The most ancient roachfly (Insecta: Plecoptera, Peltoperlidae) from the Lower Cretaceous of the West Transbaikalia, Russia

The oldest paleontological find of the family Peltoperlidae, which is also the first report of a fossil peltoperlid nymph, is described herein. The new genus and species Siberiopelta bashkuevi gen. et sp. nov. is established for the nymphs from the Lower Cretaceous, Neocomian, deposits of Khasurty locality in Western Transbaikalia, Russia. The small number of the stonefly nymphal remains of Siberiopelta and their fragmental preservation suggest that they were brought to the burial site postmortem by streams. All known peltoperlids live in rivers and streams draining wooded areas and this is the most probable habitat before their remains entered the lake basin.