| Diet | Herbivore |
| Height | 3m |
| Length | 8m |
| Weight | 3 tonnes |
| Environment | Land |
| Era | Cretaceous |
| Period | Late Cretaceous |
| Type | Ornithopod |
| Location | North America |
Adelolophus was a remarkable ornithopod dinosaur that holds the distinction of being the oldest known lambeosaur from North America. Living approximately 83.6 million years ago during the Late Cretaceous period, this duck-billed dinosaur inhabited the ancient landscapes of what is now Utah, making it the only known lambeosaur species from the Wahweap Formation.
As a herbivorous ornithopod, Adelolophus would have spent its days browsing on the diverse plant life of its coastal environment. The creature lived in a wet, semi-tropical habitat that bordered ancient seas, though it experienced more arid seasons at certain times of the year. This lush environment supported a rich ecosystem of fish, turtles, and various other dinosaurs including ceratopsids and tyrannosaurids.
Phylogenetic analysis suggests that Adelolophus was closely related to Parasaurolophus rather than other lambeosaurs like Lambeosaurus, placing it within the group Parasaurolophini. Like its relatives, it would have possessed the characteristic duck-like bill used for processing tough plant material, and likely had a distinctive crest on its head, though the exact form remains uncertain.
Unfortunately, our understanding of Adelolophus is limited as the type specimen consists of only a broken maxilla (upper jaw bone). This fragmentary evidence makes it challenging to reconstruct the complete appearance and behaviour of this ancient ornithopod, highlighting the ongoing mysteries that palaeontologists work to solve.
Adelolophus is known only from a broken maxilla, making its distinguishing features largely unknown. As a lambeosaur, it would likely have possessed a hollow crest on its head and the characteristic duck-like bill typical of hadrosaurs.
Based on its classification as a lambeosaur, Adelolophus likely used its hollow crest for communication, possibly producing trumpeting sounds to communicate with other members of its species. Like other hadrosaurs, it probably lived in herds and could move on both two and four legs depending on the situation.
| Phylum | Chordata |
| Class | Ornithischia |
| Family | Hadrosauridae |
| Genus | Adelolophus |
Adelolophus was first described by Terry Gates and colleagues in 2017. The original fossils were discovered at Wahweap Formation, Utah, USA.
