A genus of fossil birds in the extinct order Archaeopterygiformes, characterized by flight feathers like those of modern birds. Archaeopteryx is generally accepted as the oldest known fossil bird. It represents a unique snapshot of evolution; most of its skeletal characters are shared with small carnivorous dinosaurs, yet it has fully feathered modern wings. Archaeopteryx is effectively a flying dinosaur—an ancient bird about the size of a modern magpie.