 It was commonly believed that marine ecosystems did not recover their full diversity until 5 to 10 million years following the mass extinction, and that marine reptiles recovered more slowly from the extinction than other lineages.However, the discovery of multiple diverse faunas of marine reptiles occurring in the Early Triassic — including "Cartorhynchus" — subsequently showed that this was not the case.In particular, it appears that ichthyosauriforms first appeared during the Spathian substage of the Olenekian stage and quickly attained high functional diversity in the first million years of their evolution.