An international research team has discovered fossilized red blood cells, hemoglobin-derived biomolecules and amino acids from collagen protein inside the bones of a dinosaur that lived approximately 115 million years ago in Brazil. The unprecedented discovery opens new avenues for studying ancient life and challenges existing assumptions about how long fossils can preserve their biological components. The researchers, led by Australia's Curtin University, said the remains were discovered inside the limb bones of a theropod dinosaur known as Aratasaurus museunacionali, whose fossils were found in northwestern Brazil. The findings were published Monday in the journal Proceedings of the National Academy of Sciences (PNAS). Analyses revealed large numbers of preserved red blood cells within the bones' vascular canals. For the first time, researchers were able to establish the presence of hemoglobin-derived chemical compounds inside these cells by detecting heme, the component of hemoglobin responsible for binding and transporting oxygen. The finding provides confirmed chemical evidence of fossilized blood remnants, unlike previous studies that identified structures resembling red blood cells in fossils but could not conclusively establish their chemical nature. The discovery surprised researchers because the preservation of delicate biological components, such as red blood cells and hemoglobin molecules, over 115 million years challenges scientific assumptions about how long these materials can survive degradation. The researchers described the identification of heme-derived molecules within red blood cells of such extraordinary age as a remarkable discovery and a significant milestone in paleontology. They added that the findings not only expand the fossil record of blood remnants but also provide a direct molecular window into the physiological characteristics of extinct animals, helping scientists better understand their biology and the environments in which they lived. The study explained that the red blood cells had been mineralized by hausmannite, a mineral that acted as a natural time capsule, helping stabilize cellular structures and biological components, including amino acids associated with collagen protein, and protecting them from degradation over millions of years. Researchers believe this exceptional preservation resulted from the dinosaur's carcass being rapidly buried after death in a low-oxygen environment rich in microorganisms. These conditions may have helped preserve the biological components within the bones. The researchers said the findings challenge long-standing scientific assumptions that biomolecules such as hemoglobin could not survive over extended geological timescales. They also open new avenues for investigating the evolution of blood and metabolic processes, potentially offering insights into the activity levels of ancient animals. According to the team, the study redefines the limits of molecular preservation across vast periods of time, even under harsh environmental conditions. The findings may also have implications for astrobiology, potentially helping scientists develop methods to search for evidence of ancient life beyond Earth.
