* "T. albertensis" (C. M. Sternberg, 1949)* "T. alticornis" (Marsh, 1887 "Bison")* "T. brevicornus" (Hatcher, 1905) (="T. prorsus")* "T. calicornis" (Marsh, 1898) (="T. horridus")* "T. elatus" (Marsh, 1891) (="T. horridus")* "T. eurycephalus" (Schlaikjer, 1935)* "T. flabellatus" (Marsh, 1889) (="T. horridus")* "T. galeus" (Marsh, 1889)* "T. hatcheri" (Lull, 1907) (contentious; see "Nedoceratops" below)* "T. ingens" (Lull, 1915)* "T. maximus" (Brown, 1933)* "T. mortuarius" (Cope, 1874) ("nomen dubium"; originally "Polyonax mortuarius")* "T. obtusus" (Marsh, 1898) (="T. horridus")* "T. serratus" (Marsh, 1890) (="T. horridus")* "T. sulcatus" (Marsh, 1890)* "T. sylvestris" (Cope, 1872) ("nomen dubium"; originally "Agathaumas sylvestris")====="Nedoceratops"=====The paper that described "Nedoceratops" was originally part of O. C. Marsh's magnum opus, his Ceratopsidae monograph.
To idejo je Lehman združil s starimi Lull-Sternbergovimi skupinami in predlagal, da skupino "T. horridus"-"T. prorsus"-"T. brevicornus" predstavljajo samice, "T.calicornis"-"T.elatus" samci, "T. obtusus"-"T. hatcheri" pa nenavadno stari ali bolni samci.