not a species from Argentina:
Platydoras costatus (Linneaus, 1758)
remarks (from publication):
p. 482: Examination of extant types and ongoing studies by the two junior authors (MAH, MHSP) confirm the distinctiveness of three nominal species of Platydoras: P. armatulus (Paraguay-Paraná and portions of Amazon and Orinoco basins), P. costatus (Corantijn and Maroni basins), and P. hancockii (Negro, Essequibo, Demerara, and upper Orinoco basins).
p. 489: Platydoras costatus has long been misunderstood despite the early illustrations of Gronow’s type specimen (Pl. 5, figs. 1 and 2 in Gronovius, 1756) upon which Linnaeus (1758) based this name. Gronow’s (Gronovius, 1756) illustration depicts a Platydoras with dorsal head and midlateral scutes uniformly colored. Platydoras costatus, however, is often applied to specimens with a distinct, continuous light midlateral stripe (white to yellow in life) that converges dorsoanteriorly with its pair in the interorbital region. Based on our examination of Platydoras from throughout its wide range, only specimens from coastal drainages of Suriname and French Guiana (i.e., Corantijn, Suriname, Maroni) lack a distinct light stripe on the head and sides, evidence that the types of P. costatus originated from this region.
Piorski, N.M., J.C. Garavello, M. Arce & M.H. Sabaj Pérez (2008):
Platydoras brachylecis, a new species of thorny catfish (Siluriformes: Doradidae) from northeastern Brazil.
Neotropical Ichthyology 6 (3): 481-494