Scientists have made an exciting discovery in a T. rex rib from a specimen known as “Scotty” at the Royal Saskatchewan Museum. Inside this rib, they found preserved blood vessels that date back over 66 million years. This find suggests that the dinosaur was injured and its bones were still healing when it died.
Recent research shows that fossilized bones can retain microscopic details under special circumstances, which were thought to be lost through time. The rib in question shows clear signs of trauma, particularly a significant fracture with an incomplete healing callus. This indicates that the creature was undergoing a biological response to an injury.
When bones sustain damage, our bodies respond by increasing blood flow in that area—a process called angiogenesis. New blood vessels grow to aid repair. Researchers believe that this increased vascular activity led to better preservation of the vessel structures in Scotty’s rib.
The team, led by Jerit Mitchell from the University of Regina, used advanced imaging techniques without harming the fossil. Their scans revealed small, tubular structures that extend from the bone’s core into the surrounding callus. Interestingly, a nearby piece of healthy rib showed no similar structures.
Through various chemical analyses, the researchers identified these vessels as iron-rich casts, which were filled with minerals during the fossilization process. They found mainly iron(III) oxide-hydroxide, known as goethite, a finding consistent with other studies on dinosaur vascular preservation.
This discovery also sheds light on how the rib’s preservation occurred. The bone went through several burial and exposure cycles that created different chemical conditions, influencing the minerals that filled the vascular spaces. Initially, a layer of fine-grained pyrite formed in low-oxygen groundwater. Later, under changing conditions, this pyrite partially transformed into goethite, and then more pyrite formed again, revealing the complex history of the rib’s environment.
Despite the impressive findings, no original organic material was recovered from the vessels. Any carbon detected was attributed to a coating applied during the imaging process. While the shapes and positions of the structures suggest they are related to blood vessels, they now exist only as mineralized casts.
Interestingly, the study suggests that bones with injuries may be better targets for research into soft tissues. Injured bones often have more highly packed blood vessels, offering better chances for fossil preservation.
The team plans to conduct further research comparing the vascular structures in Scotty with those in other dinosaur species and their living relatives, like birds and crocodiles. This could provide valuable insights into how vascular systems evolved over millions of years.
For more details, you can check the original study in Scientific Reports.
