Dino card No. 0630 of 2,027

Eternauta

Say it: ee-ter-NOW-ta

Name means: “eternal sailor”1

Ate: MeatIchthyosaursLate Jurassic to Early CretaceousNot technically a dinosaur

Eternauta was a fast-swimming marine reptile that lived in the ocean during the Late Jurassic. It had a long snout and big eyes to hunt small, slippery prey like fish and squid.1 5

Fun fact: this sea reptile swam while dinosaurs walked on land. Everyone calls them dinos, but they were a different branch of reptiles.

Lived

145 to 143 million years ago5

Late Jurassic to Early Cretaceous

Fossils found in

Chacay Melehue, Neuquén Province, Patagonia, Argentina1 5

Food

Meat1 5

Length

4 to 6 m3 4

estimate based on skull length of about 1 m

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 6 dogs nose to tailas long as 33 bananas end to end

How big was Eternauta compared to YOU?

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

cool stuff

Fun facts

Eternauta is named after a character from an Argentine science fiction comic called The Eternaut, which means 'the eternal traveler'.1

Its skull shows it had a special jaw that could open and close very fast, perfect for catching quick prey.1

Eternauta had a large scleral ring in its eye, which helped it see in dark, deep water.1

This ichthyosaur lived in the same sea as other marine reptiles like Caypullisaurus, but it ate different food to avoid competition.1

The only known fossil of Eternauta includes a nearly complete skull, a rib, and a front flipper.1

Eternauta belongs to a group of ichthyosaurs called ophthalmosaurids, which had very large eyes.1 2

AI-made picture of Eternauta — An AI-made picture of how Eternauta 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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For dino experts

Scientific name: Eternauta
Named by: Campos et al. 20255
Group: Ichthyosaurs
Family / clade: Ophthalmosauridae5
Classification: Ichthyosauria > Ichthyosauromorpha5
Age of the rocks: 145 to 143 million years (Tithonian)5
Rock formations: Vaca Muerta5
Countries: Argentina5
Fossil records: 1 in the Paleobiology Database5
Discovery: The fossil was first found in the Vaca Muerta Formation in Argentina and was originally thought to be a different ichthyosaur. In 2025, scientists Lisandro Campos and colleagues named it Eternauta patagonica.1
Still debated: Scientists are still debating exactly how Eternauta is related to other ichthyosaurs, because different computer analyses give different family trees.1

Where the facts come from

Eternauta patagonica (en.wikipedia.org)
Eternauta patagonica gen. et sp. nov .: a new ophthalmosaurid ichthyosaur from the Upper Jurassic of Patagonia and its palaeoecological implications (exa.ai)
Hallan un reptil que habitó mares patagónicos hace 150 millones de años » UNLP (unlp.edu.ar)
Reportan el hallazgo de un reptil marino de ojos gigantes que hab (iipg.conicet.gov.ar)
Eternauta 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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