Apteronotus aff. albifrons (Linnaeus, 1766)

Fig. 16

Body elongated and compressed; greatest depth contained 5.5 to 6.2 times in TL; head length 5.5 to 6.0, anal-fin base length 1.2 to 1.5, caudal-peduncle length 5.0 to 6.6, preanal distance 6.1 to 7.5 and prepectoral distance 5.5 to 6.0 in LEA; snout length 2.7 to 4.7, horizontal orbital diameter 9.0 to 16.7 and least interorbital width 3.9 to 4.7 in HL. Mouth terminal. Pectoral fin with 15-16, anal fin with 170-192 and caudal fin with 17 to 20 rays. Transversal series above lateral line with 15-16 scale rows (Campo-da- Paz, 1997). Ground color dark-brown, with brownish-white middorsal stripe from tip of lower jaw to nape, continuing as narrower line until about middle of body (occasionally faded or discontinuous); region around branchial aperture, including isthmus, brownish-white; wide brownish-white transverse bar across tail and posterior portion of anal fin; narrower brownish-white transverse bar across posterior portion of caudal peduncle and caudal-fin base. Distal portion of caudal fin brownish white; fins otherwise darkbrown (Graça, Pavanelli, 2007).

Maximum total length. 150.0 mm (Graça, Pavanelli, 2007).

Distribution. Drainages from Venezuela to Paraguay and río Paraná basin.