Lystrosaurus

Lystrosaurus is an extinct genus of herbivorous dicynodont therapsid from the late Permian and Lower Triassic epochs (about 250 million years ago).

Lystrosaurus Temporal range: Upper Permian–Lower Triassic, 255–250 mya
Lystrosaurus hedini skeleton exposed at the Natural history museum of Zürich
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Clade:	Synapsida
Clade:	Therapsida
Suborder:	†Anomodontia
Clade:	†Dicynodontia
Family:	†Lystrosauridae
Genus:	†Lystrosaurus Cope, 1870
Species
List L. murrayi (Huxley, 1859) (type) L. declivis (Owen, 1860) L. curvatus (Owen, 1876) L. maccaigi Seeley, 1898

It lived in what is now Antarctica, India, China, Mongolia, Russia and South Africa. Four to six species are known. They ranged in size from that of a small dog to 2.5 meters long.^[1]

Lystrosaurus survived the Permian-Triassic extinction event, 252 million years ago. In the Lower Triassic, they were the most common terrestrial vertebrates. In some fossil beds they make up as many as 95% of the individuals.^[2] Researchers have offered various ideas for why they survived the extinction and thrived in the early Triassic.