Cloudinids have long been considered the earliest biomineralizing metazoans, but their affinities have remained contentious and undetermined. Based on well-preserved ultrastructures of two taxa, we here propose new interpretations regarding both their extent of original biomineralization and their phylogenetic affinity. One of these taxa is a new cloudinid from Mongolia, Zuunia chimidtsereni gen. et sp. nov., which exhibits key characteristics of submicrometric kerogenous lamellae, plastic tube-wall deformation, and tube-wall delamination. Multiple carbonaceous lamellae are also discovered in Cloudina from Namibia and Paraguay, which we interpret to have originated from chitinous or collagenous fabrics. We deduce that these cloudinids were predominantly originally organic (chitinous or collagenous), and postmortem decay and taphonomic mineralization resulted in the formation of aragonite and/or calcite. Further, based on our ultrastructural characterization and other morphological similarities, we suggest that the cloudinids should most parsimoniously be assigned to annelids with originally organic tubes.

中文翻译：

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Ediacaran cloudinids的超微结构表明，不同的Thonomic历史和与非生物矿化的annelids的亲和力。

Cloudinids长期以来一直被认为是最早的生物矿化后生动物，但它们的亲和力仍然存在争议和不确定性。基于两个分类单元保存完好的超微结构，我们在此提出有关其原始生物矿化程度及其系统发生亲和力的新解释。这些类群之一是来自蒙古的Zuunia chimidtsereni gen的新云雾类。等。nov。展示了亚微米级干酪根薄片，塑料管壁变形和管壁分层的关键特征。在纳米比亚和巴拉圭的Cloudina中也发现了多个碳质薄片，我们认为这是由几丁质或胶原质纤维起源的。我们推断这些云雾素最初主要是有机的（几丁质或胶原质），死后腐烂和离子矿化导致文石和/或方解石的形成。此外，基于我们的超微结构特征和其他形态相似性，我们建议应最简约地将cloudinids分配给具有原始有机管的annelids。