Fig. 1: Geological setting of the Longwangjing section.

A Location and regional geology of the Longwangjing section (red star). B Field view of the Longwangjing section, showing the Paleocene/Eocene boundary and the fossil bed location. C Primate fossil (Archicebus achilles)19. D Carbon isotope stratigraphy of total organic carbon (δ13CTOC) and carbonate (δ13Ccarb)16. The colored area demarcates the PETM interval, defined by a large negative carbon isotope excursion.