Abstract The abundance, diversity and extinction of non-marine algae are controlled by changes in the physical and chemical environment and community structure of continental ecosystems. We review a range of non-marine algae commonly found within the Permian and Triassic strata of Gondwana and highlight and discuss the non-marine algal abundance anomalies recorded in the immediate aftermath of the end-Permian extinction interval (EPE; 252 Ma). We further review and contrast the marine and continental algal records of the global biotic crises within the Permian–Triassic interval. Specifically, we provide a case study of 17 species (in 13 genera) from the succession spanning the EPE in the Sydney Basin, eastern Australia. The affinities and ecological implications of these fossil-genera are summarised, and their global Permian–Triassic palaeogeographic and stratigraphic distributions are collated. Most of these fossil taxa have close extant algal relatives that are most common in freshwater, brackish or terrestrial conditions, and all have recognizable affinities to groups known to produce chemically stable biopolymers that favour their preservation over long geological intervals. However, these compounds (e.g., sporopollenin and algaenan) are not universal, so the fossil record is sparse for most algal groups, which hinders our understanding of their evolutionary histories. Owing partly to the high preservational potential of Zygnematophyceae, a clade of freshwater charophyte algae and sister group to land plants, this group has a particularly diverse and abundant Permian–Triassic fossil record in Gondwana. Finally, we review and contrast the marine and continental algal records of the global biotic crises within the Permian–Triassic interval. In continental settings, Permian algal assemblages were broadly uniform across most of southern and eastern Gondwana until the EPE; here, we propose the Peltacystia Microalgal Province to collectively describe these distinct and prolonged freshwater algal assemblages. In the immediate aftermath of the EPE, relative increases in non-marine algae have been consistently recorded, but the distributions of prominent taxa of Permian freshwater algae became severely contracted across Gondwana by the Early Triassic. We highlight the paucity of quantitative, high-resolution fossil evidence for this key group of primary producers during all biotic crises of the Permian and Triassic periods. This review provides a solid platform for further work interpreting abundance and diversity changes in non-marine algae across this pivotal interval in evolutionary history.

中文翻译：

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冈瓦纳二叠纪-三叠纪非海藻——分布、自然亲缘关系和生态意义

摘要 非海洋藻类的丰度、多样性和灭绝受到大陆生态系统理化环境和群落结构变化的控制。我们回顾了冈瓦纳二叠纪和三叠纪地层中常见的一系列非海洋藻类，并强调和讨论了在二叠纪末灭绝间隔（EPE；252 Ma）之后立即记录的非海洋藻类丰度异常。我们进一步审查和对比了二叠纪-三叠纪时期全球生物危机的海洋和大陆藻类记录。具体而言，我们提供了来自澳大利亚东部悉尼盆地 EPE 演替中的 17 个物种（13 个属）的案例研究。总结了这些化石属的亲和力和生态意义，并整理了它们的全球二叠纪-三叠纪古地理和地层分布。这些化石类群中的大多数都有近亲现存的藻类亲属，这些藻类在淡水、咸水或陆地条件下最常见，并且都与已知能产生化学稳定的生物聚合物的群体有着可识别的亲缘关系，这些生物聚合物有利于它们在很长的地质间隔内保存。然而，这些化合物（例如，孢粉素和藻聚糖）并不普遍，因此大多数藻类群的化石记录很少，这阻碍了我们对其进化历史的理解。部分由于 Zygnematophyceae（淡水轮藻的一个分支和陆生植物的姊妹群）具有很高的保存潜力，该群在冈瓦纳有特别多样和丰富的二叠纪-三叠纪化石记录。最后，我们回顾并对比了二叠纪-三叠纪时期全球生物危机的海洋和大陆藻类记录。在大陆环境中，在 EPE 之前，冈瓦纳大陆南部和东部大部分地区的二叠纪藻类群落大致一致；在这里，我们建议使用 Peltacystia 微藻省来共同描述这些独特且长期存在的淡水藻类组合。在 EPE 的直接后果中，非海洋藻类的相对增加一直被记录下来，但二叠纪淡水藻类的突出分类群的分布在早三叠世在整个冈瓦纳变得严重收缩。我们强调，在二叠纪和三叠纪所有生物危机期间，这一主要初级生产者群体缺乏定量、高分辨率的化石证据。