Fighting Dinosaurs

Last updated April 25, 2024

The Fighting Dinosaurs is a fossil specimen which was found in the Late Cretaceous Djadokhta Formation of Mongolia in 1971. It preserves a Protoceratops andrewsi and Velociraptor mongoliensis trapped in combat about 80 million years ago and provides direct evidence of predatory behavior in non-avian dinosaurs. The specimen has caused much debate as to how both animals came to be preserved together with relative completeness. Several hypotheses have been proposed, including a drowning scenario, burial by either dune collapse or sandstorm, or alternatively they were not buried simultaneously.

History of discovery

From 1963 to 1971, Polish-Mongolian paleontological expeditions were carried out in the Gobi Desert with the objective of fossil-finding. The expedition of 1971 visited several localities of the Djadokhta and Nemegt formations, discovering the lower beds of the latter. In that year on August 3, during the fieldwork of a team composed of paleontologists Tomasz Jerzykiewicz, Maciej Kuczyński, Teresa Maryańska, Edward Miranowski, Altangerel Perle and Wojciech Skarżyński, several fossils of Protoceratops and Velociraptor were found at the Tugriken Shire locality (Djadokhta Formation) including a block containing a pair of them. The individuals of this block were identified as a P. andrewsi struggling with a V. mongoliensis. Although the circumstances of their burial were unknown, their pose indicated that they died simultaneously in a death match.^[1]

The presence of the specimen on field was noted thanks to the overlapping skull fragments of the Protoceratops on the sediments, which eventually led to the excavation. It was soon nicknamed the Fighting Dinosaurs. The P. andrewsi individual is cataloged under the specimen number MPC-D 100/512 and the V. mongoliensis as MPC-D 100/25 (Mongolian Paleontological Center; originally GIN or GI SPS).^[2] In 2000 the American Museum of Natural History organized the traveling exhibit Fighting Dinosaurs: New Discoveries from Mongolia which was mainly focused on important Mongolian fossils with emphasis on the Fighting Dinosaurs, which is now regarded as a national treasure of Mongolia.^[3]

Interpretation

In 1974, Mongolian paleontologist Rinchen Barsbold suggested that the quicksand-like bottom of a lake could have kept them together or that both animals fell into a swamp-like waterbody, making the last moments of their fight underwater.^[4] In 1993, Polish paleontologist Halszka Osmólska proposed that during the death struggle a large dune may have collapsed, simultaneously burying both Protoceratops and Velociraptor. Alternatively, the Velociraptor may have been scavenging an already dead Protoceratops and then got buried and eventually killed by an unknown event.^[5]

In 1995, David M. Unwin and colleagues argued that scavenging was unlikely as there were numerous indications of a simultaneous death. The Protoceratops has a semi-erect stance and its skull is horizontally oriented, which would have not been possible if the animal was already dead. The Velociraptor has its right hand trapped within the jaws of the Protoceratops and the left one scratching the Protoceratops skull. As it lies on the floor with its feet directed to the prey's abdomen and throat areas, it is unlikely that the Velociraptor was scavenging. Unwin and colleagues also examined the sediments surrounding the specimen and concluded that the pair was buried alive by a sandstorm or sand-bearing event. They interpreted the final interaction with the Protoceratops being grasped and dispatched with kicks delivered by the low-lying Velociraptor. Finally, they suggested that populations of Velociraptor could have been aware of crouching behaviors in Protoceratops during high-energy sandstorms and used it for successful hunts.^[6]

In 1998, Kenneth Carpenter suggested another scenario in which the multiple wounds delivered by the Velociraptor on the Protoceratops throat had the latter animal bleeding to death. As a last effort, the Protoceratops bit the right hand of the predator and trapped it under its own weight, causing the death and eventual desiccation of the Velociraptor. The missing limbs of the Protoceratops were later torn off by scavengers. Finally, both animals were buried by sandy sediments. Given that the Velociraptor is relatively complete, Carpenter suggested that it may have been completely or partially buried by sand. He concluded that the Fighting Dinosaurs is among the specimens that provide direct evidence for non-avian theropods as active predators and not strict scavengers.^[2]

In 2016 Barsbold reported several anomalies within the Protoceratops individual: both coracoids have small bone fragments indicative of a breaking of the pectoral girdle, and the right forelimb and scapulocoracoid are torn off to the left and backwards, relative to its torso. He concluded that the prominent displacement of pectoral elements and right forelimb was caused by an external force that tried to tear them out. Barsbold suggested that scavengers were the most likely authors of these anomalies since the Protoceratops is missing other body elements and this event likely occurred after the death of both animals or during a point where movement was not possible. Because Protoceratops is considered to have lived in herds, another hypothesis is that members of a herd tried to pull out the already buried Protoceratops, causing the dislocation of its limbs. However, Barsbold pointed out that there are no related traces to support this latter interpretation. Lastly, he restored the course of the fight with the Protoceratops powerslamming the Velociraptor, which used its raptorial sickle claws to damage the throat and belly regions and its hand claws to grasp the herbivore's head. Prior to their burial, the fight ended up on the ground with the Velociraptor lying on its back under the Protoceratops. After the burial event, either a Protoceratops herd or scavengers tore off the buried Protoceratops to the left and backwards, slightly separating the Protoceratops and the Velociraptor.^[7]

Related Research Articles

Velociraptor is a genus of small dromaeosaurid dinosaurs that lived in Asia during the Late Cretaceous epoch, about 75 million to 71 million years ago. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis, named and described in 1924. Fossils of this species have been discovered in the Djadochta Formation, Mongolia. A second species, V. osmolskae, was named in 2008 for skull material from the Bayan Mandahu Formation, China.

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>Protoceratops</i> Genus of reptiles (fossil)

Protoceratops is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 75 to 71 million years ago. The genus Protoceratops includes two species: P. andrewsi and the larger P. hellenikorhinus. The former was described in 1923 with fossils from the Mongolian Djadokhta Formation, and the latter in 2001 with fossils from the Chinese Bayan Mandahu Formation. Protoceratops was initially believed to be an ancestor of ankylosaurians and larger ceratopsians, such as Triceratops and relatives, until the discoveries of other protoceratopsids. Populations of P. andrewsi may have evolved into Bagaceratops through anagenesis.

Enigmosaurus is a genus of therizinosauroid that lived in Asia during the Late Cretaceous period. It was a medium-sized, ground-dwelling, bipedal herbivore that represents the third therizinosaur taxon from the Bayan Shireh Formation, although it is known from the lower part. The genus is monotypic, including only the type species E. mongoliensis, known from a well preserved pelvis and other tentative body remains.

Saurornithoides is a genus of troodontid maniraptoran dinosaur, which lived during the Late Cretaceous period. These creatures were predators, which could run fast on their hind legs and had excellent sight and hearing. The name is derived from the Greek stems saur~ (lizard), ornith~ (bird) and eides (form), referring to its bird-like skull.

Adasaurus is a genus of dromaeosaurid dinosaur that lived in Asia during the Late Cretaceous period about 70 million years ago. The genus is known from two partial specimens found in the Nemegt Formation of Mongolia that were partially described in 1983 by the paleontologist Rinchen Barsbold.

Cretaceous Mongolia is one of the strangest and best preserved of all Mesozoic ecosystems. The shifting sand of what was, even then, the Gobi Desert have ensured that fossils of the animals that lived there can be found in exactly the position in which they were buried, with most of the bones together. The most notable fossil is the very well preserved remains of a Velociraptor, locked in combat with a Protoceratops, a small ceratopsian.

Protoceratopsidae is a family of basal (primitive) ceratopsians from the Late Cretaceous period. Although ceratopsians have been found all over the world, protoceratopsids are only definitively known from Cretaceous strata in Asia, with most specimens found in China and Mongolia. As ceratopsians, protoceratopsids were herbivorous, with constantly replacing tooth batteries made for slicing through plants and a hooked beak for grabbing them. Protoceratopsids were small ceratopsians around 1-2.5 m in length. Their bony frill and horns were much smaller than more derived members of Ceratopsia, such as ceratopsids.

Bagaceratops is a genus of small protoceratopsid dinosaurs that lived in Asia during the Late Cretaceous, around 72 to 71 million years ago. Bagaceratops remains have been reported from the Barun Goyot Formation and Bayan Mandahu Formation. One specimen may argue the possible presence of Bagaceratops in the Djadochta Formation.

The Djadochta Formation is a highly fossiliferous geological formation situated in Central Asia, Gobi Desert, dating from the Late Cretaceous period, about 75 million to 71 million years ago. The type locality is the Bayn Dzak locality, famously known as the Flaming Cliffs. Reptile and mammal remains are among the fossils recovered from the formation.

Tsaagan is a genus of dromaeosaurid dinosaur from the Djadokhta Formation of the Late Cretaceous of Mongolia.

<span class="mw-page-title-main">Mahakala omnogovae</span> Extinct species of dinosaur

Mahakala is a genus of halszkaraptorine theropod dinosaur from the Campanian-age Upper Cretaceous Djadokhta Formation of Ömnögovi, Mongolia. It is based on a partial skeleton found in the Gobi Desert. Mahakala was a small dromaeosaurid, and its skeleton shows features that are also found in early troodontids and avialans. Despite its late appearance, it is among the most basal dromaeosaurids. Its small size, and the small size of other basal deinonychosaurians, suggests that small size appeared before flight capability in birds. The genus is named for Mahakala, one of eight protector deities (dharmapalas) in Tibetan Buddhism.

Minotaurasaurus is a monospecific genus of ankylosaurid dinosaur that lived in Mongolia during the Late Cretaceous in what is now the Djadochta Formation. The type and only species, Minotaurasaurus ramachandrani, is known from two skulls, a cervical vertebra and a cervical half ring. It was named and described in 2009 by Clifford Miles and Clark Miles. The first fossils of Minotaurasaurus were illegally exported out of Mongolia.It has been suggested to be a synonym of Tarchia but more recent publications consider it as a distinct genus.

The Bayan Mandahu Formation is a geological unit of "redbeds" located near the village of Bayan Mandahu in Inner Mongolia and China and dates from the late Cretaceous Period. Laid down in the Campanian, it is dated somewhat uncertainly to between 75 and 71 mya.

<i>Elongatoolithus</i> Fossil dinosaur eggs

Elongatoolithus is an oogenus of dinosaur eggs found in the Late Cretaceous formations of China and Mongolia. Like other elongatoolithids, they were laid by small theropods, and were cared for and incubated by their parents until hatching. They are often found in nests arranged in multiple layers of concentric rings. As its name suggests, Elongatoolithus was a highly elongated form of egg. It is historically significant for being among the first fossil eggs given a parataxonomic name.

Egg taphonomy is the study of the decomposition and fossilization of eggs. The processes of egg taphonomy begin when the egg either hatches or dies. Eggshell fragments are robust and can often travel great distances before burial. More complete egg specimens gradually begin to fill with sediment, which hardens as minerals precipitate out of water percolating through pores or cracks in the shell. Throughout the fossilization process the calcium carbonate composing the eggshell generally remains unchanged, allowing scientists to study its original structure. However, egg fossils buried under sediments at great depth can be subjected to heat, pressure and chemical processes that can alter the structure of its shell through a process called diagenesis.

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Halszkaraptorinae is a basal ("primitive") subfamily of Dromaeosauridae that includes the enigmatic genera Halszkaraptor, Natovenator, Mahakala, and Hulsanpes. Halszkaraptorines are definitively known only from Late Cretaceous strata in Asia, specifically in Mongolia. Following the recent discovery of Natovenator, a member of the subfamily, the group is believed to have a semiaquatic lifestyle.

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References

↑ Kielan-Jaworowska, Z.; Barsbold, R. (1972). "Narrative of the Polish-Mongolian Palaeontological Expeditions, 1967-1971" (PDF). Palaeontologia Polonica. 27: 1−12.
1 2 Carpenter, K. (1998). "Evidence of predatory behavior by carnivorous dinosaurs" (PDF). Gaia. 15: 135−144.
↑ "Fighting Dinos". AMNH. American Museum of National History. 2000.
↑ Barsbold, R. (1974). "Поединок динозавров" [Dueling dinosaurs]. Priroda (in Russian). 2: 81−83.
↑ Osmólska, H. (1993). "Were the Mongolian Fighting Dinosaurs really fighting?". Rev. Paleobiol. 7: 161−162.
↑ Unwin, D. M.; Perle, A.; Trueman, C. (1995). "Protoceratops and Velociraptor preserved in association: Evidence from predatory behavior in predatory dinosaurs?". Journal of Vertebrate Paleontology. 15 (supp. 003): 57A. doi:10.1080/02724634.1995.10011277.
↑ Barsbold, R. (2016). "The Fighting Dinosaurs: The position of their bodies before and after death". Paleontological Journal. 50 (12): 1412−1417. Bibcode:2016PalJ...50.1412B. doi:10.1134/S0031030116120042. S2CID 90811750.

External links

Media related to Fighting Dinosaurs at Wikimedia Commons
Reconstructed Fighting Dinosaurs at ArtStation
3D model of the Fighting Dinosaurs specimen at Sketchfab

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[1] Kielan-Jaworowska, Z.; Barsbold, R. (1972). "Narrative of the Polish-Mongolian Palaeontological Expeditions, 1967-1971" (PDF). Palaeontologia Polonica. 27: 1−12.

[Carpenter1998-2] 1 2 Carpenter, K. (1998). "Evidence of predatory behavior by carnivorous dinosaurs" (PDF). Gaia. 15: 135−144.

[3] "Fighting Dinos". AMNH. American Museum of National History. 2000.

[4] Barsbold, R. (1974). "Поединок динозавров" [Dueling dinosaurs]. Priroda (in Russian). 2: 81−83.

[5] Osmólska, H. (1993). "Were the Mongolian Fighting Dinosaurs really fighting?". Rev. Paleobiol. 7: 161−162.

[6] Unwin, D. M.; Perle, A.; Trueman, C. (1995). "Protoceratops and Velociraptor preserved in association: Evidence from predatory behavior in predatory dinosaurs?". Journal of Vertebrate Paleontology. 15 (supp. 003): 57A. doi:10.1080/02724634.1995.10011277.

[7] Barsbold, R. (2016). "The Fighting Dinosaurs: The position of their bodies before and after death". Paleontological Journal. 50 (12): 1412−1417. Bibcode:2016PalJ...50.1412B. doi:10.1134/S0031030116120042. S2CID 90811750.

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