Megalonema platanum (Günther, 1880)

Fig. 28

Body elongate; greatest body depth contained 5.3 to 5.7, head depth 6.9 to 7.9, caudal peduncle depth 12.9 to 13.2 times in SL; head length 3.7 to 3.9, anal-fin base length 10.6 to 11.5, adipose-fin base length 4.3 to 4.5, and maxillarybarbel 1.3 to 1.8 in SL; snout length 2.0 to 2.2, horizontal orbital diameter 4.5 to 5.0 and least interorbital width 4.5 to 4.7 in HL. Mouth terminal; dentigerous tooth plates present in both premaxilla and dentary. Dorsal fin with 7, pectoral fin with 14 or 15, pelvic fin with 7, and anal fin with 9 or 10 rays. Ground color light-grey. Yellowish or hyaline fins (Graça, Pavanelli, 2007).

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

Distribution. Paraná-Paraguay system.