Stupendemys

Stupendemys is a prehistoric genus of freshwater turtle. Its fossils have been found in northern South America, in rocks dating from the late Miocene to the very start of the Pliocene, about 6 to 5 million years ago.Bocquentin, Jean & Melo, Janira 2006. Stupendemys souzai sp. nov. (Pleurodira, Podocnemididae) from the Miocene-Pliocene of the Solimões Formation, Brazil. Revista Brasileira de Paleontologia 9(2): 187-192. PDF fulltext

Stupendemys'''s carapace measured over  in length and was also very wide. With a total carapace length of at least 11 feet (3.3 m) it was the largest turtle that ever existed, surpassing even Archelon. 

Two species have been described to date. Stupendemys geographicus from Venezuela, and Stupendemys souzai, a bit smaller and more slender, from Brazil.

 Ecology 
Its weight helped Stupendemys'' stay under water for long periods, grazing on aquatic plants. It was probably a very weak swimmer, unable to move its bulk against a swift current, and probably avoided smaller streams.

Altogether, the fauna of the time had many large herbivores and few terrestrial carnivores. The habitat was mostly low-lying rainforest that was seasonally flooded, as well as floodplains and swampland. The rivers must have been wide and slow-moving.

 References 

Category:Turtles
Category:Fossils