Dino card No. 0423 of 2,027

Cimoliasaurus

Say it: SIM-oh-lee-uh-SORE-us

Name means: “white chalk lizard”1

Ate: MeatPlesiosaursLate Jurassic to Late CretaceousNot technically a dinosaur

Cimoliasaurus was a long-necked marine reptile that swam in the seas during the time of the dinosaurs. It was not a dinosaur, but a plesiosaur, a type of ancient sea creature. With its strong flippers, it glided through the water hunting for fish and other prey.1 3

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

Lived

155 to 66 million years ago3

Late Jurassic to Late Cretaceous

Fossils found in

New Jersey, North Carolina, and Maryland, USA1

Food

Meat3

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

cool stuff

Fun facts

The name Cimoliasaurus means 'white chalk lizard' because its fossils were found in rocks that look like the white chalk of England.1

Cimoliasaurus lived during the Late Cretaceous period, about 70 to 66 million years ago.1

The first fossils of Cimoliasaurus were vertebrae (back bones) found in New Jersey in 1851.1

Cimoliasaurus belongs to the family Elasmosauridae, which includes some of the longest-necked plesiosaurs.1

A possible Cimoliasaurus vertebra was found by a schoolboy named Colin McEwen during a field trip in Maryland in 1988.1

Some scientists once thought Cimoliasaurus was a different kind of reptile, but now they agree it is an elasmosaurid plesiosaur.1

AI-made picture of Cimoliasaurus — An AI-made picture of how Cimoliasaurus 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 Cimoliasaurus

?What did Cimoliasaurus eat?

It was an aquatic carnivore, meaning it ate meat like fish and other sea creatures.3

?How big was Cimoliasaurus?

Nobody knows for sure because only vertebrae and teeth have been found. The vertebrae range from 2.5 to 10 cm long, so it was a medium-sized plesiosaur.2

?Where was Cimoliasaurus found?

Its fossils have been found in New Jersey, North Carolina, and Maryland in the United States.1

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For dino experts

Scientific name: Cimoliasaurus
Named by: Leidy 18513
Group: Plesiosaurs
Family / clade: Elasmosauridae3
Classification: Plesiosauria > Elasmosauridae > Sauropterygia3
Age of the rocks: 155 to 66 million years (Kimmeridgian / Maastrichtian)3
Rock formations: Navesink, Severn, Eagle Ford3
Countries: USA, United Kingdom, Canada, Australia, Chile, Czechia3
Fossil records: 18 in the Paleobiology Database3
Also known as: Hunosaurus, Iserosaurus (older names now counted as the same animal)3
Discovery: Cimoliasaurus was named by the American paleontologist Joseph Leidy in 1851. He described it from a set of neck vertebrae found in greensand deposits in Burlington County, New Jersey.1
Still debated: Scientists are not sure exactly how big Cimoliasaurus was, because only a few bones have been found so far.1

Where the facts come from

Cimoliasaurus (en.wikipedia.org)
Plesiosaur, Cimoliasaurus magnus (fossilsofnj.com)
Cimoliasaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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