Hermaea noto and H. zosterae

Dear Nishina,
Thanks for this information. Both Stiliger (Ercolania) noto and Stiliger (Ercolania) zosterae were described by Baba (1959) in the same paper. They both have auriculate rhinophores and have blade shaped radular teeth so would today be considered species of Hermaea.

'Stiliger (Ercolania) noto' was described as growing to 5-10mm and having auriculate rhinophores. In colour, the entire animal almost black. The head marked by having 4 longitudinal bands of black, and a white patch in the median part and round each of the eyes. The pericardial prominence whitish. Branchial papillae black, the inner and outer edges towards the the end white, their tips yellowish brown.

'Stiliger (Ercolania) zosterae' was described from a single 3mm long animal. It was also described as having auriculate rhinophores. In colour, the head had a reddish U shaped mark and an additionals longitudinal line on each side. In most features the description certainly fits the photos in the Forum photo 1 photo 2 of supposedly juvenile H. zosterae.

On looking at the descriptions and the photos we now have available, I tend to think that H. noto and H. zosterae are the same species, H. zosterae being the juvenile colour form. It seems that the U shape on the head breaks into a pair of lines as the animal grows and its colour deepens from purple-red to black. If they do turn out to be the same I suggest H. noto should have precedence over H. zosterae since it is based on a number of specimens and appears on the page before H. zosterae in Baba (1959).

• Baba, K. (1959) The family Stiligeridae from Japan (Opisthobranchia-Sacoglossa). Publications of the Seto marine Biological Laboratory, 7(3): 327-336.

Any comments are very welcome.
Best wishes,
Bill Rudman