论文部分内容阅读
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 ,持续的低成种速率是导致中二叠世类动物属种分异度下降的内在因素
Based on the data from the composite standard profiles, the variation of the taxonomic diversity of the early-middle Permian fauna in South China was studied. The first and last occurrence rates of the early and middle Permian fauna were analyzed difference. The results show that the taxonomic level of the taxon has experienced two rapid increases, a significant decline in the early and middle Permian two relatively independent peaks, but generally showed a rising trend in the Mid-Middle Perm reached the maximum. The short-term decline of genus-level divergence during the Early Permian period was mainly related to the evolutionary tendency of the ichthyas and was the result of the replacement of taxonomic taxa in the fauna. Species diversity increased rapidly at the beginning of the Permian, reaching the peak of the whole early-middle Permian until the Early Permian Sakmarian period. The fauna alteration in the Early Permian had a significant effect on species differentiation and subsequently led to a general downward trend in species diversity. Although the number of species started to increase in the middle Permian, it never recovered to the second The heyday of the fold. The Early Permian is a period of stable development of the claw, and the total number and rate of the first occurrence of the genus in the fauna is obviously greater than that of the Middle Permian. The genus alternation is also more frequent. From the middle of Middle Permian, the species diversity of the tribe showed a sharp decline at the same time. However, there was no significant difference in the rates of the end species in the southern and southern Permian swamp fauna, suggesting that The environmental changes of the collapse of the stable Paleozoic ecosystems in late Paleozoic have a great influence on the species-forming rate of the beetles, and the continuous low-subsurface rate is the intrinsic factor leading to the decline of the species diversity of the Middle Permian claws