affinis, Cynolebias Amato [L. H.] 1986:6, Pl. 3 (figs. 5-6) [Comunicaciones Zoologicas del Museo de Historia Natural de Montevideo v. 11 (no. 162); ref. 9170] Floodlands of Tres Cruces Creek, route 5, kilometers 399.5, Tacuarembó, Uruguay. Holotype: MHNM 2468. Paratypes: MHNM 2469-73 (1, 86, 212, 1, 2); MZUSP 36448-49 (1, 1). Type catalog: Loureiro et al. 2016:412 [ref. 35150]. •Valid as Cynolebias affinis Amato 1986 -- (Costa 1995:65 [ref. 22097], Murphy & Collier 1997:797 [ref. 25585], Costa 1999:301 [ref. 24229], Costa 1999:93 [ref. 24131]). •Valid as Austrolebias affinis (Amato 1986) -- (Costa 1998:75 [ref. 23792], Lazara 2001:59 [ref. 25711], Costa 2002:917 [ref. 26505], Costa in Reis et al. 2003:527 [ref. 27061], Perujo et al. 2005:3 [ref. 28452], Costa 2006:71 [ref. 28708], Costa 2009:188 [ref. 30417], Litz & Koerber 2014:29 [ref. 33622], Koerber & Litz 2014:5 [ref. 34967], Koerber & Litz 2016:7 [ref. 35098], Nión et al. 2016:42 [ref. 35565], Loureiro et al. 2018:11 [ref. 36240], Koerber et al. 2020:8 [ref. 37480], Koerber et al. 2021:9 [ref. 38894], Loureiro et al. 2023:166 [ref. 40506]). •Valid as Matilebias affinis (Amato 1986) -- (Alonso et al. 2023:9 [ref. 40292], Koerber et al. 2023:11 [ref. 40355]). Current status: Valid as Matilebias affinis (Amato 1986). Rivulidae: Cynolebiinae. Distribution: South America: Negro River basin (Uruguay). Habitat: freshwater.