viedmensis, Diplomystes MacDonagh [E. J.] 1931:65 [Notas Preliminares del Museo de La Plata v. 1; ref. 16301] Río Negro, vicinity of Viedma, Province of Río Negro, Argentina. Holotype: MLP 214 [ex 19-III-31.3]. Paratypes: MLP 8966 [ex MCILP 19-III-31-1] (1); ?MCLIP 19-III-31-2 (1). Type catalog: Ferraris 2007:166 [ref. 29155], Miquelarena & Nadalin 2014:10 [ref. 33466]. •Valid as Olivaichthys viedmensis (MacDonagh 1931) -- (de Pinna 1998:291 [ref. 23847] on Arratia 1987, Ferraris in Reis et al. 2003:256 [ref. 27061], López et al. 2003:37 [ref. 27366], Ferraris 2007:166 [ref. 29155], Arratia & Quezada-Romegialli 2017:6 [ref. 35155]). •Valid as Diplomystes viedmensis MacDonagh 1931 -- (Arratia 1987:68 [ref. 5957], Burgess 1989:25 [ref. 12860], Azpelicueta 1994:224 [ref. 22312], Azpelicueta 1994:12 [ref. 22377], Azpelicueta & Gosztonyi 1998:901 [ref. 25377], López et al. 2002:60 [ref. 26808], Lundberg et al. 2004:72 [ref. 27673], Menni 2004:79 [ref. 28131], Muñoz-Ramírez et al. 2014:146 [ref. 33192], Mirande & Koerber 2015:28 [ref. 35117], Muñoz-Ramírez et al. 2023:8 [ref. 40526]). Current status: Valid as Diplomystes viedmensis MacDonagh 1931. Diplomystidae. Distribution: South America: Negro River basin, Argentina and Chile. Habitat: freshwater.