Luis A. Buatois*, M. Gabriela Mángano*

Dept. of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon SK S7N 5E2, Canada

Abstract

Tracking biodiversity changes based on body fossils through geologic time became one of the main objectives of paleontology in the 1980s. Trace fossils represent an alternative record to evaluate secular changes in diversity. A quantitative ichnologic analysis, based on a comprehensive and global data set, has been undertaken in order to evaluate temporal trends in diversity of bioturbation and bioerosion structures. The results of this study indicate that the three main marine evolutionary radiations (Cambrian Explosion, Great Ordovician Biodiversification Event, and Mesozoic Marine Revolution) detected in the body-fossil record are also expressed in the trace-fossil record. Analysis of ichnodiversity trajectories in marine environments supports Sepkoski’s logistic model, which was originally based on analysis of marine body fossils. The trace-fossil record of continental environments suggests variable rates of increases in ichnodiversity, with major radiations in the Ludlow–Early Devonian, Cisuralian, Early Jurassic, Late Cretaceous, and Eocene, and slower increases or plateaus in between these periods. Our study indicates that ichnologic information represents an independent line of evidence that yields valuable insights to evaluate paleobiologic megatrends.

Manuscript received 17 Dec. 2017. Revised manuscript received 4 July 2018. Manuscript accepted 18 July 2018. Posted 25 September 2018.

© The Geological Society of America, 2018. CC-BY-NC.

10.1130/GSATG371A.1