Equus (genus) 54 million years ago (Mya). These animals had three toes on the hind feet and four on the front feet with small hooves in place of claws, but also had soft pads.<ref name="doi10.1126/science.1105458"></ref> Equids developed into larger, three-toed animals (e.g. "Mesohippus") during the Oligocene and Miocene. From there, the side toes became progressively smaller through the Pleistocene until the emergence of the single-toed "Equus". The genus "Equus", which includes all extant equines, is believed to have evolved from "Dinohippus", via the intermediate form "Plesippus". One of the oldest species is "Equus simplicidens", described as zebra-like with a donkey-like head shape.
Australopithecus africanus of the Witwatersrand in Johannesburg, South Africa, became interested in fossils found at a limestone quarry at Taung near Kimberley, South Africa in 1924. The most promising of these was a skull of an odd ape-like creature presenting human traits at the eye orbits, teeth, and, most importantly, the hole at the base of the skull over the spinal column (the foramen magnum); its placement indicated a human-like upright posture and implied a high probability that this hominid-to-hominin primate had achieved bipedal, as opposed to quadrupedal locomotion. Dart assigned the specimen the name "Australopithecus africanus" ("southern ape of Africa"); it