Parasaurolophus Dinosaur Figure Parasaurolophus was a large herbivorous dinosaur that lived in North America during the Late Cretaceous period. Its most distinctive feature is the long, tube-like bony crest that extends backward from its head. The internal structure of this crest is a complex network of tubes, and it is thought to have served multiple functions, including acoustics (communication), visual display, and thermoregulation. Fossil discoveries are relatively few, and it is estimated that it was one of the less numerous dinosaurs among the hadrosaurids.