Zhan Renbin, Jin Jisuo
State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China.
Department of Earth Sciences, Western University, London, Ontario, Canada.
Integr Zool. 2014 Mar;9(2):121-140. doi: 10.1111/1749-4877.12052.
Paleobiogeographic patterns of the brachiopod faunas before and during the first radiation of the Great Ordovician Biodiversification Event (GOBE) in South China at 6 different localities from the upper Jiangnan Slope to the vast area of the Upper Yangtze Platform show several interesting features. First, the initial brachiopod diversity acme was accompanied by both high origination and extinction rates. Second, no significant changes took place in the taxonomic composition and paleobiogeographic pattern of the brachiopod fauna during the radiation at 5 of the 6 localities studied except the near shore locality, where the first brachiopod radiation was much later than at other localities and was marked by a dramatic increase in endemic constituents. Third, orthides were the predominant brachiopod group during the radiation, and regional brachiopod taxa played a significant role in defining the paleobiogeographic pattern of the radiation. Fourth, the first brachiopod radiation was associated with 3 major pulses of onshore migration from the upper Jiangnan Slope through the central Upper Yangtze Platform to the near shore settings of the platform, with the middle pulse being the most significant. Finally, paleogeographic dispersal took place in both onshore and offshore directions, although the onshore expansion was more prominent; several key brachiopods, such as Paralenorthis, Nocturnellia, Protoskenidioides, Nereidella, Euorthisina and Yangtzeella, first appeared on the upper Jiangnan Slope and later formed distinct, and taxonomically diverse, communities on the Upper Yangtze Platform. The paleogeographic dispersal of brachiopods is considered to be closely related to the tectonic evolution of the Qianzhong Arch.
在华南地区，从江南斜坡上部到上扬子地台广大区域的6个不同地点，展示了奥陶纪大生物多样化事件（GOBE）首次辐射之前和期间腕足动物群的古生物地理格局，呈现出几个有趣的特征。首先，最初的腕足动物多样性高峰伴随着高起源率和灭绝率。其次，在所研究的6个地点中的5个，除了近岸地点外，腕足动物群的分类组成和古生物地理格局在辐射期间没有发生显著变化。在近岸地点，首次腕足动物辐射比其他地点晚得多，其特征是特有成分急剧增加。第三，正形贝类是辐射期间的主要腕足动物类群，区域腕足动物分类单元在定义辐射的古生物地理格局中发挥了重要作用。第四，首次腕足动物辐射与从江南斜坡上部经上扬子地台中部到地台近岸环境的3次主要向岸迁移脉冲有关，其中中间脉冲最为显著。最后，尽管向岸扩张更为突出，但古地理扩散在向岸和离岸方向都有发生；几个关键的腕足动物，如副线正形贝、夜形贝、原斯肯德贝、沙蚕贝、真正形贝和扬子贝，首先出现在江南斜坡上部，后来在上扬子地台形成了不同的、分类多样的群落。腕足动物的古地理扩散被认为与黔中隆起的构造演化密切相关。
