The genus Otostigmus Porat, 1876 is reviewed based on recent material collected from parts of Vietnam. A total of nine species are documented and imaged. The phylogeny of the genus Otostigmus is analyzed based on a 603-bp dataset of the cytochrome c oxidase subunit I (COI) gene. The average K2P genetic distance between Otostigmus species is 19%, and eight of nine species are considered to be monophyletic, except O. amballae. The phylogenetic relationship between Otostigmus species necessitates a deeper study with more samples and genetic data. In addition, an identification key to all Otostigmus species is provided for the fauna of Vietnam.
Keywords: Myriapoda, Biodiversity, taxonomy, COI, phylogeny, Vietnam.