Scientists say they have discovered "mineralized red-blood-cell-like structures" in a 115-million-year-old dinosaur fossil. The discovery is backed by the detection of heme, an iron-rich molecule in hemoglobin, which is the protein in red blood cells that carries oxygen and gives said cells their color. The findings were described in a paper in the Proceedings of the National Academy of Sciences, and they may represent the oldest red blood cells found in a dinosaur fossil.
"The evidence is best described as a combination of mineralized red-blood-cell-like structures and preserved molecular remnants derived from blood, including heme-related compounds," Kliti Grice, the paper's lead author and a geochemist at Curtin University in Australia, told Newsweek via email. "The original cells underwent decay, mineralization and extensive diagenetic alteration. Their shape, dimensions and composition would therefore not be expected to match those of fresh cells from a living animal," she added.
The study did not report liquid blood, preserved DNA or intact hemoglobin. The discovery was made while analyzing a hind leg bone of an Aratasaurus museunacionali, a meat-eating dinosaur that lived in the Cretaceous period. The dinosaur was estimated to have been about four years old, 3.12 meters long and roughly 34 kilograms.
It was discovered in a mine in northeastern Brazil in 2008 and had originally gone to the country's National Museum in Rio de Janeiro. Experts sent it to Grice and colleagues in 2024, who then investigated the specimen. Looking at the fossil slices under a high-resolution microscope after using hydrochloric acid to remove the surrounding rock, they found numerous structures that resembled red blood cells.
Grice told Newsweek the mineralized structures still retain recognizable chemical information, something she said is "remarkable." "The cells are not preserved in their original biological state, but components of their original biological identity appear to have survived within a mineralized fossil framework," she added. "The interpretation does not rest simply on detecting iron, since iron is common in geological materials," Grice continued. "It rests on identifying diagnostic molecular architecture associated with heme which contains iron, in the correct anatomical setting and alongside structures resembling mineralized blood cells." The discovery provides a "powerful framework" for examining other exceptionally preserved fossils by using the same approach, Grice said.
"The next step is to target specimens with promising preservation features, particularly fossils showing mineralized vascular structures, microbial-mat associations or manganese-rich mineralization, and analyze them using microscopy, spectroscopy, mineralogy and molecular organic geochemistry," she added. Material like this could be more widespread than was previously thought. "It may be genuinely rare because exceptional preservation requires a very specific sequence of biological, microbial, mineralogical and geochemical conditions," Grice said.
Extract — continue reading at the source.
