Karabastau Formation

The Karabastau Formation (Kazakh: Qarabastaý svıtasy) is a geological formation and lagerstätte in Kazakhstan whose strata date to the Middle to Late Jurassic. It is an important locality for insect fossils that has been studied since the early 20th century, alongside the rarer remains of vertebrates, including pterosaurs, salamanders, lizards and crocodiles.[1][2]

Karabastau Formation
Stratigraphic range: Middle Jurassic - Late Jurassic Callovian–Kimmeridgian
Karaurus sharovi
TypeGeological formation
AreaKaratau Mountains
Thickness26 m (85 ft) exposed
Lithology
PrimaryClaystone dolomite,
OtherSandstone, conglomerate
Location
RegionCentral Asia
Country Kazakhstan

Lithology and depositional environment

The primary lithology consists of 1 mm thick varve laminations of claystone, with a dark part and a light dolomitic part, which probably correspond to a wet and dry season respectively, alongside rare, several cm thick sandstone interbeds. These were deposited within an ancient freshwater paleolake, that given the number of laminations has been suggested to have existed for over 150,000 years. The top of the formation shows the laminations becoming wavy, likely as a result of microbial interactions, and the top of the formation is capped by a conglomerate predominantly composed of black Carboniferous limestone pebbles.[2]

History of discovery

The Karabastau Formation was first discovered in 1921 by Soviet geologists, and was declared a protected paleontological reserve in 1924.[2]

Paleofauna

Vertebrates
Genus Species County Member Abundance Notes Images

Batrachognathus

B. volans

 2 specimens

An Anurognathid Pterosaur.
Sordes pilosus

Karatausuchus

K. sharovi

An Atoposaurid Crocodylomorph.

Karaurus

K. sharovi

stem-group salamander.

Praeornis P. sharovi 2 specimens Proto-Feather
Sharovisaurus S. karatauensis A Paramacellodid lizard

Sordes

 S. pilosus 8 specimens

A Pterodactylomorph Pterosaur.

Yaxartemys Y. longicauda Turtle
Palaeonisciformes 2 species 346 specimens 2 distinct taxa[3]

Invertebrates

Numerous species of insect are known from several localities within the formation, primarily Karatau-Mikhailovka[4][5][6][7][8][9][10][11][12][13] an extremely partial list is given here

Genus Species County Member Abundance Notes Images
Archocyrtus A. gibbosus, A. kovalevi An Acrocerid fly
Aulieezidium A. karatauense A Fulgoromorph

Auliepterix

A. mirabilis

A Micropterygid moth.

Omma [14]

O. aberatum, O. jurassicum, O. pilosum

Ommatid beetles

Mesogyrus M. antiquus Gyrinid beetle

Palaeolepidopterix

P. aurea

A Micropterygid or Eolepidopterigid moth.

Pseudopolycentropus P. latipennis Basal Mecopteran
Stenophlebia S. karatavica Stem-Dragonfly

See also

References
  1. Barrett, P.M., Butler, R.J., Edwards, N.P., & Milner, A.R. Pterosaur distribution in time and space: an atlas. p61-107. in Flugsaurier: Pterosaur papers in honour of Peter Wellnhofer. 2008. Hone, D.W.E., and Buffetaut, E. (eds). Zitteliana B, 28. 264pp.
  2. Dzik, Jerzy; Sulej, Tomasz; Niedźwiedzki, Grzegorz (2010-07-14). "Possible link connecting reptilian scales with avian feathers from the early Late Jurassic of Kazakstan". Historical Biology. 22 (4): 394–402. doi:10.1080/08912961003710616. ISSN 0891-2963.
  3. Skrzycka, Roksana (2014-07-03). "Revision of two relic actinopterygians from the Middle or Upper Jurassic Karabastau Formation, Karatau Range, Kazakhstan". Alcheringa: An Australasian Journal of Palaeontology. 38 (3): 364–390. doi:10.1080/03115518.2014.880267. ISSN 0311-5518.
  4. "Karabastau Formation". paleobiodb.org. Retrieved 2020-01-31.
  5. "Karatau-Galkino (PIN collection 1789)". Paleobiology Database.
  6. "Karatau-Mikhailovka (PIN collection 2997)". Paleobiology Database.
  7. "Karatau-Mikhailovka (PIN collection 2554)". paleobiodb.org. Retrieved 2020-01-31.
  8. "Karatau-Mikhailovka (PIN collection 2066)". paleobiodb.org. Retrieved 2020-01-31.
  9. "Karatau-Mikhailovka (PIN collection 2239)". paleobiodb.org. Retrieved 2020-01-31.
  10. "Karatau-Mikhailovka (PIN collection 2384)". paleobiodb.org. Retrieved 2020-01-31.
  11. "Karatau-Mikhailovka (PIN collection 2904)". paleobiodb.org. Retrieved 2020-01-31.
  12. "Karatau-Mikhailovka (PIN collection 2784)". paleobiodb.org. Retrieved 2020-01-31.
  13. "Karatau-Galkino (PIN collection 2452)". paleobiodb.org. Retrieved 2020-01-31.
  14. Tan, Jingjing; Wang, Yongjie; Ren, Dong; Yang, Xingke (2012). "New fossil species of ommatids (Coleoptera: Archostemata) from the Middle Mesozoic of China illuminating the phylogeny of Ommatidae". BMC Evolutionary Biology. 12: 113. doi:10.1186/1471-2148-12-113. PMC 3518168. PMID 22776212.

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