Protopteryx

Protopteryx is an extinct bird and possibly the basalmost enantiornithean, from the Cretaceous period. The type species is P. fengningensis. It was first discovered in the Sichakou Member of the Yixian Formation or Huajiying Formation of Hebei Province, northern China, dating from 131 Ma ago. Protopteryx has been found in the Daibeigou formation, as well. The name Protopteryx means "primitive feather": "proto-" meaning "the first of" and "-pteryx" meaning "feather" or "wing." The name comes from the fact that Protopteryx feathers are more primitive than those of modern birds, such as the two elongated tail feathers that lack barbs and rami.

== Description == Protopteryx fossils show that they were roughly the same as a today's starling. The adult body length of Protopteryx was about , excluding the tail feathers. Protopteryx teeth were conical and unserrated, and some teeth had a resorption pit similar to those seen in Archaeopteryx. The body of Protopteryx was covered in three types of feathers: down feathers, flight feathers, and long, ribbon-like tail feathers. The body was mostly covered in feathers of about . The barbs of the down feathers were laminar instead of hairlike and were frayed at the tips. The most distinctive feature of Protopteryx is that the tail consisted of two long feathers which only had barbs at their tips. Closer to the body, the long tail feathers were thin and needle-like. The only modern bird to share a feather type similar to Protopteryx is the red bird-of-paradise. The tail feathers also lack rami on the proximal end of the tail.