Complete mitochondrial genome and the phylogenetic position of the pelagic octopus Tremoctopus violaceus (Mollusca: Tremoctopodidae).

Tremoctopus violaceus is a small species of pelagic octopods which inhabit in subtropical and tropical open oceans. The mitogenome of T. violaceus is 16,015 base pairs (bp) in length and contained 13 protein-coding genes, two rRNA genes, and 22 tRNA genes. Sequence analysis showed that the overall base composition is 31.5% for A, 40.47% for T, 7.79% for C, and 20.24% for G. The newly characterized complete mitochondrial genome of T. violaceus will provide essential data for further studies of this endangered species.