R. rhodopus was described in 1960, based on specimens from Mengyang in the Xishuangbanna Dai Autonomous Prefecture of Yunnan, China; the holotype is in the CIB, specimen 571171. Subsequently, frogs that matched the description of R. rhodopus were also found at Chiang Mai and in the Doi Chiang Dao mountains (Thailand), Buon Luoi (Vietnam), and Arunachal Pradesh (India). The latter were described as R. namdaphaensis in 1985; however, they were not compared with R. rhodopus at that time, only with R. dulitensis.