What are the most widely distributed marine reptiles?

Sea turtles are the most distributed marine reptiles. Sea turtles, sometimes called marine turtles, are reptiles of the order Testudines. The seven extant species of sea turtles are: the green, loggerhead, Kemp's ridley, olive ridley, hawksbill, flatback, and leatherback. The majority of a sea turtle's body is protected by its shell.

The turtle's shell is divided into two sections: carapace (the dorsal portion) and plastron (the ventral portion). The shell is made up of smaller plates called scutes. The leatherback is the only sea turtle that does not have a hard shell. Instead, it bears a mosaic of bony plates beneath its leathery skin.