Austrolebias nigrofasciatus Costa & Cheffe 2001

Two apomorphic color patterns, body bright gray with dark gray to black stripes in males (versus light gray or no stripes) and a vertically paired black blotch on caudal peduncle of juveniles and females (versus small spots irregularly arranged, or a single round dorsally positioned spot, or no spots on caudal peduncle). Males with light blue stripes parallel to rays on the basal half of unpaired fins and a black blotch anteriorly bordered by a narrow blue line on posterior portion of dorsal and anal fins. Scales on longitudinal series 26-28, supraorbital neuromasts 16-19, pharyngobranchial teeth 2-5. Dorsal fin origin anterior to anal fin origin in females. Caudal fin rounded.

Dorsal spines (total): 0; Dorsal soft rays (total): 16 - 23; Analspines: 0; Analsoft rays: 18 - 26; Vertebrae: 27 - 30