Fossils 525 million years old may reveal the oldest sample of the brain

A tiny sea creature, less than 1.5 cm across, could rewrite the history of how brains evolved and resolve a decades-old scientific dispute.

At least that is the conclusion of the researchers behind the study which was published in the scientific journal ScienceAn international team of experts has examined 525-million-year-old fossils found in China and discovered what they believe is the oldest sample of brain tissue in the world.

More surprises

The fossil contains the remains of a worm-like arthropod called the Cardiodictyon series. It was embedded in a number of rocks from Yunnan Province in southeastern China, which were discovered in 1984.

At a full 1.5 cm long, the fossil is too small to be X-rayed. But now researchers have succeeded in looking at the fossil remains with the help of a special imaging technique that filters out light at different wavelengths and thus maps the structure of the fossil.

The amazing thing is that the brain of a small primitive animal that moved around the sea floor about half a billion years ago is still preserved. It was also found to be created from three separate components of the nervous system.

Scientists previously thought that the brains of these early creatures were divided into repeating segments (or segments) of nervous structures called ganglion ganglia, much like the body’s nervous system.

Settles the heated controversy

According to the researchers, the discovery is the answer to a long and heated debate about the origin and formation of the head in arthropods, the most species-rich group in the animal kingdom that includes insects, crustaceans, spiders and centipedes.

They explain how biologists had discovered since the 1880s that the bodies of arthropods repeat themselves in a series of repeating, uniform pieces, and that they essentially transferred this discovery to the head, which they also believed to be part of the same system.

But now the study shows The tiny, fossilized sea creature whose early head and brain were neither part of the repeating unitary parts. Therefore, according to the researchers, it also indicates that the brain and nervous system of the body have evolved separately.