A new species of giant Hybopeltoceras (Ammonitina) from the Lower Tithonian of the Monte Lacerone (Sabine Apennines, Central Italy) (Carlo Sarti)

Abstract The Upper Jurassic aspidoceratoid subgenus Hybonoticeras ( Hybopeltoceras ) Oloriz is very scarcely recorded, and distributed only in the Cordillera Betica (Spain), Southern Alps (Italy) and in the Central Apennines (Italy). From lower Hybonotum Zone rocks of the Upper Bugarone Formation, in Mount Lacerone (Rieti, Sabine Apennines, Italy) is described here the new species Hybonoticeras ( Hybopeltoceras ) olorizi , based on a giant macroconch holotype. The specimen is well preserved, that allow to add new data to the original Oloriz diagnosis of the genus and shows a unique morphology making the ammonite very easy to recognise. The new species shows a set of clearly recognisable phenotypical aspects strongly affected by the “Platform Effect” ( sensu Oloriz). In the appendix I the study of calcareous nannoplankton confirm the biostratigraphic attribution. In the appendix II is proposed to integrate the "San Cataldo and Red Marble of Cottanello" Natural Monument with the Castiglione quarry, Castiglione Kimmeridgian and Tithonian ammonitiferous beds Geosites from which the described holotype.