Liopleurodon

Liopleurodon is a genus of large, carnivorous marine reptile belonging to the Pliosauroidea, a clade of short-necked plesiosaurs. The two species of Liopleurodon lived during the Callovian stage of the Middle Jurassic Period. It was the apex predator of the Middle to Late Jurassic seas that covered Europe. The largest species, L. ferox, is estimated to have grown up to 6.39 metres in length.