We may have been wrong where spiders came from

Technically speaking, any living being on earth can follow its origin to the sea. Some of these most people crashed on land, developing to become many different species of animals and insects – including, scientists have been believed for a long time, spiders and their relatives.

A new study published today in Current biology It triggered the popular concept that spiders first appeared on land, instead suggested that these Arachnides and their relatives had arisen and evolved into the ocean. The team reached this conclusion by investigating the fossilized central nervous system of Soften symmetricallyA long burning animal from the Cambrius era (between 540 and 485 million years), considered the ancestor of the horseshoe crabs. SoftenThe brain structure is very similar to that of modern spiders and their relatives, not their alleged crab descendants.

“The discovery of an arachnid brain in such an ancient being as Soften suggests that the large groups of arthropods are now established then,  » Nick StrausfeldStudy the lead author and neurologist at the University of Arizona, Gizmodo told an email. He added that this « caught a new look at the question: where did Arakhnid develop for the first time? »

Until now, scientists have been adopted by the external characteristics of the fossils, similar to Arachnide, found in precipitated rocks formed on land-that modern spiders and their relatives develop on land. However, Strosfeld and his colleagues looked like the study inside a well preserved fossil of Softenwhich they did using an optical microscope and other depiction techniques to explore more detail its brain arrangements.

The team revealed several similarities between modern spiders and SoftenBut the most convenient characteristic was that of the central nervous system of beings. Unlike the insects, Arakhnid’s brains have a strange reverse structure in which « the anterior brain is located on the chains that control the movement of the legs, » Strosfeld explained. This is what makes the spiders and their relatives so « incredibly universal in their movements. » As the new survey shows, “the organization back is sufficient“ telling ”to demonstrate (this) SoftenThe brain arrangement describes those of living arachnides, « he said.

Other common features that the team finds include external similarities, such as joined limbs or nail -like nails. They have strengthened their hypotheses by conducting statistical analysis, comparing 115 anatomical traits in both alive and missing arthropods (which include arachnides) that placed Soften As the « sister » of contemporary arachnides, the authors reported in the study.

« It’s very interesting, but we still don’t know how it concerns the huge array of Arachnides other than spiders, » said Paul SeldonPaleontologist and arachnologist at the University of Kansas, who did not participate in the new job, in an email to Gizmodo. « It is clear that their conclusions regarding the phylogenetic (study of evolutionary history using visual signals) placement of Soften are compelling, but simply noted the beginning of a more increasing investigation. « 

It is probably premature to declare spiders as the sea of the sea, but the good news is that Strosfeld and his colleagues seem to be in this case.

« Most Cambrian fossils look very different from modern species, so it is really exciting when such external manifestations reveal something inside them – the brain and the nervous system – which tells a different story, » Stosfeld said. « Arachnides are a decisive characteristic of our biosphere, and we must pay attention to what they contribute to our well -being. »