Review of the genus Coelostoma of Taiwan with description of a new species (Coleoptera: Hydrophilidae)

The water scavenger beetle genus Coelostoma Brullé, 1835 of Taiwan is reviewed based on freshly collected material and museum specimens. Seven species are recognized, of which one new species, Coelostoma (Lachnocoelostoma) taiwanense sp. nov., is described. Distributional data of C. fallaciosum Orchymont, 1936 and C. stultum (Walker, 1858) are summarized. Coelostoma phallicum Orchymont, 1940, C. wui Orchymont, 1940, C. vitalisi Orchymont, 1923 and C. bhutanicum Jayaswal, 1972 are reported for the first time from Taiwan. Coelostoma vagum Orchymont, 1940 is excluded from Taiwanese fauna pending the rediscovery of vouchers or newly collected specimens. A distribution map and key to Taiwanese species of the genus are provided