Late Messinian continental and Lago-Mare gastropods from the Tertiary Piedmont Basin (NW Italy)

We present the first comprehensive systematic-faunistic account on a Messinian gastropod assemblage from the Moncucco Torinese site in the Tertiary Piedmont Basin in Italy. In total, the samples yielded 53 gastropod species comprising 40 terrestrial and 13 aquatic species. The assemblage reflects a predominantly dry, rather open and stony landscape mixed with restricted wooded areas with some deadwood and leaf litter. Freshwater settings were present as well but may have been largely restricted to ephemeral puddles and ponds. The assemblage is outstanding in evolutionary aspects as it represents an example of the earliest post-evaporitic gastropod fauna, which has passed the Messinian Salinity Crisis. Indeed, the composition of the terrestrial Moncucco Torinese fauna suggests a biochronologic transition from Late Miocene to Pliocene faunas, supporting the dating based on mammals as late Turolian (MN 13). About 15% of the species have been known so far only from the European Miocene, 40% were described from the Pliocene and were unknown from older strata and about 42% are only known from the Late Messinian of Moncucco Torinese. This suggests that the Pliocene continental gastropod fauna is partly rooted in Messinian faunas, pointing to a rather low turnover at the Miocene/Pliocene boundary. In terms of biogeography, no evolutionary relation to coeval Pannonian-Pontian faunas of Lake Pannon or the Dacian Basin are documented for the Lago-Mare gastropods. Hydrocena moncuccoensis Harzhauser, Neubauer & Esu n. sp., Saccoia globosa Harzhauser, Neubauer & Esu n. sp., Acicula giuntellii Harzhauser, Neubauer & Esu n. sp., Platyla manganellii Harzhauser, Neubauer & Esu n. sp., Cochlicopa fassabortoloi Harzhauser, Neubauer & Esu n. sp., Lucilla miocaenica Harzhauser, Neubauer & Esu n. sp., and ?Helicopsis piedmontanica Harzhauser, Neubauer & Esu n. sp. are described as new species. Possible further new taxa are described in open nomenclature, because the poor preservation of the material does not allow formal species to be established.