Differences between subfamilies in diversification process of the Early and Middle Permian fusulinid fauna in South China

Based on the fusulinid occurrence records from a computerized database of stratigraphic distribution, statistic comparisons have been conducted to disclose the differences among six subfamilies (constituting the major part of the fusulinid fauna) in generic and specific diversities, rates of speciation and extinction, and changes in the rates and others during the diversification process of the fusulinid fauna in Early and Middle Permian in South China. Our results reveal that: (1) significant differences exist in the diversification pattern of different taxa and (2) the rates of speciation and extinction in Schwagerininae are statistically higher than those in the others. Furthermore, the high rate of speciation in Schwagerininae contributed to the higher rate of diversification of the fusulinid fauna in Early Permian, whereas the lower rate of diversification in the Middle Permian has resulted from the ubiquitous low rates of speciation in all major taxa in the fauna, such as Schwagerininae, Neoschwagerininae, Verbeekininae, Sumatrininae, and Misellininae.