Review of the Chinese species of the genus Coelostoma Brullé, 1835 (Coleoptera: Hydrophilidae: Sphaeridiinae).

The Chinese species of the genus Coelostoma Brullé, 1835 are revised and diagnosed. Five new species are described: Coelostoma bifidum sp. nov. (Jiangxi, Guangdong, Hong Kong), C. hajeki sp. nov. (Guangdong, Guangxi), C. hongkongense sp. nov. (Hong Kong), C. huangi sp. nov. (Guangxi, Jiangxi), and C. gentilii sp. nov. (Xizang). Coelostoma coomani Orchymont, 1932, C. orbiculare (Fabricius, 1775) and C. vividum Orchymont, 1936 are reported for the first time from China. Coelostoma sulcatum Pu, 1963, syn. nov. is synonymized with C. stultum (Walker, 1858). Additional faunistic data from China are provided for C. phallicum Orchymont, 1940, C. vagum Orchymont, 1940, C. turnai Hebauer, 2006, C. wui Orchymont, 1940, C. stultum (Walker, 1858), C. vitalisi Orchymont, 1923, C. fallaciosum Orchymont, 1936 and C. horni (Régimbart, 1920). Coelostoma fabricii (Montrouzier, 1860) is not considered as member of Chinese fauna as all previous records are dubious and no new material was found during our study. The distribution of C. horni in China is discussed in detail, with records from Hong Kong here considered dubious. An updated identification key to the Chinese species of Coelostoma is provided.