| Protopteryx | |
|---|---|
_NMNS.jpg) | |
| Fossil specimen,National Museum of Natural Science | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Avialae |
| Clade: | †Enantiornithes |
| Order: | †Protopterygiformes Zhang &Zhou, 2006 |
| Family: | †Protopterygidae Zhang & Zhou, 2006 |
| Genus: | †Protopteryx Zhang & Zhou, 2000 |
| Species: | †P. fengningensis |
| Binomial name | |
| †Protopteryx fengningensis Zhang & Zhou, 2000 | |
Protopteryx is anextinctbird and possibly the basalmostenantiornithean, from theCretaceous period.[1] Thetype species isP. fengningensis.[2] It was first discovered in the Sichakou Member of theYixian Formation orHuajiying Formation ofHebei Province, northernChina,[3] dating from 131 Ma ago.[4]Protopteryxhas been found in the Daibeigou formation, as well.[5] The nameProtopteryx means "primitive feather":[6] "proto-" meaning "the first of" and "-pteryx" meaning "feather" or "wing." The name comes from the fact thatProtopteryx feathers are more primitive than those of modern birds, such as the two elongated tail feathers that lackbarbs and rami.[7]
Protopteryx fossils show that they were roughly the same as a today'sstarling.[6] The adult body length ofProtopteryx was about 10 centimetres (3.9 in), excluding the tail feathers.Protopteryx teeth were conical and unserrated, and some teeth had a resorption pit similar to those seen inArchaeopteryx. The body ofProtopteryx 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 12 millimetres (0.47 in). The barbs of the down feathers were laminar instead of hairlike and were frayed at the tips. The most distinctive feature ofProtopteryx 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 toProtopteryx is the redbird-of-paradise. The tail feathers also lack rami on the proximal end of the tail.[8]
Protopteryx is one of the most basal known members of the groupEnantiornithes. It appeared afterArchaeopteryx, one of the most basal birds, andConfuciusornis.[9]Protopteryx is more basal than the speciesEocathayornis[1] andParaprotopteryx.[10]
Protopteryx was discovered in the Sichakou Member of the Hebei province, west of the Liaoning province.[11] The formations whereProtopteryxwas found were the Yixian and Dageibou formations.[12][13] The Sichakou Basin is part of theDaxinganling-Taihangshan Tectonomagmatic Belt and moves in a north-northeast direction. WhenProtopteryx was alive, the Sichakou basin was located at the Hongqiangou-Jiecangou.[11]
Protopteryx lived in theJehol Biota in the Cretaceous period, which contains many of the terrestrial and freshwater vertebrateclades.[14] The teeth of theProtopteryx are similar toArchaeopteryx, suggesting a similar diet.[8]
Protopteryx was adapted for flying and had feathers with features similar to modern birds, as shown by its procoracoid, carina of the sternum, external tuberosity of the humerus, and deltoid crest, which suggestProtopteryx had a modern musculus supercoracoideus and pectoralis.Protopteryx also shares asymmetric wing flight feathers with flying birds, as well asArchaeopteryx andConfuciusornis.[8] The tail feathers ofProtopteryx lack of barbs and rami close to the body,[8] suggesting a use outside of flight, such as display, thermoregulation, or sensory usage.[9]
