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[dinosaur] Jurassic (sauropod?) gastroliths + Yudu Basin dinosaur eggs + thalattosaurs + more





Ben Creisler
bcreisler@gmail.com

Some recent papers not yet mentioned:

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J.R. Malone, J. Strasser, D.H. Malone, M.D. DâEmic, L. Brown & J.P. Craddock (2021)
Jurassic dinosaurs on the move: Gastrolith provenance and longâdistance migration.
Terra Nova (advance online publication)
doi: https://doi.org/10.1111/ter.12522
https://onlinelibrary.wiley.com/doi/10.1111/ter.12522


Here we present the detrital zircon age spectra for five (n=36, 68, 66, 41, 29) red quartzite gastroliths collected from the top of the Late Jurassic Morrison Formation in the eastern Bighorn Basin, Wyoming, USA. The detrital zircon age spectra reveal geon 17 maximum depositional ages, and age peaks that are Yavapai (geon 17), Penokean (geon 18) and Archean (>geon 25). The color, texture, composition and zircon age spectra of these exoliths are indistinguishable from those of geon 16 (i.e. Baraboo interval) quartzites present in the Laurentian midcontinent more than 1000 km to the east. We interpret that these gastroliths were ingested by dinosaurs, most likely sauropods, in the Laurentian midcontinent and then transported in their digestive tracts to the site of deposition. These data support the hypothesis of longâdistance dinosaur migration, perhaps following low energy, continentalâscale drainage systems that flowed from the Appalachian highlands to the Morrison Formation depositional basin.

Older version of text by Josh Malone...

https://digitalcommons.augustana.edu/cgi/viewcontent.cgi?article=1008&context=geogstudent

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Free pdf:

YU Cheng-Tao, FAN Xiu-Jun & ZHONG Liang-Yun (2020)
Distribution of dinosaur egg fossils and occurrence stratigraphic characteristics of Yudu Basin, Southern Jiangxi.
East China Geology 41(04): 396-402 (in Chinese)
doi:10.16788/j.hddz.32-1865/P.2020.04.011
http://www.hddz.cgsnjzx.cn/oa/darticle.aspx?type=view&id=202004011


Based on the investigation of dinosaur egg fossils sites in Yudu Basin, by studying the occurrence lithology of fossils and measured stratigraphic sections, the paper confirms that the dinosaur egg fossils are concentrated in the Late Cretaceous Zhoutian Formation, analyzes the distribution characteristics of egg fossils in the plane and columnar sections, and then discusses the lakeside-shallow lake facies sedimentary environment where dinosaurs laid eggs and autochthonous-parautochthonous burial environment of egg fossils combined with the characteristics of species, shape, number and lithologic member of unearthed fossils, which provides actual data for further study of evolution law and paleoenvironment of basins.

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(New taxon not named (for now))

Jun Chai, Da-Yong Jiang, Olivier Rieppel, Ryosuke Motani, Andrea Tintori & Patrick Druckmiller (2021)
A New Specimen of Thalattosauroidea (Reptilia, Thalattosauriformes) from the Middle Triassic (Ladinian) of Xingyi, Southernwestern China.
Journal of Vertebrate Paleontology Article: e1881965 (in Chinese)
doi: https://doi.org/10.1080/02724634.2020.1881965
https://www.tandfonline.com/doi/full/10.1080/02724634.2020.1881965

Extract (edited)

Here, we report a new thalattosaur specimen [XNGM WS-22-R5] from the Ladinian of Xingyi, Guizhou Province, southwestern China. It differs from all other thalattosaurs previously reported from China in that it shows a strong ventrally curved rostrum, which bears low-crowned and bulbous teeth.


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Free pdf:

SUN Yuan-Yuan, CUI Jie & LIU Jun (2020)
The origin and evolution of thalattosaurs.
Acta Palaeontologica Sinica 59(4): 489-498 (in Chinese)
DOI: 10.19800/j.cnki.aps.2019.034
http://gswxb.cnjournals.cn/gswxb/article/abstract/20200408

Free pdf (may take a while to download...)

http://gswxb.cnjournals.cn/gswxb/article/pdf/20200408


Thalattosaurs are one of the three major groups of top reptilian predators in the Triassic marine ecosystems, the study of which is a key to our understanding of biotic recovery from the Permo-Triassic mass extinction. Significant advancement has been achieved in the last decades in studying biodiversity and phylogeny of thalattosaurs. However, the origin of thalattosaurs and the process forming the biogeographical pattern of thalattosaurs largely remains an enigma. We review here the recent progress in the study of thalattosaurs in terms of its origin, species diversity, phylogeny and biogeography. Our review shows that a large gap exists in the research of thalattosaurs. Future research should be focused on field work in the early part of the Triassic strata to search for more primitive thalattosaurs. This is necessary to elucidate its origin. A first-hand systematic review of thalattosaurs from SW China should be performed to clarify the true biodiversity of thalattosaurs, which is also a basis for a comprehensive phylogenetic analysis of thalattosaurian relationships. Finally, the study of the physiology and paleoecology of thalattosaurs via the investigation of long bone histology and microanatomy is of great significance in establishing the process forming the biogeographical pattern of thalattosaurs.

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Free pdf:

Yan Chunbo, Li Jiangli, Cheng Long, Zhao Bi, Zou Yarui, Niu Dongyi, Chen Gang & Fang Zicheng (2021)
Strata Characteristics of the Early Triassic Nanzhang-Yuan'an Fauna in Western Hubei Province.
Earth Science 46(1): 122-135 (in Chinese)
doi: 10.3799/dqkx.2020.023
http://www.earth-science.net/cn/article/doi/10.3799/dqkx.2020.023

Free pdf:
http://www.earth-science.net/fileDQKX/journal/article/dqkxzx/2021/1/PDF/dqkxzx-46-1-122.pdf


Based on the study of fossils spots and representative sections of the Nanzhang-Yuanâan Fauna, especially the Zhangjiawan section in Yuanâan county, the lithostratigraphic characteristics of the Jialingjiang Formation was redefined between Nanzhang and Yuanâan areas. It is reasonable that the Jialingjiang Formation in those areas should be divided into three members,in which the Nanzhang-Yuanâan Fauna is mainly yielded in the upper part of Member II. The lithology yielded the Nanzhang-Yuanâan Fauna mainly consists of laminated micritic limestone intercalated with normal micrite. Through systematical fossil excavations and detailed descriptions of the Zhangjiawan section, the vertical stratigraphic distributions of the Nanzhang-Yuanâan Fauna are preliminary recognized. Marine reptile fossils could exist in almost whole strata of the upper part of Member II of the Jialingjiang Formation, but the fossil abundance and diversity change largely in different layers. The abundance and diversity are relatively higher in seven strata assemblages than others, the peak appeared at the uppermost assemblages. The horizontal paleogeographic distribution features of the fauna in those areas could be summarized as four facies belts, named A, B, C and D zones, which correspond to empty zone, marginal zone, relative enrichment zone and enrichment zone, respectively. Different zones reflect the fauna experienced from rare to rich, meanwhile the water depth gradually deepens from northeast to southwest.The distributions of the Nanzhang-Yuanâan Fauna indicate that the marine reptiles could live in restricted shallow water or lagoon environment. The research will lay a good foundation not only for the co-evolution between early marine reptiles and environment,but also for its response to the Early Triassic biological recovery.


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