Bayan Mandahu Formation

Bayan Mandahu Formation
Stratigraphic range: Late Cretaceous
(late Santonian?–early Campanian)
Type Geological formation
Lithology
Primary Sandstone
Location
Named for Bayan Mandahu, Inner Mongolia
Region Asia
Country  China

The Bayan Mandahu Formation (or Wulansuhai Formation) is a geological unit of "redbeds" located near the village of Bayan Mandahu in Inner Mongolia, China Asia (Gobi Desert) and dates from the Late Cretaceous Period. Laid down in the early Campanian, possibly starting in the latest Santonian, it is dated somewhat uncertainly at about 84-75 mya (million years ago).

The paleoenvironment it preserves was semi-arid and characterized by alluvial (stream-deposited) and eolian (wind-deposited) sediments. The formation is known for its vertebrate fossils, most of which are preserved in unstructured sandstone, indicating burial by wind-blown sandstorms.[1]

Contents

Fauna

The fauna of the Bayan Mandahu is very similar in composition to the nearby Djadochta Formation, and the two may have been deposited at roughly the same time. These two formations share many of the same genera, but differ in the makeup of species. For example, the most common mammal in the Djadochta is Kryptobaatar dashzevegi, while in the Bayan Mandahu, it is the closely related Kryptobaatar mandahuensis. Similarly, the dinosaur fauna of the Djadochta includes Protoceratops andrewsi and Velociraptor mongoliensis, while the Bayan Mandahu contains Protoceratops hellenikorhinus and Velociraptor osmolskae.[2]

Crocodylomorphs

Crocodylomorphs of the Bayan Mandahu Formation
Genus Species Location Stratigraphic position Abundance Notes

Shamosuchus[1]

 A mesoeucrocodylian.

Lizards

An amphisbaenian species is known from the formation.[1] An iguanian species is known from the formation.[1]

Lizards of the Bayan Mandahu Formation
Genus Species Location Stratigraphic position Abundance Notes

Adamisaurus[1]

A. magnidentatus[1]

 An agamid.

Bainguis[1]

A diploglossan.

Telmasaurus[1]

A monitor lizard.

Mammals

A taeniolabidoidea multituberculate is known from the formation.[1]

Mammals of the Bayan Mandahu Formation
Genus Species Location Stratigraphic position Abundance Notes

Kennalestes[1]

K. gobiensis[1]

A placental. Also present in the Djadochta Formation.

Kryptobaatar

K. mandahuensis

The most common mammal in this formation.[2]

A multituberculate.

Ornithischians

Ornithischian dinosaurs of the Bayan Mandahu Formation
Genus Species Location Abundance Notes Images

Hadrosauridae indet.[3]

Indeterminate[3]
  • Bayan Mandahu[3]

A hadrosaurid.

Magnirostris[2]

M. dodsoni[2]
  • Bayan Mandahu[3]

A ceratopsian.

Pinacosaurus[2]

P. mephistocephalus[2]
  • Bayan Mandahu[3]

"Skull, postcranial skeleton, osteoderms."[4]

An ankylosaur.

Protoceratops[2]

P. hellenikorhinus[2]
  • Bayan Mandahu[3]

"Complete skull."[5]

A ceratopsian.

?Udanoceratops[1]

Indeterminate[1]
  • Bayan Mandahu[3]

A giant ceratopsian.

Saurischians

Saurischian dinosaurs of the Bayan Mandahu Formation
Genus Species Location Abundance Notes Images

cf. Gobipteryx[1]

Indeterminate

Eggs similar to those attributed to Gobipteryx minuta from the Djadochta Formation.

Linheraptor[6]

L. exquisitus[6]
  • Bayan Mandahu[3]

A dromaeosaurid

Linhevenator[7]

L. tani[7]
  • Bayan Mandahu[7]

A troodontid

Machairasaurus

M. leptonychus
  • Bayan Mandahu[3]

An oviraptorid

Oviraptoridae indet.[3]

Indeterminate[3]
  • Bayan Mandahu[3]

An oviraptorid.

Sauropoda indet.[3]

Indeterminate[3]
  • Bayan Mandahu[3]

A sauropod.

cf. Saurornithoides[3]

Indeterminate[3]
  • Bayan Mandahu[3]
 A troodontid similar to Saurornithoides mongoliensis from the Djadochta Formation.

Tyrannosauridae indet.[3]

Indeterminate[3]
  • Bayan Mandahu[3]

A tyrannosaurid.

Velociraptor[1]

V. mongoliensis[1]

Misclassified, only present in the Djadochta Formation.

V. osmolskae
  • Bayan Mandahu[3]

A dromaeosaurid.

Turtles

Turtles of the Bayan Mandahu Formation
Genus Species Location Stratigraphic position Abundance Notes

Basilemys[1]

A softshell turtle.

See also

References

  1. ^ a b c d e f g h i j k l m n o p q Jerzykiewicz, T.; Currie, P.J., Eberth, D.A., Johnston, P.A., Koster, E.H., and Zheng J. (1993). "Djadokhta correlative strata in Chinese Inner Mongolia: An overview of the stratigraphy, sedimentary geology, and paleontology and comparisons with the type locality in the pre-Altai Gobi.". Canadian Journal of Earth Sciences 30: 2180–2195. doi:10.1139/e93-190.  [printed early 1994]
  2. ^ a b c d e f g h Godefroit, Pascal; Currie, Philip J.; Li Hong; Shang Chang Yong; and Dong Zhi-ming (2008). "A new species of Velociraptor (Dinosauria: Dromaeosauridae) from the Upper Cretaceous of northern China". Journal of Vertebrate Paleontology 28 (2): 432–438. doi:10.1671/0272-4634(2008)28[432:ANSOVD]2.0.CO;2. 
  3. ^ a b c d e f g h i j k l m n o p q r s t u v 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. 
  4. ^ "Table 17.1," in Weishampel, et al. (2004). Page 364.
  5. ^ "Table 22.1," in Weishampel, et al. (2004). Page 480.
  6. ^ a b Xu, X., Choinere, J., Pittman, M., Tan, Q., Xiao, D., Li, Z., Tan, L., Clark, J., Norell, M., Hone, D.W.E. and Sullivan, C. (In press). "A new dromaeosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China." Zootaxa, in press.
  7. ^ a b c Xu X., Tan Q., Sullivan, C., Han F., Xiao D. (2011) A Short-Armed Troodontid Dinosaur from the Upper Cretaceous of Inner Mongolia and Its Implications for Troodontid Evolution. PLoS ONE 6(9): e22916. doi:10.1371/journal.pone.0022916 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0022916