Carnian (Late Triassic) conodont faunas from south-western China and their implications

Conodonts are important index fossils for supra‐regional correlation especially in the Triassic. However, early Carnian conodonts are comparatively poorly known in South China. In this study, conodont biostratigraphy and taxonomy are investigated at three sections in the provinces of Yunnan and Guizhou. Two genera and 23 species are identified, including 4 new species: Quadralella (Q.) postica sp. nov., Q. robusta sp. nov., Q. wignalli sp. nov. and Q. yongningensis sp. nov. Five conodont zones are recognized. They are, in ascending order, the Paragondolella foliata Zone, Q. polygnathiformis Zone, Q. praelindae Zone, Q. aff. auriformis Zone and Q. robusta Zone. Conodonts are reasonably diverse and abundant in the upper Zhuganpo Formation (Julian 1) but decrease sharply in both species richness and diversity towards the Wayao Formation (Julian 2 and younger). It is most likely that this change was caused by climate warming and marine anoxia during the Carnian Humid Episode.