Xiaosaurus

Say it: SHAO-sore-us

Name means: “dawn lizard”1

Ate: PlantsBeaked plant-eatersMiddle Jurassic to Late Jurassic

Xiaosaurus was a tiny, speedy dinosaur that lived in what is now China about 168 million years ago. It was a plant-eater that ran on its two back legs and was only about as long as a big skateboard.1 3

Lived

171 to 155 million years ago3

Middle Jurassic to Late Jurassic

Fossils found in

Sichuan Province, China1 3

Food

Plants3 1

Length

0.94 to 1 m1 2

estimated from hind limb length

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

as long as 2 house cats nose to tailas long as 6 bananas end to end

How big was Xiaosaurus compared to YOU?

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cool stuff

Fun facts

Xiaosaurus means 'dawn lizard' because it lived during the Middle Jurassic, a time when dinosaurs were just starting to become common.1

Its thigh bone was only 11 centimeters (4.3 inches) long, showing it was a very small dinosaur.1

Scientists think Xiaosaurus might be a missing link between earlier plant-eaters like Lesothosaurus and later ones like Hypsilophodon.1 2

Only two partial skeletons of Xiaosaurus have been found, and they were damaged during digging.1 2

Xiaosaurus had a special feature: its upper arm bone (humerus) was straight when seen from the front, which is rare among early ornithischians.1

The fossils were discovered near Dashanpu in Sichuan, China, in 1979 and 1980.1 2

AI-made picture of Xiaosaurus — An AI-made picture of how Xiaosaurus 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.

you asked

Most asked questions about Xiaosaurus

?How big was Xiaosaurus?

About 1 metre (3.3 ft) long, which is about as long as a big skateboard. Its thigh bone was only 11 centimetres (4.3 in) long.1

?What did Xiaosaurus eat?

It was a herbivore, meaning it ate plants. It had leaf-shaped teeth with small bumps on the edges for chewing plants.1 3

?When did Xiaosaurus live?

It lived during the Middle Jurassic, about 170 to 163 million years ago. That is why its name means 'dawn lizard', it was an early dinosaur.1

?Is Xiaosaurus a dinosaur?

Yes, it is a small herbivorous ornithischian dinosaur. It is not a pterosaur or marine reptile.1 3

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For dino experts

Scientific name: Xiaosaurus
Named by: Dong and Tang 19833
Group: Beaked plant-eaters
Family / clade: Fabrosauridae3
Classification: Ornithischia3
Age of the rocks: 171 to 155 million years (Bajocian / Oxfordian)3
Rock formations: Shaximiao3
Countries: China3
Fossil records: 1 in the Paleobiology Database3
Discovery: Chinese paleontologists Dong Zhiming and Tang Zilu named Xiaosaurus in 1983 based on two partial skeletons found near Dashanpu, Sichuan.1 3
Still debated: Scientists are not sure exactly where Xiaosaurus belongs in the dinosaur family tree because its fossils are so incomplete. Some think it might be a nomen dubium (doubtful name).1

Where the facts come from

Xiaosaurus (en.wikipedia.org)
A Short Report on the Dinosaur Fauna from Dashanpu, Zigong, Sichuan II Ornithopoda (naturalhistory.si.edu)
Xiaosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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