Also consider A. crassa (G.O.Sars), A. pygmaea (G.O.Sars), A. Zchokkei (Schmeil), and - most importantly - A. Duthiei (T and A Scott) - discovered in Shetland.
The photograph here does not have enough detail to fully identify this sample.
Please note this is an amateur project. Best efforts are made to identify species. However this website should not be relied on as a reference. Assistance with identifications and taxonomy is very much welcomed — please contact us.