Fossilized Skull Reveals How Crested Dinosaur Got Its Fancy Headgear

Tuesday, January 26, 2021

An illustration of the head of Parasaurolophus cyrtocristatus based on newly discovered remains.

First discovered in 1922 and best known for its distinctive crest, Parasaurolophus is one of the most recognizable dinosaurs -- a staple of childhood books and a background player in the Jurassic Park movie franchise.

An exceptionally well-preserved fossilized skull found in New Mexico in 2017 -- the first to be found in 97 years -- has revealed new details about its bizarre Elvis-style pompadour. Its analysis has allowed paleontologists to definitively identify how such a structure grew on this dinosaur.

"Imagine your nose growing up your face, three feet behind your head, then turning around to attach above your eyes. Parasaurolophus breathed through eight feet of pipe before oxygen ever reached its head," said Terry Gates, a paleontologist from North Carolina State University's department of biological sciences, in a news statement.

The hollow tube on its head contained an internal network of airways and acted a bit like a trumpet.

"Over the past 100 years, ideas for the purpose of the exaggerated tube crest have ranged from snorkels to super sniffers," said David Evans, the Temerty chair in vertebrate palaeontology at the Royal Ontario Museum in Canada.

New skull of Parasaurolophus as originally exposed in the badlands of New Mexico.

"But after decades of study, we now think these crests functioned primarily as sound resonators and visual displays used to communicate within their own species."

The animal would have lived about 75 million years ago -- a time when North America was divided by a shallow sea and many duck-billed dinosaurs, horned dinosaurs and early tyrannosaurs would have roamed the land.

"The preservation of this new skull is spectacular, finally revealing in detail the bones that make up the crest of this amazing dinosaur known by nearly every dinosaur-obsessed kid," said Joe Sertich, curator of dinosaurs at the Denver Museum of Nature & Science and the leader of the team who discovered the specimen.

Sertich and his team discovered the partial skull in 2017 while exploring the badlands of northwestern New Mexico. Only a tiny portion of the skull was visible on a steep sandstone slope, and the volunteers were surprised to find the crest intact. Bone fragments found at the site indicated that much of the skeleton may have once been preserved on an ancient sand bar, but only the partial skull, part of the lower jaw, and a handful of ribs survived erosion.

The skull belonged to Parasaurolophus cyrtocristatus, previously known from a single specimen collected in the same region of New Mexico in 1923 by legendary fossil hunter Charles H. Sternberg. It has a shorter, more curved crest than other species of this dinosaur -- although this may be related to its age at death. There are three species of Parasaurolophus currently recognized, with fossils found in New Mexico and Alberta and dating between 77 million and 73.5 million years ago.

An illustration of a group of Parasaurolophus dinosaurs being confronted by a tyrannosaurid in the subtropical forests of New Mexico 75 million years ago.

"It has answered long-standing questions about how the crest is constructed and about the validity of this particular species. For me, this fossil is very exciting," said Evans, who has also worked on unraveling the mysteries of this dinosaur for almost two decades.

The research was published in the journal PeerJ.