Dilong paradoxus

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]

Dilong paradoxus
Temporal range: Early Cretaceous, 126 Ma
Dilong skeleton mount at TyrannosaursMeettheFamily
Skeleton cast mount at Des Moines Science Center
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Clade: Pantyrannosauria
Genus: Dilong
Xu et al., 2004
Species:
D. paradoxus
Binomial name
Dilong paradoxus
Xu et al., 2004

Discovery

Dilong
Type specimen

Dilong was described by Xu Xing and colleagues in 2004.[3] The name is derived from the Chinese 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 Latinisation of the Ancient Greek παράδοξον meaning 'against received wisdom'.

Description

Dilong paradoxus size 01
Size comparison between Dilong and a human

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

Dilong TJV 50
Life restoration

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.[4] 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.[5]

Below is a cladogram containing most tyrannosauroids by Loewen et al. in 2013.[6]

Tyrannosauroidea
Proceratosauridae

Proceratosaurus bradleyi

Kileskus aristotocus

Guanlong wucaii

Sinotyrannus kazuoensis

Juratyrant langhami

Stokesosaurus clevelandi

Dilong paradoxus

Eotyrannus lengi

Bagaraatan ostromi

Raptorex kriegsteini

Dryptosaurus aquilunguis

Alectrosaurus olseni

Xiongguanlong baimoensis

Appalachiosaurus montgomeriensis

Alioramus altai

Alioramus remotus

Tyrannosauridae

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.[7]

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.[8]

See also

References

  1. ^ 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.
  2. ^ 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.
  3. ^ Xu, X.; Norell, M. A.; Kuang, X.; Wang, X.; Zhao, Q.; Jia, C. (2004). "Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids" (PDF). Nature. 431 (7009): 680–684. doi:10.1038/nature02855. PMID 15470426. Archived from the original (PDF) on 2012-04-02. Retrieved 2011-05-11.
  4. ^ 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)
  5. ^ 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.
  6. ^ 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.
  7. ^ 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.
  8. ^ 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

Alectrosaurus

Alectrosaurus (; meaning "alone lizard") is a genus of tyrannosauroid theropod dinosaur that lived approximately 83 to 74 million years ago during the latter part of the Cretaceous Period in what is now Mongolia. It was a medium-sized, moderately-built, ground-dwelling, bipedal carnivore, with a body shape similar to its much larger relative, Tyrannosaurus rex, and could grow up to an estimated 5 m (16.4 ft) long.

Alioramus

Alioramus (; meaning 'different branch') is a genus of tyrannosaurid theropod dinosaurs from the Late Cretaceous period of Asia. The type species, A. remotus, is known from a partial skull and three foot bones recovered from Mongolian sediments which were deposited in a humid floodplain about 70 million years ago. These remains were named and described by Soviet paleontologist Sergei Kurzanov in 1976. A second species, A. altai, known from a much more complete skeleton, was named and described by Stephen L. Brusatte and colleagues in 2009. Its relationships to other tyrannosaurid genera are unclear, with some evidence supporting a hypothesis that Alioramus is closely related to the contemporary species Tarbosaurus bataar. A possible third species, A. sinensis was described in 2014 on the basis of fossils found in the Nanxiong Formation of China.Alioramus were bipedal like all known theropods, and their sharp teeth indicate that they were carnivores. Known specimens were smaller than other tyrannosaurids like Tarbosaurus bataar and Tyrannosaurus rex, but their adult size is difficult to estimate since both Alioramus species are known only from juvenile or sub-adult remains. The recent discovery of Qianzhousaurus indicates that it belongs to a distinct branch of tyrannosaur. The genus Alioramus is characterized by a row of five bony crests along the top of the snout, a greater number of teeth than any other genus of tyrannosaurid, and a lower skull than most other tyrannosaurids.

Appalachiosaurus

Appalachiosaurus ( ap-ə-LAY-chee-o-SAWR-əs; "Appalachian lizard") is a genus of tyrannosauroid theropod dinosaur from the Late Cretaceous Period of eastern North America. Like almost all theropods, it was a bipedal predator. Only a juvenile skeleton has been found, representing an animal over 7 meters (23 ft) long and weighing over 600 kilograms (1300 lb), which indicates an adult would have been even larger. It is the most completely known theropod from the eastern part of North America.

Fossils of Appalachiosaurus were found in central Alabama, from the Demopolis Chalk Formation. This formation dates to the middle of the Campanian stage of the Late Cretaceous, or around 77 million years ago. Fossil material assigned to A. montegomeriensis is also known from the Donoho Creek and Tar Heel-Coachman formations of North and South Carolina.

Bagaraatan

Bagaraatan (/'ba-ɣa-raa-tan/ meaning 'small' baɣa + 'carnivorous animal, beast of prey' araatan in Mongolian) is a genus of theropod dinosaur from the Late Cretaceous period. Its fossils were found in the Nemegt Formation of Mongolia. Bagaraatan may have been around 3 to 4 metres (9.8 to 13 ft) in length.

The type species, B. ostromi, was described by Osmolska in 1996. The post-cranial (ZPAL MgD-I/108) skeleton has been described as "bird-like", while the skull exhibits features of several different theropod groups.

Daliansaurus

Daliansaurus (meaning "Dalian reptile") is a genus of small troodontid theropod dinosaur, measuring approximately 1 metre (3 ft 3 in) long, from the Early Cretaceous of China. It contains a single species, D. liaoningensis, named in 2017 by Shen and colleagues from a nearly complete skeleton preserved in three dimensions. Daliansaurus is unusual in possessing an enlarged claw on the fourth digit of the foot, in addition to the "sickle claw" found on the second digit of the feet of most paravians. It also has long metatarsal bones, and apparently possesses bird-like uncinate processes (a first among troodontids). In the Lujiatun Beds of the Yixian Formation, a volcanically-influenced region with a cold climate, Daliansaurus lived alongside its closest relatives - Sinovenator, Sinusonasus, and Mei, with which it forms the group Sinovenatorinae.

Dilong

Dilong (traditional Chinese: 地龍; simplified Chinese: 地龙; pinyin: dìlóng; Wade–Giles: ti-lung; lit. "earth dragon") is a Chinese dragon name that is also used to mean "earthworm" in traditional Chinese medicine and Geosaurus in zoological nomenclature.

Dilong (disambiguation)

Dilong is a Chinese dragon name that is also used to mean "earthworm".

Dilong or Di Long may also refer to:

Di Long (extract), a "Lumbricus rubellus earthworm" preparation in traditional Chinese medicine

Dilong paradoxus, a genus of small proceratosaurid tyrannosauroid dinosaur

Dilong (Mokokchung), a ward in Mokokchung, Nagaland, India

Ti Lung (born 1946), Hong Kong actor

Dryptosaurus

Dryptosaurus ( DRIP-toh-SOR-əs) is a genus of tyrannosauroid that lived approximately 67 million years ago during the latter part of the Cretaceous period in what is now New Jersey. Dryptosaurus was a large, bipedal, ground-dwelling carnivore, that could grow up to 7.5 m (25 ft) long. Although largely unknown now outside of academic circles, a famous painting of the genus by Charles R. Knight made it one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel C. Marsh in 1877, Dryptosaurus is among the first theropod dinosaurs known to science.

Eotyrannus

Eotyrannus (meaning "dawn tyrant") is a genus of tyrannosauroid theropod dinosaur hailing from the Early Cretaceous Wessex Formation beds, included in Wealden Group, located in the southwest coast of the Isle of Wight, United Kingdom. The remains (MIWG1997.550), consisting of assorted skull, axial skeleton and appendicular skeleton elements, from a juvenile or subadult, found in a plant debris clay bed, were described by Hutt et al. in early 2001. The etymology of the generic name refers to the animals classification as an early tyrannosaur or "tyrant lizard", while the specific name honors the discoverer of the fossil.

Juratyrant

Juratyrant (meaning "Jurassic tyrant") is a tyrannosauroid dinosaur genus from the late Jurassic period (early Tithonian age) of England. The genus contains a single species, J. langhami.

Kileskus

Kileskus (meaning lizard in the Khakas language) is a genus of tyrannosauroid dinosaur known from partial remains found in Middle Jurassic (Bathonian stage) Itat Formation of Krasnoyarsk Krai, Russia. Fossils recovered include the holotype maxilla, a premaxilla, a surangular, and a few bones from the hand and foot. The skull bones are similar to those of Proceratosaurus. The type species is K. aristotocus. Kileskus was named in 2010 by Averianov and colleagues.

List of non-avian dinosaur species preserved with evidence of feathers

Several non-avian dinosaurs were feathered. Direct evidence of feathers exists for the following species, listed in the order currently accepted evidence was first published. In all examples, the evidence described consists of feather impressions, except those genera inferred to have had feathers based on skeletal or chemical evidence, such as the presence of quill knobs (the anchor points for wing feathers on the forelimb) or a pygostyle (the fused vertebrae at the tail tip which often supports large feathers).

Ostromia crassipes (1970)

Avimimus portentosus (inferred 1987: ulnar ridge)

Sinosauropteryx prima (1996)

Fulicopus lyellii, an ichnotaxon, possible squatting Dilophosaurus or similar. (1996)

Protarchaeopteryx robusta (1997)

GMV 2124 (1997)

Caudipteryx zoui (1998)

Rahonavis ostromi (inferred 1998: quill knobs; possibly avialan)

Shuvuuia deserti (1999)

Beipiaosaurus inexpectus (1999)

Sinornithosaurus millenii (1999)

Caudipteryx dongi (2000)

Caudipteryx sp. (2000)

Microraptor zhaoianus (2000)

Nomingia gobiensis (inferred 2000: pygostyle)

Psittacosaurus sp.? (2002)

Scansoriopteryx heilmanni (2002; possibly avialan)

Yixianosaurus longimanus (2003)

Dilong paradoxus (2004)

Pedopenna daohugouensis (2005; possibly avialan)

Jinfengopteryx elegans (2005)

Juravenator starki (2006)

Sinocalliopteryx gigas (2007)

Velociraptor mongoliensis (inferred 2007: quill knobs)

Epidexipteryx hui (2008; possibly avialan)

Similicaudipteryx yixianensis (inferred 2008: pygostyle; confirmed 2010)

Anchiornis huxleyi (2009; possibly avialan)

Tianyulong confuciusi? (2009)

Concavenator corcovatus? (inferred 2010: quill knobs?)

Xiaotingia zhengi (2011; possibly avialan)

Yutyrannus huali (2012)

Sciurumimus albersdoerferi (2012)

Ornithomimus edmontonicus (2012)

Ningyuansaurus wangi (2012)

Eosinopteryx brevipenna (2013; possibly avialan)

Jianchangosaurus yixianensis (2013)

Aurornis xui (2013; possibly avialan)

Changyuraptor yangi (2014)

Kulindadromeus zabaikalicus? (2014)

Citipati osmolskae (inferred 2014: pygostyle)

Conchoraptor gracilis (inferred 2014: pygostyle)

Deinocheirus mirificus? (inferred 2014: pygostyle)

Yi qi (2015)

Ornithomimus sp. (2015)

Zhenyuanlong suni (2015)

Dakotaraptor steini (inferred 2015: quill knobs)

Apatoraptor pennatus (inferred 2016: quill knobs)

Jianianhualong tengi (2017)

Serikornis sungei (2017)

Caihong juji (2018)

Xingtianosaurus ganqi (2019)

Ambopteryx longibrachium (2019)Note that the filamentous structures in some ornithischian dinosaurs (Psittacosaurus, Tianyulong and Kulindadromeus) and the pycnofibres found in some pterosaurs may or may not be homologous with the feathers of theropods.

Proceratosaurus

Proceratosaurus is a genus of small-sized (~3 metres (9.8 ft) long) carnivorous theropod dinosaur from the Middle Jurassic (Bathonian) of England. It was originally thought to be an ancestor of Ceratosaurus, due to the similar small crest on its snout. Now, however, it is considered a coelurosaur, specifically one of the earliest known members of the clade Tyrannosauroidea.The type specimen is held in the Natural History Museum in London and was recovered in 1910 at Minchinhampton while excavating for a reservoir.

Raptorex

Raptorex is a dubious genus of tyrannosaurid dinosaur. Its fossil remains consist of a single juvenile specimen probably uncovered in Mongolia, or possibly northeastern China. The type species is R. kriegsteini, described in 2009 by Sereno and colleagues. The genus name is derived from Latin raptor, "robber", and rex, "king". The specific name honours Roman Kriegstein, a survivor of the Holocaust, whose son Henry Kriegstein donated the specimen to the University of Chicago for scientific study.While initially considered to have come from the Yixian Formation of China, dated to approximately 125 million years ago during the early Cretaceous period, later studies showed that such an early date for the fossil are unlikely, and given its extremely close similarity to juvenile tyrannosaurids of the late Cretaceous, it probably came from the Iren Dabasu or similar formation. Because the specimen is a juvenile, and the changes undergone by tyrannosaurids during growth are not yet well understood, many researchers now consider it to be a nomen dubium, because it cannot be confidently paired with an adult skeleton (though it is extremely similar to juvenile Tarbosaurus bataar skeletons of the same size and age).

Sinotyrannus

Sinotyrannus (meaning "Chinese tyrant") is a genus of large basal proceratosaurid dinosaur, a relative of tyrannosaurids which flourished in North America and Asia during the Jurassic and early Cretaceous periods. Sinotyrannus is known from a single incomplete fossil specimen including a partial skull, from the Early Cretaceous Jiufotang Formation of Liaoning, China. Though it is not much younger than primitive tyrannosauroids such as Dilong, it is similar in size to later forms such as Tyrannosaurus. It was much larger than contemporary tyrannosauroids; reaching a total estimated length of 9–10 m (30–33 ft), it is the largest known theropod from the Jiufotang Formation. The type species is S. kazuoensis, described by Ji et al., in 2009.

Stokesosaurus

Stokesosaurus (meaning "Stokes' lizard") is a genus of small (around 3 to 4 meters (10 to 13 ft) in length), carnivorous early tyrannosauroid theropod dinosaurs from the late Jurassic period of Utah, United States.

Timeline of tyrannosaur research

This timeline of tyrannosaur research is a chronological listing of events in the history of paleontology focused on the tyrannosaurs, a group of predatory theropod dinosaurs that began as small, long-armed bird-like creatures with elaborate cranial ornamentation but achieved apex predator status during the Late Cretaceous as their arms shrank and body size expanded. Although formally trained scientists did not begin to study tyrannosaur fossils until the mid-19th century, these remains may have been discovered by Native Americans and interpreted through a mythological lens. The Montana Crow tradition about thunder birds with two claws on their feet may have been inspired by isolated tyrannosaurid forelimbs found locally. Other legends possibly inspired by tyrannosaur remains include Cheyenne stories about a mythical creature called the Ahke, and Delaware stories about smoking the bones of ancient monsters to have wishes granted.Tyrannosaur remains were among the first dinosaur fossils collected in the United States. The first of these was named Deinodon horridus by Joseph Leidy. However, as this species was based only on teeth the name would fall into disuse. Soon after, Edward Drinker Cope described Laelaps aquilunguis from a partial skeleton in New Jersey. Its discovery heralded the realization that carnivorous dinosaurs were bipeds, unlike the lizardlike megalosaurs sculpted for the Crystal Palace. Laelaps was also among the first dinosaurs to be portrayed artistically as a vigorous, active animal, presaging the Dinosaur Renaissance by decades. Later in the century, Cope's hated rival Othniel Charles Marsh would discover that the name Laelaps had already been given to a parasitic mite, and would rename the dinosaur Dryptosaurus.Early in the 20th century, Tyrannosaurus itself was discovered by Barnum Brown and named by Henry Fairfield Osborn, who would recognize it as a representative of a distinct family of dinosaurs he called the Tyrannosauridae. Tyrannosaur taxonomy would be controversial for many decades afterward. One controversy centered around the use of the name Tyrannosauridae for this family, as the name "Deinodontidae" had already been proposed. The name Tyrannosauridae came out victorious following arguments put forth by Dale Russell in 1970. The other major controversy regarding tyrannosaur taxonomy was the family's evolutionary relationships. Early in the history of paleontology, it was assumed that the large carnivorous dinosaurs were all part of one evolutionary lineage ("carnosaurs"), while the small carnivorous dinosaurs were part of a separate lineage (coelurosaurs). Tyrannosaurid anatomy led some early researchers like Matthew, Brown, and Huene, to cast doubt on the validity of this division. However, the traditional carnosaur-coelurosaur division persisted until the early 1990s, when the application of cladistics to tyrannosaur systematics confirmed the doubts of early workers and found tyrannosaurs to be large-bodied coelurosaurs.Another debate about tyrannosaurs would not be settled until the early 21st century: their diet. Early researchers were so overwhelmed by the massive bulk of Tyrannosaurus that some, like Lawrence Lambe, were skeptical that it was even capable of hunting down live prey and assumed that it lived as a scavenger. This view continued to be advocated into the 1990s by Jack Horner but was shown false by Kenneth Carpenter, who reported the discovery of a partially healed tyrannosaur bite wound on an Edmontosaurus annectens tail vertebra, proving that T. rex at least sometimes pursued living victims.

Tyrannosauroidea

Tyrannosauroidea (meaning 'tyrant lizard forms') is a superfamily (or clade) of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe, Asia, South America and Australia.

Tyrannosauroids were bipedal carnivores, as were most theropods, and were characterized by numerous skeletal features, especially of the skull and pelvis. Early in their existence, tyrannosauroids were small predators with long, three-fingered forelimbs. Late Cretaceous genera became much larger, including some of the largest land-based predators ever to exist, but most of these later genera had proportionately small forelimbs with only two digits. Primitive feathers have been identified in fossils of two species, and may have been present in other tyrannosauroids as well. Prominent bony crests in a variety of shapes and sizes on the skulls of many tyrannosauroids may have served display functions.

Xiongguanlong

Xiongguanlong ("Grand Pass dragon") is a genus of tyrannosauroid dinosaur that lived in the Early Cretaceous of what is now China. The type species is X. baimoensis, described online in 2009 by a group of researchers from China and the United States, and formally published in January 2010. The genus name refers to the city of Jiayuguan, a city in northwestern China. The specific name is derived from bai mo, "white ghost", after the "white ghost castle", a rock formation near the fossil site. The fossils include a skull, vertebrae, a right ilium and the right femur. The rocks it was found in are from the Aptian to Albian stages of the Cretaceous, between 125 and 100 million years ago.

Coeluridae?
Proceratosauridae
Pantyrannosauria

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