Anomalously diverse Early Triassic ichnofossil assemblages in northwest Pangea: A case for a shallow-marine habitable zone

Early Triassic trace fossil assemblages from the northwest margin of Pangea record a diverse suite of postextinction infauna. These ichnofossil assemblages occurred within well-oxygenated,shallow-marine refuges in a Panthalassa Ocean otherwise characterized by widespread anoxia. We propose an environmentally controlled model for their distribution, in which wave aeration, enhanced by frequent storms, gave rise to an optimal zone for benthic colonization. Within this habitable zone extinction pressures were ameliorated and post extinction recovery duration was minimized.