Prionosuchus

Prionosuchus is an extinct genus of extremely large temnospondyl amphibians from the Middle Permian (270 million years ago), fossils of which have been found in what is now Brazil.

The genus is monotypic with P. plummeri being the only species described. The archegosaurs were a group of temnospondyli that occupied the ecological niche of crocodiles and alligators during the Permian, and of which the European genus Archegosaurus is typical. The group went extinct at the end of the Permian and the niche was subsequently filled by other, new temnospondyls, later joined by reptiles such as the phytosaurs in the Triassic period.