Alabama Moccasinshell Medionidus acutissimus. Uncommon. Occurs in the Mobile Basin and Gulf Coast drainages. Widespread but localized in Mobile Basin. Apparently extirpated from Gulf Coast systems. Usually occurs in riffles and shoals. Listed as threatened by the U.S. Fish and Wildlife Service. HIGH CONSERVATION CONCERN.
Cumberland Moccasinshell Medionidus conradicus. Rare. Endemic to Cumberlandian Region. Remnant populations are found in Paint Rock River system and Spring Creek system in Colbert County. Occurs in moderate to swift current. HIGHEST CONSERVATION CONCERN.
Coosa Moccasinshell Medionidus parvulus. Extirpated. Endemic to Mobile Basin. Historically widespread in the system, now in a few localized populations in Coosa River headwater tributaries in Georgia. Found in riffles and shoals. Listed as endangered by the U.S. Fish and Wildlife Service.
Gulf Moccasinshell Medionidus penicillatus. Rare. Endemic to Apalachicola Basin and Econfina Creek, Florida. Occurred in Chattahoochee and Chipola river systems. Remnant populations are found only in Big Creek, Houston County. Listed as endangered by the U.S. Fish and Wildlife Service. HIGHEST CONSERVATION CONCERN.
