Abstract: A recently collected specimen of Caudipteryx is described as a new species: C. dongi sp. nov. Compared with the type species of Caudipteryx (C. zoui) the new species has relatively long iliums and smaller sternal plates. Uncinate processes are present as in oviraptorids and most birds. The pubis is antero-ventrally directed as in most saurischian dinosaurs. The fibula contacts the calcaneum distally. Among the pedal digits the third is the longest, the fourth is shorter than the second, and the hallux is short with a reduced claw characteristic of cursorial animals. As in birds the hallux is opposable to the rest of digits, indicating that the ancestor of Caudipteryx might have obtained perching or grasping power, therefore providing further evidence for the arboreal hypothesis of the origin of avian flight. The feather lacks barbules and represents either a more primitive type than in birds or a secondarily reduced one. Although Caudipteryx has several bird characters it is interpreted in this paper as a feathered dinosaur rather than a secondarily flightless bird. Caudipteryx resembles oviraptorids more than dromaeosaurids, yet it represents a lineage distinguishable from all known major maniraptorian clades, therefore we propose to erect a new family: Caudipteridae fam. nov. currently including only Cacidipteryx. The characters of Caudipteryx also indicates that it was a fast running herbivorous animal.