Thecodontosaurus
THEE-koh-DON-toh-SORE-us
"socket-tooth lizard"
- Lived
- 206 to 201 million years ago, Late Triassic
- Length
- about 2.5 m (8 ft)
- Found in
- United Kingdom
- Named by
- Riley and Stutchbury 1836
Size comparison
To scale
Scale in metersOutline: typical early sauropodomorph shape
Where its fossils were found
The evidence
Today
200 million years ago
Habitat
A limestone landscape in what is now England, perhaps on small islands, where bones collected in cracks and caves. Clevosaurus was a small reptile neighbor. Diphydontosaurus also lived there.
Field notes
About Thecodontosaurus
What it was like
Thecodontosaurus was a small plant eater about 2.5 meters (8 feet) long, an early member of the long-necked line that later produced the giant sauropods. It had a small head, a long neck and tail, and mostly walked on its hind legs.
Its name comes from its teeth, which sat in sockets in the jaw, and many of them had jagged edges for slicing plants.
Its world
It lived in the Late Triassic in what is now England. Many of its bones come from cracks and caves in older limestone, which filled with sediment and bones in its time, perhaps on small islands.
How it was found
Riley and Stutchbury named Thecodontosaurus in 1836, making it one of the very first dinosaurs ever named. Several species were later added to the genus, but only the first is still accepted.
Field gallery
More views of Thecodontosaurus
Scenes reconstructed from the available fossil evidence.
Lived alongside
Found in the same rock formations
A rock formation can hold fossils laid down millions of years apart, so not every animal here met Thecodontosaurus.
The evidence
The science behind Thecodontosaurus
Which parts of the picture come from its own bones, and which come from its relatives.
From its own fossils
- Many separate bones preserve parts of the skull, backbone, shoulders, hips and limbs. Bones assigned to its hand include a short, robust thumb base and a deep claw curved toward the tip.
- Its tooth crowns have coarse serrations and lack the strong backward curve of typical meat-eating teeth.
- Muscle attachment marks on its limb bones suggest an agile animal that walked on its hind legs.
Borrowed from relatives
- Gaps in the wrist, fingers and toes are restored by comparison with Eoraptor.
- Macrocollum supplies comparisons for the missing front of the skull, gaps between backbone and shoulder bones, and the tail tip.
Still unknown
- Whether adults cared for their young.
- Its color and skin covering, and the complete shape of the front of its skull.
- Which plants it preferred to eat.
Discovery timeline
- 1836Named itRiley & Stutchbury
- 2020RedescriptionBallell, Rayfield & Benton
- 2022PostureBallell, Rayfield & Benton
Key papers
The research behind what we know of Thecodontosaurus
Named it
Named Thecodontosaurus from bones and socketed teeth found in limestone cave deposits in England.
A description of various fossil remains of three distinct saurian animals discovered in the autumn of 1834, in the Magnesian Conglomerate on Durdham Down, near Bristol. Proceedings of the Geological Society of London 2: 397-399
No link available
Redescription
Described additional bones, revised its identifying features and proposed that Pantydraco may represent a young Thecodontosaurus.
Osteological redescription of the Late Triassic sauropodomorph dinosaur Thecodontosaurus antiquus based on new material from Tytherington, southwestern England. Journal of Vertebrate Paleontology 40: e1770774
Read the paper : Osteological redescription of the Late Triassic sauropodomorph dinosaur Thecodontosaurus antiquus based on new material from Tytherington, southwestern England (opens in a new tab)Posture
Reconstructed limb muscles from attachment marks on the bones, supporting an agile animal that walked on its hind legs.
Walking with early dinosaurs: appendicular myology of the Late Triassic sauropodomorph Thecodontosaurus antiquus. Royal Society Open Science 9
Read the paper : Walking with early dinosaurs: appendicular myology of the Late Triassic sauropodomorph Thecodontosaurus antiquus (opens in a new tab)
Close relatives
Other members of Sauropodomorpha
Sources: Wikidata