clarkii, Catostomus Baird [S. F.] & Girard [C. F.] 1854:27 [Proceedings of the Academy of Natural Sciences of Philadelphia v. 7; ref. 168] Sonoito Creek, tributary to Rio Santa Cruz, about 10-15 miles north-northeast of Nogales, Santa Cruz County, Arizona, U.S.A. Syntypes: MCZ 2261 [ex USNM 167] (1); MNHN 0000-0425 [ex USNM 167] (1); USNM 166 (orig. 4, now 3), 167 (orig. 4, now 2, plus 2 pharyngeal arches). Type catalog: Gilbert 1998:176 [ref. 23395] with locality information. •Valid as Catostomus clarkii Baird & Girard 1854 [often as clarki] -- (Smith 1966:73 [ref. 21398], Lee et al. 1980:373 [ref. 22416], Crabtree & Buth 1987:843 [ref. 6770], Page & Burr 1991:177 [ref. 18983], Espinosa Pérez et al. 1993:22 [ref. 22290], Sigler & Sigler 1996:129 [ref. 25943], Gilbert 1998:176 [ref. 23395], Nelson et al. 2004:78 [ref. 27807], Miller 2006:146 [ref. 28615], Scharpf 2006:5 [ref. 30386], Page & Burr 2011:320 [ref. 31215], Page et al. 2013:79 [ref. 32708], Smith et al. 2013:3,15 [ref. 32735], Bangs et al. 2018:4 [ref. 37913]). •Valid as Pantosteus clarkii (Baird & Girard 1854) -- (Minckley & Marsh 2009:201 [ref. 31114] as clarki, Unmack et al. 2014:7 [ref. 36004], Bagley et al. 2018:25 [ref. 36001], Page et al. 2023:65 [ref. 40505], Fricke et al. 2024:160 [ref. 41622]). Current status: Valid as Pantosteus clarkii (Baird & Girard 1854). Catostomidae: Catostominae. Distribution: North America: Río Colorado system, southwestern U.S.A. and northern Mexico. Habitat: freshwater.