Living along a Pliocene Tuscan coast: terrestrial, freshwater and marine vertebrates from La Serra quarry (Tuscany)

For centuries, the Plio-Pleistocene deposits of Tuscany (central Italy) have been the location of prime discoveries of fossil vertebrates. Though such finds have significantly contributed to international vertebrate palaeontology, many of these historical finds lack precise stratigraphic whereabouts; furthermore, correlations between continental and marine assemblages have always been difficult, thus hampering integrative palaeoecological reconstructions. Here, we provide a preliminary characterization of the vertebrate assemblage from La Serra quarry (Pisa Province, Tuscany), were the exposed Pliocene sediments are arranged into a transgressive-regressive cycle that testifies to coastal marshes, deltaic-estuarine environments, semi-protected lagoons and shoreface settings. The vertebrate assemblage from these deposits features some fifteen species of mammals, reptiles and fishes. Mammals are mostly represented by isolated remains referable both to juvenile and adult individuals of Proboscidae indet., a small-sized Cervinae, a large-sized Cervidae, and Sus cf. S. arvernensis. The proboscideans are represented by large-size vertebrae and ribs. Cervidae are documented by isolated teeth and some postcrania that resemble the late Ruscinian Cervinae. The suid is represented by a juvenile specimen, smaller than Sus strozzii and Propotamochoerus provincialis, and closer to the relatively small-size suid from the Baccinello V3 fauna. The fish remains include dental and dermal elements of Carcharhinus cf. perezi, Carcharias taurus, Carcharodon carcharias, Galeocerdo cuvier, Myliobatis sp., Dasyatidae? Indet. (including the longest tail spine ever reported from the fossil and Recent records), Sparidae indet., and Tetraodontidae indet. The turtles are represented by a cervical vertebra of Chelonioidea indet. as well as by plastral and carapacial elements of Mauremys sp. and Testudo sensu lato. By including terrestrial, freshwater, and marine forms, the vertebrate assemblage from La Serra represents an ideal scenario for providing a synoptic glimpse into a Pliocene paralic ecosystem of Tuscany, as well as for elaborating novel correlations between terrestrial, freshwater and marine vertebrate assemblages.