A small, cone-toothed goodeid characterized with the following: divided preorbital and preopercular sensory canals and trophotaeniae in an elongated rosette; presence of pores 2b-4a in the supraorbital canal system; 12-18 narrow vertical bars along midside; 35-38 vertebrae; compared with A. dugesi more anal-fin rays, modally 14 (vs. 11 or 12

and more diploid chromosomes, 2N = 48 telocentrics and subtelocentrics (vs. 2N = 26 including 22 metacentrics); compared with A. maculata, more dorsal-fin rays, modally 16 (vs. 13 or 14) and in having mandibular pores 4 (vs. 0); compared with A. diazi, A. catarinae and A. meeki, it has fewer preopercular pores modally 8 (vs. 10 or 11), fewer preorbital pores modally 4 (vs. 5), absence of metacentric chromosomes, and a dark band on the male caudal fin (Ref. 58357).,

more dorsal