Review Paper
Dinosaur extinctions related to the Jenkyns Event (early Toarcian, Jurassic)
MATIAS REOLID
Departamento de Geología and CEACTEMA, Campus Las Lagunillas sn, Universidad de Jaén, 23071 Jaén, Spain; mreolid@ujaen.es
Corresponding author
WOLFGANG RUEBSAM
Department of Organic and Isotope Geochemistry, Institute of Geoscience, University of Kiel, Ludewig-Meyn Str. 10, 24118 Kiel, Germany; wolfgang.ruebsam@googlemain.com
MICHAEL J. BENTON
School of Earth Sciences, University of Bristol, Wills Memorial Building, Queens Road, Bristol BS8 1RJ, United Kingdom; Mike.Benton@bristol.ac.uk
ABSTRACT
The early Toarcian Jenkyns Event (~183 Ma) was characterized by a perturbation of the global carbon cycle, global warming, which at continental areas led to intensified chemical weathering, enhanced soils erosion, and intensified wildfires. Warming and acid rain affected diversity and composition of land plant assemblages, caused a loss of forests and thereby impacted on trophic webs. The Jenkyns Event, triggered by volcanic activity of the Karoo-Ferrar Large Igneous Province, changed terrestrial ecosystems, and also affected the dinosaurs. Fossil macroplant assemblages and palynological data reveal reductions in the diversity and richness of plant communities. A substantial loss of land plant biomass and a shift to forests dominated by Cheiropelidiaceae conifers occurred as a consequence of seasonally dry and warm conditions. Major changes occurred to hervivore dinosaurs, with extinction of diverse basal families of Sauropodomorpha (‘prosauropods’) as well as some basal sauropods. Ornithischian dinosaurs show patchy records; some heterodontosaurids disappeared and the scelidosaurids (Thyreophora) went extinct during the Jenkyns Event. The dominant carnivorous dinosaurs, the Coelophysoidea (Theropoda), died out during the Jenkyns Event. We interpret the Jenkyns Event as a terrestrial crisis for ecosystems, marked especially by floral changes and the extinction of some dinosaur clades, both hervivores and carnivores.
Key words: Hyperthermal Event, Dinosaur Biotic Crisis, Sauropodomorphs, Theropods, Ornithischians.
How to cite: Reolid, M. Ruebsam, W., & Benton, M.J. 2022. Dinosaur extinctions related to the Jenkyns Event (early Toarcian, Jurassic). Spanish Journal of Palaeontology, 37(2), 123-140.
Received 9 November 2022, Accepted 7 December 2022, Published online 22 December2022
https://doi.org/10.7203/sjp.25683
