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Terebratulina retusa

(Linnaeus, 1758)

Ruth Sharratt There area few small beige coloured bivalves (there were lots on the wall). I thought possibly baby scallops of some sort, but you can see one that is open and the feeding inlets remind me of mussels rather than the typical scallop fringe. Also, when closed there were relatively long tentacles? outside the shell. So, any ideas? They were found at about 20m in the sound of Mull on a boulder wall.

George Brown Ruth, I think they are Brachiopods, Terebratulina retusa. I think I can see an open one in the middle of the picture.

Ruth Sharratt Thanks - I should have recognised them. They were taken with a wide angle lens so that was the best pic I could get.

Message posted on Seasearch Identifications on 06 Nov 2013
George Brown This brachiopod, Terebratulina retusa, about 10mm across, is covered in sponge. Is there a species of sponge linked to T. retusa in this way? Ardnoe Point, Sound of Jura, about 20m. Many thanks.

Andrew Want Excellent! - Terbratulina is very important in Palaeontology...

George Brown Can I bring this back up to the top in the hope that someone can suggest a name for the sponge on this brachiopod? Please?

Sarah Bowen It looks a bit like Hymedesmia coriaceum, which Jennifer Jones recently ID'd for me on a kelp stipe in Pembrokeshire. Possibility?

Bernard Picton With that big exhalant canal it could be Spanioplon armaturum.

Bernard Picton We often get Iophon nigricans on brachiopods off the west coast of Ireland. It is a nice bright yellow. I suspect that the sponges prefer a calcareous substratum and perhaps they also benefit from the feeding current of the brachiopods.

Claire Goodwin That's interesting Sarah Bowen - I thought it could be Hymedesmia brondstedi/coriacea (there is another taxonomic mix-up with these) but as Bernard says it is also Spanioplon like in appearance.

George Brown Many thanks everyone! I see what you mean and again, no straightforward identification. Can I please send you guys a sample?

Message posted on NE Atlantic Porifera on 15 May 2013
David Kipling For Inga and Erling ... from Orkney.

David Kipling For Inga Williamson. We still don't know what this is so any ideas very welcome!

Andy Horton Possible: Terebratulina retusa (Terebratulina retusa) Norw.: Armføtting This marine animal, with a diameter of 33 mm and two shells looks very much like a mussel at the first sight. However, this species belongs within the genus of Brachiopods and is a living fossil that is common along wide parts of the European Atlantic coast from the Mediterranean to Northern Norway and usually in at least 30 metres deep water on hard bottom. http://www.tauchprojekt.de/fauna/diverses.htm

Marco Faasse Can't see the photo David, can you make it public or make friends? I've seen Retusa in Loch Fyne and the Sound of Kerrera, so one would expect it on the Orkneys as well ...

David Kipling Can you see it now Marco Faasse?

Inga Williamson It's "mollusc-like" but no idea what. I think it's an individual organism, rather than something being eaten. The tentacles look like they belong to it. What a delicate lovely little thing.

Inga Williamson And thanks for letting us see, David!

Animalia (Kingdom)
  Brachiopoda (Phylum)
    Rhynchonelliformea (Subphylum)
      Rhynchonellata (Class)
        Terebratulida (Order)
          Terebratulidina (Suborder)
            Cancellothyroidea (Superfamily)
              Cancellothyrididae (Family)
                Cancellothyridinae (Subfamily)
                  Terebratulina (Genus)
                    Terebratulina retusa (Species)
Associated Species