2022 Liopleurodon Prehistoric Life 1oz Silver Bullion Coin

Liopleurodon, meaning ‘smooth-sided teeth’ is an extinct genus of large, carnivorous marine reptile belonging to a clade of short-necked pliosaurid plesiosaurs. The two species of Liopleurodon lived from the Middle to the Late Jurassic Period (c. 166 to 155 MYA). It was the apex predator of the seas that covered Europe. The largest species, L. ferox, is estimated to have grown up to 6.6 metres in length, but could have been larger.

Liopleurodon ferox first came to the public attention in 1999 when it was featured in an episode of the BBC television series Walking with Dinosaurs, which depicted it as an enormous 25 m long and 150 t predator; this was based on very fragmentary remains, and considered to be an exaggeration. Modern estimates have the length at circa 7 m, with exceptional specimens hitting 10 m, and around 3 tonnes.

Four strong paddle-like limbs suggest that Liopleurodon was a powerful swimmer. Its four-flipper mode of propulsion is characteristic of all plesiosaurs. A study involving a swimming robot has demonstrated that although this form of propulsion is not especially efficient, it provides very good acceleration—a desirable trait in an ambush predator. Studies of the skull have shown that it could probably scan the water with its nostrils to ascertain the source of certain smells.