Phasianidae is a family of Galliformes containing 38 genera and approximately 138 species, which is grouped into two tribes based on their morphological features, the Pheasants and Partridges. Several studies have attempted to reconstruct the phylogenetic relationships of the Phasianidae, but many questions still remain unaddressed, such as the taxonomic status and phylogenetic relationships among Crossoptilon species. The mitochondrial genome (mitogenome) has been extensively used to infer avian genetic diversification with reasonable resolution. Here, we sequenced the entire mitogenomes of three Crossoptilon species (C. harmani, C. mantchuricum and C. crossoptilon) to investigate their evolutionary relationship among Crossoptilon species. The complete mitogenomes of C. harmani, C. mantchuricum and C. crossoptilon are 16682 bp, 16690 bp and 16680 bp in length, respectively, encoding a standard set of 13 protein-coding genes, 2 ribosomal RNA genes, 22 transfer RNA genes, and a putative control region. C. auritum and C. mantchuricum are more closely related genetically, whereas C. harmani is more closely related to C. crossoptilon. Crossoptilon has a closer relationship with Lophura, and the following phylogenetic relationship was reconstructed: ((Crossoptilon + Lophura) + (Phasianus + Chrysolophus)). The divergence time between the clades C. harmani-C. crossoptilon and C. mantchuricum-C. auritum is consistent with the uplift of the Tibetan Plateau during the Tertiary Pliocene. The Ka/Ks analysis showed that atp8 gene in the Crossoptilon likely experienced a strong selective pressure in adaptation to the plateau environment. C. auritum with C. mantchuricum and C. harmani with C. crossoptilon form two pairs of sister groups. The genetic distance between C. harmani and C. crossoptilon is far less than the interspecific distance and is close to the intraspecific distance of Crossoptilon, indicating that C. harmani is much more closely related to C. crossoptilon. Our mito-phylogenomic analysis supports the monophyly of Crossoptilon and its closer relationship with Lophura. The uplift of Tibetan Plateau is suggested to impact the divergence between C. harmani-C. crossoptilon clade and C. mantchuricum-C. auritum clade during the Tertiary Pliocene. Atp8 gene in the Crossoptilon species might have experienced a strong selective pressure for adaptation to the plateau environment.

The genera Teredorus and Systolederus belong to Tetriginae and Metrodorinae respectively. However, species within these two genera have strikingly similar features, made it difficult to identify clearly by morphological characteristics. In this study, we sequenced the mitochondrial genomes (mitogenomes) of two Teredorus species, and compared them with Systolederus mitochondrial sequences. The sequenced mitogenomes of T. hainanensis and T. bashanensis are 14,946 bp and 14,775 bp in size, respectively. The A+T content of mitogenomes is 76.2% (T. hainanensis) and 74.0% (T. bashanensis). Comparative analysis showed that mitochondrial sequences and structure were similar within these two genera. The results of K2P distances and phylogenetic analysis revealed that Systolederus and Teredorus might be likely considered as one genus of Teredorus. It will provide important resources for further understanding of the taxonomy and phylogenetic relationship of Systolederus and Teredorus.

The mitochondrial genome (mitogenome) has been widely used to infer the phylogeny, origin and evolution of insects. Although mitogenomic data have been used to study the phylogenetic relationships of Tetrigoidea (Orthoptera), larger sample sizes were also essential to explore the detailed phylogenetic relationships of these taxa. In this study, two complete mitogenomic sequences were sequenced from Phaesticus moniliantennatus (formerly Flatocerus daqingshanensis and F. nankunshanensis). The mitogenome sequences were assembled, annotated and analyzed. The length of the mitogenomes was 16,147 and 16,224 bp, and the nucleotide composition was A>T>C>G, A-skew and C-skew. Large intergenic regions between trnS(ucn) and ND1 were identified with a length of 191–233 bp. Phylogenetic analyses showed that Batrachideinae formed the basal position of Tetrigoidea, followed by Tripetalocerinae. The monophyly of several subfamilies was not supported. Within Tetriginae, P. moniliantennatus clustered with a clade containing Systolederus spicupennis, S. hainanensis and S. zhengi (Metrodorinae), indicating their closer phylogenetic relationship. The divergence time results indicated that Batrachideinae diverged at 170.96 Ma and Tripetalocerinae diverged at 149.36 Ma. And the divergence time between P. moniliantennatus and the closely related Systolederus clade was 87.06 Ma. These results represent the available mitogenome sequences of the genus Phaesticus and provide a valuable data resource for reconstructing phylogenetic relationships and studying the differentiation of Tetrigoidea species.

The genus Motacilla belongs to Motacillidae (Passeriformes), where mitochondrial features are poorly understood and phylogeny is controversial. Whole mitochondrial genome (mitogenome) data and large taxon sampling are considered to be ideal strategies to obtain this information. We generated four complete mitogenomes of M. flava, M. cinerea, M. alba and Dendronanthus indicus, and made comparative analyses of Motacilla species combined with mitogenome data from GenBank, and then reconstructed phylogenetic trees based on 37 mitochondrial genes. The mitogenomes of four mitogenome sequences exhibited the same gene order observed in most Passeriformes species. Comparative analyses were performed among all six sampled Motacilla mitogenomes. The complete mitogenomes showed A-skew and C-skew. Most protein-coding genes (PCGs) start with an ATG codon and terminate with a TAA codon. The secondary structures of RNAs were similar among Motacilla and Dendronanthus. All tRNAs except for trnS(agy) could be folded into classic clover-leaf structures. Three domains and several conserved boxes were detected. Phylogenetic analysis of 90 mitogenomes of Passeriformes using maximum likelihood (ML) and Bayesian inference (BI) revealed that Motacilla was a monophyletic group. Among Motacilla species, M. flava and M. tschutschensis showed closer relationships, and M. cinerea was located in a basal position within Motacilla. These data provide important information for better understanding the mitogenomic characteristics and phylogeny of Motacilla.

To gain a better understanding of mitogenome features and phylogenetic relationships in Sylvioidea, a superfamily of Passerida, suborder Passeri, Passeriformes, the whole mitogenome of Alaudala cheleensis Swinhoe (Alaudidae) was sequenced, a comparative mitogenomic analysis of 18 Sylvioidea species was carried out, and finally, a phylogeny was reconstructed based on the mitochondrial dataset. Gene order of the A. cheleensis mitogenome was similar to that of other Sylvioidea species, including the gene rearrangement of cytb-trnT-CR1-trnP-nad6-trnE-remnant CR2-trnF-rrnS. There was slightly higher A+T content than that of G+C in the mitogenome, with an obvious C skew. The ATG codon initiated all protein-coding genes, while six terminating codons were used. The secondary structure of rrnS contained three domains and 47 helices, whereas rrnL included six domains and 60 helices. All tRNAs could be folded into a classic clover-leaf secondary structure except for trnS (AGY). The CR1 could be divided into three domains, including several conserved boxes (C-string, F, E, D, C and B-box, Bird similarity box, CSB1). Comparative analyses within Sylvioidea mitogenomes showed that most mitochondrial features were consistent with that of the A. cheleensis mitogenome. The basal position of the Alaudidae within the Sylvioidea in our phylogenetic analyses is consistent with other recent studies.

The pygmy grasshopper, Tetrix japonica, is a common insect widely distributed in eastern Asia. To further investigate its genome characteristics, high-throughput sequencing was used to obtain genome survey data based on Illumina platforms. Analysis of the results showed that the genome size of T. japonica was 1.51 Gb based on K-mer analysis (K-mer = 23), while the size inferred by the flow cytometry (FCM) was 1.94 Gb. The percentage of repetitive sequence was 51.7%, with LINE being the most abundant element (15.46%) and SINE the least abundant element (0.19%). The genome size of T. japonica was relatively smaller compared to other orthopteran species, suggesting a fewer repetitive sequences. These genome survey data can be useful for genetic analysis and phylogenetic evolution of T. japonica and have potential utility in genomic and biological studies of orthopteran species.