Miocyon

Abstract: The middle Eocene of North American was an important time in carnivoramorphan evolution, because it is when the order showed increases in diversity taxonomically and ecomorphologically. We describe new fossils of “miacoids” from the Uinta Formation of northeastern Utah, and assess their phylogenetic and paleobiological significance. A new species of Miocyon (Matthew, 1909), is described, Miocyon vallisrubrae , which, in several aspects of lower molar morphology, is intermediate between the smaller Miocyon major (Matthew, 1909) and the larger Miocyon scotti (Wortman and Matthew, 1899). In addition, new well-preserved dental and gnathic specimens of M. scotti are described, along with fragmentary cranial and postcranial remains. The taxonomy of Miocyon is reviewed in light of the new material, which highlights the divergent specializations of the genus. These include an m1 with a relatively broad talonid and an m2 that is large, broad and relatively flat with little difference in height between the...