Molecular resources combined with morphology and geography to provide insights into the evolutionary history of a wide-ranging freshwater mussel species complex (Unionida: Quadrula)

The freshwater mussel Quadrula quadrula of eastern North America occupies several isolated river drainages along the coastal Gulf of Mexico and northward in the Mississippi Basin and Great Lakes. Previous work has documented high morphological and genetic variation across its range but due to paraphyly of mitochondrial barcodes, variants are currently recognized as conspecific. Here we present sequence data from three genomes including male- and female-inherited mitochondrial markers and thousands of nuclear encoded SNPs that were used to disentangle the evolutionary history of this species complex. We also provide morphological and geographic data, which was analyzed with the molecular data in a comparative context to illuminate the group’s divergence history.