Lystrosaurus

Lystrosaurus (/ˌlɪstroʊˈsɔːrəs/; 'shovel lizard'; proper Greek is λίστρον lístron ‘tool for leveling or smoothing, shovel, spade, hoe’) was a herbivorous genus of Late Permian and Early Triassic Period dicynodont therapsids, which lived around 250 million years ago in what is now Antarctica, India, and South Africa. Four to six species are currently recognized, although from the 1930s to 1970s the number of species was thought to be much higher. They ranged in size from a small dog to 2.5 meters long.[2][better source needed]

Being a dicynodont, Lystrosaurus had only two teeth (a pair of tusk-like canines), and is thought to have had a horny beak that was used for biting off pieces of vegetation. Lystrosaurus was a heavily built, herbivorous animal, approximately the size of a pig. The structure of its shoulders and hip joints suggests that Lystrosaurus moved with a semi-sprawling gait. The forelimbs were even more robust than the hindlimbs, and the animal is thought to have been a powerful digger that nested in burrows.

Lystrosaurus survived the Permian-Triassic extinction, 252 million years ago. In the Early Triassic, they were by far the most common terrestrial vertebrates, accounting for as many as 95% of the total individuals in some fossil beds.[3]Researchers have forwarded various hypotheses for why Lystrosaurus survived the extinction event and prospered in the early Triassic.