:QUOTE [links:https://www.popsci.com/science/first-dinosaur-blood-fossil-discovery/, quotetype:plain, subtitle:Prof. Kliti Grice]
To detect intact heme-derived molecules in 115-million-year-old red blood cells is astonishing: this really is a landmark discovery.

:TABLE [title:Soft tissue and blood finds in dinosaur fossils, links:https://newatlas.com/biology/fossilized-blood-cells-dinosaur-bone]
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

:STATS [links:https://www.pnas.org/doi/10.1073/pnas.2026]
[icon:CLOCK] Age of fossil | 115 million years
[icon:CHART] 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)

:INFO
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.

:INFO
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.

:CHECKLIST [links:https://theconversation.com/traces-of-dinosaur-blood-found-in-world-first-discovery-286450]
What researchers say comes next
[ ] 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

:NOTE [links:https://www.pnas.org/doi/10.1073/pnas.2026]
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.

:LINK
https://www.popsci.com/science/first-dinosaur-blood-fossil-discovery/
Popular Science: Dinosaur blood found in fossils for the first time

:LINK
https://newatlas.com/biology/fossilized-blood-cells-dinosaur-bone
New Atlas: Fossilised blood cells inside a dinosaur leg bone

:LINK
https://theconversation.com/traces-of-dinosaur-blood-found-in-world-first-discovery-286450
The Conversation: Traces of dinosaur blood found in world-first discovery

:LINK
https://www.sciencealert.com/dinosaur-blood-cells-detected-in-115-million-year-old-fossil
ScienceAlert: Dinosaur blood cells detected in 115-million-year-old fossil