First account on some tritorial teeth from the Upper Jurassic of Mt. Nerone pelagic carbonate platform: paleoecological implications

SIMONE FABBI; ANGELO CIPRIANI; MARCO ROMANO; PAOLO CITTON

Catania

Congreso; Congresso SGI SIMP Catania 2018; 2018

Società Geologica Italiana

By the early nineteenth century, the peiagic carbonate piatform (PCP) of Mt. Nerone in the UmbriaMarcheSabina (UMS) Domain (Umbria-Marche Apennine, Itaiy) attracted schoiars from all over Europedue to the wealth of fossil fauna preserved in a stunningiy well-exposed Mesozoic sedimentary succession.Severai geo-paleontological studies were focused on the abundant and diverse invertebrate fauna, whilecontributions dealing with Mesozoic fossii vertebrate were to date virtually lacking. Recentiy, the first materiaireferable to hybodont sharks, consisting of an articuiated crushing dentition, was described from the area andreferred to as Asteracanthus cf. A. magnus. In this contributi on, we report the first evidence of ginglymodiansactinopterygians from the Upper Jurassic of Monte Nerone. The materiai is represented by seven highiytritorial isolated teeth collected from three classic locaiities of the area (i.e. Pian del Sasso, Fosso Pisciarello,I Ranchi). The general morphology of the materiai under study allow us to tentatively refer the teeth to as?Scheenstia sp., a ginglymodian iepisosteiformes fish with a Late Jurassic (Kimmeridgian) to Early Cretaceous(Hauterivian-Barremian) distribution. The occurrence of durophagous organisms, to date represented byhybodont sharks and lepisosteiformes fishes, reveals interesting palaeoecologicai scenarios characterizing thePCP-basin system of Mt. Nerone, which were most iikeiy triggered by iarge-scale geodynamic processes. Thecomplex submarine palaeotopography, inherited by the Early Jurassic rifting phase, aroused the estabiishmentof new infaunal and epifaunal communities in relativeiy deep (up to 150 m below sea-levei) pelagic settings,opening up unexpiored trophic niches for durophagous predators. The pecuiiar geodynamic setting of the UMSDomain, consisting of predominantly interconnected structural highs and iows, and the relative evolutionof a diverse invertebrate fauna characterized by terebratuiid, ostreids, iimids, brachiopods, crustaceans andgastropods, attracted both hybodontids and durophagous ginglymodians in the Tethyan Realm, influencingtheir dispersa! during the Late Jurassic.