Opinions from B. H. Slaughter 1966
- 'Auchenia huerfanensis is recombined as Camelops huerfanensis'
- 'Bison alleni belongs to Bison'
- 'Bison chaneyi belongs to Bison'
- 'Camelops huerfanensis dallasi belongs to Camelops huerfanensis' according to Lull 1921
- 'Camelops huerfanensis dallasi belongs to Camelops huerfanensis'
- 'Crocuta inexpectata is recombined as Felis inexpectata'
- 'Elasmognathus bairdii is recombined as Tapirus bairdii'
- 'Elephas americanus [misspelled as Mammut americanus] belongs to Mammut'
- 'Equus conversidens belongs to Equus'
- 'Equus lambei belongs to Equus'
- 'Equus midlandensis belongs to Equus'
- 'Equus quinni belongs to Equus'
- 'Felis rufa is recombined as Lynx rufus'
- 'Hippopotamus terrestris is recombined as Tapirus terrestris'
- 'Holomeniscus macrocephalus is recombined as Tanupolama macrocephala'
- 'Lama hollomani is recombined as Tanupolama hollomani'
- 'Lama stevensi is a subjective synonym of Tanupolama macrocephala'
- 'Lynx compressus belongs to Lynx' according to Brown 1908
- 'Lynx compressus is a subjective synonym of Lynx rufus'
- 'Megalonyx brachycephalus belongs to Megalonyx'
- 'Odocoileus virginianus aplodon belongs to Odocoileus virginianus' according to Slaughter et al. 1962
- 'Odocoileus virginianus aplodon belongs to Odocoileus virginianus'
- 'Platygonus compressus belongs to Platygonus'
- 'Tanupolama blancoensis belongs to Tanupolama'
- 'Tanupolama mirifica belongs to Tanupolama'
- 'Tapirus copei belongs to Tapirus'
- 'Tapirus haysii is a subjective synonym of Tapirus copei'
- 'Tapirus haysii californicus is recombined as Tapirus californicus'
- 'Tapirus merriami belongs to Tapirus'
- 'Tapirus veroensis belongs to Tapirus'
- 'Tetrameryx knoxensis belongs to Tetrameryx'
- 'Tetrameryx shuleri belongs to Tetrameryx'