Carboniferous-Permian rugose coral Cyathaxonia faunas in China

Abstract

The Cyathaxonia faunas are widely distributed in the Carboniferous and Permian strata in China. The fauna in China contains 12 families and 40 genera, and can be recognized as three episodes from Early Carboniferous to the end-Permian in terms of their occurrence and composition: 1) Mississippian; 2) Pennsylvanian-Early Permian; 3) Middle Permian-Late Permian. They were relatively abundant in episodes 1 and 2. A decrease of family Antiphyllidae and an increase of family Hapsiphyllidae can be observed from Early Carboniferous to the end-Permian. Two case studies are given to illustrate the bio-facies of the Cyathaxonia faunas, which are from the Mississippian of Baoshan, West Yunnan and the Mississippian of Chaohu, South Anhui. In both areas, Cyathaxonia faunas occur just below the large dissepimented solitary and compound coral assemblages in a continuous sequence in a single section, which implies that the occurrence of these small, non-dissepimented solitary corals is not strictly related with Gondwanan or Peri-gondwanan cold water environment, but might be controlled by such benthic conditions as deeper, mud-rich, quieter, and darker sedimentary environments.