The gastrocoptids of the Fossil Forest of Dunarobba (Central Italy). With a preliminary revision of the European Neogene nominal species of Albinula and Vertigopsis (Gastropoda Pulmonata: Gastrocoptidae)

The clay encrusting the trunks of the Middle-Late Pliocene Fossil Forest ofDunarobba (Avigliano Umbra, Perugia, Italy; sheet 130 of the geological Map of Italy) contains a rich snail fauna consisting of about twenty species, some of which are of great palaeontological and biogeographical interest. Two of these species belong to the Gastrocoptidae, a family ofpupillid snails (Gastropoda, Pulmonata) never previously fiund in Apennine Italy: Gastrocopra (Albinula) acuminata (Klein, 1846) sensu Gottschick drWenz (1916) and G. (Vertigopsis) moravica (Petrbok, 1959). In order to provide a well based classification of the Dunarobba Gastrocopta, we reexamined the nominal taxa of the species-group of Albinula and Vertigopsis described from the Palaearctic. The difficulty of tracing type material of the eastern European and Asian taxa, however limited the survey to taxa from central western Europe. Current species-level taxonomy of the fossil Palaearctic Albinula is mainly derived from Wenz's (1923) survey in the Fossilium Catalogus, but our revision suggests quite a different scenario from that proposed by Wenz. The following nominal taxa are discussed and when possible revised: Pupa acuminata Klein, 1846, Vertigo turgida Reuss, 1849, Pupa lartetii Dupuy, 1850, Vertigo quadriplicata Braun, 1851, Pupa quadridentata Klein, 1853, Pupa dupuyi Michaud, 1855, Pupa lamellidens Sandberger, 1858, Leucochilus quadriplicatum mut. suevica Boettger, 1889, Vertigo fossanense Sacco, 1885, Vertigo fossanensis var. quatuordentata Sacco, 1886, Leucochylus edlaueri Wenz, 1921, Gastrocopta acuminata wenziana Pilsbry, 1921, Gastrocopta (Albinula) rhenana Geissert, 1983. Unfortunately, we were unable to clarify the identity of the two oldest established nominal species, Pupa acuminata zWVertigo turgida. The identity of the former was therefore accepted in the sense of Gottschick & Wenz (1916) and the other is still uncertain. The study of new topotypical material and designation ofneotypes is the only way to clarify the identity of these two species. This is a necessary preliminary fir a clear definition of these species and for an approach to the phylogenetic and biogeographical history of the group. Comparison of typical or topotypical material of all European fossil nominal taxa of Vertigopsis - Gastrocopta (Vertigopsis) dehmi Schlickum a~ Strauch, 1979, Gastrocopta (Vertigopsis) magna Steklov, 1966, Gastrocopta (Vertigopsis) meijeri Schlickum, 1978, Vertigo (Vertigo) moravica Petrbok, 1959, Gastrocopta (Vertigopsis) moravica oligodonta Krolopp, 1977, except Gastrocopta (Vertigopsis) nikitini Krasnenkov, 1979, and Gastrocopta (Vertigopsis) nikitini urivica Krasnenkov, 1979, demonstrates that no substantial, dimensional or nondimensional character distinguishes V. moravica, G. meijeri, and G. dehmi from each other and from the Dunarobba specimens. Only G. moravica oligodonta, G. nikitini nikitini and G. nikitini urivica differ slightly by the absence of the infrapalatal denticle (that between the upper and the lower palatal teeth). This feature does not seem substantial enough to assign them to a distinct specific taxon. The inclusion of G. magna in Vertigopsis is problematical. G. magna is distinguished from all modern Nearctic and fossil western PalaearcticVertigopsh species by a bifid composite anguloparietal lamella and a sort of low transverse lamina in basal- infrapalatal position. As far as the biogeography and relationships of Vertigopsis are concerned four scenarios seem possible.