The genus Moitessieria in the island of Sardinia and in Italy. New data on the systematics of Moitessieria and Paladilhia (Prosobranchia: Hydrobiidae) (Studies on the Sardinian and Corsican Malacofauna, IX)

The recent discovery of the genus Moitessieria in subterranean waters of the island of Sardinia provided the opportunity to increase knowledge of the genus in Italy and to revise all the populations known to live in western Liguria (Ligurian and Maritime Alps, Italy). Shell (shape and teleoconch microsculpture) and anatomical characters have been studied in many Italian populations and compared with those of some populations of the following French species: M. simoniana (De Charpentier), M. massoti Bourguignat, M. rayi (Bourguignat), M. juvenisanguis Boeters & Gittenberger, and M. lescherae Boeters. Shell structure was also compared with the following French species: M. vitrea (Draparnaud), M. puteana Coutagne, M. rollandiana Bourguignat, and M. locardi Coutagne. The results suggest that the Ligurian populations belong to M. simoniana, and those from Sardinia are closely related to M. massoti. The latter is herein recognized as a species anatomically and conchologically well distinguished from the "M. simoniana group of forms." The anatomical study (body, genitalia and radula) of the different Moitessieria species herein considered, and of the type species of genus Paladihia (P. pleurotoma Bourguignat), provided results that do not justify the inclusion of both genera in a family, Moitessieriidae, distinct from the Hydrobiidae. Even if Moitessieria and Paladilhia differ in many details, the scheme of their genitalia is basically the same and corresponds to that in the Hydrobiidae. Moitessieriidae is consequently recognized as a junior synonym of Hydrobiidae. The presence in Sardinia of Moitessieria, a genus until now considered proper to southwestern Europe (Spain, southern France, northwestern Italy), is interpreted as additional evidence the Sardo-Corsican complex migrated from the southwestern border of Palaeo-Europe by microplate drift during the middle Tertiary.