Data from: Relating Ediacaran fronds

Ediacaran fronds are key components of terminal-Proterozoic ecosystems. They represent one of the most widespread and common body forms ranging across all major Ediacaran fossil localities and time slices postdating the Gaskiers glaciation, but uncertainty over their phylogenetic affinities has led to uncertainty over issues of homology and functional morphology between and within organisms displaying this ecomorphology. Here we present the first large-scale, multigroup cladistic analysis of Ediacaran organisms, sampling 20 ingroup taxa with previously asserted affinities to the Arboreomorpha, Erniettomorpha, and Rangeomorpha. Using a newly derived morphological character matrix that incorporates multiple axes of potential phylogenetically informative data, including architectural, developmental, and structural qualities, we seek to illuminate the evolutionary history of these organisms. We find strong support for existing classification schema and devise apomorphy-based definitions for each of the three frondose clades examined here. Through a rigorous cladistic framework it is possible to discern the pattern of evolution within and between these clades, including the identification of homoplasies and functional constraints. This work both validates earlier studies of Ediacaran groups and accentuates instances in which previous assumptions of their natural history are uninformative.埃迪卡拉纪（Ediacaran）叶状体是新元古代末期生态系统的关键组成部分。它们是分布最广泛、最常见的躯体形态类群之一，见于加斯基亚冰期之后所有主要埃迪卡拉纪化石产地与地质时段，但由于其系统发育亲缘关系尚不明确，导致具有这类生态形态的生物类群内部及类群间的同源性与功能形态学问题存在争议。本文首次针对埃迪卡拉纪生物开展大规模多类群分支系统学分析，选取20个内群分类单元，这些类群此前被认为与树形类（Arboreomorpha）、埃尼耶塔类（Erniettomorpha）以及Rangeomorpha类具有亲缘关系。我们采用全新构建的形态学特征矩阵，纳入了多维度潜在系统发育信息数据，包括构造、发育与结构属性，旨在阐明这类生物的演化历史。研究结果为现有分类方案提供了强有力的支持，同时为本文所分析的三个叶状演化支分别制定了基于衍征的定义。通过严谨的分支系统学框架，我们能够厘清这些演化支内部及类群间的演化模式，包括识别趋同演化现象与功能约束因素。本研究既验证了此前针对埃迪卡拉纪类群的相关研究，同时也凸显出此前对其演化历史的部分假设缺乏实际参考价值。