Biodiversity and Systematics, Department of Biological Sciences, University of Alabama, 425 Scientific Collections Building, Box 870345, Tuscaloosa, AL 35487-0345, USA.
Mol Ecol Resour. 2008 Jul;8(4):711-24. doi: 10.1111/j.1755-0998.2008.02108.x.
Freshwater mollusks are highly imperiled, with 70% of the North American species extinct, endangered, or at risk of extinction. Impoundments and other human impacts on the Coosa River of Alabama, Georgia and Tennessee of the southeastern USA alone are believed to have caused 50 mollusk species extinctions, but uncertainty over boundaries among several putatively closely related species makes this number preliminary. Our examination of freshwater mussels collected during an extensive survey of the upper-drainage basin, DNA barcoding and molecular phylogenetic analyses confirm the rediscovery of four morphospecies in the genus Pleurobema (Unionidae) previously thought to be extinct from the upper Coosa basin. A fifth 'extinct' form was found in an adjoining basin. Molecular data show that the Coosa morphologies represent at least three species-level taxa: Pleurobema decisum, P. hanleyianum and P. stabile. Endemism is higher than currently recognized, both at the species level and for multispecies clades. Prompt conservation efforts may preserve some of these taxa and their ecosystem.
淡水贝类高度濒危，北美 70%的物种已经灭绝、濒危或面临灭绝的威胁。仅在美国东南部的阿拉巴马州、佐治亚州和田纳西州的科罗拉多河，水坝和其他人类活动就被认为导致了 50 种贝类灭绝，但由于几个假定密切相关的物种之间的界限存在不确定性，这个数字只是初步的。我们对在对上游流域进行广泛调查期间收集的淡水贻贝进行了检查，DNA 条形码和分子系统发育分析证实，以前认为已经从科罗拉多河上游流域灭绝的 Pleurobema 属（贻贝科）中有四个形态种重新被发现。在相邻的流域中发现了第五种“已灭绝”的形态。分子数据表明，科罗拉多形态代表了至少三个种级分类群：Pleurobema decisum、P. hanleyianum 和 P. stabile。特有性高于目前的认识，无论是在种水平还是在多物种进化枝水平上。及时的保护措施可能会保护这些物种及其生态系统。
