Preservation bias obscures gradual Ordovician reef evolution

Understanding major evolutionary transitions requires distinguishing true biological signals from preservation artifacts. Our research challenges conventional interpretations of the Great Ordovician Biodiversification Event in reef ecosystems by revealing how sea-level fluctuations created a misleading pattern. By correlating global sea-level changes with fossil occurrences across paleocontinents, we demonstrate that the apparent sudden emergence of diverse reef communities reflects improved preservation conditions rather than an evolutionary burst. Early reef-builders likely evolved gradually, but their record was masked by extensive erosion during a major regression. This result transforms our understanding of early reef ecology and demonstrates how taphonomic biases can generate illusory evolutionary patterns, thereby reframing the Cambrian Explosion and Ordovician Biodiversification as components of one extended diversification process.