A fossil suggests spider brains might have origins within the ocean : Short Wave : NPR

Illustration of what the Mollisonia animal would have seemed like on the time it lived, greater than 500 million years in the past.

Nick Strausfeld

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Nick Strausfeld

Illustration of what the Mollisonia animal would have seemed like on the time it lived, greater than 500 million years in the past.

Nick Strausfeld

Whether you like spiders or cannot be inside 10 ft of them, you most likely consider them crawling round on land. And primarily based on the fossil report, most researchers would most likely say the identical factor. For a very long time, they’ve thought the earliest arachnid ancestors existed round 450 million years in the past, residing and diversifying solely on land.

But a brand new study out this week within the journal Current Biology suggests their brains might have originated a lot earlier, within the ocean.

The researchers re-examined a fossil from a now-extinct marine arthropod referred to as Mollisonia symmetrica. It’s thought to have existed throughout the Cambrian interval, round 500 million years in the past, when all animal life was nonetheless within the ocean.

When examine creator and neurophysiologist Nicholas Strausfeld checked out this Mollisonia fossil, he says it appeared to have an identical mind group to arachnids — which embrace spiders and scorpions.

Strausfeld says whereas many Cambrian fossils, together with the ancestors of present-day crustaceans, have a “front-to-back” association, he and his co-authors noticed the reverse in Mollisonia.

“The arachnid is the only group in which this linear brain has been flipped back,” he says.

He says this group suggests excessive velocity and sophisticated leg actions, for issues like chasing prey or weaving webs.

One evolutionary biologist who didn’t work on the examine, Alejandro Izquierdo Lopez, mentioned in an electronic mail that this Mollisonia fossil is phenomenal and that the findings may very well be thrilling for the sphere. But he additionally famous that inspecting brains and nervous system tissue in fossils is a fancy course of.

It will take extra analysis to doubtlessly affirm the concept Mollisonia is, in truth, the earliest arachnid ancestor and that arachnids originated within the ocean.

Want to listen to extra tales in regards to the historical past of animals on Earth? Email us and tell us at [email protected].

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This episode was produced by Rachel Carlson and Jordan-Marie Smith. It was edited by Rebecca Ramirez, Christopher Intagliata and William Troop. Tyler Jones checked the information. Tiffany Vera-Castro and Robert Rodriguez have been the audio engineers.