Brycon orbignyanus (Valenciennes, 1850)

Fig. 6

Body deep; greatest depth contained 2.8 to 3.4, caudal peduncle depth 9.2 to 11.7 times in SL; head length 3.3 to 5.1, predorsal distance 1.8 to 2.1, caudal peduncle length 5.3 to 7.8 in SL; snout length 2.7 to 3.6, horizontal orbital diameter 3.1 to 5.0 and least interorbital width 2.1 to 3.0 in HL. Mouth terminal; median row of premaxilla with 2-4, inner row with 5-9, outer row with 9-13, inner row of dentary with 4, outer row 8-14 and maxilla with 11-20 teeth. Lateral line with 52-63 pored scales; transverse series above lateral line with 10-13 scale rows and below with 5-9 scale rows. Dorsal fin with 11, pectoral fin with 13-16, pelvic fin with 7 or 8, anal fin with 24-30 and caudal fin with 19 rays (Lima, 2017). Ground color silvery; dark-brown transverse band on caudal peduncle, extending to distal margin of median caudal-fin rays; black transverse humeral blotch, sometimes inconspicuous. Pelvic, anal and caudal fins reddish; dorsal and pectoral hyaline or grey (Graça, Pavanelli, 2007).

Maximum standard length. 400.0 mm (Graça, Pavanelli, 2007).

Distribution. Río Paraná and Uruguay basins.