News Finding: Fragments of the 'missing' digits can be found in the form of ridges on the backside of the splints."
Paper Finding: This resembles the elevation seen on metacarpals II and IV in Equus, where it is expanded and triangular proximally and tapers distally into a thin ridge.
News Context: "While this explanation of the second and fourth digits is viable, it is incomplete and fails to account for the animal's first and fifth digits," the paleontologists said. Fragments of the 'missing' digits can be found in the form of ridges on the backside of the splints." According to the team, this demonstrates that the first and fifth digits were not simply lost to evolution, but attached to their neighboring second and fourth digits.
Paper Context: We believe these fusion lines indicate that the ridges are separate structures from the splint metacarpals, digits I and V, that throughout time have embedded onto the surfaces of digits II and V. In Hyracotherium, where digits II-V are fully present, only metacarpal II possesses a clear ventral ridge. This resembles the elevation seen on metacarpals II and IV in Equus, where it is expanded and triangular proximally and tapers distally into a thin ridge. The lack of ridges on the other metacarpals of Hyracotherium reinforces this hypothesis, as all other digits are already present.