Scelidosaurus

Scelidosaurus is an early armoured dinosaur discovered along the famous Jurassic Coast of Dorset, England. Named by Richard Owen in 1859, it is among the oldest and most completely understood of all ornithischian dinosaurs. Measuring around four metres long, Scelidosaurus was predominantly quadrupedal, although it may have occasionally reared onto its hindlegs to reach vegetation. Parallel rows of small, keeled bony osteoderms covered its neck, back, and tail, offering protection from early theropods like Megalosaurus relatives. Phylogenetically, Scelidosaurus occupies a key evolutionary position as a basal thyreophoran, close to the common ancestor of both stegosaurs and ankylosaurs. Remarkably preserved specimens preserved in marine clays retain fine skin impressions showing tiny, non-overlapping scales covering the body between its armour scutes.

It is one of the earliest complete dinosaur skeletons ever found and represents the stem ancestor of all stegosaurs and ankylosaurs.

Where and when

Scelidosaurus lived in the Early Jurassic, from 199.3 to 190.8 million years ago (Sinemurian age). Its remains come from United Kingdom, in the Charmouth Mudstone Formation.

The numbers

Length 3.8 m (estimates run from 3.5 to 4 m). Mass about 240 kg. Hip height about 1.1 m. That is 2.2 human-lengths, or 0.34 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

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