Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class Reptilia
Subclass Diapsida
Order Plesiosauria
Suborder Pliosauroidea
Family Pliosauridae
Genus Pliosaurus
1st Species Pliosaurus brachydeirus
2nd Species Pliosaurus brachyspondylus
3rd Species Pliosaurus macromerus
4th Species Pliosaurus rossicus
Other attributes
Time Range 155.7-147 mya
Location United Kingdom, Norway, France, Russia
Name Meaning More reptile
Physical Dimensions 9.7 meters for P.macromerus; 9.7 meters for P.rossicus; 8.8 meters for P.funkei; 7.6 meters for P.carpenteri; 7.4 meters for P.kevani
Weight 9 tonnes for P.macromerus; 8.7 tonnes for P.rossicus; 6.6 tonnes for P.funkei; 4.2 tonnes for P.carpenteri; 4 tonnes for P.kevani
Dietary Classification Carnivore

Pliosaurus is a pliosaurid plesiosaurian reptile from the Late Jurassic of the United Kingdom, Norway, France, and Russia. It was officially named in 1842 by Richard Owen. It was the biggest Jurassic marine predator (and by extension, the largest Jurassic predator), and was thought to be a gigantic species of Plesiosaurus before finally being described as its own genus.


Pliosaurus had a passing resemblance to its cousins, Plesiosaurus and Cryptoclidus; it was a massive reptile with a bulky body, 4 flippers, and a short tail. However, it differed from them in a few notable ways; whereas Plesiosaurus and Cryptoclidus had long, snake-like necks with small heads, Pliosaurus had a short neck with a huge, crocodile-like head that took up 1/4 of its total body length; as well as this, some Pliosaurus species like Pliosaurus funkei had extremely long flippers comparable in length to their torsos. Its body would have been covered in scaly skin.


Pliosaurus was a predator, preying on turtles, ichthyosaurs, thalattosuchians, smaller plesiosaurs, and even large Leedsichthys individuals. Its large teeth had knife-like serrations from back to back, and were designed for crushing bone.


Pliosaurus was a large plesiosaur that ruled over the Jurassic oceans as apex predator, preying on smaller reptiles as big as Kimmerosaurus to large, pelagic behemoths like the filter-feeding fish Leedsichthys. Its massive jaws had taken up 1/4 of its body length, and were adorned with big, serrated teeth, which were used for slicing into the flesh of its prey; combined with a powerful bite, this would have made Pliosaurus a ruthlessly efficient hunter. When feeding from carcasses, it would grab a hold of them before tilting its head to the side in order to tear chunks of flesh off of them; it shared this feeding style with many semi-aquatic crocodylomorphs (including its contemporaries, Dakosaurus and Plesiosuchus). An interesting thing to note about Pliosaurus is that it had a snout that was sensitive to touch, which was most likely used for detecting the movements of aquatic prey even when the plesiosaur wasn't able to see them, allowing it to locate them much more easily; it is not unlikely that other pliosaurs had sensitive snouts as well, but so far, the only other evidence for sensitive snouts in prehistoric reptiles is found in the giant theropod dinosaurs like Neovenator, Baryonyx, Spinosaurus, and Daspletosaurus.

In popular cultureEdit

Pliosaurus was featured in the 4th episode of the 2011 documentary Planet Dinosaur, where the recently discovered Norwegian species, Pliosaurus funkei, was nicknamed "Predator X" and identified as a 15 meter long, 45 tonne carnivore; although this oversizing was quite tame compared to the Liopleurodon from Walking with Dinosaurs, it was still drastic and, since its birth, very commonly repeated throughout the history of the media. In the episode itself, it attempts to hunt down a small squadron of Kimmerosaurus, failing when the cryptoclidids reach their nursery and are provided safety from the pliosaurid's jaws; however, the giant carnivore eventually gets its long-desired meal when it launches an ambush on a lone Kimmerosaurus.

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