The Palaeozoic colonization of the water column and the rise of global nekton

The colonization of the water column is among the most important transformations in the evolution of animal life and global ecosystems. The Devonian Nekton Revolution (DNR) has been identified as a major macroevolutionary event signifying the sudden occupation of the water column by independent radiations of swimming animals. Using new data, an expanded taxonomic coverage, sample standardization, and increased ecological resolution, we reanalysed the timing, duration, and magnitude of this event. We find that nekton and eunekton were well established prior to the Devonian and did not diversify dramatically during any Palaeozoic interval. Relative nektic diversity and occurrences decreased rather than increased during the Devonian. Eunektic diversity and occurrences increased throughout the Palaeozoic, but this rise was protracted and cannot be attributed to any single interval. Our new data indicate that the metazoan colonization of the water column was considerably more complex and gra...水体柱（water column）的殖民化是动物生命演化与全球生态系统变革历程中最为关键的转变之一。泥盆纪游泳生物革命（Devonian Nekton Revolution, DNR）已被确认为一项重要宏演化事件，其标志为独立辐射演化的游泳动物突然占据水体柱。本研究依托全新数据集、拓展的分类学覆盖范围、标准化的样品处理方案以及提升后的生态分辨率，重新解析了该事件的发生时间、持续时长与影响规模。研究结果显示，游泳生物（nekton）与真游泳生物（eunekton）早在泥盆纪之前就已形成稳定种群，且在古生代任一地质时段均未发生显著的辐射演化；相对游泳生物多样性与出现频次在泥盆纪期间反而呈下降趋势。真游泳生物的多样性与出现频次在整个古生代均持续上升，但这一增长过程极为漫长，无法将其归因于某一单独地质时段。本研究的新数据表明，后生动物（metazoan）对水体柱的殖民化过程远比此前认知更为复杂，且