Terror birds
A recently discovered species is Kelenken guillermoi from the middle of the Miocene some 15 million years ago. It was found in Patagonia in 2006. It had the largest bird skull yet found. The fossil has been described as having a  nearly intact skull. The beak is roughly  long and curves in a hook shape that resembles an eagle's beak. Most species described as phorusrhacid were smaller,  tall, but the new fossil belongs to a bird that probably stood about  tall. The large terror birds were nimble and quick runners able to reach speeds of .