Moenkhausia sanctaefilomenae (Steindachner, 1907) Fig. 8

Body deep; greatest depth contained 2.4 to 2.8 and caudal peduncle depth 8.0 to 9.2 times in SL; head length 3.7 to 3.9, predorsal distance 1.7 to 1.9 and caudal peduncle length 11.8 to 13.0 in SL; snout length 2.9 to 3.7, horizontal orbital diameter 2.4 to 3.0 and least interorbital width 2.3 to 2.9 in HL. Mouth terminal; inner row of premaxilla with 5 teeth, outer with 4-5, dentary with 9-11 and maxilla with 1-2 teeth. Lateral line incomplete, with 7-11 pored scales; longitudinal series with 25-29 scales; transverse series above lateral line with 4 scale rows and below with 3 scale rows. Dorsal fin with 10-11, pectoral fin with 14-15, pelvic fin with 9, anal fin with 24 to 26 and caudal fin with 19 rays (Graça, Pavanelli, 2007). Ground color silvery; superior portion of eye red; darkbrown chromatophores concentrated on distal margin of scales conferring reticulated pattern to body; one darkbrown humeral spot; anterior half of caudal peduncle with light-beige area. Yellowish fins; posterior portion of caudal peduncle and proximal third of caudal fin with conspicuous black transverse bar occupying their whole depth.

Maximum standard length. 54.0 mm (Graça, Pavanelli, 2007).

Distribution. Rio Parnaíba, rio São Francisco and río de la Plata basins.