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.
Asinus
Asinus is a subgenus of "Equus" (single-toed (hooved) grazing animal) that encompasses several subspecies of the Equidae commonly known as asses, characterized by long ears, a lean, straight-backed build, lack of a true withers, a coarse mane and tail, and a reputation for considerable toughness and endurance.