Drepanoistodontid conodonts from the Early Ordovician Honghuayuan Formation of Guizhou, South China
Contents
Abstract
Four drepanoistodontid species, Drepanoistodus sp. cf. D. nowlani, Paltodus sp. cf. P. subaequalis, Paltodus sp. A, and Paroistodus sp. are described and illustrated from the Lower Ordovician Honghuayuan Formation in Guizhou, South China. Drepanoistodus sp. cf. D. nowlani is abundant throughout the formation whereas the other three species occur rarely. Presence of Paltodus sp. cf. P. subaequalis at the base of the Honghuayuan Formation at its type locality indicates a late Tremadocian age for this level. Specimens from Sweden of the two Lower Ordovician index species Paltodus deltifer and Paroistodus proteus, as well as three species of Drepanoistodus (D. forceps, D. basiovalis and D. sp. cf. D. suberectus), are also illustrated. Comparison with the Swedish material reveals that previously reported occurrences of P. deltifer and P. proteus in South China were either mis-identified or based on ambiguous data.
