In southern Guizhou, South China, there are well-exposed shallow-water deposits of the Jiusi and Shangsi formations, which consist of platform limestones mixed with shales and sandstones. Conodonts, ancient tooth-like fossils, were found in the limestones and were dominated by two groups: the Cavusgnathus aff. Cav. unicornis and Clydagnathus windsorensis in the upper Jiusi Formation and the Cavusgnathus unicornis in the lowest Shangsi Formation. Vogelgnathus campbelli with small lateral denticles was found for the first time in Eastern Paleotethys. The Cavusgnathus unicornis is used as a marker for the regional Shangsian stage and correlated to other conodont zones marked by similar species in North America and Europe of middle Visean.

The typical Mississippian shallow-water deposits of the Jiusi and Shangsi formations are well exposed in the Yashui section in southern Guizhou, South China. The strata are composed mainly of platform limestones intercalated with shales and sandstones. Conodonts obtained from the limestones are dominated by two assemblages of cavusgnathids: the Cavusgnathus aff. Cav. unicornis and Clydagnathus windsorensis assemblage from the upper Jiusi Formation and the Cavusgnathus unicornis assemblage from the lowest Shangsi Formation. Vogelgnathus campbelli (Rexroad, 1957) is reported for the first time in Eastern Paleotethys and is characterized by small lateral denticles. The evolutionary first occurrence of Cavusgnathus unicornis Youngquist and Miller, 1949 is recognized as a marker for the regional Shangsian stage. This biostratigraphic datum is interpreted to be correlative with other shallow-water conodont zones marked by Cavusgnathus unicornis s.l. and similar species from North America and Europe.