Middle Triassic Nautilida from the Besano Formation of Monte San Giorgio, Switzerland

A rare discovery of Middle Triassic nautilids from the Besano Formation at Monte San Giorgio, Switzerland, sheds light on these cephalopods' presence in an unusual anoxic intra-platform basin environment. The study documents five specimens, including three well-preserved taxa: Enoploceras rieberi sp. nov., Germanonautilus aff. ellipticus, and Syringonautilus sp. indet., representing the families Tainoceratidae and Syringonautilidae. Notably, this is the first record of Enoploceras in the Middle Triassic, expanding its known distribution. The findings challenge the notion that nautilids were restricted to pelagic environments, as they were found in sediments typically deposited under anoxic conditions. This research contributes to our understanding of nautilid diversity and paleoecology during a critical period in Earth's history.

Pieroni, V. (2022). Middle Triassic Nautilida from the Besano Formation of Monte San Giorgio, Switzerland. Swiss Journal of Palaeontology, 141(1). https://doi.org/10.1186/s13358-022-00263-1