Giulia TONIATO, Stefano MARABINI, Benedetto SALA, Gian Battista VAI
Improvements in the knowledge of Middle to Late Pleistocene terrestrial stratigraphy in the Romagna and Emilia Apennine foothills and new studies on the underlying marine yellow sand deposits have led to reconsider the taxonomy of a fossil bison neurocranium found in the “Sabbie gialle” layers of the Salita di Oriolo quarry, near Faenza in the late 1980s. The skull fragment, erroneously associated in the past with a southern mammoth (Mammuthus meridionalis) skull found in the same large quarry some distance away from it, was identified as Bison aff. schoetensacki. Reanalysis of morphometric traits and comparison with other fossil material questions this interpretation and suggests a re-positioning of the Oriolo bison among the primitive Bison (Eobison) forms of the Late Villafranchian, before the end of the Early Pleistocene. To test the consistency of the new assignment, an updated review of all available regional and local stratigraphic data is here presented. Original and new field data are focused in view of a more precise dating of the top layers of the marine Blue Clay (Argille Azzurre) Fm underlying the “Sabbie gialle” (Yellow sand) and of a closer correlation of the different cyclic sand bodies. The outcome is that the bison skull was dug about 25 m below the Mammuthus meridionalis, and both mammals were buried into different depositional cycles separated by unconformities. While the mammoth remain was emplaced sometimes after the Matuyama/Brunhes reversal and may therefore be assigned to the Middle Pleistocene, the bison is definitely older, and might actually be correlated with a late Early Pleistocene Sicilian age not far from the Jaramillo subchron, which is the present target of field research.
late Lower and Middle Pleistocene, marine biostratigraphy, large mammals, cyclostratigraphy, magnetostratigraphy.