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,...

Evolutionary Placement Analysis (EPA, Berger et al. 2011) would be a more appropriate method here than using consensus sequences derived from environmental samples to generate a phylogeny. This method was developed for exactly this type of analysis. Consensus sequences from environmental samples may be chimeras of different sequences, however no attempt appears to be made to identify chimera seque...