The land malacofauna from Vesuvius National Park and neighbouring areas (Naples, Southern Italy): Preliminary results

The faunistic data on the recent land molluscs of Vesuvius National Park (Naples, Southern Italy) and neighbouring areas sampled during field surveys from 2005 to 2006 are reported here. The data were obtained through a careful research on museum collections and literature and were supplemented with observations from field surveys. Up to now, only 23 land snails species were known from the Vesuvius National Park through bibliographical data. The faunistic research, carried out in 25 stations of different environment typologies, allowed us to discriminate 31 species: 15 of these species are reported here for the first time for the study area. The presence of 16 species was confirmed by other field investigations. Other 19 taxa are reported in the literature, but not confirmed in our research -  Helix turriculatella O. G. Costa, 1839 (obsolete nomenclature), Trochoidea trochoides Poiret, 1789, Hygromia cinctella (Draparnaud, 1801), Campylaea planospira (Lamarck, 1822), Vitrea sp. (cf. contracta (Westerlund, 1871)), Cecilioides acicula (O. F. Müller, 1774), Cochlicella acuta (O. F. Müller, 1774), Theba pisana O. F. Müller, 1774). Another 12 taxa are highly doubtful, because of possibilities for confusion with species living in other European or Italian regions, as well as previous misidentifications (Deroceras agreste (Linnaeus, 1758), Monacha gregaria (Rossmässler, 1839), Cochlicella barbara (Linnaeus, 1758), Monachoides incarnatus (O. F. Müller, 1774),Cernuella (Cernuella) cisalpina (Rossmässler, 1837), Cernuella aradasii (Pirajno, 1842), Oxychilus cellarius (O. F. Müller, 1774), O. alliarius (J. S. Miller, 1822), Zonitoides nitidus (O.F. Müller, 1774), Hyalina pseudohydatina, Ferussacia lubrica, Aegopinella nitens (Michaud, 1831); it was impossible in these cases to refer to their current specific name.

Eobania vermiculata (O. F. Müller, 1774), Rumina decollata (Linnaeus, 1758), Papillifera papillaris (O. F. Müller, 1774) appear to be the most common species. Interesting are the records of Marmorana muralis (O.F. Müller, 1774), Helix cf. ligata (O.F. Müller, 1774) and Charpentiera gibbula gibbula (Rossmässler, 1836). Charpentieria gibbula honii (Tiberi, 1878) needs genetic investigations in order to confirm its taxonomic status.

One allochthonous species (Paralaoma servilis (Shuttleworth, 1852)) was surveyed for the first time in the study area. A Red List of Threatened Species is proposed and the species are classified according to the IUCN criteria (Version 2019-2.1). The malacofauna of Vesuvius - Somma Mountain Complex is composed by 38 land mollusc species and represents 36.2% of the total species present in Campania (about 105 species, personal data) and 12.8% of the Italian fauna (about 530 species of land molluscs extrapolated from the list of Bank (2017). It is assumed that the poor biodiversity of the Vesuvian land malacofauna can be attributed essentially to the scarcity of calcareous substrates and the absence of permanent water sources.