Characterization of the complete mitochondrial genome of an endemic species in China, Aulocera merlina (Lepidoptera: Nymphalidae: Satyrinae) and phylogenetic analysis within Satyrinae.

Abstract

The mitochondrial genome (mitogenome) has been extensively used as molecular markers in determining the insect phylogenetic relationships. In order to resolve the relationships among tribes and subtribes of Satyrinae at the mitochondrial genomic level, we obtained the complete mitogenome of Aulocera merlina (Oberthür, 1890) (Lepidoptera: Nymphalidae: Satyrinae) with a size of 15,259 bp. The mitogenome consisted of 37 typical genes, including 13 protein-coding genes (PCGs), 2 ribosomal RNA genes (rRNAs), 22 transfer RNA genes (tRNAs), and an A + T-rich region. The gene organization and arrangement were similar to those of all other known Satyrinae mitogenomes. All PCGs were initiated with the canonical codon pattern ATN, except for the cox1 gene, which used an atypical CGA codon. Nine PCGs used the complete stop codon TAA, while the remaining PCGs (cox1, cox2, nad4, and nad5) were terminated with a single T nucleotide. The canonical cloverleaf secondary structures were found in all tRNAs, except for trnS1 which lacked a dihydrouridine arm. The 448 bp A + T-rich region was located between rrnS and trnM, and it included the motif ATAGA followed by a 19-bp poly-T stretch and a microsatellite-like (TA)6 element preceded by the ATTTA motif. The phylogenetic tree, inferred using Bayesian inference and maximum likelihood methods, generated similar tree topologies, revealing well-supported monophyletic groups at the tribe level and recovering the relationship ((Satyrini + Melanitini) + ((Amathusiini + Elymniini) + Zetherini)). The close relationship between Satyrina and Melanargiina within the Satyrini was widely accepted. Additionally, Lethina, Parargina, and Mycalesina were closely related and collectively formed a sister group to Coenonymphina. Moreover, A. merlina was closely related to Oeneis buddha within the Satyrina. These findings will provide valuable information for future studies aiming to elucidate the phylogenetic relationships of Satyrinae.