The complete mitochondrial genome of a fouling mussel, Xenostrobus atratus (Mollusca: Mytilidae), and its phylogenetic implication

In this study, we report the female-lineage mitochondrial genome of Xenostrobus atratus for the first time. The circular mitochondrial genome is 14,806 bp in length and contains 12 protein-coding genes, 22 transfer RNA genes, and two ribosomal RNA genes. All genes are encoded on the heavy strand. The genome composition is A + T biased (66.6%), with 25.2% A, 41.4% T, 21.7% G and 11.7% C. A Bayesian inference (BI) phylogenetic tree was constructed based on the mitochondrial genomes of X. atratus and 46 other Mytilidae species. Our results demonstrate that X. atratus and Limnoperna fortunei have distinct lineages, opposing synonymizing Xenostrobus within Limnoperna. According to this study, the validity of the subfamily Limnoperninae and genus Xenostrobus is strongly supported. However, there is still an urgent need for more mitochondrial data to decide to which subfamily X. atratus belongs.