Yanornis
Yanornis | |
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Fossil specimen of Y. martini | |
Artist's reconstruction of Y. martini | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Clade: | Avialae |
Family: | †Songlingornithidae |
Genus: | †Yanornis Zhou & Zhang, 2001 |
Type species | |
†Yanornis martini Zhou & Zhang, 2001
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Species | |
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Synonyms | |
Yanornis (
Description
Y. martini was the size of a chicken,[3] had a long skull with about 10 teeth in the upper jaw and 20 teeth in the lower jaw, and was both able to fly and walk well, having a well-developed U-shaped furcula (wishbone).
The absence of the
Diet
Several fossil specimens of Y. martini preserve the remains of fish in the stomach and crop, suggesting that these birds were primarily fish-eaters. Their fish-eating and associated adaptations show convergent evolution with the unrelated enantiornithine Longipteryx.[6]
One specimen preserved large amounts of supposed gastroliths ("stomach stones") in the gizzard region. Large numbers of small gastroliths are usually associated with species that need to grind tough plant material, such as seeds, after swallowing them. This led some scientists to suggest that Yanornis was capable of "diet switching", perhaps seasonally, between fish and seeds.[7] However, later studies cast doubt on the diet-switching hypothesis. Further study of the specimen found that the supposed stomach stones were not massed around a single region corresponding with the gizzard, as in other fossils with such stones, including specimens of Archaeorhynchus and Hongshanornis. Rather, the stones were spread throughout the body cavity in a front-to-back arrangement. This has been suggested to correspond more closely with the intestines, and may represent impacted sand. In modern birds, sand is often swallowed accidentally during feeding (particularly when feeding on dead fish), and, due to some obstruction, may eventually become impacted in the intestines, leading to death.[8]
Classification
In a 2006 study of early bird relationships, it was found that Yanornis,
The cladogram below follows O’Connor et al., 2013 phylogenetic analysis. The clade names are positioned based on their definitions (contra O’Connor et al. (2013)).[10]
Euornithes |
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Name and synonyms
The genus name Yanornis is derived from the Ancient Chinese Yan dynasties, whose capital was at Chaoyang, and Ancient Greek ornis, "bird". The species Y. martini was named for avian paleontologist Larry Martin.[6]
Yanornis gained notoriety when the front half of a fossil bird was combined with the tail of a
Some studies have found that the bird species Aberratiodontus wui is in fact a poorly preserved specimen of Yanornis martini, or at least a close relative,[11][12] an opinion which has been supported by subsequent reviews of enantiornithine taxonomy.[13]
References
- ^ S2CID 4423242.
- .
- ^ Holtz, Thomas R. Jr. (2011) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2010 Appendix.
- ^ Senter, Phil (2006). "Scapular orientation in theropods and basal birds, and the origin of flapping flight" (PDF). Acta Palaeontologica Polonica. 51 (2): 305–313.
- ^ a b 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.
- ^ .
- S2CID 20380110.
- PMID 24733485.
- PMID 16533313.
- S2CID 85261944.
- ^ Cau, A.; Arduini, P. (2008). "Enantiophoenix electrophyla gen. et sp. nov. (Aves, Enantiornithes) from the Upper Cretaceous (Cenomanian) of Lebanon and its phylogenetic relationships". Atti della Societa Italiana di Scienze Naturali e del Museo Civico di Storia Naturale in Milano. 149: 293–324.
- PMID 18397240.
- .