Ben Creisler
Some non-dino papers not yet mentioned with free pdfs:
Chaohusaurus geishanensis, an Early Triassic ichthyopterygia found in China, shares similar forefin and skull structures and reveals a systematic relationship to Grippia in Europe. However, further intercomparison was difficult because specimens subsequently discovered in China were either highly specialized in forelimb or incomplete. Here, two nearly complete and nonâspecialized forelimbs of Chaohusaurus found in the Lower Triassic Jialingjiang Formation in Hubei Province are described with related information on basal ichthyopterygians in China. Morphological comparison reveals that the general features of the Early Triassic Chaohusaurus in the Hubei Province were close to Ch. geishanensis of the same genus, but distinctly different from Ch. chaoxianensis. Its features such as relatively large individual size, intermediate squeezing and deformation and pisiform development shares some similarities with Grippia, Utatsusaurus, Parvinatator and other Early Triassic ichthyopterygians. Based on these results we propose that there were possibly two directions for evolution of the Early Triassic ichthyopterygians. After the end- Permian mass extinction (EPME), ichthyopterygians appeared and soon differentiated during the Olenekian. Some large individuals without specialized forelimbs but with strong motor ability migrated between different regions. However, other small individuals with specialized forelimbs and weak motor ability became a local (eastern Tethys) independently evolving branch. However, the clarification of the phylogenetic relationship between them, and the monophyly of Chaohusaurus needs to be tested by future studies.
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Zhicai Zhu, ÂHongwei Kuang, ÂYongqing Liu, ÂMichael J. Benton, ÂAndrew J. Newell, ÂHuan Xu, ÂWei An, ÂShu'an Ji, ÂShichao Xu, ÂNan Peng & Qingguo Zhai (2020)
Intensifying aeolian activity following the endâPermian mass extinction: Evidence from the Late Permian-Early Triassic terrestrial sedimentary record of the Ordos Basin, North China.
Sedimentology (advance online publication)
doi: Â
https://doi.org/10.1111/sed.12716https://onlinelibrary.wiley.com/doi/abs/10.1111/sed.12716Free pdf link:
https://cpb-eu-w2.wpmucdn.com/blogs.bristol.ac.uk/dist/6/525/files/2020/04/2020Sedimentology.pdfSedimentary successions provide direct evidence of climate and tectonics, and these give clues about the causes of the mass extinction around the Permian-Triassic boundary. Terrestrial Permian-Triassic boundary strata in the eastern Ordos Basin, North China, include the Late Permian Sunjiagou, Early Triassic Liujiagou and late Early Triassic Heshanggou formations in ascending order. The Sunjiagou Formation comprises crossâbedded sandstones overlaid by mudstones, indicating meandering rivers with channel, point bar and floodplain deposits. The Liujiagou Formation was formed in braided rivers of arid sand bars interacting with some aeolian dune deposits, distinguished by abundant sandstones where diverse trough and planar crossâbedding and aeolian structures (for example, inverse climbingâripple, translatentâripple lamination, grainfall and grainflow laminations) interchange vertically and laterally. The Heshanggou Formation is a rhythmic succession of mudstones interbedded with thin mediumâgrained sandstones mainly deposited in a shallow lacustrine environment. Overall, the sharp meandering to braided to shallow lake sedimentary transition documents palaeoenvironmental changes from semiâarid to arid and then to semiâhumid conditions across the Permian-Triassic boundary. The dieâoff of tetrapods and plants, decreased bioturbation levels in the uppermost Sunjiagou Formation, and the bloom of microbiallyâinduced sedimentary structures in the Liujiagou Formation marks the mass extinction around the Permian-Triassic boundary. The disappearance of microbiallyâinduced sedimentary structures, increasingly intense bioturbation from bottom to top and the reoccurrence of reptile footprints in the Heshanggou Formation reveal gradual recovery of the ecosystem after the Permian-Triassic boundary extinction. This study is the first to identify the intensification of aeolian activity following the endâPermian mass extinction in North China. Moreover, while northern North China continued to be uplifted tectonically from the Late Palaeozoic to Late Mesozoic, the switch of sedimentary patterns across the Permian-Triassic boundary in Shanxi is largely linked to the development of an arid and subsequently semiâhumid climate condition, which probably directly affected the collapse and delayed recovery in palaeoecosystems.
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