ibicuiensis, Cynolebias Costa [W. J. E. M.] 1999:93, Figs. 1-2 [Revue française d'Aquariologie Herpétologie v. 25 (no. 3/4) [for 1998]; ref. 24131] Rio Ibicui-Mirim, rio Ibicui drainage, road BR-287 between São Pedro do Sul and Santa Maria, Rio Grande do Sul, Brazil. Holotype: MCP 10201. Paratypes: MCP 21171 (1). •Valid as Austrolebias ibicuiensis (Costa 1999) -- (Lazara 2001:61 [ref. 25711], Costa 2002:917 [ref. 26505], Costa in Reis et al. 2003:527 [ref. 27061], Costa 2006:64 [ref. 28708], Bertaco et al. 2016:424 [ref. 34561], Volcan et al. 2017:150 [ref. 35644], Loureiro et al. 2018:11 [ref. 36240]). •Valid as Matilebias ibicuiensis (Costa 1999) -- (Alonso et al. 2023:9 [ref. 40292]). Current status: Valid as Matilebias ibicuiensis (Costa 1999). Rivulidae: Cynolebiinae. Distribution: South America: upper Uruguay River basin, southern Brazil. Habitat: freshwater.