Mastodonsaurus was a large-headed temnospondyl that belonged to a group of advanced, mostly Triassic animals called capitosaurs. It had a short, massive body, stout limbs, a short tail, and a long-jawed powerful skull. Two triangular tusks pointed up from near the tip of its lower jaw. When the jaws closed, these slotted through openings on the palate and projected through the top of the skull. The fossils of some smaller temnospondyls bear tootgh marks made by Mastodonsaurus-like animals. It probably also ate fish, as well as land-living animals, such as small archosaurs.

Temnospondyls | Triassic animals