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.
Equus (play) produced as a large-format artist's book by the Old Stile Press, with images and an afterword by the British artist Clive Hicks-Jenkins, in 2009. "Equus" was revived in San Jose, California, in March 2011 at City Lights Theater Company. This production, featuring actors Sean Gilvary as Alan Strang and Steve Lambert as Martin Dysart, received rave reviews. "The Mercury News" labeled Gilvary and Lambert as "haunting," stating Gilvary "...exposing emotions and epidermis, rides bareback in every sense. He gradually manages to make a rather unattractive young creature seem not only sympathetic but redeemable while retaining his hostility and humanity." Starkinsider