Parasaurolophus walkeri

Parasaurolophus walkeri is a lambeosaurine hadrosaurid (hollow-crested duck-billed dinosaur) from the Late Cretaceous of Alberta, Canada. Parasaurolophus is famous for its long, backswept tubular head crest, which housed looping nasal passages that may have produced resonant calls. Despite their fame, specimens of Parasaurolophus are relatively rare, suggesting they were either a minor part of their ecosystems, or potentially lived most of the year elsewhere and only passed through on occasion (thus making fewer fossils for us to find).