Mosasaurus was a genus of large aquatic carnivore from the Late Cretaceous about 70-66 million years ago. Mosasaurus gave its name to a group of marine lizards - Mosasaurs. Mosasaurus means 'Meuse Lizard', referring to the river near which it was first found. It fed on such prey as seabirds, sharks, large fish, plesiosaurs and even other mosasaurs.