A beaked bird from the Jurassic of China

Abstract

DISCOVERY of avian remains close to the age of Archaeopteryx in the Liaoning Province of northeastern China provides the earliest evidence for a beaked, edentulous bird. The associated wing skeleton retains the primitive pattern found in Archaeopteryx, including a manus with unfused carpal elements and long digits. Two leg skeletons from the same site also show an Archaeopteryxlevel of morphology, and provide the earliest indisputable evidence for a covering of body contour feathers. These specimens provide evidence for either an undiscovered pre-Archaeopteryx or a rapid, post-Archaeopteryxevolution in birds. As the first Jurassic birds to be described from outside Germany, they show that birds with long fingers terminating in large recurved claws were widely distributed. They are not found in the Early Cretaceous sediments of the same region, where there is a diverse assemblage of more advanced flying birds with smaller fingers and claws. The postcran-ial structure of Archaeopteryx andConfuciusornis seems to be adapted for climbing tree trunks and may have disappeared near the end of the Jurassic.