Trididemnum cereum

Joanne Porter Yet another squirt, this time from Hermaness, Unst.

David Kipling That's quite a distinctive squirt Jo, especially with those very large cloacal openings on the raised portions, and the almost dripping feel to it. Certainly it seems to best-match the description Bernard has for Trididemnum cereum on Habitas. But I will defer to the experts!

Wilfried Bay-Nouailhat Hi Joanne Porter, do you have any close-up?

Joanne Porter sadly I don't although I may be able to get closer with the raw file

Bernard Picton We get this one on Rathlin and at the Maidens. I've loads of photographs but these Didemnids need a careful study and revision...

Bernard Picton http://www.facebook.com/photo.php?fbid=10151090610704682&set=o.341487989207852&type=1&theater

David Kipling That Rathlin picture does looking the spitting image of the specimens from Jo and Richard.

Paula Young Hello...help with ID needed please?? Could this be Trididemnum cereum? Kent waters near Dover, about 12 m on chalk reef. Ta v much!

Wilfried Bay-Nouailhat Hi, Could you tell us if it was in or near a harbour or marina or was it in open sea?

Paula Young It was in between two harbours - about 4 km east of one and 6km west of another, and about 1/2 km off a cliff shoreline, so not right out in open sea.

Paula Young And about 9m down rather than 12m!

David Kipling Not what I'd call T cereum no. Chris Wood has shown me a pic of a Didemnid that looks like this from a Seasearcher on the south coast ... Same pink blush and 3D appearance. No idea what it is, will be interested to see if Wilfried recognises it at all from the other side of La Manche :)

Paula Young Ta v much....at least I knew it wasn't Lissoclinum :-)

Paula Young And to give some idea of scale, it probably covered an area of about 1 square foot.

David Kipling (that's 30cm x 30cm Wilfried...)

David Kipling Was there much of this about Paula, or just the one patch?

Paula Young I only saw the one patch, and we covered quite a bit of the reef in unusually good viz. I thought it was Pachymatisma from a distance, as it looked greyish, albeit much lighter than normal, so went to have a better look and realised it wasn't that, and that it must be a squirt.

Wilfried Bay-Nouailhat Mmm, I've got pictures of a similar species from the rade de Brest and Port-Tydy (Groix Island harbour) but also in some places in open sea.. Externally, it looks like Lissoclinum perforatum but more "fleshy", with fewer and wider exhaling siphons and with a white, greyish or pinkish colour. Could this be Lissoclinum perforatum? It requires closer observation to be sure. Anyone has an opinion about that?

David Kipling I've just had a look at the pictures that James Lucey took somewhere off the S Coast ... absolute dead ringer for this, same large bulbous growth habit and pink hue, same opening shapes. I'll ask him if he can post the pics (with some location details) on here. Looks very interesting Paula!

Paula Young Should've got a sample I guess, but I'm not sure how confident I am of doing that yet...

David Kipling Well bang goes Lissoclinum youngensis until you do ;)

Paula Young I worry about hurting it...'tis an animal after all ;-)

Becky Hitchin I know wwe've seen this pinky Lissoclinum beasty around Kent before over the last few years

David Kipling Do we have sites where we could go back and get some? Be great to get some and compare with the species Wilfried is seeing.

David Kipling You don't have to worry about hurting it, Paula. Firstly they only have rudimentary CNS as adults, and you'd be taking living whole animals (zooids) which then get anaesthetised in propylene phenoxytol before going into formalin. All very tree-huggy :)

David Kipling (so for a start, it should be relatively straightforward to work out if it's a Lissoclinum versus Didemnum versus Trididemnum by looking at the zooids - that'd move us forward).

Wilfried Bay-Nouailhat To compare with yours, Rade de Brest, 4 meters

Wilfried Bay-Nouailhat another, Port Tudy, Groix, 3 meters

George Brown Great photos everyone. Can we not ID via macro photos? If so, what camera angle would be the most productive?

David Kipling From the inside showing the zooids (sadly) - so we can see numbers of rows of branchial bars and the like. The literature on didemnids focuses on internal anatomy.

George Brown Thank you David.

Rachel Shucksmith We found this seasquirt diving in Shetland last week, it was quite abundant, and had this yellow colouration. I was wondering if it was Trididemnum cereum?

Joanne Porter I also photographed this and would like to know the answer to Rachel's question!

Matt Doggett looks very much like one we found in dorset yesterday too.