Alcyonium hibernicum

Wilfried Bay-Nouailhat Hi, I can't resist to show you this photo my friend Jean-Michel Crouzet sent me yesterday, of polyps of Alcyonium hibernicum with eggs inside

Richard Yorke Seen in the Scilly Isles last May but looks like nothing I would have expected there, any ideas?

Tony Gilbert Think its Sarcodictyon sp., poss. roseum Richard.

Bernard Picton Hi Richard, definitely not Sarcodictyon. This is probably Parerythropodium coralloides, which is an exciting find for the UK, as it hasn't crossed the channel before. The only problem is that what the books call Parerythropodium coralloides is actually 3 or 4 species now. The pale pink one is Alcyonium hibernicum, (it's old name) and there are two other species on the French-Portuguese coasts. I'll post some pictures later.

Chris Wood We are revising the Seasearch Anemones and Corals Guide early in the new year and I would very much like this image to include as it seems to be a first. Richard could you send details and copy of the image at high resolution to chris@seasearch.org.uk Many thanks.

Bernard Picton I think this might be Cathy McFadden's Morphotype A2 of Alcyonium hibernicum. "Colonies of Morphotype A2 occurred at all Atlantic locations from Iles Chausey (CHA) southward, but were not found in the British Isles" "Type A2 colonies were generally red or very dark pink, with some yellow in the polyps (the "pink-4'' of Groot and Weinberg 1982). Coenenchymal sclerites were always red or a mixture of red and pink; tentacular sclerites were almost always yellow (occasionally red, and very rarely white), and sclerites in the polyps were usually red or pink, often mixed with yellow, especially in the proximal region" It might not have a name yet, but is almost certainly a distinct species.

Richard Yorke Thanks Bernard, it seems I was correct in thinking it was a bit different from the expected.

Bernard Picton I emailed Cathy and she had a recollection that someone else had also seen something like this in Scilly recently. She is going to check.

Susana Martins Probably the same... https://www.facebook.com/photo.php?fbid=4300650748368&set=o.341487989207852&type=1&theater

Richard Yorke Apparently Lin Baldock (who led the trip) contacted Cathy at the beginning of May about my picture so that we are probably talking about the same sighting.

Bernard Picton This is getting more tricky by the day! "Hi Bernard - Actually, no, it would be morph A1 (A. hibernicum), which comes in two different colors. The Irish version of A1 is usually a pale pink, but in France there are two color morphs of A1, the pale pink and a much darker pink. The A. coralloides (A2) that occurs in France is red with yellow sclerites in the polyps. For awhile we thought the dark pink A1 was possibly a hybrid between A1 and A2, but further genetic work showed that not to be the case (see another attached paper). Genetically, the light pink and dark pink forms of A1 are identical, and conform to A. hibernicum. The red A2 in France is A. coralloides. The earlier photos I got from the Scilly Isles looked more like dark pink A1 than like A2. Cheers, Cathy"

Richard Yorke As you say, trickier day by day! I am getting a bit out of my depth, but reading the Summary of general features the ones that seem to fit best are either A1 or A3 as it seems to be basically red and white, with hardly a hint of yellow, even if I play with the white balance. The lobate morphology and rock substrate would also fit but as A3 was only found in Portugal, and that seems a tremendous jump for it to make. I would agree that A1 seems the most likely. However it was not the typical UK Alcyonium hibernicum described on MarLIN as that is found only on shaded or overhanging rock surfaces and is pink. This was on a vertical surface with sun shining on it and definitely more of a red.

Bernard Picton There is something odd going on here, I've seen typical pale pink A. hibernicum in a lot of places, but never this one in the UK or Ireland. A. hibernicum has odd genetics, it seems to be not reproducing sexually, more parthenogenetically, so a clone. The starfish Asterina phylactica is supposed to be doing something similar. There is a theory that this is because they went through some sort of population bottleneck during the last ice age.

Jørn Ari Snoghøj - Lillebælt OLYMPUS DIGITAL CAMERA Copyright: Jorn Ari

Jim Anderson I would say it is not - it looks more like Flabellina browni to me

Jørn Ari But what about the red oesophagus, situated just behind the rhinophores, is clearly visible?

Robert Eriksson Look at the length of the oral tentacles,, they are about the same as the rhinohores=flabellina if much longer then Facelina! Rings and colour are not very stable traits for species discrimination!

Robert Eriksson .. blooper.. Rings on the Rhinophores (lamellae) are a stable trait though. Not sure what you mean mean rings Jorn? Coloured rings of e.g. White pigmentstions are not stable for species deduction in any species of the Flabellina or Facelina (personlopinion).

Robert Eriksson ... Mind that the oral tentacle and rhinophores are retractible and you need to Watch the animal for some time to be able to deduce it's "normal" relaxed state. I agree that it is a Flabellina, but never saw brownii as a good species - any gene-studies done on brownii?

Jørn Ari I ment lamellae

Bernard Picton Sorry, but I completely disagree with you Robert Eriksson, details of coloration are very good characters, but you have to weight them by how big and mature each individual animal is. There is considerable evidence that CO1 barcode sequences are identical in closely related species of marine invertebrates, so the DNA evidence is partly dependent on which bit of DNA you sequence. There is a lot of observing and collecting to be done yet before we have all the answers...

Lucas CerCur I agree with you Bernard Picton

Bernard Picton Oh, and I should say I've seen hundreds of Coryphella browni in the field, kept them in containers with Coryphella lineata which they were sharing their Tubularia indivisa with, watched them considering whether to mate with a C. lineata and deciding not to....

Lucas CerCur I have seen photos of Trapania lineata mating with supposed T. fusca!!!!! from southern Spain.

Bernard Picton ;-) so then we have to determine whether the offspring were fertile. Horse + Donkey = Ass.

Bernard Picton So absence of mating is evidence of separate species, if mating is possible by the species normally sharing a habitat.

Bernard Picton But cross-species mating occurs, and sometimes hybrids are even fertile. It is thought from DNA evidence that the "species" Alcyonium hibernicum is a hybrid, yet it occurs in areas where neither parent is present.

Lucas CerCur Of course.

Lucas CerCur As I told to my students, Biology is no Maths

Lucas CerCur Fortunately....

Robert Eriksson Don't be sorry, for disagreeing, Bernard Picton, these discussions are advancing our knowledge! I would like to expain myself briefly about the colouration issue. In Flabellina, the colouration of the rhinophores and the cerata is very variable, at least when looking at Nordic specimens. Some specimens have rings, some have a partial ring, some have only spots of pigment. I am only claiming these traits in adult specimens. Colouration might be stable in other species. Of course variability of genes depends on what part of the DNA you are sequencing, as you stated. Thats why you tend to use noncoding or at least more variable genes (with a "faster evolution") for deducing closely related species. I am truly confident in that we never will have all the answers...