Gigantoraptor

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Gigantoraptor
Temporal range: Late Cretaceous,
~96  Ma
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Gigantoraptor.jpg
Mounted reconstructed skeleton of Gigantoraptor in Japan
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Superfamily:† Caenagnathoidea
Family:† Caenagnathidae
Genus:† Gigantoraptor
Xu et al., 2007
Type species
†Gigantoraptor erlianensis
Xu et al., 2007

Gigantoraptor (lit. 'giant thief') is a genus of large oviraptorosaur dinosaur that lived in Asia during the Late Cretaceous period. It is known from the Iren Dabasu Formation of Inner Mongolia, where the first remains were found in 2005.

Gigantoraptor was the largest-known oviraptorosaur, reaching 8 metres (26 ft) in length and 2 metric tons (2.2 short tons) in body mass. It had an extensively pneumatized vertebral column and elongated arms and legs. Both femur and tibia measured over 1 m (3.3 ft) in length, an unusual trait among giant theropods. The lower jaws were toothless and ended in a keratinous beak, as seen in other oviraptorosaurs. Though several oviraptorosaur species are known to have developed a full coat of feathers, Gigantoraptor, due to its size, could have lost some of this integument.

The genus is classified as an oviraptorosaurian dinosaur, a group of generally small feathered animals. Though it was originally found to represent a basal oviraptorid, subsequent analyses have shown it to be a caenagnathid. It was a giant, ground-dwelling bipedal omnivore or herbivore with a shearing bite as indicated by the preserved mandible. The shape of its beak indicates a generalist diet with a potentially occasional carnivory. The holotype—and only known specimen—has been determined to represent a young adult that died at the age of 11, and it reached a young adulthood around 7 years of life. Such development indicates an accelerated growth compared to other larger theropods. The discovery and examination of large oviraptorosaur eggs, Macroelongatoolithus , indicates that large species such as Gigantoraptor built their nests with the center lacking eggs in order to avoid crushing.

History of discovery

A manual ungual of the holotype Gigantoraptor claw.jpg
A manual ungual of the holotype

In a quarry at Saihangaobi, Iren Dabasu Formation, Erlian basin, Sonid Left Banner (Inner Mongolia), numerous remains of the sauropod Sonidosaurus have been uncovered since 2001. Chinese paleontologist Xu Xing was asked to reenact the discovery of Sonidosaurus in April 2005 for a Japanese documentary. Xu obliged them by digging out a thighbone. As he wiped the bone clean, he suddenly realized it was not from a sauropod, but from an unidentified theropod in the size class of Albertosaurus . He then stopped the filming to secure the serendipitous find. This way, the discovery of the Gigantoraptor holotype fossil was documented on film. [1] [2]

In 2007, the type species Gigantoraptor erlianensis was named and described by Xu, Tan Qingwei, Wang Jianmin, Zhao Xijin and Tan Lin. The generic name, Gigantoraptor, is derived from the Latin gigas, gigantis, meaning "giant" and raptor, meaning "seizer". The specific name, erlianensis, refers to the Erlian basin. [1] The holotype, LH V0011, consists of the incomplete and disassociated remains of a single adult individual, preserving a nearly complete mandible, a partial isolated cervical vertebra, dorsal vertebrae, caudal vertebrae, right scapula, right humerus, right radius and ulna, nearly complete right manus, partial ilium with a nearly complete pubis and hindlimbs, including both femur, tibia and fibula with a very complete pes. [1] It is currently housed at the Longhao Institute of Geology and Paleontology. [3]

Holotype lower jaw of Gigantoraptor (top) compared to dentary of MPC-D 107/17 (bottom) LH V0011 & MPC-D 107 17 lower jaws.png
Holotype lower jaw of Gigantoraptor (top) compared to dentary of MPC-D 107/17 (bottom)

In 2015 Takanobu Tsuihiji with team reported a partial—and large—caenagnathid dentary (specimen MPC-D 107/17) from the Bayan Shireh Formation, discovered in 2008 by the Hayashibara Museum of Natural Sciences-Mongolian Paleontological Center Joint Expedition, at the Tsagaan Teg locality. As preserved, the dentary is virtually similar to that of Gigantoraptor in both morphology and size. Despite shared traits between Gigantoraptor and MPC-D 107/17, and their close relationships, Tsuihiji and team regarded it as Caenagnathidae indet. due to its fragmentary nature. [4] Authors Rubén Molina-Pérez and Asier Larramendi in 2019 assigned this partial dentary as cf. Gigantoraptor erlianensis, suggesting that it could represent an additional specimen. [5]

Description

Gigantoraptor size (holotype) compared to a 1.8-metre-tall (5.9 ft) human Gigantoraptor scale.png
Gigantoraptor size (holotype) compared to a 1.8-metre-tall (5.9 ft) human

Gigantoraptor is the largest known oviraptorosaur for which skeletal material is available. Approximately three times as long and 35 times heavier than the largest earlier-discovered oviraptorosaur Citipati , the holotype of Gigantoraptor has been estimated at 8 m (26 ft) long with a height of 3.5 m (11 ft) at the hips, and a ponderous weight of 1.4 metric tons (1.5 short tons). [1] Other studies have estimated its body mass at approximately or more than 2 t (2.2 short tons). [6] [7] [8]

Oviraptorosaurs are fairly known to have developed feathers, as seen on feathered specimens of Caudipteryx and the pygostyle of several oviraptorids. [1] [9] As an oviraptorosaur, Gigantoraptor was likely feathered as well, however, given its massive size it may have been partially naked. [1]

Skull

Holotype mandible in right lateral view Gigantoraptor lower jaw (right side).png
Holotype mandible in right lateral view

As preserved, the total length of the lower jaws is 46 cm (460 mm), and they are toothless. This element fused into a broad shovel-like shape, indicating that the unknown skull was over half a metre long and also toothless, likely equipped with a rhamphotheca (horny beak). Compared to the right side, the left side of the jaws is well-preserved with an almost intact shape. The dentary bones are very deep and toothless, and have a pair of sharply-developed shelves on the top edges. These structures are relatively flat. The anterior end of the dentary is rounded, more similar to caenagnathids and different from the chin-shaped one of some oviraptorids. From a top view, the symphyseal (bone union) region at the front of the dentary is U-shaped. Along the lateral surfaces of this bone, some nutrient foramina can be found, which likely supported a rhamphotheca. [3]

Gigantoraptor lower jaw.png
Gigantoraptor lower jaw (anterior posterior sides).png
Holotype mandible in lateral, dorsal, anterior and posterior views

Both angular and articular-surangular-coronoid (ASC) complex are comparatively smaller than the dentary. The angular is firmly fused to the ASC complex and gives form to the lower margin of the external mandibular fenestra. The angular has a bowed shape and is mainly forwards extended with a large lateral depression that joints with the posterior lower process (bony projection/extension) of the dentary. The ASC complex is composed by the fusion of the articular and surangular bones with the coronoid process of the mandible. This complex extends forwards to articulate with the posterior upper process of the dentary and gives form to the upper margin of the external mandibular fenestra. The coronoid process prominence is low and distinctively rounded. On the posterior end of the mandibles the articular glenoid can be located. It is relatively large, convex, and bowl-shaped. [3]

Postcranial skeleton

Skeletal reconstruction of the holotype, known remains in white Gigantoraptor erlianensis skeletal.png
Skeletal reconstruction of the holotype, known remains in white

The anterior caudal vertebrae have very long neural spines and are heavily pneumaticised with deep pleurocoels. The middle section of the relatively short tail is somewhat stiffened by long prezygapophyses. The caudal vertebrae are heavily pneumatized with a spongeous-like bone filling. The forelimbs are rather long because of an elongated humerus (73.5 cm (2.41 ft) long) and slender manus. The humerus is bowed outwards to an exceptionally large extent and has a very rounded head, similar to some birds. The first metacarpal is very short and carries a strongly diverging thumb. The hindlimbs are well-developed and highly elongated: the femur is slender with a distinct head and neck, measuring 1.1 m (3.6 ft); the tibia has similar top and bottom borders and measures 1.10 m (3.6 ft) long; and the metatarsus is 58.3 cm (1.91 ft) long with the metatarsal III being the largest. The pes is robust with large and strongly curved pedal unguals. [1] [10]

Classification

In 2007, Xu and team assigned Gigantoraptor to the Oviraptoridae, in a basal (primitive) position. The anatomy of Gigantoraptor includes the diagnostic features of the Oviraptorosaurs. However, it also includes several features found in more derived eumaniraptoran dinosaurs, such as a forelimb/hindlimb ratio of 60%, a lack of expansion of the distal scapula and the lack of a fourth trochanter on the femur. Despite its size, Gigantoraptor would thus have been more bird-like than its smaller oviraptorosaurian relatives. [1]

In 2010, a second analysis of Gigantoraptor relationships found it to be a member of the Caenagnathidae rather than an oviraptorid. [11] Phylogenetic analysis conducted by Lamanna et al. (2014), supported that Gigantoraptor was a basal caenagnathid. [12]

Comparison between the manus of Gigantoraptor (D) and other caenagnathoids Oviraptorosaur manus.png
Comparison between the manus of Gigantoraptor (D) and other caenagnathoids

The cladogram below follows the phylogenetic analysis conducted by Funston & Currie in 2016, which found Gigantoraptor to be a caenagnathid. [13]

Caenagnathidae

Paleobiology

Feathers

Life restoration Gigantoraptor Restoration.png
Life restoration

Xu and team in 2007 suggested that Gigantoraptor might have been partially "naked" because it is 300 times as heavy as feathered species like Caudipteryx , and large animals tend to rely more on body mass for temperature regulation, leading to the loss of insulating coverings found on their smaller relatives. However, they suggested that at least arm feathers were probably still present on Gigantoraptor, since their primary functions, such as display behaviour and covering the eggs while brooding, are not related to the regulation of body heat. [1]

Ontogeny and development

A histological analysis performed on the holotype fibula by Xu and colleagues in 2007 showed that the specimen had seven lines of arrested growth (LAGs, or growth rings) as preserved. As several LAGs were missing, the team used inverse calculations to determine them, resulting in a total of 11. The amount of LAGs indicate the holotype was around 11 years old at the time of death and had an average growth of 128–140 kg (282–309 lb) per year. The performed histology also suggests that this individual was an adult, as there was extensive development of the secondary osteons, tightly packed LAGs close to the periphery of the bone, and a poorly vascularized layer of lamellar bone in the outer circumferential layer, which indicates a relatively sloppy growth rate. However, given that the fourth to seventh sets of LAGs were not very tightly packed, Xu and colleagues inferred that the individual reached its young adulthood at the age of 7. Moreover, the specimen was found to still be a relatively young adult and thereby it would have grown larger when it reached the adult stage. This indicates that Gigantoraptor had a growth rate much faster than most large non-avian theropods, such as tyrannosaurids. [1]

Another unusual development in Gigantoraptor are the elongated hindlimbs. Xu and colleagues pointed out the larger the theropod becomes, the shorter and stockier the legs become in order to withstand the increasing mass. This is contrasted by Gigantoraptor with both femur and tibia being over 1 m (3.3 ft), a combination that is not usually found in theropods of this size. The elongation of these limbs indicates that it was one of the most cursorial—an animal adapted to run or maintain certain speed for a large amount of time—large theropods. Furthermore, Gigantoraptor had an extensively pneumatized vertebral column, which may have aided in weight loss. [1]

Feeding

Lower jaw of the holotype Gigantoraptor lower jaw (left side).png
Lower jaw of the holotype

In 2017, Waisum Ma and colleagues re-examined the preserved jaws of Gigantoraptor and found that it had the deepest beak among caenagnathids and a relatively different diet from other oviraptorosaurs. For instance, the articular region of the jaws of Gigantoraptor show convergence to those of the modern tuatara. The articular region in this reptile enables propalinal jaw movement (a forward and backward movement) during feeding, and based on the similarities between their jaws, Ma and colleagues suggested that Gigantoraptor could have employed propalinal jaw movement as well. This movement aided with the sharp shelves of the dentary may indicate a shearing bite capable of cutting through plants (and potentially meat). This is comparable to other caenagnathids and contrasting with the jaws of oviraptorids, whose jaws seem better suited for crushing food. The depth of the lower jaw indicates the presence of a large tongue, which could have assisted the animal in food processing, and possibly improving the feeding efficiency. [3]

As the shape and size of the rostrum in large herbivores is related to dietary habits, the strongly U-shaped dentary of Gigantoraptor may suggest that this oviraptorosaur was a highly non-selective feeder, an adaptation that could have been useful in the variable environmental settings of the Iren Dabasu Formation. The team based this hypothesis on comparisons with several herbivorous animals, including other dinosaurs. Whereas sharply developed and narrow rostra are more correlated with a selective diet, such as the case of some ceratopsians, wide and rounded rostra are more linked with a generalist diet, as seen on the morphology of Gigantoraptor, Euoplocephalus and hadrosaurids. Ma and colleagues also pointed out that its large size, and therefore greater energy requirements, could have influenced its dietary habits as larger animals tend to consume lower-quality food since it is available in larger amounts on the surroundings, and has a more stable supply. However, it is not known whether the gut of Gigantoraptor was specialized to process this greater ingestion. The team could not disregard an occasional carnivorous diet as the strong beak together with a propalinal jaw movement may have allowed meat processing. [3]

Reproduction

Fossilized Macroelongatoolithus nest from Zhengzhou, featuring the large center region devoid of eggs Fossil Dinosaur Eggs- Macroelongatoolithus xixiaensis.jpg
Fossilized Macroelongatoolithus nest from Zhengzhou, featuring the large center region devoid of eggs

The existence of giant oviraptorosaurians, such as Gigantoraptor, explains several earlier Asian finds of very large, up to ~50 cm (20 in) long, oviraptorosaurian eggs, assigned to the oospecies Macroelongatoolithus carlylensis. These were laid in enormous rings with a diameter of three metres. The presence of Macroelongatoolithus in North America indicates that gigantic oviraptorosaurs were present there as well, though no fossil skeletal remains have been found. [14] The 2017 description and naming of Beibeilong —based on an embryonic individual associated with eggs—further supports that Macroelongatoolithus eggs and nests belong to colossal caenagnathid oviraptorosaurs, such as Gigantoraptor. [15]

In 2018, Kohei Tanaka and team examined the egg clutches of numerous oviraptorosaur specimens, including egg clutches of Macroelongatoolithus, in order to correlate the nest configuration and body size to incubation behaviour. Their results showed that eggshell porosity indicates that the eggs of almost certainly all oviraptorosaurs were exposed in the nest without an external covering. Though most oviraptorosaur nests have eggs arranged in a circular fashion, the morphology of the nest is different in smaller and larger species in that the center of the nest is highly reduced in the former species, and becomes significantly larger in the latter species. This nest configuration suggest that whereas smallest oviraptorosaurs probably sat directly on the eggs, a large, Gigantoraptor-sized animal likely sat on the area devoid of eggs. Tanaka and colleagues pointed out that this adaption was beneficial to avoid egg-crushing and could have allowed some body contact during incubation in these giant oviraptorosaurs. [16]

Paleoenvironment

Restoration of a Gigantoraptor pair protecting their nest from two Archaeornithomimus and an Alectrosaurus Gigantoraptor and Alectrosaurus.jpg
Restoration of a Gigantoraptor pair protecting their nest from two Archaeornithomimus and an Alectrosaurus

Gigantoraptor is known from the Iren Dabasu Formation of Inner Mongolia. This formation has been dated to 95.8 ± 6.2 million years ago based on U–Pb and stratigraphic analyses. [17] The environments around this formation were highly humid, existing as a large braided river valley with floodplains. A semi-arid climate is also indicated by caliche-based sedimentation. The Iren Dabasu Formation had extensive vegetation and foliage, evidenced in the paleosol development, the numerous herbivorous dinosaurs remains that were found in both the river channel and the floodplain sediments. A rich diversity of charophytes and ostracods inhabited the floodplain systems. [18]

The dinosaurian fauna of this formation includes the fast-running tyrannosauroid Alectrosaurus , the ornithomimosaur Archaeornithomimus , the therizinosaurids Erliansaurus and Neimongosaurus , the sauropod Sonidosaurus , and hadrosauroids Bactrosaurus and Gilmoreosaurus . [19] [20] Both Iren Dabasu and Bayan Shireh formations have been correlated on the basis of their similar vertebrate fossil record. This correlation may be further supported by the presence of a giant, Gigantoraptor-sized caenagnathid in the Bayan Shireh Formation. The presence of the Bayan Shireh caenagnathid and Gigantoraptor in fluvial-based sedimentation formations like the Iren Dabasu and Bayan Shireh formations suggest a preference over mesic habitats in giant oviraptorosaur species, rather than xeric habitats. [4]

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>Segnosaurus</i> Extinct genus of therizinosaurid dinosaur from late Cretaceous

Segnosaurus is a genus of therizinosaurid dinosaur that lived in what is now southeastern Mongolia during the Late Cretaceous, about 102–86 million years ago. Multiple incomplete but well-preserved specimens were discovered in the Gobi Desert in the 1970s, and in 1979 the genus and species Segnosaurus galbinensis were named. The generic name Segnosaurus means "slow lizard" and the specific name galbinensis refers to the Galbin region. The known material of this dinosaur includes the lower jaw, neck and tail vertebrae, the pelvis, shoulder girdle, and limb bones. Parts of the specimens have gone missing or become damaged since they were collected.

<span class="mw-page-title-main">Oviraptoridae</span> Extinct family of dinosaurs

Oviraptoridae is a group of bird-like, herbivorous and omnivorous maniraptoran dinosaurs. Oviraptorids are characterized by their toothless, parrot-like beaks and, in some cases, elaborate crests. They were generally small, measuring between one and two metres long in most cases, though some possible oviraptorids were enormous. Oviraptorids are currently known only from the Late Cretaceous of Asia, with the most well-known species and complete specimens found only in the Gobi Desert of Mongolia and northwestern China.

<span class="mw-page-title-main">Oviraptorosauria</span> Extinct clade of dinosaurs

Oviraptorosaurs are a group of feathered maniraptoran dinosaurs from the Cretaceous Period of what are now Asia and North America. They are distinct for their characteristically short, beaked, parrot-like skulls, with or without bony crests atop the head. They ranged in size from Caudipteryx, which was the size of a turkey, to the 8-meter-long, 1.4-ton Gigantoraptor. The group is close to the ancestry of birds. Some researchers such as Maryanska et al (2002) and Osmólska et al. (2004) have proposed that they may represent primitive flightless birds. The most complete oviraptorosaur specimens have been found in Asia. The North American oviraptorosaur record is sparse.

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

Alectrosaurus is a genus of tyrannosauroid theropod dinosaur that lived in Asia during the Late Cretaceous period, about some 96 million years ago in what is now the Iren Dabasu Formation.

<i>Caenagnathasia</i> Extinct species of reptile

Caenagnathasia is a small caenagnathid oviraptorosaurian theropod from the Late Cretaceous of Uzbekistan.

<span class="mw-page-title-main">Bayan Shireh Formation</span> Geological formation in Mongolia

The Bayan Shireh Formation is a geological formation in Mongolia, that dates to the Cretaceous period. It was first described and established by Vasiliev et al. 1959.

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

Hagryphus is a monospecific genus of caenagnathid dinosaur from southern Utah that lived during the Late Cretaceous in what is now the Kaiparowits Formation of the Grand Staircase–Escalante National Monument. The type and only species, Hagryphus giganteus, is known only from an incomplete but articulated left manus and the distal portion of the left radius. It was named in 2005 by Lindsay E. Zanno and Scott D. Sampson. Hagryphus has an estimated length of 2.4–3 metres and weight of 50 kilograms.

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

Caenagnathus is a genus of caenagnathid oviraptorosaurian dinosaur from the late Cretaceous period. It is known from partial remains including lower jaws, a tail vertebra, hand bones, and hind limbs, all found in the Dinosaur Park Formation of Alberta, Canada. Caenagnathus measured about 2.5 m (8.2 ft) long and weighed about 96–100 kg (212–220 lb).

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

Heyuannia is a genus of oviraptorid dinosaur that lived in Asia during the Late Cretaceous epoch, in what is now China and Mongolia. It was the first oviraptorid found in China; most others were found in neighbouring Mongolia. Two species are known: H. huangi, named by Lü Junchang in 2002 from the Dalangshan Formation; and H. yanshini, originally named as a separate genus Ingenia from the Barun Goyot Formation by Rinchen Barsbold in 1981, and later renamed to Ajancingenia in 2013 due to the preoccupation of Ingenia. The latter name was eventually discarded due to various ethical issues surrounding the author.

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

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.

<span class="mw-page-title-main">Caenagnathidae</span> Extinct family of dinosaurs

Caenagnathidae is a family of derived caenagnathoid dinosaurs from the Cretaceous of North America and Asia. They are a member of the Oviraptorosauria, and relatives of the Oviraptoridae. Like other oviraptorosaurs, caenagnathids had specialized beaks, long necks, and short tails, and would have been covered in feathers. The relationships of caenagnathids were long a puzzle. The family was originally named by Raymond Martin Sternberg in 1940 as a family of flightless birds. The discovery of skeletons of the related oviraptorids revealed that they were in fact non-avian theropods, and the discovery of more complete caenagnathid remains revealed that Chirostenotes pergracilis, originally named on the basis of a pair of hands, and Citipes elegans, originally thought to be an ornithomimid, named from a foot, were caenagnathids as well.

The Iren Dabasu Formation is a Late Cretaceous geologic formation in the Iren Nor region of Inner Mongolia. Dinosaur remains diagnostic to the genus level are among the fossils that have been recovered from the formation. The formation was first described and defined by Henry Fairfield Osborn in 1922 and it is located in the Iren Nor region of China.

<i>Macroelongatoolithus</i> Oogenus of dinosaur egg

Macroelongatoolithus is an oogenus of large theropod dinosaur eggs, representing the eggs of giant caenagnathid oviraptorosaurs. They are known from Asia and from North America. Historically, several oospecies have been assigned to Macroelongatoolithus, however they are all now considered to be a single oospecies: M. carlylensis.

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

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.

<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 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.

<span class="mw-page-title-main">Timeline of oviraptorosaur research</span>

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.

<span class="mw-page-title-main">Elongatoolithidae</span> Oofamily of dinosaur eggs

Elongatoolithidae is an oofamily of fossil eggs, representing the eggs of oviraptorosaurs. They are known for their highly elongated shape. Elongatoolithids have been found in Europe, Asia, and both North and South America.

<i>Tsagandelta</i> Extinct family of mammals

Tsagandelta is a genus of deltatheroidean therian mammal that lived in Asia during the Late Cretaceous. Distantly related to modern marsupials, it is part of Deltatheroida, a lineage of carnivorous metatherians common in the Cretaceous of Asia and among the most successful non-theropod carnivores of the region. It represents the first known mammal from the Bayan Shireh Formation.

<i>Beibeilong</i> Caenagnathid dinosaur genus from the Late Cretaceous

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.

References

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  3. 1 2 3 4 5 Ma, W.; Wang, J.; Pittman, M.; Tan, Q.; Tan., L.; Guo, B.; Xu, X. (2017). "Functional anatomy of a giant toothless mandible from a bird-like dinosaur: Gigantoraptor and the evolution of the oviraptorosaurian jaw". Scientific Reports. 7 (1): 16247. Bibcode:2017NatSR...716247M. doi: 10.1038/s41598-017-15709-7 . PMC   5701234 . PMID   29176627.
  4. 1 2 Tsuihiji, T.; Watabe, M.; Barsbold, R.; Tsogtbaatar, K. (2015). "A gigantic caenagnathid oviraptorosaurian (Dinosauria: Theropoda) from the Upper Cretaceous of the Gobi Desert, Mongolia". Cretaceous Research. 56: 60−65. doi:10.1016/j.cretres.2015.03.007.
  5. ↑ Molina-Pérez, R.; Larramendi, A. (2019). Dinosaur Facts and Figures: The Theropods and Other Dinosauriformes. Princeton: Princeton University Press. p. 54. doi:10.1515/9780691190594. ISBN   9788416641154. JSTOR   j.cdb2hnszb. S2CID   198839986.
  6. ↑ Paul, Gregory S. (2010). "Theropods". The Princeton Field Guide to Dinosaurs. Princeton: Princeton University Press. p. 152. doi:10.1515/9781400836154.67b. ISBN   9781400836154.
  7. ↑ Campione, N. E.; Evans, D. C.; Brown, C. M.; Carrano, M. T. (2014). "Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions". Methods in Ecology and Evolution. 5 (9): 913−923. doi: 10.1111/2041-210X.12226 . hdl:10088/25281.
  8. ↑ Benson, R. B. J.; Campione, N. E.; Carrano, M. T.; Mannion, P. D.; Sullivan, C.; Upchurch, P.; Evans, D. C. (2014). "Rates of Dinosaur Body Mass Evolution Indicate 170 Million Years of Sustained Ecological Innovation on the Avian Stem Lineage". PLOS Biology. 12 (6): e1001896. doi: 10.1371/journal.pbio.1001853 . hdl:10088/25994. PMC   4011683 . PMID   24802911.
  9. ↑ Persons, W. Scott, IV; Currie, Philip J.; Norell, Mark A. (2014). "Oviraptorosaur tail forms and functions". Acta Palaeontologica Polonica. doi: 10.4202/app.2012.0093 .{{cite journal}}: CS1 maint: multiple names: authors list (link)
  10. ↑ 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. Bibcode:2013NW....100..165L. doi:10.1007/s00114-012-1007-0. PMID   23314810. S2CID   206871470.
  11. ↑ Longrich, N. R.; Currie, P. J.; Zhi-Ming, D. (2010). "A new oviraptorid (Dinosauria: Theropoda) from the Upper Cretaceous of Bayan Mandahu, Inner Mongolia". Palaeontology. 53 (5): 945–960. doi: 10.1111/j.1475-4983.2010.00968.x .
  12. ↑ Lamanna, M. C.; Sues, H. D.; Schachner, E. R.; Lyson, T. R. (2014). "A New Large-Bodied Oviraptorosaurian Theropod Dinosaur from the Latest Cretaceous of Western North America". PLOS ONE. 10 (4): e0125843. doi: 10.1371/journal.pone.0092022 . PMC   3960162 . PMID   24647078.
  13. ↑ Funston, G.; Currie, P. J. (2016). "A new caenagnathid (Dinosauria: Oviraptorosauria) from the Horseshoe Canyon Formation of Alberta, Canada, and a reevaluation of the relationships of Caenagnathidae". Journal of Vertebrate Paleontology. 36 (4): e1160910. doi:10.1080/02724634.2016.1160910. S2CID   131090028.
  14. ↑ Simon, D. J. (2014). "Giant Dinosaur (Theropod) eggs of the Oogenus Macroelongatoolithus (Elongaroolithidae) from Southeastern Idaho: Taxonimic, Paleobiogeographic, and Reproductive implications" (PDF).{{cite journal}}: Cite journal requires |journal= (help)
  15. ↑ Pu, H.; Zelenitsky, D. K.; Lü, J.; Currie, P. J.; Carpenter, K.; Xu, L.; Koppelhus, E. B.; Jia, S.; Xiao, L.; Chuang, H.; Li, T.; Kundrát, M.; Shen, C. (2017). "Perinate and eggs of a giant caenagnathid dinosaur from the Late Cretaceous of central China". Nature Communications. 8 (14952): 14952. doi: 10.1038/ncomms14952 . PMC   5477524 . PMID   28486442.
  16. ↑ Tanaka, K.; Zelenitsky, D. K.; Lü, J.; DeBuhr, C. L.; Yi, L.; Jia, S.; Ding, F.; Xia, M.; Liu, D.; Shen, C.; Chen, R. (2018). "Incubation behaviours of oviraptorosaur dinosaurs in relation to body size". Biology Letters. 14 (5): 20180135. doi: 10.1098/rsbl.2018.0135 . PMC   6012691 . PMID   29769301.
  17. ↑ Guo, Z. X.; Shi, Y. P.; Yang, Y. T.; Jiang, S. Q.; Li, L. B.; Zhao, Z. G. (2018). "Inversion of the Erlian Basin (NE China) in the early Late Cretaceous: Implications for the collision of the Okhotomorsk Block with East Asia" (PDF). Journal of Asian Earth Sciences. 154: 49−66. doi:10.1016/j.jseaes.2017.12.007. Archived from the original (PDF) on 19 September 2020. Retrieved 1 May 2020.
  18. ↑ Van Itterbeeck, J.; Horne, D. J.; Bultynck, P.; Vandenberghe, N. (2005). "Stratigraphy and palaeoenvironment of the dinosaur-bearing Upper Cretaceous Iren Dabasu Formation, Inner Mongolia, People's Republic of China". Cretaceous Research. 26 (4): 699−725. doi:10.1016/j.cretres.2005.03.004.
  19. ↑ Currie, P. J.; Eberth, D. A. (1993). "Palaeontology, sedimentology and palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner Mongolia, People's Republic of China". Cretaceous Research. 14 (2): 127−144. doi:10.1006/cres.1993.1011.
  20. ↑ Xing, H.; He, Y.; Li, L.; Xi, D. (2012). "A review on the study of the stratigraphy, sedimentology, and paleontology of the Iren Dabasu Formation, Inner Mongolia". In Wei, D. (ed.). Proceedings of the Thirteenth Annual Meeting of the Chinese Society of Vertebrate Paleontology (in Chinese). Beijing: China Ocean Press. pp. 1−44.
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