First Fossil Brain: Shark Relative That Lived 300 Million Years Ago Yields Very Rare Specimen

A 300-million-year-old brain of a relative of sharks and ratfish has been revealed by French and American scientists using synchrotron holotomography at the European Synchrotron Radiation Facility ESRF . It is the first time that the soft tissue of such an old fossil brain has ever been found.A s in many scientific discoveries it all happened by chance. The team from the National Natural History Museum in Paris MNHN in French the ESRF and the American Museum of Natural History in New York was using the synchrotron to study one of the few skulls of an iniopterygian fish that has maintained its three dimensions most of them are squashed . Inopterygians are an extinct relative of sharks and ratfish and used to live on the shallow and muddy marine ground. They were not bigger than 50 centimeters. The scientists used the technique of absorption microtomography to study different samples. One sample stemming from Kansas US revealed a peculiar structure it was denser than the surrounding matrix that fills the braincase and which is made of crystalline calcite. In order to elucidate its structure in detail they decided to use a second technique X-ray holotomography. Surprisingly the results showed a symmetrical and elongated object placed in the same position as a brain would have been. The 3D reconstruction showed different parts of the brain such as the cerebellum spinal cords or optic lobes and tracts among others. The only part the researchers couldn t spot was the forebrain perhaps too thin to become mineralized. Further analysis of the fossil indicated that the area where the brain-like structure reaches the surface of the sample reveals a high concentration of calcium phosphate whereas the surrounding matrix is almost pure calcium carbonate. The mineralization of the brain is according to the main author of the paper Alan Pradel from the MNHN "due to the presence of bacteria that covered the brain shortly before decay and induced its phosphatization".  ...

via First Fossil Brain: Shark Relative That Lived 300 Million Years Ago Yields Very Rare Specimen.