FURCULAE OF NON-AVIAN THEROPODS AND BASAL BIRDS

摘要

The morphologies and structures of the furculae in non-avian theropods and basal birds are reviewed. The furculae of non-avian theropods are homologous with the avian furculae. The presence of a furcula in different non-avian theropods (coelophysoids, allosaurids, carcharodontosaurids, compsognathids, tyrannosauroids, oviraptorids, therizinosauroids, troodontids, and dromaeosaurids) indicates that the furcula is not a diagnostic feature for birds, but may be a synapomorphy for Theropoda. The presence of hypocleideum represents a more derived feature through the development of furcula, and the hypocleideum arose independently at least five times in different maniraptoran clades. Moreover, the narrow interclavicular angle of the furcula in maniraptorans (including birds) is evidently more derived than the wide angle in non-maniraptoran theropods.