Mastodonsaurus giganteus was a large temnospondyl from Europe that belonged to a group of mostly Triassic amphibians,capitosaurids. It lived 210 million years ago. The length of the animal was about 5 meters (16.4 feet) .
Mastodonsaurus was an aquatic animal which hardly ever left water. It inhabited swampy pools and ate mainly fish and possibly land-living animals like small archosaurs.