Opinions from M. F. Skinner and C. W. Hibbard 1972
- 'Amerhippus was reranked as Equus (Amerhippus) and belongs to Equus' according to M. F. Skinner 1972
- 'Dolichohippus was reranked as Equus (Dolichohippus) and belongs to Equus' according to M. F. Skinner 1972
- 'Equus (Asinus) calobatus is recombined as Equus (Hemionus) calobatus' according to M. F. Skinner 1972
- 'Equus (Grevya) belongs to Equus' according to Hilzheimer 1912
- 'Equus (Grevya) is a subjective synonym of Equus (Dolichohippus)' according to M. F. Skinner 1972
- 'Equus (Ludolphozecora) is a subjective synonym of Equus (Dolichohippus)' according to M. F. Skinner 1972
- 'Equus (Ludolphozecora) belongs to Equus' according to Griffini 1913
- 'Equus (Megacephalon) is replaced by Equus (Ludolphozecora)' according to Griffini 1913
- 'Equus (Megacephalon) belongs to Equus' according to Hilzheimer 1912
- 'Equus (Megacephalon) is a subjective synonym of Equus (Dolichohippus)' according to M. F. Skinner 1972
- 'Equus (Megacephalon) is replaced by Equus (Grevya)' according to Hilzheimer 1912
- 'Equus andium belongs to Equus' according to Wagner-Branco 1883
- 'Equus andium is recombined as Equus (Amerhippus) andium' according to M. F. Skinner 1972
- 'Equus conversidens is recombined as Equus (Hemionus) conversidens' according to M. F. Skinner 1972
- 'Equus cumminsii is recombined as Equus (Asinus) cumminsii'
- 'Equus grevyi is recombined as Equus (Dolichohippus) grevyi' according to M. F. Skinner 1972
- 'Equus hemionus is recombined as Hemionus hemionus' according to H. G. Stehlin and E. P. Graziosi 1935
- 'Equus hemionus is recombined as Equus (Hemionus) hemionus' according to M. F. Skinner 1972
- 'Equus minutus is replaced by Nannippus phlegon' according to M. F. Skinner 1972
- 'Equus phlegon is recombined as Nannippus phlegon' according to M. F. Skinner 1972
- 'Equus simplicidens is recombined as Equus (Dolichohippus) simplicidens' according to M. F. Skinner 1972
- 'Equus simplicidens is recombined as Equus (Plesippus) simplicidens' according to Howe 1970
- 'Equus zebra is recombined as Hippotigris zebra' according to Smith 1841
- 'Equus zebra is recombined as Equus (Hippotigris) zebra' according to M. F. Skinner 1972
- 'Hemionus was reranked as Equus (Hemionus) and belongs to Equus' according to M. F. Skinner 1972
- 'Hipparion (Nannippus) belongs to Hipparion' according to W. D. Matthew 1926
- 'Hipparion (Nannippus) was reranked as Nannippus and belongs to Equidae' according to M. F. Skinner 1972
- 'Hipparion gratum is recombined as Griphippus gratus' according to M. F. Skinner 1972
- 'Hippotigris was reranked as Equus (Hippotigris) and belongs to Equus' according to M. F. Skinner 1972
- 'Planisorex belongs to Soricidae'
- 'Plesippus is a subjective synonym of Equus' according to M. F. Skinner 1972
- 'Plesippus was reranked as Equus (Plesippus) and belongs to Equus' according to Howe 1970
- 'Plesippus shoshonensis is a subjective synonym of Equus (Dolichohippus) simplicidens' according to M. F. Skinner 1972
- 'Sorex dixonensis is recombined as Planisorex dixonensis'
- 'Sorex dixonensis belongs to Sorex' according to Hibbard 1956