Dino card No. 1449 of 2,027

Plesiopleurodon

Say it: PLEE-see-PLOOR-oh-don

Name means: “near side tooth”1

Ate: MeatPlesiosaursLate CretaceousNot technically a dinosaur

Plesiopleurodon was a marine reptile that swam in the warm seas of North America during the time of the dinosaurs. It had a short neck, a long snout, and a mouth full of sharp, pointy teeth. It used its four flippers to paddle through the water like a sea turtle.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 94 million years ago4

Late Cretaceous

Fossils found in

Rattlesnake Hills, Wyoming, USA2 1

Food

Meat1 4

Length

3 to 4 m1

estimate based on the 71.2 cm skull

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 4 dogs nose to tailas long as 22 bananas end to end

How big was Plesiopleurodon compared to YOU?

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

cool stuff

Fun facts

Plesiopleurodon is known from just one partial skeleton, including a complete skull that is 71.2 cm long.1

Its name means 'near side tooth' because its teeth look a lot like the teeth of the similar pliosaur Liopleurodon.1

Scientists first thought Plesiopleurodon was a pliosaur, but later studies showed it is actually a polycotylid, a type of short-necked plesiosaur.1

It lived around 100 to 94 million years ago, during the early part of the Late Cretaceous Period.2

Plesiopleurodon's front teeth were large and pointed forward, which helped it grab slippery prey.1

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

?Was Plesiopleurodon a dinosaur?

No, it was a marine reptile called a plesiosaur, not a dinosaur. It lived in the sea during the time of the dinosaurs.1 3

?How big was Plesiopleurodon?

Scientists are not sure of its total length because only one partial skeleton has been found. Its skull is 71.2 cm long.1 4

?What did Plesiopleurodon eat?

It was a carnivore that ate fish and other marine animals. Its sharp, forward-pointing teeth helped it grab slippery prey.1 3

?When did Plesiopleurodon live?

It lived during the Late Cretaceous Period, about 100 to 94 million years ago.1 4

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Myth buster

Myth: Plesiopleurodon was a dinosaur.

Truth: Plesiopleurodon was a plesiosaur, a marine reptile that lived in the sea. It was not a dinosaur, even though it lived at the same time.1

For dino experts

Scientific name: Plesiopleurodon
Named by: Carpenter 19964
Group: Plesiosaurs
Family / clade: Polycotylidae4
Classification: Plesiosauria > Sauropterygia4
Age of the rocks: 100 to 94 million years (Cenomanian)4
Rock formations: 'Hailey Shales'4
Countries: USA4
Fossil records: 1 in the Paleobiology Database4
Discovery: Plesiopleurodon was named by paleontologist Kenneth Carpenter in 1996. He based it on a skull, neck bones, and shoulder bones found in Wyoming, USA.4 1
Still debated: Scientists are still not sure whether the only known fossil of Plesiopleurodon came from the Belle Fourche Shale or the Hailey Shales Formation, because the original records disagree.1

Where the facts come from

Plesiopleurodon (en.wikipedia.org)
PBDB Taxon (paleobiodb.org)
Plesiopleurodon: Overview, Size, Habitat, & Other Facts - Dinosaur Dictionary (dinosaurdictionary.com)
Plesiopleurodon 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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