Two new species of Oriental Copelatus Erichson, 1832, with additional records of the genus from China (Coleoptera: Dytiscidae: Copelatinae)

Two new Oriental species of the diving beetle genus Copelatus Erichson, 1832 are described and illustrated: Copelatus liwu sp. nov. from Hainan, China, and C. nakai sp. nov. from Laos. Both species are characterised with relatively slender habitus, orange basal transverse band on elytra, elytral striation consisting of six discal and one submarginal striae (members of C. irinus species group), but predominantly with the distinctive shape of male genitalia. New records from China are provided for the following species: Copelatus dentatipenis Jiang, Hjek & Jia, 2022 from Hubei and Shaanxi, C. japonicus Sharp, 1884 from Hubei, and C. tenebrosus Rgimbart, 1880 from Hong Kong.