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Cuthona amoena

(Alder & Hancock, 1845)


Terry Griffiths A bit of help with this one please about 10mm in length could be Cuthona amoena brown rings on rhinophores and yellow-white pigment or could it be a jve Cuthona rubescens thanks

Terry Griffiths Sorry about 5mm not 10mm .

Anna Nudi Burn How do you find these wee nippers, Griff?!

Terry Griffiths Just look for something out of place.

Anna Nudi Burn I think I need my eyes tested :D

Terry Griffiths Just think how bad it's for me.

Anna Nudi Burn I think I want to be like you when I grow up ;)

Christian Skauge I'm thinking Cuthona rubescens :-)

Brendan Oonk Let me start by saying that I have never seen C.rubescens in real life. But in none of the photos I've seen of C.rubescens it has got brown bands on its oral tentelacles, which C. Amoena has got. In this picture there seen to be (the start of) bands on the oral tentacles. So if this realy is a difference between the two, this is C.amoena

Anna Nudi Burn Seems like sound thinking!

Christian Skauge C. rubescens does not usually have bands on the oral tentacles, according to Thompson & Brown - indicating that they may occur. C. amoena should have reddish brown or olive bands below the tip of the rhinophores according to the same book. I find these bands a little too low for being "below the tip". But looking at the images of both species in Picton/Morrow's Field Guide, I tend to agree with you still... We don't get C. amoena in Norway, so I'm not familiar with it. Or maybe we do, after all? Perhaps Bernard Picton could help us out on this one - after all he helped describe C. rubescens in 1978 ;-)

Christian Skauge Re-examining my own images of this/similar species. It seems I have two different things... Difficult, and who knows what they look like when they are juvenile? You might be right about C. amoena Brendan - and in that case I may have the first image of this species from Norway :-)

Terry Griffiths Thanks all a new one for me too :-)

Kirstie Harris Terry - stop finding new ones! I have enough trouble finding all the old ones :)

Peter H van Bragt Hi Terry, I doubt that this could be C. rubescens. It lacks the continuous streak of white pigment on the oral tentacles. C. amoena is a fair option. The lack of white pigment spots on the cerata tips, the cnidosac being visible in these tips, white pigment spots on teh abck are indicative. Did you see and photograph any spawn close to this specimen and on what hydroid species did you find it? Could be usefull for the ID.

Christian Skauge I have read the descriptions in all my books now and come to the conclusion that I was probably wrong in suggesting C. rubescens. This means I need to talk to my Norwegian experts... I don't think C. amoena has been recorded in Norway, and we might have misidentified this. Please have a look at this image and tell me what you think: http://www.scubapixel.com/component/content/article/8-images/2437-1021-27032011-7885-Cuthona_rubescens.jpg

Rachel Shucksmith Christian looking at my photographs from Gulen, they look more like C. amoena than C. rubescens, although they are little small for me to photograph well.

Christian Skauge This is quite exciting, actually! I hope I'm wrong ;-)

Terry Griffiths Glad to have helped you out lol.

Christian Skauge ha ha thanks :D

Terry Griffiths Christian get off FB and get back to checking your books .

Rachel Shucksmith On habitas it says: The dorsal surfaces of the oral tentacles have a continuous band of white pigment, and this distinguishing feature is present even in juveniles. Which Terry's, yours Christian on Scuba pixel and mine from Gulen dont have....

Christian Skauge True, htat is one of things I noticed as well. This bugger is more speckled - but could it be a juvenile?

Rachel Shucksmith I do defiantly have C. rubens pics from Gulen as one of my individuals defiantly have the white band all the way along the oral tentacles, my other one is more speckled. They were also on different hydroids.

Christian Skauge Yeah, it seems to be two types.

Bernard Picton Christian, I think yours is C. rubescens. Juveniles of both these species have less pigment than adults, so they do get very difficult to identify at 5mm.

Message posted on NE Atlantic Nudibranchs on 06 May 2013
Klas Malmberg Aquatilis This is at nudie from Norway, Gulen. Identified as Eubranchus farrani. Do you agree? This form with the white pigment on the head is quite common in Gulen.

João Pedro Silva Not E. farrani, at least not like any of the several variations I've seen. Not sure what it is, though. I'd consider Cuthona sp.

Klas Malmberg Aquatilis Im not convinced myself as you can guess of that this is a E. farrani. It has typical white pigment on the rhinofores and on the tentakles. It also has the scattered white pigment on the cerata that makes it special - but... I dont know what it is! Sometimes it has a couple of red small pigmentdots on the dorsum but its lacking in this picture.

João Pedro Silva If this had red marking I'd go for Cuthona foliata... but I don't see them here.

Brendan Oonk If it would have had red bands on the rhinofores it could be Cuthona amoena.......?

João Pedro Silva Brendan, I think you're right. It could be C. amoena. The brown bands on the rhinophores may be very subtle: http://www.seaslugforum.net/message/22029

Tony Gilbert It does have a similar colouration to Eubranchus pallidus but I think its C.amoena as wel.

Message posted on NE Atlantic Nudibranchs on 11 Jun 2012
Antoni López-Arenas Cama Do you think this could be Cuthona amoena or foliata? Found in Mataró (near Barcelona in the Mediterranean Sea) at 18m depth between Posidonia oceanica leaves. Its size was around 1-2 mm. Thank you! http://www.flickr.com/photos/alopezarenas/8672317737/in/photostream

João Pedro Silva Why not C. rubescens?

Antoni López-Arenas Cama why not... why yes? :-) Thanks

João Pedro Silva I'm suggesting this due to the "red pigment at the bases of the cerata": http://www.habitas.org.uk/marinelife/species.asp?item=W14730

Antoni López-Arenas Cama but i don't know if is dark red or brown like Cuthona amoena :-P http://www.habitas.org.uk/marinelife/species.asp?item=W14660

João Pedro Silva You may be right. Plus the rings on the oral tentacles... not an easy one to ID.

Egidio Trainito Cuthona foliata is not considered a mediterranean species (misidentified C.genovae); I think that it is Cuthona amoena, Cuthona granosa is quite different with head body, rhinophores and oral tentacles covered with very fine opaque white. On rhinophores and head tentacles bright orange on the outer parts, look at this: http://opistobranquis.info/en/guia-dopistobranquis/nudibranquis-nudibranchia/eolidacis-aeolidina/cuthona-granosa/

Antoni López-Arenas Cama Egidio Trainito, between Cuthona amoena and Cuthona rubescens, do you think it is clearly amoena? Thank you!

Egidio Trainito C.rubescens is not a mediterranean species, I confirm my opinion: C.amoena.

Peter H van Bragt Peter H van Bragt C. amoena could indeed be a realistic candidate. The dark spot in the head region (oesophagus), granular cerat content and dark rings in both rhinophores and head tentacles is what we also see here in the Netherlands in C, amoena. But its not realy easy to give such a species a name from a photograph of such a small specimen. On what sort of hydroid did you find it??

Bernard Picton It is more like C. amoena than C. rubescens; note the brown mark on the oral tentacles, never present in C. rubescens. It isn't quite the same as any C. amoena I've ever seen, but most species look a little different in the Mediterranean.

Bernard Picton We need to start work on the gordian knots.. http://www.plosone.org/article/authors/info%3Adoi%2F10.1371%2Fjournal.pone.0047214;jsessionid=C7E26F234C576859D205953D222F1F8B

Antoni López-Arenas Cama I think that Cuthona foliata can be a Mediterranean specie. In past some authors misidentified C.genovae as foliata, but this doesn't mean that there aren't Cuthona foliata in Mediterranean sea.

Antoni López-Arenas Cama Here you can see the "Updated checklist of the opisthobranchs from the Catalan coasts": http://www.molluscat.com/SPIRA/PDF/Spira_2_3_5.pdf

Egidio Trainito Previously C.foliata was signaled for Malta but the specimen looked like a very small C.genovae, it would be interesting to see Catalan specimens. Thanks for the useful pdf.

Message posted on NE Atlantic Nudibranchs on 30 Apr 2013
Christian Skauge At Bernard Picton's request I'm posting this image of what I thought to be a Cuthona rubescens. He seems to think otherwise, so now I'm a little intrigued... ;-) Photographed at Gulen, Norwegian west coast, March 2010, ca. 22 meters, 1 cm long.

Christian Skauge Are you thinking C. amoena, perhaps?

Bernard Picton I think this could be a different species of Cuthona, perhaps an un-named one. It doesn't have the bold white stripe on the top of the oral tentacles, but white spots and and a brown mark as well, as in Cuthona amoena. The spots on the cerata in white and red-brown are different too.

Message posted on NE Atlantic Nudibranchs on 20 Feb 2012
João Pedro Silva An unidentified aeolid has been bugging me for the past 5 months. All the individuals I found were on Codium in this spot in Sesimbra, Portugal. They were less than 5mm long. Ths spot can be characterized as a plane between 10m and 15m deep with rocks forming small (<1m tall) canyons about 60m long.

Bernard Picton I think it's Cuthona amoena. Look we're not ready for you to start asking difficult questions, just figuring out how this will work!! :-)

Christian Skauge haha was just gonna write that it's probably not a Eubranchus because it lacks the bubbly cerrata, and that it probably was a species outside my range ;-)

João Pedro Silva This was sort of a test to see how this could work :) I say "sort of" because... it's really bugging me :)

Christian Skauge I know the feeling! Good one... too hard for me because I only know much about the northern species... but thanks for putting it out there. You have loads of nice ones ;:)

Bernard Picton Are those green flashes at the base of the cerata real or an artefact of the lighting?

Christian Skauge I would say they're for real.

João Pedro Silva They are real, Bernard. I think I'll put a close up here... right after dinner :)

Bernard Picton No time for dinner - look I've developed repetitive strain injury in my index finger!! :-)

Bernard Picton The head reminds me of Tergipes, it looks very small, I take your point about the pigment on the rhinophores. I wonder what it's eating?

Christian Skauge But otherwise it has pretty much all the traits of a Cuthona, in my eyes...

Bernard Picton Yes, I'm pretty sure of that. I tend to be a bit of a splitter (Christine laughs!) but it could well be an undescribed one.

Christian Skauge Cuthona silva ;-)

Bernard Picton By the rules of ICZN you've probably either just named it or made that name invalid. I'd prefer the former, writing these things up and getting them into journals takes ages. ;-)

João Pedro Silva I've just added a photo album to receive the unidentified photos. I've uploaded two closeups of this one: https://www.facebook.com/media/set/?set=oa.167103413400947&type=1

Christian Skauge True, Bernard. I must learn to keep my gob shut :)

Message posted on NE Atlantic Nudibranchs on 01 Feb 2012
Taxonomy
Animalia (Kingdom)
  Mollusca (Phylum)
    Gastropoda (Class)
      Heterobranchia (Subclass)
        Opisthobranchia (Infraclass)
          Nudibranchia (Order)
            Dexiarchia (Suborder)
              Aeolidida (Infraorder)
                Fionoidea (Superfamily)
                  Tergipedidae (Family)
                    Cuthona (Genus)
                      Cuthona amoena (Species)
Associated Species