Equus (genus) Equus (genus) Equus is a genus of mammals in the family Equidae, which includes horses, donkeys, and zebras. Within Equidae, "Equus" is the only recognized extant genus, comprising seven living species. The term equine refers to any member of this genus, including horses. Like Equidae more broadly, "Equus" has numerous extinct species known only from fossils. The genus most likely originated in North America and spread quickly to the Old World. Equines are odd-toed ungulates with slender legs, long heads, relatively long necks, manes (erect in most subspecies), and long tails. All species are herbivorous, and mostly grazers, with simpler
Australopithecus africanus and STS 71), but also presents primitive features including ape-like, curved fingers adapted to tree climbing. Instead of it being a direct ancestor of later hominins and thereby of humans, some researchers believe that "A. africanus" evolved into "Paranthropus", and specifically that "P. robustus" descended from "A. africanus". Both "P. robustus" and "A. africanus" crania seem very alike despite the more heavily built (robust) features of "P. robustus", which, like those of the modern gorilla, are adaptations for heavy chewing. "A. africanus", on the other hand, had a cranium which quite closely resembled that of a modern chimpanzee; yet both