Ilek Formation
Ilek Formation | ||
---|---|---|
Approximate paleocoordinates 54°12′N 84°36′E / 54.2°N 84.6°E | | |
Region | Western Siberia | |
Country | Russia | |
Extent | Kemerovo Oblast | |
Type section | ||
Named by | L. A. Ragozin | |
Year defined | 1935 | |
The Ilek Formation is a
formation in Western Siberia. Many different fossils have been recovered from the formation. It overlies the Late Jurassic Tyazhin Formation and underlies the Albian Kiya Formation.[1]
The formation was described by L. A. Ragozin in 1935. It consists of sands with sandstone concretions, layers of silts, clays and marls.[2] Age of the formation, according to a crude 1962 estimate, is Valanginian(?) - Hauterivian - Barremian. Its thickness varies greatly, reaching 746 m in Teguldet borehole.[3] A more recent 2024 estimate based on invertebrate and vertebrate fossils placed the age of the formation at Barremian–Aptian.[4]
Age
The Ilek Formation conformably overlies the
ostracods. The age of the Shestakovo 1 locality is poorly constrained.[5]
angiosperm pollen has been found at this locality, indicating that it is older than the Albian.[6] The upper layers of the formation do contain angiosperm pollen, indicating that part of the formation may extend into the Albian. The overlying Kiya Formation is upper Albian based on plant biostratigraphy.[1]
Fauna
Amphibians
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Kiyatriton leshchinskiyi[7] |
|
Atlas, trunk vertebrae, fragmentary dentaries, femora, humerus, and nearly complete ilium | A crown-group salamander | |
Kuzbassia sola[8] |
|
Two atlantal centra and a trunk vertebral centrum | A karaurid |
Mammaliamorphs
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Acinacodus tagaricus[9]
|
Right dentary fragment | An amphidontid mammal
|
||
Baidabatyr clivosus[10] |
|
Upper premolar | A multituberculate
|
|
Gobiconodon hoburensis[11]
|
21 upper and lower jaws. | A gobiconodont
|
||
Gobiconodon borissiaki[12]
|
A fragmentary lower jaw | A gobiconodont
|
||
Kemchugia magna[13] | A tooth | An amphilestid mammal
|
||
Kiyatherium cardiodens[14] | A maxilla | A zhangheotheriid mammal
|
||
Xenocretosuchus sibiricus[15]
|
Dental elements | A tritylodontid mammaliamorph
|
||
Yermakia domitor[13] |
|
A mandible | A tinodontid mammal
|
|
Sibirotherium rossicum[16] |
|
M1 tooth;[16] mandibular fragments[17] | A docodontan mammaliaform |
Choristoderes
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
cf. Khurendukhosaurus[18] |
|
Dorsal vertebra, sacral vertebra | A non-neochoristodere choristodere | |
"Shestakovo choristodere"[18] |
|
Fragmentary dentaries, several vertebrae, rib fragments | A possible neochoristodere
|
|
Choristodera indet.[18] |
|
Cervical centrum | May represent a taxon distinct from both Khurendukhosaurus and the Shestakovo choristodere |
Lizards
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Paramacellodidae indet.[4] |
|
|||
Platynota indet.[4] |
|
|||
Xenosauridae indet.[4] |
|
A knob-scaled lizard
|
Turtles
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Kirgizemys | A macrobaenid
|
Crocodylomorphs
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Kyasuchus saevi[19]
|
|
A partial skull | A crocodyliform
|
|
Tagarosuchus kulemzini[20] |
|
Nearly complete skull | A crocodyliform
|
Pterosaurs
Taxon | Locality | Material | Notes | Image |
---|---|---|---|---|
?Ctenochasmatidae indet.[13] |
|
|||
cf. Lonchognathosaurus sp.[21] |
|
Wing metacarpal fragment | A dsungaripterid
|
|
Ornithocheiridae indet.[22] |
|
|||
Pterodactyloidea indet.[13] |
|
Dinosaurs
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Evgenavis nobilis[23]
|
A set of limb elements | A confuciusornithiform
|
||
Mystiornis cyrili[24]
|
|
Isolated metatarsus | An enantiornithean
|
|
Paraves indet.[25] | Teeth | May belong to either Microraptorinae or Troodontidae
|
||
Theropoda indet.[26] |
|
Partial cervical vertebra | A long-necked theropod, possibly similar to therizinosauroids like Falcarius
|
|
Tyrannosauroidea indet.[25] | Teeth | |||
cf. Urbacodon sp.[25] | Teeth | A troodontid with unserrated teeth |
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Lithostrotia indet.[27] | Caudal vertebrae | Potentially three distinct taxa of titanosaur
|
||
Sibirotitan astrosacralis[5]
|
|
Vertebrae, sacrum, and pedal elements | A somphospondylan sauropod
|
Taxon | Locality | Material | Notes | Images |
---|---|---|---|---|
Ornithischia indet.[4] |
|
Isolated teeth | Originally identified as two distinct "hypsilophodontid" taxa[29] | |
Psittacosaurus sibiricus[30]
|
|
Several skeletons | A ceratopsian | |
Stegosauria indet.[13] |
|
Isolated teeth[29] |
See also
References
- ^ S2CID 140540821.
- ISBN 9785458366533.
- ^ Лебедев И. В., ed. (1962). Биостратиграфия мезозойских и третичных отложений Западной Сибири. pp. 168–169.
- ^ .
- ^ ISSN 0016-6995.
- ^ Bugdaeva, E V; Markevich, V S; Volynets, E B (2017). "Palaeoenvironmental and palaeoclimatic reconstruction of the Early Cretaceous psittacosaur localities, Asia". Proceedings and Field Guidebook for the Fifth International Symposium of International Geoscience Programme IGCP Project 608. Fifth International Symposium of International Geoscience Programme. Jeju Island, Korea. pp. 31–34.
- ISSN 0195-6671.
- .
- ^ A. V. Lopatin; E. N. Maschenko & A. O. Averianov (2010). "A new genus of triconodont mammals from the Early Cretaceous of Western Siberia". Doklady Biological Sciences. 433 (1): 282–285. doi:10.1134/S0012496610040137.
- ^ Alexander Averianov; Alexey Lopatin; Pavel Skutschas; Stepan Ivantsov; Elizaveta Boitsova; Ivan Kuzmin (2017). "An enigmatic multituberculate mammal from the Early Cretaceous of Siberia, Russia". Journal of Vertebrate Paleontology. 37 (2): e1293070. doi:10.1080/02724634.2017.1293070.
- ^ Trofimov, B. A. (1978). "The first triconodonts (Mammalia, Triconodonta) from Mongolia". Doklady Akademii Nauk SSSR. 243 (1): 213–216.
- ^ Maschenko, E. N.; Lopatin, A. V. (1998). "First record of an Early Cretaceous triconodont mammal in Siberia". Bull. Inst. R. Sci. Nat. Belg. 68: 233–236.
- ^ .
- ^ E. N. Maschenko and A. V. Lopatin. 2002. A new Early Cretaceous mammal from Western Siberia. Doklady Biological Sciences 386:475-477
- ^ "Fossilworks: Stereognathus".
- ^ ISSN 1028-334X.
- .
- ^ ISSN 0195-6671.
- ^ Efimov, M. B. and Leshchinskiy, S. V. (2000). First finding of the fossil crocodile skull in Siberia [in Russian]. In: Komarov, A. V., ed., Materialy regional’noj konferencii geologov Sibiri, Dal’nego Vostoka i Severo−Vostoka Rossii. Tom II, 361–363. GalaPress, Tomsk.
- ^ Fiorelli, L.E.; Calvo, J.O. (2007). "The first "protosuchian" (Archosauria: Crocodyliformes) from the Cretaceous (Santonian) of Gondwana" (PDF).
- S2CID 248136173.
- ^ Skutschas, P. (2006). "Mesozoic amphibians from Siberia, Russia". 9th International Symposium on Mesozoic Terrestrial Ecosystems and Biota, Abstracts and Proceedings Volume: 123–126.
- ^ O'Connor, JL; Averianov, AO; Zelenkov, NV (2014). "A confuciusornithiform (Aves, Pygostylia)-like tarsometatarsus from the Early Cretaceous of Siberia and a discussion of the evolution of avian hind". Journal of Vertebrate Paleontology. 34 (3): 647–656. doi:10.1080/02724634.2013.828734.
- ^ Evgeny N. Kurochkin; Nikita V. Zelenkov; Alexandr O. Averianov; Sergei V. Leshchinskiy (2011). "A new taxon of birds (Aves) from the Early Cretaceous of Western Siberia, Russia". Journal of Systematic Palaeontology. 9 (1): 109–117. doi:10.1080/14772019.2010.522202.
- ^ ISSN 0206-0477.
- ISSN 0272-4634.
- S2CID 210619334.
- .
- ^ a b Averianov, A. O.; Leshchinskiy, S. V.; Skutschas, P. P.; Fayngertz, A. V.; Rezvyi, A. S. (2004). "Dinosaurs from the Early Cretaceous Ilek Formation in West Siberia, Russia". Second European Association of Vertebrate Paleontologists Meeting. Abstracts of Papers. 6: 6.
- ^ Averianov, Alexander O.; Voronkevich, Alexei V.; Leshchinskiy, Sergei V.; Fayngertz, Alexei V. (2006). "A ceratopsian dinosaur Psittacosaurus sibiricus from the Early Cretaceous of West Siberia, Russia and its phylogenetic relationships". Journal of Systematic Palaeontology. 4 (4): 359–395. doi:10.1017/s1477201906001933.