Hippidion has been considered a descendant of pliohippines,[1] equines that migrated into the South American continent around 2.5 million years ago.[1][2] Early analysis of the ancient DNA of Hippidion and other New World Pleistocene equines supported the novel hypothesis that Hippidion was actually a member of the living genus Equus, with a particularly close relationship to the wild horse, Equus ferus.[1][2] However this was later shown to be incorrect, with more complete sequences finding Hippidion as an outgroup to all living equines[3] and less closely related to living equines than the "New World stilt legged horse", Haringtonhippus francisci.[4]
Hippidion is traditionally thought to have 3 species, H. principale, H. saldiasi and H. devillei, however, in a 2015 DNA analysis, the single sampled H. principale specimen was found to be nested with H. saldiasi, with H. devillei found to be clearly genetically distinct.[3]
Hippidion has been suggested to play 13 roles. Click below to see other actors suggested for each role, and vote for who you think would play the role best.
