Scientists Discover Possible 115-Million-Year-Old Dinosaur Blood Cells and Heme

Researchers analyzing the hind leg bones of an Aratasaurus fossil from north-eastern Brazil have uncovered what appear to be fossilized red blood cells alongside traces of heme, the organic compound that enables hemoglobin to transport oxygen. The 115-million-year-old specimen, belonging to a small carnivorous dinosaur, was originally found in a mine in 2008 and is housed at the National Museum of Brazil.

Using electron microscopes, the research team identified small, round structures within fine channels where blood vessels once passed. Subsequent chemical testing confirmed the presence of heme, its breakdown products, and amino acid building blocks for collagen. Professor Kliti Grice of Curtin University in Western Australia, who led the study published in the Proceedings of the National Academy of Sciences, described the find as a world first for in situ fossilized red blood cells with heme-related chemistry.

Preservation Mechanism and Scientific Debate

Biological tissues typically decay rapidly, making such preservation rare and controversial. Grice suggested that hausmannite, a manganese compound that formed around the cells, may have stabilized them and the amino acids before fossilization occurred. If confirmed, the discovery could allow researchers to study ancient dinosaur metabolism, blood, and activity levels.

However, the findings have sparked debate within the scientific community. Professor Mary Schweitzer of North Carolina State University expressed skepticism regarding the cell identification, noting that the observed structures are concave rather than possessing the dome-like nuclear bulge expected in dinosaur red blood cells. Nevertheless, Schweitzer found the evidence for heme and collagen amino acids more convincing, noting that modern technology continues to challenge the belief that organic matter cannot survive past a million years. Grice cautioned that the study does not imply complex molecules like DNA survive, emphasizing that extraordinary claims require rigorous analytical proof.