''Uintaceras'' is an extinct genus of medium-sized

rhinoceros A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...

that lived in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

(

Wyoming Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...

and

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

) during the

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...

, with only the type species ''U. radinskyi'', named in 1997, currently contained within the genus.L. T. Holbrook and S. G. Lucas. 1997. A New Genus of Rhinocerotoid from the Eocene of Utah and the Status of North American "''

Forstercooperia ''Forstercooperia'' is an extinct genus of forstercooperiine paraceratheriid rhinoceros from the Middle Eocene of Asia. Description ''Forstercooperia'' is known from a vast amount of cranial material, although only some scant postcranial remain ...

''". ''Journal of Vertebrate Paleontology'' 17(2):384-396 ''Uintaceras'' is the oldest and most primitive species of the Rhinocerotidae known to date, although it may have belonged to its own, currently unknown, separate family. The dubious species ''

'' (''

Hyrachyus ''Hyrachyus'' (from '' Hyrax'' and grc, ὗς "pig") is an extinct genus of perissodactyl mammal that lived in Eocene Europe, North America, and Asia. Its remains have also been found in Jamaica. It is closely related to ''Lophiodon''.Hayden, F. ...

'') ''grandis'' (Radinsky, 1967; Peterson, 1919)Peterson, O.A. (1919). "Report upon the Material Discovered in the Upper Eocene of the Uinta Basin by Earl Douglas in the years 1908-1909, and by 0. A. Peterson in 1912". ''Annals of the Carnegie Museum''. pp. 40–168. is also possibly the same animal as ''Uintaceras'', although the Asian material of ''F. grandis'' was assignable to ''Forstercooperia confluens''. ''Uintaceras'' weighed about when fully grown. It was a relatively slender animal and ''Uintaceras'' resembled a typical hyracodontid (e.g. ''

Hyracodon ''Hyracodon'' ('hyrax tooth') is an extinct genus of perissodactyl mammal. It was a lightly built, pony-like mammal of about 1.5 m (5 ft) long. ''Hyracodons skull was large in comparison to the rest of the body. ''Hyracodon's'' dentiti ...

''), 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.

References

Prehistoric mammals of North America Paleontology in Utah Paleontology in Wyoming Eocene rhinoceroses Fossil taxa described in 1997 Prehistoric mammals {{Paleo-oddtoedungulate-stub