Data from: Identifying the most surprising victims of mass extinction events: an example using Late Ordovician brachiopods

Mass extinction events are recognized by increases in extinction rate and magnitude and, often, by changes in the selectivity of extinction. When considering the selective fingerprint of a particular event, not all taxon extinctions are equally informative: some would be expected even under a ‘background’ selectivity regime, whereas others would not and thus require special explanation. When evaluating possible drivers for the extinction event, the latter group is of particular interest. Here, we introduce a simple method for identifying these most surprising victims of extinction events by training models on background extinction intervals and using these models to make per-taxon assessments of ‘expected’ risk during the extinction interval. As an example, we examine brachiopod genus extinctions during the Late Ordovician Mass Extinction and show that extinction of genera in the deep-water ‘Foliomena fauna’ was particularly unexpected given preceding Late Ordovician extinction patterns.大灭绝事件的识别依据为灭绝速率与灭绝规模的升高，且通常伴随灭绝选择性的变化。在分析某一特定灭绝事件的选择性特征时，并非所有类群的灭绝都具有同等的信息价值：部分类群的灭绝即便在“背景”选择性机制下也可预期，而另一部分类群的灭绝则无法通过背景机制解释，因此需要特殊解释。在探究该灭绝事件的潜在驱动因素时，后一类类群尤为关键。本研究提出一种简便方法：通过在背景灭绝区间训练模型，并利用该模型对灭绝区间内各分类群的“预期”灭绝风险进行逐类评估，以此识别灭绝事件中最具意外性的受灾类群。以晚奥陶世大灭绝（Late Ordovician Mass Extinction）期间的腕足动物属级灭绝事件为例，本研究证实：结合此前的晚奥陶世灭绝模式来看，深水“Foliomena 动物群（Foliomena fauna）”内各属的灭绝具有显著的意外性。