174 



Pharyngeal bone developed, pitted surface flat and wide. Pharyngeal teeth in one row, 5- 

 5, occasionally 4-5, or 5-4. Teeth thin, elongate, and hooked at tip. 

 Vertebrae 37-39; precaudal vertebrae 20-21, caudal vertebrae 17-19. 

 Intestine long with complex loops, six loops in adults. Relative length of intestine increases 

 as the fish grows, its length about 230% of standard length in adults. Gas bladder short 

 and broad. Anterior chamber broad and round anteriorly, its posterior portion not much 

 narrower than anterior portion; anterior chamber 60% of posterior chamber in length. Con- 

 striction elongated, pneumatic duct connecting with middle portion of constriction. Peri- 

 toneum dark in color. 



Tuberculation. Dorsal, lateral and ventral sides of head bearing scattered small tuber- 

 cles. Each breast scale bearing 4-5 tubercles at its apical margin (up to 12 on some scales). 

 Each scale on the anterolateral body bearing 2-5 tubercles in one row located near the 

 apical margin of the scale in most specimens; tubercles in two rows in a few specimens. 

 Scales on upper part of the body sides (dorsal to lateral line) bearing better developed tu- 

 bercles than scales on lower part of sides (ventral to lateral line). Tubercles on apical mar- 

 gin of caudal peduncle scale. Second to fifth pectoral fin rays bearing two rows of tubercles 

 per ray on the dorsal side of the fin, the membrane between the rays also bearing a few 

 tubercles; other fin rays and membrane on the dorsal side, and all rays and membranes 

 on the ventral side, bearing fewer and smaller tubercles. Each pelvic ray bearing one row 

 of tubercles dorsally, and a few tubercles ventrally. Tubercles on dorsal and anal fins small 

 and uniserial. Tubercles absent on caudal fin. 



Coloration. The most characteristic color pattern is a broad dark lateral stripe, exten- 

 ding from in front of anterior nasal opening to base of caudal fin. The left and the right 

 lateral stripes are not connecting each other at the end of the snout. Young with two dark 

 stripes that converge into one on the caudal peduncle. Females bearing less developed 

 stripe than males. Body lateral line extends within the stripe. Numerous small black speck- 

 les randomly present dorsal to the stripe and on dorsum of body and head. Melanopho- 

 res absent dorsally on tip of snout. Mid-dorsal stripe present, interrupted once or twice in 

 the predorsal fin region, and the postdorsal fin region. No melanophores present ventral 

 to lateral stripe and silver in color at ventrolateral sides of body and ventral side of head. 

 A few melanophores present on some pectoral and anal rays, and all dorsal and caudal 

 rays. Base of dorsal fin densely pigmented. Caudal fin darker than other fins. The colo- 

 ration in life was described by Starnes & Starnes (1978). 



Biology 



The biology of R cumberlandensis was studied by Starnes & Starnes (1978, 1981) and 

 CTBara (1990, 1991). The following information is abstracted and summarized from those 

 publications. 



P. cumberlandensis is restricted to small streams with cold and clear water. In Young's 

 Creek of Kentucky where the dace was found, the water temperature is generally below 

 23°C. The dace also requires a ratio of riffle area to pool area 60:40 or below. Fish 

 species associated with the P. cumberlandensis include Semotilus atromaculatus, Rhi- 

 nichthys atratulus, Campostoma anomalum, Pimephales notatus, Catostomus commerso- 



