The Cenomanian-Turonian ichthyofaunas from the Scaglia-type succession of northeastern Italy

The Cretaceous period was affected by global perturbations (e.g., the Cenomanian-Turonian Oceanic Anoxic Event), which led to widespread changes in the ocean-climate system. Primary trophic levels (e.g., calcareous and other mineralized plankton) experienced accelerated rates of speciation and extinction at or near these events. Investigating the composition of fossil ichthyofaunas is crucial to reconstruct the changes induced by these disruptions in the higher trophic levels (e.g., fish communities), whose interpretation remains elusive. The broad ecological range occupied by actinopterygians today was probably quite similar in the Cretaceous because no other vertebrate groups competed with actinopterygians in their niches at that time. Considering the range of ecosystems occupied today by actinopterygians as being representative of the paleoecology of ray- finned fishes in the Cretaceous, they form a good proxy to study how vertebrates responded to global changes during the last half of the Mesozoic. In northeastern Italy, the upper Cenomanian Bonarelli Level and the Turonian-Coniacian “lastame” (Scaglia Rossa Formation) yielded diversified and well- preserved ichthyofaunas that recorded the fish assemblage composition in the Cenomanian-Turonian interval. The aim of this thesis is the study of the composition of these poorly known Tethyan assemblages, evidencing their diversity and ecological structure and comparing them to coeval assemblages. This study will hopefully provide significant data for adding new tiles for the reconstruction of the effects of the Cretaceous climatic disruptions on the higher trophic levels in the Tethyan domain.