Dino card No. 0166 of 2,027

Argovisaurus

Say it: ar-GOH-vih-SORE-us

Name means: “Aargau lizard”1

Ate: MeatIchthyosaursMiddle JurassicNot technically a dinosaur

Argovisaurus was a huge, dolphin-like marine reptile that swam in the warm seas of the Middle Jurassic. It was a top predator with a strong snout and sharp teeth, hunting big squid and fish. Even though it looked like a dolphin, it was actually an ichthyosaur, not a dinosaur.2

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 165 million years ago3

Middle Jurassic

Fossils found in

Oberegg north of Auenstein, Canton Aargau, Switzerland3 2

Food

Meat2

Length

4.5 to 6 m1 2

estimated total length

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 Argovisaurus compared to YOU?

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cool stuff

Fun facts

Argovisaurus lived about 170 to 165 million years ago, during the Middle Jurassic period.3

Its skull was almost 1.2 metres long, making it one of the largest ichthyosaurs of its time.2

The only known fossil was discovered by a private collector named Elmar Meier over twenty years before scientists studied it.2

Argovisaurus had a robust snout and special tooth sockets called pseudoalveoli in the front half of its jaws.2

It is one of the earliest members of the group Ophthalmosauria, which includes many later ichthyosaurs.2

Scientists used CT scans and surface scans to make a 3D reconstruction of its skull.2

The fossil was found in the Hauptrogenstein Formation, which was once a shallow, warm sea.1

AI-made picture of Argovisaurus — An AI-made picture of how Argovisaurus 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: Argovisaurus
Named by: Miedema et al. 20243
Group: Ichthyosaurs
Family / clade: Ophthalmosauridae3
Classification: Ichthyosauria > Ichthyosauromorpha3
Age of the rocks: 171 to 165 million years (Bajocian / Bathonian)3
Rock formations: Hauptrogenstein3
Countries: Switzerland3
Fossil records: 1 in the Paleobiology Database3
Discovery: Argovisaurus was named in 2024 by Miedema and colleagues. The only skeleton was found in a quarry in Switzerland by private collector Elmar Meier before 2004, and later acquired by the Paleontological Museum of the University of Zurich.3 2
Still debated: Scientists are not sure exactly how large Argovisaurus grew, because only one incomplete skeleton has been found.2

Where the facts come from

Argovisaurus (en.wikipedia.org)
A large new Middle Jurassic ichthyosaur shows the importance of body size evolution in the origin of the Ophthalmosauria | BMC Ecology and Evolution | Springer Nature Link (link.springer.com)
Argovisaurus 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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