WHEN IS A DINOSAUR NOT A DINOSAUR? The rulers of prehistoric Earth are having an identity crisis, says Colin Barras.

The article discusses the history of paleontological research into the evolution of early dinosaurs including the history of natural scientist Harry Seeley's classification of saurischians and ornithischians as different clades and his denigration of dinosaurs as a taxonomic term as well as the subsequent discovery of a bipedal, omnivorous common ancestor species which ultimately developed into sauropodomorphs, theropods, and ornithischians.