This is the Mastodonsaurus.

Amphibians are animals which in real life need to be moist in order to survive because they "breathe" through their skin. In Dinosaur Simulator there are only two amphibians which are temnospondyls. Oddly, they don't need to go in water to get moistness because they simply can't become dry unlike all the truly aquatic animals unrelated to the amphibians in the game.

The animals which represent amphibians in this game are currently:

The amphibians in the game are pretty weak and are not made to fight big animals, only being good at kidnapping small animals, children and small corpses. They are really bad at climbing hills because of their bad models and amphibians not being suited for climbing, though some anurans (frogs) are quite good at it. Amphibians are very rarely seen on any server due to them being weak and overshadowed by their semi-aquatic reptilian pals like Spinosaurus or Pteranodon. As an amphibian you should hide in the oceans or live near shore because most predators will view you as a quick snack. The only amphibian with skins is the Koolasuchus, having a Mayhem skin and a Mega Tail Koolasuchus. Koolasuchus is often mistaken for a crocodilian because of the phrase "suchus", but it is confirmed to be an amphibian.