DistributionRead full entry
Range DescriptionThis species was historically found throughout the Tennessee River system (USFWS 1985). It was probably rare in the Cumberland River, and was also reported from the Ohio, Wabash, Kentucky, Scioto (Ohio) and Kanawha (West Virginia) Rivers (USFWS 1985). It was probably widespread in the larger rivers of the eastern United States and southern Ontario, Canada (USFWS 1985). Currently extant populations of this species (Epioblasma torulosa rangiana) exist within the Allegheny River, Western Pennsylvania, and Southern Ontario, Canada (K. Cummings pers. comm. 2010).
Its extent of occurrence is estimated as around 60,000 km2, although this does encompass large areas where the presence of the species is uncertain. NatureServe (2009) estimates the range extent of this species closer to 1,000-5,000 km2. Its area of occupancy is probably much smaller than this, and anywhere between 100 to 2,000 km2, thus falling within the threshold for threatened categories under criterion B.