The Late Messinian “Lago-Mare” molluscan assemblage from the Trave Horizon (Colombacci Fm) at Pietralacroce (Ancona, Central Italy).

A molluscan assemblage from the biocalcarenitic Trave Horizon (Colombacci Formation) cropping out at Pietralacroce (Ancona, Marche, Central Italy) is described. The fossil assemblage consists of several taxa of bivalves of Paratethyan affinity and gastropods, belonging to Lymnocardiinae, Dreissenidae, Hydrobiidae, Melanopsidae, and Thiaridae, characterizing the latest Messinian “Lago-Mare” biofacies. Pulmonate freshwater and terrestrial gastropods (Physidae or Lymnaeidae and Helicidae) are also recorded. The autochthonous character of the assemblage is pointed out. The palaeoecological analysis reveals oligo-mesohaline shallow-water environment strongly influenced by freshwater input. The Messinian character of the molluscan assemblage from the Trave Horizon and the similarity with the ones from other upper Messinian deposits of the Colombacci Formation, cropping out in the Romagna-Marche sector (Apennine foredeep), allows to infer a latest Messinian age for the fossiliferous Trave Horizon.