Plesiosaurs are an order of large extinct marine reptiles that lived during the Jurassic period, 201–145 million years ago, and the Cretaceous period, 145–66 million years ago. The name comes from the Greek plesios – “near to” and sauros – “reptile”. Plesiosaurs are distinguished by a small head, a very long, slender neck, a large body, a short tail and two pairs of large, elongated flippers.
The plesiosaur teeth are simple, long and thin, slightly curved and circular in section. The tip is sharp, and their entire surface exhibits fine striations.
Plesiosaurs reached lengths of up to 15 meters and fed on cephalopods, fish, and other creatures; their teeth were specialized for catching fish. They moved through the water using fins, and their long neck may have been used for guidance while hunting. Plesiosaurs gave birth to live young in the water, like sea snakes. It is possible that the young lived in estuaries until they grew large enough to swim out to sea.
