Catriona gymnota

David Kipling And further to George and Cat's post, which of the Lacuna sp are these? Taken in Fair Isle/Orkney at the end of August. There was masses of them, all over, reducing the kelp to lacework and stumps. These seem to have somewhat less "pointy" tips to the shells than those in George's picture.

George Brown David, I see what you mean about less "pointy". Cat, what have you started!

Cat Wilding George, I always was a bit of a trouble maker ;) loving the ensuing debate though, cheers guys!

Ian Smith One way to resolve the colour of spawn question might be to collect some yellow spawn and keep it in sea water to see if it changes colour as it matures. To keep it alive, I'd suggest 4 or 5 spawn masses detatched from algae, if poss without damage, as algae goes off rapidly. Keep in half litre sea water in fridge to resemble sea temperature. You might even see the veligers hatch and swim - great under a low power stereo microscope.

Ian Smith picture of veligers of Catriona gymnota escaping from spawn mass at http://www.conchsoc.org/node/3394

David Fenwick Snr Just found what I think are three 2mm Catriona gymnota on a small sample of Tubularia larynx at Sennen Cove, Cornwall, 25.04.13, in an underboulder pool on the lowershore. Can someone confirm the species please.

Peter H van Bragt Hello David, most likely indeed C. gymnota. What's in a name, I believe the current name should be Cuthona gymnota.

David Fenwick Snr Thanks Peter, I tend to follow WoRMS and Conch. Soc. for naming things, this time they don't agree.

Ian Smith Hi Dave, glad to see the hydroid sampling is bringing in results. I'm stuck with the names loaded onto the Conch Soc website when I do descriptions. I've asked for WoRMS to be adopted, but the Society only updates periodically. To try to redress this I put a link to WoRMS under "current taxonomy" on each account. When the title names are eventually updated, it will look like the content of accounts is clinging to old names. My advice is to go with WoRMS. A rose by any name would smell so sweet.

David Fenwick Snr Will send in the record under the WoRMS name just in case it helps. More hydroids and sea mats to go through later Ian.

Bernard Picton Don't worry about the current genus name. Cuthona will be split soon. Latest sequence data suggests that Calma is a Cuthona, so that puts a family inside the genus...

Cynthia D. Trowbridge egad...as bad as sacos...

George Brown Might this be Cuthona nana? Found grazing scyphistoma polyp phase of Aurelia aurita. Pinnacles in the middle of Loch Fyne (location to be confirmed).

Terry Gosliner This looks like Flabellina salmonacea to me.

Joanne Porter Beautiful image George Brown

George Brown Thank you Terry. Checking SSF, the nudibranch does indeed have "subapical white band on cerata". I'll crop and post a close-up of the cerata.

George Brown Thank you Joanne. Are you on the next Seasearch Orkney trip? Can't wait! Was there a couple of weeks ago but it was all wide angle/fisheye stuff. Kept getting distracted finding nudibranchs!

Joanne Porter I will be on the next seasearch trip! Looking forward to seeing you there George Brown. We saw a few nudibranchs but we could have done with some help from you for identifying them.

Jim Anderson Could it be Catriona gymnota?

Marco Faasse I'm not sure which species of nudibranch this is. Anyway, Flabellina/Coryphella verrucosa is known as a predator of scyphopolyps: Hydrobiologia 355: 21â€"28, 1997. A. D. Naumov, H. Hummel, A. A. Sukhotin & J. S. Ryland (eds), Interactions and Adaptation Strategies of Marine Organisms. Abundance, feeding behaviour and nematocysts of scyphopolyps (Cnidaria) and nematocysts in their predator, the nudibranch Coryphella verrucosa (Mollusca) Carina O¨ stman

George Brown Thank you Jim and Marco. I'll be posting a close-up of the cerata later. Anything else I can do to assist id?

Jim Anderson On mature reflection I agree with Marco - Flabellina verrucosa

Paula Young Another ID....with apologies for lack of sharpness, but any help with ID for the three tiny nudibranchs munching on the Tubularia near to the Facelina. Are they 'baby' Facelina, or any possibility they could be Catriona gymnota?? Any ideas, particularly welcome from Mr Bernard Picton??

Brendan Oonk They are Cuthona gymnota.

Paula Young Thanks Brendan, I didn't even notice them until I reviewed my photos.

Bernard Picton The big one on the left is Facelina auriculata, note the markings and the lamellate rhinophores.