News Finding: "Interestingly, we not only find hints of the missing digits on the modern horse, but also its ancestors, such as Hipparion and Mesohippus, two species believed to have three toes," Professor Solounias said.
Paper Finding: The external appearance of the hoof parallels our observation of the adult hoof subdivisions.
News Context: After further studying images of the Laetoli footprints, he confirmed his finding in several of the impressions, and considered that Hipparion not only had five compacted toes, but likely passed this trait on to its descendants. "Interestingly, we not only find hints of the missing digits on the modern horse, but also its ancestors, such as Hipparion and Mesohippus, two species believed to have three toes," Professor Solounias said. "While the horse's lineage is classically described as having evolved from four to three toes, and eventually one single toe, we show that its extinct ancestors exhibit the reduced toes both at the wrist and at the hoof," said co-author Melinda Danowitz, also from the New York Institute of Technology College of Osteopathic Medicine.
Paper Context: The common number of 'petals' is four on the ventral side and one on the dorsal. The external appearance of the hoof parallels our observation of the adult hoof subdivisions. Most distally these five petals, although they externally display distal borders, merge into a single undifferentiated cone, which extends further and terminates into a notably long and curved point like a median claw.