Abstract The temporal and spatial distribution of Hirnantian brachiopod faunas are reviewed based on a new, comprehensive dataset from over 20 palaeoplates and terranes, a revised correlation scheme for Hirnantian strata and numerical methods including network analysis. There were two successive evolutionary faunas: 1. the widespread and diachronous Hirnantia Fauna related to the glacial acme in the early−mid Hirnantian, including shallow, deeper and deep-water communities that diversified in much more complicated environmental conditions than hitherto envisaged; and 2. the Edgewood-Cathay Fauna (new term) thrived during post-glacial, warmer, shallow-water regimes with both carbonate and siliciclastic facies from low latitudes in the late Hirnantian−early Rhuddanian. The two survival faunas can occur in the same order in different regions, immediately following the first and second phases of the Hirnantian crisis, respectively. This faunal succession records two climatic perturbations, one with a glaciation, associated with climatic cooling and a global low-stand, during which the Hirnantia Fauna flourished, and a second characterized by melting ice, global warming, and sea-level rise (with global anoxia), aligned to the development of the Edgewood-Cathay Fauna and the repopulation of the seas by many animals adapted to warmer water, e.g., metazoan reefs, massive tabulates, and sponges. Changes in many properties of the Hirnantia Fauna may have resulted from the heterogeneity of global climate change in time and space; contrasts in the Edgewood-Cathay faunas record differences between carbonate and siliciclastic deposition, respectively, at low latitudes. Intense climate changes, sea-level fluctuations, and oceanographic ventilation and anoxia, had important roles in brachiopod evolution through the Hirnantian extinctions as first taxa confined to warm-water and then cool-water conditions were the main victims. During the Hirnantian, higher originations of new taxa may have been a response to crises, which increased the rate of phyletic evolution due to extreme climatic conditions.

中文翻译：

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最新的奥陶纪 Hirnantian 腕足动物群：新的全球见解

摘要 基于来自 20 多个古板块和地体的新的综合数据集、Hirnantian 地层的修订关联方案和包括网络分析在内的数值方法，对 Hirnantian 腕足动物群的时空分布进行了审查。有两个连续的进化动物群： 1. 与早中期 Hirnantian 冰川顶点相关的广泛和历时的 Hirnantia 动物群，包括在比迄今为止设想的更复杂的环境条件下多样化的浅水、深水和深水群落；和 2. 埃奇伍德-国泰动物群（新术语）在后冰期、温暖、浅水区繁盛，在海南特晚期 - 鲁丹期早期的低纬度地区具有碳酸盐岩和硅质碎屑相。这两种生存动物群可以在不同地区以相同的顺序出现，紧接在 Hirnantian 危机的第一阶段和第二阶段之后。这种动物群演替记录了两种气候扰动，一种是冰川作用，与气候变冷和全球低位有关，在此期间 Hirnantia 动物群蓬勃发展，另一种特征是冰川融化、全球变暖和海平面上升（随着全球缺氧），与 Edgewood-Cathay 动物群的发展以及许多适应温暖水域的动物（例如后生动物珊瑚礁、大型表格和海绵）在海洋中的重新繁殖相一致。Hirnantia 动物群的许多特性的变化可能是由于全球气候变化在时间和空间上的异质性；埃奇伍德-国泰动物群中的对比分别记录了低纬度碳酸盐岩和硅质碎屑沉积物之间的差异。剧烈的气候变化，海平面波动、海洋通风和缺氧在腕足类动物进化过程中发挥着重要作用，因为首先被限制在温水中的分类群，然后是冷水条件下的主要受害者。在 Hirnantian 期间，新分类群的更高起源可能是对危机的反应，由于极端气候条件，这增加了系统进化的速度。