Feather a dromaeosaurid found in the Yixian formation (124.6 MYA). Previously, a temporal paradox existed in the evolution of feathers—theropods with highly derived bird-like characteristics occurred at a later time than "Archaeopteryx"—suggesting that the descendants of birds arose before the ancestor. However, the discovery of "Anchiornis huxleyi" in the Late Jurassic Tiaojishan Formation (160 MYA) in western Liaoning in 2009 resolved this paradox. By predating "Archaeopteryx", "Anchiornis" proves the existence of a modernly feathered theropod ancestor, providing insight into the dinosaur-bird transition. The specimen shows distribution of large pennaceous feathers on the forelimbs and tail, implying that pennaceous feathers spread to
Specimens of Archaeopteryx suggest that it had some black colouration which included the coverts (or possibly the secondary remiges). Carney pointed out that this is consistent with what we know of modern flight characteristics, in that black melanosomes have structural properties that strengthen feathers for flight. The preservation of the fossil feather is unusual. In contrast to the feather imprints found on the full skeletons of "Archaeopteryx", the isolated feather is preserved as a dark film, which could be composed either of organic matter (as in most fossil feathers) or as inorganic minerals. Though it is theoretically possible to determine which it is,