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Eurycleidus

Say it: yoo-rih-KLY-dus

Name means: “broad clavicle”1

Ate: MeatPlesiosaursEarly JurassicNot technically a dinosaur

Eurycleidus was a big, swimming reptile that lived in the sea during the Early Jurassic, about 200 million years ago. It was not a dinosaur, but a plesiosaur with a long body and strong flippers. It used its sharp, needle-like teeth to catch fish.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

201 to 184 million years ago2

Early Jurassic

Fossils found in

Fossils were found in England, United Kingdom, especially in Somerset and possibly other places.1 2

Food

Meat1 2

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

cool stuff

Fun facts

Eurycleidus had large shoulder bones, which gave it a powerful forward stroke for fast swimming.1

The first fossils were bought by Thomas Hawkins in the early 1830s from a quarry in Street, Somerset, England.1

In 1837, Richard Owen mistakenly thought the fossils came from Lyme Regis, but they actually came from Somerset.1

The species was first named Plesiosaurus arcuatus in 1840, and later renamed Eurycleidus in 1922.1

Some fossils that were once thought to be Eurycleidus were later moved to other genera, like Atychodracon and Lindwurmia.1

Eurycleidus lived in the sea and was an active swimmer, living near the surface.2

AI-made picture of Eurycleidus — An AI-made picture of how Eurycleidus 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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Myth buster

Myth: Eurycleidus was a dinosaur.

Truth: Eurycleidus was a plesiosaur, a marine reptile, not a dinosaur.1

For dino experts

Scientific name: Eurycleidus
Named by: Andrews 19222
Group: Plesiosaurs
Family / clade: Rhomaleosauridae2
Classification: Plesiosauria > Sauropterygia2
Age of the rocks: 201 to 184 million years (Hettangian / Pliensbachian)2
Rock formations: Blue Lias2
Countries: United Kingdom2
Fossil records: 4 in the Paleobiology Database2
Discovery: The first fossils were collected by Thomas Hawkins in the early 1830s from a quarry in Street, Somerset, England. Richard Owen named the species Plesiosaurus arcuatus in 1840, and Charles William Andrews renamed it Eurycleidus in 1922.1
Still debated: Scientists still debate exactly which fossils belong to Eurycleidus, because some specimens were later moved to other genera.1

Where the facts come from

Eurycleidus (en.wikipedia.org)
Eurycleidus 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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