The Andaikhudag Formation, in older literature referred to as Unduruh Formation or Ondorukhaa Formation, is an
Early Cretaceous
The Early Cretaceous (geochronology, geochronological name) or the Lower Cretaceous (chronostratigraphy, chronostratigraphic name) is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 143.1 ...
(
Hauterivian
The Hauterivian is, in the geologic timescale, an age in the Early Cretaceous Epoch or a stage in the Lower Cretaceous Series. It spans the time between 132.6 ± 2 Ma and 125.77 (million years ago). The Hauterivian is preceded by the Valangi ...
to
Barremian
The Barremian is an age in the geologic timescale (or a chronostratigraphic stage) between 125.77 Ma (million years ago) and 121.4 ± 1.0 Ma (Historically, this stage was placed at 129.4 million to approximately 125 million years ago) It is a ...
) geologic
formation in Mongolia.
[Andaikhudag Formation]
in the Paleobiology Database
The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.
History
The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ...
Dinosaur
Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic Geological period, period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the #Evolutio ...
remains diagnostic to the
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
level are among the fossils that have been recovered from the formation.
[Weishampel et al., 2004, pp.517-607]
Fossil content
The following fossils have been reported from the
lacustrine
A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from t ...
shale
Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of Clay mineral, clay minerals (hydrous aluminium phyllosilicates, e.g., Kaolinite, kaolin, aluminium, Al2Silicon, Si2Oxygen, O5(hydroxide, OH)4) and tiny f ...
s and secondary
sandstone
Sandstone is a Clastic rock#Sedimentary clastic rocks, clastic sedimentary rock composed mainly of grain size, sand-sized (0.0625 to 2 mm) silicate mineral, silicate grains, Cementation (geology), cemented together by another mineral. Sand ...
s of the formation:
[
;Birds
* '' Ambiortus dementjevi''][Kurochkin, 2000] - "Vertebrae and forelimb"["Table 11.1," in Weishampel et al., 2004, p.214]
* '' Holbotia ponomarenkoi''[Zelenkov & Averianov, 2015]
;Insects
* Hymenoptera
Hymenoptera is a large order of insects, comprising the sawflies, wasps, bees, and ants. Over 150,000 living species of Hymenoptera have been described, in addition to over 2,000 extinct ones. Many of the species are parasitic.
Females typi ...
** '' Kotujisca kholbotensis''[Rasnitsyn, 1991]
** '' Neoxyelula reducta''[Rasnitsyn, 1993]
** '' Palaeoichneumon townesi''[Kopylov, 2009]
* Diptera
Flies are insects of the order Diptera, the name being derived from the Greek δι- ''di-'' "two", and πτερόν ''pteron'' "wing". Insects of this order use only a single pair of wings to fly, the hindwings having evolved into advance ...
** '' Syntemna tele''[Blagoderov, 2000]
** '' Ulaia communis''[Kalugina, 1993]
* Coleoptera
Beetles are insects that form the Taxonomic rank, order Coleoptera (), in the superorder Holometabola. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 40 ...
** '' Allophalerus bontsaganensis''[Ponomarenko, 1997]
** '' Tetraphalerus notatus''[
* ]Plecoptera
Plecoptera is an order (biology), order of insects commonly known as stoneflies. Some 3,500 species are described worldwide, with new species still being discovered. Stoneflies are found worldwide, except Antarctica. Stoneflies are believed to b ...
** '' Accretonemoura radiata''[Sinitshenkova, 1987]
See also
* List of dinosaur-bearing rock formations
This list of dinosaur-bearing rock formations is a list of geologic formations in which dinosaur fossils have been documented.
* List of stratigraphic units with dinosaur body fossils
* List of stratigraphic units with dinosaur trace fossils
** ...
** List of stratigraphic units with few dinosaur genera
This is a list of stratigraphic units from which dinosaur body fossils have been recovered. Although Dinosauria is a clade which includes modern birds, this article covers only Mesozoic stratigraphic units. Units listed are all either formation ...
* Tsagaantsav Formation
References
Bibliography
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* {{citation , last=Sinitshenkova , first=N.D , year=1987 , title=Istopicheskoe razvitie vesiyanok , journal=Akademiya Nauk SSSR, Trudy Paleontologicheskogo Instituta , volume=221 , pages=1–142
Geologic formations of Mongolia
Lower Cretaceous Series of Asia
Cretaceous Mongolia
Barremian Stage
Hauterivian Stage
Shale formations
Sandstone formations
Lacustrine deposits
Paleontology in Mongolia
Formations