(Outgroup,((Protohippus_perditus,(Protohippus_supremus,(Calippus_Calippus_placidus,Calippus_Grammohippus_martini))),(Pliohippus_mirabilis,((Hippidion_saldiasi,(Hippidion_devillei,Hippidion_principale)),(Dinohippus_interpolatus,(Onohippidium_galushai,(Dinohippus_leidyanus,(Astrohippus_stocki,(Dinohippus_mexicanus,Equus_simplicidens)))))))));