''Paraprotopteryx'' is a genus of

enantiornithean The Enantiornithes, also known as enantiornithines or enantiornitheans in literature, are a group of extinct avialans ("birds" in the broad sense), the most abundant and diverse group known from the Mesozoic era. Almost all retained teeth and cl ...

birds from the

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Creta ...

of China.Zheng, X. Zhang, Z. & Hou, L. (2007) A new enantiornithine bird with four long rectrices from the Early Cretaceous of northern Hebei, China. ''Acta Geologica Sinica'' 81(5):703-708. In 2007, the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

''Paraprotopeteryx gracilis'' was named and described by

Zheng Xiaoting Zheng may refer to: *Zheng (surname), Chinese surname (鄭, 郑, ''Zhèng'') *Zheng County, former name of Zhengzhou, capital of Henan, China *Guzheng (), a Chinese zither with bridges *Qin Shi Huang (259 BC – 210 BC), emperor of the Qin Dynasty, ...

, Zhang Zihui and Hou Lianhai. The generic name means "near '' Protopteryx''", in reference to a presumed similarity with that genus. The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

is intended to mean "pretty". The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of seve ...

is specimen STM V001. It consists of a skeleton with skull on a plate and counterplate. The investigation preceding the description of the species proved that fossil traders had added the skull of a different individual to the torso. The description is based on the rump parts. Feathers have been preserved. The rump represents a subadult individual. Though initially reported to be from the

Early Cretaceous The Early Cretaceous (geochronological name) or the Lower Cretaceous ( chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pr ...

Yixian Formation The Yixian Formation (; formerly transcribed as Yihsien Formation) is a geological formation in Jinzhou, Liaoning, People's Republic of China, that spans the late Barremian and early Aptian stages of the Early Cretaceous. It is known for its ...

, later investigation showed that the fossil actually came from the Qiaotou Member of the Huajiying Formation of

Fengning Fengning Manchu Autonomous County (; Manchu: ; Mölendroff: fengning manju beye dasangga siyan) is a Manchu autonomous county of northern Hebei province, bordering Beijing to the southwest and Inner Mongolia to the north, and lying under the adm ...

Hebei Province Hebei or , (; alternately Hopeh) is a northern province of China. Hebei is China's sixth most populous province, with over 75 million people. Shijiazhuang is the capital city. The province is 96% Han Chinese, 3% Manchu, 0.8% Hui, and ...

, China, and is therefore of uncertain age. While much of the Huajiying Formation underlies the Yixian Formation,Jin, Zhang, Li, Zhang, Li and Zhou (2008). "On the horizon of ''Protopteryx'' and the early vertebrate fossil assemblages of the Jehol Biota." ''Chinese Science Bulletin'', 53(18): 2820-2827. Ji and colleagues suggested in 2008 that the Qiaotou Member correlates with the Dawangzhangzi beds of the Yixian Formation, dated to approximately 122 million years ago by Zhou Zhonghe in 2006.Zhou, Z. (2006). "Evolutionary radiation of the Jehol Biota: chronological and ecological perspectives." ''Geological Journal'', 41: 377–393.

Distinguishing characteristics

The original description suggested a number of distinguishing traits. ''Paraprotopteryx'' would have had a

furcula The (Latin for "little fork") or wishbone is a forked bone found in most birds and some species of non-avian dinosaurs, and is formed by the fusion of the two pink clavicles. In birds, its primary function is in the strengthening of the Thorax, ...

(wishbone) which is shaped like a Y with a narrow angle between the clavicles. It also was described as having an unusually shaped

breastbone The sternum or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury ...

, distinguishing it from other birds in the Enantiornithines. The carpometacarpus is only partially fused. ''Paraprotopteryx'' has four, ten centimetres long,

rectrices Flight feathers (''Pennae volatus'') are the long, stiff, asymmetrically shaped, but symmetrically paired pennaceous feathers on the wings or tail of a bird; those on the wings are called remiges (), singular remex (), while those on the tai ...

(flight feathers on the tail), more than doubling the total body length, which may represent an important step in feather evolution. They have a very elongated ribbon-like shaft and only the tips are barbed and expanded. In ''Paraprotopteryx'' they may have served as a secondary sex characteristic. This was the first time a tail fan was reported for Enantiornithes. Later such a double pair was reported for '' Shanweiniao''. However, although the presence of two ribbon-like rectrices is certain (as in the related enantiornithean bird ''Protopteryx'') the describers of ''Shanweiniao'' in 2012 voiced a suspicion that the second pair of rectrices in ''Paraprotopteryx'' might be the result of artifice.Jingmai K. O’Connor, Luis M. Chiappe,

Cheng-ming Chuong The rectification of names () is originally a doctrine of feudal Confucian designations and relationships, behaving accordingly to ensure social harmony. Without such accordance society would essentially crumble and "undertakings would not be comp ...

, David J. Bottjer and Hailu You (2012) "Homology and Potential Cellular and Molecular Mechanisms for the Development of Unique Feather Morphologies in Early Birds." ''Geosciences'', 2 157-177.

References

External links

A photograph of the main slab of the type specimen (STM V001), published by Albertonykus's (Albert Chen's) twitter account
Early Cretaceous birds of Asia Enantiornitheans Fossil taxa described in 2007 {{paleo-bird-stub