Yunnan Key Laboratory for Palaeobiology, Institute of Palaeontology, Yunnan University, Kunming, China.
MEC International Joint Laboratory for Palaeobiology and Palaeoenvironment, Institute of Palaeontology, Yunnan University, Kunming, China.
Sci Rep. 2022 Mar 9;12(1):3852. doi: 10.1038/s41598-022-07822-z.
The Early Ordovician is a key interval for our understanding of the evolution of life on Earth as it lays at the transition between the Cambrian Explosion and the Ordovician Radiation and because the fossil record of the late Cambrian is scarce. In this study, assembly processes of Early Ordovician trilobite and echinoderm communities from the Central Anti-Atlas (Morocco), the Montagne Noire (France), and the Cordillera Oriental (Argentina) are explored. The results show that dispersal increased diachronically in trilobite communities during the Early Ordovician. Dispersal did not increase for echinoderms. Dispersal was most probably proximally triggered by the planktic revolution, the fall in seawater temperatures, changes in oceanic circulation, with an overall control by tectonic frameworks and phylogenetic constraints. The diachronous increase in dispersal within trilobite communities in the Early Ordovician highlights the complexity of ecosystem structuring during the early stages of the Ordovician Radiation. As Early Ordovician regional dispersal was followed by well-documented continental dispersal in the Middle/Late Ordovician, it is possible to consider that alongside a global increase in taxonomic richness, the Ordovician Radiation is also characterized by a gradual increase in dispersal.
早奥陶世是理解地球上生命进化的关键时期，因为它处于寒武纪大爆发和奥陶纪辐射之间，而且晚寒武纪的化石记录很少。本研究探讨了来自摩洛哥中央阿特拉斯山脉、法国 Montagne Noire 和阿根廷 Cordillera Oriental 的早奥陶世三叶虫和棘皮动物群落的组装过程。结果表明，早奥陶世三叶虫群落的扩散随时间推移而增加。棘皮动物的扩散没有增加。扩散很可能是由浮游生物革命、海水温度下降、海洋环流变化、构造框架和系统发育限制等因素近端触发的。早奥陶世三叶虫群落中扩散的时变增加突出了奥陶纪辐射早期生态系统结构的复杂性。由于早奥陶世的区域扩散随后在中/晚奥陶世有记录的大陆扩散，因此可以认为，除了分类群丰富度的全球增加外，奥陶纪辐射还以扩散的逐渐增加为特征。
