Fossilized brains of marine creatures that lived during the Cambrian explosion more than 500 million years ago were found. A discovery that will allow scientists to understand how ancient brains evolved into the actual complex command centers they are today.
Kerygmachela kierkegaardi lived in the oceans about 521 to 514 million years ago. These creatures were about 25 centimeters long, had large eyes and had 11 feather-shaped flaps on their sides allowing them to swim. They also had a long tail and long appendages on their round heads, which they used to grab their prey. Another thing, they also had a brain, consisting of a single segment. Fossils from Kerygmachela have been discovered before, but this is the first time that fossilized brains of these ancient animals have been found.
This new study, published in Nature Communications, describes the characteristics of these small brains, and the reasons why these new analyzes could reverse a widespread belief about arthropod ancestry. The team reports having here discovered 15 fossilized brains. And because the brains were composed of only one segment, it is assumed that they were less complex than those with three segments observed in distant ascendants of the creature, such as spiders, lobsters, and butterflies, suggesting then limited behavioral attributes.
If these results question the hypothesis that the common ancestor of all arthropods and vertebrates had three-segment brains, the team notes, however, that the creature clearly had enough brain power to survive in the Cambrian explosion. The researchers also note that the large eyes of this species represent an intermediate evolutionary stage between creatures with very simple eyes and those with much more complex eyes.
In other words, the animal probably had a more limited brain than previously thought. On the other hand, he had much better eyes than what was previously suggested in other studies. These fossils were found on the Sirius Passet site at the northern tip of Greenland. The researchers discovered them by prospecting plots of shale, which had then protected the fossils of the elements for millions of years, allowing the preservation of fossilized brains.