Do we know what we are conserving? Fishes from Parque Nacional Aconquija, Tucumán, Northwestern Argentina Author Saravia, Alejandro Nicolás Author Mettola, Víctor Ezequiel Author Aguilera, Gastón Author Cano, Paula Daniela Author Terán, Guillermo Enrique text Acta Zoológica Lilloana 2023 2023-12-07 67 2 327 347 http://dx.doi.org/10.30550/j.azl/1804 journal article 299024 10.30550/j.azl/1804 23b81975-ae39-472d-828b-baaac3cb0956 1852-6098 11645144 Astyanax lacustris (Lütken 1875) Material examined. 1 exemplar; 53.5 mm SL. CI FML 7928 , 1 ex, 27°12’ 36.21”S ; 65°37’ 22.80”W Pueblo Viejo River . Identification. Complete lateral line; perforated scales on lateral lines 30–39 (rarely 40 or 41); naked caudal fin; presence of two series of teeth in the premaxilla with 5 teeth in the inner series; maxilla without maxillary teeth; dorsal fin with 9 branched rays; anal fin with 28-30 rays; dark horizontal humeral spot ( Lucena and Soares, 2016 ).