Archelon means “large turtle”, and that is exactly what it was, in fact it was the largest turtle in history. Living in the late Cretaceous, ArchElon could reach up to 4.5 metres long and live to over a 100 years old. 
Archelon could not match the other marine reptiles in their speed, but its blade-like beak was a fearsome weapon, this turtle would have been able to crush through ammonite shell and the bones of other sea-dwellers. 
Despite its enormous size, Archelon’s anatomy is not unlike that of modern turtles. It possessed huge flippers to propel through the water for long periods of time and occasionally Archelon would rest on land. To venture onto the land would have been quite a task due to its size, so it is commonly thought that Archelon would rest on the shore before lumbering back into the water. 
With such a large shell comes a great amount of weight, as Archelon was most likely a surface hunter, this was not practical. Instead, the shell was not solid and was instead compiled of bony ribs with a hard, thick layer of skin stretched over it, not quite a shell after all. 

Although Archelon looks as though it could be a monster of the seas today, during the cretaceous it was an easy target. Despite its size it had very little defences, with no shell, the inability to withdraw its flippers and head made it an easy option for predators. Many fossils of Archelon show one or two missing flippers, an Archelon flipper was clearly a popular snack. 
Fossils of this prehistoric giant are most often found in north America, specimens have ranged from 4-5 metres in length and alive would have weighed an estimated 2200 kg. The most famous specimen was discovered in South Dakota in almost pristine condition. With its head bowed and flippers folded in, the animal was though to have died whilst hibernating on the sea floor. 
The cretaceous met the end of Archelon and everything living alongside it. A meteor hurtling to Earth plunged the world into a cold darkness, cooling the oceans and suffocating land and sea. All was not lost for this giant turtle, Archelon’s closest relative today is the leatherback sea turtle. 

ARCHELON