alvarezi, Xiphophorus helleri Rosen [D. E.] 1960:126, Figs. 19, 20, 23, 32 [Bulletin of the Florida State Museum, Biological Sciences v. 5 (no. 4); ref. 11945] Río Santo Domingo, a tributary of Río Jatate, Río Usumacinta system, Chiapas, Mexico. Holotype: UMMZ 177304. Paratypes: UMMZ 177305 (1, allotype). Other material: BMNH 1950.12.12.1-2 (2), UMMZ 160727 (2), J. Alvares coll. (16). •Synonym of Xiphophorus helleri Heckel 1848, but a valid subspecies -- (Rosen & Bailey 1963:66 [ref. 7067]). •Valid as Xiphophorus alvarezi Rosen 1960 -- (Rosen 1979:357 [ref. 22796], Espinosa Pérez et al. 1993:54 [ref. 22290], Rodriguez 1997:674 [ref. 23266], Meyer & Schartl 2002:59 [ref. 26066], Lucinda in Reis et al. 2003:573 [ref. 27061], Meyer & Schartl 2003:62 [ref. 27477], Kallman et al. 2004:9 [ref. 27790], Nelson et al. 2004:105 [ref. 27807], Lucinda & Reis 2005:44 [ref. 29205], Miller 2006:254 [ref. 28615], Scharpf 2007:17 [ref. 30398], Page et al. 2013:111 [ref. 32708], Meyer 2015:368 [ref. 34698], Huber 2019:143 [ref. 36941], Barrientos et al. 2023:274 [ref. 41235], Page et al. 2023:148 [ref. 40505], Quintana 2024:8 [ref. 41186]). Current status: Valid as Xiphophorus alvarezi Rosen 1960. Poeciliidae: Poeciliinae. Distribution: Southern North America, Central America: Atlantic slope (Guatemala and Mexico). Habitat: freshwater.