Mitochondrial Genomes of Two Pygmy Grasshoppers (Orthoptera: Tetrigoidea) and a Comparative Analysis of Caelifera Mitogenomes

The nearly complete mitogenomes of Bolivaritettix sikkinensis and Bolivaritettix yuanbaoshanensis were determined and compared with the mitogenomes of other 29 caeliferans. These two newly determined mitogenomes displayed the typical gene organization and composition, codon usage and AT skew of most Caelifera mitogenomes. A comparison of 31 orthopteran sequences revealed that the main causes of the differences in total length are an A+T-rich region and the length of IGS, even the rRNAs, and an AT content proportional to the value of AT-skew in the third position of PCGs. In Tetrigoidea, several tRNA were found to possess smaller TΨC or DHC loops and a number of special and conserved regions or motifs were found in tRNA genes and IGS, which may be useful as a molecular synapomorphy for this genus. ML and BI methods used in phylogenetic analysis revealed that Acridoidea species may have a close relationship with Tetrigoidea species.