Data from: The Proterozoic record of eukaryotes

Proterozoic strata host evidence of global “Snowball Earth” glaciations, large perturbations to the carbon cycle, proposed changes in the redox state of oceans, the diversification of microscopic eukaryotes, and the rise of metazoans. Over the past half century, the number of fossils described from Proterozoic rocks has increased exponentially. These discoveries have occurred alongside an increased understanding of the Proterozoic Earth system and the geological context of fossil occurrences, including improved age constraints. However, the evaluation of relationships between Proterozoic environmental change and fossil diversity has been hampered by several factors, particularly lithological and taphonomic biases. Here we compile and analyze the current record of eukaryotic fossils in Proterozoic strata to assess the effect of biases and better constrain diversity through time. Our results show that mean within assemblage diversity increases through the Proterozoic Eon due to an increase in high diversity assemblages, and that this trend is robust to various external factors including lithology and paleogeographic location. In addition, assemblage composition changes dramatically through time. Most notably, robust recalcitrant taxa appear in the early Neoproterozoic Era, only to disappear by the beginning of the Ediacaran Period. Within assemblage diversity is significantly lower in the Cryogenian Period than in the preceding and following intervals, but the short duration of the nonglacial interlude and unusual depositional conditions may present additional biases. In general, large scale patterns of diversity are robust while smaller scale patterns are difficult to discern through the lens of lithological, taphonomic, and geographic variability.元古宙（Proterozoic）地层保存有全球「雪球地球（Snowball Earth）」冰期、碳循环剧烈扰动、海洋氧化还原状态变化假说、微观真核生物的演化分异以及后生动物兴起的相关证据。过去半个世纪以来，元古宙岩石中被描述的化石数量呈指数级增长。这些发现与学界对元古宙地球系统以及化石产出的地质背景（包括更为精准的年代约束）的认知提升同步推进。然而，评估元古宙环境变化与化石多样性之间的关联仍受到诸多因素阻碍，尤其是岩性偏差与埋藏学（taphonomic）偏差。本文汇编并分析了当前元古宙地层中的真核生物化石记录，以评估各类偏差的影响，并更为精准地约束地质时间尺度上的多样性变化轨迹。研究结果显示，元古宙时期的组合内平均多样性随时间推移不断提升，这一趋势源于高多样性组合的占比增加，且该趋势在岩性、古地理位置等各类外部因素影响下均保持稳健。此外，化石组合的组成随时间发生显著变化。最突出的是，难降解的稳健类群在新元古代（Neoproterozoic Era）早期出现，但在埃迪卡拉纪（Ediacaran Period）伊始便消失殆尽。成冰纪（Cryogenian Period）的组合内多样性显著低于其前后的地质时段，但无冰间歇期的持续时长较短以及特殊的沉积条件可能带来额外的偏差。总体而言，多样性的大尺度分布模式较为稳健，而受岩性、埋藏学以及地理变异的影响，小尺度的多样性模式难以被清晰辨识。