Dinosaurs may have left behind more than bones. An international team led by Curtin University has identified what it says are chemically confirmed traces of dinosaur blood preserved inside a 115-million-year-old fossil, a discovery that could substantially expand the known limits of molecular preservation.
The specimen belonged to Aratasaurus museunacionali, a meat-eating theropod discovered in northeastern Brazil. Researchers examining limb bones found tiny, ellipsoid structures within vascular canals. Their size and shape resemble red blood cells, but the more significant evidence came from chemistry: the structures contained iron, carbon, and nitrogen associated with heme, the oxygen-carrying component of hemoglobin. Curtin’s announcement describes the find as the first chemical confirmation of hemoglobin-derived molecules inside fossilized dinosaur red blood cells.
The work, published in Proceedings of the National Academy of Sciences under the title “Heme signatures in mineralized red blood cells within vascular canals of a 115-million-year-old dinosaur bone,” combines microscopy with chemical analysis. Scanning electron microscopy revealed structures roughly 20 micrometers across, while elemental mapping detected the ingredients expected in heme. Researchers also identified porphyrin-related compounds and a degraded heme signature, which supports an ancient origin rather than a modern contaminant. Science News detailed the analytical evidence, including the team’s efforts to distinguish the material from plant pigments such as chlorophyll. The published study is available through its DOI.
That distinction matters because fossilized soft tissue is notoriously difficult to interpret. Earlier studies have reported structures that appeared to be red blood cells, but visual resemblance alone cannot establish what the structures originally contained. Here, the location inside bone, cellular form, and molecular fingerprints reinforce one another. The researchers’ conclusions are also being treated cautiously: outside coverage notes that the discovery may represent the oldest fossilized red blood cells yet identified, while emphasizing that the material is mineralized molecular residue—not liquid blood or intact living tissue. Smithsonian Magazine’s coverage reflects that distinction.
The finding could give paleontologists new ways to investigate dinosaur physiology, including how researchers identify traces of blood-related chemistry in other fossils. It may also encourage scientists to revisit specimens previously dismissed as too old to retain meaningful biological signatures. The immediate prize is not dinosaur DNA—this discovery does not resurrect a Jurassic Park-style genome—but a more realistic glimpse into the chemistry of animals that vanished millions of years ago.
That broader implication reaches beyond dinosaur studies. If mineralized bones can preserve recognizable molecular fragments under the right conditions, similar techniques may help researchers assess ancient life in other extreme environments. The team’s next challenge will be determining how widespread this kind of preservation is, and whether comparable heme signatures can be found in fossils from other species, locations, and geological periods.
