Phosphatized microfossils from the Miaohe Member of South China and their implications for the terminal Ediacaran biodiversity decline
Phosphatized microfossils from the Miaohe Member of South China and their implications for the terminal Ediacaran biodiversity decline
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DOI：
10.1016/j.precamres.2023.107001
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发表时间：
2023-05
影响因子：
3.8
通讯作者：
Qin Ye;Z. An;Yang Yu;Ze Zhou;jun Hu;J. Tong;S. Xiao
中科院分区：
文献类型：
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作者：
Qin Ye;Z. An;Yang Yu;Ze Zhou;jun Hu;J. Tong;S. Xiao
华南上埃迪卡拉统庙河段（~ 550 Ma）以保存完好的宏观碳质压缩化石（即庙河生物群）而闻名，这些化石对了解埃迪卡拉末期的海洋生态和环境具有重要意义。然而，作为海洋生态系统重要生物组成部分的微生物却鲜有文献记载，且主要局限于华南和世界各地庙河段及等效地层的简单层圈和细丝。本文报道了湖北马溪剖面庙河段磷岩、硅质磷岩结核和磷矿带中细胞保存的微化石组合。已鉴定出8属10个已命名种、4个未命名分类群和2个未命名分类群，包括几种多细胞藻类化石和各种球藻和丝状蓝藻。大量的球形化石在形态上类似于先前被解释为假定的后生动物胚胎的gasasphaera。这些微化石与先前在庙河段等效地层中发现的微化石一起，扩大了我们对寒武纪大爆发前海洋生态系统演化的认识。晚埃迪卡拉纪Maxi组合和早埃迪卡拉纪翁安生物群共用几个分类群，它们都是通过磷化作用保存下来的。值得注意的是，在Maxi组合中没有陡山沱组- pertatataka组-type acanthomorphs (dpa)，但在旺安生物群中却大量存在，这与dpa在埃迪卡拉纪晚期的减少一致，这可能导致了在Kotlin危机时期或埃迪卡拉纪最后1000万年中，埃迪卡拉生物群中大型软体生物的减少。
The upper Ediacaran Miaohe Member (∼550 Ma) in South China is well known for exceptionally preserved macroscopic carbonaceous compression fossils (i.e., the Miaohe biota) that are pivotal in understanding the marine ecology and environment during the terminal Ediacaran Period. However, micro-organisms, which are also important biotic components of marine ecosystems, are poorly documented and largely limited to simple leiospheres and filaments in the Miaohe Member and equivalent strata in South China and around the world. Here we report a moderately diverse assemblage of cellularly preserved microfossils from phosphorites and siliceous phosphorite nodules and bands of the Miaohe Member at the Maxi section, Hubei Province, South China. Ten named species of eight genera, four open nomenclatures, and two unnamed taxa have been identified, including several multicellular algal fossils and various coccoidal and filamentous cyanobacteria. Abundant spheroidal fossils are morphologically analogous toMegasphaera, which has previously been interpreted as a putative metazoan embryo. Together with previously described microfossils from equivalent strata of Miaohe Member, these microfossils expand our understanding of the evolution of marine ecosystems prior to the Cambrian explosion. The late Ediacaran Maxi assemblage and the early Ediacaran Weng’an biota, both preserved through phosphatization, share several taxa. Notably, Doushantuo-Pertatataka-type acanthomorphs (DPAs) are absent from the Maxi assemblage but abundant in the Weng’an biota, consistent with a late Ediacaran decline of DPAs, which may have ushered in the terminal Ediacaran decline of soft-bodied macro-organisms of the Ediacara biota during the Kotlin crisis or in the last 10 million years of the Ediacaran Period.