Family CATOSTOMIDAE 



THE SUCKER FAMILY 



The body of fishes of the sucker family is generally elongated and in 

 some species is much compressed, but in others it is heavy and thick. 

 The body is covered with smooth-edged scales; the head is scaleless. 

 The mouth varies in size but is always so constructed that it can be 

 drawn out to a considerable extent, thus enabling the fish to take food 

 from the bottom of the stream or lake. No teeth are present on the jaws; 

 the pharyngeal bones are set with numerous teeth that are somewhat 

 similar to those of a comb. The gill-membranes are united to the isthmus 

 (page 57) . The dorsal fin contains 10 or more soft rays but no spines; 

 the caudal fin is forked; the ventral fins are inserted far back on the 

 abdomen; the pectoral fins are inserted on the lower part of the body. 

 The air bladder is large and is in two or three parts. Nine genera and at 

 least seventeen species probably occur in Minnesota and neighboring 

 states. 



The members of this family are largely American, though one species 

 extends to Siberia and another occurs in China. None of the members 

 of this family bite very readily on baited hooks. Some species are 

 caught in seines and in other ways. They are used extensively for food, 

 though they are all quite bony. Some species of the genera Catostomus 

 and Moxostovia are sold commercially under the name "mullet." 



Key to Common Species of Family CATOSTOMIDAE 



1 . Dorsal fin long, with 25-40 rays 2 



Dorsal fin short, with 10-18 rays 8 



2. Eyes in front part of head; head large, not abruptly slenderer than the body: 



scales large, less than 40 in lateral line 3 



Eyes in back part of head; head small and slender; body 6-7 times length 



of head; scales more than 50 in lateral line 



Blue Sucker, Cycleptus elongatiLs (LeSueur) 



3. Posterior fontanelle (soft spot at back of skull) present; anterior fontanelle 

 (soft spot between eyes) absent or much reduced; cheek somewhat shallow 

 and foreshortened (distance from eye to lower posterior angle of preopercle 

 about three-fourths that of upper corner of gill-cleft) ; pharyngeal arch 



heavy, triangular in cross section; subopercle deepest at middle 4 



Posterior and anterior fontanelles both present; cheek relatively deep and 

 long (eye about equidistant from upper corner of gill-cleft and lower 

 p>osterior angle of preopercle; pharyngeal arch almost paper-thin; subopercle 

 deepest below middle (Genus Carpiodes) 6 



4. Mouth large, very oblique, protractile forward; upper lip about level with 

 lower margin of orbit; lips thin and only faintly striated; gill-rakers on first 

 arch as long as the giU-filaments of anterior row, nearly 100 (counted from 

 posterior face of arch) 



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