Abstract
The taxonomy of the pill millipede genus Rhopalomeris Verhoeff, 1906, which is restricted to Indochina and currently comprises six described species, is refined and updated. An integrative taxonomic approach was employed that combines morphological examination with DNA barcoding using the cytochrome c oxidase subunit I (COI) gene for species identification and delineation. The first objective was to confirm the identity of Rhopalomeriscarnifex (Pocock, 1889), a charismatic species known as the "candy pill millipede" due to its vivid coloration, based on specimens collected near the type locality in Myanmar. The second objective was to describe a new species, Rhopalomerisnigroflava Likhitrakarn, sp. nov., discovered in Linno Gu, Kayin State, Myanmar. This new species is distinguished by its small body size (5.1-9.7 mm long) and yellow body with contrasting brown to blackish markings on certain terga. In addition, the position of the telopod syncoxital lobe relative to the lateral syncoxite horns separates it from other Rhopalomeris species. The interspecific divergence between R.nigroflava Likhitrakarn, sp. nov. and other congeners ranges from 10.85% to 16.13%, based on uncorrected COI p-distances, while the intraspecific divergence was 0%-7.44%. A distribution map of and a revised identification key to all known species of Rhopalomeris are also provided.