Horse
Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus".
Even-toed ungulate
Molecular findings and morphological indications suggest that artiodactyls are paraphyletic to cetaceans and together form the monophyletic taxon Cetartiodactyla. Modern nomenclature divides Cetartiodactyla in five subordinate taxa: camelids (Tylopoda), pigs and peccaries (Suina), ruminants (Ruminantia), hippos (Ancodonta), and whales (Cetacea).