CATFISH GENUS NOTURUS RAFINESQUE 



167 



O «9 



48 



LlI 47 



m 



21 23 25 27 



31 33 35 37 39 41 43 45 47 49 51 53 55 57 59 61 63 65 67 69 71 73 75 



STANDARD LENGTH - mm. 



Figure 4. — Comparison of the number of caudal rays in Noturus eleutherus and Noturus 

 stigmosus. The data are from specimens taken in the Ohio drainage basin, including 

 several lots in which the species were associated. No change in number with age is indicated 

 nor is a sexual difference evident. An overlap exists between 47 and 52 caudal rays, but 

 only an occasional specimen of A^. eleutherus has more than 49 rays and few examoles 

 of A'', stigmosus have less. 



The FURiosus Group 



The/wn'osw5 group consists of four widely separated allopatric stocks 

 (map 13), a geographic situation without known parallel among eastern 

 North American fishes. These populations are named Noturus furiosus, 

 Noturus stigmosus, Noturus munitus, and Noturus placidus. All are 

 characterized by a long, strong, relatively well-serrated pectoral spine; 

 a long humeral process and dorsal spine; a dark, lunate or crescent- 

 shaped midcaudal band; whitish tips of the anterior dorsal rays; a 

 relatively free posterior margin of the adipose fin; and an intermediate 

 number of caudal rays. 



The four disjunct populations differ in certain characters (table 14) 

 which point to the desirability of nomenclatorial recognition. Because 

 these morphological differences, although not strikingly prominent, 

 permit identification of all well-preserved specimens, the four popu- 

 lations are recognized as species. The geographic segregation, however, 



