Paleontologists have unearthed and examined a fossilized leg bone of a phorusrhacid bird that lived 12 million years ago in South America. A model of Paraphysornis at the Natural History Museum Vienna. Image credit: Armin Reindl / CC BY-SA 4.0. Terror birds are members of Phorusrhacidae, a family of large, carnivorous, flightless birds within the order Cariamiformes. These extinct birds had a very large body mass, up to 70 kg, and were between 0.9-2...