Work

Silent past: Biogeographic gaps in the Cenozoic fossil archive

Year: 2025

Type: article

Abstract: Exposed sedimentary rocks—key to preserving fossil evidence—are unevenly distributed across space and time, limiting our understanding of past climates and ecosystems. In this study, we quantified the extent of "lost" areas where sedimentary layers are no longer exposed, analysing gaps by climate zone and geological time. Using Chorlton’s global geological map, we reconstructed the distribution of exposed sedimentary rocks at their time of deposition and linked them with palaeoclimate data from the HadCM3 model, classified using the Köppen-Geiger system. We compared this with fossil occurrence data from the Paleobiology Database (PBDB) to assess discrepancies between preserved rock distributions and recorded fossils. Our results reveal that over 72% of past continental areas are missing from the current sedimentary record. Tropical and arid zones are over-represented, while temperate, cold, and polar zones are under-represented. This indicates a significant preservation bias, potentially skewing our understanding of evolution by favouring organisms from certain climates. These findings highlight that major portions of Earth’s biological history are permanently lost due to preservation limitations—not merely from lack of sampling—emphasising the need to account for these biases in studies of biodiversity, macroevolution, and species’ responses to climate change.

Source: Palaeogeography Palaeoclimatology Palaeoecology

DOI: 10.1016/j.palaeo.2025.113296