Pleistocene Glacial Refugia in the Don River Basin: Witness from the Endangered Depressed River Mussel

Abstract

The depressed river mussel Pseudanodonta complanata (Rossmässler, 1835) is an endangered freshwater bivalve with sparse distribution across Europe. Despite its high conservation priority, available data on the current population genetics and biogeography of P. complanata are very limited. In this paper, we studied the genetic diversity and differentiation of P. complanata based on newly sequenced COI and ND1 gene fragments, and on available sequences from the NCBI GenBank. We discovered a localized and highly divergent lineage in the Don River basin and a widespread but low diversified lineage distributed from the Volga River basin to the Oise River in France. A star-like haplotype network, results of mismatch analysis, and significant negative values of neutrality tests reveal that the pan-European lineage went through a bottleneck event. The discovery of the separate lineage in the Don River basin is and additional evidence of the existence of Pleistocene glacial refugia in the south of the Russian Plain. Moreover, this finding confirms the significance of the Azov Sea drainage as a freshwater biodiversity hotspot of great conservation importance.

Not a Silent Invasion: The Reaction of European Naturalists to the Spread of Zebra Mussel (Dreissena polymorpha) in the 19th—Early 20th Century

“…The existence of the Pleistocene refugia situated in Central and Eastern Europe cannot be ruled out either. In a series of recent studies, the application of molecular methods helped to identify such refugia for some species of pearl mussels (Unionidae), another family of freshwater Bivalvia [8,66,68,69].…”