气候变化领域集成服务门户(CCPortal): The evolution of respiratory systems in Theropoda and Paracrocodylomorpha; the end-Triassic extinction; and the role of Late Triassic atmospheric O2 and CO2

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DOI	10.1016/j.palaeo.2020.109638
	The evolution of respiratory systems in Theropoda and Paracrocodylomorpha; the end-Triassic extinction; and the role of Late Triassic atmospheric O2 and CO2
	Hudgins M.N.; Uhen M.D.; Hinnov L.A.
发表日期	2020
ISSN	0031-0182
卷号	545
英文摘要	During the Late Triassic Period (235–201.3 Ma), Paracrocodylomorpha and Theropoda switched predatory roles, with the former filling the subsidiary predator niche and the latter filling the top predator niche at the end-Triassic extinction. Reasons for the transition in predator guilds remain unknown, but atmospheric conditions during this time, which involved high CO2 and low O2 concentration levels, may be associated with the event. Evidence of bird-like pneumatic post-crania, present in both groups as foramina and fossae, correlates with an avian-like respiratory system. This may have allowed organisms to cope with declining atmospheric O2 environments of the Late Triassic. This study estimated pO2 throughout the late Triassic using organic carbon isotope measurements from Newark-Hartford basin paleosols and examined the morphological change in skeletal remains of Theropoda, focusing on pneumatic bones, compared with Paracrocodylomorpha during the Late Triassic and across the Triassic-Jurassic boundary. With data compiled from the Paleobiology Database and published anatomical literature, the change of pneumaticity in taxa is quantified by a Pneumatic Index (PI), in which the number of pneumatized units is divided by the total number of bones examined. Patterns of pneumaticity are individually scored for the presence or absence of pneumatic bones. Morphological data are compared to corresponding femur length, estimated atmospheric O2 and CO2 level reconstructions, and an ancestral state reconstruction depicting how PI values change throughout various clades. Our results suggest that PI values in Theropoda and Paracrocodylomorpha correspond with the vacillating pO2 and pCO2 throughout the Late Triassic and into the Jurassic. High PI values are prevalent in advanced theropod taxa, while Paracrocodylomorpha PI values vary by clade with a generally negative trend throughout the Triassic. Ancestral state reconstruction analysis highlights the increasing PI values within Theropoda and clade dependent trends in Paracrocodylomorpha. This study is instrumental in reconstructing how Theropoda became evolutionarily successful and perhaps how and why the avian-like respiratory system originated. © 2020 Elsevier B.V.
英文关键词	Archosaurs; Dinosaurs; Foramina; Fossae; Paleoclimate; Pneumaticity
语种	英语
scopus关键词	anatomy; atmospheric gas; bone; carbon isotope; climate change; dinosaur; extinction; isotopic analysis; morphology; organic carbon; oxygen; paleoclimate; paleosol; skeletal remains; Triassic; Aves; Crania; Dinosauria; Theropoda
来源期刊	Palaeogeography, Palaeoclimatology, Palaeoecology
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/150565
作者单位	Department of Atmospheric, Oceanic, and Earth Sciences, George Mason University, United States
推荐引用方式 GB/T 7714	Hudgins M.N.,Uhen M.D.,Hinnov L.A.. The evolution of respiratory systems in Theropoda and Paracrocodylomorpha; the end-Triassic extinction; and the role of Late Triassic atmospheric O2 and CO2[J],2020,545.
APA	Hudgins M.N.,Uhen M.D.,&Hinnov L.A..(2020).The evolution of respiratory systems in Theropoda and Paracrocodylomorpha; the end-Triassic extinction; and the role of Late Triassic atmospheric O2 and CO2.Palaeogeography, Palaeoclimatology, Palaeoecology,545.
MLA	Hudgins M.N.,et al."The evolution of respiratory systems in Theropoda and Paracrocodylomorpha; the end-Triassic extinction; and the role of Late Triassic atmospheric O2 and CO2".Palaeogeography, Palaeoclimatology, Palaeoecology 545(2020).