Pilumnus vespertilio  

Carapace hexagonal, densely setosed with a few regions defined, frontal region with quadrilobed with prominent medial notch. Anterolateral margin with three teeth. Chelipeds nearly equal in size. Male abdomen somites 3-5 are moveable.

Vernacular name: Hairy crab.

The long setae of this crab traps dirt and mud, which helps it to maintain an effective camouflage in reefs. In addition, there have been reports that they are slightly poisonous.