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| Riukiaria langyaensis Han & Wang, in Han, Liu, Wang et Dong, 2026. |
Abstract
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.
Key words: Complete mitochondrial genome, identification key, millipede, mitogenome, Riukiaria, species description, taxonomy
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| Riukiaria langyaensis sp. nov. A. Live coloration; B. Live specimen under UV light. |
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| Riukiaria langyaensis sp. nov. A. Posterior part of body, dorsal view; B. Midbody rings, dorsal view; C. Anterior part of body, dorsal view; D. Telson, ventral view; E. Both gonopods, ventral view; F. Rings 16–19 and telson, dorsal view. Scale bars: 1.0 mm. |
Riukiaria langyaensis Han & Wang, sp. nov.
Diagnosis. This species closely resembles Riukiaria mundyi Korsós, Nakamura & Tanabe, 2011 in tergal features and body coloration. However, Riukiaria langyaensis sp. nov. differs by having a lighter body color than R. mundyi, with antennae and walking legs exhibiting a wheat-colored hue and the paratergal margins appearing translucent. In terms of gonopod structure, the prefemorite of Riukiaria langyaensis sp. nov. is similar to that of Riukiaria contigua (Wang, 1957), but its acropodite is more inflated and nearly spherical, with an indistinctly forked tip, and the prefemoral processes are completely missing.
Zewu Han, Xin Liu, Jiajia Wang and Yan Dong. 2026. Description of A New Species of the Genus Riukiaria (Diplopoda, Polydesmida, Xystodesmidae) from eastern China, with the characterization of its complete mitochondrial genome. ZooKeys. 1272: 315-335. DOI: doi.org/10.3897/zookeys.1272.182977 [10 Mar 2026]
