Aglaja depicta from the Mediterranean

Dear Erwin & Gianni,
Thanks for these photos of 'Philinopsis' depicta which show the shape and colour variation so well. I had always thought, from written descriptions, that this species was very similar in colour to the Indo-West Pacific species Philinopsis cyanea and these photos certainly support that idea.

I was interested in seeing you placing this species in the genus Philinopsis rather than Aglaja. Many years ago I reviewed the family Aglajidae (Rudman, 1974) and sorted out a number of anatomical characters to separate the various genera in the family. Terry Gosliner (1980) added to this work, and suggested some modifications most of which I agree with. One point I have had difficulty in accepting is the move of Aglaja depicta to the genus Philinopsis. many internal and external features of the two genera are very similar but one very unique feature of species of Aglaja is the exogenous sperm sac opening directly into the spermoviduct rather than into the genital vestibule. Aglaja depicta has this character, and in the absence of any other convincing evidence I feel it should remain in that genus, rather than be considered an aberrant member of the genus . It may be that the distinction between Philinopsis and Aglaja is artificial, but showing that would need a lot more anatomical work to be done on all the species we know little or nothing about. At the moment species of Aglaja appear to be restricted to the Atlantic (incl. Mediterranean, Caribbean) and
species of Philinopsis to the Indo-West Pacific.

• Gosliner, T.M. (1980) Systematics and phylogeny of the Aglajidae (Opisthobranchia: Mollusca). Zoological Journal of the Linnean Society, 68(4): 325-360.
• Rudman, W.B. (1974) A comparison of Chelidonura, Navanax and Aglaja with other genera of the Aglajidae (Opisthobranchia, Gastropoda). Zoological Journal of the Linnean Society, 54(3): 185-212.

Best wishes,
Bill Rudman