gracilis, Xiphophorus Heckel [J. J.] 1848:300, Pl. 9 (figs. 3-4) [Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften. Mathematisch-Naturwissenschaftliche Classe v. 1 (pt 1-5) [1848]; ref. 2069] Orizaba, Mexico. Syntypes: (13) NMW 59600 (3), 76512 (6), 76514 (2, dry), 81118 (4). •Valid as Poeciliopsis gracilis (Heckel 1848) -- (Rosen & Bailey 1963:136 [ref. 7067], Lee et al. 1980:552 [ref. 22416], Villa 1982:135 [ref. 36708], Page & Burr 1991:240 [ref. 18983], Espinosa Pérez et al. 1993:51 [ref. 22290], Fuller et al. 1999:314 [ref. 25838], Moyle 2002:324 [ref. 26449], Lucinda in Reis et al. 2003:570 [ref. 27061], Nelson et al. 2004:105 [ref. 27807], Lucinda & Reis 2005:43 [ref. 29205], Miller 2006:243 [ref. 28615] restricted to e. Mexico, Scharpf 2007:21 [ref. 30398], Bussing 2008:834 [ref. 29806], Minckley & Marsh 2009:257 [ref. 31114], Page & Burr 2011:452 [ref. 31215], Page et al. 2013:110 [ref. 32708], Meyer 2015:287 [ref. 34698], Huber 2019:127 [ref. 36941], López-Segovia et al. 2020:111 [ref. 38151], Ward et al. 2022:7 [ref. 39030], Angulo et al. 2023:62 [ref. 40676]). Current status: Valid as Poeciliopsis gracilis (Heckel 1848). Poeciliidae: Poeciliinae. Distribution: Southern North America, Central America: Atlantic slope of Mexico south to Honduras: El Salvador, Guatemala, Honduras, Mexico. Introduced in California (U.S.A.) and Venezuela. Habitat: freshwater.