Platygobio gulonellus Cope, 1865:85 ("Platte R., near Fort Riley" [Fort Riley is on Kansas R., not Platte R.; Cope's specimens probably are from Platte drainage, on basis of known distributions of other species reported]).
Ceratichthys physignathus Cope and Yarrow, 1875:651 (original description; Arkansas R., Pueblo, Colo.).
Platygobio communis, Gill, 1876:408 (characters; Platte Valley; Green River, Utah [the latter probably erroneous]).
Couesius physignathus, Jordan and Gilbert, 1882:219 (characters; synonymy; Arkansas R., Pueblo, Colo.); Jordan, 1885:29 (records).
Platygobio gracilis, Jordan and Gilbert, 1882:219 (in part; characters; synonymy); Cragin, 1885:109 (Garden City, Kans.); Gilbert, 1885:98 (Garden City, Kans.); Jordan, 1885:29 (records); Evermann and Cox, 1896:412 (in part; habitat; synonymy); Jordan and Evermann, 1896:326 (in part; characters; synonymy); Ortenburger and Hubbs, 1927:125 (Canadian R., Norman, Okla.); Hubbs, 1927:75 (parasites; teratology; records from New Mexico); Hubbs and Ortenburger, 1929a:28 (S. Canadian R., Durham, Okla.); Jordan, 1929:76 (in part; characters); Jordan, Evermann and Clark, 1930:136 (in part; synonymy).
Platygobio physignathus, Jordan and Evermann, 1896:325 (characters; synonymy; records from upper Arkansas R.); Ellis, 1914:62 (characters; synonymy; records from Colorado); Cockerell, 1927:123 (distribution in Colorado); Jordan, Evermann and Clark, 1930:136 (synonymy; records from upper Arkansas R.).
Platygobio gracilis communis, Simon, 1946:71 (in part; characters; food; habitat; spawning).
Platygobio gracilis gulonellus, Simon, 1946:72 (characters; records from Wyoming; Arkansas R.).
Platygobio gracilis: communis × gulonellus, Simon, 1946:92 (North Platte R., Neb.-Wyo. line).
Platygobio gracilis physignathus, Moore, 1950:87 (habitat; sense organs).