Prehistoric Giants on Instagram: "Megacerops | Life On Our Planet Megacerops is an extinct genus of the prehistoric odd-toed ungulate (hoofed mammal) family Brontotheriidae, an extinct group of rhinoceros-like browsers related to horses. It was endemic to North America during the Late Eocene epoch (38–33.9 mya), existing for approximately 4.1 million years. Dunkleosteus was covered in dermal bone forming armor plates across its skull and front half of its trunk. This armor is often described as