The double mass extinction revisited: reassessing the severity, selectivity, and causes of the end-Guadalupian biotic crisis (Late Permian)
The double mass extinction revisited: reassessing the severity, selectivity, and causes of the end-Guadalupian biotic crisis (Late Permian)
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DOI：
10.1666/08033.1
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发表时间：
2009-12-01
期刊：
影响因子：
2.7
通讯作者：
Bottjer, David J.
中科院分区：
文献类型：
--
作者：
Clapham, Matthew E.;Shen, Shuzhong;Bottjer, David J.
中二叠世末期的瓜达卢佩灭绝被认为是中生代最大的生物危机之一。先前的估计表明，危机消除了58%的海洋无脊椎动物属在Capitanian阶段，它的选择性帮助现代进化动物群变得比古生代动物群更多样化，在二叠纪末大规模灭绝之前。然而，一个新的采样标准化分析二叠纪的多样性趋势，基于53731海洋无脊椎动物化石发生从9790个集合，表明结束瓜达卢佩“灭绝”实际上是一个长期的，但逐渐减少的多样性从Wordian到二叠纪结束。有没有灭绝率的峰值;减少属丰富度表现出所有研究的无脊椎动物群体和生态公会，并在不同的纬度带，而是驱动的起源率急剧下降，在Capitanian和Wuchiapingian。全球多样性的减少加剧了β多样性的变化，最显着的是减少省级由于海洋栖息地面积的损失和一个明显的减少在小距离的地理差异。在中等到大的距离的差异是不变的，这表明小规模的β多样性变化可能是由于压缩的测深范围和均匀化的海岸-近海动物群梯度产生的深水缺氧周围的瓜达卢佩/Lopingian边界的蔓延。虽然热带无脊椎动物属并不比热带以外的物种灭绝的可能性更大，但在Capitanian和Wuchiapingian期间，起源率的显着降低与全球变冷（Kamura事件）的影响是一致的，但也可能与其他环境压力（如缺氧）一致。然而，逐渐减少的多样性，而不是急剧结束瓜达卢佩灭绝，排除了需要调用激烈的灭绝机制，并表明在古生代末的分类损失集中在传统的二叠纪末（结束长兴）灭绝，消除了78%的所有海洋无脊椎动物属。
The end-Guadalupian extinction, at the end of the Middle Permian, is thought to have been one of the largest biotic crises in the Phanerozoic. Previous estimates suggest that the crisis eliminated 58% of marine invertebrate genera during the Capitanian stage and that its selectivity helped the Modern evolutionary fauna become more diverse than the Paleozoic fauna before the end-Permian mass extinction. However, a new sampling-standardized analysis of Permian diversity trends, based on 53731 marine invertebrate fossil Occurrences from 9790 collections, indicates that the end-Guadalupian "extinction" was actually a prolonged but gradual decrease in diversity from the Wordian to the end of the Permian. There was no peak in extinction rates; reduced genus richness exhibited by all studied invertebrate groups and ecological guilds, and in different latitudinal belts, was instead driven by a sharp decrease in origination rates during the Capitanian and Wuchiapingian. The global diversity decrease was exacerbated by changes in beta diversity most notably a reduction in provinciality due to the loss of marine habitat area and a pronounce decrease in geographic disparity over small distances. Disparity over moderate to large distances was unchanged, suggesting that small-scale beta diversity changes may have resulted from compression of bathymetric ranges and homogenization of on shore-offshore faunal gradients stemming from the spread of deep-water anoxia around the Guadalupian/Lopingian boundary. Although tropical invertebrate genera were no more likely than extratropical ones to become extinct, the marked reduction in origination rate,; during the Capitanian and Wuchiapingian is consistent with the effects of global cooling (the Kamura Event), but may also be consistent with other environmental stresses such as anoxia. However, a gradual reduction in diversity, rather than a sharp end-Guadalupian extinction, precludes the need to invoke drastic extinction mechanisms and indicates that taxonomic loss at the end of the Paleozoic was concentrated in the traditional end-Permian (end-Changhsingian) extinction, which eliminated 78% of all marine invertebrate genera.