Complete Mitochondrial Genome of Myra affinis (Decapoda: Brachyura: Leucosiidae) and Its Phylogenetic Implications for Brachyura

Knowledge of complete mitochondrial genomes (mitogenomes) can help understand the molecular evolution and phylogenetic relationships of various species. To date, the phylogenetic status of Leucosiidae within Brachyura remains unresolved because of the limited number of mitogenomes available. In the present study, the complete mitogenome of Myra affinis was sequenced using next-generation sequencing to supplement the limited mitogenome information of Leucosiidae. The 15349 bp-long mitogenome includes 13 protein-coding genes (PCGs), 22 transfer RNAs (tRNAs), 2 ribosomal RNAs (rRNAs), and a putative control region. The overall base composition is 34.5% A, 36.1% T, 11.5% G, and 17.9% C, with a high AT bias (70.6%). All 13 PCGs start with the standard ATN codon and stop with the TAN codon or incomplete T. Except for tRNA-Ser , all other tRNAs have a typical cloverleaf-like secondary structure. Phylogenetic analyses based on the maximum likelihood and Bayesian inference methods are employed to generate identical phylogenetic topologies, thereby supporting the sister relationship between Leucosiidae and Matutidae for the first time. The monophyly of Eubrachyura is well established, and its sister relationship with Raninoida is strongly supported. The results of this work will not only help achieve a better understanding of the characteristics of the M. affinis mitogenome and the phylogenetic position of Leucosiidae, but also provide relevant information for further studies on the phylogeny of Brachyura.