title: Extreme ecosystem instability suppressed tropical dinosaur dominance for 30 million years.
abstract: 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 δ(13)Corg 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.
authors.affiliation: Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Southampton SO14 3ZH, United Kingdom; J.Whiteside@soton.ac.uk.
authors.forename: Jessica H
authors.initials: JH
authors.lastname: Whiteside
authors.affiliation: Department of Stratigraphy, Geological Survey of Denmark and Greenland, DK-1350 Copenhagen K, Denmark;
authors.forename: Sofie
authors.initials: S
authors.lastname: Lindström
authors.affiliation: Natural History Museum of Utah, Salt Lake City, UT 84108-1214; Department of Geology & Geophysics, University of Utah, Salt Lake City, UT 84112-0102;
authors.forename: Randall B
authors.initials: RB
authors.lastname: Irmis
authors.affiliation: Department of Geology, Colby College, Waterville, ME 04901-8858; Science and Education, Field Museum of Natural History, Chicago, IL 60605;
authors.forename: Ian J
authors.initials: IJ
authors.lastname: Glasspool
authors.affiliation: Department of Earth and Environmental Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180;
authors.forename: Morgan F
authors.initials: MF
authors.lastname: Schaller
authors.affiliation: Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI 02912;
authors.forename: Maria
authors.initials: M
authors.lastname: Dunlavey
authors.affiliation: Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061;
authors.forename: Sterling J
authors.initials: SJ
authors.lastname: Nesbitt
authors.affiliation: Department of Biology, Howard University, Washington, DC 20059;
authors.forename: Nathan D
authors.initials: ND
authors.lastname: Smith
authors.affiliation: Department of Anatomical Sciences, Stony Brook University, Stony Brook, NY 11794.
authors.forename: Alan H
authors.initials: AH
authors.lastname: Turner
mesh_terms: D000818:Animals; D002247:Carbon Isotopes / Q000032:analysis; D025061:Dinosaurs; D017753:Ecosystem; D005390:Fires; D006358:Hot Temperature; D014329:Tropical Climate
chemical_list: D002247:Carbon Isotopes
keywords: Early Mesozoic; atmospheric CO2; carbon cycling; terrestrial ecosystems; wildfires