DICYNODON

extinct genus of therapsid reptiles, which once were dominant mammallike land vertebrates, found in Upper Permian deposits (i.e., those roughly 245 to 258 million years old) in southern Africa, Europe, and southern Asia. The skull of Dicynodon was very long in the region behind the eye, with well-developed ridges that provided attachment for strongly developed jaw muscles. A toothless, beaklike structure was probably covered with a horny material that was also probably present in the remainder of the jaw. Small teeth occurred on some specimens, as did a pair of tusklike canine teeth, which may have been restricted to males. Dicynodon, probably herbivorous, had a massive body with strong limbs and limb girdles.