gracilis, Mollienesia Regan [C. T.] 1913:1012 [Proceedings of the Zoological Society of London 1913 (pt 4) (art. 58); ref. 3653] Lake Petén [Petén Itza], Guatemala. Lectotype: BMNH 1864.1.26.377. Paralectotypes: 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). Replacement name for Poecilia petenensis Günther 1866, preoccupied by Mollienisia petenensis Günther 1866. Mollienesia gracilis itself is secondarily preoccupied by Poecilia gracilis Valenciennes 1846 (see Greenfield 1990:452 [ref. 16548]). Lectotype selected for Poecilia petenensis Günther 1866 by Poeser 2002:243 [ref. 26215]. Poecilia petenensis Günther 1866 is treated as valid on the basis of Art. 59.4. •Synonym of Poecilia sphenops Valenciennes 1846 -- (Rosen & Bailey 1963:52 [ref. 7067], Lucinda in Reis et al. 2003:569 [ref. 27061]). •Valid as Poecilia gracilis (Regan 1913) -- (Meyer et al. 2004:ca. 145 [ref. 28000]). •Synonym of Poecilia petenensis Günther 1866 -- (Poeser 2002:245 [ref. 26215], Poeser 2003:159 [ref. 26783], Huber 2019:101 [ref. 36941]). Replacement Name. Current status: Synonym of Poecilia petenensis Günther 1866. Poeciliidae: Poeciliinae. Habitat: freshwater.