Four new species of Grouvellinus Champion, 1923 with very long median pronotal carina are described from China: G. hongkongensis sp. nov. (Guangdong, Guangxi, Hong Kong), G. longiusculus sp. nov. (Jiangxi), G. mediocarinatus sp. nov. (Fujian, Guangdong), and G. robustus sp. nov. (Anhui). These species are obviously closely related to G. bishopi Jäch, 1984 described from Malaysia (Selangor). The latter is here recorded for the first time from Kedah and Perak (Malaysia). Habitus photographs, detailed line drawings of the male genitalia, as well as a key to the males of the species of Grouvellinus with very long median pronotal carina are provided.
Two new species of Ancyronyx Erichson, 1847 (Coleoptera: Elmidae) are described from Borneo: A. pulcherrimus (Brunei) and A. reticulatus (Sabah). Habitus views, illustrations of important characters as well as plastron structures of Ancyronyx reticulatus are presented and discussed.
Ancyronyx lianlabangorumsp. nov. (Coleoptera, Elmidae), a new spider riffle beetle from the Kelabit Highlands (Sarawak, northern Borneo), is described. Illustrations of the habitus and diagnostic characters of the new species and the similar, polymorphic A. pulcherrimus Kodada et al. are presented. Differences to closely related species, based on COI nucleotide sequences and morphological characters, are discussed. Ancyronyx pulcherrimus is here recorded from Sarawak for the first time, based on DNA barcoding.
Ancyronyx clisterisp. nov. (Coleoptera, Elmidae) a new spider riffle beetle discovered from northern Borneo (Brunei; Sabah and Sarawak, Malaysia) and the larva of Ancyronyx sarawacensis Jäch are described. Illustrations of the habitus and diagnostic characters of the new species and the similar and highly variable A. sarawacensis are presented. Differences to closely related species, based on DNA barcodes and morphological characters, are discussed. Association of the larva and the imago of A. sarawacensis, and the occurrence of Ancyronyx procerus Jäch in Peninsular Malaysia and Sabah are confirmed by using COI mtDNA sequences.