FAMILY CATOSTOMIDAE 



119 



Diagram 5. Lower lip arrangement in Moxostoma. (A) Moxostoma anisurum, 



showing halves meeting in an acute angle. (B) Moxostoma aureolum, 



showing halves meeting in a straight line. 



very obtuse in large adults, and obliterated when the mouth is protruded; 

 mouth rather large; head rather squarish when seen from side, front, or 

 above, and long (in adult contained 3.7-4.4 times in standard length; in 



young 1-3 inches long contained 3.3-3.7 times in standard length) 15 



Halves of lower lip meeting in a straight line (in the very young at an obtuse 

 angle; the margin often somewhat convex in adults) ; mouth small; head 

 bluntly subcorneal and short (in adult contained 4.3-5.4 times in standard 

 length; in young 1-3 inches long, about 3.5-3.8 times) ; developed dorsal 



rays usually 12-13; adults living chiefly in large rivers and lakes 



Northern Redhorse, Moxostoma aureolum (LeSueur) 



15. Developed dorsal rays 11-15, usually fewer than 15; plicae of lips not broken 

 up by transverse creases into papillalike elements; lips not much constricted; 

 length of depressed dorsal fin less than two-thirds distance from dorsal fin to 

 tip of snout; length of dorsal fin base decidedly less than distance from dorsal 



fin to occiput (back of skull) 16 



Developed dorsal rays 14-17, usually 15 or 16; plicae of lips more or less 

 completely broken up into papillalike elements; lips notably constricted; 

 length of depressed dorsal fin more than two-thirds distance from dorsal 

 fin to tip of snout; base of dorsal fin about equal in length to distance 



forward to occiput; found chiefly in large rivers or lakes 



Silver Redhorse, Moxostoma anisurum (Rafinesque) 



16. With dark spots or crescents on the scale bases; caudal fin bright red; tip of 

 dorsal fin whitish near margin in adult; size large, usually more than 15 

 inches long in adults; adults living mainly in large rivers and lakes except 



when spawning; lateral line 42-46 scales 



Greater Redhorse. Moxostoma ruhreques Hubbs 



Without dark spots or crescents on the scale bases; caudal fin olive; tip of 

 dorsal always black or blackish near margin; size smaller, probably not 

 reaching 15 inches in length; adults living chiefly in smaller streams; lateral 



line 38-44 scales, usually 39-40 



Golden Redhorse, Moxostoma erythrurum (Rafinesque) 



