Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: > 300
Comments: Basch (1963) notes it is very widely distributed with a septate form known from California, Texas, Michigan, New York, and other areas. In Indiana, Pyron et al. (2008) found it in three streams (Clear Creek in Huntington Co., Coal Creek in Fountan Co. and the Tippecanoe River in Kosciusko Co.) of 123 sites surveyed compared to historical ocations in Clear Lake and a pond in La Porte Co. (Goodrich and van der Schalie, 1944). It is fairly common in New York (Jokinen, 1992). In Pennsylvania, it occurs in the Delaware and Ohio basins (Evans and Ray, 2010). It has not been observed in Iowa since 1912 (Stewart, 2006). In Alabama, it is common and presumably found throughout Alabama (Mirarchi, 2004). Branson (1966) documented Spring River in Missouri and Kansas. In Missouri, Wu et al. (1997) list Holt Co. near the Missouri River and Perry Co. near the Mississippi River with the septate form collected only from Stoddard Co. in the Lowland Region. Branson and Batch (1987) documented it in Kentucky in a spring seep in Harlan Co. and the Salt River in Mercer Co. and previous locations in Jefferson and Madison Cos. Blair and Sickel (1986) documented it in 1 of 44 sites (pool in Lost Creek, Tennessee) surveyed in Land Between the Lakes (national recreation area between Cumberland River (Lake Berkeley) and Tennessee River (Kentucky Lake)) in Kentucky and Tennessee. Dozens of occurrences are known from Atlantic Georgia (Dillon et al., 2003), South Carolina (Dillon and Stewart, 2003) and North Carolina (Dillon et al., 2003) in the Piedmont, Southeastern Plains and Southern Coastal Plains including Lake Waccamaw, Neuse River, Singletary Lake, and Carteret and Guilford Cos., North Carolina (Dawley, 1965). Shostak (pers. comm., in Lepitzki, 2001) found 2 specimens at Mariana Lake, between Lac La Biche and Fort McMurray, Alberta, in 1990.