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Cuthona viridis

(Forbes, 1840)

Paula Lightfoot Is it Cuthona viridis? Two seen close together on a dive near Sunderland today.

Ian Smith I don't think the reddish rhinophores and long white oral tentacles are right for C. viridis. I've never seen C.rubescens, but, from what I can make out, yours looks like the plate in Thompson & Brown except for colour, but ok as text says it is green after feeding. Maybe someone with experience of rubescens can be more certain.

Paula Lightfoot I can see a reddish brown band around the rhinophores now you mention it - I wish I'd managed to get better photos but it was very tiny - not sure if they'll be good enough for a positive ID...

Erling Svensen It look like C. rubescens for me.

Floor Driessen Why isn't it C. amoena?

Paula Lightfoot C amoena can be olive green but would have a reddish brown or olive band around the oral tentacles? Just reading from Thompson's Benthic Opisthobranchs not from personal experience! I could try cropping the photo as Peter has suggested but the resolution is really too low I think.

Erling Svensen I have quite green rubescens pictures from Norway, and it look like it is this one. But the sice is also important. I have never seen rubescens bigger than 1,5 cm.

Paula Lightfoot They were definitely smaller than that!

Erling Svensen OK. Here the C. viridis from Norway.

Bernard Picton The continuous white stripe on the oral tentacles is typical for C. rubescens and distinguishes it from C. amoena. The ceratal contents can be green, as Erling says.

Paula Lightfoot Just looked this up - there are only two east coast records of this species on the NBN Gateway, they are from the MNCR review in 1993 and one is for the exact same site where I was (Salterfen Rocks) and the other is just over 1km to the south of it.

Paula Lightfoot ...oh bummer just realised what that means - after all that, I haven't even put a new dot on the map! Thank you very much for all the ID help though, this is a new species for me :)

Message posted on NE Atlantic Nudibranchs on 11 Aug 2013
Erling Svensen Two strange forms of nudi - a Flabellina lineata and a Cuthona viridis. Agree?

Message posted on NE Atlantic Nudibranchs on 20 Feb 2013
Nils Aukan Nudibranchs,Onchidoris muricata on a sea-squirt+Cuthona viridis on a hydroide,Kristiansund-Norway,30.01-2013

Message posted on UWphotographers on 01 Feb 2013
Justin Evans I'm hoping someone can help with the ID this for me as I'm drawing a blank on a species of nudi with green/yellowish cerata. Taken last Saturday on the Far Mulberry off West Sussex, 11m depth.

Richard Shucksmith Coryphella gracilis? Green variety? or Cuthona viridis?

Erling Svensen Cuthona viridis

Jim Anderson Trinchesia viridis I think

Justin Evans Many thanks everyone.

Brendan Oonk Flabellina gracilis forma smaragdina

Justin Evans Having looked at Cuthona/Trinchesia viridis on habitas.org.uk, the description doesn't quite match the ones I saw an photographed. In particular the cerata have no streaks or spots of white colouring on the surface, they are plain green colour to the cnidosacs at the tip. And the brown coloured jaws are said to visible through the head in viridis. Therefore, I think these must be C.gracilis var smaragdina which have no white spots or lines on the cerata and also have the white marking on the tail, as per the photo. I haven't seen either species before, so if I'm wrong please do let me know.......I'm no expert!

Christian Skauge Looks like a Flabellina to me :-)

Brendan Oonk Yes Dawn, it is F. gracilis... When its food source is different, it turns green.

Ian Smith See http://www.conchsoc.org/node/3989 click on image to enlarge.

Message posted on Seasearch Identifications on 29 Apr 2013
Kerry Lewis Here's a Cuthona caerulea.... and a Cuthona somethingelsus maybe? I know they aren't great shots, but any offers?

David Kipling Yes, Cuthona viridis. Bright green ceratal contents give it away (as name hints).

Kerry Lewis I wondered that... I hoped that! Two new ones! :-)

Kerry Lewis Richie West how did your piccies of these two come out?

Richie West I still haven't gone through my pics from Scotland yet, that's how far behind I am with my photos... I'll have a look now xx

David Kipling You do realise that pretty much everyone on the survey saw Cuthona caerulea apart from Sarah? She's not happy!

Kerry Lewis Sarah, if it's any consolation, I have the same relationship with Okenia.

David Kipling Doesn't help that the only time I've seen this species underwater was on the fish survey 4 years ago, and I failed to show it to my buddy at the time :(

Richie West Cuthona caerulea was clear in my pic Kerry but C. viridis was out of focus, your photos were better

David Kipling Oh so Richie saw it as well ... !!!

Kerry Lewis Well... to be fair, I don't think Richie had the foggiest what I was pointing at... he just stuck his camera in vaguely the right direction and got lucky...

Richie West As usual though David I had no idea what I was looking at until Kerry told me on the surface

Richie West (she's always right lol)

David Kipling Even when she's not!

Richie West *gasps!* perish the thought

Kerry Lewis Always when I'm not.

Erin Smyth Pretty.. . . .

Richie West I may yet be able to crochet Sarah her very own Cuthona collection

David Kipling Depends if you want her to fill it with lead shot and chuck it at you!

Richie West I already have a very hush-hush order from Kerry for an Okenia elegans for her bcd pocket, although I think Kate and Aran's plasticine version will take some beating.

Richie West After the crochet blouse with matching headband from my new pattern book that is

Sarah Bowen You lot will get chucked out of this group for hijacking perfectly sensible threads with this sort of craft nonsense!!! But yes please, I'd love a crochet Cuthona!

Richie West I will pay particular attention to the diagnostic features with my crochet to make sure it's on-topic

Kate Lock Well done Kerry Lewis - definate nudibranch queen award. I have just checked the Skomer MNR nudibranch list and neither of these species have been officially recorded in the Reserve before!! (although it looks like David Kipling is claiming to above he did not tell us and obviously did not complete a form!!)..... Would you mind doing an Observer form for the dive so we can have these as official records :)

David Kipling My spot was on the 2009 fish survey on Rye Rocks, and I remember someone who shall remain nameless saying "oh no, I don't want a Seasearch form done for the dive, we've done Rye Rocks to death" or something to that effect ;)

Erin Smyth Do you think if we made the surveys for nudibranchs people would hunt for and photograph fish?! ;-)

Message posted on Seasearch Identifications on 24 Jul 2013
Gary Cobb Nice to see the species list for the Nudibranch Safari Norway. The species list on the website (http://www.scubapixel.com/blog/41-blog/blog-2013/20545-nudibranch-safari-species-list) is presently showing ALL authors and dates with brackets. According to Bracket Convention only species that have Genus changes get brackets. ( ) Bracket Convention Changes of scientific names are inevitable and they often upset or annoy the uninitiated. There is one simple way to recognise that changes have occurred. Under the international set of rules in Zoology the author’s name is put into brackets when the species name is changed to a genus different from that in which it was originally described. For example Doris sanguineus Rüppell & Leuckart, 1830 becomes Hexabranchus sanguineus (Rüppell & Leuckart, 1830) when it is recognised formally that the species belongs in Hexabranchus.

Christian Skauge Not being a scientist, I wasn't aware of this at all... :-) But no problem, I have updated the list and it should now comply with the data found at WoRMS: http://www.scubapixel.com/blog/41-blog/blog-2013/20545-nudibranch-safari-species-list

Gary Cobb Just to finish up your species list properly you must treat any parts of the names that are not genus or species names in non-italic. In the case of the 3 Doto species with cf. cf. is not italics. Any names that have sp. sp. is not italics. And the genus authorship is Undescribed. When you include a species name that is undescribed you do not include any authors because there are non... They are undescribed. You use the word Undescribed only with no brackets.

Christian Skauge Well, let's not get carried away... It's just a list showing what we found, not a scientific paper, Gary :-) But thanks, I guess.

Christian Skauge And Bergh did describe the Janolus genus in 1884 ;-)

Christian Skauge There' the list is updated again with Gary Cobb's kind suggestions :-)

Gary Cobb One last thing that can help is if you have more than one of the same genus that are undescribed and names with sp. a number can be assigned and is not italics. Example: Janolus sp. 1 Undescribed Janolus sp. 2 Undescribed The numbers are only valid for an individuals list. That way you can reference that species photo for instance. Janolus is italics and sp. 1 are not italics. Plus the genus part of a name always begins with a capital letter. The species part of the name is non-italics.

Gary Cobb Christian I'm not getting carried away just trying to help make your list correct. Sure it is not a scientific paper but the way you are listing the species is scientific and should be so. I am no scientist either but over the years I have been reminded by scientists how to present a list correctly. After all if you are going to present a complete list I am sure it may of interest to scientists at some time and you don't want to be viewed as an amateur. The reason I have given you this information is not only to help you but to help others that may not know scientific nomenclature. Keep up the good work:)

Christian Skauge Ah, sp. also not italics... *back to the drawing board* But the species NAME should be in italic - like the Genus, I'm sure! Thanks for you help and input Gary :-)

Gary Cobb sp. is not a name it is an indication of a yet to be descirbed species. Other naming nomenclature that does not get italics are aff. and cf. I am only too glad to help you learn something you did not know and will enhance your Nudibranch future!

Christian Skauge Right, cf. and sp. are non-italic but in for instance Cuthona viridis both are :-)

Gary Cobb Ps Christian your species list looks great. Well done:)

Christian Skauge haha thanks - and for you help too :-)

Message posted on NE Atlantic Nudibranchs on 31 Mar 2013
Animalia (Kingdom)
  Mollusca (Phylum)
    Gastropoda (Class)
      Heterobranchia (Subclass)
        Opisthobranchia (Infraclass)
          Nudibranchia (Order)
            Dexiarchia (Suborder)
              Aeolidida (Infraorder)
                Fionoidea (Superfamily)
                  Tergipedidae (Family)
                    Cuthona (Genus)
                      Cuthona viridis (Species)
Associated Species