MACROSCOPIC CARBONACEOUS COMPRESSIONS IN A TERMINAL PROTEROZOIC SHALE: A SYSTEMATIC REASSESSMENT OF THE MIAOHE BIOTA, SOUTH CHINA
MACROSCOPIC CARBONACEOUS COMPRESSIONS IN A TERMINAL PROTEROZOIC SHALE: A SYSTEMATIC REASSESSMENT OF THE MIAOHE BIOTA, SOUTH CHINA
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DOI：
10.1017/s0022336000041743
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发表时间：
2002-03
影响因子：
2.4
通讯作者：
S. Xiao;Xunlai Yuan;M. Steiner;A. Knoll
中科院分区：
文献类型：
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作者：
S. Xiao;Xunlai Yuan;M. Steiner;A. Knoll
摘要：三峡苗河地区陡山沱组上段（约555 ~ 590 Ma）页岩中的碳质压缩化石为研究末元古代生物提供了一个难得的伯格斯-页岩型地层学窗口。从苗河页岩中发现的大化石有100多种，但在对已发表的和新发现的材料的研究中，我们只认识到大约20个不同的分类群，包括Aggregatosphaera miaoheensis new gen和sp.这些化石大多可以明确地解释为群体原核生物或多细胞藻类。系统发育衍生的囊胞绿藻似乎存在，与红藻和褐藻相似的有规律的分岔菌体也存在。至少有五个物种被先前的工作者解释为后生动物。其中，小原孔虫和纹状Calyptrina最像动物遗骸；其中一种或两种都可能是刺胞动物的有机鞘，尽管不能排除P. minor的藻类起源。尽管保存得很好，但庙河化石群中没有肉眼可见的化石，不能有把握地解释为双边动物。结合其他新元古代晚期和早寒武纪的体化石和迹化石，陡山沱组组合支持了双边门内体平面多样化主要是寒武纪事件的观点。
Abstract Carbonaceous compression fossils in shales of the uppermost Doushantuo Formation (ca. 555–590 Ma) at Miaohe in the Yangtze Gorges area provide a rare Burgess-Shale-type taphonomic window on terminal Proterozoic biology. More than 100 macrofossil species have been described from Miaohe shales, but in an examination of published and new materials, we recognize only about twenty distinct taxa, including Aggregatosphaera miaoheensis new gen. and sp. Most of these fossils can be interpreted unambiguously as colonial prokaryotes or multicellular algae. Phylogenetically derived coenocytic green algae appear to be present, as do regularly bifurcating thalli comparable to red and brown algae. At least five species have been interpreted as metazoans by previous workers. Of these, Protoconites minor and Calyptrina striata most closely resemble animal remains; either or both could be the organic sheaths of cnidarian scyphopolyps, although an algal origin cannot be ruled out for P. minor. Despite exceptional preservation, the Miaohe assemblage contains no macroscopic fossils that can be interpreted with confidence as bilaterian animals. In combination with other late Neoproterozoic and Early Cambrian body fossils and trace fossils, the Doushantuo assemblage supports the view that body-plan diversification within bilaterian phyla was largely a Cambrian event.