Additional postcranial remains of omomyid primates from the Uinta Formation, Utah and implications for the locomotor behavior of large-bodied omomyids

The new specimens include several distal tibiae, partial calcanei, a complete talus and a proximal first metatarsal of Chipetaia; distal femora, distal tibiae, cuboids, and partial calcanei of Ourayia uintensis; a complete calcaneus of Ourayia sp.; and a partial calcaneus and talus of Mytonius. Metric analysis of these elements, together with qualitative observations of non-metric traits, indicate that Ourayia and Chipetaia show equal or greater development of traits associated with leaping behavior (including elongation of the calcaneus, navicular and cuboid) than do smaller omomyids from North America. The elements of Mytonius, although fragmentary, lack some leaping features that are well-developed in Ourayia and Chipetaia, suggesting that Mytonius may have relied more on arboreal quadrupedal locomotion than on leaping.