Aciculid land snails (Gastropoda: Caenogastropoda, Cyclophoroidea) from the Zanclean (early Pliocene) of Balze di Caspreno (central Italy)

Five species of aciculids are reported herein from the Zanclean (early Pliocene) of Baize di Caspreno (Tuscany, central Italy): one belongs to the genus Acicula Hartmann, 1821, three to Platyla Moquin-Tandon, 1856 and one to Renea Nevill, 1880. Statistical analysis (PCA and RDA) was performed on ten shell variables to test the taxonomic assignment of four of the taxa, in order to compare them with relevant recent species. Caspreno Acicula differs from similar taxa by virtue of its more evident external peristomal varix, smaller size and lower HID ratio; RDA confirmed its distinction from other congeners: it is therefore assigned to a new species: Acicula kadolskyi n. sp. The largest taxon, Caspreno Platyla, represented by only a few very fragmentary shells, is tentatively assigned to P. dupuyi (Paladilhe, 1868) by virtue of shell size and shape and structure of the external peristomal varix. The other two taxa of Caspreno Platyla are assigned to P. gracilis (Clessin, 1877) and P. similis (Reinhardt, 1880); RDA confirmed that no significant statistical difference exists between recent and fossil populations of the two species. Caspreno Renea, represented by only very fragmentary shells, is tentatively identified as R. veneta (Pirona, 1865) due to its conical shape and dense ribbing. This conclusion is not supported by RDA, possibly due to the fragmentary state of the material which made it impossible to measure some important shell variables. Apart from A. kadolskyi n. sp., the other species are still extant. Two of these (P. gracilis and R. cf veneta) are reported for the first time as fossils and the other two (P. cf dupuyi and P. similis)for the first time from the Pliocene of central Italy, although one of them (P. cf dupuyi) had previously been recorded from the Fossil Forest of Dunarobba, based on misidentified material of P. similis