A study published in PNAS reports the detection of heme-related molecules and ellipsoidal microstructures within the hind limb of an Aratasaurus museunacionali fossil.
By Hermes-Vector AI Desk
Also in: Português
Researchers studying a 115-million-year-old dinosaur bone report finding microscopic structures resembling red blood cells and chemical evidence of heme, a molecule in hemoglobin. The study, published in the journal Proceedings of the National Academy of Sciences, focused on the hind limb of Aratasaurus museunacionali, a theropod dinosaur from the Early Cretaceous.
The fossil was recovered in 2008 from the Mina Pedra Branca site in the Romualdo Formation of northeastern Brazil. Within the bone's vascular canals—microscopic tubes that once carried blood vessels and nerve fibers—the team identified numerous oval-shaped microstructures. These structures average approximately 23 micrometers in length and 20 micrometers in width.
To investigate the origin of these structures, the team used high-performance liquid chromatography coupled with mass spectrometry. This analysis identified heme B and a chemically altered derivative known as 3,8-diethyl heme B. The researchers also detected amino acid building blocks associated with collagen. To confirm the heme originated from the dinosaur rather than the surrounding rock, the team analyzed the sedimentary matrix, which contained porphyrin signatures associated with chlorophyll and bacteriochlorophyll rather than heme.
The researchers suggest that the preservation of these biological traces was aided by specific environmental and mineral conditions. The team proposes that the dinosaur was rapidly buried in a low-oxygen, microbially rich environment shortly after death.
Additionally, the study identified the presence of hausmannite, a manganese oxide mineral, in association with the structures. The authors suggest that this mineralization may have helped stabilize and preserve the cellular structures and their associated molecular components during fossilization.
While the study's authors describe the findings as a "landmark discovery," some experts have raised questions regarding the interpretation. Mary Schweitzer, a professor emeritus at North Carolina State University, stated that the findings "do not meet established standards for identifying fossilized blood cells." Schweitzer noted that the structures' size and shape may not align with red blood cells in living relatives like birds or crocodilians, and pointed out that hausmannite is not found in living red blood cells.
Timothy Cleland, a physical scientist at the Smithsonian Institution’s Museum Conservation Institute, noted that finding heme is not equivalent to finding DNA. He explained that "heme and DNA are different molecules, and they would fossilize in bone in different ways."
If these findings are confirmed through further research, they could provide a "molecular window into the physiology of long-extinct animals," according to lead author Kliti Grice, an organic geochemist at Curtin University. This could allow scientists to investigate dinosaur metabolism, oxygen transport, and activity levels. The research also suggests that significant molecular information may remain hidden in museum collections worldwide, waiting for advanced analytical techniques to be applied.
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This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.
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Researchers have identified mineralized red blood cells and heme molecules in the limb bone of an Aratasaurus museunacionali fossil from Brazil.
