Astyanax dissimilis Garavello & Sampaio 2010

This species is distinguished from all its congeners from the Iguaçu basin by the following set of characters: infraorbital 3 not in contact with pre-opercle, leaving a naked area corresponding to approximately 1/5-1/4 the height of infraorbital 3; premaxillary external series with 2-5, usually 4 tricuspid teeth; non-symphysal teeth in premaxillary internal series with 5 cusps forming an arch in ventral view; maxillary with 0-3, usually 1 tooth; faint, narrow and elongate vertical humeral bar present (Ref. 85756).

Dorsal soft rays (total): 8 - 9; Analsoft rays: 16 - 21