Class Mammalia
Order Perissodactyla
Family Equidae
Equus and Plesippus—One-toed Horses // Haringtonhippus—New World Stilt-legged Horses // Hippidion—Hippidion Horses // Nannippus—Gazelle-horses
Although horses had most of their evolutionary history in North American, occasionally sending emigrants to Eurasia and South America, North American diversity had decreased to several genera by the beginning of the Pleistocene: Equus, Plesippus (often placed as a subgenus of Equus), Nannippus, Haringtonhippus, and possibly Hippidion. Nannippus apparently was extinct by 2.2 mya (Morgan and Lucas 2003). Cf. Hippidion occurred in the Blancan, and Plesippus (or Equus [Plesippus]) was essentially Blancan to perhaps into the Irvingtonian; Equus and Haringtonhipppus lasted to the great megafaunal extinction at the end of the Pleistocene.
Literature.
Heintzman et al. 2017, Morgan and Lucas 2003.
Last Update: 8 Jul 2018