Nudibranche Doris DalmatienDiscodoris atromaculata
Discodoris atromaculata est un grand doridien qui peut atteindre 12 cm de long.
Son corp est ovale, son manteau coriace au toucher est blanc parsemé de nombreuses grandes et petites taches brunes qui rappellent la robe des dalmatiens. Ses rhinophores et ses huit branchies sont rétractiles. Souvent en groupe de deux ou trois individus, c'est un nudibranche que l'on rencontrera depuis la surface, sur les roches, ou, plus souvent, sur l'éponge Petrosia ficiformis dont il se nourrit.
Le doris dalmatien vit en Méditerranée et en Atlantique proche de la Méditerranée, au nord, jusqu'à la côte Basque.
Nudibranch PlatydorisPlatydoris argo ?
Not yet identified. Rare.
Calvi, Corsica 1998.
I have been quite puzzled by this photo as well. Its size, colour and very raised gill and rhinophore pockets are just as in Platydoris argo. Unless I am very wrong this animal has had most of the mantle skirt removed. I don't know if this species is known to autotomise its mantle when alarmed, but that could be one means of mantle loss - another could have been the persistent nibbling of a crab or fish. Any other ideas would be welcome.
I am pretty sure this is Flabellina ischitana. Another species which is of similar colour and has the cerata arranged on a common stalk like this is F. affinis. However in that species there is an opaque purple band around the cerata, just below the white tip, which can't be seen in this photo.
This is the largest chromodorid from the Mediterranean Sea and is widely distributed on both sides of the Atlantic. It varies greatly in colour and pattern and consequently has been known under many names including
Hypselodoris elegans (Cantraine, 1835), Hypselodoris webbi (d'Orbigny, 1839), Hypselodoris valenciennesi (Cantraine, 1841),
Hypselodoris edenticulata (White, 1952), Hypselodoris tema Edmunds, 1981.
This species differ in having an opaque purple band just below the ceratal tip. You can see it clearly in your photo, which would make it Flabellina affinis. The ceratal groups in your photo don't seem to be on such obvious basal stalks but I suspect they are very contracted in this photo.
In this photo you can also see the fine rings on the rhinophores. They are also present in F. ischitana but are not so clearly seen in your earlier photo. The two white sausage-shaped structures behind the first ceratal clusters are in fact the egg sacs of a parasitic crustacea living in the body cavity of the aeolid. Bill Rudman Australian Museum, Sydney.