319-million-year-old fish retains ‘oldest animal brain with backbone’
A 319-million-year-old fossilized fish skull that was scanned with CT scans and discovered in a coal mine in England over a century ago has revealed the oldest specimen of a well-preserved vertebrate brain.
Scans revealed that the creature’s skull contained a cerebrum and nerves at the back of the brain.
Scientists from the University of Birmingham and the University of Michigan believe the discovery opens a window into the formation of the brain and nervous system, as well as the early evolution of the main group of fish living today, the ray-finned fish.
319 million year old fish preserved the earliest vertebrate fossil brain: https://t.co/Nmw9RLXHOU https://t.co/IQAF8A0fxG
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Scientists suggest that the finds shed new light on how the soft parts of fossil animals with spines were preserved.
Lead author Dr Sam Giles of the University of Birmingham said: “This unexpected discovery of a preserved vertebrate brain in 3D gives us an amazing insight into the neuroanatomy of ray-finned fish. It tells us about a more complex pattern of brain development than has been thought of in living species alone, allowing us to better determine how and when the evolution of bony fish has taken place up to the present.
The CT-scanned brain analyzed for the new study belonged to Coccocephalus wildi, an early ray-finned fish that swam in the estuary and likely fed on small crustaceans, aquatic insects and cephalopods, which today includes squid and octopuses. And in ray-finned fish, the spine and fins are supported by bony rods called rays.
Dr. Giles added: “Comparisons with living fish have shown that the brain of Coccocephalus wildi is very similar to that of sturgeon and copepods, which are often called primitive fish because they diverged from all other living ray-finned fish over 300 million years ago. .”
While soft tissues such as the brain naturally decompose quickly when this fish died, the soft tissues of its brain and cranial nerves were replaced in the process of fossilization with a dense mineral that preserves the three-dimensional structure of the soft tissues in great detail. fabrics.
“This small fossil not only shows us the oldest fossilized vertebrate brain, but also shows that much of what we thought about brain evolution only among living species needs to be rethought,” said lead author Rodrigo Figueroa, also from the University of Michigan. .
“The important takeaway is that these types of soft parts can be preserved, and they can be preserved in the fossils that we have, as far back as the known fossil, for example, more than 100 years ago,” said the senior author. Matt Friedman of the University of Michigan.
According to an article published in the journal Nature, this fossil from England is the only known specimen of its kind, so scientists have had to use methods that do more than destroy it.
It also states that the fossil skull was loaned to the University of Michigan from the Manchester Museum.
And it was mined from the surface of the Mountain Fourfoot Colliery in Lancashire, and this discovery was first discovered scientifically in 1925.
Scientists believe that Coccocephalus wildi was six to eight inches (15 to 20 cm) long. Judging by the shape of its jaws, it could have been a predator.
And when the fish died, they could be quickly buried in low-oxygen sediment, an environment that could slow the decomposition of soft body parts.
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