Dino card No. 1565 of 2,027

Russellosaurus

Say it: RUS-ell-oh-SORE-us

Name means: “Russell's lizard, after paleontologist Dale Russell”1 2

Ate: MeatMosasaursLate CretaceousNot technically a dinosaur

Russellosaurus was an ancient marine lizard that swam in the warm seas of Texas about 92 million years ago. It was a fast hunter with a long, slender skull and lots of sharp teeth. Even though it looked a bit like a dinosaur, it was actually a mosasaur, a relative of today's monitor lizards!1 4

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 90 million years ago4

Late Cretaceous

Fossils found in

Cedar Hill, Dallas County, Texas, USA4 1

Food

Meat4 1

Length

3 m3

Weight

70 kg3

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 2.5 big dogs

as long as 3 dogs nose to tailas long as 17 bananas end to endas heavy as 14 watermelons

How big was Russellosaurus compared to YOU?

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cool stuff

Fun facts

Russellosaurus is the oldest well-preserved mosasaur skull ever found in North America, at about 92 million years old.1 2

The only known fossil is a nearly complete skull, found in 1992 by a fossil hunter named Mark Cohen at a housing construction site.1 2

This mosasaur was small and lightly built, with a narrow skull and 16 teeth on each side of its upper and lower jaws.2

The skull bones were not fully fused together, and the bone surface had lots of blood vessels, showing the animal was still growing fast when it died.1 2

Russellosaurus is the name-giver for a whole group of mosasaurs called Russellosaurina, which includes the famous Tylosaurus and Plioplatecarpus.1 2

It lived alongside another early mosasaur called Dallasaurus, which still had legs and could probably walk on land.2

AI-made picture of Russellosaurus — An AI-made picture of how Russellosaurus 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.

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For dino experts

Scientific name: Russellosaurus
Named by: Polcyn and Bell 20054
Group: Mosasaurs
Family / clade: Mosasauridae4
Classification: Mosasauroidea4
Age of the rocks: 94 to 90 million years (Turonian)4
Rock formations: Arcadia Park Shale4
Countries: USA4
Fossil records: 1 in the Paleobiology Database4
Discovery: Russellosaurus was named in 2005 by paleontologists Michael Polcyn and G.L. Bell. The skull was discovered in 1992 by Mark Cohen, a member of the Dallas Paleontological Society, at a housing construction site in Cedar Hill, Texas.1 2
Still debated: Scientists are not sure exactly how big Russellosaurus grew, because only its skull has been found and no body bones.2

Where the facts come from

Russellosaurus (en.wikipedia.org)
Russellosaurus coheni n. gen., n. sp., a 92 million-year-old mosasaur from Texas (USA), and the definition of the parafamily Russellosaurina (cambridge.org)
Russellosaurus (books.eshikshya.org)
Russellosaurus 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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