Family discovers rare Tyrannosaurus rex fossil during trail

A father, his two sons and their cousin were hiking in the Badlands of North Dakota in the United States in 2022 when they encountered something that looked like a leg of a dinosaur coming out of a rock.

Sam Fisher, his children, Jessin and Liam, then 10 and 7, and their cousin, Kaiden Madsen, 9, had been amateur fossil hunters for years and knew that the area—the Hell Creek Formation—was rich in fossils, as some of the most famous Tyrannosaurus rex skeletons in the world were found there. They didn’t know, however, that they were making a significant scientific discovery.

“My dad called Jessin and Kaiden to look, and they came running,” Liam said during a conversation with journalists this week in Denver. “Dad said, ‘What is this?’ And Jessin said, ‘That’s a dinosaur!’”

They posed for a photo with the bones and Fisher sent the image to paleontologist and Denver Museum of Nature & Science curator Dr. Tyler Lyson, who had been his high school classmate. The museum revealed the “Teen Rex”, a rare juvenile T. rex skeleton, one of the few in existence. The public will be able to see it being extracted from the rock in an exhibition that will open on June 21.

“Positive thinking”

When he first received the photo 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 pictures and the knee joint looked like a duck’s bill,” he said. “Later, I started looking at the photos more closely. And the way the bone was fragmenting into layers indicated that it could be a carnivorous dinosaur.”

He then sent messages to his paleontologist friends, seeing if anyone thought it could be a T. rex. “They said, ‘No, it looks like a duckbill.’ And I thought, okay, it’s probably just wishful thinking.”

Lyson organized an excavation in July 2023, taking the family of the discoverers along. “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 this was happening.”

He hoped to find a neck bone, which would help distinguish between a duck-billed dinosaur or a T. rex, as they are different in the two species. Instead, he found something much better: “We dug up a lower jaw with a bunch of teeth sticking out,” which he believes is unmistakable proof that the fossil was what he wanted.

“I was completely speechless,” Jessin Fisher said of the moment she realized the fossil was in fact a T. rex. They then removed the overlying rock and, over the course of 11 days, carefully unearthed the 66-million-year-old sandstone layer containing the fossil, collected in a 2.7 meter long by 1.5 meter wide plaster jacket, weighing more than 2,700 thousand kilos.

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 exhibit at the museum, during which visitors will be able to watch scientists clean 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 be shown at the exhibition; it includes behind-the-scenes footage of the fossil excavation.

Juvenile T. Rex Discoveries: A Hot Topic

Based on initial estimates, Lyson believes the fossil is from a young T. rex that died of an unknown cause when it was between 13 and 15 years old. It was about 7.6 meters long and weighed around 1,600 kilos. An adult T. rex was, on average, 40 feet long and weighed at least 3,600 pounds, according to Lyson. The skeleton is about 30 percent complete, but Lyson said the bones are in good condition.

“We know we have a jointed leg with hip bones, some tail vertebrae and I think a decent part of the skull. We expect there to be a lot more of the skeleton inside the rock, but it’s strange that we don’t have any of the ribs, arms and vertebrae — there may be more where that came from,” he said, adding that he is making plans to return to the Formation. Hell Creek and dig more.

Fossils of juvenile dinosaurs are rare because they are smaller and therefore harder to find and more likely to have been consumed after death due to their softer bones, Lyson said. Once researchers isolate a bone, they will be able to analyze it carefully and gain more information about the fossil, and perhaps confirm whether it is a juvenile T. rex or something else.

This 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 may belong to a separate species called Nanotyrannus.

“This has been a fiercely contested debate, Nanotyrannus versus Tyrannosaurus Rex,” Lyson said. “I still think ours is a juvenile, because it’s too big to be a Nanotyrannus. There are other things that suggest it is young in terms of skeletal maturity. Without a doubt, this specimen will have significant weight in this debate. It will be another data point for people to make their arguments and that is important.”

Once examinations of the bones are complete, Lyson will work on a scientific study detailing the discovery, which he plans to publish within the next two 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 confirming the discovery of a juvenile T. rex would be extraordinary. “Tyrannosaurus is not common and juvenile dinosaurs are incredibly rare, so juvenile T. rex are the rarest of the rare,” he said.

“For that reason, I am skeptical. So far, almost all ‘T. rex juveniles’ are actually adults of their smaller cousin, Nanotyrannus. Not knowing anything else about it, I would tend to guess that’s what they have,” Longrich added. “But if they finally have a good skeleton of a small T. rex, that would be quite remarkable and great to see — it’s kind of the Holy Grail of Hell Creek dinosaur fossils. I’m looking forward to seeing the article.”

This content was originally created in English.

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