Platydoras armatulus (Valenciennes, 1840)

Fig. 20

Body deep; greatest body depth contained 3.2 to 3.9, head length 3.8 to 4.0 times in SL; snout length contained 2.2 to 2.3, horizontal orbital diameter 4.8 to 5.5 and least interorbital width 2.5 to 2.7 times in HL; orbital diameter contained 1.8 to 2.1 times in interorbital width. Mouth terminal; with dentigerous plates in both premaxilla and dentary. Lateral line with 27-28 plates. Dorsal fin with I,6, pectoral fin with I,7, pelvic fin with 7 and anal fin with 10-12 rays (Graça, Pavanelli, 2007). Ground color darkbrown above pelvic-fin orign, whitish to yellowish below; yellowish longitudinal band, from dorsal region of head to distal margin of median caudal-fin rays. Dorsal, pelvic, anal and caudal fins hyaline or light-beige; dorsal fin with dark-brown blotch on distal margin; pectoral fin darkbrown, its spine light-beige; caudal fin with one dark-brown longitudinal band on each lobe.

Maximum standard length. 178.0 mm (Graça, Pavanelli, 2007).

Distribution. Paraná-Paraguay system.

Remarks. Platydoras armatulus 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.