Rapid macrobenthic diversification and stabilization after the end-Cretaceous mass extinction event

Abstract

Previous ichnological analysis at the Chicxulub impact crater, Yucatán Peninsula, México (International Ocean Discovery Program [IODP]/International Continental Scientific Drilling Program [ICDP] Site M0077), showed a surprisingly rapid initial tracemaker community recovery after the end-Cretaceous (Cretaceous-Paleogene [K-Pg]) mass extinction event. Here, we found that full recovery was also rapid, with the establishment of a well-developed tiered community within ~700 k.y. Several stages of recovery were observed, with distinct phases of stabilization and diversification, ending in the development of a trace fossil assemblage mainly consisting of abundant Zoophycos, Chondrites, and Planolites, assigned to the Zoophycos ichnofacies. The increase in diversity is associated with higher abundance, larger forms, and a deeper and more complex tiering structure. Such rapid recovery suggests that favorable paleoenvironmental conditions were quickly reestablished within the impact basin, enabling colonization of the substrate. Comparison with the end-Permian extinction reveals similarities during recovery, yet postextinction recovery was significantly faster after the K-Pg event. The rapid recovery has significant implications for the evolution of macrobenthic biota after the K-Pg event. Our results have relevance in understanding how communities recovered after the K-Pg impact and how this event differed from other mass extinction events.