Archaeopteryx was discovered in the 1860s and provided the first hint that birds and dinosaurs may be related. (Image credit: meen_na/Getty Images) In the 1970s, paleontologist John Ostrom revived the theory that modern birds are evolved from theropod dinosaurs, a group that includes Tyrannosaurus rex . But a key piece of evidence was missing: feathered fossils. Then, a chance discovery in China upended our understanding of bird evolution. In this excerpt from " The Story of Birds: An Evolutionary History of the Dinosaurs That Live Among Us " (Mariner Books, 2026), author and paleontologist Steve Brusatte looks at the monumental shift in dinosaur research after the first feathered dinosaur was discovered. For well over a century, since its discovery in the Bavarian lithographic mines in 1861, the fossil bird Archaeopteryx was the oldest and most primitive creature known to have feathers. Then, in the autumn of 1996, this understanding was upended.…