Tongtianlong Temporal range: Late Cretaceous, | |
---|---|
![]() | |
Holotype skeleton of Tongtianlong limosus | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | † Oviraptoridae |
Genus: | † Tongtianlong Lü 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]
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]
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 :龍, "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]
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 |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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]
Troodontidae is a clade of bird-like theropod dinosaurs. During most of the 20th century, troodontid fossils were few and incomplete and they have therefore been allied, at various times, with many dinosaurian lineages. More recent fossil discoveries of complete and articulated specimens, have helped to increase understanding about this group. Anatomical studies, particularly studies of the most primitive troodontids, like Sinovenator, demonstrate striking anatomical similarities with Archaeopteryx and primitive dromaeosaurids, and demonstrate that they are relatives comprising a clade called Paraves.
Byronosaurus is a genus of troodontid dinosaur from the Late Cretaceous Period of Mongolia.
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 also from the Nemegt Formation, was named and described by Stephen L. Brusatte and colleagues in 2009. Its relationships to other tyrannosaurid genera were at first unclear, with some evidence supporting a hypothesis that Alioramus was closely related to the contemporary species Tarbosaurus bataar. However, the discovery of Qianzhousaurus indicates that it belongs to a distinct branch of tyrannosaurs, namely the tribe Alioramini.
Microhadrosaurus is a genus of hadrosaurid dinosaur from the Campanian or Maastrichtian-age Upper Cretaceous Yuanpu Formation of Guangdong, China. Although its name identifies it as a small hadrosaur, it is based on juvenile remains, and the size of the adult hadrosaur is unknown.
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.
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.
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.
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.
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.
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.
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 and also a single subadult specimen.
Ganzhousaurus is an extinct genus of 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.
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 herbivorous animal along with its close relatives Nankangia and Ganzhousaurus.
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 but not limited to Corythoraptor, Banji, Ganzhousaurus and Jiangxisaurus. The relatively short dentary and non-downturned mandibular symphysis of Nankangia suggest that it may have been more herbivorous than carnivorous. Its diet consisted of leaves and seeds.
Qianzhousaurus is a genus of tyrannosaurid dinosaur that lived in Asia during the Maastrichtian age of the Late Cretaceous period. There is currently only one species named, the type species Qianzhousaurus sinensis, which is a member of the tribe Alioramini and most closely related to Alioramus, the only other known alioramin.
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.
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.
Beibeilong is a genus of large caenagnathid dinosaurs that lived in Asia during the Late Cretaceous epoch, about 96 million to 88 million years ago. The genus contains a single species, Beibeilong sinensis. The species was named and described in 2017 through analysis of an embryonic skeleton and partial nest with large eggs that were discovered in the Gaogou Formation of China between 1992 and 1993.
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.
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.