Fossilized blood vessels found inside rib of largest T. rex

Researchers examining a rib from Scotty, the largest Tyrannosaurus rex ever found, discovered a fossilized network of blood vessels formed as a fracture healed 66 million years ago. Neutron imaging at Oak Ridge National Laboratory produced detailed 3D scans without damaging the fossil.

• Scotty's rib preserved mineralized blood vessels never before seen in a fossil
• The vessels formed during healing, but the dinosaur died before the fracture closed
• Imaging used the MARS and VENUS instruments at ORNL in April 2026
• The approach combines neutron and X-ray imaging to detect soft tissue