DINOSAURS • MOLECULAR PALEONTOLOGY • PRESERVATION
Aratasaurus: Blood-Cell and Heme Evidence in Dinosaur Bone
A study of 115-million-year-old bones combines mineralized microscopic structures with chemical clues to ancient biology.
ADDED NOVEMBER 2, 2026 • PNAS STUDY PUBLISHED NOVEMBER 2, 2026
What the researchers report
A team led by Kliti Grice at Curtin University studied limb bones of the Brazilian theropod Aratasaurus museunacionali. In Proceedings of the National Academy of Sciences, they report ellipsoidal microstructures confined to vascular canals and interpret them as mineralized red blood cells.
The study identified parent and chemically altered heme B in bone extracts using high-performance liquid chromatography–mass spectrometry. The surrounding rock instead showed chlorophyll and bacteriochlorophyll signatures, supporting the authors’ interpretation that the heme originated within the bone.
Why combining methods matters
Spatially resolved Raman spectroscopy detected heme-related porphyrin signals in the structures. Transmission electron microscopy mapped associated elements and the mineral hausmannite, a manganese oxide. The authors argue that the combined structural, chemical and mineral evidence supports a blood-derived origin.
Curtin’s research announcement proposes that rapid burial in a low-oxygen, microbe-rich environment and mineral stabilization helped preserve the traces. This is a proposed preservation pathway, not an observation of the fossilization process happening.
The cell identification is being scrutinized
In independent expert interviews with ABC, paleontologist Mary Schweitzer questioned whether the structures’ size and shape convincingly establish red blood cells, while finding the chemical evidence more persuasive. Mauricio Barbi considered the structures consistent with red blood cells but emphasized that identification still involves interpretation.
These responses are expert assessments, not a published replication. The evidence deserves examination without treating “strongest ever” or “unequivocal” as settled consensus.
What the discovery does not establish
Mineralized shapes and heme-related molecules do not amount to a sample of functional blood. Heme is a component associated with hemoglobin; detecting it does not establish preservation of the complete original protein. Likewise, collagen-related amino acids do not by themselves establish an intact collagen protein.
In an interview with Reuters, Grice explicitly said the research does not document dinosaur DNA. Small molecules and mineralized structures have different preservation histories from genetic material.
Why this belongs in MKP
MKP interpretation: The interesting question is how much biological information fossils retain, and how confidently each measurement can be linked to the original animal. Imaging and chemistry can reinforce one another, while still leaving alternative explanations to test.
Museum specimens can support new research as analytical methods improve. The value of a new result depends on its controls and reproducibility as well as its striking age.
Discussion questions
- What evidence would distinguish a mineral cast of a cell from an unrelated mineral structure?
- Why analyze surrounding rock as well as the bone?
- How do detecting a molecule, identifying a cell and recovering DNA differ?
Sources
- Grice and colleagues: Heme signatures in mineralized red blood cells within vascular canals of a 115-million-year-old dinosaur bone, PNAS, November 2, 2026. Primary study.
- Curtin University research announcement, reproduced by The National Tribune, dated November 3 in Australia.
- ABC Science: interviews with Grice, Schweitzer and Barbi, dated November 3 in Australia. Source for the expert assessments above.
- Reuters: interview with Grice and reporting on the study, November 2, 2026.