Overview
- The peer-reviewed analysis, published in PeerJ, revises long-held estimates that placed T. rex maturation near 20–25 years.
- Researchers examined leg bones from 17 tyrannosaurs spanning juveniles to older adults to reconstruct growth through a composite curve.
- Use of circularly and cross-polarized light uncovered previously overlooked annual growth rings in bone cross-sections.
- Because single bones preserve only the last one to two decades of growth, the team stitched records across specimens to estimate lifetime size, reaching roughly eight tons by about 40 years.
- The study flags two famous specimens, Jane and Petey, as statistical outliers, renewing debate over whether some small-bodied fossils belong to a separate taxon such as Nanotyrannus.