Another of those not easy to ID shells. Thanks Chris.
No interactions present.
I'm sure it's not mactra stultorum as that has a glossy outer surface
see http://www.discoverlife.org/mp/20q?search=Tapes ,
http://species-identification.org/species.php?species_group=mollusca&men... ,http://www.habitas.org.uk/marinelife/species.asp?item=W21720 ,& http://naturalhistory.museumwales.ac.uk/britishbivalves/browserecord.php...
(species-identfcn says it's more circular than T.decussata)
....you're absolutely right and now looking at this again it's not triangular enough either. I hadn't thought of foreign imports. 100% you are right thanks for your help.
I see worms says that Tapes philippinarum is not accepted anymore and that it should be Ruditapes or Venerupis philippinarum common name Manila Clam - don't know whether you want to add another ID and I will agree?
The species (new to me), was according to museumwales introduced to Poole harbour as a possible commercial fishery.Many pics in eol of it
http://eol.org/pages/401137/overview/ (as Venerupis p.), & of pullet carpet http://eol.org/pages/3060328/overview.
A fine series of very useful pictures Graham.
The name is suggested as an alternative to Ruditapes philippinarum - according to Worms (note the ID Panel names)
Those pictures in EoL seem abysmal but the purple staining in your Picture 4 may confirm Chris's clever work.
The most authoritative picture I could find is >>HERE<<(USA site). The teeth seem different too, to 'my' Pullet http://www.ispotnature.org/node/632356
These helped settle me http://bcbiodiversity.lifedesks.org/pages/20033 ("does not have a row of teeth near the ventral margins")
http://www.nobanis.org/MarineIdkey/Bivalvia/RuditapesPhilippinarum.htm ("Pallial sinus not quite half as long as shell, not confluent with pallial line")
Welsh Museum stuff is good and NBN clusters it in your area Graham
Good pics, good call!
Lat/Lng: 51.3827, 1.3279
OS grid ref: TR316701