Dino card No. 1797 of 2,027

Thyreosaurus

Say it: thy-ree-oh-SORE-us

Name means: “shield lizard”1

Ate: PlantsPlated dinosMiddle Jurassic

Thyreosaurus was a medium-sized stegosaur that lived in what is now Morocco during the Middle Jurassic. It had thick, shield-like plates on its back that were different from the upright plates of other stegosaurs.2 3

Lived

168 to 162 million years ago6

Middle Jurassic

Fossils found in

Boulahfa North site near Boulemane, Middle Atlas Mountains, Morocco1

Food

Plants2

Length

6 m3

estimated body length for the holotype, an adult that had not reached maximum size

Weight

3.6 tonnes4

estimate for the largest known specimen

When did it live?

Triassic

Jurassic

Cretaceous

252 million years ago20114566, the asteroid

How big was it?

How long was it?

How heavy was it?

as heavy as 2.5 cars

as long as 6 dogs nose to tailas long as 33 bananas end to endas heavy as 120 big dogsas heavy as 720 watermelons

How big was Thyreosaurus compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

cool stuff

Fun facts

Thyreosaurus had unusual dermal armour: thick, oval to rectangular plates with a rough texture on one side and a cross-hatched pattern on the other.3

Its plates were probably lying flat on its body, not sticking up like the plates of Stegosaurus.3

The name Thyreosaurus comes from the ancient Greek word for an oblong shield, because its armour looked like shields.1

Thyreosaurus lived about 168 to 161 million years ago, during the Bathonian and Callovian ages of the Middle Jurassic.2

Its fossils were found in the El Mers III Formation in Morocco, alongside other dinosaurs like the stegosaur Adratiklit and the ankylosaur Spicomellus.1

The holotype skeleton includes nine back vertebrae, ribs, a possible leg bone, and several armour plates.1

AI-made picture of Thyreosaurus — An AI-made picture of how Thyreosaurus 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 Thyreosaurus

?How big was Thyreosaurus?

About 6 metres (20 feet) long. It was an adult but not fully grown.5 3

?What did Thyreosaurus eat?

It was a herbivore, like all stegosaurs. It ate plants.1

?Did Thyreosaurus have feathers?

No. Stegosaurs like Thyreosaurus did not have feathers.5

?When did Thyreosaurus live?

It lived during the Middle Jurassic, about 168 to 161 million years ago.5 3

?Where was Thyreosaurus found?

Its fossils were found in the El Mers III Formation in the Middle Atlas Mountains of Morocco.5 1

?Is Thyreosaurus a dinosaur?

Yes, it is a stegosaurian dinosaur.5 6

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For dino experts

Scientific name: Thyreosaurus
Named by: Zafaty et al. 20246
Group: Plated dinos
Family / clade: Stegosauridae6
Classification: Ornithischia > Stegosauria > Thyreophora6
Age of the rocks: 168 to 162 million years (Bathonian / Callovian)6
Rock formations: El Mers III6
Countries: Morocco6
Fossil records: 1 in the Paleobiology Database6
Discovery: Thyreosaurus was named in 2024 by Omar Zafaty and colleagues, based on a partial skeleton found during a geological mapping mission south of Boulemane, Morocco, in 2021.1
Still debated: Scientists are still debating exactly how Thyreosaurus's flat armour plates were arranged on its body.3

Where the facts come from

A new stegosaurian dinosaur (Ornithischia: Thyreophora) with a remarkable dermal armour from the Middle Jurassic of North Africa - ScienceDirect (sciencedirect.com)
PBDB Taxon (paleobiodb.org)
A new stegosaurian dinosaur (Ornithischia: Thyreophora) with a remarkable dermal armour from the Middle Jurassic of North Africa (ri.conicet.gov.ar)
Thyreosaurus atlasicus | Dinosaur Database by DinoAnimals.com (dinoanimals.com)
Thyreosaurus (en.wikipedia.org)
Thyreosaurus in The Paleobiology Database (CC BY 4.0): age, places, rock formations, classification.

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