Dino Wiki
Cartoon of Cryptoclidus
Dino card No. 0463 of 2,027

Cryptoclidus

Say it: krip-toh-KLY-dəs
Name means: “hidden collarbone”1
Ate: MeatPlesiosaursMiddle Jurassic to Early CretaceousNot technically a dinosaur

Cryptoclidus was a medium-sized plesiosaur that swam in warm seas during the Middle and Late Jurassic. It had a small head, a long neck, and four flippers. It probably ate soft animals like squid and small 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
165 to 143 million years ago2
Middle Jurassic to Early Cretaceous
Fossils found in
England, France, Cuba, and possibly Russia and Argentina12
Food
Meat1
Length
4 m1
largest individuals
Weight
737 kg to 756 kg1

When did it live?

Triassic
Jurassic
Cretaceous
252 million years ago20114566, the asteroid

How big was it?

How long was it?

Cryptoclidus about 4 m longA bicycle about 1.8 mA car about 4.5 mAn elephant, the biggest land animal today about 6.5 mA house about 10 m

How heavy was it?

as heavy as 25 big dogs
as long as 4 dogs nose to tailas long as 22 bananas end to endas heavy as 150 watermelons

How big was Cryptoclidus compared to YOU?

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

cool stuff

Fun facts

1

The name Cryptoclidus means 'hidden collarbone' because its collarbones are tiny and hidden in the shoulder area.1

2

Fossils of Cryptoclidus have been found in the Oxford Clay of Cambridgeshire, England, and in the Kimmeridge Clay of France.1

3

The type species was first called Plesiosaurus eurymerus, which means 'wide thigh bone', because scientists mistook a front flipper bone for a back leg bone.1

4

Cryptoclidus had a small, fragile skull and teeth that could not handle tough prey, so it ate only soft animals.1

5

Scientists think Cryptoclidus used its long, intermeshing teeth to strain small animals from the water or sift through mud.1

6

The size and shape of its nostrils suggest Cryptoclidus could smell chemicals in seawater, helping it find food.1

7

Complete skeletons of Cryptoclidus have been found, including some that are nearly entirely preserved, showing both adults and juveniles.1

AI-madeAI-made picture of Cryptoclidus
An AI-made picture of how Cryptoclidus 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 Cryptoclidus

?How big was Cryptoclidus?

About 4 metres long and weighed around 737 to 756 kilograms. That is about as long as a small car.1

?What did Cryptoclidus eat?

It ate small, soft animals like squid and small fish. Its fragile teeth could not handle tough prey.1

?Was Cryptoclidus a dinosaur?

No, it was a plesiosaur, which is a marine reptile that lived in the sea. It is not a dinosaur.1

?When did Cryptoclidus live?

It lived during the Middle and Late Jurassic Period, about 166 to 160 million years ago.1

?Where were Cryptoclidus fossils found?

Fossils have been found in England, France, Cuba, and Russia. Many come from the Oxford Clay in Cambridgeshire, England.12

?Could Cryptoclidus swim?

Yes, it was a good swimmer. It used its four flippers to move through warm Jurassic seas.1

Ask Rex about Cryptoclidus

Rex only answers questions about this page. 3 questions a day.

Rex is an AI and can make mistakes. He runs on servers in the EU and questions are never saved. Never type your name or other personal things.

Myth buster

Myth: Some people think Cryptoclidus was a dinosaur.

Truth: Cryptoclidus was a plesiosaur, a marine reptile that lived in the sea, not a dinosaur.1

For dino experts

Scientific name
Cryptoclidus
Named by
(Seeley 1892)2
Group
Plesiosaurs
Family / clade
Cryptoclididae2
Classification
Plesiosauria > Sauropterygia2
Age of the rocks
165 to 143 million years (Callovian / Tithonian)2
Rock formations
Oxford Clay, Jagua, Kimmeridge Clay2
Countries
United Kingdom, Cuba, Argentina, France2
Fossil records
17 in the Paleobiology Database2
Also known as
Apractocleidus (older names now counted as the same animal)2
Discovery
The first fossils were described in 1871 by John Phillips as Plesiosaurus eurymerus. Harry Govier Seeley renamed it Cryptoclidus in 1892.12
Still debated
Scientists are not sure whether Cryptoclidus caught prey by swimming fast or by ambushing it, because its skeleton was not built for speed.1

Where the facts come from

  1. Cryptoclidus (en.wikipedia.org)
  2. Cryptoclidus 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.

Rex is hungry! Dino Wiki is a dad's project for his dino-loving son, free with no ads. Grown-ups can feed Rex a snack to help keep it online.Feed Rex

More from the same group: Plesiosaurs

Also from the same time: Late Jurassic

Ask RexAI dino helperFeed Rextip jar for grown-ups