Plesiosaurs (PLEEZ-ee-oh-sawrs) were meat-eating reptiles that came in many shapes and sizes. But they all had long, flat flippers. And they all breathed air.

Kronosaurus

(CROH-no-SAWR-us)

The head of Kronosaurus was more than nine feet long. This giant reptile used its strong muscles to swim fast!

Elasmosaurus

(ee-LAZZ-moh-SAWR-us)

The neck of an Elasmosaurus was longer than a giraffe is tall. This creature had the most neck bones of any animal ever discovered: 72!