The complete mitochondrial genome of Mactra quadrangularis (Mactridae).

The whole mitochondrial genome sequence of Mactra quadrangularis (Reeve, 1854) was determined. It had a total length of 16,848 bp and it contained 12 protein coding genes, 2 ribosome RNA genes, and 22 transfer RNA genes. The base composition was 25.75% A, 20.82% G, 11.53% C, and 41.90% T, respectively. Furthermore, state codon of ND4 was ATT; ND1 and CYTB were ATA; COX1 was GTG; ND5, COX2, ND4L, ND6, ND2, COX3, ATP6, and ND3 were ATG. Phylogenetic analysis demonstrated that M. quadrangularis was most closely related to Mactra chinensis. The mitochondrial genome will provide reference for the further investigation and research of M. quadrangularis.