Cormohipparion

Skull

The genus Cormohipparion was coined for the extinct hipparionin horse "Equus" occidentale, described by Joseph Leidy in 1856.[4] However it was soon argued that the partial material fell within the range of morphological variation seen in Hipparion, and that the members of Cormohipparion belonged instead within Hipparion.[5][6] 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.[7] The genus was originally identified by a closed off preorbital fossa, but later examinations of the cheek teeth, specifically the lower cheek teeth, of Cormohipparion specimens found that they were indeed valid and distinct from Hipparion.[8] A reappraisal of many horse genera was thus conducted in 1984,[9] and the proposed synonymy was not acknowledged by later literature.[10] 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.[11] Cormohipparion emsliei has the distinction of being the last hipparion horse known from the fossil record.[12]

The genus is considered to represent an ancestor to Hippotherium.[13] Its fossils have been recovered from as far south as Mexico.[14] 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.[15][16][17][18]