Mosasaurus: Profile & 7 Surprising Facts About the Marine Reptile

The Mosasaurus was a feared predator that lived during the Cretaceous period. You can recognize it by its crocodile-like jaw, long tail fin, and paddles. We have some interesting facts, seven key characteristics, a profile, and pictures of this prehistoric giant.

Mosasaurus is an extinct marine reptile that lived in the Atlantic Ocean at the same time as the dinosaurs. It was at the top of the food chain and grew up to 18 meters long and weighed 14 tons. This impressive giant became especially famous through the movie "Jurassic World" (2015).

Cool Facts About Mosasaurus

In this chapter, we’ve got the story of how the Mosasaurus was discovered and where its fossils have been found. You’ll also learn what its name means and the difference between dinosaurs and marine reptiles.

On top of that, we’ll explain the different types of marine reptiles and how some mosasaurs differed from one another.

Discovery and Locations

The first bone finds to be scientifically recognized as fossils were those of the Mosasaurus. The first skull was found by miners around 1770 near Maastricht on the "Meuse" river.

When French troops marched in during the French Revolution, they found the skull and took it to Paris in 1794 as a spoil of war. They called it the "Great Animal of Maastricht."

After a thorough examination of the skull in 1808, the French naturalist Georges Cuvier concluded that it was an extinct marine lizard, different from any animal known at the time.

This was the first time anyone had suggested that animal species could go extinct, which was a new idea back then. Over time, more and more fossils were found in Europe, North and South America, Africa, West Asia, and Antarctica.

Meaning of the Name

The genus name "Mosasaurus" means "Lizard of the Meuse" and was chosen in 1822 by William Daniel Conybeare.

It’s made up of "Mosa," the Latin word for the Belgian-Dutch river "Meuse," and "Saurus," the Latin word for "lizard."

The name was chosen because the first fossils of the marine reptile were found near the river.

Difference Between Dinosaurs and Marine Reptiles

The term "saurian" refers to extinct reptiles from the Mesozoic Era. This group of animals is divided into dinosaurs, pterosaurs, and marine reptiles.

Dinosaurs lived on land and are the saurian group with the most known species. Examples include Tyrannosaurus Rex, Velociraptor, Triceratops, or Stegosaurus.

Pterosaurs conquered the skies. Examples are Pteranodon, Pterodactylus, or the giant Quetzalcoatlus. Marine reptiles were found in the oceans. We have some examples of well-known species for you in the next section.

Types of Marine Reptiles

Marine reptiles can be divided into ichthyosaurs ("fish lizards") and sauropterygians ("flippered lizards"). Ichthyosaurs were completely adapted to life in the sea. Sauropterygians mostly had paddles instead of fish-like fins.

Mosasaurs had paddles rather than fins and still came to the surface to breathe. Visually, marine reptiles can be roughly divided into fish-like, crocodile-like, turtle-like, and snake-like forms.

Ichthyosaurs, for example, were built similarly to swordfish, whereas mosasaurs had a snake-like body. Here are some well-known marine reptile species for you:

• Plesiosaurus (turtle-like)
• Coelacanth (fish-like, still alive today)
• Pliosaurus (turtle-like)
• Ichthyosaurus (fish-like)
• Liopleurodon (crocodile-like)

The Group of Mosasaurs

The mosasaurs ("Meuse lizards") lived during the Upper Cretaceous (100.5 to 66 million years ago). Their home was the world’s oceans around Europe (Netherlands, Sweden), North America, Africa, Australia, New Zealand, and Antarctica.

This group of animals belongs to the squamates, just like modern snakes or lizards. Its largest representative is the genus Mosasaurus, with a length of up to 18 meters. Even though they all look similar, their visual features have distinct differences.

Halisaurus, for example, only grew to 4.5 meters long. Plotosaurus had a shorter and bulkier body than Mosasaurus. Its skull was proportionally smaller and shorter and tapered to a sharper point.

Tylosaurus was also a large mosasaur, reaching up to 13 meters in length. Its head was more cylindrical and didn’t resemble a crocodile’s as much as that of Mosasaurus. Other examples of mosasaurs include:

• Pannoniasaurus
• Hainosaurus
• Taniwhasaurus
• Platecarpus
• Plioplatecarpus
• Liodon
• Clidastes
• Plotosaurus

7 Characteristics of the Mosasaurus

Below, we’ve compiled the most important characteristics of the Mosasaurus for you. You’ll find out when Mosasaurus lived, how big it got, and what its habitat was like.

We’ll also classify its genus and species, describe its body structure and movement, as well as its lifestyle, diet, and hunting behavior.

Classification of the Genus and Species

In the past, 50 different species were assigned to the genus Mosasaurus. So far, only five are officially recognized: M. hoffmannii, M. missouriensis, M. conodon, M. lemonnieri, and M. beaugei.

These species belong to the subfamily Mosasaurinae and the family Mosasauridae. Mosasaurs belong to the squamates, which in turn fall into the group Sauropsida, which includes all reptiles.

The Mosasaurus species had different characteristics that distinguished them from other species. Mosasaurus hoffmannii was the largest species. It grew up to 18 meters long.

When Mosasaurus Lived

Mosasaurus lived during the Late Cretaceous. This was the last period of the Mesozoic Era before the dinosaurs went extinct. The first prehistoric reptiles already existed in the Triassic and Jurassic periods.

Mosasaurus lived from 83.6 to 66 million years ago. The specific time periods are called the Campanian (83.6 to 72 million years ago) and the Maastrichtian (72 to 66 million years ago). They are the last two stages of the Cretaceous period.

How Big Mosasaurus Was

Mosasaurus could grow up to 18 meters long, making it one of the largest marine reptiles of all time. It’s also estimated to have reached a weight of up to 14 tons.

The skull length of this marine giant is thought to be about one-tenth or one-eleventh of its total length. The largest jaw found so far is 1.7 meters long.

Habitat

Mosasaurus lived in the Atlantic Ocean and adjacent waters. It was abundant in its habitat and sat at the top of the food chain. Its remains have been found in North and South America, Africa, Europe, West Asia, and Antarctica.

The climate in these regions varied greatly, from (sub)tropical to temperate to cool. This suggests that Mosasaurus was robust and adaptable. The individual species were often distributed across different regions. Mosasaurus beaugei, for example, was only found in Morocco and Brazil.

Body and Movement

Mosasaurus had a large jaw with up to 40 teeth and powerful muscles. The teeth of most Mosasaurus species were robust. M. codon and M. lemonnieri had slightly more slender teeth. In some species, the edges of the incisors were serrated.

It also didn’t have permanent teeth. Although they were very sturdy, it lost them often, and they grew back. That’s why so many of them have been found to this day.

Its bones are similar to those of modern whales, and its body structure could withstand the water pressure in deeper waters without restricting its breathing. It steered its body with its large paddles and its long tail, which also had a paddle-like fin at its tip.

Its sense of smell was not very good. However, it had good two-dimensional vision and a wide field of view. Its eyes were located on the sides of its skull.

Lifestyle and Diet

The Mosasaurus was highly adapted to a life in the water. It usually stayed near the water’s surface and came up for air. Based on the many fractures on its fossil remains, researchers believe it had a rather rough and combat-heavy lifestyle.

Its menu included fish, sharks, ammonites, seabirds, and other marine reptiles that were smaller than it. This included, for example, sea turtles or other mosasaurs.

It’s also conceivable that it ate smaller pterosaurs, but there is no evidence for this yet.

It was in competition with the mosasaurs Prognathodon and Tylosaurus, as they fed on similar creatures. Traces in fossils show that there were fights between them.

It was likely viviparous (gave live birth), like modern whales. There’s no direct evidence of this for Mosasaurus, but there is for related mosasaurs.

Hunting Behavior

Due to Mosasaurus’s poor sense of smell, researchers assume that it was not a scavenger but an active and fierce hunter. Bite marks on a fossilized sea turtle, as well as broken and rehealed jaws of the Mosasaurus itself, support this.

Its body structure and sharp, large teeth allowed an adult Mosasaurus to prey on almost any animal it encountered. Its attack technique was likely to lie in wait and launch an effective surprise attack that quickly overpowered smaller prey.

Profile: The Mosasaurus

In the following profile, we’ve summarized the most important information about the Mosasaurus for you again. You’ll find the classification of the species, its habitat, distinctive physical features, as well as data on its weight and size.

Afterward, we have some interesting facts about Mosasaurus in pop culture and the extinction of marine reptiles.

• Genus Name: Mosasaurus ("Lizard of the Meuse")
• Known Species: M. hoffmannii, M. missouriensis, M. conodon, M. lemonnieri, M. beaugei
• Family: Mosasaurs (Mosasauridae)
• Subfamily: Mosasaurinae
• Group: Squamates (Squamata)
• Period: Cretaceous (Late Cretaceous, 83.6–66 million years ago)
• Habitat: Atlantic Ocean (North and South America, Africa, Europe, West Asia, Antarctica)
• Diet: Piscivore and carnivore
• Physical Characteristics: Large head, long tail with a tail fin, four paddles (front larger than back)
• Length: 7–18 meters
• Weight: 14 tons

Mosasaurus in Pop Culture

Thanks to the movie "Jurassic World" (2015), the Mosasaurus has made a name for itself in pop culture. The most famous scene is the feeding, where the prehistoric giant leaps out of its huge tank to eat a great white shark.

The Mosasaurus also makes an appearance at the end of the second part, "Jurassic World: Fallen Kingdom" (2018). In the video game "Ark: Survival Evolved" (2017), you can find it in the deep ocean of the "The Island" map.

You can lure it with its favorite food, tame it, and ride it. The corresponding saddle is unlocked at level 78. Otherwise, it’s also known as a toy figure from Lego, Mattel, or Schleich.

Mosasaurus versus Megalodon

Mosasaurus and Megalodon are the most dangerous predators that ever roamed our seas. A comparison of these giants helps to better assess their size difference.

It also raises the question of which of the two was stronger. Even though the Mosasaurus and the Megalodon could never have met, people love to speculate about who would have won in a fight.

We’ve compared their most important physical features for you and will tell you below who would have likely won in an encounter.

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Who is stronger?

Megalodon is both larger and heavier than Mosasaurus. Its bite force is probably the strongest that ever existed. However, it was also more cumbersome and less agile due to its mass.

Mosasaurus’s hunting technique was the surprise attack. It could have used this to its advantage in a fight and could have easily dodged the Megalodon due to its agility.

However, its bite force would not be enough to fatally injure the Megalodon with a single bite. It would be a different story for the giant shark: if it got a proper hold of the Mosasaurus, the fight would be decided quickly in its favor.

Extinction of the Marine Reptiles

Marine reptiles of the ichthyosaur group already died out 93 million years ago in the Late Cretaceous. The reasons for this are still not definitively known.

Theories suggest that larger aquatic reptiles wiped them out or that there was no longer enough food for them.

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