A gliding, four-winged dinosaur’s feathers:
Dinosaurs, such as Anchiornis, had shaggy, primitive feathers prior to the evolution of highly adapted feathers in modern birds.
Structures in dinosaur fossils are feathers, not collagen:
A likely final blow against the argument that filaments around the bones are collagen fibers from the skin. They are feathers, based on overwhelming evidence.
Psittacosaurus tail bristles resemble those of modern birds:
External and internal structural similarities suggest shared ancestry of basic developmental processes in feathers deep into archosaur evolution. Bristles possibly functioned in sexual display.