Imagine Dinosaurs's video: Pliosaurs: Liopleurodon

Liopleurodon (pronounced /ˌliːoʊˈplʊrədɑn/, meaning 'smooth-sided teeth') is a genus of large, carnivorous marine reptile belonging to the Pliosauroidea, a clade of the short-necked plesiosaurs. Two species of Liopleurodon, L. ferox and L. pachydeirus, lived during the Callovian stage of the Middle Jurassic Period (c. 160 million to 150 million years ago mya), while the third, L. rossicus, lived during the Late Jurassic. It was an apex predator of the Middle to Late Jurassic seas that covered Europe. The name of the Liopleurodon, three large, 70 mm teeth and these poor remnants were based on HE Sauvage in 1993 [1]. A tooth located near Boulogne-sur-Mer, a layer from the Callovian, Liopleurodon ferox to France, another from Charly, Liopleurodon grossouvrei to France, France discovered here in Caen, initially described as Poikilopleuron, Sauvage Liopleurodon Bucklandi). Sauvage, in his description, did not assign to a genus of reptile groups. Liopleurodon fossils have been found mainly in England and France, with one species known from Russia. Fossil specimens referrable to Liopleurodon and contemporary (Callovian) with those from England and France have been found in Germany.[2] Currently, there are three recognized species within Liopleurodon. L. ferox is well known from finds in the Callovian strata of England and France; while also from the Callovian of England is the rarer L. pachydeirus, described by Seeley as a Pliosaurus (1869).[3] L. rossicus has been found in Russia's Volgian region. The latter species was initially described by Novozhilov (1948) as belonging to Pliosaurus,[4] and is the type species of the genus Strongylokroptaphus.[5] Only L. ferox is known from more or less complete skeletons. Paleobiology 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.[6][7] Studies of the skull have shown that it could probably scan the water with its nostrils to ascertain the source of certain smells.[8] The largest known Liopleurodon skull belongs to L. ferox. It measures 7 meters but the largest specimens measure a little over 10 meters. and was originally estimated (Tarlo, 1960) to belong to an animal about 25 meters (80 feet) in length.[14] Later work (Noe, 2004) cast doubt on the model used to estimate the length of Liopleurodon, which had been based on the 5 meter skull length to body length ratio found in the famous (and morphologically similar) Kronosaurus skeleton mounted at Harvard's Museum of Comparative Zoology. Analysis of two mostly complete adult L. Ferox skeletons showed that the ratio of skull length to body length was more in the range of 1:9 or even 1:8, leading Noe to estimate that Tarlos's L. Ferox was only about 24 meters (75 feet), with a corresponding weight of about 2.5 metric tons (2.75 tons).15 (The original reconstruction of Harvard's Kronosaurus Queenslandicus is now known to have included too many vertebrae, resulting in a size estimate of ~ 40 feet as well as derivation of an erroneous skull length to body length ratio. K. Queenslandicus is now believed to have had a skull to body ratio of 1:9 and a corresponding length of about 25 meters.) A mandible on display in the Oxford University Museum of Natural History, estimated to be over 3 meters (preserved 2.875m) and to have come from a skull perhaps 3.6 meters in length, was at one time classified as Liopleurodon macromerus. (When the mandible was described, it was originally assigned to Stretosaurus (as Stretosaurus macromerus).[10] The genus Stretosaurus later became a junior synonym of Liopleurodon.[11]) However, the Oxford mandible has since been re-classified as Pliosaurus macromerus.[12] The Liopleurodon ferox depicted in the 1999 BBC television series Walking with Dinosaurs—an enormous 25 meter-long (80 feet) monster weighing up to 150 tons—is considered to be based on a reasonable estimate of L. ferox's maximum size.[16] In fairness to the program's producers, it should be noted that the 3 meter mandible of the Oxford Pliosaurus macromerus was, at the time of the series, classified as belonging to a Liopleuridon macromerus (it was not re-classified as Pliosaurus macromerus until 2003).