A brittle star with five slender, unbranched arms banded in black and white along their length - the pattern behind the name pica, Latin for magpie. The central disc is small and granular, rarely more than 2 cm across, while the arms reach about 10 cm (4 in), so almost the whole animal is limb. Arms move in fast serpentine sweeps, nothing like the slow tube-foot creep of a sea star.
By day it stays hidden under coral rubble, slabs and rocks on shallow reef, down to about 20 m (65 ft), often with just one or two arm tips protruding to sample the water. At night the animal emerges to feed, sweeping detritus, organic particles and small prey towards the mouth on the underside of the disc. Arms break off readily when seized - the defense the whole group is named for - and regrow from the stump over following weeks, so animals with arms of visibly different lengths are common. The species was long lumped into Ophiocoma and only recently moved to Breviturma, so 🌊 Red Sea guides printed before the change list it under the older genus.
- arms banded black and white along their length
- small central disc, five long unbranched arms
- hides under rubble by day, arms out at night
