''Cormohipparion'' is an extinct genus of horse belonging to the

tribe The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English language, English is in the discipline of anthropology. This definition is contested, in p ...

Hipparionini Equinae is a subfamily of the family Equidae, which have lived worldwide (except Indonesia and Australia) from the Hemingfordian stage of the Early Miocene (16 million years ago) onwards. They are thought to be a monophyletic grouping.B. J. MacF ...

that lived in North America during the late Miocene to Pliocene (

Hemphillian The Hemphillian North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 10,300,000 to 4,900,000 years BP. It is usually considered ...

Blancan The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years Before Present, BP, a period of .

in the NALMA classification). This ancient species of horse grew up to long.

Taxonomy

The genus ''Cormohipparion'' was coined for the extinct hipparionin horse ''"Equus" occidentale'', described by

Joseph Leidy Joseph Mellick Leidy (September 9, 1823 – April 30, 1891) was an American paleontologist, parasitologist and anatomist. Leidy was professor of anatomy at the University of Pennsylvania, later was a professor of natural history at Swarthmore ...

in 1856. However it was soon argued that the partial material fell within the range of morphological variation seen in ''

Hipparion ''Hipparion'' (Greek, "pony") is an extinct genus of horse that lived in North America, Asia, Europe, and Africa during the Miocene through Pleistocene ~23 Mya—781,000 years ago. It lived in non-forested, grassy plains, shortgrass prairie or st ...

'', and that the members of ''Cormohipparion'' belonged instead within ''Hipparion''. This rested on claims that pre-orbital morphology did not have any taxonomic significance, a claim that detailed study of quarry sections later showed to be false. The genus was originally identified by a closed off preorbital fossa, but later examinations of the cheek teeth, specifically the lower

cheek teeth Cheek teeth or post-canines comprise the molar and premolar teeth in mammals. Cheek teeth are multicuspidate (having many folds or tubercles). Mammals have multicuspidate molars (three in placentals, four in marsupials, in each jaw quadrant) and ...

, of ''Cormohipparion'' specimens found that they were indeed valid and distinct from ''Hipparion''. A reappraisal of many horse genera was thus conducted in 1984, and the proposed synonymy was not acknowledged by later literature. ''C. ingenuum'' holds the distinction for being the first prehistoric horse to be described in Florida, as well as being one of the most common species of extinct species three-toed horses found to be in Florida. ''Cormohipparion'' ''emsliei'' has the distinction of being the last hipparion horse known from the fossil record. The genus is considered to represent an ancestor to ''

Hippotherium ''Hippotherium'' is an extinct genus of horse that lived in during the Miocene through Pliocene ~13.65—3.3 Mya, existing for . Species The type species, ''H. primigenius'', is known from Miocene deposits in Europe and the Middle East ...

''. Its fossils have been recovered from as far south as Mexico. Fossils have been found in the Great Plains and Rio Grande regions of North America, Mexico, Florida and Texas, which shows that they were herding animals.

References

Miocene horses Pliocene horses Zanclean genera Messinian genera Tortonian genera Langhian genera Serravallian genera Miocene mammals of North America Pliocene mammals of North America Hemphillian Blancan Neogene Honduras Neogene Mexico Neogene Panama Neogene United States Fossils of Honduras Fossils of Mexico Fossils of Panama Fossils of the United States Fossil taxa described in 1977 {{paleo-oddtoedungulate-stub