The tuxedo darter (Etheostoma lemniscatum) is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the Southeast United States in the Cumberland River system. Classification Etheostoma lemniscatum was described only in 2008. It was originally considered a duskytail darter (E. percnurum), but E. percnurum was determined a species complex in 2008 by R.E. Blanton and R.E. Jenkins. Appearance and anatomy It is visually distinguished from other species of the E. percnurum complex by a more posterior anal fin. Geographic distribution Originally, the tuxedo darter (then E. percnurum) was reported only in one location of the Big South Fork of the Cumberland River, which flows from north-central Tennessee to McCreary County, Kentucky. Prior to 1995, the mouth of Station Camp Creek in Scott County, Tennessee contained the only known tuxedo darter population. However, in 2000 D.J. Eisenhour and B.M. Burr discovered six additional sites spanning nineteen kilometers from Station Camp Creek (the original site) to Bear Creek in McCreary County, Kentucky. They estimated the population at 300 to 600 individuals. There are two more sites upstream that have been discovered but data has yet to be published. The Cumberland River is the primary drainage of the Cumberland Plateau, which sits between the Highland Rim and the southern Appalachian Mountains. The plateau contains well-drained soil that is acidic and infertile. The river has eroded through a sandstone crust to its limestone base. The area has a history of industrial and agricultural practices, such as coal mining, that have reduced habitat for all wildlife. However, the region is now protected by the Big South Fork National River and Recreation Area. Ecology and life history The tuxedo darter is a benthic species with cryptic coloration. Tuxedo darters live only one to two years and do not venture far from where they were born. The E. percnurum species complex is unique within its subgenus (Catonotus) because its species prefer larger streams and moderately large rivers. The tuxedo darter is an insectivore that feeds on microcrustaceans and chironomid larvae. It may also feed on heptageniid nymphs on the underside of rocks. They become sexually mature when they are greater than one year old and at least long. Research on the citico darter (Etheostoma sitikuense), another member of the duskytail complex, has shown that it can produce