Eohippus is small fossil proto-horse. It is an extinct genus of small equid ungulates. The only species is E. angustidens, which was long considered a species of Hyracotherium. Its remains have been found in North America and date to the early Eocene (48–56 million years ago).
Temporal range: early Eocene
|National Museum of Natural History, Washington, D.C.|
- MacFadden B.J. 2005. "Evolution: Fossil horses--evidence for evolution. Science 307 (5716): 1728–1730. 
- 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. 
- Singer, Ben (May 2005). A brief history of the horse in America. Canadian Geographic Magazine. Archived from the original on 2012-01-07. Retrieved 22 December 2017.