A tyrannosaur fossil from Montana, part of the 'Dueling Dinosaurs' specimens, was determined to belong to an approximately 20-year-old animal that had finished growing, supporting the case that it represents Nanotyrannus lancensis rather than a juvenile Tyrannosaurus rex.
Notes on verification
Confirmed by multiple independent, high-quality sources (CNN, National Geographic, NC State News, Sci.News) all reporting on a peer-reviewed October 2025 Nature paper by Zanno and Napoli. Primary source details (bone microstructure, growth rings, spinal fusion) are directly cited. Some scientific debate remains about broader taxonomic implications, but the core claim about age/maturity of the specimen is well-corroborated. [tier=silver indep_score=0.875 clusters=4 claim_tier=exceptional]
Sources
- The Ten Most Significant Science Stories of 2025, From Medical ... (seed:science_and_space)
- https://www.cnn.com/2025/10/30/science/dueling-dinosaurs-fossil-nanotyrannus-tyrannosaurus-rex (corroboration)
- https://www.nationalgeographic.com/science/article/nanotyrannus-t-rex-dueling-dinosaur-fossil-debate (corroboration)
- https://news.ncsu.edu/2025/10/nanotyrannus-confirmed-dueling-dinosaurs-fossil-rewrites-the-story-of-t-rex/ (corroboration)
- https://www.sci.news/paleontology/nanotyrannus-lethaeus-14323.html (corroboration)