Temporal range: Upper Cretaceous
|Type specimen (YPM 3000) of Archelon ischyros|
Archelon was huge marine turtle (Testudines) that was the size of a car. It lived in North America 74 million years ago (Upper Cretaceous) in the epeiric inland sea called the Western Interior Seaway. Fossils have been found in Kansas and South Dakota.
This carnivore was up to 4.6 metres (15 ft) long. It had a wide, flattened shell, paddle-like legs, a long, narrow head, weak jaws, and a short, pointed tail. Probably, its only predators were the larger mosasaurs. From its beak, its own food was probably squid.
Archelon are like other turtles, had a solidly-roofed skull with no opening (except for eyes, and nostrils).