CONICET | Buscador de Institutos y Recursos Humanos

In this contribution we present a new productive site discovered at Torre del Porticciolo fossil locality (NW Sardinia, Alghero, Italy). The site is close to the outcrop which yielded the fragmentary osteological material of the first basal synapsid from Italy, the herbivore caseid Alierasaurus ronchii, representing to date the largest known non-therapsid synapsids (6-7 m long). The new fossiliferous outcrop is about 70-80 meters from the Alierasaurus type locality, roughly at the same stratigraphic level. Given the fragmentary nature of most of the recovered bones (some found broken and totally isolated within the embedding sediments) we conduct a detailed taphonomical analysis in order to define the kind of burial, the unity of finding, and the mode of preservation. The analysis highlighted a complex taphonomical process involving a multiphase entombment: i) after death, the body remained for a short time on a floodplain surface not far from the channel levee and was rapidly buried; ii) the boneswere subject to an early diagenesis with the disappearance of collagen and permineralization; iii) a strong energetic current exhumed the remains in a later flooding event, carrying the material to a site quiet and close enough, where the new sedimentary body has been deposed, along with the bones showing breakage scattered in the sediment. This final entombment site could be envisaged as a semi-perennial pond or an oxbow lake in the frame of the meander belt system. Preliminary analysis allowed to refer the new material to a large faunivorous basal synapsid within the family Sphenacodontidae. This discovery represents the first carnivorous non-therapsids synapsid from the Permian of Italy and one of the few known from Europe.