Diandongosaurus

Say it: dee-AN-dong-oh-SORE-us

Name means: “Diandong lizard, after the Diandong region of Yunnan, China”1

Ate: MeatOther sea reptilesMiddle TriassicNot technically a dinosaur

Diandongosaurus was a small marine reptile that swam in the warm seas of China during the Triassic Period. It had a long body and sharp teeth for catching fish. It was only about as long as a ruler!1 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

244 to 243 million years ago3

Middle Triassic

Fossils found in

Luoping County, Yunnan Province, southwestern China1 3

Food

Meat2

Length

0.34 m1

based on a referred specimen

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How big was Diandongosaurus compared to YOU?

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cool stuff

Fun facts

Diandongosaurus had a snout that was not pinched, and the part of its skull in front of the eye was longer than the part behind the eye.2

Its skull had a small opening on top (the supratemporal fenestra) that was smaller than its eye socket.2

The bones that form the forehead (frontals) and the top of the skull (parietals) were fused together into single pieces.2

Its collar bone (clavicle) had a forward-pointing projection, which is unusual.2

The toe bones (ungual phalanxes) of its hind feet were extremely flattened from top to bottom, possibly helping it paddle.2

The only known complete skeleton of Diandongosaurus was found in a famous fossil site called the Guanling Formation, which preserves many Triassic sea creatures.1

AI-made picture of Diandongosaurus — An AI-made picture of how Diandongosaurus 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 Diandongosaurus was a dinosaur because it lived long ago and had a long tail.

Truth: Diandongosaurus was not a dinosaur. It was a marine reptile called an eosauropterygian, a group that includes ancestors of plesiosaurs.1

For dino experts

Scientific name: Diandongosaurus
Named by: Shang et al. 20113
Group: Other sea reptiles
Family / clade: Eosauropterygia3
Classification: Sauropterygia3
Age of the rocks: 244 to 243 million years ()3
Rock formations: Guanling3
Countries: China3
Fossil records: 1 in the Paleobiology Database3
Discovery: Diandongosaurus was named in 2011 by Chinese paleontologists Qing-Hua Shang, Xiao-Chun Wu, and Chun Li. They described it from a complete, articulated skeleton found in the Guanling Formation of Yunnan Province.1 2
Still debated: Scientists are not sure exactly how Diandongosaurus is related to other marine reptiles. Some studies suggest it might be a close cousin of both nothosaurs and pachypleurosaurs, but its exact place in the family tree is still debated.2

Where the facts come from

Diandongosaurus (en.wikipedia.org)
A new eosauropterygian from Middle Triassic of eastern Yunnan Province, southwestern China (vertpala.ac.cn)
Diandongosaurus 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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