Parasaurolophus

Parasaurolophus was a genus of ornithopod dinosaur that lived during the Late Cretaceous Period. It is known for the distinctive, long, hollow, bony crest on its skull. This crest, which varied in shape among different species, is thought to have been used for species recognition and possibly for producing sound.

Like other duck-billed dinosaurs (hadrosaurs), Parasaurolophus was a herbivore with dental batteries adapted for chewing large amounts of plant material. Fossils have been found in North America. The exact function of the crests, beyond species recognition, is debated, with theories like sound production being favored over earlier ideas like snorkeling.12