Researchers find 115 million year old dinosaur blood cells in Brazil

An international team of scientists identified what they claim are the oldest fossilized red blood cells ever discovered in a dinosaur remains.

The researchers published their findings in the journal Proceedings of the National Academy of Sciences, focusing on the remains of Aratasaurus, a small meat-eating dinosaur that lived in what is now northeastern Brazil 115 million years ago. The team, led by geochemist Kliti Grice from Curtin University in Perth, Australia, analyzed the fossilized leg bones of the dinosaur.

They used electron microscopes to find small, round structures located within channels where blood vessels once flowed. Chemical analysis of these structures confirmed the presence of heme, an organic compound that allows hemoglobin to carry oxygen through a body. The researchers believe that manganese oxides, specifically hausmannite, helped stabilize these cells and certain amino acids during the fossilization process. While the discovery could offer new insights into prehistoric metabolism and activity levels, some experts remain skeptical.

Paleontologist Mary Schweitzer from the University of North Carolina, who previously found soft tissue in a Tyrannosaurus rex fossil, noted that the discovered cells are concave rather than dome-shaped. However, she agreed that the presence of heme is more convincing. Grice clarified that the study does not provide dinosaur DNA, as large biomolecules like DNA do not preserve in the same way as small molecular remains.