Parasaurolophus

Parasaurolophus is a genus of hadrosaurid dinosaurs that roamed western North America during the Late Cretaceous, about 76 to 74 million years ago. The name means near crested lizard, a reference to its distinctive cranial crest. These herbivorous dinosaurs possessed broad duck-bill jaws and beaked mouths for cropping vegetation. They could move on two hind legs or on all fours, depending on feeding and locomotion needs.

The most striking feature is the long, backward-curving cranial crest, which forms a hollow tube that extends from the skull and is connected to the nasal passages. The crest likely functioned in vocalization as a resonating chamber and may have served as a display structure for species and sex recognition. The crest shape varied among species, aiding in identification.

Parasaurolophus was first described by William Parks in 1922 from fossils found in Alberta, Canada. The type species is Parasaurolophus walkeri. Additional species have been named, including Parasaurolophus tubicen and Parasaurolophus cyrtocristatus, though the exact status of some taxa remains debated. Fossils have been found in North American formations dating to the late Campanian to early Maastrichtian stages.

In life, Parasaurolophus would have browsed on vegetation along rivers and floodplains and is commonly interpreted as a social, possibly herd-living animal, as are many other hadrosaurs. Its well-preserved skulls and the iconic crest make it one of the best-known hadrosaurs from the Late Cretaceous.