Sea turtles (Superfamily Chelonioiea) are turtles found in all the world's oceans except the Arctic Ocean. There are seven living species of sea turtles: flatback, green, hawksbill, Kemp's Ridley, leatherback, loggerhead and olive ridley. The East Pacific subpopulation of the green turtle was previously classified as a separate species, the black turtle, but DNA evidence indicates that it is not evolutionarily distinct from the green turtle. All species except the leatherback are in the family Cheloniidae; the leatherback belongs to the family Dermochelyidae and is its only member.