Dino card No. 1207 of 2,015

Mosasaurus

Say it: MOH-sah-SORE-us

Name means: “Meuse lizard, after the Meuse River in the Netherlands”1

Ate: MeatMosasaursLate CretaceousNot technically a dinosaur

Mosasaurus was a giant marine reptile that ruled the oceans at the end of the Age of Dinosaurs. It was not a dinosaur but a close relative of modern lizards and snakes. With its powerful jaws and long tail, it was a top predator in the sea.1

Fun fact: this sea reptile swam while dinosaurs walked on land. Everyone calls them dinos, but they were a different branch of reptiles.

Lived

100 to 62 million years ago2

Late Cretaceous

Fossils found in

Fossils have been found in many places around the world, including the Netherlands, the United States (Alabama, Colorado, New Jersey, South Dakota, Texas, and others), Canada, Morocco, Japan, New Zealand, and Antarctica.2 1

Food

Meat1

Length

10 to 17 m1

estimates vary by species; the largest species is Mosasaurus hoffmannii

Artist's life restoration of Mosasaurus — How Mosasaurus may have looked, by Nobu Tamura email:[email protected] http://spinops.blogspot.com/. CC BY-SA 4.0, via Wikimedia Commons. Scientists still argue about colours and details.

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

cool stuff

Fun facts

Mosasaurus was first discovered in 1766 in a limestone quarry near Maastricht, Netherlands, long before the word 'dinosaur' was even invented.1

The first Mosasaurus skull was seized by the French army in 1795 and is still on display in Paris today.1

Mosasaurus had a special joint in its lower jaw that allowed it to open its mouth extra wide, so it could swallow very large prey.1

Unlike most lizards, Mosasaurus gave birth to live young in the open ocean and did not need to come ashore to lay eggs.1

Some Mosasaurus species were warm-blooded, which helped them live in both cold polar waters and warm tropical seas.1

Mosasaurus teeth were curved and sharp, and they sat in sockets like ours, which helped it bite hard without hurting itself.1

Mosasaurus lived during the Late Cretaceous Period, from about 94 million to 66 million years ago, when a huge sea called the Western Interior Seaway covered parts of North America.1

Myth buster

Myth: Mosasaurus is a dinosaur.

Truth: Mosasaurus is not a dinosaur. It is a marine reptile and a member of the squamate group, which includes modern lizards and snakes.1

For dino experts

Scientific name: Mosasaurus
Named by: Parkinson 18222
Group: Mosasaurs
Family / clade: Mosasauridae2
Classification: Mosasauroidea2
Age of the rocks: 100 to 62 million years (Cenomanian to Danian)2
Rock formations: Navesink, Severn, Pierre Shale2
Countries: USA, Syria, United Kingdom, Morocco, New Zealand, Poland2
Fossil records: 130 in the Paleobiology Database2
Discovery: The first Mosasaurus fossils were found in 1766 near Maastricht, Netherlands. The animal was named Mosasaurus in 1822 by James Parkinson, after the Meuse River. The famous French naturalist Georges Cuvier later confirmed it was a giant lizard.2 1
Still debated: Scientists are still debating the exact sizes of different Mosasaurus species, because only a few complete skeletons have been found.1

Where the facts come from

What is a mosasaur? Facts about Mosasaurus and its relatives | Natural History Museum (nhm.ac.uk)
Mosasaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

Every fact on this page has a number that points to its source. If we got something wrong, sorry, we are dino fans, not a science journal. Tell us at [email protected] and we will fix it.