Parasaurolophus walkeri is one of three species of Parasaurolophus, hadrosaurid dinosaurs in the subfamily Lambeosaurinae which lived during the Cretaceous period. This species in particular lived between 76.8 and 76.9 million years ago, during the Campanian stage of the Cretaceous. Its fossils are found in North America. There are two other known fossil species: P. tubicen, which has a more complex internal crest structure, and P. cyrtocristatus, which has a small and very curved crest. The genetically-engineered Parasaurolophus lux is a modern species.