A Middle Tithonian ammonite faunula from the historical outcrop of Monte Acuto (Cantiano, Umbro-Marchean Apennine, Italy)

The Middle Tithonian (Upper Jurassic) ammonite assemblage found in a single bank (with a total thickness of about 30 cm and subdivided in two limestone beds), from the classic Monte Acuto outcrop originally quoted in the second half of the nineteenth century, is here described. From the micritic matrix, 20 ammonite specimens were extracted, belonging to 13 species, among which one, here dubitatively ascribed to Cordubiceras, was previously devoid of a formal designation and represents the first possible record of such a genus in central Italy. The fauna is dated to the Middle Tithonian Volanense Zone of the standard Mediterranean scheme.