The Royal Ontario Museum has revealed a cache of fossils containing the brain and nervous system of a marine predator estimated to be about half a billion years old.
This marine animal, called Stanleycaris, was found in the Burgess Baby Layer, a layer of fossil-bearing sediments found in Canada.
amazing treasure
Stanlicaris belongs to the order Actinomycetes;
It is one of the extinct evolutionary branches of arthropods that are considered distant from modern insects and spiders.
Stanlicaris found in the layer of a Burgess baby (Jean-Bernard Caron, Royal Ontario Museum)
The results of this discovery, which shed light on how arthropod brains evolved, including vision and head skeleton evolution, were published in Current Biology on July 8.
The researchers found this strange animal within an amazing treasure trove of fossils dating back 506 million years.
Despite this long period of time, the good state of preservation of these fossils showed that 84 of them still contain well-preserved remains of the brain and nerves.
Therefore, it was inside the head of "Stanlicaris" that most intrigued researchers about this strange animal.
According to the report published by the "Eurek Alert" website, commenting on the study, Joseph Moisiuk mentioned;
The study leader at the University of Toronto said, "Although the discovery of fossilized brains dating back to the Cambrian period (the first Paleozoic spanning from 541 to 485 million years ago) is not new, the new discovery is in a well-preserved state. on which these samples were found, in addition to their large number.
Brain "Stanlikaris consists of a frontal brain connected to the eyes, and a midbrain connected to the claws (Royal Ontario Museum)
in-depth details
Thanks to this good preservation condition, scientists can "describe the smallest details related to the visual centers that serve the large eyes of the organism, and we can also track the nerves that reach the extremities of the organism, as we can see these details clearly as if the animal had died yesterday," Moisiuk said. .
Today, arthropods, like insects, have brains consisting of an anterior, middle, and posterior third brain.
In contrast, the new fossils show that the brain of Stanlikaris consists of two parts.
Forebrain (which connects to the eyes) and midbrain (which connects to the front claws).
"We thus conclude that the two-part head and brain have ancient roots in the lineage of arthropods, and that their evolution probably preceded the 3-part brain that characterizes all organisms belonging to this diverse animal phylum," Moiseuk states.
Stanlicaris has a large central eye on the front of its head and two peripheral eyes (Sabrina Capelli, Royal Ontario Museum)
In addition to the terminal eyes, stanlicaris has a large central eye in the front of its head, which has not been observed before in radiotooth animals.
Jean-Bernard Caron, curator of invertebrate palaeontology at the Royal Ontario Museum and co-author of the study, notes, "These animals look more exotic than we thought, as we did not expect Stanlikaris to have a large third eye. This indicates that the earliest arthropods did indeed evolve a variety of systems complex visual as many of its contemporary relatives."
small predator
It is noteworthy that during the Cambrian period, a group of the largest animals that existed at that time were rays.
For example, anomalocaris - or what is known as anomaly shrimp - reached a length of at least one meter.
The stanlikaris had a wonderfully round mouth lined with teeth (Jean-Bernard Caron, Royal Ontario Museum)
In contrast, stanlikaris did not exceed 20 centimeters in length, making it a small animal relative to its group.
However, most animals at that time were no longer than a finger.
Thus, stanlikaris may be a surprising predator, as the sensory and visual systems of this creature were so sophisticated that it was able to hunt small prey very efficiently in the dark.
In addition to the large compound eyes, the "Stanlikaris" had a wonderfully round mouth lined with teeth, and front claws connected to an amazing set of nerves.
The body of "Stanlikaris" was flexible and segmented and equipped with sides to help it swim.