Diversification in an Early Cretaceous avian genus: evidence from a new species of Confuciusornis from China

A new species of Confuciusornis, the oldest known beaked bird, is erected based on a nearly complete fossil from the Early Cretaceous Yixian Formation of western Liaoning, northeast China. C. feducciai is the largest and shows the highest ratio of the forelimb to the hindlimb among all known species of Confuciusornis. The skeletal qualitative autapomorphies, including a V-shaped furcula, a rectangular deltopectoral crest, the absence of an oval foramen at the proximal end of the humerus, the very slender alular digit, a relatively much longer ischium which is two-thirds the length of the pubis, and the morphology of sternum, strongly suggest the new specimen is a valid distinctive taxon. Detailed comparison with other described species provides sound evidence for diversification in the Early Cretaceous avian genus Confuciusornis. Anatomical features suggest an arboreal habit of the new bird.