The migration path of Gondwanian dinosaurs toward Adria: New insights from the Cretaceous of NW Sicily (Italy)

Abstract

The increasing dinosaur record from Italy questioned classic palaeogeographic scenarios for the Central Mediterranean area and suggest the proximity of landmass areas and a geographical connection between Gondwana and Laurasia during Cretaceous times. Besides several track-sites and exceptionally-preserved specimens (e.g. Scipionyx samniticus), the Italian dinosaur record also consists of isolated bones, among which the bone fragment of a theropod discovered in north-western Sicily. The bone occurs in a shallow-water carbonate succession (i.e. Pizzo Muletta, Palermo Mountains) pertaining to the Panormide Carbonate Platform (PCP). The bone was previously ascribed to the Cenomanian, strongly supporting the hypothesis of a land bridge connecting Gondwana and Adria via PCP. More recently, new sedimentological and biostratigraphic studies on the Pizzo Muletta succession have been carried out. The obtained results allow to predate the stratigraphic position of the dinosaur bone to the late Aptian–early Albian and to assess a detailed Aptian–Cenomanian evolution of this sector of the PCP. In particular, the karstic overprint of Cenomanian rudist limestones indicate a subaerial exposure of the platform preceding its drowning during latest Cenomanian times. The new assumptions allow to extend the temporal duration of the intermittent land bridge between Gondwana and Laurasia at least from Aptian to Cenomanian times and to add further evidences of the dominant tectonic control affecting the Western Tethys during Cretaceous times.