Opinions from B. J. Mader 1989
- 'Allops is a subjective synonym of Menops'
- 'Allops crassicornis is recombined as Menops crassicornis'
- 'Allops serotinus is recombined as Menops serotinus'
- 'Allops walcotti is recombined as Menops walcotti'
- 'Anisacodon montanus is a nomen dubium'
- 'Brontops belongs to Brontotheridae'
- 'Brontops dispar belongs to Brontops'
- 'Brontops robustus belongs to Brontops'
- 'Brontops validus is a subjective synonym of Brontops dispar'
- 'Brontotherium is a nomen dubium'
- 'Brontotherium gigas is a nomen dubium'
- 'Brontotherium hatcheri is recombined as Megacerops hatcheri'
- 'Brontotherium ingens is a nomen dubium'
- 'Brontotherium leidyi is a nomen dubium'
- 'Diconodon is a nomen dubium'
- 'Diplacodon emarginatus is recombined as Protitanotherium emarginatum'
- 'Diploceras is a subjective synonym of Eotitanotherium'
- 'Diploceras osborni is recombined as Eotitanotherium osborni'
- 'Diploclonus is a subjective synonym of Brontops'
- 'Diploclonus amplus is recombined as Brontops amplus'
- 'Eometarhinus is a subjective synonym of Palaeosyops'
- 'Eotitanops belongs to Brontotheridae'
- 'Eotitanops is a subjective synonym of Palaeosyops' according to Wallace 1980
- 'Eotitanops belongs to Brontotheridae' according to Osborn 1907
- 'Eotitanops gregoryi is a subjective synonym of Eotitanops borealis'
- 'Eotitanops minimus is a subjective synonym of Eotitanops gregoryi'
- 'Eotitanotherium belongs to Brontotheridae'
- 'Eotitanotherium is a subjective synonym of Diplacodon' according to Lucas 1983
- 'Leurocephalus is a subjective synonym of Telmatherium'
- 'Leurocephalus cultridens is recombined as Telmatherium cultridens'
- 'Limnohyops is a subjective synonym of Palaeosyops'
- 'Limnohyops is a subjective synonym of Palaeosyops' according to Earle 1895
- 'Limnohyops priscus is recombined as Palaeosyops priscus'
- 'Limnohyus is a subjective synonym of Palaeosyops'
- 'Limnohyus laevidens belongs to Limnohyus'
- 'Limnohyus laticeps is recombined as Palaeosyops laticeps' according to Matthew 1899
- 'Limnohyus laticeps is recombined as Palaeosyops laticeps' according to Matthew 1897
- 'Limnohyus laticeps is recombined as Palaeosyops laticeps' according to Earle 1895
- 'Limnohyus laticeps is recombined as Palaeosyops laticeps'
- 'Manteoceras is a subjective synonym of Telmatherium'
- 'Manteoceras foris is recombined as Telmatherium foris'
- 'Manteoceras foris belongs to Manteoceras' according to Cook 1926
- 'Manteoceras pratensis is recombined as Telmatherium pratensis'
- 'Manteoceras pratensis belongs to Manteoceras' according to Cook 1926
- 'Manteoceras uintensis is a subjective synonym of Metatelmatherium ultimum'
- 'Manteoceras washakiensis is recombined as Telmatherium washakiensis'
- 'Megaceratops is a subjective synonym of Megacerops'
- 'Megaceratops acer is recombined as Megacerops acer'
- 'Megaceratops helocerus is recombined as Menops heloceras'
- 'Megacerops belongs to Brontotheridae'
- 'Megacerops assiniboiensis is a nomen dubium'
- 'Megacerops bicornutus is recombined as Brontops bicornutus'
- 'Megacerops marshi is recombined as Menops marshi'
- 'Megacerops riggsi is a nomen dubium'
- 'Megacerops tyleri is recombined as Brontops tyleri'
- 'Menodus bakeri is recombined as Menops bakeri'
- 'Menodus dolichoceras is a nomen dubium'
- 'Menodus peltoceras is a subjective synonym of Megacerops curtus'
- 'Menodus selwynianus is recombined as Brontops selwynianus'
- 'Menodus tichoceras is a nomen dubium'
- 'Menops belongs to Brontotheridae'
- 'Menops varians belongs to Menops'
- 'Palaeosyops borealis is recombined as Eotitanops borealis'
- 'Palaeosyops borealis is recombined as Eotitanops borealis' according to West 1973
- 'Palaeosyops borealis is recombined as Eotitanops borealis' according to Robinson 1966
- 'Palaeosyops hyognathus is recombined as Dolichorhinus hyognathus'
- 'Palaeosyops manteoceras is a nomen nudum'
- 'Palaeosyops megarhinus is recombined as Mesatirhinus megarhinus'
- 'Palaeosyops vallidens is recombined as Telmatherium vallidens'
- 'Menodus is a nomen dubium'
- 'Palaeotherium (Menodus) was reranked as Menodus and belongs to ' according to Cope 1886
- 'Palaeotherium giganteum is a nomen dubium'
- 'Palaeotherium proutii is a nomen dubium'
- 'Protitanotherium belongs to Brontotheridae'
- 'Protitanotherium is a subjective synonym of Diplacodon' according to Lucas 1983
- 'Sthenodectes australis belongs to Sthenodectes' according to J. Wilson 1977
- 'Symborodon is a nomen dubium'
- 'Symborodon altirostris is a subjective synonym of Megacerops acer'
- 'Symborodon bucco is a nomen dubium'
- 'Symborodon copei is a nomen dubium'
- 'Symborodon hypoceras is a nomen dubium'
- 'Symborodon torvus is a nomen dubium'
- 'Symborodon trigonoceras is recombined as Menops trigonoceras'
- 'Teleodus uintensis is recombined as Duchesneodus uintensis'
- 'Telmatotherium is a subjective synonym of Telmatherium'
- 'Telmatherium incisivum is recombined as Sthenodectes incisivum'
- 'Telmatherium ultimum is recombined as Metatelmatherium ultimum'
- 'Telmatotherium cornutum is recombined as Dolichorhinus cornutum'
- 'Telmatotherium diploconum is recombined as Rhadinorhinus diploconum'
- 'Titanops is a subjective synonym of Megacerops'
- 'Titanops curtus is recombined as Megacerops curtus'
- 'Titanops elatus is recombined as Megacerops elatus'
- 'Titanops medius is a nomen dubium'
- 'Titanotheriidae is a subjective synonym of Brontotheridae'
- 'Titanotherium is a nomen dubium'