Sea spiders can regrow body parts after amputation, study shows

A new study has shown sea spiders have the unique ability to regrow certain body parts, including not just limbs, after amputation.

Researchers now plan to explore the mechanisms behind the regrowth in an attempt to possibly one day regenerate limbs for millions of human amputees.

Senior author of the study, Gerhard Scholtz of Humboldt University in Berlin, said that “nobody expected this”.

“We were the first to show that this is possible,” he added of the research published in the journal Proceedings of the National Academy of Sciences.

Twenty-three immature and adult sea spiders had various hind limbs and posterior parts amputated and then analysed.

Among the adult sea spiders, no regeneration was found. However, many of them were still alive even two years after the amputation.

The immature sea spiders, on the other hand, experienced a complete or near-complete regeneration of their missing body parts, with 90 per cent surviving long term.

About 14 of the juvenile spiders experienced regrowth of their rear end, while none of the adult specimens molted or regenerated.

It is well documented that many different types of arthropods, (invertebrate animals with an exoskeleton, a segmented body, and paired jointed appendages) including spiders, salamanders, crabs, starfish, newts, lizards and centipedes, are able to regrow limbs after a loss.

“Crabs can even automatically get rid of their limbs if they are attacked,” Mr Scholtz said. “They replace it by a new limb.”

Researchers in the US recently triggered the regrowth of an amputated leg in a type of African clawed frog. They said this was one “step closer to the goal of regenerative medicine”.

Mr Scholtz said the findings could pave the way for further research in the field.

“There’s a wealth of different species that can be tested in this way,” he said.

“We can try to find out on the cellular level and the molecular level what indicates the regeneration.”