Dinosaur Blood Found in 115-Million-Year-Old Bone, Complete With Chemically Confirmed Heme

An international team led by Curtin University in Australia reports that it has found fossilized red blood cells, along with amino acids from collagen, inside a 115-million-year-old dinosaur bone, and that it has chemically proven the cells contain molecules derived from hemoglobin.

The study, published in Proceedings of the National Academy of Sciences, examined limb bones of a theropod called Aratasaurus museunacionali, recovered in northwestern Brazil. The bones held numerous red blood cells preserved inside vascular canals, the tiny channels that once carried blood.

Earlier studies have reported possible red blood cell structures in fossils. The new work is the first to show chemically that heme, the oxygen-carrying part of hemoglobin, survives inside the cells. "To detect intact heme-derived molecules in 115-million-year-old red blood cells is astonishing: This really is a landmark discovery," said lead author Kliti Grice, founding director of Curtin's WA-Organic and Isotope Geochemistry Centre.

The cells were mineralized with hausmannite, a manganese oxide mineral that the researchers say acted like a natural time capsule, stabilizing the cell structures and the biomolecules inside them across geological time. The team believes the animal was buried rapidly in a low-oxygen, microbe-rich environment shortly after it died, conditions that helped lock the material in place.

Grice said the findings "challenge longstanding assumptions that certain biomolecules such as hemoglobin cannot survive deep time." Grice is also an Australian Research Council laureate fellow and a John Curtin Distinguished Professor.

The researchers argue that the result opens a new line of work in molecular paleontology. Heme and related molecules could in principle reveal how the blood, metabolism and even activity levels of extinct animals evolved, offering what Grice called "a direct molecular window into the physiology of long-extinct animals."

Martin Van Kranendonk, head of Curtin's School of Earth and Planetary Sciences, said the research redefines how molecular structures can be preserved over long time frames or in hostile conditions, with possible implications for astrobiology and the search for ancient life elsewhere in the cosmos.

The team included researchers from the Japan Agency for Marine-Earth Science and Technology, the Brazilian National Museum, Regional University of Cariri in Brazil and Johns Hopkins University. The paper is titled "Heme signatures in mineralized red blood cells within vascular canals of a 115-million-year-old dinosaur bone" and carries the DOI 10.1073/pnas.2614248123.