A fish that lived there are around 518 million years could change what science knows about the origins of vision in vertebrates. Fossils analyzed by researchers indicate that this animal — from the Myllokunmingia group — had four functional eyes, and not just two, as previously believed.
The study, on January 21, analyzed well-preserved remains found in China and identified two lateral eyes, similar to those of current fish, and two other visual organs positioned on top of the head.
These structures were linked to the so-called pineal complex, a region that today, in many vertebrates, is associated only with the perception of light and regulation of biological rhythm.
The surprise came when scientists found evidence that these extra organs also formed images. In the fossils, pigments, structures comparable to the retina and possible lenses were identified, suggesting that the animal had more sophisticated vision than any other vertebrate known from that period.
According to the researchers, this characteristic may have been an important evolutionary advantage in primitive marine environments, allowing predators and prey to be detected in different directions and light levels.
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Over time, these additional eyes would have lost their function of forming images, giving rise to the light-sensitive structures present in modern vertebrates.
It is hypothesized that the first vertebrates had more complex sensory systems than previously imagined.
The study raises new questions about how the vision evolved over hundreds of millions of years.
