Specimens of Archaeopteryx The end of the feather has an obtuse angle of 110°, while the barbs branch off from the rachis at an angle of around 25°. The barbs branch noticeably into barbules, as in the feathers of modern birds. The base of the feather consists of plumulaceous barbs which are unconnected to one another and result in a down-like appearance. This tuft of down led Griffiths to conclude that "Archaeopteryx" might have been endothermic in that it implies the use of thermal insulation. The feather is clearly asymmetrical, which has been interpreted by many scientists to be a clear indication of
Specimens of Archaeopteryx its aerodynamic function as a flight feather. As the feather bears little resemblance to the retrices of the other full "Archaeopteryx" skeletons, it is generally thought to be a wing feather: Griffiths and others have concluded it was a remex, while Carney in 2012 interpreted it to be a covert feather. The feather has a relatively low degree of asymmetry, which Speakman and Thompson in 1994 concluded to indicate it as a secondary remex. If this is the case, then it would have originated from an animal smaller than even the Eichstätt specimen, which is the smallest "Archaeopteryx" specimen known