Chromodoris daphne? from Papua New Guinea

Dear Mary Jane,
This is an interesting find. I think it is Chromodoris preciosa. Chromodoris daphne seems to be restricted to south-eastern Australia, although Marshall & Willan (1999) record it from the southernmost end of the Great Barrier Reef. It does not have a white or clear band at the sdge of the mantle and no white edging to the gills or rhinophores. In your photos there is some trace of a whitish mantle border outside the red, and white edging to the gills and rhinophores. I have not seen distinct red spots, as in your photo, in Chromodoris preciosa but the mottled animal certainly is characteristic of that species.

It also has similarities to Chromodoris trimarginata but in that species the gills and rhinophores are white or colourless. Alternatively we have to begin thinking that some of these species are just colour forms of each other, but as I commented recently about Glossodoris cincta, sometimes, when internal anatomy doesn't help with clearcut differences, it is difficult to decide where one species ends and another begins.

Photos like yours, although they complicate the picture, are extremely welcome because what we really want is the actual picture, not the easy answer.

Best wishes,
Bill