Two new millipede species of the genus Riukiaria (Diplopoda, Polydesmida, Xystodesmidae) endemic to the Ryukyu Archipelago, Japan

We describe two new species of the millipede genus Riukiaria from two islands of the Ryukyu Archipelago: R. maculata sp. n. from Tane-ga-shima, northern Ryukyus, and R. mundyi sp. n. from Yonaguni-jima, the southwesternmost member of the Yaeyama Island Group. Both species show the simple forceps-like male gonopod structure typical for the genus, but they are readily distinguishable from other members by their unique color patterns. We have also compiled a list of species in the genus described up to now.