Fishes of the Western North Atlantic 



419 



in SL; a sheath composed for the most part of two rows of scales at its base. Pelvic fin 

 small, inserted fully an eye's diameter in advance of vertical from origin of dorsal and 

 a little nearer to base of pectoral than to origin of anal, 3.15—3.45 in head; free axillary 

 process about (i(> "jo of the length of fin. Pectoral fin reaching well beyond base of 

 pelvic, its length 4.4—4.9 in SL, 1. 15— 1.3 in head; a free axillary process present along 

 about 66 '/o of length of fin. 



Color. Old preserved specimens grayish brown above, silvery below, with indefi- 

 nite alternating light and dark streaks along the rows of scales. A slight shoulder spot 

 present. Interorbital, upper surface of snout, and tip of mandible dark brown. Dorsal, 

 caudal, and pectoral fins largely dusky, the lower lobe of caudal with a dark area on its 

 middle rays, this area narrow anteriorly but spreading posteriorly. 



Range. Originally described from the Ambyiacu River, a tributary emptying into 

 the Amazon near Pebas, Peru; also reported from Iquitos, Peru, and the Tocantins 

 River, Brazil. The three specimens now at hand are from the lower Amazon. 



Synonyms and References: 



Pellona ahamazonica Cope, Proc. Acad. nat. Sci. Philad., 1872: 265 (orig. descr.; type local. Ambyiacu R., 



trib. of upper Amazon). 

 Ilisha a/tamazonica Eigenmann, Rep. Princeton Exped. Patagonia, 1896-1899, J (4), 1910: 452 (ref., range); 



Eigenmann and Allen, Fishes West. S. Amer., 1942: 333 (refs., range); Myers, Copeia, 1950: 64 



(synon.). 

 Neosteus altamazonica Norman, Ann. Mag. nat. Hist., (9) 11, 1923; 19 (ref., descr.). 

 Ilisha (Neosteus) altamazonica von Ihering, Rev. Indust. Anim., i (3), 1930: 230 (fin rays; note "Amazonas, 



rio Tocantins"). 

 Ilisha desuratus Nakashima, Bol. Mus. Hist. Nat., "Javier Prado," 5(16), 1941: 77, fig. (orig. descr.; type 



local., environs of Iquitos, Peruvian Amazon). 



Negative Reference: 



Ilisha altamazonica de Menezes (not of Cope). Publ. Serv. Piscic, Dep. Nac, Ceari, Brazil, 113, 1946: i 



(notes on common name; local, of coll., idem., etc. Later publication [113 A, 1947: l] refers this to 



synon. of /. castelnaeana). 



Ilisha castelnaeana (Cuvier and Valenciennes) 1847 

 Cagona, Apapa, Sardinha Grande, Pirapema, Gros Hareng 



Study Material. None. 

 Distinctive Characters. See Relationship. 



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

 after Norman (gg: 19), "three specimens 280 — 390 mm in length," presumably TL. 



Body: depth 33-3-37- 

 Head: length 26.5-27.5. 

 Anal fin: length of base 28-29. 



Scales: 63-66. 



Ventral scutes: 34-37. 



Fin rays: dorsal 19 or 20; anal 40 or 41, 



27* 



