Yale graduate student Tyler Lyson GRD ’12 has been thrown into the limelight this week for his discovery of a rare mummified dinosaur — a hadrosaur — that he first chanced upon eight years ago.

Although the hadrosaur fossil — which is notable for its fossilized soft tissue, such as skin and muscles, in addition to bone — was excavated in summer 2006, the discovery was released Monday to the press in conjunction with a National Geographic documentary set to air this week. The media picked up on it quickly, even prematurely, Lyson said, disseminating conclusions before he has had a chance to publish them himself.

“I would rather have it go through a peer review journal before making any claims,” Lyson said. “That’s part of the process.”

In the past several days, the story has been covered by many major news outlets, including National Geographic and the Washington Post.

But in spite of his reservations about the media hype, Lyson said he remains excited about the discovery and is excited about the evolutionary answers it could provide.

The team currently has one paper in peer-review, as well as several others that Lyson said he anticipates will be submitted later this week.

“It does paint a very accurate picture of what this dinosaur looked like 65 million years ago,” he said. “But we’ve really only just started analyzing this data.”

Lyson found the specimen in a fossil-rich area close to his home in North Dakota. He first saw traces of it in 1999, at age 16, when he was on a fossil expedition with a colleague and noticed three tail spinal bones poking out of the ground, he said. Lyson added the place to his list of possible fossil excavation sites, but did not return to it until 2004, when he brought back a group of volunteers.

He and his team did not have any idea about the magnitude of what they would eventually unearth, he said.

“It was a slow realization process,” Lyson said. “As I worked around the dinosaur that was preserved in the iron carbonate rock, I saw this suspicious-looking line running through it.”

He then halted the day’s excavation, took the sample back to the lab, and cleaned it under a microscope, revealing a well-preserved impression of skin. From then on, he said, the team proceeded with extra caution, taking more rock samples along the way to ensure optimal preservation of the specimen.

In winter of 2004, when the field season ended, Lyson said he was contacted by Phillip Manning, a paleontologist at England’s University of Manchester, who expressed interest in collaborating on the project. The two worked out a deal, Lyson said, and they returned to the site in 2006 with a group of scientists from a variety of different fields, including locomotion modeling and geochemistry.

The specimen is currently undergoing CT scans at the Boeing facility in California, Lyson said. But because it is still encased in dense rock, the instruments are having difficulty penetrating to the fossil itself.

“This is the largest thing that has ever been CT scanned,” Lyson said. “So we still don’t even know if it’s possible.”

Prior to the CT scan, Lyson said several other tests had been performed, including geochemical, isotope, and mineralogical analyses.

Based on these and other preliminary qualitative observations of the dinosaur, Lyson and other scientists said they are confident that the finding is significant.

“We usually only have part of the data, with skeletons and hard anatomy,” said Jacques Gauthier, professor of Geology and Geophysics. “But when you get mummies, you get soft tissue, parts that aren’t normally fossilized. And when they are, we get a much richer and better understanding of the biology of these long-extinct creatures.”

But until they have concrete results, Lyson said he is wary of making definitive conclusions.

“[Manning] has been claiming some different things and I tend not to do that,” he said.

Lyson’s respect for this process is reflected in the content of the documentary — entitled “Dino Autopsy” — which he said was intended not to discuss the results of the excavation, but rather to observe the process of discovery. The original plan was for the film to be released after the team published their results, he said, but the widely anticipated public interest pushed the release date up.

Although the vision of the film has remained consistent with its original intent to focus on the discovery process, it has been met with negative feedback in the scientific community, as have some of the “bold claims” — as Lyson described them — made by certain scientists to the press.

But Brian Andres GRD ’08, a graduate student in the Department of Geology and Geophysics who studies pterosaurs, said he understands the media explosion.

“It’s not the greatest situation,” Andres said. “But it kind of happens in this field. We work with a lot of really interesting organisms and people want to say things about them.”

“Dino Autopsy” will air Dec. 9 on the National Geographic Channel.