A review of the Asian species of the Cercyon unipunctatus group (Coleoptera: Hydrophilidae: Sphaeridiinae)

Asian species of the Cercyon unipunctatus species group are reviewed. Nine species are recognized in Asia, three of which are described as new: C. flavimarginatus sp. nov. and C. kubani sp. nov. from Yunnan province of China, and C. undulipennis sp. nov. from Sichuan and Yunnan provinces in China. Besides these, the species group contains the following Asian species: C. divisus Hebauer, 2002 (newly recorded from northern India and China), C. quisquilius (Linnaeus, 1761) (newly recorded from Kyrgyzstan, Turkmenistan, Syria and Iran), C. unipunctatus (Linnaeus, 1758), C. unipustulatus Nakane, 1982 and C. verus Shatrovskiy, 1989. All species are (re)described, illustrated and a summary of the known distribution is provided. An identification key to the Asian species of C. unipunctatus group is provided, and the species are also briefly diagnosed from similar Palaearctic and Oriental Cercyon species.