Thecodontosaurus

Thecodontosaurus is famous as the fourth dinosaur ever named scientifically, described from bones quarried near Bristol, England, in 1836. Living around 205 million years ago at the end of the Triassic, this small, graceful creature was a very early sauropodomorph. Adults grew to around two metres in length, weighing scarcely more than an average dog. They inhabited a chain of limestone islands surrounded by warm tropical seas, which may have kept their body size relatively small. Walking almost exclusively on its hind legs, Thecodontosaurus possessed nimble hands equipped with a prominent thumb claw, used for grasping foliage or defence. While many original fossils were destroyed during air raids in 1940, numerous newer specimens have preserved its anatomy in great detail.

Fossils were discovered inside limestone fissures on ancient tropical islands that once dotted the Bristol Channel.

Where and when

Thecodontosaurus lived in the Late Triassic, from 208 to 201.3 million years ago (Rhaetian age). Its remains come from United Kingdom, in the Magnesian Conglomerate.

The numbers

Length 1.6 m (estimates run from 1.2 to 2 m). Mass about 17 kg. Hip height about 0.4 m. That is 0.9 human-lengths, or 0.14 of a double-decker bus. These are estimates from partial skeleton; fields marked estimated by the site are length, mass, first ma, last ma, hip height.

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