CATFISH GENUS NOTURUS RAFINESQUE 179 



Lower-half caudal rays: (a) 35 (22-26) 24.03; (b) 60 (23-26) 24.62; 

 (c) 11 (23-26) 24.27; (d) 3 (25) 25.00; (e) 3 (23-25) 24.00; (f) 6 (24-25) 

 24.83; (g) 18 (22-25) 23.50; (h) 7 (23-25) 24.43; (i) 143 (22-26) 24.30. 



Upper-half caudal rays: (a) 35 (25-30) 27.23; (b) 61 (24-29) 26.39; 

 (c) 11 (24-29) 27.18; (d) 3 (26-27) 26.33; (e) 3 (24-27) 25.67; (f) 6 

 (26-31) 28.00; (g) 18 (25-28) 26.67; (h) 7 (25-28) 26.71; (i) 144 (24-31) 

 26.76. 



Total caudal rays: (a) 35 (49-55) 51.26; (b) 60 (47-54) 51.03; (c) 11 

 (47-55) 51.55; (d) 3 (51-52) 51.33; (e) 3 (47-51) 49.67; (f) 6 (50-56) 

 52.83; (g) 28 (47-55) 50.29; (h) 7 (49-53) 51.14; (i) 153 (47-56) 51.04. 



Vertebrae: Shenango R., Pennsylvania 26 (33-35) 33.77; Muskingum 

 R., Ohio 5 (33-34) 33.60; Scioto R., Ohio 9 (32-35) 33.56; Huron R., 

 Michigan 31 (31-35) 33.58; Licking R., Kentucky 1 (34) 34.00; 

 Wabash R., Indiana 11 (32-34) 33.45; western Tennessee 7 (33-34) 

 33.57; total 90 (31-35) 33.62. 



Etymology. — The name stigmosus (Latin adjective) means marked 

 or branded and is used in reference to the color pattern, especially the 

 two light spots which are usually present immediately anterior to the 

 dorsal fin, and the brownish chromatophores found anteriorly on the 

 abdomen. 



Remarks. — This species has been confused with and identified as 

 Noturus eleutherus because of the presumed sexual dimorphism. A 

 comparison of characteristics of these species is given in table 13. 

 The differences in caudal rays in stigmosus and eleutherus are shown in 

 figure 4. 



Relationships. — The morphology and color pattern indicate this 

 to be a member of the furiosus species group. In that group it is 

 closest to Noturus munitus Suttkus and Taylor in its geographic 

 distribution and general morphology. The two exhibit considerable 

 similarity in color pattern and in body shape. N. stigmosus differs 

 consistantly from N. munitus, in each river system from which it is 

 known, in higher average numbers of vertebrae, anal rays, caudal 

 rays, especially the upper simple and branched caudals, in distribu- 

 tion of pigment, in having a generally smaller head, and in apparently 

 attaining a larger size. 



Ecology. — Noturus stigmosus occupies small rivers and creeks in 

 western Tennessee. In this area the bottom consists of sand, often 

 shifting sand, and mud, and the water varies from clear to turbid, 

 with moderate current. There is little cover aside from tree limbs, 

 fallen logs, and occasional drifts of miscellaneous debris. The few 

 specimens, all large, that have been collected suggest lack of congrega- 

 tion of individuals, as they have been found scattered over consider- 

 able distances in a stream. 



In the Ohio VaUey and Michigan, N. stigmosus usually inhabits 

 large streams and rivers. There, it probably avoids extremely sUty 



