Chris,

Steve Trewhella has recently found a Mossy Ark (Arca imbricata Bruguière, 1789) shell in a polystyrene buoy.  It would seem this is a new species for the British Isles and is not currently on the UKSI.  Could it be added please ??  The Cherry Jewel Box Clam (Chama sarda Reeve, 1847) appears to need adding also.

Steve's comment on Facebook is shown below:

"The juvenile Ark shell we found attached to a Florida Crawfish buoy has been identified as the Mossy Ark shell, a possible new British record, its always worth digging around in the holes on Polystyrene buoys, Chama sarda was also living on the same buoy, another possible new record , still awaiting DNA results on the Hairy crab ."

Cheers,
Steve