Abstract Benthic marine macroalgae or seaweeds are key ecological players in oceans today and have been since the Proterozoic. To date, however, morphological and evolutionary patterns for Precambrian macroalgae have been documented only in rather broad terms. To refine our understanding in this critical interval, we updated a dataset of Proterozoic to early Paleozoic noncalcified macroalgal fossils preserved as macroscopic carbonaceous compressions. The data were analyzed using non-parametric multidimensional scaling (NMDS) and functional-form group (FFG) approaches, in order to characterize morphological and ecological evolutionary patterns of these macroalgae. At the broadest scale, the results show progressive increases in thallus size, morphospace range, and aspects of ecological complexity such as canopy heights, surface area/volume ratios, and functional-form groups through time. These trends, however, are not always monotonous. In particular, significant increases in Proterozoic macroalgal morphological diversity and maximum size appear to have occurred in the Neoproterozoic (Tonian and Ediacaran periods, respectively). Analysis of Ediacaran macroalgal assemblages shows that macroalgae broadly follow the Ediacara-like fossil assemblages, with a significant drop in most studied metrics in the terminal Ediacaran Stage (∼ 550–539 Ma). The latter event occurs during the Kotlinian crisis experienced by Ediacara-type macro-organisms, highlighting the possibility that this extinction event during the Ediacaran-Cambrian transition affected both macroalgae and Ediacara-type macro-organisms. Our analysis also confirms an Ordovician increase in the morphological and ecological diversity of macroalgae.

中文翻译：

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穿越时空的海藻：元古代和早古生代底栖大型藻类的形态和生态分析

摘要 底栖海洋大型藻类或海藻是当今海洋中的关键生态参与者，自元古代以来一直存在。然而，迄今为止，前寒武纪大型藻类的形态和进化模式仅在相当广泛的术语中得到了记录。为了完善我们对这个关键间隔的理解，我们更新了元古代到早期古生代非钙化大型藻类化石的数据集，这些化石保存为宏观碳质压缩物。使用非参数多维尺度 (NMDS) 和功能形式组 (FFG) 方法分析数据，以表征这些大型藻类的形态和生态进化模式。在最广泛的范围内，结果显示叶绿体大小、形态空间范围和生态复杂性方面（例如冠层高度、表面积/体积比、和功能组随着时间的推移。然而，这些趋势并不总是单调的。特别是，新元古代（分别是托尼安和埃迪卡拉纪）似乎发生了元古代大型藻类形态多样性和最大尺寸的显着增加。埃迪卡拉纪大型藻类组合的分析表明，大型藻类大致遵循类埃迪卡拉纪化石组合，大多数研究的指标在埃迪卡拉纪末期（~550-539 Ma）显着下降。后一事件发生在埃迪卡拉型宏观生物经历的科特林危机期间，突出了埃迪卡拉纪-寒武纪过渡期间的这种灭绝事件影响大型藻类和埃迪卡拉型宏观生物的可能性。