Skull of a primitive reptilian in a group that may have given rise to turtles.

When scientists first described this fossil, it was thought to be a labyrinthodont amphibian. Further analysis, however, now has led to the view that although in its flattened nature it did bear a strong resemblance to the labyrinthodonts, it was a reptile, and a close ally of turtles. Certainly advanced labyrinthodonts and primitive reptiles show many similarities for indeed some labyrinthodonts that were the ancestors of reptiles.

Lanthanosuchus was adapted to life in warm saline pools, which were abundant in parts of Tatarstan in the Late Permian. There it may have fed on organisms including crabs and insects. It probably was an ambush predator that fed off the bottom of lakes and streams. Notches in the skull below the eye sockets may have housed special saline-excretory glands that dumped excess amounts of salts built up in Lanthanosuchus as a result of its surroundings.