Chakpaktas Formation (also known as the Chakpaktas svita) is a geological formation in eastern Kazakhstan, 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.[1][2]
Geology
The Chakpaktas formation is made up of 29 meters of deposits with the sediment transitioning from mudstone to sandstone around midway through.[3] It contains interbedding of quartz and pebbles at the lower parts of the deposit.[4] 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.[5]
Paleobiota
Artiodactyla
| Genus |
Species |
Notes |
Image |
|---|
| Aksyiria[6] |
A. oligostus |
A poorly known dichobunid known from a single molar.[7] |
|
| Paraphenacodus[6] |
P. solivagus |
A large dichobunid known from a single lower molar that shows a bunodont morphology.[7] |
|
Crocodilia
| Genus |
Species |
Notes |
Image |
|---|
| Pristichampsus [4] |
P. kuznetsov |
A more terrestrial crocodilian, the genus is of questionable validity as some species have been moved to other genera.[8] 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.[4] |
|
Perissodactyla
| Genus |
Species |
Notes |
Image |
|---|
| Eoletes[9] |
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.[9] |
|
| Isectolophus[1] |
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.[1] |
|
| Rhodopagus[9] |
"R". radinskyi |
A hyracodontid that has been noted to be within its own genus rather than being assigned to the genus Rhodopagus.[9] |
|
Rodentia
| Genus |
Species |
Notes |
Image |
|---|
| Juniperimus[10] |
J. flerovi |
|
|
Testudine
| Genus |
Species |
Notes |
Image |
|---|
| Altaytrionyx[4] |
A. devjatkini |
A trionychid turtle.[11] |
|
| Geiselemys[4] |
G. sp. |
A geoemydid turtle that was originally described under the genus grayemys.[12] |
|
| Paraplastomenus[4] |
P. cf. mlynarskii |
A medium-sized trionychid with a large amount of medial contact of the hyopastra and hypoplastra.[13] |
|
References
- 1 2 3 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.
- 1 2 3 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.
- 1 2 3 4 5 6 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).
- 1 2 Averianov, Alexander (1996). "Artiodactyla from the early Eocene of Kyrgyzstan". Zoological Institute of the Russian Academy of Sciences. 25 (2–4): 359–369.
- 1 2 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 ofPristichampsusGervais, 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.
- 1 2 3 4 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.
Kazakhstan