Fish are generally not intelligent creatures with tremendous mental abilities. In particular, many people believe that goldfish have a memory capacity of three seconds, but this is not true. Another fish's brain recently came under the spotlight for a different reason. A 319-million-year-old fish fossil in the Manchester Museum has shown that its skull contains a brain and cranial nerves, which are the oldest well-preserved vertebrate brains ever discovered.
This rare find excited researchers around the world and is described in an article in the journal Nature.
The fossil, discovered over 100 years ago in a mine in Lancashire, UK, was encased in soapstone. It has since been in the museum, but was recently examined by researchers. Known as Coccocephalus wildi, this is the only specimen of its species that has been found. Although only one skull has been found, the fish was likely six to eight inches long.
Not initially looking for a brain, researchers used computed tomography to find a strange object inside the skull. Like the vertebrate brain, this object was bilaterally symmetrical, contained cavities, and had many filaments (like cranial nerves). The brain curves inward, unlike modern ray-finned fish. Vertebrate brains decay quickly, so it's unusual to find fossilised specimens. Probably the dead animal was quickly covered with oxygen-poor sediments.
Lead author Sam Giles of the University of Birmingham said in a statement: "This unexpected discovery of a three-dimensionally preserved vertebrate brain gives us a remarkable insight into the neural anatomy of ray-finned fish. This tells us something about a more complex model of brain evolution than that proposed only from living species, allowing us to better determine how and when modern teleosts evolved."
"Comparisons with modern fish have shown that the coccocephalic brain most closely resembles that of sturgeon and paddlefish, which are often referred to as 'primitive' fish because they differed from all other living ray-finned fish over 300 million years ago," he said. marked. The modern world's 30,000 species of ray-finned fish make up half of all vertebrate species on this planet.