The pink horizontal line shows the stratigraphic level of the end-Smithian biocrisis, coincident with a rapid increase in δ13Ccarb; the green horizontal line shows the first occurrence of Triassic marine reptiles. Helong. Fm.: Helongshan Formation; D. Fm.: Dongma’anshan Formation. The large silhouettes to the left of the lithology are marine reptiles; the small silhouettes to the left of the lithology (and one medium silhouette) are fish.