Research progress on rotifer mitochondrial genomes has been slow, with studies primarily focusing on the genus Brachionus and bdelloid rotifers—primarily due to the considerable challenges associated with rotifer clonal cultivation. Rotifers of the genus Asplanchna are predominantly carnivorous, and sequencing and analyzing of their mitochondrial genomes can offers valuable insights into their taxonomic position while laying a solid foundation for related phylogenetic investigations. In this study, the complete mitochondrial genome sequence of Asplanchna sp. was determined and analyzed using high-throughput sequencing. The mitochondrial genome of this Asplanchna representative consists of two circular chromosomes: mtDNA-I (16,916 bp) contains 4 protein-coding genes (PCGs: cob, atp6, nad2, nad1), 2 rRNA-coding genes (16S rRNA and 12S rRNA), and 18 tRNA-coding genes; mtDNA-II (17,982 bp) includes 8 PCGs (cox1, nad6, nad4l, nad4, nad5, cox2, cox3, nad3) and 9 tRNA-coding genes. Both mtDNA-I and mtDNA-II harbor a ~9.4 kb non-coding region (NCR) downstream of the tRNA-Lys gene, with an identical AT content of 66.85% and complete sequence identity between the two NCRs. Codon usage bias analysis revealed a distinct preference in the mitochondrial genome, with serine codon UCU being the most frequently used. Ka/Ks analysis indicated that mitochondrial PCGs are under purifying selection (negative selection) and highly conserved during evolution, consistent with their role as essential energy metabolic units. A maximum likelihood (ML) phylogenetic tree was reconstructed using 10 shared core PCGs from 26 closer related species. The results showed that Asplanchna is closely related to Brachionus but distantly related to bdelloid rotifers and acanthocephalans, which aligns with its morphological taxonomic status.

To resolve stick insect phylogeny and mitochondrial rearrangement, mitochondrial genomes were sequenced. A total of ten mitochondrial genomes, 15,808–16,608 bp in length, were successfully sequenced in this study. Gene rearrangements were observed in three samples of two species: Paragongylopus plaumanni (sample number: WSZJC6 and YNZJC5), and Cnipsomorpha erinacea. The tandem duplication–random loss (TDRL) model provides a reasonable explanation for the detected gene rearrangements. Specifically, C. erinacea exhibits a gene rearrangement pattern of 12SrRNA-CR1-trnI-CR2-trnQ-trnM. P. plaumanni (WSZJC6) displays a CR-trnM-NCR-trnI-trnQ-ND2 gene arrangement, whereas P. plaumanni (YNZJC5) displays a more complex gene arrangement: a CR-trnM-NCR1-trnI-trnQ-NCR2-ND2. In addition to identifying novel gene structures, we analyzed codon usage and base composition across the 10 mitochondrial genomes. Bayesian inference (BI) and Maximum likelihood (ML) methods were employed to infer phylogenetic trees, utilizing the PCGs_123 and PCGs_12 datasets. When the unstable taxon Stheneboea repudiosa was excluded from the analysis, the subfamilies Lonchodinae and Necrosciinae were recovered as monophyletic. However, these two groups were not supported as sister lineages. Moreover, species Achrioptera manga was found to cluster with members of the family Bacillidae, resulting in the non-monophyly of both Phasmatidae and Bacillidae. The phylogenetic analysis of the three subfamilies within Pseudophasmatidae recovered the topology ((Pseudophasmatinae) + (Obriminae + Dataminae)), consistent with previous studies. Additionally, Heteropterygidae and Pseudophasmatidae formed a sister clade, while Necrosciinae and Phasmatidae formed another. Bacillidae was positioned between these two major clades, resulting in the overall topology: (Heteropterygidae + Pseudophasmatidae) + ((Bacillidae + (Necrosciinae + Phasmatidae)).

The species of the family Plectopylidae from Zhejiang, China is revised. Five plectopylid species were reported—excluding the doubtfully distributed species Sicradiscus cutisculptus (Möllendorff, 1882)—namely Sicradiscus panpanae sp. nov., Sicradiscus cf. ishizakii (Kuroda, 1941), Sicradiscus diptychia (Möllendorff, 1885), Sinicola emoriens (Gredler, 1881) and Sinicola fimbriosa (E. v. Martens, 1875). The new species can be distinguished from its congeners based on the lamella-like ribs, the very wide umbilicus, and the extremely wide anterior lamella on the parietal wall. Sicradiscus cf. ishizakii is reported from four, Sinicola emoriens from two sites, while the new species is reported only from its type locality.

The diversity of Assimineidae in China is poorly known. Populations historically identified as Assiminea violacea Heude, 1882 are reevaluated based on extensive material from the Changjiang Estuary and Zhoushan. Morphological examination of shells, radulae, and reproductive anatomy confirms that A. violacea is a junior synonym of Assiminea grayana Fleming, 1828. Molecular analyses of a 557 bp COI fragment support this revision, with phylogenetic reconstructions revealing a well-supported monophyletic clade comprising both Chinese and European specimens. This study provides the first confirmed record of A. grayana in China and discusses its potential introduction via maritime transport. These findings resolve a long-standing taxonomic confusion and clarify the biogeographic history of the genus in the Northwest Pacific.

The pseudoscorpion family Garypidae Simon, 1879, with the genus Anchigarypus Harvey, 2020, is reported from the Chinese mainland for the first time. A new species, Anchigarypus zhoudanyangi Gao & Zhang, sp. nov., found from the coast, is described along with detailed description and illustrations. Anchigarypus japonicus (Beier, 1952), is recorded from China for the first time, extending its distribution from Japan and South Korea.

The genus Euhybus has 12 known species in China. It is newly recorded from Chongqing. Two new species are described as new to science: Euhybus brevidentatus Wu, Li & Yang, sp. nov. and E. longidentatus Wu, Li & Yang, sp. nov. An updated key to all Chinese species of Euhybus is provided.

The species Aristina dolichoptera Ozerov, 2012 has not been revisited since the genus was established, and its male was hitherto unknown. Based on specimens collected from Gansu and Qinghai, China, we identified both male and female individuals and confirmed their conspecificity using COI barcodes. The male of the genus Aristina is described for the first time at both generic and specific levels. Voucher specimens are deposited at the Natural History Museum of Shenyang University (NMSU), Shenyang, China.