Rare Ancient Bird Fossil with Preserved Feathers
Protopteryx fengningensis
from Hebei Province, China

The Enantiornithine birds at one time were the dominant group of birds during the Creatceous, only to go the way of the dinosaurs by the end of the perioid. Their name is derived in the meaning "opposite birds" due to a reverse articular arrangement between the scapula and the coracoid from the typical birds of today. Protopteryx is the most primitive member of this subfamily, and was described just four years ago from two wonderfully-preserved specimens This bird sported three different types of feathers: downy feathers for the head and body, typical flight feathers, and strange central tail feathers. The long tail feathers appear to have been elongated, scale-like structures that lacked the individual barbs seen today. This observation led the describers to postulate that feathers may have been derived from scales by elongation, followed by development of a central shaft. All birds evolved from feathered dinosaurs, and there is thus taxonomic differentiation between birds and dinosaurs. Birds survived the Cretaceous-Tertiary extinction event and the dinosaurs did not.

This specimen shows portions of preserved downy feathers, but not the elongated tail feathers. There is insufficient data to show whether all specimens show these elongated tail feathers. Perhaps, like in its close relative Confuciusornis, only the males developed the elongations. If you look closely at the skull, you can see evidence of teeth; the first specimens found showed at total of four teeth present. Notice too the wings. The wing claws are visible, particularly the alular claws. The alula (or "bastard wing") is a feathered structure which provides modern-day birds with additional lift during slow flight. Neither Confuciusornis nor Archaeopteryx had an alula, and so are thought to have been unable to take off directly from ground level.

A primitive Enantiornithine bird and the origin of feathers, Science, 2000, 290, 1955-1959.