In 1876, Othniel C. Marsh described a skeleton as Eohippus validus, from Greek: ἠώς (eōs, 'dawn') and ἵππος (hippos, 'horse'), meaning 'dawn horse'.[citation needed] Its similarities with fossils described by Richard Owen were formally pointed out in a 1932 paper by Clive Forster Cooper. E. validus was moved to the genus Hyracotherium, which had priority as the name for the genus, with Eohippus becoming a junior synonym of that genus. Hyracotherium was recently found to be a paraphyletic group of species, and the genus now includes only H. leporinum. E. validus was found to be identical to an earlier-named species, Orohippus angustidens Cope, 1875,[3] and the resulting binomial is thus Eohippus angustidens.
Description
Eohippus stood at about 30 cm (12 in), or 3 hands tall, at the shoulder.[4] It has 4 toes on its front feet and 3 toes on the hinds, each toe ending in a hoof. Its incisors, molars and premolars resemble modern Equus. However, a differentiating trait of Eohippus is its large canine teeth.[5][4]
Stephen Jay Gould comments
In his 1991 essay, "The Case of the Creeping Fox Terrier Clone",[6]Stephen Jay Gould lamented the prevalence of a much-repeated phrase to indicate Eohippus size ("the size of a small Fox Terrier"), even though most readers would be quite unfamiliar with that breed of dog. He concluded that the phrase had its origin in a widely-distributed pamphlet by Henry Fairfield Osborn, and proposed that Osborn, a keen fox hunter, could have made a natural association between his horses and the dogs that accompanied them.[6]
