elongatus, Cynolebias Steindachner [F.] 1881:98 [Anzeiger der Akademie der Wissenschaften in Wien, Mathematisch-Naturwissenschaftliche Klasse v. 18 (no. 11) (for 5 May 1881); ref. 20484] La Plata, Argentina. Holotype (unique): NMW 76518. Species described in more detail in Steindachner 1881:11 [ref. 14299]. •Valid as Cynolebias elongatus Steindachner 1881 -- (Costa 1995:78 [ref. 22097]). •Valid as Megalebias elongatus (Steindachner 1881) -- (Costa 1998:76 [ref. 23792], Lazara 2001:203 [ref. 25711], Costa 2002:917 [ref. 26505], López et al. 2002:61 [ref. 26808], Costa in Reis et al. 2003:531 [ref. 27061], López et al. 2003:69 [ref. 27366], Menni 2004:86 [ref. 28131]). •Valid as Austrolebias elongatus (Steindachner 1881) -- (Costa 2006:57 [ref. 28708], Costa 2009:188 [ref. 30417], Koerber 2011:7 [ref. 31122], Lanés et al. 2014:17 [ref. 33234], Koerber 2014:11 [ref. 33621], Litz & Koerber 2014:30 [ref. 33622], Mirande & Koerber 2015:51 [ref. 35117], Alonso et al. 2016:6 [ref. 34643], Calviño et al. 2016:9 [ref. 34699], Nión et al. 2016:42 [ref. 35565], Loureiro et al. 2018:11 [ref. 36240], Loureiro et al. 2023:170 [ref. 40506]). •Valid as Titanolebias elongatus (Steindachner 1881) -- (Alonso et al. 2023:12 [ref. 40292], Koerber et al. 2023:11 [ref. 40355], Koerber et al. 2023:4 [ref. 40368]). Current status: Valid as Titanolebias elongatus (Steindachner 1881). Rivulidae: Cynolebiinae. Distribution: South America: lower Río de la Plata basin (Argentina and Uruguay). Habitat: freshwater.