Population structure of the oldest known macroscopic communities from Mistaken Point, Newfoundland

The presumed affinities of the Terminal Neoproterozoic Ediacara biota have been much debated. However, even in the absence of concrete evidence for phylogenetic affinity, numerical paleoecological approaches can be effectively used to make inferences about organismal biology, the nature of biotic interactions, and life history. Here, we examine the population structure of three Ediacaran rangeomorph taxa (Fractofusus, Beothukis, and Pectinofrons), and one non-rangeomorph taxon (Thectardis) across five fossil surfaces around the Avalon Peninsula, Newfoundland, through analysis of size-frequency distributions using Bayesian Information Criterion (BIC). Best-supported models resolve communities of all studied Ediacaran taxa at Mistaken Point as single cohorts with wide variance. This result is best explained in terms of a “continuous reproduction” model, whereby Ediacaran organisms reproduce aseasonally, so that multiple size modes are absent from preserved communities. Modern benthic inve...

新元古代末期埃迪卡拉生物群（Ediacara biota）的推定亲缘关系长期以来备受争议。即便缺乏系统发育亲缘关系的确凿证据，数值古生态学方法仍可被有效用于推断生物体生物学特性、生物相互作用的本质以及生活史。本研究针对纽芬兰阿瓦隆半岛周边5处化石露头，采用贝叶斯信息准则（Bayesian Information Criterion, BIC）分析体型频率分布，以此考察3种埃迪卡拉rangeomorph类群（rangeomorph）——Fractofusus、Beothukis与Pectinofrons，以及1种非rangeomorph类群（Thectardis）的种群结构。最优支持模型将误点（Mistaken Point）所有研究埃迪卡拉类群的群落解析为具有广泛变异的单一年龄群。该结果可通过"连续繁殖"模型得到最佳解释：埃迪卡拉生物以非季节性方式繁殖，因此保存下来的群落中不存在多个体型峰值。现代底栖无脊椎动