Protoavis are well preserved, and they are astonishingly non-avian. The distal carpals, while long, are in no way similar to those observed in the urvogel or other archaic birds. There is no semilunate element, and the structure of the radiale and ulnare would have limited the flexibility of the wrist joint. The manus is not tridactyl, and metacarpal V is present. In even the most basal avialian, "Archaeopteryx", there is no vestige of the fifth metacarpal and its presence in "Protoavis" seems incongruous with the claim that it is a bird, let alone one more derived than "Archaeopteryx". Chatterjee claims that
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