WATCH: World's Oldest Vertebrate Brain Found In 319-Million-Year-Old Fossil

World's Oldest Vertebrate Brain Found In 319-Million-Year-Old Fossil. Scientists have discovered the fossilised brain of a fish in a 319-million-year-old fossil.

The rare finding was originally found at the Mountain Fourfoot coal mine in Lancashire, England more than a century ago. It has since been safely stored at the Manchester Museum and scientists are still learning from it 125 years later.

Now, a CT scan of the fossil has revealed it contains the "oldest example of a well-preserved vertebrate brain”. The brain and cranial nerves are about an inch long and belong to the extinct Coccocephalus wildi (C. wildi). This was an early ray-finned fish that likely ate small crustaceans, cephalopods, and aquatic insects while swimming around estuaries.

According to the authors of the University of Michigan-led study, the discovery "opens a window into the neural anatomy and early evolution of the major group of fishes alive today.”

While the small fossil fish may appear "superficially unimpressive," it shows that "much of what we thought about brain evolution from living species alone will need reworking," Rodrigo Figueroa, one of the lead authors of the study, said.