Key to species of Harttia from the rio São Francisco basin

1a. Canal plate and preanal plates present ........................................................................2

1b. Canal plate and preanal plates absent.......................................................................... 4

2a. Abdomen region between pectoral- and pelvic-fin girdles naked; anal-fin size equivalent in males and females (respectively, 11.7–18.2% and 11.7–18.7% of SL)..................................................... 3

2b. Abdomen region between pectoral- and pelvic-fin girdles partially covered by plates; anal-fin size in adult males longer than in females, respectively 20–25% and 13.9–16.1% of SL .............................................................................. H. longipinna

3a. Two to four small and circular pre-anal plates; dorsal-fin spinelet absent ....................................................................................................... H. torrenticola

3b. Two large and trapezoidal pre-anal plates, sometimes with small plates around them; dorsal-fin spinelet present.................................................................. H. canastra

4a. Thoracic plates absent; five infraorbital plates; seven branched rays on the pectoral fin ................................................................................................. H. leiopleura

4b. Three to five thoracic plates; six infraorbital plates; six branched rays on the pectoral fin ............................................................................................. H. novalimensis