The malacological record from the Piànico-Sèllere basin (Northern Italy).

Non-marine molluscs, Palaeoecology, Piànico-Sèllere Basin, Northern Italy

The occurrence of the genus Tanousia Servain (Hydrobiidae) in the Middle Pleistocene Piànico-Sèllere Basin (Bergamo, N Italy): palaeoclimatical and chronostratigraphical meaning.

The occurrence of the freshwater genus Tanousia Servain 1881 (Hydrobiidae) in the Middle Pleistocene lacustrine succession of the Pia` nico-Se` llere Basin (Bergamo, Northern Italy) represents a significant biostratigraphical discovery. The Tanousia were recovered from the basal part of the carbonate varved bed (BVC), in siltysandy slump sediments, and from the lower and middle parts of the La Palazzina Member (MLP) of the Pia` nico formation. The BVC unit, in which a dated tephra layer occurs, accumulated during an interglacial phase, as shown by pollen analyses. The MLP Tanousia-bearing layers have been laid down during cool–temperate climate oscillation. The Pia` nico population of Tanousia displays great morphological variability but is similar to T. runtoniana (Sandberger, 1880), T. stenostoma (Nordmann, 1901) and T. cf. T. stenostoma (Nordmann, 1901), from the Bavelian and Cromerian interglacial deposits of late Early and early Middle Pleistocene age in Northern Europe. As for these species, the Tanousia population from Pia` nico appears to indicate fluvial conditions under a fully temperate climate

Variation in shell morphology in the fossil freshwater gastropod Tanousia subovata (SETTEPASSI 1965) from the Mercure Basin (Middle Pleistocene, southern Italy): Distinct taxa or ecophenotypic variation? (Gastropoda Prosobranchia: Hydrobiidae)

The study of the shell plasticity of the extinct Hydrobiidae Tanousia subovata (SETTEPASSI 1965) resulted in a better understanding of the relationships between the shape of the organisms and the environment that influenced their life. Three populations, from distinct sections of the lacustrine Middle Pleistocene Mercure Basin (Basilicata-Calabria, southern Italy), have been investigated, using a landmark-based geometric morphometric analysis to quantify the morphological variability. Morphometric data and data coming from independent proxies (such as lithology and other fossils), already published on the studied basin, have been taken into account. Results have been interpreted to discriminate between internal and external factors influencing the shape of the shell. The geometric morphometric method proved useful to reveal some morphological variations between the three populations, which, following the comparisons with palaeoenvironmental data and with the literature appear to result from ecological or maybe chronological factors rather than indicating distinct species

Note Illustrative della Carta Geologica d'Italia alla scala 1:50.000, Foglio 082 Asiago

Descrizione della geologia dell'area di Asiag

Mercury deposition in Western Tethys during the Carnian Pluvial Episode (Late Triassic)

The Late Triassic Carnian Pluvial Episode (CPE) was a time of biological turnover and environmental perturbations. Within the CPE interval, C-isotope and sedimentary records indicate multiple pulses of depleted carbon into the atmosphere–ocean system linked to discrete enhancements of the hydrological cycle. Data suggest a similar cascade of events to other extinctions, including being potentially driven by emplacement of a large igneous province (LIP). The age of the Wrangellia LIP overlaps that of the CPE, but a direct link between volcanism and the pulsed CPE remains elusive. We present sedimentary Hg concentrations from Western Tethys successions to investigate volcanic activity through the previously established CPE global negative C-isotope excursions (NCIEs). Higher Hg concentrations and Hg/TOC are recorded just before and during NCIEs and siliciclastic inputs. The depositional settings suggest volcanic Hg inputs into the basins over the NCIEs rather than increases of Hg drawdown or riverine transport. Differences in Hg and Hg/TOC signals between the basins might be linked to coeval LIP style or the temporal resolution of the sedimentary successions. Overall, our new data provide support for a link between pulses of Wrangellia LIP volcanism, NCIEs, and humid phases that mark the CPE in the Western Tethys