Iguanacolossus Facts
| Diet | Herbivore |
| Height | 4m |
| Length | 10m |
| Weight | 4.5 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Early Cretaceous |
| Type | Ornithopod |
| Location | North America |

| Diet | Herbivore |
| Height | 4m |
| Length | 10m |
| Weight | 4.5 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Early Cretaceous |
| Type | Ornithopod |
| Location | North America |
Iguanacolossus was a massive ornithopod dinosaur that roamed the ancient landscapes of North America during the Early Cretaceous period, approximately 139 million years ago. This impressive herbivore earned its name, meaning 'giant iguana', from its enormous size and its relationship to the famous Iguanodon. Living in what is now Utah, Iguanacolossus inhabited a warm, humid environment filled with conifers, ferns, and early flowering plants.
Standing about 4 metres tall at the hip and stretching up to 10 metres in length, Iguanacolossus was one of the largest ornithopods of its time. Weighing an estimated 4.5 tonnes, this gentle giant possessed the characteristic ornithopod features including a duck-like bill for cropping vegetation, powerful hind legs for both walking and running, and smaller front limbs that could be used for both walking and food gathering. Its body was built for processing tough plant material, with rows of grinding teeth perfectly adapted for breaking down fibrous vegetation.
Like other ornithopods, Iguanacolossus was primarily bipedal but could drop down to all fours when feeding or moving slowly. Its discovery has provided valuable insights into the evolution of large ornithopods during the Early Cretaceous, representing an important link between earlier forms like Iguanodon and later duck-billed dinosaurs. The well-preserved skeleton found in Utah has allowed scientists to better understand how these magnificent plant-eaters adapted to their changing world.
Iguanacolossus was distinguished by its massive size, being one of the largest ornithopods of the Early Cretaceous period. It possessed a broad, duck-like bill for cropping vegetation and powerful, muscular hind legs that supported its impressive 4.5-tonne frame.
Iguanacolossus likely lived in herds, moving through forests and open areas in search of suitable vegetation. As a large herbivore, it would have spent much of its day feeding, using its specialised bill to crop tough plants and its grinding teeth to process fibrous material before swallowing.
| Phylum | Chordata |
| Class | Ornithischia |
| Genus | Iguanacolossus |
Iguanacolossus was first described by Andrew T. McDonald in 2010. The original fossils were discovered at Cedar Mountain Formation, Utah, USA.