page_title: Anchiornis
section_title: Description
hierarchical_section_title: Anchiornis / Description
context_page_description: Anchiornis is a genus of small, four-winged paravian dinosaur. The genus Anchiornis contains only the type species Anchiornis huxleyi, named for its similarity to modern birds. Anchiornis fossils have been only found in the Tiaojishan Formation of Liaoning, China, in rocks dated to the Late Jurassic, about 160 million years ago. Anchiornis is known from hundreds of specimens, and given the exquisite preservation of some of these fossils, it became the first Mesozoic dinosaur species for which almost the entire life appearance could be determined, and an important source of information on the early evolution of birds. Anchiornis huxleyi translates to "Huxley's near-bird" in Greek.
context_section_description: Anchiornis huxleyi was a small, bipedal theropod dinosaur with a triangular skull bearing several details in common with dromaeosaurids, troodontids, and primitive avialans. Like other early paravians, Anchiornis was small, about the size of a crow. It had long, wing-bearing arms, long legs, and a long tail. Like all paravians, it was covered in feathers, though it also had scales on certain parts of the body. The wings, legs, and tail supported long but relatively narrow vaned feathers. Two types of simpler, downy (plumaceous) feathers covered the rest of the body, as in Sinornithosaurus: down feathers made up of filaments attached at their bases, and more complex down feathers with barbs attached along a central quill. Long, simple feathers covered almost the entire head and neck, torso, upper legs, and the first half of the tail. The rest of the tail bore pennaceous tail feathers (rectrices). Long feathers on the head (crown) may have formed a crest. While the first specimen of Anchiornis preserved only faint traces of feathers around the preserved portion of the body, many more well-preserved fossils have since been found. Studies of Anchiornis specimens using laser fluorescence have revealed not only more details of the feathers, but also of the skin and muscle tissue. Taken together, this evidence has given scientists a nearly complete picture of Anchiornis anatomy. Additional studies indicate that Anchiornis had body plumage that consisted of short quills with long and independent, flexible barbs. These barbs stuck out from the quills at low angles on two opposing blades. This also gave each feather an overall forked shape and resulted in the theropod possessing a softer textured and "shaggier" appearing plumage than is seen in modern birds. 'Shaggy' contour feathers probably influenced thermoregulatory and water repellence abilities, and, in combination with open-vaned wing feathers, would have decreased aerodynamic efficiency.
  Its size was originally estimated at 34 centimetres (13 in; 1.12 ft) and 0.11 kilograms (0.24 lb), but some specimens show that is could in fact have grown somewhat larger, up to 40 centimetres (16 in; 1.3 ft) and 0.25 kilograms (0.55 lb). Anchiornis had a wing span of up to 50 centimetres (20 in; 1.6 ft).
caption: Size compared with a human