22 UNIVERSITY OF COLORADO STUDIES 



Catostomus commersonii (Lacepede) 

 Common Sucker 



Cyprinus commersonii Lacepede, Bisl. Nat. Poiss., Vol. V, p. 502, 1803 {locality unknown). 

 Cyprinus teres Mitchill, Trans. Lit. Phil. Soc. N.Y., p. 458, 1815 (New York). 



The Colorado specimens of this species are all referable to a well-defined 

 subspecies, C. commersonii sucklii (Girard), which may be differentiated from 

 the true C. commersonii of the eastern states by the number of rows of papUlae 

 on the upper lip. In C. commersonii commersonii the papillae on the upper lip 

 are usually in 3 rows (2 to 4), while in C. commersonii sucklii they are usually in 5 

 or 6 rows (sometimes 7 or 8) . 



Catostomus commersonii sucklii (Girard) 

 Sdckley's Sucker (Figs. 2, 3, 5, 8, 57 and 58) 



Catostomus sucklii Girard, Proc. Acad. Nat. Sci. Pkila., p. 175, 1856 (Milk River, Montana). 



Catostomus commersonii sucklii (Girard) — Jordan and Evermann, Bull. 47, U.S. Nat. Mus., 

 p. 179, 1896 (eastern Colorado). 



Catostomus teres sucklii (Girard) — Jordan, Bull. U.S. Fish Com., p. 7, 1889 (Denver), p. 11 

 (Twin Lakes; Lake Creek near Granite), p. 16 (Arkansas at Canyon City and Pueblo). 



Catostomus commersonii (Lacepede) — Juday, Univ. Colo. Studies, Vol. II, p. 113, 1903 

 (Longmont and Boulder); Juday, Bull. U.S. Fish Com. for IQ04, p. 226, 190s (Boulder; Long- 

 mont); Bull. U.S. Fish Com., Vol. XXVI, p. 161, 1906 (Twin Lakes); Fowier, Proc. Acad. Nat. 

 Sci. Phila., Vol. LXV, p. 52, 1913 (Twin Lakes). 



Catostomus alticolus Cope — Cope and Yarrow, Wheeler Survey, Vol. V, p. 677, 1875 (Twin 

 Lakes). 



Moxosloma trisignatum Cope — Cope and Yarrow, Wheeler Survey, Vol. V, p. 679, 1875 

 (Pueblo). 



Body elongate, rather terete anteriorly, somewhat compressed posterior to 

 the dorsal fin; depth 4.6 to 5.5 in the length to the base of the caudal; head 

 broad, flattened above, and with rather vertical sides so that it is somewhat quad- 

 rate in cross-section; dorsal profile sloping to the truncate snout, ventral profile 

 almost straight; length of the head 3. 75 to 4. 5 in the length of the body to the 

 base of the caudal; snout broad, heavy, tnmcate, and over-passing the mouth 

 by half the diameter of the eye or more; eye prominent, nearer the gill opening 

 than the tip of the snout, situated near the dorso-lateral margin of the head; 

 diameter of the eye 3 to 4 in the interorbital distance, about the same in the snout, 

 and 5 or 6 in the head; nostrils large and prominent, a little less than the diameter 

 of the eye in front of the eye; the mouth ventral; lips large and fleshy, no indenta- 

 tion at the lateral junction of the upper and lower lips; upper lip with 4 to 8, 

 usually 6 rows of papillae; lower lip deeply cleft in the median line, the indentation 

 being separated from the edge of the lower jaw by not more than two rows of 

 papUlae; cutting edges of the jaws wanting or but poorly developed; mouth as 

 a whole protractile; dorsal fin short and rather high, the length of the longest 



