Review of the millipede genus Sellanucheza Enghoff, Golovatch & Nguyen, 2004, with descriptions of three new species from Laos and redescription of S. variata (Attems, 1953) (Diplopoda, Polydesmida, Paradoxosomatidae)

The flat-backed millipede genus Sellanucheza Enghoff, Golovatch & Nguyen, 2004 is recorded from Laos for the first time, with three new species described from limestone caves in Khammouane and Bolikhamsay provinces, northeastern Laos: Sellanucheza laotica sp. nov ., S. longispina sp. nov ., and S. ancorata sp. nov . These discoveries significantly broaden the morphological concept of the genus, necessitating an amended diagnosis to accommodate unique characters such as the presence of sternal cones on both rings 5 and 6 in S. longispina sp. nov . and a highly characteristic, anchor-shaped (trifid) solenophore tip in S. ancorata sp. nov . Sellanucheza laotica sp. nov . shows distinct troglomorphic traits, including a small and pallid body, suggesting adaptations to a strictly subterranean existence. In addition, S. variata (Attems, 1953), a poorly known congener from northern Vietnam, is redescribed and illustrated based on type material from the Naturhistorisches Museum Wien, Austria. An updated identification key to all nine accepted species of the genus is provided, with a distribution map. These findings represent a major range extension for the genus into the central Indochinese Peninsula, bridging its previously known distribution between southern China and northern Vietnam. With the addition of the above three new taxa, the documented millipede fauna of Laos is updated to comprise 98 accepted species belonging to 33 genera, 12 families, and eight orders.