Plateosaurus ( meaning ` flat lizard ' ) is a genus of plateosaurid prosauropod dinosaur that lived during the Norian and Rhaetian stages of the Late Triassic Period , around 216 to 199 million years ago in what is now Europe . Plateosaurus ( meaning ` broadway lizard ' , often mistranslated as ` flat lizard ' or ` broad lizard ' ) is a genus of plateosaurid dinosaur that lived during the Late Triassic period , around 216 to 199 million years ago , in what is now Central and Northern Europe . Plateosaurus is a basal sauropodomorph dinosaur , a so-called prosauropod .