3 boys discover rare T. rex fossil, and a film crew captured its excavation

In July 2022, two young brothers, ages 7 and 10, were hiking through the North Dakota badlands with their father and 9-year-old cousin when they found a bone protruding from the ground.

Liam and Jessen Fisher and Kaiden Madsen knew the stretch of barren terrain was fossil-rich, but while discussing the find publicly for the first time Monday, they said they thought it was "chunkosaurus," their term for unidentifiable fossil fragments common to the southwest corner of the state and the surrounding Hell Creek Formation.

Sam Fisher/AP

At the time of the discovery, the brothers’ father, Sam Fisher, texted a photo of the find to his friend Tyler Lyson, the associate curator of vertebrate paleontology at the Denver Museum of Nature & Science.

Lyson said he and his colleagues first thought the bone could belong to a duckbill dinosaur but were able to organize an excavation because the find was made on federal land. He invited Sam, the boys and their sister along with paleontologists on the dig. And just hours into the excavation, it became clear they weren't unearthing a duckbill dinosaur.

"I'll always remember that first day of the dig and the moment that Jessen and I shared when we uncovered the lower jaw, with several big T. rex teeth sticking out of it," Lyson said. "It was just an unbelievable moment."

As fortune would have it, a film crew was there to document the discovery.

"It was electric," said Dave Clark with Giant Screen Films, which produces ultra-high-resolution nature films for IMAX screens and the like. "You got goosebumps, some people had tears in their eyes ... Just to uncover something so special, and be witness to it. It was an extraordinary moment."

Andy Wood/AP

A Black Hawk helicopter lifted the fossil and surrounding rock from the ground before it was driven to Denver.

Now, the Denver Museum of Nature & Science is tasked with revealing the rest of the fossil. They’ll chip away at the rock for a special exhibit at the museum debuting June 21, called "Discovering Teen Rex."

It’s not yet clear how complete the fossil is, though Lyson said they've found a lower leg, pelvis and multiple tail bones.

The documentary, called "T.REX," will premiere later this month.

This story was originally published by Landon Haaf at Scripps News Denver .