华南早中二叠世类分异度变化过程的对比研究  

DIVERSITY CHANGES OF EARLY AND MIDDLE PERMIAN FUSULINACEAN FAUNA IN SOUTH CHINA

作　　者：杨湘宁[1] 史宇坤[1] 朱李鸣[1] 殷小龙[1] 

机构地区：[1]南京大学地球科学系,南京210093

出　　处：《古生物学报》2003年第4期517-524,共8页Acta Palaeontologica Sinica

基　　金：国家自然科学基金 ( 4 0 0 72 0 0 8);国家重点基础研究发展规划项目 (G2 0 0 0 0 7770 4)资助项目

摘　　要：根据复合标准剖面的数据 ,对华南早—中二叠世类动物群属种分异度的变化过程进行了研究 ,分析了早、中二叠世动物群属种首现及末现速率的差异。研究结果表明 ,类动物群属级分异度经历了两次快速上升 ,一次明显下降 ,在早、中二叠世出现两个相对独立的高峰 ,但总体上表现出持续上升趋势 ,并在中二叠世中期达到最大。早二叠世期间属级分异度的短暂下降主要与类动物本身的演化趋势有关 ,是动物群属级分类单元更替的结果。物种分异度在二叠纪初急剧增长 ,至早二叠世Sakmarian期已达到整个早—中二叠世的顶峰。早二叠世的动物群更替事件对物种分异度具有显著影响 ,并导致物种分异度随后总体呈下降趋势 ,中二叠世开始物种数虽有所上升 ,但始终未能恢复到早二叠世鼎盛时期的水平。早二叠世是类动物稳定发展时期 ,动物群中属种首现的总数及速率明显大于中二叠世 ,属种更替也更为频繁。中二叠世中期开始 ,类动物群属种分异度同时呈现急剧下降的趋势 ,但是 ,早、中二叠世华南类动物群中属种末现速率却并无明显差异 ,表明造成晚期古生代稳定生态系统崩溃的环境变化对类动物的成种速率有较大的影响 。Based on data from the composite standard section (CSS), a detailed investigation has been conducted to study genus and species diversity changes of the Early to Middle Permian fusulinacean fauna in South China. The percentages of genera and species first and last occurrence in the fauna were also compared to evaluate the differences in evolutionary rates between the Early and Middle Permian fusulinacean faunas. The results of analyses have shown that the curve of genus diversity comprises two peaks in the Early Permian and the early Middle Permian separated by a decline in the later Early Permian (Text fig. 1). Nevertheless, the number of genera displayed an overall trend of increase from the Early Permian towards the early Middle Permian and reached the highest diversity in the mid Middle Permian. The decline of genus diversity in the later Early Permian was caused by fauna turnover at the generic level related to the evolutionary stages of fusulinaceans. Analysis has also revealed that the species diversity increased dramatically since the beginning of the Early Permian and soon reached the highest level in the Sakmarian for the whole Early and Middle Permian in South China (Text fig. 3). However, the later Early Permian fauna turnover had a much severe impact at the specific level, which resulted in a remarkable loss of species in the fauna and kept the species diversity at a relatively low level for rest of the Early Permian. Although the number of species began to increase in the early Middle Permian, it had never been recovered to the same level in the Early Permian. Study on percentages of genera and species first or last occurrence in the fusulinacean fauna demonstrated that the Early Permian fauna possessed higher rates of first occurrence at both the generic and specific levels than the Middle Permian fauna, but their rates of last occurrence were similar to each other. These may further suggest that the fusulinaceans had experienced a stable evolutionary stage in the Early Permian characterized by

关 键 词：分异度 二叠纪 华南 筵类 无脊椎动物 

分 类 号：Q915[天文地球—古生物学与地层学]