101 Bollettino della Società Paleontologica Italiana, 46 (2-3), 2007, 101-106. Modena, 15 gennaio 2008 ISSN 0375-7633 INTRODUCTION Recent strobilopsids occur in the Americas, Southeast Asia and New Guinea. American species belong to the genus Strobilops Pilsbry, 1893 (18 species: 12 to the subgenus Strobilops s.s.; three to the subgenus Discostrobilops Pilsbry, 1928; two to the subgenus Coelostrobilops Pilsbry, 1931; one species to the subgenus Nesostrobilops Pilsbry, 1931) and occur from northern Mexico to northern South America, including the West Indies and the Galapagos. Asian and New Guinea species belong to the genera Eostrobilops Pilsbry, 1928 (7 species from Japan, Korea, China and Borneo) and Enteroplax Gude, 1899 (6-7 species from Taiwan, the Philippines, Sulawesi and New Guinea) (Pilsbry, 1927- 1934, 1948; Morrison, 1953; Solem, 1967; Miller & Christensen, 1980; Minato & Tada, 1992; Vermeulen, 1992a, b; Matsumura & Minato, 1998). Fossil species date back to the early Tertiary of Europe, doubtfully the Late Cretaceous of China, the Late Pliocene of North America and the Late Cretaceous - Early Palaeocene of South America (Baker, 1938; Bartha & Soos, 1955; Steklov, 1961, 1966; Ho & Leonard, 1961; Krumbiegel, 1962; Yen, 1969; Schlickum, 1970; Ferreira & Dos Santos Coelho, 1971; Yü & Wang, 1977; Yü et al., 1982; Yü & Zhang, 1982; Wang, 1982; Manganelli et al., 1989; Karnekamp, 2000). The most ancient European records are from the Middle Eocene of Eastern Germany, while several other species have been reported from the Late Eocene of France, England and Germany. Three different groups of species, probably corresponding to present-day Eostrobilops , Strobilops (s.s.) , and Strobilops (Discostrobilops) (Pilsbry, 1927), originated from these ancestral species and lived in various parts of Europe until the Late Pliocene (Wenz, 1915, 1919, 1932; Stworzewicz, 1999; Esu & Ciangherotti, 2004). Only two species, both assigned to Eostrobilops, have been recorded in Italy: E. patuliformis (Sacco, 1886) from the early Middle Pliocene of Piedmont and Eostrobilops aloisii Manganelli, Delle Cave & Giusti, 1989 from the early Middle Pliocene of Piedmont and Umbria and the early Late Pliocene of Umbria (Manganelli et al., 1989; Esu & Ciangherotti, 2004). New material collected in Balze di Caspreno (Tuscany) turned out to belong to two different species (E. aloisii and S. cf. romani Wenz, 1915), one of which is recorded for the first time in Italy. GEOLOGICAL SETTING The Siena Basin (Fig. 1) is one of the Neogene- Quaternary basins of the Northern Apennines, a fold- thrust chain formed during the Tertiary in response to interactions between the Adria and Corso-Sardinian microplates (Carmignani et al., 2001 and references therein). The structural origin of these basins is still Strobilopsid land snails (Gastropoda: Pulmonata, Strobilopsidae) from the late Messinian - Early Pliocene (?) of Balze di Caspreno (central Italy) Giuseppe MANGANELLI, Mauro ALDINUCCI, Enrico CAPEZZUOLI & Andrea BENOCCI G. Manganelli, Dipartimento di Scienze Ambientali, Università di Siena, Via Mattioli 4, I-53100 Siena, Italy. M. Aldinucci, Dipartimento di Scienze della Terra, Università di Siena, Via Laterina 8, I-53100 Siena, Italy. E. Capezzuoli, Dipartimento di Scienze della Terra, Università di Siena, Via Laterina 8, I-53100 Siena, Italy. A. Benocci, Dipartimento di Scienze Ambientali, Università di Siena, Via Mattioli 4, I-53100 Siena, Italy. KEY WORDS - Strobilopsids, Eostrobilops, Strobilops, Palaeontology, Neogene, Italy. ABSTRACT - Strobilopsids are a group of pupilloidean pulmonate gastropods now occurring in the Americas, Southeast Asia and New Guinea. In Europe, a rich fossil record (several species in the genera Eostrobilops and Strobilops) is reported from the Middle Eocene to the Late Pliocene, but only two species have been recorded from Italy so far: Eostrobilops patuliformis (Sacco, 1886) and E. aloisii Manganelli, Delle Cave & Giusti, 1989, found in the Pliocene of Piedmont and Umbria. Fossil strobilopsids collected in Balze di Caspreno (Tuscany) lacustrine clays turned out to belong to two different species (E. aloisii and Strobilops cf. romani Wenz, 1915) one of which is recorded for the first time in Italy. RIASSUNTO - [Strobilopsidi (Gastropoda: Pulmonata, Strobilopsidae) nel Miocene superiore - Pliocene inferiore (?) delle Balze di Caspreno (Italia centrale)] - Gli strobilopsidi, un gruppo di gasteropodi polmonati pupilloidei oggi viventi nelle Americhe, in Asia Indomalese e in Nuova Guinea, presentano una ricca documentazione fossile nel Terziario europeo (Eocene medio - Pliocene superiore), con numerose specie appartenenti a due generi distinti: Eostrobilops e Strobilops. In Italia, fino ad oggi, sono state segnalate solo due specie del genere Eostrobilops: E. patuliformis (Sacco, 1886) ed E. aloisii Manganelli, Delle Cave & Giusti, 1989, per il Pliocene del Piemonte e dell’Umbria. Lo studio del materiale riferibile agli strobilopsidi proveniente dalle argille lacustri delle Balze di Caspreno (tardo Messiniano - Pliocene basale) ha consentito di accertare, per la prima volta, anche la presenza del genere Strobilops nel Neogene italiano. Il materiale analizzato è stato, infatti, assegnato a due diverse specie: E. aloisii e S. cf. romani Wenz, 1915, quest’ultima segnalata per la prima volta nel nostro paese.