Eohippus is an extinct genus of small equid .
Discovery
In 1876, Othniel C. Marsh described a skeleton as
Eohippus validus, from (eōs, 'dawn') and ἵππος (hippos, 'horse'), meaning 'dawn horse'. 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,
and the resulting binomial is thus
Eohippus angustidens.
Description
Eohippus stood at about , or three hands tall, at the shoulder.
[ ] It had four toes on its front feet and three toes on the hind feet, each toe ending in a hoof. Its incisors, molars and premolars resemble modern
Equus. However, a differentiating trait of
Eohippus is the large canine teeth.
Stephen Jay Gould comments
In his 1991 essay, "The Case of the Creeping Fox Terrier Clone",
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.
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See also
