Yanornis

• Chaoyang City, Liaoning, China ( Jiufotang Formation)

Yanornis is an extinct bird species that lived during the early Cretaceous period, and a primordial member of the group Ornithurae, who also belong to all modern birds. The description of the nature Yanornis martini based on fossils that were found in the Jiufotang formation in Chaoyang, western Liaoning Province of the People's Republic of China. By 2004, five specimens were known.

Etymology

The neologism Yanornis is derived from the ancient Chinese Yan dynasties, whose capital Chaoyang was from the ancient Greek word όρνις ( ornis ) for birds; the species name was chosen in honor of the martini Paläornithologen Larry D. Martin.

Description

Yanornis reached the size of a full-grown pigeon, the skull was elongated and had 10 teeth in the upper jaw and 20 teeth in the lower jaw. The bird fed mainly on fish. In adaptation to this diet Yanornis acquired some morphological features that are convergent also in the Cretaceous bird Longipteryx that counts for not more closely related group of Enantiornithes formed. Fork leg and teeth but are more like the enantiornithinen genus Aberratiodontus.

The absence of the prefrontal ( anterior prefrontal ) and compared to the pristine Diapsida Skull Anatomy Skull prove very derived Yanornis ' belonging to the Ornithurae, which included the common ancestor of all extant bird species. The wishbone ( furcula ) was U-shaped and derived in its morphology. Also scapula and coracoid were similar already in shape and arrangement of those of modern birds. For this reason Yanornis could raise its wings across the back and perform an efficient surcharge. Compared to the Enantiornithes and basal birds and Archaeopteryx Conficiusornis he had a far better ability to fly. The muscles needed for an energetic flight needed a solid approach surface, so at Yanornis exceeded the length of the sternum whose width - also a modern development trend ..

Taxonomy and systematics

Yanornis gained fame by a paleontological fraud, as the front half of a bird was combined with the tail of a Micro Raptors and then presented as " Archaeoraptor ". After the forgery was obvious the bird half was described as repatriatus Archaeovolans and later identified as belonging Yanornis.

A systematic study in 2006 on the family relationships of modern birds came to the conclusion that Yanornis, Yixianornis and Songlingornis form a monophyletic group - because Songlingornis was the first genus described, the name of this taxon should read Songlingornithidae. That Yanornis is just a synonym for Songlinornis, is not supported by all phylogenetic analyzes.

Footnotes

Swell

• Clarke, Julia A.; Zhou, Zhonghe & Zhang, Fucheng (2006): Insight into the evolution of avian flight from a new clade of Early Cretaceous ornithurines from China and the morphology of Yixianornis grabaui. Journal of Anatomy 208 ( 3) :287 - 308. doi: 10.1111/j.1469-7580.2006.00534.x PDF Electronic Appendix
• Gong, Enpu; Hou, Lianhai & Wang, Lixia (2004): Enantiornithine Bird with Diapsidian Skull and Its Dental Development in the Early Cretaceous in Liaoning, China. Acta Geologica Sinica 78 (1): 1-7. PDF
• Mortimer, Michael ( 2004): The Theropod Database: Phylogeny of taxa. accessed on October 29, 2007.
• Senter, Phil (2006): Scapular orientation in theropods and basal birds, and the origin of flapping flight. Acta Palaeontologica Polonica 51 (2): 305-313. PDF
• Zhou, Zhonghe & Zhang, Fucheng (2001): Two new birds from the Early Cretaceous ornithurine of western Liaoning, China. Chinese Science Bulletin 46 (15): 1258-1264. PDF
• Zhou, Zhonghe; Clarke, Julia A. & Zhang, Fucheng (2002): Archaeoraptor 's better half. Nature 420:285. doi: 10.1038/420285a
• Zhou, Zhonghe; Clarke, Julia A.; Zhang, Fucheng & Wings, O. ( 2004): Gastroliths in Yanornis: an indication of the earliest radical diet -switching and gizzard plasticity in the lineage leading to living birds? . Natural Sciences 91:571-574. PDF

• Aves
• Fossil bird