New records of Plagyrona Gittenberger, 1977 (Gastropoda: Eupulmonata: Valloniidae) from Europe and problems about specific determination

Author(s): Talenti, Enrico; Cianfanelli, Simone; Bodon, Marco | Abstract: The genus Plagyrona Gittenberger, 1977, includes only two small species of terrestrial snail: Plagyrona angusta Holyoak and Holyoak, 2012, and Plagyrona placida (Shuttleworth, 1852). While P. angusta is known only from Portugal, P. placida has a vast but fragmented distribution: it is known from some of the Macaronesian islands (Madeira and the Canary Archipelago) and some European countries: Portugal, France (in Corsica only), Italy (including Sardinia and the Tuscan Archipelago), Albania, Greece (in the Ionian Islands only) and North Africa (Algeria). New research has led to redefine the distribution range of P. angusta, identifying new populations in Spain (Balearic Islands), continental France (Var department), southern Italy (Campania), Sardinia and Greece (Kerkyra Island) and to discover new sites of P. placida on Pantelleria island and of Plagyrona spp. in Zannone island and southern Italy. The specific determination of these and others populations by examination of recent literature from Sardinia, Campania and Calabria, was carried out on a morphometric basis, but, for some populations, the variability of the diagnostic characters and the limited number of available specimens, do not allow a precise assignment. On the other hand, the existence of two distinct species is not evident at all, at least in the Mediterranean countries.