![115-million-year-old dinosaur blood confirmed](https://cdn.slatesource.com/5/3/f/53f92ef2-f48c-4c48-9ded-d6d0e2532170.webp) # 115-million-year-old dinosaur blood confirmed - [Made in Slatesource](https://slatesource.com/@steph/115-million-year-old-dinosaur-blood-confirmed) - By [Steph](https://slatesource.com/@steph) - Created on Nov 2, 2026 > To detect intact heme-derived molecules in 115-million-year-old red blood cells is astonishing: this really is a landmark discovery. > > — popsci.com ## Soft tissue and blood finds in dinosaur fossils Discovery Year Specimen Age What was preserved Heme confirmed Aratasaurus museunacionali, Brazil 2026 Theropod leg bone 115 million years Mineralised red blood cells + collagen amino acids Yes, chemically confirmed via spectroscopy Possible RBC structures in bone 2015 Multiple species ~75 million years Cell-like structures in vascular canals No - morphology only, chemistry not established Soft tissue and blood vessels 2005 T. rex, Montana 68 million years Flexible blood vessels, possible cell remnants Partial - subsequent studies disputed contamination Heme recovery from bone 1990s T. rex 68 million years Reported heme signals Disputed - not independently replicated at the time [newatlas.com](https://newatlas.com/biology/fossilized-blood-cells-dinosaur-bone?utm_source=slatesource) Age of fossil 115 million years Previous oldest confirmed find ~80 million years Discovery site Romualdo Formation, Brazil Specimen Right hind limb of a juvenile Aratasaurus Dinosaur length ~3 metres (10 feet) Age at death ~4 years old Key molecule detected Heme B (oxygen-carrying component of haemoglobin) Mineral preserving the cells Hausmannite (manganese oxide) Published in PNAS (Proceedings of the National Academy of Sciences) [pnas.org](https://www.pnas.org/doi/10.1073/pnas.2026?utm_source=slatesource) ## How 115 million years of survival was possible The red blood cells were mineralised by hausmannite, a compound of manganese oxide, acting as a natural time capsule. It stabilised the cellular structures and protected heme and collagen amino acids from degradation. • The fossil was buried rapidly after death in a shallow, oxygen-poor, microbe-rich environment - conditions that slowed decay. • Researchers used multiple independent methods: microscopy to locate ellipsoidal cell-like structures in vascular canals, then elemental mapping (iron, carbon, nitrogen) and spectroscopy to confirm the heme signature. • The altered form of heme B was 90 times more abundant than the unaltered form - consistent with gradual chemical change over deep time rather than recent contamination. • Contamination from fungal filaments, spores, or modern microbes was ruled out by the absence of diagnostic markers. ## One leading expert is not fully convinced Prof. Mary Schweitzer (North Carolina State University), who has herself discovered remnants of blood vessels and soft tissues in dinosaur fossils, reviewed the study and raised two objections. • Morphology: the cell-like structures do not have the nuclear bulge expected in non-mammalian red blood cells, which should appear dome-like rather than concave. • Size: the structures are smaller than most non-mammalian red blood cells, so the visual match is not met. Schweitzer was more persuaded by the chemical evidence: she told reporters that conventional wisdom on the rapid breakdown of endogenous organics is routinely challenged by modern analytical techniques. She did not dismiss the heme and collagen findings. What researchers say comes next 0% Independent replication of the heme detection in the same specimen Systematic re-examination of museum specimens using modern molecular techniques Further investigation of hausmannite as a preservation agent in other fossil sites Research into whether blood-derived biomolecules can inform dinosaur metabolism and activity levels Broader implications explored for astrobiology: if heme can survive 115 million years in harsh conditions, similar biomolecules could persist elsewhere [theconversation.com](https://theconversation.com/traces-of-dinosaur-blood-found-in-world-first-discovery-286450?utm_source=slatesource) Sources: PNAS paper (Grice et al., 2 Nov 2026), Curtin University press release, Popular Science, New Atlas, The Conversation, ScienceAlert, Livescience. Skeptical commentary from Prof. Mary Schweitzer sourced via Livescience and ScienceAlert. Cover: erythrocytes under compound microscope, CC0, Kaveri.dhavan via Wikimedia Commons. [pnas.org](https://www.pnas.org/doi/10.1073/pnas.2026?utm_source=slatesource) [Popular Science: Dinosaur blood found in fossils for the first time](https://www.popsci.com/science/first-dinosaur-blood-fossil-discovery/?utm_source=slatesource) [New Atlas: Fossilised blood cells inside a dinosaur leg bone](https://newatlas.com/biology/fossilized-blood-cells-dinosaur-bone?utm_source=slatesource) [The Conversation: Traces of dinosaur blood found in world-first discovery](https://theconversation.com/traces-of-dinosaur-blood-found-in-world-first-discovery-286450?utm_source=slatesource) [ScienceAlert: Dinosaur blood cells detected in 115-million-year-old fossil](https://www.sciencealert.com/dinosaur-blood-cells-detected-in-115-million-year-old-fossil?utm_source=slatesource)