Apareiodon

1. Pre anus scales 29½ or more; premaxillary teeth with 12 to 15 cusps............................................................... A. affinis

1’. Pre anus scales 29 or less; premaxillary teeth with less than 12 cusps....................................................................... 2

2. Premaxillary teeth with cusps gradually decreasing in size, giving a cutting edge almost straight, with only the corners rounded; maxilla with two (rarely one) teeth........... ........................................................................ A. piracicabae

2’. Premaxillary teeth pointed, with cusps abruptally decreasing in size from the central to laterals; maxilla with one tooth................................................................... A. vladii