not a species from Argentina or Uruguay:
Scleronema operculatum Eigenmann, 1917

published in:
Ferrer, J. & L.R. Malabarba (2020):
Systematic revision of the Neotropical catfish genus Scleronema (Siluriformes: Trichomycteridae), with descriptions of six new species from Pampa grasslands.
Neotropical Ichthyology 18 (2): e190081

distribution (from publication):
Scleronema operculatum is endemic to the rio IbicuĂ­ basin, a tributary to the left bank of rio Uruguay, State of Rio Grande do Sul, southern Brazil.