Nemegt Basin

The Nemegt Basin is a geographical area in the northwestern Gobi Desert, in Ömnögovi Province, southern Mongolia.[1] It is known locally as the "Valley of the Dragons", since it is a source of many fossil finds, including dinosaurs, dinosaur eggs, and trace fossils.[2]

The main geological formations in the area are the Nemegt Formation, Barun Goyot Formation, and Djadochta Formation, in order of age, from youngest (most superficial) to oldest (deepest).[3][4]

Map mn umnugobi aimag
Map of Mongolia, showing Ömnögovi Province.

References

  1. ^ Klasfeld, Adam (September 10, 2012). "Judge Puts Kibosh on Dinosaur Forfeiture". Courthouse News Service. Retrieved 23 January 2014.
  2. ^ Benton, Michael J.; Shishkin, Mikhail A.; Unwin, David M.; Evgenii N. Kurochkin (2003-12-04). The Age of Dinosaurs in Russia and Mongolia. Cambridge University Press. pp. 229–231. ISBN 9780521545822. Retrieved 23 January 2014.
  3. ^ Currie, Philip J.; Padian, Kevin (1997-10-06). Encyclopedia of Dinosaurs. Academic Press. p. 41. ISBN 9780080494746. Retrieved 23 January 2014.
  4. ^ Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (1990-01-01). The Dinosauria. University of California Press. p. 403. ISBN 9780520067264. Retrieved 23 January 2014.
Avimimus

Avimimus ( AY-vi-MY-məs), meaning "bird mimic" (Latin avis = bird + mimus = mimic), was a genus of oviraptorosaurian theropod dinosaur, named for its bird-like characteristics, that lived in the late Cretaceous in what is now Mongolia, around 70 million years ago.

Bone bed

A bone bed is any geological stratum or deposit that contains bones of whatever kind. Inevitably, such deposits are sedimentary in nature. Not a formal term, it tends to be used more to describe especially dense collections such as Lagerstätte. It is also applied to brecciated and stalagmitic deposits on the floor of caves, which frequently contain osseous remains.In a more restricted sense, the term is used to describe certain thin layers of bony fragments, which occur in well-defined geological strata. One of the best-known of these is the Ludlow Bone Bed, which is found at the base of the Downton Sandstone in the Upper Ludlow series. At Ludlow (England) itself, two such beds are actually known, separated by about 14 ft (4.3 m). of strata. Although quite thin, the Ludlow Bone Bed can be followed from that town into Gloucestershire, for a distance of 45 miles (72 km). It is almost completely made up of fragments of spines, teeth and scales of ganoid fish. Another well-known bed, formerly known as the Bristol or Lias Bone Bed, exists in the form of several thin layers of micaceous sandstone, with the remains of fish and saurians, which occur in the Rhaetic Black Paper Shales that lie above the Keuper marls, in the south-west of England. It is noteworthy that a similar bone bed has been traced on the same geological horizon in Brunswick, Hanover (Germany), in Franconia and in Tübingen (Germany). A bone bed has also been observed at the base of the Carboniferous limestone series, in certain parts of the south-west of England.Bone beds are also recorded in North America, South America, Mongolia and China. Terrestrial bonebed examples are: the Triassic Metoposaurus bone bed from Portugal, the Mapusaurus bone bed at Cañadón del Gato, in Argentina, the Allosaurus-dominated Cleveland-Lloyd Dinosaur Quarry of Utah, the Dinosaur National Monument on the boundary of Utah and Colorado, an Albertosaurus bone bed from Alberta, a Daspletosaurus bone bed from Montana, the Cenozoic John Day Fossil Beds of Oregon and the Nemegt Basin in the Gobi Desert region of Mongolia. Bentiaba, Angola, is an example of a marine bonebed with numerous mosasaurs and plesiosaurs.

Borogovia

Borogovia is a troodontid theropod dinosaur genus which lived during the Late Cretaceous Period, in what is now Mongolia.

In 1971, a Polish-Mongolian expedition discovered the remains of a small theropod at the Altan Ula IV site, in the Nemegt Basin of Ömnögovĭ province. In 1982, the find was reported by Halszka Osmólska and considered by her to be a possible specimen of Saurornithoides. Later she concluded that it represented a species new to science.

In 1987, Osmólska named and described the type species Borogovia gracilicrus. The generic name is derived from the fantasy creatures known as 'borogoves' in the Lewis Carroll poem "Jabberwocky", in his Alice's Adventures in Wonderland. The specific name is a combination of Latin gracilis, "lightly built", and crus, "shin", in reference to the elegant build of the lower leg.The holotype specimen, ZPAL MgD-I/174, was found in the Nemegt Formation, dating from the early Maastrichtian. It consists of two lower legs of a single individual, including fragments of both tibiotarsi, the undersides of both metatarsi and the second, third and fourth toes of each foot.The tibiotarsi have an estimated length of twenty-eight centimetres. Borogovia is about two meters (6 feet) long, weighing some twenty kilograms (forty-five pounds). The tibiotarsus is very elongated. The third toe is narrow. The second phalanx of the second toe is short. The claw of the second toe is short and relatively flat. Osmólska claimed that the second toe could not be hyperextended, and suggested that it had regained a weight-bearing function, compensating for the weakness of the third toe.Borogovia was assigned by Osmólska to the Troodontidae in 1987.

Breviceratops

Breviceratops (meaning "short horn face") was a herbivorous ceratopsian dinosaur from the Late Cretaceous of Mongolia.

Gallimimus

Gallimimus ( GAL-i-MY-məs) is a genus of theropod dinosaur that lived in what is now Mongolia during the Late Cretaceous period, about 70 million years ago (mya). Gallimimus is the largest known ornithomimid; adults were about 6 metres (20 ft) long, 1.9 metres (6 ft 3 in) tall at the hip and weighed about 440 kilograms (970 lb). As evidenced by its relative Ornithomimus, it would have had feathers. The head was small and light with large eyes that faced to the sides. The snout was long compared to other ornithomimids, although it was broader and more rounded at the tip than in other species. Gallimimus was toothless with a keratinous (horny) beak, and had a delicate lower jaw. Many of the vertebrae had openings that indicate they were pneumatic (air-filled). The neck was proportionally long in relation to the trunk. The hands were proportionally the shortest of any ornithomimosaur and each had three digits with curved claws. The forelimbs were weak while the hindlimbs were proportionally long.

Several fossils in various stages of growth were discovered by Polish-Mongolian expeditions in the Gobi Desert of Mongolia during the 1960s; a large skeleton discovered in this region was made the holotype specimen of the new genus and species Gallimimus bullatus in 1972. The generic name means "chicken mimic", referring to the similarities between its neck vertebrae and those of the Galliformes. The specific name is derived from bulla, a gold capsule worn by Roman youth, in reference to a bulbous structure at the base of the skull of Gallimimus. At the time it was named, the fossils of Gallimimus represented the most complete and best preserved ornithomimid material yet discovered, and the genus remains one of the best known members of the group. The family Ornithomimidae is part of the group Ornithomimosauria, the "ostrich dinosaurs". Anserimimus, also from Mongolia, is thought to have been the closest relative of Gallimimus.

As an ornithomimid, Gallimimus would have been a fleet (or cursorial) animal, using its speed to escape predators; its speed has been estimated at 42-56 km/h (29-34 mph). It may have had good vision and intelligence comparable to ratite birds. Gallimimus may have lived in groups, based on the discovery of several specimens preserved in a bone bed. Various theories have been proposed regarding the diet of Gallimimus and other ornithomimids. The highly mobile neck may have helped locate small prey on the ground, but it may also have been an opportunistic omnivore. It has also been suggested that it used small columnar structures in its beak for filter-feeding in water, though these structures may instead have been ridges used for feeding on tough plant material, indicative of a herbivorous diet. Gallimimus is the most commonly found ornithomimosaur in the Nemegt Formation, where it lived alongside its relatives Anserimimus and Deinocheirus. Gallimimus was featured in the movie Jurassic Park, in a scene that was important to the history of special effects, and in shaping the common conception of dinosaurs as bird-like animals.

Gobipteryx

Gobipteryx (from Gobi [referring to the Gobi Desert where it was first discovered], Greek pteron “wing”) is a genus of prehistoric bird from the Campanian Age of the Late Cretaceous Period. It is not known to have any direct descendants. Like the rest of the enantiornithes clade, Gobipteryx is thought to have gone extinct near the end of the Cretaceous.

Graciliceratops

Graciliceratops (meaning 'graceful horned face') is a small ceratopsian dinosaur originally described by Teresa Maryańska and Halszka Osmólska in 1975 and referred to Microceratops gobiensis. It was later redescribed as a new genus and species by Paul Sereno in 2000. It is known from the Late Cretaceous period and its fossils were found in Mongolia. Only a partial skeleton has been found. The type (and only known) species is Graciliceratops mongoliensis.

Graciliceratops is known from Shireegiin Gashuun Formation in Mongolia's Gobi Desert, north of the Nemegt Basin. The Shireegiin Gashuun locality is thought to be older than the Djadokhta localities that produced Protoceratops, and is probably early Late Cretaceous in age. The relationships of the genus are unclear, however the frill has large fenestrae bounded by very slender struts. This structure is very similar to that of the later Protoceratops.The skull of the animal measures an estimated twenty centimetres, and the whole animal would have been about the size of a cat. However, the arches and bodies of the vertebrae are not fused, which suggests that the animal was not fully grown when it died. The adult may have approached Protoceratops in size, which grew to around two meters.Like other ceratopsians, Graciliceratops would have been an herbivore, using its powerful beak and shearing teeth to process tough plant matter. Little is known about the flora of the ancient Gobi Desert, and so it is unclear what it would have eaten.

Heyuannia

Heyuannia ("from Heyuan") is a genus of oviraptorid dinosaur that lived during the Late Cretaceous Period in China. It was the first oviraptorid found in that country; most others were found in neighbouring Mongolia. Two species are known: H. huangi, named by Lü Junchang in 2002; and H. yanshini, originally named as a separate genus Ingenia by Rinchen Barsbold in 1981 (and renamed to Ajancingenia in 2013 due to the preoccupation of Ingenia).

Nemegt

Nemegt can refer to:

Nemegt: the settlement of that name, in the Ömnögovi Province of Mongolia.

Nemegt Basin: the topographical feature in the Gobi Desert region of Mongolia.

Nemegt Formation: the geological rock formation, taking its name from the region.

Nemegt Formation

The Nemegt Formation (or Nemegtskaya Svita) is a geological formation in the Gobi Desert of Mongolia, dating to the Late Cretaceous. It overlies and sometimes interfingers with the Barun Goyot Formation. Interfingering has been noted at the stratotype (Red Walls) and Khermeen Tsav. It consists of river channel sediments and contains fossils of fish, turtles, crocodilians, and a diverse fauna of dinosaurs, including birds. The climate associated with it was wetter than when preceding formations were deposited; there seems to have existed at least some degree of forest cover. Fossilized trunks have been also found.

There has been no absolute dating of the Nemegt Formation. It is, however, almost certainly early Maastrichtian c 71-70 Ma. Gradzinski and others considered a Campanian age possible but more recent research indicates otherwise. A Campanian age no longer seems credible, because the Alagteegian (or lower Djadokhtan, at the locality "Chuluut Uul") has been radiometrically dated at about 73.5 Ma or even younger (a more recent K/Ar date is 71.6 +/- 1.6 Ma). The c 73.5 (or perhaps 72) Ma Alagteegian is separated from the Nemegt by the "classic" Djadokhtan (e.g. Bayan Dzag), later Djadohktan (represented by Ukhaa Tolgod) and Barungoyotian (Khulsan). All these intervening horizons almost certainly represent more than the 1.5 million years between the dated Alagteegian level and the onset of Maastrichtian time (72.1 million Ma according to current dating). Ergo the Nemegt is entirely Maastrichtian. See also Shuvalov, Sochava and Martinsson The Age of Dinosaurs in Russia and Mongolia. The presence of Saurolophus further supports an early Maastrichtian age as the same genus occurs in the early Maastrichtian Horseshoe Canyon formation.

Nemegtbaatar

Nemegtbaatar is a genus of mammal from the Upper Cretaceous Period of what is now Mongolia. It existed in the company of much larger dinosaurs, found together in the Nemegt Basin. This creature was a member of the extinct order Multituberculata. It is within the suborder Cimolodonta and is a member of the superfamily Djadochtatherioidea. It was a hopping, gerboa-like species.

The genus Nemegtbaatar (Kielan-Jaworowska Z., 1974) is known by the species Nemegtbaatar gobiensis found in the Santonian to Campanian (Upper Cretaceous) Barun Goyot Formation of Mongolia. "Compared to all extant mammals, the braincase in Nemegtbaatar and Chulsanbaatar is primitive." (Hurum, 1998). "All extant mammals" includes monotremes, such as the duck-billed platypus, despite its residual egg-laying habit.

Nemegtbaatar was a relatively large member of Djadochtatherioidea, with a skull length of up to 4.5 centimetres (1.8 in). At least one specimen is in the Institute of Paleobiology collection of the Polish Academy of Science at Warsaw, (ZPAL MgM-1/76).

Nemegtomaia

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.

Nemegtomaia is estimated to have been around 2 m (7 ft) in length, and to have weighed 40 kg (85 lb). As an oviraptorosaur, it would have been feathered. It had a deep, narrow, and short skull, with an arched crest. It was toothless, had a short snout with a parrot-like beak, and a pair of tooth-like projections on its palate. It had three fingers; the first was largest and bore a strong claw. Nemegtomaia is classified as a member of the oviraptorid subfamily Ingeniinae, and it the only known member of this group with a cranial crest. Though Nemegtomaia has been used to suggest that oviraptorosaurs were flightless birds, the clade is generally considered a group of non-avian dinosaurs.

The nesting Nemegtomaia specimen was placed on top of what was probably a ring of eggs, with its arms folded across them. None of the eggs are complete, but they are estimated to have been 5 to 6 cm (2 to 2.3 in) wide and 14 to 16 cm (5 to 6 in) long when intact. The specimen was found in a stratigraphic area that indicates Nemegtomaia preferred nesting near streams that would provide soft, sandy substrate and food. Nemegtomaia may have protected its eggs by covering them with its tail and wing feathers. The skeleton of the nesting specimen has damage that indicates it was scavenged by skin beetles. The diet of oviraptorids is uncertain, but their skulls are most similar to other animals that are known or thought to have been herbivorous. Nemegtomaia is known from the Nemegt and Baruungoyot Formations, which are thought to represent humid and arid environments that coexisted in the same area,

Nemegtosaurus

Nemegtosaurus (meaning 'Reptile from the Nemegt') was a sauropod dinosaur from Late Cretaceous Period of what is now Mongolia. Nemegtosaurus was named after the Nemegt Basin in the Gobi Desert, where the remains — a single skull — were found. The skull resembles diplodocoids in being long and low, with pencil-shaped teeth. However, recent work has shown that Nemegtosaurus is in fact a titanosaur, closely related to animals such as Saltasaurus, Alamosaurus and Rapetosaurus.

Opisthocoelicaudia

Opisthocoelicaudia is a genus of sauropod dinosaur of the Late Cretaceous Period discovered in the Gobi Desert of Mongolia. The type species is Opisthocoelicaudia skarzynskii. A well-preserved skeleton lacking only the head and neck was unearthed in 1965 by Polish and Mongolian scientists, making Opisthocoelicaudia one of the best known sauropods from the Late Cretaceous. Tooth marks on this skeleton indicate that large carnivorous dinosaurs had fed on the carcass and possibly had carried away the now-missing parts. To date, only two additional, much less complete specimens are known, including a part of a shoulder and a fragmentary tail. A relatively small sauropod, Opisthocoelicaudia measured about 11.4 metres (37 ft) in length. Like other sauropods, it would have been characterised by a small head sitting on a very long neck and a barrel shaped trunk carried by four column-like legs. The name Opisthocoelicaudia means "posterior cavity tail", alluding to the unusual, opisthocoel condition of the anterior tail vertebrae that were concave on their posterior sides. This and other skeletal features lead researchers to propose that Opisthocoelicaudia was able to rear on its hindlegs.

Named and described by Polish paleontologist Maria Magdalena Borsuk-Białynicka in 1977, Opisthocoelicaudia was first thought to be a new member of the Camarasauridae, but is currently considered a derived member of the Titanosauria. Its exact relationships within Titanosauria are contentious, but it may have been close to the North American Alamosaurus. All Opisthocoelicaudia fossils stem from the Nemegt Formation. Despite being rich in dinosaur fossils, the only other sauropod from this rock unit is Nemegtosaurus, which is known from a single skull. Since the skull of Opisthocoelicaudia remains unknown, several researchers have suggested that Nemegtosaurus and Opisthocoelicaudia may represent the same species. Sauropod footprints from the Nemegt Formation, which include skin impressions, can probably be referred to either Nemegtosaurus or Opisthocoelicaudia as these are the only known sauropods from this formation.

Protoceratopsidae

Protoceratopsidae is a family within the group Ceratopsia. The name Protoceratopsidae is derived from Greek for "first horned face". Protoceratopsids have so far been found in the Late Cretaceous, dating to between about 99.6 and 70.6 million years ago. Although Ceratopsians have been found all over the world, protoceratopsids are only known from Asia with most specimens found in China and the Nemegt Basin in 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 relatively small, between 1-2.5 m in length from head to tail. Their bony frill and horns were much smaller than more derived members of Ceratopsia. Protoceratopsids were likely slow runners and tended to move at a walk or a trot. Their legs may have been straight, creating an upright posture, but there are some theories that they were splayed out to the side, contributing to their slowness. There is evidence that Protoceratops formed groups. Specimens of juveniles and young adults are often found in groups, although adults tend to be solitary. The nature of these groups is not completely known, though herds of young likely formed for protection from predators, and adults are believed to have come together for communal nesting.

Rinchen Barsbold

Dr. Rinchen Barsbold (Mongolian: Ринченгийн Барсболд, Rinchyengiin Barsbold, born December 21, 1935 in Ulaanbaatar) is a Mongolian paleontologist and geologist. He works with the Institute of Geology, at Ulaanbaatar, Mongolia. He is recognized around the world as a leader in vertebrate paleontology and Mesozoic stratigraphy.

Barsbold has been instrumental in the discovery and recovery of one of the largest dinosaur collections in the world. His work has projected Mongolian paleontology into world prominence and helped to form a more modern understanding of the later stages of dinosaur evolution in Eurasia.

Barsbold has had considerable influence on dinosaur paleontology in the Communist world. Barsbold's scientific work has made him a leading authority on theropods of the Gobi Desert, starting with his doctoral dissertation on these dinosaurs. As early as 1983, he noted that in different lineages of theropods, many features previously only known from birds had evolved in various combinations (Barsbold 1983). He postulated that as a result of this "ornithization", one or several lineages of theropods that happened to acquire the proper combination of such traits went on to evolve into actual birds.

Since the identification of a number of feathered dinosaurs beginning in the late 1990s, Barsbold's ideas are more fully appreciated. When he initially published his conclusions - a list of generally rather obscure anatomical features - in 1983, there was little exchange between the Mongolian scientific community and that of Western countries. Moreover, Barsbold's early papers were usually published in Russian, in which few Western scientists are fluent. In addition, Evgeny Kurochkin - probably the leading specialist on bird paleontology in the then-Communist world - was critical of the theropod-bird link, working with and teaching mostly Cenozoic bird paleontology. Therefore, Barsbold's theories initially had more impact among "dinosaur" paleontologists in Mongolia, the USSR, and allied countries.

Tarchia

Tarchia (meaning "brainy one") is a genus of herbivorous ankylosaurid dinosaur from the late Cretaceous of Mongolia.

Teresa Maryańska

Teresa Maryańska is a Polish paleontologist who has specialized in Mongolian dinosaurs, particularly pachycephalosaurians and ankylosaurians. Peter Dodson (1998 p. 9) claims that in 1974 Maryanska together with Halszka Osmólska were among the first "women to describe new kinds of dinosaurs". She is considered not only as one of Poland's but also one of the world's leading experts on dinosaurs.A member of the 1964, 1965, 1970, and 1971 Polish–Mongolian expeditions to the Gobi Desert, she has described many finds from these rocks, often with Halszka Osmólska. Among the dinosaurs she has described are:

Saichania and Tarchia (1977)

with Osmólska, Homalocephale, Prenocephale, and Tylocephale (and Pachycephalosauria) (1974), Bagaceratops (1975), and Barsboldia (1981)

and with Osmόlska and Altangerel Perle, Goyocephale (1982).Alan Feduccia notes that Maryanska and her colleagues (Osmólska and Wolsan) produced in 2002 the "most impressive analysis of the oviraptorosaurs".Amongst her many publications are contributions to three chapters of the 2nd edition of the highly respected The Dinosauria: the chapters on the Therizinosauroidea, the Ankylosauria and on the Pachycephalosauria.As of 2004, she was affiliated with the Muzeum Ziemi of the Polska Akademia Nauk. She was assistant director of Muzeum Ziemi.

Ukhaatherium

Ukhaatherium is a now extinct species of mammal that lived during the upper Cretaceous about 84 to 72 million years ago in today's East Asia. It is known above all from Ukhaa Tolgod, where it alone is occupied by eight individuals, six of them completely. In general, Ukhaatherium weighing about 32 g was quite small and resembled today's insect eaters. In addition, there were still some original skeletal features.

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