Opinions from R. C. Hulbert 1988

  • 'Calippus (Calippus) belongs to Calippus'
  • 'Calippus (Calippus) elachistus belongs to Calippus (Calippus)'
  • 'Calippus (Grammohippus) belongs to Calippus'
  • 'Calippus (Grammohippus) cerasinus belongs to Calippus (Grammohippus)'
  • 'Calippus (Grammohippus) maccartyi belongs to Calippus (Grammohippus)'
  • 'Calippus anatinus is a subjective synonym of Calippus (Calippus) regulus'
  • 'Calippus martini is recombined as Calippus (Grammohippus) martini'
  • 'Calippus optimus is a subjective synonym of Calippus (Calippus) placidus'
  • 'Calippus regulus is recombined as Calippus (Calippus) regulus'
  • 'Dinohippus subvenus is a subjective synonym of Pliohippus pernix'
  • 'Eoequus is a subjective synonym of Protohippus'
  • 'Eoequus wilsoni is a subjective synonym of Protohippus perditus'
  • 'Equini belongs to Equidae'
  • 'Equus (Protohippus) was reranked as Protohippus and belongs to Protohippina'
  • 'Equus (Protohippus) perditus is recombined as Protohippus perditus'
  • 'Equus (Protohippus) perditus is recombined as Protohippus perditus' according to Evander 1978
  • 'Equus laparensis is a subjective synonym of Calippus (Grammohippus) martini'
  • 'Hippotigris clarendonensis is a subjective synonym of Protohippus supremus'
  • 'Hippotigris parastylus is a subjective synonym of Protohippus supremus'
  • 'Hippotigris sellardsi is a subjective synonym of Protohippus supremus'
  • 'Merychippus francisi is a subjective synonym of Calippus (Calippus) placidus'
  • 'Pliohippus circulus is recombined as Calippus (Grammohippus) circulus'
  • 'Pliohippus hondurensis is recombined as Calippus (Grammohippus) hondurensis'
  • 'Protohippini was reranked as the subtribe Protohippina and belongs to Equini'
  • 'Protohippus (Calippus) was reranked as Calippus and belongs to Protohippina'
  • 'Protohippus gidleyi belongs to Protohippus'
  • 'Protohippus placidus is recombined as Calippus (Calippus) placidus'
  • 'Protohippus placidus is recombined as Calippus placidus' according to Webb 1969
  • 'Protohippus profectus is a subjective synonym of Protohippus perditus'
  • 'Protohippus proplacidus is recombined as Calippus (Calippus) proplacidus'
  • 'Protohippus simus is a subjective synonym of Protohippus supremus'
  • 'Protohippus supremus belongs to Protohippus'
  • 'Protohippus vetus belongs to Protohippus'