Grouvellinus huaxiensis sp. nov. was collected from Huaxi river in an urban setting of Guiyang (Guizhou, China) in 2021. Habitus and diagnostic features of the new species are described and illustrated herein. The new discovery reflects that the water quality and ecological stability of urban rivers is not necessarily in conflict with anthropogenic activities in the surrounding, which also provides us new insights into the protection of urban freshwater ecosystems.

A new riffle beetle of the genus Zaitzevia Champion, 1923, Z. tangliangi sp. nov. from Hubei Province, China is described. Habitus and other diagnostic features of the new species are described and illustrated. Habitat information and collection data of the new species are also provided.

Two new riffle beetles of the genus Zaitzevia Champion, 1923: Z. chenzhitengi sp. nov. from Sichuan Province and Z. xiongzichuni sp. nov. from Yunnan Province are described from China. Habitus and other diagnostic features of the new species are described and illustrated. Habitat information and collection data of the new species are also provided.

Termites (Isoptera) are among the most ecologically ubiquitous of terrestrial eusocial insects and provide an attractive environment for symbionts, which have evolved numerous times independently, and in lineages as diverse as millipedes and beetles. Previous studies reported the discovery of unequivocal termitophily in mid-Cretaceous amber from northern Myanmar, providing evidence that pushed the origin of termitophily back into the Mesozoic. Here we report the discovery of two more pieces of Cretaceous amber containing individuals of the trichopseniine rove beetle Cretotrichopsenius burmiticus Cai et al., 2017 (Staphylinidae: Aleocharinae: Trichopseniini) preserved together with their potential host termites, providing further evidence regarding the association between these two insect lineages. Two new termite species and genera are described as putative hosts for C. burmiticus: Arceotermes hospitis Engel & Jiang, gen. et sp. nov. and Tanytermitalis philetaerus Engel & Cai, gen. et sp. nov. Each is included in a new family, Arceotermitidae Engel, fam. nov. (type genus: Arceotermes Engel & Jiang, gen. nov.), and Tanytermitidae Engel, fam. nov. (type genus: Tanytermes Engel et al., 2007). In order to better characterize these two families the classification of lower Isoptera and clade Xylophagodea (= Cryptocercidae + Isoptera) is emended with the following new taxa: Idanotermitinae Engel, subfam. nov.; Melqartitermitidae Engel, fam. nov.; Mylacrotermitidae Engel, fam. nov.; Krishnatermitidae Engel, fam. nov.; Cosmotermitinae Engel, subfam. nov.; Hodotermopsinae Engel, subfam. nov.; Artisoptera Engel, minord. nov.; Cryptocercaptera Engel, infraord. nov. Lower termites were remarkably diverse during the mid-Cretaceous but declined in diversity considerably by the Palaeogene. The fossil rove beetle Cretotrichopsenius Cai et al., 2017 currently provides the earliest definitive evidence of termitophily and the complex association between rove beetles and termites.

For the first time, an extant histerid genus Anapleus Horn, 1873 is described from a specimen found in mid-Cretaceous Kachin amber. Anapleus kachinensis sp. nov. Although the genus Anapleus has not been precisely defined by synapomorphies, the new species shares numerous features with extant species while differing in comparatively few external characteristics. Anapleus kachinensis represents the first record of an extant histerid genus from Cretaceous deposits and provides further evidence of the ancient origin of the genus.

The genus Grouvellinus Champion, 1923 comprises 60 described species distributed across the Oriental and Palearctic regions. Species diversity is very high in mainland China, with 28 recorded species. Here, the results of the aquatic beetle survey in Guizhou Province are presented; they began in 2021, when we collected more than 5000 specimens of riffle beetle. All specimens come from small ravine streams where inhabited submerged stones. Using morphological characters of adults such as body form and size, coloration, elytral, pronotal and ventral surface structures, and forms of male and female genitalia, five new species were discovered and are described: Grouvellinus loongsp. nov., G. buyisp. nov., G. wangmoensissp. nov., G. lihaitaoisp. nov., G. muyinlinisp. nov. The species descriptions contain illustrations of diagnostic characters and measurements of metric characters such as body length, pronotal length, pronotal width, elytral length and width, and head length and width. The females are, on average, larger and have only slight differences in external morphology compared to the males. The comparative diagnoses discuss characters of the new and already known species. The results show that the existing species diversity requires more detailed research focusing on larger areas of South China in the future.