Five alien achatinid land snails (Gastropoda, Eupulmonata) first reported in greenhouses of Italian botanical gardens

Plant trade and exchange for horticulture, recreation or research play a significant role in the dispersal of molluscs. Alien slugs and snails accidentally introduced into Europe have established rich communities in several countries, but although these introductions could have ecological and economic implications, mollusc xenodiversity in Italian botanical gardens, plant nurseries, and greenhouses has never been investigated. Facilities throughout the country were therefore visited between 2017 and 2023. Here the list of the achatinoidean species so far recorded from Italian greenhouses is provided, giving a short description of their diagnostic characters. The greenhouses of Trento and Padua host interesting assemblages of achatinoideans: the results of this study include the first reports of four achatinids, namely Allopeas clavulinum, Opeas hannense, Paropeas achatinaceum and Subulina octona from Italy and the first record of Geostilbia aperta from Europe. Reproductive anatomy of all species except Geostilbia aperta is illustrated in detail, integrating anatomical knowledge of this group of tiny molluscs, some of which are known mainly from their shell characters. The systematics of all the species is discussed, highlighting topics for future research (e.g., status of Allopeas mauritianum, real identity of Helix hannense, anatomy of Opeas hannense, species-level taxonomy of Subulina, systematic relationships and species-level taxonomy of Geostilbia).