I’m a physicist who studies fossils, and I recently discovered preserved blood vessels in the world’s largest T. rex

Despite the fact that much of the current research in paleontology focuses on trying to find traces of organic remains in fossils, dinosaur DNA has unfortunately never been recovered.

A lot of what we know about dinosaurs comes from preserved bones and teeth that are dug out of the ground. These hard tissues alone, however, are limited in the information they provide.

Soft tissues are extremely rare in the fossil record, but can help provide a much more life-like reconstruction of ancient life. This includes things like muscles and ligaments, pigments or even skin (like scales or feathers), which contain detailed information on how dinosaurs lived and what they looked like.

Another interesting soft tissue that can be found in bones are blood vessels. My research team and I discovered blood vessels preserved in a Tyrannosaurus rex fossil, and our findings were recently published in Scientific Reports.

As an undergraduate physics student at the University of Regina, I joined a research team using particle accelerators to study fossils. There, I first discovered blood vessels in a bone from a T. rex using advanced 3D models. It’s been nearly six years since that moment; I am now working on my PhD where I use my background in physics to advance analysis techniques in fossil research.

An extraordinary specimen

The vessels were found in a remarkable T. rex specimen nicknamed Scotty. Held in the Royal Saskatchewan Museum’s collection in Canada, Scotty is the largest T. rex ever unearthed. The fossil also remains one of the most complete specimens of T. rex.

Scotty appeared to have had a rough life 66 million years ago; many of the recovered bones appeared to have injuries, possibly due to a fight with another dinosaur, or disease. One bone in particular, a section of rib, features a large partially healed fracture.

In general, after bones experience a traumatic event like a fracture, there is a huge increase in the activity of blood vessels in the affected area as part of the healing process. We believe this is what was found in Scotty’s rib: an extensive network of mineralized vessels that we were able to examine using reconstructed 3D models.

Revolutionizing paleontology research

When analyzing fossil bones, there are two main challenges. The first is how to examine the interior of the bones without damaging the fossil. And second, the bones are very large and can be quite dense due to the fossilization process, where minerals replace and fill in original organic materials.

At first, we thought we could perform an computed topography (CT) scan of the bone, similar to what is used for medical purposes, which allows imaging of bones without damaging them. While this solves the first problem, the second problem means that a conventional medical CT machine is not nearly powerful enough to penetrate the dense bone.

For our examination, we used synchrotron light, special high-intensity x-rays. These are produced at select particle accelerator labs, and allow us to investigate microstructures such as blood vessels in the bone with ease.

Synchrotron x-rays can also be useful for chemical analysis. We found the vessels were preserved as iron-rich mineralized casts, a common form of fossilization, but in two distinct layers. This layering is due to the complicated environmental history that led to the exceptional preservation seen in Scotty’s rib.

Written in blood vessels

By analyzing blood vessels produced by an incompletely healed fracture, we can hopefully learn how T. rex healed, helping speculation on how Scotty was able to survive after sustaining injuries. This could lead to evolutionary information comparing the vessel structures seen in Scotty to other dinosaur species, as well as modern relatives to dinosaurs like birds.

The results may also help future fossil exploration by guiding scientists to target bones that show signs of injury or disease, potentially increasing the chances of discovering more vessels or other types of preserved soft tissues.

With cross-disciplinary research and novel applications of advanced technologies, there is so much potential to recreate the past lives of dinosaurs like never before.

Jerit Leo Mitchell receives funding from Mitacs Accelerate and the Sylvia Fedoruk Centre for Nuclear Innovation.