Palaeontological study of Middle Oxfordian-Early Kimmeridgian (Late Jurassic) ammonites from the Rosso Ammonitico of Monte Inici (north-western Sicily, Italy)

This paper deals with the palaeontological study of ammonites collected in strata of Middle Oxfordian-Lower Kimmeridgian pro parte Rosso Ammonitico of two sections of Monte Inici (western Sicily, Italy), namely Monte Inici East and Castello Inici. The complete faunal list of ammonites collected in the Middle Oxfordian-Lower Kimmeridgian fossiliferous beds of Monte Inici succession is here presented for the first time. Thirty-two species have been described in the palaeontological study. As a result, the formerly published biozonation of the two successions exposed at Monte Inici has been refined. The biostratigraphical dating of the onset in the middle Oxfordian of both the radiolarite sedimentation at Castello Inici and the nodular facies of the Rosso Ammonitico at Monte Inici East is not coeval, as tentatively suggested in previous papers. On the basis of the vertical distribution of the species of the genus Gregoryceras Spath, 1924 the onset of cherry limestones in section Castello Inici slightly predates the onset of Rosso Ammonitico nodular facies observed in section Monte Inici East.