An international research team led by Prof. WANG Bo from the Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences (NIGPAS), together with Dr. ZHANG Qianqi from Shenyang Normal University and other collaborators, has discovered a diverse fossil insect assemblage from the Lower Jurassic Xiaomeigou Formation in Dachaidan Town, Qinghai Province. Named the Dachaidan Entomofauna, this finding provides critical insights into the evolution of Mesozoic insects on the Qinghai-Tibetan Plateau. The results have been published online in Fundamental Research, a journal supervised and sponsored by the National Natural Science Foundation of China.
The Qinghai-Tibetan Plateau, known as the “Roof of the World”, is a global hotspot for geological research. Although Cenozoic insect fossils have been relatively well documented, the evolutionary history of insects on the plateau during the Mesozoic has remained largely unknown.
The Dachaidan Entomofauna is dominated by beetles (Coleoptera, 48%), followed by cockroaches (Blattodea, 26%), stoneflies (Plecoptera, 12%), and bugs (Hemiptera, 6%). Among these, the beetles are mainly archostematans and polyphagans, with some specimens preserving exquisite microstructural details. The presence of both terrestrial insects (beetles, cockroaches, and bugs) and aquatic stoneflies (adults and nymphs) indicates that these insects inhabited a swamp environment, consistent with the coal-bearing fluvial sequences of the Xiaomeigou Formation.
The stoneflies belong to the extinct family Perlariopseidae, a key group for Jurassic–Cretaceous stratigraphic and palaeoecological correlation across Asia. Notably, the aquatic insect assemblage from Dachaidan represents a unique hypotrophic ecosystem, characterized by a detritivore-based aquatic food web, where primary production consisted largely of terrestrial organic detritus and dead benthic algae. Previously, such ecosystems were thought to be restricted to the Early Jurassic–Early Cretaceous of southern Siberia, western Mongolia, and northern Kazakhstan. The Dachaidan Entomofauna thus marks the first record of this ecosystem type in China.
Compared with other Early Jurassic entomofaunas in China, the Dachaidan assemblage exhibits distinctly different taxonomic compositions and palaeoecological features, highlighting significant regional differences among Early Jurassic insect faunas on different tectonic plates in China. This discovery provides direct evidence for reconstructing the palaeogeographic distribution of Jurassic insect assemblages and offers a new window into the evolution of terrestrial ecosystems on the Qinghai-Tibetan Plateau during the early Mesozoic. It further underscores the plateau’s immense potential as a fossil treasure trove.
The study was jointly supported by the National Natural Science Foundation of China, the Second Tibetan Plateau Scientific Expedition and Research, and the Doctoral Research Start-up Foundation of Liaoning Province.
Reference: Zhang Qianqi, Chen Jun, Li Jiahao, Xu Chunpeng, Song Zhenyu, Fang Yan, Zheng Daran, Jarzembowski E.A., Zhang Haichun, Wang Bo*. 2026. First Mesozoic entomofauna from the Qinghai-Tibetan Plateau. Fundamental Research, https://doi.org/10.1016/j.fmre.2026.04.013.
(a) Region of the Qaidam Basin (green colour), red star showing study site; (b) General geography and roads in rectangle in (A); (c, d) Outcrop at the Hongshankuangou section; (e) Lithostratigraphic column of section with sampling horizon.
Representative fossils from Dachaidan Entomofauna (a) stonefly (Plecoptera: Perlariopseidae Sinitshenkova, 1985); (b) cockroach (Blattodea: Caloblattinidae Vršanský & Ansorge, 2000); (c) beetle (Coleoptera: ZygadeniaHandlirsch, 1906); (d) cockroach (Blattodea: Caloblattinidae Vršanský & Ansorge, 2000); (e, f) beetle (Coleoptera: Zygadenia Handlirsch, 1906); (g, h) stonefly nymphs (Plecoptera).
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