Biology:Pygostylia
| Pygostylians | |
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| Fossil pygostylian (Confuciusornis sanctus) | |
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| House sparrow (Passer domesticus) | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | Avialae |
| Clade: | Avebrevicauda |
| Clade: | Pygostylia Chatterjee, 1997 |
| Subgroups[2] | |
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Pygostylia is a group of avialans which includes the Confuciusornithidae and all of the more advanced species, the Ornithothoraces.
Definition
The group Pygostylia was intended to encompass all avialans with a short, stubby tail, as opposed to the longer, unfused tails of more primitive species like Archaeopteryx lithographica. It was named by Sankar Chatterjee in 1997.[3] Luis Chiappe later defined Pygostylia as a node-based clade, "the common ancestor of the Confuciusornithidae and Neornithes plus all its descendants".[4][5] In 2001, Jacques Gauthier and Kevin de Queiroz recommended that Chatterjee's original apomorphy-based clade concept be used instead of Chiappe's node-based definition,[6] but this recommendation has been inconsistently followed. Luis Chiappe and co-authors continue to use Chiappe's definition, often attributing authorship of the name to Chiappe 2001[7] or Chiappe 2002[8] rather than to Chatterjee.
Cladogram following the results of a phylogenetic study by Jingmai O'Connor and colleagues in 2016:[2]
| Pygostylia |
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In 2023, Li et al recovered their new taxon, Cratonavis, as the new jinguofortisid that belongs to Pygostylia. The results of their phylogenetic analyses are shown in the cladogram below:[9]
| Avialae |
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Description
Chiappe noted that under his definition, all members of the Pygostylia share four unique characteristics. The trait that gives the group its name is the presence of a pygostyle, or set of fused vertebrae at the end of the tail. Next is the absence of a hyposphene - hypantrum. Next is a reversed pubic bone separated from the main axis of the sacrum by an angle of 45 to 65 degrees. Last is a bulbous medial condyle of the tibiotarsus (lower leg bone).[4]
The pygostylians fall into two distinct groups with regard to the pygostyle. The Ornithothoraces have a ploughshare-shaped pygostyle, while the more primitive members had longer, rod-shaped pygostyles.
The earliest known member of the group is the enantiornithine species Protopteryx fengningensis, from the Sichakou Member of the Huajiying Formation of China , which dates to around 131 Ma ago,[10] though at least one other enantiornithine, Noguerornis, may be even older, at up to 145.5 million years ago, though its exact age is uncertain.[11]
References
- ↑ Wang M., Wang X., Wang Y., and Zhou Z. (2016). A new basal bird from China with implications for morphological diversity in early birds. Scientific Reports, 6: 19700. doi:10.1038/srep19700.
- ↑ 2.0 2.1 O’Connor, J.K., Wang X., Zheng X., Hu H., Zhang X., & Zhou Z. (2016). An Enantiornithine with a Fan-Shaped Tail, and the Evolution of the Rectricial Complex in Early Birds. Current Biology, 26(1): 114-119.
- ↑ Chatterjee, S. 1997. The Rise of Birds. Baltimore: Johns Hopkins University Press. 312 pp.
- ↑ 4.0 4.1 Chiappe, Luis (2001). Chiappe, Luis; Witmer. eds. Basal bird phylogeny in Mesozoic Birds: above the heads of dinosaurs. University of California Press.
- ↑ Chiappe, L. (1997). "The Chinese early bird Confuciusornis and the paraphyletic status of Sauriurae". Journal of Vertebrate Paleontology 17 (3): 37A. doi:10.1080/02724634.1997.10011028.
- ↑ Gauthier, J., & De Queiroz, K. (2001). Feathered dinosaurs, flying dinosaurs, crown dinosaurs, and the name" Aves. New perspectives on the origin and early evolution of birds, 7-41.
- ↑ Gao, C.; Chiappe, L. M.; Zhang, F.; Pomeroy, D. L.; Shen, C.; Chinsamy, A.; Walsh, M. O. (2012). "A subadult specimen of the Early Cretaceous birdSapeornis chaoyangensisand a taxonomic reassessment of sapeornithids". Journal of Vertebrate Paleontology 32 (5): 1103. doi:10.1080/02724634.2012.693865.
- ↑ O’Connor, J. K.; Zhang, Y.; Chiappe, L. M.; Meng, Q.; Quanguo, L.; Di, L. (2013). "A new enantiornithine from the Yixian Formation with the first recognized avian enamel specialization". Journal of Vertebrate Paleontology 33: 1–12. doi:10.1080/02724634.2012.719176.
- ↑ Li, Zhiheng; Wang, Min; Stidham, Thomas A.; Zhou, Zhonghe (2023-01-02). "Decoupling the skull and skeleton in a Cretaceous bird with unique appendicular morphologies" (in en). Nature Ecology & Evolution 7 (1): 20–31. doi:10.1038/s41559-022-01921-w. ISSN 2397-334X. PMID 36593291. https://www.nature.com/articles/s41559-022-01921-w.
- ↑ O'Connor, J.K., Zhou Z. and Zhang F., 2011. A reappraisal of Boluochia zhengi (Aves: Enantiornithes) and a discussion of intraclade diversity in the Jehol avifauna, China. Journal of Systematic Palaeontology, (published online before print 16 December 2010). doi:10.1080/14772019.2010.512614
- ↑ Holtz, Thomas R. Jr. (2012) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages, Winter 2011 Appendix.
Wikidata ☰ Q135800 entry
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