• Source: Bissekty Formation

The Bissekty Formation (sometimes referred to as Bissekt) is a geologic formation and Lagerstätte which crops out in the Kyzyl Kum desert of Uzbekistan, and dates to the Late Cretaceous Period. Laid down in the mid to late Turonian, it is dated to about 92 to 90 Ma (million years ago).




Description


The lithology of the sediment largely consists of cross bedded sandstones with interbeds of massive sandstone, well cemented intraformational conglomerate, siltstones and mudstones. Most of the fossils are found as clasts within the conglomerates.




Fossil content


The Bissekty Formation is characterised by a mix of marine, brackish, freshwater, and terrestrial animal fossils. This stands in contrast the strictly marine fossils found in the underlying Dzheirantui Formation, and indicates that the Bissekty was formed during the regression of a saltwater sea. The coastline expanded inland again in the upper portion of the Bissekty, represented by a proportional increase of fully aquatic species, which were almost completely absent from the middle period of the formation. Semi-aquatic species remained abundant during this middle period, and the geology of the formations indicates that a braided river system took the place of the coastline. Eventually the area was again completely underwater, during the time period represented by the later Aitym Formation, which preserves coastal marine sediments.




= Vertebrates

=
The Bissekty Formation is notable for preserving the most abundant Turonian land animal fossils in Eurasia, and the most diverse fauna of Late Cretaceous eutherians (placental mammals and relatives) in the world.
Listings and accompanying information are based on a survey of the Bissekty Formation published by Cory Redman and Lindsey Leighton in 2009 unless otherwise noted. Aquatic and semi-aquatic species are restricted to freshwater unless otherwise noted.



Amphibians

An indeterminate species of salamander-like albanerpetontid amphibian. An indeterminate gobiatid species.



Cartilaginous fish




Crocodylomorphs




Lizards

An indeterminate gekkonid. An indeterminate priscagamid. An indeterminate scincid.



Mammals and other therapsids




Plesiosaurs




Pterosaurs




Ray-finned fish

An indeterminate acipenserid. An indeterminate albulid (bonefish) species. An indeterminate albulid (bonefish) species. An indeterminate pholidophoriform species.



Dinosaurs




= Theropods
=
An unnamed ornithomimosaur, known from fragmentary remains. An indeterminate tyrannosauroid species, known from isolated teeth.



= Sauropods
=



= Ornithischians
=



= Enantiornithines
=



Turtles

An indeterminate trionychid (soft-shell) turtle species that was tolerant of brackish water.




= Invertebrates

=
An indeterminate species of marine coral.



Arthropods




Molluscs

An indeterminate species of marine placenticeratid ammonite. An indeterminate species of marine teredinid shipworm. An indeterminate marine trigoniid bivalve. An indeterminate marine veneroid bivalve.




References






= Bibliography

=
Averianov, A.O (2002), "An ankylosaurid (Ornithischia: Ankylosauria) braincase from the Upper Cretaceous Bissekty Formation of Uzbekistan" (PDF), Bulletin de l'Institut Royal des Sciences Naturelles de Belgique, Sciences de la Terre, 72: 97–110, retrieved 2019-03-22
Redman, C.M.; Leighton, L.R. (2009), "Multivariate faunal analysis of the Turonian Bissekty Formation: Variation in the degree of marine influence in temporally and spatially averaged fossil assemblages", PALAIOS, 24 (1): 18–26, Bibcode:2009Palai..24...18R, doi:10.2110/palo.2007.p07-072r, retrieved 2019-03-22
Sues, H-D.; Averianov, A. (2016), "Ornithomimidae (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan", Cretaceous Research, 57: 90–110, Bibcode:2016CrRes..57...90S, doi:10.1016/j.cretres.2015.07.012, retrieved 2019-03-22
Sues, H.-D.; Averianov, A. (2009), "Turanoceratops tardabilis—the first ceratopsid dinosaur from Asia", Naturwissenschaften, 96 (5): 645–652, Bibcode:2009NW.....96..645S, doi:10.1007/s00114-009-0518-9, PMID 19277598, retrieved 2019-03-22
Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (2004), The Dinosauria, 2nd edition, Berkeley: University of California Press, pp. 1–880, ISBN 0-520-24209-2, retrieved 2019-02-21




Further reading


Averianov, A.O.; Archibald, J.D.; Ekdale, E.G. (2010), "New material of the Late Cretaceous deltatheroidan mammal Sulestes from Uzbekistan and phylogenetic reassessment of the metatherian-eutherian dichotomy", Journal of Systematic Palaeontology, 8 (3): 301–330, Bibcode:2010JSPal...8..301A, doi:10.1080/14772011003603499, retrieved 2019-03-22
Averianov, A.O (2007), "New records of azhdarchids (Pterosauria, Azhdarchidae) from the Late Cretaceous of Russia, Kazakhstan, and Central Asia", Paleontological Journal, 41 (2): 189–197, Bibcode:2007PalJ...41..189A, doi:10.1134/S0031030107020098, retrieved 2019-03-22
Feldmann, R.M.; Schweitzer, C.E.; Redman, C.M.; Morris, N.J.; Ward, D.J. (2007), "New Late Cretaceous lobsters from the Kyzylkum Desert of Uzbekistan", Journal of Paleontology, 81 (4): 701–713, doi:10.1666/pleo0022-3360(2007)081[0701:NLCLFT]2.0.CO;2, retrieved 2019-03-22
Storrs, G.W.; Efimov, M.B. (2000), Mesozoic crocodyliforms of north-central Eurasia, In M. J. Benton, M. A. Shishkin, D. M. Unwin, E. N. Kurochkin (eds.), The Age of Dinosaurs in Russia and Mongolia, pp. 402–419, retrieved 2019-03-22
Sues, H.-D.; Averianov, A. (2014), "Dromaeosauridae (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan and the phylogenetic position of Itemirus medullaris Kurzanov, 1976", Cretaceous Research, 51: 225–240, Bibcode:2014CrRes..51..225S, doi:10.1016/j.cretres.2014.06.007, retrieved 2019-03-22
Zelenkov, N. V.; Averianov, A. O. (2011), "Synsacrum of a primitive bird from the Upper Cretaceous of Uzbekistan", Paleontological Journal, 45 (3): 314–319, Bibcode:2011PalJ...45..314Z, doi:10.1134/S0031030111030166

Kata Kunci Pencarian:

• Bissekty Formation
• Ulughbegsaurus
• Enantiornithes
• List of Asian dinosaurs
• Kyzylkum Desert
• Alvarezsauroidea
• List of stratigraphic units with dinosaur body fossils
• Bissektipelta
• Timurlengia
• Eudromaeosauria