The complete mitochondrial genome of Onustus exutus(Gastropoda: Xenophoridae)

Complete mitochondrial genome of Onustus exutus has been sequenced and phylogenetic relationships were evaluated. The circular mitochondrial genome is 16,043 bp in length consisting of 13 protein-coding genes, 22 transfer RNA genes, and 2 ribosomal RNA genes. The nucleotide composition of the complete mitochondrial genome of O. exutus is 30.46% A, 14.32% C, 15.83% G, and 39.38% T. With the exception of eight tRNA genes, all other mitochondrial genes are encoded on the heavy strand. Thirteen protein-coding genes start with ATG. For the stop codon, CYTB, ND6, ND4L, and ND4 end with TAG, other 9 genes end with TAA. Phylogenetic tree was constructed based on 13 protein-coding gene sequences of 11 species using the neighbor-joining method, and the result showed that O. exutus is most closely related to Conomurex luhuanus. This is the first record of complete mitochondrial genome from the genus in the Onustus. The present study provides additional data for Mesogastropoda phylogeny.