Polacanthus had more flexible armor

similar to today's African savannah

which lived in the late Cretaceous period

approximately 75 to 70 million years ago

Medusaceratops possessed a horny beak at the front of its skull and a prominent bony ruff at the rear

Kelenken Variant:Unprimed Polacanthus had more flexible armorKelenken (K. guillermoi `Terror Bird) is a genus of phorusrhacidae, an extinct group of large predatory birds that lived in the Middle Miocene to Neogene Epoch, about 15 million years ago, in what is now Argentina. Phororracids were large flightless birds with long hindlimbs, narrow pelvises, proportionately small wingspans, and huge skulls with a hooked beak and are thought to have been dominant land predators or scavengers in the Cenozoic. Kelenken