Krisna species are insects that have piercing–sucking mouthparts and belong to the Krisnini tribe in the Iassinae subfamily of leafhoppers in the Cicadellidae family. In this study, we sequenced and compared the mitochondrial genomes (mitogenomes) of four Krisna species. The results showed that all four mitogenomes were composed of cyclic double-stranded molecules and contained 13 protein-coding genes (PCGs) and 22 and 2 genes coding for tRNAs and rRNAs, respectively. Those mitogenomes exhibited similar base composition, gene size, and codon usage patterns for the protein-coding genes. The analysis of the nonsynonymous substitution rate (Ka)/synonymous substitution rate (Ks) showed that evolution occurred the fastest in ND4 and the slowest in COI. 13 PCGs that underwent purification selection were suitable for studying phylogenetic relationships within Krisna. ND2, ND6, and ATP6 had highly variable nucleotide diversity, whereas COI and ND1 exhibited the lowest diversity. Genes or gene regions with high nucleotide diversity can provide potential marker candidates for population genetics and species delimitation in Krisna. Analyses of parity and neutral plots showed that both natural selection and mutation pressure affected the codon usage bias. In the phylogenetic analysis, all subfamilies were restored to a monophyletic group; the Krisnini tribe is monophyletic, and the Krisna genus is paraphyletic. Our study provides novel insights into the significance of the background nucleotide composition and codon usage patterns in the CDSs of the 13 mitochondrial PCGs of the Krisna genome, which could enable the identification of a different gene organization and may be used for accurate phylogenetic analysis of Krisna species.

This study describes a new species of Polyxenida from China, Lophoturus sineprocessussp. nov., along with a species newly recorded from China: Eudigraphis nigricans (Miyosi, 1947), and provides additional descriptions of Eudigraphis sinensis Ishii & Liang, 1990 and Polyxenus hangzhoensis Ishii & Liang, 1990. The study conducted mitochondrial cytochrome c oxidase subunit I (COI) sequencing for all four species and constructed a phylogenetic tree based on the molecular data. The comprehensive morphological descriptions and molecular analyses confirm the addition of one new species and one newly recorded species for the Polyxenida fauna of China, elevating the total number of known Polyxenida species in the country from 10 to 12. The study also includes an identification key for Polyxenida species in China.

Due to the limitations of taxon sampling and differences in results from the available data, the phylogenetic relationships of the Myriapoda remain contentious. Therefore, we try to reconstruct and analyze the phylogenetic relationships within the Myriapoda by examining mitochondrial genomes (the mitogenome). In this study, typical circular mitogenomes of Mecistocephalus marmoratus and Scolopendra subspinipes were sequenced by Sanger sequencing; they were 15,279 bp and 14,637 bp in length, respectively, and a control region and 37 typical mitochondrial genes were annotated in the sequences. The results showed that all 13 PCGs started with ATN codons and ended with TAR codons or a single T; what is interesting is that the gene orders of M. marmoratus have been extensively rearranged compared with most Myriapoda. Thus, we propose a simple duplication/loss model to explain the extensively rearranged genes of M. marmoratus, hoping to provide insights into mitogenome rearrangement events in Myriapoda. In addition, our mitogenomic phylogenetic analyses showed that the main myriapod groups are monophyletic and supported the combination of the Pauropoda and Diplopoda to form the Dignatha. Within the Chilopoda, we suggest that Scutigeromorpha is a sister group to the Lithobiomorpha, Geophilomorpha, and Scolopendromorpha. We also identified a close relationship between the Lithobiomorpha and Geophilomorpha. The results also indicate that the mitogenome can be used as an effective mechanism to understand the phylogenetic relationships within Myriapoda.

The nominate subgenus Pediopsoides (Pediopsoides) Matsumura, 1912 is widely distributed in the Oriental region but has high species diversity only in southern China. The present paper describes and illustrates six new species of Pediopsoides (Pediopsoides) namely, P. (P.) ailaoshanensis Li & Dai, sp. nov., P. (P.) quadrispinosus Li & Dai, sp. nov., P. (P.) flavus Li & Dai, sp. nov., and P. (P.) pianmaensis Li & Dai, sp. nov. all collected in Yunnan Province, southwestern China, P. (P.) maoershanensis Li & Dai, sp. nov., found in Guangxi Autonomous Region, southern China, and P. (P.) huangi Li & Dai sp. nov., from Taiwan, previously incorrectly recorded as a new name by Li & Dai, 2018 in Dai et al. 2018: 203 for P. (P.) femorata Huang & Viraktamath, 1993 (nec Pediopsis femorata Hamilton, 1980). Two new junior synonyms of Sispocnis Anufriev, 1967 are proposed, i.e., Digitalis Liu & Zhang, 2002, syn. nov. and Neosispocnis Dmitriev, 2020, syn. nov.