Equidae
Equidae (sometimes known as the horse family) is the taxonomic family of horses and related animals, including the extant horses, donkeys, and zebras, and many other species known only from fossils. All extant species are in the genus "Equus". Equidae belongs to the order Perissodactyla, which includes the extant tapirs and rhinoceros, and several extinct families.
Onager
The onager (; "Equus hemionus"), also known as hemione or Asiatic wild ass, is a species of the family Equidae (horse family) native to Asia. A member of the subgenus "Asinus", the onager was described and given its binomial name by German zoologist Peter Simon Pallas in 1775. Five subspecies have been recognized, one of which is extinct.