The Leatherback sea turtle, (Dermochelys coriacea), sometimes called the lute turtle, is the largest known of all living turtles (as well as the largest known extant sea turtle) and is the fourth largest known modern reptile behind three crocodilians. It is the only living species in the genus Dermochelys. It can easily be differentiated from other modern sea turtles by its lack of a bony shell. Instead, its carapace is covered by skin and oily flesh. The leatherback sea turtle is the only extant member of the family Dermochelyidae.