Bird display both clearly traditional reptilian characteristics: teeth, clawed fingers, and a long, lizard-like tail, as well as wings with flight feathers similar to those of modern birds. It is not considered a direct ancestor of birds, though it is possibly closely related to the true ancestor. The earliest known avialan fossils come from the Tiaojishan Formation of China, which has been dated to the late Jurassic period (Oxfordian stage), about 160 million years ago. The avialan species from this time period include "Anchiornis huxleyi", "Xiaotingia zhengi", and "Aurornis xui". The well-known early avialan, "Archaeopteryx", dates from slightly later Jurassic rocks
Feathers: The Evolution of a Natural Miracle "Archaeopteryx" fossil specimen and the resulting debate between English paleontologist Richard Owen, an opponent to evolution by natural selection, and Thomas Henry Huxley, an advocate for evolution. Hanson himself visits the Wyoming Dinosaur Center, a small museum in Thermopolis, Wyoming, which had acquired an "Archaeopteryx" specimen. Hanson interviews Richard Prum, the Coe Professor of Ornithology at Yale University, who proposed a developmental theory of feather evolution, which focuses "on how feathers grow and not worrying about what they're used for." Hanson also interviews Alan Feduccia, a professor at the University of North Carolina, who disagrees with the scientific consensus that