Early Cretaceous insects from the Dalazi Formation of the Zhixin Basin, Jilin Province, China

Zhang Hai-chun

pp. 75-103, 4 plates, in English

Abstract:

Twenty species of fossil insects are described from the Dalazi Formation in the Zhixin Basin, Jilin Province, China. They are referred to 15 families and 18 genera, among which 16 species and 5 genera are recognized as new, including Rhipidoblattina magna sp. nov., Basiblattina conformis gen. et sp. nov., Geosoma prodromum gen. et sp. nov., Yanbianella simplex gen. et sp. nov., Cristocorixa dalaziensis sp. nov., Ensicupes obstusus sp. nov., Catinius ovatus sp nov., Catinius artus sp. nov., Eodromeus viriosus sp. nov., Protorabus minisculus sp. nov., Conjunctia longa sp. nov., Geotrupoides saxosus sp. nov., Proteroscarabaeus robustus sp. nov., Umenocoleus nervosus sp. nov., Longidorsum generale gen. et sp. nov. and Ovigaster cephalotus gen. et sp. nov.

The Dalazi Entomofauna can be divided into 3 ecological groups: the terrestrial, the aquatic and the semi-aquatic groups. The insect assemblage indicates a palaeo-environment with a stagnant but not deep freshwater lake surrounded by forest. The age of the entomofauna is tentatively considered as Barremian–Aptian. By comparison, the Dalazi Entomofauna is similar to the Early Cretaceous Fossil Entomofaunas of West Mongolia and Transbaikalia, indicating that these fossil entomofaunas could be closely related.

Keywords: Fossil Entomofauna, Dalazi Formation, Zhixin Basin, Barremian–Aptian, Palaeo-environment