Sarcodictyon catenatum

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!

Erling Svensen Could this specie be Sarcodictyon roseum, do you think? The C. cornucopiae have not been seen in Norway yet. How do you see the different? The picture is from 10 meters deep, Egersund harbour, and the animals is aprox. 1,5 cm high.

Bernard Picton Dr. Pablo J. Lopez-Gonzalez from Seville recently contacted me to point out that the names I've been using for these small octocorals are wrong. The correct name for Sarcodictyon roseum from the NE Atlantic is Sarcodictyon catenata and it is uncertain which Mediterranean species is Evagora roseum. I don't know if it is possible to distinguish these stoloniferous octocorals from their polyps alone. Cornularia cornucopiae is a common Mediterranean species, but the one which was found by Richard Manuel in SW England is a species of Cervera, possibly Cervera atlantica. Pablo is looking for specimens for DNA and morphological studies.

Erling Svensen I will post what Torleiv Brattegard in Bergen said about this here as well (did it in the Nudi forum). 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

Wilfried Bay-Nouailhat To complete the discussion, here are three documents. Herdmann's detailed description of S. catenatum http://www.archive.org/download/proceedingsofroy8roya/proceedingsofroy8roya.pdf an other one http://www.repository.naturalis.nl/document/44307 and finally a comparison between S. catenatum and S. rosea http://www.repository.naturalis.nl/document/149348

Bernard Picton Wilfried, thanks for your help in untangling this! Here is the 1995 paper on Cornularia and Cervera: http://www.repository.naturalis.nl/document/150498 As I read it the Sarcodictyon roseum in the 1992 paper becomes Rolandia coralloides of the 2000 paper.

George Brown I've been calling this Sarcodictyon roseum. http://www.facebook.com/groups/NE.Atlantic.nudibranchs/168495086595113/#!/photo.php?fbid=3388776130893&set=a.3388774370849.144526.1614272106&type=1&theater

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 ...

Tony Gilbert I think the growth to the left is Sarcodictyon catenatum, or another stolonic species.

Erling Svensen I am not sure if I understand right, but do not all the Alcyonium spedies start their growing like encrusting species?

David Kipling Have you got any shots side-on to the polyps? Sarcodictyon looks like Alcyonium if the latter is a very small initial bud, but the former has a sheath that extends up the side of the polyp. Looking downwards on it from here I'd say it was a baby Alcyonium but worth a look at another angle.

Tony Gilbert Sadly not David, we were about to go up - it was one of the last shots I took. I'll see if I can drill into the raw image.

Liz Morris A brilliant first day out with Seasarch today but it was definitely worth waiting for. Calm enough for Bardsey, so we did Bardsey thank you very much mr weather man! Loads of squirts and bryos, a smattering of Parazoanthus and more Sarcodictyon catenatum to shake a stick at. AND sun AND puffins. Yes puffins. Briillant. Thanks to everyone, especially Paul Turkentine.

Kate Lock yippee..... we had an awesome day too...... 8m vis on Linney Head/Crow Rock and gorgeous sunshine!!

Paul Turkentine Glad we could get there....hopefully that means a better year than last year! Liked the puffins...but where were the dolphins :(

Tony Gilbert I think its Octocorallia, but then thought again for Hydrozoa such as Hydractinia. https://www.facebook.com/media/set/?set=a.173485702785521.38902.100003722780643&type=1#!/photo.php?fbid=188368437963914&set=a.173485702785521.38902.100003722780643&type=1&theater

Bernard Picton Sarcodictyon catenatum, a creeping octocoral.

Joanne Porter Is this what I think it is?

Paula Lightfoot Think it might be called Sarcodictyon catenatum if its the UK species?

David Kipling I can't see the basal stolon (there's a little sheathe that extends a little way up the stalk in this species) but I can't imagine it's anything else. I don't think it's a small bit of dead man's finger as you'd see the base of the colony in that habitat (there's no silt to hide it). So +1 from me.