254 



■ ■.,'' -''-"'^ ' 



origin or beyond. Sublateral stripe angled obliquely downward and often 

 terminating above pelvic fin base. Both lateral stripes occasionally broken into a 

 series of elongate spots. Midlateral musculature along posterior portion of lateral 

 line often with melanophores deeply embedded beneath superficial epidermis. In 

 extremely dark specimens, the dorsal and lateral stripes form a dense reticulated 

 network of blotches. > • . , - 



Caudal fin with a very prominent pair of large, black or brown spots of much 

 greater contrast than in any other species. Upper spot crescent shaped, contiguous 

 anteriorly with dorsal stripe, extending over middle of upper principal rays. Spot in 

 middle of lower caudal fin lobe oval to crescentic, opposite spot in upper lobe. In 

 lightly pigmented specimens the spots are less discrete, and the lower one may be 

 very small to nearly absent, whereas in very darkly colored specimens both spots 

 merge to form a broad crescentic band. Remainder of caudal fin generally with 

 little or no pigmentation in most specimens. Dorsal fin with diffuse black along 

 leading edge of spine, and occasionally with specks on distal portion of interradial 

 membranes. Adipose fin pale except at base. Paired fins with scattered brown on 

 upper surface, ranging from very few diffuse specks to one or more stripes along 

 anterior rays. Anal fin typically immaculate or with a few scattered spots at base. 

 Chin, throat, and belly normally unpigmented. In melanistic specimens, the entire 

 body, including the fins, may become heavily mottled and spotted (Fig. 2). 



Distribution 



Presently known from the Rfo Orinoco basin of Venezuela, and from the 

 upper Amazon basin in the Rio Beni drainage of Bolivia and the Rio Napo drainage 

 of Ecuador (Fig. 46). This species is relatively common in the middle Orinoco 

 basin, as revealed by 13 years of recent survey work by Donald C. Taphom (MCNG) 



