Geological formation in Kazakhstan
Chakpaktas Formation (also known as the Chakpaktas svita) is a geological formation in eastern Kazakstan , as well as being the lowest fossil-bearing strata of the Zaysan Depression . The formation is aged to the Arshantan Asian Land Animal Age which correlates to between the upper Ypresian and lower Lutetian .
Geology
The Chakpaktas formation is made up of 29 meters of deposits with the sediment transitioning from mudstone to sandstone around midway through. It contains interbedding of quartz and pebbles at the lower parts of the deposit. The mammal localities of the formation can only be found in the southeastern part of the basin which falls in between the Kalmakpay Mountain and Kendyrlyk River.
Paleobiota
Artiodactyla
Crocodilia
Genus
Species
Notes
Image
Pristichampsus
P. kuznetsov
A more terrestrial crocodilian, the genus is of questionable validity as some species have been moved to other genera. It is not completely known where the material attributed to the species is found, though it is most likely to have come from the Chakpaktas Formation.
Dinocerata
Genus
Species
Notes
Image
Gobiatherium
G. mirificum
A long-skulled uintathere with an inflated nasal region and flared zygomatic arches similair in shape to what's seen in entelodonts .
Perissodactyla
Genus
Species
Notes
Image
Eoletes
E. tshakpaktasensis
A hyrachyid known from a fairly complete skull,larger than other species within the genus like E. tianshanicus . It was originally described as the genus Subhyrachyus .
Isectolophus
I. latidens
An isectolophid perissodactyl that helped to confirm the correlation between the Arshantan and Bridgerian land animal ages. The animal lacked the postcanine diastema seen in most ungulates.
Rhodopagus
"R". radinskyi
A hyracodontid that has been noted to be within its own genus rather than being assigned to the genus Rhodopagus .
Rodentia
Testudine
Genus
Species
Notes
Image
Altaytrionyx
A. devjatkini
A trionychid turtle.
Geiselemys
G. sp.
A geoemydid turtle that was originally described under the genus grayemys .
Paraplastomenus
P. cf. mlynarskii
A medium-sized trionychid with a large amount of medial contact of the hyopastra and hypoplastra.
References
^ Lucas, Spencer G.; Holbrook, Luke T.; Emry, Robert J. (2003-04-11). "Isectolophus (Mammalia, Perissodactyla) from the Eocene of the Zaysan Basin, Kazakstan and its biochronological significance" . Journal of Vertebrate Paleontology . 23 (1): 238–243. doi :10.1671/0272-4634(2003)23[238:impfte]2.0.co;2 . ISSN 0272-4634 .
Paepen, Marieke; Li, Hong; Sun, Yan; Smith, Thierry (July 2021). "A late early to early middle Eocene mammal assemblage from Bayan Ulan (Inner Mongolia, China): Implication for the reassessment of the Arshantan Asian Land Mammal Age" . Geobios . 66–67: 177–191. Bibcode :2021Geobi..66..177P . doi :10.1016/j.geobios.2020.11.001 . hdl :1854/LU-8685269 . ISSN 0016-6995 .
^ Lucas, Spencer G. (February 2001). "Gobiatherium (Mammalia: Dinocerata) from the Middle Eocene of Asia: Taxonomy and biochronological significance" . Paläontologische Zeitschrift . 74 (4): 591–600. Bibcode :2001PalZ...74..591L . doi :10.1007/bf02988166 . ISSN 0031-0220 .
^ Trikhunkov, Ya. I.; Tesakov, A. S.; Bachmanov, D. M.; Syromyatnikova, E. V.; Latyshev, A. V.; Bulanov, S. A.; Azelkhanov, A. Zh.; Suyekpaev, E. S. (2023-11-15). "Stratigraphy of Cenozoic Deposits and the History of the Latest Stage of Geological Development of the Zaisan Depression (Eastern Kazakhstan)" . Stratigraphy and Geological Correlation . 31 (6): 612–631. Bibcode :2023SGC....31..612T . doi :10.1134/s0869593823060126 . ISSN 0869-5938 .
Lucas, Spencer G.; Bray, Emily S.; Emry, Robert J.; Hirsch, Karl F. (April 2012). "DINOSAUR EGGSHELL AND THE CRETACEOUS-PALEOGENE BOUNDARY IN THE ZAYSAN BASIN, EASTERN KAZAKSTAN" . Journal of Stratigraphy . 36 (2).
^ Averianov, Alexander (1996). "Artiodactyla from the early Eocene of Kyrgyzstan" . Zoological Institute of the Russian Academy of Sciences . 25 (2–4): 359–369.
^ Prothero, Donald (2007). The Evolution of Artiodactyls . Johns Hopkins University Press. doi :10.56021/9780801887352 . ISBN 978-0-8018-8735-2 .
Brochu, Christopher A. (September 2012). "Phylogenetic relationships of Palaeogene ziphodont eusuchians and the status ofPristichampsus Gervais, 1853" . Earth and Environmental Science Transactions of the Royal Society of Edinburgh . 103 (3–4): 521–550. Bibcode :2012EESTR.103..521B . doi :10.1017/s1755691013000200 . ISSN 1755-6910 .
^ Averianov, Alexander; Godinot, Marc (2005). "Ceratomorphs (Mammalia, Perissodactyla) from the early Eocene Andarak 2 locality in Kyrgyzstan" (PDF). Geodiversitas . 27 (2): 221–237.
Li, Qian; Meng, Jin (2015-03-20). "New Ctenodactyloid Rodents from the Erlian Basin, Nei Mongol, China, and the Phylogenetic Relationships of Eocene Asian Ctenodactyloids" . American Museum Novitates (3828): 1–20. doi :10.1206/3828.1 . ISSN 0003-0082 .
Georgalis, Georgios L.; Joyce, Walter G. (April 2017). "A Review of the Fossil Record of Old World Turtles of the CladePan-Trionychidae " . Bulletin of the Peabody Museum of Natural History . 58 (1): 115–208. doi :10.3374/014.058.0106 . ISSN 0079-032X .
Claude, Julien; Zhang, Jiang-Yong; Li, Jian-Jun; Mo, Jin-You; Kuang, Xue-Wen; Tong, Haiyan (2012-12-01). "Geoemydid turtles from the Late Eocene Maoming basin, southern China" . Bulletin de la Société Géologique de France . 183 (6): 641–651. doi :10.2113/gssgfbull.183.6.641 . ISSN 1777-5817 .
Vitek, Natasha T.; Danilov, Igor G. (March 2010). "New Material and a Reassessment of Soft-Shelled Turtles (Trionychidae) from the Late Cretaceous of Middle Asia and Kazakhstan" (PDF). Journal of Vertebrate Paleontology . 30 (2): 383–393. Bibcode :2010JVPal..30..383V . doi :10.1080/02724631003617548 . JSTOR 40666162 .
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Chakpaktas Formation
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