Dino card No. 1478 of 2,027

Prosantosaurus

Say it: pro-SAN-toe-SORE-us

Name means: “Prosanto lizard, named after the Prosanto Formation where it was found”1

Ate: MeatSea reptilesMiddle TriassicNot technically a dinosaur

Prosantosaurus was a small, lizard-like marine reptile that swam in the warm seas of the Middle Triassic, about 241 million years ago. It had a long body and tail, and probably hunted small fish and crustaceans. It was not a dinosaur, but a relative of plesiosaurs.1 3

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

Lived

241 to 239 million years ago3

Middle Triassic

Fossils found in

Ducanfurgga locality, near Davos, Canton of Grisons, eastern Switzerland1 3

Food

Meat1

Length

0.5 m1

about 50 cm long

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

as long as 3 bananas end to end

How big was Prosantosaurus compared to YOU?

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cool stuff

Fun facts

Prosantosaurus could regrow its teeth if they broke off. This was seen for the first time in a European pachypleurosaur.1

Its teeth were less pointed and broader at the base compared to other pachypleurosaurs.1

The fossils were found at about 2700 metres above sea level in the Swiss Alps, but back then this area was covered by the Tethys Ocean.1

Six nearly complete skeletons and an isolated skull were discovered, which is a lot for such an ancient marine reptile.2

Prosantosaurus lived about 241 million years ago, during the early Ladinian stage of the Middle Triassic.1 2

It is the sister taxon to a group that includes Serpianosaurus, Proneusticosaurus, and Neusticosaurus species.2

AI-made picture of Prosantosaurus — An AI-made picture of how Prosantosaurus 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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Myth buster

Myth: Some people might think Prosantosaurus was a dinosaur because it lived in the Triassic and looked like a small reptile.

Truth: Prosantosaurus was a marine reptile called a pachypleurosaur, part of the group Sauropterygia, which is not dinosaurs. Dinosaurs were land reptiles with a different hip structure.1 3

For dino experts

Scientific name: Prosantosaurus
Named by: Klein et al. 20223
Group: Sea reptiles
Family / clade: Pachypleurosauria3
Classification: Sauropterygia3
Age of the rocks: 241 to 239 million years (Ladinian)3
Rock formations: Prosanto3
Countries: Switzerland3
Fossil records: 1 in the Paleobiology Database3
Discovery: Prosantosaurus was named in 2022 by Nicole Klein and colleagues from skeletons found in the Prosanto Formation in Switzerland. The species name scheffoldi honours Beat Scheffold, a scientific illustrator who helped with the research.1 3
Still debated: Scientists are still debating how pachypleurosaurs migrated across the Tethys Ocean, and whether Prosantosaurus's tooth replacement pattern is unique among European pachypleurosaurs.2

Where the facts come from

Prosantosaurus (en.wikipedia.org)
A new pachypleurosaur from the Early Ladinian Prosanto Formation in the Eastern Alps of Switzerland (zora.uzh.ch)
Prosantosaurus 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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