Archelon was enormous marine turtle (a chelonian), the biggest that has ever lived. Archelon belonged to the Class Reptilia (reptiles), Order Chelonia (turtles, tortoises and terrapins), Suborder Cryptodira, Family Protostegidae (sea turtles from the belatedly Cretaceous age with flippers and least shells), Genus Archelon.
It was a ocean going turtle, related to current day Leatherback Sea Turtles. It measured more than 13.5 feet (4 metres) long and about 16 feet wide from flipper to flipper. Archelon's shell was not similar to that of modern-day turtles, it did not have the many shell bones of modern-day tortoises. Archelon's back probably had a leathery covering or horny plates over a bony framework on its back. Archelon had a wide, flattened shell, paddle-like legs, a long, narrow head, weak jaws and a small, pointed tail. Archelon had a solidly-roofed skull with no opening (apart from for eyes and nostrils). It swam using its paddle-like flippers and legs. The live weight of an Archelon is expected at more than 4,500 pounds (2200 kilograms).
Archelon was a (meat-eater) carnivore. Because of its very fragile jaws and toothless beak, it may have eaten jellyfish as its major diet. Archelon lived in the seas in what is now North America; fossils have been established in Kansas and South Dakota, USA. Its fossils date to 70 million years previously in the Cretaceous period, when a shallow ocean covered most of central North America.
Archelon, other turtles (chelonians) and reptiles may have descended from captorhinids, prehistoric anapsids that lived during the Early Carboniferous age, about 340 million years previously and went extinct at the end of the Triassic period, about 250 million years back.
Scientific Classification:
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
Order: Testudines
Suborder: Cryptodira
Family: Protostegidae
Genus: Archelon
Binomial name: Archelon ischyros