About

David J. Bottjer is a professor of Earth Sciences, Biological Sciences, and Environmental Studies at USC Dornsife. He is a paleobiologist and paleoecologist whose work broadly focuses on organism-sediment interactions and the ecological history of life. His current research emphasizes understanding the paleobiology and paleoecology of early metazoan life through multidisciplinary approaches, with field work conducted in eastern California and China. Additionally, he investigates the paleoecology of recovery from the end-Permian and end-Triassic mass extinctions, with extensive studies on Triassic strata across the western U.S., Europe, Japan, and China. His research has contributed to the development of large databases within the Paleobiology Database to address major paleobiological and evolutionary questions. Dr. Bottjer has authored a book titled 'Paleoecology: Past, Present and Future' and has published numerous articles on topics including geobiology, paleoecology, paleoclimatology, and paleogenomics. He has received several honors, including the William H. Twenhofel Medal, the Paleontological Society Medal, and the Raymond C. Moore Medal for Excellence in Paleontology, and has served as President of The Paleontological Society and as Editor-in-Chief of key journals in his field.

Research topics

• Geology
• Paleontology
• Chemistry
• Earth science
• Geochemistry
• Environmental chemistry
• Biology
• Ecology
• Environmental science
• Oceanography

Selected publications

• Predator-prey interactions in the Early Triassic ocean

  Geological Society of America Bulletin · 2026-02-26

  article

  The Permian−Triassic mass extinction punctuated the history of life by wiping out 81%−96% of marine species, enabling the establishment of modern ecosystems. Predator-prey interactions represent a significant driving force of evolutionary change in the history of life, but are scarce and heretofore little appreciated during the Early Triassic. We report exceptionally preserved Kouphichnium trackways, burrows and trails, and a previously undocumented compound trace from the Lower Triassic Daye Formation of South China. Kouphichnium is widely attributed to limulids (horseshoe crabs), whereas the simple traces and the compound trace are most probably produced by polychaete worms. The co-occurrence and specific spatial relationships of these traces are interpreted as an unusual case of predatory interaction preserved in the act between limulid predators and their polychaete prey. A dataset of ecospace utilization of infaunal communities in shallow carbonate settings demonstrates that infaunalization was also enhanced at that time, coinciding with the diversification of marine predators. We propose that enhanced infaunalization was driven either by predation or by the amelioration of environmental conditions during the late Early Triassic. Both the snapshot of predators caught in the act of hunting their prey and the diverse predator taxa may indicate prevalent predation pressures in the Early Triassic ocean of South China.

  PublisherDOI

• Organism–sediment interactions and the evolution of a unique trilobite morphology

  Proceedings of the Royal Society B Biological Sciences · 2026-01-28

  articleOpen accessSenior author

  During the Ordovician, trilobites of the order Harpetida and the superfamily Trinucleioidea evolved unusual cephalic brims, quite unlike any structure known in modern arthropods. Brimmed trilobites were diverse and widespread, but we still do not fully understand why the harpiform brim evolved or what role it played in their success. Many authors have speculated about the brim's function, generating many untested hypotheses. We tested the hypothesis that the brim evolved to prevent sinking in soft sediments by calculating the depth to which brimless trilobites would sink and showed this explanation to be untenable. We then three-dimensionally printed model cephala with various brim shapes and moved them through natural sediments, testing the hypothesis that the brim evolved as a sediment plough. We found that increased horizontal brim width allowed a cephalon to efficiently displace more sediment, while increased brim height merely impeded the cephalon's progress. However, there is no clear evolutionary trend among harpetids or trinucleids towards wider or flatter brims, indicating that ploughing did not exert a strong selective pressure on brimmed trilobites. This work also serves as a case study in researching taxa without modern biomechanical analogues, demonstrating that many functional hypotheses can be adequately tested by straightforward experimental methods.

  PublisherDOI

• ‘EcoCleanR': enhancing data quality of biogeographic ranges with application for marine invertebrates

  Ecography · 2026-02-12

  articleOpen accessSenior author

  Published distribution data, while invaluable for understanding species' biogeography, often suffer from limitations such as dated and static representations of ranges, a bias toward latitudinal information, and lack of resolution in sampling frequency and variation in abundance throughout a species' distribution. Extensive open‐source biodiversity data now allow us to construct biogeographic ranges with more modern observations, which can be useful in conservation, evolution, and ecological studies. However, data quality remains a persistent challenge, hampering data reliability and usability. We introduce ‘EcoCleanR', an R package that integrates existing tools with new functionalities to address data integration and quality assessment through a systematic, step‐by‐step approach for marine occurrence data. This package enhances the process of identifying and resolving common issues in biodiversity data, including taxonomy and georeferencing errors. It provides: 1) example scripts to guide users, 2) functionalities to flag problematic occurrence records from multiple databases, and 3) outputs that include species‐specific distribution ranges and their corresponding environmental conditions, to facilitate accurate biogeographic and ecological analyses.

  PublisherOA PDFDOI

• Evidence for Low Dissolved Silica in mid-Mesozoic Oceans

  American Journal of Science · 2025-01-08 · 4 citations

  articleOpen access

  The geologic history of dissolved silica concentration in the ocean (DSi) is central to understanding the evolution of silica biomineralization, the interactions between the global carbon and silicon cycles, and their combined role controlling global climate over geologic time. However, the silica cycle in the geologic past is under-constrained, especially during major mass extinction events that impacted biosilicifiers and were associated with dramatic climate change. We measured the silicon isotope ratios (δ 30 Si) of 76 sponge spicules from the Panthalassic Ocean spanning the Triassic–Jurassic boundary (ca. 201 Ma) to constrain DSi concentrations during the mid-Mesozoic. Spicule measurements have mean δ 30 Si values of –0.25‰ ± 0.99‰. Our data, combined with constraints on seawater δ 30 Si from coeval radiolarians, suggest that mid-Mesozoic DSi was between 20–100 µM, a similar range to the modern ocean. Our results support increasing evidence that by the Mesozoic DSi had already decreased by orders of magnitude relative to the Precambrian. These results imply that radiolarians and sponges were drawing down DSi prior to diatom ecological dominance. Increasing sponge δ 30 Si values across the Triassic–Jurassic boundary, coupled with modeling evidence and previous palaeoecological observations, support that warming, increased weathering, and Si delivery before the end-Triassic extinction may have facilitated sponge expansion during the extinction recovery interval.

  PublisherOA PDFDOI

• Ichnology of the Permian-Triassic Mass Extinction in China

  2025-01-01 · 2 citations

  bookOpen access
  PublisherOA PDFDOI

• Introduction

  2025-01-01

  book-chapter
  PublisherDOI

• Systematic Ichnology and Fossil Illustrations

  2025-01-01

  book-chapter
  PublisherDOI

• The Stratigraphical Distributions and Paleoenvironmental Interpretations of the Ichnofossil-Bearing Strata

  2025-01-01

  book-chapter
  PublisherDOI

• MANAGING THE CURRENT MASS EXTINCTION: TIME IS THE ESSENCE

  Palaios · 2025-09-25

  article1st authorCorresponding
  PublisherDOI

• Implications for the Biotic Recovery Following the P-Tr Mass Extinction

  2025-01-01

  book-chapter
  PublisherDOI

Recent grants

• Workshop Proposal for Deep Time Earth-Life Observatories (DETELOs)

  NSF · $43k · 2010–2011

Frequent coauthors

• Wolfgang Kiessling

  180 shared

• Mark E. Patzkowsky

  Pennsylvania State University

  177 shared

• Michael Foote

  University of Chicago

  177 shared

• Martin Aberhan

  Museum für Naturkunde

  177 shared

• Matthew E. Clapham

  Planetary Science Institute

  141 shared

• Adam Tomášových

  Earth Science Institute of the Slovak Academy of Sciences

  128 shared

• Shanan E. Peters

  University of Wisconsin–Madison

  128 shared

• Stephen Q. Dornbos

  University of Wisconsin–Milwaukee

  123 shared

Awards & honors

• William H. Twenhofel Medal for Outstanding Contributions to…
• Paleontological Society Medal, 2019
• Honorary Member, Pacific Section SEPM Society for Sedimentar…
• Fellow, The Paleontological Society, 2007
• American Association for the Advancement of Science Fellow,…