Percina nasuta

Morphological and mtDNA analyses confirmed the distinctness of Percina brucethompsoni (previously recognized as sp. 12 in this database) from P. nasuta. Phylogenetic analysis of DNA sequences sampled from two regions of the mitochondrial genome indicate that P. brucethompsoni is the sister species of P. nasuta populations in the White River drainage (Robison et al. 2014).

Spotty distribution in Arkansas, Missouri, and Oklahoma; small populations; vulnerable to local extirpation resulting from habitat alteration (e.g., stream impoundment and reduced water quality); current status and level of threat need to be clarified.

This darter is distributed sporadically in the St. Francis, White, Little Red, and Arkansas river drainages in the Ozark uplands of southern Missouri, northern Arkansas, and eastern Oklahoma (Page and Burr 2011). Recently identified distribution in Arkansas, includes Lee Creek, Frog Bayou (=Clear Creek), Mulberry River, upper White River, War Eagle Creek, Big Piney Creek, Illinois Bayou Drainage, Ouachita River, Caddo River, and South Fourche la Fare River (Robison 1992a and 1992b). Longnose darters have not been collected in the White River in Missouri since the mid-1950s (Pflieger 1997).

The populations in the Ouachita River drainage have been reassigned to P. brucethompsoni (Robison et al. 2014).

As of the early 1990s, longnose darters occurred in 13 different streams, in three major river systems (see Stewart 1993).

Historical declines were due to habitat modification resulting from reservoir construction (Buchanan 1984, Wagner et al. 1984, Robison and Buchanan 1988, Robison 1992a and 1992b, Stewart 1993). Known threats include impoundment, drought, pollution, and altered temperature and flow regimes downstream from impoundments (Robison 1992a and 1992b, Wagner et al. 1984). Spraying of pesticides may also have a negative effect on survival (see Wagner et al. 1984). Water quality changes caused by agricultural runoff, municipal and industrial discharges, and physical alterations may have caused declines, but reservoir construction has been the major cause of extermination of many populations (Buchanan 1984). Other detrimental impacts include gravel and sand mining, channel modification for flood control, sedimentation, and water quality degradation from point and non-point sources (see Stewart 1993).

Despite these factors, as of the early 1990s, there was little or no evidence to suggest that the species was threatened (Stewart 1993). The species occurred in 13 different streams, in three major river systems; beyond the proposed second phase of reservoir construction on Lee Creek, there were few identifiable threats (see Stewart 1993). Nevertheless, the species was categorized as "threatened" by Warren et al. (2000) and Jelks et al. (2008).