Researchers studying an Aratasaurus museunacionali fossil in Brazil have identified microscopic structures resembling red blood cells containing heme molecules.
By Hermes-Vector AI Desk
An international team of researchers has reported finding microscopic structures resembling red blood cells and chemical evidence of heme within a 115-million-year-old dinosaur bone. The study, published in the journal Proceedings of the National Academy of Sciences, focused on the hind limb of an Aratasaurus museunacionali, a theropod dinosaur from the Early Cretaceous.
The fossil was recovered from the Mina Pedra Branca site in the Romualdo Formation in northeastern Brazil. Within the bone's vascular canals—microscopic tubes that once contained blood vessels—researchers 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, a molecule central to the oxygen-carrying function of hemoglobin, and a chemically altered derivative known as 3,8-diethyl heme B. The researchers used Raman spectroscopy and transmission electron microscopy to confirm that these heme-related chemical signatures were located within the ellipsoidal microstructures.
The researchers suggest that the preservation of these biological traces may be due to specific environmental and mineralogical conditions. The team proposes that the dinosaur was rapidly buried in a low-oxygen, microbially rich environment shortly after death.
Additionally, the study identifies the presence of hausmannite, a manganese oxide mineral, in association with the structures. Lead author Kliti Grice, an organic geochemist and John Curtin Distinguished Professor at Curtin University, stated that the team believes this mineralization helped stabilize the cellular structures and associated molecular evidence during fossilization.
While the study provides multiple lines of evidence, the findings have met with some scientific skepticism. Mary Schweitzer, a professor emeritus at North Carolina State University, noted that the findings do not meet established standards for identifying fossilized blood cells. Schweitzer questioned if the size and shape of the structures sufficiently match those of living relatives and noted that hausmannite is not detected in living red blood cells.
Other experts have noted that the structures differ in size and shape from the red blood cells found in living birds and crocodilians. However, researchers noted that modern species may not be the best comparison for non-avian dinosaurs, and the cells may have changed shape after death.
Despite the debate, the researchers suggest this discovery could open new avenues for molecular-level paleontology. "It opens exciting new avenues for molecular-level paleontology, allowing us to investigate the evolution of blood, metabolism, and even activity levels in ancient animals," Grice said.
This research provides a potential proof of concept for using molecular and chemical analysis to uncover biological information in fossils that was previously thought to be lost over geological time. If similar preservation is found in other specimens, it could allow scientists to investigate the physiology of extinct animals with greater detail.
Sources
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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