African wild ass (Equus)" which diverged ~4.8 (3.2–6.5) million years ago. Different authors consider the African wild ass and the domesticated donkey one or two species; either view is technically legitimate, though the former is phylogenetically more accurate. The species name for the African wild ass is sometimes given as "asinus", from the domestic donkey, whose specific name is older and usually would have priority. But this usage is erroneous since the International Commission on Zoological Nomenclature has conserved the name "Equus africanus" in Opinion 2027. This was done to prevent the confusing situation of the phylogenetic ancestor being taxonomically included in its
Equus lambei of the modern wild horse, including the domestic horse, "Equus caballus". Controversy still surrounds "E. lambei" and the divergence of other similar extinct horse species. Through examinations of the bones and teeth of "Equus lambei", many similarities can be seen with the modern horse "Equus caballus". There is also a strong resemblance to "E. lambei" in the metapodials of "E. caballus przewalskii" and the phalanges of "E. caballus lenensis" "." Metrical and morphological studies of horse teeth from the Bluefish Caves confirm the close similarity between "Equus lambei" with wild and domestic horses alive today. "E. lambei" is a "caballus"