Carapace large, 0.9-1.1 mm long, ornamented with faint concentric ridges anteriorly and ventrally, otherwise valves smooth except for conspicuous normal pores. Right valve of male somewhat produced posteroventrally. Colour of living specimens buff brown. Distal process of male copulatory appendage curved, tapering.
Sublittoral. Generally on sandy substrates, in marine and outer estuarine conditions.
This is the largest European species of Pontocythere; it has frequently been confused with others from the Mediterranean, where its name has been applied erroneously to specimens referable to P. rubra (G. W. Müller, 1894) and P. turbida (G. W. Müller, 1894) (see Athersuch, 1982a, for further discussion).
Around the coasts of Britain and NW Europe from the Skagerrak to N France.