Mantellisaurus

Mantellisaurus was a medium-sized herbivorous iguanodontian dinosaur from the Early Cretaceous of western Europe. For nearly a century, its fossils were classified under the classic genus Iguanodon, until detailed anatomical studies revealed that it possessed a significantly lighter build and proportionally shorter forelimbs. It measured roughly seven metres in length and weighed around three-quarters of a tonne, making it considerably smaller than its heavy-set contemporary Iguanodon bernissartensis. Equipped with a horny beak, grinding cheek teeth, and specialised thumb spikes, it grazed on tough prehistoric ferns and cycads. Although capable of walking on all fours while feeding, its short arms suggest it was more frequently bipedal than its larger relatives. Several remarkably complete skeletons have been recovered from the Isle of Wight and the famous coal mine deposits of Bernissart in Belgium.

Historically known as the gracile form of Iguanodon, it had noticeably shorter forelimbs.

Where and when

Mantellisaurus lived in the Early Cretaceous, from 126 to 121.4 million years ago (Barremian-Aptian age). Its remains come from United Kingdom and Belgium, in the Wessex Formation.

The numbers

Length 6.5 m (estimates run from 6 to 7 m). Mass about 870 kg. Hip height about 2 m. That is 3.8 human-lengths, or 0.58 of a double-decker bus. These are estimates from near-complete skeleton; fields marked estimated by the site are length, mass, hip height.

Compare Mantellisaurus with a bus Place on the timeline