Outgroup
Protohippus_perditus
Protohippus_supremus
Calippus_Grammohippus_martini
Calippus_Calippus_placidus
Pliohippus_mirabilis
Hippidion_saldiasi
Hippidion_principale
Hippidion_devillei
Dinohippus_interpolatus
Onohippidium_galushai
Dinohippus_leidyanus
Astrohippus_stocki
Equus_simplicidens
Dinohippus_mexicanus