Unknown Critter - Mabul Malaysia

[Rickg]

My wife and I were recently (DEC 07) on a diving trip to Malaysia. While on one of our dives off of Mabul Island I took several pictures of something that I have no idea of what it is. It looks like a crab of some sort but doesn't appear to have a hard shell. None of the dive guides were able to give me any help in identifying this critter.

The picture was taken between 5-7m water depth off of Mabul Island in the vicinity of what is referred to as the the Jetty/House Reef.

Any assistance you can provide would be greatly appreciated because I have never seen anything like this before.

Rickg

 

[dlscozz]

Sorry I can’t help you but it is a cool picture. How wide is it?

 

[LeslieH]

It's a decorator crab probably in the family Majidae. Looks like it's covered with a sponge which produces the soft appearance. If you do a google search on Achaeus and Oncinopus you'll find images of similar crabs.

 

[Rickg]

Sorry I can’t help you but it is a cool picture. How wide is it?

dlscozz,

Not very large, maybe about 1 - 1.5 inch across.

Rickg

 

[Rickg]

It's a decorator crab probably in the family Majidae. Looks like it's covered with a sponge which produces the soft appearance. If you do a google search on Achaeus and Oncinopus you'll find images of similar crabs.

Leslie,

Thanks for the info. We did see lots of other decorator crabs in that area but nothing that looked quite so "flesh-like" with such a smooth appearance over the entire crab.

I spent some time on Google and will do some more searching tomorrow.

Rickg

 

[LeslieH]

Here's some majids covered with sponges or ascidians for that soft look -

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Poppe Images - Marine Iconography in the Philippines
http://www.manleylabs.com/galleria/DIVING/indonesia_dive_manado.html
Diving The Gold Coast

 

[Rickg]

Here's some majids covered with sponges or ascidians for that soft look -

ƒAƒPƒEƒX
Poppe Images - Marine Iconography in the Philippines
http://www.manleylabs.com/galleria/DIVING/indonesia_dive_manado.html
Diving The Gold Coast

Leslie,

Here are some of the other decorator crabs we saw around Mabul.

And here is one of my favorites from when we were diving in the Lembeh Strait. He was pretty easy to see at night carrying around that fire urchin.

 

[LeslieH]

I think decorators are the funniest crabs. Mark Thorpe (CamDiver) has a great video clip of one (maybe the same species as your #5 & 6) that deserves the name trash crab. it had cigarette butts, chewed betal nut waste, and other debris attached to it's body.

Did you want names for your crabs?
1 & 3 are Cyclocoeloma tuberculata. It almost always has corallimorph anemones for decoration and the legs are banded black & white. It's easy to id
2,5,6 - may all be Camposcia retusa. The way it uses clumps of material which produce a beaded look on the long legs is pretty typical.
7 - might also be Camposcia with the sponges/tunicates fusing together for a smoother look. There are many long-legged decorator species however and it's hard to tell them apart without ripping off the covering.
4 is probably a dromidae. The last pair of legs on these crabs are reduced in size & point up over the back so they can hang onto the hollowed out sponges they use for camouflage
8 belongs to another family of carrier crabs, the Dorippidae. Dorippe & Ethusa seem to be the 2 most common genera in the Lembeh area. This family has 2 pairs of rear legs are reduced in size & point upwards. They prefer urchins & cnidarians whereas dromids use sponges.

Odontozona is a crustacean expert. Hopefully he'll stop by and provide better identifications.

 

[Rickg]

Leslie,

Thank you providing the names. Names are definitely my weak point when it comes to my picture taking.

 

[Polpessa]

Wonderful photos of these fascinating creatures. The one with the urchin is awesome...