Amtgai [HMNS-GIN]: Cenomanian - Santonian, Mongolia
collected by HMNS-GIN 1993-1994, 2001

List of taxa
Where & when
Geology
Taphonomy & methods
Metadata & references
Taxonomic list
unclassified
Mollusca indet. (Linnaeus 1758)
Watabe and Suzuki 2000
molluscan shells
Osteichthyes indet. (Huxley 1880)
Watabe et al. 2004
Reptilia
Testudinata indet. (Oppel 1811)
Watabe and Suzuki 2000
Reptilia - Testudines - Lindholmemydidae
Lindholmemydidae indet. Chkhikvadze 1970
Suzuki and Narmandakh 2004 1 specimen
shell fragments
Reptilia - Testudines - Adocidae
Adocidae indet. Cope 1869
Suzuki and Narmandakh 2004 1 specimen
shell fragments
Reptilia - Testudines - Nanhsiungchelyidae
Nanhsiungchelyidae indet. Yeh 1966
Suzuki and Narmandakh 2004 1 specimen
shell fragments
Reptilia - Testudines - Trionychidae
Trionychidae indet. Gray 1825
Suzuki and Narmandakh 2004 7 specimens
shell fragments
Reptilia
Dinosauria indet. (Owen 1842)
1 specimen
930821 AMG, skull
Reptilia - Theropoda
Theropoda indet. (Marsh 1881)
2 specimens
claw, caudal; postcranium, 040802 AMT-N Tsui
Reptilia - Pachycephalosauridae
Pachycephalosauria indet. (Maryańska and Osmólska 1974)
Watabe et al. 2004 1 specimen
pachycephalosaurian cranial case
    = Amtocephale gobiensis Watabe et al. 2011
Watabe et al. 2011
MPC-D 100/1203
Reptilia
Hadrosauridae indet. Cope 1869
many fragmentary hadrosaur and ankylosaur bones. [Then later, in 2001]: hadrosaur bone elements (skull and postcranials)
    = Hadrosauroidea indet. Huene 1954
Tsogtbaatar and Chinzorig 2007
Reptilia - Ankylosauridae
Ankylosauria indet. (Osborn 1923)
many fragmentary hadrosaur and ankylosaur bones. [Then later, in 2001]: ankylosaur skull and scute fragments
    = Ankylosauridae indet. Brown 1908
Matsumoto et al. 2010
occipital condyle, 940627 AMG
Reptilia
Sauropoda indet. (Marsh 1878)
sauropod vertebrae, ribs, teeth, femur
? Sauropoda indet. (Marsh 1878)
Matsumoto et al. 2000 1 specimen
partial tibia?; 930821 AMG
Crocodylia indet. (Owen 1842)
Watabe et al. 2004
see common names

Geography
Country:Mongolia State/province:Omnogov
Coordinates: 43.6° North, 107.9° East (view map)
Paleocoordinates:45.5° North, 98.3° East
Basis of coordinate:stated in text
Altitude:857 meters
Geographic resolution:outcrop
Time
Period: Cretaceous Epoch: Late Cretaceous
Stage: Cenomanian - Santonian 10 m.y. bin: Cretaceous 5 - Cretaceous 6
Key time interval: Cenomanian - Santonian
Age range of interval: 100.5 - 83.6 m.y. ago
Stratigraphy
Formation:Baynshire
Stratigraphic resolution:bed
Stratigraphy comments: Bayn Shire

Kurumada et al. 2020: Two meaningful calcite U–Pb ages were obtained; 95.9 ± 6.0 and 89.6 ± 4.0 Ma, which are consistent with published ages from the Bayn Shire Formation.
Lithology and environment
Primary lithology:current ripples,"cross stratification",fine,white,blue lithified sandstone
Secondary lithology:gray mudstone
Lithology description: "...alternation of sandstone and mudstone layers with gray to bluish white color...Paleocurrent direction on trough cross-stratification on hard fine-grained sandstone layer is 239 degree."
Environment:fluvial indet.
Taphonomy
Modes of preservation:body
Degree of concentration:dispersed
Size of fossils:macrofossils
Preservation of anatomical detail:medium
Fragmentation:occasional
Temporal resolution:snapshot
Collection methods and comments
Collection methods:surface (in situ),field collection
Reason for describing collection:taxonomic analysis
Collectors:HMNS-GIN Collection dates:1993-1994, 2001
Collection method comments: HMNS-Hayashibara Museum of Natural Sciences
Metadata
Also known as:Amtgai Khuduk, Amtgay
Database number:127666
Authorizer:R. Benson, M. Carrano Enterer:R. Benson, M. Carrano
Modifier:M. Carrano Research group:vertebrate
Created:2012-05-21 21:22:42 Last modified:2022-03-07 10:40:21
Access level:the public Released:2012-05-21 21:22:42
Creative Commons license:CC BY
Reference information

Primary reference:
42289. M. Watabe and S. Suzuki. 2000. Report on the Japan–Mongolia Joint Paleontological Expedition to the Gobi desert, 1993. Hayashibara Museum of Natural Sciences Research Bulletin 1:17-29 [R. Benson/R. Benson/M. Carrano]

Secondary references:

50209 I. G. Danilov, R. Hirayama, V. B. Sukhanov, S. Suzuki, M. Watabe and N. S. Vitek. 2014. Cretaceous soft-shelled turtles (Trionychidae) of Mongolia: new diversity, records, and a revision. Journal of Systematic Palaeontology 12(7):799-832 [P. Mannion/J. Tennant/P. Mannion]
79239 Y. Kurumada, S. Aoki, K. Aoki, D. Kato, M. Saneyoshi, K. Tsogtbaatar, B. F. Windley and S. Ishigaki. 2020. Calcite U–Pb age of the Cretaceous vertebrate-bearing Bayn Shire Formation in the Eastern Gobi Desert of Mongolia: Usefulness of caliche for age determination. Terra Nova 32:246-252 [P. Mannion/G. Varnham/G. Varnham]
82301 Y. Matsumoto, R. Hashimoto, and T. Sonoda. 2000. Report of preparation works for Mongolian specimens in HMNS from March 1994 to December 1998. Hayashibara Museum of Natural Sciences Research Bulletin 1:113-127 [M. Carrano/M. Carrano]
82304 Y. Matsumoto, R. Hashimoto, T. Sonoda, Y. Fujiyama, B. Mifune, Y. Kawahara, and M. Saneyoshi. 2010. Report of the preparation works for Mongolian specimens in Hayashibara Museum of Natural Sciences: 1999–2008. Hayashibara Museum of Natural Sciences Research Bulletin 3:167-185 [M. Carrano/M. Carrano/M. Carrano]
41670 S. Suzuki and P. Narmandakh. 2004. Change of the Cretaceous turtle faunas in Mongolia. Hayashibara Museum of Natural Sciences Research Bulletin 2:7-14 [R. Benson/R. Benson]
55064 S. Suzuki, M. Watabe, and K. Tsogtbaatar. 2010. Report of the HMNS-MPC Joint Paleontological Expedition in 2004. Hayashibara Museum of Natural Sciences Research Bulletin 3:1-9 [M. Carrano/M. Carrano]
80572 K. Tsogtbaatar and T. Chinzorig. 2007. Mongolian hadrosaurids: paleobiogeography, dispersal and environmental relationships. The Korean Journal of Quaternary Research 21(2):49-53 [M. Carrano/M. Carrano]
42154 M. Watabe and S. Suzuki. 2000. Cretaceous fossil localities and a list of fossils collected by the Hayashibara Museum of Natural Sciences and Mongolian Paleontological Center Joint Paleontological Expedition (JMJPE) from 1993 through 1998. Hayashibara Museum of Natural Sciences Research Bulletin 1:99-108 [R. Benson/R. Benson]
44099 M. Watabe, K. Tsogtbaatar, N. Ichinnorov and R. Barsbold. 2004. Report on the Japan-Mongolia Joint Paleontological Expedition to the Gobi desert, 2001. Hayashibara Museum of Natural Sciences Research Bulletin 2:69-96 [R. Benson/R. Benson]
55298 M. Watabe, K. Tsogtbaatar, S. Suzuki and M. Saneyoshi. 2010. Geology of dinosaur-fossil-bearing localities (Jurassic and Cretaceous: Mesozoic) in the Gobi Desert: Results of the HMNS-MPC Joint Paleontological Expedition. Hayashibara Museum of Natural Sciences Research Bulletin 3:41-118 [M. Carrano/M. Carrano]
46741 M. Watabe, K. Tsogtbaatar, and R. M. Sullivan. 2011. A new pachycephalosaurid from the Baynshire Formation (Cenomanian-late Santonian), Gobi Desert, Mongolia. In R. M. Sullivan, S. G. Lucas & J. A. Spielmann (eds.), Fossil Record 3. New Mexico Museum of Natural History and Science Bulletin 53:489-497 [G. Lloyd/G. Lloyd/M. Carrano]
42291 W. Watabe and S. Suzuki. 2000. Report on the Japan–Mongolia Joint Paleontological Expedition to the Gobi desert, 1994. Hayashibara Museum of Natural Sciences Research Bulletin 1:30-44 [R. Benson/R. Benson/M. Carrano]