First subioblattid roachoid (Insecta: Holopandictyoptera) from the Middle Triassic of Monte San Giorgio (Switzerland)

A new species of fossilized roachoid insect, Samaroblattella valmarensis, has been identified from the Middle Triassic period at Monte San Giorgio (Switzerland), marking it as the oldest known representative of its genus. This discovery extends the temporal and geographical range of Samaroblattella and establishes a connection between species from South Africa and Kazakhstan. The fossil exhibits unique wing traits, including elongated ellipsoidal forewings with sigmoidal radial vein stems, and a hind leg morphology resembling that of extant jumping cockroaches, suggesting possible jumping behavior indicative of convergent evolution in Eoblattodea. Additionally, the elongate ovipositor differs significantly from those in crown group Dictyoptera, implying that Subioblattidae likely laid eggs in sediment or plant tissues without hardened ootheca. This study provides significant insights into the evolutionary history and behavioral adaptations of this ancient insect lineage.

Montagna, M., Magnani, F., Magoga, G., & Nel, A. (2025). First subioblattid roachoid (Insecta: Holopandictyoptera) from the Middle Triassic of Monte San Giorgio (Switzerland). Swiss Journal of Palaeontology, 144(1). https://doi.org/10.1186/s13358-025-00354-9