The complete maternal mitochondrial genome sequences of two imperiled North American freshwater mussels: Alasmidonta heterodon and Alasmidonta varicosa (Bivalvia: Unionoida: Unionidae)

The freshwater mussels Alasmidonta heterodon and A. varicosa historically inhabited rivers along the North American Atlantic coast from the Carolinas, U.S.A., to New Brunswick, CA. However, many populations have been extirpated, and A. heterodon is now federally listed in the U.S.A. as endangered, and both A. heterodon and A. varicosa are listed as vulnerable on the IUCN Red List. To facilitate genetic study of these species, we sequenced the complete female mitochondrial genomes of A. heterodon (15,909 bp; GenBank accession no. MG905826), and A. varicosa (15,693 bp; GenBank accession no. MG938673). Both mitogenomes contained 14 protein coding genes, 2 rRNA genes, and 22 tRNAs with the same gene order as reported for other members of the subfamily Anodontinae. When these two genomes were put into a phylogenetic context with other members of the Unionidae, they clustered together with other species in the subfamily Anodontinae, Tribe Anodontini.