Nanotyrannus Debate Reignited by 2025 Dueling Dinosaurs Study
A 2025 study from the North Carolina Museum of Natural Sciences on the 'Dueling Dinosaurs' specimen—a largely complete skeleton found alongside a Triceratops—has reignited the debate over whether Nanotyrannus is a distinct species or a juvenile Tyrannosaurus rex. The specimen, approximately 20 years old at death, matches the age of many adult T. rex specimens, supporting the hypothesis that Nanotyrannus is a valid species. Dr. Cary Woodruff, Curator of Vertebrate Paleontology at Frost Science, discusses the history of the debate, noting that previous evidence suggested Nanotyrannus specimens were all teenagers, while T. rex specimens were over 20. The new findings suggest that both large and small tyrannosaurs coexisted in the Hell Creek Formation 66 million years ago, analogous to wolves and coyotes in Yellowstone today.
Key facts
- Nanotyrannus lived 66 million years ago in the Hell Creek Formation.
- The 'Dueling Dinosaurs' specimen includes a nearly complete Nanotyrannus skeleton next to a Triceratops.
- The specimen was approximately 20 years old when it died.
- Previous studies found all sampled Nanotyrannus were teenagers, while T. rex were over 20.
- The study was published in 2025 by the North Carolina Museum of Natural Sciences.
- Dr. Cary Woodruff is Curator of Vertebrate Paleontology at Frost Science.
- The debate centers on whether Nanotyrannus is a distinct species or a juvenile T. rex.
- The findings suggest Nanotyrannus and Tyrannosaurus coexisted in the Hell Creek Formation.
Entities
Institutions
- Frost Science
- North Carolina Museum of Natural Sciences
- Yellowstone National Park
Locations
- Hell Creek Formation
- Yellowstone National Park