World's oldest preserved brain discovered in a Lancashire coal mine

The world’s oldest surviving vertebrate brain has been found in a 320-million-year-old fossilized fish discovered in a Lancashire coal mine.

The fossil was found at Carre Heys near Trawden in 1925 but has since been gathering dust in the Manchester Museum archives.

It wasn’t until a transatlantic team of scientists decided to send the fossil in for a CT scan that its hidden secret was revealed.

The skull appeared “superficially nondescript” at first, but the X-ray gave a “stunning insight” into the development of the fish’s brain, revealing cranial nerves up to 2.5 cm long.

From these scans, scientists believe the fish would have been between six and eight inches long.

The world’s oldest surviving brain was found in a 320-million-year-old fossilized fish found in a charcoal at Carre Heys near Trawden, Lancashire in 1925

Although only his skull was recovered, scientists believe it would have been six to eight inches long. Pictured: CT scan of the skull of Coccocephalus wildi showing the fossilized brain and associated structures

Judging by the shape of its jaws and teeth, it was likely a carnivore, according to the research team.

The fish was a Coccocephalus wildi, an early ray-finned fish about the size of a bream that swam in an estuary and likely fed on small crustaceans, aquatic insects, and cephalopods, a group that now includes cuttlefish, cuttlefish, and cuttlefish.

Lead Author Dr. Sam Giles of the University of Birmingham said: “This unexpected discovery of a three-dimensional vertebrate brain gives us an amazing insight into the neural anatomy of ray-finned fish.

“It shows us a more complicated pattern of brain development than is suggested from living species alone, and allows us to better define how and when modern-day bony fish evolved.”

“Comparisons with living fish showed that the brains of Coccocephalus most closely resemble the brains of sturgeon and paddlefish, which are often referred to as ‘primitive’ fish because they differed from all other living ray-finned fish more than 300 million years ago.”

The fossil was of a fish known as Coccocephalus wildi — an early ray-finned fish about the size of a bream that swam in an estuary and likely fed on small crustaceans, aquatic insects and cephalopods, a group that now includes squid, cuttlefish and squid

Researchers said while the skull initially looked “superficially nondescript,” it gave a “stunning glimpse” into the development of the brain in the fish, revealing the brain and cranial nerves, which were an inch long

How are fossils formed?

Very specific circumstances and conditions are required for the formation of fossils, since dying animals in most cases decompose.

Almost all fossils come from sea creatures because they lived in the sea and are quickly buried in sand or mud after they die.

This slows down the rate of degradation since less oxygen is available.

Often only the teeth or bones remain as the animal’s soft parts such as skin tissue and muscles rot away.

Scavengers can also feed on the remains of the dead animal, meaning little is left.

This is why the discovery of the brain in the skull of Coccocephalus wildi is so interesting.

It gives a glimpse into the brains of early species and shows how the species evolved over time.

Source: Natural History Museum

The research, published in the journal Nature, sheds new light on how soft parts of fossils are preserved in backbone animals and provided exciting insights into the evolution of species.

Soft tissues, like the brain, usually decay very quickly, meaning very few fossils of these body parts remain.

Because of this, most fossils found in museums are hard body parts such as bones, teeth, and shells.

But when this fish died during the fossilization process, the soft tissues of its brain and cranial nerves were replaced with a dense mineral that preserved its three-dimensional structure in minute detail.

Researchers said when it died it was likely buried quickly in low-oxygen sediments.

Such environments can slow down the decomposition of soft body parts.

Lead author and University of Michigan graduate student Rodrigo Figueroa added: “The fossil captures a time before a characteristic feature of ray-finned fish brains evolved, giving a clue as to when this feature evolved.

“This superficially inconspicuous and small fossil not only shows us the oldest example of a fossilized vertebrate brain, but it also shows that much of what we thought about the evolution of brains from living species alone needs to be revised.”

Lead author Professor Matt Friedman of the University of Michigan said: “One important conclusion is that these types of soft tissues can be preserved, and they can be preserved in fossils that we’ve had for a long time — that’s a fossil that’s been around for over.” Known for 100 years.”

Scientists weren’t looking for a brain when they began examining the fossil, but instead discovered a definite object inside the skull.

It displayed several features found in vertebrate brains, including being bilaterally symmetrical, containing cavities resembling ventricles in appearance, and having multiple filaments extending to openings in the braincase resembling cranial nerves in appearance , migrating through such channels in living species.

Since the skull fossil is the only known specimen of its kind, further destructive tests could not be carried out.