‘Backward’ brain of ancient sea creature hints spider ancestors evolved in the ocean

0 0 3 minutes read

‘Backward’ brain of ancient sea creature hints spider ancestors evolved in the ocean

https://www.profitableratecpm.com/f4ffsdxe?key=39b1ebce72f3758345b2155c98e6709c

An unusual fossil brain suggests that the ancestors of spiders and other arachnids may have scuttled once around the sea, rather than on earth, as has been a new study for a long time.

The fossil shows that certain characteristics of the brain of an animal now extracted under the name Mollisonia symmetrica are arranged back compared to those of the most modern arthropods, a large group of invertebrates which includes animals such as insects, crustaceans and central and centrals. However, Mr. SymmetricaThe brain is similar to those of the arthropod group: arachnids, a class that includes spiders, scorpions and ticks. This difference suggests that the sailor Mr. Symmetrica is a former ancestor of modern arachnids, the researchers reported Tuesday, June 22 in the journal Current biology.

“It is still vigorously debated where and when the arachnids appeared for the first time, and what type of chélérates were their ancestors, and if they were sailors or semi-aquatic like horseshoe crabs”, co-author of the study Nicolas StrausfeldA teacher specializing in arthropod neuroscience at the University of Arizona, said in a statement. The Chélérats constitute a large group of arthropods which includes arachnids and horseshoe crabs.

Chélérères as Mr. Symmetrica branched out from other arthropods at the Middle Cambrian period. THE Mollisonia The genus, which has four known species, lived between 515 million and 480 million years. Species Mr. Symmetrica had a body segmented like that of a scorpion, a round shell and six pairs of appendages for moving and hunting.

Although scientists are not exact exactly when the arachnids have extended further from other Chélérats, arachnids have existed for about 400 million years. So far, their fossil file has suggested that they lived exclusively on earth.

In the new study, researchers have studied the fossilized brain and the central nervous system of a Mr. Symmetrica Specimen of the Burgess shale formation of the Canadian Rockies. They found that the animal’s brain was not organized like that of a horseshoe crab like Limulus. Instead, certain regions of his brain seem to be arranged in the opposite direction compared to those of other arthropods, similar to the way the brains of modern spiders are developed. This suggests that arachnids have evolved and diverge from horseshoe crabs earlier than scientists had thought of it.

A comparison side by side of the brain of a horsesome crab, the mollisonia fossil and a modern spider reveal that the organization of the three regions of the mollisonia brain is reversed compared to the horseshoe crab, and resembles the arrangement found in modern spiders.

The brain of an iron iron crab (left), Mollisonia symmetrica (in the middle) and a modern spider (right). Notice how the three regions of the brain of the ancient creature (green, magenta and blue) are reversed compared to horseshoe crabs. Instead, it looks like the brain of modern spider. (Image credit: Nick Strausfeld)

“It’s like the Limulus-The type brain seen in Cambrian fossils, or the brain of ancestralia and [day] Crustaceans and insects have been returned upside down, which we see in modern spiders, “said Strausfeld.

In relation: Why do spiders have 8 legs?

This opposite arrangement is exclusive to arachnid brains in modern animals, suggesting that Mr. Symmetrica was a first arachnid and that this unique arrangement has evolved in the ocean rather than later. Studies on the brains of existing spiders suggest that the inverted configuration allows spiders to coordinate many aspects of the predatory movement, including their stealth, their speed and their dexterity.

“The arachnid brain is different from any other brain of this planet, and he suggests that his organization has something to do with calculation speed and control of motor actions,” said Strausfeld.

Imagery showing the anatomical characteristics of the Mollisonia fossil

Detailed images of Mollisonia symmetricaThe brain over 500 million years ago. (Image credit: Nick Strausfeld)

The stealth and speed of spiders as hunters on earth may have contributed to the evolution of insect wings, which would have allowed the prey to escape, added Strausfeld.

“Being able to fly gives you a serious advantage when you are prosecuted by a spider,” said Strausfeld. “However, despite their air mobility, insects are still taken in their millions of exquisite silk paintings shot by spiders.”

To determine if the similarities between Mr. SymmetricaThe brain and those of modern spiders came from a common line or a simple coincidence, the researchers used a computer program to estimate the probability that the two are linked. To do this, they compared the brain and body features of several living and extinct arthropods. The analysis suggested that the Mollisonia The line finally evolved in the Arachnid group, which means that it may have led to “the most successful arthropod predators on the planet”, wrote researchers in the study.