Researchers in Germany have unearthed a new species of flying dinosaur that flapped its wings like a raven and could hold vital clues as to how modern-day birds evolved from their reptilian ancestors. For more than a century and a half since its discovery in 1861, Archaeopteryx -- a small feathered dinosaur around the size of a crow that lived in marshland around 150 million years ago -- was widely considered to be the oldest flying bird.