Age and distribution of the Late Devonian brachiopod genus DzieduszyckiaSiemiradzki, 1909 in southern China

Conodont biostratigraphical work was done at four sections recently found with occurrence of the rhynchonellide brachiopod genus, DzieduszyckiaSiemiradzki, in southern Guangxi and in the border area between Dushan County of Guizhou and Nandan County of Guangxi, South China. These sections represent two different types of facies, i.e., carbonate platform and intraplatform basin. The conodont analysis reveals that this genus occurs in the Upper triangularisZone and the Middle crepidaZone at the Dazhai Section, through the Lower to Upper crepidazones at Dalong, and is restricted within the Upper rhomboideaZone at the two intraplatform basin sections (Changtang and Duli). This result demonstrates that the occurrence of these peculiar rhynchonellide brachiopods in South China, regardless of the depositional environments, is within the Lower Famennian instead of the previously suggested Upper Famennian. Furthermore, this brachiopod genus in South China began to inhabit on the carbonate platform almost since the beginning of the Famennian and did not extend to the intraplatform basin facies until the late Early Famennian.