Researchers in Brazil have discovered what appear to be 115-million-year-old red blood cells in a dinosaur fossil.
The findings, published in the Proceedings of the National Academy of Sciences (PNAS), come from an analysis of a leg bone from Aratasaurus museunacionali, a small carnivorous dinosaur unearthed in 2008.
The international team, led by Kliti Grice of Curtin University in Australia, used electron microscopy and chemical analysis to identify spherical structures in the bone’s vascular channels that resemble red blood cells, alongside molecular traces of hemo—the oxygen-carrying component of hemoglobin.
Structures Inside Blood Vessels and Amino Acids Suggest Preserved Remains
The structures were found inside the bone’s tiny blood vessels, not in the surrounding sediment, making external contamination unlikely. The team also detected amino acids linked to collagen, a structural protein in tissues. “Detecting molecules derived from intact hemo in red blood cells from 115 million years ago is astonishing: it is truly a historic discovery,” Grice said in a university statement.
“In concrete, the samples contained preserved remains of hemo, the component of hemoglobin in charge of transporting oxygen, which ‘confirms, essentially, the existence of remains of fossilized blood,’ according to Kliti Grice, director of the Organic and Isotopic Geochemistry Center at the Australian Curtin University and one of the study’s authors.”
The study’s authors propose a unique preservation mechanism. The dinosaur was buried rapidly in an oxygen-poor environment rich in microbes, allowing the mineral hausmannite—a manganese oxide—to encase the structures, shielding them from decay over millions of years.
The scientific team, also made up of specialists from institutions in Japan, Brazil, and the United States, considers that this extraordinary preservation could be due to the dinosaur being buried quickly after dying in an environment with little oxygen and an abundant presence of microorganisms.
Scientists Find Cell-Like Shapes and Blood Markers in Dinosaur Bone
- Scientists found microscopic cell-like shapes and chemical blood markers in a dinosaur bone dating back 115 million years.
- The find could open a new window into studying the biology of extinct animals, though more proof is needed.
Scientific Scrutiny and Unanswered Questions
Not all experts are convinced. Mary Schweitzer of North Carolina State University questioned the identification. Dinosaur red blood cells should have a central bulge from a nucleus, but the observed structures are concave, more similar to human red blood cells, which lack nuclei.
The paleontologist Mary Schweitzer, of North Carolina State University, considers that there is still a lack of evidence to confirm that the structures found are red blood cells. The study’s authors themselves clarified they found no liquid blood or dinosaur DNA.
Global Impact on Paleontological Research
It suggests that under specific geochemical conditions, biomolecules like hemoglobin and collagen can persist for millions of years, offering insights into dinosaur metabolism, oxygen transport, and evolutionary biology. The discovery challenges the idea that certain biomolecules, such as components of hemoglobin, cannot be preserved for such long geological periods.
The research involved contributions from institutions in Japan, Brazil, and the United States. The bones were discovered in deposits of the Romualdo Formation, in the northeast of Brazil, and were first described in a scientific study published in 2020.
Researchers Must Replicate Findings to Confirm Structures and Chemical Signatures
The primary challenge ahead is independent replication of the findings. The scientific method requires that other labs using different analytical techniques confirm the presence of these structures and their biochemical signatures.
The debate highlights the cautious nature of science. While the chemical signals for hemo and collagen are compelling, the morphological identification of red blood cells remains contentious.
| Key Findings | Description |
|---|---|
| Structures Identified | Mineralized, elliptical microstructures resembling red blood cells, found within bone vasculature. |
| Chemical Markers | Presence of hemo (from hemoglobin) and amino acids associated with collagen. |
| Preservation Agent | Hausmannite (manganese oxide) in an anoxic, microbially active environment. |
| Age of Fossil | Approximately 115 million years old. |
References
- Proceedings of the National Academy of Sciences (PNAS) – Primary research publication.
