A new species of Laccobius Erichson, 1837 (Hydrophilidae, Coleoptera) from the Chinese Himalaya, with comments on taxonomic status of subgenera Glyptolaccobius Gentili, 1989 and Cyclolaccobius Gentili, 1991 and additional faunistic records from China

Abstract. A new species of the water scavenger beetle, Laccobius (Glyptolaccobius) motuoensissp. nov., is described from Motuo County, Xizang, China and its diagnostic characters are illustrated. Examination of this new species and re-examination of previously described species revealed that the separation of the subgenus Glyptolaccobius Gentili, 1989 and Cyclolaccobius Gentili, 1991 is artificial: both subgenera are hence combined here. Cyclolaccobiussyn. nov. is synonymized with Glyptolaccobius, and the latter is shown to be diagnosed by 7-segmented antennae as a unique synapomorphy. All species treated until now under Cyclolaccobius are here transferred to Glyptolaccobius, with the only exception of L. hingstoni Orchymont, 1926, L. jumlanus Gentili, 2015 and L. zugmayeri Knisch, 1910 which are tentatively transferred to the subgenus Hydroxenus Wollaston, 1867, as their antennae bear eight antennomeres. Three species are recorded for the first time from China: L. (Microlaccobius) orientalis Knisch, 1924 from Xizang, Laccobius (M.) exilis Gentili,1974 from Xinjiang, and Laccobius (M.) sublaevis J. Sahlberg, 1900 from Xinjiang. Additional faunistic data from China are provided for the following species: L. (Microlaccobius) hammondi Gentili, 1984, Laccobius (M.) formosus Gentili, 1979, Laccobius (Hydroxenus) hingstoni d’Orchymont, 1926, Laccobius (Glyptolaccobius) yunnanensis Gentili, 2003, Laccobius (Compsolaccobius) decorus (Gyllenhal, 1827), Laccobius (Dimorpholaccobius) bipunctatus (Fabricius, 1775), Laccobius (D.) striatulus (Fabricius, 1775), Laccobius (s. str.) bedeli Sharp, 1884, L. (s. str.) binotatus d’Orchymont, 1934, Laccobius (s. str.) cinereus Motschulsky, 1860, and Laccobius (s. str.) minutus (Linnaeus, 1758).