Equus francisci

Equus francisci
Temporal range: 4.9–0.011 Ma

Blancan to Rancholabrean

Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Perissodactyla
Family: Equidae
Genus: Equus
Species: E. francisci
Binomial name
Equus francisci
Hay, 1915
  • Equus achates
  • Equus arrelanoi
  • Equus calobatus
  • Equus quinni
  • Equus tau

Equus francisci is an extinct species of Equus (the genus that includes the horse) which was native to North America.[1] Specimens of E. francisci have been found from northern Texas to southern South Dakota and in Alberta, Canada.[1] Evidence shows this species to have evolved in North America.[2]

The species Equus francisci was originally described in 1915. The same year a separate species was described from a limb bone as Equus calobatus by Troxell. This species was found in the Irvingtonian terrestrial horizon in the Tule Formation of Rock Creek, Texas. Equus calobatus is considered distinct from E. francisci on the basis of its significantly larger size, as measured from metapodials.[3] Equus arrelanoi and Equus quinni were synonymized with Equus tau in 1980. Equus tau was, in turn synonymized with E. francisci in 1989.[1] The species Equus achates was named by Hay and Cook in 1930 and synonymized with E. francisci in 1995.[1]


  1. 1 2 3 4 The Paleobiology Database.
  2. Weinstock, Jaco et al. (2005). "Evolution, Systematics, and Phylogeography of Pleistocene Horses in the New World: A Molecular Perspective" PLoS Biol 3(8): e241 doi:10.1371/journal.pbio.0030241.
  3. Scott, Eric (2004). "Pliocene and Pleistocene horses from Porcupine Cave", Biodiversity Response to Environmental Change in the Middle Pleistocene: The Porcupine Cave Fauna from Colorado, ed. A.D. Barnosky, University of California, p. 264-279.
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