considered a valid species from Argentina:
Apistogramma trifasciata (Eigenmann & Kennedy, 1903)

remarks:
López, Miquelarena & Ponte Gómez (2005) list Apistogramma trifasciata from the río Paraná basin in the provinces of Misiones and Corrientes, and the Uruguay and Riachuelo basins in Corrientes. López et al. (2003) consider A. trifasciata not from Argentina but ‘especie limítrofe’, meaning ‘species from neighbouring countries. Earlier López et al. (1987) had stated that A. trifasciatum was ‘probablemente limítrofe’. Due to the southern locality for a species of Apistogramma possibly the record of A. trifasciata by Bonetto et al. (1970) from the laguna Tacuaral, some 70 km N of the city of Santa Fé, was not taken seriously.
As a matter of fact the presence of this species in freshwater of Argentina is well known to aquarium hobbyists, e.g. Staeck (1999) from a pond 30 km N San Roque in Corrientes and Puentes (http://www.cichlidae.com/gallery/picture.php?p=477) from río Pilcomayo in Formosa.
Recently A. trifasciata was listed by Kullander (2003) for Argentina, Brazil and Paraguay.

type locality:
arroyo Chagalalina, Paraguay

distribution in Argentina:
– Esteros del Riachuelo in Corrientes
– affluents of río Paraná in Misiones
– affluents of río Uruguay in Corrintes
– río Pilcomayo basin in Formosa

published in:
López, H.L., A.M. Miquelarena & J. Ponte Gómez (2005):
Biodiversidad y Distribución de la Ictiofauna Mesopotámica.
INSUGEO, Miscelánea 14: 311 – 354
in: Aceñolaza, F.D. (ed.)
Temas de la Biodiversidad del Litoral fluvial argentino II, Tucumán

other references:
Bonetto, A.A., E. Cordiviola de Yuan & C. Pignalberi (1970):
Nuevos datos sobre poblaciones de peces en ambientes leníticos permanentes del Paraná medio.
Physis Buenos Aires 30 (80): 141-154

Kullander, S.O. (2003):
Family Cichlidae (Cichlids).
in: Reis, R. E., S. O. Kullander and C. J. Ferraris, Jr.
Check list of the freshwater fishes of South and Central America.
Edipucrs, PortoAlegre, 729 pp.

Staeck, W. (1999):
Ein Zwergbuntbarsch aus den Subtropen: Apistogramma borellii (Regan, 1906).
Aquarium heute 17 (19: 248-252.

López et al. 1987 + 2003 > literature