.«•' 



''■ ■ ■',; ■".. 256 



Comments 



This species has occasionally been confused Avith an undescribed form from 

 the lower and middle Amazon basin. This problem probably results from their 

 superficially similar striped coloration, as well as possible confusion surrounding the 

 type locality of vittatus. Steindachner gave the type locality as the mouth of the Rio 

 Purus in Brazil. In the present study, no specimens of ^. vittatus were found from 

 this area, although the species is known from the upper Amazon basin in Bolivia 

 and Ecuador. Thus, it would appear possible that the species could be, or at one 

 time was present, in the Rio Purus or near its mouth in the Rio Solimoes. 

 Conversely, the type locality as given by Steindachner may be erroneous. This 

 possibility cannot be unequivocally refuted, given the fact that there have been 

 occasional mistakes identified with locality records kept by Steindachner (C. R. 

 Gilbert, personal communication). 



An unpublished manuscript name has been proposed for this species by 

 colleagues in Venezuela (O. Castillo, A. Machado Allison, and F. Provenzano, 

 personal communication), who are of the opinion that the form in the middle 

 Orinoco basin represents an undescribed species. I have expressed to them my 

 belief that the name vittatus applies to the Orinoco form; however, they apparently 

 do not agree, inasmuch as they recently (June 1989) informed me that they intended 

 to proceed with a formal description of this taxon. 



Specimens in the Umited amount of material from Bolivia and Ecuador have 

 a somewhat more mottled pigmentation pattern than those typically collected from 

 Whitewater rivers in the middle Orinoco, In addition, the number of pectoral fin 

 rays in these specimens averages one higher than in specimens from the Orinoco 

 basin. Individuals from the Orinoco, nevertheless, are capable of dramatic 

 coloration changes when collected from, or placed in, clear or dark water (see 



