Stupendemys

Stupendemys Temporal range: late Miocene – early Pliocene 6 to 5 mya
Stupendemys geographicus at the AMNH
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Subphylum:	Vertebrata
Superclass:	Tetrapoda
Class:	Reptilia
Subclass:	Anapsida
Order:	Testudines
Suborder:	Pleurodira
Family:	Podocnemididae
Genus:	Stupendemys Wood, 1976

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.

Stupendemys's carapace measured over 1.80 m (5.9 ft) 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.