Rhipidognathid conodonts from the Early Ordovician Honghuayuan Formation of Guizhou, South China
The two oldest species of rhipidognathid conodonts, Rhipidognathus yichangensis (Ni, 1981) and Bergstroemognathus extensus (Graves and Ellison, 1941), are described and illustrated from the Early Ordovician Honghuayuan Formation of Guizhou, South China. Both species are interpreted as having a septimembrate apparatus. The form species Bergstroemognathus hubeiensis An in An et al., 1981 is regarded as a junior synonym of B. extensus. The multi-element species B. hubeiensis defined by An et al. (1985) includes elements belonging to both B. extensus and R. yichangensis, and hence can no longer be regarded as a valid species.