Pleurobema sintoxia DArTseq
Freshwater mussels (Bivalvia: Unionida) are a highly diverse group with approximately 1000 species recognized globally and 388 endemic to North America. Although taxonomically diverse, this group is also one of the most threatened in North America with over 65% of the species considered of conservation concern. In this study, we investigate the relationships within and among extant populations of P. rubrum and P. sintoxia to resolve taxonomic uncertainties, better understand historical demographics, and help guide conservation action. Specifically, we analyzed DNA sequence data from two maternally-inherited mitochondrial (mtDNA) genes, one nuclear DNA (nDNA) locus, and genome-wide single nucleotide polymorphisms (SNPs) generated using genotype-by-sequencing (GBS) to 1) test the morphology-based taxonomic hypotheses hypothesis thatfor P. rubrum and P. sintoxia represent distinct species, 2) infer genetic structure across the ranges of both P. rubrum and P. sintoxia, 3) test demographic hypotheses of extant populations based on glacial dynamics, 4) synthesize possible drivers of the observed genetic variation, and 5) discuss the conservation implications of our findings. The results of our study have direct implications for conservation actions and provide another empirical example of the effects of glacial dynamics on genetic variation in aquatic taxa.