly formations. The bone histology of T. tilletti indicates a much slower growth trajectory than observed for other iguanodontians (e.g., hadrosaurids), suggesting that those taxa reached much larger sizes than Tenontosaurus in a shorter time.", "keyphrases": ["tenontosaurus tilletti", "bone histology", "ontogeny", "maturity", "line"]}
{"id": "10.1017/jpa.2016.66", "title": "Intracolony variation in colony morphology in reassembled fossil ramose stenolaemate bryozoans from the Upper Ordovician (Katian) of the Cincinnati Arch region, USA", "abstract": "Abstract. \n Clusters of associated colony fragments discovered weathering out of bedding planes in the Upper Ordovician of the Cincinnati, Ohio, region provide a rare opportunity to quantify intracolony variation in ramose stenolaemate bryozoans. Sixteen colonies were reassembled as completely as possible from 198 fragments, and the following colony-level characters were measured: colony dimensions, branch link length and diameter, and branch order. Results indicate that branch link length and diameter systematically decrease as colonies grow via branch bifurcation. Branching ratio (i.e., the number of distal first-order branches divided by the number of immediately proximal second-order branches) appears to be more genetically than environmentally controlled and to be consistent among orders of stenolaemates and perhaps across the phylum. Colonies with endozones mined out by endoskeletozoans result in broken branches as opposed to pristine growing tips. This varies stratigraphically, perhaps in response to the distribution of the boring animals. The rarity of borers and the systematic proximal increase in branch diameter in these colonies suggest the zooids in the proximal portions of the colonies were alive at the time of colony death. If the time and effort can be invested in reassembling colonies, these morphometric data can then be applied to taxonomic, phylogenetic, and paleoenvironmental studies.", "keyphrases": ["upper ordovician", "intracolony variation", "small bush-like colony", "cylindrical branch"]}
{"id": "10.5194/cp-9-423-2013", "title": "Proxy benchmarks for intercomparison of 8.2 ka simulations", "abstract": "Abstract. The Paleoclimate Modelling Intercomparison Project (PMIP3) now includes the 8.2 ka event as a test of model sensitivity to North Atlantic freshwater forcing. To provide benchmarks for intercomparison, we compiled and analyzed high-resolution records spanning this event. Two previously-described anomaly patterns that emerge are cooling around the North Atlantic and drier conditions in the Northern Hemisphere tropics. Newer to this compilation are more robustly-defined wetter conditions in the Southern Hemisphere tropics and regionally-limited warming in the Southern Hemisphere. Most anomalies around the globe lasted on the order of 100 to 150 yr. More quantitative reconstructions are now available and indicate cooling of ~ 1 \u00b0C and a ~ 20% decrease in precipitation in parts of Europe as well as spatial gradients in \u03b418O from the high to low latitudes. Unresolved questions remain about the seasonality of the climate response to freshwater forcing and the extent to which the bipolar seesaw operated in the early Holocene.", "keyphrases": ["intercomparison", "north atlantic", "cooling"]}
{"id": "10.3389/feart.2020.00098", "title": "Pictorial Atlas of Fossil and Extant Horseshoe Crabs, With Focus on Xiphosurida", "abstract": "Horseshoe crabs are an iconic group of extant chelicerates, with a stunning fossil record that extends to at least the Lower Ordovician (~480 million years ago). As such, the group has retained significant biological and palaeontological interest. The sporadic nature of descriptive and systematic research into fossil horseshoe crabs over the last two centuries has spread information on the group across more than 200 texts dating from the early nineteenth century to the present day. We present the most comprehensive pictorial atlas of horseshoe crabs to date to pool these important data together. This review highlights taxa such as Bellinurus lacoei and Limulus priscus that have never been documented with photography. Furthermore, key morphological features of the true horseshoe crab (Xiphosurida) families\u2014Austrolimulidae, Belinuridae, Limulidae, Paleolimulidae, and Rolfeiidae\u2014are described. The evolutionary history of horseshoe crabs is reviewed and the current issues facing any possible biogeographic work are presented. Four major future directions that should be adopted by horseshoe crab researchers are outlined. We conclude that this review provides the basis for innovative geographic and geometric morphometric studies needed to uncover facets of horseshoe crab evolution.", "keyphrases": ["horseshoe crab", "xiphosurida", "lower ordovician"]}
{"id": "10.1006/jhev.2001.0515", "title": "An early bone tool industry from the Middle Stone Age at Blombos Cave, South Africa: implications for the origins of modern human behaviour, symbolism and language.", "abstract": "Twenty-eight bone tools were recovered in situ from ca. 70 ka year old Middle Stone Age levels at Blombos Cave between 1992 and 2000. These tools are securely provenienced and are the largest collection to come from a single African Middle Stone Age site. Detailed analyses show that tool production methods follow a sequence of deliberate technical choices starting with blank production, the use of various shaping methods and the final finishing of the artefact to produce \"awls\" and \"projectile points\". Tool production processes in the Middle Stone Age at Blombos Cave conform to generally accepted descriptions of \"formal\" techniques of bone tool manufacture. Comparisons with similar bone tools from the Later Stone Age at Blombos Cave, other Cape sites and ethnographic collections show that although shaping methods are different, the planning and execution of bone tool manufacture in the Middle Stone Age is consistent with that in the late Holocene. The bone tool collection from Blombos Cave is remarkable because bone tools are rarely found in African Middle or Later Stone Age sites before ca. 25 ka. Scarcity of early bone tools is cited as one strand of evidence supporting models for nonmodern behaviour linked to a lack of modern technological or cognitive capacity before ca. 50 ka. Bone artefacts are a regular feature in European sites after ca. 40 ka, are closely associated with the arrival of anatomically modern humans and are a key behavioural marker of the Upper Palaeolithic \"symbolic explosion\" linked to the evolution of modern behaviour. Taken together with recent finds from Klasies River, Katanda and other African Middle Stone Age sites the Blombos Cave evidence for formal bone working, deliberate engraving on ochre, production of finely made bifacial points and sophisticated subsistence strategies is turning the tide in favour of models positing behavioural modernity in Africa at a time far earlier than previously accepted.", "keyphrases": ["bone tool", "middle stone age", "blombos cave", "behaviour", "point"]}
{"id": "10.1073/pnas.98.4.1358", "title": "Evidence of termite foraging by Swartkrans early hominids.", "abstract": "Previous studies have suggested that modified bones from the Lower Paleolithic sites of Swartkrans and Sterkfontein in South Africa represent the oldest known bone tools and that they were used by Australopithecus robustus to dig up tubers. Macroscopic and microscopic analysis of the wear patterns on the purported bone tools, pseudo bone tools produced naturally by known taphonomic processes, and experimentally used bone tools confirm the anthropic origin of the modifications. However, our analysis suggests that these tools were used to dig into termite mounds, rather than to dig for tubers. This result indicates that early hominids from southern Africa maintained a behavioral pattern involving a bone tool material culture that may have persisted for a long period and strongly supports the role of insectivory in the early hominid diet.", "keyphrases": ["swartkrans", "early hominid", "bone tool", "termite mound"]}
{"id": "10.1080/03115518.2015.1069485", "title": "New ontogenetic information on Duyunaspis duyunensis Zhang & Qian in Zhou et al., 1977 (Trilobita, Corynexochida) from the Cambrian and its possible sexual dimorphism", "abstract": "Lei, Q.P., September .2015. New ontogenetic information on Duyunaspis duyunensis Zhang & Qian in Zhou et al., 1977 (Trilobita, Corynexochida) from the Cambrian and its possible sexual dimorphism. Alcheringa 40, XXX\u2013XXX. ISSN 0311-5518. The hypostomal condition and the complete ontogenetic development of Duyunaspis duyunensis Zhang & Qian in Zhou et al., 1977 are restudied on the basis of abundant specimens from the Balang Formation (Cambrian, Qiandongian) in Zila Village, Paiwu Township, Huayuan County, Hunan Province. The relatively complete ontogenetic series (degree 0 to 9) provides new evidence that the holaspis of this species has nine rather than seven thoracic segments as proposed by McNamara et al. (2006). Comparisons between Duyunaspis duyunensis and two associated species, Arthricocephalus chauveaui and Changaspis elongata, support its placement in the Subfamily Oryctocarinae. Moreover, based on observations of a large number of specimens, the presence of an anterior indentation on the pygidial end is possibly representative of sexual dimorphism. Qianping Lei [cicelyapple@126.com], Natural Department, Changzhou Museum, Changzhou, Jiangsu Province, 213022, PR China; State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, 210008, PR China.", "keyphrases": ["duyunaspis duyunensis zhang", "corynexochida", "hunan province", "new ontogenetic information", "balangia"]}
{"id": "10.1344/105.000000344", "title": "The four phases of plant-arthropod associations in deep time", "abstract": "Vascular-plant hosts, their arthropod herbivores, and associated functional feeding groups are distributed spatiotemporally into four major herbivore expansions during the past 420 m.y. They are: (1) a Late Silurian to Late Devonian (60 m.y.) phase of myriapod and apterygote, hexapod (perhaps pterygote) herbivores on several clades of primitive vascular-plant hosts and a prototaxalean fungus; (2) a Late Mississippian to end-Permian (85 m.y.) phase of mites and apterygote and basal pterygote herbivores on pteridophyte and basal gymnospermous plant hosts; (3) a Middle Triassic to Recent (245 m.y.) phase of mites, orthopteroids (in the broadest sense) and hemipteroid and basal holometabolan herbivores on pteridophyte and gymnospermous plant hosts; and (4) a mid Early Cretaceous to Recent (115 m.y.) phase of modern-aspect orthopteroids and derived hemipteroid and holometabolous herbivores on angiospermous plant hosts. These host-plant and herbivore associations are mediated by seven functional feeding groups: a) external foliage feeding, b) piercing-and-sucking, c) boring (Phase 1 origins); d) galling, e) seed predation, f) nonfeeding oviposition (Phase 2 origins); and leaf mining (early Phase 3 origin). Within about 20 m.y. of each herbivore expansion, there is a biota that expresses the nearly full spectrum of later plant-arthropod associations. These four associational phases may be linked to the paleoclimatologic variables of greenhouse/icehouse cycles and atmospheric O2 and CO2 levels by uncertain causes, although some relationship probably is present. The 7 functional feeding groups persist through most of the sampled interval but harbor host-plants and arthropod herbivores that are spatiotemporally ephemeral. Poor understanding of associations in Phases 1 to 3 is attributed to disproportionate focus on the angiosperm and holometabolan insect associations of Phase 4.", "keyphrases": ["plant-arthropod association", "functional feeding group", "external foliage feeding", "piercing-and-sucking"]}
{"id": "paleo.001772", "title": "Body mass estimates of an exceptionally complete Stegosaurus (Ornithischia: Thyreophora): comparing volumetric and linear bivariate mass estimation methods", "abstract": "Body mass is a key biological variable, but difficult to assess from fossils. Various techniques exist for estimating body mass from skeletal parameters, but few studies have compared outputs from different methods. Here, we apply several mass estimation methods to an exceptionally complete skeleton of the dinosaur Stegosaurus. Applying a volumetric convex-hulling technique to a digital model of Stegosaurus, we estimate a mass of 1560 kg (95% prediction interval 1082\u20132256 kg) for this individual. By contrast, bivariate equations based on limb dimensions predict values between 2355 and 3751 kg and require implausible amounts of soft tissue and/or high body densities. When corrected for ontogenetic scaling, however, volumetric and linear equations are brought into close agreement. Our results raise concerns regarding the application of predictive equations to extinct taxa with no living analogues in terms of overall morphology and highlight the sensitivity of bivariate predictive equations to the ontogenetic status of the specimen. We emphasize the significance of rare, complete fossil skeletons in validating widely applied mass estimation equations based on incomplete skeletal material and stress the importance of accurately determining specimen age prior to further analyses.", "keyphrases": ["stegosaurus", "volumetric", "extinct taxa", "ontogenetic status", "body mass"]}
{"id": "paleo.011256", "title": "A Subadult Specimen of Rubeosaurus ovatus (Dinosauria: Ceratopsidae), with Observations on Other Ceratopsids from the Two Medicine Formation", "abstract": "Background Centrosaurine ceratopsids are well known from the middle Campanian Upper Two Medicine Formation of Montana. Four taxa have been named: Brachyceratops montanensis, Rubeosaurus ovatus, Einiosaurus procurvicornis, and Achelousaurus horneri. Rubeosaurus has been historically the most enigmatic of these taxa; only two specimens, the holotype caudal parietal bar and a referred incomplete skull, have been assigned to Rubeosaurus. Methodology/Principal Findings A revised interpretation of the parietal processes of USNM 14765, the partial skeleton of a subadult centrosaurine formerly referred to Brachyceratops, indicates that it shares a P5 spike with the holotype of Rubeosaurus ovatus and should therefore be referred to that taxon. Brachyceratops is considered a nomen dubium. Conclusions/Significance USNM 14765 provides additional anatomical information for Rubeosaurus ovatus. These new data are incorporated into a recent phylogenetic analysis of centrosaurine relationships; Rubeosaurus appears as the sister taxon of a clade composed of Einiosaurus, Achelousaurus, and Pachyrhinosaurus.", "keyphrases": ["rubeosaurus ovatus", "centrosaurine", "einiosaurus"]}
{"id": "paleo.002269", "title": "Experimental analysis of soft\u2010tissue fossilization: opening the black box", "abstract": "Taphonomic experiments provide important insights into fossils that preserve the remains of decay\u2010prone soft tissues, tissues that are usually degraded and lost prior to fossilization. These fossils are among the most scientifically valuable evidence of ancient life on Earth, giving us a view into the past that is much less biased and incomplete than the picture provided by skeletal remains alone. Although the value of taphonomic experiments is beyond doubt, a lack of clarity regarding their purpose and limitations, and ambiguity in the use of terminology, are hampering progress. Here we distinguish between processes that promote information retention and those that promote information loss, in order to clarify the distinction between fossilization and preservation. Recognizing distinct processes of decay, mineralization and maturation, the sequence in which they act, and the potential for interactions, has important consequences for analysis of fossils, and for the design of taphonomic experiments. The purpose of well\u2010designed taphonomic experiments is generally to understand decay, maturation and preservation individually, thus limiting the number of variables involved. Much work remains to be done, but these methodologically reductionist foundations will allow researchers to build towards more complex taphonomic experiments and a more holistic understanding and analysis of the interactions between decay, maturation and preservation in the fossilization of non\u2010biomineralized remains. Our focus must remain on the key issue of understanding what exceptionally preserved fossils reveal about the history of biodiversity and evolution, rather than on debating the scope and value of an experimental approach.", "keyphrases": ["tissue", "information loss", "decay"]}
{"id": "10.1666/0094-8373-36.1.80", "title": "Origins of microfossil bonebeds: insights from the Upper Cretaceous Judith River Formation of north-central Montana", "abstract": "Abstract Microfossil bonebeds are multi-individual accumulations of disarticulated and dissociated vertebrate hardparts dominated by elements in the millimeter to centimeter size range (\u226575% of bioclasts \u22645 cm maximum dimension). Modes of accumulation are often difficult to decipher from reports in the literature, although predatory (scatological) and fluvial/hydraulic origins are typically proposed. We studied the sedimentology and taphonomy of 27 microfossil bonebeds in the Campanian Judith River Formation of Montana in order to reconstruct formative histories. Sixteen of the bonebeds examined are hosted by fine-grained facies that accumulated in low-energy aquatic settings (pond/lake microfossil bonebeds). Eleven of the bonebeds are embedded in sandstones that accumulated in ancient fluvial settings (channel-hosted microfossil bonebeds). In lieu of invoking separate pathways to accumulation based on facies distinctions, we present a model that links the accumulation of bioclasts in the two facies. We propose that vertebrate material initially accumulates to fossiliferous levels in ponds/lakes and is later reworked and redeposited as channel-hosted assemblages. This interpretation is grounded in reasonable expectations of lacustrine and fluvial depositional systems and supported by taphonomic data. Moreover, it is consistent with faunal data that indicate that channel-hosted assemblages and pond/lake assemblages are similar with regard to presence/absence and rank-order abundance of taxa. This revised model of bonebed formation has significant implications for studies of vertebrate paleoecology that hinge on analyses of faunal data recovered from vertebrate microfossil assemblages. Pond/lake microfossil bonebeds in the Judith River record are preserved in situ at the scale of the local paleoenvironment, with no indication of postmortem transport into or out of the life habitat. Moreover, they are time-averaged samples of their source communities, which increases the likelihood of capturing both ecologically abundant species and more rare or transient members of the paleocommunity. These attributes make pond/lake microfossil bonebeds excellent targets for paleoecological studies that seek to reconstruct overall community membership and structure. In contrast, channel-hosted microfossil bonebeds in the Judith River record are out of place from a paleoenvironmental perspective because they are reworked from preexisting pond/lake assemblages and redeposited in younger channel facies. However, despite a history of exhumation and redeposition, channel-hosted microfossil bonebeds are preserved in relatively close spatial proximity to original source beds. This taphonomic reconstruction is counter to the commonly held view that microfossil bonebeds are biased samples that have experienced long-distance transport and significant hydrodynamic sorting.", "keyphrases": ["microfossil bonebed", "montana", "vertebrate material"]}
{"id": "10.1029/96PA02230", "title": "The Monterey Event in the Mediterranean: A record from shelf sediments of Malta", "abstract": "Oligo-Miocene carbonate platform and shelf sediments outcropping on the Maltese Islands provide an excellent archive of the paleoceanography of the central Mediterranean. A sequence of shallow water limestones, than shelf limestones, and marls, followed again by shallow water limestones, reflects drowning of a carbonate platform, the establishment of a shelf environment and, in the late Miocene, renewed progradation and aggradation of shallow water carbonates. The sequence recording the deepening of the Maltese platform contains several phosphorite hardgrounds and phosphorite pebble beds. These phosphorites were dated with strontium isotopes. Major episodes of phosphogenesis occurred between 25 and 16 Ma, and they are coeval with those phosphorite events reported from Florida and North Carolina. A Miocene carbon isotope and oxygen isotope stratigraphy was established on planktic and benthic foraminifera and on bulk samples. A major carbon isotope excursion with an amplitude of up to +l\u2030 between 18 and 12.5 Ma can be correlated with the globally recognized Monterey carbon isotope excursion. This is the first record of this event both in shallow water sediments and in the Mediterranean. The carbon isotope excursion precedes an oxygen isotope excursion which also was recognized in deep-sea records. Major episodes of phosphogenesis and platform drowning preceded the carbon isotope excursion by up to millions of years.", "keyphrases": ["mediterranean", "shelf sediment", "maltese islands", "miocene", "phosphorite"]}
{"id": "10.1017/pab.2018.9", "title": "Convergence on dental simplification in the evolution of whales", "abstract": "Abstract. The fossil record of mammal dentition provides crucial insight into key ecological and functional transitions throughout mammalian evolutionary history. For cetaceans, both extant clades differ markedly from their stem ancestors; neither retains the differentiated dentition or the tribosphenic molars characteristic of Mammalia. We used quantitative measures of dental complexity across fossil and living cetaceans to identify a trend toward dental simplicity through the Neogene. Both extant cetacean clades depart from the ancestral mammalian condition and concurrently converge upon a reduced and simplified dentition; modern mysticetes all have become entirely edentulous (at birth), and living odontocetes possess teeth as single-rooted, conical pegs. These two parallel trends accompany major shifts in feeding strategy (i.e., filter feeding in mysticetes and echolocation in odontocetes), suggesting that these evolutionary innovations for prey acquisition are enabling factors for the loss of prey processing and subsequent convergence on dental simplification.", "keyphrases": ["dental simplification", "mysticete", "odontocete", "convergence", "tooth"]}
{"id": "10.1111/j.1475-4983.2010.00992.x", "title": "The genus Hispanomeryx (Mammalia, Ruminantia, Moschidae) and its bearing on musk deer phylogeny and systematics", "abstract": "Abstract:\u2002 We update the systematics and comparative anatomy of the genus Hispanomeryx Morales, Moy\u00e0\u2010Sol\u00e0 and Soria, 1981 through the description of a new and abundant fossil material from the middle Miocene localities of Toril\u20103, Manchones\u20101 and Manchones\u20102, Zaragoza Province, Spain. Hispanomeryx was only known by dental remains, mainly mandibles and lower teeth, and very scarce postcranial material; the fossil sample studied here includes cranial, mandibular, dental and postcranial remains, and it allows us to describe in depth, for the first time, the anatomy of the genus. We also erect the new species Hispanomeryx daamsi. The material is good and abundant enough as to include Hispanomeryx in a cladistic analysis performed to explore its phylogenetic relationships within the Pecora. This analysis includes Hispanomeryx in a monophyletic Moschidae (musk deer) composed by Micromeryx, Hispanomeryx, \u2018Moschus\u2019 grandeavus and extant Moschus, and recovers a clade composed by moschids and bovids; this is the first time that a Moschidae\u2010Bovidae sister\u2010group relationship is backed\u2010up by morphological data. A direct sister\u2010group relationship between Hispanomeryx and the Bovidae is thus rejected. Several taxa previously assigned to the \u2018Moschidae\u2019 are rejected as true moschids. Finally, the cladistic phylogenetic analysis of Hispanomeryx demonstrates its monophyly and shows a basal species, H. aragonensis Azanza, 1986 , and a clade formed by H. duriensis Morales et al., 1981 and H. daamsi sp. nov, characterized by the presence of more derived lower molars than those of H. aragonensis.", "keyphrases": ["hispanomeryx", "moschidae", "systematic", "micromeryx", "moschid"]}
{"id": "paleo.008120", "title": "Extinction of South American sparassodontans (Metatheria): environmental fluctuations or complex ecological processes?", "abstract": "Sparassodontans are a diverse but now extinct group of metatherians that were apex predators in South America during most of the Cenozoic. Studying their decline has been controversial mainly due to the scarcity of the fossil record, and different methodological approaches have led to contradictory hypotheses. In an effort to explore questions about their extinction, we developed a novel multi\u2010model statistical approach to analyse all of the currently available data at a continental scale. Using multiple regression analysis and new advances in beta diversity analysis, we used all currently available fossil data at a continental scale to test four competing hypotheses to account for the decline of sparassodontans: competition with placental carnivorans, competition with avian phorusrhacids, non\u2010competitive ecological interactions, and environmental fluctuations. Our results show that the sparassodontan extinction was a gradual process with species disappearing throughout the Cenozoic. Multiple regression analysis supported non\u2010competitive ecological interactions as the best extinction model. Native South American ungulates, African migrants (caviomorph rodents and platyrrhine primates) and didelphimorphians were the groups with the highest statistical significance. Sparassodontan beta diversity increased between South American Land Mammal Ages after the Paleocene\u2013Eocene boundary. Our results demonstrate that ecological modelling techniques illuminate aspects of extinction processes whilst mitigating the limitations of the fossil record. Our study suggests that non\u2010competitive ecological interactions could have been the main driver for sparassodontan extinction rather than, as commonly assumed, a result of competition and/or abiotic fluctuations.", "keyphrases": ["sparassodontan", "environmental fluctuation", "multiple regression analysis", "platyrrhine primate", "ecological overlap"]}
{"id": "10.1002/jmor.20242", "title": "Dental patterning in the earliest sharks: Implications for tooth evolution", "abstract": "Doliodus problematicus is the oldest known fossil shark\u2010like fish with an almost intact dentition (Emsian, Lower Devonian, c. 397Ma). We provide a detailed description of the teeth and dentition in D. problematicus, based on tomographic analysis of NBMG 10127 (New Brunswick Museum, Canada). Comparisons with modern shark dentitions suggest that Doliodus was a ram\u2010feeding predator with a dentition adapted to seizing and disabling prey. Doliodus provides several clues about the early evolution of the \u201cshark\u2010like\u201d dentition in chondrichthyans and also raises new questions about the evolution of oral teeth in jawed vertebrates. As in modern sharks, teeth in Doliodus were replaced in a linguo\u2010labial sequence within tooth families at fixed positions along the jaws (12\u201314 tooth families per jaw quadrant in NBMG 10127). Doliodus teeth were replaced much more slowly than in modern sharks. Nevertheless, its tooth formation was apparently as highly organized as in modern elasmobranchs, in which future tooth positions are indicated by synchronized expression of shh at fixed loci within the dental epithelium. Comparable dental arrays are absent in osteichthyans, placoderms, and many \u201cacanthodians\u201d; a \u201cshark\u2010like\u201d dentition, therefore, may be a synapomorphy of chondrichthyans and gnathostomes such as Ptomacanthus. The upper anterior teeth in Doliodus were not attached to the palatoquadrates, but were instead supported by the ethmoid region of the prechordal basicranium, as in some other Paleozoic taxa (e.g., Triodus, Ptomacanthus). This suggests that the chondrichthyan dental lamina was originally associated with prechordal basicranial cartilage as well as jaw cartilage, and that the modern elasmobranch condition (in which the oral dentition is confined to the jaws) is phylogenetically advanced. Thus, oral tooth development in modern elasmobranchs does not provide a complete developmental model for chondrichthyans or gnathostomes. J. Morphol. 275:586\u2013596, 2014. \u00a9 2013 Wiley Periodicals, Inc.", "keyphrases": ["shark", "tooth", "acanthodian"]}
{"id": "10.1017/S0022336000020394", "title": "Morphological variations of benthic foraminiferal tests in response to changes in ecological parameters: a review", "abstract": "Some of the relatively recent literature correlating morphological variation in benthic foraminifera with environmental parameters such as temperature, salinity, carbonate solubility, depth, nutrition, substrate, dissolved oxygen, illumination, pollution, water motion, trace elements, and rapid environmental fluctuation is reviewed. It appears some variables (most notably depth) are recorded more frequently, which may affect some conclusions. Although each variable is treated separately, it appears that almost no variables act independently on test morphologies. In reviewing the literature, it becomes clear that there are many individual trends, especially with shell ornamentation, but few broad ones, and that it is almost impossible, with exception of some of the larger reef-dwelling, symbiont-bearing foraminifera, to predict how any species will react to various parameters. The broad trends concern thinning or thickening of carbonate tests with changing carbonate availability, temperature, and salinity. It appears that many observations of morphological changes within species may not be recorded in the literature, perhaps because authors did not recognize the importance of small details that would be of importance at a later time.", "keyphrases": ["environmental parameter", "salinity", "morphological variation"]}
{"id": "10.1080/02724634.2019.1566739", "title": "A new species of Kentriodon (Cetacea, Odontoceti, Kentriodontidae) from the Miocene of Japan", "abstract": "ABSTRACT Kentriodontids are small- to medium-sized odontocetes with a wide geographic range that flourished during the Miocene. They are closely related to crown Delphinida. Seven fossil kentriodontid specimens have been recovered from the Haraichi Formation, Annaka Group (latest middle/earliest late Miocene, Serravallian/Tortonian), Gunma Prefecture, Japan. We describe and diagnose a new species of the genus Kentriodon. Kentriodon nakajimai, sp. nov., has a larger fossa for the hamular and preorbital lobes of the pterygoid sinuses, which suggests that the species was more highly adapted for diving than other Kentriodon species. Asymmetric development of left and right maxillary crests indicates asymmetric development of the facial muscles attached to the melon. If this is the case, it suggests that K. nakajimai possessed a more sophisticated echolocation system than other kentriodontids. Phylogenetic analysis suggests that K. nakajimai is most closely related to K. obscurus and the genus Kentriodon may have originated in the Pacific and then dispersed into the Atlantic several times.", "keyphrases": ["kentriodontidae", "miocene", "odontocete", "phylogenetic analysis"]}
{"id": "paleo.012725", "title": "Male mastodon landscape use changed with maturation (late Pleistocene, North America)", "abstract": "Significance Fossil remains usually reveal little about lifetime landscape use beyond place of death, but ever-growing tusks of American mastodons (Mammut americanum) record this fundamental aspect of paleobiology. Using oxygen and strontium isotopes from a serially sampled male mastodon tusk, we reconstruct changing patterns of landscape use during his life. We find clear shifts in landscape use during adolescence and following maturation to adulthood, including increased monthly movements and development of a summer-only range and mating ground. The mastodon died in his inferred summer mating ground, far from landscapes used during other seasons. Mastodons had long gestation times, and late Pleistocene populations lived in harsh, rapidly changing environments. Seasonal landscape use and migration were likely critical for maximizing mastodon reproductive success.", "keyphrases": ["landscape use", "maturation", "american mastodon", "mammut americanum", "paleobiology"]}
{"id": "10.1029/2005PA001230", "title": "Missing organic carbon in Eocene marine sediments: Is metabolism the biological feedback that maintains end-member climates?", "abstract": "[1]\u00a0Ocean chemistry is affected by pCO2 in the atmosphere by increasing the dissolution of solid calcium carbonate and elevating the dissolved inorganic carbon concentrations in seawater. Positive feedbacks between the ocean and atmosphere can maintain high atmospheric pCO2 and affect global climate. We report evidence for changes in the oceanic carbon cycle from the first high-quality organic carbon (Corg) data set of Eocene sediments beneath the equatorial Pacific upwelling region (Leg 199 of the Ocean Drilling Program). Eocene Corg mass accumulation rates (MARs) are 10 times lower than Holocene rates, even though expected Corg MARs estimated from biogenic-barium MARs (an indicator of biological production) equal or exceed modern fluxes. What happened to the missing Corg? Recent advances in ecology and biochemical kinetics show that the metabolism of nearly all animals, marine and terrestrial, is positively correlated by first principles to environmental temperatures. The approximately 10\u00b0C abyssal temperature difference from Eocene to Holocene should have radically reduced pelagic Corg burial, as we observe. We propose that higher basal metabolism and nutrient utilization/recycling rates in the Eocene water column and surface sediments precluded Corg sediment burial in the pelagic ocean. Increased rates of metabolism, nutrient utilization, and lowered Corg sedimentation caused by increased temperature may have acted as a biological feedback to maintain high atmospheric pCO2 and hothouse climates. Conversely, these same parameters would reverse sign to maintain low pCO2 when temperatures decrease, thereby maintaining \u201cicehouse\u201d conditions during cold climate regimes.", "keyphrases": ["organic carbon", "metabolism", "global climate", "pacific upwelling region", "nutrient utilization"]}
{"id": "paleo.005785", "title": "Ammonoid septal formation and suture asymmetry explored with a geographic information systems approach", "abstract": "Given the centrality of suture patterns to ammonoid systematics, it is remarkable how little we understand about the formation of septa. Various models for septal formation have been proposed, but given the spatial complexity of suture patterns, the means to test and constrain them have been lacking. Here we use Geographic Information Systems (GIS) to test models for septal formation by analyzing spatial constraints and asymmetries in several ammonoid species, including Cretaceous ammonites (the Middle Turonian acanthoceratacean Coilopoceras and the Early Cenomanian hoplitacean Neogastroplites) and Carboniferous goniatites (the dimorphoceratacean Metadimorphoceras and the goniatacean Somoholites). These analyses show that suture lines are not more strongly constrained at lobe tips than at saddles, nor are lobe tips more strongly inflected than saddles. Rather, the entire suture line is similarly constrained and shaped at both lobes and saddles, suggesting that the process controlling septal folding acts along the entire margin of the septal membrane rather than at a few specified tie points. Right and left opposing sutures from the same specimens do not match precisely. More generally, right and left suture patterns show asymmetries both in lengths and degrees of variability. These asymmetries are consistent across individuals sampled from different localities, implying that they are species-level traits, rather than pathologies or taphonomic deformations. The directed asymmetry of suture patterns may reflect soft part asymmetry in ammonoids. These results can be used to place constraints on alternative models for septal growth and function; the GIS-based method will permit further testing of such models.", "keyphrases": ["septal formation", "suture pattern", "variability", "ammonoid"]}
{"id": "10.1073/pnas.1814081116", "title": "Forage silica and water content control dental surface texture in guinea pigs and provide implications for dietary reconstruction", "abstract": "Significance Ingesta leave characteristic wear features on the tooth surface, which enable us to reconstruct the diet of extant and fossil vertebrates. However, whether dental wear is caused by internal (phytoliths) or external (mineral dust) silicate abrasives is controversially debated in paleoanthropology and biology. To assess this, we fed guinea pigs plant forages of increasing silica content (lucerne < grass < bamboo) without any external abrasives, both in fresh and dried state. Abrasiveness and enamel surface wear increased with higher forage phytolith content. Additionally, water loss altered plant material properties. Dental wear of fresh grass feeding was similar to lucerne browsing, while dried grass caused more grazer-like wear. Fresh grass grazing could be confounded with browsing, being a major pitfall for paleodietary reconstructions. Recent studies have shown that phytoliths are softer than dental enamel but still act as abrasive agents. Thus, phytolith content should be reflected in dental wear. Because native phytoliths show lower indentation hardness than phytoliths extracted by dry ashing, we propose that the hydration state of plant tissue will also affect dental abrasion. To assess this, we performed a controlled feeding experiment with 36 adult guinea pigs, fed exclusively with three different natural forages: lucerne, timothy grass, and bamboo with distinct phytolith/silica contents (lucerne < grass < bamboo). Each forage was fed in fresh or dried state for 3 weeks. We then performed 3D surface texture analysis (3DST) on the upper fourth premolar. Generally, enamel surface roughness increased with higher forage phytolith/silica content. Additionally, fresh and dry grass feeders displayed differences in wear patterns, with those of fresh grass feeders being similar to fresh and dry lucerne (phytolith-poor) feeders, supporting previous reports that \u201cfresh grass grazers\u201d show less abrasion than unspecialized grazers. Our results demonstrate that not only phytolith content but also properties such as water content can significantly affect plant abrasiveness, even to such an extent that wear patterns characteristic for dietary traits (browser\u2013grazer differences) become indistinguishable.", "keyphrases": ["water content", "phytolith", "enamel surface", "grazer"]}
{"id": "10.1029/2006PA001380", "title": "Lowering of glacial atmospheric CO2 in response to changes in oceanic circulation and marine biogeochemistry", "abstract": "[1]\u00a0We use an Earth system model of intermediate complexity, CLIMBER-2, to investigate what recent improvements in the representation of the physics and biology of the glacial ocean imply for the atmospheric concentration. The coupled atmosphere-ocean model under the glacial boundary conditions is able to reproduce the deep, salty, stagnant water mass inferred from Antarctic deep pore water data and the changing temperature of the entire deep ocean. When carbonate compensation is included in the model, we find a CO2 drawdown of 43 ppmv associated mainly with the shoaling of the Atlantic thermohaline circulation and an increased fraction of water masses of southern origin in the deep Atlantic. Fertilizing the Atlantic and Indian sectors of the Southern Ocean north of the polar front leads to a further drawdown of 37 ppmv. Other changes to the glacial carbon cycle include a decrease in the amount of carbon stored in the terrestrial biosphere (540 Pg C), which increases atmospheric CO2 by 15 ppmv, and a change in ocean salinity resulting from a drop in sea level, which elevates CO2 by another 12 ppmv. A decrease in shallow water CaCO3 deposition draws down CO2 by 12 ppmv. In total, the model is able to explain more than two thirds (65 ppmv) of the glacial to interglacial CO2 change, based only on mechanisms that are clearly documented in the proxy data. A good match between simulated and reconstructed distribution of \u03b413C changes in the deep Atlantic suggests that the model captures the mechanisms of reorganization of biogeochemistry in the Atlantic Ocean reasonably well. Additional, poorly constrained mechanisms to explain the rest of the observed drawdown include changes in the organic carbon:CaCO3 ratio of sediment rain reaching the seafloor, iron fertilization in the subantarctic Pacific Ocean, and changes in terrestrial weathering.", "keyphrases": ["atmospheric co2", "biogeochemistry", "sea level"]}
{"id": "10.1130/G23322A.1", "title": "Detrital zircon U-Pb ages provide provenance and chronostratigraphic information from Eocene synorogenic deposits in northwestern Argentina", "abstract": "Paleogene clastic sedimentary rocks in the Puna plateau of northwestern Argentina contain valuable information about the timing and location of early mountain building in the central Andes. Because these rocks generally lack tuffaceous facies, only paleontological ages have been available. We present U-Pb ages from detrital zircons in the conglomeratic Eocene Geste Formation of the central Puna plateau. The zircon ages indicate that the Geste Formation was derived from nearby high-relief ranges composed of Ordovician metasedimentary rocks. A small population of ca. 37\u201335 Ma grains also confirms the late Eocene stratigraphic age of the Geste Formation, and suggests that U-Pb detrital zircon ages may provide a new tool for determining depositional ages and provenance of widespread Paleogene deposits in the central Andes.", "keyphrases": ["northwestern argentina", "paleogene", "depositional age"]}
{"id": "paleo.001722", "title": "The Early Cambrian origin of thylacocephalan arthropods", "abstract": "Zhenghecaris shankouensis gen. et sp. nov. is one of the largest \"bivalved\" arthropods of the Lower Cambrian Maotianshan Shale fauna. Its non-mineralized carapace was dome-like, laterally compressed, armed with rostral features, and probably enclosed the entire body of the animal. Zhenghecaris was provided with elliptical stalked lateral eyes. The carapace design, external ornament and visual organs of Zhenghecaris suggest affinities with the Thylacocephala, an extinct (Lower Silurian to Upper Cretaceous) group of enigmatic arthropods whose origins remain poorly understood. The bivalved arthropods Isoxys and Tuzoia (Lower and Middle Cambrian) are two other potential thylacocephalan candidates making this group of arthropods a possible new component of Cambrian marine communities. Zhenghecaris, Isoxys, and Tuzoia are interpreted as nektonic animals that probably inhabited the lower level of the water column in shallow shelf settings at depths of perhaps 100-150 m or less. Their feeding mode either in the water column (e.g., mesozooplankton) or on the substrate (e.g., small epibenthos, detritus) is uncertain, although some of these arthropods were possibly mid-water predators (e.g., Isoxys with raptorial appendages).", "keyphrases": ["arthropod", "visual organ", "thylacocephala", "predator", "appendage"]}
{"id": "paleo.011236", "title": "Zinc isotopes in Late Pleistocene fossil teeth from a Southeast Asian cave setting preserve paleodietary information", "abstract": "Significance Dietary habits, especially meat consumption, represent a key aspect in the behavior and evolution of fossil hominin species. Here, we explore zinc (Zn) isotope ratios in tooth enamel of fossil mammals. We show discrimination between different trophic levels and demonstrate that Zn isotopes could prove useful in paleodietary studies of fossil hominin, or other mammalian species, to assess their consumption of animal versus plant resources. We also demonstrate the high preservation potential of pristine diet-related Zn isotope ratios, even under tropical conditions with poor collagen preservation, such as the studied depositional context in Southeast Asia. However, assessing the preservation of original \u03b466Zn values is required for each fossil site as diagenesis may vary across and even within taphonomic settings. Stable carbon and nitrogen isotope ratios of collagen from bone and dentin have frequently been used for dietary reconstruction, but this method is limited by protein preservation. Isotopes of the trace element zinc (Zn) in bioapatite constitute a promising proxy to infer dietary information from extant and extinct vertebrates. The 66Zn/64Zn ratio (expressed as \u03b466Zn value) shows an enrichment of the heavy isotope in mammals along each trophic step. However, preservation of diet-related \u03b466Zn values in fossil teeth has not been assessed yet. Here, we analyzed enamel of fossil teeth from the Late Pleistocene (38.4\u201313.5 ka) mammalian assemblage of the Tam Hay Marklot (THM) cave in northeastern Laos, to reconstruct the food web and assess the preservation of original \u03b466Zn values. Distinct enamel \u03b466Zn values of the fossil taxa (\u03b466Zncarnivore < \u03b466Znomnivore < \u03b466Znherbivore) according to their expected feeding habits were observed, with a trophic carnivore-herbivore spacing of +0.60\u2030 and omnivores having intermediate values. Zn and trace element concentration profiles similar to those of modern teeth also indicate minimal impact of diagenesis on the enamel. While further work is needed to explore preservation for settings with different taphonomic conditions, the diet-related \u03b466Zn values in fossil enamel from THM cave suggest an excellent long-term preservation potential, even under tropical conditions that are well known to be adverse for collagen preservation. Zinc isotopes could thus provide a new tool to assess the diet of fossil hominins and associated fauna, as well as trophic relationships in past food webs.", "keyphrases": ["late pleistocene", "trophic level", "dentin", "zinc", "fossil tooth"]}
{"id": "10.13130/2039-4942/5517", "title": "A NEW LEPIDOSAUROMORPH REPTILE FROM THE MIDDLE TRIASSIC OF THE DOLOMITES (NORTHERN ITALY)", "abstract": "A new genus and species of diapsid reptile is described. The specimen was collected from the Anisian (Middle Triassic) succession of Monte Pra della Vacca (Kuhwiesenkopf) in the Dolomites of Braies (Bolzano/Bozen, Northern Italy). Despite being incomplete, the specimen shows enough characters to allow its placement within Lepidosauriformes, close to the Middle Jurassic genus Marmoretta. The importance of this find lies in the great rarity of lepidosauriforms of Anisian age, an epoch approximating the appearance of the first members of the true Lepidosauria (rhyncocephalians and squamates). The new genus may thus add knowledge to the diversity of early lepidosaurians. Some characters of the skeleton, mainly of the forelimb, suggest a terrestrial, perhaps arboreal life style.", "keyphrases": ["middle triassic", "first lepidosauromorph reptile", "extant lizard"]}
{"id": "10.1071/IS13010", "title": "Investigating the Bivalve Tree of Life \u2013 an exemplar-based approach combining molecular and novel morphological characters", "abstract": "Abstract. To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatomical, ultrastructural and molecular sequence data for a targeted selection of exemplar bivalves spanning the phylogenetic diversity of the class. We included molecular data for 103 bivalve species (up to five markers) and also analysed a subset of taxa with four additional nuclear protein-encoding genes. Novel as well as historically employed morphological characters were explored, and we systematically disassembled widely used descriptors such as gill and stomach \u2018types\u2019. Phylogenetic analyses, conducted using parsimony direct optimisation and probabilistic methods on static alignments (maximum likelihood and Bayesian inference) of the molecular data, both alone and in combination with morphological characters, offer a robust test of bivalve relationships. A calibrated phylogeny also provided insights into the tempo of bivalve evolution. Finally, an analysis of the informativeness of morphological characters showed that sperm ultrastructure characters are among the best morphological features to diagnose bivalve clades, followed by characters of the shell, including its microstructure. Our study found support for monophyly of most broadly recognised higher bivalve taxa, although support was not uniform for Protobranchia. However, monophyly of the bivalves with protobranchiate gills was the best-supported hypothesis with incremental morphological and/or molecular sequence data. Autobranchia, Pteriomorphia, Heteroconchia, Palaeoheterodonta, Archiheterodonta, Euheterodonta, Anomalodesmata and Imparidentia new clade (\u2009=\u2009Euheterodonta excluding Anomalodesmata) were recovered across analyses, irrespective of data treatment or analytical framework. Another clade supported by our analyses but not formally recognised in the literature includes Palaeoheterodonta and Archiheterodonta, which emerged under multiple analytical conditions. The origin and diversification of each of these major clades is Cambrian or Ordovician, except for Archiheterodonta, which diverged from Palaeoheterodonta during the Cambrian, but diversified during the Mesozoic. Although the radiation of some lineages was shifted towards the Palaeozoic (Pteriomorphia, Anomalodesmata), or presented a gap between origin and diversification (Archiheterodonta, Unionida), Imparidentia showed steady diversification through the Palaeozoic and Mesozoic. Finally, a classification system with six major monophyletic lineages is proposed to comprise modern Bivalvia: Protobranchia, Pteriomorphia, Palaeoheterodonta, Archiheterodonta, Anomalodesmata and Imparidentia.", "keyphrases": ["morphological character", "bivalve lineage", "molecular sequence data", "palaeoheterodonta", "euheterodonta"]}
{"id": "10.1080/08912963.2014.895826", "title": "Paleoenvironmental reconstruction of an Albian plant community from the Ari\u00f1o bonebed layer (Iberian Chain, NE Spain)", "abstract": "The AR-1 layer, corresponding to the Escucha Formation (Lower Cretaceous) in the Santa Maria Mine of Ari\u00f1o, has supplied rich and well-preserved macrofloral and palynological assemblages showing interesting data about both taphonomic and environmental conditions. This single layer is located in the Oliete Sub-Basin from the Maestrazgo Basin in northeastern Spain, and it represents one of the most outstanding single layer fossil sites in the world. This site shows abundant and diverse fauna containing exquisitely preserved vertebrate and invertebrate fossils (dinosaur bones, turtles, crocodiles, fishes, molluscs and ostracods) and also plant remains of Albian age. The assemblage is especially significant for dinosaur phylogenetic analysis. The sedimentary environment corresponds to a freshwater swamp plain with sporadic marine inputs within a deltaic\u2013estuarine system under subtropical\u2013tropical climate.", "keyphrases": ["freshwater swamp", "charophyte", "ari\u00f1o palaeoenvironment", "marine influence"]}
{"id": "paleo.003050", "title": "ONTOGENETIC NICHE SHIFT IN THE BRACHIOPOD TEREBRATALIA TRANSVERSA: RELATIONSHIP BETWEEN THE LOSS OF ROTATION ABILITY AND ALLOMETRIC GROWTH", "abstract": "Abstract:\u2002 Many articulated brachiopods experience marked life habit variations during ontogeny because they experience their fluid environment at successively higher Reynolds numbers, and they can change the configuration of their inhalant and exhalant flows as body size increases. We show that the extant brachiopod Terebratalia transversa undergoes a substantial ontogenetic change in reorientation governed by rotation around the pedicle. T. transversa\u2032s reorientation angle (maximum ability to rotate on the pedicle) decreases during ontogeny, from 180 degrees in juveniles to 10\u201320 degrees in individuals exceeding 5\u2003mm, to complete cessation of rotation in individuals larger than 10\u2003mm. Rotation ability is substantially reduced after T. transversa achieves the adult lophophore configuration and preferred orientation with respect to ambient water currents at a length of 2.5\u20135\u2003mm. We hypothesize that the rotation angle of T. transversa is determined mainly by the position of ventral and dorsal points of attachment of dorsal pedicle muscles relative to the pedicle. T. transversa shows a close correlation between the ontogenetic change in reorientation angle and ontogeny of morphological traits that are related to points of attachment of dorsal pedicle muscles, although other morphological features can also limit rotation in the adult stage. The major morphological change in cardinalia shape and the observed reduction of rotation affect individuals 2.5\u201310\u2003mm in length. The position of ventral insertions of dorsal pedicle muscles remains constant, but contraction of dorsal pedicle muscles is functionally handicapped because dorsal insertions shift away from the valve midline, rise above the dorsal valve floor, and become limited by a wide cardinal process early in ontogeny (<5\u2003mm). The rate of increase of cardinal process width and of distance between dorsal pedicle muscle scars substantially decreases in the subadult stage (5\u201310\u2003mm), and most of the cardinalia shell traits grow nearly isometrically in the adult stage (>10\u2003mm). T. transversa attains smaller shell length in crevices than on exposed substrates. The proportion of small\u2010sized individuals and population density is lower on exposed substrates than in crevices, indicating higher juvenile mortality on substrates prone to grazing and physical disturbance. The loss of reorientation ability can be a consequence of morphological changes that strengthen substrate attachment and maximize protection against biotic or physical disturbance (1) by minimizing torques around the pedicle axis and/or (2) by shifting energy investments into attachment strength at the expense of the cost involved in reorientation.", "keyphrases": ["brachiopod terebratalia transversa", "rotation ability", "ontogeny"]}
{"id": "paleo.012696", "title": "Ancient DNA Provides New Insights into the Evolutionary History of New Zealand's Extinct Giant Eagle", "abstract": "Prior to human settlement 700 years ago New Zealand had no terrestrial mammals\u2014apart from three species of bats\u2014instead, approximately 250 avian species dominated the ecosystem. At the top of the food chain was the extinct Haast's eagle, Harpagornis moorei. H. moorei (10\u201315 kg; 2\u20133 m wingspan) was 30%\u201340% heavier than the largest extant eagle (the harpy eagle, Harpia harpyja), and hunted moa up to 15 times its weight. In a dramatic example of morphological plasticity and rapid size increase, we show that the H. moorei was very closely related to one of the world's smallest extant eagles, which is one-tenth its mass. This spectacular evolutionary change illustrates the potential speed of size alteration within lineages of vertebrates, especially in island ecosystems.", "keyphrases": ["new zealand", "world", "large extant eagle"]}
{"id": "10.1130/G24618A.1", "title": "Biogeochemical controls on photic-zone euxinia during the end-Permian mass extinction", "abstract": "Geochemical, biomarker, and isotopic evidence suggests that the end-Permian was characterized by extreme oceanic anoxia that may have led to hydrogen sulfide buildup and mass extinction. We use an earth system model to quantify the biogeochemical and physical conditions necessary for widespread oceanic euxinia and hydrogen sulfide release to the atmosphere. Greater than threefold increases in ocean nutrient content combined with nutrient-trapping ocean circulation cause surface-water H 2 S accumulation in the paleo\u2013Tethys Ocean and in areas of strong upwelling. Accounting for the presence of sulfide-oxidizing phototrophs in the model suppresses but does not prevent widespread release of H 2 S to the atmosphere. Evidence from the geologic record is consistent with modeled geochemical distributions of widespread nutrient-induced euxinia during the end-Permian, suggesting H 2 S toxicity and hypercapnia may have provided the kill mechanism for extinction.", "keyphrases": ["euxinia", "mass extinction", "ocean"]}
{"id": "paleo.004167", "title": "The glyptodont Eleutherocercus solidus from the late Neogene of north-western Argentina: morphology, chronology, and phylogeny", "abstract": "Glyptodonts (Mammalia, Xenarthra, Glyptodontidae) represent a diversified radiation of large armored herbivores, mainly related to open biomes in South America, with an extensive fossil history since the late Eocene (ca. 33 Ma) until their extinction in the latest Pleistocene\u2013earliest Holocene. During the Pliocene and Pleistocene, glyptodonts arrived in Central and North America as part of the Great American Biotic Interchange. Within glyptodont diversity, one of the most enigmatic groups (and also one of the least known) are the Doedicurinae, mainly recognized by the enormous Pleistocene Doedicurus, with some specimens reaching ca. two tons. Almost nothing is known about the Neogene evolutionary history of this lineage. Some very complete specimens of the previously scarcely known Eleutherocercus solidus, which in turn becomes the most complete Neogene Doedicurinae, are here described in detail and compared to related taxa. The materials come from the Andalhuala and Corral Quemado formations (north-western Argentina), specifically from stratigraphic levels correlated to the Messinian\u2013Piacenzian interval (latest Miocene\u2013Pliocene). The comparative study and the cladistic analysis support the hypothesis that Doedicurinae forms a well supported monophyletic group, located within a large and diversified clade mostly restricted to southern South America. Within Doedicurinae, the genus Eleutherocercus (E. antiquus + E. solidus) is the sister group of the Pleistocene Doedicurus. Unlike most of the late Neogene and Pleistocene lineages of glyptodonts, doedicurins show along its evolutionary history a latitudinal retraction since the Pleistocene, ending with the giant Doedicurus restricted to the Pampean region of Argentina, southernmost Brazil, and southern Uruguay. This hypothetic relationship between body mass and latitudinal distribution suggests that climate could have played an active role in the evolution of the subfamily.", "keyphrases": ["late neogene", "north-western argentina", "xenarthra", "glyptodont diversity", "doedicurinae"]}
{"id": "paleo.002306", "title": "Palaeoepidemiology in extinct vertebrate populations: factors influencing skeletal health in Jurassic marine reptiles", "abstract": "Palaeoepidemiological studies related to palaeoecology are rare, but have the potential to provide information regarding ecosystem-level characteristics by measuring individual health. In order to assess factors underlying the prevalence of pathologies in large marine vertebrates, we surveyed ichthyosaurs (Mesozoic marine reptiles) from the Posidonienschiefer Formation (Early Jurassic: Toarcian) of southwestern Germany. This Formation provides a relatively large sample from a geologically and geographically restricted interval, making it ideal for generating baseline data for a palaeoepidemiological survey. We examined the influence of taxon, anatomical region, body size, ontogeny and environmental change, as represented by the early Toarcian Oceanic Anoxic Event, on the prevalence of pathologies, based on a priori ideas of factors influencing population skeletal health. Our results show that the incidence of pathologies is dependent on taxon, with the small-bodied genus Stenopterygius exhibiting fewer skeletal pathologies than other genera. Within Stenopterygius, we detected more pathologies in large adults than in smaller size classes. Stratigraphic horizon, a proxy for palaeoenvironmental change, did not influence the incidence of pathologies in Stenopterygius. The quantification of the occurrence of pathologies within taxa and across guilds is critical to constructing more detailed hypotheses regarding changes in the prevalence of skeletal injury and disease through Earth history.", "keyphrases": ["skeletal health", "germany", "disease"]}
{"id": "10.1086/688707", "title": "Krassiloviella limbelloides gen. et sp. nov.: Additional Diversity in the Hypnanaean Moss Family Tricostaceae (Valanginian, Vancouver Island, British Columbia)", "abstract": "Premise of research.\u2003Despite an increase in interest in the fossil record of bryophytes (i.e., liverworts, hornworts, and mosses), the biology and taxonomy of these organisms remain understudied and, at times, elusive. In the pre-Cenozoic, especially, few taxonomically informative moss fossils are known. From this perspective, the anatomically preserved Apple Bay flora of Vancouver Island holds a wealth of Cretaceous moss diversity that, until very recently, has remained unexplored. Methodology.\u2003Fossils are preserved anatomically in carbonate concretions and studied in serial sections prepared using the cellulose acetate peel technique. Pivotal results.\u2003Krassiloviella limbelloides gen. et sp. nov., defined by tricostate homocostate leaves and much-branched stems, is a new addition to the pleurocarpous moss family Tricostaceae (superorder Hypnanae). Conclusions.\u2003Krassiloviella limbelloides is the second bryophyte described as a result of ongoing studies of the Early Cretaceous Apple Bay flora of Vancouver Island. Krassiloviella is also the second genus of family Tricostaceae, which provides the oldest unequivocal evidence for the pleurocarpous superorder Hypnanae and a hard minimum age for the group. Revealing aspects of diversity unaccounted for in extant floras, such fossil bryophyte discoveries emphasize the importance of paleontology for efforts aimed at documenting the history of biodiversity.", "keyphrases": ["vancouver island", "bryophyte", "carbonate concretion", "krassiloviella"]}
{"id": "10.1098/rspb.2011.1430", "title": "Cretaceous origin and repeated tertiary diversification of the redefined butterflies", "abstract": "Although the taxonomy of the ca 18 000 species of butterflies and skippers is well known, the family-level relationships are still debated. Here, we present, to our knowledge, the most comprehensive phylogenetic analysis of the superfamilies Papilionoidea, Hesperioidea and Hedyloidea to date based on morphological and molecular data. We reconstructed their phylogenetic relationships using parsimony and Bayesian approaches. We estimated times and rates of diversification along lineages in order to reconstruct their evolutionary history. Our results suggest that the butterflies, as traditionally understood, are paraphyletic, with Papilionidae being the sister-group to Hesperioidea, Hedyloidea and all other butterflies. Hence, the families in the current three superfamilies should be placed in a single superfamily Papilionoidea. In addition, we find that Hedylidae is sister to Hesperiidae, and this novel relationship is supported by two morphological characters. The families diverged in the Early Cretaceous but diversified after the Cretaceous\u2013Palaeogene event. The diversification of butterflies is characterized by a slow speciation rate in the lineage leading to Baronia brevicornis, a period of stasis by the skippers after divergence and a burst of diversification in the lineages leading to Nymphalidae, Riodinidae and Lycaenidae.", "keyphrases": ["diversification", "hedylidae", "hesperiidae"]}
{"id": "10.1002/ece3.100", "title": "Integrating species distribution models (SDMs) and phylogeography for two species of Alpine Primula", "abstract": "The major intention of the present study was to investigate whether an approach combining the use of niche-based palaeodistribution modeling and phylo-geography would support or modify hypotheses about the Quaternary distributional history derived from phylogeographic methods alone. Our study system comprised two closely related species of Alpine Primula. We used species distribution models based on the extant distribution of the species and last glacial maximum (LGM) climate models to predict the distribution of the two species during the LGM. Phylogeographic data were generated using amplified fragment length polymorphisms (AFLPs). In Primula hirsuta, models of past distribution and phylogeographic data are partly congruent and support the hypothesis of widespread nunatak survival in the Central Alps. Species distribution models (SDMs) allowed us to differentiate between alpine regions that harbor potential nunatak areas and regions that have been colonized from other areas. SDMs revealed that diversity is a good indicator for nunataks, while rarity is a good indicator for peripheral relict populations that were not source for the recolonization of the inner Alps. In P. daonensis, palaeo-distribution models and phylogeographic data are incongruent. Besides the uncertainty inherent to this type of modeling approach (e.g., relatively coarse 1-km grain size), disagreement of models and data may partly be caused by shifts of ecological niche in both species. Nevertheless, we demonstrate that the combination of palaeo-distribution modeling with phylogeographical approaches provides a more differentiated picture of the distributional history of species and partly supports (P. hirsuta) and partly modifies (P. daonensis and P. hirsuta) hypotheses of Quaternary distributional history. Some of the refugial area indicated by palaeodistribution models could not have been identified with phylogeographic data.", "keyphrases": ["sdms", "alpine primula", "distributional history", "picture"]}
{"id": "10.1080/14772019.2016.1228549", "title": "A new turtle taxon (Podocnemidoidea, Bothremydidae) reveals the oldest known dispersal event of the crown Pleurodira from Gondwana to Laurasia", "abstract": "Pan-Pleurodira is one of the two clades of extant turtles (i.e. Testudines). Its crown group, Pleurodira, has a Gondwanan origin being known from the Barremian. Cretaceous turtle fauna of Gondwana was composed almost exclusively of pleurodires. Extant pleurodires live in relatively warm regions, with a geographical distribution restricted to tropical regions that were part of Gondwana. Although pleurodires were originally freshwater forms, some clades have adapted to a nearshore marine lifestyle, which contributed to their dispersal. However, few lineages of Pleurodira reached Laurasian regions and no representatives have so far been described from the pre-Santonian of Laurasia, where the continental and coastal Cretaceous faunas of turtles consist of clades exclusive to this region. A new turtle, Algorachelus peregrinus gen. et sp. nov., is described here from the southern Laurasian Cenomanian site of Algora in Spain. Numerous remains, including a skull and well-preserved postcranial specimens, are attributed to this species. The abundant shell elements, much more numerous than those known in most members of pleurodiran clade Bothremydidae, allow its variability to be studied. The new taxon represents the oldest evidence of the occurrence of Pleurodira in Laurasia, and is the oldest genus of the abundant and diverse Bothremydodda so far described. Factors such as the relatively high Cenomanian temperatures, the adaptation of this Gondwanan clade to coastal environments, and the geographical proximity between the two landmasses may have contributed to its dispersal. This finding shows that the first dispersals of Pleurodira from Gondwana to Laurasia occurred much earlier than previously thought. http://zoobank.org/urn:lsid:zoobank.org:pub:8FD358A5-53BD-4308-828A-AC6802184185", "keyphrases": ["bothremydidae", "cenomanian site", "old genus"]}
{"id": "10.2517/PR210001", "title": "Morphological Function of Trace Fossil Paleodictyon: an Approach from Fluid Simulation", "abstract": "Abstract. This study examined the functional morphology of the trace fossil Paleodictyon in terms of computational fluid dynamics. The modern specimens show a unique morphology that is composed of a hexagonal mesh structure, vertical shafts opening to the seafloor, and a shield-like mound on the seafloor. The traces of the vertical shafts were also preserved in some fossil examples. To explain their characteristic morphology, a \u201cpassive ventilation\u201d hypothesis has been proposed suggesting that their function was to ventilate their burrows with bottom currents, which supply both oxygenated water and food. However, this hypothesis has not yet been verified. This study conducted numerical experiments to understand the functions of the structures created by this ichnofossil by using a model of computational fluid dynamics with the 3D geometry of Paleodictyon and estimating the efficiency of the ventilation in burrows. As a result, it was observed that seawater flowed in the vertical shafts in the marginal area of the mound, and flowed out from the shafts located on the top of the mound, flowing through the mesh structure. This ventilation was observed only in the case that Paleodictyon had a shield-like mound. The ventilation rate rapidly increased as the bottom current velocity increased. In contrast, the rate also increased with the height of the shield-like mounds, whereas it once dropped after the minor peak at 4 mm in height, which corresponds to the value measured in the modern specimens. This coincidence may imply that the height of the mound observed in modern specimens resulted from the optimization in balancing between the efficiency of ventilation and physical stability against erosion. Full exchange of water in the mesh structure by ventilation took less than a few minutes at this mound height, which is presumably sufficient for the ability of Paleodictyon producers.", "keyphrases": ["trace fossil paleodictyon", "physical stability", "erosion"]}
{"id": "10.1017/S0266467418000202", "title": "Assembly and division of the South and South-East Asian flora in relation to tectonics and climate change", "abstract": "Abstract: The main phases of plant dispersal into, and out of the South-East Asian region are discussed in relation to plate tectonics and changing climates. The South-East Asian area was a backwater of angiosperm evolution until the collision of the Indian Plate with Asia during the early Cenozoic. The Late Cretaceous remains poorly understood, but the Paleocene topography was mountainous, and the climate was probably seasonally dry, with the result that frost-tolerant conifers were common in upland areas and a low-diversity East Asian aspect flora occurred at low altitudes. India's drift into the perhumid low latitudes during the Eocene brought opportunities for the dispersal into South-East Asia of diverse groups of megathermal angiosperms which originated in West Gondwana. They successfully dispersed and became established across the South-East Asian region, initially carried by wind or birds, beginning at about 49 Ma, and with a terrestrial connection after about 41 Ma. Many Paleocene lineages probably went extinct, but a few dispersed in the opposite direction into India. The Oligocene was a time of seasonally dry climates except along the eastern and southern seaboard of Sundaland, but with the collision of the Australian Plate with Sunda at the end of the Oligocene widespread perhumid conditions became established across the region. The uplift of the Himalaya, coinciding with the middle Miocene thermal maximum, created opportunities for South-East Asian evergreen taxa to disperse into north India, and then with the late Miocene strengthening of the Indian monsoon, seasonally dry conditions expanded across India and Indochina, resulting eventually in the disappearance of closed forest over much of the Indian peninsula. This drying affected Sunda, but it is thought unlikely that a \u2018savanna\u2019 corridor was present across Sunda during the Pleistocene. Some dispersals from Australasia occurred following its collision with Sunda and following the uplift of New Guinea and the islands of Wallacea, Gondwanan montane taxa also found their way into the region. Phases of uplift across the Sunda region created opportunities for allopatric speciation and further dispersal opportunities. There is abundant evidence to suggest that the Pleistocene refuge theory applies to the South-East Asian region.", "keyphrases": ["flora", "tectonic", "cenozoic", "australian plate", "speciation"]}
{"id": "paleo.002207", "title": "A new family of Cambrian rhynchonelliformean brachiopods (Order Naukatida) with an aberrant coral\u2010like morphology", "abstract": "Tomteluva perturbata gen. et sp. nov. and Nasakia thulensis gen. et sp. nov., two new rhynchonelliformean brachiopod taxa, are described from carbonate beds from the lower middle Cambrian (Series 3, Stage 5) basinal Stephen Formation, Canada, and the upper lower Cambrian (Series 2, Stage 4) Henson Gletscher Formation, North Greenland, respectively. The two taxa are characterized by an unusual coral\u2010like morphology typified by a high conical ventral valve with an anteriorly curved umbo and a tube\u2010like structure inside the ventral valve, interpreted as pedicle tube. Both resemble the problematic late middle Cambrian (Drumian) species Anomalocalyx cawoodi Brock from Australia, whose systematic affiliation is controversial. Together, the three genera are interpreted as representatives of a new family of rhynchonelliformean brachiopods, the Tomteluvidae fam. nov., which is interpreted as an aberrant or derived taxon within the Order Naukatida. Convergence between the Tomteluvidae and the coralla of small solitary Cambrian coralimorphs, as well as the late Palaeozoic reef\u2010building richthofenioid brachiopods, might indicate adaptation to a similar life habits and environments. However, their small size (length 4 mm), well\u2010developed pedicle and perfect morphological symmetry make it more likely that tomteluvids lived attached to frondose algae or sponges, above the seafloor, in a similar fashion to the acrotretoid brachiopods with which they show a high degree of morphological convergence. Morphological features of the pedicle tube of N. thulensis suggest that the tomteluvid pedicle is homologous to that in modern rhynchonelliformean brachiopods. This is the first evidence of the pedicle type within the Naukatida and represents the oldest confirmation of a rhynchonellate pedicle.", "keyphrases": ["new family", "rhynchonelliformean brachiopod", "order naukatida", "carbonate bed", "stephen formation"]}
{"id": "10.1029/2008pa001676", "title": "Coupled Greenhouse Warming and Deep Sea Acidification in the Middle Eocene", "abstract": "[1]\u00a0The Middle Eocene Climatic Optimum (MECO) is an enigmatic warming event that represents an abrupt reversal in long-term cooling through the Eocene. In order to further assess the timing and nature of this event, we have assembled stable isotope and calcium carbonate concentration records from multiple Deep Sea Drilling Project and Ocean Drilling Program sites for the time interval between \u223c43 and 38 Ma. Revised stratigraphy at several sites and compilation of \u03b418O records place peak warming during the MECO event at 40.0 Ma (Chron C18n.2n). The identification of the \u03b418O excursion at sites in different geographic regions indicates that the climatic effects of this event were globally extensive. The total duration of the MECO event is estimated at \u223c500 ka, with peak warming lasting <100 ka. Assuming minimal glaciation in the late middle Eocene, \u223c4\u00b0\u20136\u00b0C total warming of both surface and deep waters is estimated during the MECO at the study sites. The interval of peak warming at \u223c40.0 Ma also coincided with a worldwide decline in carbonate accumulation at sites below 3000 m depth, reflecting a temporary shoaling of the calcite compensation depth. The synchroneity of deep-water acidification and globally extensive warming makes a persuasive argument that the MECO event was linked to a transient increase in atmospheric pCO2. The results of this study confirm previous reports of significant climatic instability during the middle Eocene. Furthermore, the direct link between warming and changes in the carbonate chemistry of the deep ocean provides strong evidence that changes in greenhouse gas concentrations exerted a primary control on short-term climate variability during this critical period of Eocene climate evolution.", "keyphrases": ["warming", "middle eocene", "meco"]}
{"id": "10.1002/spp2.1296", "title": "Neuroanatomical and neurosensorial analysis of the Late Cretaceous basal eusuchian Agaresuchus fontisensis (Cuenca, Spain)", "abstract": "Agaresuchus fontisensis is an allodaposuchid crocodile from the Campanian\u2013Maastrichtian (Late Cretaceous) of Lo Hueco (Cuenca, Spain). Allodaposuchidae is a clade of European basal eusuchians, which is considered a part of the stem group of Crocodylia. The holotype and paratype skulls of Agaresuchus fontisensis were scanned on computed tomography and their internal cavities, including those of the brain, nerves and blood vessels, as well as the paratympanic sinus system and the paranasal sinuses, digitally reconstructed. The cranial endocast and pneumatic sinuses were then compared with those of other crocodyliforms. The neuroanatomy of Agaresuchus fontisensis resembles those of other mesoeucrocodylians, sharing some morphological traits with extant crocodiles. The neurosensorial and cognitive capabilities inferred from the inner skull cavity reconstructions of Agaresuchus fontisensis are similar to those of other eusuchians. The olfactory acuity of Agaresuchus fontisensis is low by crocodylian standards, closer to that of the alligatoroids rather than to that of the crocodyloids. Its visual acuity is similar to that of Lohuecosuchus megadontos, a sympatric allodaposuchid also found in the fossil site of Lo Hueco.", "keyphrases": ["cuenca", "spain", "crocodile"]}
{"id": "paleo.006212", "title": "MICROWEAR IN MODERN SQUIRRELS IN RELATION TO DIET", "abstract": "Dental microwear consists of microscopic damage features on the occlusal surfaces of tooth enamel and reflects physical properties of the diet, as well as enamel structure and post-mortem history of the tooth. Microwear analysis has been used to infer the diets of extinct mammals through comparison of features on fossil teeth with those on teeth of living mammals with known diets. A method for documenting microwear of large mammals using a light microscope was developed as an alternative to approaches based on scanning electron microscopy. We adapted this method for investigating microwear features on squirrel teeth. Both modern and fossil squirrels occur in diverse terrestrial habitats and eat a range of herbivorous to omnivorous diets.\nWe compared microwear features from upper molars of several modern species of frugivorous tree squirrels and omnivorous ground squirrels. We also examined fossil sciurids from the Miocene Siwalik sequence of Pakistan and a Pliocene locality in the central plains of the United States. We found significant differences in microwear features among modern squirrels of different diets and habitats, suggesting that microwear features can be used to infer the diets or preferred habitats of extinct species. Microwear features were preserved on some of the fossil specimens. A comparison of Pliocene Spermophilus rexroadensis to modern Spermophilus suggests a diet similar to that of the modern species examined. Microwear of Miocene Eutamias differed from the pattern in any of the living squirrels examined. The approach presented here holds strong potential for illuminating the trophic ecomorphology of small-mammal fossils.", "keyphrases": ["microscope", "extinct specie", "microwear"]}
{"id": "10.1029/PA003i003p00343", "title": "Deepwater source variations during the last climatic cycle and their impact on the global deepwater circulation", "abstract": "The degree of similarity of the \u220213C records of the planktonic foraminiferal species N. pachyderma and of the benthic foraminiferal genus Cibicides in the high-latitude basins of the world ocean is used as an indicator of the presence of deepwater sources during the last climatic cycle. Whereas continuous formation of deep water is recognized in the southern ocean, the Norwegian Sea stopped acting as a sink for surface water during isotope stage 4 and the remainder of the last glaciation. However, deep water formed in the north Atlantic south of the Norwegian Sea during the last climatic cycle as early as isotope substage 5d, and this area was also the only active northern source during stages 4\u20132. A detailed reconstruction of the geographic distribution of \u220213C in benthic foraminifera in the Atlantic Ocean during the last glacial maximum shows that the most important deepwater mass originated from the southern ocean, whereas the Glacial North Atlantic Deep Water cannot be traced south of 40\u00b0N. At shallower depth an oxygenated 13C rich Intermediate Water mass extended from 45\u00b0N to 15\u00b0S. In the Pacific Ocean a ventilation higher than the modern one was also found in open ocean in the depth range 700\u20132600 m and is best explained by stronger formation of Intermediate Water in high northern latitudes.", "keyphrases": ["last climatic cycle", "ocean", "north atlantic"]}
{"id": "10.1371/journal.pone.0197214", "title": "5000 years of dietary variations of prehistoric farmers in the Great Hungarian Plain", "abstract": "The development of farming was a catalyst for the evolution of the human diet from the varied subsistence practices of hunter-gatherers to the more globalised food economy we depend upon today. Although there has been considerable research into the dietary changes associated with the initial spread of farming, less attention has been given to how dietary choices continued to develop during subsequent millennia. A paleogenomic time transect for 5 millennia of human occupation in the Great Hungarian Plain spanning from the advent of the Neolithic to the Iron Age, showed major genomic turnovers. Here we assess where these genetic turnovers are associated with corresponding dietary shifts, by examining the carbon and nitrogen stable isotope ratios of 52 individuals. Results provide evidence that early Neolithic individuals, which were genetically characterised as Mesolithic hunter-gatherers, relied on wild resources to a greater extent than those whose genomic attributes were of typical Neolithic European farmers. Other Neolithic individuals and those from the Copper Age to Bronze Age periods relied mostly on terrestrial C3 plant resources. We also report a carbon isotopic ratio typical of C4 plants, which may indicate millet consumption in the Late Bronze Age, despite suggestions of the crop\u2019s earlier arrival in Europe during the Neolithic.", "keyphrases": ["farmer", "great hungarian plain", "bronze age"]}
{"id": "10.1111/j.1502-3931.2007.00032.x", "title": "Things that go bump in the night: evolutionary interactions between cephalopods and cetaceans in the tertiary", "abstract": "Echolocation has evolved independently in several vertebrate groups, and hypotheses about the origin of echolocation in these groups often invoke abiotic mechanisms driving morphological evolution. In bats, for example, the ecological setting associated with the origin of echolocation has been linked to global warming during the Palaeocene\u2013Eocene; similarly, the origin of toothed whales (odontocetes) has been broadly correlated with the establishment of the circum-Antarctic current. These scenarios, and the adaptational hypotheses for the evolution of echolocation with which they are associated, neglect a consideration of possible biotic mechanisms. Here we propose that the origin of echolocation in odontocetes was initially an adaptation for nocturnal epipelagic feeding \u2013 primarily on diel migrating cephalopods. We test this hypothesis using data on the temporal, geographical, and water column distributions of odontocetes and cephalopods, and other global events from their respective tertiary histories. From this analysis, we suggest that echolocation in early odontocetes aided nocturnal feeding on cephalopods and other prey items, and that this early system was exapted for deep diving and hunting at depths below the photic zone where abundant cephalopod resources were available 24\u00a0h a day. This scenario extends to the evolution of other cephalopod feeding (teuthophagous) marine vertebrates such as pinnipeds and Mesozoic marine reptiles.", "keyphrases": ["cephalopod", "echolocation", "odontocete"]}
{"id": "paleo.000535", "title": "Multi-proxy dentition analyses reveal niche partitioning between sympatric herbivorous dinosaurs", "abstract": "Dentitions of the sympatric herbivorous dinosaurs Hungarosaurus (Ankylosauria, Nodosauridae) and Mochlodon (Ornithopoda, Rhabdodontidae) (Santonian, Hungary) were analysed to investigate their dietary ecology, using several complementary methods-orientation patch count, tooth replacement rate, macrowear, tooth wear rate, traditional microwear, and dental microwear texture analysis (DMTA). Tooth formation time is similar in Hungarosaurus and Mochlodon, and traditional and DMTA microwear features suggest low-browsing habits for both taxa, consistent with their inferred stances and body sizes. However, Mochlodon possesses a novel adaptation for increasing dental durability: the dentine on the working side of the crown is double the thickness of that on the balancing side. Moreover, crown morphology, enamel thickness, macrowear orientation, and wear rate differ greatly between the two taxa. Consequently, these sympatric herbivores probably exploited plants of different toughness, implying dietary selectivity and niche partitioning. Hungarosaurus is inferred to have eaten softer vegetation, whereas Mochlodon likely fed on tougher material. Compared to the much heavier, quadrupedal Hungarosaurus, the bipedal Mochlodon wore down more than twice as much of its crown volume during the functional life of the tooth. This heavy tooth wear might correlate with more intensive food processing and, in turn, could reflect differences in the metabolic requirements of these animals.", "keyphrases": ["dentition", "dietary ecology", "microwear"]}
{"id": "10.4202/app.00648.2019", "title": "The last erythrosuchid\u2014a revision of Chalishevia cothurnata from the late Middle Triassic of European Russia", "abstract": "Erythrosuchidae is a clade of early archosauriform reptiles that were large-bodied, hypercarnivorous, possibly apex predators in late Early and Middle Triassic ecosystems following the Permo-Triassic mass extinction. Chalishevia cothurnata from the late Middle Triassic (Ladinian) of Russia, is the stratigraphically youngest known erythrosuchid species, but the holotype and referred material of this taxon has received little study. Here, we provide the first detailed anatomical description of C. cothurnata , including comparisons to other erythrosuchids. Although known from relatively fragmentary material, the anatomy of C. cothurnata is distinctive, including an autapomorphic strongly slanted ventral border of the antorbital fossa. The presence of a large accessory opening (the \u201caccessory antorbital fenestra\u201d) in the skull between the premaxilla, nasal and maxilla, together with the inferred presence of a narrow postnarial process of the premaxilla that articulated with a slot on the nasal, provides strong evidence for a sister taxon relationship between C. cothurnata and the erythrosuchid Shansisuchus shansisuchus from the early Middle Triassic (Anisian) of China. The inferred basal skull length of C. cothurnata was approximately 80 cm, making it one of the largest erythrosuchids known.", "keyphrases": ["chalishevia cothurnata", "late middle triassic", "erythrosuchidae", "permo-triassic mass extinction", "china"]}
{"id": "10.1017/jpa.2016.67", "title": "Morphology of the Radiodontan Lyrarapax from the Early Cambrian Chengjiang Biota", "abstract": "Abstract. \n The recently described radiodontan Lyrarapax unguispinus Cong et al., 2014 from the Chengjiang biota (Cambrian Series 2, Stage 3) highlighted a new morphological type of frontal appendage and unique mouth structures, a functional combination reinforcing the diversification of feeding strategies of radiodontans during the early Cambrian. Here we describe Lyrarapax trilobus n. sp. from the same fossil Konservat-Lagerst\u00e4tte. The new species differs from L. unguispinus in the morphology and distribution of endites on the frontal appendage and the strengthening structure of the body flaps. The two species resemble each other in body shape (pattern of flap size), neck segment number, cephalic plates, and most importantly a mouth characterized by concentric wrinkled furrows. The latter confirms that a soft mouth without sclerotized plates is a real feature of Lyrarapax and supports the idea that oral structures provide valid diagnostic characters within Radiodonta.", "keyphrases": ["radiodontan", "lyrarapax", "chengjiang biota", "morphology"]}
{"id": "paleo.009929", "title": "Allodaposuchus palustris sp. nov. from the Upper Cretaceous of Fumanya (South-Eastern Pyrenees, Iberian Peninsula): Systematics, Palaeoecology and Palaeobiogeography of the Enigmatic Allodaposuchian Crocodylians", "abstract": "The controversial European genus Allodaposuchus is currently composed of two species (A. precedens, A. subjuniperus) and it has been traditionally considered a basal eusuchian clade of crocodylomorphs. In the present work, the new species A. palustris is erected on the base of cranial and postcranial remains from the lower Maastrichtian of the southern Pyrenees. Phylogenetic analyses here including both cranial and postcranial data support the hypothesis that Allodaposuchus is included within Crocodylia. The studied specimen suggests little change in postcranial skeleton along the evolutionary history of crocodylians, except for some bone elements such as the axis, the first caudal vertebra and the ilium. The specimen was found in an organic mudstone corresponding to a coastal wetland environment. Thus, A. palustris from Fumanya is the first Allodaposuchus reported in lacustrine-palustrine settings that expand the ecological range for this genus. The S-DIVA palaeobiogeographic reconstruction of ancestral area suggests that early members of Crocodylia rapidly widespread for the Northern Hemisphere landmasses no later than the Campanian, leading the apparition of endemic groups. In that way \u201cAllodaposuchia\u201d represents an endemic European clade probably originated in the Ibero-Armorican domain in the late Campanian and dispersed by the Southern European archipelago prior to the early Maastrichtian.", "keyphrases": ["palaeobiogeography", "crocodylia", "allodaposuchus", "phylogenetic analysis"]}
{"id": "paleo.004737", "title": "DIVERSITY ESTIMATES, BIASES, AND HISTORIOGRAPHIC EFFECTS: RESOLVING CETACEAN DIVERSITY IN THE TERTIARY", "abstract": "The number of cetacean genera varied greatly over their evolutionary history. Cetaceans originated in the Eocene and then rapidly diversified, reaching around 30 genera during the Middle Eocene. The number of genera crashed in the late Eocene, with only eight described from the early Oligocene. This time also represents the putative extinction of archaeocetes and the origin of Neoceti, the clade including extant cetaceans. By the late Oligocene, the number of genera recovered and had begun an expansion that peaked in the middle Miocene, at over 75 genera. Since that time, the number of genera has decreased to around 40 genera extant today.\nIdeally, generic counts reflect the actual number of genera in the past (generic richness), but our understanding of past diversity is confounded by many factors. Generic counts are potentially too high because of the prevalence of genera based on non-diagnostic material and taxonomic over-splitting. Taxonomic counts can also appear to be too high if the counts are made in time intervals that are excessively long. Conversely, generic counts are potentially too low because of fossil non-preservation; non-deposition, destruction, or obscured fossil-bearing, continental shelf rocks; and lack of collecting or publication effort. We evaluate each of these factors as a cause of bias in cetacean diversity. Individual causes may have significant effects on both true generic richness and the amount of bias. These factors must be addressed in any evaluations of past diversity, especially for clades represented by an abundance of fossils.", "keyphrases": ["cetacean diversity", "richness", "time interval", "uhen"]}
{"id": "paleo.011413", "title": "Effects of Global Warming on Ancient Mammalian Communities and Their Environments", "abstract": "Background Current global warming affects the composition and dynamics of mammalian communities and can increase extinction risk; however, long-term effects of warming on mammals are less understood. Dietary reconstructions inferred from stable isotopes of fossil herbivorous mammalian tooth enamel document environmental and climatic changes in ancient ecosystems, including C3/C4 transitions and relative seasonality. Methodology/Principal Findings Here, we use stable carbon and oxygen isotopes preserved in fossil teeth to document the magnitude of mammalian dietary shifts and ancient floral change during geologically documented glacial and interglacial periods during the Pliocene (\u223c1.9 million years ago) and Pleistocene (\u223c1.3 million years ago) in Florida. Stable isotope data demonstrate increased aridity, increased C4 grass consumption, inter-faunal dietary partitioning, increased isotopic niche breadth of mixed feeders, niche partitioning of phylogenetically similar taxa, and differences in relative seasonality with warming. Conclusion/Significance Our data show that global warming resulted in dramatic vegetation and dietary changes even at lower latitudes (\u223c28\u00b0N). Our results also question the use of models that predict the long term decline and extinction of species based on the assumption that niches are conserved over time. These findings have immediate relevance to clarifying possible biotic responses to current global warming in modern ecosystems.", "keyphrases": ["global warming", "tooth enamel", "oxygen isotope"]}
{"id": "paleo.003480", "title": "OLIGOCENE TERRESTRIAL STRATA OF NORTHWESTERN ETHIOPIA: A PRELIMINARY REPORT ON PALEOENVIRONMENTS AND PALEONTOLOGY", "abstract": "The Paleogene record of Afro-Arabia is represented by few fossil localities, most of which are coastal. Here we report sedimentological and paleontological data from continental Oligocene strata in northwestern Ethiopia. These have produced abundant plant fossils and unique assemblages of vertebrates, thus filling a gap in what is known of Paleogene interior Afro-Arabia. The study area is approximately 60 km west of Gondar, Chilga Woreda; covers about 100 km 2 ; and represents as few as 1 Myr based on radiometric dates and paleomagnetic chronostratigraphy. The sedimentary strata are 150 m thick, and dominated by kaolinitic and smectitic mudstones and airfall tuff deposits. Five main paleosol types are interpreted as representing Protosols (gleyed or ferric), Histosols, Gleysols, Vertisols, and Argillisols. Varied, poor drainage conditions produced lateral variation in paleosols, and stratigraphic variation probably resulted from lateral changes in drainage conditions through time. Vertebrate fossils occur in sediments associated with ferric Protosols and occur with fruits, seeds, and leaf impressions. Plant fossils also occur as in situ forests on interfluves, leaf and flower compressions associated with in situ carbonized trees in overbank deposits (Gleyed Protosols), and compressions of leaves, twigs and seeds in tuffs. Plant fossil assemblages document diverse forests, from 20-35 m tall, of locally heterogeneous composition, and representing families occurring commonly (legumes) or uncommonly (palms) in forests today. Sedimentological and paleobotanical data are consistent with a nearly flat landscape where a meandering river and ample rainfall supported lush vegetation. Over time, the region was subject to intermittent ashfalls. A unique fauna of archaic mammalian endemics, such as arsinoitheres and primitive hyracoids, lived here with the earliest deinotheres.", "keyphrases": ["northwestern ethiopia", "oligocene strata", "paleosol"]}
{"id": "paleo.003262", "title": "Ancient collagen reveals evolutionary history of the endemic South American \u2018ungulates\u2019", "abstract": "Since the late eighteenth century, fossils of bizarre extinct creatures have been described from the Americas, revealing a previously unimagined chapter in the history of mammals. The most bizarre of these are the \u2018native\u2019 South American ungulates thought to represent a group of mammals that evolved in relative isolation on South America, but with an uncertain affinity to any particular placental lineage. Many authors have considered them descended from Laurasian \u2018condylarths\u2019, which also includes the probable ancestors of perissodactyls and artiodactyls, whereas others have placed them either closer to the uniquely South American xenarthrans (anteaters, armadillos and sloths) or the basal afrotherians (e.g. elephants and hyraxes). These hypotheses have been debated owing to conflicting morphological characteristics and the hitherto inability to retrieve molecular information. Of the \u2018native\u2019 South American mammals, only the toxodonts and litopterns persisted until the Late Pleistocene\u2013Early Holocene. Owing to known difficulties in retrieving ancient DNA (aDNA) from specimens from warm climates, this research presents a molecular phylogeny for both Macrauchenia patachonica (Litopterna) and Toxodon platensis (Notoungulata) recovered using proteomics-based (liquid chromatography\u2013tandem mass spectrometry) sequencing analyses of bone collagen. The results place both taxa in a clade that is monophyletic with the perissodactyls, which today are represented by horses, rhinoceroses and tapirs.", "keyphrases": ["ungulate", "perissodactyls", "litopterna"]}
{"id": "10.1080/14772019.2010.499137", "title": "Ordovician edrioasteroids from Morocco: faunal exchanges across the Rheic Ocean", "abstract": "A new edrioasteroid fauna from the Ordovician of Morocco, North Africa includes eight new isorophid species placed in six genera of which three are new. A phylogenetic analysis of Moroccan genera and other taxa places these new edrioasteroids into a phylogenetic framework. Pyrgocystidae is redefined to include plesiomorphic isorophids with hood plates underlying the cover plates. New pyrgocystid taxa include Streptaster nodosus sp. nov., Belochthus? chauveli sp. nov., Argodiscus espilezorum sp. nov. and Moroccopyrgus matacarros gen. et sp. nov. Isorophinid taxa include Isorophus africanus sp. nov., Isorophusella gutii sp. nov., Euryeschatia reboulorum gen. et sp. nov. and the morphological aberrant Anedriophus moroccoensis gen. et sp. nov. These taxa are attached either epibiotically on conulariids or echinosphaeritid rhombiferans, or encrust large bioclasts such as cephalopods and trilobites in a siliciclastic environment that is otherwise devoid of suitable hard substrates. The presence of close relatives of North American taxa in this Perigondwanan section indicates a high degree of communication between North America and North Africa in Ordovician time. Also described are two species of an unusual eocrinoid? Hexedriocystis gen. nov., the type species H. inexpectatus sp. nov. and H. mimus sp. nov., that is a close mimic of isorophid taxa.", "keyphrases": ["edrioasteroid", "morocco", "phylogenetic analysis"]}
{"id": "paleo.003323", "title": "Coryphodon, the northernmost Holarctic Paleogene pantodont (Mammalia), and its global wanderings", "abstract": "The pantodont Coryphodon is a frequently found component of early Eocene terrestrial faunas in North America, distributed widely from the Arctic to the Gulf Coast. The most northerly member of this genus of large herbivore is a new species that appears to be closest to the oldest known mid-latitude species, Coryphodon proterus from the Clarkforkian (Cf-2), late Paleocene, of Montana. Coryphodon is widely distributed during the early Eocene across the Holarctic, occurring also in England, Belgium, and France (MP7-9, early Eocene) on the one hand and Kazakhstan, Mongolia, and China (Gashatan-Bumbanian, late Paleocene-early Eocene, Xinjiang, Shandong, and Shanxi) on the other. Although other genera of Coryphodontidae, as well as of other pantodont families, appear to have had more sedentary habits, Coryphodon is noted for its wide distribution. Adaptations to a warm temperate northern climate, including its northern light regime, may be postulated for this genus of pantodont as well as a pattern of dispersal leading to its wide range across the Holarctic.", "keyphrases": ["north america", "dispersal", "coryphodon"]}
{"id": "10.1080/02724634.1992.10011463", "title": "The skull of the basal stegosaur Huayangosaurus taibaii and a cladistic diagnosis of stegosauria", "abstract": "ABSTRACT The recent discovery of the Middle Jurassic stegosaur, Huayangosaurus taibaii has shed new light on the early phylogeny of Stegosauria. The skull of this taxon is described in detail and compared to those of other thyreophorans. Cranial and postcranial autapomorphies of Huayangosaurus include high premaxillary and maxillary tooth counts (7 and 25\u201330, respectively), small postorbital horn, intercostal articular flanges, and a carpus composed of a single coossified block. Nineteen synapomorphies unite Huayangosaurus and other stegosaurs and constitute a revised cladistic diagnosis for Stegosauria. Huayangosaurus is the sister-taxon to all other stegosaurs, which have lost premaxillary teeth, reduced the size of the antorbital fossa, increased the length of the prepubic process of the pubis, and lost lateral scute rows along the trunk.", "keyphrases": ["skull", "huayangosaurus", "cladistic diagnosis", "stegosauria", "other thyreophoran"]}
{"id": "paleo.008634", "title": "Osteohistological analyses reveal diverse strategies of theropod dinosaur body-size evolution", "abstract": "The independent evolution of gigantism among dinosaurs has been a topic of long-standing interest, but it remains unclear if gigantic theropods, the largest bipeds in the fossil record, all achieved massive sizes in the same manner, or through different strategies. We perform multi-element histological analyses on a phylogenetically broad dataset sampled from eight theropod families, with a focus on gigantic tyrannosaurids and carcharodontosaurids, to reconstruct the growth strategies of these lineages and test if particular bones consistently preserve the most complete growth record. We find that in skeletally mature gigantic theropods, weight-bearing bones consistently preserve extensive growth records, whereas non-weight-bearing bones are remodelled and less useful for growth reconstruction, contrary to the pattern observed in smaller theropods and some other dinosaur clades. We find a heterochronic pattern of growth fitting an acceleration model in tyrannosaurids, with allosauroid carcharodontosaurids better fitting a model of hypermorphosis. These divergent growth patterns appear phylogenetically constrained, representing extreme versions of the growth patterns present in smaller coelurosaurs and allosauroids, respectively. This provides the first evidence of a lack of strong mechanistic or physiological constraints on size evolution in the largest bipeds in the fossil record and evidence of one of the longest-living individual dinosaurs ever documented.", "keyphrases": ["strategy", "theropod", "growth strategy"]}
{"id": "paleo.012318", "title": "New records of the dolphin Albertocetus meffordorum (Odontoceti: Xenorophidae) from the lower Oligocene of South Carolina: Encephalization, sensory anatomy, postcranial morphology, and ontogeny of early odontocetes", "abstract": "We report five new specimens of xenorophid dolphins from North and South Carolina. Four of the specimens represent the xenorophid Albertocetus meffordorum, previously only known from the holotype skull. The other is a fragmentary petrosal from the upper Oligocene Belgrade Formation that we refer to Echovenator sp, indicating at least two xenorophids from that unit. Two of the Albertocetus meffordorum specimens are from the lower Oligocene Ashley Formation: 1) a partial skeleton with neurocranium, fragmentary mandible, ribs, vertebrae, and chevrons, and 2) an isolated braincase. The partial vertebral column indicates that Albertocetus retained the ancestral morphology and locomotory capabilities of basilosaurid archaeocetes, toothed mysticetes, and physeteroids, and caudal vertebrae that are as wide as tall suggest that the caudal peduncle, which occurs in all extant Cetacea, was either wide or lacking. CT data from the isolated braincase were used to generate a digital endocast of the cranial cavity. The estimated EQ of this specimen is relatively high for an Oligocene odontocete, and other aspects of the brain, such as its anteroposterior length and relative size of the temporal lobe, are intermediate in morphology between those of extant cetaceans and terrestrial artiodactyls. Ethmoturbinals are also preserved, and are similar in morphology and number to those described for the Miocene odontocete Squalodon. These fossils extend the temporal range of Albertocetus meffordorum into the early Oligocene, its geographic range into South Carolina, and expand our paleobiological understanding of the Xenorophidae.", "keyphrases": ["xenorophidae", "oligocene", "cranial cavity", "brain", "extant cetacean"]}
{"id": "paleo.008832", "title": "A gigantic new dinosaur from Argentina and the evolution of the sauropod hind foot", "abstract": "Titanosauria is an exceptionally diverse, globally-distributed clade of sauropod dinosaurs that includes the largest known land animals. Knowledge of titanosaurian pedal structure is critical to understanding the stance and locomotion of these enormous herbivores and, by extension, gigantic terrestrial vertebrates as a whole. However, completely preserved pedes are extremely rare among Titanosauria, especially as regards the truly giant members of the group. Here we describe Notocolossus gonzalezparejasi gen. et sp. nov. from the Upper Cretaceous of Mendoza Province, Argentina. With a powerfully-constructed humerus 1.76 m in length, Notocolossus is one of the largest known dinosaurs. Furthermore, the complete pes of the new taxon exhibits a strikingly compact, homogeneous metatarsus\u2014seemingly adapted for bearing extraordinary weight\u2014and truncated unguals, morphologies that are otherwise unknown in Sauropoda. The pes underwent a near-progressive reduction in the number of phalanges along the line to derived titanosaurs, eventually resulting in the reduced hind foot of these sauropods.", "keyphrases": ["argentina", "sauropod", "hind foot", "notocolossus", "humerus"]}
{"id": "paleo.012503", "title": "Origin and Diversification of Major Clades in Parmelioid Lichens (Parmeliaceae, Ascomycota) during the Paleogene Inferred by Bayesian Analysis", "abstract": "There is a long-standing debate on the extent of vicariance and long-distance dispersal events to explain the current distribution of organisms, especially in those with small diaspores potentially prone to long-distance dispersal. Age estimates of clades play a crucial role in evaluating the impact of these processes. The aim of this study is to understand the evolutionary history of the largest clade of macrolichens, the parmelioid lichens (Parmeliaceae, Lecanoromycetes, Ascomycota) by dating the origin of the group and its major lineages. They have a worldwide distribution with centers of distribution in the Neo- and Paleotropics, and semi-arid subtropical regions of the Southern Hemisphere. Phylogenetic analyses were performed using DNA sequences of nuLSU and mtSSU rDNA, and the protein-coding RPB1 gene. The three DNA regions had different evolutionary rates: RPB1 gave a rate two to four times higher than nuLSU and mtSSU. Divergence times of the major clades were estimated with partitioned BEAST analyses allowing different rates for each DNA region and using a relaxed clock model. Three calibrations points were used to date the tree: an inferred age at the stem of Lecanoromycetes, and two dated fossils: Parmelia in the parmelioid group, and Alectoria. Palaeoclimatic conditions and the palaeogeological area cladogram were compared to the dated phylogeny of parmelioid. The parmelioid group diversified around the K/T boundary, and the major clades diverged during the Eocene and Oligocene. The radiation of the genera occurred through globally changing climatic condition of the early Oligocene, Miocene and early Pliocene. The estimated divergence times are consistent with long-distance dispersal events being the major factor to explain the biogeographical distribution patterns of Southern Hemisphere parmelioids, especially for Africa-Australia disjunctions, because the sequential break-up of Gondwana started much earlier than the origin of these clades. However, our data cannot reject vicariance to explain South America-Australia disjunctions.", "keyphrases": ["parmeliaceae", "ascomycota", "evolutionary history", "lecanoromycetes"]}
{"id": "10.3390/genes12060910", "title": "How a Paleogenomic Approach Can Provide Details on Bioarchaeological Reconstruction: A Case Study from the Globular Amphorae Culture", "abstract": "Ancient human remains have the potential to explain a great deal about the prehistory of humankind. Due to recent technological and bioinformatics advances, their study, at the palaeogenomic level, can provide important information about population dynamics, culture changes, and the lifestyles of our ancestors. In this study, mitochondrial and nuclear genome data obtained from human bone remains associated with the Neolithic Globular Amphorae culture, which were recovered in the Megalithic barrow of Kierzkowo (Poland), were reanalysed to gain insight into the social organisation and use of the archaeological site and to provide information at the individual level. We were able to successfully estimate the minimum number of individuals, sex, kin relationships, and phenotypic traits of the buried individuals, despite the low level of preservation of the bone samples and the intricate taphonomic conditions. In addition, the evaluation of damage patterns allowed us to highlight the presence of \u201cintruders\u201d\u2014that is, of more recent skeletal remains that did not belong to the original burial. Due to its characteristics, the study of the Kierzkowo barrow represented a challenge for the reconstruction of the biological profile of the human community who exploited it and an excellent example of the contribution that ancient genomic analysis can provide to archaeological reconstruction.", "keyphrases": ["case study", "human remain", "archaeological reconstruction"]}
{"id": "paleo.003132", "title": "Mesozoic and Tertiary Anura of Laurasia", "abstract": "Anurans of Laurasia have a long history that begins with the earliest known anuran, Prosalirus, from the Early Jurassic of Arizona, USA. At that time, western Laurasia (North America) was still connected with Gondwana, so faunal interchange was still possible between those parts of the former Pangean supercontinent. The anuran fossil record from the Jurassic and Cretaceous of Laurasia is mainly represented by disarticulated skeletal elements similar to those of Prosalirus (e.g. amphicoelous vertebrae indicating the presence of continuous notochord; ilia without dorsal crest and dorsal tubercle; small body size). Because the morphology of the ilium, the most commonly preserved element of Mesozoic anurans, superficially recalls that of Recent Alytes, Bombina or Pelobates , Mesozoic anurans often were assigned to discoglossids and pelobatids. The Cretaceous portion of the Laurasian anuran record is marked by the appearance of procoelous and opisthocoelous vertebrae, ilia bearing a dorsal crest and dorsal tubercle (although such ilia may rarely be found as early as in the Jurassic) and larger body sizes. Cretaceous anuran assemblages include a mix of generalised taxa that are comparable to Recent basal anurans and more specialised taxa lacking clear affinities with any extant anurans. Some of these forms survived into the Paleocene, but in general anuran faunas on all Laurasian continents were markedly depleted in the Paleocene. Major groups of anurans appeared in the Eocene. The early Miocene is the interval when Eurasian and American herpetofaunas reached their peak taxonomic diversities. In the Pliocene, some extant anuran species appeared, but at the same time taxa that had been dominant throughout the Oligocene and Miocene (e.g. Eopelobates , palaeobatrachids) became extinct during this interval or during the subsequent Pleistocene glaciation. The brief biochronological synopsis presented here is followed by a systematic review of taxa with their diagnoses and published data on their stratigraphic and geographic distributions.", "keyphrases": ["laurasia", "north america", "miocene", "europe", "ontogenetic series"]}
{"id": "10.1126/science.1129569", "title": "Decoupled Plant and Insect Diversity After the End-Cretaceous Extinction", "abstract": "Food web recovery from mass extinction is poorly understood. We analyzed insect-feeding damage on 14,999 angiosperm leaves from 14 latest Cretaceous, Paleocene, and early Eocene sites in the western interior United States. Most Paleocene floras have low richness of plants and of insect damage. However, a low-diversity 64.4-million-year-old flora from southeastern Montana shows extremely high insect damage richness, especially of leaf mining, whereas an anomalously diverse 63.8-million-year-old flora from the Denver Basin shows little damage and virtually no specialized feeding. These findings reveal severely unbalanced food webs 1 to 2 million years after the end-Cretaceous extinction 65.5 million years ago.", "keyphrases": ["end-cretaceous extinction", "damage", "leave"]}
{"id": "10.5194/cp-17-269-2021", "title": "The Eocene\u2013Oligocene transition: a review of marine and terrestrial proxy data, models and model\u2013data comparisons", "abstract": "Abstract. The Eocene-Oligocene transition (EOT) from a largely ice-free greenhouse world to an icehouse climate with the first major glaciation of Antarctica was a phase of major climate and environmental change occurring ~34 million years ago (Ma) and lasting ~500\u2009kyr. The change is marked by a global shift in deep sea \u03b418O representing a combination of deep-ocean cooling and global ice sheet growth. At the same time, multiple independent proxies for sea surface temperature indicate a surface ocean cooling, and major changes in global fauna and flora record a shift toward more cold-climate adapted species. The major explanations of this transition that have been suggested are a decline in atmospheric CO2, and changes to ocean gateways, while orbital forcing likely influenced the precise timing of the glaciation. This work reviews and synthesises proxy evidence of paleogeography, temperature, ice sheets, ocean circulation, and CO2 change from the marine and terrestrial realms. Furthermore, we quantitatively compare proxy records of change to an ensemble of model simulations of temperature change across the EOT. The model simulations compare three forcing mechanisms across the EOT: CO2 decrease, paleogeographic changes, and ice sheet growth. We find that CO2 forcing provides by far the best explanation of the combined proxy evidence, and based on our model ensemble, we estimate that a CO2 decrease of about 1.6\u00d7 across the EOT (e.g. from 910 to 560 \u2009ppmv) achieves the best fit to the temperature change recorded in the proxies. This model-derived CO2 decrease is consistent with proxy estimates of CO2 decline at the EOT.", "keyphrases": ["proxy data", "eot", "antarctica", "cooling", "major change"]}
{"id": "10.1051/bsgf/2019012", "title": "The complete lithostratigraphic section of the geothermal wells in Rittershoffen (Upper Rhine Graben, eastern France): a key for future geothermal wells", "abstract": "Between 2012 and 2014, in Rittershoffen, in the Upper Rhine Graben, two geothermal boreholes (GRT-1 and GRT-2) reached the granitic basement at a depth of around 2150\u2009m. The wells crossed about 1160\u2009m of Cenozoic and 1050\u2009m of Mesozoic. In the Cenozoic, these wells crossed the greatest part of the Eocene, the lower part of the Oligocene and a thinner Pliocene. The Quaternary is poorly represented (less than 10\u2009m). In the Mesozoic, the wells crossed the Lower Dogger, the entire Lias and the entire Triassic. A reduced thickness of about 50\u2009m of Upper Permian terminates the sedimentary column before entering into the granitic basement. A major erosional unconformity separates the Middle Jurassic from the Tertiary units (the Upper Jurassic, entire Cretaceous and Paleocene are absent). The Rittershoffen drilled doublets were the subject of particular attention concerning the acquisition of a very precise stratigraphic profile. In this paper, we give the recognition criteria for the fifty-seven formations crossed by the GRT-1 well and their upper and lower boundaries as well as their specific gamma ray signatures. The data are presented in four figures: a general complete log displaying the main sets and three detailed, precise logs showing the sedimentary formations overhanging the granitic basement: the Tertiary, the Jurassic, the Triassic, the Permian and the basement.", "keyphrases": ["geothermal borehole", "granite", "mesozoic sedimentary succession", "paleozoic", "landau"]}
{"id": "paleo.012368", "title": "A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology", "abstract": "Azhdarchid pterosaurs were among the most widespread and successful of pterosaur clades, but their paleoecology remains controversial. Morphological features common to all azhdarchids include a long, shallow rostrum; elongate, cylindrical cervical vertebrae that formed a long and unusually inflexible neck; and proportionally short wings with an abbreviated fourth phalanx. While azhdarchids have been imagined as vulture-like scavengers, sediment probers, swimmers, waders, aerial predators, or stork-like generalists, most recent authors have regarded them as skim-feeders, trawling their lower jaws through water during flight and seizing aquatic prey from the water's surface. Although apparently widely accepted, the skim-feeding model lacks critical support from anatomy and functional morphology. Azhdarchids lack the many cranial specialisations exhibited by extant skim-feeding birds, most notably the laterally compressed lower jaw and shock absorbing apparatus required for this feeding style. Well-preserved azhdarchid skulls are rare, but their rostra and lower jaws appear to have been sub-triangular in cross-section, and thus dissimilar to those of skim-feeders and sediment probers. Taphonomic data indicates that azhdarchids predominately inhabited inland settings, and azhdarchid morphology indicates that they were poorly suited for all proposed lifestyles bar wading and terrestrial foraging. However, azhdarchid footprints show that their feet were relatively small, padded and slender, and thus not well suited for wading. We argue that azhdarchids were stork- or ground hornbill-like generalists, foraging in diverse environments for small animals and carrion. Proficient terrestrial abilities and a relatively inflexible neck are in agreement with this interpretation.", "keyphrases": ["azhdarchid", "morphology", "paleoecology", "vertebrae", "low jaw"]}
{"id": "paleo.000876", "title": "THE ENIGMATIC EARLY CAMBRIAN SALANYGOLINA\u2013 A STEM GROUP OF RHYNCHONELLIFORM CHILEATE BRACHIOPODS?", "abstract": "Abstract:\u2002 New material of the enigmatic brachiopod Salanygolina obliqua Ushatinskaya from the Early Cambrian of Mongolia shows that it has a colleplax\u2013 a triangular plate \u2013 in the umbonal perforation, which is enlarged by resorption. This structure is otherwise only known from the equally enigmatic Palaeozoic orders Chileida and Dictyonellida (Rhynchonelliformea, Chileata). The colleplax in Salanygolina is here considered to be homologous with that of the chileates. Salanygolina is also provided with a ridge\u2010like pseudodeltidium, which is another chileate feature. Other characters of Salanygolina, like the radial arrangement of adductor muscle scars and postero\u2010medially placed internal oblique muscles are characteristic of chileates, but also found in the paterinates. In contrast, mixoperipheral dorsal valves with low rudimentary interareas are well known in paterinates, but not yet recorded from chileates. Thus, Salanygolina shows a mosaic combination of morphologic characters, known both from the paterinates and chileates, indicating that it may represent a stem group of the rhynchonelliform chileate brachiopods. The laminar phosphatic secondary shell of Salanygolina is composed of closely packed and nearly identical hexagonal prisms, oriented with their long axis normal to the laminae in a honeycomb pattern. The prism walls appear to have originally been composed of organic membranes and might represent precursors of the organic sheaths of calcite fibers that are typical of calcitic shells with a fibrous microstructure.", "keyphrases": ["salanygolina", "stem group", "hexagonal prism", "laminae"]}
{"id": "10.1130/g22460.1", "title": "New method to estimate paleoprecipitation using fossil amphibians and reptiles and the middle and late Miocene precipitation gradients in Europe", "abstract": "Existing methods for determining paleoprecipitation are subject to large errors (6350- 400 mm or more using mammalian proxies), or are restricted to wet climate systems due to their strong facies dependence (paleobotanical proxies). Here we describe a new paleo- precipitation tool based on an indexing of ecophysiological groups within herpetological communities. In recent communities these indices show a highly significant correlation to annual precipitation (r 2 5 0.88), and yield paleoprecipitation estimates with average errors of 6250-280 mm. The approach was validated by comparison with published paleopre- cipitation estimates from other methods. The method expands the application of paleo- precipitation tools to dry climate systems and in this way contributes to the establishment of a more comprehensive paleoprecipitation database. This method is applied to two high- resolution time intervals from the European Neogene: the early middle Miocene (early Langhian) and the early late Miocene (early Tortonian). The results indicate that both periods show significant meridional precipitation gradients in Europe, these being stronger in the early Langhian (threefold decrease toward the south) than in the early Tortonian (twofold decrease toward the south). This pattern indicates a strengthening of climatic belts during the middle Miocene climatic optimum due to Southern Hemisphere cooling and an increased contribution of Arctic low-pressure cells to the precipitation from the late Miocene onward due to Northern Hemisphere cooling.", "keyphrases": ["paleoprecipitation", "europe", "annual precipitation"]}
{"id": "10.1073/pnas.1003220107", "title": "Polar front shift and atmospheric CO2 during the glacial maximum of the Early Paleozoic Icehouse", "abstract": "Our new data address the paradox of Late Ordovician glaciation under supposedly high pCO2 (8 to 22\u00d7 PAL: preindustrial atmospheric level). The paleobiogeographical distribution of chitinozoan (\u201cmixed layer\u201d) marine zooplankton biotopes for the Hirnantian glacial maximum (440 Ma) are reconstructed and compared to those from the Sandbian (460 Ma): They demonstrate a steeper latitudinal temperature gradient and an equatorwards shift of the Polar Front through time from 55\u00b0\u201370\u00b0 S to \u223c40\u00b0 S. These changes are comparable to those during Pleistocene interglacial-glacial cycles. In comparison with the Pleistocene, we hypothesize a significant decline in mean global temperature from the Sandbian to Hirnantian, proportional with a fall in pCO2 from a modeled Sandbian level of \u223c8\u00d7 PAL to \u223c5\u00d7 PAL during the Hirnantian. Our data suggest that a compression of midlatitudinal biotopes and ecospace in response to the developing glaciation was a likely cause of the end-Ordovician mass extinction.", "keyphrases": ["glacial maximum", "latitudinal temperature gradient", "polar front"]}
{"id": "paleo.012081", "title": "Cope's Rule in a modular organism: Directional evolution without an overarching macroevolutionary trend", "abstract": "Cope's Rule describes increasing body size in evolutionary lineages through geological time. This pattern has been documented in unitary organisms but does it also apply to module size in colonial organisms? We address this question using 1169 cheilostome bryozoans ranging through the entire 150 million years of their evolutionary history. The temporal pattern evident in cheilostomes as a whole shows no overall change in zooid (module) size. However, individual subclades show size increases: within a genus, younger species often have larger zooids than older species. Analyses of (paleo)latitudinal shifts show that this pattern cannot be explained by latitudinal effects (Bergmann's Rule) coupled with younger species occupying higher latitudes than older species (an \u201cout of the tropics\u201d hypothesis). While it is plausible that size increase was linked to the advantages of large zooids in feeding, competition for trophic resources and living space, other proposed mechanisms for Cope's Rule in unitary organisms are either inapplicable to cheilostome zooid size or cannot be evaluated. Patterns and mechanisms in colonial organisms cannot and should not be extrapolated from the better\u2010studied unitary organisms. And even if macroevolution simply comprises repeated rounds of microevolution, evolutionary processes occurring within lineages are not always detectable from macroevolutionary patterns.", "keyphrases": ["cheilostome bryozoan", "evolutionary history", "zooid", "cope"]}
{"id": "10.1080/02724634.1993.10011487", "title": "The laterosphenoid bone of early archosauriforms", "abstract": "ABSTRACT The laterosphenoid is an ossification of the pila antotica neurocranial cartilage in the anterior sidewall of the braincase of crocodylians and birds. Contrary to published reports, the bone is present in the basal archosauriforms Proterosuchus fergusi, Euparkeria capensis, and Erythrosuchidae, taxa that diverged prior to the origin of the archosaurian crown group. Its presence is thus a synapomorphy of Archosauriformes rather than of Archosauria. The bone appears to have been induced by shifting jaw muscle origins from the skull roof to the anterolateral wall of the braincase. Additional innovations in the archosauriform feeding apparatus, such as a mandibular fenestra, appear to reflect changes in jaw muscles that may, in turn, facilitate predaceous habits. We review the historical development of the names of bones in the anterior sidewall of the amniote braincase and argue for the use of the term laterosphenoid, rather than either pleurosphenoid or orbitosphenoid, for this bone in all Archosau...", "keyphrases": ["laterosphenoid", "archosauriformes", "ossification", "pila antotica"]}
{"id": "paleo.001292", "title": "The Euro-American genus Eopelobates, and a re-definition of the family Pelobatidae (Amphibia, Anura)", "abstract": "The extinct Eopelobates (Eocene of western North America; Eocene-Pliocene of Europe) and Pelobates (Oligocene-Recent of Europe; Recent of northern Africa and the Middle East) are superficially toad-like anurans that are united within the family Pelobatidae mainly on the basis of a unique, tripartite frontoparietal complex. Both genera have a relatively good fossil record consisting of isolated bones, skeletons, and developmental series of tadpoles through adults, all of which are potentially informative for tracing the evolutionary history of the family. Eopelobates is of interest for several reasons. Of the two pelobatid genera, Eopelobates appears earlier in the fossil record (early Eocene vs. late Oligocene) and it is more primitive in lacking many of the features associated with fossoriality in extant Pelobates. The taxonomic composition of Eopelobates has been contentious and at least one putative new species has long been recognised, but never formally named. Here, we provide updated taxonomic accounts for Pelobatoidea, Pelobatidae, Pelobates, and Eopelobates and document development within a series of tadpoles and juveniles of E. bayeri from Bechlejovice (late Oligocene in age), Czech Republic. We also provide updated accounts for the five previously named and currently accepted species of Eopelobates. For the European congeners, E. anthracinus (late Oligocene) and E. bayeri (early Oligocene-middle Miocene) can confidently be regarded as separate species; although the distinction between E. hinschei and E. wagneri (both middle Eocene) is less certain, we provisionally maintain them as separate species. Micro-CT scans for the holotype skeleton of E. grandis (latest Eocene, USA) help resolve some problematic features, most notably showing that the cranial sculpture is of the pit-and-ridge style that is typical for Eopelobates. A sixth congener is named and described based on two skeletons from the middle Eocene portion of the Green River Formation, in Wyoming, USA. We caution that reports of Eopelobates-like anurans from the pre-Eocene of western North America and the early Eocene of India are based on isolated bones that cannot be assigned with confidence to that genus. The presence of Eopelobates in both North America and Europe may be explained by dispersal via the high latitude land bridge that connected those two continents during the late Paleocene through Eocene. The pelobatid fossil record is informative for documenting the nature and timing of changes in cranial features (e.g. ornament patterns, shape of nasals, pattern of frontoparietal-squamosal contact) from the inferred primitive condition seen in most Eopelobates to the more derived condition seen in extant Pelobates, but it is less informative for tracing the evolution of fossoriality, which is a key attribute of extant Pelobates.", "keyphrases": ["family pelobatidae", "north america", "pelobates", "oligocene"]}
{"id": "paleo.005652", "title": "New Information on the Pterosaur Tupandactylus imperator, with Comments on the Relationships of Tapejaridae", "abstract": "A new specimen of Tupandactylus imperator, comprising an incomplete skull with associated lower jaw, is described. The material is the best preserved specimen of this species known so far and provides new information on the anatomy of this pterodactyloid pterosaur, especially with respect to the morphology of the lower jaw, the first one formally described for the species. Also, the new specimen shows an extensive preservation of soft tissues such as the soft-tissue component of the headcrest, ramphoteca associated with the premaxillae and lower jaw, as well as probable pycnofibres. A phylogenetic analysis was performed in order to test the relationships of the taxon within Tapejaridae. The results of the analysis support Tapejaridae, as well as monophyly of Tapejarinae and Thalassodrominae.", "keyphrases": ["tapejaridae", "skull", "respect", "new information"]}
{"id": "10.1080/14772019.2015.1042080", "title": "Diverse new Middle Jurassic Osmylopsychopidae (Neuroptera) from China shed light on the classification of psychopsoids", "abstract": "A well-preserved diverse fauna of fossil neuropterans of the family Osmylopsychopidae has been discovered at the Middle Jurassic locality of Daohugou, China. Daopsychops dissectus gen. et sp. nov., D. clausus gen. et sp. nov., D. inanis gen. et sp. nov., D. bifasciatus gen. et sp. nov., D. cubitalis gen. et sp. nov., Eupypsychops ferox gen. et sp. nov., E. confinis gen. et sp. nov., Nematopsychops unicus gen. et sp. nov., Ochropsychops multus gen. et sp. nov. and Stenopteropsychops trifasciatus gen. et sp. nov. are described. These new taxa allow a better understanding of the relationships between the psychopsoid families Osmylopsychopidae, Psychopsidae and Brongniartiellidae. The type of the latter (Brongniartiella gigas from the Late Jurassic of Germany) is redescribed. The venation of the new genera of Osmylopsychopidae shows that Brongniartiellidae is a synonym of this family. Of the genera ascribed to Brongniartiellidae, only Pseudopsychopsis belongs to Osmylopsychopidae with certainty. Gigantopsychops reticulatus gen. et sp. nov. from Daohugou (Psychopsidae) is an important taxon providing a new insight into the definition of the family. Wings of Psychopsidae may be distinguished from those of Osmylopsychopidae by a combination of the following character states: in both wings, the costal space is very broad distally; Rs1 is not deeply forked; the distal nygma is lost; the distal R1 is straight, not curved posteriad; in the hind wing, 1r-m is short and straight. It is clear now that the family Osmylopsychopidae was a dominant psychopsoid group during the Mesozoic, and Psychopsidae was relatively rare. http://zoobank.org/urn:lsid:zoobank.org:pub:E3E3F401-747F-427B-A46C-51B4148A5D0D", "keyphrases": ["osmylopsychopidae", "china", "psychopsidae"]}
{"id": "paleo.006947", "title": "THE FOSSIL RECORD AND EVOLUTION OF MOUSEBIRDS (AVES: COLIIFORMES)", "abstract": "Abstract:\u2002 Recent mousebirds are the smallest of the living neognathous bird orders \u2013 just two genera comprising six species. Understanding the evolutionary dynamics of this avian lineage is important because these birds occupy a critical position within Neoaves and can be used as a model for patterns of morphological diversification in other taxa. We present a review of all known fossil mousebirds (Aves: Coliiformes), which formed a diverse assemblage in the Paleogene (65\u201323.8\u2003ma). We also present a new phylogenetic analysis including the living and fossil representatives of the order, on the basis of a larger character/taxon matrix. This analysis suggests that the Lower Eocene Eocolius is the most basal member of clade Coliiformes, while the Lower\u2013Middle Eocene Sandcoleidae form a basal clade with respect to all other known coliiforms. We show that the Eocene taxon Chascacocolius is the sister group of the crown Coliidae, and that the Middle Eocene taxon Selmes is basal to a clade comprising Chascacocolius and Coliidae. On the basis of this phylogenetic analysis, we propose a new classification for the order Coliiformes including two new families, Chascacocoliidae and Selmeidae. For all families (clades) of mousebirds we provide descriptive osteological diagnoses and discuss a number of functional considerations related to the evolution of their hindlimbs; these considerations can be extended across all extant and fossil perching birds because we show that the hindlimb morphology of Coliiformes is strongly related to their lifestyle, as reflected in their evolutionary history.", "keyphrases": ["mousebird", "coliiformes", "chascacocolius"]}
{"id": "10.7717/peerj.5964", "title": "Comparative cranial morphology of the Late Cretaceous protostegid sea turtle Desmatochelys lowii", "abstract": "Background The phylogenetic placement of Cretaceous marine turtles, especially Protostegidae, is still under debate among paleontologists. Whereas protostegids were traditionally thought to be situated within the clade of recent marine turtles (Chelonioidea), some recent morphological and molecular studies suggest placement along the stem of Cryptodira. The main reason why the evolution of marine turtles is still poorly understood, is in part due to a lack of insights into the cranial anatomy of protostegids. However, a general availability of high-quality fossil material, combined with modern analysis techniques, such as X-ray microtomography, provide ample opportunity to improve this situation. The scope of this study is to help resolve its phylogenetic relationships by providing a detailed description of the external and internal cranial morphology of the extinct protostegid sea turtle Desmatochelys lowii Williston, 1894. Material and Methods This study is based on the well-preserved holotype of Desmatochelys lowii from the Late Cretaceous (middle Cenomanian to early Turonian) Greenhorn Limestone of Jefferson County, Nebraska. The skulls of two recent marine turtles, Eretmochelys imbricata (Linnaeus, 1766) (Cheloniidae) and Dermochelys coriacea Lydekker, 1889 (Dermochelyidae), as well as the snapping turtle Chelydra serpentina (Linnaeus, 1758) (Chelydridae) provide a comparative basis. All skulls were scanned using regular or micro CT scanners and the scans were then processed with the software program Amira to create 3D isosurface models. In total, 81 bones are virtually isolated, figured, and described, including the nature of their contacts. The novel bone contact data is compiled and utilized in a preliminary phenetic study. In addition, an update phylogenetic analysis is conduced that utilizes newly obtained anatomical insights. Results The detailed examination of the morphology of the herein used specimens allowed to explore some features of the skull, to refine the scoring of Desmatochelys lowii in the recent global matrix of turtles, and develop five new characters. The alleged pineal foramen in the type skull of Desmatochelys lowii is shown to be the result of damage. Instead, it appears that the pineal gland only approached the skull surface, as it is in Dermochelys coriacea. Whereas the parasphenoid in confirmed to be absent in hard-shelled sea turtles, ist possible presence in Desmatochelys lowii is unclear. The results of the phenetic study show that Desmatochelys lowii is least similar to the other examined taxa in regards to the nature of its bone contacts, and therefore suggests a placement outside Americhelydia for this protostegid sea turtle. The phylogenetic study results in a placement of Protostegidae along the stem of Chelonioidea, which is a novel position for the group.", "keyphrases": ["cranial morphology", "turtle", "protostegidae", "cheloniidae"]}
{"id": "10.5194/gmd-11-2563-2018", "title": "Comparison of spatial downscaling methods of general circulation model results to study climate variability during the Last Glacial Maximum", "abstract": "Abstract. The extent to which climate conditions influenced the spatial\ndistribution of hominin populations in the past is highly debated.\nGeneral circulation models (GCMs) and archaeological data have been\nused to address this issue. Most GCMs are not currently capable of\nsimulating past surface climate conditions with sufficiently\ndetailed spatial resolution to distinguish areas of potential\nhominin habitat, however. In this paper, we propose a statistical\ndownscaling method (SDM) for increasing the resolution of climate\nmodel outputs in a computationally efficient way. Our method uses a\ngeneralised additive model (GAM), calibrated over present-day\nclimatology data, to statistically downscale temperature and\nprecipitation time series from the outputs of a GCM simulating the\nclimate of the Last Glacial Maximum (19\u2009000\u201323\u2009000\u2009BP) over western\nEurope. Once the SDM is calibrated, we first interpolate the\ncoarse-scale GCM outputs to the final resolution and then use the\nGAM to compute surface air temperature and precipitation levels\nusing these interpolated GCM outputs and fine-resolution\ngeographical variables such as topography and distance from an\nocean. The GAM acts as a transfer function, capturing non-linear\nrelationships between variables at different spatial scales and\ncorrecting for the GCM biases. We tested three different techniques\nfor the first interpolation of GCM output: bilinear, bicubic and\nkriging. The resulting SDMs were evaluated by comparing downscaled\ntemperature and precipitation at local sites with paleoclimate\nreconstructions based on paleoclimate archives (archaeozoological\nand palynological data) and the impact of the interpolation\ntechnique on patterns of variability was explored. The SDM based on\nkriging interpolation, providing the best accuracy, was then\nvalidated on present-day data outside of the calibration period. Our\nresults show that the downscaled temperature and precipitation\nvalues are in good agreement with paleoclimate reconstructions at\nlocal sites, and that our method for producing fine-grained\npaleoclimate simulations is therefore suitable for conducting\npaleo-anthropological research. It is nonetheless important to\ncalibrate the GAM on a range of data encompassing the data to be\ndownscaled. Otherwise, the SDM is likely to overcorrect the\ncoarse-grain data. In addition, the bilinear and bicubic\ninterpolation techniques were shown to distort either the temporal\nvariability or the values of the response variables, while the\nkriging method offered the best compromise. Since climate\nvariability is an aspect of the environment to which human\npopulations may have responded in the past, the choice of\ninterpolation technique is therefore an important consideration.\n", "keyphrases": ["glacial maximum", "climate condition", "topography", "spatial scale"]}
{"id": "10.1146/annurev-ento-120710-100538", "title": "Advances in insect phylogeny at the dawn of the postgenomic era.", "abstract": "Most species on Earth are insects and thus, understanding their evolutionary relationships is key to understanding the evolution of life. Insect relationships are increasingly well supported, due largely to technological advances in molecular sequencing and phylogenetic computational analysis. In this postgenomic era, insect systematics will be furthered best by integrative methods aimed at hypothesis corroboration from molecular, morphological, and paleontological evidence. This review of the current consensus of insect relationships provides a foundation for comparative study and offers a framework to evaluate incoming genomic evidence. Notable recent phylogenetic successes include the resolution of Holometabola, including the identification of the enigmatic Strepsiptera as a beetle relative and the early divergence of Hymenoptera; the recognition of hexapods as a crustacean lineage within Pancrustacea; and the elucidation of Dictyoptera orders, with termites placed as social cockroaches. Regions of the tree that require further investigation include the earliest winged insects (Palaeoptera) and Polyneoptera (orthopteroid lineages).", "keyphrases": ["postgenomic era", "cockroach", "advance"]}
{"id": "10.1046/j.1365-2583.1997.00175.x", "title": "Mitochondrial haplotypes and phylogeography of Phlebotomus vectors of Leishmania major", "abstract": "Haplotypes of eight phlebotomine species were characterized by cycle sequencing a mitochondrial (mt) DNA fragment (cytochrome b to NADH1) amplified from single sandflies by PCR. Phlebotomus (Phlebotomus) papatasi displayed little variation throughout its large geographical range. We conclude that this vector of Leishmania major suffered a population bottleneck late in the Pleistocene and then radiated out from the eastern Mediterranean subregion. There was no support for a recent domestic lineage of P. papatasi. The mtDNA molecular clock in phlebotomines (subgenera Phlebotomus and Larroussius) was calibrated by reference to palaeogeographical events in Africa and the Mediterranean subregion. It fitted a pairwise nucleotide sequence divergence rate of 1.0\u20132.5% per million years. Co\u2010evolution of L. major, its Phlebotomus vectors and mammalian reservoirs is discussed.", "keyphrases": ["phlebotomus vector", "leishmania major", "mediterranean sandfly fauna", "miocene diversification", "speciation"]}
{"id": "10.1666/13-038", "title": "A Complete Reconstruction of the Hyolithid Skeleton", "abstract": "Abstract Hyolithids are a group of Paleozoic lophotrochozoans with a four-pieced skeleton consisting of a conch, an operculum, and a pair of lateral \u2018spines' named helens. Both the conch and operculum are relatively well known and, to a certain extent, have modern analogues in other lophotrochozoan groups. The helens, on the other hand, are less well known and do not have clear modern analogues. This has hindered the knowledge of the complete morphology of the hyolithid skeleton, as well as other aspects of hyolithid biology, such as the organization of soft parts, and their ability to move. The material studied herein, consisting of disarticulated skeletal elements from the Silurian of Gotland, Sweden, illustrates a complete developmental sequence of a hyolithid species and includes the first complete, three-dimensionally preserved helens. Our material confirms that helens were massive skeletal elements, whose growth started proximally with the deposition of a central, coherent lamella. Further shell accretion took place around this lamella, but followed a particular accretion pattern probably constrained by the presence of marginal muscle attachment sites on the proximal-most portion of the helens. These muscle attachment sites were ideally located to allow a wide range of movements for the helens, suggesting that hyolithids may have been relatively mobile organisms.", "keyphrases": ["hyolithid skeleton", "conch", "operculum", "pair", "spine"]}
{"id": "10.1130/G31879.1", "title": "Infaunal molting in Trilobita and escalatory responses against predation", "abstract": "The outstanding fossil record of trilobites contrasts with our limited knowledge of their lifestyles and strategies. Aspects such as infaunalism and behavioral defensive skills in this group have yet to be demonstrated conclusively. We report new insights based on a striking sclerite configuration exhibited by three phacopid trilobite species, part of a late Silurian\u2013Early Devonian Paciphacops ( Paciphacops ) Maksimova, 1972, lineage. An unusual molt pattern provides compelling evidence of infaunal behavior, which accounts for a hiding, antipredatory adaptation. In addition, strengthening of the exoskeleton and acquisition of spines indicate an evolutionary trend toward morphological defensive strategies. Both trends in active and passive traits are considered escalatory in nature, thus providing unequivocal support for understanding the ecological role of trilobites as a main prey group in the context of the global diversification of predators recorded during middle Paleozoic time.", "keyphrases": ["predation", "trilobite moulting", "environment"]}
{"id": "10.1111/j.1096-0031.2008.00226.x", "title": "Phylogeny of the great cats (Felidae: Pantherinae), and the influence of fossil taxa and missing characters", "abstract": "Molecular phylogenetic studies of the extant Pantherinae have resulted in a variety of different hypotheses of relationships. This study presents the results of a cladistic study encompassing 45 osteological and dental characters in the skull and mandible, as well as 13 soft\u2010tissue and behavioural characters. Analyzing extant pantherines with osteological data only resulted in two equally parsimonious trees, which differed only with respects to the jaguar, a taxon which shows morphological affinity to the tiger as well as the lion\u2003+\u2003leopard. Addition of soft\u2010tissue characters resolved this ambiguity, and led to markedly improved bootstrap values. The inclusion of fossil taxa did not have an impact on topology, but was important for a correct understanding of character evolution, due to the fossils having a combination of characters unlike those of any extant taxon. The clouded leopard is the most basal pantherine, followed by the snow leopard. The large pantherines are a well supported group, to which the snow leopard does not belong, contrary to some molecular studies. Panthera palaeosinensis is no tiger, but may be close to the stem group from which the tiger evolved. P. atrox and P. spelaea are not on the lion lineage, as traditionally assumed, but are successive outgroups to the lion\u2003+\u2003leopard, although the position of P. spelaea is tentative, but is supported by other lines of evidence such as brain anatomy.", "keyphrases": ["pantherinae", "fossil taxa", "lion", "leopard", "outgroup"]}
{"id": "paleo.010944", "title": "Pluridisciplinary evidence for burial for the La Ferrassie 8 Neandertal child", "abstract": "The origin of funerary practices has important implications for the emergence of so-called modern cognitive capacities and behaviour. We provide new multidisciplinary information on the archaeological context of the La Ferrassie 8 Neandertal skeleton (grand abri of La Ferrassie, Dordogne, France), including geochronological data -14C and OSL-, ZooMS and ancient DNA data, geological and stratigraphic information from the surrounding context, complete taphonomic study of the skeleton and associated remains, spatial information from the 1968\u20131973 excavations, and new (2014) fieldwork data. Our results show that a pit was dug in a sterile sediment layer and the corpse of a two-year-old child was laid there. A hominin bone from this context, identified through Zooarchaeology by Mass Spectrometry (ZooMS) and associated with Neandertal based on its mitochondrial DNA, yielded a direct 14C age of 41.7\u201340.8 ka cal BP (95%), younger than the 14C dates of the overlying archaeopaleontological layers and the OSL age of the surrounding sediment. This age makes the bone one of the most recent directly dated Neandertals. It is consistent with the age range for the Ch\u00e2telperronian in the site and in this region and represents the third association of Neandertal taxa to Initial Upper Palaeolithic lithic technocomplex in Western Europe. A detailed multidisciplinary approach, as presented here, is essential to advance understanding of Neandertal behavior, including funerary practices.", "keyphrases": ["burial", "child", "archaeological context", "dna data", "western europe"]}
{"id": "paleo.000930", "title": "Autochthonous to parautochthonous bivalve concentrations within transgressive marginal marine strata of the Upper Jurassic of Portugal", "abstract": "Bivalve concentrations are a conspicuous feature of the Upper Jurassic rock succession of the central Lusitanian Basin. In order to illustrate the mode of their formation and their palaeoecological and sequence stratigraphic significance, we describe and interpret in detail 27 assemblages of bivalves based on their taphonomic and ecological features. Bivalve concentrations are particularly widespread in marginally marine, salinity-controlled environments and less common in open shelf settings. Only the Eomiodon and Myophorella concentrations are dominated by a shallow infaunal bivalve; all other concentrations are composed mainly of epi-or endobyssate [Isognomon (Rostroperna), I. (Isognomon), Pteria, Alaperna, Juranomia] and cementing taxa (Praeexogyra, Actinostreon). Most of the concentrations are mono-to paucispecific, except for the highly diverse Alaperna polita-Pteria credneriana concentrations, which occur in nearshore shelf environments. Lack of sorting, a high percentage of articulated shells, and shells preserved in growth position are evidence that, with few exceptions, the concentrations are autochthonous. Main factors leading to their formation are, apart from a gregarious life habit, a high productivity and a reduced rate of sedimentation. Autogenic and allogenic successional stages can be recognized on the basis of their spatial separation. The time involved in the formation of the concentrations is generally in the order of 10 2 -10 3 years. Due to the lack of compositional changes within concentrations, time-averaging played no or only a minor role, except in the Alaperna polita-Pteria credneriana concentrations. In sequence stratigraphic terms, most of the concentrations are the product of the maximum flooding zone, but in some cases they constitute the transgressive systems tract. Invariably, they are useful tools for defining depositional sequences. Several of the concentrations described here are not restricted to the Lusitanian Basin but also occur elsewhere in the epicontinental seas bordering the northern margin of the Neotethys.", "keyphrases": ["bivalve concentration", "benthic faunal association", "palaeoenvironment", "late jurassic unit"]}
{"id": "10.1525/aa.1999.101.2.322", "title": "The Big Deal about Blades: Laminar Technologies and Human Evolution", "abstract": "Despite the rapid expansion of archaeological knowledge of the Paleolithic over the past several decades, some generalized interpretive frameworks inherited from previous generations of researchers are remarkably tenacious. One of the most persistent of these is the assumed correlation between blade technologies, Upper Paleolithic industries, and anatomically (and behaviorally) modern humans. In this paper, we review some of the evidence for the production of early blade technologies in Eurasia and Africa dating to the late Lower and the Middle Paleolithic. The basic techniques for blade production appeared thousands of years before the Upper Paleolithic, and there is no justification for linking blades per se to any particular aspect of hominid anatomy or to any major change in the behavioral capacities of hominids. It is true that blades came to dominate the archaeological records of western Eurasia and Africa after 40,000 years ago, perhaps as a consequence of increasing reliance on complex composite tools during the Upper Paleolithic. At the same time, evidence from other regions of the world demonstrates that evolutionary trends in Pleistocene Eurasia were historically contingent and not universal. [Middle Paleolithic, Upper Paleolithic, blade technology, human evolution, hominid behavior and capacities]", "keyphrases": ["human evolution", "production", "eurasia"]}
{"id": "paleo.006843", "title": "A standard protocol for documenting modern and fossil ichnological data", "abstract": "The collection and dissemination of vertebrate ichnological data is struggling to keep up with techniques that are becoming commonplace in the wider palaeontological field. A standard protocol is required to ensure that data is recorded, presented and archived in a manner that will be useful both to contemporary researchers, and to future generations. Primarily, our aim is to make the 3D capture of ichnological data standard practice, and to provide guidance on how such 3D data can be communicated effectively (both via the literature and other means) and archived openly and in perpetuity. We recommend capture of 3D data, and the presentation of said data in the form of photographs, false\u2010colour images, and interpretive drawings. Raw data (3D models of traces) should always be provided in a form usable by other researchers (i.e. in an open format). If adopted by the field as a whole, the result will be a more robust and uniform literature, supplemented by unparalleled availability of datasets for future workers.", "keyphrases": ["standard protocol", "ichnological data", "researcher", "recommendation", "photogrammetric mesh"]}
{"id": "10.1002/ajb2.1187", "title": "Early Miocene CO2 estimates from a Neotropical fossil leaf assemblage exceed 400 ppm.", "abstract": "PREMISE OF THE STUDY\nThe global climate during the early Miocene was warmer than the present and preceded the even warmer middle Miocene climatic optimum. The paleo-CO2 records for this interval suggest paradoxically low concentrations (<450 ppm) that are difficult to reconcile with a warmer-than-present global climate.\n\n\nMETHODS\nIn this study, we use a leaf gas-exchange model to estimate CO2 concentrations using stomatal characteristics of fossil leaves from a late early Miocene Neotropical assemblage from Panama that we date to 18.01 \u00b1 0.17 Ma via 238 U/206 Pb zircon geochronology. We first validated the model for Neotropical environments by estimating CO2 from canopy leaves of 21 extant species in a natural Panamanian forest and from leaves of seven Neotropical species in greenhouse experiments at 400 and 700 ppm.\n\n\nKEY RESULTS\nThe results showed that the most probable combined CO2 estimate from the natural forests and 400 ppm experiments is 475 ppm, and for the 700 ppm experiments is 665 ppm. CO2 estimates from the five fossil species exhibit bimodality, with two species most consistent with a low mode (528 ppm) and three with a high mode (912 ppm).\n\n\nCONCLUSIONS\nDespite uncertainties, it is very likely (at >95% confidence) that CO2 during the late early Miocene exceeded 400 ppm. These results revise upwards the likely CO2 concentration at this time, more in keeping with a CO2 -forced greenhouse climate.", "keyphrases": ["leaf", "ppm", "gas-exchange model"]}
{"id": "10.1126/science.249.4965.154", "title": "Hind Limbs of Eocene Basilosaurus: Evidence of Feet in Whales", "abstract": "New specimens of middle Eocene Basilosaurus isis from Egypt include the first functional pelvic limb and foot bones known in Cetacea. These are important in corroborating the intermediate evolutionary position of archaeocetes between generalized Paleocene land mammals that used hind limbs in locomotion and Oligocene-to- Recent whales that lack functional pelvic limbs. The foot is paraxonic, consistent with derivation from mesonychid Condylarthra. Hind limbs of Basilosaurus are interpreted as copulatory guides.", "keyphrases": ["whale", "egypt", "hind limb"]}
{"id": "10.1346/CCMN.1991.0390604", "title": "Clay Mineralogy, Alteration History, and Economic Geology of the Whitemud Formation, Southern Saskatchewan, Canada", "abstract": "The Upper Cretaceous (Maastrichtian) Whitemud Formation is a potentially commercial kaolin deposit located in southern Saskatchewan and southeastern Alberta. The Whitemud Formation contains a lower kaolinitic sandstone, a middle lignite and carbonaceous shale, and an upper interbedded siltstone and claystone. The sediments that comprise the rocks of the Whitemud Formation were deposited on alluvial or upper deltaic plains located along the northwest flank of the Williston Basin.Mineralogy and textures were determined by X-ray powder diffraction, scanning electron microscopy, and optical microscopy. Kaolinite abundance increases upward from the underlying rocks of the Eastend Formation through the Whitemud Formation, and the abundance of smectite, micas, and feldspars decreases from the Eastend Formation into the Whitemud Formation. Vermiform kaolinite crystals are in close spatial association with feldspar and mica grains. Near the top of the Whitemud Formation, etched quartz and feldspar grains, and gibbsite suggest the presence of a strong chemical leaching environment.Mineral distributions, presence of root remains, p\u00e9dologie mottles, grain coatings composed of clay, and soil horizons indicate the Whitemud Formation sediments were modified by intense weathering in a paleosol environment.Kaolin concentrated from selected kaolinitic sandstone deposits, and beneficiated by oxidation, leaching, and high-intensity wet-magnetic separation has a product brightness up to filler quality. Recovery of lowabrasion kaolin is low and viscosity of a fine-particle kaolin fraction is high. Economics of producing a wet-processed filler-grade kaolin is marginal.", "keyphrases": ["southern saskatchewan", "williston basin", "clay"]}
{"id": "10.1111/jzo.12149", "title": "Ruminant mandibular tooth mesowear: a new scheme for increasing paleoecological sample sizes", "abstract": "Extension of the mesowear method to include the lower cheek teeth of ruminants will dramatically increase sample sizes and thus the statistical power of paleodietary inferences. However, the mesowear method of Fortelius and Solounias, which was designed for application to the upper molars, does not effectively separate ruminant species by diet when applied to the lower teeth. Upper and lower mesowear scores have sometimes been compared among non-analogous cusps (i.e. the buccal cusps of the maxillary teeth, which experience incursion and the buccal cusps of the mandibular teeth, which experience excursion during the chewing stroke). We therefore compare mesowear scores between the buccal cusps of maxillary cheek teeth and the lingual cusps of mandibular cheek for a large sample of ruminants because both cusps experience incursion during the chewing stroke. Using the original mesowear scoring method, we find dietary signal in both the maxillary and mandibular cheek teeth and a high correlation between them using both non-phylogenetic and phylogenetic comparative methods. Noting unique patterns of mesowear among the mandibular teeth, we also propose a new scoring method with additional wear categories that improves dietary inference when applied to the lower teeth and is highly repeatable. We also find that mandibular mesowear scores are consistently lower than for their maxillary counterparts. Although differential wear among the upper and lower teeth is much less apparent when applying our new scoring method, wear differences might relate to anisodonty (i.e. mandibular cheek teeth are narrower). Overall, we recommend our new scoring method for application to the lingual cusps of the lower second molars of fossil ruminants.", "keyphrases": ["sample size", "mesowear score", "ruminant"]}
{"id": "paleo.000599", "title": "A new cardiid bivalve from the Pliocene Baklan Basin (Turkey) and the origin of modern Ponto\u2010Caspian taxa", "abstract": "Abstract:\u2002 We present the first record of the cardiid genus Monodacna from the Pliocene of Anatolia, Turkey. Monodacna imrei sp. nov. was found in the Pliocene Killik Formation from the western margin of the Baklan Basin, in very marginal brackish to freshwater lacustrine deposits. The new record extends the stratigraphic range of the modern Ponto\u2010Caspian genus back into the Pliocene and adds to earlier evidence that modern Ponto\u2010Caspian taxa originated in the Pliocene of south\u2010western Turkey.", "keyphrases": ["turkey", "modern ponto\u2010caspian taxa", "mollusc assemblage", "micromammal fossil", "basin-fill"]}
{"id": "10.1111/j.1365-294X.2008.03899.x", "title": "Birth of a biome: insights into the assembly and maintenance of the Australian arid zone biota", "abstract": "The integration of phylogenetics, phylogeography and palaeoenvironmental studies is providing major insights into the historical forces that have shaped the Earth's biomes. Yet our present view is biased towards arctic and temperate/tropical forest regions, with very little focus on the extensive arid regions of the planet. The Australian arid zone is one of the largest desert landform systems in the world, with a unique, diverse and relatively well-studied biota. With foci on palaeoenvironmental and molecular data, we here review what is known about the assembly and maintenance of this biome in the context of its physical history, and in comparison with other mesic biomes. Aridification of Australia began in the Mid-Miocene, around 15 million years, but fully arid landforms in central Australia appeared much later, around 1-4 million years. Dated molecular phylogenies of diverse taxa show the deepest divergences of arid-adapted taxa from the Mid-Miocene, consistent with the onset of desiccation. There is evidence of arid-adapted taxa evolving from mesic-adapted ancestors, and also of speciation within the arid zone. There is no evidence for an increase in speciation rate during the Pleistocene, and most arid-zone species lineages date to the Pliocene or earlier. The last 0.8 million years have seen major fluctuations of the arid zone, with large areas covered by mobile sand dunes during glacial maxima. Some large, vagile taxa show patterns of recent expansion and migration throughout the arid zone, in parallel with the ice sheet-imposed range shifts in Northern Hemisphere taxa. Yet other taxa show high lineage diversity and strong phylogeographical structure, indicating persistence in multiple localised refugia over several glacial maxima. Similar to the Northern Hemisphere, Pleistocene range shifts have produced suture zones, creating the opportunity for diversification and speciation through hybridisation, polyploidy and parthenogenesis. This review highlights the opportunities that development of arid conditions provides for rapid and diverse evolutionary radiations, and re-enforces the emerging view that Pleistocene environmental change can have diverse impacts on genetic structure and diversity in different biomes. There is a clear need for more detailed and targeted phylogeographical studies of Australia's arid biota and we suggest a framework and a set of a priori hypotheses by which to proceed.", "keyphrases": ["biome", "maintenance", "aridification", "australia"]}
{"id": "paleo.008331", "title": "A new, exceptionally preserved juvenile specimen of Eusaurosphargis dalsassoi (Diapsida) and implications for Mesozoic marine diapsid phylogeny", "abstract": "Recently it was suggested that the phylogenetic clustering of Mesozoic marine reptile lineages, such as thalattosaurs, the very successful fish-shaped ichthyosaurs and sauropterygians (including plesiosaurs), among others, in a so-called \u2018superclade\u2019 is an artefact linked to convergent evolution of morphological characters associated with a shared marine lifestyle. Accordingly, partial \u2018un-scoring\u2019 of the problematic phylogenetic characters was proposed. Here we report a new, exceptionally preserved and mostly articulated juvenile skeleton of the diapsid reptile, Eusaurosphargis dalsassoi, a species previously recovered within the marine reptile \u2018superclade\u2019, for which we now provide a revised diagnosis. Using micro-computed tomography, we show that besides having a deep skull with a short and broad rostrum, the most outstanding feature of the new specimen is extensive, complex body armour, mostly preserved in situ, along its vertebrae, ribs, and forelimbs, as well as a row of flat, keeled ventrolateral osteoderms associated with the gastralia. As a whole, the anatomical features support an essentially terrestrial lifestyle of the animal. A review of the proposed partial character \u2018un-scoring\u2019 using three published data matrices indicate that this approach is flawed and should be avoided, and that within the marine reptile \u2018superclade\u2019 E. dalsassoi potentially is the sister taxon of Sauropterygia.", "keyphrases": ["eusaurosphargis dalsassoi", "diapsida", "sauropterygia"]}
{"id": "10.1080/02724634.1984.10012004", "title": "Late Cenozoic mammals from northwestern Mexico", "abstract": "ABSTRACT Ten geographically restricted vertebrate faunas are recognized in late Cenozoic deposits of northwestern Mexico. The late Hemphillian Yepomera fauna of Chihuahua with 27 mammal genera and the Irvingtonian El Golfo of Sonora with 23 mammal genera are the most diverse and most securely placed in a temporal framework among the ten late Cenozoic faunas of northwestern Mexico. The presently known Hemphillian (early Pliocene) vertebrate record of northwestern Mexico indicates an abundance and diversity of both horses and cricetid rodents, and suggests a center of diversificacion for these mammal groups in Mexico prior to the Great American Interchange.", "keyphrases": ["northwestern mexico", "chihuahua", "early pliocene"]}
{"id": "paleo.001907", "title": "CLASSIFICATION AND CONTROLS OF INTERNAL BANDING IN PALAEOZOIC STROMATOPOROIDS AND COLONIAL CORALS", "abstract": "Abstract:\u2002 Palaeozoic corals and stromatoporoids exhibit a variety of internal banding phenomena, many of which have been commonly interpreted as annual growth bands. We evaluate bands through analysis of colonial corals and stromatoporoids from three stratigraphic intervals: Upper Ordovician of Manitoba Canada, and Llandovery\u2013Wenlock and Ludlow of Gotland, Sweden. Banding features are divided into four categories: (1) absence of banding; (2) density banding formed by variation in density or form of elements; (3) growth\u2010interruption banding indicating growth cessation and regeneration; and (4) post\u2010mortem banding caused by compaction or diagenesis. For discrimination of band types, it is essential to examine internal structures and skeletal margins in thin sections or acetate peels. Species vary considerably in degree and type of banding; each has a distinct pattern of variation. We propose criteria to determine if banding is consistent with seasonally induced growth variation: (1) consistency in band character and thickness; (2) continuity of skeletal growth; (3) marginal features; and (4) evidence of diagenetic alteration. Density bands in tabulate and rugose corals probably represent annual growth variations, but results for stromatoporoids are more ambiguous; although stromatoporoids commonly show banding, unequivocal density banding is poorly developed and growth interruption generated most stromatoporoid banding. Cerioid rugose and tabulate corals possess the thickest density bands; the thinnest bands are in stromatoporoids and heliolitid tabulates.", "keyphrases": ["stromatoporoid", "colonial coral", "tabulate"]}
{"id": "10.1002/spp2.1033", "title": "A new dwarf seal from the late Neogene of South America and the evolution of pinnipeds in the southern hemisphere", "abstract": "Along the south\u2010western coast of South America, three genera of fossil phocids (true seals) have been formally described from the late Neogene: Acrophoca and Piscophoca from Chile and Peru, and, more recently, Hadrokirus from Peru, which all represent medium\u2010 to large\u2010sized phocids. Here, we report the discovery of Australophoca changorum gen. et sp. nov., a diminutive phocid from the late Miocene of the Bah\u00eda Inglesa Formation (northern Chile) and Pisco Formation (southern Peru), comparable in size with the smallest species of modern phocids. This taxon is based on diagnostic postcranial material, including a humerus that has an elongated deltopectoral crest but lacks an entepicondylar foramen; a femur with a subtrochanteric fossa, among other characters; in combination with a relatively small body size. All these features together distinguish A. changorum from all other reported pinnipeds. This new taxon not only increases the taxonomic and morphological diversity of phocids of the late Neogene of the eastern South Pacific Ocean, but it also provides new insights about the evolutionary history of fossil pinniped assemblages in South America and, broadly, in the southern hemisphere.", "keyphrases": ["neogene", "pinniped", "body size"]}
{"id": "10.1666/06069.1", "title": "Environmental determinants of marine benthic biodiversity dynamics through Triassic\u2013Jurassic time", "abstract": "Abstract Ecology is thought to be of crucial importance in determining taxonomic turnover at geological time scales, yet general links between ecology and biodiversity dynamics are still poorly explored in deep time. Here we analyze the relationships between the environmental affinities of Triassic\u2013Jurassic marine benthic genera and their biodiversity dynamics, using a large, taxonomically vetted data set of Triassic\u2013Jurassic taxonomic occurrences. On the basis of binomial probabilities of proportional occurrence counts, we identify environmental affinities of genera for (1) carbonate versus siliciclastic substrates, (2) onshore versus offshore depositional environments, (3) reefs versus level-bottom communities, and (4) tropical versus non-tropical latitudinal zones. Genera with affinities for carbonates, onshore environments, and reefs have higher turnover rates than genera with affinities for siliciclastic, offshore, and level-bottom settings. Differences in faunal turnover are largely due to differences in origination rates. Whereas previous studies have highlighted the direct influence of physical and biological factors in exploring environmental controls on evolutionary rates, our analyses show that the patterns can largely be explained by the partitioning of higher taxa with different evolutionary tempos among environments. The relatively slowly evolving bivalves are concentrated in siliciclastic rocks and in level-bottom communities. Furthermore, separate analyses on bivalves did not produce significant differences in turnover rates between environmental settings. The relationship between biodiversity dynamics and environments in our data set is thus governed by the partitioning of higher taxa within environmental categories and not directly due to greater chances of origination in particular settings. As this partitioning probably has ecological reasons rather than being a simple sampling artifact, we propose an indirect environmental control on evolutionary rates. Affinities for latitudinal zones are not linked to systematically different turnover rates, possibly because of paleoclimatic fluctuations and latitudinal migrations of taxa. However, the strong extinction spike of tropical genera in the Rhaetian calls for an important paleoclimatic component in the end-Triassic mass extinction.", "keyphrases": ["biodiversity dynamic", "environmental affinity", "fluctuation"]}
{"id": "paleo.005628", "title": "Mississippian crinoid biodiversity, biogeography and macroevolution", "abstract": "Abstract:\u2002 The biodiversity and biogeography of 217 genera of Mississippian crinoids from North America and the British Isles shed light on the macroevolutionary turnover between the Middle Palaeozoic and Late Palaeozoic Crinoid Evolutionary Faunas. This turnover resulted from steady differential extinction among clades during the middle Mississippian after crinoids reached their Phanerozoic peak of generic richness during the early Mississippian. This peak richness was primarily a function of Mississippian originations rather than Devonian\u2013holdover taxa. North America had 100\u2003per cent higher generic richness than the British Isles, but rarefaction analysis adjusts the difference to only 37\u2003per cent higher. Rarefaction demonstrated that North America had increased biodiversity, compared to the British Isles, almost entirely among monobathrid camerates, disparids and primitive cladids. In contrast, diplobathrid camerates, advanced cladids and flexibles had the same generic biodiversity between regions, when compared using rarefaction. The early Mississippian radiation resulted from two primary causes: (1) the expansion of Tournaisian carbonate ramps following the Frasnian mass extinction of reef faunas and (2) the predatory release in the Tournaisian following the end\u2010Famennian Hangenberg extinction of durophagous fishes. A majority of crinoid genera from the British Isles are cosmopolitan. When combined with rarefaction analysis and evidence for more first occurrences in North America, this suggests higher origination rates in North America, especially when carbonate ramps were widespread. With the gradual reduction in the area of carbonate ramps from the early to late Mississippian, in conjunction with the radiation of new durophagous fishes, camerate crinoids in particular experienced continuous background extinction, without replacement, beginning during the earliest Vis\u00e9an (late Osagean). By middle Vis\u00e9an time (late Meramecian) advanced cladids were dominant in all settings. This resulted in the transition from the Middle Palaeozoic to the Late Palaeozoic Crinoid Macroevolutionary Fauna.", "keyphrases": ["biogeography", "phanerozoic peak", "early mississippian", "cladid", "crinoid genera"]}
{"id": "paleo.007812", "title": "Cranial biomechanics underpins high sauropod diversity in resource-poor environments", "abstract": "High megaherbivore species richness is documented in both fossil and contemporary ecosystems despite their high individual energy requirements. An extreme example of this is the Late Jurassic Morrison Formation, which was dominated by sauropod dinosaurs, the largest known terrestrial vertebrates. High sauropod diversity within the resource-limited Morrison is paradoxical, but might be explicable through sophisticated resource partitioning. This hypothesis was tested through finite-element analysis of the crania of the Morrison taxa Camarasaurus and Diplodocus. Results demonstrate divergent specialization, with Camarasaurus capable of exerting and accommodating greater bite forces than Diplodocus, permitting consumption of harder food items. Analysis of craniodental biomechanical characters taken from 35 sauropod taxa demonstrates a functional dichotomy in terms of bite force, cranial robustness and occlusal relationships yielding two polyphyletic functional \u2018grades\u2019. Morrison taxa are widely distributed within and between these two morphotypes, reflecting distinctive foraging specializations that formed a biomechanical basis for niche partitioning between them. This partitioning, coupled with benefits associated with large body size, would have enabled the high sauropod diversities present in the Morrison Formation. Further, this provides insight into the mechanisms responsible for supporting the high diversities of large megaherbivores observed in other Mesozoic and Cenozoic communities, particularly those occurring in resource-limited environments.", "keyphrases": ["sauropod diversity", "environment", "robustness", "skull", "innovation"]}
{"id": "10.3140/bull.geosci.1586", "title": "150 million years old isopods on fishes: a possible case of palaeo-parasitism", "abstract": "Parasites are found in all habitats and within all groups of animals, and their influence on food webs, ecosystems and evolutionary development is significant. However, the fossil record of direct parasitism is very scarce. We present here probable examples of parasitic isopods on fishes from the Upper Jurassic Solnhofen Lithographic Limestones (150 million years old, southern Germany). Individual fishes appear to be infested with one to three isopods each. All specimens were documented with up-to-date imaging methods (macrophotography, stereo-photography, composite imaging). Position, orientation and other aspects clearly indicate that the isopods were already attached to the fishes before they died and hence do not represent scavengers but (more or less permanently) attached parasites. While the morphology of the specimens is somewhat uninformative about the systematic position of the isopods, their specific type of parasitism is an indicator for a position in the early lineage towards Cymothoidae. This would represent the first fossil record of this group of obligate fish parasites.", "keyphrases": ["isopod", "parasitism", "cymothoidae"]}
{"id": "paleo.005316", "title": "Redescription of Hexaconularia He and Yang, 1986 (Lower Cambrian, South China): implications for the affinities of conulariid\u2010like small shelly fossils", "abstract": "Abstract:\u2002 Hexaconularia, a Lower Cambrian small shelly fossil (SSF) that has been allied with conulariids and scyphozoan cnidarians, is redescribed and refigured. A salient feature of this monospecific genus is the presence of distinct apical and abapical regions. The apical region probably represents an embryonic shell that apparently lacked a basal attachment structure. Comparisons of this feature with the apical end of the smallest known conulariids and with conulariids terminating in an apical wall (schott) reveal substantial differences in structure and ornamentation. Differences in apical anatomy between conulariids and Arthrochites, possibly the nearest SSF relative of Hexaconularia, are also apparent. Comparisons of Hexaconularia with Punctatus, an SSF taxon showing distinct apical and abapical regions in both posthatching specimens and prehatching embryos, suggest that the early development of Hexaconularia was direct. These results have important implications for hypotheses of a conulariid/scyphozoan affinity for Hexaconularia and its possible SSF relatives, and they suggest that Hexaconularia\u2010bearing strata may yield prehatching embryos of this genus.", "keyphrases": ["small shelly fossil", "conulariid", "embryonic shell"]}
{"id": "10.1126/science.1229237", "title": "The Placental Mammal Ancestor and the Post\u2013K-Pg Radiation of Placentals", "abstract": "Let There Be Mammals The timing of the evolution and radiation of placental mammals and their most recent common ancestor has long been debated, with many questions surrounding the relationships of groups that pre- and postdate the Cretaceous-Paleogene boundary (66 million years ago). While the fossil record suggests that placental mammals radiated after the Cretaceous, molecular clocks have consistently placed the ancestors of mammalian lineages earlier. O'Leary et al. (p. 662; see the Perspective by Yoder) examined the morphology of fossil and extant taxa and conclude that living placentals originated and radiated after the Cretaceous and reconstruct the phenotype of the ancestral placental mammal. Fossil and DNA phylogenies suggest that placental mammals diversified in the Cenozoic and reconstruct the ancestral form. [Also see Perspective by Yoder] To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.", "keyphrases": ["placental", "common ancestor", "cenozoic", "k-pg", "molecular data"]}
{"id": "paleo.010672", "title": "Footprint evidence of early hominin locomotor diversity at Laetoli, Tanzania", "abstract": "Bipedal trackways discovered in 1978 at Laetoli site G, Tanzania and dated to 3.66 million years ago are widely accepted as the oldest unequivocal evidence of obligate bipedalism in the human lineage1\u20133. Another trackway discovered two years earlier at nearby site A was partially excavated and attributed to a hominin, but curious affinities with bears (ursids) marginalized its importance to the paleoanthropological community, and the location of these footprints fell into obscurity3\u20135. In 2019, we located, excavated and cleaned the site A trackway, producing a digital archive using 3D photogrammetry and laser scanning. Here we compare the footprints at this site with those of American black bears, chimpanzees and humans, and we show that they resemble those of hominins more than ursids. In fact, the narrow step width corroborates the original interpretation of a small, cross-stepping bipedal hominin. However, the inferred foot proportions, gait parameters and 3D morphologies of footprints at site A are readily distinguished from those at site G, indicating that a minimum of two hominin taxa with different feet and gaits coexisted at Laetoli.", "keyphrases": ["hominin", "tanzania", "ursid"]}
{"id": "paleo.010034", "title": "The first hyaenodont from the late Oligocene Nsungwe Formation of Tanzania: Paleoecological insights into the Paleogene-Neogene carnivore transition", "abstract": "Throughout the Paleogene, most terrestrial carnivore niches in Afro-Arabia were occupied by Hyaenodonta, an extinct lineage of placental mammals. By the end of the Miocene, terrestrial carnivore niches had shifted to members of Carnivora, a clade with Eurasian origins. The transition from a hyaenodont-carnivore fauna to a carnivoran-carnivore fauna coincides with other ecological changes in Afro-Arabia as tectonic conditions in the African Rift System altered climatic conditions and facilitated faunal exchange with Eurasia. Fossil bearing deposits in the Nsungwe Formation in southwestern Tanzania are precisely dated to ~25.2 Ma (late Oligocene), preserving a late Paleogene Afro-Arabian fauna on the brink of environmental transition, including the earliest fossil evidence of the split between Old World monkeys and apes. Here we describe a new hyaenodont from the Nsungwe Formation, Pakakali rukwaensis gen. et sp. nov., a bobcat-sized taxon known from a portion of the maxilla that preserves a deciduous third premolar and alveoli of dP4 and M1. The crown of dP3 bears an elongate parastyle and metastyle and a small, blade-like metacone. Based on alveolar morphology, the two more distal teeth successively increased in size and had relatively large protocones. Using a hyaenodont character-taxon matrix that includes deciduous dental characters, Bayesian phylogenetic methods resolve Pakakali within the clade Hyainailouroidea. A Bayesian biogeographic analysis of phylogenetic results resolve the Pakakali clade as Afro-Arabian in origin, demonstrating that this small carnivorous mammal was part of an endemic Afro-Arabian lineage that persisted into the Miocene. Notably, Pakakali is in the size range of carnivoran forms that arrived and began to diversify in the region by the early Miocene. The description of Pakakali is important for exploring hyaenodont ontogeny and potential influences of Afro-Arabian tectonic events upon mammalian evolution, providing a deep time perspective on the stability of terrestrial carnivore niches through time.", "keyphrases": ["hyaenodont", "oligocene", "carnivora"]}
{"id": "paleo.002361", "title": "Palaeoneurological clues to the evolution of defining mammalian soft tissue traits", "abstract": "A rich fossil record chronicles the distant origins of mammals, but the evolution of defining soft tissue characters of extant mammals, such as mammary glands and hairs is difficult to interpret because soft tissue does not readily fossilize. As many soft tissue features are derived from dermic structures, their evolution is linked to that of the nervous syutem, and palaeoneurology offers opportunities to find bony correlates of these soft tissue features. Here, a CT scan study of 29 fossil skulls shows that non-mammaliaform Prozostrodontia display a retracted, fully ossified, and non-ramified infraorbital canal for the infraorbital nerve, unlike more basal therapsids. The presence of a true infraorbital canal in Prozostrodontia suggests that a motile rhinarium and maxillary vibrissae were present. Also the complete ossification of the parietal fontanelle (resulting in the loss of the parietal foramen) and the development of the cerebellum in Probainognathia may be pleiotropically linked to the appearance of mammary glands and having body hair coverage since these traits are all controlled by the same homeogene, Msx2, in mice. These suggest that defining soft tissue characters of mammals were already present in their forerunners some 240 to 246 mya.", "keyphrases": ["non-mammaliaform prozostrodontia", "non-ramified infraorbital canal", "canal"]}
{"id": "paleo.010401", "title": "Learning by Heart: Cultural Patterns in the Faunal Processing Sequence during the Middle Pleistocene", "abstract": "Social learning, as an information acquisition process, enables intergenerational transmission and the stabilisation of cultural forms, generating and sustaining behavioural traditions within human groups. Archaeologically, such social processes might become observable by identifying repetitions in the record that result from the execution of standardised actions. From a zooarchaeological perspective, the processing and consumption of carcasses may be used to identify these types of phenomena at the sites. To investigate this idea, several faunal assemblages from Bolomor Cave (Valencia, Spain, MIS 9-5e) and Gran Dolina TD10-1 (Burgos, Spain, MIS 9) were analysed. The data show that some butchery activities exhibit variability as a result of multiple conditioning factors and, therefore, the identification of cultural patterns through the resulting cut-marks presents additional difficulties. However, other activities, such as marrow removal by means of intentional breakage, seem to reflect standardised actions unrelated to the physical characteristics of the bones. The statistical tests we applied show no correlation between the less dense areas of the bones and the location of impacts. Comparison of our experimental series with the archaeological samples indicates a counter-intuitive selection of the preferred locus of impact, especially marked in the case of Bolomor IV. This fact supports the view that bone breakage was executed counter-intuitively and repetitively on specific sections because it may have been part of an acquired behavioural repertoire. These reiterations differ between levels and sites, suggesting the possible existence of cultural identities or behavioural predispositions dependant on groups. On this basis, the study of patterns could significantly contribute to the identification of occupational strategies and organisation of the hominids in a territory. In this study, we use faunal data in identifying the mechanics of intergenerational information transmission within Middle Pleistocene human communities and provide new ideas for the investigation of occupational dynamics from a zooarchaeological approach.", "keyphrases": ["middle pleistocene", "action", "bone breakage", "butchery tradition", "anatomical constraint"]}
{"id": "10.1080/02724634.2016.1111224", "title": "The Femoral Ontogeny and Long Bone Histology of the Middle Triassic (?Late Anisian) Dinosauriform Asilisaurus kongwe and Implications for the Growth of Early Dinosaurs", "abstract": "ABSTRACT The ontogeny of early-diverging dinosauromorphs is poorly understood because few ontogenetic series from the same species-level taxon are known and what is available has not been extensively documented. The large numbers of skeletal elements of the silesaurid Asilisaurus kongwe recently recovered from Tanzania provide an opportunity to examine the ontogenetic trajectory of the earliest known member of Ornithodira and one of the closest relatives to Dinosauria. We examined the ontogeny of the femur and the histology of a series of long bone elements. We observed bone scar variation in a series of femora (n = 27) of different lengths (73.8\u2013177.2 mm). We hypothesize that most femora follow a similar developmental trajectory; however, we observed sequence polymorphism in the order of appearance and shape of bone scars, and we quantified this polymorphism using ontogenetic sequence analysis (OSA). Additionally, five femora, three tibiae, a fibula, and a humerus were thin-sectioned to examine osteological tissues. No lines of arrested growth (LAGs) are present in any specimen, and there is little histological information about the ontogenetic stage of femora, although none have slowed or ceased growth. The woven-fibered bone present in the cortex of elements sectioned is similar to that of the earliest dinosaurs. This sequence polymorphism provides an alternate hypothesis for the robust/gracile dichotomy found in early dinosaurs often interpreted as sexual dimorphism. The shared femoral features found in Asilisaurus and early dinosaurs suggest that this ontogenetic pattern is plesiomorphic for Dinosauria, and that size is a poor predictor of maturity in early dinosauriforms.", "keyphrases": ["early dinosaur", "ontogenetic sequence analysis", "osa"]}
{"id": "10.1029/2008PA001615", "title": "Eustatic variations during the Paleocene\u2010Eocene greenhouse world", "abstract": "We reconstruct eustatic variations during the latest Paleocene and earliest Eocene (\u223c58-52 Ma). Dinoflagellate cysts, grain size fractions, and organic biomarkers in marine sections at four sites from three continents indicate an increased distance to the coast during the Paleocene-Eocene thermal maximum (PETM). The same trend is recognized in published records from other sites around the world. Together, the data indicate a eustatic rise during the PETM, beginning 20 to 200 ka before the globally recorded negative carbon isotope excursion (CIE) at \u223c55.5 Ma. Although correlations are tentative, we recognize other global transgressions during Chrons C25n and C24n. The latter may be associated with Eocene Thermal Maximum 2 (\u223c53.5 Ma) or the \"X\"-event (\u223c52 Ma). These results suggest a link between global sea level and \"hyperthermal\" intervals, potentially because of the melting of small alpine ice sheets on Antarctica, thermal expansion of seawater, or both. However, the early onset of sea level rise relative to the CIE of the PETM suggests contributions from other mechanisms, perhaps decreasing ocean basin volume, on sea level rise. Copyright 2008 by the American Geophysical Union.", "keyphrases": ["petm", "sea level", "thermal expansion", "onset", "eustatic variation"]}
{"id": "10.3301/IJG.2019.07", "title": "In search of the Burdigalian GSSP: new evidence from the Contessa Section (Italy)", "abstract": "The Contessa Section is a reference section for the early Miocene in the Mediterranean. Along this 36 m thick section 115 samples were collected and analysed for an integrated bio-magnetostratigraphic study through the Scaglia Cinerea and Bisciaro formations. Planktonic foraminifera were analysed semi-quantitatively, while calcareous nannofossils were examined using the standard quantitative method. A reliable biozonation for both fossil groups was then accomplished. The paleomagnetic analyses identified a sequence of magnetozones, then correlated with the ATNTS using the calcareous plankton bioevents. The investigated interval extends from foraminiferal Zone P22 (Chattian) to MMi2c (Burdigalian) and from calcareous nannofossils Zone MNP25a to MNN3a, thus from Chron C7An to C5En. Therefore, the section chronologically spans from 24.80 Ma to18.10 Ma. Three hiatuses were recognised along the section: H1 at 0.63 m from the base (comprising a minimum time interval from 24.36 Ma to 23.38 Ma), H2 at 12.33 m (between 21.80 Ma and 21.35 Ma) and H3 at 34.03 (between 19.21 Ma and 18.40 Ma). All three hiatuses were correlated with regional megahiatuses identified in the North Atlantic Ocean and in the Paratethys area. Furthermore, the First Occurrenceof the calcareous nannofossil Helicosphera ampliaperta is recognised within Chron C6An.2n at 19.77 m from the base (6 m above the volcaniclastic Raffaello Level). This event provisionally defines the Aquitanian/Burdigalian boundary according to the literature. Thus, the Contessa Section is a possible candidate for the definition of theBurdigalian Global Stratigraphic Section and Point. Finally, the age of the Raffaello Level (a regional marker horizon for the early Miocene) is discussed in this new integrated stratigraphic framework, falling in Chron C6AAn and dated between 21.09 Ma and 21.08 Ma.", "keyphrases": ["contessa section", "time interval", "hiatus"]}
{"id": "paleo.002052", "title": "Fossil lemurs from Egypt and Kenya suggest an African origin for Madagascar\u2019s aye-aye", "abstract": "In 1967 G.G. Simpson described three partial mandibles from early Miocene deposits in Kenya that he interpreted as belonging to a new strepsirrhine primate, Propotto. This interpretation was quickly challenged, with the assertion that Propotto was not a primate, but rather a pteropodid fruit bat. The latter interpretation has not been questioned for almost half a century. Here we re-evaluate the affinities of Propotto, drawing upon diverse lines of evidence to establish that this strange mammal is a strepsirrhine primate as originally suggested by Simpson. Moreover, our phylogenetic analyses support the recognition of Propotto, together with late Eocene Plesiopithecus from Egypt, as African stem chiromyiform lemurs that are exclusively related to the extant aye-aye (Daubentonia) from Madagascar. Our results challenge the long-held view that all lemurs are descended from a single ancient colonization of Madagascar, and present an intriguing alternative scenario in which two lemur lineages dispersed from Africa to Madagascar independently, possibly during the later Cenozoic.", "keyphrases": ["madagascar", "aye-aye", "colonization"]}
{"id": "paleo.011940", "title": "Early high rates and disparity in the evolution of ichthyosaurs", "abstract": "How clades diversify early in their history is integral to understanding the origins of biodiversity and ecosystem recovery following mass extinctions. Moreover, diversification can represent evolutionary opportunities and pressures following ecosystem changes. Ichthyosaurs, Mesozoic marine reptiles, appeared after the end-Permian mass extinction and provide opportunities to assess clade diversification in a changed world. Using recent cladistic data, skull length data, and the most complete phylogenetic trees to date for the group, we present a combined disparity, morphospace, and evolutionary rates analysis that reveals the tempo and mode of ichthyosaur morphological evolution through 160 million years. Ichthyosaur evolution shows an archetypal early burst trend, driven by ecological opportunity in Triassic seas, and an evolutionary bottleneck leading to a long-term reduction in evolutionary rates and disparity. This is represented consistently across all analytical methods by a Triassic peak in ichthyosaur disparity and evolutionary rates, and morphospace separation between Triassic and post-Triassic taxa.", "keyphrases": ["ichthyosaur", "diversification", "mesozoic marine reptile", "ecological opportunity", "ptme"]}
{"id": "paleo.010247", "title": "Ester-Mediated Amide Bond Formation Driven by Wet\u2013Dry Cycles: A Possible Path to Polypeptides on the Prebiotic Earth**", "abstract": "Although it is generally accepted that amino acids were present on the prebiotic Earth, the mechanism by which \u03b1-amino acids were condensed into polypeptides before the emergence of enzymes remains unsolved. Here, we demonstrate a prebiotically plausible mechanism for peptide (amide) bond formation that is enabled by \u03b1-hydroxy acids, which were likely present along with amino acids on the early Earth. Together, \u03b1-hydroxy acids and \u03b1-amino acids form depsipeptides\u2014oligomers with a combination of ester and amide linkages\u2014in model prebiotic reactions that are driven by wet\u2013cool/dry\u2013hot cycles. Through a combination of ester\u2013amide bond exchange and ester bond hydrolysis, depsipeptides are enriched with amino acids over time. These results support a long-standing hypothesis that peptides might have arisen from ester-based precursors.", "keyphrases": ["bond formation", "prebiotic earth", "amino acid", "reaction", "ester-amide exchange"]}
{"id": "paleo.002704", "title": "Waptia fieldensis Walcott, a mandibulate arthropod from the middle Cambrian Burgess Shale", "abstract": "Waptia fieldensis Walcott, 1912 is one of the iconic animals from the middle Cambrian Burgess Shale biota that had lacked a formal description since its discovery at the beginning of the twentieth century. This study, based on over 1800 specimens, finds that W. fieldensis shares general characteristics with pancrustaceans, as previous authors had suggested based mostly on its overall aspect. The cephalothorax is covered by a flexible, bivalved carapace and houses a pair of long multisegmented antennules, palp-bearing mandibles, maxillules, and four pairs of appendages with five-segmented endopods\u2014the anterior three pairs with long and robust enditic basipods, the fourth pair with proximal annulations and lamellae. The post-cephalothorax has six pairs of lamellate and fully annulated appendages which appear to be extensively modified basipods rather than exopods. The front part of the body bears a pair of stalked eyes with the first ommatidia preserved in a Burgess Shale arthropod, and a median \u2018labral\u2019 complex flanked by lobate projections with possible affinities to hemi-ellipsoid bodies. Waptia confirms the mandibulate affinity of hymenocarines, retrieved here as part of an expanded Pancrustacea, thereby providing a novel perspective on the evolutionary history of this hyperdiverse group. We construe that Waptia was an active swimming predator of soft prey items, using its anterior appendages for food capture and manipulation, and also potentially for clinging to epibenthic substrates.", "keyphrases": ["arthropod", "carapace", "hymenocarine", "waptia fieldensis walcott"]}
{"id": "paleo.008135", "title": "When a 520 million-year-old Chengjiang fossil meets a modern micro-CT \u2013 a case study", "abstract": "The 520 million-year-old Chengjiang biota of China (UNESCO World Heritage) presents the earliest known evidence of the so-called Cambrian Explosion. Studies, however, have mainly been limited to the information exposed on the surface of the slabs. Thus far, structures preserved inside the slabs were accessed by careful removal of the matrix, in many cases with the unfortunate sacrifice of some \"less important\" structures, which destroys elements of exceptionally preserved specimens. Here, we show for the first time that microtomography (micro-CT) can reveal structures situated inside a Chengjiang fossil slab without causing any damage. In the present study a trilobitomorph arthropod (Xandarella spectaculum) can be reliably identified only with the application of micro-CT. We propose that this technique is an important tool for studying three-dimensionally preserved Chengjiang fossils and, most likely, also those from other biota with a comparable type of preservation, specifically similar iron concentrations.", "keyphrases": ["chengjiang fossil", "micro-ct", "x-ray"]}
{"id": "paleo.004368", "title": "Fibres and cellular structures preserved in 75-million\u2013year-old dinosaur specimens", "abstract": "Exceptionally preserved organic remains are known throughout the vertebrate fossil record, and recently, evidence has emerged that such soft tissue might contain original components. We examined samples from eight Cretaceous dinosaur bones using nano-analytical techniques; the bones are not exceptionally preserved and show no external indication of soft tissue. In one sample, we observe structures consistent with endogenous collagen fibre remains displaying \u223c67 nm banding, indicating the possible preservation of the original quaternary structure. Using ToF-SIMS, we identify amino-acid fragments typical of collagen fibrils. Furthermore, we observe structures consistent with putative erythrocyte remains that exhibit mass spectra similar to emu whole blood. Using advanced material characterization approaches, we find that these putative biological structures can be well preserved over geological timescales, and their preservation is more common than previously thought. The preservation of protein over geological timescales offers the opportunity to investigate relationships, physiology and behaviour of long extinct animals.", "keyphrases": ["organic remain", "tissue", "dinosaur bone", "erythrocyte"]}
{"id": "10.1017/S0033822200048384", "title": "The Middle to Upper Paleolithic Sequence of Buran-Kaya III (Crimea, Ukraine): New Stratigraphic, Paleoenvironmental, and Chronological Results", "abstract": "Buran-Kaya III is a rockshelter located in Crimea (Ukraine). It provides an exceptional stratigraphic sequence extending from the Middle Paleolithic to the Neolithic. Nine Paleolithic layers have been attributed to the Streletskaya or eastern Szeletian, Micoquian, Aurignacian, Gravettian, and Swiderian cultural traditions. Human remains from the richest Gravettian layer (6-1) are radiocarbon dated to 31.9 ka BP, and therefore represent, with Pe\u015ftera cu Oase (Romania), one of the oldest anatomically modern humans in Europe. The aim of this study is to obtain a controlled stratigraphic sequence of Buran-Kaya III with new 14C dates from faunal and human bones, in their paleoenvironmental context. During our new excavations (2009\u20132011), sediments, bones, and teeth from the stratigraphical layers were sampled for sedimentological, geochemical, and 14C analyses. Fossil bones from the 2001 excavations were also analyzed. Accelerator mass spectrometry (AMS) 14C dating, including cross-dating, was performed at Groningen, Saclay/Gif-sur-Yvette, and Oxford. Biogeochemical analysis was used to test the integrity of the bone collagen. Dates were modeled using a Bayesian approach. The sedimentological, paleoenvironmental, and chronological data are mutually consistent and show that the Paleolithic human occupations at Buran-Kaya III range from the end of MIS 3 to early MIS 1. These results provide a new chronological and paleoenvironmental framework for the human settlements in eastern Europe during the late Middle and the Upper Paleolithic.", "keyphrases": ["buran-kaya iii", "ukraine", "eastern europe"]}
{"id": "10.1139/e79-011", "title": "Mammals from the Upper Cretaceous Oldman Formation, Alberta. III. Eutheria", "abstract": "Eutherian mammals from the Upper Cretaceous Oldman Formation, Alberta, are described. These include the leptictid proteutherian Gypsonictops lewisi Sahni, which has five lower premolars and was probably the direct lineal ancestor of G. hypoconus Simpson of Lancian age; a new genus and species of primitive and generalized erinaceoid insectivore, which is the most adequate dental ancestor known for all Lipotyphla, Tupaiidae, Primates, Dermoptera, Chiroptera, and all of the ungulate mammals; and the first pre-Lancian occurrence in North America of the Family Palaeoryctidae.", "keyphrases": ["alberta", "eutherian mammal", "north america"]}
{"id": "10.2110/palo.2014.064", "title": "SEDIMENTARY FACIES AND DEPOSITIONAL ENVIRONMENTS OF DIVERSE EARLY PALEOCENE FLORAS, NORTH-CENTRAL SAN JORGE BASIN, PATAGONIA, ARGENTINA", "abstract": "Abstract We here investigate the sedimentology of the early Danian (ca. 66\u201364 Ma) Salamanca Formation in the north-central San Jorge Basin, southern Chubut Province, Patagonia, Argentina, in order to place the outstandingly diverse and well-preserved fossil floras it contains into specific environmental settings. These assemblages are among very few of Danian age from the entire Southern Hemisphere and thus provide critical data about geographic variation in recovery from the end-Cretaceous extinction. Understanding the depositional context of the Salamanca floras is necessary for comparison with other assemblages and for interpreting their exceptional preservation. The Salamanca Formation was deposited above a widespread erosional sequence boundary (SB-1) resulting from a relative base level rise and widespread marine transgression during the early Danian (Chron C29n). In response to this increase in accommodation space, a broad, shallow estuary formed that most likely extended westward at least as far as the San Bernardo belt. A transgressive systems tract was deposited in this estuary, consisting of bioturbated sand fining upwards to silt. The maximum marine flooding surface at the beginning of the highstand systems tract is defined by well laminated, unburrowed, clay deposits of a low energy, deep shelf. The Salamanca highstand systems tract (HST) consists of sandy and silty facies capped by accreting subtidal bars and sandy shoals containing an abundance of tidal indicators, suggesting deposition proximal to the San Jorge paleo-estuary head. A second sequence boundary (SB-2), formed during Chron C28r and early C28n, separates the older highstand deposits from younger lowstand and transgressive deposits. These consist of estuarine sand shoals, trough cross-bedded sands deposited in aggrading, fluvially influenced tidal channels, tidal flat muds, and bayhead deltas. The best preservation of compression floras and petrified trees occurred near the tops of subtidal bars below SB-2; at the end of the shallowing-upward cycle that caps the second HST; and in fluvially-influenced tidal channels, tidal flat mudstones, and bayhead deltas of the lowstand and transgressive systems tracts that lie above SB-2. These settings were proximal to the source forests and had rapid rates of burial. We interpret the dark muds of the Banco Negro Inferior, which cap the Salamanca Formation, as a late transgressive and highstand systems tract deposited during a time of rising groundwater table and declining river slopes in a widespread, lowland coastal forest.", "keyphrases": ["depositional environment", "salamanca formation", "tidal channel", "mudstone"]}
{"id": "10.1002/ajp.22506", "title": "What did Hadropithecus eat, and why should paleoanthropologists care?", "abstract": "Over 40 years ago, Clifford Jolly noted different ways in which Hadropithecus stenognathus converged in its craniodental anatomy with basal hominins and with geladas. The Malagasy subfossil lemur Hadropithecus departs from its sister taxon, Archaeolemur, in that it displays comparatively large molars, reduced incisors and canines, a shortened rostrum, and thickened mandibular corpus. Its molars, however, look nothing like those of basal hominins; rather, they much more closely resemble molars of grazers such as Theropithecus. A number of tools have been used to interpret these traits, including dental microwear and texture analysis, molar internal and external morphology, and finite element analysis of crania. These tools, however, have failed to provide support for a simple dietary interpretation; whereas there is some consistency in the inferences they support, dietary inferences (e.g., that it was graminivorous, or that it specialized on hard objects) have been downright contradictory. Cranial shape may correlate poorly with diet. But a fundamental question remains unresolved: why do the various cranial and dental convergences exemplified by Hadropithecus, basal hominins, and Theropithecus exist? In this paper we review prior hypotheses regarding the diet of Hadropithecus. We then use stable carbon and nitrogen isotope data to elucidate this species' diet, summarizing earlier stable isotope analyses and presenting new data for lemurs from the central highlands of Madagascar, where Hadropithecus exhibits an isotopic signature strikingly different from that seen in other parts of the island. We offer a dietary explanation for these differences. Hadropithecus likely specialized neither on grasses nor hard objects; its staples were probably the succulent leaves of CAM plants. Nevertheless, aspects of prior hypotheses regarding the ecological significance of its morphology can be supported. Am. J. Primatol. 78:1098\u20131112, 2016. \u00a9 2015 Wiley Periodicals, Inc.", "keyphrases": ["hadropithecus", "central highland", "cam plant"]}
{"id": "paleo.013044", "title": "Investigating the Influence of Climate Changes on Rodent Communities at a Regional-Scale (MIS 1-3, Southwestern France)", "abstract": "Terrestrial ecosystems have continuously evolved throughout the Late Pleistocene and the Holocene, deeply affected by both progressive environmental and climatic modifications, as well as by abrupt and large climatic changes such as the Heinrich or Dansgaard-Oeschger events. Yet, the impacts of these different events on terrestrial mammalian communities are poorly known, as is the role played by potential refugia on geographical species distributions. This study examines community changes in rodents of southwestern France between 50 and 10 ky BP by integrating 94 dated faunal assemblages coming from 37 archaeological sites. This work reveals that faunal distributions were modified in response to abrupt and brief climatic events, such as Heinrich events, without actually modifying the rodent community on a regional scale. However, the succession of events which operated between the Late Pleistocene and the Holocene gradually led to establishing a new rodent community at the regional scale, with intermediate communities occurring between the B\u00f8lling and the Aller\u00f8d.", "keyphrases": ["rodent", "southwestern france", "late pleistocene"]}
{"id": "paleo.005120", "title": "Phenotypic and evolutionary implications of modulating the ERK-MAPK cascade using the dentition as a model", "abstract": "The question of phenotypic convergence across a signalling pathway has important implications for both developmental and evolutionary biology. The ERK-MAPK cascade is known to play a central role in dental development, but the relative roles of its components remain unknown. Here we investigate the diversity of dental phenotypes in Spry2 -/-, Spry4 -/-, and Rsk2 -/Y mice, including the incidence of extra teeth, which were lost in the mouse lineage 45 million years ago (Ma). In addition, Sprouty-specific anomalies mimic a phenotype that is absent in extant mice but present in mouse ancestors prior to 9 Ma. Although the mutant lines studied display convergent phenotypes, each gene has a specific role in tooth number determination and crown patterning. The similarities found between teeth in fossils and mutants highlight the pivotal role of the ERK-MAPK cascade during the evolution of the dentition in rodents.\nThe extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK-MAPK) pathway is a central regulator of tooth development. This cascade is typically initiated by the binding of a growth factor to a receptor tyrosine kinase (RTK), which triggers the phosphorylation of successive kinases and culminates in activation of effector kinases and the transcription of target genes (Fig. 1 ) 1 . The MAPK signalling pathway has been intensively studied by cancer biologists because of its effects on regulation of cell proliferation and survival 1,2 , but this pathway is also important throughout mouse embryogenesis 3 . The pathway has been investigated in numerous embryonic processes, including development of the central nervous system and mesodermal derivatives 4,5 , skeletal development 6 , and tooth development [7] [8] [9] [10] [11] .\nTooth development is a well-documented example of ectodermal organ development. It is a tightly regulated process arising from the crosstalk between dental epithelium and its underlying mesenchyme 12 . The signalling networks responsible for properly building the dentition have been heavily investigated, and numerous members of the ERK-MAPK signalling pathway are known to play a role in tooth development. Early studies examined the fibroblast growth factors (FGFs) that activate their receptors (FGFRs),", "keyphrases": ["dentition", "pathway", "tooth"]}
{"id": "paleo.003482", "title": "A large extinct marabou stork in African Pliocene hominid sites, and a review of the fossil species of Leptoptilos", "abstract": "New fossils of the family Ciconiidae from Pliocene hominid localities in Chad and Ethiopia are described, and several are shown to belong to Leptoptilos falconeri, originally known from the late Pliocene of the Siwalik Hills of India. Comparisons with all the hitherto known species of large Ciconiidae, and with an enlarged sample representing extant species, lead to a re-evaluation of some extinct taxa. Several synonymies are proposed, reflecting better the past diversity for this group. L. pliocenicus (Pliocene, Ukraine) is equivalent to L. cf. falconeri. Cryptociconia indica (late Pliocene, Siwalik Hills) belongs to Leptoptilos, and is probably either extant L. dubius or female L. falconeri. L. siwalicensis, from the same locality and also tentatively reported from the late Miocene of Northern Pakistan, is better referred to as Leptoptilini gen. et sp. indet. We consider the two following species as valid. L. titan (Pleistocene, Java) may be a late offshot of the lineage of L. falconeri. L. richae (late Miocene, Tunisia) is the size of L. crumeniferus, and is distinct from L. falconeri. Thus, L. falconeri remains the only ascertained extinct Pliocene species in the tribe Leptoptilini. It was a widespread \"giant\" marabou stork, in the Pliocene of southern Asia, as well as northern and eastern Africa where it coexisted with different Pliocene hominids, and probably eastern Europe. It weighed up to about 20 kg, reached 2 m in height, and had probably slightly reduced forelimbs. It became extinct by the end of the Pliocene. L. falconeri is an example of a biogeographical link at the species level between the African and Eurasian faunas in the Pliocene. The fossil record indicates the presence of at least one other lineage in Africa since the early Miocene, similar in size to the extant L. crumeniferus.", "keyphrases": ["marabou stork", "leptoptilos", "india", "extant specie"]}
{"id": "paleo.003285", "title": "Cranial Morphology of the Carboniferous-Permian Tetrapod Brachydectes newberryi (Lepospondyli, Lysorophia): New Data from \u00b5CT", "abstract": "Lysorophians are a group of early tetrapods with extremely elongate trunks, reduced limbs, and highly reduced skulls. Since the first discovery of this group, general similarities in outward appearance between lysorophians and some modern lissamphibian orders (specifically Urodela and Gymnophiona) have been recognized, and sometimes been the basis for hypotheses of lissamphibian origins. We studied the morphology of the skull, with particular emphasis on the neurocranium, of a partial growth series of the lysorophian Brachydectes newberryi using x-ray micro-computed tomography (\u03bcCT). Our study reveals similarities between the braincase of Brachydectes and brachystelechid recumbirostrans, corroborating prior work suggesting a close relationship between these taxa. We also describe the morphology of the epipterygoid, stapes, and quadrate in this taxon for the first time. Contra the proposals of some workers, we find no evidence of expected lissamphibian synapomorphies in the skull morphology in Brachydectes newberryi, and instead recognize a number of derived amniote characteristics within the braincase and suspensorium. Morphology previously considered indicative of taxonomic diversity within Lysorophia may reflect ontogenetic rather than taxonomic variation. The highly divergent morphology of lysorophians represents a refinement of morphological and functional trends within recumbirostrans, and is analogous to morphology observed in many modern fossorial reptiles.", "keyphrases": ["morphology", "lysorophia", "recumbirostran"]}
{"id": "10.1111/pala.12454", "title": "Endocranial anatomy and life habits of the Early Triassic archosauriform Proterosuchus fergusi", "abstract": "Proterosuchids are an important group of carnivorous basal archosauriforms characterized by a bizarre and enigmatic downturned premaxilla that overhangs the lower jaw. They are particularly significant because they radiated in the immediate aftermath of the Permian\u2013Triassic mass extinction and represent one of the best known \u2018disaster taxa\u2019 following that event. While traditionally considered to be semi\u2010aquatic, recent histological studies and geological data have suggested that it is more likely that they inhabited terrestrial environments. By using computed tomographic (CT) data, we virtually reconstruct the brain endocast and endosseous labyrinths of two adult specimens of Proterosuchus fergusi from the earliest Triassic of South Africa, in an attempt to understand its life habits within the context of basal archosauriform evolution. Endocasts reveal that the brain cavity is tubular in shape and the endosseous labyrinths are highly pyramidal. The angle of the lateral semicircular canal suggests that P. fergusi naturally held its head upwards ~17\u00b0, while the length of the cochlear duct suggests its auditory abilities were specialized towards low\u2010frequency sounds. Furthermore, beam theory analysis suggests that the rostrum of P. fergusi is highly resistant to both bending and torsion when compared to modern crocodilians, although this resistance is neither enhanced nor reduced by the overhanging premaxilla. Comparative anatomical analyses suggest P. fergusi was probably a semi\u2010aquatic, generalist apex predator capable of surviving the harsh environmental perturbations of the Early Triassic.", "keyphrases": ["anatomy", "life habit", "proterosuchus fergusi", "brain"]}
{"id": "10.1111/j.1096-3642.2006.00205.x", "title": "The cranial skeleton of the Early Permian aquatic reptile Mesosaurus tenuidens: implications for relationships and palaeobiology", "abstract": "The cranial osteology of the aquatic reptile Mesosaurus tenuidens is redescribed on the basis of new and previously examined materials from the Lower Permian of both southern Africa and South America. Mesosaurus is distinguished from other mesosaurs in exhibiting an absolutely larger skull and possessing relatively longer marginal teeth. The teeth gradually angle outwards as one progresses anteriorly in the tooth row and become conspicuously procumbent at the tip of the snout. The suggestion that mesosaurs used their conspicuous dental apparatus as a straining device for filter feeding is based upon erroneous reconstruction of a high number of teeth in this mesosaur. Reinterpretation of the morphology and the organization of the marginal teeth of Mesosaurus suggests that they were used to capture individually small, nektonic prey. General morphological aspects of the skull support the idea that Mesosaurus was an aquatic predator and that the skull was well adapted for feeding in an aqueous environment. The anatomical review permits critical reappraisal of several cranial characters that have appeared in recent phylogenetic analyses of early amniotes. Emendation of problematic characters and reanalysis of amniote phylogeny using a slightly modified data matrix from the literature strengthens the hypothesis that mesosaurs form a clade with millerettids, procolophonoids and pareiasaurs within Reptilia.\u00a0\u00a9 2006 The Linnean Society of London, Zoological Journal of the Linnean Society, 2006, 146, 345\u2013368.", "keyphrases": ["aquatic reptile mesosaurus", "mesosaur", "skull", "tooth"]}
{"id": "paleo.005241", "title": "Reconstructing the past: methods and techniques for the digital restoration of fossils", "abstract": "During fossilization, the remains of extinct organisms are subjected to taphonomic and diagenetic processes. As a result, fossils show a variety of preservational artefacts, which can range from small breaks and cracks, disarticulation and fragmentation, to the loss and deformation of skeletal structures and other hard parts. Such artefacts can present a considerable problem, as the preserved morphology of fossils often forms the basis for palaeontological research. Phylogenetic and taxonomic studies, inferences on appearance, ecology and behaviour and functional analyses of fossil organisms strongly rely on morphological information. As a consequence, the restoration of fossil morphology is often a necessary prerequisite for further analyses. Facilitated by recent computational advances, virtual reconstruction and restoration techniques offer versatile tools to restore the original morphology of fossils. Different methodological steps and approaches, as well as software are outlined and reviewed here, and advantages and disadvantages are discussed. Although the complexity of the restorative processes can introduce a degree of interpretation, digitally restored fossils can provide useful morphological information and can be used to obtain functional estimates. Additionally, the digital nature of the restored models can open up possibilities for education and outreach and further research.", "keyphrases": ["restoration", "artefact", "deformation", "fossil organism"]}
{"id": "10.1080/08912963.2018.1506777", "title": "Holocene amphibians and reptiles from Voroncha (Belarus): Comparative osteology, paleopathology and paleobiogeography", "abstract": "ABSTRACT The Voroncha site is an accumulation of Holocene small vertebrates, from which numerous amphibian and reptile remains have been recovered continuously over the course of many years. The accumulation has been said to represent a badger or fox den on a gully slope. The latest available collection contains some 11,538 herpetofauna bones suitable for systematic identification. This assemblage includes two caudates (Lissotriton vulgaris and Triturus cristatus), five anurans (Bufo bufo, Pelophylax lessonae, Pelophylax ridibundus, Rana arvalis, and Rana temporaria), one anguid lizard (Anguis fragilis sl), one lacertid lizard (Zootoca vivipara), and two snakes (Natrix natrix and Vipera berus). This paper describes the comparative characteristics of these bones. The considerable quantity of fossils helps to better visualize the identification criteria for the higher taxonomic categories. In addition, the great number of the bones identified at the species level reveals considerable intraspecific variability for some elements. This study complements previous studies by adding L. vulgaris, T. cristatus, B. bufo, P. ridibundus, R. arvalis, Z. vivipara, N. natrix and V. berus to the site\u2019s faunal record. Voroncha represents the first fossil record for caudates in the region of Belarus and the first record for Z. vivipara in the western East European Plain.", "keyphrases": ["amphibian", "genus rana", "flat dorsal surface"]}
{"id": "10.1126/science.1260947", "title": "Linked canopy, climate, and faunal change in the Cenozoic of Patagonia", "abstract": "Fluctuations revealed in fossil forests The reconstruction of past vegetation unlocks the door to understanding ecological changes associated with climatic change. But it is also difficult. Dunn et al. developed a method for assessing changes in vegetation openness based on epidermal cell morphology from conserved plant tissue. Applying this method to fossil assemblages from Patagonia, they show how vegetation structure changed over the Cenozoic era (49 to 11 million years ago). These changes map onto the known climate changes over this period and can also be used to track how the evolution of herbivorous mammals responded to vegetation structure. Science, this issue p. 258 A reconstruction of leaf area index from plant microfossils reveals a 38-million-year record of habitat change. Vegetation structure is a key determinant of ecosystems and ecosystem function, but paleoecological techniques to quantify it are lacking. We present a method for reconstructing leaf area index (LAI) based on light-dependent morphology of leaf epidermal cells and phytoliths derived from them. Using this proxy, we reconstruct LAI for the Cenozoic (49 million to 11 million years ago) of middle-latitude Patagonia. Our record shows that dense forests opened up by the late Eocene; open forests and shrubland habitats then fluctuated, with a brief middle-Miocene regreening period. Furthermore, endemic herbivorous mammals show accelerated tooth crown height evolution during open, yet relatively grass-free, shrubland habitat intervals. Our Patagonian LAI record provides a high-resolution, sensitive tool with which to dissect terrestrial ecosystem response to changing Southern Ocean conditions during the Cenozoic.", "keyphrases": ["cenozoic", "patagonia", "vegetation", "phytolith", "eocene"]}
{"id": "paleo.008566", "title": "A New Rhynchocephalian from the Late Jurassic of Germany with a Dentition That Is Unique amongst Tetrapods", "abstract": "Background Rhynchocephalians, the sister group of squamates (lizards and snakes), are only represented by the single genus Sphenodon today. This taxon is often considered to represent a very conservative lineage. However, rhynchocephalians were common during the late Triassic to latest Jurassic periods, but rapidly declined afterwards, which is generally attributed to their supposedly adaptive inferiority to squamates and/or Mesozoic mammals, which radiated at that time. New finds of Mesozoic rhynchocephalians can thus provide important new information on the evolutionary history of the group. Principle Findings A new fossil relative of Sphenodon from the latest Jurassic of southern Germany, Oenosaurus muehlheimensis gen. et sp. nov., presents a dentition that is unique amongst tetrapods. The dentition of this taxon consists of massive, continuously growing tooth plates, probably indicating a crushing dentition, thus representing a previously unknown trophic adaptation in rhynchocephalians. Conclusions/Significance The evolution of the extraordinary dentition of Oenosaurus from the already highly specialized Zahnanlage generally present in derived rhynchocephalians demonstrates an unexpected evolutionary plasticity of these animals. Together with other lines of evidence, this seriously casts doubts on the assumption that rhynchocephalians are a conservative and adaptively inferior lineage. Furthermore, the new taxon underlines the high morphological and ecological diversity of rhynchocephalians in the latest Jurassic of Europe, just before the decline of this lineage on this continent. Thus, selection pressure by radiating squamates or Mesozoic mammals alone might not be sufficient to explain the demise of the clade in the Late Mesozoic, and climate change in the course of the fragmentation of the supercontinent of Pangaea might have played a major role.", "keyphrases": ["dentition", "tetrapod", "sphenodon", "late triassic", "mesozoic rhynchocephalian"]}
{"id": "paleo.002514", "title": "Neoichnology of tarantulas (Araneae: Theraphosidae): Criteria for recognizing spider burrows in the fossil record", "abstract": "The Mygalomorphae, a suborder of heavy bodied spiders that includes tarantulas, first appears in the Triassic. While burrowing is common among extant mygalomorphs, fossil burrows attributable to this group are not well-documented. The goal of this study is to describe the morphology of tarantula burrows and to compare them to the burrows of other large, terrestrial animals with the purpose of improving the interpretation of continental ichnofossils and ancient soil ecosystems. This project involved the study of the burrowing behaviors and burrow morphologies of Hysterocrates gigas, Pelinobius muticus, and Aphonopelma chalcodes (Araneae: Theraphosidae), which inhabit tropical to subtropical forests, scrublands and grasslands, and semi-arid deserts, respectively. Individual tarantulas were placed in sediment-filled terrariums under controlled temperature and moisture conditions according to their environmental preferences. The tarantulas were observed for three to 12 months after which they were removed, and the open burrows were cast with plaster, excavated, and described. Each species constructed burrows by excavating sediment using their chelicerae and pedipalps. Burrow openings were circular to elliptical and lined with thin layers of silk. The tarantulas produced burrows with distinct morphologies: 1) H. gigas: vertical shafts with elongate ovoid chambers near the sediment surface and at depth, 2) P. muticus: subvertical sinuous shafts with and without branches, and 3) A. chalcodes: straight to curved, subhorizontal tunnels. Tarantula burrows as a group were also distinct from burrows of trapdoor spiders, scorpions, salamanders, and skinks. Data collected from these neoichnological studies can be applied to continental ichnofossil assemblages in order to better interpret the paleoecology of ancient soil ecosystems.", "keyphrases": ["tarantula", "araneae", "hysterocrates gigas", "aphonopelma chalcode"]}
{"id": "10.1073/pnas.1106759108", "title": "Timing of the appearance of habitual fire use", "abstract": "Using a number of Middle and Late Pleistocene sites with good evidence for fire, Roebroeks and Villa (1) argued that the habitual use of fire did not become part of hominin technological repertoires until the latter half of the Middle Pleistocene. We are pleased to see other researchers taking a more critical view of the nature and quality of the available evidence for early fire use and questioning what seems to be a long-held assumption that the earliest evidence for fire use marks the point at which it becomes inextricably part of hominin adaptations (2, 3). We agree that the evidence indicates that fire was not a requisite technology that allowed Early Pleistocene hominins to expand into more northerly latitudes. However, we argue that the available evidence better supports a significantly later appearance for the habitual use of fire (sometime near the end of the Late Pleistocene) and that before this fire, use was always sporadic and opportunistic. Roebroeks and Villa (1) supported their argument by showing, in figure 1 and table 1 in ref. 1, significant increases in the numbers of sites with good evidence for fire in the more recent Marine Isotope Stages (MIS), and they adjusted these data to show numbers of sites with good evidence for fire per 10,000-y increment within each MIS. A potential problem with these data is that they may simply be reflecting the overall frequency of sites per time period. We can expect that, because of ongoing taphonomic processes, there will necessarily be fewer sites the farther back in time we look. It would be more meaningful if we look at the number of site occupations with good evidence for fire relative to the total number of site occupations known for that specific time period. This finding would provide a much better indication of any changes in the frequency of fire use during the Pleistocene and perhaps indicate when fire use stopped being sporadic and became habitual. Our own work (4, 5), which includes a strong control on taphonomic factors in the visibility of fire use, clearly indicates that, as late as mid-MIS 3, Neandertals were rarely using fire during main occupations of (at least some) cave sites in Southwestern France. Specifically, at Pech de l'Aze IV and Roc de Marsal (Dordogne, France), well-preserved hearths are evident in levels associated with warm climatic conditions, but in levels associated with cold environments (MIS 4 and 3), evidence for fire is almost nonexistent, although concentrations of lithics and butchered faunal remains are high. The fact that this finding reflects a lack of fire use is best supported by frequencies of burned flints throughout the site sequences, although these data are directly paralleled by frequencies of more ephemeral fire residues (burned bone, charcoal, and ash). We would argue that, if Neandertals had the ability to make fire at will, then evidence for it should occur with much greater frequency in Middle Paleolithic sites and occupations and especially, those sites associated with such cold stages.", "keyphrases": ["fire use", "mis", "occupation", "southwestern france"]}
{"id": "10.1073/pnas.1421707112", "title": "Oldest known euarchontan tarsals and affinities of Paleocene Purgatorius to Primates", "abstract": "Significance Purgatorius has been considered a plausible ancestor for primates since it was discovered, but this fossil mammal has been known only from teeth and jaw fragments. We attribute to Purgatorius the first (to our knowledge) nondental remains (ankle bones) which were discovered in the same \u223c65-million-year-old deposits as dentitions of this putative primate. This attribution is based mainly on size and unique anatomical specializations known among living euarchontan mammals (primates, treeshrews, colugos) and fossil plesiadapiforms. Results of phylogenetic analyses that incorporate new data from these fossils support Purgatorius as the geologically oldest known primate. These recently discovered tarsals have specialized features for mobility and provide the oldest fossil evidence that suggests arboreality played a key role in earliest primate evolution. Earliest Paleocene Purgatorius often is regarded as the geologically oldest primate, but it has been known only from fossilized dentitions since it was first described half a century ago. The dentition of Purgatorius is more primitive than those of all known living and fossil primates, leading some researchers to suggest that it lies near the ancestry of all other primates; however, others have questioned its affinities to primates or even to placental mammals. Here we report the first (to our knowledge) nondental remains (tarsal bones) attributed to Purgatorius from the same earliest Paleocene deposits that have yielded numerous fossil dentitions of this poorly known mammal. Three independent phylogenetic analyses that incorporate new data from these fossils support primate affinities of Purgatorius among euarchontan mammals (primates, treeshrews, and colugos). Astragali and calcanei attributed to Purgatorius indicate a mobile ankle typical of arboreal euarchontan mammals generally and of Paleocene and Eocene plesiadapiforms specifically and provide the earliest fossil evidence of arboreality in primates and other euarchontan mammals. Postcranial specializations for arboreality in the earliest primates likely played a key role in the evolutionary success of this mammalian radiation in the Paleocene.", "keyphrases": ["purgatorius", "primate", "plesiadapiform"]}
{"id": "10.1093/sysbio/syp079", "title": "Tinamous and moa flock together: mitochondrial genome sequence analysis reveals independent losses of flight among ratites.", "abstract": "Ratites are large, flightless birds and include the ostrich, rheas, kiwi, emu, and cassowaries, along with extinct members, such as moa and elephant birds. Previous phylogenetic analyses of complete mitochondrial genome sequences have reinforced the traditional belief that ratites are monophyletic and tinamous are their sister group. However, in these studies ratite monophyly was enforced in the analyses that modeled rate heterogeneity among variable sites. Relaxing this topological constraint results in strong support for the tinamous (which fly) nesting within ratites. Furthermore, upon reducing base compositional bias and partitioning models of sequence evolution among protein codon positions and RNA structures, the tinamou-moa clade grouped with kiwi, emu, and cassowaries to the exclusion of the successively more divergent rheas and ostrich. These relationships are consistent with recent results from a large nuclear data set, whereas our strongly supported finding of a tinamou-moa grouping further resolves palaeognath phylogeny. We infer flight to have been lost among ratites multiple times in temporally close association with the Cretaceous-Tertiary extinction event. This circumvents requirements for transient microcontinents and island chains to explain discordance between ratite phylogeny and patterns of continental breakup. Ostriches may have dispersed to Africa from Eurasia, putting in question the status of ratites as an iconic Gondwanan relict taxon.", "keyphrases": ["flight", "ratite", "kiwi", "elephant bird"]}
{"id": "paleo.001659", "title": "Hypsodonty in Pleistocene ground sloths", "abstract": "Although living sloths (Xenarthra, Tardigrada) are represented by only two genera, their fossil relatives form a large and diverse group. The evolution of hypsodonty, the crown height of a tooth, has traditionally been viewed as a response to dietary shifts toward abrasive vegetation. But recent work indicates that hypsodonty is also due to the higher prevalence of grit and dust in more open environments. The teeth of sloths are both high-crowned and open-rooted, or hypselodont, but distinctions between the selective factors acting to produce differing degrees of hypsodonty have not been rigorously considered. A comparative analysis of hypsodonty was performed in eleven species of Pleistocene sloths. It suggests that differences in hypsodonty may be explained by dietary preferences, habitat and habits. Among mylodontids, morphologic and biomechanical analyses indicate that hypsodonty was unlikely to be due solely to feeding behavior, such as grazing. Some mylodontids (e.g., Scelidotherium leptocephalum, Lestodon armatus, Glossotherium robustum, Mylodon darwini) were capable diggers that likely dug for food, and ingestion of abrasive soil particles probably played a considerable role in shaping their dental characteristics. Increased hypsodonty over time in Paramylodon harlani, however, is apparently due to a change in habitat from closed to more open environments. Geographical distributions of the megatheriids Eremotherium and Megatherium indicate differing habitats as possible factors in hypsodonty differences. In summary, among Tardigrada hypsodonty is apparently affected by diet, habitat and habit. The absence of enamel must be responsible for much of the hypsodonty observed in xenarthrans, which obscures the interpretation of contribution of each of the mentioned factors.", "keyphrases": ["pleistocene ground sloth", "xenarthra", "mylodontid", "enamel"]}
{"id": "paleo.011456", "title": "The Evolution and Development of Cephalopod Chambers and Their Shape", "abstract": "The Ammonoidea is a group of extinct cephalopods ideal to study evolution through deep time. The evolution of the planispiral shell and complexly folded septa in ammonoids has been thought to have increased the functional surface area of the chambers permitting enhanced metabolic functions such as: chamber emptying, rate of mineralization and increased growth rates throughout ontogeny. Using nano-computed tomography and synchrotron radiation based micro-computed tomography, we present the first study of ontogenetic changes in surface area to volume ratios in the phragmocone chambers of several phylogenetically distant ammonoids and extant cephalopods. Contrary to the initial hypothesis, ammonoids do not possess a persistently high relative chamber surface area. Instead, the functional surface area of the chambers is higher in earliest ontogeny when compared to Spirula spirula. The higher the functional surface area the quicker the potential emptying rate of the chamber; quicker chamber emptying rates would theoretically permit faster growth. This is supported by the persistently higher siphuncular surface area to chamber volume ratio we collected for the ammonite Amauroceras sp. compared to either S. spirula or nautilids. We demonstrate that the curvature of the surface of the chamber increases with greater septal complexity increasing the potential refilling rates. We further show a unique relationship between ammonoid chamber shape and size that does not exist in S. spirula or nautilids. This view of chamber function also has implications for the evolution of the internal shell of coleoids, relating this event to the decoupling of soft-body growth and shell growth.", "keyphrases": ["cephalopod", "ammonoid", "ontogenetic change", "spirula spirula", "septal spacing"]}
{"id": "paleo.013126", "title": "Ecological Interactions in Dinosaur Communities: Influences of Small Offspring and Complex Ontogenetic Life Histories", "abstract": "Because egg-laying meant that even the largest dinosaurs gave birth to very small offspring, they had to pass through multiple ontogenetic life stages to adulthood. Dinosaurs\u2019 successors as the dominant terrestrial vertebrate life form, the mammals, give birth to live young, and have much larger offspring and less complex ontogenetic histories. The larger number of juveniles in dinosaur as compared to mammal ecosystems represents both a greater diversity of food available to predators, and competitors for similar-sized individuals of sympatric species. Models of population abundances across different-sized species of dinosaurs and mammals, based on simulated ecological life tables, are employed to investigate how differences in predation and competition pressure influenced dinosaur communities. Higher small- to medium-sized prey availability leads to a normal body mass-species richness (M-S) distribution of carnivorous dinosaurs (as found in the theropod fossil record), in contrast to the right-skewed M-S distribution of carnivorous mammals (as found living members of the order Carnivora). Higher levels of interspecific competition leads to a left-skewed M-S distribution in herbivorous dinosaurs (as found in sauropods and ornithopods), in contrast to the normal M-S distribution of large herbivorous mammals. Thus, our models suggest that differences in reproductive strategy, and consequently ontogeny, explain observed differences in community structure between dinosaur and mammal faunas. Models also show that the largest dinosaurian predators could have subsisted on similar-sized prey by including younger life stages of the largest herbivore species, but that large predators likely avoided prey much smaller than themselves because, despite predicted higher abundances of smaller than larger-bodied prey, contributions of small prey to biomass intake would be insufficient to satisfy meat requirements. A lack of large carnivores feeding on small prey exists in mammals larger than 21.5 kg, and it seems a similar minimum prey-size threshold could have affected dinosaurs as well.", "keyphrases": ["small offspring", "herbivorous dinosaur", "strategy", "ontogeny", "large dinosaur"]}
{"id": "paleo.008074", "title": "Soft-tissue and dermal arrangement in the wing of an Early Cretaceous bird: Implications for the evolution of avian flight", "abstract": "Despite a wealth of fossils of Mesozoic birds revealing evidence of plumage and other soft-tissue structures, the epidermal and dermal anatomy of their wing\u2019s patagia remain largely unknown. We describe a distal forelimb of an enantiornithine bird from the Lower Cretaceous limestones of Las Hoyas, Spain, which reveals the overall morphology of the integument of the wing and other connective structures associated with the insertion of flight feathers. The integumentary anatomy, and myological and arthrological organization of the new fossil is remarkably similar to that of modern birds, in which a system of small muscles, tendons and ligaments attaches to the follicles of the remigial feathers and maintains the functional integrity of the wing during flight. The new fossil documents the oldest known occurrence of connective tissues in association with the flight feathers of birds. Furthermore, the presence of an essentially modern connective arrangement in the wing of enantiornithines supports the interpretation of these primitive birds as competent fliers.", "keyphrases": ["arrangement", "wing", "plumage", "feather", "tissue"]}
{"id": "paleo.012432", "title": "Pterosaur dietary hypotheses: a review of ideas and approaches", "abstract": "Pterosaurs are an extinct group of Mesozoic flying reptiles, whose fossil record extends from approximately 210 to 66 million years ago. They were integral components of continental and marginal marine ecosystems, yet their diets remain poorly constrained. Numerous dietary hypotheses have been proposed for different pterosaur groups, including insectivory, piscivory, carnivory, durophagy, herbivory/frugivory, filter\u2010feeding and generalism. These hypotheses, and subsequent interpretations of pterosaur diet, are supported by qualitative (content fossils, associations, ichnology, comparative anatomy) and/or quantitative (functional morphology, stable isotope analysis) evidence. Pterosaur dietary interpretations are scattered throughout the literature with little attention paid to the supporting evidence. Reaching a robustly supported consensus on pterosaur diets is important for understanding their dietary evolution, and their roles in Mesozoic ecosystems. A comprehensive examination of the pterosaur literature identified 314 dietary interpretations (dietary statement plus supporting evidence) from 126 published studies. Multiple alternative diets have been hypothesised for most principal taxonomic pterosaur groups. Some groups exhibit a high degree of consensus, supported by multiple lines of evidence, while others exhibit less consensus. Qualitative evidence supports 87.3% of dietary interpretations, with comparative anatomy most common (62.1% of total). More speciose groups of pterosaur tend to have a greater range of hypothesised diets. Consideration of dietary interpretations within alternative phylogenetic contexts reveals high levels of consensus between equivalent monofenestratan groups, and lower levels of consensus between equivalent non\u2010monofenestratan groups. Evaluating the possible non\u2010biological controls on apparent patterns of dietary diversity reveals that numbers of dietary interpretations through time exhibit no correlation with patterns of publication (number of peer\u2010reviewed publications through time). 73.8% of dietary interpretations were published in the 21st century. Overall, consensus interpretations of pterosaur diets are better accounted for by non\u2010biological signals, such as the impact of the respective quality of the fossil record of different pterosaur groups on research levels. That many interpretations are based on qualitative, often untestable lines of evidence adds significant noise to the data. More experiment\u2010led pterosaur dietary research, with greater consideration of pterosaurs as organisms with independent evolutionary histories, will lead to more robust conclusions drawn from repeatable results. This will allow greater understanding of pterosaur dietary diversity, disparity and evolution and facilitate reconstructions of Mesozoic ecosystems.", "keyphrases": ["pterosaur group", "content fossil", "consensus", "dietary hypothesis", "food webs"]}
{"id": "paleo.011982", "title": "Hoplitolyda duolunica gen. et sp. nov. (Insecta, Hymenoptera, Praesiricidae), the Hitherto Largest Sawfly from the Mesozoic of China", "abstract": "Background Large body size of an insect, in general, enhances its capability of predation, competition, and defense, resulting in better survivability and reproduction. Hymenopterans, most being phytophagous or parasitic, have a relatively small to medium body size, typically under 50.0 mm in body length. Principal Findings Herein, we describe Hoplitolyda duolunica gen. et sp. nov., assigned to Praesiricidae, from the Early Cretaceous Yixian Formation of China. This new species is the largest fossil hymenopteran hitherto with body estimated >55.0 mm long and wing span >92.0 mm. H. duolunica is, to our knowledge, the only sawfly with Sc present in the hind wing but not in the forewing. Its Rs1 and M1 meeting each other at 145\u00b0 angle represents an intermediate in the transition from \u201cY\u201d to \u201cT\u201d shapes. Even though Hoplitolyda differs significantly from all previously described genera in two subfamilies of Praesricidae, we leave the new genus unplaced in existing subfamilies, pending discovery of material with more taxonomic structure. Conclusions/Significance Hoplitolyda has many unique and interesting characters which might have benefitted its competition, survival, and reproduction: large body size and head with robust and strong mandibles for defense and/or sexual selection, unique wing venation and setal arrangements for flight capability and mobility, dense hairs on body and legs for sensing and protection, etc. Considering the reported ferocious predators of feathered dinosaurs, pterosaurs, birds, and mammals coexisting in the same eco-system, Hoplitolyda is an interesting case of \u201csurvival of the fittest\u201d in facing its evolutionary challenges.", "keyphrases": ["praesiricidae", "china", "body length", "wing span"]}
{"id": "10.1111/brv.12276", "title": "The geometry of morphospaces: lessons from the classic Raup shell coiling model", "abstract": "Morphospaces are spatial depictions of morphological variation among biological forms that have become an integral part of the analytical toolkit of evolutionary biologists and palaeobiologists. Nevertheless, the term morphospace brings together a great variety of spaces with different geometries. In particular, many morphospaces lack the metric properties underlying the notions of distance and direction, which are, however, central to the analysis of morphological differences and evolutionary transitions. The problem is illustrated here with the iconic morphospace of coiled shells implemented by Raup 50\u2009years ago. The model, which allows the description of shell coiling geometry of various invertebrate taxa, is a seminal reference in theoretical morphology and morphospace theory, but also a morphometric framework frequently used in empirical studies, particularly of ammonoids. Because of the definition of its underlying parameters, Raup's morphospace does not possess a Euclidean structure and a meaningful interpretation of the spread and spacing of taxa within it is not guaranteed. Focusing on the region of the morphospace occupied by most ammonoids, I detail a landmark\u2010based morphospace circumventing this problem and built from the same input measurements required for the calculation of Raup's parameters. From simulations and a reanalysis of Palaeozoic ammonoid shell disparity, the properties of these morphospaces are compared and their algebraic and geometric relationships highlighted. While Raup's model remains a valuable tool for describing ammonoid shells and relating their shapes to the coiling process, it is demonstrated that quantitative analyses of morphological patterns should be carried out within the landmark\u2010based framework. Beyond this specific case, the increasing use and diversity of morphospaces in evolutionary morphology call for caution when interpreting patterns and comparing results drawn from different types of morphospaces.", "keyphrases": ["morphospace", "ammonoid", "tool", "cephalopod"]}
{"id": "10.2517/2017PR013", "title": "Euroxenomys nanus sp. nov., a Minute Beaver (Rodentia, Castoridae) from the Early Miocene of Japan", "abstract": "Abstract. \n A recently discovered, incomplete dentary with preserved incisor, premolar and first molar of a minute castorid from the Dota locality, Kani Basin, early Miocene (ca. 18.5 Ma) Nakamura Formation of the Mizunami Group in central Japan, is described as a new species of the trogontheriine beaver Euroxenomys. It represents the first record of Euroxenomys in Asia and one of the oldest records of this genus. Euroxenomys nanus sp. nov. is smaller than the type species, E. minutus from the Miocene of Europe and more hypsodont, but similar in size to E. inconnexus from the Barstovian of Montana. Dota is the first Asian locality with three cooccurring castorids, Youngofiber sinensis, Minocastor godai, and E. nanus.", "keyphrases": ["early miocene", "large-sized minocastor godai", "monosaulax tungurensis"]}
{"id": "10.1111/evo.12684", "title": "A molecular mechanism for the origin of a key evolutionary innovation, the bird beak and palate, revealed by an integrative approach to major transitions in vertebrate history", "abstract": "The avian beak is a key evolutionary innovation whose flexibility has permitted birds to diversify into a range of disparate ecological niches. We approached the problem of the mechanism behind this innovation using an approach bridging paleontology, comparative anatomy, and experimental developmental biology. First, we used fossil and extant data to show the beak is distinctive in consisting of fused premaxillae that are geometrically distinct from those of ancestral archosaurs. To elucidate underlying developmental mechanisms, we examined candidate gene expression domains in the embryonic face: the earlier frontonasal ectodermal zone (FEZ) and the later midfacial WNT\u2010responsive region, in birds and several reptiles. This permitted the identification of an autapomorphic median gene expression region in Aves. To test the mechanism, we used inhibitors of both pathways to replicate in chicken the ancestral amniote expression. Altering the FEZ altered later WNT responsiveness to the ancestral pattern. Skeletal phenotypes from both types of experiments had premaxillae that clustered geometrically with ancestral fossil forms instead of beaked birds. The palatal region was also altered to a more ancestral phenotype. This is consistent with the fossil record and with the tight functional association of avian premaxillae and palate in forming a kinetic beak.", "keyphrases": ["evolutionary innovation", "beak", "developmental biology"]}
{"id": "10.1144/SP427.11", "title": "Late Eocene palaeogeography of the proto-Paratethys Sea in Central Asia (NW China, southern Kyrgyzstan and SW Tajikistan)", "abstract": "Abstract The Cretaceous and Palaeogene sediments of the basins in Central Asia include the remnants of the easternmost extent of a vast shallow epicontinental sea, which extended across the Eurasian continent before it retreated westwards and eventually isolated as the Paratethys Sea. To improve understanding of its long-term palaeogeographical evolution, we complement the well-constrained chronological framework of the Tarim Basin in China with stratigraphic records of the sea retreat from the Fergana Basin and the Alai Valley Basin in southern Kyrgyzstan and the Afghan\u2013Tajik Basin in SW Tajikistan. By lithostratigraphic analyses and identification of bivalve assemblages, this study establishes for the first time a clear and detailed regional correlation of Palaeogene marine strata across Central Asia, showing that the basins share a similar palaeogeographical evolution characterized by a long-term stepwise retreat punctuated by short-term shallow-marine incursions. Our correlation shows that the last two marine incursions recognized in the Tarim Basin can be traced westwards. The permanent disappearance of the sea from Central Asia probably occurred with limited diachroneity in the late Eocene, before the isolation of the Paratethys Sea, shifting the easternmost margin of the sea hundreds of kilometres westwards and probably significantly reducing moisture supply to the Asian interior.", "keyphrases": ["southern kyrgyzstan", "fergana basin", "marine incursion"]}
{"id": "paleo.012372", "title": "Phylogeny of Dictyoptera: Dating the Origin of Cockroaches, Praying Mantises and Termites with Molecular Data and Controlled Fossil Evidence", "abstract": "Understanding the origin and diversification of organisms requires a good phylogenetic estimate of their age and diversification rates. This estimate can be difficult to obtain when samples are limited and fossil records are disputed, as in Dictyoptera. To choose among competing hypotheses of origin for dictyopteran suborders, we root a phylogenetic analysis (~800 taxa, 10 kbp) within a large selection of outgroups and calibrate datings with fossils attributed to lineages with clear synapomorphies. We find the following topology: (mantises, (other cockroaches, (Cryptocercidae, termites)). Our datings suggest that crown-Dictyoptera\u2014and stem-mantises\u2014would date back to the Late Carboniferous (~ 300 Mya), a result compatible with the oldest putative fossil of stem-dictyoptera. Crown-mantises, however, would be much more recent (~ 200 Mya; Triassic/Jurassic boundary). This pattern (i.e., old origin and more recent diversification) suggests a scenario of replacement in carnivory among polyneopterous insects. The most recent common ancestor of (cockroaches + termites) would date back to the Permian (~275 Mya), which contradicts the hypothesis of a Devonian origin of cockroaches. Stem-termites would date back to the Triassic/Jurassic boundary, which refutes a Triassic origin. We suggest directions in extant and extinct species sampling to sharpen this chronological framework and dictyopteran evolutionary studies.", "keyphrases": ["dictyoptera", "diversification", "triassic", "insect"]}
{"id": "10.7717/peerj.3022", "title": "Eotaria citrica, sp. nov., a new stem otariid from the \u201cTopanga\u201d formation of Southern California", "abstract": "A new taxon of stem otariid, Eotaria citrica sp. nov., is described from the upper Burdigalian to lower Langhian \u201cTopanga\u201d formation of Orange County, California. The new species is described from mandibular and dental remains that show a unique combination of plesiomorphic and derived characters. Specifically, it is characterized by having trenchant and prominent paraconid cusps in p3\u2013m1, lingual cingula of p2\u20134 with faint crenulations, premolars and molars with vestigial metaconid, bilobed root of m2 and a genial tuberosity located under p3. Furthermore, additional material of the contemporaneous Eotaria crypta is described, providing new information on the morphology of this taxon. Both species of Eotaria represent the earliest stem otariids, reinforcing the hypothesis that the group originated in the north Eastern Pacific Region. At present, the \u201cTopanga\u201d Fm. pinniped fauna includes Eotaria citrica, Eotaria crypta, the desmatophocid Allodesmus sp., the odobenids Neotherium sp., Pelagiarctos sp. and includes the oldest records of crown pinnipeds in California. Overall this pinniped fauna is similar to the nearly contemporaneous Sharktooth Hill bonebed. However, unambiguous records of Eotaria are still missing from Sharktooth Hill. This absence may be due to taphonomic or paleoenvironmental factors. The new \u201cTopanga\u201d record presented here was integrated into an overview of the late Oligocene through early Pleistocene pinniped faunas of Southern California. The results show an overall increase in body size over time until the Pleistocene. Furthermore, desmatophocids were the largest pinnipeds during the middle Miocene, but were extinct by the beginning of the late Miocene. Odobenids diversified and became the dominant pinnipeds in late Miocene through Pleistocene assemblages, usually approaching or exceeding 3 m in body length, while otariids remained as the smallest taxa. This pattern contrasts with modern assemblages, in which the phocid Mirounga angustirostris is the largest pinniped taxon in the region, odobenids are extinct and medium and small size ranges are occupied by otariids or other phocids.", "keyphrases": ["southern california", "crown pinniped", "late oligocene", "eotaria citrica"]}
{"id": "10.1017/S009483730001650X", "title": "Prey selection by terrestrial carnivores in a lower Pleistocene paleocommunity", "abstract": "We report quantitative paleoecologic data on the large mammal assemblage preserved in lower Pleistocene deposits at Venta Micena (Orce, Granada, southeastern Spain). Taphonomic studies show that bones were collected mainly by hyaenids, which transported and deposited them near shallow dens. Differential fragmentation of major long bones was produced by hyaenas as a function of their density and marrow content. Strong selection of prey by carnivores\u2014which preferentially killed juveniles, females, and individuals with diminished locomotor capabilities among ungulate prey species of larger body size\u2014is indicated by (1) the abundance of remains of juvenile ungulates in relation to the average weight of adult individuals in each species, (2) attritional mortality profiles for ungulate species deduced from crown height measurements, (3) the presence of many metapodials with different osteopathologies in their epiphyses, such as arthrosis, and (4) a biased intersexual ratio of large bovids. Comparison of the frequencies with which modern African carnivores kill and scavenge ungulates from various size classes with the abundance of these size categories in the assemblage suggests that the Venta Micena hyaena (Pachycrocuta brevirostris) was a bone-cracking scavenger that fed largely on carcasses of ungulates preyed upon and partially consumed by fresh meat-eating carnivores such us saber-toothed felids (Homotherium latidens and Megantereon whitei) and wild dogs (Canis falconeri).", "keyphrases": ["carnivore", "carcass", "felid"]}
{"id": "10.1093/sysbio/syv115", "title": "Geomolecular Dating and the Origin of Placental Mammals.", "abstract": "In modern evolutionary divergence analysis the role of geological information extends beyond providing a timescale, to informing molecular rate variation across the tree. Here I consider the implications of this development. I use fossil calibrations to test the accuracy of models of molecular rate evolution for placental mammals, and reveal substantial misspecification associated with life history rate correlates. Adding further calibrations to reduce dating errors at specific nodes unfortunately tends to transfer underlying rate errors to adjacent branches. Thus, tight calibration across the tree is vital to buffer against rate model errors. I argue that this must include allowing maximum bounds to be tight when good fossil records permit, otherwise divergences deep in the tree will tend to be inflated by the interaction of rate errors and asymmetric confidence in minimum and maximum bounds. In the case of placental mammals I sought to reduce the potential for transferring calibration and rate model errors across the tree by focusing on well-supported calibrations with appropriately conservative maximum bounds. The resulting divergence estimates are younger than others published recently, and provide the long-anticipated molecular signature for the placental mammal radiation observed in the fossil record near the 66 Ma Cretaceous-Paleogene extinction event.", "keyphrases": ["divergence", "timescale", "calibration", "age estimate"]}
{"id": "10.1098/rspb.2016.2839", "title": "Surrogate taxa and fossils as reliable proxies of spatial biodiversity patterns in marine benthic communities", "abstract": "Rigorous documentation of spatial heterogeneity (\u03b2-diversity) in present-day and preindustrial ecosystems is required to assess how marine communities respond to environmental and anthropogenic drivers. However, the overwhelming majority of contemporary and palaeontological assessments have centred on single higher taxa. To evaluate the validity of single taxa as community surrogates and palaeontological proxies, we compared macrobenthic communities and sympatric death assemblages at 52 localities in Onslow Bay (NC, USA). Compositional heterogeneity did not differ significantly across datasets based on live molluscs, live non-molluscs, and all live organisms. Death assemblages were less heterogeneous spatially, likely reflecting homogenization by time-averaging. Nevertheless, live and dead datasets were greater than 80% congruent in pairwise comparisons to the literature estimates of \u03b2-diversity in other marine ecosystems, yielded concordant bathymetric gradients, and produced nearly identical ordinations consistently delineating habitats. Congruent estimates from molluscs and non-molluscs suggest that single groups can serve as reliable community proxies. High spatial fidelity of death assemblages supports the emerging paradigm of Conservation Palaeobiology. Integrated analyses of ecological and palaeontological data based on surrogate taxa can quantify anthropogenic changes in marine ecosystems and advance our understanding of spatial and temporal aspects of biodiversity.", "keyphrases": ["\u03b2-diversity", "death assemblage", "anthropogenic change", "surrogate taxa"]}
{"id": "10.1029/2018PA003482", "title": "The Middle to Late Miocene \u201cCarbonate Crash\u201d in the Equatorial Indian Ocean", "abstract": "We integrate benthic foraminiferal stable isotopes, X\u2010ray fluorescence elemental ratios, and carbonate accumulation estimates in a continuous sedimentary archive recovered at International Ocean Discovery Program Site U1443 (Ninetyeast Ridge, Indian Ocean) to reconstruct changes in carbonate deposition and climate evolution over the interval 13.5 to 8.2 million years ago. Declining carbonate percentages together with a marked decrease in carbonate accumulation rates after ~13.2 Ma signal the onset of a prolonged episode of reduced carbonate deposition. This extended phase, which lasted until ~8.7 Ma, coincides with the middle to late Miocene carbonate crash, originally identified in the eastern equatorial Pacific Ocean and the Caribbean Sea. Interocean comparison reveals that intense carbonate impoverishment at Site U1443 (~11.5 to ~10 Ma) coincides with prolonged episodes of reduced carbonate deposition in all major tropical ocean basins. This implies that global changes in the intensity of chemical weathering and riverine input of calcium and carbonate ions into the ocean reservoir were instrumental in driving the carbonate crash. An increase in U1443 Log (Ba/Ti) together with a change in sediment color from red to green indicate a rise in organic export flux to the sea floor after ~11.2 Ma, which predates the global onset of the biogenic bloom. This early rise in export flux from biological production may have been linked to increased advection of nutrients and intensification of upper ocean mixing, associated with changes in the seasonality and intensity of the Indian Monsoon.", "keyphrases": ["carbonate crash", "indian ocean", "miocene carbonate crash", "sediment color"]}
{"id": "10.1098/rspb.2012.0445", "title": "Historical pesticide applications coincided with an altered diet of aerially foraging insectivorous chimney swifts", "abstract": "Numerous environmental pressures have precipitated long-term population reductions of many insect species. Population declines in aerially foraging insectivorous birds have also been detected, but the cause remains unknown partly because of a dearth of long-term monitoring data on avian diets. Chimney swifts (Chaetura pelagica) are a model aerial insectivore to fill such information gaps because their roosting behaviour makes them easy to sample in large numbers over long time periods. We report a 48-year-long (1944\u20131992) dietary record for the chimney swift, determined from a well-preserved deposit of guano and egested insect remains in Ontario (Canada). This unique archive of palaeo-environmental data reflecting past chimney swift diets revealed a steep rise in dichlorodiphenyltrichloroethane (DDT) and metabolites, which were correlated with a decrease in Coleoptera remains and an increase in Hemiptera remains, indicating a significant change in chimney swift prey. We argue that DDT applications decimated Coleoptera populations and dramatically altered insect community structure by the 1960s, triggering nutritional consequences for swifts and other aerial insectivores.", "keyphrases": ["insectivore", "chimney swift", "chaetura pelagica"]}
{"id": "paleo.004185", "title": "Near\u2010Future pCO2 During the Hot Miocene Climatic Optimum", "abstract": "To improve future predictions of anthropogenic climate change, a better understanding of the relationship between global temperature and atmospheric concentrations of CO2 (pCO2), or climate sensitivity, is urgently required. Analyzing proxy data from climate change episodes in the past is necessary to achieve this goal, with certain geologic periods, such as the Miocene climatic optimum (MCO), a transient period of global warming with global temperatures up to ~7\u00b0C higher than today, increasingly viewed as good analogues to future climate under present emission scenarios. However, a problem remains that climate models cannot reproduce MCO temperatures with less than ~800 ppm pCO2, while most previously published proxies record pCO2 < 450 ppm. Here, we reconstructed MCO pCO2 with a multitaxon fossil leaf database from the well\u2010dated MCO Lagerst\u00e4tte deposits of Clarkia, Idaho, USA, using four current methods of pCO2 reconstructions. The methods are principally based on either stomatal densities, carbon isotopes, or a combination of both\u2014thus offering independent results. The total of six reconstructions mostly record pCO2 of ~450\u2013550 ppm. Although slightly higher than previously reconstructed pCO2, the discrepancy with the ~800 ppm required by climate models remains. We conclude that climate sensitivity was heightened during MCO, indicating that highly elevated temperatures can occur at relatively moderate pCO2. Ever higher climate sensitivity with rising temperatures should be very seriously considered in future predictions of climate change.", "keyphrases": ["pco2", "concentration", "stomatal density"]}
{"id": "10.1080/03014223.2012.665060", "title": "Twenty-first century advances in knowledge of the biology of moa (Aves: Dinornithiformes): a new morphological analysis and moa diagnoses revised", "abstract": "Abstract The iconic moa (Aves: Dinornithiformes) from New Zealand continue to attract much scientific scrutiny, as they have done since their discovery in the 1840s. Here, we review moa research since 2001 that advances our knowledge of the biology of these families; in particular, their breeding, diet and phylogenetic relationships. Then we perform a phylogenetic analysis based on morphological characters using a broader range of taxa and many more characters than hitherto used in moa analyses. Finally, we provide revised diagnoses of all moa taxa to reflect current knowledge. In this last decade, molecular analyses have been at the forefront of much of this research. Indeed, moa have become model subjects for advances in ancient DNA technology on account of their preservation and young geological age, and the fact that several of the foremost proponents of ancient DNA research are New Zealanders. Much of this research has been about extending the capacity of ancient DNA technology as much as about answering biological questions, but the resultant insights with regard to the latter have been profound for moa. Complete mitochondrial genomes for three species of moa have been published and extensive datasets of a number of mitochondrial genes are now available for all species over their entire geographic range. Analyses of nuclear DNA is limited to a sex specific gene and some preliminary microsatellite identifications, but it seems likely that improved technology will allow greater use of this resource in the near future. Phylogenetic analyses of mitochondrial molecular data have precipitated several changes to moa taxonomy and nine species are now recognised. The significance of deep phylogenetic structure among populations in some taxa continues to attract debate and likely will require nuclear data and a more profound understanding of natural variation in extant species to resolve. Significantly, molecular data have enabled new insights into diet, with direct identification of species responsible for coprolites, and by its new-found propensity to identify eggshell, foreshadows further advances in understanding their breeding biology and distribution. Our phylogenetic analysis, based on 179 characters scored for 23 ingroup palaeognath taxa and three galloanseres as outgroups, resulted in several strongly supported relationships. Firstly, the Eocene palaeognath Lithornis was either sister to remaining palaeognaths or had a weak affinity towards tinamous. All ratites formed a monophyletic clade exclusive of tinamous. Moa were monophyletic and sister to aepyornithids in the unconstrained analysis. Attempts to constrain moa as sister to tinamous to reflect molecular-based conclusions resulted in moa as sister to all ratites in a clade that was unresolved with respect to tinamous and Lithornis. This relatively basal position of moa was not a significantly worse reflection of the data compared to their more crownward location in the initial analyses. The casuariids were sister to Struthio and the rheas. In our revised diagnoses for Dinornithiformes and all its constituent taxa, we give updated information on the type specimens based on recent research by the authors. We accept three families, six genera and nine species, and make the new combinations of Euryapteryx curtus curtus (Owen) and E. curtus gravis (Owen). Complete or near complete exemplars of the skull of all moa taxa, most not illustrated before, are shown in dorsal, lateral and ventral views.", "keyphrases": ["biology", "phylogenetic relationship", "reflection", "palaeognath"]}
{"id": "10.1371/journal.pone.0059439", "title": "Phylogenetic Analysis of Thecosomata Blainville, 1824 (Holoplanktonic Opisthobranchia) Using Morphological and Molecular Data", "abstract": "Thecosomata is a marine zooplankton group, which played an important role in the carbonate cycle in oceans due to their shell composition. So far, there is important discrepancy between the previous morphological-based taxonomies, and subsequently the evolutionary history of Thecosomata. In this study, the remarkable planktonic sampling of TARA Oceans expedition associated with a set of various other missions allowed us to assess the phylogenetic relationships of Thecosomata using morphological and molecular data (28 S and COI genes). The two gene trees showed incongruities (e.g. Hyalocylis, Cavolinia), and high congruence between morphological and 28S trees (e.g. monophyly of Euthecosomata). The monophyly of straight shell species led us to reviving the Orthoconcha, and the split of Limacinidae led us to the revival of Embolus inflata replacing Limacina inflata. The results also jeopardized the Euthecosomata families that are based on plesiomorphic character state as in the case for Creseidae which was not a monophyletic group. Divergence times were also estimated, and suggested that the evolutionary history of Thecosomata was characterized by four major diversifying events. By bringing the knowledge of palaeontology, we propose a new evolutionary scenario for which macro-evolution implying morphological innovations were rhythmed by climatic changes and associated species turn-over that spread from the Eocene to Miocene, and were shaped principally by predation and shell buoyancy.", "keyphrases": ["evolutionary scenario", "phylogenetic analysis", "pteropod"]}
{"id": "paleo.006418", "title": "Microbial decay analysis challenges interpretation of putative organ systems in Cambrian fuxianhuiids", "abstract": "The Chengjiang fossil Lagerst\u00e4tte (Cambrian Stage 3) from Yunnan, southern China is renowned for its soft-tissue preservation. Accordingly structures in fuxianhuiids, radiodontans and great appendage arthropods have been interpreted as the nervous and cardiovascular systems, including brains, hearts and blood vessels. That such delicate organ systems survive the fossilization process seems remarkable; given that this mode of preservation involves major taphonomic changes, such as flattening, microbial degradation, chemical alteration and replacement. Here, we document a range of taphonomic preservation states in numerous articulated individuals of Fuxianhuia protensa. We suggest that organic (partly iron mineral-replaced) bulbous structures in the head region, previously interpreted as brain tissue, along with sagittally located organic strands interpreted as part of the cardiovascular system or as nerve cords, may be better explained as microbial biofilms that developed following decomposition of the intestine, muscle and other connective tissues, forming halos surrounding the original organic remains.", "keyphrases": ["organ system", "fuxianhuiid", "tissue"]}
{"id": "10.1130/G33543.1", "title": "Diversity trends in the establishment of terrestrial vertebrate ecosystems: Interactions between spatial and temporal sampling biases", "abstract": "Analyses of how fossil record sampling influences detection of past biodiversity change, and geographic patterns of animal diversity, are central to understanding macroevolution, deep time macroecology, and interactions between the rock and fossil records. The diversification and establishment of complex trophic structure among terrestrial vertebrates (tetrapods) and three hypothesized mass extinctions occurred in the Permian (299.0\u2013252.3 Ma), during a predominantly icehouse global climate regime. Prominent, short-lived features of Permian species diversity curves, such as a possible end-Guadalupian mass extinction, are robust to sampling biases. However, multivariate and time series approaches show that longer term trends in the accumulation of terrestrial biodiversity are more sensitive. Olson\u2019s extinction, believed to have occurred at the end of the Early Permian, might be an artifact of the abrupt geographic shift from predominant sampling of Lower Permian, amphibian-rich, paleotropical everwet biome in North America, to more tetrapod-depauperate Middle\u2013Late Permian, cool paleotemperate biomes in Russia and South America. Thus, geographic heterogeneity in fossil record sampling, superimposed on a prominent, icehouse latitudinal biodiversity gradient, might have created an artifactual macroevolutionary event. This apparent event remains even after correcting data for uneven temporal sampling. Thus, a complex interplay between spatial and temporal biodiversity trends, and geographic and temporal sampling factors, is responsible for generating observed past biodiversity patterns.", "keyphrases": ["establishment", "sampling", "mass extinction"]}
{"id": "10.1126/science.1214697", "title": "Lithium Isotope History of Cenozoic Seawater: Changes in Silicate Weathering and Reverse Weathering", "abstract": "Life of Li Because lithium primarily exists in silicate minerals on continents, the variations of Li isotopes in marine sedimentary rocks reflect the degree of silicate weathering and formation of new sediments on the seafloor, which in turn are largely controlled by climate and tectonic forces over geologic time. By analyzing sedimentary cores from eight drill sites around the world's oceans, Misra and Froelich (p. 818, published online 26 January; see the cover; see the Perspective by Paytan) assembled a 68-million-year record of the Li isotope composition of seawater. The record reveals a stepwise change in the Li isotopic ratio, suggesting that several intense episodes of tectonic uplift increased continental weathering rates and delivery of sediments to the oceans. Abrupt swings in the record at specific points in Earth's history, for example, around the time when dinosaurs became extinct, imply major changes in ocean chemistry\u2014but their mechanisms remain enigmatic. Historical changes in the lithium isotope ratio in seawater imply episodes of tectonic uplift and carbon dioxide drawdown. Weathering of uplifted continental rocks consumes carbon dioxide and transports cations to the oceans, thereby playing a critical role in controlling both seawater chemistry and climate. However, there are few archives of seawater chemical change that reveal shifts in global tectonic forces connecting Earth ocean-climate processes. We present a 68-million-year record of lithium isotopes in seawater (\u03b47LiSW) reconstructed from planktonic foraminifera. From the Paleocene (60 million years ago) to the present, \u03b47LiSW rose by 9 per mil (\u2030), requiring large changes in continental weathering and seafloor reverse weathering that are consistent with increased tectonic uplift, more rapid continental denudation, increasingly incongruent continental weathering (lower chemical weathering intensity), and more rapid CO2 drawdown. A 5\u2030 drop in \u03b47LiSW across the Cretaceous-Paleogene boundary cannot be produced by an impactor or by Deccan trap volcanism, suggesting large-scale continental denudation.", "keyphrases": ["silicate weathering", "planktonic foraminifera", "paleocene", "rapid continental denudation"]}
{"id": "10.1111/j.1096-3642.1990.tb01865.x", "title": "The craniofacial air sac system of Mesozoic birds (Aves)", "abstract": "Birds are characterized by pneumatization of their skeletons by epithelial diverticula from larger, air\u2014filled cavities. The diverticula\u2014or \u2018air sacs\u2019\u2014that invade the postcranium result from outgrowths of the lungs; postcranial pneumaticity has been very well studied. Much more poorly understood are the air sacs that pneumatize the skull. Study of craniofacial pneumaticity in modern birds (Neornithes) indicates the presence of two separate systems: nasal pneumaticity and tympanic pneumaticity. The lacrimal and maxillary bones are pneumatized by diverticula of the main paranasal cavity, the antorbital sinus. There are five tympanic diverticula in neornithines that pneumatic the quadrate, articulare and the bones of the braincase. The pneumatic features of the following six genera of Mesozoic birds are examined: Archaeopteryx, Enaliornis, Baptornis, Parahesperornis, Hesperornis and Ichthyornis. Despite the \u2018archaic\u2019 aspect of most of these birds, many of the pneumatic features of neornithines are found in Mesozoic birds and are considered primitive for Aves. The phylogenetic levels at which most of the avian pneumatic features arose within Archosauria are uncertain. Until the phylogenetic levels at which homologous pneumatic features arose are determined, it is unwise to use most pneumatic characters in the discussion of avian origins. Within avian phylogeny, Ornithurae and Neornithes are well\u2013supported by pneumatic synapomorphies. There is a trend towards reduction of craniofacial pneumaticity within Hesperornithiformes. Within Neornithes, four derived pneumatic characters suggest that the Palaeognathae (ratites and tinamous) is monophyletic.", "keyphrases": ["mesozoic bird", "aves", "sinus", "quadrate"]}
{"id": "paleo.009903", "title": "Unusual Deep Water sponge assemblage in South China\u2014Witness of the end-Ordovician mass extinction", "abstract": "There are few sponges known from the end-Ordovician to early-Silurian strata all over the world, and no records of sponge fossils have been found yet in China during this interval. Here we report a unique sponge assemblage spanning the interval of the end-Ordovician mass extinction from the Kaochiapien Formation (Upper Ordovician-Lower Silurian) in South China. This assemblage contains a variety of well-preserved siliceous sponges, including both Burgess Shale-type and modern type taxa. It is clear that this assemblage developed in deep water, low energy ecosystem with less competitors and more vacant niches. Its explosion may be related to the euxinic and anoxic condition as well as the noticeable transgression during the end-Ordovician mass extinction. The excellent preservation of this assemblage is probably due to the rapid burial by mud turbidites. This unusual sponge assemblage provides a link between the Burgess Shale-type deep water sponges and the modern forms. It gives an excellent insight into the deep sea palaeoecology and the macroevolution of Phanerozoic sponges, and opens a new window to investigate the marine ecosystem before and after the end-Ordovician mass extinction. It also offers potential to search for exceptional fossil biota across the Ordovician-Silurian boundary interval in China.", "keyphrases": ["end-ordovician mass extinction", "kaochiapien formation", "ordovician-lower silurian", "south china"]}
{"id": "paleo.006877", "title": "A mechanism for freshening the Caribbean Sea in pre-Ice Age time", "abstract": "Many believe that the Central American Seaway closed near 4\u2009Ma and that that closure led to increased salinity in the Caribbean Sea and stronger Meridional Overturning Circulation in the Atlantic, which facilitated the waxing and waning of ice sheets in the Northern Hemisphere. We offer an alternative explanation for Caribbean salinification. The atmosphere transports approximately 0.23\u2009Sv (1\u2009Sv\u2009=\u2009106 m3s\u22121) of fresh water (moisture) from the Caribbean to the Pacific today, but that amount varies by >20% during El Nino\u2013Southern Oscillation events. Regressions of moisture transport against the Nino-3 index, a measure of the sea surface temperature in the eastern tropical Pacific, show less moisture transport from the Caribbean during El Nino events than average. Abundant evidence indicates that at 3\u20134\u2009Ma the eastern tropical Pacific was 3.5\u20134\u00b0C warmer than today, and if so, an extrapolation of such regressions suggests that smaller moisture transport across Central America might account for paleoceanographic inferences of a smaller salinity difference between the Caribbean and Pacific at that time. Accordingly, that decreased salinity difference at ~3\u20134\u2009Ma would not require blockage of relatively fresh Pacific water at ~2\u20134\u2009Ma by the closure of the Central American Seaway, but rather would be consistent with a transition from El Nino to La Nina-like conditions in the eastern tropical Pacific around that time.", "keyphrases": ["caribbean sea", "atmosphere", "moisture transport"]}
{"id": "10.1080/02724634.2003.10010947", "title": "Osteology of Tyrannosaurus Rex: Insights from a nearly complete Skeleton and High-Resolution Computed Tomographic Analysis of the Skull", "abstract": "ABSTRACT A detailed osteological description of Tyrannosaurus rex Osborn, 1905 is presented, based primarily on the most complete specimen yet collected of this taxon (FMNH PR2081, popularly known as \u201cSue\u201d) but also including observations from other specimens. Skull morphology of FMNH PR2081 is largely congruent with that described for previous specimens, but new details are added. Palatal morphology of FMNH PR2081 differs slightly from that of previously-described specimens\u2014the internal choanae are slightly larger relative to skull size, and the anterior expansion of the fused vomers is elongate. Posteriorly, the vomers pass medially for nearly the entire length of the pterygoids. High-resolution x-ray computed tomographic (CT) analysis of the skull reveals internal details not previously observed. Complex recess systems can be traced in the jugal, lacrymal, ectopterygoid, quadrate, exoccipital, supraoccipital, prootic, and basioccipital. The exoccipital recess was perforated by a small foramen on the posterodorsal surface of the paroccipital process, and may have communicated with pneumatic chambers in the atlas-axis complex. The maxillary antra were bound medially by a thin bony wall; traces of these walls in earlier CT studies of tyrannosaurid skulls may have led to the impression that these animals had bony maxillonasal turbintes. A digital endocast was constructed from these images, confirming many previous observations based on natural endocasts, but also yielding new details, such as the presence of a large and presumably pneumatic sinus in the prootic adjacent to the pathway for the maxillary-mandibular branches of the trigeminal nerve. The olfactory bulbs were very large. The postcranium is also largely congruent with previously published descriptions. The precaudal vertebral column was heavily pneumatized, with pneumatopores penetrating the centra and neural arches of all presacral vertebrae, the cervical ribs, and the anteriormost four sacral centra. Unusual structures are tentatively identified as a proatlas arch and a rib on the last presacral vertebrae, structures previously thought absent from tyrannosaurids. The \u201cmissing chevron\u201d partially responsible for claims that FMNH PR2081 is female was actually present. The gastralia are extensively fused anteriorly, and the morphology of the anteriormost gastral segments closely resembles the only published account of a tyrannosaurid sternum. This raises several possibilities, including the complete absence of a bony sternum in tyrannosaurids. The appendicular skeleton is congruent with those of other tyrannosaurids. A slender rodlike bone may represent a partial furcula, but this is not certain. The scapulocoracoids would probably not have met at the midline, but would nonetheless have closely approached each other in articulation. Several abnormalities in the skeleton have attracted popular attention. There is no defensible evidence for bite trauma on the skull, but the rib cage does show evidence for healed fractures. Lesions on the right scapulocoracoid and humerus coincide with fractured ribs on the right cervical-dorsal transition and may indicate a single trauma to the right side of the body. The left fibula is pathological, but may not have been fractured. Two fused tail vertebrae may preserve natural molds of the tail muscles.", "keyphrases": ["skull", "centra", "vertebrae"]}
{"id": "paleo.000793", "title": "Digestive and appendicular soft-parts, with behavioural implications, in a large Ordovician trilobite from the Fezouata Lagerst\u00e4tte, Morocco", "abstract": "Trilobites were one of the most successful groups of marine arthropods during the Palaeozoic era, yet their soft-part anatomy is only known from a few exceptionally-preserved specimens found in a handful of localities from the Cambrian to the Devonian. This is because, even if the sclerotized appendages were not destroyed during early taphonomic stages, they are often overprinted by the three-dimensional, mineralised exoskeleton. Inferences about the ventral anatomy and behavioural activities of trilobites can also be derived from the ichnological record, which suggests that most Cruziana and Rusophycus trace fossils were possibly produced by the actions of trilobites. Three specimens of the asaphid trilobite Megistaspis (Ekeraspis) hammondi, have been discovered in the Lower Ordovician Fezouata Konservat-Lagerst\u00e4tte of southern Morocco, preserving appendages and digestive tract. The digestive structures include a crop with digestive caeca, while the appendages display exopodal setae and slight heteropody (cephalic endopods larger and more spinose than thoracic and pygidial ones). The combination of these digestive structures and the heteropody has never been described together among trilobites, and the latter could assist in the understanding of the production of certain comb-like traces of the Cruziana rugosa group, which are extraordinarily abundant on the shallow marine shelves around Gondwana.", "keyphrases": ["trilobite", "morocco", "ekeraspis"]}
{"id": "10.1002/ajpa.10093", "title": "Late pleistocene human femoral diaphyseal curvature.", "abstract": "Anterior femoral curvature is a consistent characteristic of Pleistocene and recent humans, although variation exists in the degree of curvature among individuals and across populations. In particular, one group, the Neandertals, has been characterized for a century as having marked femoral curvature. To evaluate the degree of anterior femoral curvature in both Neandertals and other Late Pleistocene humans, their curvature subtenses and proximodistal positions were evaluated in the context of recent human variation. Recent human comparisons show little relationship between subtense (absolute curvature) and femoral length, suggesting that an index that incorporates subtense relative to the length of the femur is inappropriate for between-group assessments. Neandertals were statistically indistinguishable from Middle or earlier Upper Paleolithic modern humans in the degree of absolute curvature, all of whom had greater curvature on average than all later humans. Additionally, Neandertals and Qafzeh-Skhul early modern humans had a more distal point of maximum curvature than any other group. Curvature was not strongly correlated with functional considerations including body mass estimates, surrogate variables for body size, proximal femoral articular orientation, or knee anteroposterior dimensions. The functional role of femoral anterior curvature is unknown; however, the general decrease in curvature subtense closely parallels the between-group changes in inferred levels of mobility from femoral diaphyseal robusticity and shape, suggesting that femoral curvature may reflect mobility levels and patterns among Late Pleistocene and recent humans.", "keyphrases": ["femoral curvature", "recent human", "late pleistocene"]}
{"id": "10.3389/fevo.2019.00166", "title": "Evolution of Early Equus in Italy, Georgia, the Indian Subcontinent, East Africa, and the Origins of African Zebras", "abstract": "We report here ecological and morphological characterization of the main Old World Equus in North America, Asia, Europe and Africa, by comparing the studied fossil forms with the living Equus grevyi zebra. Equus simplicidens from North America, Equus livenzovenzis, Equus stenonis and Equus stehlini from Italy, Equus sivalensis from India, Equus cf. stenonis and a small Equus from Georgia (Caucasus), Equus oldowayensis, Equus koobiforensis and Equus cf. tabeti from Kenya and the extant Equus grevyi are described in their cranial and dental features and are compared in morphological postcranial dimensions by means of log10 ratio analysis. The occurrence of the two horses at the Dmanisi Homo site in Georgia is reported here for the first time. Our comparative analyses allow to confirm the primitive lineage of the ancient zebras as derivate from Equus simplicidens, and the successive evolution of the stenonine horses in Asia, South Asia, and Europe during the Plio \u2013 Pleistocene. The morphological analysis has reveal a clear trend in third metacarpals and third metatarsals of E. simpicidens, the small Equus from Dmanisi and E. grevyi, suggesting a close relationship between these species. The trend of the stenonine Equus from Europe and Asia confirms the possible evolution from the North America Equus simplicidens. The description of all the Old World Equus is integrated with an overview of their paleoecological context, with a referred section for each locality where these fossils were found. This contribution represents a comprehensive review of the present knowledge of the Old World Equus evolutionary history, with some new important data in deciphering the deep origin and evolution of ancient and living zebras.", "keyphrases": ["italy", "georgia", "equus stenonis", "metatarsal"]}
{"id": "10.1073/pnas.1601077113", "title": "Bison phylogeography constrains dispersal and viability of the Ice Free Corridor in western Canada", "abstract": "The Ice Free Corridor has been invoked as a route for Pleistocene human and animal dispersals between eastern Beringia and more southerly areas of North America. Despite the significance of the corridor, there are limited data for when and how this corridor was used. Hypothetical uses of the corridor include: the first expansion of humans from Beringia into the Americas, northward postglacial expansions of fluted point technologies into Beringia, and continued use of the corridor as a contact route between the north and south. Here, we use radiocarbon dates and ancient mitochondrial DNA from late Pleistocene bison fossils to determine the chronology for when the corridor was open and viable for biotic dispersals. The corridor was closed after \u223c23,000 until 13,400 calendar years ago (cal y BP), after which we find the first evidence, to our knowledge, that bison used this route to disperse from the south, and by 13,000 y from the north. Our chronology supports a habitable and traversable corridor by at least 13,000 cal y BP, just before the first appearance of Clovis technology in interior North America, and indicates that the corridor would not have been available for significantly earlier southward human dispersal. Following the opening of the corridor, multiple dispersals of human groups between Beringia and interior North America may have continued throughout the latest Pleistocene and early Holocene. Our results highlight the utility of phylogeographic analyses to test hypotheses about paleoecological history and the viability of dispersal routes over time.", "keyphrases": ["dispersal", "ice free corridor", "north america", "bison"]}
{"id": "paleo.004826", "title": "Facies, magnetic susceptibility and timing of the Late Devonian Frasnian/Famennian boundary interval (Xom Nha Formation, Central Vietnam)", "abstract": "Upper Devonian carbonates deposited through the Frasnian/Famennian (F/F) stage boundary in the Xom Nha Formation, Central Vietnam, were studied. The section is mainly composed of fossiliferous, brecciated, and laminated limestone beds, while shale beds occur in a subordinate number. Microfacies generally suggests a hemipelagic setting on an outer shelf environment with low sedimentation rates. A sediment accumulation rate of 0.217 cm/kyrs for this section is calculated. The Xom Nha section does not exhibit characteristic black shales or black limestones through the F/F boundary, but instead shows a similar lithology in comparison to other F/F sections in Southeast Asia. The carbonates yielded abundant conodonts, which represent mainly cosmopolitan species but the section differs from most sections in Europe in showing relatively high numbers of Palmatolepis linguiformis species. Deposition through the F/F boundary interval reported here for the Xom Nha section appears to have occurred during a ~1.2 Ma, and shows well-defined climate cyclicity.", "keyphrases": ["boundary interval", "xom nha formation", "central vietnam", "carbonate sample", "preparation method"]}
{"id": "10.1206/3773.2", "title": "Reassessment of Chadrolagus and Litolagus (Mammalia: Lagomorpha) and a New Genus of North American Eocene Lagomorph from Wyoming", "abstract": "ABSTRACT Lagomorphs from the late Eocene and Eocene-Oligocene transition of North America, apart from the abundant and fairly speciose Palaeolagus, are represented by some rare and enigmatic genera, including monospecific Chadrolagus and Litolagus, of uncertain infraordinal relationship. In this paper new specimens of lagomorphs from the Chadronian and Orellan of Montana and Wyoming are presented. They include Chadrolagus emryi from the early Chadronian of the Renova Formation, Beaverhead Basin (Montana), and the late Chadronian of the Dunbar Creek and Cook Ranch Formations (Montana), extending the stratigraphic range of this species to the entire Chadronian interval. Further, previously unreported material, originally collected by M.F. Skinner during his fieldwork in Wyoming (near the Chadronian-Orellan boundary in age), is described and figured. This includes an exquisitely preserved skull of Litolagus molidens, and Limitolagus roosevelti, gen. et sp. nov., represented by mandibular and dental material from the Chadronian-Orellan boundary. L. roosevelti shares many similarities in dental structure with Chadrolagus, but its size is close to Litolagus molidens. The information provided by newly described material and a revision of the type specimens and topotypic series of Chadrolagus emryi and Litolagus molidens allow for an extended diagnosis of these taxa and a preliminary phylogenetic analysis of Paleogene North American lagomorphs with Desmatolagus gobiensis as an outgroup. The skull of Litolagus molidens shows many derived characters: shortening of the palatal bridge and the reduction of its palatine portion, greater skull height, and an increase in the size of the auditory bullae. The greater basicranial angle and relatively wider choanae indicate increased cursorial adaptations. A cladistic analysis shows that there is no immediate ancestral relationship between Chadrolagus and Litolagus, and it supports an advanced phylogenetic position for Litolagus closer to Archaeolaginae, suggested by the cranial and dental morphology. Limitolagus is related closely to Chadrolagus and paraphyly of Palaeolagus is strongly suggested, due to a placement of P. burkei between Limitolagus and the clade composed of Archaeolagus + Litolagus.", "keyphrases": ["chadrolagus", "skull", "north american lagomorph"]}
{"id": "10.1144/jgs2018-195", "title": "The Spence Shale Lagerst\u00e4tte: an important window into Cambrian biodiversity", "abstract": "The Spence Shale Member of the Langston Formation is a Cambrian (Miaolingian: Wuliuan) Lagerst\u00e4tte in northeastern Utah and southeastern Idaho. It is older than the more well-known Wheeler and Marjum Lagerst\u00e4tten from western Utah, and the Burgess Shale from Canada. The Spence Shale shares several species with these younger deposits, yet it also contains a remarkable number of unique species. Because of its relatively broad geographical distribution, and the variety of palaeoenvironments and taphonomy, the fossil composition and likelihood of recovering weakly skeletonized (or soft-bodied) taxa varies across localities. The Spence Shale is widely acknowledged not only for its soft-bodied taxa, but also for its abundant trilobites and hyoliths. Recent discoveries from the Spence Shale include problematic taxa and provide insights about the nature of palaeoenvironmental and taphonomic variation between different localities. Supplementary material: A generic presence\u2013absence matrix of the Spence Shale fauna and a list of the Spence Shale localities are available at: https://doi.org/10.6084/m9.figshare.c.4423145", "keyphrases": ["spence shale", "biodiversity", "idaho", "soft-bodied fossil", "tissue"]}
{"id": "paleo.010516", "title": "Detecting archaic introgression using an unadmixed outgroup", "abstract": "Human populations outside of Africa have experienced at least two bouts of introgression from archaic humans, from Neanderthals and Denisovans. In Papuans there is prior evidence of both these introgressions. Here we present a new approach to detect segments of individual genomes of archaic origin without using an archaic reference genome. The approach is based on a hidden Markov model that identifies genomic regions with a high density of single nucleotide variants (SNVs) not seen in unadmixed populations. We show using simulations that this provides a powerful approach to identifying segments of archaic introgression with a low rate of false detection, given data from a suitable outgroup population is available, without the archaic introgression but containing a majority of the variation that arose since initial separation from the archaic lineage. Furthermore our approach is able to infer admixture proportions and the times both of admixture and of initial divergence between the human and archaic populations. We apply the model to detect archaic introgression in 89 Papuans and show how the identified segments can be assigned to likely Neanderthal or Denisovan origin. We report more Denisovan admixture than previous studies and find a shift in size distribution of fragments of Neanderthal and Denisovan origin that is compatible with a difference in admixture time. Furthermore, we identify small amounts of Denisova ancestry in South East Asians and South Asians.", "keyphrases": ["introgression", "hidden markov model", "genomic region"]}
{"id": "paleo.012169", "title": "Phylogenetic Analysis of Pelecaniformes (Aves) Based on Osteological Data: Implications for Waterbird Phylogeny and Fossil Calibration Studies", "abstract": "Background Debate regarding the monophyly and relationships of the avian order Pelecaniformes represents a classic example of discord between morphological and molecular estimates of phylogeny. This lack of consensus hampers interpretation of the group's fossil record, which has major implications for understanding patterns of character evolution (e.g., the evolution of wing-propelled diving) and temporal diversification (e.g., the origins of modern families). Relationships of the Pelecaniformes were inferred through parsimony analyses of an osteological dataset encompassing 59 taxa and 464 characters. The relationships of the Plotopteridae, an extinct family of wing-propelled divers, and several other fossil pelecaniforms (Limnofregata, Prophaethon, Lithoptila, ?Borvocarbo stoeffelensis) were also assessed. The antiquity of these taxa and their purported status as stem members of extant families makes them valuable for studies of higher-level avian diversification. Methodology/Principal Findings Pelecaniform monophyly is not recovered, with Phaethontidae recovered as distantly related to all other pelecaniforms, which are supported as a monophyletic Steganopodes. Some anatomical partitions of the dataset possess different phylogenetic signals, and partitioned analyses reveal that these discrepancies are localized outside of Steganopodes, and primarily due to a few labile taxa. The Plotopteridae are recovered as the sister taxon to Phalacrocoracoidea, and the relationships of other fossil pelecaniforms representing key calibration points are well supported, including Limnofregata (sister taxon to Fregatidae), Prophaethon and Lithoptila (successive sister taxa to Phaethontidae), and ?Borvocarbo stoeffelensis (sister taxon to Phalacrocoracidae). These relationships are invariant when \u2018backbone\u2019 constraints based on recent avian phylogenies are imposed. Conclusions/Significance Relationships of extant pelecaniforms inferred from morphology are more congruent with molecular phylogenies than previously assumed, though notable conflicts remain. The phylogenetic position of the Plotopteridae implies that wing-propelled diving evolved independently in plotopterids and penguins, representing a remarkable case of convergent evolution. Despite robust support for the placement of fossil taxa representing key calibration points, the successive outgroup relationships of several \u201cstem fossil + crown family\u201d clades are variable and poorly supported across recent studies of avian phylogeny. Thus, the impact these fossils have on inferred patterns of temporal diversification depends heavily on the resolution of deep nodes in avian phylogeny.", "keyphrases": ["pelecaniformes", "consensus", "temporal diversification", "extinct family", "plotopterid"]}
{"id": "paleo.010522", "title": "Direct Comparisons of 2D and 3D Dental Microwear Proxies in Extant Herbivorous and Carnivorous Mammals", "abstract": "The analysis of dental microwear is commonly used by paleontologists and anthropologists to clarify the diets of extinct species, including herbivorous and carnivorous mammals. Currently, there are numerous methods employed to quantify dental microwear, varying in the types of microscopes used, magnifications, and the characterization of wear in both two dimensions and three dimensions. Results from dental microwear studies utilizing different methods are not directly comparable and human quantification of wear features (e.g., pits and scratches) introduces interobserver error, with higher error being produced by less experienced individuals. Dental microwear texture analysis (DMTA), which analyzes microwear features in three dimensions, alleviates some of the problems surrounding two-dimensional microwear methods by reducing observer bias. Here, we assess the accuracy and comparability within and between 2D and 3D dental microwear analyses in herbivorous and carnivorous mammals at the same magnification. Specifically, we compare observer-generated 2D microwear data from photosimulations of the identical scanned areas of DMTA in extant African bovids and carnivorans using a scanning white light confocal microscope at 100x magnification. Using this magnification, dental microwear features quantified in 2D were able to separate grazing and frugivorous bovids using scratch frequency; however, DMTA variables were better able to discriminate between disparate dietary niches in both carnivorous and herbivorous mammals. Further, results demonstrate significant interobserver differences in 2D microwear data, with the microwear index remaining the least variable between experienced observers, consistent with prior research. Overall, our results highlight the importance of reducing observer error and analyzing dental microwear in three dimensions in order to consistently interpret diets accurately.", "keyphrases": ["carnivorous mammal", "error", "dmta"]}
{"id": "paleo.000973", "title": "The early elasmobranch Phoebodus: phylogenetic relationships, ecomorphology and a new time-scale for shark evolution", "abstract": "Anatomical knowledge of early chondrichthyans and estimates of their phylogeny are improving, but many taxa are still known only from microremains. The nearly cosmopolitan and regionally abundant Devonian genus Phoebodus has long been known solely from isolated teeth and fin spines. Here, we report the first skeletal remains of Phoebodus from the Famennian (Late Devonian) of the Ma\u00efder region of Morocco, revealing an anguilliform body, specialized braincase, hyoid arch, elongate jaws and rostrum, complementing its characteristic dentition and ctenacanth fin spines preceding both dorsal fins. Several of these features corroborate a likely close relationship with the Carboniferous species Thrinacodus gracia, and phylogenetic analysis places both taxa securely as members of the elasmobranch stem lineage. Identified as such, phoebodont teeth provide a plausible marker for range extension of the elasmobranchs into the Middle Devonian, thus providing a new minimum date for the origin of the chondrichthyan crown-group. Among pre-Carboniferous jawed vertebrates, the anguilliform body shape of Phoebodus is unprecedented, and its specialized anatomy is, in several respects, most easily compared with the modern frilled shark Chlamydoselachus. These results add greatly to the morphological, and by implication ecological, disparity of the earliest elasmobranchs.", "keyphrases": ["chondrichthyan", "vertebrate", "eastern anti-atlas", "tooth"]}
{"id": "10.1080/14772019.2010.526639", "title": "A revision of enantiornithine (Aves: Ornithothoraces) skull morphology", "abstract": "Enantiornithines are the most speciose avian clade in the Mesozoic, with a fossil record that nearly spans the Cretaceous; however, with less than half of known taxa preserving skull material, our understanding of their cranial morphology remains incomplete. Here we present a comprehensive overview of the current knowledge of enantiornithine skull anatomy and discuss the range of morphologies known for each of the main cranial elements. The typical enantiornithine skull retains numerous ancestral features such as the absence of fusion among bones, the presence of a postorbital bone, a primitive quadrate with a single headed otic process, an unforked dentary, and teeth. The postorbital in at least one taxon is unreduced, suggesting the existence of a complete infratemporal fenestra and thus an unmodified diapsid skull as in confuciusornithids. The rostrum is well known and shows considerable variation, typical of theropods; however, in terms of rostral proportions, enantiornithines are extremely limited within the modern avian spectrum. Although Late Cretaceous skull material is extremely fragmentary, when compared to Early Cretaceous material it reveals a trend towards more specialized morphologies in younger taxa. The foramen magnum in all taxa points caudally, indicating that the \u2018flexed\u2019 type skull morphology may not have evolved in this group. Enantiornithine teeth show considerable diversity in numbers, size, morphology and placement, ranging from taxa with large teeth found throughout the jaws to taxa with small, rostrally restricted teeth, to the fully edentulous. Despite limited preservation of skull material, a number of trophic specializations can be deduced from the range of preserved morphologies, further hinting at the morphological and ecological diversity of the Cretaceous Enantiornithes.", "keyphrases": ["enantiornithine", "morphology", "tooth"]}
{"id": "paleo.010328", "title": "No Evidence of Neandertal mtDNA Contribution to Early Modern Humans", "abstract": "The retrieval of mitochondrial DNA (mtDNA) sequences from four Neandertal fossils from Germany, Russia, and Croatia has demonstrated that these individuals carried closely related mtDNAs that are not found among current humans. However, these results do not definitively resolve the question of a possible Neandertal contribution to the gene pool of modern humans since such a contribution might have been erased by genetic drift or by the continuous influx of modern human DNA into the Neandertal gene pool. A further concern is that if some Neandertals carried mtDNA sequences similar to contemporaneous humans, such sequences may be erroneously regarded as modern contaminations when retrieved from fossils. Here we address these issues by the analysis of 24 Neandertal and 40 early modern human remains. The biomolecular preservation of four Neandertals and of five early modern humans was good enough to suggest the preservation of DNA. All four Neandertals yielded mtDNA sequences similar to those previously determined from Neandertal individuals, whereas none of the five early modern humans contained such mtDNA sequences. In combination with current mtDNA data, this excludes any large genetic contribution by Neandertals to early modern humans, but does not rule out the possibility of a smaller contribution.", "keyphrases": ["modern human", "croatia", "human dna", "contamination"]}
{"id": "10.1002/2017pa003201", "title": "BAYSPLINE: A New Calibration for the Alkenone Paleothermometer", "abstract": "The alkenone\u2010based U 37K\u2032 proxy is a cornerstone of paleoclimatology, providing insight into the temperature history of the Earth's surface ocean. Although the relationship between U 37K\u2032 and sea surface temperatures (SSTs) is robust and well supported by experimental data, there remain outstanding issues regarding the seasonality of production of alkenones and the response of U 37K\u2032 at very warm and cold SSTs. Using a data set of over 1,300 core\u2010top U 37K\u2032 measurements, we find compelling evidence of seasonal production in the North Atlantic, North Pacific, and Mediterranean Oceans. We also find significant attenuation of the U 37K\u2032 response to SST at warm temperatures (>24\u00b0C), with the slope reduced by nearly 50% as U 37K\u2032 approaches unity. To account for these observations in a calibration, we develop a new Bayesian B\u2010spline regression model, BAYSPLINE, for the U 37K\u2032 paleothermometer. BAYSPLINE produces similar estimates as previous calibrations below \u223c24\u00b0, but above this point it predicts larger SST changes, in accordance with the attenuation of the U 37K\u2032 response. Example applications of BAYSPLINE demonstrate that its treatment of seasonality and slope attenuation improves paleoclimatic interpretations, with important consequences for the inference of SSTs in the tropical oceans. BAYSPLINE facilitates a probabilistic approach to paleoclimate, building upon growing efforts to develop more formalized statistical frameworks for paleoceanographic reconstruction.", "keyphrases": ["sst", "attenuation", "bayspline"]}
{"id": "paleo.002957", "title": "The Oldest Brachiopods from the Lower Cambrian of South Australia", "abstract": "The morphology and organophosphatic shell structure of the paterinate brachiopod Askepasma is documented using new and previously collected specimens from the lower Cambrian of South Australia. Lack of adequately preserved material has seen the majority of paterinate specimens previously reported from South Australia referred to the genus Askepasma and treated under open nomenclature. Large collections of paterinates from the lower Cambrian Wilkawillina, Ajax, and Wirrapowie limestones in the Arrowie Basin, South Australia have prompted redescription of the type species Askepasma toddense and the erection of a new species, Askepasma saproconcha sp. nov. Askepasma saproconcha sp. nov. currently represents the oldest known brachiopod from the lower Cambrian successions in South Australia with a FAD in pre-trilobitic (Terreneuvian, Cambrian Stage 2, lower Atdabanian) strata in the basal part of the Wilkawillina and Wirrapowie limestones. Askepasma toddense predominantly occurs in Abadiella huoi Zone equivalent strata (Unnamed Cambrian Series 2, Stage 3, middle-upper Atdabanian) in the upper part of the lower Wilkawillina, Wirrapowie, and Ajax limestones. The shell microstructure of Askepasma suggests a proximal stem group position within the Brachiopoda and similarities with tommotiid taxa provides further evidence that the ancestry of crown group brachiopods is firmly entrenched within the Tommotiida.", "keyphrases": ["brachiopod", "south australia", "shell structure"]}
{"id": "paleo.011147", "title": "Proteome degradation in fossils: investigating the longevity of protein survival in ancient bone", "abstract": "RATIONALE We report the use of proteomics techniques to study how the fossil bone proteome changes in complexity over one million years. METHODS We include the attempted use of a previously unreported methodology in proteome research, to remove the dominant bone collagens using bacterial collagenase as well as conventional shotgun proteomics methodology following digestion with the protease trypsin. In this study we expand upon a set of 19 bovine sub-fossil specimens ranging over one and a half million years that had previously been shown to possess collagen, using a total of 46 LTQ-Orbitrap liquid chromatography/tandem mass spectrometry (LC/MS/MS) analyses containing 462,186 precursor ion analyses. RESULTS Although many types of proteins can typically be identified in recent bone, in degraded bone we observe a rapid loss of lower abundance proteins. Abundant serum proteins such as serum albumin and alpha-2-HS-glycoprotein appear to be more easily recovered in ancient bone, both being identified in specimens dating to the Early Pleistocene, the earliest period tested in this study. Proteins belonging to the leucine-rich repeat family such as lumican, biglycan and chondroadherin also survive well, possibly because of their interactions with bone collagen. CONCLUSIONS Of these 'survivor proteins' A2HSG shows a remarkable amount of sequence variation, making it potentially one of the most useful proteins to study for species identification and phylogenetic inference in archaeological and palaeontological bone.", "keyphrases": ["protein", "ancient bone", "sub-fossil specimen", "tandem mass spectrometry", "buckley"]}
{"id": "10.1017/S0094837300006709", "title": "The relationship of the scleractinian corals to the rugose corals", "abstract": "The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are: (1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa. (2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors. (3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.", "keyphrases": ["coral", "scleractinia", "rugosa"]}
{"id": "paleo.000806", "title": "Dinosaur biodiversity declined well before the asteroid impact, influenced by ecological and environmental pressures", "abstract": "The question why non-avian dinosaurs went extinct 66 million years ago (Ma) remains unresolved because of the coarseness of the fossil record. A sudden extinction caused by an asteroid is the most accepted hypothesis but it is debated whether dinosaurs were in decline or not before the impact. We analyse the speciation-extinction dynamics for six key dinosaur families, and find a decline across dinosaurs, where diversification shifted to a declining-diversity pattern ~76 Ma. We investigate the influence of ecological and physical factors, and find that the decline of dinosaurs was likely driven by global climate cooling and herbivorous diversity drop. The latter is likely due to hadrosaurs outcompeting other herbivores. We also estimate that extinction risk is related to species age during the decline, suggesting a lack of evolutionary novelty or adaptation to changing environments. These results support an environmentally driven decline of non-avian dinosaurs well before the asteroid impact.", "keyphrases": ["decline", "asteroid impact", "other herbivore"]}
{"id": "10.1029/2008JB005644", "title": "Determination of rapid Deccan eruptions across the Cretaceous-Tertiary boundary using paleomagnetic secular variation: 2. Constraints from analysis of eight new sections and synthesis for a 3500-m-thick composite section", "abstract": "[1]\u00a0The present paper completes a restudy of the main lava pile in the Deccan flood basalt province (trap) of India. Chenet et al. (2008) reported results from the upper third, and this paper reports the lower two thirds of the 3500-m-thick composite section. The methods employed are the same, i.e., combined use of petrology, volcanology, chemostratigraphy, morphology, K-Ar absolute dating, study of sedimentary alteration horizons, and as the main correlation tool, analysis of detailed paleomagnetic remanence directions. The thickness and volume of the flood basalt province studied in this way are therefore tripled. A total of 169 sites from eight new sections are reported in this paper. Together with the results of Chenet et al. (2008), these data represent in total 70% of the 3500-m combined section of the main Deccan traps province. This lava pile was erupted in some 30 major eruptive periods or single eruptive events (SEE), each with volumes ranging from 1000 to 20,000 km3 and 41 individual lava units with a typical volume of 1300 km3. Paleomagnetic analysis shows that some SEEs with thicknesses attaining 200 m were emplaced over distances in excess of 100 km (both likely underestimates, due to outcrop conditions) and up to 800 km. The total time of emission of all combined SEEs could have been (much) less than 10 ka, with most of the time recorded in a very small number of intervening alteration levels marking periods of volcanic quiescence (so-called \u201cbig red boles\u201d). The number of boles, thickness of the pulses, and morphology of the traps suggest that eruptive fluxes and volumes were larger in the older formations and slowed down with more and longer quiescence periods in the end. On the basis of geochronologic results published by Chenet et al. (2007) and paleontological results from Keller et al. (2008), we propose that volcanism occurred in three rather short, discrete phases or megapulses, an early one at \u223c67.5 \u00b1 1 Ma near the C30r/C30n transition and the two largest around 65 \u00b1 1 Ma, one entirely within C29r just before the K-T boundary, the other shortly afterward spanning the C29r/C29n reversal. We next estimate sulfur dioxide (likely a major agent of environmental stress) amounts and fluxes released by SEEs: they would have ranged from 5 to 100 Gt and 0.1 to 1 Gt/a, respectively, over durations possibly as short as 100 years for each SEE. The chemical input of the Chicxulub impact would have been on the same order as that of a very large single pulse. The impact, therefore, appears as important but incremental, neither the sole nor main cause of the Cretaceous-Tertiary mass extinctions.", "keyphrases": ["composite section", "volcanism", "mass extinction"]}
{"id": "10.1111/acv.12605", "title": "European bison conservation cannot afford to ignore alternative hypotheses: a commentary on Perzanowski et al. (2019)", "abstract": "Conservation science is about developing a robust understanding of how to reduce threats and extinction risks for biodiversity, as expressed in the International Union for the Conservation of Nature (IUCN) Conservation Action Plan approach (IUCN/SSC, 2013). As a branch of science, it must therefore follow the scientific best practice of considering alternative hypotheses in order to minimise the risk of erroneously increasing threats or extinction risks for species (Caughley, 1994). The consequences of failure to consider alternative hypotheses are not trivial. Conservation interventions that are developed from artificially constrained and limited perspectives of a species\u2019 ecological requirements likely increase the risk of population and species losses, the latter being irreversible. We are concerned that Perzanowski et al. (2019), in modelling an approach for conserving the European bison Bison bonasus in Poland, ignored an alternative hypothesis that identifies the European bison as a refugee species due to its current confinement in forest habitat (Kerley, Kowalczyk & Cromsigt, 2012). Perzanowski et al. (2019) choose to frame their modelling approach within the paradigm that the European bison is a forest specialist, with occurrence data that reflect the prevailing confinement of the species to forest habitats, where it is managed through supplementary feeding and culling to mitigate movements and range expansion to open habitats (Kerley et al., 2012). The Refugee Species Hypothesis (RSH) for the European bison was developed in 2012, and reflects the evolutionary background, palaeoecology, life history, feeding morphology, diet choice, and habitat selection of the European bison (Kerley et al., 2012). All of these point to the European bison being adapted to more open, grass-rich habitats. Furthermore, Kerley et al. (2012) demonstrate that the current confinement of European bison to forests reflects the trapping of this species in forest habitat by human pressures and management, a process that has been ongoing for hundreds of years (Samojlik et al., 2019). The RSH predicts that confining the European bison to forest habitat has an array of fitness and management consequences. These predictions include reduced access to preferred/optimal resources (see habitat preferences below) and decreased fitness, as well as the costs of supplementary feeding that forest-confined bison require, increased vulnerability to disease and parasites, and human\u2013wildlife conflicts when bison attempt to move out of forests (Hofman-Kami nska & Kowalczyk, 2012; Kerley et al., 2012; Kowalczyk et al., 2013; Ko\u0142odziej-Soboci nska et al., 2016). This problem is exacerbated in coniferous forests where bison density is lower than in mixed forests (Table 1), and levels of human\u2013 bison conflict are elevated (Hofman-Kami nska & Kowalczyk, 2012). Perzanowski et al. (2019) emphasize that \u2018The majority of forested area is coniferous\u2019, which suggests that applying their model will lead to low bison densities and heightened human\u2013wildlife conflict. Additionally, the forest specialist paradigm will unduly restrict the global European", "keyphrases": ["alternative hypothesis", "forest specialist", "european bison"]}
{"id": "paleo.007732", "title": "A cryptic record of Burgess Shale\u2010type diversity from the early Cambrian of Baltica", "abstract": "Exceptionally preserved \u2018Burgess Shale\u2010type\u2019 fossil assemblages from the Cambrian of Laurentia, South China and Australia record a diverse array of non\u2010biomineralizing organisms. During this time, the palaeocontinent Baltica was geographically isolated from these regions, and is conspicuously lacking in terms of comparable accessible early Cambrian Lagerst\u00e4tten. Here we report a diverse assemblage of small carbonaceous fossils (SCFs) from the early Cambrian (Stage 4) File Haidar Formation of southeast Sweden and surrounding areas of the Baltoscandian Basin, including exceptionally preserved remains of Burgess Shale\u2010type metazoans and other organisms. Recovered SCFs include taxonomically resolvable ecdysozoan elements (priapulid and palaeoscolecid worms), lophotrochozoan elements (annelid chaetae and wiwaxiid sclerites), as well as \u2018protoconodonts\u2019, denticulate feeding structures, and a background of filamentous and spheroidal microbes. The annelids, wiwaxiids and priapulids are the first recorded from the Cambrian of Baltica. The File Haidar SCF assemblage is broadly comparable to those recovered from Cambrian basins in Laurentia and South China, though differences at lower taxonomic levels point to possible environmental or palaeogeographical controls on taxon ranges. These data reveal a fundamentally expanded picture of early Cambrian diversity on Baltica, and provide key insights into high\u2010latitude Cambrian faunas and patterns of SCF preservation. We establish three new taxa based on large populations of distinctive SCFs: Baltiscalida njorda gen. et sp. nov. (a priapulid), Baltichaeta jormunganda gen. et sp. nov. (an annelid) and Baltinema rana gen. et sp. nov. (a filamentous problematicum).", "keyphrases": ["baltica", "file haidar formation", "cambrian fossil priapulid", "terreneuvian", "isolated scalid"]}
{"id": "10.3389/fgene.2019.01241", "title": "Evolutionary Models for the Diversification of Placental Mammals Across the KPg Boundary", "abstract": "Deciphering the timing of the placental mammal radiation is a longstanding problem in evolutionary biology, but consensus on the tempo and mode of placental diversification remains elusive. Nevertheless, an accurate timetree is essential for understanding the role of important events in Earth history (e.g., Cretaceous Terrestrial Revolution, KPg mass extinction) in promoting the taxonomic and ecomorphological diversification of Placentalia. Archibald and Deutschman described three competing models for the diversification of placental mammals, which are the Explosive, Long Fuse, and Short Fuse Models. More recently, the Soft Explosive Model and Trans-KPg Model have emerged as additional hypotheses for the placental radiation. Here, we review molecular and paleontological evidence for each of these five models including the identification of general problems that can negatively impact divergence time estimates. The Long Fuse Model has received more support from relaxed clock studies than any of the other models, but this model is not supported by morphological cladistic studies that position Cretaceous eutherians outside of crown Placentalia. At the same time, morphological cladistics has a poor track record of reconstructing higher-level relationships among the orders of placental mammals including the results of new pseudoextinction analyses that we performed on the largest available morphological data set for mammals (4,541 characters). We also examine the strengths and weaknesses of different timetree methods (node dating, tip dating, and fossilized birth-death dating) that may now be applied to estimate the timing of the placental radiation. While new methods such as tip dating are promising, they also have problems that must be addressed if these methods are to effectively discriminate among competing hypotheses for placental diversification. Finally, we discuss the complexities of timetree estimation when the signal of speciation times is impacted by incomplete lineage sorting (ILS) and hybridization. Not accounting for ILS results in dates that are older than speciation events. Hybridization, in turn, can result in dates than are younger or older than speciation dates. Disregarding this potential variation in \"gene\" history across the genome can distort phylogenetic branch lengths and divergence estimates when multiple unlinked genomic loci are combined together in a timetree analysis.", "keyphrases": ["diversification", "placental mammal", "eutherian", "same time"]}
{"id": "paleo.000125", "title": "The dentition of a well-preserved specimen of Camarasaurus sp.: implications for function, tooth replacement, soft part reconstruction, and food intake", "abstract": "The basal macronarian genus Camarasaurus was the most common sauropod in the Upper Jurassic Morrison Formation of North America and is known from several complete and partial skeletons. The specimen used for this study is Camarasaurus sp. SMA 0002 from the Sauriermuseum Aathal, Switzerland. This specimen was found in the Howe-Stephens Quarry, Bighorn Basin, WY, USA. In this study, the dental morphology, characterized by the spatulate, broad-crowned teeth, the tooth replacement pattern, and the function of the dentition and its implications for food intake is described. Features such as the absence of denticles, the wrinkled pattern of the enamel, and the occurrence of large wear facets on older teeth are characteristic for Camarasaurus sp. A slab of sediment with soft tissue impressions ranging up to the middle part of the crown suggests the presence of a gingival soft tissue structure partially covering the teeth. The wrinkled enamel on the crown of the teeth of Camarasaurus sp. and other sauropods is interpreted as indication of this cover of gingival connective tissue. In addition, there possibly was a keratinous beak, which together with the gingiva held the teeth in the jaw and provided stability for teeth in which the root is almost completely resorbed.", "keyphrases": ["dentition", "tooth", "sauropod", "wear facet", "gingival connective tissue"]}
{"id": "10.2475/ajs.305.2.147", "title": "Implications of the evolution of organic acid moieties for basalt weathering over geological time", "abstract": "Concentrations of organic acids in prebiotic soils were presumably low, given limitations in abiotic synthesis and the limited lifetimes of organic molecules before the ultraviolet shield developed on early Earth. Prokaryotes, the first land- colonizing organisms, commonly secrete aliphatic carboxylic acids, and, less exten- sively, secrete aromatic compounds as siderophores and antibiotics. In contrast, secretion of aromatic acids is considerable for fungi, lichens, and vascular plants. Aromatic acids are also produced by degradation of high-molecular-weight compounds from lignin and tannin, both abundant in vascular plants. The proportion of aromatic carboxylic acids in soil solutions therefore probably increased with the evolution of higher order organisms. As biomass of organisms increased over geological time, concentrations of organic acids in soil solutions and, in turn, the extent of ligand- promoted dissolution of minerals probably increased. To elucidate the contribution of ligands during weathering on early Earth, Columbia River basalt was dissolved under oxic and anoxic conditions in the presence (0.001 or 0.01 M) and absence of several organic ligands in batch experiments at pH 6. Release of all elements including Si was enhanced considerably in the presence of organic ligands. Citrate (tridentate) and gallate (tetradentate) increased element release to the greatest extent among the aliphatic and aromatic ligands, respectively. The extent of element mobilization observed for the aliphatic ligands decreased in the order: citrate > oxalate malonate, and for the aromatic ligands: gallate > salicy- late phthalate. The effects of the ligands generally followed trends in cation-ligand stability constants, but aromatic ligands were less effective in element mobilization than aliphatic ligands. One exception was gallate, an aromatic ligand, which signifi- cantly enhanced Cu release. Ligand-promoted mobilization of Cu may therefore have increased over geological time with the increase in the proportion of aromatic ligands. In the presence of organic ligands, Fe was mobilized from basalt considerably more than Al even under oxic conditions. Complexation of Fe with organic ligands may have mobilized Fe in Precambrian paleosols where little Al mobility is observed. Extent of P and Y release was minor in ligand-free experiments and considerable with ligands regardless of PO2 . Release of Cu was considerable under oxic conditions, especially with ligands, and minor under anoxic conditions. Mobility patterns of P and Y could thus possibly serve as \"organomarkers\" (indicative of prevalence of organic ligands in soil solutions) and mobility patterns of Cu could possibly serve as \"oxymarkers\" (indicative of the presence of molecular oxygen), respectively, in ancient soils.", "keyphrases": ["basalt", "geological time", "oxic condition"]}
{"id": "paleo.009295", "title": "Insights into a 429-million-year-old compound eye", "abstract": "In all arthropods the plesiomorphic (ancestral character state) kind of visual system commonly is considered to be the compound eye. Here we are able to show the excellently preserved internal structures of the compound eye of a 429 Mya old Silurian trilobite, Aulacopleura koninckii (Barrande, 1846). It shows the characteristic elements of a modern apposition eye, consisting of 8 (visible) receptor cells, a rhabdom, a thick lens, screening pigment (cells), and in contrast to a modern type, putatively just a very thin crystalline cone. Functionally the latter underlines the idea of a primarily calcitic character of the lens because of its high refractive properties. Perhaps the trilobite was translucent. We show that this Palaeozoic trilobite in principle was equipped with a fully modern type of visual system, a compound eye comparable to that of living bees, dragonflies and many diurnal crustaceans. It is an example of excellent preservation, and we hope that this manuscript will be a starting point for more research work on fossil evidence, and to develop a deeper understanding of the evolution of vision.", "keyphrases": ["compound eye", "trilobite", "rhabdom", "pigment", "crystalline cone"]}
{"id": "paleo.006901", "title": "New anatomical information on Anomalocaris from the Cambrian Emu Bay Shale of South Australia and a reassessment of its inferred predatory habits", "abstract": "Two species of Anomalocaris co\u2010occur in the Emu Bay Shale (Cambrian Series 2, Stage 4) at Big Gully, Kangaroo Island. Frontal appendages of Anomalocaris briggsi Nedin, 1995, are more common than those of Anomalocaris cf. canadensis Whiteaves, 1892, at a quarry inland of the wave\u2010cut platform site from which these species were originally described. An oral cone has the three large, node\u2010bearing plates recently documented for Anomalocaris canadensis, confirming that Anomalocaris lacks a tetraradial \u2018Peytoia\u2019 oral cone and strengthening the case for the identity of the Australian specimens as Anomalocaris. Disarticulated anomalocaridid body flaps are more numerous in the Emu Bay Shale than in other localities, and they preserve anatomical details not recognized elsewhere. Transverse lines on the anterior part of the flaps, interpreted as strengthening rays or veins in previous descriptions of anomalocaridids, are associated with internal structures consisting of a series of well\u2010bounded, striated blocks or bars. Their structure is consistent with a structural function imparting strength to the body flaps. Setal structures consisting of a series of lanceolate blades are similar to those of other anomalocaridids and are found in isolation or associated with body flaps. A single specimen also preserves putative gut diverticula. The morphology of the appendages, oral cone, gut diverticula and compound eyes of Anomalocaris, along with its large size, suggests that it was an active predator, and specimens of coprolites containing trilobite fragments and trilobites with prominent injuries have been cited as evidence of anomalocaridid predation on trilobites. Based on frontal appendage morphology, Anomalocaris briggsi is inferred to have been a predator of soft\u2010bodied animals exclusively and only Anomalocaris cf. canadensis may have been capable of durophagous predation on trilobites, although predation (including possible cannibalism) by Redlichia could also explain the coprolites and damage to trilobite exoskeletons found in the Emu Bay Shale.", "keyphrases": ["anomalocaris", "emu bay shale", "frontal appendage", "coprolite"]}
{"id": "paleo.007599", "title": "Centimeter-wide worm-like fossils from the lowest Cambrian of South China", "abstract": "The trace fossil record implies that large worm-like animals were in place along with the skeletonizing organisms during the initial stage of the Cambrian explosion. Body fossils of large worms, however, have so far not been found. Here, we describe a large, soft-bodied, worm-like organism, Vittatusivermis annularius gen. et sp. nov. from the lowest Cambrian of South China, which is constrained to the Fortunian Age (541\u2013529 Ma) of the Cambrian Period. The elongate body of Vittatusivermis was large enough to have supported organ systems and a fluid skeleton that facilitated peristaltic locomotion, thus allowing for more complex patterns of movement than those of flatworms. Its occurrence on the same bedding surface as trace fossils suggests that Vittatusivermis might have produced epichnial trails and shallow burrows on and within sediments. Therefore, Vittatusivermis is likely to have been one of the long expected producers of trace fossils in the earliest Cambrian.", "keyphrases": ["south china", "place", "bilaterian", "large-sized bilaterian"]}
{"id": "paleo.006089", "title": "Interspecific interactions through 2 million years: are competitive outcomes predictable?", "abstract": "Ecological interactions affect the survival and reproduction of individuals. However, ecological interactions are notoriously difficult to measure in extinct populations, hindering our understanding of how the outcomes of interactions such as competition vary in time and influence long-term evolutionary changes. Here, the outcomes of spatial competition in a temporally continuous community over evolutionary timescales are presented for the first time. Our research domain is encrusting cheilostome bryozoans from the Wanganui Basin of New Zealand over a ca 2 Myr time period (Pleistocene to Recent). We find that a subset of species can be identified as consistent winners, and others as consistent losers, in the sense that they win or lose interspecific competitive encounters statistically more often than the null hypothesis of 50%. Most species do not improve or worsen in their competitive abilities through the 2 Myr period, but a minority of species are winners in some intervals and losers in others. We found that conspecifics tend to cluster spatially and interact more often than expected under a null hypothesis: most of these are stand-off interactions where the two colonies involved stopped growing at edges of encounter. Counterintuitively, competitive ability has no bearing on ecological dominance.", "keyphrases": ["outcome", "wanganui basin", "new zealand", "pleistocene", "colony"]}
{"id": "paleo.010207", "title": "On the Socio-Sexual Behaviour of the Extinct Ursid Indarctos arctoides: An Approach Based on Its Baculum Size and Morphology", "abstract": "The fossil bacula, or os penis, constitutes a rare subject of study due to its scarcity in the fossil record. In the present paper we describe five bacula attributed to the bear Indarctos arctoides Dep\u00e9ret, 1895 from the Batallones-3 site (Madrid Basin, Spain). Both the length and morphology of this fossil bacula enabled us to make interpretative approaches to a series of ecological and ethological characters of this bear. Thus, we suggest that I. arctoides could have had prolonged periods of intromission and/or maintenance of intromission during the post-ejaculatory intervals, a multi-male mating system and large home range sizes and/or lower population density. Its size might also have helped females to choose from among the available males.", "keyphrases": ["morphology", "bacula", "penis"]}
{"id": "10.1017/S1477201907002271", "title": "The phylogeny of the ornithischian dinosaurs", "abstract": "Synopsis Ornithischia is a familiar and diverse clade of dinosaurs whose global phylogeny has remained largely unaltered since early cladistic analyses in the mid 1980s. Current understanding of ornithischian evolution is hampered by a paucity of explicitly numerical phylogenetic analyses that consider the entire clade. As a result, it is difficult to assess the robustness of current phylogenetic hypotheses for Ornithischia and the effect that the addition of new taxa or characters is likely to have on the overall topology of the clade. The new phylogenetic analysis presented here incorporates a range of new basal taxa and characters in an attempt to rigorously test global ornithischian phylogeny. Parsimony analysis is carried out with 46 taxa and 221 characters. Although the strict component consensus tree shows poor resolution in a number of areas, application of reduced consensus methods provides a well\u2010resolved picture of ornithischian interrelationships. Surprisingly, Heterodontosauridae is placed as the most basal group of all well\u2010known ornithischians, phylogenetically distant from a stem\u2010defined Ornithopoda, creating a topology that is more congruent with the known ornithischian stratigraphical record. There is no evidence for a monophyletic \u2018Fabrosauridae\u2019, and Lesothosaurus (the best\u2010known \u2018fabrosaur') occupies an unusual position as the most basal member of Thyreophora. Other relationships within Thyreophora remain largely stable. The primitive thyreophoran Scelidosaurus is the sister taxon of Eurypoda (stegosaurs and ankylosaurs), rather than a basal ankylosaur as implied by some previous studies. The taxonomic content of Ornithopoda differs significantly from previous analyses and basal relationships within the clade are weakly supported, requiring further investigation. \u2018Hypsilopho\u2010dontidae\u2019 is paraphyletic, with some taxa (Agilisaurus, Hexinlusaurus, Othnielia) placed outside of Ornithopoda as non\u2010cerapodans. Ceratopsia and Pachycephalosauria are monophyletic and are united as Marginocephalia; however, the stability of these clades is reduced by a number of poorly preserved basal taxa. This analysis reaffirms much of the currently accepted ornithischian topology. Nevertheless, instability in the position and content of several clades (notably Heterodontosauridae and Ornithopoda) indicates that considerable future work on ornithischian phylogeny is required and causes problems for several current phylogenetic definitions.", "keyphrases": ["phylogeny", "ornithischian", "heterodontosauridae", "ankylosaur"]}
{"id": "paleo.003083", "title": "A new Late Jurassic turtle from Spain: phylogenetic implications, taphonomy and palaeoecology", "abstract": "Abstract:\u2002 The Jurassic was an important period in the evolution of Testudinata and encompasses the origin of many clades, and this is especially true of Jurassic turtles from Western Europe. A new genus and species of Late Jurassic turtle, Hispaniachelys prebetica gen. et sp. nov. from the upper Oxfordian of the Prebetic (Southern Spain), is described on the basis of postcranial material. The specimen is the only known tetrapod from the Mesozoic of the Prebetic and the oldest turtle from southern Europe. A mosaic of characters indicates this is a new genus: it displays basal features including dorsal epiplastral processes/reduced cleithra, no medial contact of the extragulars and a long first thoracic rib, alongside derived characters including an absence of mesoplastra and the vertebral 3/4 sulcus crossing neural 5. The phylogenetic position of the new taxon is hard to resolve, and it might be either a paracryptodire or a basal testudine, but it is distinct from Plesiochelys. A complex taphonomic history is shown by a range of overlying grazing traces and bioerosion on the carapace. The carapace was subsequently overturned and buried ventrally up, terminating grazing activity, and was then bored by sponges before final burial. Scanning electron microscopy reveals phosphatic microspheroids associated with bacterial decay in the vascular cavities of the cancellous bone, suggesting the carapace may have acted as a closed microenvironment in which decay\u2010derived authigenic minerals formed.", "keyphrases": ["late jurassic turtle", "new genus", "southern spain"]}
{"id": "paleo.010878", "title": "Hip extensor mechanics and the evolution of walking and climbing capabilities in humans, apes, and fossil hominins", "abstract": "Significance The evolution of humans\u2019 distinct bipedal gait remains a focus of research and debate. Many reconstructions of hominin locomotor evolution assume climbing capability trades off against walking economy, with improvement in one requiring diminishment of the other, but few have tested these functional inferences experimentally. In this study, we integrate experimental locomotor mechanics from humans and other primates with osteological measurements to assess the locomotor capabilities of early hominins. Our analyses show that changes in the ischium and hamstrings would have made walking more economical without reducing the utility of these muscles for climbing in early hominins. A wider set of evolutionary solutions may have been available to early hominins than previously recognized. The evolutionary emergence of humans\u2019 remarkably economical walking gait remains a focus of research and debate, but experimentally validated approaches linking locomotor capability to postcranial anatomy are limited. In this study, we integrated 3D morphometrics of hominoid pelvic shape with experimental measurements of hip kinematics and kinetics during walking and climbing, hamstring activity, and passive range of hip extension in humans, apes, and other primates to assess arboreal\u2013terrestrial trade-offs in ischium morphology among living taxa. We show that hamstring-powered hip extension during habitual walking and climbing in living apes and humans is strongly predicted, and likely constrained, by the relative length and orientation of the ischium. Ape pelves permit greater extensor moments at the hip, enhancing climbing capability, but limit their range of hip extension, resulting in a crouched gait. Human pelves reduce hip extensor moments but permit a greater degree of hip extension, which greatly improves walking economy (i.e., distance traveled/energy consumed). Applying these results to fossil pelves suggests that early hominins differed from both humans and extant apes in having an economical walking gait without sacrificing climbing capability. Ardipithecus was capable of nearly human-like hip extension during bipedal walking, but retained the capacity for powerful, ape-like hip extension during vertical climbing. Hip extension capability was essentially human-like in Australopithecus afarensis and Australopithecus africanus, suggesting an economical walking gait but reduced mechanical advantage for powered hip extension during climbing.", "keyphrases": ["ape", "economy", "vertical climbing"]}
{"id": "paleo.005640", "title": "All time high: Dimylidae (Eulipotyphla, Mammalia) diversity in the early Miocene locality of Ahn\u00edkov 1 (Czech Republic, MN 3)", "abstract": "The locality of Akn\u00edkov 1 (Czech Republic, MN 3) has yielded the largest diversity of Dimylidae known from a single locality. Four species are recognised in the few dozen recovered fossils: Dimylus aff. paradoxus, Plesiodimylus sp., Chainodus intercedens and Lacrimodon vandermeuleni nov. gen., nov. sp. The high diversity supports the assumption of a humid palaeoenvironment for Akn\u00edkov 1.", "keyphrases": ["dimylidae", "czech republic", "fragmented skull", "single tooth", "isolated element"]}
{"id": "10.2110/palo.2009.p09-011r", "title": "EFFECTS OF DATA CATEGORIZATION ON PALEOCOMMUNITY ANALYSIS: A CASE STUDY FROM THE PENNSYLVANIAN FINIS SHALE OF TEXAS", "abstract": "Abstract Paleocommunity research efforts have explored a multitude of faunal assemblages using a wide range of sampling and analytical methods to infer a paleoecological signal. Here, we derive six secondary datasets from a single stratigraphic series of faunal assemblages in the Finis Shale (Pennsylvanian) of Jacksboro, Texas, USA, using a variety of data categorization decisions (i.e., abundance versus calcified biomass, all taxa versus selected indicator taxa, and generic versus higher clade resolution). Biomass- and abundance-derived datasets were not significantly different in terms of evenness, Shannon's information index, or Simpson's diversity index. Using Bray-Curtis and nonmetric multidimensional scaling ordinations, with Sorenson and relative Sorenson distance measures, ordination axis scores of the six derived datasets were all significantly correlated with one another, suggesting little difference in their respective paleoecological signals. Three potential explanations for this consistent paleoecological signal, regardless of which data categorizations are employed, include: (1) the dominance of a few brachiopod taxa overwhelmingly influenced the community structure, (2) relatively constrained environmental conditions limited community variation, and (3) low variation in specimen size minimized potential differences among abundance and calcified biomass categorizations. We suggest that other datasets with greater diversities, greater evenness, or from a wider range of paleoenvironments might not show this consistency. Thus, to the degree possible and appropriate, paleoecological investigators should test the effects of these data categorization decisions on a paleoecological signal, regardless of the analytical method employed.", "keyphrases": ["finis shale", "texas", "brachiopod taxa"]}
{"id": "paleo.003440", "title": "A new phosphatic\u2010shelled cirripede (Crustacea, Thoracica) from the Lower Jurassic (Toarcian) of Germany \u2013 the oldest epiplanktonic barnacle", "abstract": "A new genus and species of phosphatic\u2010shelled eolepadid barnacle from the Posidonia Shale (Toarcian, falciferum Zone) of Zell u. Aichelberg, southern Germany, is described as Toarcolepas mutans gen. et sp. nov. Numerous disarticulated individuals, associated with fossil wood, are present in a piece of concretionary limestone, and these are interpreted as having lived epiplanktonically attached to driftwood. The taxonomy of the Late Triassic \u2013 Early Cretaceous family Eolepadidae is reviewed, and two further species (T. gaveyi (Withers, 1920) and T. lotharingica (M\u00e9chin, 1901)) are referred to Toarcolepas. The chemistry of valve composition of the Carboniferous Praelepas and Triassic\u2013Jurassic eolepadid cirripedes is investigated using X\u2010ray dispersive analysis, and the ubiquitous presence of abundant phosphorus is taken as evidence that these taxa had a primary phosphatic composition, now preserved as francolite. A significant change in shell chemistry from phosphate to calcium carbonate took place during the evolution of the Thoracica, during the Late Triassic or Early Jurassic. The driving force behind this change may have been related to the reduced predation pressure associated with acquisition of an epiplanktonic mode of life. Calcite is softer, but energetically cheaper to deposit than phosphate mineral phases.", "keyphrases": ["cirripede", "barnacle", "southern germany", "fossil wood"]}
{"id": "10.11646/palaeoentomology.4.6.1", "title": "Revision of Epigambriinae Handlirsch, stat. nov., a subfamily of Early Jurassic Ithonidae s.l. (Neuroptera)", "abstract": "We redescribe the holotype of Epigambria\u00a0longipennis Handlirsch, 1939 from the Early Jurassic of Dobbertin (Germany), the type of the family Epigambriidae Handlirsch, 1939. Two other early Toarcian genera from Germany (Polyosmylus Ansorge, 1996 from Grimmen and Rasnitsyneura gen. nov., the type species R. aequabilis (Bode, 1953), comb. nov. from Schandelach) are assigned to Epigambriidae, which we interpret as Epigambriinae, stat. nov., a subfamily of Ithonidae s.l. The venation of Epigambriinae is most similar to that of the polystoechotid genus-group but may be distinguished from members of this group mainly by (1) a single gradate series between branches of RP in both the fore- and hind wings, and (2) the absence of crossveins between branches of MP and CuA in the forewing.", "keyphrases": ["epigambriinae", "neuroptera", "grimmen"]}
{"id": "paleo.000582", "title": "The smallest known Devonian tetrapod shows unexpectedly derived features", "abstract": "A new genus and species of Devonian tetrapod, Brittagnathus minutus gen. et sp. nov., is described from a single complete right lower jaw ramus recovered from the Acanthostega mass-death deposit in the upper part of the Britta Dal Formation (upper Famennian) of Stensi\u00f6 Bjerg, Gauss Peninsula, East Greenland. Visualization by propagation phase contrast synchrotron microtomography allows a complete digital dissection of the specimen. With a total jaw ramus length of 44.8 mm, Brittagnathus is by far the smallest Devonian tetrapod described to date. It differs from all previously known Devonian tetrapods in having only a fang pair without a tooth row on the anterior coronoid and a large posterior process on the posterior coronoid. The presence of an incipient surangular crest and a concave prearticular margin to the adductor fossa together cause the fossa to face somewhat mesially, reminiscent of the condition in Carboniferous tetrapods. A phylogenetic analysis places Brittagnathus crownward to other Devonian tetrapods, adjacent to the Tournaisian genus Pederpes. Together with other recent discoveries, it suggests that diversification of \u2018Carboniferous-grade\u2019 tetrapods had already begun before the end of the Devonian and that the group was not greatly affected by the end-Devonian mass extinction.", "keyphrases": ["tetrapod", "brittagnathus", "acanthostega", "east greenland"]}
{"id": "10.1017/s0025315400029118", "title": "Biodiversity of Shallow-Water Red Sea Echinoids: Implications For the Fossil Record", "abstract": "Determination of fossil echinoid diversities is an important aspect of detailed palaeon- tological studies. The comparison of recent and fossil associations can be used to elucidate the problems of determination of fossil echinoid distributions. Actuopalaeontological studies of echinoids from the Red Sea (northern Bay of Safaga, Egypt) have shown that the study of fragments within bulk sediment samples greatly increased the possibilities for determining echinoid presence and distribution. The results show the restricted distribution as well as the differential preservation potential of the various echinoids. The distribution of echinoids is primarily controlled by grain size, food availability, exposure to current activity, and predation pressure. Regular and irregular sea-urchins show the expected disjunct distributions with the former showing a more undifferentiated distribution to various hard substrates. Irregular echinoids are tightly restricted to particular types of soft substrates reflecting their adaptation to the specific grain size of the sediments. Co-occurring irregular sea-urchins show a spatial differentiation into shallow (clypeasteroids) and deeper burrowers (spatangoids). This investigation shows that important echinoid species known to occur in the Red Sea are lacking or are very rare within the study area, although a large number of different facies types are present. Patchy distributions are present for both regular and irregular sea-urchins. The determination of biodiversity is therefore seen to be largely dependent on the scale of investigation. An important implication for fossil echinoid presence are the differential effects of taphonomic agents on the various test architectures. Some species are well represented due to their common occurrences, and their comparatively robust tests or test fragments.", "keyphrases": ["echinoid", "preservation potential", "biodiversity"]}
{"id": "10.1098/rstb.2020.0484", "title": "Riddles wrapped inside an enigma. Lupemban MSA technology as a rainforest adaptation: revisiting the lanceolate point", "abstract": "The Central African Stone Age is very poorly known when compared to the higher-resolution records of East and Southern Africa. Early Stone Age (ESA) archaeology is effectively absent from the rainforest zone, with the early Middle Stone Age (MSA) Lupemban industry representing the earliest sustained archaeological signature. Uranium-series dates of approximately 265 ka BP for the Lupemban at Twin Rivers (Zambia), although queried, suggest a precocious late Middle Pleistocene dispersal of early Homo sapiens into the equatorial rainforest belt. Lupemban palaeohabitat interactions and attendant behavioural and technological repertoires are key to its evolutionary significance, but investigation is hampered by the widespread vertical disturbance of stratigraphic profiles and the formation of \u2018stone-lines'. The Lupemban takes in a range of implement types and technologies, including core-axes, prepared core technology (PCT) points, blades and backed blades. But it is the elongated bifacial lanceolate point\u2014some exquisitely made and many exceeding 30 cm in length\u2014that defines the industry. Remarkably, unequivocal examples of these iconic artefacts have never been the focus of detailed techno-typological scrutiny. In this paper, I advance understanding of the Lupemban by initiating a re-consideration of lanceolate points at Kalambo Falls, Zambia, and discuss their implications for the Lupemban's evolutionary significance. This article is part of the theme issue \u2018Tropical forests in the deep human past\u2019.", "keyphrases": ["msa", "lanceolate point", "middle stone age", "technological repertoire"]}
{"id": "paleo.000538", "title": "Diverse Aquatic Adaptations in Nothosaurus spp. (Sauropterygia)\u2014Inferences from Humeral Histology and Microanatomy", "abstract": "Mid-diaphyseal cortical bone tissue in humeri of Nothosaurus spp. consists of coarse parallel-fibered bone, finer and higher organized parallel-fibered bone, and lamellar bone. Vascular canals are mainly arranged longitudinally and radially in a dominantly radial system. Blood vessels are represented by simple vascular canals, incompletely lined primary osteons, and fully developed primary osteons. Nothosaurus spp. shows a variety of diaphyseal microanatomical patterns, ranging from thick to very thin-walled cortices. In the early Anisian (Lower Muschelkalk), small- and large-bodied Nothosaurus spp. generally exhibit bone mass increase (BMI). In the middle to late Anisian (Middle Muschelkalk) small-bodied nothosaurs retain BMI whereas larger-bodied forms tend to show a decrease in bone mass (BMD). During the latest Anisian to early Ladinian (Upper Muschelkalk), small- and few large-bodied nothosaurs retain BMI, whereas the majority of large-bodied forms exhibit BMD. The stratigraphically youngest nothosaurs document five microanatomical categories, two of which are unique among marine amniotes: One consists of a very heterogeneously distributed spongy periosteal organization, the other of very thin-walled cortices. The functional significance of the two unique microanatomical specializations seen in large-bodied nothosaurs is the reduction of bone mass, which minimizes inertia of the limbs, and thus saves energy during locomotion. Transitions between the various microanatomical categories are rather gradual. Our results suggest that small-bodied Nothosaurus marchicus and other, not further assignable small-bodied nothosaurs seem to have been bound to near-shore, shallow marine environments throughout their evolution. Some large-bodied Nothosaurus spp. followed the same trend but others became more active swimmers and possibly inhabited open marine environments. The variety of microanatomical patterns may be related to taxonomic differences, developmental plasticity, and possibly sexual dimorphism. Humeral microanatomy documents the diversification of nothosaur species into different environments to avoid intraclade competition as well as competition with other marine reptiles. Nothosaur microanatomy indicates that knowledge of processes involved in secondary aquatic adaptation and their interaction are more complex than previously believed.", "keyphrases": ["microanatomy", "diversification", "secondary aquatic adaptation"]}
{"id": "10.5252/g2009n1a14", "title": "Taphonomy and palaeoecology of mid-Cretaceous amber-preserved microorganisms from southwestern France", "abstract": "ABSTRACT The investigation of microorganisms preserved in amber from Charente-Maritime (southwestern France) provides new insights into the mid-Cretaceous amber forest ecology. Amber from the localities of Archingeay-Les Nouillers and Cadeuil is unique due to the plethora of microinclusions and macroinclusions as well as the preservation of litter organisms. Soil microorganisms such as actinomycetes, sheathed prokaryotes, carnivorous fungi (Ascomycota), algae, testate amoebae and nematodes indicate that the resin solidified in terrestrial or limnetic-terrestrial microhabitats on the forest floor. Furthermore, arboreal and even marine microorganisms are preserved in the amber. This micro-assemblage suggests that the amber forest was located close to the sea shore or was at least temporarily under marine influence.", "keyphrases": ["microorganism", "southwestern france", "amber forest", "marine influence"]}
{"id": "paleo.007683", "title": "A New Crested Pterosaur from the Early Cretaceous of Spain: The First European Tapejarid (Pterodactyloidea: Azhdarchoidea)", "abstract": "Background The Tapejaridae is a group of unusual toothless pterosaurs characterized by bizarre cranial crests. From a paleoecological point of view, frugivorous feeding habits have often been suggested for one of its included clades, the Tapejarinae. So far, the presence of these intriguing flying reptiles has been unambiguously documented from Early Cretaceous sites in China and Brazil, where pterosaur fossils are less rare and fragmentary than in similarly-aged European strata. Methodology/Principal Findings Europejara olcadesorum gen. et sp. nov. is diagnosed by a unique combination of characters including an unusual caudally recurved dentary crest. It represents the oldest known member of Tapejaridae and the oldest known toothless pterosaur. The new taxon documents the earliest stage of the acquisition of this anatomical feature during the evolutionary history of the Pterodactyloidea. This innovation may have been linked to the development of new feeding strategies. Conclusion/Significance The discovery of Europejara in the Barremian of the Iberian Peninsula reveals an earlier and broader global distribution of tapejarids, suggesting a Eurasian origin of this group. It adds to the poorly known pterosaur fauna of the Las Hoyas locality and contributes to a better understanding of the paleoecology of this Konservat-Lagerst\u00e4tte. Finally, the significance of a probable contribution of tapejarine tapejarids to the early angiosperm dispersal is discussed.", "keyphrases": ["spain", "pterodactyloidea", "china", "brazil", "strata"]}
{"id": "paleo.009121", "title": "Possible Further Evidence of Low Genetic Diversity in the El Sidr\u00f3n (Asturias, Spain) Neandertal Group: Congenital Clefts of the Atlas", "abstract": "We present here the first cases in Neandertals of congenital clefts of the arch of the atlas. Two atlases from El Sidr\u00f3n, northern Spain, present respectively a defect of the posterior (frequency in extant modern human populations ranging from 0.73% to 3.84%), and anterior (frequency in extant modern human populations ranging from 0.087% to 0.1%) arch, a condition in most cases not associated with any clinical manifestation. The fact that two out of three observable atlases present a low frequency congenital condition, together with previously reported evidence of retained deciduous mandibular canine in two out of ten dentitions from El Sidr\u00f3n, supports the previous observation based on genetic evidence that these Neandertals constituted a group with close genetic relations. Some have proposed for humans and other species that the presence of skeletal congenital conditions, although without clinical significance, could be used as a signal of endogamy or inbreeding. In the present case this interpretation would fit the general scenario of high incidence of rare conditions among Pleistocene humans and the specific scenariothat emerges from Neandertal paleogenetics, which points to long-term small and decreasing population size with reduced and isolated groups. Adverse environmental factors affecting early pregnancies would constitute an alternative, non-exclusive, explanation for a high incidence of congenital conditions. Further support or rejection of these interpretations will come from new genetic and skeletal evidence from Neandertal remains.", "keyphrases": ["atlas", "modern human population", "endogamy"]}
{"id": "paleo.010865", "title": "Iterative Evolution of Sympatric Seacow (Dugongidae, Sirenia) Assemblages during the Past \u223c26 Million Years", "abstract": "Extant sirenians show allopatric distributions throughout most of their range. However, their fossil record shows evidence of multispecies communities throughout most of the past \u223c26 million years, in different oceanic basins. Morphological differences among co-occurring sirenian taxa suggest that resource partitioning played a role in structuring these communities. We examined body size and ecomorphological differences (e.g., rostral deflection and tusk morphology) among sirenian assemblages from the late Oligocene of Florida, early Miocene of India and early Pliocene of Mexico; each with three species of the family Dugongidae. Although overlapping in several ecomorphological traits, each assemblage showed at least one dominant trait in which coexisting species differed. Fossil sirenian occurrences occasionally are monotypic, but the assemblages analyzed herein show iterative evolution of multispecies communities, a phenomenon unparalleled in extant sirenian ecology. As primary consumers of seagrasses, these communities likely had a strong impact on past seagrass ecology and diversity, although the sparse fossil record of seagrasses limits direct comparisons. Nonetheless, our results provide robust support for previous suggestions that some sirenians in these extinct assemblages served as keystone species, controlling the dominance of climax seagrass species, permitting more taxonomically diverse seagrass beds (and sirenian communities) than many of those observed today.", "keyphrases": ["oligocene", "sirenian community", "iterative evolution"]}
{"id": "10.1111/zsc.12223", "title": "Tortoise (Reptilia, Testudinidae) radiations in Southern Africa from the Eocene to the present", "abstract": "Africa, inclusive of the West Indian Ocean islands, harbours 11 of the world's 16 extant testudinid genera. Fossil records indicate that testudinids originated in Asia and dispersed first to North America and Europe (Early Eocene) and later to Africa (Late Eocene). We used mitochondrial (1870 bp) and nuclear (1416 bp) DNA sequence data to assess whether molecular data support the late cladogenesis of Southern African testudinid lineages. Our results revealed strong support for the monophyly of a clade consisting of Kinixys, the two Malagasy genera and four Southern African genera (Psammobates, Stigmochelys, Homopus and Chersina). Kinixys diverged from this clade in the Late Palaeocene, suggesting that testudinids occupied Africa at an earlier date than indicated by fossil records. The Southern African tortoises consist of three, strongly supported clades: Psammobates + Stigmochelys; the five\u2010toed Homopus + Chersina; and the four\u2010toed Homopus. Due to the paraphyly of Homopus, we propose the taxonomic resurrection of Chersobius for the five\u2010toed Homopus species (boulengeri, signatus and solus). Cladogenesis at the genus level occurred mainly in the Eocene, with Chersina and Chersobius diverging in the Oligocene. The latter divergence coincided with species\u2010level radiations within Homopus (areolatus and femoralis) and Psammobates (oculifer, geometricus and tentorius). Our phylogeny could not resolve relationships within Psammobates, indicating rapid speciation between the Late Oligocene and Early Miocene. The Chersobius species were the last to diverge in the Early to Mid\u2010Miocene. By the Mid\u2010Miocene, P. tentorius started to differentiate into four lineages instead of the three recognized subspecies: P. t. tentorius, P. t. trimeni and two P. t. verroxii subclades occurring north and south of the Orange River, respectively. Terminal radiations in several taxa suggest the existence of cryptic species and a more diverse tortoise fauna than currently recognized. Factors contributing to this diversity may include the early origin of African testudinids and climatic fluctuations over a heterogeneous landscape.", "keyphrases": ["testudinid genera", "late eocene", "tortoise"]}
{"id": "paleo.000433", "title": "Bone Histology in Dysalotosaurus lettowvorbecki (Ornithischia: Iguanodontia) \u2013 Variation, Growth, and Implications", "abstract": "Background Dysalotosaurus lettowvorbecki is a small ornithopod dinosaur known from thousands of bones and several ontogenetic stages. It was found in a single locality within the Tendaguru Formation of southeastern Tanzania, possibly representing a single herd. Dysalotosaurus provides an excellent case study for examining variation in bone microstructure and life history and helps to unravel the still mysterious growth pattern of small ornithopods. Methodology/Principal Findings Five different skeletal elements were sampled, revealing microstructural variation between individuals, skeletal elements, cross sectional units, and ontogenetic stages. The bone wall consists of fibrolamellar bone with strong variability in vascularization and development of growth cycles. Larger bones with a high degree of utilization have high relative growth rates and seldom annuli/LAGs, whereas small and less intensively used bones have lower growth rates and a higher number of these resting lines. Due to the scarcity of annuli/LAGs, the reconstruction of the life history of Dysalotosaurus was carried out using regularly developed and alternating slow and fast growing zones. Dysalotosaurus was a precocial dinosaur, which experienced sexual maturity at ten years, had an indeterminate growth pattern, and maximum growth rates comparable to a large kangaroo. Conclusions/Significance The variation in the bone histology of Dysalotosaurus demonstrates the influence of size, utilization, and shape of bones on relative growth rates. Annuli/LAGs are not the only type of annual growth cycles that can be used to reconstruct the life history of fossil vertebrates, but the degree of development of these lines may be of importance for the reconstruction of paleobehavior. The regular development of annuli/LAGs in subadults and adults of large ornithopods therefore reflects higher seasonal stress due to higher food demands, migration, and altricial breeding behavior. Small ornithopods often lack regularly developed annuli/LAGs due to lower food demands, no need for migration, and precocial behavior.", "keyphrases": ["ontogenetic stage", "sexual maturity", "bone histology", "non-avian dinosaur", "high number"]}
{"id": "10.3389/fevo.2017.00037", "title": "The Development of the Silurian Trilobite Aulacopleura koninckii Reconstructed by Applying Inferred Growth and Segmentation Dynamics: A Case Study in Paleo-Evo-Devo", "abstract": "Fossilized growth series provide rare glimpses into the development of ancient organisms, illustrating descriptively how size and shape changed through ontogeny. Occasionally fossil preservation is such that it is feasible to test alternative possibilities about how ancient development was regulated. Here we apply inferred developmental parameters pertaining to size, shape, and segmentation in the abundant and well-preserved 429 Myr old trilobite Aulacopleura koninckii that we have investigated previously to reconstruct the post-embryonic ontogeny of this ancient arthropod. Our published morphometric analyses associated with model testing have shown that: specification of the adult number of trunk segments (polymorphic in this species) was determined precociously in ontogeny; that growth regulation was targeted (i.e., compensatory), such that each developmental stage exhibited comparable variance in size and shape; and that growth gradients operating along the main body axis, both during juvenile and adult ontogeny, resulted from a form of growth control based on positional specification. While such developmental features are common among extant organisms, our results represent the oldest evidence for them within Metazoa. Herein, the novel reconstruction of the development of A. koninckii permits visualization of patterns of relative and absolute growth and segmentation as never before possible for a fossilized arthropod ontogeny. By conducting morphometric analysis of appropriate data sets it is thus possible to move beyond descriptive ontogenetic studies and to address questions of high interest for evolutionary developmental biology using data from fossils, which can help elucidate both how developmental processes themselves evolve and how they affect the evolution of organismal body patterning. By extending similar analyses to other cases of exceptional preservation of fossilized ontogeny, we can anticipate beginning to realize the research program of \u201cpaleo-evo-devo\u201d.", "keyphrases": ["segmentation", "ontogeny", "arthropod"]}
{"id": "10.1130/G23889A.1", "title": "A Paleocene lowland macroflora from Patagonia reveals significantly greater richness than North American analogs", "abstract": "Few South American macrofloras of Paleocene age are known, and this limits our knowledge of diversity and composition between the end-Cretaceous event and the Eocene appearance of high floral diversity. We report new, unbiased collections of 2516 compression specimens from the Paleocene Salamanca Formation (ca. 61.7 Ma) from two localities in the Palacio de los Loros exposures in southern Chubut, Patagonia, Argentina. Our samples reveal considerably greater richness than was previously known from the Paleocene of Patagonia, including 36 species of angiosperm leaves as well as angiosperm fruits, flowers, and seeds; ferns; and conifer leaves, cones, and seeds. The floras, which are from siltstone and sandstone channel-fills deposited on low-relief floodplain landscapes in a humid, warm temperate climate, are climatically and paleoenvironmentally comparable to many quantitatively collected Paleocene floras from the Western Interior of North America. Adjusted for sample size, there are >50% more species at each Palacio de los Loros quarry than in any comparable U.S. Paleocene sample. These results indicate more vibrant terrestrial ecosystems in Patagonian than in North American floodplain environments \u223c4 m.y. after the end-Cretaceous extinction, and they push back the time line 10 m.y. for the evolution of high floral diversity in South America. The cause of the dis parity is unknown but could involve reduced impact effects because of greater distance from the Chicxulub site, higher latest Cretaceous diversity, or faster recovery or immigration rates.", "keyphrases": ["floral diversity", "los loros", "southern chubut", "great richness"]}
{"id": "10.1144/M35.6", "title": "Chapter 6 Phanerozoic palaeoenvironment and palaeolithofacies maps of the Arctic region", "abstract": "Abstract Sixty-three maps illustrate geodynamic evolution and development of palaeoenvironments and palaeolithofacies of the Circum-Arctic region during Phanerozoic times. After the break-up of Rodinia and Pannotia in the Early Palaeozoic, the major Arctic plates Baltica, Siberia and Laurentia drifted from their original position around the South Pole towards the Supercontinent Pangea, which existed in the equatorial position during Late Palaeozoic and Early Mesozoic times. During the Mesozoic and Cenozoic plates gathered around newly formed Arctic Ocean. Large continental masses were assembled from major plates and numerous small plates and terranes on the northern hemisphere and around the North Pole. All the continents were by now connected. Carbonates were abundant in Siberia and Laurentia during Palaeozoic times. Clastic sedimentation prevailed during Mesozoic and Cenozoic times. The distribution of lithofacies shows climatic change associated with continental assembly and disassembly as well as with the steady northward drift of the continents.", "keyphrases": ["map", "palaeogeographic reconstruction", "schematic geological map", "middle callovian", "hohnstein -gps"]}
{"id": "10.1111/gbi.12178", "title": "Environmental context for the terminal Ediacaran biomineralization of animals", "abstract": "In terminal Ediacaran strata of South China, the onset of calcareous biomineralization is preserved in the paleontological transition from Conotubus to Cloudina in repetitious limestone facies of the Dengying Formation. Both fossils have similar size, funnel\u2010in\u2010funnel construction, and epibenthic lifestyle, but Cloudina is biomineralized, whereas Conotubus is not. To provide environmental context for this evolutionary milestone, we conducted a high\u2010resolution elemental and stable isotope study of the richly fossiliferous Gaojiashan Member. Coincident with the first appearance of Cloudina is a significant positive carbonate carbon isotope excursion (up to +6\u2030) and an increase in the abundance and 34S composition of pyrite. In contrast, \u03b434S values of carbonate\u2010associated sulfate remain steady throughout the succession, resulting in anomalously large (>70\u2030) sulfur isotope fractionations in the lower half of the member. The fractionation trend likely relates to changes in microbial communities, with sulfur disproportionation involved in the lower interval, whereas microbial sulfate reduction was the principal metabolic pathway in the upper. We speculate that the coupled paleontological and biogeochemical anomalies may have coincided with an increase in terrestrial weathering fluxes of sulfate, alkalinity, and nutrients to the depositional basin, which stimulated primary productivity, the spread of an oxygen minimum zone, and the development of euxinic conditions in subtidal and basinal environments. Enhanced production and burial of organic matter is thus directly connected to the carbon isotope anomaly, and likely promoted pyritization as the main taphonomic pathway for Conotubus and other soft\u2010bodied Ediacara biotas. Our studies suggest that the Ediacaran confluence of ecological pressures from predation and environmental pressures from an increase in seawater alkalinity set the stage for an unprecedented geobiological response: the evolutionary novelty of animal biomineralization.", "keyphrases": ["south china", "dengying formation", "environmental context"]}
{"id": "paleo.008504", "title": "Carcharocles-Bitten Odontocete Caudal Vertebrae from the Coastal Eastern United States", "abstract": "A description and analysis is given of three Neogene odontocete caudal vertebrae that were bitten by the extinct megatooth sharks Carcharocles megalodon or Carcharocles chubutensis . The peduncular caudal vertebrae show bilateral gouge marks consistent with having been actively bitten and wedged between adjacent teeth of C. megalodon or C. chubutensis . None of the vertebrae show signs of healing. The occurrence of bite marks on distal caudals suggests active predation (vs. scavenging) in order to immobilize even relatively small prey prior to consumption.", "keyphrases": ["odontocete caudal vertebrae", "shark", "carcharocles"]}
{"id": "10.1098/rstb.2012.0115", "title": "Hominin cognitive evolution: identifying patterns and processes in the fossil and archaeological record", "abstract": "As only limited insight into behaviour is available from the archaeological record, much of our understanding of historical changes in human cognition is restricted to identifying changes in brain size and architecture. Using both absolute and residual brain size estimates, we show that hominin brain evolution was likely to be the result of a mix of processes; punctuated changes at approximately 100 kya, 1 Mya and 1.8 Mya are supplemented by gradual within-lineage changes in Homo erectus and Homo sapiens sensu lato. While brain size increase in Homo in Africa is a gradual process, migration of hominins into Eurasia is associated with step changes at approximately 400 kya and approximately 100 kya. We then demonstrate that periods of rapid change in hominin brain size are not temporally associated with changes in environmental unpredictability or with long-term palaeoclimate trends. Thus, we argue that commonly used global sea level or Indian Ocean dust palaeoclimate records provide little evidence for either the variability selection or aridity hypotheses explaining changes in hominin brain size. Brain size change at approximately 100 kya is coincident with demographic change and the appearance of fully modern language. However, gaps remain in our understanding of the external pressures driving encephalization, which will only be filled by novel applications of the fossil, palaeoclimatic and archaeological records.", "keyphrases": ["archaeological record", "behaviour", "brain size", "language", "encephalization"]}
{"id": "10.1144/SP358.14", "title": "Geological and anthropogenic controls on the sampling of the terrestrial fossil record: a case study from the Dinosauria", "abstract": "Abstract Dinosaurs provide excellent opportunities to examine the impact of sampling biases on the palaeodiversity of terrestrial organisms. The stratigraphical and geographical ranges of 847 dinosaurian species are analysed for palaeodiversity patterns and compared to several sampling metrics. The observed diversity of dinosaurs, Theropoda, Sauropodomorpha and Ornithischia, are positively correlated with sampling at global and regional scales. Sampling metrics for the same region correlate with each other, suggesting that different metrics often capture the same signal. Regional sampling metrics perform well as explanations for regional diversity patterns, but correlations with global diversity are weaker. Residual diversity estimates indicate that sauropodomorphs diversified during the Late Triassic, but major increases in the diversity of theropods and ornithischians did not occur until the Early Jurassic. Diversity increased during the Jurassic, but many groups underwent extinction during the Late Jurassic or at the Jurassic/Cretaceous boundary. Although a recovery occurred during the Cretaceous, only sauropodomorphs display a long-term upward trend. The Campanian\u2013Maastrichtian diversity \u2018peak\u2019 is largely a sampling artefact. There is little evidence for a gradualistic decrease in diversity prior to the end-Cretaceous mass extinction (except for ornithischians), and when such decreases do occur they are small relative to those experienced earlier in dinosaur evolution. Supplementary material: The full data set and details of analyses are available at www.geolsoc.org.uk/SUP18487 The same materials (in the form of an Excel workbook) are also available from the first author on request.", "keyphrases": ["sampling", "signal", "artefact"]}
{"id": "paleo.005488", "title": "A remarkable short-snouted horned dinosaur from the Late Cretaceous (late Campanian) of southern Laramidia", "abstract": "The fossil record of centrosaurine ceratopsids is largely restricted to the northern region of western North America (Alberta, Montana and Alaska). Exceptions consist of single taxa from Utah (Diabloceratops) and China (Sinoceratops), plus otherwise fragmentary remains from the southern Western Interior of North America. Here, we describe a remarkable new taxon, Nasutoceratops titusi n. gen. et sp., from the late Campanian Kaiparowits Formation of Utah, represented by multiple specimens, including a nearly complete skull and partial postcranial skeleton. Autapomorphies include an enlarged narial region, pneumatic nasal ornamentation, abbreviated snout and elongate, rostrolaterally directed supraorbital horncores. The subrectangular parietosquamosal frill is relatively unadorned and broadest in the mid-region. A phylogenetic analysis indicates that Nasutoceratops is the sister taxon to Avaceratops, and that a previously unknown subclade of centrosaurines branched off early in the group's history and persisted for several million years during the late Campanian. As the first well-represented southern centrosaurine comparable in age to the bulk of northern forms, Nasutoceratops provides strong support for the provincialism hypothesis, which posits that Laramidia\u2014the western landmass formed by inundation of the central region of North America by the Western Interior Seaway\u2014hosted at least two coeval dinosaur communities for over a million years of late Campanian time.", "keyphrases": ["late campanian", "laramidia", "centrosaurine", "avaceratops"]}
{"id": "paleo.012641", "title": "First Shark from the Late Devonian (Frasnian) Gogo Formation, Western Australia Sheds New Light on the Development of Tessellated Calcified Cartilage", "abstract": "Background Living gnathostomes (jawed vertebrates) comprise two divisions, Chondrichthyes (cartilaginous fishes, including euchondrichthyans with prismatic calcified cartilage, and extinct stem chondrichthyans) and Osteichthyes (bony fishes including tetrapods). Most of the early chondrichthyan (\u2018shark\u2019) record is based upon isolated teeth, spines, and scales, with the oldest articulated sharks that exhibit major diagnostic characters of the group\u2014prismatic calcified cartilage and pelvic claspers in males\u2014being from the latest Devonian, c. 360 Mya. This paucity of information about early chondrichthyan anatomy is mainly due to their lack of endoskeletal bone and consequent low preservation potential. Methodology/Principal Findings Here we present new data from the first well-preserved chondrichthyan fossil from the early Late Devonian (ca. 380\u2013384 Mya) Gogo Formation L\u00e4gerstatte of Western Australia. The specimen is the first Devonian shark body fossil to be acid-prepared, revealing the endoskeletal elements as three-dimensional undistorted units: Meckel\u2019s cartilages, nasal, ceratohyal, basibranchial and possible epibranchial cartilages, plus left and right scapulocoracoids, as well as teeth and scales. This unique specimen is assigned to Gogoselachus lynnbeazleyae n. gen. n. sp. Conclusions/Significance The Meckel\u2019s cartilages show a jaw articulation surface dominated by an expansive cotylus, and a small mandibular knob, an unusual condition for chondrichthyans. The scapulocoracoid of the new specimen shows evidence of two pectoral fin basal articulation facets, differing from the standard condition for early gnathostomes which have either one or three articulations. The tooth structure is intermediate between the \u2018primitive\u2019 ctenacanthiform and symmoriiform condition, and more derived forms with a euselachian-type base. Of special interest is the highly distinctive type of calcified cartilage forming the endoskeleton, comprising multiple layers of nonprismatic subpolygonal tesserae separated by a cellular matrix, interpreted as a transitional step toward the tessellated prismatic calcified cartilage that is recognized as the main diagnostic character of the chondrichthyans.", "keyphrases": ["frasnian", "gogo formation", "epibranchial cartilage", "tooth"]}
{"id": "paleo.008489", "title": "Pteropoda (Mollusca, Gastropoda, Thecosomata) from the Paleocene-Eocene Thermal Maximum (United States Atlantic Coastal Plain)", "abstract": "The response of many organisms to the Paleocene-Eocene Thermal Maximum (PETM; ~56 Ma) has been documented, but marine mollusks are not known from any deposits of that age. For the first time, we describe a PETM assemblage of pteropods (planktic mollusks), consisting of six species representing three genera (Altaspiratella, Heliconoides and Limacina). Four species could be identified to species level, and one of these, Limacina novacaesarea sp. nov., is described as new. Only the genus Heliconoides was previously known from pre-Eocene sediments, with a single Campanian specimen and one latest Paleocene species. We recovered pteropods from the Marlboro Clay (United States Atlantic Coastal Plain), deposited at paleodepths from inner shelf (southern Salisbury Embayment) to middle-outer shelf (New Jersey Coastal Plain). Most living pteropod assemblages inhabit water depths of 200 m or more, so their occurrence at shelf depths may reflect transport from more open waters. During the PETM, pH in the upper waters of the ocean may have declined, but this did not cause dissolution of pteropods before they reached the seafloor, possibly due to buffering in coastal waters. The apparently sudden appearance of three genera could reflect better preservation due to high sedimentation rates, since the underlying and overlying formations show poor preservation of calcareous microfossils. Potential ancestors, however, have not been found anywhere, so we consider it more likely that the rapid environmental changes during the PETM, such as temperature, runoff and nutrient fluxes, and ocean water chemistry, may have triggered pteropod diversification.", "keyphrases": ["paleocene-eocene thermal maximum", "pteropod", "ocean"]}
{"id": "10.1080/02724634.2017.1354006", "title": "Evolutionary Implications of Tooth Attachment Versus Tooth Implantation: A Case Study Using Dinosaur, Crocodilian, and Mammal Teeth", "abstract": "ABSTRACT \n Tooth attachment and implantation are two classical descriptors of dental anatomy. Tooth attachment distinguishes between teeth that are either fused to the jaw by bone, or suspended within a socket by a periodontal ligament. Tooth implantation describes the geometry of this attachment and has been broadly divided into acrodonty, pleurodonty, and thecodonty. Among extant amniotes, only mammals and crocodilians are considered truly thecodont, because they possess a complex attachment system that includes a periodontal ligament and true tooth sockets. These two amniote groups diverged from a common ancestor over 300 million years ago and are thought to have evolved thecodonty independently. This view has recently come under a great deal of scrutiny with the discovery of complex tooth attachment systems, including the presence of a ligamentous tooth attachment in numerous non-mammalian, non-crocodilian amniotes. This has spurred debate and inconsistencies over the conventional usage of tooth attachment and implantation categories and their evolutionary significance. We provide a comparative histological approach for describing tooth attachment and implantation in an exemplary, traditionally thecodont taxonomic group: the non-avian dinosaurs. The comparisons between theropod, hadrosaurid, and ceratopsid teeth show that all dinosaurs have ligamentous tooth attachments composed of identical dental tissues to those in mammals and crocodilians, but they show a diverse array of tooth attachment geometries, replacement modes, and bone architectures supporting the dentition. The methodology we follow allows researchers to tease apart phylogenetically and functionally significant features of tooth attachment and implantation that could be used in future studies.", "keyphrases": ["crocodilian", "geometry", "amniote", "non-avian dinosaur", "tissue"]}
{"id": "10.5194/cp-12-455-2016", "title": "A Model-Model and Data-Model Comparison for the Early Eocene Hydrological Cycle", "abstract": "Abstract. A range of proxy observations have recently provided constraints on how Earth's hydrological cycle responded to early Eocene climatic changes. However, comparisons of proxy data to general circulation model (GCM) simulated hydrology are limited and inter-model variability remains poorly characterised. In this work, we undertake an intercomparison of GCM-derived precipitation and P\u2009\u2212\u2009E distributions within the extended EoMIP ensemble (Eocene Modelling Intercomparison Project; Lunt et al., 2012), which includes previously published early Eocene simulations performed using five GCMs differing in boundary conditions, model structure, and precipitation-relevant parameterisation schemes. We show that an intensified hydrological cycle, manifested in enhanced global precipitation and evaporation rates, is simulated for all Eocene simulations relative to the preindustrial conditions. This is primarily due to elevated atmospheric paleo-CO2, resulting in elevated temperatures, although the effects of differences in paleogeography and ice sheets are also important in some models. For a given CO2 level, globally averaged precipitation rates vary widely between models, largely arising from different simulated surface air temperatures. Models with a similar global sensitivity of precipitation rate to temperature (dP\u2215dT) display different regional precipitation responses for a given temperature change. Regions that are particularly sensitive to model choice include the South Pacific, tropical Africa, and the Peri-Tethys, which may represent targets for future proxy acquisition. A comparison of early and middle Eocene leaf-fossil-derived precipitation estimates with the GCM output illustrates that GCMs generally underestimate precipitation rates at high latitudes, although a possible seasonal bias of the proxies cannot be excluded. Models which warm these regions, either via elevated CO2 or by varying poorly constrained model parameter values, are most successful in simulating a match with geologic data. Further data from low-latitude regions and better constraints on early Eocene CO2 are now required to discriminate between these model simulations given the large error bars on paleoprecipitation estimates. Given the clear differences between simulated precipitation distributions within the ensemble, our results suggest that paleohydrological data offer an independent means by which to evaluate model skill for warm climates.", "keyphrases": ["hydrological cycle", "proxy data", "early eocene simulation", "global precipitation", "high latitude"]}
{"id": "10.1098/rsos.171669", "title": "A critical revision of the fossil record, stratigraphy and diversity of the Neogene seal genus Monotherium (Carnivora, Phocidae)", "abstract": "Historically, Monotherium had been one of the few genera of extinct Phocidae (true seals) that served as a wastebin taxon. Consequently, it did neither aid in understanding phylogenetic relationships of extinct Phocidae, nor in understanding seal diversity in deep time. This urged the reassessment of the genus. Before our review, Monotherium included five different species: Monotherium aberratum, Monotherium affine, and Monotherium delognii from Belgium; Monotherium gaudini from Italy; and Monotherium? wymani from the east coast USA. In this work we redescribe the fossil record of the genus, retaining the type species M. delognii. Monotherium aberratum and M. affine are reassigned to the new phocine genus Frisiphoca. Monotherium gaudini is renamed and considered a stem-monachine (Noriphoca gaudini). The holotype of the monachine M.? wymani requires further study pending the discovery of new fossil material that could be attributed to the same taxon. Reinvestigating the stratigraphic context reveals that N. gaudini most likely represents one of the two oldest named phocid seals, or even the oldest, dated to the late Oligocene\u2013earliest Miocene. Our results allow questioning the widespread idea that Phocidae originated in the western Atlantic and better appreciate their palaeobiogeography during the late Oligocene\u2013Miocene interval in the North Atlantic realm.", "keyphrases": ["seal", "phocidae", "miocene"]}
{"id": "10.1017/S1477201907002428", "title": "Middle Jurassic Praeaulacidae (Insecta: Hymenoptera: Evanioidea) of Inner Mongolia and Kazakhstan", "abstract": "Synopsis Sixteen new and one undetermined species within six genera, of which two are recognised as new, referable to Praeaulacidae are described from the Middle Jurassic Daohugou deposits of Ningcheng, Inner Mongolia, China. They are Praeaulacus orientalis sp.nov.,Praeaulacus daohugouen\u2010sis sp. nov., Praeaulacus exquisitus sp. nov., Praeaulacus scabratus sp. nov., Praeaulacus sculptus sp. nov., Praeaulacus robustus sp. nov., Praeaulacus afflatus sp. nov., Praeaulacon ningchengensis sp. nov., Praeaulacon elegantulus sp. nov., Aulacogastrinus insculptus sp. nov., Aulacogastrinus longaciculatus sp. nov., Aulacogastrinus hebeiensis sp. nov., Aulacogastrinus sp., Sinaulacogast\u2010rinus eucallus gen. et sp. nov., Eosaulacus giganteus gen. et sp. nov. and Eosaulacus granulatus gen. et sp. nov. within Praeaulacinae, and Anomopterella huangi sp. nov. within Anomopterellinae. In addition, a new species, Nevania karatau sp. nov., assigned to Nevaniinae is reported from the Late Jurassic Karabastau Formation of Karatau, southern Kazakhstan. A key to known taxa within Praeaulacinae and Anomopterellinae, respectively, is presented. The presence of five common genera between the Daohugou and Karatau faunas indicates a close relationship between the two regions. Both a high attachment of metasoma on propodeum and a quite high diversity in the Praeaulacidae in the Middle Jurassic indicate that the Evanioidea probably emerged as early as in the Early Jurassic. The Anomopterellinae were parasitic on xylophages like Praeaulacinae.", "keyphrases": ["praeaulacidae", "kazakhstan", "anomopterellinae"]}
{"id": "10.1146/annurev-marine-121916-063359", "title": "Manifestation, Drivers, and Emergence of Open Ocean Deoxygenation.", "abstract": "Oxygen loss in the ocean, termed deoxygenation, is a major consequence of climate change and is exacerbated by other aspects of global change. An average global loss of 2% or more has been recorded in the open ocean over the past 50-100 years, but with greater oxygen declines in intermediate waters (100-600 m) of the North Pacific, the East Pacific, tropical waters, and the Southern Ocean. Although ocean warming contributions to oxygen declines through a reduction in oxygen solubility and stratification effects on ventilation are reasonably well understood, it has been a major challenge to identify drivers and modifying factors that explain different regional patterns, especially in the tropical oceans. Changes in respiration, circulation (including upwelling), nutrient inputs, and possibly methane release contribute to oxygen loss, often indirectly through stimulation of biological production and biological consumption. Microbes mediate many feedbacks in oxygen minimum zones that can either exacerbate or ameliorate deoxygenation via interacting nitrogen, sulfur, and carbon cycles. The paleo-record reflects drivers of and feedbacks to deoxygenation that have played out through the Phanerozoic on centennial, millennial, and hundred-million-year timescales. Natural oxygen variability has made it difficult to detect the emergence of a climate-forced signal of oxygen loss, but new modeling efforts now project emergence to occur in many areas in 15-25 years. Continued global deoxygenation is projected for the next 100 or more years under most emissions scenarios, but with regional heterogeneity. Notably, even small changes in oxygenation can have significant biological effects. New efforts to systematically observe oxygen changes throughout the open ocean are needed to help address gaps in understanding of ocean deoxygenation patterns and drivers.", "keyphrases": ["emergence", "deoxygenation", "oxygen loss", "climate change"]}
{"id": "paleo.000531", "title": "Keratin Durability Has Implications for the Fossil Record: Results from a 10 Year Feather Degradation Experiment", "abstract": "Keratinous \u2018soft tissue\u2019 structures (i.e. epidermally derived and originally non-biomineralized), include feathers, skin, claws, beaks, and hair. Despite their relatively common occurrence in the fossil record (second only to bone and teeth), few studies have addressed natural degradation processes that must occur in all organic material, including those keratinous structures that are incorporated into the rock record as fossils. Because feathers have high preservation potential and strong phylogenetic signal, in the current study we examine feathers subjected to different burial environments for a duration of ~10 years, using transmission electron microscopy (TEM) and in situ immunofluorescence (IF). We use morphology and persistence of specific immunoreactivity as indicators of preservation at the molecular and microstructural levels. We show that feather keratin is durable, demonstrates structural and microstructural integrity, and retains epitopes suitable for specific antibody recognition in even the harshest conditions. These data support the hypothesis that keratin antibody reactivity can be used to identify the nature and composition of epidermal structures in the rock record, and to address evolutionary questions by distinguishing between alpha- (widely distributed) and beta- (limited to sauropsids) keratin.", "keyphrases": ["feather", "high preservation potential", "keratin"]}
{"id": "paleo.005791", "title": "\"Dinosaur\" petroglyphs at Kachina Bridge site, Natural Bridges National Monument, southeastern Utah: not dinosaurs after all", "abstract": "Bridge is what appears to be an unambiguous depiction of a sauropod dinosaur, herein called Dinosaur 1. Because mainstream science has produced no alternate explanation for Dinosaur 1, it has become an important weapon in the arsenal of the anti-evolution movement. The movement's proponents claim that it demonstrates the coexistence of humans and dinosaurs, thus casting doubt on the geological time scale of millions of years. Until now that claim has gone unchallenged. The hypothesis that a given petroglyph depicts a dinosaur predicts that the image is not a composite; depicts an animal; has features that cannot be reconciled with non-dinosaurian local fauna; has features of a specific, identifiable dinosaur; and is entirely human-made. These predictions were tested for Dinosaur 1 and three other alleged dinosaur petroglyphs at Kachina Bridge by on-site visual examination under varying light conditions. Examination reveals that the \"neck\" and \"back\" of Dinosaur 1 are a composite of two separate petroglyphs, and its \"legs\" are a natural mud or mineral stain. A second alleged sauropod petroglyph is a mere mud stain. The other two alleged dinosaur petroglyphs are human-made, but neither depicts an animal. The four Kachina Bridge \"dinosaurs\" are illusions produced by pareidolia. None of them satisfy the predictions of the hypothesis that a dinosaur is depicted. Dinosaur 1-heretofore a creationist poster child-and its counterparts now join the plethora of discredited \"evidence\" for the ancient coexistence of humans and dinosaurs.", "keyphrases": ["petroglyph", "kachina bridge", "leg", "mineral stain"]}
{"id": "10.1017/S0022336000026998", "title": "Chronostratigraphy and \u201cLand-Mammal Ages\u201d in the Cenozoic of southern South America: principles, practices, and the \u201cUquian\u201d problem", "abstract": "The concept of \u201cland-mammal age\u201d as developed in South America is examined. The \u201cUquian Land-mammal age\u201d is used as a study case. \u201cLand-mammal age\u201d parataxonomy is here considered methodologically but not conceptually different from chronostratigraphic taxonomy. \u201cLand-mammal ages\u201d in South America are based on stages. However, we consider that accurate biostratigraphic studies must be done in South America for establishing the biostratigraphy and precise boundary stratotypes of most stages-ages. The Uquia outcrops are here considered inadequate as a stratotype. A new South American continental stage-age is proposed. This stage is based on a biostratigraphic scheme. The stratotypes of the stage and biozones are located in the fossiliferous southeastern Buenos Aires Province marine cliffs. The lower boundary stratotype is proposed. The stage-age is probably correlated with the Gauss Chron and the lower Matuyama Chron. Additionally, some major units of Ameghino are validated and a different timing for the arrival of North American mammals to southern South America is presented.", "keyphrases": ["southern south america", "unit", "ameghino"]}
{"id": "paleo.001835", "title": "Revision of the Late Jurassic teleosaurid genus Machimosaurus (Crocodylomorpha, Thalattosuchia)", "abstract": "Machimosaurus was a large-bodied genus of teleosaurid crocodylomorph, considered to have been durophagous/chelonivorous, and which frequented coastal marine/estuarine ecosystems during the Late Jurassic. Here, we revise the genus based on previously described specimens and revise the species within this genus. We conclude that there were three European Machimosaurus species and another taxon in Ethiopia. This conclusion is based on numerous lines of evidence: craniomandibular, dental and postcranial morphologies; differences in estimated total body length; geological age; geographical distribution; and hypothetical lifestyle. We re-diagnose the type species Machimosaurus hugii and limit referred specimens to only those from Upper Kimmeridgian\u2013Lower Tithonian of Switzerland, Portugal and Spain. We also re-diagnose Machimosaurus mosae, demonstrate that it is an available name and restrict the species to the uppermost Kimmeridgian\u2013lowermost Tithonian of northeastern France. We re-diagnose and validate the species Machimosaurus nowackianus from Harrar, Ethiopia. Finally, we establish a new species, Machimosaurus buffetauti, for the Lower Kimmeridgian specimens of France and Germany (and possibly England and Poland). We hypothesize that Machimosaurus may have been analogous to the Pliocene\u2013Holocene genus Crocodylus in having one large-bodied taxon suited to traversing marine barriers and additional, geographically limited taxa across its range.", "keyphrases": ["jurassic", "teleosaurid", "crocodylomorph"]}
{"id": "paleo.010407", "title": "Fossil Dolphin Otekaikea marplesi (Latest Oligocene, New Zealand) Expands the Morphological and Taxonomic Diversity of Oligocene Cetaceans", "abstract": "The Oligocene Epoch was a time of major radiation of the Odontoceti (echolocating toothed whales, dolphins). Fossils reveal many odontocete lineages and considerable structural diversity, but whether the clades include some crown taxa or only archaic groups is contentious. The New Zealand fossil dolphin \u201cProsqualodon\u201d marplesi (latest Oligocene, \u226523.9 Ma) is here identified as a crown odontocete that represents a new genus, Otekaikea, and adds to the generic diversity of Oligocene odontocetes. Otekaikea marplesi is known only from the holotype, which comprises a partial skeleton from the marine Otekaike Limestone of the Waitaki Valley. Otekaikea marplesi was about 2.5 m long; it had procumbent anterior teeth, and a broad dished face for the nasofacial muscles implicated in production of echolocation sounds. The prominent condyles and unfused cervical vertebrae suggest a flexible neck. A phylogenetic analysis based on morphological features places Otekaikea marplesi in the extinct group Waipatiidae, within the clade Platanistoidea. The phylogeny implies an Oligocene origin for the lineage now represented by the endangered Ganges River dolphin (Platanista gangetica), supporting an Oligocene history for the crown Odontoceti.", "keyphrases": ["otekaikea marplesi", "new zealand", "prosqualodon", "new genus", "phylogenetic analysis"]}
{"id": "paleo.004664", "title": "Dynamics of dental evolution in ornithopod dinosaurs", "abstract": "Ornithopods were key herbivorous dinosaurs in Mesozoic terrestrial ecosystems, with a variety of tooth morphologies. Several clades, especially the \u2018duck-billed\u2019 hadrosaurids, became hugely diverse and abundant almost worldwide. Yet their evolutionary dynamics have been disputed, particularly whether they diversified in response to events in plant evolution. Here we focus on their remarkable dietary adaptations, using tooth and jaw characters to examine changes in dental disparity and evolutionary rate. Ornithopods explored different areas of dental morphospace throughout their evolution, showing a long-term expansion. There were four major evolutionary rate increases, the first among basal iguanodontians in the Middle-Late Jurassic, and the three others among the Hadrosauridae, above and below the split of their two major clades, in the middle of the Late Cretaceous. These evolutionary bursts do not correspond to times of plant diversification, including the radiation of the flowering plants, and suggest that dental innovation rather than coevolution with major plant clades was a major driver in ornithopod evolution.", "keyphrases": ["ornithopod", "hadrosaurid", "dental disparity", "dynamic"]}
{"id": "10.1098/rspb.2012.0683", "title": "Phylogenomic datasets provide both precision and accuracy in estimating the timescale of placental mammal phylogeny", "abstract": "The fossil record suggests a rapid radiation of placental mammals following the Cretaceous\u2013Paleogene (K\u2013Pg) mass extinction 65 million years ago (Ma); nevertheless, molecular time estimates, while highly variable, are generally much older. Early molecular studies suffer from inadequate dating methods, reliance on the molecular clock, and simplistic and over-confident interpretations of the fossil record. More recent studies have used Bayesian dating methods that circumvent those issues, but the use of limited data has led to large estimation uncertainties, precluding a decisive conclusion on the timing of mammalian diversifications. Here we use a powerful Bayesian method to analyse 36 nuclear genomes and 274 mitochondrial genomes (20.6 million base pairs), combined with robust but flexible fossil calibrations. Our posterior time estimates suggest that marsupials diverged from eutherians 168\u2013178 Ma, and crown Marsupialia diverged 64\u201384 Ma. Placentalia diverged 88\u201390 Ma, and present-day placental orders (except Primates and Xenarthra) originated in a \u223c20 Myr window (45\u201365 Ma) after the K\u2013Pg extinction. Therefore we reject a pre K\u2013Pg model of placental ordinal diversification. We suggest other infamous instances of mismatch between molecular and palaeontological divergence time estimates will be resolved with this same approach.", "keyphrases": ["molecular study", "fossil calibration", "placentalia"]}
{"id": "10.1146/annurev.ecolsys.32.081501.114113", "title": "Evolutionary Patterns Among Permo-Triassic Therapsids*", "abstract": "\u25aa Abstract\u2002A rich fossil record documents nonmammalian evolution. In recent years, the application of cladistic methodology has shed valuable light on the relationships within the therapsid clades Biarmosuchia, Dinocephalia, Anomodontia, and Cynodontia. Recent discoveries from South Africa suggest that Gondwana, rather than Laurasia, was the center of origin and radiation for many early therapsids. Because of their relative abundance and global distribution, therapsids have enjoyed widespread use in biostratigraphy, basin analysis, and paleo-environmental and -continental reconstructions. Synapsids (including therapsids) form the bulk of tetrapod diversity (in terms of both number of species and abundance) from Early Permian to Middle Triassic times and thus can provide critical information on the nature of the Permo-Triassic extinction in the terrestrial realm. Quantitative techniques have produced headway into understanding the relative importance of homoplasy and convergent evolution in the origin of m...", "keyphrases": ["therapsid", "cynodontia", "permian"]}
{"id": "10.1080/02724634.2017.1366916", "title": "A New Stem Odontocete from the Late Oligocene Pysht Formation in Washington State, U.S.A.", "abstract": "ABSTRACT \n Odontocetes first appear in the fossil record during the early Oligocene and soon after show a near-worldwide distribution. However, little is still known of their early diversity, especially in the North Pacific Region. A new taxon of stem odontocete with heterodont dentition, Olympicetus avitus, gen. et sp. nov., is described herein from the upper Oligocene Pysht Formation in Washington State, U.S.A. The material consists of two partial skulls belonging to a juvenile and a neonate and includes part of the dentition and a tympanic bulla. Olympicetus shares many similarities with the Oligocene odontocetes Simocetus rayi and Ashleycetus planicapitis but displays a combination of characters that distinguish it from these and other coeval taxa. A phylogenetic analysis shows Olympicetus in a polytomy with Xenorophidae, a clade of early high-frequency-hearing odontocetes mainly known from the western Atlantic. Furthermore, Olympicetus displays characters that can be considered as structural proxies for echolocation, such as having premaxillary sac fossae and the maxilla expanded over the frontal. In addition to Olympicetus, other marine tetrapods from the Pysht Formation include marine birds, desmostylians, pinnipeds, and early mysticetes, giving us a unique insight into late Oligocene marine tetrapod faunas of the North Pacific.", "keyphrases": ["oligocene pysht formation", "phylogenetic analysis", "xenorophidae"]}
{"id": "10.1146/annurev-earth-040809-152402", "title": "Evolution of Grasses and Grassland Ecosystems", "abstract": "The evolution and subsequent ecological expansion of grasses (Poaceae) since the Late Cretaceous have resulted in the establishment of one of Earth's dominant biomes, the temperate and tropical grasslands, at the expense of forests. In the past decades, several new approaches have been applied to the fossil record of grasses to elucidate the patterns and processes of this ecosystem transformation. The data indicate that the development of grassland ecosystems on most continents was a multistage process involving the Paleogene appearance of (C3 and C4) open-habitat grasses, the mid-late Cenozoic spread of C3 grass-dominated habitats, and, finally, the Late Neogene expansion of C4 grasses at tropical-subtropical latitudes. The evolution of herbivores adapted to grasslands did not necessarily coincide with the spread of open-habitat grasses. In addition, the timing of these evolutionary and ecological events varied between regions. Consequently, region-by-region investigations using both direct (plant fossil...", "keyphrases": ["grass", "grassland", "spread"]}
{"id": "10.1080/14772019.2011.630927", "title": "The phylogeny of Tetanurae (Dinosauria: Theropoda)", "abstract": "Tetanuran theropods represent the majority of Mesozoic predatory dinosaur diversity and the lineage leading to extant Aves. Thus their history is relevant to understanding the evolution of dinosaur diversity, Mesozoic terrestrial ecosystems, and modern birds. Previously, the fragmentary and poorly sampled fossil record of basal (non-coelurosaur) tetanurans led to uncertainties regarding their basic interrelationships. This in turn prevented determining the relationships of many incompletely known taxa that nonetheless document a global radiation spanning more than 120 million years. We undertook an exhaustive examination of all basal tetanurans and all existing character data, taking advantage of recent discoveries and adding new morphological, temporal and geographic data. Our cladistic analysis of 61 taxa achieved significantly improved phylogenetic resolution. These results position several \u2018stem\u2019 taxa basal to a succession of monophyletic clades (Megalosauroidea, Allosauroidea and Coelurosauria). Megalosauroids include nearly 20 taxa arrayed amongst a basalmost clade (Piatnitzkysauridae, fam. nov.) and the sister taxa Spinosauridae and Megalosauridae; the latter includes two subfamilies, Megalosaurinae and Afrovenatorinae subfam. nov. Allosauroidea contains a diverse Metriacanthosauridae (= Sinraptoridae), Neovenatoridae, Carcharodontosauridae and a reduced Allosauridae. Finally, we assessed more than 40 fragmentary forms and hundreds of additional reported tetanuran occurrences. Tetanuran evolution was characterized by repeated acquisitions of giant body size and at least two general skull forms, but few variations in locomotor morphology. Despite parallel diversification of multiple lineages, there is evidence for a succession of \u2018dominant\u2019 clades. Tetanurae first appeared by the Early Jurassic and was globally distributed by the Middle Jurassic. Several major clades appeared prior to the breakup of Pangaea; as such their absence in specific regions, and at later times, must be due to poor sampling, dispersal failure and/or regional extinction. Finally, we outline a general perspective on Mesozoic terrestrial biogeography that should apply to most clades that appeared before the Late Jurassic.", "keyphrases": ["tetanurae", "tetanurans", "megalosauroidea", "major clade"]}
{"id": "paleo.005055", "title": "The revival of a so-called rotten fish: the ontogeny of the Devonian acanthodian Triazeugacanthus", "abstract": "Since its original description as a chordate, the Late Devonian Scaumenella mesacanthi has been interpreted alternately as a prochordate, a larval ostracoderm and an immature acanthodian. For the past 30 years, these minute specimens were generally considered as decayed acanthodians, most of them belonging to Triazeugacanthus affinis. Among the abundant material of \u2018Scaumenella\u2019, we identified a size series of 188 specimens of Triazeugacanthus based on otolith characteristics. Despite taphonomic alteration, we describe proportional growth and progressive appearance of skeletal elements through size increase. Three ontogenetic stages are identified based on squamation extent, ossification completion and allometric growth. We demonstrate that what has been interpreted previously as various degrees of decomposition corresponds to ontogenetic changes.", "keyphrases": ["ontogeny", "triazeugacanthus", "skeletal element"]}
{"id": "paleo.008138", "title": "Horseshoe crab phylogeny and independent colonizations of fresh water: ecological invasion as a driver for morphological innovation", "abstract": "Xiphosurids are an archaic group of aquatic chelicerate arthropods, generally known by the colloquial misnomer of \u2018horseshoe crabs\u2019. Known from marine environments as far back as the early Ordovician, horseshoe crabs are generally considered \u2018living fossils\u2019 \u2013 descendants of a bradytelic lineage exhibiting little morphological or ecological variation throughout geological time. However, xiphosurids are known from freshwater sediments in the Palaeozoic and Mesozoic; furthermore, the contention that xiphosurids show little morphological variation has never been tested empirically. Attempts to test this are hampered by the lack of a modern phylogenetic framework with which to explore different evolutionary scenarios. Here, I present a phylogenetic analysis of Xiphosurida and explore patterns of morphospace and environmental occupation of the group throughout the Phanerozoic. Xiphosurids are shown to have invaded non\u2010marine environments independently at least five times throughout their evolutionary history, twice resulting in the radiation of major clades \u2013 bellinurines and austrolimulids \u2013 that occupied novel regions of morphospace. These clades show a convergent ecological pattern of differentiation, speciation and subsequent extinction. Horseshoe crabs are shown to have a more dynamic and complex evolutionary history than previously supposed, with the extant species representing only a fraction of the group's past ecological and morphological diversity.", "keyphrases": ["independent colonization", "mesozoic", "phylogenetic analysis", "xiphosurida", "horseshoe crab"]}
{"id": "paleo.000724", "title": "Bolide impact triggered the Late Triassic extinction event in equatorial Panthalassa", "abstract": "Extinctions within major pelagic groups (e.g., radiolarians and conodonts) occurred in a stepwise fashion during the last 15 Myr of the Triassic. Although a marked decline in the diversity of pelagic faunas began at the end of the middle Norian, the cause of the middle Norian extinction is uncertain. Here we show a possible link between the end-middle Norian radiolarian extinction and a bolide impact. Two palaeoenvironmental events occurred during the initial phase of the radiolarian extinction interval:\n(1) a post-impact shutdown of primary and biogenic silica production within a time span of 10 4 -10 5 yr, and (2) a sustained reduction in the sinking flux of radiolarian silica for ~0.3 Myr after the impact. The catastrophic collapse of the pelagic ecosystem at this time was probably the dominant factor responsible for the end-middle Norian conodont extinction.", "keyphrases": ["late triassic", "bolide impact", "strong biotic turnover", "extraterrestrial impact(s", "conodont diversity change"]}
{"id": "10.1371/journal.pone.0071428", "title": "Direct Comparisons of 2D and 3D Dental Microwear Proxies in Extant Herbivorous and Carnivorous Mammals", "abstract": "The analysis of dental microwear is commonly used by paleontologists and anthropologists to clarify the diets of extinct species, including herbivorous and carnivorous mammals. Currently, there are numerous methods employed to quantify dental microwear, varying in the types of microscopes used, magnifications, and the characterization of wear in both two dimensions and three dimensions. Results from dental microwear studies utilizing different methods are not directly comparable and human quantification of wear features (e.g., pits and scratches) introduces interobserver error, with higher error being produced by less experienced individuals. Dental microwear texture analysis (DMTA), which analyzes microwear features in three dimensions, alleviates some of the problems surrounding two-dimensional microwear methods by reducing observer bias. Here, we assess the accuracy and comparability within and between 2D and 3D dental microwear analyses in herbivorous and carnivorous mammals at the same magnification. Specifically, we compare observer-generated 2D microwear data from photosimulations of the identical scanned areas of DMTA in extant African bovids and carnivorans using a scanning white light confocal microscope at 100x magnification. Using this magnification, dental microwear features quantified in 2D were able to separate grazing and frugivorous bovids using scratch frequency; however, DMTA variables were better able to discriminate between disparate dietary niches in both carnivorous and herbivorous mammals. Further, results demonstrate significant interobserver differences in 2D microwear data, with the microwear index remaining the least variable between experienced observers, consistent with prior research. Overall, our results highlight the importance of reducing observer error and analyzing dental microwear in three dimensions in order to consistently interpret diets accurately.", "keyphrases": ["carnivorous mammal", "pit", "microwear texture analysis", "dmta", "dietary niche"]}
{"id": "paleo.006305", "title": "Nanostructure of biogenic versus abiogenic calcium carbonate crystals", "abstract": "The mineral phase of the aragonite skeletal fibers of extant scleractinians (Favia, Goniastrea) examined with Atomic Force Microscope (AFM) consists entirely of grains ca. 50-100 nm in diameter separated from each other by spaces of a few nanometers. A similar pattern of nanograin arrangement was observed in basal calcite skeleton of extant calcareous sponges (Petrobiona) and aragonitic extant stylasterid coralla (Adelopora). Aragonite fibers of the fossil scleractinians: Neogene Paracyathus (Korytnica, Poland), Cretaceous Rennensismilia (Gosau, Austria), Trochocyathus (Black Hills, South Dakota, USA), Jurassic Isastraea (Ostromice, Poland), and unidentified Triassic tropiastraeid (Alpe di Specie, Italy) are also nanogranular, though boundaries between individual grains occasionally are not well resolved. On the other hand, in diagenetically altered coralla (fibrous skeleton beside aragonite bears distinct calcite signals) of the Triassic corals from Alakir Cay, Turkey (Pachysolenia), a typical nanogranular pattern is not recognizable. Also aragonite crystals produced synthetically in sterile environment did not exhibit a nanogranular pattern. Unexpectedly, nanograins were recognized in some crystals of sparry calcite regarded as abiotically precipitated. Our findings support the idea that nanogranular organization of calcium carbonate fibers is not, per se, evidence of their biogenic versus abiogenic origin or their aragonitic versus calcitic composition but rather, a feature of CaCO 3 formed in an aqueous solution in the presence of organic molecules that control nanograin formation. Consistent orientation of crystalographic axes of polycrystalline skeletal fibers in extant or fossil coralla, suggests that nanograins are monocrystalline and crystallographically ordered (at least after deposition). A distinctly granular versus an unresolvable pattern of nano-organization of CaCO 3 fibers seems to correspond, respectively, to an original versus a diagenetically depleted amount of organic matter bounding a mineral phase; this is consistent with qualitative and quantitative analyses of organic matter content in extant and fossil skeletons.", "keyphrases": ["biogenic", "crystal", "organic matter"]}
{"id": "paleo.012097", "title": "Trabecular Evidence for a Human-Like Gait in Australopithecus africanus", "abstract": "Although the earliest known hominins were apparently upright bipeds, there has been mixed evidence whether particular species of hominins including those in the genus Australopithecus walked with relatively extended hips, knees and ankles like modern humans, or with more flexed lower limb joints like apes when bipedal. Here we demonstrate in chimpanzees and humans a highly predictable and sensitive relationship between the orientation of the ankle joint during loading and the principal orientation of trabecular bone struts in the distal tibia that function to withstand compressive forces within the joint. Analyses of the orientation of these struts using microCT scans in a sample of fossil tibiae from the site of Sterkfontein, of which two are assigned to Australopithecus africanus, indicate that these hominins primarily loaded their ankles in a relatively extended posture like modern humans and unlike chimpanzees. In other respects, however, trabecular properties in Au africanus are distinctive, with values that mostly fall between those of chimpanzees and humans. These results indicate that Au. africanus, like Homo, walked with an efficient, extended lower limb.", "keyphrases": ["australopithecus", "ankle", "chimpanzee", "orientation"]}
{"id": "paleo.011184", "title": "Tapeworm Eggs in a 270 Million-Year-Old Shark Coprolite", "abstract": "Remains of parasites in vertebrates are rare from the Mesozoic and Paleozoic. Once most parasites that live in \u2013 or pass through \u2013 the gastrointestinal tract of vertebrates, fossil feces (coprolites) or even intestinal contents (enterolites) can eventually preserve their remains. Here we announce the discovery of a spiral shark coprolite from the Paleozoic bearing a cluster of 93 small oval-elliptical smooth-shelled structures, interpreted as eggs of a tapeworm.The eggs were found in a thin section of an elasmobranch coprolite. Most of the eggs are filled by pyrite and some have a special polar swelling (operculum), suggesting they are non-erupted eggs. One of the eggs contains a probable developing larva. The eggs are approximately 145\u2013155 \u00b5m in length and 88\u2013100 \u00b5m in width and vary little in size within the cluster. The depositional and morphological features of the eggs closely resemble those of cestodes. Not only do the individual eggs have features of extant tapeworms, but their deposition all together in an elongate segment is typical to modern tapeworm eggs deposited in mature segments (proglottids). This is the earliest fossil record of tapeworm parasitism of vertebrates and establishes a timeline for the evolution of cestodes. This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was hitherto known and that the interaction between tapeworms and vertebrates occurred at least since the Middle-Late Permian.", "keyphrases": ["egg", "coprolite", "parasitism", "intestinal parasite", "predation"]}
{"id": "10.2110/palo.2009.p09-164r", "title": "FOSSIL VERTEBRATE TRACKS AS PALEOPENETROMETERS: CONFOUNDING EFFECTS OF FOOT MORPHOLOGY", "abstract": "Abstract The depth to which a vertebrate track is indented can provide a wealth of information, being a direct result of the weight, duty factor, and limb kinematics of the animal as well as media (\u200a=\u200a substrate or sediment) consistency. In order to recreate the formation of the track and elucidate media consistency at the time of track formation, such factors as animal mass, duty factor, and foot morphology must be taken into consideration. This study uses Finite Element Analysis and physical modeling to demonstrate for the first time that the shape of the foot is an important factor that influences the depth to which the sediment is penetrated. In cohesive sediment, less compact morphology allows more sediment to move vertically upwards at the edges of the foot, dissipating force at the surface, and retarding transmission of load vertically down into the sediment. The reverse of this effect is seen in noncohesive sediment. Foot morphology, therefore, has a direct impact on preservation potential, both of surface tracks and undertracks, that is irrespective of the pressure exerted on the sediment surface by the foot and independent of mass and duty factor.", "keyphrases": ["foot morphology", "substrate", "track formation"]}
{"id": "10.1130/G38583.1", "title": "Quantifying the rise of the Himalaya orogen and implications for the South Asian monsoon", "abstract": "We reconstruct the rise of a segment of the southern flank of the Himalaya-Tibet orogen, to the south of the Lhasa terrane, using a paleoaltimeter based on paleoenthalpy encoded in fossil leaves from two new assemblages in southern Tibet (Liuqu and Qiabulin) and four previously known floras from the Himalaya foreland basin. U-Pb dating of zircons constrains the Liuqu flora to the latest Paleocene (ca. 56 Ma) and the Qiabulin flora to the earliest Miocene (21- 19 Ma). The proto-Himalaya grew slowly against a high (similar to 4 km) proto-Tibetan Plateau from similar to 1 km in the late Paleocene to similar to 2.3 km at the beginning of the Miocene, and achieved at least similar to 5.5 km by ca. 15 Ma. Contrasting precipitation patterns between the Himalaya-Tibet edifice and the Himalaya foreland basin for the past similar to 56 m.y. show progressive drying across southern Tibet, seemingly linked to the uplift of the Himalaya orogen.", "keyphrases": ["south", "early miocene", "vegetation change", "himalayan orogeny"]}
{"id": "10.1111/j.1095-8312.2003.00302.x", "title": "Phylogeny and biogeography of Caribbean mammals", "abstract": "Vicariance and dispersal hypotheses have been proposed over the last two hundred years to explain the distribution, diversity, and faunal composition of the Caribbean biota. Despite great advances in understanding the geological history of the region, recent biogeographical reviews have not used historical biogeographical methods. In this paper I review the taxonomy, distribution and phylogeny of all Cenozoic Caribbean non-volant mammals and four bat lineages, and present reconciled trees for available phylogenies. Dates available from the fossil record and hypotheses of divergence based on molecular phylogenetic studies are also included in general assessments of fit between proposed geological models and Caribbean mammal diversification. The evidence posited in mammalian phylogenies does not add to the argument of dispersal vs. vicariance. One previously unidentified temporal pattern, the colonization of the Caribbean by South American mammals between the Palaeocene and the Middle Miocene, accounts for the distribution and phylogeny of the majority of lineages studied. Choloepodine and megalocnine sloths, hystricognath rodents, and primates all arrived during this window of colonization. Of these, megalocnine sloths, hystricognath rodents, Brachyphylla and allied bats, Stenodermatina bats, and primates fit the pattern of divergence from the mainland implied by the Gaarlandia hypothesis. Sloths, rodents and primates also roughly fit the timing of arrival to the Caribbean implied by Gaarlandia. The remaining taxa show contradictory dates of divergence according to molecular clock estimates, and no taxa fit the predicted timing and pattern of divergence among Antillean landmasses under the Gaarlandia model. Choloepodine sloths, murid rodents, insectivorans, mormoopids, and natalids show patterns of divergence from the mainland that are inconsistent with the Gaarlandia hypothesis and seem to require taxon-specific biogeographical explanations.", "keyphrases": ["colonization", "rodent", "phylogeny"]}
{"id": "paleo.005268", "title": "An exceptional record of Cambrian trilobite moulting behaviour preserved in the Emu Bay Shale, South Australia", "abstract": "Trilobites dominate the Emu Bay Shale (EBS) assemblage (Cambrian Series 2, Stage 4, South Australia) in terms of numbers, with Estaingia bilobata Pocock 1964 being extremely abundant, and the larger Redlichia takooensis Lu 1950, being common. Many specimens within the EBS represent complete moulted exoskeletons, which is unusual for Cambrian fossil deposits. The abundance of complete moults provides an excellent record that has allowed the recognition of various recurrent moult configurations for both species, enabling the inference of movement sequences required to produce such arrangements. Moult configurations of E. bilobata are characterized by slight displacement of the joined rostral plate and librigenae, often accompanied by detachment of the cranidium, suggesting ecdysis was achieved by anterior withdrawal via opening of the cephalic sutures. Moulting in R. takooensis often followed the same method, but configurations show greater displacement of cephalic sclerites, suggesting more vigorous movement by the animal during moulting. Both species also show rare examples of Salter's configuration, with the entire cephalon anteriorly inverted, and several other unusual configurations. These results indicate that moulting in trilobites was a more variable process than originally thought. In contrast, other Cambrian Konservat-Lagerst\u20ac atten with an abundance of trilobites (e.g. Wheeler Shale, USA, and Mount Stephen Trilobite Beds, Canada) show larger numbers of 'axial shields' and isolated sclerites, often interpreted as disarticulated exuviae. This points to a higher level of disturbance from factors, such as animal activity, depositional processes or water movement, compared to that of the EBS, where quiescent conditions and intermittent seafloor anoxia contributed to an unparalleled trilobite moulting record. \u25a1 Burgess Shale, Cambrian, ecdysis, Emu Bay Shale, Lagerst\u20ac atten, moult configuration, trilobite.", "keyphrases": ["trilobite", "emu bay shale", "exoskeleton", "moult configuration", "cranidium"]}
{"id": "paleo.005884", "title": "An Early Neogene Elasmobranch fauna from the southern Caribbean (Western Venezuela)", "abstract": "The Cantaure Formation (Burdigalian to ?early Langhian) is located in the Falc\u00f3n Basin, North Western Venezuela, and includes one of the most diverse Neogene teleostean and benthonic invertebrate faunas in Tropical America. The paleoenvironmental preferences of the members of this fauna, as well as published paleogeographic reconstructions, suggest that the Cantaure Formation was deposited in a highly-productive shallow water environment, associated with coastal upwelling. We documented a paleodiversity of 39 shark and ray species, including 15 previously unreported taxa for Venezuela and six for Tropical America. We performed a bathymetric analysis of the fossil assemblage based on the distribution of closely-related extant chondrichthyan relatives of fossil taxa and discuss the ecological role and stratigraphic significance of the latter. Our results support the hypothesis that the Cantaure Formation was deposited in an insular inner-middle shelf environment. The elasmobranch fauna is characterized by a predominance of benthopelagic sharks with piscivorous feeding preferences (e.g., \u2020Paratodus, Galeorhinus, Hemipristis, Rhizoprionodon, Carcharhinus, Isogomphodon, Negaprion, \u2020Physogaleus and Sphyrna) followed by durophagous/cancritrophic feeders (e.g., Heterodontus, Nebrius, Mustelus, Rhynchobatus, Pristis, Dasyatis, cf. Pteroplatytrygon, cf. Taeniurops, Aetobatus, Aetomylaeus and Rhinoptera). Filter (e.g., Mobula and \u2020Plinthicus), eurytrophic/sarcophagous (e.g., \u2020Carcharocles and Galeocerdo) and teuthitrophic (e.g., Alopias) feeder species were also found. Teeth of Carcharocles megalodon found in Burdigalian sediments of the Cantaure Formation support the presence of this species already in the early Miocene. Some taxa (Nebrius, Carcharhinus cf. C. macloti and Rhynchobatus) are absent from the extant Caribbean and Western Atlantic fauna, but were present in the region before the closure of the Central American Seaway.", "keyphrases": ["shark", "aetomylaeus", "carcharocles megalodon", "cetacean bone", "otodontidae"]}
{"id": "paleo.006347", "title": "The gladiuses in coleoid cephalopods: homology, parallelism, or convergence?", "abstract": "In the cephalopod subclass Coleoidea, several homology problems exist, mainly owing to unsolved phylogenetic relationships between decabrachian orders. The present contribution reviews the ''similarity'' of the gladius, the chitinous shell rudiment in the dorsal mantle that provides rigid attachment sites for the locomotory-relevant musculature. As a secretion product of the shell sac epithelium as well as in the light of a common three-layered construction, both the octobrachian and the decabrachian gladius types most probably represent homologues with identical developmental mechanisms; ''similarities'' in gladius shapes in unrelated lineages therefore should be considered as the result of parallelism. Ultrastructural comparisons with Mesozoic coleoids suggest that an organic gladius is actually embedded in every proostracum-bearing phragmocone. It is therefore generally accepted that a gladius evolved through decalcification of a proostracum-bearing phragmocone. The character ''gladius'' accordingly represents a plesiomorphy within pro-ostracum-bearing coleoids. Whereas the gladius of Vampyroteuthis as well as the octopod fin supports indirectly derived from phragmoteuthid-like phragmocone via Mesozoic gladius types, the decabrachian gladius types can morphogenetically be linked with various ancestral groups (Belemnitida, Diplobelida, Groenlandibelidae, Vasseuria, Belosepiella). Experimental decalcification of a sepiid cuttlebone demonstrates furthermore that a gladius might have also evolved from a secondarily proostracum-less phragmocone. Life styles and habitats of living and Mesozoic gladius-bearing octobrachians are finally discussed in the light of our conclusions.", "keyphrases": ["coleoid", "parallelism", "gladius"]}
{"id": "paleo.004391", "title": "The fossil record of the Neogene Carnivore Mammals from Spain", "abstract": "Carnivore mammals (Carnivora, Mammalia) constitute a significant component of the Spanish Neogene faunas, not so much due to their fossil abundance, which is generally low, but rather because of their high degree of taxonomic diversity. We assessed their evolutionary dynamics from the fossil record of Iberian carnivores using per-taxon rates of origination, extinctions and turnover combined with a recent approach for removing the sampling signal from diversity curves. Our analysis interval covers most of the Neogene and the early Pleistocene (MN 2 to MN 17), spanning from around 21.6 to 1.8 Ma. We identified six carnivore associations by applying factor analysis to our data. The diversification pattern shows four origination episodes: MN4, MN7/8, MN12 and MN14. We also identified four extinction episodes. The first two are coincident with the onset of the MN 4 and MN7/8 faunas. The last two extinction episodes take place during MN9, coinciding with the Mid Vallesian Crisis (MVC), and MN13, co-occurring with the Messinian Salinity Crisis (MSC). Two major turnover pulses are recognised during MN4 and MN14, the turnover rate remaining moderately high between MN6 and MN13. We suggest that the pattern observed might be primarily triggered by the biogeographic and climatic shifts that took place during the Neogene.", "keyphrases": ["mid-vallesian faunal turnover", "major extinction event", "iberian carnivora"]}
{"id": "paleo.004254", "title": "Taxonomy, Phylogeny, and Functional Morphology of the Foraminiferal Genus Involutina", "abstract": "Early Jurassic aragonitic foraminifers are outstandingly well-preserved in the Marmorea crust, a multiphased ferromanganese layer limiting the Schn\u00f6ll and Adnet formations (Adnet, Northern Calcareous Alps, Austria). This remarkable preservation, related to the pervasive impregnation of aragonitic tests prior to their recrystallization, allowed observing unknown diagnostic features of the genus Involutina, which typifies the Suborder Involutinina. Thanks to a detailed examination of the Adnet specimens, this paper clarifies the taxonomy, systematic position, and phylogeny of Involutina. A new diagnosis, structural model, and lineage are introduced for the group. Involutina is the direct descendant of Aulotortus and the two taxa probably showed a parallel evolution. As Aulotortus, Involutina presents a high intraspecific variability and its diversity must be revised downward. Current phylogenetic and taxonomic frames of the Suborder Involutinina are firmly questioned as, contrary to previous schemes, the type-genus possesses more than one lamellar deposit per whorl. In Involutina, the height and distribution of papillae on the test surface is not random and probably related to a biological function. We here propose that the papillose lamellae and tube infoldings that characterize representatives of the genus were rudimentary features for light catching and symbiont positioning, respectively.", "keyphrases": ["phylogeny", "involutina", "foraminifer", "marmorea crust", "adnet"]}
{"id": "10.1111/j.1095-8312.2000.tb00216.x", "title": "Why are there so few evolutionary transitions between aquatic and terrestrial ecosystems", "abstract": "Abstract Insects and flowering plants have rarely invaded the sea. Explanations for this have traditionally centered on the unique shortcomings of these groups in the marine environment. We show, however, that transitions among terrestrial, freshwater, and marine environments are infrequent in all major plant and animal clades except tetrapod vertebrates. In general, well-adapted incumbents are at a competitive advantage over would-be invaders from a physically different habitat. Data on the times and places of transition are consistent with our contention that evolutionary transitions among physically different environments are most likely when incumbents in the recipient environment exist in a regime of low-intensity competition and predation, as in terrestrial communities of the middle Paleozoic or the land biotas of oceanic islands. Freshwater environments, in which inferred intensities of predation are lower than in most marine and terrestrial environments, offer less biotic resistance to invaders than do communities in the sea or on land. Most invaders respond to novel physical circumstances by shutting down their metabolic machinery, and therefore add to their subordinate status as competitors with active incumbents. Only active tetrapods, particularly those with high and endothermically driven rates of metabolism, have successfully overcome this limitation.", "keyphrases": ["evolutionary transition", "freshwater", "major plant", "tetrapod", "land"]}
{"id": "10.1130/B31818.1", "title": "Global perturbation of the marine calcium cycle during the Permian-Triassic transition", "abstract": "A negative shift in the calcium isotopic composition of marine carbonate rocks spanning the end-Permian extinction horizon in South China has been used to argue for an ocean acidification event coincident with mass extinction. This interpretation has proven controversial, both because the excursion has not been demonstrated across multiple, widely separated localities, and because modeling results of coupled carbon and calcium isotope records illustrate that calcium cycle imbalances alone cannot account for the full magnitude of the isotope excursion. Here, we further test potential controls on the Permian-Triassic calcium isotope record by measuring calcium isotope ratios from shallow-marine carbonate successions spanning the Permian-Triassic boundary in Turkey, Italy, and Oman. All measured sections display negative shifts in \u03b444/40Ca of up to 0.6\u2030. Consistency in the direction, magnitude, and timing of the calcium isotope excursion across these widely separated localities implies a primary and global \u03b444/40Ca signature. Based on the results of a coupled box model of the geological carbon and calcium cycles, we interpret the excursion to reflect a series of consequences arising from volcanic CO2 release, including a temporary decrease in seawater \u03b444/40Ca due to short-lived ocean acidification and a more protracted increase in calcium isotope fractionation associated with a shift toward more primary aragonite in the sediment and, potentially, subsequently elevated carbonate saturation states caused by the persistence of elevated CO2 delivery from volcanism. Locally, changing balances between aragonite and calcite production are sufficient to account for the calcium isotope excursions, but this effect alone does not explain the globally observed negative excursion in the \u03b413C values of carbonate sediments and organic matter as well. Only a carbon release event and related geochemical consequences are consistent both with calcium and carbon isotope data. The carbon release scenario can also account for oxygen isotope evidence for dramatic and protracted global warming as well as paleontological evidence for the preferential extinction of marine animals most susceptible to acidification, warming, and anoxia.", "keyphrases": ["calcium cycle", "ocean acidification", "global warming", "anoxia"]}
{"id": "10.1017/pab.2015.11", "title": "Using experimental decay of modern forms to reconstruct the early evolution and morphology of fossil enteropneusts", "abstract": "Abstract. Decay experiments are becoming a more widespread tool in evaluating the fidelity of the fossil record. Character interpretations of fossil specimens stand to benefit from an understanding of how decay can result in changes in morphology and, potentially, total character loss. We performed a decay experiment for the Class Enteropneusta to test the validity of anatomical interpretations of the Burgess Shale enteropneust Spartobranchus tenuis and to determine how the preservation of morphological features compares with the sequence of character decay in extant analogues. We used three species of enteropneust (Saccoglossus pusillus, Harrimania planktophilus, and Balanoglossus occidentalis) representing the two major families of Enteropneusta. Comparisons between decay sequences suggest that morphological characters decay in a consistent and predictable manner within Enteropneusta, and do not support the hypothesis of stemward slippage. The gill bars and nuchal skeleton were the most decay resistant, whereas the gill pores and pre-oral ciliary organ were unequivocally the most decay prone. Decay patterns support the identification of the nuchal skeleton, gill bars, esophageal organ, trunk, and proboscis in Spartobranchus tenuis and corroborate a harrimaniid affinity. Bias due to the taphonomic loss of taxonomically informative characters is unlikely. The morphologically simple harrimaniid body plan can be seen, therefore, to be plesiomorphic within the enteropneusts. Discrepancies between the sequence of decay in a laboratory setting and fossil preservation also exist. These discrepancies are highlighted not to discredit the use of modern decay studies but rather to underline their non-actualistic nature. Paleoenvironmental variables besides decay, such as the timeframe between death and early diagenesis as well as postmortem transport, are discussed relative to decay data. These experiments reinforce the strength of a comprehensive understanding of decay sequences as a benchmark against which to describe fossil taxa and understand the conditions leading to fossilization.", "keyphrases": ["decay", "enteropneust", "gill bar"]}
{"id": "10.1126/science.1196166", "title": "Dietary Change and Evolution of Horses in North America", "abstract": "A survey of horse-teeth wear during the past 55 million years implies that evolutionary pressures were generally low. The evolution of high-crowned molars among horses (Family Equidae) is thought to be an adaptation for abrasive diets associated with the spread of grasslands. The sharpness and relief of the worn cusp apices of teeth (mesowear) are a measure of dietary abrasion. We collected mesowear data for North American Equidae for the past 55.5 million years to test the association of molar height and dietary abrasion. Mesowear trends in horses are reflective of global cooling and associated vegetation changes. There is a strong correlation between mesowear and crown height in horses; however, most horse paleopopulations had highly variable amounts of dietary abrasion, suggesting that selective pressures for crown height may have been weak much of the time. However, instances of higher abrasion were observed in some paleopopulations, suggesting intervals of stronger selection for the evolution of dentitions, including the early Miocene shortly before the first appearance of Equinae, the horse subfamily in which high-crowned dentitions evolved.", "keyphrases": ["horse", "north america", "grassland"]}
{"id": "paleo.004227", "title": "Evidence for a Grooming Claw in a North American Adapiform Primate: Implications for Anthropoid Origins", "abstract": "Among fossil primates, the Eocene adapiforms have been suggested as the closest relatives of living anthropoids (monkeys, apes, and humans). Central to this argument is the form of the second pedal digit. Extant strepsirrhines and tarsiers possess a grooming claw on this digit, while most anthropoids have a nail. While controversial, the possible presence of a nail in certain European adapiforms has been considered evidence for anthropoid affinities. Skeletons preserved well enough to test this idea have been lacking for North American adapiforms. Here, we document and quantitatively analyze, for the first time, a dentally associated skeleton of Notharctus tenebrosus from the early Eocene of Wyoming that preserves the complete bones of digit II in semi-articulation. Utilizing twelve shape variables, we compare the distal phalanges of Notharctus tenebrosus to those of extant primates that bear nails (n\u200a=\u200a21), tegulae (n\u200a=\u200a4), and grooming claws (n\u200a=\u200a10), and those of non-primates that bear claws (n\u200a=\u200a7). Quantitative analyses demonstrate that Notharctus tenebrosus possessed a grooming claw with a surprisingly well-developed apical tuft on its second pedal digit. The presence of a wide apical tuft on the pedal digit II of Notharctus tenebrosus may reflect intermediate morphology between a typical grooming claw and a nail, which is consistent with the recent hypothesis that loss of a grooming claw occurred in a clade containing adapiforms (e.g. Darwinius masillae) and anthropoids. However, a cladistic analysis including newly documented morphologies and thorough representation of characters acknowledged to have states constituting strepsirrhine, haplorhine, and anthropoid synapomorphies groups Notharctus tenebrosus and Darwinius masillae with extant strepsirrhines rather than haplorhines suggesting that the form of pedal digit II reflects substantial homoplasy during the course of early primate evolution.", "keyphrases": ["claw", "primate", "phalanx"]}
{"id": "10.1029/2017JE005478", "title": "A Field Guide to Finding Fossils on Mars", "abstract": "The Martian surface is cold, dry, exposed to biologically harmful radiation and apparently barren today. Nevertheless, there is clear geological evidence for warmer, wetter intervals in the past that could have supported life at or near the surface. This evidence has motivated National Aeronautics and Space Administration and European Space Agency to prioritize the search for any remains or traces of organisms from early Mars in forthcoming missions. Informed by (1) stratigraphic, mineralogical and geochemical data collected by previous and current missions, (2) Earth's fossil record, and (3) experimental studies of organic decay and preservation, we here consider whether, how, and where fossils and isotopic biosignatures could have been preserved in the depositional environments and mineralizing media thought to have been present in habitable settings on early Mars. We conclude that Noachian\u2010Hesperian Fe\u2010bearing clay\u2010rich fluvio\u2010lacustrine siliciclastic deposits, especially where enriched in silica, currently represent the most promising and best understood astropaleontological targets. Siliceous sinters would also be an excellent target, but their presence on Mars awaits confirmation. More work is needed to improve our understanding of fossil preservation in the context of other environments specific to Mars, particularly within evaporative salts and pore/fracture\u2010filling subsurface minerals.", "keyphrases": ["mars", "mission", "environment", "pore"]}
{"id": "paleo.008019", "title": "THE DEMOSPONGE GENUS LEPTOMITUS and A NEW SPECIES FROM THE MIDDLE CAMBRIAN OF SPAIN", "abstract": "Abstract:\u2002 Forty\u2010five specimens of Leptomitus conicus sp. nov. have been collected from the base of the Murero Formation (Caesaraugustan, Middle Cambrian) in the Murero area of Zaragoza, north\u2010east Spain. The new species is a small obconical sponge, which has coarse oxeas forming parallel rods that run the whole length of the specimens in the manner typical of the genus. The biostratigraphy and facies of the levels with Leptomitus conicus have been analysed. Palaeoecological information derived from associated trilobites, brachiopods and ichnofossils shows that L.\u2003conicus lived in a soft substrate of a sublittoral environment of low to low/moderate energy. According to established Cambrian palaeogeographical reconstructions, a tropical distribution is inferred for the genus Leptomitus. Based on body shape, wall structure and stratigraphical distribution, a phylogenetic tree of the various Leptomitus species is proposed, with a central stock of simple cylindrical sponges branching out to other morphs.", "keyphrases": ["middle cambrian", "sponge", "trilobite", "substrate"]}
{"id": "10.1002/2014PA002639", "title": "Observation of the dissolution process of Globigerina bulloides tests (planktic foraminifera) by X\u2010ray microcomputed tomography", "abstract": "We performed a 9 day dissolution experiment with tests of the planktic foraminifer Globigerina bulloides at pH 6.7\u2009\u00b1\u20090.1 in water undersaturated with respect to calcite. The initial stage of the dissolution process, which is not recognizable from the surface structure of the tests, was quantitatively evaluated by X-ray microcomputed tomography (XMCT). XMCT revealed three distinct test structures: early-developed calcite formed during the juvenile stage of G. bulloides, an inner calcite layer, and an outer calcite layer. The test ultrastructure was observed by scanning electron microscopy, and CT number evaluated the density distribution in the test. The early-developed calcite and inner calcite layer had low CT numbers (500\u20131300; low density, porous) and were sensitive to dissolution, whereas the outer calcite layer had high CT numbers (<1300; high density) and resisted dissolution. Both the modes and the frequencies of the CT numbers decreased with progress of dissolution. Changes in the CT number histogram with progress of dissolution were quantified in terms of the percentage of calcite volume accounted for by low-density calcite (%\u2009Low-CT-number calcite). A clear linear relationship (R2\u2009=\u20090.87) between %\u2009Low-CT-number calcite and %\u2009Test weight loss was found. This relationship indicates that the amount of test dissolution can be estimated from the distribution of CT numbers. We propose that XMCT measurements will be useful for quantitatively estimating the amount of carbonate loss from foraminiferal tests by dissolution.", "keyphrases": ["dissolution process", "calcite", "x-ray"]}
{"id": "10.1073/pnas.1208693109", "title": "Paleontological and developmental evidence resolve the homology and dual embryonic origin of a mammalian skull bone, the interparietal", "abstract": "The homologies of mammalian skull elements are now fairly well established, except for the controversial interparietal bone. A previous experimental study reported an intriguing mixed origin of the interparietal: the medial portion being derived from the neural crest cells, whereas the lateral portion from the mesoderm. The evolutionary history of such mixed origin remains unresolved, and contradictory reports on the presence or absence and developmental patterns of the interparietal among mammals have complicated the question of its homology. Here we provide an alternative perspective on the evolutionary identity of the interparietal, based on a comprehensive study across more than 300 extinct and extant taxa, integrating embryological and paleontological data. Although the interparietal has been regarded as being lost in various lineages, our investigation on embryos demonstrates its presence in all extant mammalian \u201corders.\u201d The generally accepted paradigm has regarded the interparietal as consisting of two elements that are homologized to the postparietals of basal amniotes. The tabular bones have been postulated as being lost during the rise of modern mammals. However, our results demonstrate that the interparietal consists not of two but of four elements. We propose that the tabulars of basal amniotes are conserved as the lateral interparietal elements, which quickly fuse to the medial elements at the embryonic stage, and that the postparietals are homologous to the medial elements. Hence, the dual developmental origin of the mammalian interparietal can be explained as the evolutionary consequence of the fusion between the crest-derived \u201cpostparietals\u201d and the mesoderm-derived \u201ctabulars.\u201d", "keyphrases": ["homology", "interparietal", "extant taxa", "postparietal", "tabular"]}
{"id": "10.1017/S1431927612001079", "title": "Three-Dimensional Synchrotron Virtual Paleohistology: A New Insight into the World of Fossil Bone Microstructures", "abstract": "Abstract The recent developments of phase-contrast synchrotron imaging techniques have been of great interest for paleontologists, providing three-dimensional (3D) tomographic images of anatomical structures, thereby leading to new paleobiological insights and the discovery of new species. However, until now, it has not been used on features smaller than 5\u20137 \u03bcm voxel size in fossil bones. Because much information is contained within the 3D histological architecture of bone, including an ontogenetic record, crucial for understanding the paleobiology of fossil species, the application of phase-contrast synchrotron tomography to bone at higher resolutions is potentially of great interest. Here we use this technique to provide new 3D insights into the submicron-scale histology of fossil and recent bones, based on the development of new pink-beam configurations, data acquisition strategies, and improved processing tools. Not only do the scans reveal by nondestructive means all of the major features of the histology at a resolution comparable to that of optical microscopy, they provide 3D information that cannot be obtained by any other method.", "keyphrases": ["architecture", "resolution", "ppc-sr\u00b5ct"]}
{"id": "10.1029/2001TC900022", "title": "Upper Rhine Graben: Role of preexisting structures during rift evolution", "abstract": "The evolution of the Cenozoic Upper Rhine Graben was controlled by a repeatedly changing stress field and the reactivation of a complex set of crustal discontinuities that had come into evidence during Permo\u2010Carboniferous times. A comparison of the spatial and temporal thickness distribution of synrift deposits with preexisting fault patterns permits to infer a sequence of distinct basin subsidence phases that can be related to changes in the ambient stress field. Reactivation of a system of late Palaeozoic fault systems, outlining troughs and highs, controlled the nucleation of initially separated middle and late Eocene basins, the depocenters of which coincided with a preexisting WSW\u2010ENE trend. During Oligocene crustal extension the individual basins coalesced, resulting in the development of the SSW\u2010NNE striking Upper Rhine Graben. During the late Oligocene (Chattian) change in stress field, the Upper Rhine Graben was probably reactivated as a dextral strike\u2010slip system with the central graben segment forming a releasing bend. During the early Miocene (Aquitanian), a major reorientation of the regional stress field is held responsible for the main subsidence phase of the northern parts of the Upper Rhine Graben. This is reflected by a counterclockwise rotation and northeastward shift of the depocenter axis and later by the middle Miocene uplift and erosion of the southern parts of the Upper Rhine Graben. During the Plio\u2010Quaternary, the Upper Rhine Graben was reactivated as a sinistral strike\u2010slip system with the central graben segment forming a restraining bend.", "keyphrases": ["upper rhine graben", "north sea", "mediterranean", "urg"]}
{"id": "10.1080/10635150490423430", "title": "Southern hemisphere biogeography inferred by event-based models: plant versus animal patterns.", "abstract": "The Southern Hemisphere has traditionally been considered as having a fundamentally vicariant history. The common trans-Pacific disjunctions are usually explained by the sequential breakup of the supercontinent Gondwana during the last 165 million years, causing successive division of an ancestral biota. However, recent biogeographic studies, based on molecular estimates and more accurate paleogeographic reconstructions, indicate that dispersal may have been more important than traditionally assumed. We examined the relative roles played by vicariance and dispersal in shaping Southern Hemisphere biotas by analyzing a large data set of 54 animal and 19 plant phylogenies, including marsupials, ratites, and southern beeches (1,393 terminals). Parsimony-based tree fitting in conjunction with permutation tests was used to examine to what extent Southern Hemisphere biogeographic patterns fit the breakup sequence of Gondwana and to identify concordant dispersal patterns. Consistent with other studies, the animal data are congruent with the geological sequence of Gondwana breakup: (Africa(New Zealand(southern South America, Australia))). Trans-Antarctic dispersal (Australia <--> southern South America) is also significantly more frequent than any other dispersal event in animals, which may be explained by the long period of geological contact between Australia and South America via Antarctica. In contrast, the dominant pattern in plants, (southern South America(Australia, New Zealand)), is better explained by dispersal, particularly the prevalence of trans-Tasman dispersal between New Zealand and Australia. Our results also confirm the hybrid origin of the South American biota: there has been surprisingly little biotic exchange between the northern tropical and the southern temperate regions of South America, especially for animals.", "keyphrases": ["disjunction", "breakup", "dispersal", "biogeographic pattern", "southern hemisphere"]}
{"id": "paleo.003341", "title": "Internal conulariid structures unveiled using \u00b5CT", "abstract": "An extensive sample of well-preserved conulariids from the Pennsylvanian of the North American Midcontinent (Texas and Oklahoma, USA) have been studied using X-ray micro-Computed Tomography (\u00b5CT) and have shown structures identified as longitudinal muscle bundles and a potential gastric cavity. These unequivocal structures appear in several specimens coming from different sites. Their preservation varies from a gastric cavity with muscle bundles in some individuals to only longitudinal muscle bundles in others. The muscle bundles fuse apically or medially, normally forming V-shaped pairs, and they extend along the theca/exoskeleton, parallel to the corner, towards the aperture. Longitudinal bundles have predominant perradial positions. Although there have been some articles on conulariid soft parts, most of them refer to relic soft parts. This is the first time that these structures are shown using \u00b5CT. Discovery of conulariid soft parts contributes to knowledge of metazoan evolutionary history.", "keyphrases": ["conulariid", "cavity", "corner", "longitudinal bundle", "soft part"]}
{"id": "10.1017/pab.2017.37", "title": "Land to sea transitions in vertebrates: the dynamics of colonization", "abstract": "Abstract. \n Vertebrates with terrestrial or freshwater ancestors colonized the sea from the Early Triassic onward and became competitively dominant members of many marine ecosystems throughout the Mesozoic and Cenozoic eras. The circumstances that led to initial marine colonization have, however, received little attention. One hypothesis is that mass extinction associated with ecosystem collapse provided opportunities for clades of amphibians, reptiles, birds, and mammals to enter marine environments. Another is that competitive pressures in donor ecosystems on land and in freshwater, coupled with abundant food in nearshore marine habitats, favored marine colonization. Here we test these hypotheses by compiling all known secondarily marine amniote clades and their times of colonization. Marine amniotes are defined as animals whose diet consists primarily of marine organisms and whose locomotion includes swimming, diving, or wading in salt water. We compared the number of clades entering during recovery phases from mass extinctions with the rate of entry of clades during nonrecovery intervals of the Mesozoic and Cenozoic. We conservatively identify 69 marine colonizations by amniotes. The only recovery interval for which prior mass extinction could have been a trigger for marine entry is the Early Triassic, when four clades colonized the sea over 7 Myr, significantly above the rates at which clades entered during other intervals. High nearshore productivity was a greater enticement to colonization than was a low diversity of potential marine competitors or predators in nearshore environments of a highly competitive terrestrial or freshwater donor biota. Rates of marine entry increased during the Cenozoic, in part because of rising productivity and in part thanks to the participation of warm-blooded birds and mammals, which broadened the range of thermal environments in which initial colonization of the sea became possible.", "keyphrases": ["early triassic", "marine ecosystem", "predator", "land"]}
{"id": "10.1098/rstb.1978.0019", "title": "Fossil Giraffes from the Miocene of Africa and a Revision of the Phylogeny of the Giraffoidea", "abstract": "Specimens of Climacoceras africanus are described from Maboko, Kenya. The new species Climacoceras gentryi is established on the basis of ossicones, mandibles, and upper and lower dentitions from Fort Ternan and Baringo, Kenya. By interpretation of its lower canines Climacoceras is identified as a giraffoid and is placed in the new family Climacoceridae. Canthumeryx sirtensis is identified from Muruarot and Rusinga, Kenya. A dentition and associated partial skeleton of this species are described. The teeth agree closely with specimens of the same species from Gebel Zelten, Libya. Zarafa zelteni from Gebel Zelten is synonymized with Canthumeryx sirtensis. Again on the basis of its lower canines Canthumeryx is identified as a giraffoid and is placed in the new family Canthumerycidae. Specimens of Palaeotragus primaevus are described from Baringo, Kenya. This material includes a cranium with the ossicones, skull roof, occipital and basicranial regions preserved. Palaeotragus primaevus specimens from Fort Ternan are used in this description and some of these are redescribed. The relations of the giraffoids are assessed by methods of phylogenetic systematics. Palaeomeryx, Prolibytherium and Propalaeoryx are excluded from the Giraffoidea as their lower canines are not known. The Palaeotraginae is shown to be an invalid polyphyletic grouping and the genus Palaeotragus is also shown to be polyphyletic. Palaeotragus microdon is probably synonymous with Palaeotragus rouenii and the three species Palaeotragus rouenii (P. microdon), Palaeotragus coelophrys and Palaeotragus quadricornis are retained in the genus Palaeotragus. It is suggested that 'Palaeotragus' expectans and 'Palaeotragus' decipiens are closely related to Samotherium. Palaeotragus primaevus is probably synonymous with Palaeotragus tungurensis and this species is closely related to the giraffines. With slight changes the subfamilies Sivatheriinae and Giraffinae are valid monophyletic groups. Hydaspitherium is synonymized with Bramatherium and the Sivatheriinae includes the genera Giraffokeryx, Birgerbohlinia, Bramatherium and Sivatherium while the Giraffinae includes the genera Honanotherium, Bohlinia and Giraffa and the species 'Palaeotragus' tungurensis (P. primaevus). Okapia is identified as the sister-group of the other giraffids. Triceromeryx is the sister-group of the Giraffidae. Canthumeryx is the sister-group of Triceromeryx plus the Giraffidae while Climacoceras is the sister-group of the other giraffoids.", "keyphrases": ["giraffoidea", "ossicone", "giraffid"]}
{"id": "paleo.005581", "title": "An Australian multituberculate and its palaeobiogeographic implications", "abstract": "A dentary fragment containing a tiny left plagiaulacoid fourth lower premolar from the Early Cretaceous (Aptian) of Victoria provides the first evidence of the Multituberculata from Australia. This unique specimen represents a new genus and species, Corriebaatar marywaltersae, and is placed in a new family, Corriebaataridae. The Australian fossil, together with meagre records of multituberculates from South America, Africa, and Madagascar, reinforces the view that Multituberculata had a cosmopolitan distribution during the Mesozoic, with dispersal into eastern Gondwana probably occurring prior to enforcement of climatic barriers (indicated by marked differentiation in regional floras) in the Early Cretaceous.", "keyphrases": ["multituberculate", "early cretaceous", "corriebaatar marywaltersae", "madagascar", "gondwana"]}
{"id": "paleo.003206", "title": "A Relict Stem Salamander: Evidence from the Early Cretaceous of Siberia", "abstract": "The early evolution of salamanders, which are one of the three living groups of lissamphibians, is not well known. Both stem- and crown-group salamanders first appeared in the Middle Jurassic (Bathonian), but subsequently had different evolutionary histories: stem salamanders were thought to have gone extinct in the Late Jurassic, while crown salamanders persist to the present day. Here, I report the discovery of an indeterminate stem salamander in the Lower Cretaceous (Aptian\u2014Albian) Ilek Formation of Western Siberia. This is new evidence that the most basal salamanders survived beyond the Jurassic\u2014Cretaceous boundary and co-existed with crown-group salamanders during approximately the first 40 million years of the known history of salamanders. The recognition of stem salamanders in the Early Cretaceous of Western Siberia adds to the inventory of taxa that suggest this area was a refugium for various groups of vertebrates with Jurassic affinities.", "keyphrases": ["salamander", "early cretaceous", "bathonian"]}
{"id": "paleo.000374", "title": "ULTRASTRUCTURAL AND FUNCTIONAL MORPHOLOGY OF EGGSHELLS SUPPORTS THE IDEA THAT DINOSAUR EGGS WERE INCUBATED BURIED IN A SUBSTRATE", "abstract": "Abstract:\u2002 The reproductive biology of dinosaurs is of great interest, particularly in light of the many fossil eggs assigned to this group. The ultrastructural characteristics of dinosaur eggshells are examined in order to calculate water vapour conductance, which indicates the nesting environment. Data were mainly derived from the literature but new values are also presented. Allometric analyses were carried out on a variety of shell parameters against predicted egg mass, and comparison was made with allometric equations for bird eggs. Shell thickness was generally larger than seen for extant birds. Total pore number and pores per unit area were similar to values predicted from bird eggs. Total pore area showed an isometric increase with egg mass, parallel to the relationship for birds, but the constant value was an order to magnitude higher than the bird values. Pore radius was unaffected by egg mass. Water vapour conductance showed an allometric increase with egg mass, parallel to the bird values, but for any given egg mass values for dinosaurs were an order of magnitude higher. Mass\u2010specific water vapour conductance was unaffected by egg mass but was an order of magnitude higher than the bird values. Water vapour conductance per pore showed an allometric decrease with egg mass but again the predicted values were an order of magnitude higher than for bird eggs. The ultrastructural characteristics of dinosaur eggshells indicate that the nesting environment had to be saturated with water vapour and that dinosaur eggs had to be fully buried in a substrate. In this sense, therefore, dinosaur eggs resemble more those of modern reptiles than those of birds. As a consequence, maintenance of incubation conditions would have depended on the prevailing environment.", "keyphrases": ["egg", "substrate", "nesting environment", "extant bird"]}
{"id": "10.1002/spp2.1016", "title": "The cranial endocast of the Middle Devonian dipnoan Dipterus valenciennesi and a fossilized dipnoan otoconial mass", "abstract": "The well known Middle Devonian (Eifelian\u2013Givetian) lungfish Dipterus valenciennesi from Scotland, UK, has been studied for more than one hundred years though our understanding of the neurocranium and cranial cavity is incomplete. Micro\u2010CT scanning demonstrates that the internal cast of the cranial cavity, the endocast, possesses a mix of primitive and derived characters. The olfactory bulbs are sessile, as in the derived extant Lepidosirenidae. However, Dipterus valenciennesi possesses the primitive condition of a shallow telencephalon unlike Upper Devonian forms such as Rhinodipterus kimberleyensis and extant lungfish taxa. Further information revealed by micro\u2010CT scanning has allowed coding for characters pertaining to the neurocranial cristae, previously unobservable in Dipterus valenciennesi, allowing hypotheses of relationships between Devonian Dipnoi and the position of Dipterus valenciennesi to be reassessed. New analyses do not refine the phylogenetic position of Dipterus valenciennesi but do increase support for most recently established Devonian dipnoan phylogeny. The first record of a three\u2010dimensionally preserved fossilized otoconial mass from the utricular recess in a fossil dipnoan is also described. Comparison of morphometric data of the endosseous and soft tissue manifestations of the labyrinth system in extant dipnoan taxa demonstrates that there is largely good correspondence between the two. When compared to Dipterus valenciennesi, extant taxa exhibit semi\u2010circular canals that are reduced in length. Furthermore, compared to Dipterus, in extant dipnoan taxa the size of the otoconial mass has increased relative to the utricular and sacculolagenar pouches containing them. The functional implications for these observations suggest that the Dipnoi have evolved towards a more sedentary lifestyle and behaviour at least since the Middle Devonian.", "keyphrases": ["middle devonian", "dipterus", "otoconial mass", "rhinodipterus kimberleyensis"]}
{"id": "10.26879/557", "title": "Using X-ray computed tomography analysis tools to compare the skeletal element morphology of fossil and modern frog (Anura) species", "abstract": "Computed tomography (CT) analysis software has predominantly been developed for medical and industrial use. Thus far there have not been detailed reports in the palaeontological literature of CT analysis tools utilizing automatic analysis functions for visual 3D comparisons between different taxa/species in order to assess and quantify differences. This paper presents the methodology for the general morphological comparison and analysis of fossil and modern bones\u2013in this case frog femora are showcased. Industrial X-ray computed tomography analysis functions are applied to the analysis, and specifically, the comparison, of bone morphologies and micro-anatomical differences (e.g., cortical wall thickness) of differentially sized frog taxa. In contrast to traditional landmark analysis, this method makes use of the higher detail of the full surface data in the form of a CAD (Computer-aided drafting) data set output from the microCT scan. The application of these industrial analysis functions is shown to be useful for viewing of qualitative, as well as quantitative, differences. Differences are highlighted using 3D nominal/actual comparisons, and wall thickness is compared using the wall thickness analysis function applied to both samples side by side. Single bones as well as complete frog specimens were scanned and, in the case of the latter, femora were virtually extracted (segmented) for the purposes of comparison with other specimens. These techniques may be used for the effective identification and quantification of morphological differences between fossil and extant taxa. Thalassa Matthews. Iziko South African Museum, 25 Queen Victoria Street, Cape Town 8000, South Africa and DST-NRF Centre of Excellence in Palaeosciences, Evolutionary Studies Institute, University of the Witwatersrand, Private Bag 3, Wits, 2050, South Africa. tmatthews.matthews@gmail.com Anton du Plessis. CT Scanner Facility, Central Analytical Facilities, Paul Sauer Building, Bosman Street, University of Stellenbosch, Stellenbosch, 7602, South Africa/Physics Department, University of Stellenbosch, Stellenbosch, 7602, South Africa. anton2@sun.ac.za", "keyphrases": ["x-ray", "whole anatomy", "lissamphibian", "new technology"]}
{"id": "10.1111/1475-4983.00309", "title": "Functional Morphology of Stylophoran Echinoderms", "abstract": "The life orientation and mode of life of stylophorans are a subject of much ongoing debate. Examination of the ornamentation occurring both on the arm and theca in several cornutes and mitrates strongly supports the view that the life orientation was similar in all stylophorans and was \u2018flat\u2010surface down\u2019. The presence of an asymmetrical ornamentation adapted to hinder, or minimize, back slippage of the organism in all stylophorans gives strong support to their interpretation as mostly sessile organisms, feeding with the arm facing the current and the theca downstream. The examination of a wide array of thecal morphologies and sculpture patterns displayed by the various groups of cornutes and mitrates allows the identification of three main modes of life in stylophorans: (1) an epibenthic mode of life, with the theca as main anchor to the substrate (e.g. asymmetrical cornutes, Diamphidiocystis); (2) an epibenthic mode of life, with the arm as main anchor to the sediment (e.g. symmetrical cornutes, Peltocystis, primitive Mitrocystitida, some Kirkocystidae); (3) an infaunal mode of life, with the theca buried in a slightly inclined attitude (e.g. some Kirkocystidae, Mitrocystitida with cuesta\u2010shaped ribs). The partially buried mode of life of Lagynocystis is intermediate between 2 and 3.", "keyphrases": ["morphology", "stylophorans", "cornute", "mitrate"]}
{"id": "paleo.002273", "title": "Oldest Known Pantherine Skull and Evolution of the Tiger", "abstract": "The tiger is one of the most iconic extant animals, and its origin and evolution have been intensely debated. Fossils attributable to extant pantherine species-lineages are less than 2 MYA and the earliest tiger fossils are from the Calabrian, Lower Pleistocene. Molecular studies predict a much younger age for the divergence of modern tiger subspecies at <100 KYA, although their cranial morphology is readily distinguishable, indicating that early Pleistocene tigers would likely have differed markedly anatomically from extant tigers. Such inferences are hampered by the fact that well-known fossil tiger material is middle to late Pleistocene in age. Here we describe a new species of pantherine cat from Longdan, Gansu Province, China, Panthera zdanskyi sp. nov. With an estimated age of 2.55\u20132.16 MYA it represents the oldest complete skull of a pantherine cat hitherto found. Although smaller, it appears morphologically to be surprisingly similar to modern tigers considering its age. Morphological, morphometric, and cladistic analyses are congruent in confirming its very close affinity to the tiger, and it may be regarded as the most primitive species of the tiger lineage, demonstrating the first unequivocal presence of a modern pantherine species-lineage in the basal stage of the Pleistocene (Gelasian; traditionally considered to be Late Pliocene). This find supports a north-central Chinese origin of the tiger lineage, and demonstrates that various parts of the cranium, mandible, and dentition evolved at different rates. An increase in size and a reduction in the relative size of parts of the dentition appear to have been prominent features of tiger evolution, whereas the distinctive cranial morphology of modern tigers was established very early in their evolutionary history. The evolutionary trend of increasing size in the tiger lineage is likely coupled to the evolution of its primary prey species.", "keyphrases": ["tiger", "gansu province", "china"]}
{"id": "10.1080/02724634.2019.1645147", "title": "A New Crurotarsan Archosaur From the Late Triassic of South Wales", "abstract": "ABSTRACT We report a third archosaur from the Late Triassic cavity-fill sediments of Pant-y-ffynnon Quarry in South Wales, in addition to the basal crocodylomorph Terrestrisuchus and the basal sauropodomorph dinosaur Pantydraco. The new taxon, Aenigmaspina pantyffynnonensis, previously referred to informally as \u2018Edgar,\u2019 was recovered in 1952 and is preserved as a tight cluster of vertebrae, ribs, and a scapula in a single block, as well as numerous associated, but now isolated, elements, including skull bones, vertebrae, further putative elements of the forelimb, and a partial pelvis. We present a digital model based on computed tomography (CT) scans of the main associated blocks, which shows exquisite detail of an associated series of 12 cervical and anterior dorsal vertebrae, with ribs and a scapula. The well-developed spine tables and eight matching osteoderms confirm that this is a crurotarsan archosaur, but it lacks apomorphies of all major crurotarsan clades. Phylogenetic analysis gives equivocal results, showing weak relationships with Proterochampsidae and Ornithosuchidae; the new taxon might lie close to Erpetosuchidae, based on the \u2018Y'-shaped spine tables.", "keyphrases": ["archosaur", "south wales", "aenigmaspina pantyffynnonensis", "skull bone"]}
{"id": "10.1073/pnas.0910513107", "title": "Global patterns in leaf 13C discrimination and implications for studies of past and future climate", "abstract": "Fractionation of carbon isotopes by plants during CO2 uptake and fixation (\u0394leaf) varies with environmental conditions, but quantitative patterns of \u0394leaf across environmental gradients at the global scale are lacking. This impedes interpretation of variability in ancient terrestrial organic matter, which encodes climatic and ecological signals. To address this problem, we converted 3,310 published leaf \u03b413C values into mean \u0394leaf values for 334 woody plant species at 105 locations (yielding 570 species-site combinations) representing a wide range of environmental conditions. Our analyses reveal a strong positive correlation between \u0394leaf and mean annual precipitation (MAP; R2 = 0.55), mirroring global trends in gross primary production and indicating stomatal constraints on leaf gas-exchange, mediated by water supply, are the dominant control of \u0394leaf at large spatial scales. Independent of MAP, we show a lesser, negative effect of altitude on \u0394leaf and minor effects of temperature and latitude. After accounting for these factors, mean \u0394leaf of evergreen gymnosperms is lower (by 1\u20132.7\u2030) than for other woody plant functional types (PFT), likely due to greater leaf-level water-use efficiency. Together, environmental and PFT effects contribute to differences in mean \u0394leaf of up to 6\u2030 between biomes. Coupling geologic indicators of ancient precipitation and PFT (or biome) with modern \u0394leaf patterns has potential to yield more robust reconstructions of atmospheric \u03b413C values, leading to better constraints on past greenhouse-gas perturbations. Accordingly, we estimate a 4.6\u2030 decline in the \u03b413C of atmospheric CO2 at the onset of the Paleocene-Eocene Thermal Maximum, an abrupt global warming event \u223c55.8 Ma.", "keyphrases": ["leaf", "annual precipitation", "altitude", "functional type"]}
{"id": "paleo.001011", "title": "Postcranial material of Nothosaurus marchicus from the Lower Muschelkalk (Anisian) of Winterswijk, The Netherlands, with remarks on swimming styles and taphonomy", "abstract": "The postcranial morphology of Nothosaurus from Winterswijk is described on the basis of three partially preserved skeletons. Because of the association with a diagnostic cranium, two of these can be confidently assigned to N. marchicus. Preserved humeri are recognized as morphotype II, which confirms the relationship between this humeral morphotype and N. marchicus. The occurrence of an additional nothosaur taxon in the Lower Muschelkalk, strong sexual dimorphism, or a broader size range of N. marchicus is evidenced again. The postcranial morphology of Nothosaurus is compared to published and new data on the basal pistosauroid (cf. Cymatosaurus) from the same locality. Numerous shared morphological characters of N. marchicus, Nothosaurus sp., and the basal pistosauroid from Winterswijk hamper assignment of isolated bones, which is presently only possible if a combination of features on multiple bones from a single individual can be assessed. Ontogenetic stage of the described skeletons is discussed as well. Differences between N. marchicus, the basal pistosauroid, and the morphologically similar, but smaller pachypleurosaur A. heterodontus are mainly related to the morphologies of the humerus, ulna, and the clavicle-interclavicle complex, and thereby indicate different modes of locomotion i.e., swimming styles. The pachypleurosaur and the basal pistosauroid were most likely anguilliform swimmers, whereas Nothosaurus also employed its forelimbs during swimming (paraxial swimming). Taphonomical observations on material of the Winterswijk locality indicate the presence of scavengers, although most disarticulated skeletons were transported by water and decayed and disintegrated in shallow water.\nWe dedicate this paper to Wim Berkelder, Winterswijk, The Netherlands a passionate private collector of Winterswijk fossils.", "keyphrases": ["swimming style", "taphonomy", "sexual dimorphism", "winterswijk fossil", "skull"]}
{"id": "10.1017/S0094837300005121", "title": "Adaptive radiation of the comatulid crinoids", "abstract": "Modern crinoids are dominated by the comatulids (unstalked forms) which range from the intertidal to abyssal depths. Modern stalked crinoids are restricted to depths greater than about 100 m. In the geologic past some stalked crinoids lived at depths of a few tens of meters or less in reef and bank environments. The primary vehicles postulated for the post-Triassic radiation of comatulids are lack of permanent fixation to the substratum and the capacity for mobility. Development of complex muscular articulations has enabled crawling or swimming which serve in habitat selection and avoidance of stress and predators. These and other adaptations may have bestowed on comatulids a higher survival capacity in shallow-water environments compared to stalked crinoids. Modern stalked crinoids lack mobility and complex behavioral adaptations seen in comatulids. Possibly, stalked crinoids in shallow water were unable to cope with the radiation of abundant, predaceous bony fishes in the late Mesozoic and became restricted to greater depths while the more adaptable comatulids gained ascendancy in shallow water.", "keyphrases": ["comatulid", "crinoid", "mobility", "swimming"]}
{"id": "10.7306/gq.1282", "title": "Calcareous nannoplankton in the Upper Jurassic marine deposits of the Bohemian Massif: new data concerning the Boreal\u2013Tethyan communication corridor", "abstract": "Calcareous nannoplankton assemblages from the Jurassic relict deposits in the northern part of the Bohemian Massif are described here for the first time. They are generally of low diversity and dominated by watznaueriaceans. Some of them are diagenetically affected, probably due to dolomitisation. Calcareous nannoplankton enables the stratigraphical range of the Northern Bohemia Jurassic succession to be extended to the Tithonian by reference to the stratigraphical range of Jurassic platform sequences in Central Poland and the eastern part of the Bohemian Massif. The Oxfordian\u2013Kimmeridgian nannofossil assemblages indicate a generally oligotrophic condition of the restricted sea with episodic fluvial input containing terrestrial nutrients. The character of the upper part of the water column was generally uniform and did not reflect variability at the sea-floor expressed by lithofacies diversity. The palaeoenvironment interpreted for the famous former palaeontological locality \u201cSternberk Quarry\u201d was characterized by a higher nutrient content and more stable environment. The Tithonian nannofossil assemblages contain warm-water Tethyan taxa which suggest south-north migration of nannoplankton due to warming during the Jurassic\u2013Cretaceous boundary interval.", "keyphrases": ["bohemian massif", "permo-carboniferous deposit", "tithonian stage", "calcareous nannofossil"]}
{"id": "10.2307/3514834", "title": "Taphonomy of three dinosaur bone beds in the Upper Cretaceous Two Medicine Formation of northwestern Montana; evidence for drought-related mortality", "abstract": "Two bone beds, Canyon Bone Bed and Dino Ridge Quarry, have yielded the near-exclusive remains of a new species of Styracosaurus (Family Ceratopsidae); the third bone bed, Westside Quarry, is dominated by a new species of Prosaurolophus (Family Hadrosauridae). Evidence supporting a drought hypothesis includes: 1) a seasonal, semiarid paleoclimate, 2) associated caliche horizons, 3) aqueous depositional settings, 4) apparent age distributions characteristic of modern drought mortality (CBB and DRQ), and 5) the intraformational recurrence of low-diversity bone beds. Several alternative scenarios were considered, but drought proved most reasonable in light of the enhanced probability of preserving drought assemblages, and the species-selective and recurrent nature of modern drought mortality", "keyphrases": ["mortality", "drought", "depositional setting"]}
{"id": "paleo.005517", "title": "Osteology of the sauropod embryos from the Upper Cretaceous of Patagonia", "abstract": "Exceptionally well-preserved embryonic skulls of Upper Cretaceous (Campanian Anacleto Formation) sauropods from Auca Mahuevo (Neuqu\u00e9n Province, Argentina) provide important insights into the ontogeny and evolution of titanosaurian neosauropods. The most important cranial modifications occurring during titanosaurian ontogeny appear to be centered on the infraorbital and narial regions, which exhibit a substantial degree of \"mosaic\" evolution. On one hand, the Auca Mahuevo embryos show a large jugal that forms part of the lower margin of the skull and unretracted external nares, as indicated by the position and orientation of the lacrimals as well as the anterior extension of the frontals. Both of these features are ancestral for neosauropods, being present in prosauropods. On the other hand, the embryonic skull exhibits a large ventral notch, tentatively interpreted as homologous to the neosauropod preantorbital fenestra, that opens ventral to the jugal and between the maxilla and the quadratojugal, and a temporal region that closely resembles the adult neosauropod condition. This mosaic of character states indicates that different regions of the skull of titanosaurian neosauropods acquired their characteristic morphology at substantially different rates during their ontogenetic development.", "keyphrases": ["patagonia", "skull", "campanian anacleto formation"]}
{"id": "10.1371/journal.pone.0194708", "title": "Chronological reassessment of the Middle to Upper Paleolithic transition and Early Upper Paleolithic cultures in Cantabrian Spain", "abstract": "Methodological advances in dating the Middle to Upper Paleolithic transition provide a better understanding of the replacement of local Neanderthal populations by Anatomically Modern Humans. Today we know that this replacement was not a single, pan-European event, but rather it took place at different times in different regions. Thus, local conditions could have played a role. Iberia represents a significant macro-region to study this process. Northern Atlantic Spain contains evidence of both Mousterian and Early Upper Paleolithic occupations, although most of them are not properly dated, thus hindering the chances of an adequate interpretation. Here we present 46 new radiocarbon dates conducted using ultrafiltration pre-treatment method of anthropogenically manipulated bones from 13 sites in the Cantabrian region containing Mousterian, Aurignacian and Gravettian levels, of which 30 are considered relevant. These dates, alongside previously reported ones, were integrated into a Bayesian age model to reconstruct an absolute timescale for the transitional period. According to it, the Mousterian disappeared in the region by 47.9\u201345.1ka cal BP, while the Ch\u00e2telperronian lasted between 42.6k and 41.5ka cal BP. The Mousterian and Ch\u00e2telperronian did not overlap, indicating that the latter might be either intrusive or an offshoot of the Mousterian. The new chronology also suggests that the Aurignacian appears between 43.3\u201340.5ka cal BP overlapping with the Ch\u00e2telperronian, and ended around 34.6\u201333.1ka cal BP, after the Gravettian had already been established in the region. This evidence indicates that Neanderthals and AMH co-existed <1,000 years, with the caveat that no diagnostic human remains have been found with the latest Mousterian, Ch\u00e2telperronian or earliest Aurignacian in Cantabrian Spain.", "keyphrases": ["cantabrian spain", "aurignacian", "ch\u00e2telperronian"]}
{"id": "paleo.001267", "title": "Nest substrate reflects incubation style in extant archosaurs with implications for dinosaur nesting habits", "abstract": "Dinosaurs thrived and reproduced in various regions worldwide, including the Arctic. In order to understand their nesting in diverse or extreme environments, the relationships between nests, nesting environments, and incubation methods in extant archosaurs were investigated. Statistical analyses reveal that species of extant covered nesters (i.e., crocodylians and megapodes) preferentially select specific sediments/substrates as a function of their nesting style and incubation heat sources. Relationships between dinosaur eggs and the sediments in which they occur reveal that hadrosaurs and some sauropods (i.e., megaloolithid eggs) built organic-rich mound nests that relied on microbial decay for incubation, whereas other sauropods (i.e., faveoloolithid eggs) built sandy in-filled hole nests that relied on solar or potentially geothermal heat for incubation. Paleogeographic distribution of mound nests and sandy in-filled hole nests in dinosaurs reveals these nest types produced sufficient incubation heat to be successful up to mid latitudes (\u226447\u00b0), 10\u00b0 higher than covered nesters today. However, only mound nesting and likely brooding could have produced sufficient incubation heat for nesting above the polar circle (>66\u00b0). As a result, differences in nesting styles may have placed restrictions on the reproduction of dinosaurs and their dispersal at high latitudes.", "keyphrases": ["incubation", "extant archosaur", "sauropod", "nest"]}
{"id": "10.1146/annurev-earth-040610-133525", "title": "Using Time-of-Flight Secondary Ion Mass Spectrometry to Study Biomarkers", "abstract": "Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a technique designed to analyze the composition and spatial distribution of molecules and chemical structures on surfaces. These capabilities have generated much interest in its use in geobiology, in particular for the characterization of organic biomarkers (molecular biosignatures) at the microscopic level. We here discuss the strengths, weaknesses, and potential of ToF-SIMS for biomarker analyses with a focus on applications in geobiology, including biogeochemistry, organic geochemistry, geomicrobiology, and paleobiology. After describing the analytical principles of ToF-SIMS, we discuss issues of biomarker spectral formation and interpretation. Then, key applications of ToF-SIMS to soft (microbial matter, cells), hard (microbial mineral precipitates), and liquid (petroleum) samples relevant in geobiology are reviewed. Finally, we examine the potential of ToF-SIMS in biomarker research and the current limitations and obstacles for which furthe...", "keyphrases": ["ion mass spectrometry", "tof-sims", "application"]}
{"id": "10.1017/jpa.2016.59", "title": "A new damsel-dragonfly from the Lower Jurassic of northwestern China and its paleobiogeographic significance", "abstract": "Abstract. \n A new species of the Lower Jurassic genus Dorsettia Whalley, 1985 is described from the Lower Jurassic Badaowan Formation of the Junggar Basin, northwestern China, as Dorsettia sinica new species. It provides additional morphological characters for this genus and is the earliest Jurassic dragonfly in China after the end-Triassic extinction. The occurrence of Dorsettia in England and northwestern China indicates that the end-Triassic extinction probably did not have a drastic influence on damsel-dragonflies, or that the dispersal of damsel-dragonflies was relatively quick during the earliest Jurassic.", "keyphrases": ["damsel-dragonflie", "northwestern china", "end-triassic extinction", "dispersal"]}
{"id": "paleo.009033", "title": "A New Notosuchian from the Late Cretaceous of Brazil and the Phylogeny of Advanced Notosuchians", "abstract": "A new notosuchian crocodyliform from the Late Cretaceous Bauru Group found in the southeastern State of S\u00e3o Paulo (Brazil) is described here. The new taxon, Caipirasuchus stenognathus, is referred as a new species of the recently erected genus Caipirasuchus within the clade Sphagesauridae based on a phylogenetic analysis of basal mesoeucrocodylians. Caipirasuchus stenognathus is represented by an almost complete skull and lower jaw that has autapomorphic characters that distinguish it from other species of Sphagesauridae. These autapomorphies include: maxilla forming part of the orbital margin (absence of lacrimal-jugal contact), nasal with smooth depressions on the posterior region close to the contact with the maxilla and lacrimal, postorbital with posterior palpebral facet that extends posteriorly underneath the ear-flap groove, and a distinct anterior process of the medial flange of the retroarticular process. Additionally, the new taxon lacks autapomorphic features described in other sphagesaurids. The phylogenetic analysis results in a monophyletic genus Caipirasuchus, that is the sister group of a clade fomed by Sphagesaurus huenei, Caryonosuchus pricei, and Armadillosuchus arrudai. Sphagesaurids also include a basal clade formed by Adamantinasuchus navae and Yacarerani boliviensis. Other notosuchian taxa, such as Mariliasuchus amarali, Labidiosuchus amicum, Notosuchus terrestris, and Morrinhosuchus luziae are successive sister taxa of Sphagesauridae, forming a clade of advanced notosuchians that are restricted to the Late Cretaceous of South America. These results contrast with most previous phylogenetic hypotheses of the group that depicted some members of Sphagesauridae as more closely related to baurusuchids, or found Asian (e.g., Chimaerasuchus) or African (Malawisuchus, Pakasuchus) forms nested within advanced notosuchians that are, according to our analysis, endemic of the Late Cretaceous of South America.", "keyphrases": ["late cretaceous", "brazil", "sphagesaurid", "south america", "baurusuchid"]}
{"id": "paleo.002283", "title": "METHODOLOGIES FOR THE VISUALIZATION AND RECONSTRUCTION OF THREE-DIMENSIONAL FOSSILS FROM THE SILURIAN HEREFORDSHIRE LAGERST\u00c4TTE", "abstract": "The dominantly soft-bodied fauna of the Silurian (Wenlock) Herefordshire Lagerst\u00e4tte of England is preserved as three-dimensional calcitic fossils within calcareous nodules. These fossils are difficult to interpret from study of sections produced by splitting, and are difficult also to isolate from their matrix. CT scanning of nodules is feasible, but is expensive and unlikely to be able to image the fossils at a sufficiently high resolution. We describe a technique based on serial grinding and digital photography which enables the capture of three-dimensional morphological information from the fossils. Computer video files are used to package the resulting datasets for inspection . Three-dimensional reconstructions can be created by a method involving the manual tracing of outlines on each image, but we consider this approach inappropriate in this instance. Datasets from grinding are treated instead as volumes, which are rendered either directly to produce virtual X-ray images, or by the computation of isosurfaces which are then visualized by ray-tracing. Rendering is performed from sequential angles to produce video files of rotating three-dimensional models. The method is illustrated with reconstructions of a trilobite and graptolite associated with the Herefordshire soft-bodied fauna, and of the worm-like mollusc Acaenoplax hayae. Reconstructions produced in this way can be retouched easily and manipulated to remove noise and preservational artifacts, to dissect out structures for detailed study, or to combine part and counterpart into a single reconstruction. The approach will provide the primary means of study of the Herefordshire fauna, and has the potential to provide a method of obtaining and/or communicating morphological information in a variety of palaeontological applications.", "keyphrases": ["image", "serial grinding", "graptolite", "virtual fossil", "spiers software suite"]}
{"id": "paleo.003129", "title": "Reptile-like physiology in Early Jurassic stem-mammals", "abstract": "Despite considerable advances in knowledge of the anatomy, ecology and evolution of early mammals, far less is known about their physiology. Evidence is contradictory concerning the timing and fossil groups in which mammalian endothermy arose. To determine the state of metabolic evolution in two of the earliest stem-mammals, the Early Jurassic Morganucodon and Kuehneotherium, we use separate proxies for basal and maximum metabolic rate. Here we report, using synchrotron X-ray tomographic imaging of incremental tooth cementum, that they had maximum lifespans considerably longer than comparably sized living mammals, but similar to those of reptiles, and so they likely had reptilian-level basal metabolic rates. Measurements of femoral nutrient foramina show Morganucodon had blood flow rates intermediate between living mammals and reptiles, suggesting maximum metabolic rates increased evolutionarily before basal metabolic rates. Stem mammals lacked the elevated endothermic metabolism of living mammals, highlighting the mosaic nature of mammalian physiological evolution.", "keyphrases": ["physiology", "incremental tooth cementum", "blood flow rate"]}
{"id": "paleo.010527", "title": "Exceptionally Preserved Cambrian Trilobite Digestive System Revealed in 3D by Synchrotron-Radiation X-Ray Tomographic Microscopy", "abstract": "The Cambrian \u2018Orsten\u2019 fauna comprises exceptionally preserved and phosphatised microscopic arthropods. The external morphology of these fossils is well known, but their internal soft-tissue anatomy has remained virtually unknown. Here, we report the first non-biomineralised tissues from a juvenile polymerid trilobite, represented by digestive structures, glands, and connective strands harboured in a hypostome from the Swedish \u2018Orsten\u2019 fauna. Synchrotron-radiation X-ray tomographic microscopy enabled three-dimensional internal recordings at sub-micrometre resolution. The specimen provides the first unambiguous evidence for a J-shaped anterior gut and the presence of a crop with a constricted alimentary tract in the Trilobita. Moreover, the gut is Y-shaped in cross section, probably due to a collapsed lumen of that shape, another feature which has not previously been observed in trilobites. The combination of anatomical features suggests that the trilobite hypostome is functionally analogous to the labrum of euarthropods and that it was a sophisticated element closely integrated with the digestive system. This study also briefly addresses the preservational bias of the \u2018Orsten\u2019 fauna, particularly the near-absence of polymerid trilobites, and the taphonomy of the soft-tissue-harbouring hypostome.", "keyphrases": ["trilobite", "digestive system", "gland", "hypostome", "crop"]}
{"id": "paleo.009828", "title": "Simulating the origins of life: The dual role of RNA replicases as an obstacle to evolution", "abstract": "Despite years of study, it is still not clear how life emerged from inanimate matter and evolved into the complex forms that we observe today. One of the most recognized hypotheses for the origins of life, the RNA World hypothesis, assumes that life was sparked by prebiotic replicating RNA chains. In this paper, we address the problems caused by the interplay between hypothetical prebiotic RNA replicases and RNA parasitic species. We consider the coexistence of parasite RNAs and RNA replicases as well as the impact of parasites on the further evolution of replicases. For these purposes, we used multi-agent modeling techniques that allow for realistic assumptions regarding the movement and spatial interactions of modeled species. The general model used in this study is based on work by Takeuchi and Hogeweg. Our results confirm that the coexistence of parasite RNAs and replicases is possible in a spatially extended system, even if we take into consideration more realistic assumptions than Takeuchi and Hogeweg. However, we also showed that the presence of trade-off that takes into the account an RNA folding process could still pose a serious obstacle to the evolution of replication. We conclude that this might be a cause for one of the greatest transitions in life that took place early in evolution\u2014the separation of the function between DNA templates and protein enzymes, with a central role for RNA species.", "keyphrases": ["rna", "parasite", "realistic assumption", "movement"]}
{"id": "10.1017/jpa.2018.1", "title": "Taxonomy of limnic Ostracoda (Crustacea) from the Quiric\u00f3 Formation, Lower Cretaceous, S\u00e3o Francisco basin, Minas Gerais State, Southeast Brazil", "abstract": "Abstract. \n The present work presents a detailed taxonomic study on Ostracoda from the Quiric\u00f3 Formation, Areado Group, S\u00e3o Francisco Basin, Brazil. The samples were collected from three outcrops in the Minas Gerais State: Tereza Farm (Jo\u00e3o Pinheiro Municipality), and from the banks of the S\u00e3o Jos\u00e9 and Quiric\u00f3 creeks (Presidente Oleg\u00e1rio Municipality). Sixteen ostracode species were recovered: Harbinia alta, Harbinia aff. H. angulata, Harbinia aff. H. crepata, Harbinia aff. H. salitrensis, Harbinia symmetrica, Brasacypris fulfaroi, Brasacypris ovum, Cypridea conjugata, Cypridea hystrix, Cypridea infima, Cypridea jequiensis, Neuquenocypris (Protoneuquenocypris) antiqua, Penthesilenula martinsi, Penthesilenula pintoi new species, Alicenula longiformis new species, and Timiriasevia sanfranciscanensis new species. With the recovery of well-preserved specimens, it was possible to observe new characteristics in Brasacypris ovum, Cypridea conjugata, C. hystrix, and C. infima, and propose emendments to them. Additionally, three new species are described: Penthesilenula pintoi n. sp., Alicenula longiformis, n. sp., and Timiriasevia sanfranciscanensis n. sp. To date, the genus Timiriasevia had not been recorded in strata from Brazil. Also, Darwinula martinsi is reassigned to the genus Penthesilenula. Several species herein recorded are also found in other Brazilian continental basins, as well as in African and Argentinian basins, contributing to the knowledge of Brazilian Cretaceous continental deposits.", "keyphrases": ["s\u00e3o francisco basin", "cypridea jequiensis", "penthesilenula martinsi"]}
{"id": "paleo.007080", "title": "CRANIAL ANATOMY OF ERLIKOSAURUS ANDREWSI (DINOSAURIA, THERIZINOSAURIA): NEW INSIGHTS BASED ON DIGITAL RECONSTRUCTION", "abstract": "The skull of Erlikosaurus andrewsi from the Upper Cretaceous Baishin Tsav locality of Mongolia represents the only known three-dimensionally preserved and nearly complete skull of a therizinosaurian. Computed tomographic (CT) scanning of the original specimen and three-dimensional visualization techniques allow the cranial skeleton to be digitally prepared, disarticulated, and restored. Here, we present a detailed description of the restored skull morphology and the individual cranial elements, including visualization of the internal neurovascular and pneumatic structures. Information gained from this study is used in a revised and emended diagnosis for E. andrewsi. A reappraisal of the evolutionary and functional changes in the cranial skeleton as provided by this study supports prior proposals that a keratinous sheath or rhamphotheca was developed early in the evolution of Therizinosauria. Paralleled by the reduction of functional and replacement teeth, this development indicates a shift in the manner of food processing/procurement at the tip of the snout. Extensive pneumatization of the braincase, most evidently developed in E. andrewsi in comparison with other known therizinosaurians, appears to have led to a reduction of the adductor musculature and thus the potential bite force in derived therizinosaurians. In addition, the application of digital data, as presented in this study, introduces a novel way to document fossil data that will allow for morphological and anatomical data to be made widely accessible.", "keyphrases": ["therizinosauria", "skull", "mongolia", "rhamphotheca"]}
{"id": "paleo.001000", "title": "Homeotic shift at the dawn of the turtle evolution", "abstract": "All derived turtles are characterized by one of the strongest reductions of the dorsal elements among Amniota, and have only 10 dorsal and eight cervical vertebrae. I demonstrate that the Late Triassic turtles, which represent successive stages of the shell evolution, indicate that the shift of the boundary between the cervical and dorsal sections of the vertebral column occurred over the course of several million years after the formation of complete carapace. The more generalized reptilian formula of at most seven cervicals and at least 11 dorsals is thus plesiomorphic for Testudinata. The morphological modifications associated with an anterior homeotic change of the first dorsal vertebra towards the last cervical vertebra in the Triassic turtles are partially recapitulated by the reduction of the first dorsal vertebra in crown-group Testudines, and they resemble the morphologies observed under laboratory conditions resulting from the experimental changes of Hox gene expression patterns. This homeotic shift hypothesis is supported by the, unique to turtles, restriction of Hox-5 expression domains, somitic precursors of scapula, and brachial plexus branches to the cervical region, by the number of the marginal scute-forming placodes, which was larger in the Triassic than in modern turtles, and by phylogenetic analyses.", "keyphrases": ["vertebrae", "late triassic turtle", "morphology"]}
{"id": "paleo.000663", "title": "Reorganization of sea urchin gene regulatory networks at least 268 million years ago as revealed by oldest fossil cidaroid echinoid", "abstract": "Echinoids, or sea urchins, are rare in the Palaeozoic fossil record, and thus the details regarding the early diversification of crown group echinoids are unclear. Here we report on the earliest probable crown group echinoid from the fossil record, recovered from Permian (Roadian-Capitanian) rocks of west Texas, which has important implications for the timing of the divergence of crown group echinoids. The presence of apophyses and rigidly sutured interambulacral areas with two columns of plates indicates this species is a cidaroid echinoid. The species, Eotiaris guadalupensis, n. sp. is therefore the earliest stem group cidaroid. The occurrence of this species in Roadian strata pushes back the divergence of cidaroids and euechinoids, the clades that comprise all living echinoids, to at least 268.8 Ma, ten million years older than the previously oldest known cidaroid. Furthermore, the genomic regulation of development in echinoids is amongst the best known, and this new species informs the timing of large-scale reorganization in echinoid gene regulatory networks that occurred at the cidaroid-euechinoid divergence, indicating that these changes took place by the Roadian stage of the Permian.", "keyphrases": ["regulatory network", "crown group echinoid", "divergence", "eotiaris guadalupensis"]}
{"id": "10.1093/isd/ixac017", "title": "Estimating the Drivers of Diversification of Stoneflies Through Time and the Limits of Their Fossil Record", "abstract": "Abstract Deciphering the timing of lineage diversification and extinction has greatly benefited in the last decade from methodological developments in fossil-based analyses. If these advances are increasingly used to study the past dynamics of vertebrates, other taxa such as insects remain relatively neglected. Our understanding of how insect clades waxed and waned or of the impact of major paleoenvironmental changes during their periods of diversification and extinction (mass extinction) are rarely investigated. Here, we compile and analyze the fossil record of Plecoptera (1,742 vetted occurrences) to investigate their genus-level diversification and diversity dynamics using a Bayesian process-based model that incorporates temporal preservation biases. We found that the Permian-Triassic mass extinction has drastically impacted Plecoptera, while the Cretaceous Terrestrial Revolution corresponds with a turnover of plecopteran fauna. We also unveiled three major gaps in the plecopteran fossil record: the Carboniferous-Permian transition, the late Early Cretaceous, and the late Cenomanian to Bartonian, which will need to be further investigated. Based on the life history of extant Plecoptera, we investigate the correlations between their past dynamic and a series of biotic (Red Queen hypothesis) and abiotic (Court Jester hypothesis) factors. These analyses highlight the major role of continental fragmentation in the evolutionary history of stoneflies, which is in line with phylogeny-based biogeographic analyses showing how vicariance drove their diversification. Our study advocates analyzing the fossil record with caution, while attempting to unveil the diversification and extinction periods plus the likely triggers of these past dynamics of diversification.", "keyphrases": ["diversification", "stonefly", "insect", "plecoptera"]}
{"id": "10.1146/annurev.ecolsys.35.021103.105715", "title": "CONSEQUENCES OF THE CRETACEOUS/PALEOGENE MASS EXTINCTION FOR MARINE ECOSYSTEMS", "abstract": "\u25aa Abstract\u2002One of the greatest mass extinctions in Earth's history occurred at the end of the Cretaceous era, sixty-five million years (Myr) ago. Considerable evidence indicates that the impact of a large asteroid or comet was the ultimate cause of this extraordinary event. At the time of mass extinction, the organic flux to the deep sea collapsed, and production of calcium carbonate by marine plankton radically declined. These biogeochemical processes did not fully recover for a few million years. The drastic decline and long lag in final recovery of these processes are most simply explained as consequences of open-ocean ecosystem alteration by the mass extinction. If this explanation is correct, the extent and timing of marine biogeochemical recovery from the end-Cretaceous event was ultimately contingent on the extent and timing of open-ocean ecosystem recovery. The biogeochemical recovery may in turn have created new evolutionary opportunities for a diverse array of marine organisms.", "keyphrases": ["organic flux", "deep sea", "new evolutionary opportunity", "marine organism"]}
{"id": "10.1080/02724634.1983.10011954", "title": "Cranial osteology and morphology of the type specimen of Maiasaura peeblesorum (Ornithischia: Hadrosauridae), with a discussion of its phylogenetic position", "abstract": "ABSTRACT Maiasaum peeblesorum has a number of primitive characteristics, including an elongated facial region, restricted nares, deflected premaxillae, and an apparent remnant of the supraorbital fenestra, all of which are more common to the iguanodonts than to other hadrosaurs. It also has an incipient crest similar to that of Prosaurolophus, and posterior skull elements similar to Brachylophosaurus. The anterior premaxillary foramina may have served the function of vocalization or possibly for passage of olfactory organs. Growth stages of the dentary teeth indicate that the \u201cbudding teeth\u201d were small enough to have been introduced into the alveoli through \u201cspecial foramina.\u201d Individual tooth growth, from implantation to occlusion, occurred with initial growth of the apex and continued backward. Disregarding the nasal/frontal crest as a feature warranting separate subfamilial status, and thus following Steinberg's classification of hadrosaurs, Maiasaura is placed into the subfamily Hadrosaurinae. Western...", "keyphrases": ["morphology", "foramina", "tooth"]}
{"id": "10.1093/sysbio/syt007", "title": "Paleo-drainage basin connectivity predicts evolutionary relationships across three Southeast Asian biodiversity hotspots.", "abstract": "Understanding factors driving diversity across biodiversity hotspots is critical for formulating conservation priorities in the face of ongoing and escalating environmental deterioration. While biodiversity hotspots encompass a small fraction of Earth's land surface, more than half the world's plants and two-thirds of terrestrial vertebrate species are endemic to these hotspots. Tropical Southeast (SE) Asia displays extraordinary species richness, encompassing four biodiversity hotspots, though disentangling multiple potential drivers of species richness is confounded by the region's dynamic geological and climatic history. Here, we use multilocus molecular genetic data from dense multispecies sampling of freshwater fishes across three biodiversity hotspots, to test the effect of Quaternary climate change and resulting drainage rearrangements on aquatic faunal diversification. While Cenozoic geological processes have clearly shaped evolutionary history in SE Asian halfbeak fishes, we show that paleo-drainage re-arrangements resulting from Quaternary climate change played a significant role in the spatiotemporal evolution of lowland aquatic taxa, and provide priorities for conservation efforts.", "keyphrases": ["quaternary climate change", "paleo-drainage re-arrangement", "spatiotemporal evolution"]}
{"id": "paleo.002215", "title": "Pelagiella exigua, an early Cambrian stem gastropod with chaetae: lophotrochozoan heritage and conchiferan novelty", "abstract": "Exceptionally well\u2010preserved impressions of two bundles of bristles protrude from the apertures of small, spiral shells of Pelagiella exigua, recovered from the Kinzers Formation (Cambrian, Stage 4, \u2018Olenellus Zone\u2019, c. 512 Ma) of Pennsylvania. These impressions are inferred to represent clusters of chitinous chaetae, comparable to those borne by annelid parapodia and some larval brachiopods. They provide an affirmative test in the early metazoan fossil record of the inference, from phylogenetic analyses of living taxa, that chitinous chaetae are a shared early attribute of the Lophotrochozoa. Shells of Pelagiella exhibit logarithmic spiral growth, microstructural fabrics, distinctive external sculptures and muscle scars characteristic of molluscs. Hence, Pelagiella has been regarded as a stem mollusc, a helcionelloid expressing partial torsion, an untorted paragastropod, or a fully torted basal member of the gastropod crown group. The inference that its chaeta\u2010bearing appendages were anterior\u2013lateral, based on their probable functions, prompts a new reconstruction of the anatomy of Pelagiella, with a mainly anterior mantle cavity. Under this hypothesis, two lateral\u2013dorsal grooves, uniquely preserved in Pelagiella atlantoides, are interpreted as sites of attachment for a long left ctenidium and a short one, anteriorly on the right. The orientation of Pelagiella and the asymmetry of its gills, comparable to features of several living vetigastropods, nominate it as the earliest fossil mollusc known to exhibit evidence of the developmental torsion characteristic of gastropods. This key adaptation facilitated an evolutionary radiation, slow at first and rapid during the Ordovician, that gave rise to the remarkable diversification of the Gastropoda.", "keyphrases": ["chaeta", "kinzers formation", "pennsylvania"]}
{"id": "paleo.012111", "title": "New Horned Dinosaurs from Utah Provide Evidence for Intracontinental Dinosaur Endemism", "abstract": "Background During much of the Late Cretaceous, a shallow, epeiric sea divided North America into eastern and western landmasses. The western landmass, known as Laramidia, although diminutive in size, witnessed a major evolutionary radiation of dinosaurs. Other than hadrosaurs (duck-billed dinosaurs), the most common dinosaurs were ceratopsids (large-bodied horned dinosaurs), currently known only from Laramidia and Asia. Remarkably, previous studies have postulated the occurrence of latitudinally arrayed dinosaur \u201cprovinces,\u201d or \u201cbiomes,\u201d on Laramidia. Yet this hypothesis has been challenged on multiple fronts and has remained poorly tested. Methodology/Principal Findings Here we describe two new, co-occurring ceratopsids from the Upper Cretaceous Kaiparowits Formation of Utah that provide the strongest support to date for the dinosaur provincialism hypothesis. Both pertain to the clade of ceratopsids known as Chasmosaurinae, dramatically increasing representation of this group from the southern portion of the Western Interior Basin of North America. Utahceratops gettyi gen. et sp. nov.\u2014characterized by short, rounded, laterally projecting supraorbital horncores and an elongate frill with a deep median embayment\u2014is recovered as the sister taxon to Pentaceratops sternbergii from the late Campanian of New Mexico. Kosmoceratops richardsoni gen. et sp. nov.\u2014characterized by elongate, laterally projecting supraorbital horncores and a short, broad frill adorned with ten well developed hooks\u2014has the most ornate skull of any known dinosaur and is closely allied to Chasmosaurus irvinensis from the late Campanian of Alberta. Conclusions/Significance Considered in unison, the phylogenetic, stratigraphic, and biogeographic evidence documents distinct, co-occurring chasmosaurine taxa north and south on the diminutive landmass of Laramidia. The famous Triceratops and all other, more nested chasmosaurines are postulated as descendants of forms previously restricted to the southern portion of Laramidia. Results further suggest the presence of latitudinally arrayed evolutionary centers of endemism within chasmosaurine ceratopsids during the late Campanian, the first documented occurrence of intracontinental endemism within dinosaurs.", "keyphrases": ["endemism", "landmass", "late campanian", "western interior seaway", "exclusive clade"]}
{"id": "paleo.005405", "title": "Predation by Drilling Gastropods and Asteroids Upon Mussels in Rocky Shallow Shores of Southernmost South America: Paleontological Implications", "abstract": "To achieve a better understanding of predation pattern recorded in the fossil record it is essential to study predator-prey interactions in the modern seas. It includes the data collected from the field observations as well as from the experiments in captivity. Such an approach allows recognition of the bioeroders, its description and also provides quantification of these interactions. This work offers a case study of the traces of predation resulting from the predator-prey interactions between three mussels: Mytilus chilensis, Brachidontes purpuratus, and Aulacomya atra; and their five natural enemies: the gastropods Trophon geversianus, Xymenopsis muriciformis, and Acanthina monodon, and the asteroids Cosmasterias lurida and Anasterias antarctica living along the intertidal and/or subtidal rocky shores in Tierra del Fuego. The predatory damage to mussel shells varies according to the predator and prey species and techniques for attacking prey are highly specialized. A. monodon drills a hole in B. purpuratus but uses the outer lip of its shell as a wedge to open the valves of M. chilensis and A. atra. T. geversianus always makes holes, but while it drills the valve walls of M. chilensis, it prefers to drill the valve edges of A. atra and B. purpuratus, with different characteristic patterns. Usually the shells of mussels killed by C. lurida do not suffer from any mechanical damage, but some other shells were crushed or fractured along the margins. Comparatively, time required to successfully attack a prey was shorter in C. lurida (24 hours), followed by A. monodon (36 hours), and longer in T. geversianus (9 to 10 days). Traces of predation are not randomly distributed across size classes of mussel prey, reflecting selectivity for a particular size class. Also, drill holes are usually placed at specific sectors of the shell, indicating site selectivity. These observations offer some paleontological implications for investigating the pattern of predation in fossil record. They show that different patterns of shell damage can be due to different predator species (e.g., wall vs. edge drillings), although the same predator species can leave different marks when consuming different prey (e.g., T. geversianus). Most disconcerting for paleontologists are cases of predation which do not leave any marks on the prey shell detectable in the fossil record (e.g., predation by asteroids), or leave ambiguous marks (A. monodon when preying with the spine). In conclusion, besides the opportunity to identify some traces of predation by drilling gastropods in fossil mussels, this work gives criteria to address predation in some particular paleontological cases that would otherwise be dismissed by researchers.", "keyphrases": ["gastropod", "paleontological implication", "mytilus chilensis", "predator specie"]}
{"id": "10.1006/jhev.1997.0177", "title": "EMG of the human flexor pollicis longus muscle: implications for the evolution of hominid tool use.", "abstract": "Modern humans possess a distinct and well-developed flexor pollicis longus muscle, an extrinsic thumb flexor which is \"either rudimentary or absent\" in great apes (Straus, 1942, p. 228). Previous workers (e.g., Napier, 1962; Susman, 1988) have related the origin of a well-developed flexor pollicis longus muscle to the acquisition of precision grasping and stone tool making capabilities in early hominids. The proposed functional association between flexor pollicis longus activity, precision grasping, and stone tool manufacture has, however, never been tested experimentally. This study uses electromyographic techniques (EMG) to investigate the role of flexor pollicis longus during a variety of tool making, tool using, and manipulatory behaviors in order to determine the functional and evolutionary significance of the human flexor pollicis longus muscle. Our results indicate that flexor pollicis longus is recruited during forceful tool using and stone tool making behaviors, regardless of the power or precision grip used to hold the tool. In particular, both stone tool use and stone tool making employing three- and four-jaw chuck precision grips elicit consistently high levels of FPL activity. Flexor pollicis longus activity increases most when resistance is increased to the thumb's volar pad during these hammering, cutting, and knapping behaviors. In contrast, we observed relatively low levels of flexor pollicis longus activity during the fine manipulation of food items, the making of slender wooden probes, and the use of these probes as tools. The paleontological, archaeological, and experimental data suggest that a well-developed flexor pollicis longus muscle functioned initially in the hominid lineage to stabilize the terminal pollical phalanx against loads applied to the thumb's apical pad during the frequent and forceful use of unmodified stones as tools.", "keyphrases": ["thumb", "stone tool use", "emg"]}
{"id": "paleo.009686", "title": "Evolutionary Patterns among Living and Fossil Kogiid Sperm Whales: Evidence from the Neogene of Central America", "abstract": "Kogiids are known by two living species, the pygmy and dwarf sperm whale (Kogia breviceps and K. sima). Both are relatively rare, and as their names suggest, they are closely related to the sperm whale, all being characterized by the presence of a spermaceti organ. However, this organ is much reduced in kogiids and may have become functionally different. Here we describe a fossil kogiid from the late Miocene of Panama and we explore the evolutionary history of the group with special attention to this evolutionary reduction. The fossil consists of cranial material from the late Tortonian (~7.5 Ma) Pi\u00f1a facies of the Chagres Formation in Panama. Detailed comparison with other fossil and extant kogiids and the results of a phylogenetic analysis place the Panamanian kogiid, herein named Nanokogia isthmia gen. et sp. nov., as a taxon most closely related to Praekogia cedrosensis from the Messinian (~6 Ma) of Baja California and to Kogia spp. Furthermore our results show that reduction of the spermaceti organ has occurred iteratively in kogiids, once in Thalassocetus antwerpiensis in the early-middle Miocene, and more recently in Kogia spp. Additionally, we estimate the divergence between extant species of Kogia at around the late Pliocene, later than previously predicted by molecular estimates. Finally, comparison of Nanokogia with the coeval Scaphokogia cochlearis from Peru shows that these two species display a greater morphological disparity between them than that observed between the extant members of the group. We hypothesize that this reflects differences in feeding ecologies of the two species, with Nanokogia being more similar to extant Kogia. Nanokogia shows that kogiids have been part of the Neotropical marine mammal communities at least since the late Miocene, and gives us insight into the evolutionary history and origins of one of the rarest groups of living whales.", "keyphrases": ["sperm whale", "spermaceti organ", "evolutionary history"]}
{"id": "paleo.001162", "title": "Dipodidae (Mammalia, Rodentia) from the Paleogene of south-east Serbia", "abstract": "Isolated cheek teeth of the Asian dipodid Heosminthus primiveris from four early Oligocene localities in the Koritnica-Babu\u0161nica basin, south-east Serbia, are described. The record of the Paleogene Dipodidae of Central Asia and Europe is briefly discussed. The current view of the migration pattern of the Paleogene Dipodidae between central Asia and Europe is revised: the migration of Plesiosminthus into Europe during the late Oligocene was preceded by the immigration of Heosminthus into the Serbo-Macedonian high (S. E. Europe) during the early Oligocene.", "keyphrases": ["oligocene", "eocene assemblage", "small mammal", "anatolia"]}
{"id": "10.1105/tpc.15.00157", "title": "Horsetails Are Ancient Polyploids: Evidence from Equisetum giganteum[OPEN]", "abstract": "An ancient polypoloidy event in horsetails during the late Cretaceous predates the divergence of today's extant species and may have contributed to the longevity of the genus Equisetum. Horsetails represent an enigmatic clade within the land plants. Despite consisting only of one genus (Equisetum) that contains 15 species, they are thought to represent the oldest extant genus within the vascular plants dating back possibly as far as the Triassic. Horsetails have retained several ancient features and are also characterized by a particularly high chromosome count (n = 108). Whole-genome duplications (WGDs) have been uncovered in many angiosperm clades and have been associated with the success of angiosperms, both in terms of species richness and biomass dominance, but remain understudied in nonangiosperm clades. Here, we report unambiguous evidence of an ancient WGD in the fern linage, based on sequencing and de novo assembly of an expressed gene catalog (transcriptome) from the giant horsetail (Equisetum giganteum). We demonstrate that horsetails underwent an independent paleopolyploidy during the Late Cretaceous prior to the diversification of the genus but did not experience any recent polyploidizations that could account for their high chromosome number. We also discuss the specific retention of genes following the WGD and how this may be linked to their long-term survival.", "keyphrases": ["longevity", "wgd", "equisetum giganteum", "horsetail"]}
{"id": "paleo.000780", "title": "Ecological Changes in Coyotes (Canis latrans) in Response to the Ice Age Megafaunal Extinctions", "abstract": "Coyotes (Canis latrans) are an important species in human-inhabited areas. They control pests and are the apex predators in many ecosystems. Because of their importance it is imperative to understand how environmental change will affect this species. The end of the Pleistocene Ice Age brought with it many ecological changes for coyotes and here we statistically determine the changes that occurred in coyotes, when these changes occurred, and what the ecological consequences were of these changes. We examined the mandibles of three coyote populations: Pleistocene Rancho La Brean (13\u201329 Ka), earliest Holocene Rancho La Brean (8\u201310 Ka), and Recent from North America, using 2D geometric morphometrics to determine the morphological differences among them. Our results show that these three populations were morphologically distinct. The Pleistocene coyotes had an overall robust mandible with an increased shearing arcade and a decreased grinding arcade, adapted for carnivory and killing larger prey; whereas the modern populations show a gracile morphology with a tendency toward omnivory or grinding. The earliest Holocene populations are intermediate in morphology and smallest in size. These findings indicate that a niche shift occurred in coyotes at the Pleistocene/Holocene boundary \u2013 from a hunter of large prey to a small prey/more omnivorous animal. Species interactions between Canis were the most likely cause of this transition. This study shows that the Pleistocene extinction event affected species that did not go extinct as well as those that did.", "keyphrases": ["canis latran", "north america", "holocene boundary", "species interaction"]}
{"id": "10.1080/08912963.2011.621083", "title": "Revised paleoecology of placodonts \u2013 with a comment on \u2018The shallow marine placodont Cyamodus of the central European Germanic Basin: its evolution, paleobiogeography and paleoecology\u2019 by C.G. Diedrich (Historical Biology, iFirst article, 2011, 1\u201319, doi: 10.1080/08912963.2011.575938)", "abstract": "A recent article published by Diedrich (2011a, Hist Biol. iFirst online, 1\u201319, doi: 10.1080/08912963.2011.575938) aspired to provide a complete revision of the known material of the placodont genus Cyamodus Meyer, 1863 from the Germanic Basin of central Europe. It is the latest in a series of similar articles by the same author (see Diedrich 2010, Palaeogeogr Palaeoclimatol Palaeoecol. 285(3\u20134):287\u2013306; 2011b, Nat Sci. 3(1):9\u201327 for overview) focussing on the European members of the Placodontia (Reptilia: Sauropterygia), a diverse group of enigmatic marine reptiles known from Triassic shallow marine deposits. In a similar fashion to some previous works by Diedrich (see Tintori 2011, Palaeogeogr Palaeoclimatol Palaeoecol. 300(1\u20134):205\u2013207 for similar points of criticism), this newest article demonstrates a narrow scope of presenting and discussing data, including omitted articles relevant to the topic, and over-interpretation of results, all with the aim of embedding the idea of placodonts being herbivorous Triassic \u2018sea cows\u2019 feeding on macroalgae (Diedrich 2010, 2011b). The present contribution is intended to clarify mistakes and misinterpretations made by Diedrich (2011a), to incorporate vital citations previously omitted which allow alternative interpretations, and to put the paper into perspective by including a more general evolutionary and paleoecological overview of the remaining placodonts.", "keyphrases": ["shallow-marine realm", "aquatic reptile", "plant material"]}
{"id": "10.1111/j.1095-8312.2004.00361.x", "title": "Radiating in a river: systematics, molecular genetics and morphological differentiation of viviparous freshwater gastropods endemic to the Kaek River, central Thailand (Cerithioidea, Pachychilidae)", "abstract": "Speciation in the context of adaptive radiation is regarded as a key process in the creation of biodiversity. While several lacustrine species flocks provide ideal models for elucidating the underlying evolutionary mechanisms, riverine radiations are both rarely known and studied. The Kaek River, a third-order tributary of the Nan River and Chao Praya drainage in central Thailand, harbours an exceptional endemic species assemblage of morphologically distinct, viviparous pachychilid gastropods. Our systematic revision, combining a morphological and molecular genetics approach, reveals the sympatric existence of at least seven species of the genus Brotia that is widespread in rivers of South-east Asia where usually only two species at the most coexist. At eight locations along a 100-kilometre stretch of the Kaek River, we found the syntopic occurrence of two to three species that are separated by specific habitat preferences and exhibit trophic specialization in their radula morphology. Phylogenetic analyses (using MP, NJ, ML and Bayesian inference statistics) of partial COI and 16S sequence data of 17 samples from six species occurring sympatrically and parapatrically, respectively, in the Kaek River drainage (plus the type species B. pagodula as outgroup) indicate monophyly of all these endemic species. Brotia solemiana, which also occurs in the Loei River, a tributary of the Mekong drainage system, was found to be sister to all other Kaek River pachychilids. The distinctive morphotypes, proposed here to represent biospecies, do not show high levels of genetic variation consistent with long periods of reproductive isolation. This suggests a relatively recent origin of this intrariverine radiation and rapid morphological divergence in the Kaek River Brotia. Recent diversification combined with ecological separation and trophic specialization parallels conditions found, albeit on a more specious level, in the lacustrine species flock of the closely related pachychilid genus Tylomelania, which is endemic to ancient lakes on the Indonesian island of Sulawesi. We discuss and compare the allopatric and ecological aspects of speciation in this unique riverine radiation and outline a putative historical biogeography of the Kaek River species, employing the most recent geological and palaeohydrological data for Thailand. \u00a9 2004 The Linnean Society of London, Biological Journal of the Linnean Society, 2004, 82, 275\u2010311.", "keyphrases": ["gastropod", "kaek river", "speciation", "lake"]}
{"id": "paleo.001186", "title": "ENIGMATIC WORM\u2010LIKE ORGANISMS FROM THE UPPER DEVONIAN OF NEW YORK: AN APPARENT EXAMPLE OF EDIACARAN\u2010LIKE PRESERVATION", "abstract": "Abstract:\u2002 The supposed polychaete annelid Protonympha salicifolia, from the Upper Devonian (Frasnian) of New York State, USA, is redescribed. P.\u2003salicifolia has a bilateral and segmented body, but appears to have a \u2018mattress\u2010like\u2019 construction with blade\u2010like extensions along the margins. The affinities of P.\u2003salicifolia remain unresolved, but a proposed relationship to the annelids is unlikely. The preservation of the three known fossils, as mouldic imprints in sandstones, is strongly reminiscent of the circumstances associated with Ediacaran fossilization, and as such is an anomalous occurrence of such soft\u2010part preservation in Phanerozoic sediments. Material associated with these enigmatic fossils has been referred to Palaeochaeta devonica, and also compared with the annelids. Such an assignment is also rejected. These fossils appear to be arthropodan, and are possibly myriapods. A supposed example of Protonympha (\u2018P\u2019.\u2003marcellensis) from the Middle Devonian of New York State is now excluded from this genus, and it may be a crustacean.", "keyphrases": ["upper devonian", "protonympha", "extension", "palaeochaeta devonica", "marcellensis"]}
{"id": "10.1111/1475-4983.00242", "title": "The Late Triassic Phytosaur Mystriosuchus Westphali, With A Revision of the Genus", "abstract": "Mystriosuchus westphali is based on a large, well\u2010preserved cranium and a snout fragment from the Stubensandstein (Norian) of south\u2010west Germany. The hypodigm is redescribed and new or poorly known cranial structures in phytosaurs are discussed. For the first time, the presence of a premaxillary crest is substantiated in a phytosaur. The type specimen shows a supernumerary occipital element (=\u2018tabular\u2019) that is probably fused to the parietal in other phytosaurs, and an orbitosphenoid. A computerised parsimony analysis confirms the hypothesis that Mystriosuchus is nested within Pseudopalatinae, the most derived clade of phytosaurs, and thus does not fall within basal phytosaurs. Mystriosuchus is characterised by five unique features (slit\u2010like interpremaxillary fossa, triangular cross\u2010section of the postorbito\u2010squamosal bar, strongly reduced posttemporal fenestra, and two features of the cranial sculpture), plus eight synapomorphies that also occur in some more distantly related taxa. Mystriosuchus westphali is diagnosed by, among other apomorphies, a distinct premaxillary crest, a squamosal\u2010proo\u00a8tic contact, absence of a posterior process of the squamosal, and a slit\u2010like posttemporal fenestra. The type species Mystriosuchus planirostris shows, most significantly, the naris facing forward anteriorly and upward posteriorly, and the longest rostrum and the highest degree of depression of the supratemporal opening in any phytosaur. Mystriosuchus exemplifies a common pattern in phytosaurids in being a genus that includes a gracile, elongated, slender\u2010snouted and a more robust species with a broader, often crested snout. This study demonstrates that a detailed analysis of the cranial anatomy and the rigorous application of cladistic principles to identified character states help to clarify current inconsistencies in the taxonomy and nomenclature of phytosaurs.", "keyphrases": ["phytosaur", "mystriosuchus", "germany"]}
{"id": "10.1139/e03-048", "title": "Paleoenvironmental analysis of the late Neoproterozoic Mistaken Point and Trepassey formations, southeastern Newfoundland", "abstract": "The Mistaken Point and Trepassey formations (Conception and St. John's groups, respectively) comprise a terminal Neoproterozoic, deep-marine succession of fine-grained turbidites and volcanogenic deposits that are part of the Avalonian Terrane. Debris-flow beds, slumped units, the low dispersion of turbidity-current paleoflow directions, and the absence of wave-generated structures together indicate that the sediment was deposited on a deep-water, southeast- facing slope. Channels were not present in the study area. The upward increase in the abundance of slump structures suggests that these units represent toe-of-slope and mid-slope environments, respectively. These units prograded over basin-floor deposits of the Drook and Briscal formations, which have (axial) paleocurrent directions that are orthogonal to the inferred downslope flow that characterized the overlying deposits. Within the Mistaken Point and Trepassey formations, a diverse assemblage of soft-bodied, non-phototrophic Ediacaran organisms is...", "keyphrases": ["trepassey formation", "succession", "deep-water"]}
{"id": "paleo.007372", "title": "Relationships of the Malagasy fauna during the Late Cretaceous: Northern or Southern routes?", "abstract": "Conjectures about the Cretaceous and post-Cretaceous vertebrate faunas of Madagascar are generally based on the fact that these faunas display similarities to those of South America, and that Africa lacks taxa that are common to Madagascar and South America. In order to account for this distribution, two ways of dispersal bypassing Africa have been proposed.", "keyphrases": ["route", "madagascar", "south america"]}
{"id": "paleo.004024", "title": "MESOZOIC TO EARLY QUATERNARY MAMMAL FAUNAS OF VICTORIA, SOUTH\u2010EAST AUSTRALIA", "abstract": "Abstract:\u2002 Twenty\u2010two terrestrial and over 20 marine mammal faunas are currently recognized in the fossil record of Victoria, representing one of the most complete records of mammal evolution in Australia. Although the earliest recorded terrestrial mammals come from the Early Cretaceous, the majority of the faunas are concentrated in the Pliocene and Pleistocene, whereas the marine mammal record spans the Late Oligocene\u2013Holocene. Despite the generally fragmentary nature of the fossil remains, many of the faunas are diverse and offer insights into the changes in palaeoecology and palaeoenvironmental conditions of the region over time. The terrestrial mammal faunas follow the global trend with the appearance of more arid\u2010adapted species in the late Pliocene; however, a number of Pliocene\u2013Pleistocene coastal sites indicate the continued presence of wet forest refugia, with several relict species occurring in the Early Pleistocene. Most of the faunas are well dated, providing a basis for the production of a biostratigraphic framework, essential for the more accurate dating of mammals in Australia. Two new diverse mammal sites, Childers Cove and Portland, are a welcome addition to the Pliocene records of both terrestrial and marine mammals. Marine mammal research is only in its early stages, but the Victorian record is fundamental in understanding the evolution of cetaceans in the southern oceans. The known diversity of species has increased substantially as a result of recent research. Some well\u2010preserved specimens, including complete skulls, have implications for cetacean systematics, including basal mysticetes. However, much more work needs to be focused on the cataloguing, preparation, description and interpretation of the faunas to take full advantage of this excellent record.", "keyphrases": ["terrestrial mammal", "portland", "cetacean"]}
{"id": "paleo.012958", "title": "Back to the bones: do muscle area assessment techniques predict functional evolution across a macroevolutionary radiation?", "abstract": "Measures of attachment or accommodation area on the skeleton are a popular means of rapidly generating estimates of muscle proportions and functional performance for use in large-scale macroevolutionary studies. Herein, we provide the first evaluation of the accuracy of these muscle area assessment (MAA) techniques for estimating muscle proportions, force outputs and bone loading in a comparative macroevolutionary context using the rodent masticatory system as a case study. We find that MAA approaches perform poorly, yielding large absolute errors in muscle properties, bite force and particularly bone stress. Perhaps more fundamentally, these methods regularly fail to correctly capture many qualitative differences between rodent morphotypes, particularly in stress patterns in finite-element models. Our findings cast doubts on the validity of these approaches as means to provide input data for biomechanical models applied to understand functional transitions in the fossil record, and perhaps even in taxon-rich statistical models that examine broad-scale macroevolutionary patterns. We suggest that future work should go back to the bones to test if correlations between attachment area and muscle size within homologous muscles across a large number of species yield strong predictive relationships that could be used to deliver more accurate predictions for macroevolutionary and functional studies.", "keyphrases": ["muscle property", "bite force", "bone stress", "attachment area"]}
{"id": "paleo.005564", "title": "The evolution of human and ape hand proportions", "abstract": "Human hands are distinguished from apes by possessing longer thumbs relative to\nfingers. However, this simple ape-human dichotomy fails to provide an adequate\nframework for testing competing hypotheses of human evolution and for reconstructing\nthe morphology of the last common ancestor (LCA) of humans and chimpanzees. We\ninspect human and ape hand-length proportions using phylogenetically informed\nmorphometric analyses and test alternative models of evolution along the anthropoid\ntree of life, including fossils like the plesiomorphic ape Proconsul heseloni\nand the hominins Ardipithecus ramidus and Australopithecus sediba. Our\nresults reveal high levels of hand disparity among modern hominoids, which are\nexplained by different evolutionary processes: autapomorphic evolution in hylobatids\n(extreme digital and thumb elongation), convergent adaptation between chimpanzees\nand orangutans (digital elongation) and comparatively little change in gorillas and\nhominins. The human (and australopith) high thumb-to-digits ratio required little\nchange since the LCA, and was acquired convergently with other highly dexterous\nanthropoids.", "keyphrases": ["hand", "lca", "chimpanzee"]}
{"id": "10.1073/pnas.1717762115", "title": "Four millennia of Iberian biomolecular prehistory illustrate the impact of prehistoric migrations at the far end of Eurasia", "abstract": "Significance The gene pool of modern Europeans was shaped through prehistoric migrations that reached the Western Mediterranean last. Obtaining biomolecular data has been challenging due to poor preservation related to adverse climatic conditions in this region. Here, we study the impact of prehistoric (Neolithic\u2013Bronze Age) migrations in Iberia by analyzing genomic and dietary data, demonstrating that farming practices were introduced by a population genetically distinct from the first farmers in central and northern Europe. After recovering from a founder bottleneck, these first farmers mixed with local hunter-gatherers. Finally, post-Neolithic migrations had a much smaller impact on the Iberian gene pool than they had in other parts of Europe. Stable isotope analysis reveals a homogenous terrestrial diet throughout this period. Population genomic studies of ancient human remains have shown how modern-day European population structure has been shaped by a number of prehistoric migrations. The Neolithization of Europe has been associated with large-scale migrations from Anatolia, which was followed by migrations of herders from the Pontic steppe at the onset of the Bronze Age. Southwestern Europe was one of the last parts of the continent reached by these migrations, and modern-day populations from this region show intriguing similarities to the initial Neolithic migrants. Partly due to climatic conditions that are unfavorable for DNA preservation, regional studies on the Mediterranean remain challenging. Here, we present genome-wide sequence data from 13 individuals combined with stable isotope analysis from the north and south of Iberia covering a four-millennial temporal transect (7,500\u20133,500 BP). Early Iberian farmers and Early Central European farmers exhibit significant genetic differences, suggesting two independent fronts of the Neolithic expansion. The first Neolithic migrants that arrived in Iberia had low levels of genetic diversity, potentially reflecting a small number of individuals; this diversity gradually increased over time from mixing with local hunter-gatherers and potential population expansion. The impact of post-Neolithic migrations on Iberia was much smaller than for the rest of the continent, showing little external influence from the Neolithic to the Bronze Age. Paleodietary reconstruction shows that these populations have a remarkable degree of dietary homogeneity across space and time, suggesting a strong reliance on terrestrial food resources despite changing culture and genetic make-up.", "keyphrases": ["prehistoric migration", "europe", "neolithic", "expansion"]}
{"id": "paleo.003609", "title": "Taphonomy of the Fossil Insects of the Middle Eocene Kishenehn Formation", "abstract": "The lacustrine oil shales of the Coal Creek Member of the Kishenehn Formation in northwestern Montana comprise a relatively unstudied middle Eocene fossil insect locality. Herein, we detail the stratigraphic position of the fossiliferous unit, describe the insect fauna of the Coal Creek locality and document its bias towards very small but remarkably preserved insects. In addition, the depositional environment is examined and the mineral constituents of the laminations that comprise the varves of the Kishenehn oil shale are defined. Fifteen orders of insects have been recorded with the majority of all insects identified as aquatic with the families Chironomidae (Diptera) and Corixidae (Hemiptera) dominant. The presence of small aquatic insects, many of which are immature, the intact nature of >90% of the fossil insects and the presence of Daphnia ephippia, all indicate that the depositional environment was the shallow margin of a large freshwater lake. The fossil insects occur within fossilized microbial mat layers that comprise the bedding planes of the oil shale. Unlike the fossiliferous shales of the Florissant and Okanagan Highlands, the mats are not a product of diatomaceous algae nor are diatom frustules a component of the sediments or the varve structure. Instead, the varves are composed of very fine eolian siliciclastic silt grains overlaid with non-diatomaceous, possibly cyanobacteria-derived microbial mats which contain distinct traces of polyaromatic hydrocarbons. A distinct third layer composed of essentially pure calcite is present in the shale of some exposures and is presumably derived from the seasonal warming-induced precipitation of carbonate from the lake's waters. The Coal Creek locality presents a unique opportunity to study both very small middle Eocene insects not often preserved as compression fossils in most Konservat-Lagerst\u00e4tte and the processes that led to their preservation.", "keyphrases": ["fossil insect", "middle eocene", "fossiliferous shale", "algae"]}
{"id": "10.1111/j.1744-7917.2010.01378.x", "title": "Radiation of the Oriental phlebotomine sand flies (Diptera: Psychodidae)", "abstract": "Abstract\u2002 The historical biogeography of phlebotomine sand fly taxa Hertigia, Warileya, Phlebotomus (Idiophlebotomus), P. (Spelaeophlebotomus), P. (Anaphlebotomus), and P. (Euphlebotomus) and the Phlebotomus (Euphlebotomus) argentipes species complex was investigated using phylogenetic inference from comparative genital morphology, distribution of ancestral taxa, fossil evidence and geological age. Idiophlebotomus and Euphlebotomus occur in the Oriental region with one species from northeast Australia, whereas Anaphlebotomus occurs both in the Afro\u2010tropical and Oriental regions. These disjunct distribution patterns across the Oriental region and the present day distribution are likely to be vicariance due to break of Gondwanaland. Fossil records, extant taxa distribution, phylogenetic analysis of the Old World Phlebotominae and paleogeography suggest that ancestors of Idiophlebotomus and Euphlebotomus originated apparently in the Cimmerian continent of northern margin of Gondwanaland in the early Permian (290 million years ago, MYA) and subsequently radiated in the Mesozoic by tectonic vicariance. The Phlebotomus argentipes species complex occurs in the South and South\u2010east Asian countries and transmits the protozoan parasite Leishmania donovani that causes visceral leishmaniasis (Kala\u2010azar) in India, Bangladesh and Nepal. The phylogeography of P. argentipes was caused through vicariance followed by dispersal events from 5O MYA (the Eocene) until the Recent era.", "keyphrases": ["oriental phlebotomine sandfly", "phlebotomus fossil", "holocene copal"]}
{"id": "paleo.000874", "title": "The biogeography and ecology of the Cretaceous non-avian dinosaurs of Appalachia", "abstract": "The Cenomanian to Maastrichtian of the Late Cretaceous saw the flooding of the interior of North America by the Western Interior Seaway, which created the eastern landmass of Appalachia and the western landmass of Laramidia. Though Appalachian dinosaur faunas are poorly known, they are nevertheless important for understanding Cretaceous dinosaur paleobiogeography and ecology. In order to better track the vicariance of eastern and western North American dinosaur faunas over the duration of the Cretaceous, the former were compared with the latter from the Aptian to Maastrichtian Stages of the Late Cretaceous using several similarity indices. The data gathered from biogeographic similarity indices suggest that an almost completely homogenous North American dinosaur fauna found in the Early Cretaceous experienced significant vicariance, splitting into a Laramidian fauna differentiated by the presence of ceratopsids, pachycephalosaurids, saurolophids, lambeosaurines, ankylosaurids, therizinosaurids, and troodontids and an Appalachian fauna characterized by the lack of the aforementioned groups and the presence of non-hadrosaurid hadrosauroids, massive hadrosauroids, basal hadrosaurids, leptoceratopsians, \u201cintermediate\u201d-grade tyrannosauroids, and nodosaurids between the Cenomanian and Campanian, with these two faunas later experiencing limited dispersal after the disappearance of the Western Interior Seaway from the American Interior during the Maastrichtian. Dinosaur provincialism and ecology on Appalachia are also investigated and discussed. Though the fossil record of dinosaurs for parts of the Cretaceous is poor throughout North America and in the eastern portion of the continent especially, the analyses herein nevertheless allow for a greater glimpse at dinosaur biogeography and ecology in Appalachia and in North America generally during the time. Chase D. Brownstein. Research Associate, Stamford Museum & Nature Center, Stamford, CT. USA. chasethedinosaur@gmail.com", "keyphrases": ["ecology", "maastrichtian", "north america", "eastern landmass"]}
{"id": "paleo.012802", "title": "Vascularization and odontode structure of a dorsal ridge spine of Romundina stellina \u00d8rvig 1975", "abstract": "There are two types of dermal skeletons in jawed vertebrates: placoderms and osteichthyans carry large bony plates (macromery), whereas chondrichthyans and acanthodians are covered by small scales (micromery). Fin spines are one of the last large dermal structures found on micromeric taxa and offer a potential source of histology and morphology that can be compared to those found on macromeric groups. Dermal fin spines offer a variety of morphology but aspects of their growth modes and homology are unclear. Here, we provide detailed descriptions of the microstructure and growth of a dorsal ridge spine from the acanthothoracid placoderm, Romundina stellina, using virtual three-dimensional paleohistological datasets. From these data we identify several layers of dentine ornamentation covering the lateral surfaces of the spine and reconstructed their growth pattern. We show that this spine likely grew posteriorly and proximally from a narrow portion of bone located along the leading edge of the spine. The spine is similarly constructed to the scales with a few exceptions, including the absence of polarized fibers distributed throughout the bone and the presence of a thin layer of perichondral bone. The composition of the spine (semidentine odontodes, dermal bone, perichondral bone) is identical to that of the Romundina dermal plates. These results illustrate the similarities and differences between the dermal tissues in Romundina and indicate that the spine grew differently from the dentinous fin spines from extant and fossil chondrichthyans. The morphology and histology of Romundina is most similar to the fin spine of the probable stem osteichthyan Lophosteus, with a well-developed inner cellular bony base and star-shaped odontodes on the surface. Results from these studies will undoubtedly have impact on our understanding of fossil fin spine histology and evolution, contributing to the on-going revision of early gnathostome phylogeny.", "keyphrases": ["dorsal ridge spine", "dermal skeleton", "placoderm", "bony plate", "micromery"]}
{"id": "paleo.008431", "title": "First Evidence of Denticulated Dentition in Teleosaurid Crocodylomorphs", "abstract": "Teleosauridae was a group of largely marine Mesozoic crocodylomorphs, typically considered as akin to \u201cmarine gavials\u201d due to their elongate, tubular, polydont rostra that are indicative of a piscivorous diet. Here we show that these extinct crocodylomorphs were more anatomically, and perhaps ecologically, varied than previously thought. We report the first evidence of denticles in a teleosaurid tooth, revealed by scanning electron microscopic (SEM) analysis of a tooth from the holotype of \u201cSteneosaurus\u201d obtusidens. These denticles are cryptic, because they are microscopic, not contiguous along the carinae (instead forming short series), and are detectable only using SEM. This incipient denticle morphology is similar to that recently discovered in a closely related group of marine crocodylomorphs, the Metriorhynchidae. In particular, the denticulation morphology of \u201cSteneosaurus\u201d is similar to that of the geosaurin metriorhynchid Torvoneustes, indicating that these two taxa may have employed similar feeding styles and that \u201cS.\u201dobtusidens may have been a nearshore ecological analogue to the more offshore, fast-swimming geosaurins. Previous authors have considered \u201cS.\u201dobtusidens and Machimosaurus to be durophagous, but the discovery of denticulated teeth indicates that they had a more varied diet and feeding style, and included flesh slicing as part of their feeding toolkit. It is currently unknown how extensive denticulate carinae may be in Teleosauridae, and we hypothesise that cryptic denticles may also be present in other marine crocodylomorphs once they are subjected to SEM study.", "keyphrases": ["denticle", "carinae", "first evidence"]}
{"id": "paleo.013023", "title": "Controls on the evolution of Ediacaran metazoan ecosystems: A redox perspective", "abstract": "A growing number of detailed geochemical studies of Ediacaran (635\u2013541 Ma) marine successions have provided snapshots into the redox environments that played host to the earliest known metazoans. Whilst previous compilations have focused on the global evolution of Ediacaran water column redox chemistry, the inherent heterogeneity evident in palaeogeographically distinct environments demands a more dissected approach to better understand the nature, interactions and evolution of extrinsic controls on the development of early macrobenthic ecosystems. Here, we review available data of local\u2010scale redox conditions within a palaeogeographic and sequence stratigraphic framework, to explore the mechanisms controlling water column redox conditions and their potential impact on the record of metazoans. The openly connected Laurentian margin, North America (632\u2013540 Ma) and Nama basin, Namibia (550\u2013538 Ma), and the variably restricted Yangtze Block, South China (635\u2013520 Ma), show continued redox instability after the first fossil evidence for metazoans. This may support opportunistic benthic colonisation during periods of transient oxygenation amidst episodic upwelling of anoxic waters beneath a very shallow, fluctuating chemocline. The first skeletal metazoans appeared under conditions of continued redox stratification, such as those which characterise the Dengying Formation of the Yangtze Block and the Kuibis Subgroup of the Nama basin. Current data, however, suggests that successful metazoan reef\u2010building demanded more persistent oxia. We propose that cratonic positioning and migration throughout the Ediacaran Period, in combination with gradually increasing dissolved oxygen loading, may have provided a first\u2010order control on redox evolution through regulating circulation mechanisms in the Mirovian Ocean. Some unrestricted lower slope environments from mid\u2010high latitudes benefited from sustained oxygenation via downwelling, whilst transit of isolated cratons towards more equatorial positions stifled pervasive ventilation either through ineffective surface ocean mixing, Ekman\u2010induced upwelling, elevated surface ocean productivity or a combination of these processes.", "keyphrases": ["ecosystem", "geochemical study", "redox condition"]}
{"id": "10.1080/08912961003754945", "title": "Reptilian assemblages from the latest Cretaceous \u2013 Palaeogene phosphates of Morocco: from Arambourg to present time", "abstract": "Arambourg was the first to conduct methodical vertebrate palaeontological studies in the Oulad Abdoun and Ganntour phosphatic basins of Morocco between the 1930s and 1950s. As early as 1935, he identified the main stratigraphical levels of the phosphatic series, characterizing them by a specific association of vertebrates (mainly selachians), and proposed stratigraphical correlations between the phosphatic levels of these two basins. During the last decade, due to a French-Moroccan program of collaboration, vertebrate fossils have been collected in great abundance. Here we present an updated overview of the latest Cretaceous to Ypresian reptilian faunas from the Oulad Abdoun and Ganntour basins, on the basis of published data and new field records. In addition to advances in the study of the already known taxa (i.e., squamates, crocodyliforms, plesiosaurs), recent field works reveal new major reptilian taxa that were unknown (or undescribed) at Arambourg's time: very abundant and diversified marine chelonians (Maastrichtian to Ypresian), scarce dinosaurs and pterosaurs remains (Maastrichtian), and a well diversified marine avifauna (Thanetian and Ypresian). A significant increase in the number of described taxa (52 versus 13) and an improvement of the quality of the specimens found (articulated skeletons versus isolated remains) is worthy of consideration. The Maastrichtian reptilian assemblages are dominated by mosasaurid squamates whereas those of the Palaeogene are by the mirroring crocodyliforms (dyrosaurids and eusuchians).", "keyphrases": ["arambourg", "squamate", "crocodyliform"]}
{"id": "paleo.001406", "title": "Reappraisal of the Silurian placoderm Silurolepis and insights into the dermal neck joint evolution", "abstract": "Silurolepis platydorsalis, a Silurian jawed vertebrate originally identified as an antiarch, is here redescribed as a maxillate placoderm close to Qilinyu and is anteroposteriorly reversed as opposed to the original description. The cuboid trunk shield possesses three longitudinal cristae, obstanic grooves on the trunk shield and three median dorsal plates, all uniquely shared with Qilinyu. Further preparation reveals the morphology of the dermal neck joint, with slot-shaped articular fossae on the trunk shield similar to Qilinyu and antiarchs. However, new tomographic data reveal that Qilinyu uniquely bears a dual articulation between the skull roof and trunk shield, which does not fit into the traditional \u2018ginglymoid\u2019 and \u2018reverse ginglymoid\u2019 categories. An extended comparison in early jawed vertebrates confirms that a sliding-type dermal neck joint is widely distributed and other types are elaborated in different lineages by developing various laminae. Nine new characters related to the dermal neck joint are proposed for a new phylogenetic analysis, in which Silurolepis forms a clade with Qilinyu. The current phylogenetic framework conflicts with the parsimonious evolution of dermal neck joints in suggesting that the shared trunk shield characters between antiarchs and Qilinyu are independently acquired, and the sliding-type joint in Entelognathus is reversely evolved from the dual articulation in Qilinyu.", "keyphrases": ["silurian", "maxillate placoderm", "articulation"]}
{"id": "paleo.001599", "title": "Lower Cretaceous fossils from China shed light on the ancestral body plan of crown softshell turtles (Trionychidae, Cryptodira)", "abstract": "Pan-trionychids or softshell turtles are a highly specialized and widespread extant group of aquatic taxa with an evolutionary history that goes back to the Early Cretaceous. The earliest pan-trionychids had already fully developed the \u201cclassic\u201d softshell turtle morphology and it has been impossible to resolve whether they are stem members of the family or are within the crown. This has hindered our understanding of the evolution of the two basic body plans of crown-trionychids. Thus it remains unclear whether the more heavily ossified shell of the cyclanorbines or the highly reduced trionychine morphotype is the ancestral condition for softshell turtles. A new pan-trionychid from the Early Cretaceous of Zhejiang, China, Perochelys hengshanensis sp. nov., allows a revision of softshell-turtle phylogeny. Equal character weighting resulted in a topology that is fundamentally inconsistent with molecular divergence date estimates of deeply nested extant species. In contrast, implied weighting retrieved Lower Cretaceous Perochelys spp. and Petrochelys kyrgyzensis as stem trionychids, which is fully consistent with their basal stratigraphic occurrence and an Aptian-Santonian molecular age estimate for crown-trionychids. These results indicate that the primitive morphology for soft-shell turtles is a poorly ossified shell like that of crown-trionychines and that shell re-ossification in cyclanorbines (including re-acquisition of peripheral elements) is secondary.", "keyphrases": ["body plan", "early cretaceous", "phylogenetic position"]}
{"id": "paleo.009493", "title": "A Complete Mitochondrial Genome Sequence from a Mesolithic Wild Aurochs (Bos primigenius)", "abstract": "Background The derivation of domestic cattle from the extinct wild aurochs (Bos primigenius) has been well-documented by archaeological and genetic studies. Genetic studies point towards the Neolithic Near East as the centre of origin for Bos taurus, with some lines of evidence suggesting possible, albeit rare, genetic contributions from locally domesticated wild aurochsen across Eurasia. Inferences from these investigations have been based largely on the analysis of partial mitochondrial DNA sequences generated from modern animals, with limited sequence data from ancient aurochsen samples. Recent developments in DNA sequencing technologies, however, are affording new opportunities for the examination of genetic material retrieved from extinct species, providing new insight into their evolutionary history. Here we present DNA sequence analysis of the first complete mitochondrial genome (16,338 base pairs) from an archaeologically-verified and exceptionally-well preserved aurochs bone sample. Methodology DNA extracts were generated from an aurochs humerus bone sample recovered from a cave site located in Derbyshire, England and radiocarbon-dated to 6,738\u00b168 calibrated years before present. These extracts were prepared for both Sanger and next generation DNA sequencing technologies (Illumina Genome Analyzer). In total, 289.9 megabases (22.48%) of the post-filtered DNA sequences generated using the Illumina Genome Analyzer from this sample mapped with confidence to the bovine genome. A consensus B. primigenius mitochondrial genome sequence was constructed and was analysed alongside all available complete bovine mitochondrial genome sequences. Conclusions For all nucleotide positions where both Sanger and Illumina Genome Analyzer sequencing methods gave high-confidence calls, no discrepancies were observed. Sequence analysis reveals evidence of heteroplasmy in this sample and places this mitochondrial genome sequence securely within a previously identified aurochsen haplogroup (haplogroup P), thus providing novel insights into pre-domestic patterns of variation. The high proportion of authentic, endogenous aurochs DNA preserved in this sample bodes well for future efforts to determine the complete genome sequence of a wild ancestor of domestic cattle.", "keyphrases": ["genome", "bos primigenius", "genetic contribution"]}
{"id": "paleo.000000", "title": "A DISCUSSION AND PROPOSAL CONCERNING THE USE OF THE TERM CALCISPHERES", "abstract": "Abstract:\u2002 The terminology and grouping of spherical, calcareous microfossils of unknown biological affinity, usually referred to as calcispheres, are diffuse. The term calcispheres is inconsistently used, the morphological and taxonomical concepts are mostly ill\u2010defined and a formal definition is lacking. To resolve this issue, we propose, in analogy with the erection of the Acritarcha for organic microfossils of unknown origin, a new group called Calcitarcha, including all calcareous microfossils with a central cavity for which the biological affinities remain unknown.", "keyphrases": ["calcareous microfossil", "calcitarcha", "central cavity"]}
{"id": "10.1111/mec.12071", "title": "A coupled phylogeographical and species distribution modelling approach recovers the demographical history of a Neotropical seasonally dry forest tree species", "abstract": "We investigated here the demographical history of Tabebuia impetiginosa (Bignoniaceae) to understand the dynamics of the disjunct geographical distribution of South American seasonally dry forests (SDFs), based on coupling an ensemble approach encompassing hindcasting species distribution modelling and statistical phylogeographical analysis. We sampled 17 populations (280 individuals) in central Brazil and analysed the polymorphisms at chloroplast (trnS\u2010trnG, psbA\u2010trnH, and ycf6\u2010trnC intergenic spacers) and nuclear (ITS nrDNA) genomes. Phylogenetic analyses based on median\u2010joining network showed no haplotype sharing among population but strong evidence of incomplete lineage sorting. Coalescent analyses showed historical constant populations size, negligible gene flow among populations, and an ancient time to most recent common ancestor dated from ~4.7 \u00b1 1.1 Myr BP. Most divergences dated from the Lower Pleistocene, and no signal of important population size reduction was found in coalescent tree and tests of demographical expansion. Demographical scenarios were built based on past geographical range dynamic models, using two a priori biogeographical hypotheses (\u2018Pleistocene Arc\u2019 and \u2018Amazonian SDF expansion\u2019) and on two additional hypotheses suggested by the palaeodistribution modelling built with several algorithms for distribution modelling and palaeoclimatic data. The simulation of these demographical scenarios showed that the pattern of diversity found so far for T. impetiginosa is in consonance with a palaeodistribution expansion during the last glacial maximum (LGM, 21 kyr BP), strongly suggesting that the current disjunct distribution of T. impetiginosa in SDFs may represent a climatic relict of a once more wide distribution.", "keyphrases": ["demographical history", "dynamic", "geographical distribution", "lgm", "coalescence simulation"]}
{"id": "10.1098/rsif.2010.0634", "title": "The \u2018Goldilocks\u2019 effect: preservation bias in vertebrate track assemblages", "abstract": "Finite-element analysis was used to investigate the extent of bias in the ichnological fossil record attributable to body mass. Virtual tracks were simulated for four dinosaur taxa of different sizes (Struthiomimus, Tyrannosaurus, Brachiosaurus and Edmontosaurus), in a range of substrate conditions. Outlines of autopodia were generated based upon osteology and published soft-tissue reconstructions. Loads were applied vertically to the feet equivalent to the weight of the animal, and distributed accordingly to fore- and hindlimbs where relevant. Ideal, semi-infinite elastic\u2013plastic substrates displayed a \u2018Goldilocks\u2019 quality where only a narrow range of loads could produce tracks, given that small animals failed to indent the substrate, and larger animals would be unable to traverse the area without becoming mired. If a firm subsurface layer is assumed, a more complete assemblage is possible, though there is a strong bias towards larger, heavier animals. The depths of fossil tracks within an assemblage may indicate thicknesses of mechanically distinct substrate layers at the time of track formation, even when the lithified strata appear compositionally homogeneous. This work increases the effectiveness of using vertebrate tracks as palaeoenvironmental indicators in terms of inferring substrate conditions at the time of track formation. Additionally, simulated undertracks are examined, and it is shown that complex deformation beneath the foot may not be indicative of limb kinematics as has been previously interpreted, but instead ridges and undulations at the base of a track may be a function of sediment displacement vectors and pedal morphology.", "keyphrases": ["goldilock", "finite-element analysis", "substrate", "depth", "track formation"]}
{"id": "paleo.000585", "title": "A model for furcate septal increase in a Triassic scleractiniamorph", "abstract": "Triassic corals with septa that branch repeatedly and centripetally are here assigned to a new genus Furcophyllia. Septa of F. septafindens (Volz, 1896), re-described from the Italian Dolomites, are composed of 3-10 blades (\"septal brooms\"). Distances between adjacent septa and their branches are equal, and the thickness of all blades is approximately the same throughout ontogeny. However, none of the septal brooms show the same branching pattern. Proposed herein is a simple computer model that reproduces septal pattern, similar to that of Furcophyllia, based on a minimal set of rules: (i) uniform coverage of intra-calicular space; (ii) regular bifurcations following some probability; (iii) keeping some minimal distance between septal branches. The elaborate septal pattern of Furcophyllia suggests a distinct organization of the polyp's soft tissue, especially mesenteries whose appearance in modern corals is associated with insertion of sclerosepta. Hypothesis 1 suggests that mesenterial pairs flanked only \"septal brooms\" and that septal branches functionally corresponded with septal microarchitecture. Hypothesis 2 suggests that mesenterial pairs developed between all septal branches that functionally correspond with conventional septa. Delicate menianae, which developed on Furcophyllia septal faces (and many other Triassic corals) resemble similar septal microarchitecture of the Recent agariciid Leptoseris fragilis and may be closely related to the suspension feeding strategy of this coral. The furcate septal arrangement in Furcophyllia is unique among Triassic corals, and generally, among Mesozoic and Cenozoic corals. The only analogous corals are Cretaceous aulastraeoporids (e.g., Preverastrea, Paronastraea), Trochoidomeandra, and some Jurassic rhipidogyrids having secondary (apophysal) septal branches. In some Recent caryophylliids (Trochocyathus rhombocolumna, Phacelocyathus flos) primary septa may also split dichotomously and centripetally.", "keyphrases": ["triassic coral", "furcophyllia", "computer model"]}
{"id": "10.1126/science.1101476", "title": "Assessing the Causes of Late Pleistocene Extinctions on the Continents", "abstract": "One of the great debates about extinction is whether humans or climatic change caused the demise of the Pleistocene megafauna. Evidence from paleontology, climatology, archaeology, and ecology now supports the idea that humans contributed to extinction on some continents, but human hunting was not solely responsible for the pattern of extinction everywhere. Instead, evidence suggests that the intersection of human impacts with pronounced climatic change drove the precise timing and geography of extinction in the Northern Hemisphere. The story from the Southern Hemisphere is still unfolding. New evidence from Australia supports the view that humans helped cause extinctions there, but the correlation with climate is weak or contested. Firmer chronologies, more realistic ecological models, and regional paleoecological insights still are needed to understand details of the worldwide extinction pattern and the population dynamics of the species involved.", "keyphrases": ["climatic change", "northern hemisphere", "chronology", "lgm"]}
{"id": "10.1144/SP523-2021-73", "title": "The dire straits of Paratethys: Gateways to the anoxic giant of Eurasia", "abstract": "A complex interplay of palaeoclimatic, eustatic and tectonic processes led to fragmentation and dissipation of the vast Tethys Ocean in Eocene-Oligocene times. The resulting Paratethys Sea occupied the northern Tethys region on Eurasia, grouping water masses of various subbasins, separated from each other and from the open ocean through narrow and shallow gateways and land bridges. Changes in marine gateway configuration and intra-basinal connectivity affected the regional hydrology, shifting most Paratethyan basins to extreme carbon-sink anoxic environments, anomalohaline evaporitic or brackish conditions or even endorheic lakes. Paratethys gateway restriction triggered the onset of a long-lasting (\u223c20 Myr) giant anoxic sea, characterised by stratified water masses and anoxic bottom water conditions, resulting in thick hydrocarbon source rocks. Here, we review the geological evolution of the \u201cdire straits\u201d of Paratethys that played a crucial role in the Eocene-Oligocene connectivity history of the Central Eurasian seas and we show that the main anoxic phases (Kuma and Maikop) correspond to restricted connectivity with the global ocean and a period of CO2 depletion in the atmosphere. Paratethys represents one of the largest carbon sinks of Earth's history and may thus have played a prominent role in global climate change.", "keyphrases": ["dire strait", "configuration", "map", "palaeogeographic map"]}
{"id": "10.2478/geoca-2014-0005", "title": "Early Sarmatian paleoenvironments in the easternmost Pannonian Basin (Borod Depression, Romania) revealed by the micropaleontological data", "abstract": "Abstract The Sarmatian sedimentary record of the Borod Depression (eastern Pannonian Basin) consists of a marine sequence with continental influence. The investigated section, located near V\u00e2rciorog, was biostratigraphically and paleoenvironmentally analysed. The micro- and macrofossil assemblages include dasycladaceans, characeans, foraminifera, molluscs, polychaetes, ostracods, crabs, bryozoans, fish and vertebrate remains, which are characteristic for a shallow marine setting with local transitions to continental facies. The microfossil assemblages are characteristic for the Elphidium reginum Zone and Mohrensternia Zone of the early Sarmatian (Serravallian). The succession of populations correlates with the sedimentological trend, allowing the separation of several genetic units. The relative sea-level changes and the progradational trend from the top of the section suggest active tectonics in the hinterland (Apuseni Mountains). The shallow seas surrounding the emerging islands (Apuseni Mountains) provided the connections between the Pannonian and Transylvanian basins during the early Sarmatian", "keyphrases": ["pannonian basin", "continental influence", "foraminifera", "early sarmatian"]}
{"id": "paleo.001868", "title": "The first fossil record of Polyrhachis (Hymenoptera: Formicidae: Formicinae) from the Upper Miocene of Crete (Greece)", "abstract": "Polyrhachis annosus n. sp., based on part and counterpart of a unique ant worker specimen from Late Miocene deposits of the island of Crete (Greece), is figured and described here. Features of P. annosus unique for the large recent genus Polyrhachis include a large first gastral segment, a scapus attached at some distance from the clypeus, and an alitrunk (mesosoma) and petiole each with a pair of teeth or spines. The new taxon represents the first occurrence of the genus in the fossil record. The origin and rise of one of the world's largest and most distinct ant genera are still a puzzle, and closely related genera are quite diverse in Tertiary amber deposits. Interestingly, the abundance of Polyrhachis in Indonesian copal confirms the statement that their absence in Baltic amber is not casual.", "keyphrases": ["polyrhachis", "circum-mediterranean entomofauna", "palaeoclimate", "insect family psychodidae", "present-day distribution"]}
{"id": "10.5194/bg-9-717-2012", "title": "Latitudinal differences in the amplitude of the OAE-2 carbon isotopic excursion: p CO 2 and paleo productivity", "abstract": "Abstract. A complete, well-preserved record of the Cenomanian/Turonian (C/T) Oceanic Anoxic Event 2 (OAE-2) was recovered from Demerara Rise in the southern North Atlantic Ocean (ODP site 1260). Across this interval, we determined changes in the stable carbon isotopic composition of sulfur-bound phytane (\u03b413Cphytane), a biomarker for photosynthetic algae. The \u03b413Cphytane record shows a positive excursion at the onset of the OAE-2 interval, with an unusually large amplitude (~7\u2030) compared to existing C/T proto-North Atlantic \u03b413Cphytane records (3\u20136\u2030). Overall, the amplitude of the excursion of \u03b413Cphytane decreases with latitude. Using reconstructed sea surface temperature (SST) gradients for the proto-North Atlantic, we investigated environmental factors influencing the latitudinal \u03b413Cphytane gradient. The observed gradient is best explained by high productivity at DSDP Site 367 and Tarfaya basin before OAE-2, which changed in overall high productivity throughout the proto-North Atlantic during OAE-2. During OAE-2, productivity at site 1260 and 603B was thus more comparable to the mid-latitude sites. Using these constraints as well as the SST and \u03b413Cphytane-records from Site 1260, we subsequently reconstructed pCO2 levels across the OAE-2 interval. Accordingly, pCO2 decreased from ca. 1750 to 900 ppm during OAE-2, consistent with enhanced organic matter burial resulting in lowering pCO2. Whereas the onset of OAE-2 coincided with increased pCO2, in line with a volcanic trigger for this event, the observed cooling within OAE-2 probably resulted from CO2 sequestration in black shales outcompeting CO2 input into the atmosphere. Together these results show that the ice-free Cretaceous world was sensitive to changes in pCO2 related to perturbations of the global carbon cycle.", "keyphrases": ["carbon", "excursion", "latitude"]}
{"id": "paleo.011386", "title": "Neurocranial anatomy of an enigmatic Early Devonian fish sheds light on early osteichthyan evolution", "abstract": "The skull of \u2018Ligulalepis\u2019 from the Early Devonian of Australia (AM-F101607) has significantly expanded our knowledge of early osteichthyan anatomy, but its phylogenetic position has remained uncertain. We herein describe a second skull of \u2018Ligulalepis\u2019 and present micro-CT data on both specimens to reveal novel anatomical features, including cranial endocasts. Several features previously considered to link \u2018Ligulalepis\u2019 with actinopterygians are now considered generalized osteichthyan characters or of uncertain polarity. The presence of a lateral cranial canal is shown to be variable in its development between specimens. Other notable new features include the presence of a pineal foramen, the some detail of skull roof sutures, the shape of the nasal capsules, a placoderm-like hypophysial vein, and a chondrichthyan-like labyrinth system. New phylogenetic analyses place \u2018Ligulalepis\u2019 as a stem osteichthyan, specifically as the sister taxon to \u2018psarolepids\u2019 plus crown osteichthyans. The precise position of \u2018psarolepids\u2019 differs between parsimony and Bayesian analyses.", "keyphrases": ["anatomy", "ligulalepis", "phylogenetic position", "stem osteichthyan", "bayesian analysis"]}
{"id": "paleo.010042", "title": "Extreme Cranial Ontogeny in the Upper Cretaceous Dinosaur Pachycephalosaurus", "abstract": "Background Extended neoteny and late stage allometric growth increase morphological disparity between growth stages in at least some dinosaurs. Coupled with relatively low dinosaur density in the Upper Cretaceous of North America, ontogenetic transformational representatives are often difficult to distinguish. For example, many hadrosaurids previously reported to represent relatively small lambeosaurine species were demonstrated to be juveniles of the larger taxa. Marginocephalians (pachycephalosaurids + ceratopsids) undergo comparable and extreme cranial morphological change during ontogeny. Methodology/Principal Findings Cranial histology, morphology and computer tomography reveal patterns of internal skull development that show the purported diagnostic characters for the pachycephalosaurids Dracorex hogwartsia and Stygimoloch spinifer are ontogenetically derived features. Coronal histological sections of the frontoparietal dome of an adult Pachycephalosaurus wyomingensis reveal a dense structure composed of metaplastic bone with a variety of extremely fibrous and acellular tissue. Coronal histological sections and computer tomography of a skull and frontoparietal dome of Stygimoloch spinifer reveal an open intrafrontal suture indicative of a subadult stage of development. These dinosaurs employed metaplasia to rapidly grow and change the size and shape of their horns, cranial ornaments and frontoparietal domes, resulting in extreme cranial alterations during late stages of growth. We propose that Dracorex hogwartsia, Stygimoloch spinifer and Pachycephalosaurus wyomingensis are the same taxon and represent an ontogenetic series united by shared morphology and increasing skull length. Conclusions/Significance Dracorex hogwartsia (juvenile) and Stygimoloch spinifer (subadult) are reinterpreted as younger growth stages of Pachycephalosaurus wyomingensis (adult). This synonymy reduces the number of pachycephalosaurid taxa from the Upper Cretaceous of North America and demonstrates the importance of cranial ontogeny in evaluating dinosaur diversity and taxonomy. These growth stages reflect a continuum rather than specific developmental steps defined by \u201cknown\u201d terminal morphologies.", "keyphrases": ["pachycephalosaurus", "skull", "taxonomy"]}
{"id": "10.1029/90PA02498", "title": "Evolution of Modern Deepwater Circulation: Evidence from the Late Miocene Southern Ocean", "abstract": "Deepwater circulation plays an important role in climate modulation through its redistribution of heat and salt and its control of atmospheric CO2. Oppo and Fairbanks (1987) showed that the Southern Ocean is an excellent monitor of deepwater circulation changes for two reasons: (1) the Southern Ocean is a mixing reservoir for incoming North Atlantic Deep Water and recirculated water from the Pacific and Indian oceans; and (2) the nutrient/\u03b413C tracers of deepwater are not significantly changed by surficial processes within the Southern Ocean. We can extend these principles to the late Miocene because tectonic changes in the Oligocene and early and middle Miocene developed near-modern basinal configurations. However, on these time scales, changes in the oceanic carbon reservoir and mean ocean nutrient levels also affect the \u03b413C differences between ocean basins. From 9.8 to 9.3 Ma, Southern Ocean \u03b413C values oscillated between high North Atlantic values and low Pacific values. The Southern Ocean recorded \u03b413C values similar to Pacific values from 9.2 to 8.9 Ma, reflecting a low contribution of Northern Component Water (NCW). The \u03b413C differences between the NCW and Pacific Outflow Water (POW) end-members were low from 8.9 to 8.0 Ma, making it difficult to discern circulation patterns. NCW production may have completely shutdown at 8.6 Ma, allowing Southern Component Water (SCW) to fill the North Atlantic and causing the \u03b413C values in the North Atlantic, Pacific, and Southern oceans to converge. Deepwater \u03b413C patterns resembling the modern distributions evolved by 7.0 Ma: \u03b413C values were near 1.0\u2030 in the North Atlantic; 0.0\u2030 in the Pacific; and 0.5\u2030 in the Southern Ocean. Development of near-modern \u03b413C distributions by 7.0 Ma resulted not only from an increase in NCW flux but also from an increase in deepwater nutrient levels. Both of these processes increased the \u03b413C difference between the North Atlantic and Pacific oceans. Deepwater circulation patterns similar to today's operated as early as 9.8 Ma, but were masked by the lower nutrient/\u03b413C differences. During the late Miocene, \u201cinterglacial\u201d intervals prevailed during intervals of NCW production, while \u201cglacial\u201d intervals occurred during low NCW production.", "keyphrases": ["pacific", "middle miocene", "northern component water"]}
{"id": "10.1029/96PA00571", "title": "High\u2010resolution (104 years) deep\u2010sea foraminiferal stable isotope records of the Eocene\u2010Oligocene climate transition", "abstract": "We have constructed high-resolution (104\u2013 105 years) benthic foraminiferal \u03b413C and \u03b418O records for the upper Eocene through lower Oligocene of two pelagic sequences, Deep Sea Drilling Project (DSDP) Site 522 in the Angola Basin, South Atlantic Ocean, and Ocean Drilling Program (ODP) Site 744 in the southern Indian Ocean. These records provide improved constraints on both the timing and magnitude of marine oxygen and carbon isotope events from 30 to 35 Ma. The oxygen isotope records indicate that the ubiquitous \u03b418O increase (Oi-1), which marks the rapid expansion of continental ice sheets and a minimum of 3\u00b0 to 4\u00b0C of cooling of bottom waters in the earliest Oligocene (33.6 Ma), occurred in <350 kyr. More than half the transition occurred over the final 40\u201350 kyr. This period of lower temperatures and widespread continental glaciation persisted for roughly 400 kyr (i.e., the duration of magnetochron C13n). These records also indicate that this interval was characterized by at least two \u223c 100-kyr waxing and waning cycles (Oi-1a and Oi-1b) and possibly several higher-frequency events. The benthic foraminiferal \u03b413C records show a positive 0.8\u2030 excursion that is nearly isochronous with the Oi-1 oxygen isotope increase. Similar magnitude \u03b413C increases at other sites indicate this was a global phenomenon suggestive of an unusually large perturbation to the carbon cycle. This excursion was followed by smaller amplitude \u03b413C oscillations with periods of roughly \u223c400 kyr. We suspect that the ubiquitous Oi-1 \u03b413C excursion resulted from a brief but substantial increase in export production and carbon burial.", "keyphrases": ["continental ice sheet", "cooling", "early oligocene"]}
{"id": "paleo.001640", "title": "An Early Cambrian Fauna of Skeletal Fossils from the Emyaksin Formation, Northern Siberia", "abstract": "An assemblage of mineralised skeletal fossils containing molluscs, hyoliths, halkieriids, chancelloriids, tommotiids, lobopodians, paleoscolecids, bradoriids, echinoderms, anabaritids, hyolithelminths, hexactinnelid, and heteractinid sponges is described from the early Cambrian Emyaksin Formation exposed along the Malaya Kuonamka and Bol'shaya Kuonamka rivers, eastern flanks of the Anabar Uplift, northern Siberian Platform. The sampled succession is attributed to the Tommotian\u2014Botoman Stages of Siberia and correlated with Stage 2 of Series 1\u2014Stage 4 of Series 2 of the IUGS chronostratigraphical scheme for the Cambrian. Carbon isotope chemostratigraphy is applied herein for regional correlation. The fauna contains the earliest Siberian and probably global first appearances of lobopodians, paleoscolecids, and echinoderms, and includes elements in common with coeval faunas from Gondwana, Laurentia, and Baltica. For the first time from Siberia, the latest occurrence of anabaritids is documented herein from the Atdabanian Stage. Problematic calcium phosphatic sclerites of Fengzuella zhejiangensis have not been previously known from outside China. The sellate sclerites, Camenella garbowskae and mitral sclerites, C. kozlowskii are unified within one species, C. garbowskae. In addition to more common slender sclerites, Rhombocorniculum insolutum include broad calcium phosphatic sclerites. A number of fossils described herein demonstrate excellent preservation of fine details of skeletal microstructures. Based on new microstructural data, sclerites of Rhombocorniculum are interpreted as chaetae of the type occurring in annelids. A new mollusc Enigmaconus? pyramidalis Kouchinsky and Vendrasco sp. nov. and a hyolith Triplicatella papilio Kouchinsky sp. nov. are described.", "keyphrases": ["emyaksin formation", "lobopodian", "sclerite"]}
{"id": "paleo.012683", "title": "Osedax borings in fossil marine bird bones", "abstract": "The bone-eating marine annelid Osedax consumes mainly whale bones on the deep-sea floor, but recent colonization experiments with cow bones and molecular age estimates suggesting a possible Cretaceous origin of Osedax indicate that this worm might be able grow on a wider range of substrates. The suggested Cretaceous origin was thought to imply that Osedax could colonize marine reptile or fish bones, but there is currently no evidence that Osedax consumes bones other than those of mammals. We provide the first evidence that Osedax was, and most likely still is, able to consume non-mammalian bones, namely bird bones. Borings resembling those produced by living Osedax were found in bones of early Oligocene marine flightless diving birds (family Plotopteridae). The species that produced these boreholes had a branching filiform root that grew to a length of at least 3 mm, and lived in densities of up to 40 individuals per square centimeter. The inclusion of bird bones into the diet of Osedax has interesting implications for the recent suggestion of a Cretaceous origin of this worm because marine birds have existed continuously since the Cretaceous. Bird bones could have enabled this worm to survive times in the Earth\u2019s history when large marine vertebrates other than fish were rare, specifically after the disappearance of large marine reptiles at the end-Cretaceous mass extinction event and before the rise of whales in the Eocene.", "keyphrases": ["bird bone", "substrate", "osedax"]}
{"id": "paleo.010665", "title": "Tooth crown tissue proportions and enamel thickness in Early Pleistocene Homo antecessor molars (Atapuerca, Spain)", "abstract": "Tooth crown tissue proportions and enamel thickness distribution are considered reliable characters for inferring taxonomic identity, phylogenetic relationships, dietary and behavioural adaptations in fossil and extant hominids. While most Pleistocene hominins display variations from thick to hyper-thick enamel, Neanderthals exhibit relatively thinner. However, the chronological and geographical origin for the appearance of this typical Neanderthal condition is still unknown. The European late Early Pleistocene species Homo antecessor (Gran Dolina-TD6 site, Sierra de Atapuerca) represents an opportunity to investigate the appearance of the thin condition in the fossil record. In this study, we aim to test the hypothesis if H. antecessor molars approximates the Neanderthal condition for tissue proportions and enamel thickness. To do so, for the first time we characterised the molar inner structural organization in this Early Pleistocene hominin taxon (n = 17) and compared it to extinct and extant populations of the genus Homo from African, Asian and European origin (n = 355). The comparative sample includes maxillary and mandibular molars belonging to H. erectus, East and North African Homo, European Middle Pleistocene Homo, Neanderthals, and fossil and extant H. sapiens. We used high-resolution images to investigate the endostructural configuration of TD6 molars (tissue proportions, enamel thickness and distribution). TD6 permanent molars tend to exhibit on average thick absolute and relative enamel in 2D and 3D estimates, both in the complete crown and the lateral enamel. This condition is shared with the majority of extinct and extant hominin sample, except for Neanderthals and some isolated specimens. However, while the total crown percentage of dentine in TD6 globally resembles the low modern values, the lateral crown percentage of dentine tends to be much higher, closer to the Neanderthal signal. Similarly, the H. antecessor molar enamel distribution maps reveal a relative distribution pattern that is more similar to the Neanderthal condition (with the thickest enamel more spread at the periphery of the occlusal basin) rather than that of other fossil specimens and modern humans (with thicker cuspal enamel). Future studies on European Middle Pleistocene populations will provide more insights into the evolutionary trajectory of the typical Neanderthal dental structural organization.", "keyphrases": ["crown", "lateral enamel", "dentine"]}
{"id": "paleo.012773", "title": "Pleistocene footprints show intensive use of lake margin habitats by Homo erectus groups", "abstract": "Reconstructing hominin paleoecology is critical for understanding our ancestors\u2019 diets, social organizations and interactions with other animals. Most paleoecological models lack fine-scale resolution due to fossil hominin scarcity and the time-averaged accumulation of faunal assemblages. Here we present data from 481 fossil tracks from northwestern Kenya, including 97 hominin footprints attributed to Homo erectus. These tracks are found in multiple sedimentary layers spanning approximately 20 thousand years. Taphonomic experiments show that each of these trackways represents minutes to no more than a few days in the lives of the individuals moving across these paleolandscapes. The geology and associated vertebrate fauna place these tracks in a deltaic setting, near a lakeshore bordered by open grasslands. Hominin footprints are disproportionately abundant in this lake margin environment, relative to hominin skeletal fossil frequency in the same deposits. Accounting for preservation bias, this abundance of hominin footprints indicates repeated use of lakeshore habitats by Homo erectus. Clusters of very large prints moving in the same direction further suggest these hominins traversed this lakeshore in multi-male groups. Such reliance on near water environments, and possibly aquatic-linked foods, may have influenced hominin foraging behavior and migratory routes across and out of Africa.", "keyphrases": ["footprint", "other animal", "fossil track", "kenya", "taphonomic experiment"]}
{"id": "10.3374/014.052.0102", "title": "The Bipedal Stem Crocodilian Poposaurus gracilis: Inferring Function in Fossils and Innovation in Archosaur Locomotion", "abstract": "ABSTRACT \n We introduce a spectacular new specimen of a Late Triassic stem crocodilian identified as Poposaurus gracilis. It is part of a poorly known group, Poposauroidea, that, because of its striking similarities with contemporaneous stem avians (\u201cdinosaurs\u201d), has long puzzled archosaur paleontologists. Observed vertebrate locomotor behaviors, together with exceptional preservation of distinctive anatomical clues in this fossil, enable us to examine locomotor evolution in light of new advances in phylogenetic relationships among Triassic archosaurs. Because this stem crocodilian is unambiguously an archosaur, a diapsid, a tetrapod and a choanate sarcopterygian, we can safely infer major components of its locomotor behavior. These inferences, together with form-function constraints, suggest that P. gracilis was a fleet-footed, obligately erect-postured, striding biped. That behavior seems to have been superimposed on the ancestral archosaur's innovative locomotor repertoire, which includes the capacity to \u201chigh walk.\u201d These novelties persist in a recognizable form in archosaurs for at least 245 million years and are widely distributed across Earth's surface in diverse ecological settings. They thus qualify as evolutionary innovations regardless of significant differences in diversification rates among extant diapsid reptiles.", "keyphrases": ["archosaur", "archosauromorph taxa", "gracile"]}
{"id": "paleo.003007", "title": "Function and Evolution of Ankylosaur Dermal Armor", "abstract": "Ankylosaurs have spike-, plate-, and club-shaped osteoderms probably used as defensive and/or offensive weapons. Previous studies have proposed the evolution and function of small ankylosaur osteoderms, but histological variations in their defensive weapons are little known. Here, we provide comparisons of the internal structures in defensive weapons of ankylosaurs, which shed light on understanding their evolutionary history and function. Histological features of spikes, plates, and clubs are similar to those of small osteoderms in having thin compact bone, thick cancellous bone with large vascular canals, and abundant collagen fibers. A previous study demonstrated that each of the three groups of ankylosaurs (the Polacanthidae, Nodosauridae, and Ankylosauridae) have distinct arrangements of collagen fibers in small osteoderms. This study shows that spikes and clubs of ankylosaurs maintain the same characteristic features for each group despite the differences in shapes and sizes. These histological similarities suggest that various types of osteoderms in ankylosaurs retained the thin compact bone and abundant fiber structures of the small osteoderms during their evolution. Polacanthid spikes show thin compact bone, with less collagen fibers than in spikes of nodosaurids and spikes and clubs of ankylosaurids. Also, ankylosaurid plates with hollow bases are very thin in morphology and show thin compact bone. These results imply that the bone strengths of polacanthid spikes and ankylosaurid plates are lower than spikes and clubs of other ankylosaurs, indicating that they may be used more probably as display and/or thermoregulation rather than as weapons. It is thus probable that ankylosaur armor in general played more than just a defensive role.", "keyphrases": ["ankylosaur", "osteoderm", "arrangement", "nodosaurid"]}
{"id": "10.1111/1475-4983.00189", "title": "Body Mass Estimates in Extinct Mammals from Limb Bone Dimensions: the Case of North American Hyaenodontids", "abstract": "The body mass estimation of several limb bone dimensions (shaft cross\u2010sectional properties, articular sizes, and bone lengths) were examined using bivariate linear regression analyses. The sample included taxonomically and behaviourally diverse small to medium\u2010sized Recent carnivorans and carnivorous marsupials. All examined limb bone dimensions indicated low errors (percentage standard error of estimate, 8\u201313) for the body mass estimations. Among them, humeral and femoral shaft properties correlated best with body weight, while limb bone lengths gave larger errors. Both humeral and femoral head dimensions have relatively large individual variations, and distal humeral articular dimensions seem to be influenced more by phylogenetic differences. The regressions based on each locomotor group gave slightly lower errors than those based on the total pooled sample. The results were then applied to hyaenodontid creodonts from the Eocene\u2013Oligocene of North America. The estimated body masses (kg) are: Arfia, 5.4\u20139.5; Prototomus, <6.0; Pyrocyon, 2.6; Sinopa, 1.3\u20131.4; Tritemnodon, 7.6\u201313; Prolimnocyon, 1.6; Thinocyon, 0.7\u20132.5; Machaeroides, 12; Limnocyon, 7.8\u2013 16; Hyaenodon, 9.1\u201343. The various limb bone dimensions give different body mass values, but the variation in estimates is smaller compared to those derived from dental or cranial measurements.", "keyphrases": ["standard error", "articular dimension", "body mass"]}
{"id": "paleo.009847", "title": "Comprehensive analysis of microorganisms accompanying human archaeological remains", "abstract": "Abstract Metagenome analysis has become a common source of information about microbial communities that occupy a wide range of niches, including archaeological specimens. It has been shown that the vast majority of DNA extracted from ancient samples come from bacteria (presumably modern contaminants). However, characterization of microbial DNA accompanying human remains has never been done systematically for a wide range of different samples. We used metagenomic approaches to perform comparative analyses of microorganism communities present in 161 archaeological human remains. DNA samples were isolated from the teeth of human skeletons dated from 100 AD to 1200 AD. The skeletons were collected from 7 archaeological sites in Central Europe and stored under different conditions. The majority of identified microbes were ubiquitous environmental bacteria that most likely contaminated the host remains not long ago. We observed that the composition of microbial communities was sample-specific and not correlated with its temporal or geographical origin. Additionally, traces of bacteria and archaea typical for human oral/gut flora, as well as potential pathogens, were identified in two-thirds of the samples. The genetic material of human-related species, in contrast to the environmental species that accounted for the majority of identified bacteria, displayed DNA damage patterns comparable with endogenous human ancient DNA, which suggested that these microbes might have accompanied the individual before death. Our study showed that the microbiome observed in an individual sample is not reliant on the method or duration of sample storage. Moreover, shallow sequencing of DNA extracted from ancient specimens and subsequent bioinformatics analysis allowed both the identification of ancient microbial species, including potential pathogens, and their differentiation from contemporary species that colonized human remains more recently.", "keyphrases": ["microbial community", "dna", "ancient sample", "human remain", "pathogen"]}
{"id": "10.1098/rsbl.2020.0005", "title": "Identifying drivers of forest resilience in long-term records from the Neotropics", "abstract": "Here, we use 30 long-term, high-resolution palaeoecological records from Mexico, Central and South America to address two hypotheses regarding possible drivers of resilience in tropical forests as measured in terms of recovery rates from previous disturbances. First, we hypothesize that faster recovery rates are associated with regions of higher biodiversity, as suggested by the insurance hypothesis. And second, that resilience is due to intrinsic abiotic factors that are location specific, thus regions presently displaying resilience in terms of persistence to current climatic disturbances should also show higher recovery rates in the past. To test these hypotheses, we applied a threshold approach to identify past disturbances to forests within each sequence. We then compared the recovery rates to these events with pollen richness before the event. We also compared recovery rates of each site with a measure of present resilience in the region as demonstrated by measuring global vegetation persistence to climatic perturbations using satellite imagery. Preliminary results indeed show a positive relationship between pre-disturbance taxonomic richness and faster recovery rates. However, there is less evidence to support the concept that resilience is intrinsic to a region; patterns of resilience apparent in ecosystems presently are not necessarily conservative through time.", "keyphrases": ["long-term", "high-resolution palaeoecological record", "south america", "recovery rate", "ecosystem"]}
{"id": "paleo.009118", "title": "An Analytical Approach for Estimating Fossil Record and Diversification Events in Sharks, Skates and Rays", "abstract": "Background Modern selachians and their supposed sister group (hybodont sharks) have a long and successful evolutionary history. Yet, although selachian remains are considered relatively common in the fossil record in comparison with other marine vertebrates, little is known about the quality of their fossil record. Similarly, only a few works based on specific time intervals have attempted to identify major events that marked the evolutionary history of this group. Methodology/Principal Findings Phylogenetic hypotheses concerning modern selachians\u2019 interrelationships are numerous but differ significantly and no consensus has been found. The aim of the present study is to take advantage of the range of recent phylogenetic hypotheses in order to assess the fit of the selachian fossil record to phylogenies, according to two different branching methods. Compilation of these data allowed the inference of an estimated range of diversity through time and evolutionary events that marked this group over the past 300 Ma are identified. Results indicate that with the exception of high taxonomic ranks (orders), the selachian fossil record is by far imperfect, particularly for generic and post-Triassic data. Timing and amplitude of the various identified events that marked the selachian evolutionary history are discussed. Conclusion/Significance Some identified diversity events were mentioned in previous works using alternative methods (Early Jurassic, mid-Cretaceous, K/T boundary and late Paleogene diversity drops), thus reinforcing the efficiency of the methodology presented here in inferring evolutionary events. Other events (Permian/Triassic, Early and Late Cretaceous diversifications; Triassic/Jurassic extinction) are newly identified. Relationships between these events and paleoenvironmental characteristics and other groups\u2019 evolutionary history are proposed.", "keyphrases": ["evolutionary history", "time interval", "selachian fossil record", "taxonomic rank", "early jurassic"]}
{"id": "paleo.000553", "title": "Pheomelanin pigment remnants mapped in fossils of an extinct mammal", "abstract": "Recent progress has been made in paleontology with respect to resolving pigmentation in fossil material. Morphological identification of fossilized melanosomes has been one approach, while a second methodology using chemical imaging and spectroscopy has also provided critical information particularly concerning eumelanin (black pigment) residue. In this work we develop the chemical imaging methodology to show that organosulfur-Zn complexes are indicators of pheomelanin (red pigment) in extant and fossil soft tissue and that the mapping of these residual biochemical compounds can be used to restore melanin pigment distribution in a 3 million year old extinct mammal species (Apodemus atavus). Synchotron Rapid Scanning X-ray Fluorescence imaging showed that the distributions of Zn and organic S are correlated within this fossil fur just as in pheomelanin-rich modern integument. Furthermore, Zn coordination chemistry within this fossil fur is closely comparable to that determined from pheomelanin-rich fur and hair standards. The non-destructive methods presented here provide a protocol for detecting residual pheomelanin in precious specimens.", "keyphrases": ["melanosome", "eumelanin", "tissue", "pheomelanin", "fossil mouse apodemus"]}
{"id": "paleo.006599", "title": "New data on the Paleocene monotreme Monotrematum sudamericanum, and the convergent evolution of triangulate molars", "abstract": "We describe an additional fragmentary upper molar and the first lower molar known of Monotrematum sudamericanum, the oldest Cenozoic (Paleocene) monotreme. Comparisons suggest that the monotreme evolution passed through a stage in which their molars were \"pseudo-triangulate\", without a true trigonid, and that the monotreme pseudo-triangulate pattern did not arise through rotation of the primary molar cusps. Monotreme lower molars lack a talonid, and consequently there is no basin with facets produced by the wearing action of a \"protocone\"; a cristid obliqua connecting the \"talonid\" to the \"trigonid\" is also absent. We hypothesize that acquisition of the molar pattern seen in Steropodon galmani (Early Cretaceous, Albian) followed a process similar to that already postulated for docodonts (Docodon in Laurasia, Reigitherium in the South American sector of Gondwana) and, probably, in the gondwanathere Ferugliotherium.", "keyphrases": ["monotrematum sudamericanum", "trigonid", "steropodon galmani", "low molar"]}
{"id": "paleo.010166", "title": "The genetic prehistory of the Baltic Sea region", "abstract": "While the series of events that shaped the transition between foraging societies and food producers are well described for Central and Southern Europe, genetic evidence from Northern Europe surrounding the Baltic Sea is still sparse. Here, we report genome-wide DNA data from 38 ancient North Europeans ranging from ~9500 to 2200 years before present. Our analysis provides genetic evidence that hunter-gatherers settled Scandinavia via two routes. We reveal that the first Scandinavian farmers derive their ancestry from Anatolia 1000 years earlier than previously demonstrated. The range of Mesolithic Western hunter-gatherers extended to the east of the Baltic Sea, where these populations persisted without gene-flow from Central European farmers during the Early and Middle Neolithic. The arrival of steppe pastoralists in the Late Neolithic introduced a major shift in economy and mediated the spread of a new ancestry associated with the Corded Ware Complex in Northern Europe.", "keyphrases": ["baltic sea", "scandinavia", "east"]}
{"id": "10.5710/AMGH.19.03.2018.3171", "title": "High Resolution Trilobite Biostratigraphy for the Early Late Tremadocian (Tr2) Interval (Early Ordovician) Santa Rosita Formation, Argentine Cordillera Oriental", "abstract": "Abstract. The early late Tremadocian (Tr2) interval is exceptionally well-represented in eastern areas of the Argentine Cordillera Oriental. New field collections and detailed taxonomic reassessments, as well as a reevaluation of regional data, permit the development of a highly resolved trilobite-based biostratigraphic framework. The concept of the traditional Bienvillia tetragonalis biozone is emended and the new Asaphellus nazarenensis biozone is proposed. Hence, the Tr2 interval encompasses a succession of four trilobite biozones including in ascending order the Kainella teiichii, the Bienvillia tetragonalis, the Asaphellus nazarenensis, and the Notopeltis orthometopa biozones. This resolution is notably higher than that provided by biostratigraphically significant groups such as graptolites and conodonts, and allows a detailed basinwide correlation. New taxonomic information on A. nazarenensis Tortello and Esteban and N. orthometopa (Harrington), is provided and the new species Asaphellus albae sp. nov. is defined. Detailed correlation of the trilobite fauna from the Tr2 interval with that of other paleocontinents is difficult. Taxa are mostly endemic or display wide geographic distributions but with long stratigraphic ranges. Overall, both trilobite-based and indirect international correlations highlight that this interval is hardly recognized, incompletely preserved, or the trilobite fauna is poorly known in most areas of Gondwana. Consequently, due to the completeness of the stratigraphic and fossil records of the Tr2 in the Cordillera Oriental, this region represents a global reference site for the study of this interval.", "keyphrases": ["argentine cordillera oriental", "succession", "graptolite"]}
{"id": "paleo.007780", "title": "Pedal Claw Curvature in Birds, Lizards and Mesozoic Dinosaurs \u2013 Complicated Categories and Compensating for Mass-Specific and Phylogenetic Control", "abstract": "Pedal claw geometry can be used to predict behaviour in extant tetrapods and has frequently been used as an indicator of lifestyle and ecology in Mesozoic birds and other fossil reptiles, sometimes without acknowledgement of the caveat that data from other aspects of morphology and proportions also need to be considered. Variation in styles of measurement (both inner and outer claw curvature angles) has made it difficult to compare results across studies, as have over-simplified ecological categories. We sought to increase sample size in a new analysis devised to test claw geometry against ecological niche. We found that taxa from different behavioural categories overlapped extensively in claw geometry. Whilst most taxa plotted as predicted, some fossil taxa were recovered in unexpected positions. Inner and outer claw curvatures were statistically correlated, and both correlated with relative claw robusticity (mid-point claw height). We corrected for mass and phylogeny, as both likely influence claw morphology. We conclude that there is no strong mass-specific effect on claw curvature; furthermore, correlations between claw geometry and behaviour are consistent across disparate clades. By using independent contrasts to correct for phylogeny, we found little significant relationship between claw geometry and behaviour. \u2018Ground-dweller\u2019 claws are less curved and relatively dorsoventrally deep relative to those of other behavioural categories; beyond this it is difficult to assign an explicit category to a claw based purely on geometry.", "keyphrases": ["curvature", "lifestyle", "ecology", "fossil taxa"]}
{"id": "paleo.010062", "title": "Exceptionally Preserved Jellyfishes from the Middle Cambrian", "abstract": "Cnidarians represent an early diverging animal group and thus insight into their origin and diversification is key to understanding metazoan evolution. Further, cnidarian jellyfish comprise an important component of modern marine planktonic ecosystems. Here we report on exceptionally preserved cnidarian jellyfish fossils from the Middle Cambrian (\u223c505 million years old) Marjum Formation of Utah. These are the first described Cambrian jellyfish fossils to display exquisite preservation of soft part anatomy including detailed features of structures interpreted as trailing tentacles and subumbrellar and exumbrellar surfaces. If the interpretation of these preserved characters is correct, their presence is diagnostic of modern jellyfish taxa. These new discoveries may provide insight into the scope of cnidarian diversity shortly after the Cambrian radiation, and would reinforce the notion that important taxonomic components of the modern planktonic realm were in place by the Cambrian period.", "keyphrases": ["middle cambrian", "diversification", "utah", "tentacle"]}
{"id": "paleo.002457", "title": "Armored kinorhynch-like scalidophoran animals from the early Cambrian", "abstract": "Morphology-based phylogenetic analyses support the monophyly of the Scalidophora (Kinorhyncha, Loricifera, Priapulida) and Nematoida (Nematoda, Nematomorpha), together constituting the monophyletic Cycloneuralia that is the sister group of the Panarthropoda. Kinorhynchs are unique among living cycloneuralians in having a segmented body with repeated cuticular plates, longitudinal muscles, dorsoventral muscles, and ganglia. Molecular clock estimates suggest that kinorhynchs may have diverged in the Ediacaran Period. Remarkably, no kinorhynch fossils have been discovered, in sharp contrast to priapulids and loriciferans that are represented by numerous Cambrian fossils. Here we describe several early Cambrian (~535 million years old) kinorhynch-like fossils, including the new species Eokinorhynchus rarus and two unnamed but related forms. E. rarus has characteristic scalidophoran features, including an introvert with pentaradially arranged hollow scalids. Its trunk bears at least 20 annuli each consisting of numerous small rectangular plates, and is armored with five pairs of large and bilaterally placed sclerites. Its trunk annuli are reminiscent of the epidermis segments of kinorhynchs. A phylogenetic analysis resolves E. rarus as a stem-group kinorhynch. Thus, the fossil record confirms that all three scalidophoran phyla diverged no later than the Cambrian Period.", "keyphrases": ["kinorhyncha", "loricifera", "priapulida", "sclerite"]}
{"id": "paleo.012029", "title": "Dinosaur bonebed amber from an original swamp forest soil", "abstract": "Dinosaur bonebeds with amber content, yet scarce, offer a superior wealth and quality of data on ancient terrestrial ecosystems. However, the preserved palaeodiversity and/or taphonomic characteristics of these exceptional localities had hitherto limited their palaeobiological potential. Here, we describe the amber from the Lower Cretaceous dinosaur bonebed of Ari\u00f1o (Teruel, Spain) using a multidisciplinary approach. Amber is found in both a root layer with amber strictly in situ and a litter layer mainly composed of aerial pieces unusually rich in bioinclusions, encompassing 11 insect orders, arachnids, and a few plant and vertebrate remains, including a feather. Additional palaeontological data\u2014charophytes, palynomorphs, ostracods\u2014 are provided. Ari\u00f1o arguably represents the most prolific and palaeobiologically diverse locality in which fossiliferous amber and a dinosaur bonebed have been found in association, and the only one known where the vast majority of the palaeontological assemblage suffered no or low-grade pre-burial transport. This has unlocked unprecedentedly complete and reliable palaeoecological data out of two complementary windows of preservation\u2014the bonebed and the amber\u2014from the same site.", "keyphrases": ["amber", "charophyte", "amber-bearing outcrop", "maestrazgo basin", "escucha formation"]}
{"id": "10.1126/science.1171155", "title": "Bone Assemblages Track Animal Community Structure over 40 Years in an African Savanna Ecosystem", "abstract": "Death Mirrors Life The accuracy with which fossil assemblages represent the actual composition of ancient ecological communities is very often uncertain. One way to assess the degree of fidelity between living and dead assemblages is to patiently compare modern living communities and the records they leave behind them in real time. Western and Behrensmeyer (p. 1061) recorded the composition of vertebrate herbivore communities in the Amboseli reserve in Kenya over four decades and compared this to the assemblages of bones left behind as the animals died. The results suggest a high level of fidelity of life-to-death assemblages, both in the composition and the relative abundance of species. Thus, older fossil assemblages might indeed give a reliable picture of past and extinct communities. Species abundances in African mammal bone assemblages show promise for reconstructing modern and ancient community structures. Reconstructing ancient communities depends on how accurately fossil assemblages retain information about living populations. We report a high level of fidelity between modern bone assemblages and living populations based on a 40-year study of the Amboseli ecosystem in southern Kenya. Relative abundance of 15 herbivorous species recorded in the bone assemblage accurately tracks the living populations through major changes in community composition and habitat over intervals as short as 5 years. The aggregated bone sample provides an accurate record of community structure time-averaged over four decades. These results lay the groundwork for integrating paleobiological and contemporary ecological studies across evolutionary and ecological time scales. Bone surveys also provide a useful method of assessing population changes and community structure for modern vertebrates.", "keyphrases": ["fidelity", "behrensmeyer", "vertebrate", "living population", "bone assemblage"]}
{"id": "paleo.000153", "title": "NEW INFORMATION ON THE UPPER TRIASSIC ARCHOSAURIFORM VANCLEAVEA CAMPI BASED ON NEW MATERIAL FROM THE CHINLE FORMATION OF ARIZONA", "abstract": "Two new partial skeletons from the Petrified Forest Member (Chinle Formation) of Petrified Forest National Park are referable to Vancleavea campi Long and Murry 1995. Although lacking good skull material, the new specimens possess postcranial elements that are either absent or poorly preserved in the holotype specimen. A phylogenetic analysis tentatively suggests that Vancleavea campi represents a basal archosauriform more derived than Erythrosuchus, Proterosuchus, and possibly Euparkeria. Comparisons with undescribed material from the Chinle Formation near St. Johns, Arizona, and Ghost Ranch, New Mexico, are needed to confirm this placement and also to determine the taxonomic validity of the genus Vancleavea.", "keyphrases": ["vancleavea campi", "chinle formation", "phylogenetic analysis", "archosauria"]}
{"id": "10.1126/science.1059199", "title": "Historical Overfishing and the Recent Collapse of Coastal Ecosystems", "abstract": "Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.", "keyphrases": ["pollution", "climate change", "onset"]}
{"id": "paleo.011303", "title": "Reidentification of Avian Embryonic Remains from the Cretaceous of Mongolia", "abstract": "Embryonic remains within a small (4.75 by 2.23 cm) egg from the Late Cretaceous, Mongolia are here re-described. High-resolution X-ray computed tomography (HRCT) was used to digitally prepare and describe the enclosed embryonic bones. The egg, IGM (Mongolian Institute for Geology, Ulaanbaatar) 100/2010, with a three-part shell microstructure, was originally assigned to Neoceratopsia implying extensive homoplasy among eggshell characters across Dinosauria. Re-examination finds the forelimb significantly longer than the hindlimbs, proportions suggesting an avian identification. Additional, postcranial apomorphies (strut-like coracoid, cranially located humeral condyles, olecranon fossa, slender radius relative to the ulna, trochanteric crest on the femur, and ulna longer than the humerus) identify the embryo as avian. Presence of a dorsal coracoid fossa and a craniocaudally compressed distal humerus with a strongly angled distal margin support a diagnosis of IGM 100/2010 as an enantiornithine. Re-identification eliminates the implied homoplasy of this tri-laminate eggshell structure, and instead associates enantiornithine birds with eggshell microstructure composed of a mammillary, squamatic, and external zones. Posture of the embryo follows that of other theropods with fore- and hindlimbs folded parallel to the vertebral column and the elbow pointing caudally just dorsal to the knees. The size of the egg and embryo of IGM 100/2010 is similar to the two other Mongolian enantiornithine eggs. Well-ossified skeletons, as in this specimen, characterize all known enantiornithine embryos suggesting precocial hatchlings, comparing closely to late stage embryos of modern precocial birds that are both flight- and run-capable upon hatching. Extensive ossification in enantiornithine embryos may contribute to their relatively abundant representation in the fossil record. Neoceratopsian eggs remain unrecognized in the fossil record.", "keyphrases": ["embryo", "theropod", "hatchling"]}
{"id": "10.1146/annurev-ecolsys-012021-035131", "title": "Biotic and Abiotic Controls on the Phanerozoic History of Marine Animal Biodiversity", "abstract": "During the past 541 million years, marine animals underwent three intervals of diversification (early Cambrian, Ordovician, Cretaceous\u2013Cenozoic) separated by nondirectional fluctuation, suggesting diversity-dependent dynamics with the equilibrium diversity shifting through time. Changes in factors such as shallow-marine habitat area and climate appear to have modulated the nondirectional fluctuations. Directional increases in diversity are best explained by evolutionary innovations in marine animals and primary producers coupled with stepwise increases in the availability of food and oxygen. Increasing intensity of biotic interactions such as predation and disturbance may have led to positive feedbacks on diversification as ecosystems became more complex. Important areas for further research include improving the geographic coverage and temporal resolution of paleontological data sets, as well as deepening our understanding of Earth system evolution and the physiological and ecological traits that modulated organismal responses to environmental change. Expected final online publication date for the Annual Review of Ecology, Evolution, and Systematics, Volume 52 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.", "keyphrases": ["habitat area", "evolutionary innovation", "biotic interaction", "predation"]}
{"id": "paleo.012991", "title": "Oxygen as a Driver of Early Arthropod Micro-Benthos Evolution", "abstract": "Background We examine the physiological and lifestyle adaptations which facilitated the emergence of ostracods as the numerically dominant Phanerozoic bivalve arthropod micro-benthos. Methodology/Principal Findings The PO2 of modern normoxic seawater is 21 kPa (air-equilibrated water), a level that would cause cellular damage if found in the tissues of ostracods and much other marine fauna. The PO2 of most aquatic breathers at the cellular level is much lower, between 1 and 3 kPa. Ostracods avoid oxygen toxicity by migrating to waters which are hypoxic, or by developing metabolisms which generate high consumption of O2. Interrogation of the Cambrian record of bivalve arthropod micro-benthos suggests a strong control on ecosystem evolution exerted by changing seawater O2 levels. The PO2 of air-equilibrated Cambrian-seawater is predicted to have varied between 10 and 30 kPa. Three groups of marine shelf-dwelling bivalve arthropods adopted different responses to Cambrian seawater O2. Bradoriida evolved cardiovascular systems that favoured colonization of oxygenated marine waters. Their biodiversity declined during intervals associated with black shale deposition and marine shelf anoxia and their diversity may also have been curtailed by elevated late Cambrian (Furongian) oxygen-levels that increased the PO2 gradient between seawater and bradoriid tissues. Phosphatocopida responded to Cambrian anoxia differently, reaching their peak during widespread seabed dysoxia of the SPICE event. They lacked a cardiovascular system and appear to have been adapted to seawater hypoxia. As latest Cambrian marine shelf waters became well oxygenated, phosphatocopids went extinct. Changing seawater oxygen-levels and the demise of much of the seabed bradoriid micro-benthos favoured a third group of arthropod micro-benthos, the ostracods. These animals adopted lifestyles that made them tolerant of changes in seawater O2. Ostracods became the numerically dominant arthropod micro-benthos of the Phanerozoic. Conclusions/Significance Our work has implications from an evolutionary context for understanding how oxygen-level in marine ecosystems drives behaviour.", "keyphrases": ["seawater hypoxia", "phosphatocopid", "environment"]}
{"id": "10.1111/j.1095-8339.1979.tb01511.x", "title": "Plant\u2010geography of east Malesia", "abstract": "A floristic analysis is given of the flora of the Lesser Sunda Islands. It is concluded that their flora must formerly have been richer, especially in rain-forest plants Irom both east and west Malesia. Impoverishment of the flora started at the onset of the Glacial Age, when these islands acted as an important bridge from continental south east Asia through the Philippines, Celebes, to north Australia, facilitating exchange of drought-indifferent or seasonal drought-requiring plants between Asia and Australia. Before the Pliocene the Lesser Sunda Islands contributed little to effective contact and exchange. \n \n \n \nTwo main contacts between the Malesian and Australian floras must have occurred, the first in the Upper Cretaceous to Paleocene, or even earlier, and the second, and final, contact before the end of the Miocene. These contacts were interrupted by a long period, throughout which the Australian flora was isolated. \n \n \n \nDuring the first contact Fagoideae and several other taxa of the Laurasian flora attained a bipolar-Antarctic range. Other Laurasian elements, which became thoroughly integrated with the primitive Australian-Gondwanean flora and subsequently evolved with it, probably exist but are difficult to trace. \n \n \n \nIn the Miocene, a further, more abundant influx of the Asian/Malesian element into the Australian flora took place. This influx is more easily traced in the present Australian flora, especially its tropical moiety, a number of endemic species evolving from such immigrant taxa. \n \n \n \nThe New Guinean tract had a rather poor archipelagic Australian-Gondwanean flora from the Oligocene until the Miocene, when this a.chipelago gradually became continuous land. With the developing orogeny over its whole length, it became a colossal expanse, with congenial soils and climate. The diversity of niches thus created allowed an explosive development of the Malesian element. Of the ancient Australian-Gondwanean element already present, part possibly became extinct, while part became integrated. \n \n \n \nThe reciprocal emigration of the Australian element was always impeded because of its adaptation to nutrient-deficient soil types. Such soils are very scarce in New Guinea, Malesia and south-east Asia generally. \n \n \n \nAs a result of this study, the relation between scleromorphy and nutrient-deficient soil types in Australia and South Africa has been reappraised. Scleromorphy can be traced in the tropical rainforest and is exemplarily expressed in the heath forest of west Borneo, and adjacent Banka and Billiton. It is deduced that scleromorphy is bound to soil, not to climate. \n \n \n \nThe poor flora of the primitiae of the New Guinean flora is the result of the dearth of nutrient-\u201cdelicient soils and the later competition from the Malesian rain-forest. It also accounts for the proportionally good representation of the Australian element in the mountain flora of New Guinea and other Malesian islands. \n \n \n \nThese botanical interpretations and deductions are in accord with recent tentative geophysical maps and datings. \n \n \n \nSeveral hitherto obscure facts are logically explained by this hypothesis: the overwhelming Malesian element of the present New Guinean flora; its explosive development in that island since the Miocene; the presence of the important demarcation between the Asian/Malesian and Australian element in the Torres Strait; the very low percentage of the Australian element in the Malesian flora, and the presence of various Laurasian representatives of different antiquity in the Australian flora.", "keyphrases": ["asia", "exchange", "malesian flora"]}
{"id": "10.1111/j.1502-3931.1975.tb01311.x", "title": "Biology of the Hyolitha", "abstract": "Hyoliths are Paleozoic fossils that have a calcareous exoskeleton consisting of an elongate, usually bilaterally symmetrical cone, a close fitting operculum, and a pair of curved appendages. Their skeletal ultrastructure resembles the crossed-lamellar shell layers of some molluscs. Several specimens from the Ordovician of France and the Cambrian of Antarctica have parts of the gut preserved by infilling matrix, showing that both mouth ad anus were located near the cone aperture. Muscle scars in other hyolith shells indicate that the animal had a series of dorsoventral and longitudinal, or longitudinal and circular muscles, which operated through a hydrostatic skeleton to protract and retract the head, to open and close the operculum, and to move the appendages. Although the shell form and skeletal ultra-structure of hyoliths are of a molluscan type, the muscle insertions suggest that the hyolith cone is not homologous with the dorsal exoskeleton of primitive molluscs. Hyoliths probably constitute a small extinct branch of phylum size, related to the Mollusca and the Sipunculoidea. All three groups may have had common ancestors in the late Precambrian.", "keyphrases": ["hyolith", "operculum", "pair"]}
{"id": "10.1098/rstb.1991.0068", "title": "Fossil evidence of interactions between plants and plant-eating mammals.", "abstract": "We document changes in mammalian dietary and foraging locomotor adaptation, and appearances and developments of angiosperm fruiting strategies and vegetation types since the late Cretaceous in the Euramerican region, and to some extent in low latitude Africa. These changes suggest: (i): an expansion in the exploitation of dry fruits and seeds by mammals on the ground as well as in the trees after the terminal Cretaceous dinosaur extinction; (ii) a relation between large nuts and rodents, which appear in the late Palaeocene and radiate in the late Eocene; (iii) a relation between primates and fleshy fruits established in the early-Middle Eocene when tropical forests reached their maximum latitudinal extent; (iv) a hiatus of several million years in the vertebrate exploitation of leaves after dinosaur extinction and before the first few mammalian herbivores in the Middle Palaeocene, followed by an expansion in the late Eocene when climates cooled and more open vegetation became established.", "keyphrases": ["late palaeocene", "eocene", "forest"]}
{"id": "10.1080/02724630903409071", "title": "A reappraisal of the origin and basal radiation of the Osteichthyes", "abstract": "ABSTRACT The earliest Actinoptergyii (ray-finned fishes) and Sarcopterygii (lobe-finned fishes) have been studied intensely, and a consistent picture of interrelationships has begun to emerge for the latter. In contrast, there has been minimal documentation of the pattern of character acquisition leading to the osteichthyan crown. We review the synapomorphies proposed for various levels within osteichthyan phylogeny (total group; Acanthodes + crown group; crown group; Sarcoptergyii; Actinopterygii), confirming some, rejecting others, and making new additions. This distribution of characters is used to interpret the placement of problematic Siluro-Devonian genera traditionally assigned to Actinopterygii, and suggests these taxa are stem osteichthyans. Earlier placements of these forms within the crown are symptomatic of taxonomies based on unpolarized similarities rather than synapomorphies.", "keyphrases": ["ray-finned fish", "crown", "total group", "stem osteichthyan"]}
{"id": "paleo.003081", "title": "Palaeoecological reconstruction of the late Oligocene Maar Lake of Enspel, Germany using lacustrine organic walled algae", "abstract": "The fine laminated black pelites of fossil Lake Enspel (Upper Oligocene, Westerwald, W-Germany) have been analysed using palynological methods. With the help of lacustrine organic walled algae it was possible to reconstruct some aspects of the ecology of the palaeolake. Two organic walled primary producers have been recognized (Botryococcus and the freshwater dinoflagellate Cleistosphaeridium lacustre). During holomictic periods of the lake, freshwater dinoflagellates and Botryococcus coexisted. In more meromictic phases, however, Botryococcus and Cleistosphaeridium lacustre act as competitors. During times of oligotrophic and acidic water conditions with less or nearly no nutrient input into the lake, Botryococcus was prevailing. In times with more eutrophic and alkaline water chemistry caused by increasing nutrient input into the palaeolake, Cleistosphaeridium lacustre was predominant. Subordinate algal cysts of Zygnemataceae together with pollen of shore plants (Typha, Sparganium) indicate areas of shallow water or even a swampy shoreland of unknown size around Lake Enspel during some time periods.", "keyphrases": ["lake enspel", "zygnemataceae", "shallow water"]}
{"id": "paleo.010211", "title": "Sawfishes and Other Elasmobranch Assemblages from the Mio-Pliocene of the South Caribbean (Urumaco Sequence, Northwestern Venezuela)", "abstract": "The Urumaco stratigraphic sequence, western Venezuela, preserves a variety of paleoenvironments that include terrestrial, riverine, lacustrine and marine facies. A wide range of fossil vertebrates associated with these facies supports the hypothesis of an estuary in that geographic area connected with a hydrographic system that flowed from western Amazonia up to the Proto-Caribbean Sea during the Miocene. Here the elasmobranch assemblages of the middle Miocene to middle Pliocene section of the Urumaco sequence (Socorro, Urumaco and Codore formations) are described. Based on new findings, we document at least 21 taxa of the Lamniformes, Carcharhiniformes, Myliobatiformes and Rajiformes, and describe a new carcharhiniform species (\u2020Carcharhinus caquetius sp. nov.). Moreover, the Urumaco Formation has a high number of well-preserved fossil Pristis rostra, for which we provide a detailed taxonomic revision, and referral in the context of the global Miocene record of Pristis as well as extant species. Using the habitat preference of the living representatives, we hypothesize that the fossil chondrichthyan assemblages from the Urumaco sequence are evidence for marine shallow waters and estuarine habitats.", "keyphrases": ["paleoenvironment", "lacustrine", "marine facie"]}
{"id": "paleo.012827", "title": "Facial Morphogenesis of the Earliest Europeans", "abstract": "The modern human face differs from that of our early ancestors in that the facial profile is relatively retracted (orthognathic). This change in facial profile is associated with a characteristic spatial distribution of bone deposition and resorption: growth remodeling. For humans, surface resorption commonly dominates on anteriorly-facing areas of the subnasal region of the maxilla and mandible during development. We mapped the distribution of facial growth remodeling activities on the 900\u2013800 ky maxilla ATD6-69 assigned to H. antecessor, and on the 1.5 My cranium KNM-WT 15000, part of an associated skeleton assigned to African H. erectus. We show that, as in H. sapiens, H. antecessor shows bone resorption over most of the subnasal region. This pattern contrasts with that seen in KNM-WT 15000 where evidence of bone deposition, not resorption, was identified. KNM-WT 15000 is similar to Australopithecus and the extant African apes in this localized area of bone deposition. These new data point to diversity of patterns of facial growth in fossil Homo. The similarities in facial growth in H. antecessor and H. sapiens suggest that one key developmental change responsible for the characteristic facial morphology of modern humans can be traced back at least to H. antecessor.", "keyphrases": ["bone deposition", "resorption", "homo"]}
{"id": "10.1890/09-2138.1", "title": "Fossil insect folivory tracks paleotemperature for six million years", "abstract": "Paleoecological studies enhance our understanding of biotic response to climate change because they consider timescales not accessible through laboratory or ecological studies. From 60 to 51 million years ago (Ma), global temperatures gradually warmed to the greatest sustained highs of the last 65 million years. Superimposed on this gradual warming is a transient spike of high temperature and pCO2 (partial pressure of carbon dioxide in the atmosphere; the Paleocene-Eocene Thermal Maximum 55.8 Ma) and a subsequent short-term cooling event (\u223c54 Ma). The highly resolved continental fossil record of the Bighorn Basin, Wyoming, USA, spans this interval and is therefore uniquely suited to examine the long-term effects of temperature change on the two dominant groups in terrestrial ecosystems, plants and insect herbivores. We sampled insect damage on fossil angiosperm leaves at nine well-dated localities that range in age from 52.7 to 59 Ma. A total of 9071 leaves belonging to 107 species were examined for the presence or absence of 71 insect-feeding damage types. Damage richness, frequency, and composition were analyzed on the bulk floras and individual host species. Overall, there was a strong positive correlation between changes in damage richness and changes in estimated temperature, a weak positive relationship for damage frequency and temperature, and no significant correlation for floral diversity. Thus, insect damage richness appears to be more sensitive to past climate change than to plant diversity, although plant diversity in our samples only ranges from 6 to 25 dicot species. The close tracking of the richness of herbivore damage, a presumed proxy for actual insect herbivore richness, to both warming and cooling over a finely divided, extended time interval has profound importance for interpreting the evolution of insects and plant\u2013insect associations in the context of deep time. Our results also indicate that increased insect herbivory is likely to be a net long-term effect of anthropogenic warming.", "keyphrases": ["damage type", "frequency", "fossil leave"]}
{"id": "10.2110/palo.2013.133", "title": "DINOSAUR-BEARING HYPERCONCENTRATED FLOWS OF CRETACEOUS ARCTIC ALASKA: RECURRING CATASTROPHIC EVENT BEDS ON A DISTAL PALEOPOLAR COASTAL PLAIN", "abstract": "ABSTRACT The Cretaceous coastal plain of Arctic Alaska contains the richest concentration of high-latitude dinosaurs on Earth. Three bonebeds (Liscomb, Byers, Sling Point) are found in paleopolar (82\u00b0\u201385\u00b0 N) coastal-plain deposits of the Prince Creek Formation on Alaska's North Slope. 40Ar/39Ar analysis of a tuff below the oldest bonebed (Sling Point) returned an age of 69.2 \u00b1 0.5 Ma indicating a maximum early Maastrichtian age for these bonebeds. Bonebeds are overwhelmingly dominated by partially articulated to associated late-stage juvenile Edmontosaurus sp. Bone is rarely found in channels; instead high-density accumulations are preserved on floodplains in laterally extensive, muddy alluvium. Bone size grading is vertically nonuniform and most bones are in hydraulic disequilibrium with the surrounding clay-rich matrix. Bones exhibit little evidence of rounding, weathering, predation, or trampling, suggesting short-distance transport and rapid burial. Because these bonebeds are unlike typical debris-flow or streamflow deposits, the mechanism for bonebed emplacement remained poorly understood. All bonebeds contain a current-rippled siltstone containing the largest bone overlain by a distinctive mudstone encasing smaller bones, bone fragments, and subparallel-aligned plant fragments that appear \u201cfrozen in flow\u201d within the muddy matrix. We recognize that these bonebeds exhibit a recurring facies pairing and bipartite division of flow consistent with deposition by fine-grained viscous hyperconcentrated flows. We suggest that exceptional discharge events entrained mud and ash stored on point bars and floodplains, increasing suspended-sediment concentrations in rivers and generating erosive hyperconcentrated flows that transported the remains of scores of juvenile dinosaurs onto floodplains adjacent to distributary channels.", "keyphrases": ["prince creek formation", "early maastrichtian age", "mudstone"]}
{"id": "10.1111/pala.12206", "title": "The Beothukis/Culmofrons problem and its bearing on Ediacaran macrofossil taxonomy: evidence from an exceptional new fossil locality", "abstract": "The late Ediacaran siliciclastic successions of eastern Newfoundland, Canada, are renowned for their fossils of soft\u2010bodied macro\u2010organisms, which may include some of the earliest animals. Despite the potential importance of such fossils for evolutionary understanding, the taxonomic framework within which Ediacaran macrofossils are described is not clearly defined. Rangeomorphs from a newly discovered fossil surface on the Bonavista Peninsula, Newfoundland, require us to reconsider contemporary use of morphological characters to distinguish between genera and species within Ediacaran taxa. The new surface exhibits remarkable preservational fidelity, resolving features smaller than 0.1 mm in dimension in both frondose and non\u2010frondose taxa. Such preservation permits the recognition of rarely observed fourth\u2010 and fifth\u2010order rangeomorph branching, offering unparalleled opportunities to investigate the fine\u2010scale construction of rangeomorph taxa including Culmofrons plumosa Laflamme et al., 2012. Our observations enable resolution of taxonomic issues relating to rangeomorphs, specifically overlap between the diagnoses of the frondose genera Beothukis Brasier and Antcliffe, 2009 and Culmofrons. We propose a taxonomic framework for all Ediacaran macrofossils whereby gross architecture, the presence/absence of discrete morphological characters and consideration of growth programme are used to distinguish genera, whereas morphometric or continuous characters define taxa at the species level. On the basis of its morphological characters, Culmofrons plumosa is herein synonymized to a species (Beothukis plumosa comb. nov.) within the genus Beothukis. This discussion emphasizes the need to standardize the taxonomic approach used to describe Ediacaran macrofossil taxa at both the genus and species levels, and raises important considerations for future formulation of higher\u2010level taxonomic groups.", "keyphrases": ["culmofrons", "ediacaran macrofossil", "newfoundland", "preservational fidelity", "rangeomorph taxa"]}
{"id": "paleo.009550", "title": "Gregarious suspension feeding in a modular Ediacaran organism", "abstract": "Simulations show fossil Ernietta (548 Ma ago) lived gregariously to aid feeding, providing one of the oldest examples of commensalism. Reconstructing Precambrian eukaryotic paleoecology is pivotal to understanding the origins of the modern, animal-dominated biosphere. Here, we combine new fossil data from southern Namibia with computational fluid dynamics (CFD) to test between competing feeding models for the Ediacaran taxon Ernietta. In addition, we perform simulations for multiple individuals, allowing us to analyze hydrodynamics of living communities. We show that Ernietta lived gregariously, forming shallow marine aggregations in the latest Ediacaran, 548 to 541 million years (Ma) ago. We demonstrate enhanced vertical mixing of the water column above aggregations and preferential redirection of current into body cavities of downstream individuals. These results support the reconstruction of Ernietta as a macroscopic suspension feeder and also provide a convincing paleoecological advantage to feeding in aggregations analogous to those recognized in many extant marine metazoans. These results provide some of the oldest evidence of commensal facilitation by macroscopic eukaryotes yet recognized in the fossil record.", "keyphrases": ["ernietta", "fluid dynamic", "cfd", "water column"]}
{"id": "10.1071/BT00031", "title": "Where and why have all the flowers gone? Depletion and turnover in the New Zealand Cenozoic angiosperm flora in relation to palaeogeography and climate", "abstract": "The modern New Zealand angiosperm flora has many notable characteristics, such as a predominance of evergreen, perennial life forms, few nitrogen-fixing species, despecialised floral features and asymmetric genus\u2014species relations. The origin of these features has been attributed to antiquity of the flora, isolation and/or environmental history. Using evidence from palynology and macrofossils, we investigate the characteristics of the mid\u2013late Cenozoic angiosperm flora and the impact of environmental changes in land area and configuration, physiography and climate on the depletion and composition of the New Zealand flora. Climatic cooling, increasing isolation and tectonism have each acted as important environmental filters, contributing to regional extinctions and decreasing floral diversity, and inducing major turnover in the floristic composition of New Zealand. During the Miocene and Pliocene at least 15 families and a minimum of 36 genera were lost from the New Zealand flora. These included a range of life forms and physiognomically important taxa such as Acacia, Bombax, Casuarina, Eucalyptus, Ilex, many Proteaceae and several palms. The extinction and decline in richness of subtropical families was caused by the onset of cooling conditions in the Late Miocene\u2014Pliocene, and exacerbated by the absence of significant land areas to act as refugia at lower latitudes. Many of these genera/families persist today on islands to the north (e.g. New Caledonia), reflecting mid-Cenozoic land conduits, and in Australia. The close floristic links with New Caledonia were probably maintained by intermittent island stepping-stones which facilitated interchange of subtropical taxa until the Late Miocene. The Pleistocene extinction of some genera, tolerant of warm-temperate environments (e.g. Acacia, Eucalyptus) may be a reflection of the fact that persistent mesic conditions favoured widespread dominance of dense rainforest during interglacials. The loss of these groups, containing diverse life forms and floral structures, suggests that many of the present characteristics of the New Zealand flora reflect strong selective pressures, mainly driven by climate change, in the Late Miocene, Pliocene and Pleistocene, rather than events of greater geological antiquity.", "keyphrases": ["new zealand", "environmental change", "floral structure"]}
{"id": "10.1080/14772019.2019.1578832", "title": "The first three-dimensional fossils of Cretaceous sclerorhynchid sawfish: Asflapristis cristadentis gen. et sp. nov., and implications for the phylogenetic relations of the Sclerorhynchoidei (Chondrichthyes)", "abstract": "A new fossil batoid (ray), Asflapristis cristadentis gen. et sp. nov., is described from six exceptionally well-preserved, three-dimensional skeletal remains from the Turonian (Late Cretaceous) of Morocco. Mechanical and acid preparation and computed tomographic scanning of these specimens reveal details of much of the proximal skeleton, especially the skull, synarcual and pectoral skeleton, with only the more distal parts of the skeleton missing. These fossils represent a relatively large animal (62\u2009cm preserved length, estimated total length approximately 2 metres) possessing a robust rostrum that lacks enlarged rostral denticles. It has a narrow and small chondrocranium with jaws that are relatively large compared to the rest of the skull and robust with highly ornamented teeth that lack cusps. The branchial skeleton shows a large second hypobranchial without an anterior process, which was probably fused to the basibranchial as in other sclerorhynchoids. The synarcual is large and lacks centra through its entire length, with no direct connection to the pectoral girdle observed. Pectoral fins probably possessed enlarged proximal elements (propterygium, mesopterygium and metapterygium); the articulation facet between the coracoid and the pectoral elements was reduced. A phylogenetic analysis using both parsimony and Bayesian methods was performed incorporating this new taxon. Both analyses recovered a phylogenetic topology that places the sclerorhynchoids in a close relation to rajoids and clearly separated from the morphologically similar Pristidae within the Rhinopristiformes. With respect to the extant taxa, the phylogenies generated are similar to that obtained from molecular analysis of modern batoids. The palaeoecological implication of this discovery suggests that the Asfla assemblage was not from a \u2018normal\u2019 open carbonate shelf but rather a restricted environment favouring a low-diversity chondrichthyan fauna. http://zoobank.org/urn:lsid:zoobank.org:pub:7752385F-817D-40BF-961C-1AF7B9093E14", "keyphrases": ["systematic palaeontology section", "other cretaceous sediment", "family ptychotrigonidae", "northern hemisphere", "albian"]}
{"id": "paleo.007375", "title": "Late Permian wood-borings reveal an intricate network of ecological relationships", "abstract": "Beetles are the most diverse group of macroscopic organisms since the mid-Mesozoic. Much of beetle speciosity is attributable to myriad life habits, particularly diverse-feeding strategies involving interactions with plant substrates, such as wood. However, the life habits and early evolution of wood-boring beetles remain shrouded in mystery from a limited fossil record.\nHere we report new material from the upper Permian (Changhsingian Stage, ca. 254-252 million-years ago) of China documenting a microcosm of ecological associations involving a polyphagan wood-borer consuming cambial and wood tissues of the conifer Ningxiaites specialis. This earliest evidence for a component community of several trophically interacting taxa is frozen in time by exceptional preservation. The combination of an entry tunnel through bark, a cambium mother gallery, and up to 11 eggs placed in lateral niches-from which emerge multi-instar larval tunnels that consume cambium, wood and bark-is ecologically convergent with Early Cretaceous bark-beetle borings 120 million-years later.", "keyphrases": ["beetle", "wood", "component community"]}
{"id": "paleo.007974", "title": "Mud-trapped herd captures evidence of distinctive dinosaur sociality", "abstract": "A unique dinosaur assemblage from the Cretaceous beds of western Inner Mongolia preserves geologic and paleontologic data that clearly delineate both the timing and mechanism of death. Over twenty individuals of the ornithomimid Sinornithomimus dongi perished while trapped in the mud of a drying lake or pond, the proximity and alignment of the mired skeletons indicating a catastrophic mass mortality of a social group. Histologic examination reveals the group to consist entirely of immature individuals between one and seven years of age, with no hatchlings or mature individuals. The Sinornithomimus locality supports the interpretation of other, more taphonomically ambiguous assemblages of immature dinosaurs as reflective of juvenile sociality. Adults of various nonavian dinosaurs are known to have engaged in prolonged nesting and post hatching parental care, a life history strategy that implies juveniles spent considerable time away from reproductively active adults. Herding of juveniles, here documented in a Cretaceous ornithomimid, may have been a common life history strategy among nonavian dinosaurs reflecting their oviparity, extensive parental care, and multi-year maturation.", "keyphrases": ["proximity", "catastrophic mass mortality", "social group", "hatchling", "nesting"]}
{"id": "paleo.007823", "title": "Time-calibrated models support congruency between Cretaceous continental rifting and titanosaurian evolutionary history", "abstract": "Recent model-based phylogenetic approaches have expanded upon the incorporation of extinct lineages and their respective temporal information for calibrating divergence date estimates. Here, model-based methods are explored to estimate divergence dates and ancestral ranges for titanosaurian sauropod dinosaurs, an extinct and globally distributed terrestrial clade that existed during the extensive Cretaceous supercontinental break-up. Our models estimate an Early Cretaceous (approx. 135 Ma) South American origin for Titanosauria. The estimated divergence dates are broadly congruent with Cretaceous geophysical models of supercontinental separation and subsequent continental isolation while obviating the invocation of continuous Late Cretaceous continental connections (e.g. ephemeral land bridges). Divergence dates for mid-Cretaceous African and South American sister lineages support semi-isolated subequatorial African faunas in concordance with the gradual northward separation between South America and Africa. Finally, Late Cretaceous Africa may have linked Laurasian lineages with their sister South American lineages, though the current Late Cretaceous African terrestrial fossil record remains meagre.", "keyphrases": ["titanosaurian sauropod dinosaur", "south america", "africa"]}
{"id": "paleo.013098", "title": "A Hydrothermal-Sedimentary Context for the Origin of Life", "abstract": "Abstract Critical to the origin of life are the ingredients of life, of course, but also the physical and chemical conditions in which prebiotic chemical reactions can take place. These factors place constraints on the types of Hadean environment in which life could have emerged. Many locations, ranging from hydrothermal vents and pumice rafts, through volcanic-hosted splash pools to continental springs and rivers, have been proposed for the emergence of life on Earth, each with respective advantages and certain disadvantages. However, there is another, hitherto unrecognized environment that, on the Hadean Earth (4.5\u20134.0\u2009Ga), would have been more important than any other in terms of spatial and temporal scale: the sedimentary layer between oceanic crust and seawater. Using as an example sediments from the 3.5\u20133.33\u2009Ga Barberton Greenstone Belt, South Africa, analogous at least on a local scale to those of the Hadean eon, we document constant permeation of the porous, carbonaceous, and reactive sedimentary layer by hydrothermal fluids emanating from the crust. This partially UV-protected, subaqueous sedimentary environment, characterized by physical and chemical gradients, represented a widespread system of miniature chemical reactors in which the production and complexification of prebiotic molecules could have led to the origin of life. ", "keyphrases": ["environment", "sedimentary layer", "crust", "seawater"]}
{"id": "10.1130/B26073.1", "title": "Synoptic reconstruction of a major ancient lake system; Eocene Green River Formation, western United States", "abstract": "Numerous 40Ar/39Ar experiments on sanidine and biotite from 22 ash beds and 3 volcaniclastic sand beds from the Greater Green River, Piceance Creek, and Uinta Basins of Wyoming, Colorado, and Utah constrain \u223c8 m.y. of the Eocene Epoch. Multiple analyses were conducted per sample using laser fusion and incremental heating techniques to differentiate inheritance, 40Ar loss, and 39Ar recoil. When considered in conjunction with existing radioisotopic ages and lithostratigraphy, biostratigraphy, and magnetostratigraphy, these new age determinations facilitate temporal correlation of linked Eocene lake basins in the Laramide Rocky Mountain region at a significantly increased level of precision. To compare our results to the geomagnetic polarity time scale and the regional volcanic record, the ages of Eocene magnetic anomalies C24 through C20 were recalibrated using seven 40Ar/39Ar ages. Overall, the ages obtained for this study are consistent with the isochroneity of North American land-mammal ages throughout the study area, and provide precise radioisotopic constraints on several important biostratigraphic boundaries.\n\nApplying these new ages, average sediment accumulation rates in the Greater Green River Basin, Wyoming, were approximately three times faster at the center of the basin versus its ramp-like northern margin during deposition of the underfilled Wilkins Peak Member. In contrast, sediment accumulation occurred faster at the edge of the basin during deposition of the balanced filled to overfilled Tipton and Laney Members. Sediment accumulation patterns thus reflect basin-center\u2013focused accumulation rates when the basin was underfilled, and supply-limited accumulation when the basin was balanced filled to overfilled. Sediment accumulation in the Uinta Basin, at Indian Canyon, Utah, was relatively constant at \u223c150 mm/k.y. during deposition of over 5 m.y. of both evaporative and fluctuating profundal facies, which likely reflects the basin-margin position of the measured section. The most rapid sediment accumulation for the entire system (>1 m/k.y.) occurred between 49.0 and 47.5 Ma, when volcaniclastic materials from the Absaroka and/or Challis volcanic fields entered the Green River Formation lakes from the north.\n\nOur new ages combined with existing paleomagnetic and biostratigraphic control permit the first detailed synoptic comparison of lacustrine depositional environments in all the Green River Formation basins. Coupled with previously published paleocurrent observations, our detailed correlations show that relatively freshwater lakes commonly drained into more saline downstream lakes. The overall character of Eocene lake deposits was therefore governed in part by the geomorphic evolution of drainage patterns in the surrounding Laramide landscape. Freshwater (overfilled) lakes were initially dominant (53.5\u201352.0 Ma), possibly related to high erosion rates of remnant Cretaceous strata on adjacent uplifts. Expansion of balanced-fill lakes first occurred in all Green River Formation basins at 52.0\u201351.3 Ma and again between 49.6 and 48.5 Ma. Evaporative (underfilled) lakes occurred in various basins between 51.3 and 45.1 Ma, coincident with the end of the early Eocene climatic optima and subsequent onset of global cooling defined from marine record. However, evaporite intervals in the different depocenters were deposited at different times rather than being confined to a single episode of arid climate. Evaporative terminal sinks were initially located in the Greater Green River and Piceance Creek Basins (51.3\u201348.9 Ma), then gradually migrated southward to the Uinta Basin (47.1\u201345.2 Ma). This history is likely related to progressive southward construction of the Absaroka Volcanic Province, which constituted a major topographic and thermal anomaly that contributed to a regional north to south hydrologic gradient. The Greater Green River and Piceance Creek Basins were eventually filled from north to south with Absarokaderived detritus at sedimentation rates 1\u20132 orders of magnitude greater than the underlying lake deposits.", "keyphrases": ["green river formation", "wyoming", "colorado"]}
{"id": "10.1002/spp2.1098", "title": "A new enigmatic hyolith from the Cambrian of West Gondwana and its bearing on the systematics of hyoliths", "abstract": "The genus Aladraco nom. nov. is described and discussed, along with two species recognized from coeval strata of the lower traditional middle Cambrian, A. schloppensis (Wurm) from the Tannenknock Formation of the Franconian Forest region, Germany, and A. ougnatensis sp. nov. from the Jbel Wawrmast Formation of the eastern Anti\u2010Atlas, Morocco. Aladraco was formerly known as Oxyprymna Kiderlen, a preoccupied generic name requiring renaming of the genus. The genus bears morphological characters such as the size, shape and external ornamentation of the conch which clearly indicate a systematic position in the class Hyolitha. A number of characters, such as a tripartition into an axial chamber and lateral acuminate processes, and the course of the apertural margin, differ considerably from those seen in the two orders Hyolithida and Orthothecida, and appear to indicate distinct differences in functional morphology. However, similarities of the morphological characters with the known representatives of the Hyolithida suggest that the species are derived from this systematic group and should be dealt with as a hitherto unrecognized distinct suborder and family, introduced as Aladracina subord. nov. and Aladracidae fam. nov.", "keyphrases": ["morphological character", "hyolithida", "orthothecida"]}
{"id": "10.1086/589887", "title": "Integrating Molecular Phylogenetic and Paleobotanical Evidence on Origin of the Flower", "abstract": "Inferences on the origin of the angiosperm flower require consideration of other seed plants, especially fossils. Molecular data favor a relationship of Gnetales to conifers rather than to angiosperms, and both alternatives are equally parsimonious in terms of the morphological data set presented here. However, if molecular relationships among extant taxa are accepted, morphology still associates glossopterids, Pentoxylon, Bennettitales, and Caytonia with angiosperms. Bennettitales had flowerlike structures, but if Caytonia is sister to angiosperms, aggregation of fertile parts probably occurred independently in Bennettitales and angiosperms. These results and developmental genetic data are consistent with homology of the angiosperm bitegmic ovule with the cupule of glossopterids and Caytonia, while the carpel could represent a leaf and a cupule\u2010bearing axillary branch. Origin of an adaxial cross zone could produce a uniovulate, ascidiate carpel, as in living basal angiosperms. Stamens may represent similar units bearing two microsynangia. However, ovulate structures of Pentoxylon and Bennettitales are more difficult to interpret, and any homologue of the carpel wall in Caytonia is unclear. Further progress may require better understanding of homologies in known fossils and/or recognition of closer stem relatives of angiosperms. A proposed Cretaceous stem relative, Archaefructus, is more likely a crown\u2010group angiosperm related to Hydatellaceae (Nymphaeales).", "keyphrases": ["angiosperm", "seed plant", "conifer", "hydatellaceae"]}
{"id": "paleo.003486", "title": "Proteroctopus ribeti in coleoid evolution", "abstract": "Palaeontological data are key elements for inferring ancestral character states and the assembly of character complexes, but cephalopod fossils preserving soft tissues are very rare. The exceptionally well\u2010preserved, unique specimen of Jurassic Proteroctopus ribeti Fischer & Riou from the Lagerst\u00e4tte of La\u2010Voulte\u2010sur\u2010Rh\u00f4ne (c. 165 Ma, France) is one of the few fossil octopod related taxa, but is rarely considered in evolutionary studies. In this paper, we used synchrotron microtomography to reappraise its external characters and for the first time, to reveal its internal structures. A unique character association is found with two fins, head fused to the body, eight well\u2010developed arms with cirri and two rows of oblique suckers, a gladius and absence of an ink sac. The phylogenetic analysis indicates that Proteroctopus is a basal member of the Vampyropoda. However, this result should be interpreted with caution due to the number of unknown character states in the matrix. Contrary to previous assumptions, the phylogenetic position of Proteroctopus, as well as its stratigraphic occurrence, suggest that the arrangement of biserial suckers may be the ancestral condition in Vampyropoda.", "keyphrases": ["character state", "tissue", "sucker"]}
{"id": "paleo.001836", "title": "Structure and homology of Psittacosaurus tail bristles", "abstract": "We examined bristle\u2010like appendages on the tail of the Early Cretaceous basal ceratopsian dinosaur Psittacosaurus with laser\u2010stimulated fluorescence imaging. Our study reveals previously unknown details of these structures and confirms their identification as integumentary appendages. For the first time, we show that most bristles appear to be arranged in bundles and that they exhibit a pulp that widens towards the bristle base. We consider it likely that the psittacosaur bristles are structurally and developmentally homologous to similar filamentous appendages of other dinosaurs, namely the basal heterodontosaurid Tianyulong and the basal therizinosauroid theropod Beipiaosaurus, and attribute the greater robustness of the bristles of Psittacosaurus to a higher degree of cornification and calcification of its integument (both skin and bristles). Although the psittacosaur bristles are probably homologous with avian feathers in their origin from discrete cell populations, it is uncertain whether they developed from a follicle, one of the developmental hallmarks of true feathers. In particular, we note a striking resemblance between the psittacosaur bristles and the cornified spine on the head of the horned screamer, Anhima cornuta, an extant anseriform bird. Similar, albeit thinner keratinous filaments of extant birds are the \u2018beard\u2019 of the turkey, Meleagris gallopavo, and the crown of the Congo peafowl, Afropavo congensis. All of these structures of extant birds are distinct from true feathers, and because at least the turkey beard does not develop from follicles, detailed future studies of their development would be invaluable towards deepening our understanding of dinosaur filamentous integumentary structures.", "keyphrases": ["tail", "bristle", "beipiaosaurus", "skin"]}
{"id": "10.1098/rsbl.2018.0768", "title": "Detecting past changes in vegetation resilience in the context of a changing climate", "abstract": "Anthropogenic climate change is continuously altering ecological responses to disturbance and must be accounted for when examining ecological resilience. One way to measure resilience in ecological datasets is by considering the amount and duration of change from a baseline created by perturbations, such as disturbances like wildfire. Recovery occurs when ecological conditions return to equilibrium, meaning that no subsequent changes can be attributed to the effects of the disturbance, but climate change often causes the recovered state to differ from the previous baseline. The palaeoecological record provides an opportunity to examine these expectations because palaeoclimates changed continuously; few periods existed when environmental conditions were stationary. Here we demonstrate a framework for examining resilience in palaeoecological records against the backdrop of a non-stationary climate by considering resilience as two components of (i) resistance (magnitude of change) and (ii) recovery (time required to return) to predicted equilibrium values. Measuring these components of resilience in palaeoecological records requires high-resolution fossil (e.g. pollen) records, local palaeoclimate reconstructions, a model to predict ecological change in response to climate change, and disturbance records measured at the same spatial scale as the ecological (e.g. vegetation history) record. Resistance following disturbance is measured as the deviation of the fossil record from the ecological state predicted by the palaeoclimate records, and recovery time is measured as the time required for the fossil record to return to predicted values. We show that some cases may involve nearly persistent equilibrium despite large climate changes, but that others can involve a shift to a new state without any complete recovery.", "keyphrases": ["resilience", "climate change", "palaeoecological record", "backdrop", "pollen"]}
{"id": "paleo.007486", "title": "The early evolution of ray\u2010finned fishes", "abstract": "Ray\u2010finned fishes (Actinopterygii) constitute approximately half of all living vertebrate species. A stable hypothesis of relationships among major modern lineages has emerged over the past decade, supported by both anatomy and molecules. Diversity is unevenly partitioned across the actinopterygian tree, with most species concentrated within a handful of geologically young (i.e. Cretaceous) teleost clades. Extant non\u2010teleost groups are portrayed as \u2018living fossils\u2019, but this moniker should not be taken as evidence of especially primitive structure: each of these lineages is characterized by profound specializations. Attribution of fossils to the crowns and apical stems of Cladistia, Chondrostei and Neopterygii is uncontroversial, but placements of Palaeozoic taxa along deeper branches of actinopterygian phylogeny are less secure. Despite these limitations, some major outlines of actinopterygian diversification seem reasonably clear from the fossil record: low richness and disparity in the Devonian; elevated morphological variety, linked to increases in taxonomic dominance, in the early Carboniferous; and further gains in taxonomic dominance in the Early Triassic associated with earliest appearance of trophically diverse crown neopterygians.", "keyphrases": ["neopterygii", "richness", "important radiation"]}
{"id": "paleo.001595", "title": "Developmental transformations in Jurassic driftwood crinoids", "abstract": "The internal, multi-element skeleton of echinoderms can differentiate almost as much as that of the vertebrates. The implied probability of post-mortem disarticulation was bypassed in pelagic species, whose carcasses could sink directly onto toxic sea bottoms. Among them were isocrinids attached to driftwood. In the Toarcian Posidonia Shales they are represented by two easily distinguishable forms: (1) the giant and long-stemmed Seirocrinus was probably a passive tow-net filtrator; (2) the smaller and heavily cirrated Pentacrinites may have produced its own filter current, even though this assumption is in conflict with the distribution of muscles in present-day benthic Isocrinida. In a newly discovered colony of the smaller Early Liassic Pentacrinites fossilis, both strategies are found together. This leads to the hypothesis that the two Toarcian forms may also represent developmental stages of the same species. After the Toarcian, Seirocrinus (as either a taxon or a developmental stage) became extinct, probably due to shipworms reducing the drifting time of logs. In contrast, the proposed feeding style of Pentacrinites allowed it to return to the benthic realm, but in an inverted attitude. During this complex history, most adaptational changes required only heterochronic shifts in the development of tegmen, arms, pinnules, stem, and cirri. Unrelated pseudoplanktonic crinoids of earlier times show convergent adaptations with different pathways.", "keyphrases": ["crinoid", "seirocrinus", "colony"]}
{"id": "10.1080/08912960903458011", "title": "Mammalian faunas from the Pliocene and Pleistocene of Casablanca (Morocco)", "abstract": "In the frame of the Franco\u2013Moroccan \u2018Programme Casablanca\u2019, several important new Late Miocene to Late Pleistocene mammalian localities have been excavated in the Casablanca area. The rodent fauna of Lissasfa attests to faunal exchanges with Spain and shows that the \u2018Quaternary\u2019 of Casablanca dates back to the Late Miocene. Ahl al Oughlam, with more than 100 vertebrate species, is by far the richest paleontological locality of northwestern Africa, but shows that by Late Pliocene, at 2.5 Ma, faunas of this region were already less diverse than in eastern Africa. The Thomas and Oulad Hamida quarries yield, in several continental levels interstratified with high-marine transgressive ones, a succession of late Early to Late Pleistocene faunas associated with lithic industries and Homo remains, which greatly help calibrating mammalian evolution in this part of Africa. The Late Pleistocene is also documented by several new sites, all of which, unfortunately, were destroyed before they could be properly excavated. All sites are threatened by urbanisation, emphasising the need for preservation of the few remaining ones.", "keyphrases": ["most zoological group", "jaw fragment", "abundant remain"]}
{"id": "paleo.011724", "title": "Tracing the dynamic life story of a Bronze Age Female", "abstract": "Ancient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of high-resolution human mobility.", "keyphrases": ["mobility", "tissue", "possibility", "single individual"]}
{"id": "10.1666/07-029.1", "title": "Late Cretaceous Octobrachiate Coleoid Lower Jaws from the North Pacific Regions", "abstract": "Abstract Eight well-preserved cephalopod jaw fossils were discovered from the Upper Cretaceous (Santonian and Campanian) deposits of Vancouver Island, Canada, and Hokkaido, Japan. They occur individually in calcareous concretions and retain their three-dimensional architecture. Seven of them consist of a widely open outer lamella and a posteriorly projected inner lamella with a pointed rostrum. Both lamellae are made of fluorapatite, which may represent diagenetically altered chitin, and lack a calcareous element. Based on these diagnostic features, the seven jaw fossils are identified as lower jaws of the Coleoidea. Comparison with the lower jaws of modern coleoids allows us to distinguish the following new genera and species among them; Nanaimoteuthis jeletzkyi of the Order Vampyromorphida, and Paleocirroteuthis haggarti and P. pacifica of the Order Cirroctopodida. The lower jaws of these new taxa are clearly distinguished by having a much less projected inner lamella from those of modern and extinct species of the Superorder Decabrachia and the Order Octopodida. The maximum lengths of their outer lamellae (35.0\u201367.1 mm) are much larger than those of most modern vampyromorph and cirroctopodid species, indicating the large body size and weight of their owners. One of the other three lower jaws examined, characterized by a posteriorly extended outer lamella, may be assigned to the Octopodida. This study clearly demonstrates that large octobrachiate coleoids existed in the Late Cretaceous North Pacific.", "keyphrases": ["jaw", "modern coleoid", "new genera", "paleocirroteuthis haggarti"]}
{"id": "paleo.009052", "title": "Complex neuroanatomy in the rostrum of the Isle of Wight theropod Neovenator salerii", "abstract": "The discovery of large, complex, internal canals within the rostra of fossil reptiles has been linked with an enhanced tactile function utilised in an aquatic context, so far in pliosaurids, the Cretaceous theropod Spinosaurus, and the related spinosaurid Baryonyx. Here, we report the presence of a complex network of large, laterally situated, anastomosing channels, discovered via micro-focus computed tomography (\u03bcCT), in the premaxilla and maxilla of Neovenator, a mid-sized allosauroid theropod from the Early Cretaceous of the UK. We identify these channels as neurovascular canals, that include parts of the trigeminal nerve; many branches of this complex terminate on the external surfaces of the premaxilla and maxilla where they are associated with foramina. Neovenator is universally regarded as a \u2018typical\u2019 terrestrial, predatory theropod, and there are no indications that it was aquatic, amphibious, or unusual with respect to the ecology or behaviour predicted for allosauroids. Accordingly, we propose that enlarged neurovascular facial canals shouldn\u2019t be used to exclusively support a model of aquatic foraging in theropods and argue instead that an enhanced degree of facial sensitivity may have been linked with any number of alternative behavioural adaptations, among them defleshing behaviour, nest selection/maintenance or social interaction.", "keyphrases": ["maxilla", "neurovascular canal", "branch", "foramina", "behaviour"]}
{"id": "10.1093/sysbio/syx064", "title": "Genomic Signature of an Avian Lilliput Effect across the K\u2010Pg Extinction", "abstract": "Abstract. Survivorship following major mass extinctions may be associated with a decrease in body size\u2014a phenomenon called the Lilliput Effect. Body size is a strong predictor of many life history traits (LHTs), and is known to influence demography and intrinsic biological processes. Pronounced changes in organismal size throughout Earth history are therefore likely to be associated with concomitant genome\u2010wide changes in evolutionary rates. Here, we report pronounced heterogeneity in rates of molecular evolution (varying up to \u223c20\u2010fold) across a large\u2010scale avian phylogenomic data set and show that nucleotide substitution rates are strongly correlated with body size and metabolic rate. We also identify potential body size reductions associated with the Cretaceous\u2010Paleogene (K\u2010Pg) transition, consistent with a Lilliput Effect in the wake of that mass extinction event. We posit that selection for reduced body size across the K\u2010Pg extinction horizon may have resulted in transient increases in substitution rate along the deepest branches of the extant avian tree of life. This \u201chidden\u201d rate acceleration may result in both strict and relaxed molecular clocks over\u2010estimating the age of the avian crown group through the relationship between life history and demographic parameters that scale with molecular substitution rate. If reductions in body size (and/or selection for related demographic parameters like short generation times) are a common property of lineages surviving mass extinctions, this phenomenon may help resolve persistent divergence time debates across the tree of life. Furthermore, our results suggest that selection for certain LHTs may be associated with deterministic molecular evolutionary outcomes.", "keyphrases": ["lilliput effect", "phenomenon", "body size"]}
{"id": "paleo.000246", "title": "Adaptations to squid-style high-speed swimming in Jurassic belemnitids", "abstract": "Although the calcitic hard parts of belemnites (extinct Coleoidea) are very abundant fossils, their soft parts are hardly known and their mode of life is debated. New fossils of the Jurassic belemnitid Acanthoteuthis provided supplementary anatomical data on the fins, nuchal cartilage, collar complex, statoliths, hyponome and radula. These data yielded evidence of their pelagic habitat, their nektonic habit and high swimming velocities. The new morphological characters were included in a cladistic analysis, which confirms the position of the Belemnitida in the stem of Decabrachia (Decapodiformes).", "keyphrases": ["statolith", "habit", "decabrachia"]}
{"id": "paleo.008579", "title": "THE DISCOVERY, LOCAL DISTRIBUTION, AND CURATION OF THE GIANT AZHDARCHID PTEROSAURS FROM BIG BEND NATIONAL PARK", "abstract": "Field crews from The University of Texas at Austin first identified pterosaur remains from the Upper Cretaceous Javelina Formation of Big Bend National Park in 1971 and continued excavation of these animals for decades. The announcement of the giant Quetzalcoatlus northropi in 1975 by graduate student Douglas Lawson drew worldwide attention, and fossil preparators William Amaral and Robert Rainey discovered several key localities in a region informally called Pterodactyl Ridge that have been thoroughly collected and documented. The Pterodactyl Ridge sites produced hundreds of bones from surface collection and quarries through 1986, but later surface collection yielded poorer results. The majority of these elements represent an animal substantially smaller than Q. northropi, Quetzalcoatlus lawsoni Andres and Langston, 2021-historically referred to as Quetzalcoatlus sp. These and subsequent field expeditions from several institutions have reported occurrences of pterosaurs from both the Aguja and Javelina formations, but this study limits only the Javelina Formation material to pterosaurs. Quetzalcoatlus northropi is known within Big Bend National Park only from stream channel facies, and the smaller Q. lawsoni from the upper abandoned channel-lake facies at Pterodactyl Ridge. The lower abandoned channel-lake facies strata of Pterodactyl Ridge produce a third genus and species, Wellnhopterus brevirostris Andres and Langston, 2021. In addition, a smaller azhdarchid is found in the overbank floodplain facies.", "keyphrases": ["pterosaur", "university", "austin", "prefix"]}
{"id": "paleo.012887", "title": "Common Functional Correlates of Head-Strike Behavior in the Pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and Combative Artiodactyls", "abstract": "Background Pachycephalosaurs were bipedal herbivorous dinosaurs with bony domes on their heads, suggestive of head-butting as seen in bighorn sheep and musk oxen. Previous biomechanical studies indicate potential for pachycephalosaur head-butting, but bone histology appears to contradict the behavior in young and old individuals. Comparing pachycephalosaurs with fighting artiodactyls tests for common correlates of head-butting in their cranial structure and mechanics. Methods/Principal Findings Computed tomographic (CT) scans and physical sectioning revealed internal cranial structure of ten artiodactyls and pachycephalosaurs Stegoceras validum and Prenocephale prenes. Finite element analyses (FEA), incorporating bone and keratin tissue types, determined cranial stress and strain from simulated head impacts. Recursive partition analysis quantified strengths of correlation between functional morphology and actual or hypothesized behavior. Strong head-strike correlates include a dome-like cephalic morphology, neurovascular canals exiting onto the cranium surface, large neck muscle attachments, and dense cortical bone above a sparse cancellous layer in line with the force of impact. The head-butting duiker Cephalophus leucogaster is the closest morphological analog to Stegoceras, with a smaller yet similarly rounded dome. Crania of the duiker, pachycephalosaurs, and bighorn sheep Ovis canadensis share stratification of thick cortical and cancellous layers. Stegoceras, Cephalophus, and musk ox crania experience lower stress and higher safety factors for a given impact force than giraffe, pronghorn, or the non-combative llama. Conclusions/Significance Anatomy, biomechanics, and statistical correlation suggest that some pachycephalosaurs were as competent at head-to-head impacts as extant analogs displaying such combat. Large-scale comparisons and recursive partitioning can greatly refine inference of behavioral capability for fossil animals.", "keyphrases": ["dome", "impact force", "capability", "pachycephalosaurid"]}
{"id": "paleo.000161", "title": "Discovery of a Rare Pterosaur Bone Bed in a Cretaceous Desert with Insights on Ontogeny and Behavior of Flying Reptiles", "abstract": "A pterosaur bone bed with at least 47 individuals (wing spans: 0.65\u20132.35 m) of a new species is reported from southern Brazil from an interdunal lake deposit of a Cretaceous desert, shedding new light on several biological aspects of those flying reptiles. The material represents a new pterosaur, Caiuajara dobruskii gen. et sp. nov., that is the southermost occurrence of the edentulous clade Tapejaridae (Tapejarinae, Pterodactyloidea) recovered so far. Caiuajara dobruskii differs from all other members of this clade in several cranial features, including the presence of a ventral sagittal bony expansion projected inside the nasoantorbital fenestra, which is formed by the premaxillae; and features of the lower jaw, like a marked rounded depression in the occlusal concavity of the dentary. Ontogenetic variation of Caiuajara dobruskii is mainly reflected in the size and inclination of the premaxillary crest, changing from small and inclined (\u223c115\u00b0) in juveniles to large and steep (\u223c90\u00b0) in adults. No particular ontogenetic features are observed in postcranial elements. The available information suggests that this species was gregarious, living in colonies, and most likely precocial, being able to fly at a very young age, which might have been a general trend for at least derived pterosaurs.", "keyphrases": ["pterosaur", "southern brazil", "ontogenetic variation"]}
{"id": "paleo.012919", "title": "Study of the Histology of Leafy Axes and Male Cones of Glenrosa carentonensis sp. nov. (Cenomanian Flints of Charente-Maritime, France) Using Synchrotron Microtomography Linked with Palaeoecology", "abstract": "We report exceptionally well-preserved plant remains ascribed to the extinct conifer Glenrosa J. Watson et H.L. Fisher emend. V. Srinivasan inside silica-rich nodules from the Cenomanian of the Font-de-Benon quarry, Charente-Maritime, western France. Remains are preserved in three dimensions and mainly consist of fragmented leafy axes. Pollen cones of this conifer are for the first time reported and in some cases remain connected to leafy stems. Histology of Glenrosa has not previously been observed; here, most of internal tissues and cells are well-preserved and allow us to describe a new species, Glenrosa carentonensis sp. nov., using propagation phase-contrast X-ray synchrotron microtomography, a non-destructive technique. Leafy axes consist of characteristic helically arranged leaves bearing stomatal crypts. Glenrosa carentonensis sp. nov. differs from the other described species in developing a phyllotaxy 8/21, claw-shaped leaves, a thicker cuticle, a higher number of papillae and stomata per crypt. Pollen cones consist of peltate, helically arranged microsporophylls, each of them bearing 6\u20137 pollen sacs. The new high resolution tomographic approach tested here allows virtual palaeohistology on plants included inside a dense rock to be made. Most tissues of Glenrosa carentonensis sp. nov. are described. Lithological and palaeontological data combined with xerophytic features of Glenrosa carentonensis sp. nov. suggest that this conifer has been adapted to survive in harsh and instable environments such as coastal area exposed to hot, dry conditions.", "keyphrases": ["phyllotaxy", "claw-shaped leave", "cuticle"]}
{"id": "paleo.005222", "title": "Diversity and Evolution of Hunter-Schreger Band Configuration in Tooth Enamel of Perissodactyl Mammals", "abstract": "Four different Hunter-Schreger Band (HSB) configurations were observed in the teeth of fossil and extant Perissodactyla. This variability exceeds that observed in Artiodactyla or Proboscidea. The four HSB configurations represent two different evolutionary pathways. Transverse HSB found in many mammalian taxa outside the Perissodactyla represents the most primitive HSB configuration. It occurs in several primitive perissodactyl families and is retained in Palaeotheriidae and extant Equidae. Curved HSB evolved from transverse HSB and occurs in Tapiridae, Helaletidae, and Lophiodontidae, as well as in Ancylopoda and Titanotheriomorpha. This likely indicates independent evolution of curved HSB in two or more lineages, but the number of instances of parallelism of this configuration is obscured by uncertainty in the relationships among these taxa and by a lack of data for some important basal taxa. A second evolutionary pathway leads from transverse HSB via compound HSB to vertical HSB. Compound HSB were detected in Hyrachyidae, Deperetellidae, and the early rhinocerotid Uintaceras. Vertical HSB configuration characterizes the molar dentition of other Rhinocerotidae, Hyracodontidae, Indricotheriidae, and Amynodontidae. Often, the incisors of rhinocerotids retain traces of compound HSB. Thus the HSB configuration reflects phylogenetic relationships to some degree. The selective value of the modified HSB configurations is interpreted functionally as a mechanism to reduce abrasion during mastication, assuming that the perpendicular intersection of prisms with the actual grinding surfaces resists wear better than prisms running parallel to the occlusal surface.", "keyphrases": ["configuration", "tooth", "hsb", "incisor"]}
{"id": "paleo.004306", "title": "Flexibility along the Neck of the Neogene Terror Bird Andalgalornis steulleti (Aves Phorusrhacidae)", "abstract": "Background Andalgalornis steulleti from the upper Miocene\u2013lower Pliocene (\u22486 million years ago) of Argentina is a medium-sized patagornithine phorusrhacid. It was a member of the predominantly South American radiation of \u2018terror birds\u2019 (Phorusrhacidae) that were apex predators throughout much of the Cenozoic. A previous biomechanical study suggests that the skull would be prepared to make sudden movements in the sagittal plane to subdue prey. Methodology/Principal Findings We analyze the flexion patterns of the neck of Andalgalornis based on the neck vertebrae morphology and biometrics. The transitional cervical vertebrae 5th and 9th clearly separate regions 1\u20132 and 2\u20133 respectively. Bifurcate neural spines are developed in the cervical vertebrae 7th to 12th suggesting the presence of a very intricate ligamentary system and of a very well developed epaxial musculature. The presence of the lig. elasticum interespinale is inferred. High neural spines of R3 suggest that this region concentrates the major stresses during downstrokes. Conclusions/Significance The musculoskeletal system of Andalgalornis seems to be prepared (1) to support a particularly big head during normal stance, and (2) to help the neck (and the head) rising after the maximum ventroflexion during a strike. The study herein is the first interpretation of the potential performance of the neck of Andalgalornis in its entirety and we considered this an important starting point to understand and reconstruct the flexion pattern of other phorusrhacids from which the neck is unknown.", "keyphrases": ["terror bird", "phorusrhacidae", "predator"]}
{"id": "10.1080/02724634.2019.1673399", "title": "A New Large Late Cretaceous Lamniform Shark from North America, with Comments on the Taxonomy, Paleoecology, and Evolution of the Genus Cretodus", "abstract": "ABSTRACT We describe a partial skeleton of the Late Cretaceous shark, Cretodus, collected from the Blue Hill Shale (middle Turonian) in north-central Kansas, U.S.A. It consists of 134 disarticulated teeth, 61 vertebrae, 23 placoid scales, and fragments of calcified cartilage. The scale morphology suggests that Cretodus was a rather sluggish shark, and the vertebral morphology affirms its placement into Lamniformes. With a strong tendency towards monognathic heterodonty, the dental morphology indicates that the specimen belongs to a new species, C. houghtonorum, sp. nov., increasing the total known species of Cretodus to five. The five species can be divided into three distinct groups: the longiplicatus/semiplicatus-grade, gigantea/houghtonorum-grade, and crassidens-grade. Cretodus, that successively evolved by broadening the tooth crown. The individual of C. houghtonorum, sp. nov., is estimated to be about 515 cm in total length (TL). Our vertebra-based growth analysis suggests that the shark was about 118 cm TL at birth and that the species had an estimated maximum growth length of 684 cm TL. The large size at birth indicates that the intrauterine cannibalism behavior of embryos seen in extant lamniforms had already evolved by the Late Cretaceous. Where C. houghtonorum, sp. nov., preferred nearshore environments, the specimen co-occurred with isolated teeth of Squalicorax and fragments of two dorsal fin spines of a hybodont shark, circumstantially indicating that the individual of Cretodus fed on the much smaller hybodont and was scavenged by Squalicorax.", "keyphrases": ["lamniform", "shark", "placoid scale"]}
{"id": "10.1111/j.1475-4983.2004.00432.x", "title": "Early Triassic coprolites from Australia and their palaeobiological significance", "abstract": "Abstract:\u2002 Coprolites from the Arcadia Formation, Queensland, Australia, were studied in conjunction with the vertebrate fossil assemblages from two localities to maximize our understanding of the palaeoecology of these Early Triassic deposits. Criteria used by other researchers to identify the producers of coprolites were found to be of little value in the Arcadia Formation specimens. Using a combination of shape, biostratigraphic distribution, size and included remains some of the coprolites are attributed to basal archosauromorphs and fish whereas others could not be identified. Perhaps the most important attribute of the Arcadia coprolites is that they preserved rare organisms such as cyanobacteria, insects and other arthropods, and a diversity of fish. Estimates of the number of actinopterygians and dipnoans preserved in coprolites significantly increased relative abundance estimates based on skeletal elements alone. Although coprolites are an important source of palaeobiological information, this information is limited by our poor understanding of the taphonomic processes involved in the fossilization of faecal matter and by the near impossibility of assigning coprolites to specific producers.", "keyphrases": ["coprolite", "arcadia formation", "cyanobacteria"]}
{"id": "10.3389/fmars.2019.00504", "title": "Are Clay Minerals the Primary Control on the Oceanic Rare Earth Element Budget?", "abstract": "The rare earth elements (REEs) are an important tool for understanding biogeochemical cycling and sedimentary processes in the global ocean. However, ambiguities in the marine REE budgets, including questions around the dominant source of REEs to the ocean, hinder the application of this tool. A bottom-up model for REE release into the ocean has recently been proposed, driven by early diagenetic processes such as sediment dissolution, with potentially significant implications for the interpretation of marine REE and Nd isotope paleo-records. Here, our goal is to identify the phase or phases that interact with the pore fluids to drive such a benthic flux. We use new pore water REE, microbeam imaging and mineralogical data in combination with published pore water REE data to evaluate potential sedimentary REE host phases. Mineralogical and direct imaging observations suggest that authigenic Fe or Mn oxyhydroxides, which are widely considered a dominant REE host phase, are not sufficiently abundant sediment components to account for the high Nd concentrations recovered in reductive leaches, and are unlikely to be the primary source of pore water REEs. Pore water REE signatures similar to river sourced clays indicate a detrital clay dissolution source, while the spread in heavy to light REE enrichment in pore fluids and bottom waters relative to this clay source is best explained by fractionation during authigenic clay uptake of REEs. We therefore conclude that clay mineral dissolution and authigenesis are likely the primary influences on the REE cycling near the seafloor. We propose that the balance between dissolution and authigenesis controls the concentration, ratio of heavy and light REE abundances, and the isotopic composition of the pore waters. We discuss the implications of this hypothesis on an oceanic REE budget controlled by a benthic flux from a sedimentary REE source, and the use of authigenic neodymium isotopes as a paleoproxy for shifts in ocean circulation.", "keyphrases": ["ree", "flux", "pore water"]}
{"id": "10.1086/344489", "title": "Rethinking Pelvic Typologies and the Human Birth Mechanism1", "abstract": "Paleoanthropological reconstructions of childbirth in the genus Homo typically rely upon a model incorporating the evolution of a monotypic human birth mechanism. Two features characterize this proposed mechanism or pathway taken by the fetus through the birth canal: fetal rotation and neonate emergence in a position facing away from the mother. The evolution of these two features is said to facilitate birth through the bipedal pelvis but is also taken as evidence of the difficulty of human birth relative to that in other primates and our smallerbrained ancestors. In contrast, the present work takes the position that birth mechanisms vary now and probably did so in the past. The notion of a monotypic birth mechanism has been imported into paleoanthropological discourse from typological thinking in EuroAmerican biomedical practice and text. The history of anatomical descriptions of pelvic types and associated birth mechanisms shows a trend toward the concept of a singular normal birth mechanism in biomedical practice. This paper suggests that biomedically defined pelvic typologies constitute a static definition of human variation in pelvic morphology and that pelvic typology, in turn, has contributed to a static definition of the normal human birth process that has been incorporated into paleoanthropological models.", "keyphrases": ["birth", "primate", "notion"]}
{"id": "paleo.002481", "title": "STRUCTURAL MECHANICS OF PACHYCEPHALOSAUR CRANIA PERMITTED HEAD-BUTTING BEHAVIOR", "abstract": "Pachycephalosaurian dinosaurs have dorsally thickened crania and uniquely shaped frontoparietal domes in some genera, suggested as evidence for head-or flank-butting behavior. Trabeculae thought to have resisted impact compression are present as only one histological zone of some pachycephalosaur domes, and are surrounded superficially or replaced by thick compacta in adults. The capabilities of pachycephalosaurian crania for head-butting are testable by finite element analysis (FEA). FEA of 2-and 3-D dorsal skull shapes of adult Homalocephale and Pachycephalosaurus reveal that the domes could withstand considerable impact force at certain closing speeds, and that stress and strain would dissipate efficiently throughout the dorsal portion of the skull before reaching the brain. Greater vaulting of the dome permitted higher impact forces. An analysis restricted to the frontoparietal dome of a subadult pachycephalosaurine, with material properties corresponding to histological zones, shows higher compressive strain (not less) in the trabecular region. The trabecular zone, if present, would not have rigidly resisted compression but rather have allowed slight elastic compression and rebound. Modeled keratinous coverings of varying depth indicate reductions in force and energy transmission to underlying bone. FEA therefore leaves open the possibility of head-butting in both flat-and dome-headed pachycephalosaurs, especially at low collision speeds.", "keyphrases": ["dome", "capability", "considerable impact force", "brain"]}
{"id": "paleo.006618", "title": "First arboreal 'pelycosaurs' (Synapsida: Varanopidae) from the early Permian Chemnitz Fossil Lagerst\u00e4tte, SE Germany, with a review of varanopid phylogeny", "abstract": "A new fossil amniote from the Fossil Forest of Chemnitz (Sakmarian-Artinskian transition, Germany) is described as Ascendonanus nestleri gen. et sp. nov., based on five articulated skeletons with integumentary preservation. The slender animals exhibit a generalistic, lizard-like morphology. However, their synapsid temporal fenestration, ventrally ridged centra and enlarged iliac blades indicate a pelycosaur-grade affiliation. Using a renewed data set for certain early amniotes with a similar typology found Ascendonanus to be a basal varanopid synapsid. This is the first evidence of a varanopid from Saxony and the third from Central Europe, as well as the smallest varanopid at all. Its greatly elongated trunk, enlarged autopodia and strongly curved unguals, along with taphonomical observations, imply an arboreal lifestyle in a dense forest habitat until the whole ecosystem was buried under volcanic deposits. Ascendonanus greatly increases the knowledge on rare basal varanopids; it also reveals a so far unexpected ecotype of early synapsids. Its integumentary structures present the first detailed and soft tissue skin preservation of any Paleozoic synapsid. Further systematic results suggest a varanodontine position for Mycterosaurus, the monophyly of South African varanopids including Anningia and the distinction of a skeletal aggregation previously assigned to Heleosaurus, now renamed as Microvaranops parentis gen. et sp. nov.\nArboreality \u2022 Synapsid phylogeny \u2022 Adaptation \u2022 Cisuralian \u2022 Soft tissue preservation \u2022 Volcanic taphonomy Kurzfassung Basierend auf f\u00fcnf artikulierten Skeletten mit Hauterhaltung wird ein neuer, fossiler Amniot aus dem Versteinerten Wald von Chemnitz (Sakmarium-Artinskium-Grenzbereich, Deutschland) beschrieben als Ascendonanus nestleri gen. et sp. nov. Die schlanken Tiere sind von generalistischer, echsenhafter Gestalt. Demgegen\u00fcber zeigen die synapsiden Schl\u00e4fenfenster, ventral gekantete Zentren und vergr\u00f6\u00dferte Iliumbl\u00e4tter eine Zugeh\u00f6rigkeit zur Pelycosaurier-Stufe an. Unter Anwendung eines erneuerten Datensatzes f\u00fcr ausgew\u00e4hlte fr\u00fche Amnioten \u00e4hnlicher Typologie wird Ascendonanus zu basalen Varanopiden gestellt. Damit liegt der erste Nachweis eines Varanopiden aus Sachsen und der dritte aus Mitteleuropa vor, zudem der kleinste Varanopide \u00fcberhaupt. Sein besonders verl\u00e4ngerter Rumpf, vergr\u00f6\u00dferte Autopodien und stark gekr\u00fcmmte Krallen sowie taphonomische Beobachtungen legen eine arboreale Lebensweise inmitten eines dichten Waldhabitats nahe, bis das gesamte \u00d6kosystem von vulkanischen Ablagerungen versch\u00fcttet wurde. Ascendonanus erweitert die Kenntnis der seltenen basalen Varanopiden enorm, zumal er einen bei fr\u00fchen Synapsiden bisher unerwarteten \u00d6kotyp aufdeckt. Die Integumentstrukturen stellen die ersten detaillierten und durch Weichteile erhaltenen Hautfunde aller pal\u00e4ozoischen Synapsiden dar. Weitergehende systematische Ergebnisse deuten an: eine varanodontine Position f\u00fcr Mycterosaurus, die Monophylie", "keyphrases": ["varanopid", "integumentary preservation", "numerous habitat", "tree", "other organism"]}
{"id": "paleo.001606", "title": "The fish trace fossil Undichna from the Cretaceous of Spain", "abstract": "The Early Cretaceous Spanish localities of El Montsec and Las Hoyas have yielded the fish trails Undichna britannicaandUndichna unisulcaichnosp. nov. respectively. The former consists of two intertwined waves, and was probably produced by the elopiform Ichthyemidion vidali . Undichna unisulcais characterized by having only a single sinusoidal wave, and was most probably produced by the pycnodontiforms Eo esodonand/or Macromesodon . Reliable criteria that distinguish this ichnospecies from the putative single-waved undertrails of more complex trails include the presence of hyporeliefs below undisturbed lamination and the preservation of epireliefs with lateral levees. The Spanish occurrences represent the first mention of this ichnogenus in post-Palaeozoic strata, and demonstrate that Undichnais not restricted to the Carboniferous\u2013Permian, as previously thought. The lacustrine depositional setting of the two Cretaceous localities is consistent with the known palaeoenvironmental distribution of this ichnotaxon. The disparity between the stratigraphical record of Undichnaand the broad temporal and palaeoenvironmental distribution of fishes capable of producing similar sinusoidal structures presumably reflects a taphonomic filter. Preservation of Undichna is favoured by: absence or scarcity of infaunal burrowers; presence of a very fine-grained, plastic, semiconsolidated substrate; low-energy bottom conditions; and relatively rapid burial with no associated erosion. Freshwater settings present these taphonomic constraints more frequently than other environments; thus preservation of Undichnais favoured in lakes, alluvial swamps and inner regions of estuaries. SI N C E its diagnosis by Anderson (1976) on the basis of material from the Lower Permian of South Africa, the fish ichnogenusUndichnahas been extensively recorded from strata of Late Palaeozoic age in the United States (Archer and Maples 1984; Rindsberg 1990; Buatois e al. 1997), England (Higgs 1988), the Czech Republic (Turek 1989) and Argentina (Buatois and Ma \u0301ngano 1993a, 1994a). Accordingly, this ichnotaxon seems to have been restricted to the Late Palaeozoic, and more precisely to the Late Namurian\u2013Early Permian (Buatois and Ma \u0301ngano 1994 a), apparently forming an exception to the rule that trace fossils are commonly typified by long temporal ranges (cf. Frey 1975). In this paper, the ichnogenus Undichna is described for the first time from Mesozoic beds. This ichnotaxon occurs in three Early Cretaceous Spanish localities, already well-known for their body fossil content: La Pedrera, La Cabru \u0301a, and Las Hoyas. The occurrence of Undichna at La Pedrera was mentioned, but not described, by Gibert (1994, 1995 a, 1995b). In addition, the ocurrence of a new ichnospecies ofUndichna is documented from Las Hoyas. The purpose of this contribution is to describe formally theUndichnafrom La Pedrera and La Cabru \u0301a, to diagnose the new ichnospecies from Las Hoyas, to identify the fishes that may have produced these traces, and to discuss stratigraphical, palaeoenvironmental, and taphonomic aspects of the ichnogenus. G E O L O G I C A L S E T T I N G A N D S T R A T I G R A P H Y The fish trace fossils described and discussed herein come from three different Spanish fossil sites of Early Cretaceous age and lacustrine origin: La Pedrera and La Cabru \u0301a (Serra del Montsec, south-central Pyrenees, province of Lleida) and Las Hoyas (Serran\u0131 \u0301a de Cuenca, Iberian Range, province of Cuenca) (Text-fig. 1A). [Palaeontology, Vol. 42, Part 3, 1999, pp. 409\u2013427, 1 pl.] q The Palaeontological Association 410 P A L A E O N T O L O G Y , V O L U M E 4 2", "keyphrases": ["trace", "infaunal burrower", "burial"]}
{"id": "10.1021/acs.jproteome.6b00873", "title": "Expansion for the Brachylophosaurus canadensis Collagen I Sequence and Additional Evidence of the Preservation of Cretaceous Protein.", "abstract": "Sequence data from biomolecules such as DNA and proteins, which provide critical information for evolutionary studies, have been assumed to be forever outside the reach of dinosaur paleontology. Proteins, which are predicted to have greater longevity than DNA, have been recovered from two nonavian dinosaurs, but these results remain controversial. For proteomic data derived from extinct Mesozoic organisms to reach their greatest potential for investigating questions of phylogeny and paleobiology, it must be shown that peptide sequences can be reliably and reproducibly obtained from fossils and that fragmentary sequences for ancient proteins can be increasingly expanded. To test the hypothesis that peptides can be repeatedly detected and validated from fossil tissues many millions of years old, we applied updated extraction methodology, high-resolution mass spectrometry, and bioinformatics analyses on a Brachylophosaurus canadensis specimen (MOR 2598) from which collagen I peptides were recovered in 2009. We recovered eight peptide sequences of collagen I: two identical to peptides recovered in 2009 and six new peptides. Phylogenetic analyses place the recovered sequences within basal archosauria. When only the new sequences are considered, B. canadensis is grouped more closely to crocodylians, but when all sequences (current and those reported in 2009) are analyzed, B. canadensis is placed more closely to basal birds. The data robustly support the hypothesis of an endogenous origin for these peptides, confirm the idea that peptides can survive in specimens tens of millions of years old, and bolster the validity of the 2009 study. Furthermore, the new data expand the coverage of B. canadensis collagen I (a 33.6% increase in collagen I alpha 1 and 116.7% in alpha 2). Finally, this study demonstrates the importance of reexamining previously studied specimens with updated methods and instrumentation, as we obtained roughly the same amount of sequence data as the previous study with substantially less sample material. Data are available via ProteomeXchange with identifier PXD005087.", "keyphrases": ["collagen", "protein", "dna", "million"]}
{"id": "paleo.003267", "title": "Helodermatid Lizard from the Mio-Pliocene Oak-Hickory Forest of Tennessee, Eastern USA, and a Review of Monstersaurian Osteoderms", "abstract": "The extant venomous Gila monster and beaded lizards, species of Heloderma, live today in southwestern USA and south along the Pacific coastal region into Central America, but their fossil history is poorly understood. Here we report helodermatid osteoderms (dermal ossicles) from the late Miocene-early Pliocene Gray Fossil Site, eastern Tennessee USA. Twenty-three species of mammals are known from the fauna including abundant Tapirus polkensis, as well as fishes, anurans, salamanders, turtles, Alligator, birds, and snakes. Beaded lizards belong to the Monstersauria, a clade that includes Primaderma + Paraderma + Gobiderma + Helodermatidae (Estesia, Eurheloderma, Lowesaurus, and Heloderma). Osteoderms of lizards in this clade are unique within Squamata; they typically are circular to polygonal in outline, domed to flat-domed in cross-section, have a vermiculate surface texture, are not compound structures, and do not have imbricate surfaces as on many scincomorph and anguid lizards. We review and characterize the osteoderms of all members of Monstersauria. Osteoderms from the cranium, body, and limbs of Heloderma characteristically have a ring-extension (bony flange) at least partly surrounding the dome. Its presence appears to be a key character distinct to all species of Heloderma, consequently, we propose the presence of a ring-extension to be an apomorphy. Three osteoderms from the Gray Fossil Site range from 1.5 to 3.0 mm in diameter, have the circular shape of helodermatid osteoderms with a domed apical surface, and have the ring-extensions, permiting generic identification. Macrobotanical remains from the Gray Fossil Site indicate an oak-hickory subtropical forest dominated by Quercus (oak) and Carya (hickory) with some conifer species, an understorey including the climbing vines Sinomenium, Sargentodoxa, and Vitis. Plant and mammal remains indicate a strong Asian influence.", "keyphrases": ["lizard", "heloderma", "turtle"]}
{"id": "10.1130/G47944.1", "title": "Late Miocene contourite channel system reveals intermittent overflow behavior", "abstract": "\n Paleoceanographic information from submarine overflows in the vicinity of oceanic gateways is of major importance for resolving the role of ocean circulation in modulating Earth\u2019s climate. Earth system models are currently the favored way to study the impact of gateways on global-scale processes, but studies on overflow-related deposits are more suitable to understand the detailed changes. Such deposits, however, had not yet been documented in outcrop. Here, we present a unique late Miocene contourite channel system from the Rifian Corridor (Morocco) related to the initiation of Mediterranean Outflow Water (MOW). Two channel branches were identified consisting of three vertically stacked channelized sandstone units encased in muddy deposits. Both branches have different channel-fill characteristics. Our findings provide strong evidence for intermittent behavior of overflow controlled by tectonic processes and regional climatic change. These fluctuations in paleo-MOW intermittently influenced global ocean circulation.", "keyphrases": ["outcrop", "rifian corridor", "morocco"]}
{"id": "10.1080/14772019.2015.1059985", "title": "Systematics, phylogeny and palaeobiogeography of the ankylosaurid dinosaurs", "abstract": "The Ankylosauria is a group of herbivorous, quadrupedal, armoured dinosaurs subdivided into at least two major clades, the Ankylosauridae and the Nodosauridae. The most derived members of Ankylosauridae had a unique tail club formed from modified, tightly interlocking distal caudal vertebrae and enlarged osteoderms that envelop the terminus of the tail. We review all known ankylosaurid species, as well as ankylosaurs of uncertain affinities, in order to conduct a revised phylogenetic analysis of the clade. The revised phylogenetic analysis resulted in a monophyletic Ankylosauridae consisting of Ahshislepelta, Aletopelta, Gastonia, Gobisaurus, Liaoningosaurus, Shamosaurus and a suite of derived ankylosaurids (Ankylosaurinae). There is convincing evidence for the presence of nodosaurids in Asia during the Early Cretaceous. In the mid Cretaceous, Asian nodosaurids were replaced by ankylosaurine ankylosaurids. Ankylosaurines migrated into North America from Asia between the Albian and Campanian, where they diversified into a clade of ankylosaurines, here named Ankylosaurini, characterized by arched snouts and numerous flat cranial caputegulae. There is no evidence for any ankylosaurids in Gondwana; Ankylosauridae appears to be completely restricted to Asia and North America. The genus Crichtonpelta gen. nov. is created, type species Crichtonsaurus benxiensis L\u00fc et al. http://zoobank.org/urn:lsid:zoobank.org:pub:EE5B88A3-3353-4FB6-B9A2-FCF0F99770EB", "keyphrases": ["nodosauridae", "tail club", "osteoderm", "ankylosaur"]}