Fig. (2) UV photograph of the manual claws of a Microraptor showing the keratinous sheath covering unguals III and IV [14]. These highly adapted and strongly curved and laterally compressed manual claws are typical of trunk-climbing early birds such as Archaeopteryx, as well as claws of woodpeckers and other scansorial birds, as well as mammals such as squirrels, etc., and provide conclusive evidence of trunk-climbing habits in this early avian “tetrapteryx” offshoot. (Courtesy D. Burnham).