pachycephalus, Cyprinodon Minckley [W. L.] & Minckley [C. O.] 1986:184, Figs. 1-2 [Copeia 1986 (no. 1); ref. 8066] Baños de San Diego, east of Chihuahua, Mexico, 28°35.5'N, 105°32.5'W, elevation about 1140 meters. Holotype: UMMZ 213401. Paratypes: ASU 6415 (100), UMMZ 213402 (25). Additional material: UMMZ 203016, 207704, 207705, and other UMMZ uncat. lots. •Valid as Cyprinodon pachycephalus Minckley & Minckley 1986 -- (Espinosa Pérez et al. 1993:34 [ref. 22290], Echelle & Echelle 1998:855 [ref. 23614], Lazara 2001:91 [ref. 25711], Lozano-Vilano 2002:20 [ref. 27832], Nelson et al. 2004:109 [ref. 27807], Miller 2006:308 [ref. 28615], Scharpf 2007:33 [ref. 30398], De la Maza-Benignos & Vela-Valladares in Maza-Benignos 2009:185 [ref. 30589], Page et al. 2013:107 [ref. 32708], Lozano-Vilano & De la Maza-Benignos 2016:26 [ref. 35401], Esmaeili et al. 2018:15 [ref. 36738], Page et al. 2023:142 [ref. 40505]). Current status: Valid as Cyprinodon pachycephalus Minckley & Minckley 1986. Cyprinodontidae: Cyprinodontinae. Distribution: Southern North America: San Diego de Alcalá (Atlantic Slope of Mexico). Habitat: freshwater.