The first mitochondrial genome of Tetraclita japonica (Crustacea: Sessilia) from China: phylogeny within Cirripedia based on mitochondrial genes

The first mitochondrial genome of Tetraclita japonica from China was presented. The mitochondrial genome of T. japonica CN is a circular DNA molecule containing 15,192 bp. It contains 13 protein-coding genes, two rRNAs genes and 22 tRNAs. Four PCGs, seven tRNAs, and two rRNAs are encoded on the light strand (trnF, nd5, trnH, nd4, nd4L, trnP, nd1, trnL1, lrRNA, trnV, srRNA, trnK, and trnQ), and the other nine PCGs are located on the heavy strand. The length of all non-coding regions is 667 bp and the longest one distributed between srRNA and trnK (263 bp). Interestingly, cox1 of T. japonica CN started with CGA, which is different from most other mitochondrial PCGs whose initiation codon is ATN. In comparison with the pancrustacean ground pattern, seven tRNAs (trnQ, trnI, trnP, trnT, trnS(1), trnE, and trnA) are translocated, and three tRNAs (trnK, trnC, and trnY) are inverted. Phylogenetic tree was constructed based on 13 mitochondrial PCGs. In the phylogenetic tree, T. japonica CN clustered with T. japonica JP into a branch (BP = 100). Tesseropora rosea clustered with T. japonica, and they grouped with T. rufotincta with high support (BP = 100). In the tree, T. divisa as the most distantly related species within Tetraclitidae. Moreover, phylogenetic analysis indicates that the two families (Balanidae and Archaeobalanidae) are non-monophyletic. More mitochondrial genomic data are urgently needed to reveal the deeper phylogeny within Cirripedia.