THE ENVIRONMENTAL BACKGROUND, RESEARCH STATUS AND PROSPECTS ON FLIGHT OF EARLY CRETACEOUS CONFUCIUSORNITHID BIRDS IN NORTH CHINA AND ITS ADJACENT REGIONS

We investigated numerous related literatures of confuciusomithid birds and summarized in terms of environmental background, research status (including morphology, evolutionary characteristics, and flight capability) and prospects. It is expected to generate a new idea and perspective for the study of Early Cretaceous paleontology and paleoenvironmentology. Confuciusomithidae is an important group of fossil birds, which has developed tremendously in north China and other east Asian regions during Early Cretaceous. They are studied deeper than many other birds, because of the significance of evolutionary status and many exquisite specimens unmatched by other birds in the same period. And confuciusomithid birds are also the focus of paleornithology and paleoenvironment in the reason of their coevolutionary relation. By now, the flight capability of Confuciusomithidae has not been proved, though it was one group of fossil birds with large feathers. There are also no extant birds with aerodynamic feathers on their hindlimbs. Therefore, the flight capability has not been knowed by accurate comparsion at present; the previous conclusions came from morphological analogy and functional speculation; and the research on the origin and evolution of bird flight is also limited by that. Fortunately, hindlimb feathers with aerodynamic characteristics have been found on the Deinonychus and other early birds in the past two decades, which strongly supports hindlimbs are important in the origin of birds flight. And the hindlimbs of birds play an irreplaceable role in aerial and ground locomotion. As a consequence, the hindlimbs aerodynamic performance of confuciusomithid birds will be a breakthrough in the future research. In addation, the proceeding of the digital revolution pleases us immensely that the advancements of computer technologies make the quantitative studies of birds flight more accessible. In the long run, the research of the life habits of Confuciusornithidae can provide valuable data for the coevolution of paleomithology and paleoenvironment in Early Cretaceous.