First Emilian Record of the boreal-affinity bivalve Portlandia impressa Perri, 1975 from Montefiore dell'Aso (Marche, Italy)

We report the first record of the bivalve Portlandia impressa from Pleistocene sediments of Marche. The finding is represented by a few shells retrieved from inner shelf deposits exposed at Grotti, in the municipality of Montefiore dell'Aso (Ascoli Piceno). The sediments that yielded the fossils belong to the upper part of the Marchean Quaternary marine sequence (Qm), here referred to the Early Pleistocene. In particular, the integration among foraminifer, calcareous nannoplankton, and mollusk data supports an Emilian age for the fossiliferous level. This record extends the chronostratigraphical range of the Early Pleistocene boreal affinity species P. impressa, traditionally retained Santernian in age. From the paleoecological point of view, the comparison among the very few mollusk assemblages containing P. impressa enables us to retain this fossil protobranch as a tolerant pelophilous taxon that inhabited inner-shelf soupy bottoms.