Researchers Report Heme and Cell-Like Structures in 115-Million-Year-Old Dinosaur Bone

An international research team has reported finding heme B and small cell-like structures inside a 115-million-year-old dinosaur bone, according to a study published Nov. 2 in the Proceedings of the National Academy of Sciences. The bone belongs to Aratasaurus museunacionali, a meat-eating dinosaur that lived about 115 million years ago in what is now northeastern Brazil. The fossil was excavated in 2008 at Mina Pedra Branca in northeastern Brazil, within the Romualdo Formation, and includes parts of the right femur, tibia, and foot of a juvenile about 4 years old that would have measured roughly 10 feet (3.1 meters) long. The species was formally named in 2020. The specimen went first to a paleontology museum in Santana do Cariri, then to the National Museum of Brazil in Rio de Janeiro. It survived the 2018 fire that destroyed much of that museum's collection. Its name honors the institution.

What the Researchers Found

Under the microscope, the team found many small, ellipsoidal structures packed inside the bone's vascular canals, where blood once flowed. "When we examined the Aratasaurus bone at the microscopic and chemical level, we encountered structures that were remarkably cell-like," Kliti Grice, an organic geochemist at Curtin University in Australia, told ScienceAlert.

Using high-performance liquid chromatography and mass spectrometry, the researchers found the bone extract was dominated by heme B, the iron-bearing molecule that lets red blood cells carry oxygen. Elemental maps showed iron, carbon and nitrogen concentrated on the cell-like structures, while the surrounding bone held mostly phosphorus, calcium and fluorine. According to New Atlas, an altered form of heme was about 90 times more abundant than intact heme B.

The team credits an unusual burial for the preservation. The animal appears to have settled into a shallow, nearly oxygen-free setting covered by microbial mats. A manganese oxide mineral called hausmannite then coated the structures, acting like a natural time capsule, according to a Curtin University release.

Contamination Checks and Skepticism

The researchers said they looked for the usual impostors and did not find them. They reported no microbial filaments, spores or biofilms that could mimic cells. They found no pyrite crystals or sediment grains of similar size. Most importantly, the surrounding rock carried signatures of chlorophyll and bacteriochlorophyll from photosynthetic microbes, but no heme B. That contrast suggests the heme came from the bone rather than the burial environment.

The team also detected amino acids associated with collagen. Grice told Reuters the work is not "a vial of dinosaur blood," and she has said the findings do not mean dinosaur DNA survived.

Mary Schweitzer, a molecular paleontologist at North Carolina State University who was not involved in the study, welcomed the chemical approach but disputed the interpretation. "I am not convinced that the images they figure are remnant RBCs," she told Live Science. Schweitzer noted that red blood cells in birds and reptiles, the dinosaurs' closest living relatives, carry a nucleus that creates a bulge. The Aratasaurus structures appear concave, with no bulge, and are smaller than most non-mammalian red blood cells.

Why it matters

The evidence picture is mixed. This is a peer-reviewed laboratory study of a single specimen, published in a major journal. It found strong chemical evidence of heme associated with cell-like structures. It did not prove those structures are intact red blood cells, and it did not recover proteins or DNA in usable form. "The immediate priority is replication," Grice said. The next steps are replication on additional Aratasaurus material and on other fossils from the same Brazilian deposits. Until then, the find is best described as the strongest chemical case yet for dinosaur blood remnants, not a settled answer.

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Sources

• natureworldnews.com: Heme Molecules and Cell-Like Shapes in a 115-Million-Year-Old Dinosaur Bone Test What Fossils Can Preserve
• demokratis.co.id: Researchers Detect Heme in 115 Million-Year-Old Dinosaur Bone

This article was drafted with AI assistance and checked against the sources above. Company claims are reported as claims. Cover image is AI-generated.