The Ediacaran Biotas in Space and Time1
The Ediacaran Biotas in Space and Time1
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DOI：
10.1093/icb/43.1.104
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发表时间：
2003-02
期刊：
影响因子：
--
通讯作者：
B. Waggoner
中科院分区：
文献类型：
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作者：
B. Waggoner
摘要“埃迪卡拉纪生物”先于后生动物的寒武纪辐射并与之重叠，其中包括许多化石，经过50多年的研究，它们的系统位置仍然存在争议。从一个充满怪人的生物群中似乎学不到什么特别有用的东西。然而，分析埃迪卡拉生物体在时间和空间上的分布可以在不必猜测生物体的系统位置的情况下进行。将这些结果与古构造、古环境参数和各种组合的年龄数据结合起来，可以揭示埃迪卡拉纪生物的起源、生态甚至系统位置。Edemism简约分析(PAE)证实了早期将埃迪卡拉纪生物群划分为三个主要组合的研究：Avalon、White Sea和Nama组合。现有的辐射和地层学数据表明，阿瓦隆是最古老的，白海是第二古老的，纳玛延伸到寒武纪的底部。与“双边”和管状分类群相比，“叶状”埃迪卡拉分类群，以及程度较小的“水母类”，共同显示出明显更长的地层范围，更广泛的地理和古环境范围，以及更少的地域性。几乎所有管状埃迪卡拉生物似乎都局限于赤道地区，而其他埃迪卡拉生物表现出微弱的纬度多样性梯度或没有纬度多样性梯度。我的结论是，埃迪卡拉生物对各种环境参数表现出不同的反应范围。没有像过去经常做的那样，将它们全部归类为拥有单一的身体计划和生活模式的基础。
Abstract The “Ediacaran organisms,” which preceded and overlapped the Cambrian radiation of metazoans, include many fossils whose systematic positions remain contentious after over fifty years of study. It might seem that nothing particularly useful can be learned from a biota full of oddballs. However, analyses of the distribution of the Ediacaran organisms in time and space can be carried out without having to guess at the systematic position of the organisms. Combining these results with data on paleotectonics, paleoenvironmental parameters, and the ages of various assemblages sheds light on the origins, ecology, and even the systematic positions of the Ediacaran organisms. Parsimony Analysis of Endemism (PAE) confirms earlier studies in grouping Ediacaran biotas into three major clusters: the Avalon, White Sea, and Nama Assemblages. The available radiometric and stratigraphic data suggest that the Avalon is the oldest, the White Sea is next oldest, and the Nama extends to the base of the Cambrian. The “frondlike” Ediacaran taxa, and to a lesser extent the “medusoids,” collectively show significantly longer stratigraphic ranges, broader geographical and paleoenvironmental ranges, and less provinciality than “bilaterian” and tubular taxa. Almost all tubular Ediacarans appear to be confined to equatorial areas, whereas other Ediacaran organisms show weak or no latitudinal diversity gradients. I conclude that the Ediacaran organisms show a diverse range of responses to various environmental parameters. There is no basis for classifying them all as having a single body plan and mode of life, as has often been done in the past.