Papiliolebias hatinne sp. n. is described from a temporary pond, 5 km north of Embarcación, in the río Bermejo basin, Province of Salta, Argentina. Papiliolebias hatinne sp. n. is distinguished from the only congener, P bitteri, from the río Paraguay basin, by a combination of characters: 26-28 vertebrae, with 8-10 being precaudal: second proximal radial of anal fin located between vertebrae 9 and 10 or 10 and 11: 1-2 vomerine teeth: an elongation of jaw suspensorium: first epibranchial somewhat triangular: 7-8 pelvic-fin rays: 12- 13 pectoralfin rays: 20-23 caudal-fin rays: males with anal fin turquoise blue, dorsal and caudal fins bluish. pelvic fin blue, and humeral spot metallic bluish green; females without dark dots on flanks. The chromosome formula is 2n= 28. the FN= 36, integrated by two pairs of metacentric, two pairs of submetacentric and ten pairs of subtelocentric chromosomes.