Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated Author Ota, Renata Rúbia Author Deprá, Gabriel de Carvalho Author Graça, Weferson Júnio da Author Pavanelli, Carla Simone text Neotropical Ichthyology 2018 2018-06-11 16 2 1 111 journal article 10.1590/1982-0224-20170094 f68fe85c-2a4c-4625-b684-74f61398d6c2 1982-0224 3678395 Megaleporinus piavussu ( Britski, Birindelli, Garavello, 2012 ) Fig. 5 Body elongated; greatest depth contained 2.8 to 3.5, caudal peduncle depth 7.9 to 9.1 times in SL; head length 3.5 to 4.7, predorsal distance 2.0 to 2.2, caudal peduncle length 7.5 to 8.7 in SL; snout length 2.1 to 2.7, horizontal orbital diameter 3.7 to 5.1 and least interorbital width 1.9 to 2.4. Mouth subterminal; premaxilla and dentary with 3 teeth, no maxillary teeth. Lateral line with 41-44 pored scales; transverse series above lateral line with 6 or 7 scale rows and below with 5 or 6 scale rows. Dorsal fin with 11 or 12, pectoral fin with 15-19, pelvic fin with 9 and caudal fin with 19 rays ( Britski et al. , 2012 ). Ground color silvery; three dark-brown rounded blotches over lateral line. Dorsal fin whitish; pectoral, pelvic, anal and caudal fins yellowish. Maximum standard length. 410.0 mm. Distribution. Upper rio Paraná basin. Remarks. Megaleporinus piavussu was identified as L. obtusidens by Graça, Pavanelli (2007) . Ramirez et al. (2016) described the new genus, Megaleporinus , and proposed the new combination. Britski et al. (2012) redescribed M. obtusidens and described the new species, M. piavussu (under Leporinus ) from the upper rio Paraná basin. Megaleporinus piavussu can be distinguished by having 39 or 40, rarely 41, pored scales in the lateral line, and mouth terminal, except in some large adults with somewhat subterminal mouth ( vs. 41 to 43, rarely 44 in M. obtusidens , and mouth directed somewhat or entirely downward in M. obtusidens ). The epithet piavussu is similar to the common name of M. macrocephalus “ piavuçu, piaussu ”, but these are different species and should not be confused.