Additional molecular data on the protected springsnail species Bythinella viridis (Poiret, 1801) (Gastropoda: Bythinellidae) suggest synonymy of related taxa

Abstract

The taxonomic status of the springsnails B. viridis, B. carinulata and B. lancelevei remains unclear despite the molecular evidence data provided by Benke et al. (2009). Based on extensive sampling and the analysis of COI, 16S, 28S and ITS genes, we investigate analyze the genetic variability of Bythinella populations sampled within the area of occurrence of the three nominal taxa. Topotypic populations of B. lancelevei and B. viridis cannot could not be distinguished. Some of the populations included in the putative area of distribution range of B. carinulata form distinct supported clades, but these distinct clades are not monophyletic and the overall genetic divergence is less than the 3% barcoding gap for species of the genus the barcoding gap of c.a. 3% for Bythinella species. Therefore, we propose to synonymize these three nominal species under the name B. viridis (Poiret, 1801). Our results have important conservation implications, as they significantly expand the range of the protected species B. viridis. This species should be considered in impact studies in a large northeastern quarter of France.