Tritonia lineata

Erling Svensen Yesterday, Stavanger, Norway, 35 meters deep. Tritonia lineata - the biggest one I ever seen. Really frightening one..... ;-)

Kirstie Harris How big? :)

Erling Svensen 2 cm

Kirstie Harris Wow, a monster! ;)

David Kipling It does look like a little Viking longboat with pairs of rowers ...

Erling Svensen Yes, just waiting to arrive UK and rape all the women.....

Andy Horton How long please?

David Kipling 2 cm

Erling Svensen This must be the evidence.....! Here are the Tritonia lineata in the middle of the food-table.

Klas Malmberg Aquatilis SÃ¥ snyggt!

Rudolf Svensen Tritonia lineata. Image captured in Stavanger Norway one week ago.

Erling Svensen Anybody that knows the hydroid in the right upper corner on this picture? Do you think this also could be food?

Bernard Picton There is a Sarcodictyon polyp just below the head of this Tritonia lineata. I think we need to check in places where there is apparently no Sarcodictyon....

Erling Svensen Agree.....

Erling Svensen When diving at the Tritonia lineata, the wall have some species that I never have seen any other place. It looks like some kind of sea anemonies, but the grow in a kind of chain (left on the picture). Almost all the pictures from this location I can see this strange animal. Does anybody know what this specie may be?

Wilfried Bay-Nouailhat I think it's the stolon of Sarcodictyon rosea

Erling Svensen I have asked my good friend in Bergen, Torleiv Brattegard, and he agrees with you, Wilfried. Thanks a lot. So maybe the S. rosea is the food for this tine nudy?

Bernard Picton Well done, Erling, we speculated that Tritonia lineata fed on Sarcodictyon (I think Sarcodictyon catenata and roseum are synonyms) in the nudibranch guide, mostly because it was the most likely candidate as food. This looks like good evidence. I must ask Kate Lock to look closely in Pembrokeshire where T. lineata is common but we couldn't see Sarcodictyon at the same sites.

Erling Svensen Hi again

Erling Svensen I sent your message, Bernard to Torleiv. I sent his answere to Google translater, and he said: Hello again I have looked at Worms (www.marinespecies.org) and looked at Stolonifera which now has the status of the order. There are 6 families in Stolonifera totaling 29 families so there is little to take off. I went into the family Sarcodictyon which listed eight species. The information about all species are controlled by a Dutchman - Leen van Ofwegen - a little messy specialist!. It is strange that information about the distribution given only for Sarcodictyon roseum, and it is reported from the eastern Atlantic and Mediterranean. Now S. roseum described from the Mediterranean by the German Rudolph Amandus Philippi (1808-1904) and S. catenate append tar by the Englishman Edward Forbes (1815-1854). Forbes took part in an expedition to the Mediterranean in 1841-42, and his art is described in 1847. So there is a possibility that his art can come from Britain or the Mediterranean Sea. Now I have been looking in the Oscar Carlgren (1865-1954) his book on Koraldyr (in Danish fauna vol 51, 1945), and there are mentioned only Sarcodictyon catenatum Forbes in Scandinavia and spread with the same depth as I mentioned in my previous email. Things indicate that Lopez-Gonzalez and Picton's right, and that Carlgren was a good specialist. I should probably change the information I have on my list!! best Regards Torleiv Thought this would be of any interest.

Klas Malmberg Aquatilis Very interesting but there must be more things that T. lineata feeds on? Sarcodictyon isn´t very common in Sweden but we find T.lineata on regular basis. Any more suggestions on foodhabits?

Bernard Picton Yes Klas, this is exactly what puzzles me. Tritonias all (say that and someone will think of an exception) seem to eat octocorals, but we don't have many octocoral species in our area that T. lineata could be eating. Normally they seem to be wandering about on silty rocks. I wonder if the Sarcodictyon is there, but under the silt, or beneath stones?

Kate Lock I shall collate a folder of all our T. lineata photos in Pembrokeshire and see if we can get any clues from those.

Bernard Picton OK, Kate, I had a look at my photos and made an album, "Tritonia lineata looking for next meal".

Sarah Bowen I've just added a picture to that one after a quick trawl of our Tritonia pictures from North Pembs. It's amazing what turns up on the pictures when you have a really good look! Yes, there are Sarcodictyon polyps; perhaps not in every picture but certainly recorded from every dive where a T. lineata was recorded.

David Kipling I've just added some more - again, when we see T. lineata we see Sarcodictyon. All we need now is the shot of the nudi actually eating one ...

Erling Svensen Did a dive yesterday with my brother in Stavanger (yes, its in the city itself - in the harbour). Dived down to the "hundreds" of Tritonia lineata. Got one picture with 3 nudies on - all in different size. Nice, or.... :-)

Christian Skauge Very cool picture! It seems this species is not at all uncommon, and maybe has its peak this time of the year. That would explain why its so uncommon later on. I saw the same thing with the Hero formosa.

Marta Pola Could you collect some specimens for molecular studies for me? That would be great for my research!

Erling Svensen Marta: I do not know when I will be in Stavanger at this spot for diving next time. Its 1,5 hours drive from Egersund where I live. May be my brother Rudolf will dive this spot earlier than me, so an option is to ask him about collecting some. We can keep in contact. Do you put them in alcohol or formalin?

Marta Pola alcohol, please. And pictures...It would be great. Thanks

Rudolf Svensen Maybe we will dive there within the next two weeks. How many do you need?

David Kipling Erling, do you want to start a Tritonia lineata album and post this picture in it? Other people can then post their own examples as well.

Marta Pola That would be great David. And 5 specimens will be great Rudolf. Thanks!

Rudolf Svensen Hi Marta Pola . We dived the Tritonia lineata spot today. It seem like the slugs have grown a lot since february, but still there are Tritonia lineata in all sizes. I collected 5 specimens for you, but the problem is I have no alcohol, well I have beer, but I do not think that is good for nudies ;-) so I see if I can get some tomorrow. For the time they live in a big bucket. The temperature outside is the same as in the water, so I hope they will live. So if I get the alcohol tomorrow, how do I get them to you? You can contact me on e-mail rudolf@uwphoto.no

Christian Skauge Worst case let me know Rudolf, I have a handful of small collection boxes with alcohol - I can send one :-)

Erling Svensen Rudolf - I have still 1 - 2 liters left after the 10 liter barrel bought by a fishing-boat 15 years ago for other purpose than nudies..... Bernard used some of it 3-4 years ago.

Rudolf Svensen Erling. Can you send some to Stavanger quite quck?

Sarah Bowen Following on from David's comment, there's already a small album called Tritonia lineata looking for next meal; see if you can drop them in there!

David Fenwick Snr Is it possible to identify this egg mass, was found under a rock on the lowershore at Little London reef, Marazion, Cornwall. 24.08.13. Thanks.

Erling Svensen Looks like Flabellina verrucosa for me.

David Kipling Tritonia lineata does nice little spirals too, but then again I think a few other species will...

Arne Kuilman Get this card or ask them: https://www.facebook.com/ZoekkaartNederlandseZeenaaktslakken I've got one at home and will have a look for you later.

Brendan Oonk I don't think yoy will find it on that card Arne. These eggs don't look like they are by a species of nudi that lives in The Netherlands...

Arne Kuilman It's not on the chart indeed )-: circlewise it's kind of like Elysia eggs.

João Pedro Silva The eggs I've found from Elysia viridis were much smaller: http://www.flickr.com/photos/jpsilva1971/7741931486/

Arne Kuilman I meant look like. Elysian doesn't lay under rocks, just the spiral pattern

Erling Svensen Looks like these...... http://uwphoto.no/shopexd.asp?id=14044

Brendan Oonk Erling is that the reason you said they were Flabelina verucosa eggs ;)

Erling Svensen Yes, it is. They are quite typical in the outher edge, so for me they looks quite F. verrucosa like.

Erling Svensen In winter we have millions of F. verrucosa, the most common nudi in Egersund and Stavanger. And lots of eggs.

Bernard Picton Cornwall is too far south for F. verrucosa. On the other hand I don't know these eggs I'm afraid. Aeolidiella glauca does lay a straight spiral a bit like this.

Brendan Oonk It is not A. glauca.

Erling Svensen Could be this verrucosa think it is too cold here up in the North and will expand the summer by mooving South?

Brendan Oonk Here you can see A.glauca + eggs http://www.natuurbericht.nl/?id=2727

David Fenwick Snr I'm still trying to find a sea slug to match up with it at the moment but nudibranchs seem few and far between at the moment. The only sea slug found today was a 2mm Palio nothus, a sea slug that has consistantly turned up for us throughout the year this year.

David Fenwick Snr Another image of A. glauca. http://www.conchsoc.org/node/5853

David Kipling https://www.facebook.com/photo.php?fbid=332958726789556&set=oa.266943763416911&type=3&theater

David Kipling T. lineata caught laying eggs like this ...

David Fenwick Snr Can only find on record of this species for Cornwall David and it was for 3-4 miles offshore. Going to have to keep my eyes open if it is this species.

David Kipling Really? Common as muck up here (albeit Skomer is more sediment-rich and T lineata seems to thrive here). Let me have a look to see whether it's in my Cornish albums, perhaps it doesn't like the clear water down with you ...

Becky Hitchin Stop bragging! :P

David Kipling That's why it's a MNR ;) Biodiversity hotspot!

Terry Griffiths And a few around Torquay.

Bernard Picton Great photo David Kipling! I've never seen T. lineata spawn but it is a good match. They are not normally found on shore in my experience so altogether some interesting observations in this thread.

Liz Morris Hello - Please could someone confirm whether these are Sarcodictyon catenatum, or small Alcyonium digitiatum polyps. I'm pretty sure they're Sarcodictyon, but always good to double check as they're not often spotted around north Wales. Thanks :)

Sarah Bowen I'd say Sarcodictyon - did anyone see Tritonia lineata on the same dives? We've seen a fair few in Pembrokeshire and it's very likely that they're the food source of Tritonia!

Liz Morris Oh right - loads of T.lineata. It goes through stages of abundance here every year, in lots of sites where I've never seen Sarcodictyon, so I'll ask people to keep their eyes peeled a bit more - they're probably more common than I think then. Thanks Sarah Bowen.

David Kipling How can you tell the difference if you can't see the stolon and the sheath that wraps round the base of the polyps? Here's it's too silty to see that bit of the animal. It also has the feel of coming out at different angles from a small lump - which could be Sarcodictyon growing over a lump, or a baby Alcyonium base. What other clues can we use to distinguish?

Liz Morris Thanks David. Next time I will try a standard waft! If you squint a little you can almost see a pinkish base under the bottom centre polyp! I'm pretty sure there was no white blob base though, as it was growing in a very small crevice. Will look harder next time. I think Lin recorded it up here last time she was up, so will guess for Sarcodictyon based on habitat. Will clean it up next time though :)

David Kipling Yes, I noticed that little pink hint as well. Get wafting!

Kirstie Harris I also found this one, which I don't think we get in Devon. You can see how small it is compared to the cup coral on the left.

Tamsyn MAnn I've only ever seen 1 in Devon... but I know others have seen them here too...

João Pedro Silva Tritonia lineata

Terry Griffiths Loads in the right place Kirstie Harris

Kirstie Harris I'm obviously looking on the wrong places! He's a lovely nudi.

Keith Hiscock Lots of them today at Smallmouth, N. Devon. And three years ago, same place, same date.

Kirstie Harris I feel like I've been swimming around with my eyes closed all this time!

Arne Kuilman We've got smaller nudi's (-: such as Palio nothus. Great find, I am still looking for a Tritonia

David Kipling I was about to say "these are quite common in Pembrokeshire in silty habitats" but then I saw where you recorded this from!

Kirstie Harris The site was certainly very silty :)

David Kipling Which site?

Kirstie Harris The Dead Eye Wreck at Skomer.

Erling Svensen When diving at the Tritonia lineata, the wall have some species that I never have seen any other place. It looks like some kind of sea anemonies, but the grow in a kind of chain (left on the picture). Almost all the pictures from this location I can see this strange animal. Does anybody know what this specie may be?

Wilfried Bay-Nouailhat I think it's the stolon of Sarcodictyon rosea

Erling Svensen I have asked my good friend in Bergen, Torleiv Brattegard, and he agrees with you, Wilfried. Thanks a lot. So maybe the S. rosea is the food for this tine nudy?

Bernard Picton Well done, Erling, we speculated that Tritonia lineata fed on Sarcodictyon (I think Sarcodictyon catenata and roseum are synonyms) in the nudibranch guide, mostly because it was the most likely candidate as food. This looks like good evidence. I must ask Kate Lock to look closely in Pembrokeshire where T. lineata is common but we couldn't see Sarcodictyon at the same sites.

Erling Svensen Hi again

Erling Svensen I sent your message, Bernard to Torleiv. I sent his answere to Google translater, and he said: Hello again I have looked at Worms (www.marinespecies.org) and looked at Stolonifera which now has the status of the order. There are 6 families in Stolonifera totaling 29 families so there is little to take off. I went into the family Sarcodictyon which listed eight species. The information about all species are controlled by a Dutchman - Leen van Ofwegen - a little messy specialist!. It is strange that information about the distribution given only for Sarcodictyon roseum, and it is reported from the eastern Atlantic and Mediterranean. Now S. roseum described from the Mediterranean by the German Rudolph Amandus Philippi (1808-1904) and S. catenate append tar by the Englishman Edward Forbes (1815-1854). Forbes took part in an expedition to the Mediterranean in 1841-42, and his art is described in 1847. So there is a possibility that his art can come from Britain or the Mediterranean Sea. Now I have been looking in the Oscar Carlgren (1865-1954) his book on Koraldyr (in Danish fauna vol 51, 1945), and there are mentioned only Sarcodictyon catenatum Forbes in Scandinavia and spread with the same depth as I mentioned in my previous email. Things indicate that Lopez-Gonzalez and Picton's right, and that Carlgren was a good specialist. I should probably change the information I have on my list!! best Regards Torleiv Thought this would be of any interest.

Klas Malmberg Aquatilis Very interesting but there must be more things that T. lineata feeds on? Sarcodictyon isn´t very common in Sweden but we find T.lineata on regular basis. Any more suggestions on foodhabits?

Bernard Picton Yes Klas, this is exactly what puzzles me. Tritonias all (say that and someone will think of an exception) seem to eat octocorals, but we don't have many octocoral species in our area that T. lineata could be eating. Normally they seem to be wandering about on silty rocks. I wonder if the Sarcodictyon is there, but under the silt, or beneath stones?

Kate Lock I shall collate a folder of all our T. lineata photos in Pembrokeshire and see if we can get any clues from those.

Bernard Picton OK, Kate, I had a look at my photos and made an album, "Tritonia lineata looking for next meal".

Sarah Bowen I've just added a picture to that one after a quick trawl of our Tritonia pictures from North Pembs. It's amazing what turns up on the pictures when you have a really good look! Yes, there are Sarcodictyon polyps; perhaps not in every picture but certainly recorded from every dive where a T. lineata was recorded.

David Kipling I've just added some more - again, when we see T. lineata we see Sarcodictyon. All we need now is the shot of the nudi actually eating one ...

Erling Svensen Did a dive yesterday with my brother in Stavanger (yes, its in the city itself - in the harbour). Dived down to the "hundreds" of Tritonia lineata. Got one picture with 3 nudies on - all in different size. Nice, or.... :-)

Christian Skauge Very cool picture! It seems this species is not at all uncommon, and maybe has its peak this time of the year. That would explain why its so uncommon later on. I saw the same thing with the Hero formosa.

Marta Pola Could you collect some specimens for molecular studies for me? That would be great for my research!

Erling Svensen Marta: I do not know when I will be in Stavanger at this spot for diving next time. Its 1,5 hours drive from Egersund where I live. May be my brother Rudolf will dive this spot earlier than me, so an option is to ask him about collecting some. We can keep in contact. Do you put them in alcohol or formalin?

Marta Pola alcohol, please. And pictures...It would be great. Thanks

Rudolf Svensen Maybe we will dive there within the next two weeks. How many do you need?

David Kipling Erling, do you want to start a Tritonia lineata album and post this picture in it? Other people can then post their own examples as well.

Marta Pola That would be great David. And 5 specimens will be great Rudolf. Thanks!

Rudolf Svensen Hi Marta Pola . We dived the Tritonia lineata spot today. It seem like the slugs have grown a lot since february, but still there are Tritonia lineata in all sizes. I collected 5 specimens for you, but the problem is I have no alcohol, well I have beer, but I do not think that is good for nudies ;-) so I see if I can get some tomorrow. For the time they live in a big bucket. The temperature outside is the same as in the water, so I hope they will live. So if I get the alcohol tomorrow, how do I get them to you? You can contact me on e-mail rudolf@uwphoto.no

Christian Skauge Worst case let me know Rudolf, I have a handful of small collection boxes with alcohol - I can send one :-)

Erling Svensen Rudolf - I have still 1 - 2 liters left after the 10 liter barrel bought by a fishing-boat 15 years ago for other purpose than nudies..... Bernard used some of it 3-4 years ago.

Rudolf Svensen Erling. Can you send some to Stavanger quite quck?

Sarah Bowen Following on from David's comment, there's already a small album called Tritonia lineata looking for next meal; see if you can drop them in there!

Christian Skauge Finally found one! I have been looking for the Polycera faeroensis for a long time with no luck until recently. To many of you this species is not that uncommon, but up here in Norway it is a rare sight. Oddly enough it seems to be occurring quite often in the Kristiansund area.

Torjus Haukvik Congratulations! You are not the only Norwegian looking for that one! ;)

Terry Griffiths And there you go seen so many of these not unless there mating i don't bother taking photo's.

João Pedro Silva After diving here you'll be fed up with P. faeroensis :)

João Pedro Silva (I do say to my buddies "in case you find a pretty blue nudibranch... don't bother me")

Klas Malmberg Aquatilis Congratulations!

Rob Maller Congratz indeed Christian!!

Christian Skauge Thanks guys! It is always fun to see something "new", and it doesn't happen as often as it used to... way cool :-)

Torjus Haukvik You can try to "forget" some of your sightings, then it will happen more often again..! ;p

Eric van Andel the more you dive the lesser are the special sightings.... :-)

Rob Maller @ Torjus...yes, then all of a sudden it's there!!

Christian Skauge Smart move, guys :-D

Torjus Haukvik Exactly!

Helgi Winther Olsen I know a Faroe Islander looking for this small bastard!

Christian Skauge What?? You should have them all over the place - are they not your national animal?

Helgi Winther Olsen I often wonder if they were named by the Faroes because they are so bloody difficult to find there!

Torjus Haukvik Isn't it the normal way to do it? Name it after a place where it's hard to find? ;)

Christian Skauge Polycera inyourfacia :-)

Helgi Winther Olsen Polycera Whereareyouia

David Kipling Well they're releasing European beavers back into the Welsh countryside, so we'll bring some of these to Gulen and release them in return - given you your breeding population ;) Would you like some Tritonia lineata as well? A common as muck round here!

Christian Skauge LOL :-) I would trade you a Berghia norvegica for a Cuthona caerulea though ;-)

David Kipling Which of the two do you get at Gulen?

Christian Skauge The Berghia - and except for the original discovery in 1939 this is the ONLY place it has been found ;-)

Arne Kuilman Congratulations! These are also very rare in the Netherlands. Polycera quadralineata is very prevalent over here.

Bernard Picton

Christian Skauge Nice!! This species is usually very rare in Norway, and has just been spotted a few times in recent years. We found it at last year's Nudibranch Safari as well, remember :-) How deep was this Erling? T. lineata seems to be thriving on hard bottom with no apparent food source in relatively deep water. I have seen it two times, both at around 27-28 meters depth. Good pictures too!

Bernard Picton I agree, I can never figure out what they are eating. It ought to be a soft coral, I suggested Sarcodictyon in my book.

Christian Skauge Seaslugforum also states "unknown" in regards to food. But the miniscule coral you suggest would be consistent with where I have found it both times. Since our other Tritonia sp. also feed on soft coral this seems very near-fetched :-)

João Pedro Silva Never seen it and it's not included in the most recent checklist for Iberia... but the distribution range suggests it may be also present here in Portugal.

David Kipling Loads of them in west Wales, often on silty sites in relatively shallow water (well I don't generally dive deep!). You get the impression that they are grazing on something just under the surface of the silt.

Christian Skauge Interesting observation - so different from what I have seen here in Norway :-)

David Kipling I'll dig out a small album of T. lineata pictures and see what you think.

Christian Skauge Cool, let us have a look :-)

Erling Svensen Well, I was down at 45 meters. Lots and lots of them.

Christian Skauge haha that certainly proves that this is a deep species in out parts of the wood :-)

Erling Svensen Deep sea specie?? (is that deep?) ;-)

Christian Skauge Well... deeper than most nudies then.. I know you don't think 45 m is deep :-D

Bernard Picton Tell them about the sponges on my visit - no, on second thoughts, maybe not!

Erling Svensen I will never, never tell them, Bernard, that you dived to 55 meters and would come with me back ut because there was so many, nice sponges... (never.....)

Erling Svensen ... not come with me back up......

Bernard Picton Had to take a couple of photos, I'm not as quick as you are!

Sarah Bowen Is this forum going to be an opportunity to tell tales on each other's bad diving habits then?!

Bernard Picton No! Serious matters of Sea Slug biology only! No jokes, unless they are funny personal anecdotes. We're making the rules up as we go along Sarah...

Sarah Bowen Fine by me; promise to be more constructive with posts in future and leave the village idiot ones to David!

Kate Lock Not sure about the deep water - this is one of the most common species that we find in West Wales.....and in Skomer MNR we find them at all depths...from 5m down to 30m...(don't often venture deeper)...most of the sites are moderate current and moderate wave exposure and are usually found on the slightly silty bryozoan turf. I am not convinced that they feed on a soft coral! But am open to persuasion....

Bernard Picton Skomer is the one place I know of where you can find them regularly Kate. And I agree, there is usually no sign of what they could be eating.

Bernard Picton Sarah, It is intended to be quite light-hearted... Life's too short to be that serious..

Kate Lock mmm so Skomer seems to be the most popular place for Tritonia lineata and Facelina annulicornis......both pretty scarce elsewhere ....wonder if they have anything in common?

Liz Morris Sorry Bernard, we seem to go through phases of having lots of them around here too just like Kate. Mind you, I've not seen lots for a couple of year. Possibly depending on the month I guess. I'll keep my eyes peeled!

Christian Skauge Time of year is also sometimes very important. It would seem this species is peaking now, and not in march/april as most of our northern species does. See new post on the Hero formosa.