monstrosus, Cynolebias Huber [J. H.] 1995:9, Fig. 4, col. pl. (middle fig.) [Killi-Contact - Périodique bimestriel Spec. publ.; ref. 22880] Near La Serena, Boqueron Dept., 21.94°S, 56.97°W, Paraguay. Holotype: MNHN 1994-1110. Paratypes: ANSP 169973 (2), 169974 (orig. 2, now 1), 169975 (orig. 2, now 1); MNHN 1993-3619 [ex ANSP 169975] (1), 1994-1111 (1); MNHNP [ex ANSP 169974] (1); NMW 92899 (1); ZMA 121281 (3), 121284-85 (4, 2). Appeared as above first, then in Huber 1995 (Nov.):110, Figs. 9-12 [ref. 22204]. •Valid as Megalebias monstrosus (Huber 1995) -- (Costa 1998:76 [ref. 23792], Lazara 2001:204 [ref. 25711], Costa 2002:917 [ref. 26505], Costa in Reis et al. 2003:531 [ref. 27061], López et al. 2003:70 [ref. 27366], Menni 2004:86 [ref. 28131]). •Valid as Austrolebias monstrosus (Huber 1995) -- (Costa 2006:54 [ref. 28708], Koerber 2011:7 [ref. 31122], Lanés et al. 2014:17 [ref. 33234], Koerber 2014:11 [ref. 33621], Sarmiento et al. 2014:187 [ref. 35004], Mirande & Koerber 2015:51 [ref. 35117], Alonso et al. 2016:6 [ref. 34643], Koerber et al. 2017:70 [ref. 35267], Loureiro et al. 2018:11 [ref. 36240]). •Valid as Titanolebias monstrosus (Huber 1995) -- (Alonso et al. 2023:12 [ref. 40292], Koerber et al. 2023:4 [ref. 40368], Drawert 2023:17 [ref. 40730], Koerber 2024:6 [ref. 41228]). Current status: Valid as Titanolebias monstrosus (Huber 1995). Rivulidae: Cynolebiinae. Distribution: South America: semi-arid Chaco Region (Argentina, Paraguay and Bolivia). Habitat: freshwater.