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a family of reptiles of the order Pleurodira. The Chelidae are distinguished from the other representatives of the order (the Pelomedusidae) by their particularly long neck and a number of other features. There are approximately 30 species, belonging to ten genera, distributed in the rivers and lakes of South America, Australia, and New Guinea. The Australian snake-necked turtle (Chelodina longicollis) has a flat oval carapace. It is common in the rivers of southern Australia and feeds mainly on small fish. In January the female lays 15 to 25 eggs. The species of Hydro medusa and the matamata are characteristic of South America.