Taxonomic Reassessment of Freshwater Mussels from the Western Balkans Reveals an Overlooked but Critical Refugium and Defines Conservation Priorities

Abstract

Freshwater mussels are an endangered group of animals, especially in the water bodies of Central and Western Europe. Conservation priorities were established for many endangered freshwater mussel species in the last decade. Here, we present new data on a cryptic refugium of freshwater mussels in the Western Balkans. Two species, Anodonta exulcerata Porro, 1838 and Unio elongatulus Pfeiffer, 1825, were discovered in Montenegro for the first time. The phylogenetic position and taxonomic status of freshwater mussel species from Montenegro were studied by means of an integrative approach, combining morphological data and COI gene sequences. Unio carneus Küster, 1854 stat. rev. represents a species with a restricted range, which is endemic to the Western Balkans. A viable population of Microcondylaea bonellii (Férussac, 1827) was discovered in the Zeta River. This species was not mentioned in Montenegro since the 1900s. A significant level of genetic diversity was revealed for the studied species. In the Skadar Lake basin, freshwater mussels from diverse ecological groups were discovered. Rheophilic species of freshwater mussels may represent ancient lineages, which need special conservation planning. Conservation priorities should be aimed at the protection of freshwater mussel habitats on the Balkan Peninsula.

Distribution Range of the Endangered Species Unio crassus Philipsson, 1788 in Serbia (Western Balkans Region), Historical and Recent Data

“…It was observed that this species is generally vulnerable to environmental degradation, especially to changes in water chemistry [14]. The high level of eutrophication caused by agricultural drainage is considered to be the main reason for the decline of U. crassus [10,22,30,[52][53][54]. Our data show that the mean nitrate-nitrogen concentration varies between the study periods (Figures 7 and 8).…”

Aquatic Biodiversity: Evolution, Taxonomy and Conservation

“…The data obtained by the authors confirm that Unionicola mites are narrow host specialists that are associated with either one or a few closely related freshwater mussel species belonging to one or two sister genera. The taxonomic reassessments of freshwater mussels based on an integrative approach were performed by Lyubas et al [6] on the Western Balkans. Authors present a new data on a cryptic refugium of freshwater mussels in this region.…”