Re: Cuthona granosa ? from the Mediterranean

January 9, 2002
From: Bernard Picton

Hi Bill,
Jean-Pierre Bielecki's aeolid is believed to be a colour form of Aeolidiella alderi. I have seen it myself in Mulroy Bay, Co. Donegal, Ireland and it was found by Lemche in Co. Galway (see Just. H. & M. Edmunds, 1985. North Atlantic Nudibranchs (Mollusca) seen by Henning Lemche. p138-140). It differs from typical A. alderi in having bright orange rhinophores and some orange pigment on the cerata, but Tardy reported that there was considerable variation in the colour of this species and the orange may be derived from the diet (sea anemones). Julia Nunn, (who works here in the Ulster Museum) has also found this colour form in Mulroy Bay and reviews all records of the species in Ireland in a paper in Irish Naturalists Journal (Nunn, 1993). Julia has since seen the orange form again at Inishbofin Island, Co. Galway. It is predominantly a shore species, feeding on sea anemones beneath loose rocks.

The orange form seems only to have been reported from Ireland so it is interesting to see the exact same colour form from the Mediterranean. I've attached Julia's photo of one of the three orange specimens from Mulroy Bay, 10mm in length.

• Nunn, J., 1993. Aeolidiella alderi (Cocks, 1852) (Mollusca: Opisthobranchia) in Ireland. Irish
Naturalists Journal, 25(6)
: 258-260 and colour plate)


Picton, B.E., 2002 (Jan 9) Re: Cuthona granosa ? from the Mediterranean. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from

Thanks Bernard,
An interesting record.
Bill Rudman


Aeolidiella alderi

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