All of the taxonomic issues discussed here for Fusconaia spp., Pleurobema spp., and Elliptio spp., are also addressed in Inoue et al. 2018, "The Pleurobemini (Bivalvia: Unionida) revisited: Molecular species delineation using a mitochondrial DNA gene reveals multiple conspecifics and undescribed species" but the citation is omitted from this paper. While Inoue et al. 2018 focused on COI sequences, they are all mitochondrial markers and are thus linked and show similar patterns. All of the taxonomic/barcoding issues regarding these specific taxa are also addressed, though not resolved, in Inoue et al. 2018. Please consider including the citation as that is the most recent and comprehensive work on the group.