Scientists from the University of Michigan have uncovered the oldest known fossilized brain of a vertebrate animal during a study of a ray-finned fish sample from the Manchester Museum in England. The extinct species, Coccocephalus wildi, lived about 319 million years ago and was found in a coal mine in Lancashire. The unique fossil was loaned for a project led by the University of Michigan, which uses modern imaging technology to study the anatomy of extinct ray-finned fish.

The discovery was detailed in a paper published in Nature and shows that much of what was previously believed about brain evolution may need to be reevaluated. The fossilized anatomy includes the brain and cranial nerves, which have been preserved by the replacement of the original structure with hard mineral, likely pyrite.

Lead author, doctoral student Rodrigo Figueroa, stated that this “superficially unimpressive and small fossil” not only provides the oldest example of a fossilized vertebrate brain but highlights the importance of examining extinct species in evolutionary processes.