Itat Formation


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The Itat Formation (Russian: итатской свиты) is a geologic formation in western Siberia. It was deposited in the Bajocian to Bathonian ages of the Middle Jurassic.[1] Dinosaur remains are among the fossils that have been recovered from the formation, including the proceratosaurid Kileskus, as well fish, amphibians, mammals and many other vertebrates.[2] It is also noted for significant coal reserves, with several open pit coal mines exploiting them.

Itat Formation
Stratigraphic range: Bajocian-Bathonian
TypeGeological formation
Unit ofNazarovo depression
Sub-unitsLower, Middle and Upper members
UnderliesTyazhin Formation
OverliesIlan Formation
ThicknessAt least 100 m
Lithology
PrimarySandstone, Mudstone, Coal
OtherSiltstone
Location
Coordinates55°42′N 89°12′E / 55.7°N 89.2°E
Approximate paleocoordinates58°12′N 86°42′E / 58.2°N 86.7°E
RegionSiberia
Country Russia
ExtentKrasnoyarsk krai
Type section
Named forItatsky

Itat Formation is located in Russia

Itat Formation

Itat Formation (Russia)

Lithology

The lower section of the formation is around 50-130 m thick and consists of light grey sandstones with gravel, siltstone and rare coal beds.[3] At the Dubinino locality, the 50 m exposed section of the upper part of the formation shows an irregular rhythmic alteration of fine grained sandstone, siltstone and mudstone and coal seams typically a few tens of cm's but up to several meters thick.[1]

Locality

Most of the fossils were found in the overburden of Berezovsk coal mine, which is located in southern Krasnoyarsk Krai near the border with Kemerovo Oblast. The deposit is stratigraphically located in the upper member of the formation. The fossils were largely obtained by screenwashing of the debris. 10-15 tons of material have been processed so far.

Paleobiota

Fish

Fish of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Hybodus Indeterminate Berezovsk coal mine Upper Member Partial tooth
Acipenseriformes Indeterminate Berezovsk coal mine Upper Member Scales
Amiiformes Indeterminate Berezovsk coal mine Upper Member "Abundant vertebrae, jaws and vomer fragments, as well as isolated teeth, and numerous isolated rhomboidal scales"
Dipnoi Indeterminate Berezovsk coal mine Upper Member One complete upper tooth plate, several tooth plate fragments
Palaeonisciformes Undescribed Berezovsk coal mine Upper Member Many partial skeletons Similar to Palaeoniscinotus and Pteroniscus

Amphibians

Amphibians of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
?Eodiscoglossus[4] Indeterminate Berezovsk coal mine Upper Member Atlantal centrum Frog
Kiyatriton[5] K. krasnolutskii Berezovsk coal mine Upper Member Dentary, atlantes, trunk vertebrae and fragmentary cranial and postcranial bones Formerly known as "Berezovsk salamander B"; genus also known from Early Cretaceous Ilek Formation Salamander
Urupia[6] U. monstrosa Berezovsk coal mine Upper Member Dentary, femur, an incomplete atlas, an anterior fragment of the left dentary, and fragments of trunk vertebrae Salamander

Turtles

Turtles of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Annemys[7] Indeterminate Berezovsk coal mine Upper Member Thousands of isolated bones and several fragmented specimens, including three partial braincases and larger fragments of connected shell parts Xinjiangchelyid
Testudines Indeterminate Berezovsk coal mine Upper Member 3 distinct taxa

Lepidosauromorphs

Lepidosauromorphs of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Lepidosauromorpha Indeterminate Berezovsk coal mine Upper Member Several fragments of dentaries and maxillae Basal form similar to Marmoretta
Scincomorpha Indeterminate Berezovsk coal mine Upper Member Fused premaxillae and two dentary fragments additionally several fragmentary maxillae and dentaries Two distinct taxa, one of which is two times smaller than the other.

Choristoderes

Choristoderes of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Cteniogenys Indeterminate Berezovsk coal mine Upper Member Skull roof bones, maxillary and dentary fragments, vertebrae, ribs

Pterosaurs

Pterosaurs of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
?Rhamphorhynchidae Indeterminate Berezovsk coal mine Upper Member Numerous isolated teeth and very rare bone fragments

Crocodyliformes

Crocodyliformes of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Goniopholididae[8] Indeterminate Berezovsk coal mine Upper Member Several dozens of isolated teeth, osteoderms, and a few cranial fragments

Non-avian dinosaurs

Non Avian DInosaurs of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Kileskus[9] K. aristotocus Berezovsk coal mine Upper Member Holotype description: "premaxilla, maxilla, a mandible fragment, and several limb bone parts"; referred material includes cervical and caudal vertebrae and numerous isolated teeth Proceratosaurid
Heterodontosauridae Indeterminate Berezovsk coal mine Upper Member Isolated maxillary and dentary teeth
Mamenchisauridae[10] Indeterminate Berezovsk coal mine Upper Member Numerous isolated teeth and two platycoelous posterior caudal vertebrae Sauropod
Stegosauria[11] Indeterminate Berezovsk coal mine Upper Member Fragmentary skeletons of at least two individuals

Tritylodontids

Tritylodontids of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Stereognathus[12] Indeterminate Berezovsk coal mine Upper Member Upper and lower postcanine teeth

Mammaliaformes

Mammaliaformes of the Itat Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Amphibetulimus[13] A. krasnolutskii Berezovsk coal mine Upper Member Dentary fragments, canine and upper molar[14]
Amphitherium Indeterminate Berezovsk coal mine Upper Member Upper and lower molars and an edentulous dentary fragment
Anthracolestes[15] A. sergeii Berezovsk coal mine Upper Member Isolated teeth and edentulous dentary fragments Dryolestid
Hutegotherium[16] H. yaomingi Berezovsk coal mine Upper Member Docodontan
Itatodon[17] I. tatarinovi Berezovsk coal mine Upper Member Docodontan
Simpsonodon[16] S. sibiricus Berezovsk coal mine Upper Member Docodontan
Sineleutherus[18] S. issedonicus Berezovsk coal mine Upper Member Haramiyidan
Eutriconodonta[19] Indeterminate Berezovsk coal mine Upper Member One large tooth and several tooth fragments Large tooth similar to Gobiconodon
Multituberculata Indeterminate Berezovsk coal mine Upper Member Molariforms

Flora

Flora of the Itat Formation[1]
Genus Species Location Stratigraphic position Abundance Notes Images
Lycopodites Indeterminate Club moss
Equisetites E. asiaticus, E. cf. lateralis Stem-horsetail
Coniopteris C. hymenophylloides, C. simplex, C. cf. maakiana Fern
Cladophlebis C. denticulata Fern
Gonatosorus G. cf mrassiensis Fern
Todites T. cf. princeps Fern
Lobifolia Indeterminate Fern
Rhizomopteris Indeterminate Fern
Ginkgo Indeterminate, G. ex gr. insolita Genus extant
Podozamites Indeterminate Gymnosperm
Sphenobaiera Indeterminate Ginkgoales
Stenorachis S. cf. scanicus Gymnosperm
Czekanowskia Indeterminate Ginkgoales

See also

References

  1. ^ a b c Ivantsov, S. V.; Bystritskaya, L. I.; Krasnolutskii, S. A.; Lyalyuk, K. P.; Frolov, A. O.; Alekseev, A. S. (September 2016). "Middle Jurassic continental biota and paleolandscape in the Dubinino locality (Sharypovo area, Krasnoyarsk krai)". Stratigraphy and Geological Correlation. 24 (5): 486–502. doi:10.1134/s0869593816050038. ISSN 0869-5938.
  2. ^ "Middle Jurassic vertebrate assemblage of Berezovsk coal mine in western Siberia (Russia)". Global Geology. 19 (4): 187–204. 2016. doi:10.3969/j.issn.1673-9736.2016.04.01.
  3. ^ "THE ILANSK FORMATION AND ITS STRATOȚYPE". Russian Geology and Geophysics.
  4. ^ Skutschas, Pavel P.; Martin, Thomas; Krasnolutskii, Sergei A. (2016-02-24). "First Jurassic frog from Siberia, Russia". Journal of Vertebrate Paleontology. 36 (3): e1101376. doi:10.1080/02724634.2016.1101376. ISSN 0272-4634.
  5. ^ Skutschas, Pavel P. (2015-10-28). "A new crown-group salamander from the Middle Jurassic of Western Siberia, Russia". Palaeobiodiversity and Palaeoenvironments. 96 (1): 41–48. doi:10.1007/s12549-015-0216-x. ISSN 1867-1594.
  6. ^ P. P. Skutschas & S. A. Krasnolutskii (2011). "A new genus and species of basal salamanders from the Middle Jurassic of western Siberia, Russia" (PDF). Proceedings of the Zoological Institute RAS. 315 (2): 167–175.
  7. ^ Danilov, I. G.; Obraztsova, E. M.; Boitsova, E. A.; Skutschas, P. P. (March 2018). "Diversity of Middle Jurassic Turtles from the Berezovsk Quarry Locality, Krasnoyarsk Region, Russia: Morphology and Histological Study". Paleontological Journal. 52 (2): 188–200. doi:10.1134/s0031030118010070. ISSN 0031-0301.
  8. ^ Kuzmin, I.T.; Skutschas, P.P.; Grigorieva, O.I.; Krasnolutskii, S.A. (2013). "Goniopholidid crocodylomorph from the Middle Jurassic Berezovsk Quarry locality ( Western Siberia, Russia)". Proceedings of the Zoological Institute of the Russian Academy of Sciences. 317 (4): 452–458.
  9. ^ Averianov, A. O.; Krasnolutskii, S. A.; Ivantsov, S. V. (2010). "A new basal coelurosaur (Dinosauria: Theropoda) from the Middle Jurassic of Siberia". Proceedings of the Zoological Institute. 314 (1): 42–57.
  10. ^ Averianov, Alexander; Krasnolutskii, Sergei; Ivantsov, Stepan; Skutschas, Pavel; Schellhorn, Rico; Schultz, Julia; Martin, Thomas (2019-03-01). "Sauropod remains from the Middle Jurassic Itat Formation of West Siberia, Russia". PalZ. doi:10.1007/s12542-018-00445-8. ISSN 0031-0220.
  11. ^ Averianov, A.O.; Krasnolutskii, S.A. (2009). "Stegosaur remains from the Middle Jurassic of West Siberia". Proceedings of the Zoological Institute RAS. 313 (2): 153–167.
  12. ^ Averianov, Alexander O.; Martin, Thomas; Lopatin, Alexey V.; Schultz, Julia A.; Skutschas, Pavel P.; Rico, Schellhorn; Krasnolutskii, Sergei A. (2017-09-03). "A tritylodontid synapsid from the Middle Jurassic of Siberia and the taxonomy of derived tritylodontids". Journal of Vertebrate Paleontology. 37 (5): e1363767. doi:10.1080/02724634.2017.1363767. ISSN 0272-4634.
  13. ^ Lopatin, A. V.; Averianov, A. O. (December 2007). "The earliest Asiatic pretribosphenic mammal (Cladotheria, Amphitheriidae) from the Middle Jurassic of Siberia". Doklady Biological Sciences. 417 (1): 432–434. doi:10.1134/s0012496607060063. ISSN 0012-4966.
  14. ^ Averianov, Alexander; Martin, Thomas; Lopatin, Alexey; Krasnolutskii, Sergei (2013-12-22). "Stem therian mammal Amphibetulimus from the Middle Jurassic of Siberia". Paläontologische Zeitschrift. 89 (2): 197–206. doi:10.1007/s12542-013-0217-x. ISSN 0031-0220.
  15. ^ Averianov, Alexander O.; Martin, Thomas; Lopatin, Alexey (2014-06-07). "The oldest dryolestid mammal from the Middle Jurassic of Siberia". Journal of Vertebrate Paleontology. 34 (4): 924–931. doi:10.1080/02724634.2014.837471. ISSN 0272-4634.
  16. ^ a b "New docodontians from the Middle Jurassic of Siberia and reanalysis of docodonta interrelationships" (PDF). Proceedings of the Zoological Institute RAS. 314 (2): 121–148. 2010.
  17. ^ Lopatin, A. V.; Averianov, A. O. (November 2005). "A New Docodont (Docodonta, Mammalia) from the Middle Jurassic of Siberia". Doklady Biological Sciences. 405 (1–6): 434–436. doi:10.1007/s10630-005-0158-y. ISSN 0012-4966.
  18. ^ A. O. Averianov, A. V. Lopatin and S. A. Krasnolutskii (2011). "The first Haramiyid (Mammalia, Allotheria) from the Jurassic of Russia". Doklady Biological Sciences. 437 (1): 103–106. doi:10.1134/S0012496611020074.
  19. ^ Averianov, A. O.; Lopatin, A. V.; Krasnolutskii, S. A. (2008). "An amphilestid grade eutriconodontan from the Middle Jurassic of Russia". Russian Journal of Theriology. 7 (1): 1–4.