Flabellina verrucosa
(M. Sars, 1829)
Order: NUDIBRANCHIA
Suborder: AEOLIDINA
Family: Flabellinidae
DISTRIBUTION
Boreo-arctic from southern New England, USA in the west Atlantic to the British Isles in Europe. Also in north Pacific to the Sea of Japan.
PHOTO
UPPER: 25mm long, off Long Island, New York, USA., approx 4 meters. LOWER: Brown colour form, 25mm long, off York Beach, Maine, USA, on an old pier at about 20 feet (7 meters). PHOTOS: Betsey Hansen.
This species has a confused taxonomic history with different colour forms and animals from Europe and North America, being considered different species. It is also very similar in appearance to Flabellina gracilis. It grows to about 25mm long. It feeds on a number of thecate and athecate hydroids, and if food is short has been reported to feed on the compound ascidian Botryllus schlosseri. Kuzirian (1979) did much to sort out the confusion amongst North American names. See original plate from Sars, and discussion on whether forms with long cerata and forms with short cerata are a single species.
Comparison from Terry Gosliner message below: 'The main external characteristics for differentiating F. verrucosa from Flabellina gracilis is that the cerata are more distinctly arranged in rows in F. gracilis and there is a more prominent vestige of a notal brim in F. gracilis. Also F. gracilis has a sort of notched head between the junction of the oral tentacles and more elongate anterior margins of the foot'.
Reference:
• Kuzirian, A.M. (1979) Taxonomy and biology of four New England coryphellid nudibranchs. Journal of Molluscan Studies, 45: 239-261.
• Sars, Michael. 1829. Bidrag til soedyrene naturhistorie, Pt. 1,: pp. 1-59, pls. 1-6. Bergen.
• Thompson, T.E. & Brown, G.H. (1984) Biology of Opisthobranch Molluscs, Vol 2. Ray Society: London.
Related messages
Re: Flabellina verrucosa from British Columbia
November 5, 2007
From: Jackie Hildering & Glen Miller
Concerning message #11287:
More feeding Flabellina verrucosa. This time chomping down on the giant pink-mouth hydroid, Tubularia indivisa. One specimen about to feed. The other image shows a specimen having completed its grazing on this hydroid.
Locality: North East Pearse, 45 feet, British Columbia, Canada, Pacific Ocean, 20 October 2007, Wall. Length: 7 cm . Photographer: Jackie Hildering.
Jackie Hildering and Glen Miller
earthlingenterprises@telus.net
Hi Jackie and Glen,
Great documention of the feeding of this species.
Thanks for sharing,
Dave Behrens
Flabellina verrucosa in West Puget Sound
September 15, 2007
From: Dave Washburn
I'm reasonably sure these are Flabellina verrucosa, but would appreciate confirmation. They are fairly profuse at Harper's Ferry, a popular dive site on the west side of Puget Sound near Port Orchard. Most are an inch long at most, so getting a good macro photo is a good challenge. The photos are of two different ones that we found on successive dives at this site.
Locality: Harper's Ferry, 20 feet, Washington, USA, Puget Sound, 05 September 2007, Old auto ferry dock, gravel and lots of seaweed. Length: 1 inch. Photographer: Dave Washburn.
Dave Washburn
dwashbur@nyx.net
Washburn, D.L., 2007 (Sep 15) Flabellina verrucosa in West Puget Sound. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20690
Dear Dave,
The relatively short spindle-shaped cerata, and their arrangement into 'clumps' seems to be characteristic of Flabellina verrucosa.
Best wishes,
Bill Rudman
Flabellina verrucosa from Massachusetts
August 18, 2007
From: Charlotte Richardson
Hi, Bill -
Locally we call these the chocolate variety of the red-gill (Flabellina pellucida and related species). Paul Young and I found this one on the wreck of the Chester Poling, at the entrance to Gloucester Harbor (Massachusetts) on July 29th, at a depth of about 85 feet. These animals look like what locals call red-gills, but they tend to be larger (this one a bit more than 3 cm long), and, as you can see, the cerata are brown instead of red, and very numerous. The wreck is heavily overgrown with pink-hearted
hydroid colonies, which may be this nudibranch's food (it is for the usually red-gills - they are usually seen on the hydroid colonies, and lay their egg ribbons on them). Interestingly, this wreck used to have far more metridium anemones and far fewer hydroids than it does now, perhaps a sign of warmer water temperatures. At sites south of Cape Cod where the hydroids used to be very common twenty years ago, they are rare now, and so are the red-gills which used to be quite numerous there.
Locality: Gloucester Harbor, 85', Massachusetts, Atlantic Ocean, 29 July 2007, wreck on sand bottom. Length: 3-4 cm. Photographer: Charlotte Richardson.
Charlotte Richardson.
clr@underwater.org
Richardson, C., 2007 (Aug 18) Flabellina verrucosa from Massachusetts. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20468Dear Charlotte,
Unfortunately colour of the digestive gland duct in the cerata is not always a useful character because it can change depending on the colour of their most recent meal. I am pretty sure this animal is Flabellina verrucosa rather than F. pellucida. However it doesn't have a clear white line down the rhinophores and oral tentacles, and I can't see if it has a white line down the dorsal midline of the 'tail', so I could be wrong. Hopefully an Atlantic expert can put us straight.
Best wishes,
Bill Rudman
Flabellina verrucosa egg masses
March 26, 2007
From: Jackie Hildering
Hello Bill,
Of this one we can be fairly certain - Flabellina verrucosa and its eggs on the well grazed bushy pink-mouthed hydroids (Ectopleura crocea).
Locality: Marg's Wall (Plumper Island Group), 37', British Columbia, Canada, Pacific Ocean, 18 March 2007, Wall. Length: 1.5 cm. Photographer: Jackie Hildering.
Jackie
earthlingenterprises@telus.net
Hi Guys,
Great observation. We need more of these. Although the egg masses of many species of aeolids are known and well documented, many are not. Your shots here show an interesting morphology to this species' egg mass. This loosely tangled chain of egg capsules is quite characteristic.
Thanks so much,
Dave Behrens
Flabellina verrucosa - odd food choice?
April 18, 2005
From: Alan Shepard
Dear Bill -
Greetings from New England! I had a very successful dive the other day at Folly Cove in Gloucester, Massachusetts, USA. In a rather short period of time I encountered nine different nudibranch species in the chilly (5C) water.
One individual I found particularly interesting. This Flabellina verrucosa, the most common nudibranch in the cove, was feeding on what appeared to be some type of amphipod. Being so small it was hard to tell while underwater and I took the enclosed photo just to be sure. I fairly certain it is indeed feeding on an amphipod. McDonald and Nybakken's site does not seem to list amphipods on F. verrucosa 's diet but I'm no expert on scientific names and could have missed something. Do you agree that it is feeding on an amphipod? If so do you think it actually caught an amphipod or did it scavenge an already dead amphipod?
Locality: Folly Cove, Gloucester, Massachusetts, USA. Atlantic Ocean.
Depth: 7 meters. Length: 16 mm. 9 April 2005. boulder covered shoreline. Photographer: Alan Shepard
There's always something new to find in the world of Northwest Atlantic nudibranchs.
Best wishes,
Alan Shepard
Tolland, CT, USA
alan.chepard@snet.net
Shephard, A.D., 2005 (Apr 18) Flabellina verrucosa - odd food choice?. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/13512Dear Alan,
It certainly looks like a crustacean of some sort. Certainly some glaucids, such as a Austraeolis ornata and Hermissenda crassicornis are known to eat the odd bit of carrion, but I haven't heard of species of Flabellina doing this. It certainly seems an interesting observations for someone to follow up.
Best wishes,
Bill Rudman
Flabellina verrucosa from British Columbia
October 24, 2003
From: Bruce Wight
Dear Bill
Here are some photos of Flabellina verrucosa from our recent trip to British Columbia.
Johanna and I were up at the Northern end of Vancouver Island the first week of October diving around Port Hardy and Browning Pass, British Columbia. This was our first time diving in Canada.
The Flabellina verrucosa were very abundant and were found feeding on Tubularia up in the shallower water less than 40 feet deep.
Take care,
Bruce Wight
bwproductions@earthlink.net
Wight, B., 2003 (Oct 24) Flabellina verrucosa from British Columbia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/11287
Thanks Bruce,
They ceratinly have done a good job on the Tubularia. I think the two polyps in the top photo are the only two stalks left with a polyp intact. I knew the tail of this species was quite long, but your photo shows just how far it can extend
Best wishes
Bill Rudman
Flabellina verrucosa from British Columbia
July 2, 2003
From: Marli Wakeling
Hi Bill,
Here are some Flabellina verrucosa from the Broughton Archipelago. They are eating Tubularia crocea. These are the 'long cerata' type.
Location: Broughton Archipelago, British Columbia, Canada. Depth: 45 feet., Length: 10-12mm., May 2003. Photos: Marli Wakeling
Marli Wakeling
scubamarli@excite.com
Wakeling, M., 2003 (Jul 2) Flabellina verrucosa from British Columbia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10088
Thanks Marli,
Your photos clearly show their love for tubularian hydroids, although it has been reported to feed on quite a variety of hydroids
Best wishes,
Bill Rudman
Flabellina verrucosa from British Colunbia
June 27, 2003
From: Marli Wakeling
Hi Bill,
Further to your discussion on long and short cerata on Flabellina verrucosa:
I had never seen the short variety, when shortly thereafter found a small one whilst diving in Howe Sound near Vancouver, British Columbia. I have also never seen one in such an intense shade of crimson.
Location: Keats Island, Howe Sound, British Columbia.
Date: May 10, 2003
Depth: 40 feet
Length: 8mm
Photo: Marli Wakeling
Marli
scubamarli@excite.com
Wakeling, M., 2003 (Jun 27) Flabellina verrucosa from British Colunbia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/10090Thanks Marli,
Bill Rudman
Flabellina verrucosa with short cerata
May 13, 2003
From: Robert Eriksson
Dear Bill,
These photographs were taken in the Gullmarsfjord in Sweden, April 2003, at divesite Jordfall.
Concerning the correspondence about Flabellina verrucosa with short cerata. These photos show the short cerata, with clear gaps in between. I am puzzled by this appearence - is it really a Flabellina verrucosa? I am bound to think otherwise. In particular look at the white lines on the rhinopores, and the length of them.
I am a marine biology student at Gothenburg University. Just recently, I have launched a non-profit website with some photos on it. I thought you might be interested ...
http://dive.to/opisthobranchia
Thanks
Robert Eriksson
karlroberteriksson@hotmail.com
Eriksson, R., 2003 (May 13) Flabellina verrucosa with short cerata. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/9910Dear Robert,
Thanks for the photos. As I said earlier, the forms with short cerata and long cerata certainly look different to me, but the only way to be sure to compare their anatomy and biology. As to your suggestion that it 'doesn't look like F. verrucosa' - it seems the opposite is true. If you look at Sars's original description then you will see that your 'short cerata' form does look very like F. verrucosa. It's just that all the photos you will have seen are of the 'long cerata' form. If the two forms are different species, then it is the 'long cerata' form which is not F. verrucosa. Unfortunately it then gets complicated as there are many old names that have been given to specimens in this 'F. verrucosa' group. Flabellina rufibranchialis (Johnson, 1832) is possibly the first available name for the 'long cerata' form but that would need to be checked. This 'species' well illustrates how much we still need to learn about the marine fauna of even some of the most well studied faunas of the world.
Thanks for alerting me to your website. I will watch it grow with interest.
Best wishes,
Bill Rudman
Re: Flabellina? from Norway
April 30, 2003
From: Jussi Evertsen
Dear Bill,
In response to Kåre's recent message, here is a scan of the original illustrations by M. Sars (1829) of Eolidia verrucosa [Plate 2, figs 1-4].
You will see that Kåre's photos very much match the original descriptions of Flabellina verrucosa; except the arrangement of the cerata which more resembles Odhner's Flabellina borealis. But Kåre's photos are Flabellina verrucosa with short cerata. The problem is that Flabellina verrucosa has a long list of synonyms, which include individuals with long and slender cerata, and in most cases it is the animals with long cerata that are illustrated on the net (as in Coryphella rufibranchialis).
Also one should be aware of Bernard Picton's Flabellina browni, which really is similar to Flabellina verrucosa with long and slender cerata, but which is differentiated on the coloration.
Confusing? It really is, and I think this group is in need of a careful revision.
• Sars, Michael. 1829. Bidrag til soedyrene naturhistorie, Pt. 1,: pp. 1-59, pls. 1-6. Bergen.
Jussi Evertsen
jussi.evertsen@vm.ntnu.no
Thanks Jussi,
I am glad to see I am not the only one confused. Certainly Kåre's photos look like Sar's illustration of Flabellina verrucosa. Alan Kuzirian (1979) has an interesting review of the long-running dispute over the question of whether Eolidia verrucosa Sars, 1829, with short crowded cerata, and Eolis rufibranchialis Johnson, 1832, with longer fewer cerata, are synonyms or not. On top of this basic question are all the later names that have been given to this species or pair of species on both sides of the Nth Atlantic. I agree that step 1 must be for someone to study the anatomy and natural history of these two 'forms' in depth, as Kuzirian did with the Nth American Atlantic species of Flabellina.
One anatomical point which seems worth following up is the shape of the anterior foot corners. In both Sars' painting and Kåre's photo the anterior corners of the foot are rounded. Although none of the photos in the Forum of the long cerata form show the anterior foot clearly, there are plenty of illustrations in the literature showing that it has distinctly angular or even tentacular foot corners [Thompson & Brown, 1984]. To me the ceratal shape and arrangement and the anterior foot corners are pretty good arguments for some separating them.
• Kuzirian, A.M. (1979) Taxonomy and biology of four New England coryphellid nudibranchs. Journal of Molluscan Studies, 45: 239-261.
Best wishes,
Bill Rudman
Re: Flabellina? from Norway
April 30, 2003
From: Kåre Telnes
Thanks for responding to my message so promtly. I am sorry, I do not have any pictures showing the front of the foot clearly. The best I can do is the images attached. I hope they are to any help.
Regards
Kåre Telnes
kaare.telnes@online.no
Telnes, K., 2003 (Apr 30) Re: Flabellina? from Norway. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/9807
Thanks Kåre,
I've included you close-up of the cerata alongside as they show the shape of the cerata very well. From Jussi's response you have brought to life a dispute which began about 1832. about whether the animals with short cerata and the animals with long cerata are one or two species. Over the years it has become even more confused by many more names given to animals which are probably the same as one or other of these 'species'. I haven't diligently follwed the argument in the scientific literature so I can only presume that anatomically the two forms are very similar. What your closeup of the head region does show is just how rounded the anterior corners of the foot are in this short cerata form. As I discuss in Jussi's message, this seems to be quite a substantial difference.
What would be interesting would be to see if they have any natural history differences. Some species of Flabellina change from feeding on one group of hydroids to another during the year so food differences may not be a simple thing to look at. Another observation that might be useful would be to look at their egg masses. It is quite possible that their egg spirals might be of a different shape or even their eggs could be markedly different in size. If you would like a little project it would certainly be worth trying to photograph the egg ribbons of the two 'forms' ideally as they are laying them. There may be no marked difference, but it would be exciting if there were,
Best wishes,
Bill Rudman
Flabellina? from Norway
April 25, 2003
From: Kåre Telnes
Hi!
I found several individuals of this aeolid, looking a little like Flabellina verrucosa, which is quite common along the Norwegian coast. However, some details seem to differ:
• Shorter cerata, not organized in the traditional two rows.
• A naked patch on the back.
• Some eggs found on the location, laid in circles. (I am assuming they were laid by these individuals).
They vere found on a current exposed location, near Bergen, on the west coast of Norway. The location is a steep rocky slope, and the depth 25 meters. The individuals were 20-25 mm long.[17 April 2003].
Can anyone help me identify them, please?
Kåre Telnes
kaare.telnes@online.no
Dear Kåre,
This is an interesting find. You wouldn't by chance have have a photo showing the front of the foot more clearly? In the smaller animal in the upper photo it looks like the front edge of the foot could have the front corners extended into pointed 'angles', but I am not sure. I first thought this might be a species of Cuthona, but in that genus the anterior foot corners are rounded. The egg ribbon, if it does belong to these animals, could certainly be that of a Flabellina. In your lower right photo the animal is eating what seems to be a large solitary hydroid - perhaps a Tubularia.
The closest I can come to an identification is a painting of Henning Lemche's of an animal from Jutland, Denmark (Just & Edmunds, 1985), which the authors, suggest is an aberrant form of F. verrucosa. Like your animals, the cerata are short and inflated, and are arranged in a pattern of triangles down the body with bare patches down the dorsal midline. Even the colour is almost identical. Unfortunately, Just & Edmunds only had Lemche's painting, no accompanying notes could be found, and no anatomical information. They suggested it was probably 'unhealthy when painted' which certainly doesn't seem to apply to your animals.
I may be wrong, but it doesn't look like F. verrucosa to me. Hopefully some of our northern European colleagues will have some suggestions.
• Just, H. & Edmunds, M. (1985) North Atlantic Nudibranchs (Mollusca) seen by Henning Lemche. With additional species from the Mediterranean and north east Pacific. Ophelia, Supplement 2: 1-149.
Best wishes,
Bill Rudman
Flabellina verrucosa from Massachusetts, USA
February 4, 2003
From: Alan Shepard
Bill -
Took this photo a couple of weeks ago in Folly Cove, Gloucester, Massachusetts, USA. The nudibranch was about 20mm to 25mm long and was in about 7m of water.
When I initially saw it I thought it was just a variation of F. verrucosa but wasn't sure. Dr. Larry Harris, University of New Hampshire has identified it as Flabellina verrucosa, although a bit emaciated. He notes that the gonads are not fully developed. Andy Martinez, author of Marinlife of the North Atlantic concurs with Dr. Harris' ID.
On this same dive I found Placida dendritica (first time in the cove), Flabellina verrucosa, Aeolidia papillosa, Polycera dubia, Acanthodoris pilosa and Onchidoris muricata. Not bad on a short 40 minute dive in 40f water.
Best wishes,
Alan Shepard
Tolland, CT, USA
alan.chepard@snet.net
Shepard, A., 2003 (Feb 4) Flabellina verrucosa from Massachusetts, USA. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/9065Thanks Alan,
Looks like you've found a good spot
Cheers,
Bill Rudman
Re: Flabellina verrucosa from British Columbia
July 25, 2002
From: Marli Wakeling
Hi Bill,
The third photo in Wendy Atkinson's message is the debated Cuthona punicea feeding on the "raspberry hydoid" Sandra Millen is in process of describing.
Regards,
Marli Wakeling
scubamarli@excite.com
Wakeling, M., 2002 (Jul 25) Re: Flabellina verrucosa from British Columbia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7639Thanks Marli,
I thought it looked familiar, but I was thinking glaucid or flabellinid rather than tergipedid.
Cheers,
Bill Rudman
Flabellina verrucosa from British Columbia
July 19, 2002
From: Wendy Atkinson
Hi,
Can anyone help id which Flabellina these may be? Found at 40-45 feet in Hakai Pass - Port Hardy area, BC, Canada. Are they just variations on the same theme?
Wendy Atkinson
wendyatkinson@attbi.com
Note added 25 July 2002: See Marli Wakeling's message identifying the bottom right animal as Cuthona punicea.
Dear Wendy,
I am pretty sure that the upper right and lower left photos are of Flabellina verrucosa, the white-tipped cerata, the white line on the oral tentacles and the white line down the 'tail' all suggest that species. I am not so sure of the third photo [lower right] however and so if someone with local knowledge can comment I would be grateful.
Best wishes,
Bill Rudman
Re: Cuthona punicea
June 25, 2002
From: Sandra Millen
Hi Bill,
Marli's animals are definitely Cuthona punicea feeding on its prey, the "raspberry hydroid". This species of undescribed hydroid is still in my to do box. I have worked out the anatomy and life cycle. It really is an interesting hydroid and I hope I don't have to wait to retire to find time to write it up.
Sandra Millen
millen@zoology.ubc.ca
Millen, S., 2002 (Jun 25) Re: Cuthona punicea. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7142Thanks Sandra,
Bill Rudman
Flabellina verrucosa from Massachusetts
June 22, 2002
From: Paul Young
My wife and I were diving at Back Beach in Rockport, Massachusetts. We found this critter in about 15' of water. My wife, Charlotte Richardson, photographed this animal. We think it is another Coryphella. It is about 15mm long.
On the same dive we saw another aeolid, a Doto and several Onchidoris muricata, locally called "little white dorid". But our photos of them were not as good as the ones I sent you last year. Not bad for a dive in a spot which is usually used primarily for training dives.
Photo by Charlotte Richardson
Paul
young@underwater.org
Young, P. , 2002 (Jun 22) Flabellina verrucosa from Massachusetts. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/7290Dear Paul,
This is Flabellina verrucosa, about which we've already
said most things. This individual shows two of the features which I think are diagnostic for this species: the white line along the tail extending amongst the last few cerata and the narrow white line on the dorsal side of the oral tentacles.
Bernard Picton
bernard.picton.um@nics.gov.uk
Flabellina verrucosa with hydroids from Canada
April 6, 2002
From: Marli Wakeling
Hi Bill,
Here's a Flabellina verrucosa balancing on a pink-mouth hydroid stalk. I've assumed they ate the orange ones in my earlier photos, but this may show they like both varieties!
DIVE SITE: West Wall,Race Rocks, near Victoria, British Columbia
DEPTH: 45 feet
DATE: March 24, 2002
PHOTO BY: Marli Wakeling
Marli
scubamarli@excite.com
Wakeling, M., 2002 (Apr 6) Flabellina verrucosa with hydroids from Canada. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6632Thanks Marli,
I understand this species is not as fussy as some and is known to eat a variety of hydroids
Bill Rudman
Flabellina verrucosa from British Columbia
March 23, 2002
From: Marli Wakeling
Hi Bill,
Here is another common British Columbia aeolid, Flabellina verrucosa. The dive site is Dodd narrows, near Nanaimo, on Vancouver Island. They are often found on this electric orange hydroid, Garveia annulata.
PHOTO: Dodd Narrows, near Nanaimo, British Columbia, Canada.
DEPTH: 45 feet
LENGTH: 7mm
DATE: June 9, 2001
PHOTO: Marli Wakeling
Marli
scubamarli@excite.com
Wakeling, M., 2002 (Mar 23) Flabellina verrucosa from British Columbia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/6485Thanks Marli,
Bill Rudman
Flabellina verrucosa - photo of tail
July 22, 2001
From: Bernard Picton
Hi Bill,
I've attached a picture of Flabellina verrucosa showing the tail, which I
find very distinctive, but isn't shown clearly in the pictures already on
the Forum.
Locality: Lee's Wreck, Strangford Lough, Co Down, Nthn Ireland
Bernard.
bernard.picton.um@nics.gov.uk
Picton, B.E., 2001 (Jul 22) Flabellina verrucosa - photo of tail. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/4845Thanks Bernard,
Very soon I won't have any excuse to misidentify any North Atlantic Flabellina.
Best wishes,
Bill Rudman
Flabellina verrucosa from New England
June 20, 2001
From: Paul Young
To accompany my message about salmon-gill Flabellina from New England here are photos of the ones which are red or chocolate brown and are locally called red-gills.
Of the red-gills there are elongated ones with a few growths on their backs [lower left photo] as well as the more common ones with completely covered backs [other photos]. We think these are F. verrucosa, F. pellucida, or F. gracilis.
We have seen them eating and spawning on pink-hearted hydroids. These used to be more common in one of our favorite dive spots, Fort Wetherhill, Jamestown, Rhode Island, but over the years the hydroids have become considerably less common and there are fewer red-gills. Both red-gills and salmon-gills get to be 3-4 cm long.
Paul Young
young@underwater.org
Dear Paul,
Terry Gosliner has identified these as Flabellina verrucosa. In the bottom right photo I have included an inset of the hydroid I presume they are looking for.
On the lower left photo the inset is showing the white sreak on the rhinophore which is one of the external identification points of this species. The colour and shape of the head and head tentacles are important in identifying species of Flabellina but as your photos show, when these animals are busy looking for food they don't make it easy for you to photograph their important features.
Best wishes,
Bill Rudman.
Re: Flabellina verrucosa feeding on scyphistomae
February 16, 2001
From: Bill Rudman
I just got a message from Bernard Picton who suggested the scyphistoma in Chad's photo is probably Aurelia aurita so I had another search of McDonald & Nybakken's list and found the following references to feeding on Aurelia aurita 'polyps'. Clearly predation by F. verrucosa on the scyphistomae stage of Aurelai can be an important factor in Aurelia populations, at least in Sweden.
• Hernroth, Lars, & Fredrik Gröndahl. 1985. The biology of Aurelia aurita (L.) 3. Predation by Coryphella verrucosa (Gastropoda, Opisthobranchia), a major factor regulating the development of Aurelia populations in the Gullmar Fjord, western Sweden. Ophelia, 24(1): 37-45.
• Hernroth, L., & F. Gröndahl. 1985a. On the biology of Aurelia aurita (L.): 2. Major factors regulating the occurrence of ephyrae and young medusae in the Gullmar Fjord, western Sweden. Bulletin of Marine Science, 37(2): 567-576.
Cheers,
Bill Rudman
Re: An aeolid from Massachusetts
February 15, 2001
From: Chad Sisson
Dear Bill,
In response to your question: I do not know of any research done involving this specific diet for F. verrucosa. I simply meant that these nudibranchs are rarely found associated with this food, but when they are, they have a very distinct color and morphology. I do not know if they switch to another diet once the scyphistomae have run out, but it wouldn't surprise me if they did take advantage of whatever is around.
As you know, this species has a broad range of diets, from colonial tunicates to stauromedusans, in addition to a variety of hydroids.
Are there many other examples of nudibranchs preying on scyphistomae?
Thanks for your comments,
Chad Sisson
cgsisson@cisunix.unh.edu
Sisson, C., 2001 (Feb 15) Re: An aeolid from Massachusetts. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3797Thanks Chad,
I don't know of anything reported to eat scyphistomes and I can't see any reference to them in Gary McDonald & James Nybakken's wonderful List of the Worldwide Food Habits of Nudibranchs although it's possible the observation is listed under the species name rather than scyphistome or scyphistomae.
Any other interesting observations for the Forum are always welcome
Best wishes,
Bill Rudman
Re: An aeolid from Massachusetts
February 13, 2001
From: Alan Shepard
Dear Bill,
The unidentified aeolids were approximately 1.75 cm or less, or approximately 0.67 inches.
Thanks again for any assistance that can be offered.
Alan Shepard
aetobatus@aol.com
Shepard, A., 2001 (Feb 13) Re: An aeolid from Massachusetts. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3777Dear Alan,
As you can see in the messages from Terry Gosliner and Chad Sisson, your animals are Flabellina verrucosa with a very interesting diet.
Best wishes,
Bill Rudman
Re: An aeolid from Massachusetts
February 13, 2001
From: Chad Sisson
Dear Bill,
I checked with my advisor, Larry Harris, and he agreed that Alan Shepard's aeolids are Flabellina verrucosa feeding on scyphistomae. Note the white color variation and bright-white cnidosacs. Also, they have unusually swollen anterior foot tentacles, probably from being stung by some potent nematocysts. We have documented F. verrucosa with a similar morphology and diet on floating docks in Beverly, MA.
Alan, thank you for the excellent photos, this is a relatively rare feeding type of F. verrucosa.
All the best,
Chad Sisson
University of New Hampshire
Zoology Dept.
cgsisson@cisunix.unh.edu
Sisson, C., 2001 (Feb 13) Re: An aeolid from Massachusetts. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3783
Dear Chad,
Thanks for the message, and my regards to Larry. I've included another part of Alan Shepard's photo to show the scyphistomae stage more clearly.
For those of you unfamiliar with the word, the scyphistoma is the polyp stage in the life cycle of jellyfish. It looks much like a sea anemone and is a sessile, asexual stage which buds off free-swimming jellyfish (medusae) which breed sexually, completing the life cycle.
Chad, when you talk of a rare feeding type, do you mean this is a variety which only feeds on scyphistomes or do they find other food when scyphistomae stage of the jellyfish life cycle is completed?
Best wishes,
Bill Rudman
Re: aeolids from Massachusetts
February 13, 2001
From: Terry Gosliner
Dear Bill,
Alan Shepard's photos look to me like pale specimens of Flabellina verrucosa. This species is highly variable, especially in the color of the digestive gland that is visible through the cerata. It can range from pale pink to red to chocolate brown. The opaque white markings on the oral tentacles and the arrangement of the cerata appear to be characteristic of F. verrucosa.
I am reminded of a story about this species that was told to me by Alan Kuzirian. Hennig Lemche was visiting Trish Morse at the Marine Lab of Northeastern University in Nahant, Massachusetts. He was struck by the variability of various specimens of Flabellina from the area that had dramatically different coloration. He drew beautiful water colors of each variation, convinced that each represented a distinct species. Alan then changed prey species for the color variants and they all had the same coloration. Lemche was still not convinced that these all represented color variants of Flabellina verrucosa that were based on different prey species. However, the evidence was pretty convincing. These variations can sometimes fool the experts!
Terry Gosliner
tgosline@calacademy.org
Gosliner, T., 2001 (Feb 13) Re: aeolids from Massachusetts. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3787Thanks Terry,
Bill Rudman
An aeolid from Massachusetts
February 10, 2001
From: Alan Shepard
Took this photo at a site called Folly Cove in Gloucester, Massachusetts. Depth was about 20' at the base of a granite wall. Haven't seen them at any other local site nor anywhere else in the cove. They do not appear in any of my ID books as far as I can tell. Can anyone offer some assistance?
Photo was taken with a 1:2 macro lens.
Thank you,
Alan Shepard
aetobatus@aol.com
Dear Alan,
Hopefully Terry Gosliner or someone else familiar with the fauna of the Nth American east coast will help us out. Can you give us a vague idea of size?
Best wishes,
Bill Rudman
Flabellina verrucosa from Canada
December 20, 2000
From: Marli Wakeling
Hi Bill,
Here is Flabellina verrucosa from British Columbia, Canada. It is also present in North Atlantic waters, I've been told. It is very common on Vancouver Island. This is a fairly small animal, 1 to 3 cm. usually.
Marli.
scubamarli@excite.com
Wakeling, M., 2000 (Dec 20) Flabellina verrucosa from Canada. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/3312Dear Marli,
Animals such as Flabellina verrucosa, which are found in the northern waters of both the Pacific and Atlantic Oceans are called circum-boreal. You'll see photos on the Forum of this species from the Atlantic coast of USA.
Best wishes,
Bill Rudman.
Brown form of Flabellina verrucosa
August 31, 1999
From: Betsey Hansen
Bill,
Attached are photos of the chocolate and red versions of the Maine sea slug. I believe this is the same slug I found in New York, but I didn't find anything but red ones in New York. There is also a frontal view. Length: about 1 inch (25mm).
Best wishes,
Betsey
BHScuba@aol.com
Dear Betsey,
Thanks for the photos from Maine. Can you give me a little more detail on the locality please? The brown colour form is a colour form of Flabellina verrucosa. The colour in aeolids is often a result of the colour of their food which accumulates in the ducts of the digestive gland, which are in the cerata.
Your photo of the 'red' form is very interesting because it shows an animal which is changing colour. Note how some cerata have a brown duct, some a red, but many have a bit of both. I am not sure which way the colour change is going, but clearly it has recently changed its diet.
For those unsure of aeolid anatomy I have labelled the parts in Betsey's frontal photo.
fc = the often triangular or tentacular corners at the anterior end of the foot - commonly called foot corners or anterior foot corners
m = mouth, ot = oral tentacles, r = rhinophores
Flabellina verrucosa from Maine
August 31, 1999
From: Betsey Hansen
Bill,
I glad to hear that everyone is enjoying my slugs as much as me. Most other divers think sea slugs are boring.
The Maine slugs were taken off York Beach, Maine on an old pier at about 20 feet (7 meters).
I have a couple of other species from New York that I will send you soon.
Best wishes,
Betsey Hansen
BHScuba@aol.com
Hansen, E., 1999 (Aug 31) Flabellina verrucosa from Maine. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1271Re: Flabellina verrucosa? from New York
August 29, 1999
From: Terry Gosliner
Dear Bill,
I am pretty certain that the specimens that Betsey photographed and that you tentatively identified as Flabellina verrucosa is without a doubt correctly identified as F. verrucosa. The main external characteristics for differentiating F. verrucosa from Flabellina gracilis is that the cerata are more distinctly arranged in rows in F. gracilis and there is a more prominent vestige of a notal brim in F. gracilis. Also F. gracilis has a sort of notched head between the junction of the oral tentacles and more elongate anterior margins of the foot'.
I will try to dig out some of my photos of these species from Maine and New Hampshire, especially since they have caused a lot of historical confusion. Alan Kuzirian's review of those species (I think that it was published in J. Moll. Stud. in about 1979) really clarified much of this historical confusion.
Terry
tgosline@calacademy.org
Gosliner, T., 1999 (Aug 29) Re: Flabellina verrucosa? from New York. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1256Thanks Terry,
it would be great to get some more photos showing the variation in F. verrucosa.
Bill Rudman.
Flabellina verrucosa? off Long Island, NY
August 27, 1999
From: Betsey Hansen
Bill,
This slide is of what I believe is Coryphella rufibranchialis. Besides the color difference, this one looks more transparent than the slide from Maine. The one's in Maine also had a chocolate version in addition to the red version, which I did not find in New York. This one was taken in the Atlantic Ocean on a beach dive off Long
Island New York. I found it at about 12 feet (4 meters). They were all found around pink hydroids. Their eggs were laid in thin white haphazard spirals on the hydroids. The slide was taken with a Nikonos V with a 1 to 1 macro. Length approx 1 inch (25mm)
Regards,
Betsey Hansen
BHScuba@aol.com
Hansen, E., 1999 (Aug 27) Flabellina verrucosa? off Long Island, NY. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/1245Dear Betsey,
Thanks for the wonderful photos of three aeolids you have sent. The ones from Maine haven't as yet arrived. Sorry I can't identify them on the spot for you, but I am sure we won't have to wait long.
If this is Coryphella rufibranchialis then it is more correctly called Flabellina verrucosa. There is a history of confusion in the names of this genus on both sides of the Atlantic. I'll put up some comments when we get them definitively identified. I don't want to perpetuate the confusion by further misidentifications.
Your photos are useful reminder to me of how difficult it is for non-professionals to identify species they find or photograph. My first act when I find something I don't recognise is to dissect it and look at the radula to confirm what family or genus is belongs to, because the outside can sometimes be very misleading. I have just posted a page of photos of the radula of Flabellina poenicia which illustrates a tooth shape which is very characteristic of the genus. Looking at your three species I am not even sure they are all flabellinids.
Best wishes,
Bill Rudman.
