Hipparion coloradense- Hippotherium relictum
- Merychippus brevidontus
- Merychippus californicus
- Merychippus gunteri
- Merychippus insignis
- Merychippus intermontanus
- Merychippus isonesus
- Merychippus mirabilis
- Merychippus missouriensis
- Merychippus republicanus
- Merychippus sejunctus
- Merychippus sphenodus
- Merychippus sumani
- Merychippus westoni
- Protohippus labrosus
- Stylonus seversus