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 on the main slab. Both arms are preserved close to their natural articulation with the shoulder girdle, though displaced. The ulna is more robust and curved than the slender radius. A confusing jumble of metacarpals has led some researchers to conclude the beginning of fusion between carpals and metacarpals; this has been rejected by later researchers. Most manual bones of the right wing are missing, and the left wing preserves two metacarpals, the semilunate carpal, and two long, slender phalanges with large, strongly-curved claws. The missing third finger led Owen to conclude a two-fingered hand for "Archaeopteryx" in his original