A Primitive Enantiornithine Bird and the Origin of Feathers

A fossil enantiornithine bird, Protopteryx fengningensis gen. et sp. nov., was collected from the Early Cretaceous Yixian Formation of Northern China. It provides fossil evidence of a triosseal canal in early birds. The manus and the alular digit are long, as in Archaeopteryx and Confuciusornis, but are relatively short in other enantiornithines. The alula or bastard wing is attached to an unreduced alular digit. The two central tail feathers...