Separated from the common blue phyllidiids on characters a photograph rarely shows.
A phyllidiid to about 5 cm built like the rest of the family and belonging to the blue-grey group — a firm notum with black longitudinal markings, rows of low tubercles tipped yellow, yellow rhinophores, and no gill plume. It was distinguished from its relatives in the 1993 revision of the Indo-West Pacific phyllidiids, on the arrangement of the tubercles and on the pattern of black on the underside of the mantle. Neither character is available in an ordinary photograph of a crawling animal, and the honest position is that this species and Phyllidia coelestis are not reliably separated in the water. A proportion of what is recorded as coelestis on these sites is likely to be this.
Like the whole family it feeds on sponges and holds their compounds in the skin, which is why it moves about in the open by day. Spawn is a pale ribbon coiled on or beside the food sponge. Nothing specific is known about which sponge it takes here.
The depth and habitat given here follow the family rather than the species.
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.
