Liopleurodon, big Jurassic plesiosaurs

This 7 January 2019 video says about itself:

Liopleurodon (meaning ‘smooth-sided teeth’) 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 (c. 160 to 155 mya).

Liopleurodon … 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 6.4 metres (21 ft) in length. Liopleurodon fossils have been found mainly in England and France. Fossil specimens that are contemporary (Callovian) with those from England and France referable to Liopleurodon are known from Germany. Currently, there are two recognized species within Liopleurodon. Only L. ferox is known from more or less complete skeletons.