The phylogeny of Orthoptera inferred from mtDNA and description of Elimaea cheni (Tettigoniidae: Phaneropterinae) mitogenome

The complete 15,831 bp nucleotide sequence of the mitochondrial genome from Elimaea cheni (Phaneropterinae) was determined. The putative initiation codon for cox1 was TTA. The phylogeny of Orthoptera based on different mtDNA datasets were analyzed with maximum likelihood (ML) and Bayesian inference (BI). When all 37 genes (mtDNA) were analyzed simultaneously, the monophyly of Caelifera and Ensifera were recovered in the context of our taxon sampling. The phylogeny of Orthoptera was largely consistent with previous phylogenetic hypotheses. Rhaphidophoridae to be a sister group of Tettigoniidae, and the relationships among four subfamilies of Tettigoniidae were (Phaneropterinae + (Conocephalinae + (Bradyporinae + Tettigoniinae))). Pyrgomorphidae was the most basal group of Caelifera. The relationships among six acridid subfamilies were (Oedipodinae + (Acridinae + (Gomphocerinae + (Oxyinae + (Calliptaminae + Cyrtacanthacridinae))). However, we did not recover a monophyletic Grylloidea. Myrmecophilidae clustered into one clade with Gryllotalpidae instead of with Gryllidae. ML and BI analyses of all protein coding genes (using all nucleotide sequence data or excluding the third codon position, and amino acid sequences) revealed a topology identical to that of the entire mtDNA genome dataset. However, 22 tRNAs genes excluding the DHU loop and TψC loop (TRNA), and two rRNA genes (RRNA) perform poorly when analyzed as single dataset. Our results suggest that the best phylogenetic inferences were ML and BI methods based on total mtDNA. Excluding tRNA genes, rRNA genes and the third codon position of protein coding genes from dataset and converting nucleotide sequences to amino acid sequences do not positively affect phylogenetic reconstruction.