Chromodoris geminus? from South Africa

Dear Valda,
This looks quite like Chromodoris geminus which I described from Tanzania in 1987. Terry Gosliner has also reported C. geminus from South Africa (Chromodoris sp. 3. in his book), but I am not at all sure that your animal is the same.

It's a little bit deeper in colour than the C. geminus and differs in having the purple right at the mantle edge rather than submarginally. There is also a distinct deep yellow submarginal band in C. geminus while in your South African animals the yellow-brown background colour on the mantle is uniform. Also in C. geminus there are spots on the foot and a white edge, while in your animal I can't see if there are any spots on the foot but it has a purple edge. The rhinophore clubs in your animal are purple not yellowish. All in all I think this may be a mimic of C. geminus.

A very distinctive behavioural chracteristic of C. geminus which you can see in the photo at the top of the page is that the mantle edge is raised and lowered in one movement all around the mantle edge. Does your animal do that? C. kuniei from the western Pacific also flaps its mantle like this.

Your photos are very useful. The more photos we can get of species throughout their geographic range, the more chance we have of understanding the limits of a species' geographic distribution and colour variation. If you have photos which show the foot and mantle edge more clearly they could be useful.

Best wishes,
Bill Rudman.