The skull scan of a fossilised fish has led to the discovery of a 319-million-year-old brain

The oldest example of a well-preserved vertebrate brain has been discovered following the scan of the skull of a 319-million-year-old fossilised fish, a CNN report says. The latest find throws new light on the early evolution of bony fish. Researchers of the study published in the journal Nature on Wednesday said that the fossil of the skull belongs to the extinct Coccocephalus wildi and was found in a coal mine in England over 100 years ago.

Scientists from the University of Michigan in the US and the University of Birmingham in the UK used the nondestructive imaging technique of computed tomography (CT) scanning to look inside the skull and examine its internal bodily structure since the fossil is the only known specimen of the fish species.

The C. wildi was an early ray-finned fish. It had a backbone and fins supported by bony rods called "rays". It used eatsmall aquatic animals and insects, the researchers said.

The brains of ray-finned fish display contain structural features that are not seen in other vertebrates. There is a forebrain consisting of neural tissue that folds outward, according to the study. This tissue folds inward in other vertebrates.

The CT image showed an “unidentified blob,” a University of Michigan press release said.

A clearly defined structure with features found in vertebrate skulls were clearly visible. It was bilaterally symmetrical and contained hollow spaces similar in appearance to ventricles. It also had extending filaments resembling cranial nerves.

"This is such an exciting and unanticipated find," study coauthor Sam Giles told CNN.

Giles added that they had "no idea" there was a brain inside the skull when they thought about studying the skull.

"It was so unexpected that it took us a while to be certain that it actually was a brain. Aside from being just a preservational curiosity, the anatomy of the brain in this fossil has big implications for our understanding of brain evolution in fishes," she added.

Researchers say that unlike hard bones and teeth, brain tissue, which is soft and preserved in vertebrate fossils, is extremely hard to find.

The study said that the fish's brain was "exceptionally" well preserved.

(With inputs from agencies)

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