In 2009 when Utah high school student Kevin Terris happened upon a small fossil fragment sticking out in the ground, he had no idea it would turn out to be part of the youngest, smallest and most complete Parasaurolophus skeleton ever found.
The duck-billed Parasaurolophus, an iconic dinosaur species marked by the prominent crest running from the top of its head down its neck, lived throughout the western part of North America around 75 million years ago. Paleontologists believe the Parasaurolophus' (pronounced PAIR-uh-SORE-AH-luf-us) hollow, bony crest tube was used like a trumpet to blast out sounds as a way of communicating with others.
The find, which was made public Tuesday by the Raymond M. Alf Museum of Paleontology at The Webb Schools in Claremont, Calif., is significant because it provides previously unknown information about how the Parasaurolophus grew up.
The specimen, which has been nicknamed "Joe the Dinosaur" and given its own website, was only a year old when it died. At under 6 feet long, the baby is marked by a low-rising bump on the top of its head that would have later grown into the iconic crest. Had it grown to adulthood, the dinosaur would have been around 25 feet long.
"Our baby Parasaurolophus is barely one-quarter of adult size, but it had already started growing its crest," said Andrew Farke, the lead scientist involved with the project. "This is surprising, because related dinosaurs didn't sprout their ornamentation until they were at least half-grown. Parasaurolophus had to get an early start in order to form its unique headgear."
Paleontologists were able to establish Joe's age at the time of death by analyzing a bone sample from his leg.
"Dinosaurs have yearly growth rings in their bone tissue, like trees. But we didn't see even one ring. That means it grew to a quarter of adult size in less than a year," said Sarah Werning of Stony Brook University, a co-author of the study on Joe, which is published in the open-access journal PeerJ.
An analysis of the bone structure and the internal anatomy of the dinosaur's skull led paleontologists to believe that baby Parasaurolophuses used much higher pitched calls than adults.
"If adult Parasaurolophus had 'woofers,' the babies had 'tweeters.' The short and small crest of baby 'Joe' shows that it may have had a much higher pitch to its call than did adults," Farke said, making reference to audio speakers. "Along with the visual differences, this might have helped animals living in the same area to figure out who was the big boss."
The significance of the fossil led researchers to undertake a complete digitization of the skeleton. Furthermore, the vast majority of the digital scans are freely available to the public online. The scientists say this is the first time scans of a nearly complete dinosaur skeleton have been posted online without access restrictions.
Terris, the student who stumbled upon the skeleton, has received his share of accolades as well. Two professional paleontologists reportedly overlooked the bone fragment, walking right past it in Grand Staircase-Escalante National Monument in southern Utah. But Terris felt like it was worth investigating.
"At first I was interested in seeing what the initial piece of bone sticking out of the rock was," Terris said. "When we exposed the skull, I was ecstatic!"