a family of reptiles of the order Pleurodira. The neck is relatively short and can be retracted sideways under the shell. The plastron has 11 osteal plates. Pelomedusidae live in rivers and lakes, feeding on invertebrates, small fish, amphibians, and fruit. There are 14 species, making up three genera: Pelomedusa (one African species), Pelusios (five species, distributed in Africa, on Madagascar, and on the Masca-rene and Seychelles islands), and Podocnemys (eight species, distributed in South America and on Madagascar).
Podocnemys expansa, a large tortoise, was once particularly numerous in the tropics of South America. The females weigh up to 50 kg and have shells reaching a length of 77 cm; the males are much smaller. In one laying, more than 100 eggs are deposited in the sand. Because the eggs have been eaten for food or destroyed for their oil, P. expansa is nearly extinct.