CATFISH GENUS NOTURUS RAFINESQUE 25 



Kentucky and Tennessee to Virginia and North Carolina. All three 

 subgenera have representatives entering portions of the region, and 

 a number of endemics are found there. 



The greatest number of species, twelve, are included in the fauna 

 of Tennessee, followed by Kentucky with nine and thence by Alabama, 

 Arkansas, Mississippi, and perhaps Missouri, with eight; away from 

 this area, the number of species gradually decreases. Nine species are 

 included in the faunas of the Ohio and Tennessee Rivers, decreasing 

 to six known from the Cumberland, White, Arkansas, Ouachita, and 

 lower Mississippi Rivers. 



Because of the favorable ecological habitat available, this general 

 region was probably a refuge for several northern species during 

 Pleistocene glaciation as weU as retaining its native fauna. Subse- 

 quently several species dispersed northward, some farther than others. 

 The relatively northern Noturus flavus was undoubtedly pushed 

 southward by glaciation but it has been able to move into nearly 

 all the upper tributaries of the Mississippi River; it crossed (when 

 or where is not clear) into the Arkansas drainage and utilized post 

 glacial stream changes to enter the Great Lakes at a number of points. 

 The members of the subgenus Rabida were perhaps more eastern and 

 southern in distribution and consequently unable to move into the 

 Mississippi drainage above the Ohio River. For some reason, perhaps 

 because of the sediment load carried by the Mississippi, they have 

 not entered any uppei portion of that system except for a simple 

 crossover of Noturus miurus from the Wabash drainage to the Kas- 

 kaskia drainage in Illinois. This crossover may not have persisted. 



Otherwise two species of Rabida, that were probably pushed south- 

 ward during glaciation, traversed the Wabash River and entered the 

 lower Great Lakes by way of the outlet of glacial Lake Maumee. 

 Aside from Noturus gyrinus, the species of the subgenus Schilbeodes 

 have entered only the lower portions of the Ohio (except apparent 

 recent entrances by A^. insignis) and Missouri River systems and only 

 one (A^. exilis) has moved extensively into the upper Mississippi 

 River drainage. Thus it seems that the major distribution of the 

 species of Schilbeodes was southward and eastw^ard as today and 

 most were not materially affected by glaciation. Noturus insignis, 

 along the Piedmont, was probably restricted southward but it has 

 successfully moved northward again; it has entered the Mississippi 

 and Great Lakes drainages by relatively recent stream changes or 

 human introduction. 



Noturus gyrinus occupies the lowlands fringing the eastern uplands, 

 ranging in waters varying from strongly acid to alkaline and into 

 slightly brackish water. Because it lives successfully in quiet, standing 

 waters it has been able to enter the Great Lakes drainage at a number 



