9 



193 



Head with numerous melanophores dorsally. diminishing laterally. Anterior end of snout 

 bearing melanophores. Lower portion of lateral side of head without melanophores. Nu- 

 merous melanophores along margin of lower jaw. Therefore, left and right lower lateral 

 stripe on the body continuous as a black band crossing the anterior end of the snout and 

 lower jaw. Numerous melanophores present on sides of body, except ventral to the lower 

 lateral stripe. Area between upper and lower lateral stripes pale. 



Melanophores present on all fins. On pectoral fin. rays bearing more melanophores than 

 the membranes, the first ray darkest. The posterior three or four rays and membranes al- 

 most lacking melanophores. As a whole, distal part with more melanophores than proxi- 

 mal part. Pelvic fin-rays bearing more melanophores than membrane, and distal part 

 bearing more melanophores than proximal part. Dorsal fin-rays and membrane bearing 

 melanophores: all rays equally pigmented. Base of dorsal fin bearing more melanophores 

 than rest of the fin, forming a black basal patch. All anal fin-rays and membrane, except 

 the most posterior two rays and membrane, bearing melanophores. Caudal fin darkest of 

 all fins. High density of melanophores on middle portion of caudal fin forms a slightly 

 darker patch. A dark spot about size of pupil present at caudal fin base. 



Biology 



Phoxinus erythro gast er occurs in small, clear, and spring-fed streams (Cross 1967. Smith 

 1979, pers. obs.). This species prefers headwaters, and scarity of the permanent springs 

 might limit the distribution of the species in the Plains region (Cross 1967. Smith 1979). 

 This dace can be in schools of a dozen to a few hundred individuals (Smith 1908). The 

 fish species associated with P. erythrogaster include Semotilus atromaculatus, Notropis 

 cornutus, Campostoma anomalum, Rhinichthys sp. and Conus sp. (Smith 1908. Cross 

 1967). A few hybrids of P. eiythrogaster with other species have been described, inclu- 

 ding P. erythro gaster x Luxiliis cornutus ( Hubbs & Bailey 1951. Minckley 1959. Cross & 

 Minckley 1960, Greenfield et al. 1973). P. eiythrogaster x Campostoma anomalum 

 (Hubbs & Bailey 1951). P. eiythrogaster x Notropis nubilus (Phillips & Etnier 1969). P. 

 erythrogaster x Semotilus atromaculatus (Cross & Minckley 1960). and P. eiythrogaster 

 x Notropis pilsbryi (Robinson & Miller 1972). 



The diet of P. eiythrogaster includes diatoms, algae, bits of macrophytes. and small aqua- 

 tic insects (Forbes & Richardson 1920. Phillips 1969b. Cooper 1983). The dace obtains 

 food by nibbling or sucking the surface slime from stone and other objects (Forbes & 

 Richardson 1920). 



The spawning season varies from April to June, depending on the locality, in northern po- 

 pulation from late May to the mid-June, in southern population from April to June (Eddy & 

 Underhill 1974. Settles & Hoyt 1978. Starnes & Starnes 1981). The fecundity was esti- 

 mated from less than 700 (Settle & Hoyt 1978) to about 20.000 eggs (Philips 1969c). The 

 dace can be mature during the first year (Settles & Hoyt 1978. Smith 1979). According 

 to Smith (1908). this species has a complex breeding behavior. 



Distribution 



P. erythrogaster occurs widely from Minnesota and western Pennsylvania, southward to 

 Arkansas and Alabama (Starnes & Starnes 1980). Isolated populations occur on Crowley 



