A trio of young fossil hunters made an extraordinary discovery when they stumbled upon an extremely rare Tyrannosaurus rex fossil during a family hike, and researchers say it could change what we know about dinosaurs.
Brothers Liam and Jessin Fisher, ages 9 and 12, and their cousin Kaiden Madsen, 11, set out on a fossil hunting adventure in the North Dakota badlands in 2022 when they found what looked like some large bones weathering out of the ground.
The kids reached out to their father's high-school classmate, Dr. Tyler Lyson at the Denver Museum of Nature & Science, to identify what they had found.
In the summer of 2023, the junior explorers returned to the site to help Dr. Lyson's team of paleontologists excavate the fossil. To their surprise, the discovery turned out to be a fossil treasure. Not only is it the most complete T. rex the museum has ever collected, but it is a rare juvenile specimen -- earning the nickname "Teen Rex." Paleontologists used a combination of techniques, including analyzing the bone structure, growth patterns and bone histology, to estimate its age.
"We estimated the size of teenage T. rex based on the length of the specimen's tibia (shin bone)," the museum said in a statement. "The tibia from our specimen measures 82cm, compared to that of a full-grown T. rex with a 112cm long tibia suggests that our specimen likely belongs to a teenager."
The museum said the discovery is extremely significant since only a handful of juvenile T. rex skeletons have ever been found.
"Teen Rex will fill a gap in the hypothesized growth curve of T. rex and will allow scientists to examine the growth patterns, bone structure and developmental milestones of a young T. rex," the museum said. "This information will contribute to a more comprehensive understanding of T. rex biology, behavior and how these dinosaurs adapted to their environment as they transitioned from adolescence to adulthood."
The museum estimates that the young dinosaur is approximately 25 feet long, 10 feet tall and weighed 3,500 pounds. This is much smaller than a fully grown adult T. rex, which could reach lengths of up to 40 feet or more and
weigh up to 8,000 pounds.
"The fossil of Teen Rex was collected in a plaster jacket weighing about 6,000 pounds, including plaster, burlap, rock and the fossil itself," the museum said. "The fossil of Teen Rex preserves about 30% of the skeleton collected in a plaster jacket that was nine-feet long and five-feet wide. We expect to find more of the skeleton once we open the plaster jacket and start the cleaning process."
The team plans to return to the excavation site this summer to dig further back into the hill to see if more of the skeleton is preserved.