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Eugyra arenosa

(Alder & Hancock, 1848)


David Kipling I keep seeing these sand-encrusted unitary ascidians that I assume are Molgulids from the little "crown" around the siphon. Could these just be M. manhattensis or is it likely they are another of the numerous european Molgulids ?

Becky Hitchin what is the "official" definition of manhattensis?

Marco Faasse Here I ID'd a species like that as Molgula complanata. Sometimes it occurs in mats. I remember I've seen the larvae and looked at the rim of the siphons, but forgot which combination of literature sources I used for ID. Superficially, your species looks similar.

David Kipling I've just had a look on NBN. Very few complanata records in UK *but* there are a couple around Skomer (including a recent one done by EMU, so Ali B should have ID'd it - I'll ask her) as well as one at South Hook just up the river. So that would certainly fit ... I'll get a body next time. Thanks!

Liz Morris Hi David, We took some of these molgulids from Thorn to the squirt workshop a few years back and Kate Northern and I dissected them under the supervision of John Bishop with the Moniot key. I think we came up with two species.. M.complanata (i def have photos of dissection) and M.oculata. I also have dissection images of M.socialis looking scarily similar from Strangford loch. Its got something to do with the curve in the gut and reproductive bits, apparently. So I always stick with 'Molgula sp' since then!

Tom Kerr Looking at R H Millar's book, I would suggest M. occulta is a possibility.

Wilfried Bay-Nouailhat Hi, we dissected some Molgula occulta and they don't look like the sea squirt on your photo. Monniot's document clearly shows the difficulty to identify this species, several specimens anatomically different are described

Bernard Picton Molgula occulta and Molgula oculata are both buried completely in sediment, the first in muddy sand, the second in coarse gravel. Epiphytic on seaweed like this are Molgula citrina (green, no attached sand) and Molgula complanata from what we found back in the 1980's. I think a focus on habitat preferences might be helpful with Molgula.

David Kipling Liz Morris ... was your M. oculata from a buried specimen or stuck growing on weed?

Liz Morris The M.complanata which I've got images of are from weeds like yours. I thought we had M.oculata growing from weed too, but I will have to dig out notes. Take Bernard's advice on that because at the mo its just from memory. I can be sure of the M.complanata on weed in the Haven though. Sorry, not very useful! I;ll see if I can find the fieldbook from back then.

Bernard Picton These are big animals, 3cm across. Quite unmistakeable with that bare patch between the siphons. http://www.habitas.org.uk/marinelife/species.asp?item=ZD2580

David Kipling Well unless it happens to be Eugyra arenosa ....

Liz Morris uffa!

David Kipling We had a buried one on the NRW squirt course that we thought would be M. oculata/occulta ... turned out to be Eugyra arenosa (cue head bashing against wall in frustration). So "lumpy solitary sp." for me.

Bernard Picton You would only confuse Eugyra with Molgula occulta, not M. oculata, David. I suspect that Eugyra has no space between the siphons and that it is the one I have (wrongly) illustrated on the Habitas M. occulta page.

Wilfried Bay-Nouailhat Hi, here is for sure M. occulta : http://www.mer-littoral.org/32/photo-molgula-occulta-wb01.php But I've often seen M. occulta in coarse sand, never in mud.

Wilfried Bay-Nouailhat The external description of M. citrina by Monniot doesn't match with this species but goes perfectly with Erling Svensen's photo. https://www.facebook.com/photo.php?fbid=503931053005129&set=gm.453166558092521&type=1&theater So I think it can't be M. citrina. I saw too, a species similar to David Kipling's one in south-Brittany, area from where M. citrina is supposed to be absent. M. complanata is covered in sand, lives on all kind of substratum and is said to be common, it seems to be a good option to explore. Other proposition : M. bleizi, small size 0,8-1 cm, slightly covered in sand, living on rocks and seaweeds.

Message posted on NE Atlantic Tunicata on 30 Sep 2013
Richard Yorke My pictures from last weekends dives off the Llyn now at http://www.richardy.co.uk/LlynSept2013/index.html

Shôn Roberts There are some really great photos there Richard. I think the photo of the Crystal Sea Slug is superb. (i think thats what it is).

Shôn Roberts Do you mind if I share your album on my facebook page ?

Richard Yorke No Problem at all sharing it. It is not a crystal sea slug, that is Janolus cristatus. If you look at the Eubranchus tricolor you will see that the tips of the cerata have white tips, then an orange band then white again. Compare that with a Janolus eg. http://www.richardy.co.uk/Doune2013/content/130721_103026_E-520_large.html and you will see the difference.

Shôn Roberts Thanks Richard.

Ruth Sharratt Lovely set of pics Richard - well spotted. I've not managed to spot an octopus this year, so I'm really quite jealous.

Ruth Sharratt Plus - A great picture of the eubranchus - you can really see the detail.

David Kipling Curious to see whether you and Liz and Franki thinks the following is a bivalve or an ascidian. It seems a tad bulbous, and has six-fold (hexagonal) symmetry around the siphons - bivalves always seem to be circular siphons. http://www.richardy.co.uk/LlynSept2013/content/130929_085938_E-520_large.html

Liz Morris I think it looks like a squirt to me. Too shallow. It has frilly siphons, and is 'clean between the siphons'. Is it possible its a Molgula? It is too big for M.oculata that Bernard Picton mentioned the other day?

David Kipling The anatomy of a squirt seems to result in geometric-shaped siphons (square, hexagonal or octagonal). I've never seen bivalves with geometric siphons. The frilly bit (the molgulid 'crown') suggests a Molgula (as does the fact it's buried).

Richard Yorke OK, had discussed this already with Liz and I will now make the change :-)

Liz Morris Please note... I didnt start the online discussion :)

Bernard Picton This looks like Molgula oculata. Well done Liz!

Liz Morris Great. We'll get there eventually with these squirts!

David Kipling So is this the one that Okenia aspersa eats Bernard?

Bernard Picton No I think it eats Molgula occulta. I'm also not sure whether Okenia pulchella is a separate valid species and whether Eugyra arenosa is also on their menu.

Wendy Northway great photos Richard

Message posted on Seasearch North Wales on 02 Oct 2013
Taxonomy
Animalia (Kingdom)
  Chordata (Phylum)
    Tunicata (Subphylum)
      Ascidiacea (Class)
        Stolidobranchia (Order)
          Molgulidae (Family)
            Eugyra (Genus)
              Eugyra arenosa (Species)
Associated Species