"Grandfather" of a modern horse - the last significant link in the horse evolution change before arriving at Equus was Pliohippus. This was the first singled toe, or hoofed, horse. This Equss prototype was about 12 hands at the shoulder and had strong leg ligaments to add to his speed and power.
Pliohippus had 19 pairs of ribs.
Fossils of Parahippus are found at many early Miocene localities in the Great Plains and Florida.