Artwork showing the relative scale of humans and Parasaurolophus. Meaning 'near-crested lizard', Parasaurolophus belonged to the very successful group of hervivorous dinosaurs, flourishing during the Late Cretaceous period, called hadrosaurs ('duck-billed' dinosaurs). Relatives include Edmontosaurus and Corythosaurus. The largest species, P. walkeri, is estimated to have grown to an adult length of 9.5 m (31 ft).