Cuthona nana

George Brown Might this be Cuthona nana? Found grazing scyphistoma polyp phase of Aurelia aurita. Pinnacles in the middle of Loch Fyne (location to be confirmed).

Terry Gosliner This looks like Flabellina salmonacea to me.

Joanne Porter Beautiful image George Brown

George Brown Thank you Terry. Checking SSF, the nudibranch does indeed have "subapical white band on cerata". I'll crop and post a close-up of the cerata.

George Brown Thank you Joanne. Are you on the next Seasearch Orkney trip? Can't wait! Was there a couple of weeks ago but it was all wide angle/fisheye stuff. Kept getting distracted finding nudibranchs!

Joanne Porter I will be on the next seasearch trip! Looking forward to seeing you there George Brown. We saw a few nudibranchs but we could have done with some help from you for identifying them.

Jim Anderson Could it be Catriona gymnota?

Marco Faasse I'm not sure which species of nudibranch this is. Anyway, Flabellina/Coryphella verrucosa is known as a predator of scyphopolyps: Hydrobiologia 355: 21â€"28, 1997. A. D. Naumov, H. Hummel, A. A. Sukhotin & J. S. Ryland (eds), Interactions and Adaptation Strategies of Marine Organisms. Abundance, feeding behaviour and nematocysts of scyphopolyps (Cnidaria) and nematocysts in their predator, the nudibranch Coryphella verrucosa (Mollusca) Carina O¨ stman

George Brown Thank you Jim and Marco. I'll be posting a close-up of the cerata later. Anything else I can do to assist id?

Jim Anderson On mature reflection I agree with Marco - Flabellina verrucosa

Jørn Ari Is this a Cuthona concinna or a Cuthona nana? Size 8 mm, from Denmark

Bernard Picton Cuthona concinna, Jorn. The digestive gland inside the cerata is usually this grey colour.

Jørn Ari Thanks Bernard

Niels Schrieken This picture was taken on the english part of the Doggerbank at the wreck Inger Nielsen. The nudibranch Cuthona is well known from the English waters, but what caught my attention was the foraging behavior. With at least 40 individuals encircled around a metal tube eating Hydractinia echinata from the left side of the tube and leaving eggstrings behind. I find it awesome to see.

Christian Skauge Fantasic shot! Talk about teamwork :-)

David Kipling Good grief, amazing! How deep was this?

Niels Schrieken It's about 20 meters deep.

George Brown Incredible photograph of fascinating behaviour.

Julia Nunn absilutely wonderful picture

Tony Gilbert Amazing shot, I am still looking for C. nana on Hydractinia, so every hermit crab with "fur" that comes along! Think I just missed a Cuthona nana on this hermit specimen, as it seems that its had a reverse-mohican "haircut" down the centr... http://www.flickr.com/photos/tonyjgilbert-images/7501686530/in/set-72157630420768730

Christian Skauge How about a picture like that, with two C. nana's mating on top of the hermit...?

Niels Schrieken Yes Christian that is where I am always looking for when I see hermitcrab. But I have never thought to see a tube with nana eating hydractina like this.

David Kipling Am I right in thinking we should be calling Cuthona now Trinchesia?

Niels Schrieken In the world register of marine species cuthona nana is the correct scientific name: http://www.marinespecies.org/aphia.php?p=taxdetails&id=141627

David Kipling There's a thread on one of the other nudi forums about changing all the Cuthonas to Trinchesia. I personally think we should stop doing that, and move to colour and shape-based names, be much easier to identify them! "Mr Yellow Clubby" is far easier to remember than Limacia clavigera, for example ...

Christian Skauge Problem is, there are lots of different "common names" depending on where you are - latin is the only thing keeping the whole thing together... As for Cuthona to Trinchesia - I have no idea whats right.

Niels Schrieken The other way around if I may believe WoRMS. Example Trinchesia anulata -> Cuthona anulata: http://www.marinespecies.org/aphia.php?p=taxdetails&id=534077

David Kipling There's a long thread on the NUDIBRANCH LOVERS group entitled "Trinchesia instead of Cuthona". I think C nana is actually the sole species allowed to still be called Cuthona!

Christian Skauge DNA matching will eventually save the day :)

Jim Anderson The abstract from Michael Miller's paper in the Journal of Natural Histopry Vol 38 Issue 9, 2004 says in closing. "Re-examination of the local Cuthona species led to a re-assessment of several other tergipedid genera based on the arrangement of the digestive ducts. As a result the genus Cuthona Alder and Hancock, 1855 is restricted to one species, C. nana (Alder and Hancock, 1842), and the genus Trinchesia von Ihering, 1879 re-introduced for the rest of the species previously included in Cuthona." Histopry Vol 38 Issue 9, 2004.

João Pedro Silva I'd really love to hear/read Bernard Picton's view on this.

Rudolf Svensen Anybody knows this one? Image captured South in Norway on a dive today. I guess it was maybe 10 mm long.

Terry Griffiths Cumanotus beaumonti i think would be a good starting point.

Floor Driessen Could this be Cuthona nana? (It feeds on Hydractinia echinata) http://www.habitas.org.uk/marinelife/species.asp?item=W14710

Rudolf Svensen I do not the mout/head looks like Cumanotus beaumonti so I guess it is closer to Cuthona nana.

Peter H van Bragt Considering size and number of cerata C. nana comes very close. C. beaumonti has cerata in front of the rinophores and there seems to be too many cerata for a juvenile C. concinna or C. gymnota.

Christian Skauge Cuthona nana would be my guess too :-)

Klas Malmberg Aquatilis At Väderöarna in Sweden we right now have an explotion of Cuthona concinna. So could somebody tell me what to use; cuthona or trinchesia?

Bernard Picton I think it is better for stability to use Cuthona until we get a real (DNA) tree for these Tergipedidae. Bill Rudman argued for this, there should probably be several genera. I'm not certain that Cuthona nana and Precuthona peachii are really the same thing, which would make things even more complicated. Cuthona nana was described from the North Sea coast of England if I remember rightly, under a stone. It would be great if specimens matching that description could be found by someone in the Northern part of our area (Norway, Sweden, Netherlands??). http://www.seaslugforum.net/showall/cuthonadisc

Rachel Shucksmith Had a not very inspiring mud dive to 30m looking for Firework anemones but found Cuthona nana (i think) on the mud and these Doto's (no idea which doto) and Eubranchus exiguus, sharing the same sponge covered scallop shell.

Jim Anderson Following diving on the west coast we have updated the site - 2 additional species and 10 updates. http://www.nudibranch.org/Scottish%20Nudibranchs/index.html

David Fenwick Snr Nice one Jim, fantastic image have enough trouble getting images like that without being underwater.

Jim Anderson Thank you David.

Bernard Picton Great to see two new species. It just shows, it takes years to find all the species in any area...

Jim Anderson ...years and years of looking at hermit crabs for the elusive Cuthona nana!

Jim Anderson Is this Trinchesia amoena or Trinchesia rubescens? 5 mm animal with spawn at 12 m in Loch Fyne, Scotland

John de Jong I would go for rubescens based on the red color. http://www.jojodive.nl/Nudy%20branches/Dutch%20%20Sacoglossa%20and%20Nudibranchia/slides/Trinchesia%20rubescens%20.html

Terry Griffiths Thanks for putting this one up Jim Anderson i also managed to get a few photo's of this nudi the other week when i was up there.

Peter H van Bragt Very sure it's T rubescens. cheers Peter H van Bragt

Erling Svensen Silly question: Have this nudi changed name from Cuthona rubescens to Trinchesia rubescens?

Peter H van Bragt Hi Erling. Some years ago there was some consensus among some taxonomists that only Cuthona nana belonged to the Cuthona family and all others should be therefore renamed to Trinchesia. In my publication on Dutch nudi's (2004) the peer reviewers insisted that it should be like that. It seems that now this has changed again and all are back again in the Cuthona family. Trivial names may change often .... scientific names can change too. In Dutch we call this... voortschrijdend inzicht....ny innsikt! Cheers Peter H. van Bragt

Erling Svensen Thanks. I get mad of all these namechanges...

João Pedro Silva As some of you are aware, me and Gonçalo Calado are just finishing a field guide on portuguese sea slugs with a particular focus on Algarve. We're including 114 species but there are 4 for which we still don't have photos: Cuthona genovae Cuthona thompsoni Cuthona willani Onchidoris depressa If you have some photos of these species (it can be from another place unless there are some very clear variations along the distribution range) and would like to contribute to this field guide (copyright retained by you, of course, with authorship clearly mentioned and a signed copy delivered to you), please send me a message. Thanks!

Gary Cobb Is it possible to say why you are using Cuthona??

Gary Cobb I am building an iPhone App for the Eastern Atlantic -Nudibranch ID and the species list contains 852 species. The area covered is from the Norway down to Cape Town. Good luck Joao!

João Pedro Silva Because of this, Gary: http://www.seaslugforum.net/showall/cuthonadisc

João Pedro Silva Also, the latest Iberian checklist also uses Cuthona: http://www.inoxnet.com/portisub/files/CatalogoIbericoOpistobranquios2006.pdf

João Pedro Silva I've yet to find the reference for the general use of Trinchesia instead of Cuthona (except for Cuthona nana).

Gary Cobb Trinchesia instead of Cuthona We feel that Michael Miller’s paper, in the Journal of Natural History 2004 Vol. 38 Issue 9, being the most recent work in this area coupled with his knowledge and experience with this group gives the decision to change most Cuthona to Trinchesia all the authority for acceptance that is needed. We don’t wish to refute every point made in the discussion listed above but suffice to say it is fair to accept the work until somebody puts in the time and effort to come forward with the information and the argument to dispute it. We think it should be accepted until fairly tested. We agree that science makes little incremental steps in progress and often that is just “nibbling away” at the matter. The whole nomenclature process is a fluid thing. Sure, it may change again later; it might flip flop several times but based on our current knowledge it makes sense to group species upon the currently researched and understood features. We fail to see the confusion. Some workers are by their nature “clumpers” grouping species together and others are “splitters” breaking them up into many different taxons. We don’t think Miller is guilty of being a “splitter”.

João Pedro Silva Still, I'd like to know if that particular study used material from the above species (and others of the same genus from the Atlantic). At least the abstract only mentions NZ species. WoRMS doesn't include the species I mentioned in the Trinchesia genus (http://www.marinespecies.org/aphia.php?p=taxdetails&id=391297) but in the Cuthona genus (http://www.marinespecies.org/aphia.php?p=taxdetails&id=138543).

Gary Cobb See new thread.

João Pedro Silva Orietta Rivolta, you have some nice shots of Onchidoris depressa on Nudipixel. Please let me know if you'd like to help us. http://www.nudipixel.net/photo/00033394/

Orietta Rivolta Ok João you can use my photos :-)))))

Gary Cobb Hey Joao! As you know I am building an iPhone App for the Eastern Atlantic and Mediterranean Sea called Nudibranch ID with so far 850 species. I came across a photo of Calma gobioophaga and would like to ask you if I may have permission to use your photos in this new App. I say photos meaning if I come across any other of your photos may I have permission. Your photos will have your name on each one and listed in the Contributing Photographers thank you view. If you have an iPhone I will send you a promo code for a free App. Thank you.