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a family of reptiles of the order Trionychoi-dae. Members of the family measure approximately 1 m in length and have three claws on each extremity. The plastron consists of several interlocking parts and does not unite with the carapace. The Trionychidae are the only turtles in which the reduced bony base of the shell is covered by soft skin, which enables them to supplement pulmonary respiration with cutaneous respiration.
There are seven genera with 22 species that inhabit the fresh waters of South and East Asia, New Guinea, Africa, and North America. In the USSR, the spiny soft-shelled turtle, whose shell measures approximately 30 cm long, is found in the Amur River basin. Trionychids are highly mobile predators.