Revision of the javanicus species group of the millipede genus Glyphiulus Gervais, 1847, with descriptions of five new species from China (Diplopoda, Spirostreptida, Cambalopsidae)

The javanicus-group of Glyphiulus is re-assessed and its Chinese component species are presently divided between the following two newly-circumscribed species groups, i.e. the formosus- and the sinensis-group. The two can be differentiated, based on the diagnostic characters of the first pair of legs in the male. In addition, metatergal crests being complete and the carinotaxy formula on the collum being I–III+P+M are only characteristic of the formosus-group. A molecular phylogeny of the genus, based on DNA sequencing of four gene fragments of four genes, allows for Glyphiulus to be recovered as a monophyletic group, the phylogenetic relationship being ((Clade A, Clade B), Clade C). Molecular evidence is fully congruent with the morphological one. In addition, based on barcoding data, interspecific p-distances between Glyphiulus species amount to 11.2–24.9%, vs. 0–8.2% for intraspecific p-distances. Five new species of Glyphiulus, all cavernicolous, are described from China: G. sinuatoprocessus Zhao & Liu, sp. nov., G. conuliformis Zhao & Liu, sp. nov. (both from Guangdong Province), G. xiniudong Zhao & Liu, sp. nov., G. scutatus Zhao & Liu, sp. nov. and G. portaliformis Zhao & Liu, sp. nov. (all three from Guangxi Zhuang Autonomous Region). The known Chinese species of the formosus-group appear to mainly be confined to the South China region.