A cryptic sponge-feeding dorid under a coat of silt, with a ridge along the middle of the back.
A firm dorid to about 5 cm, the back covered in low conical tubercles and carrying a raised ridge running down the midline from between the rhinophores to the gill. Colour is grey, fawn or brown, and the surface holds a layer of settled sediment, so the outline disappears into silty rubble almost completely. The mantle is wider than the foot and the margin is often irregular.
The gill and the rhinophores retract into pockets, and a disturbed animal flattens and stops moving, at which point there is very little left to see. Most records begin as a shape that turned out to be moving: the animal is more often noticed by the clean trail it leaves through settled silt than by anything about the animal itself.
The genus feeds on sponges. It occurs on the same silty rubble ground as the phyllidiids but is soft-textured rather than rubbery, carries a proper retractile gill plume at the back, and never shows their pattern of black lines and coloured tubercles. Species are separated on the tubercles and the ridge and are not reliably split from a photograph. Recorded from about 3 to 30 m.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.
