Astyanax
1. A well-defined black, horizontally elongate humeral spot, overlapped by a more diffuse, vertically elongate grey stripe and followed by a second diffuse, vertically elongate grey stripe ............................................. A. lacustris
1’. One or two relatively diffuse, grey to brown vertically elongate humeral spots........................................................ 2
2. One humeral spot ............................................................ 3
2’. Two humeral spots......................................................... 4
3. Anal fin with 29 to 35 branched rays ............. A. schubarti
3’. Anal fin with 24 to 28 branched rays ...... A. aff. fasciatus
4. Anal-fin origin anterior to vertical through the end of dorsal fin.................................................................. A. biotae
4’. Anal-fin origin posterior to vertical through the end of dorsal fin.............................................................................. 5
5. Greatest body depth on vertical through the middle of pectoral fin .................................................... A. aff. paranae
5’. Greatest body depth two scales anterior to the dorsalfin origin.......................................................... A. bockmanni