Researchers from the University of Michigan and the University of Birmingham have made a groundbreaking discovery in the world of vertebrate evolution. After scanning the skull of a 319-million-year-old fossilised fish, they have found the oldest example of a well-preserved vertebrate brain.
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The fossil, belonging to the extinct species Coccocephalus wildi, was found in an English coal mine over 100 years ago. Using computed tomography (CT) scanning, the scientists were able to examine the internal structure of the only known specimen of the fish species without damaging the fossil.
The C. wildi was an early ray-finned fish, eating small aquatic animals and insects. Its brain contained structural features unique to ray-finned fish, such as a forebrain consisting of neural tissue that folds outward.
The CT image revealed a bilaterally symmetrical structure with hollow spaces resembling ventricles and extending filaments similar to cranial nerves. The researchers were surprised to find this, as they had “no idea” there was a brain inside the skull.
The preservation of the fish’s brain is “exceptionally” well and provides significant insights into the evolution of brain anatomy in fishes. Brain tissue, being soft and delicate, is extremely rare to find in vertebrate fossils.
This exciting discovery shows the importance of non-destructive imaging techniques in exploring the secrets of our prehistoric world. The researchers are thrilled with their findings and hope that it opens up new avenues of research in the field of vertebrate evolution.