Fishes of the IVestern North Atlantic 



421 



lUsha amazonica (Miranda-Ribeiro) 1923 



Apapa, Sardina, Asuna Nahui 



Figure 105 



Study Material. Type of/, apapae, about 200 mm TL (caudal damaged), 160 mm 

 SL; exact place of capture unknown, being registered merely as having been collected 

 in "the Amazon River region, Para to Manaos," Brazil; USNM 52550. 



Distinctive Characters. This species differs from the other local species in having a 



Figure 105. I/iska amazonica, about 200 mm TL (caudal damaged), 160 mm SL, Amazon River, Brazil, 

 type of /. apapae, USNM 52550. Drawn by Ann S. Green. 



ligament between the premaxillary and maxillary; the others have a narrow bone 

 bearing fine teeth along the margin. Its body is slender as in altamazonica, but its scales 

 are apparently somewhat larger, its dorsal rays fewer, and its anal rays more numerous. 

 It has more gill rakers than altamazonica but fewer than the other species herein de- 

 scribed. It is nearest to furthii of the Pacific coast of tropical America, which also 

 has a ligament between the premaxillary and maxillary; but it differs from that species 

 in having fewer ventral scutes (34-37 in furthii), and in the position of the pelvic 

 fin — inserted notably nearer to the origin of anal than to the base of pectoral in ama- 

 zonica but equidistant between these points in furthii; also they differ in several 

 other respects. 



Description. Proportional dimensions in per cent of standard length, and counts, 

 based on Study Material, specimen 1 60 mm SL. 



Body: depth 30.5. 

 Caudal peduncle: depth 8.75. 

 Head: length 25; depth 23.5. 

 Snout: length ^.6. 



Eye: diameter 6.8. 

 Interorbital: width 2.5. 

 Maxillary: length 13.2. 

 Mandible: length 14.5. 



