Prionosuchus

Prionosuchus is a genus of extremely large temnospondyl amphibians from the Middle Permian (270 million years ago). Its remains were found in Brazil.

Description
The fragmentary remains of this animal were found in the Parnaíba Basin of northeast Brazil.Price L.I.  1948. Um anfibio Labirinthodonte da formacao Pedra de Fogo, Estado do Maranhao. Ministerio da Agricultura, Departamento Nacional da Producao ineral Divisao de Geologia e Mineralogia, Boletim n. 124, p. 7-32. With an estimated length of 9 m (30 ft), Prionosuchus is the largest amphibian ever found.
It had an elongated and tapered snout, numerous sharp teeth, long body, short legs, and a tail adapted for swimming. 

Cox and Hutchinson re-evaluated Prionosuchus in 1991 and thought it was synonymous with the genus Platyoposaurus from Russia.Cox C.B. and Hutchinson P. 1991. Fishes and amphibians from the Late Permian Pedrado Fogo Formation of northern Brazil. Palaeontology, 34: 561-573 However, Platyoposaurus had a total length of only 2.5 meters (8.2 ft), which suggested that the two animals were at least different species. The age of the sediments suggested the two were not comtemporaries.Mussa D & Coimbra AM., 1987, Novas perspectivas de comparação entre as tafofloras permianas (de lenhos) das Bacias do Parnaíba e do Paraná. X Congresso brasileiro de Paleontologia. Rio de Janeiro. Anais da Academia Brasileira de Ciencias, 2: 901-922.Caldas E.B. et al 1989. Nota sobre a ocorrência de uma floresta petrificada de idade permiana em Teresina, Piauí. Bol IG-USP, Publ Esp 7: 69-87. Most paleontologists consider Prionosuchus as a valid genus.

Paleoecology
Prionosuchus lived in a humid and tropical environment as indicated by the petrified forest of the Pedra do Fogo formation in which the fossil was found. The strata of siltstones, shales and limestones were deposited in lagoonal and riverine environments.Schobbenhaus C. et al 1984. Geologia do Brasil. p501 Other animals discovered in the same rocks include fish (primitive sharks, palaeoniscids, and lungfish) and amphibians.

Its general appearance was similar to a modern crocodile, such as the gharial. It probably had a similar lifestyle as an ambush aquatic predator feeding on fish and other aquatic animals.

It was one of a group known as the Archegosaurs.Carroll R.L. 1988. Vertebrate paleontology and evolution. W.H. Freeman. The archegosaurs were a group of temnospondyls that occupied the ecological niche of crocodiles and alligators during the Permian. The smaller European genus Archegosaurus is typical. The group went extinct at the end of the Permian. In the Triassic, the ecological niche was filled by other temnospondyls and by reptiles such as the phytosaurs.

References

Category:Temnospondyls
Category:Fossils