| Diet | Herbivore |
| Height | 2.5m |
| Length | 8m |
| Weight | 3 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Ornithopod |
| Location | Spain |
Arenysaurus was a remarkable ornithopod dinosaur that lived during the very end of the Cretaceous period, making it one of the last non-avian dinosaurs before the great extinction event that ended the age of dinosaurs. This impressive herbivore roamed the ancient landscapes of what is now Spain around 72 million years ago, when the region was a subtropical paradise quite different from today's Pyrenees Mountains.
As a member of the lambeosaurine group, Arenysaurus possessed one of the most distinctive features of its kind: a hollow, decorative crest on its head. This ornate structure likely served multiple purposes, including producing sounds for communication with other members of its species and possibly for display during courtship or territorial disputes. The dinosaur measured approximately 8 metres in length and stood about 2.5 metres tall at the hip, making it a substantial presence in its Late Cretaceous ecosystem.
Arenysaurus was perfectly adapted for a plant-eating lifestyle, with rows of grinding teeth that could efficiently process tough vegetation such as ferns, conifers, and flowering plants. Like other ornithopods, it could move both on two legs when travelling quickly and on all fours when feeding on low-growing plants. Its discovery has provided invaluable insights into the diversity of European dinosaurs just before their extinction.
What makes Arenysaurus particularly significant to palaeontologists is that it represents one of the most complete and precisely dated dinosaur specimens from the Late Cretaceous period in Europe, offering a unique window into life during the final chapter of the dinosaur era.
Arenysaurus had a distinctive hollow cranial crest typical of lambeosaurine hadrosaurs, which would have been used for communication and display. Its skull was robust with the characteristic duck-bill shape, and it possessed hundreds of small grinding teeth arranged in dental batteries for processing plant material.
Arenysaurus likely lived in herds, using its hollow crest to produce trumpeting calls to communicate with other members of its species across long distances. As with other ornithopods, it probably spent much of its time foraging for vegetation, alternating between bipedal locomotion when moving between feeding areas and quadrupedal postures when browsing on lower plants.
| Phylum | Chordata |
| Class | Ornithischia |
| Family | Hadrosauridae |
| Genus | Arenysaurus |
Arenysaurus was first described by Pereda-Suberbiola et al. in 2009. The original fossils were discovered at Tremp Formation, Pyrenees Mountains, Spain.
