Data from: The Beothukis/Culmofrons problem and its bearing on Ediacaran macrofossil taxonomy: evidence from an exceptional new fossil locality

The late Ediacaran siliciclastic successions of eastern Newfoundland, Canada, are renowned for their fossils of soft-bodied macro-organisms, which may include some of the earliest animals. Despite the potential importance of such fossils for evolutionary understanding, the taxonomic framework within which Ediacaran macrofossils are described is not clearly defined. Rangeomorphs from a newly discovered fossil surface on the Bonavista Peninsula, Newfoundland, require us to reconsider contemporary use of morphological characters to distinguish between genera and species within Ediacaran taxa. The new surface exhibits remarkable preservational fidelity, resolving features smaller than 0.1 mm in dimension in both frondose and non-frondose taxa. Such preservation permits the recognition of rarely observed fourth- and fifth-order rangeomorph branching, offering unparalleled opportunities to investigate the fine-scale construction of rangeomorph taxa including Culmofrons plumosa Laflamme et al., 2012. Our observations enable resolution of taxonomic issues relating to rangeomorphs, specifically overlap between the diagnoses of the frondose genera Beothukis Brasier and Antcliffe, 2009 and Culmofrons. We propose a taxonomic framework for all Ediacaran macrofossils whereby gross architecture, the presence/absence of discrete morphological characters and consideration of growth programme are used to distinguish genera, whereas morphometric or continuous characters define taxa at the species level. On the basis of its morphological characters, Culmofrons plumosa is herein synonymized to a species (Beothukis plumosa comb. nov.) within the genus Beothukis. This discussion emphasizes the need to standardize the taxonomic approach used to describe Ediacaran macrofossil taxa at both the genus and species levels, and raises important considerations for future formulation of higher-level taxonomic groups.加拿大东部纽芬兰地区的晚埃迪卡拉纪硅质碎屑岩系，以产出可能包含早期动物类群的软躯体宏体生物化石而享誉学界。尽管这类化石对于演化研究具有潜在的重要价值，但埃迪卡拉纪大型宏体化石的分类学框架迄今仍未得到明确界定。产自纽芬兰博纳维斯塔半岛一处新发现化石露头的Rangeomorph类群（Rangeomorph），促使我们重新审视当前利用形态特征区分埃迪卡拉纪类群内属与种的研究范式。该新露头展现出极高的保存保真度，能够分辨叶状与非叶状类群中尺寸小于0.1毫米的微细结构。这种优异的保存状态使得我们能够识别此前罕有报道的四阶与五阶Rangeomorph分支结构，为研究包括*Culmofrons plumosa* Laflamme et al., 2012在内的Rangeomorph类群的精细构造提供了前所未有的契机。我们的观测结果得以解决与Rangeomorph类群相关的分类学争议，尤其是叶状属*Beothukis* Brasier and Antcliffe, 2009与*Culmofrons*的鉴别特征之间的重叠问题。我们提出适用于所有埃迪卡拉纪大型宏体化石的分类学框架：以整体构型、离散形态特征的有无以及生长发育程序作为属级区分依据，而以形态计量学或连续形态特征作为种级类群的界定标准。基于其形态特征，*Culmofrons plumosa*现被归为*Beothukis*属内的一个物种（*Beothukis plumosa* comb. nov.，新组合）。本讨论强调了标准化埃迪卡拉纪大型宏体化石属、种两级分类学描述方法的必要性，并为未来高阶分类群的建立提出了重要考量方向。