Hiking family discovers rare T. rex fossil

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A dad, his two sons and their cousin were on a hike in the Badlands of North Dakota in 2022 when they found what looked like a dinosaur leg sticking out of a rock.

Liam Fisher lies next to the dinosaur discovery. His father texted this image to<strong> </strong>Lyson, a former classmate, who set the stage for the fossil's excavation. - Courtesy Denver Museum of Nature and Science
Liam Fisher lies next to the dinosaur discovery. His father texted this image to Lyson, a former classmate, who set the stage for the fossil's excavation. - Courtesy Denver Museum of Nature and Science

Sam Fisher, his sons, Jessin and Liam, then 10 and 7, and their cousin Kaiden Madsen, who was 9, had been amateur fossil hunters for years and knew that the area — the Hell Creek Formation — was rich with them, having yielded some of the most famous Tyrannosaurus rex skeletons in the world.

They did not know, however, that they were making a significant scientific discovery.

“My dad hollered for Jessin and Kaiden to come, and they came running up,” Liam said during a news conference Tuesday in Denver. “Dad asked, ‘What is this?’ And Jessin said, ‘That’s a dinosaur!’”

They posed for a picture with the bones, and Fisher sent the image to paleontologist and Denver Museum of Nature & Science curator Dr. Tyler Lyson, who had been a high school classmate of his.

Now, the museum has unveiled what it calls “Teen Rex,” a rare juvenile T. rex skeleton, one of only a handful in existence. The public will be able to see it get extracted from the rock at an exhibition opening on June 21.

‘Wishful thinking’

When he first got the picture of the leg bone, Lyson thought he was looking at a duck-billed dinosaur.

“I didn’t know it was a T. rex, because all I had were photos, and the knee joint looked like a duckbill,” he said. “Later, I started looking at the photos a little more closely. And the way in which the bone was breaking up into sheets indicated it might be a meat-eating dinosaur.”

He then texted his paleontologist friends, checking to see if anyone thought it might be a T. rex. “They were like, ‘No, it looks like a duckbill.’ And I was like, OK, probably just wishful thinking.”

Nevertheless, Lyson set up an excavation in July 2023, bringing along the family of discoverers. “The kids were with us every step of the way, which was great,” he said. “We realized it was a T. rex on the first day. We had cameras rolling while it was happening.”

The dinosaur-discovering family returns to the site in July 2023 for the excavation, including (clockwise from upper left) Sam Fisher, Emalynn Fisher, Danielle Fisher, Liam Fisher, Kaiden Madsen and Jessin Fisher. - Courtesy Denver Museum of Nature and Science
The dinosaur-discovering family returns to the site in July 2023 for the excavation, including (clockwise from upper left) Sam Fisher, Emalynn Fisher, Danielle Fisher, Liam Fisher, Kaiden Madsen and Jessin Fisher. - Courtesy Denver Museum of Nature and Science

Lyson was hoping to find a neck bone, which would have helped to distinguish between a duckbill dinosaur or a T. rex, as they are different in the two species. Instead, he got something much better: “We uncovered a lower jaw with a bunch of teeth sticking out,” which he believes was unmistakable proof that the fossil was a T. rex.

“I was completely, like, speechless,” said Jessin Fisher about the moment he realized the fossil was in fact a T. rex.

They then proceeded to remove the overlying rock and, over the course of 11 days, they carefully unearthed the 66 million-year-old sandstone rock layer containing the fossil, which they collected in a 9-foot-long, 5-foot-wide plaster jacket weighing more than 6,000 pounds.

It was too heavy for a regular helicopter to lift, so a more advanced Black Hawk was called in. Less than a year later, the piece is about to become a live museum exhibit, during which visitors will get to watch scientists clean up the fossil and separate the individual bones — a process that could take up to a year, Lyson said.

A 40-minute documentary titled “T-REX,” will also be shown at the exhibition; it includes behind-the-scenes footage from the excavation of the fossil.

A lower jaw of the T. rex skeleton is uncovered during the 11-day excavation. The skeleton was only about 30% complete. - Courtesy Denver Museum of Nature and Science
A lower jaw of the T. rex skeleton is uncovered during the 11-day excavation. The skeleton was only about 30% complete. - Courtesy Denver Museum of Nature and Science

Juvenile T. Rex finds: a fierce debate

Based on early estimates, Lyson thinks the fossil is that of a young T. rex that died of an unknown cause when it was 13 or 15 years old. It was about 25 feet long and weighed about 3,500 pounds. An adult T. rex was on average 40 feet long and weighed at least 8,000 pounds, according to Lyson.

The skeleton is about 30% complete, but Lyson said the bones are in good condition.

“We know we have an articulated leg with the hip bones, we have a couple of tail vertebrae, and I think a decent chunk of the skull. We hope that there’s a lot more of the skeleton inside the rock, but it’s weird that we don’t have any of the ribs, we don’t have the arms, we don’t have very many of the vertebrae — it well could be that there’s more of it where this came from,” he said, adding that he’s making plans to go back to the Hell Creek Formation and excavate more.

Juvenile dinosaur fossils are rare because they’re smaller and therefore harder to find, and more prone to having been consumed after death due to their softer bones, Lyson said. Once the researchers isolate a bone, they will be able to carefully analyze it and get more information about the fossil, and perhaps confirm whether it’s a juvenile T. rex or something else.

That distinction is a hot topic in paleontology at the moment, and a paper published this year argued that some of the few juvenile T. rex skeletons found might belong to a separate species called Nanotyrannus.

An artist's reconstruction of what the Denver Museum of Nature & Science has dubbed "Teen Rex." An exhibition on the rare discovery will open June 21 at the museum. - Courtesy Denver Museum of Nature and Science
An artist's reconstruction of what the Denver Museum of Nature & Science has dubbed "Teen Rex." An exhibition on the rare discovery will open June 21 at the museum. - Courtesy Denver Museum of Nature and Science

“That’s been a fiercely fought out debate, the Nanotyrannus versus Tyrannosaurus Rex,” Lyson said. “I still think ours is a juvenile, because it is too big to be a Nanotyrannus. There’s other things that suggest that it’s a juvenile, too, in terms of skeletal maturity. Undoubtedly, this specimen will weigh in heavily on that debate. It’s going to be another data point from which people can make their arguments, and that’s important.”

Once the bone exams are complete, Lyson will work on a scientific study outlining the discovery, which he aims to publish within the next couple of years.

Nick Longrich, a paleontologist and evolutionary biologist at the University of Bath in the United Kingdom and one of the authors of the Nanotyrannus paper, said that confirming a juvenile T. rex find would be extraordinary. “Tyrannosaurus isn’t common and juvenile dinosaurs are incredibly rare, so young T. rex are the rarest of the rare,” he said.

“For that reason I’m skeptical. So far, almost all ‘juvenile T. rex’ are actually adults of its smaller cousin, Nanotyrannus. Not knowing anything else about it, I’d tend to guess that’s what they have,” Longrich added. “But if they do finally have a good skeleton of a small T. rex, that would be pretty remarkable, and great to see — it’s sort of the holy grail of Hell Creek dinosaur fossils. But a good skeleton of a young T. rex must turn up sooner or later. I’ll be interested to see the paper.”

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