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The “mushroom crabs” that wear a kind of oversized mushroom hats over their bodies fascinate scientists with their unusual appearance. In particular, these crustaceans would spend a lot of time making their headgear with strangely varied techniques, and biologists do not yet fully understand the behavioral relationships. A new species of the group, baptized Lamarckdromia beagle and recently discovered off the west coast of Australia, scientists amaze with its much more fluffy appearance than the others. The creature is indeed so hairy that it resembles an adorable living stuffed animal. If its congeners use their hats to camouflage themselves, scientists do not yet understand why this new species has chosen such an “eccentric” appearance.
The Dromiidae family, to which fungal crabs belong, has more than 130 species. Their behavior in the wild is unique among crustaceans as they all carry live fungi over their shells. These crabs shape their hats especially by cutting them with a kind of sharp claws placed on their hind legs.
These mushroom hats would be used for camouflage purposes or to fool predators, as mushrooms are generally poisonous and repel many fish. As for the fungi, we can not confirm whether they are interested in being transported, but biologists have been able to establish that they are not harmed when the crabs chop them. In addition, the latter probably have every interest in keeping them alive so that they can remain poisonous and thus repel predators.
that Lamarckdromia beagledescribed in the review Zootaxa, was named in honor of The Beagle, the boat that Charles Darwin traveled on during his expeditions. This new species would only be found between Albania and Cape Naturaliste, in shallow seas – no more than a few hundred meters. This hairy crab would also prefer to settle around harbor pillars where there are large populations of fungi.
According to Australian researchers, this family of crabs is known to be generally fluffy, but the Lamarckdromia beagle is so tattered that it is surprisingly soft. ” All members of this group of crabs are to some extent hairy, but this one is ridiculous said Andrew Hosie, co-author of the new crab study and crustacean expert at the Western Australian Museum. According to the expert, this species would have gradually “chosen” this appearance to further camouflage its legs, but this is only an unconfirmed hypothesis at the moment.
Many crabs are used to camouflage themselves with elements of their environment (sand, colored corals, etc.), but fungal crabs are intriguing with their elaborate camouflage despite a rather primitive nervous system compared to other families of the crustacean.
According to Western Australian researchers, they use their hind legs to support the trimmed hats over their bodies. Like real little artists, they shape the mushrooms so that they follow their shapes with astonishing precision, without harming them.
In addition, previous research has shown that these crabs can spend a lot of time making their hats. In particular, experiments with synthetic sponges have shown that they spend an average of 50 minutes cutting the foam to the right size and up to 5 hours digging the perfect hole in it to place their small bodies.
In addition, each crab is said to have its own cutting technique, suggesting that personality traits might affect the shape of hats – such as the uniqueness of the Lamarckdromia beagle.