The First Complete Mitochondrial Genome Sequence of and (Amphibia: Anura: Dicroglossidae), with Related Phylogenetic Analyses

Members of the genus (family Dicroglossidae) are often referred to as excellent model species with which to study amphibian adaptations to extreme environments and also as excellent keystone taxa for providing insights into the evolution of the Dicroglossidae. However, a complete mitochondrial genome is currently only available for . Thus, we analyzed the complete mitochondrial genomes of and to investigate their evolutionary relationships within and their phylogenetic position in the family Dicroglossidae. Our results showed that the genomes of (17,837 bp) and (18,373 bp) encode 13 protein-coding genes (PCGs), two ribosomal RNA genes, 23 transfer RNA (tRNA) genes, and a noncoding control region. Overall sequences and genome structure of the two species showed high degree of similarity with , although the motif structures and repeat sequences of the putative control region showed clear differences among these three species. In addition, a tandem repeat of the tRNA-Met gene was found located between the tRNA-Gln and ND2 genes. On both the 5' and 3'-sides, the control region possessed distinct repeat regions; however, the CSB-2 motif was not found in . Based on the nucleotide sequences of 13 PCGs, our phylogenetic analyses, using Bayesian inference and maximum-likelihood methods, illustrate the taxonomic status of with robust support showing that and are more closely related than they are to . In conclusion, our analyses provide a more robust and reliable perspective on the evolutionary history of Dicroglossidae than earlier analyses, which used only a single species ().