Characterization and Phylogenetic Implications of the Complete Mitogenomes of Two Species in the Genus Zhangixalus(Anura:Rhacophoridae)

Mitochondrial genomes(mitogenomes)in frogs are essential for reconstructing the phylogenetic relationships and shedding light on the molecular evolution in these animals.However,there are only seven complete Rhacophoridae genomes that have been reported to date.In this paper,two complete mitogenomes of the Chinese whipping frog(Zhangixalus chenfui)and Emei tree frog(Z.omeimontis)were described,each of which was 20520 and 19782 bp in size,and had A+T contents of 64.26%and 63.83%.The two mitogenomes each included two non-coding control region(D-loop,CR),two ribosomal RNA genes(rRNAs),13 protein-coding genes(PCGs),and 22 transfer RNA genes(tRNAs),and it was found that the mitogenome of Z.chenfui also includes three tandem tRNAMet gene sequences.A typical clover-leaf structure was found for all tRNAs except for tRNASer1(AGN),which showed a reduced DHU arm.The putative D-loop region contains multiple types of tandem repeats regions.Both of these two mitogenomes showed similar pattern of gene rearrangement(tRNA-Ser-ND6-tRNA-Glu-Cytb-CR1-ND5-CR2-tRNA-Thr-tRNA-Leu-tRNA-Pro).Additionally,three consecutive tRNAMet genes were found for the first time in Z.chenfui,a species in the Rhacophoridae family.For all phylogenetic analyses,which were based on 13 protein-coding genes from 91 Ranoidea mitogenomes,the same phylogenetic trees were observed using either maximum likelihood or Bayesian approaches.These results suggest that the phylogenetic hypotheses for the Ranoidea(including Rhacophoridae,Mantellidae,Ranidae and Dicroglossidae)derived from these mitogenomic data could provide substantiation for the relationships of(Dicroglossidae(Ranidae,(Mantellidae,Rhacophoridae))),and support the presence of a monophyletic group in four families.Moreover,Z.omeimontis and Z.dennysi were found to cluster on the same branch,indicating that they were more closely related as a group.This group may in turn form sister groups with Z.arboreus and Z.schlegelii.However,Z.chenfui is located on the base of other species in the genera.Increased mitogenome sampling should be conducted to provide a more satisfactory resolution to the phylogeny of the Rhacophorus,Rhacophoridae,and Mantellidae.