Hypophthalmus oremaculatus Nani, Fuster, 1947

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 : 81-82

Hypophthalmus oremaculatus Nani, Fuster, 1947

Fig. 28

Body elongate; greatest body depth contained 4.3 to 4.4, head depth 7.5 to 7.9, caudal-peduncle depth 11.8 to 12.0 times in SL; head length 4.1 to 4.3, anal-fin base length 2.0 to 2.2, adipose-fin base length 31.0 to 34.2, and maxillarybarbel length 3.6 to 4.2 in SL; snout length 2.0 to 2.2, horizontal orbital diameter 7.7 to 8.6, and least interorbital width 2.2 to 2.3 in HL. Mouth terminal; toothless. Dorsal fin with 7, pectoral fin with 16-18, pelvic fin with 7 and anal fin with 55-62 rays. Ground color greyish dorsally, whitish ventrally. Whitish fins with dark-grey margins.

Maximum standard length. 440.0 mm.

Distribution. Río Paraná basin.

Remarks. Hypophthalmus oremaculatus was identified as H. edentatus by Graça, Pavanelli (2007). Littmann et al. (2015) redescribed H. oremaculatus , provided additional information on H. edentatus and proposed the new identification for the specimens from the río Paraná basin. Additionally, the same authors found an exceptional specimen in a tributary of the rio Paraná (NUP 1730) that matches the description of a new species (identified as Hypophthalmus cf. n. sp. 1, Littmann, Lundberg, in preparation) by having 61 total vertebrae, seven post-Weberian vertebrae, mental barbels not reaching pectoral fins, and dorsal-fin origin posterior to anal-fin origin (vs. 55 to 59 total vertebrae, 3 to 6 post-Weberian vertebrae, long mental barbels, extending to pectoral-fin origin or beyond, and dorsalfin origin approximately on vertical through anal-fin origin, in H. oremaculatus ). However, the new species is from the rio Orinoco and Amazon basins, and, at this moment, Littmann et al. (2015) only speculated that this specimen is possible a phenotypic outlier of H. oremaculatus , or a geographic outlier of Hypophthalmus n. sp. 1. Nevertheless, H. oremaculatus 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.

Figures

Fig. 28. a. Hemisorubim platyrhynchos, 470.0 mm SL, fresh specimen, uncat. b. Hypophthalmus oremaculatus, 405.0 mm SL, fresh specimen, uncat. c. Iheringichthys labrosus, 200.0 mm SL, uncat. d. Megalonema platanum, 340.0 mm SL, fresh specimen, uncat.