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).[1]
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.[2]
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.[2]
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.[2]
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.[2] 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.
| Lizards of the Bissekty Formation
|
| Genus |
Species |
Location |
Stratigraphic position |
Abundance |
Notes
|
| Buckantaus
|
B. crassidens
|
|
|
|
A macrocephalosaurid
|
| Ekshmer
|
E. bissektensis
|
|
|
|
A priscagamid
|
Mammals and other therapsids
Plesiosaurs
Pterosaurs
| Pterosaurs of the Bissekty Formation
|
| Genus |
Species |
Location |
Stratigraphic position |
Abundance |
Notes |
Images
|
| Azhdarcho
|
A. lancicollis
|
Dzhara-Kuduk
|
Taykarshinskaya unit
|
|
An azhdarchid
|
|
Ray-finned fish
An indeterminate acipenserid. An indeterminate albulid (bonefish) species. An indeterminate albulid (bonefish) species. An indeterminate pholidophoriform species.
Dinosaurs
Sauropods
Ornithischians
|
|
|
|
Color key
|
|
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.
|
Theropods
An indeterminate tyrannosauroid species, known from isolated teeth.[10]
Carcharodontosauridae
| Carcharodontosaurs of the Bissekty Formation
|
| Genus |
Species |
Location |
Stratigraphic position |
Material |
Description |
Images
|
| Carcharodontosauridae
|
Indeterminate
|
|
|
A partial posterior dorsal vertebra[11]
|
|
|
| Ulughbegsaurus
|
U. uzbekistanensis
|
|
|
A left maxilla, the ramus end of a left maxilla, and the posterior end of a right maxilla.
|
A probable carcharodontosaurid theropod
|
|
Enantiornithines
Other Theropods
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.
| Molluscs of the Bissekty Formation
|
| Genus |
Species |
Location |
Stratigraphic position |
Abundance |
Notes
|
| Crassatelites
|
Indeterminate
|
|
|
|
A marine crassatellid bivalve
|
| Mytiloides
|
M. labiatus
|
|
|
|
A marine inoceramid bivalve
|
| Plagiostoma
|
Indeterminate
|
|
|
|
A marine limoid bivalve
|
| Quadratotrigonia
|
Indeterminate
|
|
|
|
A marine trigoniid bivalve
|
| Xylophaga
|
Indeterminate
|
|
|
|
An indeterminate species of marine shipworm
|
References
- ^ Averianov, Alexander; Sues, Hans-Dieter (April 2012). "Skeletal remains of Tyrannosauroidea (Dinosauria: Theropoda) from the Bissekty Formation (Upper Cretaceous: Turonian) of Uzbekistan". Cretaceous Research. 34: 284–297. Bibcode:2012CrRes..34..284A. doi:10.1016/j.cretres.2011.11.009. ISSN 0195-6671.
- ^ a b c d Redman & Leighton, 2009
- ^ Grande, G; Bemis, E (2014). "A comprehensive phylogenetic study of amiid fishes (Amiidae) based on comparative skeletal anatomy. An empirical search for interconnected patterns of natural history. (project)". MorphoBank datasets. doi:10.7934/p482.
- ^ Lerzo, Lucas Nicolás; Carballido, José Luis; Gallina, Pablo Ariel (30 April 2021). "¿Saurópodos Rebbaquisáuridos en Asia? Una Re-Evaluación de la Posición Filogenética de Dharatitanis Kingi del Cretácico Tardío de Uzbekistán". Publicación Electrónica de la Asociación Paleontológica Argentina. 21 (1): 18–27. doi:10.5710/PEAPA.24.03.2021.389. hdl:11336/165212. ISSN 2469-0228. S2CID 236689007.
- ^ a b c d e f g h i j k l m n o "Dinosaur distribution (Bissekty Formation)." Weishampel, et al. (2004). Pg. 594.
- ^ a b c Averianov, 2002
- ^ "Table 20.1," in Weishampel, et al. (2004). Page 442.
- ^ "Table 17.1," in Weishampel, et al. (2004). Page 367.
- ^ Sues & Averianov, 2009
- ^ Archibald, James David; Sues, Hans-Dieter; Averianov, Alexander; King, Chris; Ward, David John; Tsaruk, Oleg; Danilov, Igor; Rezvyi, Anton; Veretennikov, Boris; Khodjaev, Anvar (1998). "Precis of the Cretaceous paleontology, biostratigtaphy and sedimentology at Dzharakuduk (Turonian?-Santonian), Kyzylkum Desert, Uzbekistan". Bulletin of the New Mexico Museum of Natural History and Science. 14: 21–27.
- ^ Averianov, Alexander O.; Sues, Hans-Dieter (2024-11-06). "New evidence for the presence of carcharodontosaurid theropod dinosaurs in the Late Cretaceous of Uzbekistan". Historical Biology: 1–7. doi:10.1080/08912963.2024.2423675. ISSN 0891-2963.
- ^ a b c d e f g h Panteleev (1998). ""New species of enantiornithines (Aves: Enantiornithes) from the Upper Cretaceous of Central Kyzylkum." Russkii Ornitologicheskii Zhurnal". Ekspress-vy.PVSK. 35: 3–15.
- ^ a b c "Table 11.1," in Weishampel, et al. (2004). Page 213.
- ^ a b "Table 11.1," in Weishampel, et al. (2004). Page 216.
- ^ Kurochkin. (1996). "A new Enantiornithid of the Mongolian Late Cretaceous, and a general appraisal of the Infraclass Enantiornithes (Aves)." Russian Academy of Sciences, special issue: 50pp.
- ^ "Table 11.1," in Weishampel, et al. (2004). Page 212.
- ^ a b c "Table 11.1," in Weishampel, et al. (2004). Page 214.
- ^ "Table 8.1," in Weishampel, et al. (2004). Page 166.
- ^ Averianov, A. O.; Sues, H.-D. (2025). "A new ornithomimid theropod from the Upper Cretaceous Bissekty Formation of Uzbekistan". Journal of Vertebrate Paleontology. e2433759. doi:10.1080/02724634.2024.2433759.
- ^ "Table 10.1," in Weishampel, et al. (2004). Page 199.
- ^ "Table 9.1," in Weishampel, et al. (2004). Page 185.
- ^ Nesov, A. (1995). "Dinosaurs of Northern Eurasia: new data about assemblages, ecology and paleobiogeography." Scientific Research Institute of the Earth's Crust. St. Petersburg State University, St. Petersburg, Russia: 156 pp. + 14 pl. [in Russian with short English, German, and French abstracts].
- ^ Sues, H.-D.; Averianov, A. (2016). "Therizinosauroidea (Dinosauria: Theropoda) from the Upper Cretaceous of Uzbekistan". Cretaceous Research. 59: 155–178. Bibcode:2016CrRes..59..155S. doi:10.1016/j.cretres.2015.11.003.
- ^ Stephen L. Brusatte; Alexander Averianov; Hans-Dieter Sues; Amy Muir; Ian B. Butler (2016). "New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs". Proceedings of the National Academy of Sciences of the United States of America. 113 (13): 3447–3452. Bibcode:2016PNAS..113.3447B. doi:10.1073/pnas.1600140113. PMC 4822578. PMID 26976562.
- ^ Averianov, A.O.; Sues, H.-D. (2007). "A new troodontid (Dinosauria: Theropoda) from the Cenomanian of Uzbekistan, with a review of troodontid records from the territories of the former Soviet Union". Journal of Vertebrate Paleontology. 27 (1): 87–98. doi:10.1671/0272-4634(2007)27[87:ANTDTF]2.0.CO;2. S2CID 9743271.
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
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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