Hypostomus microstomus Weber, 1987

Fig. 24

Body deep; greatest body depth contained 4.0 to 4.7 and caudal peduncle depth 8.4 to 9.4 times in SL; head length 2.8 to 3.2, predorsal distance 2.4 to 2.5, dorsal-fin spine length 2.6 to 3.2, pectoral-fin spine length 2.8 to 3.1, adipose-fin spine length 13.5 to 6.0 and caudal peduncle length 3.0 to 3.5 in SL; snout length 1.4 to 1.6, horizontal orbital diameter 4.6 to 5.8 and least interorbital width 1.6 to 2.1 in HL. Mouth inferior; premaxilla with 8-14 and dentary with 10-16 teeth. Mid-lateral series with 24-27, predorsal series with 3, and dorsal-fin base series with 7 plates. Dorsal fin with I,7, pectoral fin with I,6, pelvic fin with i,5 and anal fin with 6 rays (Weber, 1987). Ground color brown; scattered light-beige spot on body. Brown fins with light-beige spots, sometimes inconspicuous.

Maximum standard length. 300.0 mm (Graça, Pavanelli, 2007).

Distribution. Río Paraná basin.

Remarks. Hypostomus microstomus 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.