Paraprotopteryx

Paraprotopteryx is a genus of enantiornithine birds. Though initially reported to be from the Early Cretaceous Yixian Formation, later investigation showed the fossil actually came from the Qiaotou member of the Huajiying Formation of Fengning, Hebei Province, China, and is therefore of uncertain age. While much of the Huajiying Formation underlies the Yixian Formation, Ji and colleagues suggested in 2008 that the Qiaotou Member correlates with the Dawangzhangzi bed of the Yixian Formation, dated to ~122 Ma ago by Zhou in 2006.

Paraprotopteryx has a furcula (wishbone) which is shaped like a Y with a narrow angle between the clavicles. It also has an unusually shaped breastbone, distinguishing it from other birds in its suborder, the enantiornithines. The carpometacarpus is only partially fused.

It has four long rectrices (flight feathers on the tail), which may represent an important step in feather evolution. For comparison, most modern birds have twelve rectrices; grouse often have more than twelve, while grebes have none. In Paraprotopteryx they may have served as a secondary sex characteristic. However, although the presence of two ribbon-like rectrices is certain (as in the related enantiornithine bird Protopteryx) there is a suspicion that the second pair of rectrices might be the result of artifice.