Tongtianlong

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Tongtianlong
Temporal range: Late Cretaceous, 66.7  Ma
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Tongtianlong-2.jpg
Holotype skeleton of Tongtianlong limosus
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Family: Oviraptoridae
Genus: Tongtianlong
et al., 2016
Species:
T. limosus
Binomial name
Tongtianlong limosus
Lü et al., 2016

Tongtianlong (meaning "Tongtianyan dragon") is a genus of oviraptorid theropod dinosaurs that lived in the late Maastrichtian epoch of the late Cretaceous period. It contains one species, T. limosus. [1]

Contents

Description

Skull of Tongtianlong limosus Tongtianlong-4-horizontal.png
Skull of Tongtianlong limosus

Tongtianlong was a sheep-sized member of the oviraptorids, a group of omnivorous, feathered, bird-like theropods. [2] The describers of Tongtianlong recognized that it possessed a set of distinctive characteristics that differentiated it both from other oviraptorosaurs. In particular, unlike other oviraptorids, the crest of Tongtianlong was shaped like a dome, with its highest point just behind the eye socket; and the front edge of the toothless premaxilla, which would have supported its beak, was very rounded. [1]

Additionally, there is a distinct ridge on the front margin of the parietal bone, wedged between the frontal bones; the shaft of the lacrimal bone, which is located in front of the eye socket, is wide, flattened, and plate-like seen from the side; the foramen magnum (a hole in the back of the skull) is smaller than the occipital condyle (the boss forming the skull-neck joint); there is no ridge on the bottom of the front lower jaws, which is also not strongly downturned; and the xiphoid process does not flare out from the sternum behind the ribs. Other characteristics of the skull separate Tongtianlong from its contemporaries; for instance, the nostril is situated much higher than the antorbital fenestra, a trait seen otherwise only in Nemegtomaia and Rinchenia . [1]

Discovery and naming

Map of the fossil locality Srep35780-f1.jpg
Map of the fossil locality

The holotype of Tongtianlong, specimen number DYM-2013-8, was discovered during the construction of a new high school near Ganxian District in Jiangxi Province, China. The site where it was found is part of the Nanxiong Formation, which dates to the Maastrichtian epoch (although a more precise dating has not yet been conducted). The specimen is currently stored in the Dongyang Museum. [1] While the exceptionally well-preserved specimen was likely originally complete, portions of the arms, right leg, and tail were destroyed by the TNT blasting which unearthed the fossil. [3] [2] Near the hip, a drill hole that was used to place TNT can be seen. [1]

The skeleton was preserved in an unusual pose, with a raised head and splayed arms; while it is difficult to tell exactly what led to this pose, [1] it has been speculatively suggested that the specimen died while it was trapped in mud and trying to free itself. [2] The genus name of Tongtianlong combines a reference to the nearby Tongtianyan (Chinese :通天岩) grotto and the suffix -long (Chinese :, "dragon"). [4] "Tongtian" also is a Chinese phrase meaning "road to heaven". The specific name, limosus (the Latin word for "muddy"), refers to how the specimen was preserved in mudstone. It was first described and named by Lü Junchang, Chen Rongjun, Stephen L. Brusatte, et al. [1]

Classification

Elements of the holotype Tongtianlong elements.jpg
Elements of the holotype

In 2016, Tongtianlong was found to be a member of the Oviraptoridae, as a close relative of Banji and Wulatelong . The results of the phylogenetic analysis conducted are partially reproduced below. [1]

Oviraptoridae

Nankangia jiangxiensis

Oviraptor philoceratops

Yulong mini

Nomingia mongoliensis

Rinchenia mongoliensis

Zamyn Khondt "Citipati"

Huanansaurus ganzhouensis

Citipati osmolskae

Tongtianlong limosus

Wulatelong gobiensis

Banji long

Shixinggia oblita

Khaan mckennai

Conchoraptor gracilis

Wulatelong gobiensis

Machairasaurus leptonychus

Jiangxisaurus ganzhouensis

Ganzhousaurus nankangensis

Nemegtomaia barsboldi

Ajancingenia yashini

Heyuannia huangi

Paleoecology

Life reconstruction of Tongtianlong limosus, and speculative death conditions Tongtianlong-5.jpg
Life reconstruction of Tongtianlong limosus, and speculative death conditions

Tongtianlong is the sixth oviraptorid described from the Nanxiong Formation, after Banji , Ganzhousaurus , Jiangxisaurus , Nankangia , and Huanansaurus , in that order. Given the variation in size among these oviraptorids (for instance, Banji is much smaller than Tongtianlong), it is reasonable to hypothesize that some of them might be growth stages of others; however, it is more likely that they represent genuinely distinct animals, since juvenile oviraptorid specimens show that their anatomy does not change significantly with age. [5] [1]

The describers of Tongtianlong suggested that this diversity is indicative of an evolutionary radiation of oviraptorids that occurred just prior to the Cretaceous–Paleogene extinction event. [3] However, the possibility that these species come from different points in time cannot be excluded, due to a lack of study on the stratigraphy and age of the Nanxiong Formation. [1]

See also

Related Research Articles

<i>Oviraptor</i> Extinct genus of dinosaurs

Oviraptor is a genus of oviraptorid dinosaur that lived in Asia during the Late Cretaceous period. The first remains were collected from the Djadokhta Formation of Mongolia in 1923 during a paleontological expedition led by Roy Chapman Andrews, and in the following year the genus and type species Oviraptor philoceratops were named by Henry Fairfield Osborn. The genus name refers to the initial thought of egg-stealing habits, and the specific name was intended to reinforce this view indicating a preference over ceratopsian eggs. Despite the fact that numerous specimens have been referred to the genus, Oviraptor is only known from a single partial skeleton regarded as the holotype, as well as a nest of about fifteen eggs and several small fragments from a juvenile.

<i>Byronosaurus</i> Extinct genus of dinosaurs

Byronosaurus is a genus of troodontid dinosaur from the Late Cretaceous Period of Mongolia.

<i>Alioramus</i> Tyrannosaurid theropod dinosaur genus from the Late Cretaceous period

Alioramus is a genus of tyrannosaurid theropod dinosaurs from the Late Cretaceous period of Asia. It currently contains two species. The type species, A. remotus is known from a partial skull and three foot bones recovered from the Mongolian Nemegt Formation, which was 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.

<i>Conchoraptor</i> Extinct genus of dinosaurs

Conchoraptor is a genus of oviraptorid dinosaur from the late Cretaceous Period of what is now Asia.

<i>Citipati</i> Genus of oviraptorid dinosaur from the Late Cretaceous period

Citipati is a genus of oviraptorid dinosaur that lived in Asia during the Late Cretaceous period, about 75 million to 71 million years ago. It is mainly known from the Ukhaa Tolgod locality at the Djadokhta Formation, where the first remains were collected during the 1990s. The genus and type species Citipati osmolskae were named and described in 2001. A second species from the adyacent Zamyn Khondt locality may also exist. Citipati is one of the best-known oviraptorids thanks to a number of well-preserved specimens, including individuals found in brooding positions atop nests of eggs, though most of them were initially referred to the related Oviraptor. These nesting specimens have helped to solidify the link between non-avian dinosaurs and birds.

<i>Sinovenator</i> Extinct genus of dinosaurs

Sinovenator is a genus of troodontid dinosaur from China. It is from the early Cretaceous Period.

<i>Nemegtomaia</i> Oviraptorid dinosaur genus from Late Cretaceous Mongolia

Nemegtomaia is a genus of oviraptorid dinosaur from what is now Mongolia that lived in the Late Cretaceous Period, about 70 million years ago. The first specimen was found in 1996, and became the basis of the new genus and species N. barsboldi in 2004. The original genus name was Nemegtia, but this was changed to Nemegtomaia in 2005, as the former name was preoccupied. The first part of the generic name refers to the Nemegt Basin, where the animal was found, and the second part means "good mother", in reference to the fact that oviraptorids are known to have brooded their eggs. The specific name honours the palaeontologist Rinchen Barsbold. Two more specimens were found in 2007, one of which was found on top of a nest with eggs, but the dinosaur had received its genus name before it was found associated with eggs.

<i>Nanshiungosaurus</i> Extinct genus of reptiles

Nanshiungosaurus is a genus of therizinosaurid that lived in what is now Asia during the Late Cretaceous of South China. The type species, Nanshiungosaurus brevispinus, was first discovered in 1974 and described in 1979 by Dong Zhiming. It is represented by a single specimen preserving most of the cervical and dorsal vertebrae with the pelvis. A supposed and unlikely second species, "Nanshiungosaurus" bohlini, was found in 1992 and described in 1997. It is also represented by vertebrae but this species however, differs in geological age and lacks authentic characteristics compared to the type, making its affinity to the genus unsupported.

<i>Banji</i> Extinct genus of dinosaurs

Banji is an extinct genus of oviraptorid dinosaur that lived approximately 66 million years ago during the later part of the Cretaceous Period in what is now China. It was a small, lightly-built, ground-dwelling, bipedal carnivore, that was an estimated 65 cm (2.1 ft) long, as a juvenile.

Nanxiong Formation

The Nanxiong Formation is a Late Cretaceous geologic formation in Guangdong Province. Dinosaur remains are among the fossils that have been recovered from the formation.

<i>Xixiasaurus</i> Genus of dinosaur

Xixiasaurus is a genus of troodontid dinosaur that lived during the Late Cretaceous Period in what is now China. The only known specimen was discovered in Xixia County, Henan Province, in central China, and became the holotype of the new genus and species Xixiasaurus henanensis in 2010. The names refer to the areas of discovery, and can be translated as "Henan Xixia lizard". The specimen consists of an almost complete skull, part of the lower jaw, and teeth, as well as a partial right forelimb.

<i>Macroolithus</i> Dinosaur egg

Macroolithus is an oogenus of dinosaur egg belonging to the oofamily Elongatoolithidae. The type oospecies, M. rugustus, was originally described under the now-defunct oogenus name Oolithes. Three other oospecies are known: M. yaotunensis, M. mutabilis, and M. lashuyuanensis. They are relatively large, elongated eggs with a two-layered eggshell. Their nests consist of large, concentric rings of paired eggs. There is evidence of blue-green pigmentation in its shell, which may have helped camouflage the nests.

<i>Yulong mini</i> Extinct species of dinosaur

Yulong is an extinct genus of derived oviraptorid theropod dinosaur known from the Late Cretaceous Qiupa Formation of Henan Province, central China. It contains a single species, Yulong mini. It is known from many juvenile specimens that represent some of the smallest known oviraptorids.

<i>Ganzhousaurus</i> Extinct genus of dinosaurs

Ganzhousaurus is an extinct genus of oviraptorine oviraptorid dinosaur known from the Late Cretaceous Nanxiong Formation of Nankang County, Ganzhou City of Jiangxi Province, southern China. It was found in a Maastrichtian deposit and contains a single species, Ganzhousaurus nankangensis. It is distinguished by a combination of primitive and derived features.

<i>Jiangxisaurus</i> Extinct genus of dinosaurs

Jiangxisaurus is an extinct genus of oviraptorid theropod dinosaur from the Late Cretaceous Nanxiong Formation of southern China. It was similar to Heyuannia, but with more strongly curved anterior claws and a thinner, frailer mandible. This find is paleontologically significant because it contributes to current knowledge about the paleogeographical distribution of oviraptorids in southern China. It was most likely a herbivorus animal along with its close relatives Nankangia and Ganzhousaurus.

<i>Nankangia</i> Extinct genus of dinosaurs

Nankangia is an extinct genus of caenagnathoid oviraptorosaurian dinosaur known from the Upper Cretaceous Nanxiong Formation of Nankang County, Ganzhou City of Jiangxi Province, southeastern China. It contains a single species, Nankangia jiangxiensis. N. jiangxiensis coexisted with at least four other caenagnathoids, including an unnamed oviraptorid, Banji long, Ganzhousaurus nankangensis and Jiangxisaurus ganzhouensis. The relatively short dentary and non-downturned mandibular symphysis of Nankangia suggest that it may have been more herbivorous than carnivorous. Its diet consisting of leaves and seeds.

Timeline of oviraptorosaur research

This timeline of oviraptorosaur research is a chronological listing of events in the history of paleontology focused on the oviraptorosaurs, a group of beaked, bird-like theropod dinosaurs. The early history of oviraptorosaur paleontology is characterized by taxonomic confusion due to the unusual characteristics of these dinosaurs. When initially described in 1924 Oviraptor itself was thought to be a member of the Ornithomimidae, popularly known as the "ostrich" dinosaurs, because both taxa share toothless beaks. Early caenagnathid oviraptorosaur discoveries like Caenagnathus itself were also incorrectly classified at the time, having been misidentified as birds.

<i>Huanansaurus</i> Extinct genus of dinosaurs

Huanansaurus is an extinct genus of oviraptorid dinosaur that lived approximately 72 million years ago, between the Campanian and Maastrichtian, during the latter part of the Cretaceous period in what is now China, in the Nanxiong Formation.

<i>Corythoraptor</i> Extinct genus of dinosaurs

Corythoraptor is a genus of oviraptorid dinosaur from the late Maastrichtian Nanxiong Formation of South China. It contains one species, C. jacobsi, known from a single well-preserved skeleton, and named after paleontologist Louis L. Jacobs. It bears a tall crest similar to that of the modern cassowary, and possibly had a similar functionality of display and resonance to detect lower-frequency sounds. Like other oviraptorids, the bones of Corythoraptor were heavily pneumatized with many air pockets. Microanalysis of the bones indicates seasonal growth spurts, and the type specimen probably died at the age of 6 or 7, meaning growth continued into at least the 8th year of development. The type specimen reached 1.6 m in length. Oviraptorids may have predominantly inhabited arid environments and ate xerophytic (drought-resistant) plants, nuts, and seeds. However, Corythoraptor coexisted with six other oviraptorid genera, and they may have all eaten different foods.

Lü Junchang was a Chinese palaeontologist and professor at the Institute of Geology, Chinese Academy of Geological Sciences. An expert on Mesozoic reptiles, he described and named dozens of dinosaur and pterosaur taxa including Tongtianlong, Qianzhousaurus, Heyuannia, Gannansaurus, Yunnanosaurus youngi, and Darwinopterus.

References

  1. 1 2 3 4 5 6 7 8 9 10 Lü, J.; Chen, R.; Brusatte, S.L.; Zhu, Y.; Shen, C. (2016). "A Late Cretaceous diversification of Asian oviraptorid dinosaurs: evidence from a new species preserved in an unusual posture". Scientific Reports. 6: 35780. doi:10.1038/srep35780. PMC   5103654 . PMID   27831542.
  2. 1 2 3 Gill, Victoria (10 November 2016). "Unknown dinosaur almost blown to oblivion". BBC News. Retrieved 10 November 2016.
  3. 1 2 Davis, Nicola (10 November 2016). "New species of 'weird bird'-like dinosaur discovered in China". The Guardian. Retrieved 10 November 2016.
  4. "中国赣州南雄组晚白垩世第6个描述的新窃蛋龙科恐龙——泥潭通天龙" [The sixth new oviraptorosaurian dinosaur from the Late Cretaceous Nanxiong Formation of Ganzhou, China - Tongtianlong limosus]. 化石网 (Fossils Network) (in Chinese). Nanjing: Chinese Academy of Sciences. 11 November 2016. Retrieved 11 November 2016.
  5. Lü, J.; Currie, P.J.; Xu, L.; Zhang, X.; Pu, H.; Jia, S. (2013). "Chicken-sized oviraptorid dinosaurs from central China and their ontogenetic implications". Naturwissenschaften. 100 (2): 165–175. doi:10.1007/s00114-012-1007-0. PMID   23314810.