Citipati
Citipati | |
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Nesting Citipati specimen nicknamed "Big Mama", at the American Museum of Natural History | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Family: | †Oviraptoridae |
Subfamily: | †Oviraptorinae |
Genus: | †Citipati Clark et al., 2001 |
Type species | |
†Citipati osmolskae Clark et al., 2001
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Citipati (.
Citipati was among the largest oviraptorids; it is estimated to have been around 2.5–2.9 m (8.2–9.5 ft) in length and to have weighed 75–83 kg (165–183 lb). Its skull was highly
The taxon is classified as an oviraptorid, a group of very bird-like feathered dinosaurs that had robust, parrot-like jaws. It is among the oviraptorid species that preserve nesting specimens. Citipati laid
History of discovery
In 1993, a small fossilized oviraptorid embryo, labelled as specimen IGM 100/971, was discovered in a nest at the Ukhaa Tolgod locality of the highly fossiliferous
During the same year 1993, expeditions of the paleontological project of the Mongolian Academy of Sciences-American Museum of Natural History discovered a large adult oviraptorid specimen also from the Ukhaa Tolgod locality of the Djadokhta Formation, in a sublocality known as Ankylosaur Flats. This new specimen was labelled under the specimen number IGM 100/979 and includes a partial skeleton comprising some ribs and partial limbs but lacking the skull, neck and tail. It was found in a nesting pose, sitting atop a nest of
In 1995, the Mongolian Academy of Sciences-American Museum of Natural History expedition discovered a second nesting oviraptorid specimen from the Ukhaa Tolgod locality, in a region called Camel's Humps, at the Death Row sublocality. This new specimen was labelled as IGM 100/1004 and nicknamed "Big Auntie".
In 2001, the
Description of specimens
Though the first specimen of Citipati (IGM 100/971) was briefly reported and discussed, Norell and colleagues in 2001 provided an extensive description of this specimen. As the description was published prior to the formal naming of Citipati, Norell and team tentatively referred this small embryo to a "new large species from Ukhaa Tolgod"—in fact, later known as Citipati osmolskae—based on the shared tall premaxilla morphology among specimens.[9] The more famous IGM 100/979 was extensively described by Clark and team in 1999, also prior to the naming of Citipati. They considered this specimen to be most similar and closely related to Oviraptor than to the other oviraptorids known at that time.[10] Despite being discovered in 1995, the specimen IGM 100/1004 remained partially figured and largely undescribed for years until its formal referral to the taxon Citipati osmolskae in 2018 by Norell and team.[7]
The largest and most complete specimen of Citipati is represented by the holotype IGM 100/978, however, it was preliminarily described and figured in 2001 during the naming of the taxon and during that time, the specimen had not been completely prepared.[8] The skull anatomy of the specimen was later described by Clark and colleagues in 2002,[11] the furcula morphology in 2009 by Sterling J. Nesbitt with team,[12] and the caudal vertebrae by W. Scott Persons and colleagues in 2014 who noted the presence of a pygostyle.[13] Subsequent descriptions have been published in 2018 by Norell and team describing and illustrating some cervical vertebrae and uncinate processes,[7] and Amy M. Balanoff and colleagues describing the endocranium anatomy.[14] In 2003 Amy Davidson described the process in which the holotype was prepared,[15] later supplemental by Christina Bisulca and team in 2009 describing conservation treatments of broken bones.[16]
Zamyn Khondt oviraptorid
The Zamyn Khondt oviraptorid is a well-known oviraptorid represented by a single and rather complete specimen (IGM 100/42) collected from the Zamyn Khondt (also spelled as Dzamin Khond) locality of the
Clark with team have pointed out that this distinctive-looking, tall-crested oviraptorid has more features of the skull in common with Citipati than it does with Oviraptor. Though being different in the crest shape of the skull, the Zamyn Khondt oviraptorid is similar to Citipati in the shape of the narial region and premaxilla morphology. They considered this oviraptorid to belong to the genus, however, they could neither confirm nor disregard that this specimen represents a second species of Citipati.
Description
Citipati was a large-bodied oviraptorid, with the largest individuals being
Skull
Its skull was unusually short and highly
Classification
Citipati is often referred to the subfamily
Oviraptoridae |
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Paleobiology
Feeding mechanics
A 2022 study of the bite force of Citipati and comparisons with other oviraptorosaurs such as Incisivosaurus, Khaan, and Conchoraptor suggests that Citipati had a very strong bite force, scored between 349.3 N and 499.0 N. The moderate jaw gape seen in oviraptorosaurs is indicative of herbivory in the majority of the group, but it is clear they were likely feeding on much tougher vegetation than other herbivorous theropods in their environment, such as ornithomimosaurs and therizinosaurs were able to. The examinations suggest oviraptorosaurs may have been powerful-biting generalists or specialists that partook of niche partitioning both in body size and jaw function. Of the oviraptorids examined in this study, Citipati had one of the most powerful bites, but its biting mechanics were unique among the oviraptorosaurs investigated.[24]
Reproduction
The embryo-bearing egg was otherwise identical to other oviraptorid eggs in shell structure and was found in an isolated nest, again arranged in a circular pattern. Two skulls belonging to very young or embryonic
Although fossilized dinosaur eggs are rare, Citipati eggs and oviraptorid eggs in general, are relatively well known. Along with the two known nesting specimens, dozens of isolated oviraptorid nests have been uncovered in the
The two nesting specimens of Citipati are situated on top of egg clutches, with their limbs spread symmetrically on each side of the nest, front limbs covering the nest perimeter. This brooding posture is found today only in birds and supports a behavioral link between birds and theropod dinosaurs.
In 2014, W. Scott Persons and colleagues suggested that oviraptorosaurs were secondarily flightless and several of the traits in their tails may indicate a propensity for
Paleopathology
Clark and colleagues in 1999 during the description of "Big Mama" noted that the right ulna was badly broken but healed, leaving a prominent callus and possible elongated groove over the injury.[10] As the ulna features positive signs of healing, in 2019 Leas Hearn and team suggested that this individual managed to survive an injury that would have interfered with foraging for several weeks in order to lay and incubate its nest.[27]
In 2002 Clark with team reported a small notch preserved on the right jugal, just beneath the orbit, of the holotype skull of Citipati. This anomaly was likely produced by external damage, leaving a small injury.[11]
Paleoenvironment
Citipati is vastly known from the Ukhaa Tolgod locality of the
See also
References
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- ^ Wildford, J. N. (1995). "Fossil of Nesting Dinosaur Strengthens Link to Modern Birds". The New York Times (National ed.). p. 22.
- ^ a b Webster, D. (1996). "Dinosaurs of the Gobi: Unearthing a Fossil Trove". National Geographic. Vol. 190, no. 1. pp. 70–89.
- ^ Clark, J. M. (1995). "An egg thief exonerated". Natural History. 104 (6): 56.
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- ^ Davidson, A. (2003). "Preparation of a fossil dinosaur" (PDF). Objects Specialty Group Postprints. 10: 49−61. Archived from the original (PDF) on 12 November 2022. Retrieved 22 March 2022.
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- ^ Molina-Pérez & Larramendi (2016). Récords y curiosidades de los dinosaurios Terópodos y otros dinosauromorfos. Spain: Larousse. p. 272.
- ^ Paul, Gregory S. (2010). The Princeton Field Guide to Dinosaurs. New Jersey: Princeton University Press. p. 153.
- S2CID 6649123. Supplementary Information
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- ^ Varricchio, D.J. (2000). "Reproduction and Parenting," in Paul, G.S. (ed.). The Scientific American Book of Dinosaurs. New York: St. Martin's Press, pp. 279–293.
- ^ Hopp, T. P.; Orsen, M. J. (2004). "Dinosaur Brooding Behavior and the Origin of Flight Feathers" (PDF). In Currie, P. J.; Koppelhus, E. B.; Shugar, M. A.; Wright, J. L. (eds.). Feathered dragons: studies on the transition from dinosaurs to birds. Bloomington: Indiana University Press. pp. 234–250.
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- ^ Alicea, J.; Loewen, M. (2013). "New Minotaurasaurus material from the Djodokta Formation establishes new taxonomic and stratigraphic criteria for the taxon". Journal of Vertebrate Paleontology. Program and Abstracts: 76. Archived from the original on 1 November 2020. Retrieved 27 August 2022.
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External links
- Media related to Citipati at Wikimedia Commons
- Data related to Citipati at Wikispecies
- Interactive CT scan of the holotype Citipati skull at DigiMorph
- 3D model of the holotype Citipati skull at Sketchfab