The seven species of marine turtle found today developed from a single, unique group that separated from other turtle species over 100 million years ago. This group then split into two families, Cheloniidae and Dermochelyidae, that represent all sea turtles in the world today.
Six of the seven species of marine turtles are classified within the hard-shelled Cheloniidae:
- Caretta caretta (loggerhead)
- Chelonia mydas (green turtle)
- Eretmochelys imbricata (hawksbill)
- Lepidochelys kempii (Kemp’s ridley)
- Lepidochelys olivacea (olive ridley)
- Natator depressus (flatback)
The family Dermochelyidae is represented solely by the unique species Dermochelys coriacea (leatherback), which lacks the hard shell that characterizes other marine turtles.
Marine turtles can be found in every major ocean basin. While most species are found primarily in tropical and subtropical waters, individuals have been known to venture as far as the colder waters of the Arctic. For more information on the distribution and status of marine turtles visit SWOT—The State of the World’s Sea Turtles.