Description of a new species of the genus Riukiaria (Diplopoda, Polydesmida, Xystodesmidae) from eastern China, with the characterization of its complete mitochondrial genome

This study describes a new millipede species of the genus Riukiaria from China: Riukiaria langyaensis sp. nov., and provides an identification key to all 19 Riukiaria species currently known from China. A systematic review was conducted on the 34 described Riukiaria species, and these species were classified into five categories based on the morphology of the male gonopod. The complete mitochondrial genome of this new species was sequenced and annotated for the first time, representing the first mitogenomic data reported for the genus Riukiaria.

The mitogenome of R. langyaensis sp. nov. is 14,954 bp in length, containing 13 protein-coding genes, 22 tRNA genes, 2 rRNA genes, and a control region, with an overall A + T content of 65.8 %. All 37 mitochondrial genes are encoded on the Heavy strand. The results help clarify the confused species relationships within Riukiaria and provide fundamental data for phylogenetic studies of Xystodesmidae.