Eohippus
| Eohippus Temporal range:
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|---|---|
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| Restoration by Heinrich Harder c. 1920 | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Perissodactyla |
| Family: | Equidae |
| Genus: | †Eohippus Marsh, 1876 |
| Species: | †E. angustidens
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| Binomial name | |
| †Eohippus angustidens (Cope, 1875)
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| Synonyms | |
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Eohippus is an extinct genus of small equid ungulates.[1] The only species is E. angustidens, which was long considered a species of Hyracotherium. Its remains have been identified in North America and date to the Early Eocene (Ypresian) stage.[2]
Discovery
In 1876, Othniel C. Marsh described a skeleton as Eohippus validus, from the Greek ἠώς (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 Sir 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, Hyracotherium angustidens (Cope, 1875), and the resulting binomial is thus Eohippus angustidens.
Stephen Jay Gould comments
In his essay, "The Case of the Creeping Fox Terrier Clone",[3] Stephen Jay Gould lamented that the same arcane phrase ("the size of a small Fox Terrier"), when most readers would be not be closely familiar with size of a Fox Terrier. Gould concluded that Henry Fairfield Osborn had described it that way in a widely distributed pamphlet. The reasons for this comparison are unclear, but Gould proposes that Osborn, a keen fox hunter, could have made a natural association between horses and the dogs that accompany them.[3] Eohippus was approximately 12 inches high at the shoulder,[4] comparable to a Fox Terrier, which is up to 13 inches high at the shoulder.[5]
See also
References
- ^ MacFadden, B. J. (March 18, 2005). "Fossil Horses--Evidence for Evolution". Science. 307 (5716): 1728–1730. doi:10.1126/science.1105458. PMID 15774746.
- ^ Froehlich, D. J. (2002). "Quo vadis eohippus? The systematics and taxonomy of the early Eocene equids (Perissodactyla)". Zoological Journal of the Linnean Society. 134 (2): 141–256. doi:10.1046/j.1096-3642.2002.00005.x.
- ^ a b Gould, S.J. (1991). "Essay 10: The case of the creeping fox terrier clone". Bully for Brontosaurus: Reflections in Natural History. W.W. Norton & Co.
- ^ "Hyrocotherium (Eohippus)". University of Guelph.
- ^ "Fox Terrier (Vital Stats)". DogTime.