Lesothosaurus

Lesothosaurus was a small, graceful bird-hipped dinosaur that darted across southern Africa during the Early Jurassic. Roughly the size of a modern turkey, it represents one of the most primitive ornithischians known to science, offering valuable clues about the ancestral anatomy of the group. Its slender hindlimbs indicate that it was an exceptionally fast runner, using raw speed as its primary defence against predators. The skull of Lesothosaurus ended in a sharp, horny beak alongside grooved, leaf-like cheek teeth designed to snip off ferns and tough desert shrubs. Although some palaeontologists have proposed that it was a very early thyreophoran, most consider it a foundational branch near the very root of ornithischian evolution.

Evidence from bone histology indicates that individuals may have aestheticised or slowed their growth during dry seasons.

Where and when

Lesothosaurus lived in the Early Jurassic, from 200 to 190 million years ago (Hettangian-Sinemurian age). Its remains come from Lesotho and South Africa, in the Upper Elliot Formation.

The numbers

Length 1.5 m (estimates run from 1 to 2 m). Mass about 6.3 kg. Hip height about 0.5 m. That is 0.9 human-lengths, or 0.13 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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