Kingdom Animalia
Phylum Chordata
Superclass Tetrapoda
Class Reptilia
Subclass Diapsida
Order Plesiosauria
Suborder Pliosauroidea
Family Pliosauridae
Genus Liopleurodon
1st Species Liopleurodon ferox
2nd Species Liopleurodon pachydeirus
Other attributes
Time Range 161.3-157.1 mya
Location United Kingdom, France, Germany
Name Meaning Smooth-sided tooth
Physical Dimensions 5.5 meters long
Weight 2.2 tonnes
Dietary Classification Carnivore

Liopleurodon is a pliosaurid plesiosaurian reptile from the Late Jurassic of the United Kingdom, France, and Germany. It was named in 1873 by Henri Émile Sauvage. It is one of the most studied plesiosaurs, and is often times mentioned to be the biggest marine reptile of all time (when in reality, it was far from the biggest).


Liopleurodon was a plesiosaur with a bulky body, 4 flippers, and a short tail with a small fin on its end. However, like most pliosaurids, and unlike most other plesiosaur families, it had a short neck and a large head with massive jaws. Its body would have been covered in scaly skin.


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


Even as a relatively small pliosaur, Liopleurodon established itself as the apex predator of its environment, preying on anything from small animals such as Leptolepis and Hybodus to even smaller individuals of the filter-feeding fish Leedsichthys. With large jaws taking up 1/4 of its total body length, it had a powerful bite, which would allow it to make short work of small-midsized prey items. As well as this, a study done on its nostrils had led to the theory that it had a directional sense of smell; this could allow it to detect hidden prey, and even sense the blood of kills made by other predators (similar to modern sharks). A study involving a Liopleurodon-like swimming robot seemed to prove that the plesiosaur was not an efficient long-distance swimmer, but could gain a sudden burst of speed to dash at its chosen target; however, this conclusion was made when people thought it propelled itself by moving its front and back flippers up and down at different times instead of moving all its flippers at the same time.

In popular cultureEdit

Liopleurodon was first introduced to the public through the 3rd episode of the 1999 documentary Walking with Dinosaurs, where it is featured as an enormous (blue whale-sized), bloodthirsty apex predator that preys on anything it sees, from the beach-combing theropod Eustreptospondylus to the bathypelagic ichthyosaur Ophthalmosaurus; since the real Liopleurodon only measured 4.3-5.5 meters and weighed 1-2.2 tonnes (as opposed to the 25 meter, 150 tonne leviathan that haunted the documentary), this was the most dramatic, egregious, and ignominious oversizing of a prehistoric animal in the history of the media. Despite being debunked time and again, the colossal plesiosaur appeared again in another, similar documentary, Chased by Sea Monsters, where it feasts on a dying Leedsichthys (also oversized); since then, this depiction has been perpetuated in every major piece of media containing Liopleurodon.

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