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Chacaicosaurus

Say it: cha-KAI-koh-SORE-us

Name means: “Chacaico lizard, named after the Chacaico Sur locality”1

Ate: MeatIchthyosaursMiddle JurassicNot technically a dinosaur

Chacaicosaurus was a fast-swimming marine reptile that lived in the ocean during the Jurassic Period. It had a very long snout and big eyes to spot its prey. Even though it looked like a fish, it was a reptile that breathed air and gave birth to live babies underwater.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

171 to 169 million years ago2

Middle Jurassic

Fossils found in

Chacaico Sur locality, Neuquén Province, Argentina1 2

Food

Meat2 1

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

cool stuff

Fun facts

Chacaicosaurus had a very long snout that made up 80% of its skull length.1

It had unique rounded ridges running along each side of its snout, which no other ichthyosaur has.1

Adult Chacaicosaurus may have had very small teeth or even no teeth at all.1

The only known fossil of Chacaicosaurus was found in 1990 by a team led by Zulma Gasparini.1

Chacaicosaurus lived about 170 to 168 million years ago, during the early Bajocian stage of the Jurassic.1

Its name comes from the Chacaico Sur locality and the Greek word for lizard, while the species name cayi honors the Mapuche sea god Cay.1

Chacaicosaurus shared its ocean home with another ichthyosaur called Mollesaurus and a plesiosaur named Maresaurus.1

AI-made picture of Chacaicosaurus — An AI-made picture of how Chacaicosaurus 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: Chacaicosaurus
Named by: Fernandez 19942
Group: Ichthyosaurs
Family / clade: Baracromia2
Classification: Ichthyosauria > Ichthyosauromorpha2
Age of the rocks: 171 to 169 million years (Bajocian)2
Countries: Argentina2
Fossil records: 1 in the Paleobiology Database2
Discovery: Chacaicosaurus was named by paleontologist Marta Fernández in 1994, based on a single partial skeleton found in the Los Molles Formation of Argentina.1 2
Still debated: Scientists are not sure whether Chacaicosaurus belongs in its own genus or should be classified as a species of Stenopterygius.1

Where the facts come from

Chacaicosaurus (en.wikipedia.org)
Chacaicosaurus 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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