The leatherback sea turtle (Dermochelys coriacea), sometimes called the lute turtle, is the largest of all living turtles and is the fourth heaviest 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. Dermochelys coriacea is the only extant member of the family Dermochelyidae.