Taxonomic revision of Cidaris echinoids (Echinodermata) with "fan-shaped" radioles from the Serravallian (Miocene) of Motta San Giovanni Formation (Calabria, Italy)

Fossil remains of fan-shaped spines Cidaris have been largely described in the literature since the 19th century. However, it is the first time that they have been found in serravalian outcrops in the vicinity of Motta San Giovanni and Musuponiti (Calabria, Southern Italy). Modern description of numerous test fragments and spines collected in the field allows classifying these remains of Cidaris in their taxonomic context. The graphic analysis of biometric measurements carried in this study made it possible to name Cidaris remiger (Ponzi, 1876) as representative of the calabrian fossils as well as the other fossils studied or known. This taxonomy facilitates the comparisons with the present-day known examples, namely Cidaris blakei (Agassiz, 1878) and helps clarify the paleo-depth of the Motta San Giovanni formation deposits at these localities.