Dilong paradoxus: Difference between revisions
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'''''Dilong''''' (帝龍, which means 'emperor dragon') is a [[genus]] of basal [[Tyrannosauroidea|tyrannosauroid]] [[dinosaur]].<ref name=JP14>{{Cite journal|author1=Juan D. Porfiri |author2=Fernando E. Novas |author3=Jorge O. Calvo |author4=Federico L. Agnolín |author5=Martín D. Ezcurra |author6=Ignacio A. Cerda |year=2014 |title=Juvenile specimen of ''Megaraptor'' (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation |journal=Cretaceous Research |volume=51 |pages=35–55 |doi=10.1016/j.cretres.2014.04.007 }}</ref> The only species is ''Dilong paradoxus''. It is from the [[Early Cretaceous|Lower]] [[Cretaceous]] [[Yixian Formation]] near Lujiatun, Beipiao, in the western [[Liaoning]] province of [[China]]. It lived about 126 million years ago.<ref name="dating">{{cite journal | last1 = Chang | first1 = S.-C. | last2 = Gao | first2 = K.-Q. | last3 = Zhou | first3 = Z.-F. | last4 = Jourdan | first4 = F. | date = 2017 | title = New chronostratigraphic constraints on the Yixian Formation with implications for the Jehol Biota | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | doi = 10.1016/j.palaeo.2017.09.026 | volume = 487 | pages = 399–406}}</ref> |
'''''Dilong''''' (帝龍, which means 'emperor dragon') is a [[genus]] of basal [[Tyrannosauroidea|tyrannosauroid]] [[dinosaur]].<ref name=JP14>{{Cite journal|author1=Juan D. Porfiri |author2=Fernando E. Novas |author3=Jorge O. Calvo |author4=Federico L. Agnolín |author5=Martín D. Ezcurra |author6=Ignacio A. Cerda |year=2014 |title=Juvenile specimen of ''Megaraptor'' (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation |journal=Cretaceous Research |volume=51 |pages=35–55 |doi=10.1016/j.cretres.2014.04.007 }}</ref> The only species is ''Dilong paradoxus''. It is from the [[Early Cretaceous|Lower]] [[Cretaceous]] [[Yixian Formation]] near Lujiatun, Beipiao, in the western [[Liaoning]] province of [[China]]. It lived about 126 million years ago.<ref name="dating">{{cite journal | last1 = Chang | first1 = S.-C. | last2 = Gao | first2 = K.-Q. | last3 = Zhou | first3 = Z.-F. | last4 = Jourdan | first4 = F. | date = 2017 | title = New chronostratigraphic constraints on the Yixian Formation with implications for the Jehol Biota | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | doi = 10.1016/j.palaeo.2017.09.026 | volume = 487 | pages = 399–406}}</ref> |
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==Discovery== |
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''Dilong'' was described by [[Xu Xing (paleontologist)|Xu Xing]] and colleagues in 2004.<ref name="xuetal2004">{{cite journal |author1=Xu, X. |author2=Norell, M. A. |author3=Kuang, X. |author4=Wang, X. |author5=Zhao, Q. |author6=Jia, C. | year = 2004 | title = Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids | journal = Nature| volume = 431 | pages = 680–684 | doi = 10.1038/nature02855 | pmid = 15470426 | issue = 7009 | url=http://www.geo.arizona.edu/geo3xx/geo308/FoldersOnServer/2004/nature02855.pdf}}</ref> The name is derived from the [[Chinese language|Chinese]] 帝 ''dì'' meaning 'emperor' and 龙 / 龍 ''lóng'' meaning 'dragon'. "Di", "emperor", refers to the relationship of this animal to ''[[Tyrannosaurus]] rex'', the "king" tyrannosaurid. "Long" is used to name Chinese dinosaurs in much the same way that the Latin ''-saur(us)'' is in the West. The specific name, ''paradoxus'', is a [[Latin]]isation of the [[Ancient Greek]] παράδοξον meaning 'against received wisdom'. |
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==Description== |
==Description== |
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Revision as of 15:01, 10 July 2019
| Dilong paradoxus Temporal range: Early Cretaceous,
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| Skeleton cast mount at Des Moines Science Center | |
Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | †Pantyrannosauria |
| Genus: | †Dilong Xu et al., 2004 |
| Species: | †D. paradoxus
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| Binomial name | |
| †Dilong paradoxus Xu et al., 2004
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Dilong (帝龍, which means 'emperor dragon') is a genus of basal tyrannosauroid dinosaur.[1] The only species is Dilong paradoxus. It is from the Lower Cretaceous Yixian Formation near Lujiatun, Beipiao, in the western Liaoning province of China. It lived about 126 million years ago.[2]
Description
The type specimen is IVPP 14243 (Institute of Vertebrate Paleontology and Paleoanthropology in Beijing), a nearly complete, semi-articulated, skull and skeleton. Referred material includes IVPP 1242, a nearly complete skull and presacral vertebrae, TNP01109 (Tianjin Museum of Natural History), a partial skull, and IVPP V11579, another skull which may belong to D. paradoxus, or to a related species. The type specimen of Dilong was about 1.6 m (5.2 ft) in length, but it is thought to be a juvenile and may have been over 2 m (6.6 ft) long when fully grown.
Feathers
Dilong paradoxus had a covering of simple feathers or protofeathers. The feathers were seen in fossilized skin impressions from near the jaw and tail. They are not identical to modern bird feathers, lacking a central shaft and most likely used for warmth, since they could not have enabled flight. Adult tyrannosaurs, found in Alberta and Mongolia have skin impressions which appear to show the pebbly scales typical of other dinosaurs. Xu et al. (2004) speculated that the tyrannosauroids may have had different skin coverings on different parts of their bodies—perhaps mixing scales and feathers. They also speculated that feathers may correlate negatively with body size—that juveniles may have been feathered, then shed the feathers and expressed only scales as the animal became larger and no longer needed insulation to stay warm.
Classification
When Dilong was first described, it was considered one of the earliest and most primitive members of Tyrannosauroidea, the group that includes the later, larger tyrannosaurids such as Tyrannosaurus rex. At least one later study, by Turner and colleagues in 2007, reanalyzed the relationships of coelurosaurian dinosaurs, including Dilong, and found that it was not a tyrannosauroid. Rather, they placed Dilong two steps above the tyrannosauroids in their phylogeny; more advanced than Coelurus, but more primitive than the Compsognathidae.[3] However, other studies continued to find Dilong as a tyrannosauroid, and some (such as Carr & Williamson 2010) found Dilong to fall within Tyrannosauroidea, not among the more advanced coelurosaurs.[4]
Below is a cladogram containing most tyrannosauroids by Loewen et al. in 2013.[5]
In a 2014 study, Dilong was found to be a proceratosaurid.[1] However, in an analysis by Brusatte et al. in 2016, both parsimony and Bayesian phylogenetic analyses placed Dilong outside of Proceratosauridae, as a slightly more advanced tyrannosauroid.[6]
Paleobiology
Braincase scans indicate that Dilong had an S-shaped brain protected by thin meninges, unlike Tyrannosaurus which has a more linear brain protected by thicker meninges; this is probably a size-related trait, as it is in crocodilians. The large flocculus of Dilong suggests it was agile and had good balance, while small olfactory tracts suggest that its sense of smell was not as refined as that of Tyrannosaurus and other more advanced tyrannosauroids.[7]
See also
References
- ^ a b Juan D. Porfiri; Fernando E. Novas; Jorge O. Calvo; Federico L. Agnolín; Martín D. Ezcurra; Ignacio A. Cerda (2014). "Juvenile specimen of Megaraptor (Dinosauria, Theropoda) sheds light about tyrannosauroid radiation". Cretaceous Research. 51: 35–55. doi:10.1016/j.cretres.2014.04.007.
- ^ Chang, S.-C.; Gao, K.-Q.; Zhou, Z.-F.; Jourdan, F. (2017). "New chronostratigraphic constraints on the Yixian Formation with implications for the Jehol Biota". Palaeogeography, Palaeoclimatology, Palaeoecology. 487: 399–406. doi:10.1016/j.palaeo.2017.09.026.
- ^ Turner, A.H., Pol, D., Clarke, J.A., Erickson, G.M., and Norell, M. (2007). "Supporting online material for: A basal dromaeosaurid and size evolution preceding avian flight". Science, 317: 1378-1381. doi:10.1126/science.1144066 (supplement)
- ^ Carr T.D.; Williamson T.E. (2010). "Bistahieversor sealeyi, gen. et sp. nov., a new tyrannosauroid from New Mexico and the origin of deep snouts in Tyrannosauroidea". Journal of Vertebrate Paleontology. 30 (1): 1–16. doi:10.1080/02724630903413032.
- ^ Loewen, M.A.; Irmis, R.B.; Sertich, J.J.W.; Currie, P. J.; Sampson, S. D. (2013). Evans, David C (ed.). "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". PLoS ONE. 8 (11): e79420. doi:10.1371/journal.pone.0079420. PMC 3819173. PMID 24223179.
{{cite journal}}: CS1 maint: unflagged free DOI (link) - ^ Brusatte, Stephen L.; Carr, Thomas D. (2016-02-02). "The phylogeny and evolutionary history of tyrannosauroid dinosaurs". Scientific Reports. 6 (1). doi:10.1038/srep20252. ISSN 2045-2322. PMC 4735739.
- ^ Kundrát, Martin; Xu, Xing; Hančová, Martina; Gajdoš, Andrej; Guo, Yu; Chen, Defeng (2018). "Evolutionary disparity in the endoneurocranial configuration between small and gigantic tyrannosauroids". Historical Biology: 1–15. doi:10.1080/08912963.2018.1518442.
External links
- Original Nature article as a PDF
- New Scientist news article
- Nature news article
- Mounted Dilong skeleton
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