Two species of the genus Platythomisus Doleschall, 1859 are studied: P.xiandao Lin & Li, sp. nov. is described based on male and female specimens from Yunnan, China, and P.octomaculatus (C. L. Koch, 1845), the type species of the genus, is redescribed based on female specimens from Singapore. Its male, also from Singapore, is described for the first time.
Keywords: African region; Oriental region; new species; taxonomy; type species.