Els Moitessieriidae (Gastropoda: Rissooidea) de Les Deus de Sant Quintí de Mediona (l'Alt Penedès, Catalunya, Espanya); descripció de Moitessieria dexteri sp. nov.

The moitessieriids from Les Deus of Sant Quintí de Mediona (l’Alt Penedès, Catalonia, Spain) are described on the basis of conchological material. Two different species are distinguished, being attributed to Moitessieria servaini and Moitessieria dexteri sp. nov. The new species displays the last whorl of the shell detached from the rest of the spire. This feature makes the attribution to the genus Moitessieria debatable, because this character is present in the genus Sorholia, in which it is nevertheless much more developed. The lack of operculate material does not enable confirming whether M. dexteri displays the internal prominence of the operculum that further characterizes the type species of this other genus, Sorholia lescherae, endemic from France. In any case, the numerous differences of the new species relative to S. lescherae suggest that these taxa are not closely related. Regarding M. servaini from Les Deus, it is smaller than other populations of this species, but displays the same shell proportions as a sample of M. servaini from the Gaià River at Santa Perpètua de Gaià. In contrast, the specimens from Les Dous of Torrelles de Foix, previously also attributed to M. servaini, display a more robust shell; until a more detailed revision of this species is performed, they are here attributed to M. aff. servaini