The redescription and complete mitogenomes of two Oxycarenus species (Hemiptera, Oxycarenidae) and phylogenetic implications.

In this study, the two Oxycarenidae species, O.gossypii Horváth, 1926 and Oxycarenusbicolorheraldus Distant, 1904, are redescribed, and their complete mitogenomes are sequenced and analyzed. The phylogeny of Lygaeoidea is examined using 45 complete mitogenomes of lygaeoid species and four outgroup species. The gene orientation and arrangement of the two mitogenomes are found to be consistent with typical Lygaeoidea mitochondrial features, comprising 37 genes, including 13 PCGs, 22 tRNAs, 2 rRNAs, and a control region. Nucleotide composition of the species was biased towards A and T, with the gene order identical to the putative ancestral arrangement of insects. Start codons, stop codons, RNAs, relative synonymous codon usage (RSCU), and nucleotide diversity (Pi) of Oxycarenidae exhibited characteristics similar to other families in Lygaeoidea. Bayesian-inference (BI) and maximum-likelihood (ML) methods were employed to investigate phylogenetic relationships using PCG datasets from selected species. Phylogenetic analyses reveal slightly different topologies between BI and ML methods, with variation primarily concentrated in Colobathristidae and Rhyparochromidae. Our study confirms that the two sequenced Oxycarenidae species formed a single clade, and the position of Oxycarenidae remains stable in both ML and BI phylogenetic trees. These findings expand the mitochondrial genome databases of Lygaeoidea and provide valuable insights into the phylogenetic relationships within Lygaeoidea or Pentatomomorpha.