Eastern blacknose dace (atratulus) is supposedly in the Roanoke basin and northward. The New (Kanawha),Yadkin, Santee (Catawba, Broad, Saluda), Savannah, Tennessee, and Gulf drainage populations should all be Western (obtusus) according to recent genetic studies. Separating them visually is pretty near hopeless; both are quite variable in appearance. I imagine they'd be very susceptible to "headwater stream capture" between drainage basins, and bait bucket transport in areas where their ranges are close. I'm guessing Dustin's ID of "western" is based only on location, right?
Molecular Phylogenetics of the Eastern and Western Blacknose Dace, Rhinichthys atratulus and R. obtusus (Teleostei: Cyprinidae). Michelle Kraczkowski and Barry Chernoff. Copeia Jun 2014 : Vol. 2014, Issue 2, pg(s) 325-338 doi: 10.1643/CG-14-002. http://www.bioone.or....1643/CG-14-002
Gotcha, guess that makes sense. Thanks Gerald.