Verification on the Evolutionary Pattern of Permo-Carboniferous Fusulinid Fauna In South China

Finding out the evolutionary pattern of biological faunas in the geological history is one of the most important and exciting parts in paleontological research. Based on detailed paleontological work on fusulinid specimens from the Moscovian to Early Kungurian strata in the Zongdi Section, Guizhou Province, South China, statistical analyses are carried out to testify the early results on the Permo-Carboniferous fusulinid evolutionary pattern in South China.

As the results of systematic study, 429 species belonging to 35 genera have been identified from 2676 specimens. To validate the change of the fusulinid genus and species diversities in the Zongdi Section, several biodiversity indices, such as the Margalef's richness index, the Shannon-Wiener richness index, and a statistical test by the rarefaction analysis, have been applied to uncover the evolutionary pattern. The present results showed consistence with conclusions of early researches on fusulinid diversity pattern in South China, which include:

1) Species diversity of the fusulinid fauna in the Zongdi Section increased significantly since the Triticites hobblensis zone in the Gzhelian, Late Carboniferous and quickly reached the maximum value in the Sphaeroschwagerina subrotunda zone of the Sakmarian, Early Permian.

2) Two turnover events occurred during the diversification of the fusulinid fauna in the Zongdi Section from Carboniferous to Permian. In the Kasimovian to Gzhelian, with the slow decline of the species number of the Fusulinidae, that of Schwagerinidae dramatically increased, leading to the result that the Schwagerininae finally became the major part of fusulinid fauna, which was Fusulinidae in the Moscovian. In the Late Sakmarian, the species number of Pseudoschwagerininae and Schwagerininae rapidly reduced; meanwhile the Misellininae, a phylogenetic branch of Verbeekinacea, started to appear and slowly diversified, and finally Verbeekinacea began to dominate the fusulinid fauna in Kungurian.