Massospondylus

Massospondylus is one of the best-studied early sauropodomorphs, having roamed southern Africa during the Early Jurassic period. Measuring up to six metres in length and weighing around one tonne, it had a slender neck, a small skull, and a long tail. Although older reconstructions pictured it resting on all fours, modern biomechanical research shows that adults were strictly bipedal and incapable of pronating their hands. Each thumb bore an enlarged, sharp curved claw that was likely used in feeding or defence. Exceptionally preserved nesting sites in Golden Gate Highlands National Park have yielded clutches of spherical eggs and tiny embryos, revealing fascinating details about sauropodomorph reproduction and parental care, including the fact that infants hatched as quadrupeds before becoming bipedal adults.

Fossil nesting sites with eggs containing fossilised embryos demonstrate that hatchlings walked on four legs before maturing into bipeds.

Where and when

Massospondylus lived in the Early Jurassic, from 200 to 183 million years ago (Hettangian-Pliensbachian age). Its remains come from South Africa and Lesotho and Zimbabwe, in the Elliot Formation.

The numbers

Length 5 m (estimates run from 4 to 6 m). Mass about 920 kg. Hip height about 1.4 m. That is 2.9 human-lengths, or 0.45 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Massospondylus with a bus Place on the timeline