Late Triassic insect fauna from Toksun, Xinjiang

Abstract

Here described and illustrated is the new fossil insect fauna, called the Toksun insect fauna from the Upper Triassic Huangshanjie Formation of Kerjie, Toksun county, Xinjiang. The specimens include 17 species, 10 of which known as new genera are classified in Blattoidea, Plecoptera, Homoptera, Heteroptera, Mecoptera and Coleoptera respectively. A feature of the fauna is characterized by numbers of beetles. Cockroaches with 3 species belong to Mesoblattinidae; many water boatmen are diverse, represented by 4 species referred to 4 genera, also with the presence of stone flies, cercopoid and scorpion flies. Most insects from the fauna are moderate-sized but with a few large forms; 9 species of them are aquatic, occupying 60% of the total fauna. In the study of the Triassic fossil insects over the world, those having been known include the Apheloscyta Assemblage of South China, the Ipswich insect fauna from the Upper Triassic of Australia, the Omineo insect fauna of Japan and the Issyk-Kul insect fauna of Russia. The author suggests that as compared with the above faunas, the Toksun insect fauma is similar to the Apheloscyta Assemblage, although there are some notable events. For instance, cockroaches are rarely recorded from the Upper Triassic of South China but they are rich in the Toksun fauna and the Heteroptera are diverse; the formations containing the Upper Trassic Apheloscyla Assemblage in South China are intercalated with marine sediments but the formations containing the Toksun fauna with continental sediments.