Fig. 13

Body elongated; greatest body depth contained 3.7 to 4.8 and caudal peduncle depth 10.0 to 12.8 times in SL; head length 3.6 to 4.6, predorsal distance 2.2to 2.4 and caudal peduncle length 6.0 to 7.2 in SL; snout length 3.0 to 3.6, horizontal orbital diameter 3.2 to 4.0 and least interorbital width 2.0 to 3.2 in HL. Mouth terminal; premaxilla with 9, dentary and maxilla with no teeth. Lateral line with 85-97 pored scales; transverse series above lateral line with 18-21 scale rows and below with 8-11 scale rows. Dorsal fin with 11 or 12, pectoral fin with 16-18, pelvic fin and anal fin with 10 or 11 and caudal fin with 19 rays. Ground color silvery; black rounded or oval, horizontally elongated, blotch approximately on vertical through end of dorsal fin. Hyaline fins, except caudal fin, with dark-brown oblique stripe on each lobe (Graça, Pavanelli, 2007).

Maximum standard length. 230.0 mm (Graça, Pavanelli, 2007).

Distribution. Paraná-Paraguay system.

Remarks. Hemiodus orthonops is a non-native species from the upper rio Paraná and its 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).