Heptapterus mustelinus (Valenciennes, 1835)

Fig. 21

Body elongated; greatest body depth contained 10.0 to 10.6, head depth 11.9 to 12.2 and caudal peduncle depth 17.7 to 18.4 times in SL; head length 6.1 to 6.4, anal-fin base length 4.9 to 5.5, adipose-fin base length 2.0 to 2.2 and maxillary-barbel length 6.0 to 7.2 times in SL; snout length 2.9 to 3.1, horizontal orbital diameter 4.9 to 5.2 and least interorbital width 3.7 to 3.9 times in HL. Mouth terminal; premaxilla and dentary with several diminute and viliform teeth. Dorsal fin with 7, pectoral fin with 6-9, pelvic fin with 6 and anal fin with 15-17 rays. Ground color dark-brown; dark-brown transverse bars on dorsum. Hyaline or lightbeige fins (Graça, Pavanelli, 2007).

Maximum standard length. 130.0 mm (Graça, Pavanelli, 2007).

Distribution. Río de la Plata basin and costal drainages of Southern Brazil.

Coments. Heptapterus mustelinus is a non-native species from the upper rio Paraná, and its occurrence can be associated with the filling of the Itaipu Reservoir and the consequent inundation of the Sete Quedas Falls (Langeani et al., 2007).