Dino card No. 1460 of 2,027

Polycotylus

Say it: pol-ee-KOT-ih-lus

Name means: “much-cupped vertebrae”1

Ate: MeatPlesiosaursLate Jurassic to Late CretaceousNot technically a dinosaur

Polycotylus was a short-necked plesiosaur that swam in the warm seas of North America and Europe during the Cretaceous. It had a big head, strong flippers, and gave birth to live babies in the water, just like whales do today.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

152 to 72 million years ago3

Late Jurassic to Late Cretaceous

Fossils found in

Kansas, South Dakota, Alabama, and Wyoming in the USA; also France and Russia1 2

Food

Meat1 2

Length

4.7 to 5.4 m1

Weight

1 tonnes1

over 1 metric ton

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 33 big dogs

as long as 5 dogs nose to tailas long as 30 bananas end to endas heavy as 200 watermelons

How big was Polycotylus compared to YOU?

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

cool stuff

Fun facts

Polycotylus was named by famous paleontologist Edward Drinker Cope in 1869 from fossils found in Kansas.1

A fossil of Polycotylus found in Kansas contains a single large fetus inside the mother, proving that these plesiosaurs gave live birth.1

The baby Polycotylus was about 1.5 metres (4.9 feet) long, which is about 32 percent of the mother's length.1

Polycotylus had a short neck and a long head, making it look a bit like a pliosaur, but it is actually a type of plesiosaur called a polycotylid.1

Its name means 'much-cupped vertebrae' because the bones in its spine have deep cup-like hollows.1

Polycotylus lived in the Western Interior Seaway, a shallow sea that split North America in two during the Cretaceous.1

Scientists think Polycotylus gave birth to just one large baby at a time, a strategy called K-selection.1

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

?How big was Polycotylus?

Polycotylus was a medium-sized plesiosaur, measuring about 4.7 to 5.4 metres (15 to 18 feet) long and weighing over 1 metric ton (1.1 short tons).1

?Did Polycotylus have a short neck?

Yes, Polycotylus had a short neck and a long head, unlike the long-necked plesiosaurs like Elasmosaurus.1

?What did Polycotylus eat?

Polycotylus had thick teeth with striations on their surfaces, which suggests it ate fish and other marine animals, but the sources do not give a specific diet.1

?When did Polycotylus live?

Polycotylus lived toward the end of the Cretaceous period, about 84 to 66 million years ago.1

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Myth buster

Myth: Many people think all plesiosaurs had long necks like the Loch Ness Monster.

Truth: Polycotylus had a short neck and a large head, very different from long-necked plesiosaurs like Elasmosaurus.1

For dino experts

Scientific name: Polycotylus
Named by: Cope 18693
Group: Plesiosaurs
Family / clade: Polycotylidae3
Classification: Plesiosauria > Sauropterygia3
Age of the rocks: 152 to 72 million years (Kimmeridgian / Campanian)3
Rock formations: Niobrara, Frontier, Mooreville Chalk3
Countries: USA, France, Russia3
Fossil records: 10 in the Paleobiology Database3
Discovery: Edward Drinker Cope named Polycotylus in 1869 from fragmentary bones found in the Niobrara Formation of Kansas. A nearly complete skeleton was later found in Alabama in 1949 but not described until 2002.1
Still debated: Scientists are not sure exactly how many species of Polycotylus existed, and some species may be the same as others.1

Where the facts come from

Polycotylus (en.wikipedia.org)
PBDB Taxon (paleobiodb.org)
Polycotylus 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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