Crustaceans from Mabul

Two crustaceans from Mabul that I can´t put a name on. Hopefully someone can. Also I would really like to know what the appendages are for on the first one. Both shot at night dives, both in about 15 m of water, the one with the appendages about 4 cm in total and the climber somewhat smaller.

Thanks

Bent C.

#1 Naxioides taurus, Bull crab

#2 Achaeus spinosus?

Cheers

Michael

#1 Naxioides taurus, Bull crab

#2 Achaeus spinosus?

Cheers

Michael

Thanks Michael! Do you have any idea what the exorbitant appendages are used for for the Bull crab?

/Bent C

Do you have any idea what the exorbitant appendages are used for for the Bull crab?

I think they use it for camouflage.

Cheers

Michael

There are other possibilities of decorator crabs with 2 prolonged spines on the front of the rostrum and only a few of them are in the popular guide books. Hyastenus bispinosus has them & is know to selectively attach hydroids (like Bent's critter) to itself. Naxioides has several species so even if it's in this genus it may not be taurus. The hydroids do break up the outline of the animal which makes it harder to see, especially when the animal is living on or near the same type of hydroid. I suspect that they are also used for defense as the hydroid's stinging cells will make attacking the crab an unpleasant experience.

Same caveat for the second crab. There are a lot of these stick crabs in many genera and again, only a few are in the guide books. The identification is very inconsistent for most of them so you see the same animals under a variety of different names.

Thanks Leslie. Then I´ll just leave it at decorator crabs.

Regards

Bent C