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Polycera quadrilineata

(O.F. Müller, 1776)


John de Jong Polycera quadrilineata at Zeelandbrug, Oosterschelde, the Netherlands. Camera: OLYMPUS E-330 | Datum: 4-6-13 18:13 | Resolutie: 1280 x 960 | ISO-waarde: 200 | Belichtingstijd: 1/160s | Diafragma: 14.0 | Brandpuntsafstand: 50,0mm (~96.1mm) | Depth abouth 8 meters.

Message posted on NE Atlantic Nudibranchs on 10 Jun 2013
John de Jong Hitchhiker on these Polycera quadrilineata. Shot at Zeelandbrug, Oosterschelde, the Netherlands with Olympus E330, 50mm and +10 diopter. Iso200, 1/100s, F22,0

Message posted on NE Atlantic Nudibranchs on 10 Nov 2012
Rudolf Svensen Anybody knows this one? My closest guess would be a juvenile Polycera quadrilineata? Image captured South in Norway.

Lucas CerCur Do you have other pics of this specimen? What's the bryozoan on which you find it?

Torjus Haukvik I agree. Found a drawing of the color morph in one of my books.

Terry Griffiths I would say some I have seen some this year with this coloration

Arne Kuilman Wow, cool light brownish one indeed.

Message posted on NE Atlantic Nudibranchs on 04 Nov 2012
John de Jong Polycera quadrilineata bij De Zeelandbrug ISO-waarde: 100 | Belichtingstijd: 1/100s | Diafragma: 22.0 | Brandpuntsafstand: 50,0mm (~96.1mm) | Flits: Flash fired with Olympus E330 and 50mm macro lens, 2x Ikelite DS160/161 flashes.

Message posted on NE Atlantic Nudibranchs on 24 Sep 2012
Shôn Roberts Lined Polycera ( Polycera quadrilineata ) Photos of two individual slugs taken at Bull Bay, Anglesey North Wales.

Klas Malmberg Aquatilis Polycera quadrilineata using slimetread to fly in the current.

Bernard Picton I've seen this too - I wonder if it is deliberate to get to a new source of food?

Klas Malmberg Aquatilis I think so - its so common to se and you can se the action when the nudie climbes up om something high on the bottom and releases - I think it deliberate to get to new huntinggrounds.

Message posted on NE Atlantic Nudibranchs on 25 Mar 2012
Nils Aukan Polycera quadrilineata, mating on a kelp frond, by Kristiansund, North sea,14.08-2011.

Nils Aukan Polycera quadrilineata,awsome trippel-mating, by Kristiansund, North Sea

Johny Leffelaer From our cold waters,last september,this Polycera quadrilineata.

Ken Thongpila Very cute nudi and great shot... Love to see them one day!

Manuel Martínez Chacón Polycera quadrilineata.

María Eugenia Suárez Nunca me canso de observarlos. Hay "mogollón".

Message posted on Nudibranquios on 28 Sep 2013
John de Jong Polycera quadrilineata. Just to show the size I took a rule with me. Yesterday at Zeelandbrug, the Netherlands.

Roy Arthur David Lontoh Amazing!

Marcel Ekkel Mooi shot John!/Nice shot John!

Ken Thongpila Very cute nudi and very small.. Nice work!

Message posted on Underwater Macro Photographers on 06 Nov 2011
John de Jong Hitchhiker on these Polycera quadrilineata. Shot at Zeelandbrug, Oosterschelde, the Netherlands with Olympus E330, 50mm and +10 diopter. Iso200, 1/100s, F22,0

Message posted on UWphotographers on 10 Nov 2012
Philippe Velghe Polycera quadrilineata/ Netherlands.

Message posted on UWphotographers on 22 Aug 2012
Yuri Hooker Polycera quadrilineata in Lofoten island, Norway

Anne Diver Beautiful! Great shot!

Message posted on EPAM Nudibranchs on 07 May 2013
David Fenwick Snr Can someone have a stab at this one for me please. It was found today on the lowershore at Tavis Vor, Mousehole, Cornwall. It's 3-4mm in length. It either came off Codium or Rainbow Wrack as it was found in my collecting container just after I emptied it.

David Kipling One of the spotty forms of Polycera quad?

Richard Lord Certainly reminds me of Polycera sp.

David Kipling Four oral processes suggest P. quad?

Jim Anderson Polycera quadrilineata (Müller, 1776)

Christian Skauge Me too think so :-)

David Fenwick Snr Thanks everyone appreciated

Tony Gilbert Interesting colourations, similar to those posted a short while back. This one looks juvenile though, and prob. is if its 4mm. Mouzall is a really nice place, very quaint fishing village, we instead dived Lamorna a couple of years back.

Message posted on NE Atlantic Nudibranchs on 08 May 2012
Tony Gilbert Talking of Scottish Nudibranchs, the Polycera reminds me of a nudibranch that fell off the reef above and glided past to rest on the reef directly in front of me. This was in The Small Isles last July. As yet I've no definitive confirmation, although Joao and I thought it maybe a Polycera species (even though the pic filename below says different). I've never seen this colouration before: http://www.flickr.com/photos/tonyjgilbert-images/5964638520/in/set-72157627183521133 Anyone got any ideas as to whether this is Polycera variation or something else? Thanks

João Pedro Silva This one has a similar pattern although it is clearer it might be Polycera quadrilineata: https://www.facebook.com/photo.php?fbid=2967470797267&set=o.166655096779112&type=1&ref=nf

Message posted on NE Atlantic Nudibranchs on 27 Apr 2012
Robert Roslyn Mullberry Harbour, West Sussex, UK.

Sylvie Omnès i'd say Polycera Quadrilineata (Müller 1776)...

Robert Roslyn Cheers

David Kipling I agree with Sylvie. The other similar common UK species would be Polycera faroensis, which has far more oral processes (those yellow bits at the front, bottom). Compare the two species on habitas: http://www.habitas.org.uk/marinelife/species.asp?item=W13630 http://www.habitas.org.uk/marinelife/species.asp?item=W13620

David Kipling If you look on kelp fronds you can often find dozens of these, grazing the sea mats.

Wilfried Bay-Nouailhat A Polycera quadrilineata thinking it is a Thecacera pennigera ;-) Morgat, Brittany, 5 meters

Lucas CerCur This specimen is very interesting! However, it's clear that is not a Thecacera pennigera. Have you collected?

Wilfried Bay-Nouailhat No, P. quadrilineata have very varied coloration and this one was comic because it looks like T. pennigera

Terry Griffiths Very common around the SW Devon and Plymouth area.

João Pedro Silva Tony Gilbert has similar photos: http://www.flickr.com/photos/tonyjgilbert-images/5964638520/in/set-72157630248775266

Lucas CerCur Nevertheless, this morphotype (and others) would be interesting to study molecularly.

Arne Kuilman Whoa, never seen this yet

Message posted on NE Atlantic Nudibranchs on 09 Jun 2013
Godfried van Moorsel Polycera quadrilineata - Burghsluis Oosterschelde NL another uninvited guest: who's hugging my tail?

Brendan Oonk Could it be a very small Dendronotus frondosus?

Godfried van Moorsel got it!

Message posted on NE Atlantic Nudibranchs on 02 May 2012
Eric van Andel Polycera faroënsis or polycera quadrilineata ??

Gary Cobb Location and size please

David Kipling Yes, I would say ;)

Eric van Andel Zeeland, south-west Netherlands, approximately 1 to 1.5 cm...

David Kipling It has the spots of quad, but how many oral processes do you think it has? It seems half way between quad (four processes) and faroensis (eight).

Eric van Andel looks six to me..... *confused*

Gary Cobb I would say this is Polycera quadrilineata (Muller, 1776)

David Kipling Why do you say that Gary, as opposed to faroensis?

Eric van Andel what's your basis for this choise Gary Cobb?

Gary Cobb The number of processes at the front end 4

David Kipling So what are those two things just outside the central four processes?

Eric van Andel and what are those 2 extra 'things' left and right from the processes called?

Gary Cobb Polycera faroensis can have double that.

Gary Cobb From what I can remember P. faroensis has far less yellow markings and an almost completely white body.

Gary Cobb Polycera faroensis tends to get up to 50 mm or would be considered a larger animal

Gary Cobb Well that's my 2 bits. Hope this helps.

Eric van Andel think I'm convinced Gary Cobb :-}

Jim Anderson Ploycera faeroensis - I've seen lots with yellow spots on their bodies - check here for some http://www.nudibranch.org/Scottish%20Nudibranchs/polycera-faeroensis.html

David Kipling I'm still not clear how we define "oral processes" here (4=quad, 8=faroensis). Eric's picture shows four clear long processes, and then two yellow things next to them which are more flattened. Do these count as oral processes, or are they yellow markings at the mantle edge? The reason I ask is that one of Jim Anderson's pictures is almost identical to Eric's picture, with the four (=quad) processes and two additional yellow bits, and I wonder whether Gary Cobb would call this P. quad instead? http://www.nudibranch.org/Scottish%20Nudibranchs/html/polycera-faeroensis-07.html

Gary Cobb Yes I would call this Polycera quadrilineata!

Gary Cobb Ok...Jim on what basis do you call this latest photo Polycera faeroensis??

Gary Cobb I base my opinion mainly on the number of processes at the front end. The naming of the two species can be subjective as we all know. Individual animals can have characteristics of both species. As non professionals we can only hazard a guess. Just try to match the morphology as best you can and be happy with your result, only looking inside the animal and/or DNA analysis can give us the true identity.

Gary Cobb From Bill Rudman... "It is possible to distinguish P. quadrilineata from P. faeroensis, by using external characters but as both species are quite variable in colour, most of the colour pattern is not that useful. However the best distinction is that P. quadrilineata usually has 4 (rarely 6) oral veil processes, while P. faeroensis usually has 8 or more. ...over to you.

Jim Anderson All my 'difficult' examples were verified by Dr. Bernard Picton. I consider the number and shape of the oral processes to be the clues in this one - it's more faeroensis than quad from the many examples I have seen. Not very precise i know but my best attempt.

Eric van Andel Perhaps Bernard Picton can have a go at this one? :-)

Nils Aukan Dendronotus frondosus + Polycera quadrilineata + Onchidiris muricata, all in one picture,by Kristiansund,North Sea.

Patrik Good Are these critters in their natural environment or is it a studio photo? Do they occur in this constellation (same food source) or did you put them together?

Nils Aukan These three nudibranchs are in their natural environment on top of a kelp frond. Not often three different nudis are that close, but in the spring,april and march we have hundreds of different nudis and many species all over the kelp and hydroid mats. I do NOT take pictures in a studio, only in their natural environment, and have done that since I started diving for 46 years ago, taking pictures from 1968.I only clean the pictures for some backscatter, and make the exposure in 1/250 sec. making black background. Also, I can give blue background with long exposure.

Nils Aukan On the kelp-fronds grow different hydroids and bryozoa. The young Dentronotus eat Obelia,Sertularia and Halecium hydroids. (The big grown-ups are white/yellow and prefer large tubularia.)The Onchidoris eat bryozoa,Membranipora membranocea, which also lives on the kelp. The Polycera quadrilineata eat the same.

Patrik Good Congratulations. Spectacular photos and background info. Your photos look so crisp and fresh. Thank you for sharing.

Johny Leffelaer Again,the Polycera quadrilineata.;-)

Wil Yu This is amazing!

Jim Anderson This looks more like Polycera faeroensis.

Johny Leffelaer Its a thin line between them,can you tell me whats caracteristic for the P.faeroensis,compare P. quadrolineata??

Johny Leffelaer Big mistake from me,indeed its Polycera faeroensis,i was reading your comments on this species,wich i found on the internet,thanks for this.

Philippe Velghe In the foreground a Polycera quadrilineata,in the background a Macropodia rostrata. The Netherlands.

Daniel Beaureperre nice light

Message posted on UWphotographers on 10 Aug 2012
Richard Yorke More Trapanina macculata from the Dorset coast.

Charlotte Bolton Great pics as ever Richard - where/when were these?

Richard Yorke Stennis Ledges on the Dysidea (10/7/10), and North Whitehouse Grounds (8/9/12)

Charlotte Bolton Thanks for the super-quick response! The 2012 sighting isn't in Marine Recorder but I am about to rectify that...

Lucas CerCur The correct spelling is Trapania maculata.

Richard Yorke Sorry, just copied and pasted it from the earlier post, just checked my keywords and it is correct there :-)

Kirstie Harris I wonder how many (if any) of these I've ignored, thinking they're Polycera quadrilineata......I must take the time to look at them properly in future!

Sarah Bowen Yes, definitely - we did the same with a Polycera-like specimen a few years back but something just didn't look right. Then we got Bernard to have a look at it and it turned out to be Trapania tartanella!

Message posted on NE Atlantic Nudibranchs on 28 May 2013
Erling Svensen A very tiny Palio dubia from yesterdays dive in the harbour. A lot of nudis now, so I hope that Bernard Picton will have a great time when I pick him up in Bergen this week.

Peter H van Bragt Erling, this is Palio nothus, not P. dubia

Erling Svensen Jippppiiiiiii. A new spieie.......... Thanks alot......

Erling Svensen ..... specie.......

Christian Skauge Congrats! This one is really cool, and quite rare in Norway :-) Looking forward to seeing you very soon, btw!

Gary Cobb Geeez what's the water temp?

João Pedro Silva Gary, let's look at the bright side: it's above freezing and warmer than in January :) We have a lot higher temperatures and right now it's 13-14ºC here in Portugal. An interesting thing I've been noticing is that some species occurring both in Iberia and much further north (for instance, in the UK, The Netherlands, Norway, etc) do seem to grow a lot more in colder waters. Examples of such species include Polycera faeroensis, Polycera quadrilineata and Limacia clavigera. More bryozoans? More dissolved oxygen? Don't know...

Gary Cobb Buurrrr! My dry suit will keep me from the chill thats for sure Joao. Thanks! Yes I am finding here on the Sunshine Coast (water temp 26C) <- weep! Species from the tropics up north and about 10 years ago we were finding temporate species but not now.

João Pedro Silva I'm not sure if here we are witnessing species spreading their distribution range or we are getting more (and better) documents of observations.... I'm more inclined towards the latter. Initiatives such as the Nudibranch Safari have been producing really interesting results. Above 15ºC and in the summer I change to a semi-dry (can't stand the heat at the surface).

Gary Cobb I know what you mean! I choose the later!

Anna Nudi Burn What a gorgeous little fella :)

Message posted on NE Atlantic Nudibranchs on 04 Mar 2013
Tine Kinn Kvamme From this afternoon dive in Drøbak, Norway. "The kelp forest´s butterfly". Limacia clavigera. Though this one was found on a tube. Approx 10 mm lenght at 18 meters dept.

Rahul Meh-unpronouncable Very nice!

João Pedro Silva We had a kelp bloom in Portugal this year and this usually means lots of polycerids by late summer. Both Limacia clavigera and Polycera quadrilineata were feasting on the bryozoans which grew on the kelp.

Erling Svensen A new dodo. I both hate and love the dodots. They are so beautiful nudies, but still so hard to identify. Anyone? Below the doto there are two juvenile nudies. The doto is less then 1 cm long, so the juveniles is not much bigger than 1 millimeter.

João Pedro Silva The smaller one on the right looks like Polycera quadrilineata. Regarding the Doto... I share your feelings :) PS: you've typed "Dodot". There's also a hate and love feeling regarding diapers :)

Erling Svensen Dotos.... ;-). I say to myself: Stop take pictures of these nudies, but there is something inside that not share that feeling.

Tony Gilbert I think this is close to D. coronata or D. eireana. It depends on how much pigment is down the body, and its colouration. Also, I think it narrows id down if the food source is photographed and confirmed, as many are exclusive feeders. This is something I need to think of well :-)

Christian Skauge I know the feeling - and agree with you both. HATE them! But always have to photograph them anyways...

Erik de Boer Could this be a Doto Coronata, i think it is. Nice Picture !

Tony Gilbert Yep, me too... always on the look out partic. for Dotos.

René Weterings Wauw, very cool picture!

Message posted on NE Atlantic Nudibranchs on 07 Aug 2012
David Fenwick Snr I was wondering if someone could take a look at a nudibranch for me on behalf of Dr. Frank Gloystein. The image was taken in October 2006, at a depth of about 8 m, in Whitesand Bay, Sennen Cove, Cornwall, close to the wreck of Beaumaris.

Brendan Oonk I would call it Polycera quadrilineata

João Pedro Silva I'm not so sure as it clearly shows at least 6 oral processes. It reminds the body pattern of Tony Gilbert's Polycera sp. posted yesterday: http://www.flickr.com/photos/tonyjgilbert-images/5964638520/ However, his shot shows an individual with no yellow pigment on the rhinophores, oral processes, branchia and extra branchial processes.

David Fenwick Snr Yes it reminded me of the same which is why I've posted it here.

Brendan Oonk quadrilineata occasionally has 6

Claire Goodwin I go with Polycera quadilineata too - although the colouration did put me in mind of Thecacera pennigera for a moment! There is a thread here http://www.seaslugforum.net/showall/polyquad which shows a juvenile with similar colouration and although P. quad does usually have 4 processes it can occasionally have more.

Tony Gilbert Re Joao's comment. "However, his shot shows an individual with no yellow pigment on the rhinophores, oral processes, branchia and extra branchial processes." Interesting that you pointed this out, different yet alike. Perhaps a regional variation of P. quad, as it seems from The url Claire supplied that there can be quite a variation. So, the specimen from Davi's shot ties in nicely with my shot from Greenends Gully in Eyemouth, nice one. http://www.flickr.com/photos/tonyjgilbert-images/4907558557/in/set-72157624761052704/. thanks

Message posted on NE Atlantic Nudibranchs on 28 Apr 2012
Eric van Andel Polycera faroënsis or polycera quadrilineata ??

Gary Cobb Location and size please

David Kipling Yes, I would say ;)

Eric van Andel Zeeland, south-west Netherlands, approximately 1 to 1.5 cm...

David Kipling It has the spots of quad, but how many oral processes do you think it has? It seems half way between quad (four processes) and faroensis (eight).

Eric van Andel looks six to me..... *confused*

Gary Cobb I would say this is Polycera quadrilineata (Muller, 1776)

David Kipling Why do you say that Gary, as opposed to faroensis?

Eric van Andel what's your basis for this choise Gary Cobb?

Gary Cobb The number of processes at the front end 4

David Kipling So what are those two things just outside the central four processes?

Eric van Andel and what are those 2 extra 'things' left and right from the processes called?

Gary Cobb Polycera faroensis can have double that.

Gary Cobb From what I can remember P. faroensis has far less yellow markings and an almost completely white body.

Gary Cobb Polycera faroensis tends to get up to 50 mm or would be considered a larger animal

Gary Cobb Well that's my 2 bits. Hope this helps.

Eric van Andel think I'm convinced Gary Cobb :-}

Jim Anderson Ploycera faeroensis - I've seen lots with yellow spots on their bodies - check here for some http://www.nudibranch.org/Scottish%20Nudibranchs/polycera-faeroensis.html

David Kipling I'm still not clear how we define "oral processes" here (4=quad, 8=faroensis). Eric's picture shows four clear long processes, and then two yellow things next to them which are more flattened. Do these count as oral processes, or are they yellow markings at the mantle edge? The reason I ask is that one of Jim Anderson's pictures is almost identical to Eric's picture, with the four (=quad) processes and two additional yellow bits, and I wonder whether Gary Cobb would call this P. quad instead? http://www.nudibranch.org/Scottish%20Nudibranchs/html/polycera-faeroensis-07.html

Gary Cobb Yes I would call this Polycera quadrilineata!

Gary Cobb Ok...Jim on what basis do you call this latest photo Polycera faeroensis??

Gary Cobb I base my opinion mainly on the number of processes at the front end. The naming of the two species can be subjective as we all know. Individual animals can have characteristics of both species. As non professionals we can only hazard a guess. Just try to match the morphology as best you can and be happy with your result, only looking inside the animal and/or DNA analysis can give us the true identity.

Gary Cobb From Bill Rudman... "It is possible to distinguish P. quadrilineata from P. faeroensis, by using external characters but as both species are quite variable in colour, most of the colour pattern is not that useful. However the best distinction is that P. quadrilineata usually has 4 (rarely 6) oral veil processes, while P. faeroensis usually has 8 or more. ...over to you.

Jim Anderson All my 'difficult' examples were verified by Dr. Bernard Picton. I consider the number and shape of the oral processes to be the clues in this one - it's more faeroensis than quad from the many examples I have seen. Not very precise i know but my best attempt.

Eric van Andel Perhaps Bernard Picton can have a go at this one? :-)

Nils Aukan Dendronotus frondosus + Polycera quadrilineata + Onchidiris muricata, all in one picture,by Kristiansund,North Sea.

Patrik Good Are these critters in their natural environment or is it a studio photo? Do they occur in this constellation (same food source) or did you put them together?

Nils Aukan These three nudibranchs are in their natural environment on top of a kelp frond. Not often three different nudis are that close, but in the spring,april and march we have hundreds of different nudis and many species all over the kelp and hydroid mats. I do NOT take pictures in a studio, only in their natural environment, and have done that since I started diving for 46 years ago, taking pictures from 1968.I only clean the pictures for some backscatter, and make the exposure in 1/250 sec. making black background. Also, I can give blue background with long exposure.

Nils Aukan On the kelp-fronds grow different hydroids and bryozoa. The young Dentronotus eat Obelia,Sertularia and Halecium hydroids. (The big grown-ups are white/yellow and prefer large tubularia.)The Onchidoris eat bryozoa,Membranipora membranocea, which also lives on the kelp. The Polycera quadrilineata eat the same.

Patrik Good Congratulations. Spectacular photos and background info. Your photos look so crisp and fresh. Thank you for sharing.

George Stoyle Polycera faeroensis or quadrilineata (?), North Rona, Scotland.

Gary Cobb This is a dark specked Polycera quadrilineata (Muller, 1776)

George Stoyle Thanks Gary Cobb

George Stoyle Thankyou Jim

Jim Anderson George - for Scottish Nudibranch ID's try here http://www.nudibranch.org/Scottish%20Nudibranchs/index.html

Bob Whorton Beauty!

Mimmo Leonardo Calabria Jonica, Trapania Orteai (?)

Fabio Russo Dovrebbe essere Polycera quadrilineata

Mimmo Leonardo Infatti ... avevo il dubbio ... ;)

Message posted on UWphotographers on 24 Feb 2013
Shôn Roberts Lined Polycera ? Photos taken at Bull Bay on 18-05-13 of two individual slugs.

Glynn Phillips Are these from a shore dive?

Shôn Roberts Yes from the shore near the slipway

Wendy Northway polycera quadrilineata?

Wendy Northway can't make out what he's on?

Shôn Roberts one of them is on a Sea Lettuce the other is on what i think is Polyides rotundus.

Message posted on Seasearch North Wales on 19 May 2013
Nicola Faulks Found on the Farne Islands - with its blue and yellow spots, can anyone give me an ID? It was about 5mm long, hence the slightly dodgy photo quality!!

Paula Lightfoot Odd! You can get Polycera quadrilineata with black and yellow dots instead of just yellow stripes and this would be the right habitat for Polycera (eating sea mat bryozoan) but I can't see yellow tentacles around the mouth.

Paula Lightfoot ps drysuit fixed see you tomorrow :D

Nicola Faulks brill, I did wonder if it was an a strange form of polycera, it was very unusual and pretty, but so small and the dots made my camera have a focus hissy fit!! Fingers crossed for tomorrow, see you then!!

Paula Lightfoot Dawn what do you think about Thecacera pennigera? That has blue and yellow spots, usually larger spots than in Nic's photo but not always. If it is this, it would be a very interesting record as the T pennigera records on the NBN Gateway are all south and west coasts. However, T pennigera eats Bugula not sea mat so I guess the evidence is pointing towards a dotty Polycera?!

Paula Lightfoot Actually looking at it again, I can see two oral tentacles and T pennigera doesn't have oral tentacles. Ok Polycera!

Nicola Faulks Ah, the boring answer is usually the right one!! I have recorded it as Polycera....

Message posted on Seasearch North East England on 28 Jul 2012
Henrique Nascimento Catarina Polycera quadrilineata Sesimbra - Portugal 20130724

Yutaka Takizawa Nice Shot......(^。^)

Henrique Nascimento Catarina Thnaks Yataka Yutaka Takizawa...:)

Message posted on Scubashooters.net on 25 Jul 2013
Henrique Nascimento Catarina Polycera quadrilineata 20120719

Message posted on Scubashooters.net on 25 Jun 2013
Holly Latham Christian Skauge thanks for the post on Polycera quadrilineata, cleared up a question we had over the summer when we found hundreds of the 'zebra striped' variety at Durgan (Cornwall)! Despite their numbers I still never got a good/sharp picture of one either...

Christian Skauge Right, we this variant a lot in Norway, especially this time of the year. Later on the tend to lose the black or blue stripes :-)

Anna Nudi Burn I just love the colour variation, especially when there is so much black like this (the ones I have seen lately have mostly just had black on the rhinophores). I know they're common, but they are so pretty :)

João Pedro Silva This variation is rare here in Portugal. Only seen it less than half a dozen times. On the other hand, the white ones are very common.

João Pedro Silva Here's the darkest I've found in Galicia, Spain: http://www.flickr.com/photos/jpsilva1971/7166442158/

Lucas CerCur I remember to have seen similar specimens to Holly's one in 1988, from Sagres, Algarve (S. Portugal).

Antoni López-Arenas Cama In Costa Brava are common... but I think that dark colours only appears on adult Polyceras. A recent photo of Polycera matting: http://www.flickr.com/photos/alopezarenas/8775639884/

Message posted on NE Atlantic Nudibranchs on 03 Feb 2012
René Weterings "Polycera quadrilineata" Found in the Eastern Scheldt in the Netherlands, my personal favorite nudi over here.

Christian Skauge Beautiful picture of a beautiful nudi :-)

Message posted on NE Atlantic Nudibranchs on 12 Oct 2012
Anna Nudi Burn Polycera quadrilineata - colour variation? Meadfoot - Devon, UK

David Kipling Yes, you occasionally get this black version, often in grazing groups with the more regular white/orange morph. Very funky!

Message posted on NE Atlantic Nudibranchs on 12 Sep 2012
Nathan Jeffery Is this a Polycera quadrilineata? Was observed free floating at Weasel Loch, Eyemouth and allowed to settle on a glove for the photo. Just over 1cm in length. No idea what it was originally attached to. I have never seen one with the black markings.

Christian Skauge Yes, P. quadrilineata :-)

Nathan Jeffery Thanks.

Tony Gilbert P .quads can have black markings, the ones I've seen have been mottled, so its quite interesting to see this with continuous. Seems to be quite a number of P. quad variations.(they prob. need id'ing as distinct variations). Its usual food is bryozoan sea mat, which of course is all over kelp and since Weasel Loch sides have a head of kelp then its not surprising its fallen off :-) How did you find entry/exit -> last month we struggled over the large boulder in surge. Its not an easy site, but rewarding with marine creatures.

Nathan Jeffery Entry / exit can be a pain. I love the site, but normally only dive it around a high tide to try and avoid the boulder scramble. However 2 dives at the site in a day, the boulder scramble is unavoidable. Always worth the effort though.

Julia Nunn yes Polcera quarilineata - also seen many with balck markings, although not continuous as yours is

João Pedro Silva Although less common than the white translucent, the gray ones can also be seen here: http://www.flickr.com/photos/jpsilva1971/7166442158/

Message posted on NE Atlantic Nudibranchs on 07 Aug 2012
Gonçalo Calado First record of Polycera quadrilineata to the Gorringe Bank (WSW Portugal)

João Pedro Silva 36° 30′ 30″ N, 11° 20′ 0″ W http://goo.gl/maps/0ihjA

Message posted on NE Atlantic Nudibranchs on 29 Jul 2012
O Gajo Dos Olivais From my dive today. Polycera quadrilineata, on top of codium. I found a lot of them today, all on codium.

Message posted on NUDIBRANCH LOVERS on 04 Aug 2012
Henrique Nascimento Catarina Polycera quadrilineata (I know this not an usualy way of take a photo to a nudi, but this one just give me this part of him, so............. this is a crop, this nudi have more or less 5mm length)

Message posted on NUDIBRANCH LOVERS on 05 Apr 2012
João Pedro Silva A very small Polycera quadrilineata feeding on Membranipora membranacea. Canon EOS 350D in Ikelite housing, 2x SB-105 strobes, Canon EF f/2.8 100mm USM macro, f/18.0, 1/200s, ISO 100.

Message posted on Underwater Macro Photographers on 09 May 2012
René Weterings "Polycera quadrilineata" Eastern Scheldt, The Netherlands Olympus E-PL2 with Olympus housing 14-42mm @ 42mm with Subsee +10 Dual Inon strobes f/22 1/160s ISO200

Wim van Capel Wat is hij helder

Funtimem Blue is that in the netherlands ?

René Weterings Yes!

Message posted on UWphotographers on 12 Oct 2012
Henrique Nascimento Catarina Polycera quadrilineata Portugal-Sesimbra 2012.07.19

Message posted on UWphotographers on 11 Sep 2012
João Pedro Silva Has anyone ever did a "heat map" of the number of species observed per time of the year? For instance, here in Portugal in May-June one can see 20+ species in a single dive but barely exceeding 10 species during the winter months.

Brendan Oonk Thanks to "Stichting Anemoon" and their MOO-project we have good data on seasonal occurance of nudibranches in the Netherlands. The molluscs Atlas that will be published next year contains some graphs showing this seasonal shift. It might be posible to combine these graphs with watertemperature data..... Not sure who has the time, and the wish to do this though

João Pedro Silva Looking forward to see the Atlas. My idea for that map was restricted to the NE Atlantic where we have some species occurring more frequently in different periods in different areas, like Limacia clavigera or Polycera quadrilineata. Not sure these yearly variations are temperature related.

Peter H van Bragt Hello Joao, best nudi spotting along the Dutch coast is for sure late spring (May-July). up to 15-18speciesin a weekend by a single diver. Water temp is than approx 14-16 degrees C, I do not have the data with me where I am now. As far as I know the record is 13 species on one single dive out of a total of 57 species ever been recorded in the Netherlands. Winter time water temps drop here to 0-2 degrees C. Few nudis like this, but most species larvae seem to survive OK. Cheers Peter

João Pedro Silva Thanks, Peter! That period coincides with the peak of nudibranch diversity also here in Portugal, only with a few exceptions like Cadlina laevis and Spurilla neapolitana which appear to be more frequent during the winter. Yes, many species can be found at any time, namely most Felimare villafranca, Felimare cantabrica, 'Felimida' purpurea, Flabellina babai and others. Water temperature has been "strange" during the past few years frequently with 18-19ºC during autumn and 13-14ºC in August. But the temperatures here are usually between 13ºC-19ºC, being 15-16ºC the most common values (and these can occur at any time of the year, it's 16ºC right now). I don't know the "national record" but my personal record until last June was something like 18 or 19 species during a single dive... then I had several dives over 20 species until I got to see 26 during a single dive on the 20th of June.

Peter H van Bragt Hello Joao, we also have some typical winter species, e,g. Aeolidia papillosa: juveniles start in september, they develop through winter, spawn and die in early spring. At your place water temps seem to be rather stable, here they differ greatly between summer and winter and this causes big differences in biodiversity. How large is the Portugese nudi fauna list (incl. species that are extreme rare or have not been seen for a while)?

João Pedro Silva We have ~140 nudibranch species. Latest checklist (2004) has 215 opisthobranchs. Mine and Gonçalo Calado's recent field guide has 115 species (95 nudibranchs and 20 other opisthobranchs) including some which were not included for Portugal in the 2004's checklist (yet present in the checklist as it includes the entire Iberian Peninsula plus the archipelagos of Açores, Madeira, Canarias and Baleares).

Message posted on NE Atlantic Nudibranchs on 06 Dec 2012
João Pedro Silva A surprise find in today's dive just outside the harbour of Sesimbra, Portugal.

Christian Skauge Those are just AWESOME!

João Pedro Silva I had some doubts regarding the ID: either it was T. pennigera... or some other nudibranch dressed up for the Carnival. No kidding, later in the afternoon Sesimbra got the Clown Parade (one of the local events of the Carnival).

Bernard Picton Yes, the way they blob about makes me think of clowns too João. I hadn't seen them for years until 2010, when they were in Pembrokeshire and Sark (Channel Isles).

Terry Griffiths Does that make me lucky as i get to see them every year.

Bernard Picton Where do you see them Terry? They are one of the species which have been reported from Australia and Japan, with a suggestion that they hitchhiked round the world on bryozoan covered ships hulls. Equally though it could be that there are several spotty Thecacera species.

Terry Griffiths Now there's a thing about Eastern Kings in Plymouth it's right next to the ferry port ,i managed to see 2 on a dive last year not too far for you to come and dive it.

Richard Yorke This one was taken at about 14m just out of Poole in Dorset last June http://www.richardy.co.uk/Nudibranchs/content/110626_160820_E_520_large.html

Bernard Picton Thanks Richard, it will be a good idea to build up a few photos of this species to see how much variation there is in our area. I think the Japanese ones have different sized spots, which wouldn't mean anything if we were looking at Polycera quadrilineata perhaps.... http://www.seaslugforum.net/showall/thecpen

Ross Bullimore http://www.facebook.com/photo.php?fbid=10151307213560368&set=a.255856625367.299739.711315367&type=1&theater

Ross Bullimore (above image) from the east side of martins haven - one of two or three individuals between 12 - 14m - only had them recorded them at Martins Haven though (I think.....)?

Kate Lock We have recorded them at at least 6 sites in the Skomer MNR not just Martins Haven...along with other areas in Pembrokeshire. I remember one year having several on a dive in the Cleddau too.

Message posted on NE Atlantic Nudibranchs on 20 Feb 2012
Taxonomy
Animalia (Kingdom)
  Mollusca (Phylum)
    Gastropoda (Class)
      Heterobranchia (Subclass)
        Opisthobranchia (Infraclass)
          Nudibranchia (Order)
            Euctenidiacea (Suborder)
              Doridacea (Infraorder)
                Polyceroidea (Superfamily)
                  Polyceridae (Family)
                    Polycerinae (Subfamily)
                      Polycera (Genus)
                        Polycera quadrilineata (Species)
Associated Species