FANDOM


The Nemegt Formation (or Nemegtskaya Svita) is a geological formation dating from the Late Cretaceous sedimentary from the Gobi Desert of Mongolia. It overlies and sometimes forms folds with the Barun Goyot Formation.[citation needed] It consists of river channel sediments and contains fossils of fish, turtles, crocodilians, birds and a diverse fauna of dinosaurs. 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.

The absolute age of the Nemegt Formation is unknown but it is thought to be early Maastrichtian to possibly late Campanian in age, very roughly 70 million years old.

DescriptionEdit

The Nemegt Formation (the upper beds) are composed of shales and sandstones that were deposited by ancient lakes, streams, and flood plains. The Altan Ula locality, was described by Michael Novacek (1996) as "a canyon carved out of a very rich series of sedimentary rocks" with "steep cliffs and narrow washes". The presence of petrified wood, and the remains of Araucariaceae conifers indicate that the forests of the Nemegt were thickly wooded, with a high canopy formed by tall conifer trees. When examined, the rock facies of this formation suggest the presence of stream and river channels, mudflats, and shallow lakes. Sediments also indicate that there existed a rich habitat, offering diverse food in abundant amounts that could sustain massive Cretaceous dinosaurs.

Flora and Fauna of the Nemegt FormationEdit

CoelurosaursEdit

OviraptorosaursEdit

Oviraptorosaurs reported from the Nemegt Formation
Genus Species Location Stratigraphic Position Material Notes Images

Ajancingenia

Ajancingenia yanshini

  • Red Beds of Hermiin Tsav[1]

"Partial skeleton with skull [and five] partial postcrania."[1]

An oviraptorid, also found in the Barun Goyot Formation.

Avimimus

Avimimus portentosus

Avimimids.

Elmisaurus

Elmisaurus rarus

"[Three] pedes [and a] manus."[1]

A caenagnathid.

Conchoraptor

C. gracilis

  • Omnogov
  • Red Beds of Hermiin Tsav

"Partial skeleton wwith skull, [four] partial skulls, [and] numerous skull and postcranial fragments."[1]

Nemegtomaia

Nemegtomaia barsboldi

An oviraptorid.

Nomingia

N. gobiensis

"Partial postcranium."[2]

Rinchenia

Rinchenia mongoliensis

"Skull and fragmentary postcranium."[2]

An oviraptorid.

ParaviansEdit

Paravians reported from the Nemegt Formation
Genus Species Location Stratigraphic Position Material Notes Images

Adasaurus[3]

Adasaurus mongoliensis[3]

"Partial skull and fragmentary postcrania."[4]

A dromaeosaurid.

Borogovia

Borogovia gracilicrus

"Partial hindlimbs."[5]

A troodontid.

Gurilynia

Gurilynia nessovi

"Shoulder girdle and forelimb elements."[6]

An enantiornithine.

Judinornis

Judinornis nogontsavensis

"Vertebra."[7]

A hesperornithine.

Saurornithoides

S. junior

Reclassified as Zanabazar junior

Teviornis

Teviornis gobiensis

An anseriform related to modern ducks and geese.

Tochisaurus

Tochisaurus nemegtensis

A metatarsus.[5]

A troodontid.

Zanabazar[8]

Zanabazar junior[3]

"Skull with fragmentary postcranial skeleton."[5]

A troodontid.

Other coelurosaursEdit

Misc Coelurosaurs reported from the Nemegt Formation
Genus Species Location Stratigraphic Position Material Notes Images

Alioramus[3]

Alioramus remotus[3]

A tyrannosaur, actually present in the Beds of Nogoon Tsav. Nemegt fossils reclassified as A. altai.

Alioramus altai

A tyrannosaur.

Anserimimus

Anserimimus planinychus

"Incomplete postcranium."[9]

An ornithomimid.

Bagaraatan

Bagaraatan ostromi

"Fragmentary skull and associated postcranium."[10]

A coelurosaur or uncertain classification.

Deinocheirus[3]

Deinocheirus mirificus[3]

"Forelimb elements, skull. Two new specimens together provide a nearly complete skeleton."[9]

A gigantic ornithomimosaur.

Gallimimus[3]

Gallimimus bullatus[3]

"[Three] nearly complete skeletons, complete postcranium, skull with associated frgamentary postcranium, [and] other fragmentary postcrania.",[9] and two full skeletons "[11]

An ornithomimid.

Mononykus

Mononykus olecranus

An alvarezsaurid.

Raptorex[12]

Raptorex kreigsteni[12]

A tyrannosaurid, may be a juvenile Tarbosaurus.[13]

Tarbosaurus[3]

Tarbosaurus bataar[3]

"A skull and [Two] skeletons [14] A tyrannosaur. Articulated skeletons are unusually common here.

Therizinosaurus[3]

Therizinosaurus cheloniformis[3]

  • Omnogov, Mongolia
  • White Beds of Hermiin Tsav

"Forelimb elements [and a] referred hindlimb."[15]

A giant therizinosaur.

InvertebratesEdit

Invertebrates of the Nemegt Formation
Genus Species Location Stratigraphic Position Abundance Notes

Nemegtia

An ostracod.

MammalsEdit

Mammals of the Nemegt Formation
Genus Species Location Stratigraphic Position Abundance Notes Images

Buginbaatar

Buginbaatar transaltaiensis

A multituberculate.

OrnithischiansEdit

Ornithischians of the Nemegt Formation
Genus Species Location Stratigraphic Position Material Notes Images

Barsboldia

Barsboldia sicinskii

"Sacrum [and] pelvis."[16]

A hadrosaurid.

Dyoplosaurus

Dyoplosaurus giganteus

An ankylosaur. Formerly synonymized with Tarchia kielanae, now considered a nomen dubium.[17]

Homalocephale

Homalocephale calathoceros

A pachycephalosaur.

Prenocephale

P. prenes

"Complete skull with associated partial postcranium."[18]

Saurolophus

Saurolophus angustirostris

"At least [fifteen] specimens, including articulated skull and postcranial skeleton."[16]

A hadrosaurid.

Tarchia

Tarchia kielanae

"Complete skull" [19] An ankylosaur, also found in the Barun Goyot Formation.

SauropodsEdit

Sauropods reported from the Nemegt Formation
Genus Species Location Stratigraphic Position Material Notes Images

Nemegtosaurus

Nemegtosaurus mongoliensis

"Skull."[20]

A titanosaur.

Opisthocoelicaudia

Opisthocoelicaudia skarzynskii

"Skeleton lacking skull and cervical series."[21]

A titanosaur.

Fossil EggsEdit

Fossil eggs found in the Nemegt Formation
Oogenus Oospecies Location Stratigraphic Position Material Notes Images

Laevisoolithus[22]

Laevisoolithus sochavai

"Whole egg with partly broken pole"[22]

Laid by a bird or small theropod.[22]

Subtiliolithus[22]

Subtiliolithus microtuberculatus[22]

"Eggshel fragments"[22]

ReferencesEdit


Cite error: <ref> tags exist, but no <references/> tag was found