Dino card No. 1847 of 2,027

Tylosaurus

Say it: ty-LOH-sore-us

Name means: “knob lizard”1

Ate: MeatMosasaursLate CretaceousNot technically a dinosaur

Tylosaurus was a giant marine lizard that swam in the oceans during the Late Cretaceous. It was not a dinosaur, but a mosasaur, a fierce predator with a long snout and paddle-like flippers. It could grow over 13 meters long, as big as a school bus!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

94 to 66 million years ago3

Late Cretaceous

Fossils found in

North America (USA, Canada), Europe (Belgium, France, Germany, Sweden), Africa (Angola), and the Middle East (Jordan)1 3

Food

Meat1 3

Length

up to 13 m1

largest species T. rex measured over 13 meters

Weight

200 kg to 1.1 tonnes1

early species 200-500 kg, later species around 1100 kg

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How heavy was it?

as heavy as 37 big dogs

as long as 3 cars parked in a rowas long as 72 bananas end to endas heavy as 220 watermelons

How big was Tylosaurus compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

cool stuff

Fun facts

Tylosaurus had a long, bony snout that stuck out like a prow, which is why one species is named proriger, meaning 'prow-bearing'.1

Fossils show Tylosaurus fought each other, with bite marks on skulls and other bones.1

One Tylosaurus skeleton had the remains of a 2-meter-long mosasaur, a diving bird, a fish, and a shark all in its stomach at once.1

Tylosaurus had an endothermic (warm-blooded) metabolism, unlike most modern lizards and snakes.1

It gave birth to live young, not eggs, based on its close relatives.3

Tylosaurus lived from about 93.9 to 66 million years ago, during the Late Cretaceous.3

AI-made picture of Tylosaurus — An AI-made picture of how Tylosaurus might have looked, made by a computer from what scientists know. It is a guess: the real animal may have looked different, and nobody knows its true colours.

you asked

Most asked questions about Tylosaurus

?Was Tylosaurus a dinosaur?

No, Tylosaurus was not a dinosaur. It was a mosasaur, a giant marine lizard that lived in the oceans during the Late Cretaceous.1

?How big was Tylosaurus?

The largest species, Tylosaurus rex, could grow over 13 metres (43 feet) long, about the length of a school bus.1 2

?What did Tylosaurus eat?

Tylosaurus was an apex predator that ate fish, sea turtles, birds, plesiosaurs, other mosasaurs, sharks, and even giant squid and ammonites.1

?Did Tylosaurus have any predators?

No, Tylosaurus was an apex predator, meaning it had no natural predators. It was one of the largest marine carnivores of its time.1

?Could Tylosaurus swim?

Yes, Tylosaurus was a fully aquatic marine reptile. It had a streamlined body, flippers, and a tail fin for swimming, similar to modern whales.1

?When did Tylosaurus go extinct?

Tylosaurus lived from about 92 to 66 million years ago, going extinct at the end of the Cretaceous period.1

?Did Tylosaurus lay eggs?

No, Tylosaurus likely gave birth to live young, not eggs. This is based on evidence from its close relatives, which have been found with babies inside them.1

?Why did Tylosaurus have a long snout?

The long, bony snout (rostrum) of Tylosaurus may have been used as a ramming weapon or to sense prey. It also gives the animal its name, which means 'knob lizard'.1

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Myth buster

Myth: Tylosaurus was a dinosaur.

Truth: Tylosaurus was a mosasaur, a marine reptile more closely related to modern monitor lizards and snakes than to dinosaurs.1

For dino experts

Scientific name: Tylosaurus
Named by: Marsh 18723
Group: Mosasaurs
Family / clade: Mosasauridae3
Classification: Mosasauroidea3
Age of the rocks: 94 to 66 million years (Turonian / Maastrichtian)3
Rock formations: Niobrara, Pierre Shale, Tar Heel3
Countries: USA, Sweden, Canada, Angola, Belgium, Germany3
Fossil records: 67 in the Paleobiology Database3
Discovery: The first species, T. proriger, was described in 1869 by Edward Drinker Cope, and the genus Tylosaurus was named in 1872 by Othniel Charles Marsh. The type specimen was found in Kansas, USA, in the late 1860s.1
Still debated: Scientists still debate how many species of Tylosaurus existed and how they are related to each other.1

Where the facts come from

Tylosaurus (en.wikipedia.org)
Giant Mosasaur Species from Texas Named T. rex | AMNH (amnh.org)
Tylosaurus 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.

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