Megaleporinus obtusidens (Valenciennes, 1836)

Ota, Renata Rúbia, Deprá, Gabriel de Carvalho, Graça, Weferson Júnio da & Pavanelli, Carla Simone, 2018, Peixes da planície de inundação do alto rio Paraná e áreas adjacentes: revised, annotated and updated, Neotropical Ichthyology 16 (2), pp. 1-111 : 21-22

Megaleporinus obtusidens (Valenciennes, 1836)

Fig. 5

Body elongated; greatest depth contained 3.2 to 3.5, caudal peduncle depth 8.6 to 8.9 times in SL; head length 3.2 to 3.8, predorsal distance 2.0 to 2.1, caudal peduncle length 7.0 to 7.9 in SL; snout length 2.0 to 2.2, horizontal orbital diameter 2.9 to 3.8 and least interorbital width 6.7 to 8.4 in HL. 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 6 scale rows. Dorsal fin with 12, pectoral fin with 17, pelvic fin with 9, anal fin with 9 or 10 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 ( Graça, Pavanelli, 2007).

Maximum standard length. 350 mm ( Graça, Pavanelli, 2007).

Distribution. Río de la Plata basin, Laguna dos Patos drainage, rio Parnaíba and rio São Francisco basins.

Remarks. Megaleporinus obtusidens was identified as Leporinus elongatus by Graça, Pavanelli (2007). Ramirez et al. (2016) described the new genus, Megaleporinus , and proposed the new combination. Britski et al. (2012) redescribed Megaleporinus elongatus and M. obtusidens (under Leporinus ), distinguishing them by the number of circumpeduncular scale rows (12 in M. elongatus ; 16 in M. obtusidens ), and restricting the distribution of M. elongatus to the rio Jequitinhonha and rio Pardo. In turn, the specimens identified as Leporinus obtusidens by Graça, Pavanelli (2007) belong to Megaleporinus piavussu , a species endemic to the upper rio Paraná basin.

Figures

Fig. 5. a. Megaleporinus macrocephalus, NUP 1838, 470.0 mm SL, rio Chopim, Cruzeiro do Iguaçu, State of Paraná. b. Megaleporinus obtusidens, 190.8 mm SL, fresh specimen, uncat. c. Megaleporinus piavussu, 148.9 mm SL, fresh specimen, uncat. d. Schizodon altoparanae, MZUSP 41102, holotype, 282.2 mm SL, rio Paraná, in front of Jupiá, Três Lagoas, State of Mato Grosso do Sul. e. Schizodon borellii, 207.5 mm SL, fresh specimen, uncat. f. Schizodon nasutus, NUP 2495, 160.0 mm SL, Itaipu Reservoir, Santa Helena, State of Paraná.