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Modiolarca subpicta

(Cantraine, 1835)


Paula Lightfoot Is this Musculus subpictus? 2.5mm long from Strangford.

Ian Smith Yes, it's a well marked Musculus/ Modiola/ Modiolarca/ Modiolus/ Mytilus tumida/ subpicta/ subpictus/ marmoratus - just too many changes in my lifetime :-(

Simon Taylor Hi Paula. Did you ever check that Strangford specimen which looked like a juvenile discors?

Paula Lightfoot thanks Ian glad you mentioned the confusion of names, I was looking for records on the Gateway and couldn't find any - I only looked for Modiolarca subpicta and Musculus subpictus, I see there are a few others I should check! Simon I think this photo is discors, 8mm would that make it a juvenile?

Paula Lightfoot and the other side

Simon Taylor Hmmm, actually the shape of that looks more like subpicta than discors. And I think the specimen I recall was smaller than 8mm. Have you counted the ribs on this one? Shape can be a little confusing in subadult specimens.

Ian Smith I agree with Simon, this is subpictus/a , but at 8mm it is a fully functioning adult. Here's a picture of one 2mm long expelling ova I THINK; perhaps they have strange pooh. I can't find any text saying it has fertilization in the mantle cavity and expels ova in clumps; can anyone help with a link to an accessible online text giving details that I don't have to pay £30 to view?

Paula Lightfoot I only have three specimens (2.5mm, 6.5mm and 8mm) and looking at them together under the microscope they all look VERY similar - so probably all subpictus. I will post a photo of all three and try to count the ribs but I'm busy at work this week and away to Scotland at the weekend, but I will come back to these little shells eventually...

Message posted on British Marine Mollusca on 07 Sep 2013
Paul Semmens Erring towards Jorunna tomentosa for this though would like others' more informed opinions.

David Fenwick Snr Looks like the sea squirt Corella eumyota to me Paul; it appears to have siphons at the top and to the right, half way down.

David Fenwick Snr Jorunna have just started appearing at Chimney Rocks, Penzance in the past couple of weeks so there's every chance of seeing them down there http://www.aphotomarine.com/sea_slug_jorunna_tomentosa.html

Paul Semmens Thanks Dave

David Fenwick Snr Paul my guess is that the brown animal embedded into the squirt is probably the bivalve mollusc Marbled Crenella, Modiolarca subpicta syn. M. tumida. I've removed a few molluscs from sea squirts recently and to check at home, they've all been this species.

Taxonomy
Animalia (Kingdom)
  Mollusca (Phylum)
    Bivalvia (Class)
      Pteriomorphia (Subclass)
        Mytiloida (Order)
          Mytiloidea (Superfamily)
            Mytilidae (Family)
              Modiolarca (Genus)
                Modiolarca subpicta (Species)
Associated Species