The Middle Triassic palaeontomofauna of Monte San Giorgio with the description of Merithone laetitiae (†Permithonidae) gen. et sp. nov.

A new species of Permithonid insect, Merithone laetitiae gen. et sp. nov., has been described from the Middle Triassic palaeontomofauna of Monte San Giorgio, a UNESCO World Heritage Site and one of the world's nine main insect Fossillagerstätten. This discovery is significant as it contributes to understanding the evolutionary impact of the end-Permian mass extinction on insects. The study reviews 273 fossil insects from five localities at Monte San Giorgio, notable for their exceptional preservation, including extraordinary sizes and phosphatisation revealing fine internal details. Among these, Val Mara site VM 12 contains 248 specimens, many of which are small to medium-sized and nearly intact, preserving intricate features like setae on wings and compound eyes. These fossils represent critical first or last occurrences for their lineages, providing valuable data to calibrate phylogenomic dating analyses. This has led to the backdating of origins for several insect lineages, including Diptera and Heteroptera.

Montagna, M., Magoga, G., & Magnani, F. (2024). The Middle Triassic palaeontomofauna of Monte San Giorgio with the description of Merithone laetitiae (†Permithonidae) gen. et sp. nov. Swiss Journal of Palaeontology, 143(1). https://doi.org/10.1186/s13358-024-00317-6