Specimen was collected the creek is relatively small (approximately 30 ft wide), but 

 subject to strong freshwater tidal fluctuation of about a 4 ft vertical magnitude. 

 During the tidal periods the current is very strong. The specimen was taken in a 

 shallow, muddy cove of the river near the bank, shaded by forest vegetation. Other 

 fishes collected in this area included Ageneiosus brevifilis,A. ucayalensis, Bryconops 

 caudomaculatus, Leporinus frederici, Hoplias sp., and Serrasalmus rhombeus. 



Etymology 



. -M From the Latin marmor, neuter gender, meaning marble, in reference to the 

 strongly mottled coloration pattern on the head, body, and fins. ;. 



Comments -^ *j '■,''" ■. ' 



Fowler (1915) suggested that>l. marmoratus (and alsoy4. ogilviei) was very 

 close, and possibly identical to^l. brevifilis. He did not explicitly state his reason for 

 this conclusion; however, it is probable that Fowler's implication was based on 

 similarities in body shape and meristics, particularly anal fin rays. In the present 

 study, y4. marmoratus could not be reliably separated fromy4. brevifilis on the basis of 

 meristics. 



It is possible thaty4. marmoratus is synonymous with A. brevifilis, and that the 

 bold coloration pattern is characteristic of juveniles and subadults. This possibihty 

 seems even more likely, given the fact that all specimens of marmoratus examined 

 are of a relatively small size (45-183 mm), whereas the majority of specimens of 

 brevifilis examined exceed this length considerably. Furthermore, no nuptial male 

 specimens of marmoratus were observed, although the sample size was very hmited. 

 The relatively large holotype of marmoratus (148.5 mm) has the characteristic 



