Barun Goyot Formation

The Barun Goyot Formation (West Goyot Formation) is a geological formation dating to the Late Cretaceous Period. It is located within and is widely represented in the Gobi Desert Basin, in the Ömnögovi Province of Mongolia.

Barun Goyot Formation
Stratigraphic range: Maastrichtian
~72–71 Ma
TypeGeological formation
UnderliesNemegt Formation
OverliesDjadokhta Formation
Thicknessca. 110 m (360 ft)
Lithology
PrimarySandstone
Location
RegionGobi Desert
Country Mongolia

Description

It was previously known as the "Lower Nemegt Beds" occurring beneath the Nemegt Formation and above the Djadokhta Formation. It has been suggested that the Djadokhta and Barun Goyot Formations are lower and upper parts, respectively, of the same lithological unit and the boundary between the two does not exist. The stratotype of the Barun Goyot Formation is the Khulsan locality, east of Nemegt. At Nemegt, only the uppermost barungoyotian beds are visible. The Red Beds of Khermeen Tsav are also considered part of the Barun Goyot Formation. It is approximately 110 metres (360 ft) in thickness,[1] and was laid down roughly 72-71 million years ago. Given the new date for the start of the Maastrichtian (72.1 MYA) a basal Maastrichtian age seems probable. The Barun Goyot Formation preserves an environment of sand dunes, created from wind-eroded rocks (aeolian dunes).

Vertebrate paleofauna

Saurischians

Lizards

Genus Species Location Stratigraphic position Abundance Notes Images

Estesia

Estesia mongoliensis

An anguimorph

Ovoo

Ovoo gurvel

A Monitor lizard

Proplatynotia

Proplatynotia longirostrata

Gobiderma

Gobiderma pulchrum

A Monstersaur

Mammals

Ornithischians

Eggs

Oogenus Oospecies Location Material Notes

Styloolithus[10]

S. sabathi

Probably avian

Faveoloolithus[11]

F. ningxiaensis

Possibly sauropod eggs

See also

References

  1. ^ Gradzinski, R.; & Jerzykiewicz, T. (1974). Sedimentation of the Barun Goyot formation. Palaeontologica Polonica, 30, 111-146.
  2. ^ a b c d e f g h i j k l m n o p Nicholas R. Longrich; Philip J. Currie; Dong Zhi-Ming (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.
  3. ^ "Table 11.1," in Weishampel, et al. (2004). Page 213.
  4. ^ "Table 10.1," in Weishampel, et al. (2004). Page 199.
  5. ^ "Table 11.1," in Weishampel, et al. (2004). Page 211.
  6. ^ a b c Mortimer, M (2004). "Tyrannosauroidea". The Theropod Database. Archived from the original on 2013-09-29. Retrieved 2007-08-21.
  7. ^ "Table 22.1," in Weishampel, et al. (2004). Page 479.
  8. ^ "Table 17.1," in Weishampel, et al. (2004). Page 364.
  9. ^ a b Arbour, V. M., Currie, P. J. and Badamgarav, D. (2014), "The ankylosaurid dinosaurs of the Upper Cretaceous Baruungoyot and Nemegt formations of Mongolia". Zoological Journal of the Linnean Society, 172: 631–652. doi: 10.1111/zoj.12185
  10. ^ a b Varricchio, D.J. and D.E. Barta (2015). "Revisiting Sabath's "Larger Avian Eggs" from the Gobi Cretaceous" Acta Palaeontologica Polonica 60(1):11-25.
  11. ^ a b K. Mikhailov, K. Sabath, and S. Kurzanov. 1994. Eggs and nests from the Cretaceous of Mongolia. In K. Carpenter, K. F. Hirsch, and J. R. Horner (eds.), Dinosaur Eggs and Babies, Cambridge University Press, Cambridge 88-115.
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 85 to 70 million years ago.

Carusia

Carusia is an extinct genus of lizards from the Late Cretaceous of Mongolia. It is a close relative of the family Xenosauridae, which includes living knob-scaled lizards. Fossils of the type and only species Carusia intermedia come from the late-Campanian age Barun Goyot Formation and have been found in the Flaming Cliffs, Ukhaa Tolgod, and Kheerman Tsav fossil localities. Carusia was first described in 1985 under the name Carolina intermedia, but since the name Carolina was preoccupied by a genus of scarab beetles that had been named in 1880, it was renamed Carusia intermedia. Carusia had initially been known from fragmentary skull material, complicating efforts to determine its evolutionary relationships with other lizards; it had variously been described as an indeterminate scincomorph, a xenosaurid, or some other type of autarchoglossan lizard convergent with xenosaurids. However, the discovery of 35 complete skulls in the 1990s, three of which were described in a detailed 1998 monograph, revealed that Carusia was the sister taxon (closest relative) of Xenosauridae, compelling the authors of the monograph to create a new clade called Carusioidea to include both taxa.Like xenosaurids, Carusia has a skull roof covered in large rounded osteoderms (bony plates embedded in the skin). It also shares with xenosaurids closely spaced orbits (eye sockets) with fused frontal bones between them, and a connection between the jugal and squamosal bones. However, many other features of its skull set it apart from xenosaurids, including the lack of a lacrimal bone, the wideness of the palatine bone, and the small size and high number of teeth in its jaws.

Chulsanbaatar

Chulsanbaatar is a genus of mammal from the Cretaceous of Mongolia. It lived during the Mesozoic, also known as the "age of the dinosaurs." This small creature was a member of the extinct order of Multituberculata and is within the suborder Cimolodonta. The genus Chulsanbaatar was named by Kielan-Jaworowska Z. in 1974.

Fossil remains of the species Chulsanbaatar vulgaris have been found in strata dating to the Campanian (Upper Cretaceous) in the Red Beds of Hermiin Tsav (also known as Khermeen Tsav, part of the Barun Goyot Formation) in Mongolia.

This creature was a small multituberculate with a 2 cm skull. The jaw would fit on a fingertip. Remarkably, it has been possible to study the ear bones, which shows how well some of the fossils are preserved. Chulsanbaatar is now a resident of the Polish Academy of Science in Warsaw, Poland. (e.g. ZPAL MgM-1/84). There are a fair number of specimens in the collection, which doubtless accounts for the species name (vulgaris = common).

Estesia

Estesia (in honour of Richard Estes) is an extinct genus of Late Cretaceous helodermatoid lizard found in the Gobi Desert in Mongolia. It was discovered in June 1990 by a joint expedition made up of Mongolian and American palaeontologists, and described in 1992 by Mark Norell, Malcolm McKenna and Michael Novacek. This animal is of interest to palaeontologists, not only because it is close to the lineage of modern Gila monsters (Heloderma), but also because its dentition shows evidence that it was venomous.

The type species is E. mongoliensis, after Mongolia, where it was found.

Gobiceratops

Gobiceratops is a genus of ceratopsian dinosaur from the Upper Cretaceous of Mongolia. It is based on a skull that is 3.5 centimeters (1.4 inches) long, from the Khermin Tsav locality in the Barun Goyot Formation of southern Mongolia; the type individual was young. Gobiceratops is thought to have been related to Bagaceratops, and a member of Bagaceratopidae. It was described in 2008 by Alifanov. The type species is G. minutus.

Hollanda luceria

Hollanda is a genus of small ground birds known from fossils found in the Barun Goyot Formation of Mongolia. Found at Khermeen Tsav, it dates from the late Cretaceous period (Campanian stage), about 75 million years ago. Known only from partial hind limbs, Hollanda has long legs with an unusual configuration of the toes. These indicate that it was a fast-running ground bird, possibly similar to the modern Roadrunner. Its relationships are uncertain. Some studies have found that it was an relatively advanced bird, a member of the Ornithurae, related to birds like Ichthyornis. Other studies have recovered it as a member of the primitive family Songlingornithidae.

Hulsanpes

Hulsanpes is a genus of dromaeosaurid theropod dinosaur from Mongolia that lived during the Late Cretaceous.

Nemegt Basin

The Nemegt Basin is a geographical area in the northwestern Gobi Desert, in Ömnögovi Province, southern Mongolia. 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.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).

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).

Nessovbaatar

Nessovbaatar is a genus of extinct mammal from the Upper Cretaceous of Mongolia. It eked out its living in the company of Central Asian dinosaurs. This animal was a member of the extinct order Multituberculata within the suborder Cimolodonta and family Sloanbaataridae.

The genus Nessovbaatar ("Nesov's hero") was named by Kielan-Jaworowska Z. and Hurum J.H. in 1997 in honour of Russian paleontologist Dr. Nesov. The only known species is Nessovbaatar multicostatus (Kielan-Jaworowska & Hurum 1997), fossils of which were found in the Upper Cretaceous Barun Goyot Formation of Mongolia.

Parvicursor

Parvicursor (meaning "small runner") is a genus of tiny maniraptoran dinosaur with long slender legs for fast running. At only about 39 cm (c. 15 in) from snout to end of tail, and 162 grams (5.7 ounces) in weight, it is one of the smallest non-avian dinosaurs known from an adult specimen.

Like other members of the family Alvarezsauridae, the forelimbs of Parvicursor were short and stubby, with hands all but completely reduced to a single large claw, possibly useful for opening tough termite mounds or other types of digging. It is unlikely that the claw could have served much for defense, as it was short and not adapted for flexible movements — it is more likely it would do as the animal's name implies: cursor means runner.

Parvicursor is known from the late Campanian-age Barun Goyot Formation of Khulsan, Mongolia, dated at approximately 72 million years old. The type species, P. remotus, is only known from one incomplete specimen, mostly pelvis and hind legs. Close relatives include Shuvuuia and Mononykus, and together with these it is classified in the alvarezsaurid subfamily Parvicursorinae.

There may be a second, yet-unnamed, species of Parvicursor. Two specimens of tiny alvarezsaurids were described by Suzuki et al. in 2002. These authors considered the specimens to be juvenile Shuvuuia, which lived in the same formation. However, a study by Nick Longrich and Phil Currie in 2009 suggested that several characters of the skeleton, including fused wrist and pelvic bones, indicated that these specimens were in fact adults of a tiny alvarezsaurid species. A phylogenetic analysis found that they grouped together with Parvicursor, and the authors provisionally referred them to Parvicursor sp. pending further study.It has been suggested that Linhenykus may be a junior synonym of Parvicursor.

Presbyornithidae

Presbyornithidae is an extinct group of birds with a global distribution. They had evolved by the late Cretaceous period and became extinct during the early Miocene. Initially, they were believed to present a mix of characters shown by waterbirds, shorebirds and flamingos and were used to argue for an evolutionary relationship between these groups, but they are now generally accepted to be waterfowl closely related to modern ducks, geese, and screamers.They were generally long-legged, long-necked birds, standing around one meter high, with the body of a duck, feet similar to a wader but webbed, and a flat duck-like bill adapted for filter feeding. At least some species were social birds that lived in large flocks and nested in colonies, while others, like the Wilaru species, were terrestrial and solitary.Several genera have been classified as presbyornithids:

Presbyornis (type)

Headonornis (disputed)

Telmabates

Teviornis

Proherodius

Zhylgaia

WilaruThere are some other, undescribed, presbyornithid or possible presbyornithid remains, such as the partial right scapula BMNH PAL 4989, which was considered part of Headonornis hantoniensis, but cannot be positively refererred to a known taxon, or the Late Cretaceous remains from the Mongolian Barun Goyot Formation at Uday Sayr and the Nemegt Formation of Tsagaan Kushu.

Proplatynotia

Proplatynotia is an extinct genus of varanoid lizard from the Late Cretaceous of Mongolia. Fossils have been found in the Barun Goyot Formation, which is mid-Campanian in age. The type and only species, P. longirostratia, was named in 1984.

Quaesitosaurus

Quaesitosaurus (meaning "extraordinary lizard") is a genus of nemegtosaurid sauropod found by Kurzanov and Bannikov in 1983. The type species is Quaesitosaurus orientalis. It lived from 85 to 70 million years ago during the Late Cretaceous (Santonian to Campanian ages). Its fossils, consisting solely of a partial skull, were found in the Barun Goyot Formation near Shar Tsav, Mongolia. Long, low and horse-like with frontally located peg-teeth, it is similar enough to the skulls of Diplodocus and its kin to have prompted informed speculation that the missing body was formed like those of diplodocids.

It is possible that Nemegtosaurus, also known from only skull material, is a very close relative of Quaesitosaurus.

Styloolithus

Styloolithus is an oogenus of highly distinctive fossil egg from the Upper Cretaceous Djadokhta Formation and the Barun Goyot Formation in Mongolia.

Zaraapelta

Zaraapelta is an extinct genus of herbivorous ankylosaurid thyreophoran dinosaur from the Late Cretaceous of Mongolia. The type species is Zaraapelta nomadis, named and described by Arbour et alii in 2014. Zaraapelta is known from a single skull from the Barun Goyot Formation. It was found to be closest to Tarchia in the phylogenetic analysis within its description.

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