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New Species Discovery! A Hermit Crab Carrying Coral on its Back


We all know that hermit crabs (little crustaceans that somewhat resemble a squid with claws) love to carry around their “portable home”. But will you find it weird if they actually carried a living life form like an oversized backpack?

First off, we have to discuss this coral. This free-living coral (meaning it's unattached) is sometimes inhabited by marine worms that seek protection from predators. They, in turn, help the coral get around and not be buried under sediment. Well, guess what, some curious crab got creative and buried itself in the coral instead of some of those poor marine-worms that just wanted a life. Interestingly enough, the newly discovered crab species, Diogenes heteropsammicola, was identified purely by accident.

Momoko Igawa, co-author of the paper published in PLOS One (Public Library of Science), told CBC News that Makoto Kato (who is also a co-author), had collected a walking coral from a survey in Oshima Strait north of Kakeorma Island in the south of Japan in 2012.

'I was amazed at the mysterious animal.' - Momoko Igawa, co-author

"The coral had been fixed in 99 per cent ethanol, but we cracked the coral and observed internal corallum structure," Momoko said in an email. "As a result, we found that a very slender hermit crab was in the coral. Since then, we have been collecting walking corals in Oshima Strait every year in order to see the hermit crab alive."

This tiny hermit crab had unusually slim legs and possesses a symmetrical tail, unlike its cousins who have curled tips that fit nicely in their right-handed coiled shells that they call “home.” Scientists have also concluded that the coral grows alongside the crab, which allows it to permanently settle in the coral.

There you have it, biology freaks: All the honest information curled up nice and snug into a little article: just like the little crab and its living home. Farewell, until we meet again in time for the next species report!

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