Uintaceras is an extinct genus of medium-sized early rhinocerotoids that lived in North America (Wyoming and Utah) during the Middle Eocene, with only the type species U. radinskyi, named in 1997, currently contained within the genus.[1][2] Traditionally considered the oldest and most primitive species of the Rhinocerotidae, it may instead have been a close relative of the AsianParaceratheriidae.[3] The dubious species Forstercooperia (Hyrachyus) grandis (Radinsky, 1967; Peterson, 1919)[4][5] is also possibly the same animal as Uintaceras,[2][6] although the Asian material of F. grandis was assignable to Forstercooperia confluens.
Uintaceras weighed about 220 kilograms (490lb) when fully grown.[citation needed] It was a relatively slender animal and Uintaceras resembled a typical hyracodontid (e.g. Hyracodon), but differed from the hyracodonts due to the presence of a primitive four-fingered hand and a number of other features of the structure of the legs, which were clearly not intended for fast and long running.[6]
12L. T. Holbrook and S. G. Lucas. 1997. A New Genus of Rhinocerotoid from the Eocene of Utah and the Status of North American "Forstercooperia". Journal of Vertebrate Paleontology 17(2):384-396
↑Peterson, O.A. (1919). "Report upon the Material Discovered in the Upper Eocene of the Uinta Basin by Earl Douglas[s] in the years 1908-1909, and by 0. A. Peterson in 1912". Annals of the Carnegie Museum. pp. 40–168.
12Prothero, D.R. (2005). The Evolution of North American Rhinoceroses. Cambridge University Press. pp.1–218. ISBN0-521-83240-3.
