Fig. 3

Body elongated; greatest depth contained 3.6 to 4.8 and caudal peduncle depth 12.1 to 14.9 times in SL; head length 3.0 to 3.6, predorsal distance 1.5 to 1.8 and caudal peduncle length 9.8 to 13.1 in SL; snout length 2.8 to 3.3, horizontal orbital diameter 3.5 to 5.0 and least interorbital width 3.5 to 4.6 in HL. Mouth terminal; outer row of premaxilla with 13- 16 and inner row with 10-20, and maxilla with 16-39 teeth. Lateral line complete, with 93-108 pored scales; transverse series above lateral line with 26-30 scale rows and below with 15-17 scale rows. Dorsal fin with 11, pectoral fin with 14-18, pelvic fin with 8, anal fin with 23-27, and caudal fin with 19 rays. Ground color silvery to yellowish; black rounded humeral blotch; black oval, horizontally elongated, blotch on caudal-fin base, extending to median caudal-fin rays. Yellowish fins; anal and pectoral fin with distal margins black (Graça, Pavanelli, 2007).

Maximum standard length. 180.0 mm (Graça, Pavanelli, 2007).

Distribution. Río de la Plata and rio Mamoré basins.

Remarks. Acestrorhynchus pantaneiro is a non-native species from the upper rio Paraná basin, and its recent occurrence can be associated with the functioning of the Canal da Piracema, a fish ladder that connects the region downstream from the Itaipu Dam to the region upstream from the dam (Graça, Pavanelli, 2007).