''Sphenocoelus'' is an extinct

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

brontothere Brontotheriidae is a family of extinct mammals belonging to the order Perissodactyla, the order that includes horses, rhinoceroses, and tapirs. Superficially, they looked rather like rhinos, although they were actually more closely related to ...

endemic to

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 ...

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 ...

46.2—40.4 mya), existing for approximately .''Sphenocoelus'' at fossilworks
/ref> Fossils have been found only in southern Wyoming and eastern Utah. In life, it would have resembled a hornless

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 ...

, to which it was distantly related. However, it was smaller than modern rhinos, standing about high at the shoulders, and had a much longer head. Its teeth were adapted to eating soft vegetation, such as forest leaves. Like other brontotheres, it had four toes on the front feet, and three on the hind feet, and the animal is unlikely to have been able to run fast.

Species

* ''S. blairi'' * ''S. bridgeri'' * ''S. harundivoras'' * ''S. hyognathus'' (syn. ''Dolichorhinus longiceps'', ''Telmatotherium cornutum'') * ''S. intermedius'' (syn. ''Dolichorhinus fluminalis'', ''D. heterodon'', ''Mesatirhinus superior'') * ''S. uintensis''.

References

Brontotheres Eocene mammals of North America Eocene odd-toed ungulates {{paleo-oddtoedungulate-stub