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57 



Coloration 



Though coloration (or color pattern) of some cyprinids varies intraspecifically, the colo- 

 ration of other cyprinids is useful for identification of the species (e.g., Yang & Huang 

 1964) and for phylogenetic analyses of some species or genera (e.g., Howes 1985). Color 

 patterns for identification of the species include bands and stripes (number, shape, and lo- 

 cation), speckles (size, shape, number and distribution), and the overall color of the body. 

 However, as discussed by many authors (e.g., Heese 1981) and below, the color pattern 

 might change ontogenetically and/or sexually in some species. 



Generally, Phoxinus is a very colorful group of fishes. In fact, P. erythrogaster is consi- 

 dered by some authors to be the most beautiful North American freshwater fish (e.g., For- 

 bes & Richardson 1920). All Phoxinus species bear either horizontal stripes or vertical 

 bands (bars), or both. 



The pigmentation described and compared below is based on alcoholic preserved adult 

 specimens. The coloration of juveniles is mentioned in some cases for the ontogenetic 

 change of the coloration in order to determine the polarity of the transformation series. 

 Numerous melanophores are irregularly present on the lateral body. In addition, all Pho- 

 xinus species bear vertical bands or horizontal dark stripes on the lateral body, and a dor- 

 sal dark stripe on the dorsum of the body extending from nape to in front of caudal fin. 

 Based on the number, size, and shape of the stripes and bands on the lateral body, four 

 types of the color patterns can be recognized on the lateral body in the Phoxinus species 

 (Fig.22A-F). 



1) P. neogae us-type (Fig.22A): Only one uninterrupted horizontal stripe is present from 

 the anterior end of the snout to the base of the caudal fin along the middle of the lateral 

 body. The stripe is almost equal in width along its length. This type is present in P. neo- 

 gaeus, cumberlandensis, issykkulensis, and brachyurus. In young individuals of P. cum- 

 berlandensis, the stripe is narrow and almost equal in width along its length (similar to 

 other species in this type), but it is much broader in adults of the species. 



2) P. ore as-type (Fig.22B): Lateral body bears one horizontal stripe and a few verti- 

 cal bands. This type is observed in P. oreas only. The vertical bands are dorsal to the 

 horizontal stripe which is interrupted into two sections (anterior and posterior section) at 

 about the position of the anal fin. The anterior section of the horizontal stripe gradually 

 curves down to base of the anal fin. 



3) P. erythro gaster-typz (Fig.22D): Lateral body bears two horizontal stripes with- 

 out vertical bands. This type is present in P. erythrogaster, eos, and tennesseensis. In these 

 species the lower horizontal stripe is broader and longer than the upper one. The lower 

 one extends from the anterior end of the snout to the base of the caudal fin. In P. erythro- 

 gaster and eos, the upper strip is broken into blotches along the caudal peduncle. 



4) P. phoxinus-iypt (Fig.22F): Lateral body has about 10 to 15 vertical bands without 

 horizontal stripes. All vertical bands are almost equal in width, as well as the spaces 

 between two bands. This type is present in P. phoxinus only. 



The dorsal portion of the lateral body (dorsal to the lateral stripe) bears a few big speck- 

 les in P. brachyurus and P. oreas. 



