A small hydroid-feeding aeolid from a genus that needs a sharp photograph to name.
A small aeolid, seldom more than 2 cm, the body translucent white with the cerata carrying an orange to red-brown digestive gland along the core and an opaque white tip, and with orange banding on the rhinophores and oral tentacles. The cerata are arranged in distinct rows down each side rather than in scattered clusters. It is worth being plain about the limits here: Trinchesia holds many small and similar species in this region, several of them still undescribed, and the differences run to the exact colour of the ceratal core and the banding on the rhinophores. Those are separations that need a sharp lateral photograph and are not reliably made in the water.
The species was long placed in Cuthona, and most guidebooks still give it as Cuthona sibogae. The name change is a generic rearrangement rather than a redescription of the animal.
Feeds on hydroids and, in common with the aeolids generally, stores the prey’s undischarged stinging cells in sacs at the tips of the cerata. At 2 cm on a hydroid colony it is found by working along the hydroids rather than by spotting it crossing open ground, and it is a serious magnification subject — most frames that resolve the ceratal detail are taken with a dioptre. Recorded from about 3 to 25 m on rubble, wreckage and jetty structure.
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.
