A spider crab that disappears under its own decoration. The shell and legs are covered in hooked setae, and the animal attaches sponge, hydroid and algal fragments to them until nothing of the crab shows - what moves across the rubble is a walking piece of the reef with long thin legs underneath. The body reaches about 4 cm (1.6 in).
The decoration is deliberate and maintained: a crab moved to a different substrate strips its old covering and re-dresses to match within a day or two. Pieces are trimmed to size with the claws before being pressed onto the hooks. It feeds at night on detritus and small animals, and by day sits motionless in a crevice, indistinguishable from its surroundings. Divers usually find one by noticing that a lump of sponge is in the wrong place, and then that it has stopped moving because it noticed them first.
- body and legs completely covered in attached sponge and algae
- very long thin legs, the animal itself barely visible
- moves slowly and stops dead when watched
- body up to 4 cm across
