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Range DescriptionHistorically, this species occurred in the Ecofina, Apalachicola-Chattahoochee-Flint, Ochlockonee, and Suwanee systems in 57 localities (96 records) in Alabama, Georgia, and Florida (Brim Box and Williams 2000). It still exists in all four systems but subpopulations have been lost in the Apalachicola-Chattahoochee-Flint (Chattahoochee River main stem, Randall, Uchee, and Little Uchee Creek; most of Flint River main stem, Patsiliga, Little Patsiliga, Sandy Mount, Gum, Cedar, Chokee, Abrams, Mill, Little Pachitla, and Dry Creeks; Apalachicola River main stem; Spring, Rocky, Marshall, Big, and Cowarts Creeks), and it is nearly extirpated from Alabama (USFWS 2003). In Alabama, it is confined to headwaters of Chipola River and lower Chattahoochee River system with one known extant population in Big Creek, a headwater tributary of Chipola River, Houston Co. (Mirarchi et al. 2004).
The Oval Pigtoe is a wide-ranging species (1,412 km in 11 watersheds) that has lost 73% of its historic extent of occurrence, but still persists in 386 km of several watersheds with an area of occupancy of less than 500 km2. One entire basin of the Oval Pigtoe's distribution, the Suwannee River, is disjunct from the rest, and may represent genetic differences at the species level (USFWS 2003).