Lower Cretaceous Ostracods from the Undurbogd Region (Southern Mongolia): Implications for Biostratigraphy and Paleoenvironments
Abstract
This study presents new findings on ostracod assemblages from the Lower Cretaceous deposits in the area surrounding Undurbogd mountain, southern Mongolia. Three species of the genus Cypridea — C. copulenta, C. trita Lubimova, 1956, and C.
unicostata Galeeva, 1955— were identified from lacustrine sediments in the study area. In Biostratigraphy, the Cypridea assemblage indicates a Lower Cretaceous age for the sediments and correlates well with ostracod-based stratigraphic frameworks of other lacustrine successions in East Asia.
Morphological analysis reveals characteristic features common to Cypridea species, such as a rostrum, ventral rib, and distinct surface ornamentation including reticulation and spines. These features suggest adaptive responses to variations in salinity and
hydrological conditions during deposition. Our study was indefined of C. copulenta, C. trita, and C. unicostata three species in Undurbogd area.
Downloads
References
Ariunchimeg, Ya., Undariya, J., Chimedtseren, A., Ganbayar, G., Uugantsetseg, B., Myagmar¬suren, J., Erdenejargal, Ch., Baasankhuu, S., Belgutei, B., Manchuk, N., Narantsetseg, Ts., Khishigsuren, S., & Otgonbaatar, D. (2024). Biostratigraphy of Mongolia. Ulaanbaatar: Udam Soyol LLC (in Mongolian).
Arp, G., & Mennerich, C. (2008). Ostracod as¬semblages, palaeoenvironment and cyclicity of Purbeck-type sediments of the Münder Forma¬tion (Lower Cretaceous, Hils Syncline, N-Ger¬many). Palaeogeography, Palaeoclimatology, Palaeoecology, 264(3-4), 230-249. https:// doi.org/10.1016/j.palaeo.2007.02.051
Choi, B. D., & Wang, Y. (2023). Nonmarine ostracod fauna from the Lower Cretaceous Shinekhudag Formation (southwest Mongo¬lia): taxonomy, biostratigraphy, and paleoecol¬ogy. Journal of Paleontology, 97(3), 612-630. https://doi.org/10.1017/jpa.2023.5
Choi, B. D., Jia, B., Huh, M., Jung, J., & Wang, Y. (2021). Taxonomy, biostratigraphic and paleoecological aspects of non-marine ostracod fauna from the Jinju Formation (Albian) of the Gyeongsang Basin, South Korea. Creta¬ceous Research, 127, 104944. https://doi. org/10.1016/j.cretres.2021.104944
Coimbra, J. C. (2020). The genus Cypridea (Crus¬tacea, Ostracoda) and the age of the Quiricó Formation, SE Brazil: a critical review. Revis¬ta Brasileira de Paleontologia, 23(2), 90-97. DOI:10.4072/rbp.2020.2.02
Galeeva, L. I. (1955). Ostracoda from the Cre¬taceous Deposits of the People’s Republic of Mongolia”. Gost. Tech. Dat. Moscow, 95. (In Russian)
Gou, Y. X., Wang, Z. Z., Yang, J. D., & Wang, W. S. (1986). Cretaceous Ostracoda from Eren Basin of Nei Mongol along with sedi¬mentary environments. Eastern Chinese Meso¬zoic and Tertiary ecology, ancient biology and geology, 2.
Graham, S.A., Hendrix, M.S., Johnson, C.L., Badamgarav, D., Badarch, G., Amory, J., Porter, M., Barsbold, R., Webb, L.E., and Hacker, B.R.. (2001). Sedimentary record and tectonic implications of Mesozoic rifting in southeast Mongolia: GSA Bulletin, v. 113, p. 1560–1579. https://doi.org/10.1130/0016- 7606
Hajj, L., Horne, D. J., Baudin, F., Gèze, R., & Azar, D. (2021). The first non-marine ostracod fauna from the Lower Barremian dysodiles of Lebanon. Lethaia, 54(1), 127-139. https:// doi.org/10.1016/j.cretres.2020.104732
Hasegawa, H., Ando, H., Hasebe, N., Ichinnorov, N., Ohta, T., Hasegawa, T. & Yamamoto, K. (2018). Depositional ages and character¬istics of Middle–Upper J urassic and L ower C retaceous lacustrine deposits in southeastern Mongolia. Island Arc, 27(3), e12243. https:// doi.org/10.1111/iar.12243
Horne, D. J. (1995). A revised ostracod bio¬stratigraphy for the Purbeck-Wealden of En-gland. Cretaceous Research, 16(6), 639-663. https://doi.org/10.1006/cres.1995.1040
Horne, D. J., & Martens, K. (1998). An assess¬ment of the importance of resting eggs for the evolutionary success of Mesozoic non-marine cypridoidean Ostracoda (Crustacea). Archiv für Hydrobiologie, 52, 549-561.
Horne, D.J.(2009).Purbeck–Wealden, in Whit¬taker, J.E., and Hart, M.B., eds., Ostracods in British Stratigraphy. The Geological Society, Micropalaeontological Society Special Publi¬cation 3: London, The Geological Society of London, p. 289–308.
Hou, Y., & Gou, Y. (2002). Fossil ostracoda of China.
Johnson, C. L., Greene, T. J., Zinniker, D. A., Moldowan, J. M., Hendrix, M. S., & Carroll, A. R. (2003). Geochemical characteristics and correlation of oil and nonmarine source rocks from Mongolia. AAPG bulletin, 87(5), 817- 846.
Jones, T. R. (1885). On the Ostracoda of the Purbeck Formation; with notes on the Wealden species. Quarterly Journal of the Geological So¬ciety, 41(1-4), 311-353.
Khand, Yo.(2011). Animal of invertebrate in Moin¬golia secion II. Paleontology, 286-315.
Khand, E., Munkhtsetseg, J., & Badamgarav, D. (2016). On the stratigraphy of the reference section of the Upper Mesozoic deposits of Un¬dur-Bogd in southern Mongolia. Paleontolog¬ical Journal, 50(12), 1418-1420. https://doi. org/10.1134/S0031030116120091
Lubimova, P.S.(1956). Ostracoda from Cretaceous deposits of the eastern part of the People’s Re¬public of Mongolia and their significance for stratigraphy, v. 93: St. Petersburg, VNIGRI, 174 p. [in Russian]
Martinson, G. G., & Shuvalov, V. F. (1973). Stratigraficheskoye verkhney yury I nizhnego mela yugo-vostochnoy Mongolii: Akad. Nauk SSSR. Izvestiya Akademii Nauk SSSR, Seriya Geologicheskaya, 10, 139-143.
Neustrueva, I. Y., Sinitsa, S. M., Khand, Y., & Melinikova, L. M. (2005). Palaeontology of Mongolia: Late Mesozoic and Paleogene Os¬tracoda. Sames, B. (2011). Early Cretaceous Theriosyn¬oecum Branson 1936 in North America and Europe. Micropaleontology, 291-344. https:// doi:10.47894/mpal.57.4.02
Scoblo, V. M., & Lyamina, N. A. (1980). Me¬sozoic ostracods of Western Transbaikalia: A reference guide. Irkutsk: Vostochno-Sibirskaya Pravda Publishing House, 226 pp.
Sinitsa, A. L. (2018). Fertility rates in Russian regions: Convergence or divergence. Regional Research of Russia, 8(2), 169-177 (in Rus¬sian).
Wang, Y., Sha, J., & Pan, Y. (2013). Revision of Cypridea (non-marine Ostracoda) from the ear¬ly cretaceous Yixian Formation of the Beipiao– Yixian basin in western Liaoning, northeast China. Cretaceous
Wang, Y., Sha, J., Pan, Y., & Zhang, X. (2015). Early Cretaceous nonmarine ostracod biostratig¬raphy of western Liaoning area, NE China. Mi¬cropaleontology 135-145. Research, 40, 102- 109. https://doi:10.1016/j.cretres.2012.06.001
Wang, Y., Sha, J., Pan, Y., & Zhang, X. (2015). Early Cretaceous nonmarine ostracod biostra¬tigraphy of western Liaoning area, NE China. Micropaleontology, 135-145.
Wang, Y., Sha, J., Pan, Y., & Zhang, X. (2015). Early Cretaceous nonmarine ostracod biostra¬tigraphy of western Liaoning area, NE Chi¬na. Micropaleontology, 135-145. https:// DOI:10.47894/mpal.61.1.10
Wang, Y., & Zhong, Y. (2022). Temporal con¬straints on the terrestrial biota from the Yingzui¬lazi Formation (Baishan Basin), northeast Chi¬na. Cretaceous Research, 138, 105275. https:// doi.org/10.1016/j.cretres.2022.105275
Yang, Y. C., Spalholz, B. A., Rabson, M. S., & Howley, P. M. (1985). Dissociation of trans-forming and trans-activation functions for bo¬vine papillomavirus type 1. Nature, 318(6046), 575-577.
Yondon, K., Sames, B., & Schudack, M. E. (2007). New ostracod species from the non-ma¬rine Cretaceous of Mongolia. Revista española de micropaleontología, 39(1-2), 71-80.
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Geological Issues
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
