Most of the fossils studied by the scientists came from lower body parts, such as ribs and toe bones, and not the head area. This skull, held by Maidment, is a lasting reminder of what one of the dinosaurs looked like, however.
The researchers took care to determine that the preserved cells did not come from another more modern species. The discovered red blood cells were comparable to those of living birds, such as emus, which the scientists also studied for comparison.
Like the detected dino cells, "bird red blood cells are also oval and contain nuclei," Bertazzo explained, adding that "mammals are the only animals whose red blood cells do not contain nuclei, thus we can rule out contamination from a human."
He continued, "The main difference between the dinosaur cells and those of birds is that the dinosaur cells seem to be quite a bit smaller. However, this is not surprising since they have been buried for 75 million years and have likely shrunk."
He further added that blood cells size is extremely variable within different species.