Northeast coast of Nth America (Massachusetts, Maine), Greenland, Iceland, the Faeroes, Barents Sea, nthn coast of Norway. Reported below from Ireland.
New England. Photo: Paul Young
Grows to 40-50mm. Translucent white body with maroon to red-brown cerata with conspicuous white tips. The elongate body has numerous cerata evenly distributed and held tightly and flattened over the dorsum. There are a few scattered white specks behind the pericardium and these coaslesce to form a median white line down the length of the pointed 'tail'. The oral tentacles have a median line of white specks which grows thicker towards the tip and the rhinophores have white pigment spots at the tip, especially on the posterior edge. The rhinophores appear somewhat wrinkled but on close examination are seen to be covered in small papillae or warts.
Five species of of Flabellina have been recorded from the east coast of North America and while they are quite distinguishable on the shape of their radular teeth it is sometimes difficult to identify them externally, in the field or from photographs. The species are Flabellina verrucosa, Flabellina gracilis, Flabellina pellucida, Flabellina salmonacea & Flabellina nobilis. If anyone could summarise the differences between these species, so they could be identiifed more easily in the field, or from photographs, I would be grateful.
• Kuzirian, A.M. (1977) The rediscovery and biology of Coryphella nobilis Verrill, 1880 in New England (Gastropoda: Opisthobranchia). Journal of Molluscan Studies, 43: 230-240.
• Kuzirian, A.M. (1979) Taxonomy and biology of four New England coryphellid nudibranchs. Journal of Molluscan Studies, 45: 239-261.
Rudman, W.B., 2001 (June 28) Flabellina nobilis (Verrill, 1880). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/flabnobi
July 21, 2001
From: Bernard Picton
Here is an interesting record of Flabellina nobilis to add to the information accumuating in the Forum on Flabellina in the North Atlantic.
The previous southern limit was Norway and the Faeroe Islands. Here are photos of an
unpublished Irish record - a single juvenile specimen but I'm fairly positive about the identification. It is from Mulroy Bay, Co Donegal, Ireland. March 1980.
Picton, B., 2001 (Jul 21) Flabellina nobilis from Ireland. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4843
June 30, 2001
From: Bruce Wight
firstname.lastname@example.orgWight, B., 2001 (Jun 30) Re: Flabellina nobilis. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4700
As I am an expert on neither species please feel free to disagree with me if I say something silly.
I guess the smooth rhinophores in C. divae is one character and the continuation of the ceratal rows in front of the rhinophores are another point of difference. Another would be the rounded anterior foot corners in species of Cuthona which in species of Flabellina are usually tentacular. In colour, the rhinophores and oral tentacles of Cuthona divae are the same colour as the body with no white pigmentation on the skin, while in F. nobilis there is a row of white spots on both. F. nobilis grows much larger than C. divae. On top of these external features there are many anatomical differences, not visible in the field of course, which separates them.
Not withstanding all that, you are right, they certainly look similar in photographs.
June 29, 2001
From: Paul Young
Here is a better photo of the red-gilled nudibranch showing the rhinophores.
email@example.comYoung, P., 2001 (Jun 29) Better photo of New England Flabellina. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4676
Jussi Evertsen has alerted me to the interesting fact that this photo is of another species of Flabellina, F. nobilis. See his separate message. I have discussed the differences between the species of Flabellina known from the Nth American east coast at the top of the page.
June 29, 2001
From: Jussi Evertsen
Regarding Paul Young's last picture, this nudibranch is actually Flabellina nobilis Verrill, 1880 not Flabellina verrucosa. This can be seen by the continous arangement of cerata along the sides of the back, and if you examine the rhinophores, they are papillate.
firstname.lastname@example.orgEvertsen, J., 2001 (Jun 29) New England Flabellina is F. nobilis. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4689
June 29, 2001
From: Bill Rudman
Having just posted Jussi Evertsen's message on Flabellina nobilis I reakise it would be very useful if someone with a knowledge of these animals couldd provide us with a brief summary of the external characters we could use to identify the species of Flabellina from the North American east coast. I attempted to do it myself from Kuzirian's papers and Sherman Bleakney's book, but I think it requires some local knowledge. Any volunteers?
The species are Flabellina verrucosa, Flabellina gracilis, Flabellina pellucida, Flabellina salmonacea & Flabellina nobilis. If anyone could summarise the differences between these species, so they could be identiifed more easily in the field, or from photographs, I would be grateful.