On the polytypic and problematic Clausilia dubia: notes on its nomenclature and systematics (Gastropoda, Pulmonata, Clausiliidae)

The nomenclature of some subspecies of Clausilia dubia is changed on the basis of type material studied and the synonymy is revised accordingly. The subspecies generally known as C. d. obsoleta should be called C. d. dubia instead. The name C. d. vindobonensis has to be used for the taxon usually considered the nominate subspecies by recent authors. An alpine subspecies, C. d. alpicola, is preliminary re-described and figured. Altitudinal variation as known from the Austrian eastern Alps, but differing in various aspects, is described for populations of C. dubia from the Val di Funes (Villnösstal) in the southeastern Alps of Italy.