Canalispina iapygia gen. et sp. nov.: the last Siderolitidae (Foraminiferida) from the upper Maastrichtian of southern Italy

Siderolitid larger benthic foraminifera are widespread and abundant microfossils in high-energy shallow-water Tethyan carbonate platform facies of Campanian – Maastrichtian age. The more evolved representatives of this group, placed in the genus Siderolites, are characterized by a complex canal system and by canaliculate spines. For these characters they have been often compared to recent calcarinids. The specific name Siderolites calcitrapoides has been almost invariantly used for all Maastrichtian siderolitids with spines. In this paper we give the first accurate description of the siderolitids occurring in the Maastrichtian carbonate platform facies of the Salento Peninsula (southeastern Apulia) and of the Pachino area (southeastern Sicily). The architecture of the test of these siderolitids differs considerably from that of true S. calcitrapoides. For these morphotypes we erect the new taxon Canalispina iapygia gen. et sp. nov. The new taxon developed longer and more robust spines by changing the architecture of the canal system and by embodying the base of the spines within the chambers. Biostratigraphy and strontium isotope stratigraphy support a late Maastrichtian age for the studied material, indicating that Canalispina iapygia gen. et sp. nov., represents the last step in the evolution of siderolitids before the extinction of the group at the Cretaceous-Paleocene boundary.