March 20, 2001
From: Bernard Picton
I see there is a suggestion that this animal may be Cuthona gymnota. I'm certain that it is not, in fact I'm sure it is none of the Cuthona's I've ever seen in the Northeast Atlantic. It has the proportions of what I'd call a typical Cuthona (Trinchesia) like most of the species in this part of the world, eg. C. amoena or C. rubescens. I tend to think of the cerata as cigarette-shaped rather than cigar-shaped and the rhinophores and oral tentacles are relatively long and gently tapering. In C. gymnota the rhinophores and oral tentacles don't have white surface pigment and are colourless or tinged with orange. The rhinophore and oral tentacle pigmentation in these species is usually a reliable character in my experience. If Juan Lucas doesn't know it from the Mediterranean then it is probably a new species as he says in his earlier message.
I still use Catriona for this species as it seems different to the other
British species of Cuthona in a number of ways and has a distinctive radula. I've sent two pictures of Cuthona gymnota in a separate message.
firstname.lastname@example.orgPicton, B.E., 2001 (Mar 20) Re: Cuthona sp. 5. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3997