Phylogeny and biogeography of extant and extinct Fusulus (Stylommatophora: Clausiliidae)

A joint maximum parsimony analysis of extant and extinct species of the Fusulus group (Clausiliidae) based on shell characters, particularly characters of the complex closing apparatus of the aperture, is presented. It reveals that the supposedly extinct Pliocene genus Parafusulus cannot be separated from the extant genus Fusulus. The extant Fusulus approximans from the Southeastern Alps is the sister group of all other Fusulus species. The extinct Pliocene Fusulus neudeggensis from the vicinity of the Eastern Alps is sister to the group including the extinct Pliocene Fusulus latestriatus from Piedmont and the more widespread extant Fusulus interruptus. Accordingly, it is proposed to maintain the subgenus Fusulus (Erjaveciella) for F. approximans but to include the extinct Pliocene species previously classified in Parafusulus, together with the extant F. interruptus, in Fusulus (Fusulus). Thus, Parafusulus and Pliofusulus are synonymized with Fusulus (Fusulus). A biogeographic analysis revealed an origin of Fusulus in the Eastern Alps and a later dispersal towards the Western Alps. F. interruptus, like Cochlodina triloba, Ruthenica filograna and Arianta arbustorum, is a representative of a biogeographic element that originated in the Eastern Alps, spread westwards and then subsequently contracted in range.