Occurrence of the millipede genus Tonkinosoma Jeekel, 1953 in China, with the description of the first presumed troglobitic species of this genus (Diplopoda, Polydesmida, Paradoxosomatidae).

The genus Tonkinosoma Jeekel, 1953 has hitherto been known to contain only two species, both from northern Vietnam. T. flexipes Jeekel, 1953, the type species of the genus, is recorded from Guangxi, southern China, for the first time. T. tiani sp. n. , a presumed troglobite, is described from caves in Guizhou, southwestern China. A key is presented to all three species of the genus.