A New Species of the Pill Millipede Genus Rhopalomeris Verhoeff, 1906 (Diplopoda, Glomerida) from Southern Thailand

A new species of pill millipede, Rhopalomeris sirindhornae sp. nov., is described from southern Thailand based on morphological characteristics and genetic barcoding. This species is distinguished from its congeners by light yellowish body with pale pink lateral margins on each tergum, a pair of black obtuse subtriangular patches on the dorsum, a pair of faded black dots on the lateral side of the thoracic shield, a light yellowish venter with faded light brown spots on pleurites 3–11, and a roundly triangular to spatulate syncoxital lobe of the telopod. Phylogenetic trees based on a fragment of the mitochondrial COI gene confirmed the entity of the new species and revealed a close relationship with R. carnifex and R. nigroflava. Interspecific genetic distances between R. sirindhornae sp. nov. and other Rhopalomeris species ranged from 9.97–14.36%, with the shortest distance to R. carnifex. Intraspecific genetic distances within each Rhopalomeris species ranged from 0–6.16%. A new distribution map of the presently known Rhopalomeris is also provided.