Apteronotus acidops Triques, 2011

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 : 54

Apteronotus acidops Triques, 2011

Fig. 16

Body elongated and compressed; greatest depth contained 6.6 to 8.0 times in TL; head length 3.8 to 5.6, anal-fin base length 1.2, caudal-peduncle length 7.3 to 7.5, preanal distance 5.2 to 7.0 and prepectoral distance 4.2 to 5.2 in LEA; snout length 1.6 to 2.2, horizontal orbital diameter 12.5 to 13.2 and least interorbital width 6.2 in HL. Mouth terminal. Pectoral fin with 13-18 rays, anal fin with 162-220 rays and caudal fin with 17-20 rays; transverse series above lateral line with 11-15 scale rows ( Graça, Pavanelli, 2007; Triques, 2011). Ground color dark-brown dorsally, and pale yellow ventrally; posterior portion of caudal peduncle and caudal-fin base with lightbeige blotch. Caudal fin dark-brown.

Maximum total length. 325.0 mm.

Distribution. Upper rio Paraná basin.

Remarks. Apteronotus acidops was identified as Apteronotus sp. by Graça, Pavanelli (2007). Triques (2011) described the new species from the upper rio Paraná basin. It is noteworthy, however, that not all specimens present the extremely elongate snout characteristic of A. acidops . R. Campos-da-Paz (in an e-mail, rcamposdapaz@gmail. com, August 2016) re-analyzed the specimen depicted by Graça, Pavanelli (2007: 191; wrongly referenced as NUP 1750, in fact NUP 2701) and confirmed it as A. acidops . This specimen and another (NUP 2978) are typically long snouted. In contrast, some other specimens present morphometric values that are apparently intermediate between A. acidops and A. brasiliensis (see Triques, 2011). Rather than admitting the existence of both species in the upper rio Paraná floodplain, the range of some morphometric values in A. acidops is considered slightly wider than that reported by Triques (2011) and overlaps in part those of A. brasiliensis .

Figures

Fig. 16. a. Apteronotus acidops, NUP 1750, 240.0 mm TL, Itaipu Reservoir, Guaíra, State of Paraná. b. Apteronotus aff. albifrons, 100.0 mm TL, uncat. c. Apteronotus cf. caudimaculosus, 260.0 mm TL, uncat. d. Apteronotus ellisi, 128.2 mm TL, uncat. e. Sternarchorhynchus britskii, 212.0 mm TL, uncat. f. Gymnotus inaequilabiatus, 238.0 mm TL, uncat. g. Gymnotus pantanal, NUP 13328, 138.6 mm SL, ribeirão Jacutinga, São Jorge do Ivaí, State of Paraná. h. Gymnotus paraguensis, 250.0 mm TL, uncat. i. Gymnotus sylvius, MZUSP 83538, paratype, 260.0 mm TL, rio Ribeira de Iguape, next to Miracatu, Miracatu, State of São Paulo.