Abrictosaurus

Abrictosaurus was an early, fleet-footed herbivorous dinosaur from the Early Jurassic of southern Africa, recovered from the sandstones of Lesotho and South Africa. Approximately one metre in length, it was a member of the Heterodontosauridae, noted for exhibiting different types of teeth in a single jaw. Interestingly, one known specimen of Abrictosaurus entirely lacks the prominent canine-like tusks seen in relatives, which researchers interpret either as sexual dimorphism or a sign of subadult maturity. It possessed slender hind limbs ideal for fleeing fast-moving predators and dextrous forelimbs that could grasp branches. Named 'wakeful lizard' because palaeontologist James Hopson disputed an earlier theory that these animals entered dormant hibernation periods during droughts, Abrictosaurus navigated semi-arid seasonal river plains, consuming tough foliage, seeds, and occasional roots.

Named because its discoverer refuted a hypothesis that heterodontosaurs aestivated during dry seasons.

Where and when

Abrictosaurus lived in the Early Jurassic, from 201.3 to 190.8 million years ago (Hettangian-Sinemurian age). Its remains come from Lesotho and South Africa, in the Upper Elliot Formation.

The numbers

Length 1.1 m (estimates run from 1 to 1.2 m). Mass about 3.4 kg. Hip height about 0.35 m. That is 0.6 human-lengths, or 0.1 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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