mya) and in existence for approximately 6.7 million years.[2][3] Fossils are widespread throughout North America, being found at more than 30 sites from Florida to Alberta and Panama (Alajuela Formation
).
Taxonomy
Skull
Quinn originally referred "Pliohippus" mexicanus to Dinohippus, but unpublished cladistic results in an SVP 2018 conference abstract suggest that mexicanus is instead more closely related to extant horses than to Dinohippus.[4]
Description
Dinohippus was the most common horse in North America and like
monodactyl horse, but a 1981 fossil find in Nebraska shows that some were tridactyl.[6] The species D. leidyanus had an estimated body mass of approximately 200 kilograms (440 lb).[7]
Diet
D. mexicanus fed primarily on
C3 plants in rainforest clearings based on paired carbon and oxygen isotope analysis.[8]
^Bruce J. MacFadden: Cenozoic Mammalian Herbivores from the Americas: Reconstructing Ancient Diets and Terrestrial Communities. Annual Review of Ecology and Systematics, Vol. 31, (2000), pp. 33-59
^M. Mendoza, C. M. Janis, and P. Palmqvist. 2006. Estimating the body mass of extinct ungulates: a study on the use of multiple regression. Journal of Zoology
