期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：26
页码：7909-7913
DOI：10.1073/pnas.1505252112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThis is, to our knowledge, the first multiproxy study of climate and associated faunal change for an early Mesozoic terrestrial ecosystem containing an extensive vertebrate fossil record, including early dinosaurs. Our detailed and coupled high-resolution records allow us to sensitively examine the interplay between climate change and ecosystem evolution at low paleolatitudes during this critical interval of Earth's history when modern terrestrial ecosystems first evolved against a backdrop of high CO2 in a hothouse world. We demonstrate that these terrestrial ecosystems evolved within a generally arid but strongly fluctuating paleoclimate that was subject to pervasive wildfires, and that these environmental conditions in the early Mesozoic prevented large active warm-blooded herbivorous dinosaurs from becoming established in subtropical low latitudes until later in the Mesozoic. A major unresolved aspect of the rise of dinosaurs is why early dinosaurs and their relatives were rare and species-poor at low paleolatitudes throughout the Late Triassic Period, a pattern persisting 30 million years after their origin and 10-15 million years after they became abundant and speciose at higher latitudes. New palynological, wildfire, organic carbon isotope, and atmospheric pCO2 data from early dinosaur-bearing strata of low paleolatitudes in western North America show that large, high-frequency, tightly correlated variations in {delta}13Corg and palynomorph ecotypes occurred within a context of elevated and increasing pCO2 and pervasive wildfires. Whereas pseudosuchian archosaur-dominated communities were able to persist in these same regions under rapidly fluctuating extreme climatic conditions until the end-Triassic, large-bodied, fast-growing tachymetabolic dinosaurian herbivores requiring greater resources were unable to adapt to unstable high CO2 environmental conditions of the Late Triassic.
