An Ultimate Guide to Liopleurodon: The Smooth-Sided Tooth

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Name Meaning“Smooth-sided tooth”HeightN/A
Pronunciationli-o-PLEU-ro-donLength5-7 meters (16-23 feet)
EraMesozoicMiddle-Late JurassicWeight1-1.85 tons (2200-3700 lbs)
ClassificationSauropterygia, Plesiosauria & PliosauridaeLocationEurope

Liopleurodon Pictures

Liopleurodon | MR1805 via iStock

The Liopleurodon

Gage Beasley Prehistoric's Liopleurodon Concept
Gage Beasley Prehistoric’s Liopleurodon Concept

The Jurassic period is popularly called the age of the dinosaurs because of how prevalent these animals were at that time.

Still, other prominent animals ruled this age, and one of them was the Liopleurodon.

Liopleurodon belonged to a group of short-necked pliosaurid plesiosaurs and was a giant carnivorous marine reptile.

Otherwise called “smooth-sided tooth,” this now-extinct reptile was an apex predator that roamed the oceans between the Middle Jurassic and Late Jurassic periods.

The first fossils of this ancient creature were discovered in 1873 in the Boulogne sur Mer region of France.

Fossilized tooth of Liopleurodon
Fossilized tooth of Liopleurodon | Madzia via Wikipedia CC BY-SA 4.0

Each tooth was about three inches long and had no other identifying characteristics.

After receiving these fossils for examination, Henri Émile Sauvage, a paleontologist, named them the Liopleurodon ferox.

This name was assigned to this creature primarily because of the shape of the teeth. Another fossil was found in another area in France, which was named L. grossouvrei. 

More bones were recovered in other areas in France, and although they were initially categorized under the genus Poikilopleuron, Sauvage finally classified them under Liopleurodon.

Liopleurodon remains have also been found in and around Germany and England.

Gage Beasley's Prehistoric Shirt Collection
Gage Beasley’s Prehistoric Shirt Collection
Gage Beasley's Prehistoric Plush Collection
Gage Beasley’s Prehistoric Plush Collection

Liopleurodon’s massive size made it an apex predator while it was extant. It was fully aquatic and also a great hunter.

There’s more to this large creature that ruled alongside dinosaurs in the Jurassic era.

From its physical characteristics to its behavior, diet, and more, it is evident that the Liopleurodon was a formidable animal.

This article focuses on the features of this prehistoric animal, as well as other essential details about its existence.

Physical Characteristics

Liopleurodon on the hunt in the shallow seas
Liopleurodon on the hunt in the shallow seas | MR1805 via iStock

Although scientists once exaggerated the size of the Liopleurodon, they have now settled for a more reasonable size.

Still, since there are only a few postcranial fossils to work with, it is almost impossible to provide the accurate size of this reptile.

This does not negate that the Liopleurodon was one of the largest animals about 160 million years ago.

According to paleontologists, pliosaurs’ skulls accounted for one-seventh of their bodies.

This made them conclude that the Liopleurodon had an average length of 16-23 feet.

Gage Beasley Prehistoric’s Liopleurodon Size Comparison Chart

They also believe that they weighed 2200-3700 pounds, sometimes more than that, making this species one of the world’s biggest and strongest predatory animals.

Liopleurodon also had powerful paddle-like four-flipper limbs that are common among plesiosaurs.

These flippers were primarily used for maneuvering and steering in the water, making them great swimmers, regardless of their vast size.

Liopleurodon had all the trappings of a great hunter.

That includes the four large flipper limbs and a short neck.

This short neck made it easy for them to tear off huge chunks of flesh.

They also possessed massive jaws that contained sharp, pointed teeth suitable for biting and chewing.

Liopleurodon showing its massive jaws, lurking around to catch prey
Liopleurodon showing its massive jaws, lurking around to catch prey | CoreyFord via iStock

Liopleurodon likely possessed a powerful sense of smell which helped them pick up the scent of prey from a distance.

Beyond that, their nose had two separate chambers that functioned like ears—they used them to pinpoint the exact location of the smell.

This is one of the best tracking devices you can find on any animal.

Habitat and Distribution

Liopleurodon were aquatic reptiles that constituted a significant part of the ecosystem about 160 million years ago.

During that time, i.e., the Jurassic period, a more substantial portion of western Europe was covered with shallow waters inhabited by plesiosaurs and pliosaurs.

Most marine reptiles in that era did not possess gills, including the Liopleurodon.

As a result, they had to come to the surface intermittently to get oxygen.

Behavior and Diet

Liopleurodon were probably solitary beings that only came together for the mating season.

Some of these reptiles likely lived in pods, while others preferred to hunt or live alone.

Still, due to their immense size, there is a good chance that they were highly territorial about their hunting space, and even males and females had confrontations that ended up in violence.

Liopleurodon was a pliosaur and apex predator of the Jurassic seas
Liopleurodon was a pliosaur and apex predator of the Jurassic seas | Daniel Eskridge via iStock

Based on findings, researchers deduced that these reptiles did not lay eggs but gave birth to their young ones live.

Also, like juvenile sharks, young Liopleurodon stayed in shallow waters with their mother until they were old enough to care for themselves.

Since they did not have gills like some whales today, they go to the surface to take a huge gulp of air which can last them for over an hour in the depths of water.

Liopleurodon was more aquatic than other plesiosaurs because of their size.

As the apex predators that they were, Liopleurodon had a wide variety of prey, ranging from ichthyosaurs to marine crocodiles, sharks, and other pliosaurs.

They even hunted Leedsichthys, which is among the largest fish that ever existed.

Liopleurodon on the hunt | MR1805 via iStock

Overall, Liopleurodon ate almost anything they encountered underwater.

Inanimate objects were not left out; they likely always tried to bite every big thing they discovered.

They would also rub their bodies on smaller objects to check if they were edible.

Liopleurodon also sometimes scavenged carcasses.

Their reputation likely made other predators stay away from them, and it would be rare to find other animals attacking the Liopleurodon except if it was severely injured.

Life Cycle

Liopleurodon is on an active predatory hunt
Liopleurodon is on an active predatory hunt | MR1805 via iStock

While some reptiles during the Jurassic period laid eggs, Liopleurodon was one of the few species that gave birth to their young ones alive.

This means the offspring was fully developed in the mother’s body before birth.

According to sources, the Liopleurodon gave birth to one offspring at a time, and they were likely the size of a baby whale.

After birth, baby Liopleurodon likely stayed with their mothers until they were mature enough to care for themselves.

The females probably also had to protect their offspring from the males who could devour them.

This brawl is one of the reasons scientists believe that most youngsters did not make it to adulthood.

Although it is hard to determine the lifespan of this creature, Liopleurodon likely lived quite long, like several reptiles we see today.

Speculatively, these marine reptiles had a slow metabolism, so they could have lived for as long as 80 to 300 years.

Evolution and History

 Liopleurodon on white background
Liopleurodon on white background | MR1805 via iStock

According to research, Liopleurodon is a member of the clade Thalassophonea of the family Pliosauridae and order Pliosauria.

Historically, the first plesiosaurs existed about 203 million years ago, during the Late Triassic period, and became prominent during the Jurassic Era.

It has been gathered that plesiosaurs most likely evolved from archosaurians and turtles that returned to the sea.

They adjusted to the marine lifestyle in the water by developing stiff vertebrae and flippers to aid movement.

With the advent of the Jurassic period, these plesiosaurs separated into short-necked and long-necked varieties until the Liopleurodon emerged.

This species was finally recognized as the biggest plesiosaurs of that age.

Behold the King of the Ancient Oceans
Behold the King of the Ancient Oceans | MR1805 via iStock

Liopleurodon was the king of the ocean for eons, but they eventually had to succumb to evolution.

Records show that a new group of marine predators emerged after a while.

They were called mosasaurs, signifying the end of Liopleurodon’s rule.

Mosasaurs were much bigger and had more powerful jaws than their predecessors, which gave the Liopleurodon real competition.

Ultimately, these carnivorous reptiles started to decline until they finally disappeared about 150 million years ago, around the beginning of the Cretaceous period.

Interactions with Other Species

Other prehistoric creatures roamed the earth during the peak years of the Liopleurodon.

Besides plesiosaurs which this reptile belonged to, there were other marine reptiles and even terrestrial animals.

Liopleurodon was a giant marine reptile that hunted other ancient marine dinosaurs in Jurassic Seas
Liopleurodon was a giant marine reptile that hunted other ancient marine dinosaurs in Jurassic Seas | CoreyFord via iStock

It is easy to guess that these species competed with Liopleurodon for food, although they were also likely prey to this creature because of its huge size and position on the food chain.

While we cannot explain accurately how these other species interacted with the Liopleurodon, we can infer that each animal type had its hunting mode, life cycle, characteristics, and behavior that made them thrive during that period.

Also, most of these marine reptiles had similar diets, which consisted of cephalopods and other sea creatures. Some were also known to be scavengers when the situation called for it.

However, many of these marine predators were hunted by the Liopleurodon, and the constant preying of the short-necked animal probably forced some prey to develop survival features and other defenses that might protect them from the apex predator.

Cultural Significance

The 19th century was a period of breakthrough in paleontology.

Although the initial fossil discoveries were centered around dinosaurs, other creatures were soon discovered, all of which gave researchers an insight into the prehistoric era.

Over the years, several findings established the existence of the Liopleurodon during the Jurassic period, but all these were still uncommon knowledge for a while.

The Liopleurodon became popular until it was finally featured in the Dinosaurs! Magazine in 1994.

Computer-generated 3D illustration with the marine reptile Liopleurodon attacking a fish
Computer-generated 3D illustration with the marine reptile Liopleurodon attacking a fish | MR1805 via iStock

However, the size of this reptile was exaggerated, with the magazine claiming that it could reach 39 feet.

In addition, the animal was portrayed as mostly toothless, only possessing a crescent of curved fangs which extended from the front of the upper and lower jaws.

Furthermore, in 1999, more people learned about this extinct animal when it was featured in the BBC series Walking With Dinosaurs.

There was also a misrepresentation of its appearance.

While paleontologists had concluded that the Liopleurodon had a maximum length of 25 feet, the series portrayed the animal as long as 80 feet.

This size was based on an excavation in Mexico that uncovered one fragmentary specimen classified as Liopleurodon and believed to represent an enormous individual.

 Liopleurodon enjoying the deep waters
Liopleurodon enjoying the deep waters | MR1805 via iStock

There was no substantial evidence to support this claim, but the series’ producers used this outrageous size anyway.

Furthermore, they got the head of the animal wrong, as well as its body proportions.

Since then, some corrections have been made to the Liopleurodon’s actual shape; you can find a reconstructed skeleton at the Museum of Paleontology in Tubingen, Germany.

Although it’s challenging to get the accurate appearance of the animal with so little evidence of its existence, paleontologists have drawn inspiration from general pliosaur anatomy.

Over the years, people have tried to draw or design the Liopleurodon differently, some as a two-dimensional image, others as three-dimensional toys and sculptures.


The Liopleurodon genus of the Pliosauridae family were marine reptiles that dominated the marine ecosystem during the Jurassic period almost 160 million years ago.

Their first fossils were recovered in the 19th century, and these items have proved pivotal in knowing more about this apex predator.

The fossils were smooth teeth, which earned the Liopleurodon its name, “smooth-sided tooth.”

Likely evolving from archosaurians and turtles, these reptiles developed aquatic features that made them thrive in the ocean.

Liopleurodon mainly stayed in shallow waters because it tended to go to the surface for air.

These apex predators were top hunters that constantly preyed on lesser animals in the open seas.

They remained at the top of the food chain until the Cretaceous period, which ushered in a more powerful species that likely led to their decline and ultimate disappearance.

The study of Liopleurodon is a means to understand the marine ecosystem of the Jurassic period precisely and the Mesozoic Era as a whole.


Was Liopleurodon Bigger than Mosasaurus?

Mosasaurus was much bigger than Liopleurodon in weight and length.

Also, the former were more powerful swimmers than the latter, although Liopleurodon likely had a more advanced sense of smell that the mosasaurs lacked.

What Were the Predators of Liopleurodon?

Due to their massive size and hunting skills, it is hard to believe that Liopleurodon had any natural enemies that could hunt them for food except for other marine reptiles in their clade.

Smaller plesiosaurs were constant prey for larger ones.

Was Liopleurodon the Largest Pliosaur?

Pliosaurs were giant reptiles that likely had an average length of 20 feet.

Although the Liopleurodon was a giant animal, it was not as big as the Australian giant Kronosaurus, which had a maximum length of 36 feet.


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