Sea spider or stick?

The dive guide pointed this out to me on a dive in the Wakatobi area. It's fairly big at about 3 or 4 inches across. I looked at it for a while before I saw it appeared to be one animal. I thought it was a pile of sticks until I counted 8 legs and saw it move.

New one on me,

Steve

Definitely a Sea Spider. We see them here fairly regularly in Lembeh. Weird things, not spiders, not crabs, but their own 'thing'

Wiki Sea Spider Info

Yours has lots of nice growth, but we also get them a little smoother than that..

My guess is some species of stick crab like Chalaroachaeus curvipes -

http://wetpixel.com/forums/index.php?showtopic=37345

http://wikitivity.jp/scuba-diving/modules/...%82%A6%E3%82%B9

The two legs with claws by the mouth are short & used for manipulation rather than walking. In Steve's pic the two legs are sort of dead center.

Liquidguru's got an outstanding video on his http://divekbr.com/blog/?cat=4 which shows a related crab - the skinny sponge crab (Oncinopus or Achaeus depending on which reference you check) right after molting. It's using the two short arms to pick pieces of sponge away from the discarded carapace & transfer them to it's new carapace. This is typical behavior for decorator crabs & other crustaceans. Even the big hermits that carry anemones on their shells will move the anemones from an old shell to a new one.

Steve - Reminds me of a sea spider. Saw one in Little Cayman. Very hard to find since they tend to blend into their surroundings most of the timeand are so small.

Pam