Middle Triassic radiolarian assemblages from the Monte Facito Formation (Lagonegro succession, Southern Apennines, Italy)

The Lagonegro Basin represents, since Middle Triassic, the northernmost witness of the Ionian Ocean (Finetti, 2004), the south-western branch of the Tethys, and its sedimentary record is now exposed in the Southern Apennines (southern Italy). The Monte Facito Formation radiolarian cherts represent the oldest portion of the Lagonegro succession and the oldest deep water sediments of the Lagonegro Basin, indicating pelagic condition since the Late Anisian. Six outcrops have been examined in detail: three of them are in the Cerchiara area, three others are, respectively, at Capelluzzo, Mt. Facito and Tempa di Rocca Rossa. Rich and well preserved radiolarian assemblages coming from the radiolarian cherts of the six sampled outcrops of the Monte Facito Formation. These radiolarian assemblages contain Late Anisian/Ladinian taxa. The following genera and species are referred only to Late Anisian: Anisicyrtis, Baratuna, Celluronta, Parasepsagon tetracanthus, Parasepsagon variabilis, Spongosilicarmiger posterus, Tetrapaurinella tetraedrica, Tiborella florida florida, Triassistephanidium laticorne, Triassobipedis balatonica. Some new species were previously described by Marcucci & Bertinelli (2017) and some other will be described with open nomenclature herein. The radiolarian biostratigraphy of the Monte Facito Formation has been revised after the ratification and the approval of the GSSP of the Ladinian stage at Bagolino (Italy) by the International Commission on Stratigraphy (Brack et al., 2005).