Key stages in the evolution of the Antarctic marine fauna
Key stages in the evolution of the Antarctic marine fauna
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DOI：
10.1111/jbi.13208
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发表时间：
2018-05-01
影响因子：
3.9
通讯作者：
Crame, J. Alistair
中科院分区：
文献类型：
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作者：
Crame, J. Alistair
我们开始意识到，现代南极海洋动物群的起源与整个新生代的一系列关键事件有关。在第一个这些，大规模灭绝在古近纪边界（66马）重置的进化阶段，并导致了现代类群在底栖领域的主要辐射。虽然这发生在一个温室世界，但有证据表明，辐射受到初级生产力季节性的调节，这可能是极地地区的一个不随时间变化的特征。虽然有可能是一个单一的，突然的灭绝事件在c.34马，也有证据表明，一个阶段性灭绝的各种类群在一段时间的数百万年。重要的新的分子系统发育数据表明，各种各样的底栖和远洋类群辐射后不久，第二个主要阶段的冷却在约14马。这种现象与一系列重大的古海洋学变化有关，而这些变化又导致了以海洋为基础的生态系统的扩散。虽然现代底栖海洋动物可以追溯到大约4500万至5000万年前，但现代远洋动物的一个重要组成部分可能不到1400万年。后者的特点也是高丰度的组合，但相对较低的物种丰富度和均匀度。在整个新生代，温度和初级生产力之间的相互作用维持了南极海洋生物组合中低多样性但高优势的独特特征。
We are beginning to appreciate that the origin of the modern Antarctic marine fauna is related to a series of key events throughout the Cenozoic era. In the first of these, the mass extinction at the Cretaceous-Palaeogene boundary (66 Ma) reset the evolutionary stage and led to a major radiation of modern taxa in the benthic realm. Although this took place in a greenhouse world, there is evidence to suggest that the radiation was tempered by the seasonality of primary productivity, and this may be a time-invariant feature of the polar regions. Although there could well have been a single, abrupt extinction event at c.34 Ma, there is also evidence to suggest a phased extinction of various taxa over a period of millions of years. Important new molecular phylogenetic data are indicating that a wide variety of both benthic and pelagic taxa radiated shortly after a second major phase of cooling at c.14 Ma. Such a phenomenon is linked to a series of major palaeoceanographic changes, which in turn led to a proliferation of diatom-based ecosystems. Although the modern benthic marine fauna can be traced back some 45-50 Myr, a substantial component of the modern pelagic one may be less than 14 Myr old. The latter is also characterized by assemblages of high abundance but comparatively low species richness and evenness. A distinctive signature of low diversity but high dominance within Antarctic marine assemblages was maintained by the interplay between temperature and primary productivity throughout the Cenozoic.