petenensis, Poecilia Günther [A.] 1866:342 [Catalogue of the fishes in the British Museum v. 6; ref. 1983] Lake Petén, Guatemala. Lectotype: BMNH 1864.1.26.377. Paralectotypes: (at least 4) BMNH 1864.1.26.375 (1), 1864.1.26.379 (2), 2004.12.1.1-2 [ex BMNH 1864.1.26.377] (2), 2008.5.27.2 (1, skeleton). Subjectively invalid; secondarily preoccupied by Mollienisia petenensis Günther 1866, replaced by Mollienesia gracilis Regan 1913. Mollienesia gracilis itself is subjectively invalid; preoccupied by Poecilia gracilis Valenciennes 1846 (see Greenfield 1990:452 [ref. 16548]). Lectotype selected by Poeser 2002:243 [ref. 26215]. On the basis of Art. 59.4, Poecilia petenensis Günther 1866 can be retained. •Synonym of Poecilia sphenops Valenciennes 1846 -- (Rosen & Bailey 1963:49 [ref. 7067]). •Valid as Poecilia petenensis Günther 1866 -- (Rosen & Bailey 1963:55 [ref. 7067], Greenfield 1990:450 [ref. 16548], Espinosa Pérez et al. 1993:50 [ref. 22290], Greenfield & Thomerson 1997:125 [ref. 22947], Rodriguez 1997:673 [ref. 23266], Fuller et al. 1999:312 [ref. 25838], Meyer & Radda 2000:75 [ref. 25029], Poeser 2002:245 [ref. 26215], Meyer et al. 2002:50 [ref. 26721], Poeser 2003:159 [ref. 26783], Ghedotti & Wiley 2003:1157 [ref. 27019], Lucinda in Reis et al. 2003:568 [ref. 27061], Nelson et al. 2004:104 [ref. 27807], Meyer et al. 2004:150 [ref. 28000], Lucinda & Reis 2005:45 [ref. 29205], Miller 2006:238 [ref. 28615], Scharpf 2007:17 [ref. 30398], Poeser 2011:420 [ref. 31550], Page et al. 2013:110 [ref. 32708], Barrientos et al. 2015:4 [ref. 37653], Meyer 2015:244 [ref. 34698], Palacios et al. 2016:232 [ref. 34629] in subgenus Mollienesia, Huber 2019:114 [ref. 36941], Barrientos et al. 2023:274 [ref. 41235], Quintana 2024:8 [ref. 41186]). Current status: Valid as Poecilia petenensis Günther 1866. Poeciliidae: Poeciliinae. Distribution: Central America: Lake Petén area (Guatemala) endemic. Habitat: freshwater.