Trace fossils from the Ediacaran–Cambrian in southeastern margin of North China and their implications for the Cambrian Explosion

The Cambrian Explosion represents one of the most important evolutionary events in Earth history. Trace fossils play a crucial role in documenting the trend of increasing morphological complexity and taxonomic diversity during the Ediacaran—Cambrian transition. New ichnological data from the terminal Ediacaran Dongpo Formation and Cambrian Series 2 Xinji Formation in southwest Henan Province, North China, record evolutionary innovations in shallow-marine communities during the Cambrian Explosion. One ichnogenus and one ichnospecies have been recognized from the Dongpo Formation, and 8 ichnogenera and 16 ichnospecies from the Xinji Formation. Multidimensional cubes of ecospace utilization and ecosystem engineering show a positive correlation between these proxies and ichnodiversity and ichnodisparity, with increased values during the Cambrian. The occurrence of Didymaulichnus, Treptichnus, and Psammichnites in this interval indicates enhanced ability for sediment modification during biogenic reworking. The ichnofauna in the Cambrian Series 2 Xinji Formation records the second phase of ichnodiversity increase during the Cambrian Explosion.