Name means: Extreme Reptile Crest
Species: walkeri, tubicen, cyrtocristatus
Range: Late Cretaceous (Campanian, 85-70 MYA) from Alberta (Canada), Utah, New Mexico
Size estimate: 30-35 ft length, 2.5-3.5 tons
Discovery: William Parks, 1922
Classification: dinosauria, ornithischia, ornithopoda, hadrosauridae, lambeosaurinae
The striking profile of Parasaurolophus makes it one of the more iconic dinosaurs. It is also one of the rarer hadrosaurs, except in Utah. Several excellent Parasaurolophus skeletons and other fossils from Utah have given scientists the opportunity to study a population of these animals, including how its skeleton changed as it matured. Physical change as a result of age is known as “ontogeny.” Some Parasaurolophus skulls have long, straight crests. Others have shorter, curved crests. This led scientists to name several more species of this animal than they acknowledge today. Later theories explained the difference in crests as ontogeny or as difference between the sexes. Fossils from Utah lend support to the ontogeny theory. Juveniles grew curved crests which straightened as the animal matured.
Scientists have explained Parasaurolophus’ crest with many hypotheses over the years. The crest is hollow. Tubes run from the nose into the crest. They double back into the skull, then connect to the windpipe. At one time scientists thought hadrosaurs spent much of their time in the water. Some of them believed the crest acted like a snorkel or stored air for diving. However, the crest didn’t have a hole at the far end for breathing. It also couldn’t store enough air for an elephant-sized animal to use. Experiments now support the idea that it changed the tone of the animal’s calls. Physical and computer models of the crest show that the crest deepened Parasaurolophus’ voice. They may have rumbled like elephants to communicate over long distances or to confuse attacking predators. More tests are needed to corroborate this idea.