| Diet | Herbivore |
| Height | 2.5m |
| Length | 7m |
| Weight | 750 kg |
| Speed | 25 km/h |
| Environment | Land |
| Era | Cretaceous |
| Period | Early Cretaceous |
| Type | Ornithopod |
| Location | Europe |
Mantellisaurus was a graceful ornithopod dinosaur that roamed the forests and floodplains of Early Cretaceous Europe between 143 and 121 million years ago. Originally classified as a species of Iguanodon, this dinosaur was recognised as its own genus in 2007 when palaeontologist Gregory Paul noted its distinctly lighter build and closer relationship to the sail-backed Ouranosaurus of Africa.
Standing about 2.5 metres tall at the hip and measuring 7 metres in length, Mantellisaurus was considerably more slender than its famous relative Iguanodon. It possessed the characteristic thumb spikes of iguanodontians, though these were proportionally smaller and more delicate. The dinosaur could move comfortably on both two and four legs, switching between bipedal locomotion when moving quickly and quadrupedal stance when feeding or resting.
As a herbivore, Mantellisaurus fed on ferns, cycads, and early flowering plants that were beginning to diversify during the Early Cretaceous. Its sophisticated dental battery allowed it to process tough plant material efficiently, whilst its long, flexible neck enabled it to browse at various heights. The dinosaur's relatively light build suggests it was well-adapted for covering considerable distances in search of food.
Fossil evidence from Belgium, England, Spain, and Germany indicates that Mantellisaurus was widespread across Early Cretaceous Europe. The abundance of complete and near-complete skeletons has made this ornithopod one of the best-understood dinosaurs from this period, providing valuable insights into iguanodontian evolution and diversity.
Mantellisaurus had a notably lighter, more graceful build than Iguanodon, with proportionally smaller thumb spikes and a more slender skull. Its limb bones were less robust, and it had a longer, more flexible neck that gave it an elegant appearance compared to its bulkier relatives.
Mantellisaurus likely lived in herds, as evidenced by multiple skeletons found together at Bernissart. Its light build and long limbs suggest it was capable of swift movement when threatened, probably fleeing from predators rather than relying on defensive weapons like its thumb spikes.
Mantellisaurus rarely appears in popular media due to its recent recognition as a separate genus, though it may have been depicted as Iguanodon in earlier films and documentaries.
Mantellisaurus was first described by Gregory Paul in 2007. The original fossils were discovered at Bernissart, Belgium and Athefield, Isle of Wight, England.
