(Table 1) Test sizes of Morozovelloides crassatus from ODP Site 171-1052@en

We propose a phenomenon termed “pre-extinction dwarfing” in Cenozoic planktonic foraminifera. High-resolution morphometric analysis shows a reduction in maximum or mean test size in the 2-20 kyr interval preceding the extinction of Pliocene Globorotalia exilis and Globorotalia miocenica from the Caribbean Sea and middle Eocene Morozovelloides crassatus from the western North Atlantic. Through a series of case studies and review of qualitative observations from the literature, we suggest that dwarfing occurs in a number of species of planktonic foraminifera foreshadowing their demise and that such size changes are not just a phenomenon associated with mass extinction events. We propose that this is a common stress-induced pattern that results in diminutive size in the pre-extinction interval.我们提出了新生代浮游有孔虫（planktonic foraminifera）中一种被命名为“灭绝前矮化（pre-extinction dwarfing）”的现象。高分辨率形态计量分析结果显示，加勒比海盆地上新世纤细球室虫（Globorotalia exilis）与中新球室虫（Globorotalia miocenica）、西北大西洋西部中始新世厚饰莫罗球虫（Morozovelloides crassatus），在各自物种灭绝前的2至20千年（kyr）时间区间内，其壳体的最大尺寸或平均尺寸均出现缩减。通过一系列案例研究及对文献中定性观测结果的综述，我们提出，多种浮游有孔虫物种在灭绝前均会出现矮化现象，该体型变化可预示物种的消亡，且这类尺寸改变并非仅与集群灭绝事件相关。我们进一步提出，这是一种由环境胁迫诱导的普遍模式，会在物种灭绝前的阶段导致其体型小型化。