Dino card No. 1483 of 2,027

Proteosaurus

Say it: PRO-tee-oh-SORE-us

Name means: “proteus lizard, named after the proteus salamander because of its backbone shape”1

Ate: MeatIchthyosaursEarly JurassicNot technically a dinosaur

Proteosaurus was an ancient marine reptile that swam in the seas over 190 million years ago. It looked a bit like a dolphin with a long snout and lots of sharp teeth. It was one of the first complete ichthyosaur skeletons ever found!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 193 million years ago6

Early Jurassic

Fossils found in

Lyme Regis, England, and also in Belgium1 2

Food

Meat2

Length

0.895 to 0.945 m3

total length of the only known specimen (a cast); species uncertain

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 2 house cats nose to tailas long as 5 bananas end to end

How big was Proteosaurus compared to YOU?

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

cool stuff

Fun facts

Proteosaurus was named by Sir Everard Home in 1819, but the name didn't stick. Today scientists call it Ichthyosaurus platyodon instead.2 1

The first complete skeleton of Proteosaurus was discovered by Mary Anning in 1818 in Lyme Regis, England. She was only about 19 years old at the time.1

Sir Everard Home thought Proteosaurus was a link between salamanders and lizards in the 'Great Chain of Being'. That's why he gave it a name that means 'proteus lizard'.1

The original Proteosaurus skeleton was bought by the Royal College of Surgeons for £100 in 1819. Sadly, it was destroyed during a World War Two air raid in May 1941.1

Proteosaurus lived during the Early Jurassic period, between about 201 and 193 million years ago, in the Hettangian and Sinemurian ages.2

Fossils of Proteosaurus have been found in the Blue Lias formation in England and in Luxembourg, Belgium. These rocks were once the bottom of a warm, shallow sea.2

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

?How big was Proteosaurus?

The largest Ichthyosaurus species, I. somersetensis, reached about 3 to 3.3 metres (9.8 to 10.8 feet) long. Other species were smaller, like I. communis at up to 2 metres (6.6 feet).4

?What did Proteosaurus eat?

It ate fish and squid-like animals called belemnites. Stomach contents show it was a fast swimmer that chased its prey.4

?Did Proteosaurus give birth to live young?

Yes. Fossil evidence shows that Ichthyosaurus gave birth to live babies, not eggs. Some fossils even have baby skeletons inside the mother.4

?Is Proteosaurus a dinosaur?

No, it is not a dinosaur. It is a marine reptile called an ichthyosaur that lived in the sea.4

?When did Proteosaurus live?

It lived during the Early Jurassic period, between about 201 and 193 million years ago.4

?Where was Proteosaurus found?

The first complete skeleton was found in Lyme Regis, England, by Mary Anning in 1818. Fossils have also been found in Belgium, Luxembourg, and Germany.4 1

?Why is it called Proteosaurus?

Sir Everard Home named it Proteosaurus because he thought it was a link between a salamander (genus Proteus) and a lizard (sauros in Greek). The name means 'proteus lizard'.1

?What happened to the original Proteosaurus fossil?

The original skeleton was destroyed during a World War Two air raid in May 1941. But two casts of it were rediscovered in 2022 in the USA and Germany.5

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Myth buster

Myth: Proteosaurus was a dinosaur.

Truth: Proteosaurus was an ichthyosaur, a marine reptile that lived in the sea. It was not a dinosaur. Dinosaurs lived on land.1

For dino experts

Scientific name: Proteosaurus
Named by: Home 18196
Group: Ichthyosaurs
Family / clade: Proteosauridae6
Classification: Ichthyosauria > Ichthyosauromorpha6
Age of the rocks: 201 to 193 million years (Hettangian / Sinemurian)6
Rock formations: Blue Lias, Luxembourg6
Countries: United Kingdom, Belgium6
Fossil records: 6 in the Paleobiology Database6
Discovery: The first complete skeleton of Proteosaurus was found by Mary Anning in 1818 in Lyme Regis, England. Sir Everard Home named it Proteosaurus in 1819.1
Still debated: Scientists are not sure exactly how Proteosaurus gave birth. But other ichthyosaurs gave birth to live young in the water, so Proteosaurus probably did too.2

Where the facts come from

Proteosaurus | The Geological Society of London (geolsoc.org.uk)
PBDB Taxon (paleobiodb.org)
Rediscovery of two casts of the historically important ‘Proteo-saurus’, the first complete ichthyosaur skeleton | Royal Society Open Science | The Royal Society (royalsocietypublishing.org)
Ichthyosaurus (Wikipedia) (Wikipedia)
Rediscovered casts bring back historic ichthyosaur fossil destroyed in war | Natural History Museum (nhm.ac.uk)
Proteosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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