The First Complete Mitochondrial Genome of the Genus Pachycondyla (Formicidae, Ponerinae) and Insights into the Phylogeny of Ants

Ants are the standout group among eusocial insects in terms of their exceptional species richness and ecological dominance. The phylogenetic relationships among the group remain elusive. Mitochondrial genome sequences, as a kind of molecular marker, have been widely utilized in the phylogenetic analysis of insects. However, the number of ant mitogenomes published is still very limited. In this study, we utilized next-generation sequencing to determine the complete mitogenome of Pachycondyla annamita (Formicidae, Ponerinae). This is the first mitogenome from the genus Pachycondyla. Two gene rearrangements were identified in the mitogenome, the transposition of trnQ and trnM and the transposition of trnV and rrnS. The secondary structures of tRNAs were predicted. The tRNA genes trnR and trnS1 lacked the dihydrouridine (DHU) arm, and the trnE lacked the T?C (T) arm. Phylogenetic analyses of the mitochondrial protein-coding genes under maximum likelihood (ML) and Bayesian inference (BI) criteria resulted in conflicting hypotheses. BI analysis using amino acid data with the site-heterogeneous mixture model produced a tree topology congruent with previous studies. The Formicidae was subdivided into two main clades, namely the poneroid clade and the formicoid clade. A sister group relationship between Myrmicinae and Formicinae was recovered within the formicoid clade.

Automated summary

This study determined the complete mitogenome of Pachycondyla annamita and identified two gene rearrangements. The secondary structures of tRNAs were predicted. Phylogenetic analyses of mitochondrial protein-coding genes resulted in conflicting hypotheses, but a congruent tree topology was obtained using a site-heterogeneous mixture model. This study provides important information for understanding the phylogenetic relationships of ants.