Psephosaurus

Say it: SEE-fo-SORE-us

Name means: “pebble lizard”1

Ate: FishOther sea reptilesMiddle TriassicNot technically a dinosaur

Psephosaurus was a marine reptile that lived in the Middle Triassic seas, about 243 to 237 million years ago. It had a shell made of many small, pebble-like bones that protected its body. It swam in warm, shallow waters where it probably ate tiny floating creatures.1 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

247 to 237 million years ago3

Middle Triassic

Fossils found in

Germany (Baden-Württemberg), Israel, and Türkiye1 1

Food

Fish1 1

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

cool stuff

Fun facts

Psephosaurus had a carapace, or shell, made of many small, irregular bone plates called osteoderms. The big plates were separated by smaller pentagonal or hexagonal ones.2

Its name means 'pebble lizard' because its shell looked like a bunch of pebbles.1

Psephosaurus belonged to a group called placodonts, which were marine reptiles that often had crushing teeth for eating shellfish. But Psephosaurus may have been a filter feeder instead.1 1

The first fossils of Psephosaurus were found in Germany in the Hoheneck limestone, which was once an ancient estuary or bay.1

Psephosaurus lived during the Middle Triassic, about 243 to 237 million years ago, in the Longobardian age.1 1

Only one species of Psephosaurus is known: Psephosaurus suevicus. It was named by German paleontologist Eberhard Fraas in 1896.1 1

AI-made picture of Psephosaurus — An AI-made picture of how Psephosaurus 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: Psephosaurus
Named by: Fraas 18963
Group: Other sea reptiles
Family / clade: Placochelyidae3
Classification: Placodontia > Sauropterygia3
Age of the rocks: 247 to 237 million years ()3
Rock formations: Tarasci, Erfurt3
Countries: Israel, Turkey, Germany3
Fossil records: 4 in the Paleobiology Database3
Discovery: Psephosaurus was named by German scientist Eberhard Fraas in 1896. The first fossils were found at Kugelberg near Ludwigsburg-Hoheneck in Germany, and they were pieces of a poorly preserved partial shell.1 2
Still debated: Scientists are not sure exactly what Psephosaurus ate. The PBDB lists its diet as 'suspension feeder', but other placodonts usually crushed shellfish, so its feeding habits are still debated.1 1

Where the facts come from

PBDB Taxon (paleobiodb.org)
Psephosaurus suevicus E. Fraas 1896 (exa.ai)
Psephosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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